University Of Chicago

NIH Research Projects · FY 2025 · 2024-03

This developmental research grant award (R21) requests funds to characterize the social and transmission networks of migrant workers in Greece as part of pandemic preparedness, to mitigate ongoing and future coronavirus epidemics among vulnerable populations in diverse contexts. We aim to better understand COVID-19 prevention, testing, treatment, vaccination, seroprevalence and immunogenicity in order to address facilitators and barriers to COVID-19 prevention. Migrant workers comprise one of the foremost essential worker categories, are at increased risk of COVID-19 transmission and at the same time have some of the lowest rates of testing and vaccination. Critical to public health is improving COVID-19 prevention among these populations and their larger social networks. Network analysis can better illuminate ongoing transmission dynamics and the potential for future epidemics. Contact tracing and other strategies do not fully include the larger social network and data are often limited due to the stigma associated with providing named contacts, as well as mistrust in government, particularly for migrant workers subject to harsh immigration policies. Social network analysis, following traditional egocentric network approaches that this team has expertise in, can illuminate multiple networks (family, workplace, acquaintance) and develop metrics tied to disease transmission such as density, bridging and transitivity. In addition, network analysis can better explain transmission potential phenomena such as sharing of resources across household units, workplace networks and other transmission potentials. Understanding the potential transmission dynamics would help develop tailored interventions to limit the explosive transmission documented in the US and Europe. The study context and team are ideal for this proposal. Athens Greece is the entry point to the largest migrant population in the EU and Bangladeshi migrants are the second largest constituency. Although the target population is very specific, it represents an extremely important stream of global migration that connects two populous world regions, with salient epidemiological consequences for the entire globe. The PI has a track record of collaborative work implementing participant recruitment protocols in Athens among vulnerable populations through street based and community focused engagement. The PI and site-PI are joined by additional experts in virology, demography and South Asian and migrant health. Accordingly, we aim to: 1) Characterize the social networks of Bangladeshi migrant workers in Athens and measure features of their network structures - degree, density and bridging – most relevant to COVID-19 transmission potential; 2) Determine individual (ie. age, gender), contextual (ie employment type), network and health care access factors associated temporally with SARS-CoV-2 infection, seroprevalence and immunogenicity status. We will collect survey data and biologic samples to model COVID-19 transmission; and 3) Determine individual and network level factors associated with prevention behaviors: social distancing, masking, testing and vaccination.

NIH Research Projects · FY 2026 · 2024-03

PROJECT SUMMARY/ABSTRACT Cellular senescence is a state of irreversible cell cycle arrest associated with macromolecular damage and secretion of senescence-associated secretory phenotype (SASP), which includes cytokines, chemokines, and growth factors. The SASP provides immune surveillance that recruits immune cells to clear senescent cells; however, persistent senescence or enduring SASP production that exceeds immune clearance aggravates inflammatory injuries. Ageing is a major driver of tissue senescence. Age-related accumulation of cellular senescence is a major pathogenic factor responsible for the decline of tissue function and the increase in age- related pathologies, but little is known about the molecular mechanism that drives tissue senescence. On the other hand, age-unrelated senescence and its pathophysiological impact are understudied. For example, very little is known about metabolic control of colonic senescence, its molecular mechanism and pathophysiological consequences. Our goal is to tackle these questions and fill the knowledge gaps. Our preliminary studies demonstrated that colon epithelial acetyl-CoA deficiency triggers robust p53-dependent colonic senescence, and the accompanying SASP induces severe mucosal and systemic inflammation leading to premature death in mice. Further investigation revealed that epithelial senescence and SASP are closely associated with inflammatory bowel disease (IBD) in both mouse colitis models and human patients. We also discovered that gut microbe-derived acetate helps maintain host's epithelial acetyl-CoA pool to prevent colonic senescence. Our data suggest that the acetyl-CoA status of colonic epithelial cells is determined by host ATP-citrate lyase (Acly), acetyl-CoA synthetase 2 (Acss2) and microbe-derived acetate; as such, gut dysbiosis, in the presence of Acly and Acss2 down-regulation, leads to acetyl-CoA deficiency that triggers colonic senescence. Our findings shed new lights on the development of age-unrelated colonic senescence and its pathogenic connection to mucosal inflammation and colitis, and suggest that colonic senescence presents a novel therapeutic target for IBD. To extend this investigation, we propose three Aims. In Aim 1 we will assess the effect of acetyl-CoA deficiency in intestinal stem cells on colonic homeostasis. In Aim 2 we will elucidate the molecular mechanism whereby nuclear/cytosolic acetyl-CoA deficiency triggers colonic senescence. In Aim 3 we will explore colonic senescence as a pathogenic driver as well as a novel therapeutic target of IBD. There are vast knowledge gaps about age-unrelated colonic senescence and its pathological effects. There are huge unmet needs for IBD therapy. This project will provide new mechanistic insights into metabolic control of colonic senescence, and unveil the critical roles of acetyl-CoA and microbe-derived acetate in the regulation of colonic senescence. For translational value, this project will uncover the link of colonic senescence to IBD pathogenesis and prove senescence not only as a novel biomarker of IBD but also as potential therapeutic target for IBD management.

NIH Research Projects · FY 2026 · 2024-03

Abstract The overarching goal of this proposal is to obtain general principles of dendritic computation. The starburst amacrine cell (SAC) of the mammalian retina is an excellent model to study dendritic function because it has a rich set of generic dendritic processing machineries and a well-defined computation – direction selectivity. Its radially oriented dendritic sectors are tuned to different directions of visual motion stimuli, and thereby confer direction selectivity to the output neurons of the retina. Previous studies have generated substantial knowledge on the spatiotemporal patterns of synaptic inputs onto the SAC dendritic arbor. However, how motion-evoked inputs are transformed by SAC dendrites to generate robust outward direction selectivity is not well understood. This application therefore focuses on the dendritic mechanism and how it is influenced by the synaptic input. We will obtain the objective of the proposed research using a combination of patch clamp recording, two-photon calcium, glutamate and voltage imaging during visual stimulation, and behavioral assay. Insights from this proposal will challenge the conventional view that synaptic inputs are processed by dendrites equipped with a stable set of intrinsic biophysical properties. Our study will advance the field of dendritic computation by establishing a more dynamic relationship between synaptic activity and the algorithm of dendritic integration.

NIH Research Projects · FY 2026 · 2024-03

PROJECT SUMMARY Commensal microbes are indispensable for healthy physiology of their eukaryotic hosts and provide essential functions required for host survival, including nutrition and colonization resistance, and perform accessory functions, including immune system development, vascularization, and contribute to behavior. Composition of the microbiome is shaped by many factors. Some influences are acute, such as diet and infection, which rapidly change the commensal population, but it returns to its pre-challenge composition. On the other hand, the genetics of the host have a constant influence on the microbial composition. While increasing pieces of evidence point to host genetics playing a critical role in shaping the microbiome, how it does so is adversely understudied. To eliminate the influence of environmental factors and study only the role of host genetics in shaping the microbiome, a murine model of legacy-independent host-commensal interactions was developed. This model provided the foundational blueprint establishing that the microbiome is impacted by host mechanisms, but how they are impacted has to be investigated. Herein, we describe how we developing this model to dissect the role of host genetics in specific host- commensal interactions. We have identified that the population of Lactobacillus murinus, a prominent member of the gut microbiome, is directly shaped by host genetics. Through an interdisciplinary approach spanning immunology, microbiology, and genetics, we will determine the mechanism directly influencing the intestinal population of Lactobacilli. The proposed experiments will provide an experimental platform by which any host- commensal relationship driven by host genetics can be identified and the mechanism can be determined. Drs. Golovkina and Chervonsky are ideal sponsor and co-sponsor, respectively, for this project. Not only did they establish the legacy-independent host-commensal model, but they are also experts in the fields of microbiology, immunology, and genetics. Dr. Golovkina is a mouse geneticist who has built her career on using inbred mouse strains to identify genes driving phenotypic differences in host-pathogen interactions and co- established the field of microbiome-virus pathogen interactions. Dr. Chervonsky is a renowned immunologist and expert in host-commensal interactions and the influence of the microbiome on autoimmunity. He is also the co-director of the Gnotobiotic Component of the Host-Microbe Core at the University of Chicago. Their laboratories are uniquely situated to support my efforts to study the gnotobiotic models necessary to delineate host-commensal interactions through rigorous genetic studies. They are dedicated mentors to my academic, scientific career at the bench and beyond. All necessary resources to conduct the proposed experiments are found either in the labs already or on campus at the University of Chicago. In addition to having many resources available for scientific use, the University of Chicago is a fantastic training center for postdoctoral trainees.

NIH Research Projects · FY 2025 · 2024-02

Project Summary Status epilepticus (SE) is a neurologic emergency associated with high risk of neurologic decline and readmission. Mortality, length of stay, and cost all increase when patients in SE progress to refractory status epilepticus (RSE). SE is clinically heterogenous and broadly defined, which is a barrier to conducting randomized trials and contributes to pervasive diagnostic delays and treatment variability. Further, rare subtypes of SE, such as New-onset refractory status epilepticus (NORSE) remain poorly understood. Case definitions that are extractible from the electronic health record (EHR) are necessary for a population-level approach to surveillance of SE, including NORSE, aimed at identifying high risk groups and associated conditions and exposures, supporting early diagnosis, determining incidence, establishing natural history and targeting of therapies. EHR and administrative case definitions for SE do not exist, and current methods of identifying patients with SE using only structured EHR data are prone to bias. In general, prediction models using only structured data often have limited utility. To our knowledge, our proposed project is the first attempt at large-scale multidimensional phenotyping for SE using unstructured data. We hypothesize that generating consensus around the spectrum of clinical phenotypes of SE and using Natural Language Processing (NLP), to identify and classify SE is an essential first step for the creation of SE registries and comparative effectiveness and pragmatic trials of RSE prevention. In Aim 1, we will apply an innovative sequential mixed methods approach, using (a) a modified Delphi method to establish consensus around labels to identify relevant information elements (“ground truth”) and (b) a discrete choice experiment (DCE) to rank identify time-evolving attributes of SE. This will allow us to study whether attributes are weighted differently during a SE admission, and whether risk trajectories toward developing RSE are identifiable. In Aim 2, we will leverage unstructured EHR data from two large academic centers and apply NLP to develop a standardized data extraction model of symptom dimensions, clinical features, and complex concepts of SE from EHRs. Such a model could then categorize SE by clinical outcomes, specifically RSE. Such a tool lays an essential foundation for future comparative effectiveness and pragmatic trials of potentially modifiable preventive factors of RSE, leading to the development of clinical decision support tools, quality metrics, and performance measures for SE and RSE management.

NIH Research Projects · FY 2025 · 2024-02

SUMMARY Acinetobacter baumannii is an emerging nosocomial pathogen and a leading global cause of ventilator- associated pneumonia. This pathogen also infects a number of other anatomical sites, resulting in wound, urinary tract, and bloodstream infections, meningitis, and endocarditis. A. baumannii infections are extremely recalcitrant to therapeutic interventions, largely due to the acquisition of antibiotic resistance by this pathogen. Nosocomial transmissions of A. baumannii frequently occur in critically ill hospital patients, typically following contact with contaminated hospital surfaces, personnel, or medical devices. Bacteria persisting on hospital surfaces must tolerate an onslaught of environmental stresses, principal among them being the loss of water, or desiccation. A. baumannii is extremely desiccation tolerant and this phenotype is observed across a wide spectrum of clinical and laboratory isolates, suggesting that genes promoting desiccation tolerance are broadly conserved in this pathogen. However, the factors promoting desiccation tolerance in A. baumannii remain largely undefined. Additionally, it is well established that exposure to environmental stresses modulates the virulence of A. baumannii; however, the impact that persistence in a desiccated state has on the transmission and virulence of A. baumannii has not been explored. In preliminary experiments, we have discovered that Lon protease serves as a critical regulator of the A. baumannii response to desiccation and we have determined that Lon regulates the expression of a highly disordered protein, DtpA, which is required for the extreme desiccation tolerance of this organism. Additionally, we have found that desiccated A. baumannii causes more virulent disease in a murine model of pneumonia, suggesting that factors required to tolerate desiccation may promote pathogenesis within the mammalian host. Here, we propose to determine the molecular mechanisms underlying these phenotypes and reveal the mechanisms linking environmental persistence and pathogenicity in A. baumannii by 1) defining the mechanism of Lon protease-mediated regulation of dtpA transcription, 2) elucidating the regulation and function of Lon protease in response to desiccation, and 3) interrogating the molecular link between A. baumannii desiccation tolerance and virulence. Together, these studies will improve our understanding of how A. baumannii persists in the environment and define the impact that environmental persistence has on the transmission of this emerging pathogen. Additionally, findings from this work may be applied to the study of other nosocomial pathogens to more broadly understand how bacterial transmission occurs in hospital settings.

NIH Research Projects · FY 2025 · 2024-02

The classic example of supervised learning occurs at the parallel fiber (PF) to Purkinje cell synapse in the cerebellum, where plasticity depends on co-activity of the climbing fiber (CF) input, which – according to the theories of Marr, Albus and Ito – provides the error signal. In a wider interpretation, this signal is instructive in nature, and might be related to error, sensory omission, as well as reward or reward-prediction. Depending on the proper timing intervals between the two stimuli, CF co-activity with the PF input promotes synaptic long- term depression (LTD) at PF synapses and thus helps to optimize synaptic input weights. This well-studied function of CFs within the cerebellar system is in stark contrast to what is known about the potential relevance of CF activity outside of the cerebellum. A plausible anatomical pathway for various interactions with neocortical areas has been described, which includes activation of Purkinje cells, and the subsequent signal transfer via cerebellar nuclei and thalamic nuclei, e.g. the ventral lateral (VL) and posteriormedial nuclei (Pom). Here, we ask whether CF co-activity can provide an instructive signal that affects receptive field (RF) plasticity in the primary somatosensory (S1; barrel) cortex of mice. Preliminary data from our laboratory show that repetitive activation of individual whiskers enhances whisker representation in the barrel cortex as assessed by intrinsic optical imaging. Optogenetic co-activation of channelrhodopsin 2 (ChR2)-expressing CFs in the cerebellum suppresses this form of cortical RF plasticity. These data show that indeed CF signaling may act as an instructive signal for plasticity outside of the cerebellum and supervises learning in the neocortex. However, intrinsic imaging does not provide information about participating cellular structures, e.g. which neurons change in this form of RF plasticity and which neurons ultimately mediate the effects of CF activity. In this study, we propose to use two-photon microscopy and optogenetics in awake mice to address the following questions. First, we will assess how whisker stimulation affects S1 cortex circuitry (aim 1). We will test the hypothesis that the RF plasticity observed with intrinsic imaging is due to an increase in the activity of L2/3 pyramidal neurons. We will also zoom in on parvalbumin-expressing (PV+) interneurons to follow up on our pilot data that show that these PV+ interneurons downregulate their activity after whisker tetanization. Second, we will examine how optogenetic co-activation of CF terminals in the cerebellum with 470nm light pulses impairs activity changes in these neuronal populations (aim 2). Next to pyramidal neurons, our focus will again be on PV+ interneurons, as our pilot data show that optogenetic CF stimulation drives activation of these inhibitory neurons, thus providing a potential pathway for the observed impact on the cortical network. Third, we will study whether direct optogenetic Purkinje cell activation mimics the effects of CF activation, addressing the question whether CFs act via the cerebellar cortex or a direct effect on the cerebellar nuclei (aim 3). This work will be the first to investigate whether CF signaling has an instructive role beyond the cerebellum.

NIH Research Projects · FY 2026 · 2024-02

The intestinal tract is comprised of functionally different regions, each having distinct and highly selected microbiota assembled through evolutionary and ecological drivers to achieve a mutualistic relationship important to host health. However, with ever increasing shifts in environment, diet, lifestyles, and prevalent use of antibiotics it is becoming evident that perturbations of host-microbial balance affect states of health and give rise to a multitude of disorders. This recognition has fostered interest in “natural” remedies such as Fecal Microbiota Transplant (FMT) and Live Biotherapeutic Products (LBPs) to maintain or restore gut microbiota health in patients with Clostridioides difficile infection and other disorders (IBD, metabolic disorders). However, one has to question the appropriateness of these preparations, given that most are comprised of colonic anaerobic microbes not indigenous or fit to inhabit the small intestine. Mismatches between regional host gut ecosystems and their microbiota could have adverse consequences to the host. This possibility leads us to hypothesize that colonic microbiota of FMT will not properly restore the microbiome of the small intestine (and vice versa) and that this will have long-term regional and systemic consequences. Our preliminary data show merit for this hypothesis, i.e., the engraftment of donor microbiota in non-indigenous ecosystems create mismatches that lead to regional and systemic consequences particularly of immune and metabolic networks that persist at least 3 months in a post-antibiotic (Abx) microbial transplant murine model. Planned studies will employ in vivo and in vitro experimental models to assess the long-term impact (one-year post transplant) of regional microbiota on host tissues because studies of this nature are technically challenging if not infeasible in human subjects. We propose two specific aims: (1) to examine to what extent do post-Abx jejunal (JMT) vs fecal (FMT) microbiota transplants restore regional gut microbiota composition and function, and host immune and metabolic function following antibiotic-induced dysbiosis compared to cecal microbiota transplant (CMT) and saline controls; and (2) to determine the direct impact of JMT vs FMT-specific microbes identified through a novel cross ‘omics bioinformatic integration platform and their metabolites on host metabolism and immune function using in vivo and in vitro approaches. To reflect the cut in the budget, we propose assessing outcomes after one year of transplant vs assessing outcomes at also 3 and 6 months given that we have extensive preliminary data for the earlier time points. Findings of Aim 1 will raise awareness of the potential concerns of improper restitution of regional gut microbiota with microbiota transplants that may require a rethinking of current FMT practices and LBP formulations. Aim 2 will provide insights to how to solve the problem, creating a new path for future and more strategic development of effective and safe omni-microbial transplants (OMTs). This multi-PI study stems from a long-time collaboration between laboratories of Drs. Eugene Chang and Kristina Martinez-Guryn that have complementary expertise in the study of immunity and metabolism.

NIH Research Projects · FY 2025 · 2024-02

Project Summary The University of Chicago (UChicago) Initiative for Maximizing Student Development (IMSD) is designed to provide research training and educational opportunities for newly admitted PhD graduate students from groups underrepresented (UR) in the biomedical and behavioral sciences and our programming is open to non-UR students who would benefit from IMSD opportunities. The Program is tiered to focus intervention and developmental activities to match the background preparation, research experience, and learning styles of individual students as well as their stage of progression in graduate school. Students join the IMSD in the Summer term upon entry to graduate studies, complete an Individual Development Plan (IDP) that will serve as the roadmap for each student's course over their tenure in the UChicago IMSD, and participate in a Summer Research Program that helps to integrate them into the Graduate Programs and prepare them for the rigors of a UChicago graduate education. Navigation through rotations and coursework, as well as developing communication and coping skills will be facilitated through Interactive Learning Modules (ILMs) and augmented by peer and faculty mentoring. Support from the Program is provided for years one through three of graduate school. Students remain members of the IMSD program while advancing to completion of the PhD, benefitting from ILMs designed to hone scientific skills, enhance leadership skills, develop professional and networking skills and explore career options. Although the Program is highly structured and logically organized, it is also customizable depending on each student’s needs. This is accomplished by a newly developed skill-based evaluation process implemented at key milestones. Faculty are actively engaged in improving their mentoring and training skills, while all stakeholders work together toward a more diverse community of scholars. The ultimate success of the IMSD Program is measured by completion of the students’ PhD programs, their long- term success as biomedical scientists, and an increase in the diversity of the biomedical research community over time.

NIH Research Projects · FY 2026 · 2024-02

ABSTRACT The broad and long-term objective of our research inquiry is to develop receiver operating characteristic (ROC) analysis towards a broadly applicable, practical, accurate, precise, efficient, and user-friendly method for evaluation of diagnostic performance in medical imaging and beyond. The objective of this project is to develop an innovative weighted ROC (WROC) analysis. The central hypothesis is that, by introducing a case weighting factor, WROC analysis can mitigate and eliminate bias in ROC analysis from non-random case samples and infer clinical performance without bias. Specific Aims are: (1) develop WROC algorithms and share analysis software with the research community; (2) develop and validate three WROC analysis applications; and (3) investigate with WROC analysis pivotal ROC study inference bias from non-random case samples. Research design, based on contemporary ROC methodologies and preliminary studies, will be to expand the basic ROC theory by introducing a weight factor to every case, and to develop WROC estimation algorithms for common ROC models including the non-parametric, conventional binormal, and proper binormal models, to develop new WROC software, which will supersede existing ROC software, and to make the new software available to the research community by developing an open, easy-to-use, feature-rich, and publication-friendly online calculator. New WROC algorithms will be used to develop three new applications: to compare meaningfully ROC studies of non-random and non-identical case samples, to design ROC studies with stratified case samples and then apply WROC analysis to model case sample distributions to match random sampling and infer random-sample ROC performance without bias, and to estimate aggregate ROC performance of multiple readers by averaging individual-reader ROC curves weighted by clinical case volume. Finally, WROC analysis will be used to investigate bias in the inference to clinical performance from multi- reader multi-case (MRMC) studies of non-random case samples and WROC analysis as a means to overcome this bias. Methods to be used include mathematical derivation of maximum-likelihood estimations, software development, and validation with Monte Calo simulations. The proposed WROC analysis is premised on weighing cases unequally. This simple addition of a case weight will add a new dimension to ROC analysis. Practical benefits include added analysis flexibility, improved clinical performance inference from laboratory studies, and new ways to design better reader studies. The importance and health relatedness of this research is that once developed, validated, and made available to and used by the research community, the new development will be one step that advances ROC analysis towards a broadly applicable, practical, accurate, precise, efficient, and user-friendly method for diagnostic performance evaluation.

NIH Research Projects · FY 2025 · 2024-02

Summary and Relevance of Proposed Research Humans have a remarkable capacity to learn to recognize the significance of visual stimuli. This ability, which is disrupted by a brain-based diseases and conditions such as Alzheimer’s disease, schizophrenia, stroke, and attention deficit disorder, is critical because it allows us to learn about the meaning of the stimuli that we encounter, and it enables us to make appropriate decisions. Our recent work examined the roles of a network of cortical and subcortical areas to visual category decisions, including posterior parietal cortex (PPC), frontal eye field (FEF), and superior colliculus (SC). However, those previous studies only examined these regions after weeks or months of training required to learn the categorization tasks. The long training required to learn those tasks precluded studying mechanisms by which neural category encoding developed during the learning process itself. This project develops a novel paradigm for studying rapid within-session category learning using a saccade-based foraging paradigm which takes advantage of subjects’ innate ability to search among arrays of visual stimuli with saccades. In this paradigm, subjects are presented with arrays of stimuli belonging to two or three categories, with each category associated with a different reward amount. Subjects must search or “forage” among stimuli by making self-guided saccades to obtain the reward associated with each target image. During foraging-based learning, population recordings will monitor PPC, SC, FEF, and orbitofrontal cortex (OFC). We will also assess the causal contributions of these regions using reversible inactivation during task performance. This will determine how interactions between neurons in these regions enable rapid category learning and transforming category recognition into stimulus selection and saccadic motor plans. While much is known about how the brain processes visual features (such as color, orientation, and direction of motion), less is known about how the brain learns and represents the meaning, or category, of stimuli. A greater understanding of visual categorization is critical for addressing a number of brain diseases and conditions (e.g. stroke, Alzheimer’s disease, attention deficit disorder, schizophrenia, and stroke) that leave patients impaired in everyday tasks that require visual learning, recognition and/or evaluating and responding appropriately to sensory information. The long-term goal of this project is to guide the next generation of treatments for these brain-based diseases and disorders by helping to develop a detailed understanding of the brain mechanisms that underlie learning, memory and recognition. These studies also have relevance for understanding and addressing learning disabilities, such as attention deficit disorder and dyslexia, which affect a substantial fraction of school age children and young adults. Thus, a detailed understanding of the basic brain mechanisms of categorical decisions and attention will likely give important insights into the causes and potential treatments for disorders involving these cognitive and perceptual abilities.

NIH Research Projects · FY 2026 · 2024-02

Project Summary My group seeks to understand, at a fundamental level, the function of voltage-gated potassium (Kv) and sodium (Nav) channels using molecular dynamics (MD) simulations based on atomic models. Despite the enormous progress in structure determination, our comprehension of ion permeation, selectivity, activation, inactivation and regulation remains incomplete. It is also crucial to keep in mind that a biological membrane is much more than a simple passive and featureless environment, but a complex dynamical molecular supra-assembly. The activity of ion channels is affected by a hosts of factors associated with the membrane, often modulated by ion-mediated electrostatic interactions. Lipids are also directly involved in the activation of specific channels and signaling. MD simulations based on atomic models can play an important role in understanding the fundamental physical forces driving the structure and dynamics of these complex biomolecular systems. Using MD, we will study mechanism of selective ion permeation (knock-on v.s. hard-knock) and the molecular basis of voltage-activation as well as C-type inactivation. The latter will examine the classic inactivating W434F Shaker K+ channel mutant based on recent structural information from cryo-EM and X-ray crystallography. On the experimental side, we continue to investigate the factors affecting the activation and inactivation of K+ channels using cryo-EM and X-ray crystallography. We will also expand the scope of our research by examining the function of Nav channels, including selectivity, permeation, activation, and inactivation. To obtain meaningful computational results from MD simulations, it is crucial to accurately model the physical forces associated with changes in the electronic distribution, a need that has stimulated the development of polarizable models going back many decades. Our efforts have focused on developing a polarizable force field (FF) in the context of the classical Drude oscillator model. The Drude model covers many molecular components and has been implemented in many simulation programs (CHARMM, NAMD, GROMACS, OPENMM, and the CHEMSHELL QM/MM software). However, there is a critical need to expand the type of phospholipids covered to enable the modeling of a broader range of biomembrane processes. We will develop the FF for the most important charged lipids like phosphatidylserine (PS) and phosphatidylglycerol (PG), and explore the biology of phosphatidylinositol-4,5-bisphosphate (PIP2). Calculations of the permeability coefficient of small molecules will be used to validate the optimized FF. We will also undertake several technical developments on the propagation of the Drude model, enhanced sampling, conformational sampling, and machine learning algorithms, etc. The planned simulation studies based on an accurate and computationally efficient polarizable FF promise new fundamental insight into the function of ion channels and a host of biomembrane phenomena. 1

NIH Research Projects · FY 2025 · 2024-02

Project summary The clinical manifestations of autism spectrum disorder (ASD) and related neurodevelopmental disorders (NDDs) are thought to be caused by an imbalance of excitatory and inhibitory neuronal activity. We have discovered that changes in activity cause long-term changes in the intracellular architecture of neurons. The long-term changes occur through the formation of novel organelles, called Golgi satellites (GSats), that have many of the functions of the Golgi apparatus (GA) in the soma. Preliminary data demonstrate that activity changes cause GSats to position at synapses, particularly in dendrites at spine heads. Preliminary data also show that the ASD- and NDD-related protein Ube3a localizes to GSats, and that this association is increased in response to neuronal stimulation. At dendritic synaptic sites, GSats are the “missing” organelles needed for proper glycosylation of locally translated membrane and secreted proteins important for synaptic plasticity. GSat formation transforms local secretory pathways at postsynaptic sites so that locally translated membrane and secreted proteins are properly glycosylated. In addition, multiple glycoproteins which are both associated with ASD and involved in synaptic function are endocytosed into early endosomes and then trafficked into GSats where glycans can again be processed. Through these functions, GSats can remodel the neuronal surface glycoproteome and mediate rapid changes in the sialic acid content of synaptic glycoproteins. These processes can lead to changes in protein function which can then contribute to the altered synaptic function observed in ASD and NDDs. In this proposal we will examine how GSats interact with the products of the ASD- and NDD-risk gene UBE3A. The association of Ube3a with GSats is hypothesized to regulate GSat acidification, which in turn influences the activity of resident sialyltransfereases and their ability to remodel the neuronal surface glycoproteome and rapidly alter synaptic protein sialic contents. We will determine how changes in Ube3a expression alters sialic acid content at synapses and on a set of synaptic and ASD-related glycoproteins. We will also characterize how changes in Ube3a expression regulate activity-induced modulation of GSat formation and localization in relative to synapse, how these changes correlate with synaptic plasticity. We have developed a series of techniques, assays and preparations that will allow us to perform these experiments in both primary neuronal cultures and in ex vivo mouse hippocampal preparations.

NIH Research Projects · FY 2026 · 2024-01

Project Summary/Abstract Increasing evidence has demonstrated that disease states of either endocrine or exocrine pancreas aggravate one another, which implies bi-directional blood flow between islets and exocrine cells. However, this is inconsistent with the current model of uni-directional blood flow, which is strictly from islets to exocrine tissues, termed insulo-acinar portal system. Furthermore, exocrine and endocrine compartments of the pancreas have been studied by different scientific communities, and the diseases of them are treated by physicians in different medical disciplines, gastroenterologists and endocrinologists, respectively. Notably, it is still unknown why pancreatic islets, consisting only 1-2% of the pancreas, are embedded in the bulk exocrine tissue as one organ. We have previously shown that islet microcirculation is integrated with that of surrounding exocrine tissue at its entirety through intravital in vivo recordings of fluorescent-labeled red blood cell flow as well as in situ imaging of pancreas vasculature using thick tissue blocks. This new model of the bi-directional blood flow physically links both compartments. Further anatomical analysis of the spatial relationship between islets and blood vessels has revealed that the majority of islets had no association with arterioles. Islets with a direct contact with an arteriole are significantly larger, a pattern that has been observed throughout the examined mammalian species: human, monkey, pig, rabbit, ferret, and mouse. We hypothesize that the arterioles emerge to feed the bulk exocrine pancreas regionally with no preferential targeting of individual islets. Vascularizing the pancreas in this way may allow an entire downstream region of islets and acinar cells to be simultaneously exposed to changes in the blood levels of nutrients, hormones digestive enzymes and other circulating factors, which could underlie the pathogenesis of pancreatic diseases including diabetes. In this application, this hypothesis will be tested by modeling the pancreas blood flow crosstalk using in vivo models (Aim 1). In parallel, the characteristics of the human pancreatic vascular network will be examined using our unique collection of the whole human pancreata (currently n>210 spanning the lifetime from 7-days to 85 years of age) and specimens from the Network for Pancreatic Organ Donors with Diabetes (nPOD) (Aim 2). In this multi-disciplinary proposal, we have assembled complementary expertise that widely cover all necessarily research fields to accomplish the propose projects: endocrine and exocrine microcirculation, advanced animal surgery, vascular biology, endocrinology, diabetes, beta-cell/islet physiology and biology, genetics, pathology, gastroenterology, pancreatitis and pancreatic cancer, allogeneic and autologous islet transplantation, and immunology.

NIH Research Projects · FY 2026 · 2024-01

PROJECT SUMMARY Normal coronary artery formation is essential for heart growth and function. Malformed coronary arteries are a clinically significant birth defect that can cause life-threatening cardiac complications, including ventricular noncompaction, myocardial ischemia, and sudden cardiac death. Yet, developmental mechanisms that drive proper coronary artery formation are incompletely understood, which has hindered our ability to develop the heart-specific interventions for this devastating disease. The long-term goal of this project is therefore to reveal the molecular and cellular mechanisms underlying coronary artery development so that we may identify key regulatory factors for developing new targeted therapies to combat this congenital condition. We have addressed this goal during previous finding period. Our studies have shown that embryonic coronary arteries in the inner compact myocardium are formed by ventricular endocardial cells through angiogenesis regulated by the VEGF- NOTCH signaling. Furthermore, our studies have revealed that these embryonic coronary arteries undergo angiogenic expansion perinatally to add the neovessels to the growing compact myocardium. However, in contrast to the vascularization of the compact myocardium, we know little about vascularization of trabecular myocardium which remains largely avascular until birth. We have recently identified a subpopulation of coronary progenitor cells among ventricular endocardial cells which are committed to the coronary arteries in the trabecular myocardium. We named these cells as the second wave coronary progenitors (SCPs) to separate them from the first wave coronary progenitors (FCPs) for the coronary vessels at the compact myocardium. SCPs acquire angiogenic potential earlier in embryonic development through a previously unknown endocardial to mesenchymal transformation (EMT) long before they undergo angiogenesis later during perinatal periods to vascularize the trabecular myocardium. In this renewal application, we propose to characterize this new angiogenic-EMT paradigm (angioEMT) by SCPs. Our overarching hypothesis is that vascularization of trabecular myocardium by SCPs is regulated by a “two-hit” mechanism involving sequential angioEMT and hypoxia signaling. We plan to test this hypothesis in three Specific Aims. Aim 1 will characterize SCPs by distinguishing them from FCPs using a lineage-based single cell RNA-sequencing (scRNA-seq) analysis and a modified functional angioEMT assay. Aim 2 will define the angioEMT signaling in the early fate decision by SCPs using genetic loss-of-function approaches investigating the TGFb signaling. Aim 3 will decipher the angiogenic signaling in the later angiogenic activation of SCPs focusing on VEGFA-VEGFR3 and DLL4-NOTCH1 signaling. Vascularization of trabecular myocardium as well as trabecular compaction in the individual nulls will be examined by histology, immunostaining, and RNAscope in situ hybridization. The changes in the SCP lineages will be determined by scRNA-seq analysis, whereas the key factors underlying the two-hit angioEMT process will be identified through gene network analysis. By completing these aims, we expect to provide new mechanistic insights into coronary artery development that inform developmental pathogenesis of coronary artery anomalies and ventricular noncompaction.

NIH Research Projects · FY 2025 · 2024-01

Project Summary Background: High-deductible health insurance plans, which are characterized by low premiums coupled with substantial costs for accessing medical services, are one of the most common tools for containing growing health spending in the United States. Currently, nearly one-third of U.S. adults with employment-based health insurance coverage—some 50 million people—have a deductible higher than $2000. In line with theoretical predictions and intended policy goals, robust evidence shows high-deductible health plans reduce spending by reducing medical service use. Yet, questions remain about whether these reductions come at the expense of care valuable for patient health. These concerns are especially acute for low-income enrollees who are at greater risk for chronic conditions. As high-deductible health plans continue to proliferate in the United States, actionable information is needed about their impact on use of clinically valuable health care services and whether high-deductible plans exacerbate existing income-related disparities healthcare utilization. Objective: This project will assess the effect of high-deductible health plan enrollment on medical service utilization and spending and how the effect varies across household income. Methods: I use a quasi-experimental research design known as a difference-in-differences analysis to measure outcomes among individuals before and after high-deductible plan enrollment relative to a comparison group whose health insurance does not change. To mitigate bias caused by individual selection into plans, I analyze the subset of individuals who enroll due to an employer-mandated switch. I perform the analysis on a large individual-level dataset that contains detailed medical and pharmaceutical claims information for approximately 3.1 million people with employment-based insurance who lived in a U.S. state from 2015 to 2019. Unlike most claims datasets, the data link individuals to their census block group of residence, a precise geographic identifier that can be merged with publicly available income data at the same level of detail. I measure overall spending and utilization and then focus on specific bundles of services shown to be clinically valuable for preventing or treating disease or, conversely, to have little to no value in maintaining health, so-called low-value care. I compare results on these outcomes by income using quintiles of the observed income distribution. Impact: The analysis will generate policy relevant and readily translatable estimates of the effects of high- deductible plans on health service use, including use of valuable versus low-value care, and allow for comparison of differences across income. This project will help policymakers and public health experts better target interventions to mitigate potential negative effects of high-deductible plans on valuable service utilization and inform the current debate about the role of health insurance in health disparities.

NIH Research Projects · FY 2026 · 2024-01

PROJECT ABSTRACT There is a massive prevalence of diabetes in the U.S. with 34.2 million having diabetes, and 88 million adults with prediabetes. Type 1 diabetes results from the autoimmune destruction of the islet β cell mediated in part by β-cell dysfunction prior to autoimmune attack. Polyamine and hypusine production are important for the translation of a subset of RNAs involved in the unfolded protein response, ER stress, and cytokine response in the β cell. Our preliminary data suggests that the polyamine/hypusine pathway is involved in the translation of proteins required for the response of the β cell to inflammation. Inhibition of two rate limiting enzymes along the polyamine/hypusine pathway, either genetically or with small molecule inhibitors, results in a decrease of ER stress leading to protection from β-cell death and ultimately type 1 diabetes. For this proposal we will use a combination of mouse, and human models to understand how the polyamines and hypusine specifically alter the β cell’s response to stress. We propose to study the role of polyamines and hypusine in specific mRNA translation of proteins that are important to the maladaptive response of β-cell ER stress and hypothesis that polyamine depletion leads to ER stress resolution, preserved β-cell function, and ultimately reduced T1D pathogenesis. To test this hypothesis, we propose the following aims: Aim 1: Interrogate the molecular mechanisms by which the polyamine/hypusine pathway contributes to β-cell dysfunction and death. Aim 2: Determine the role of β cell polyamine/hypusine pathway during autoimmunity and the development of T1D. Aim 3: Assess the efficacy of treatment with polyamine/hypusine blockade. The primary impact of this proposal is the identification of mechanisms of the polyamine/hypusine pathway in β cells during the diabetes pathogenesis.

NIH Research Projects · FY 2026 · 2024-01

PROJECT SUMMARY / ABSTRACT All animal behaviors and cognition require precise assembly of neural circuits. Despite a highly complex environment in the central nervous system, neurons faithfully recognize their precise partners and establish synaptic connections. Precise connectivity has been well demonstrated across many organisms, but the mechanisms underlying this specificity remain unclear. Cell surfaces proteins (CSPs) have been implicated in establishing correct connectivity, specifically by serving as “identification tags”. In Drosophila, two CSP subfamilies of the immunoglobulin superfamily (IgSF), the Dprs and DIPs, have garnered significant attention due to their multifaceted roles in nervous system development. The 32 members of the Dpr and DIP subfamilies are GPI-anchored, and several interacting pairs were demonstrated to have roles in instructing connectivity in several circuits. For example, DIP-α is required for instructing connectivity between motor neurons (MNs) and muscles in the motor system and between interneurons (INs) in the visual circuit. Our preliminary data suggests that DIP-α localizes to the dendrites of MNs as well, suggesting a potential role in IN-MN recognition. Despite their fundamental roles in various circuits, the signaling mechanism(s) underlying DIP/Dpr functions remains unclear. This proposal will test two non-mutually exclusive hypotheses: Aim 1) DIPs and Dprs instruct IN-MN connectivity and Aim 2) DIPs and Dprs interact with other CSP co-receptors to transduce cellular signals. I will focus on DIP-α because of its implications in connectivity, cell survival, and synaptic development; however, I hypothesize that some signaling components will be shared between Dpr/DIP members. In Aim 1, I will reconstruct MN dendrite morphology and synaptic connectivity between a MN and its presynaptic INs. I will determine if known DIP-α interactors, Dpr6/10, are required and investigate the functional outcome of disrupting DIP-α-dependent connectivity. In Aim 2, I will use proximity labeling to uncover candidate DIP-α co-receptors in an unbiased manner, and I will validate them biochemically and genetically. This proposal will combine interdisciplinary and innovative approaches, including optogenetics, electrophysiology, biochemistry, microscopy, proteomics, and bioinformatics to elucidate fundamental mechanisms underlying synaptic connectivity. The proposed work will address significant knowledge gaps in central motor circuit connectivity and signaling mechanisms of GPI-anchored proteins. The vertebrate orthologs of DIPs/Dprs, the IgLONs, are also GPI-anchored and are associated with various diseases, including Alzheimer’s disease and autism spectrum disorder. Thus, our proposed study may also contribute to our understanding of the molecular processes disrupted in specific neurological disorders.

NIH Research Projects · FY 2026 · 2024-01

PROJECT SUMMARY The treatments for various squamous cell carcinomas (SCCs), such as SCCs of the head and neck, have been revolutionized by the development of immunotherapies. However, even though many treated patients can evoke robust initial responses, most SCC patients often experience rapid tumor relapse, the nature of which is still poorly understood. Such hurdles highlight the dire need to uncover novel mechanisms driving immunotherapy resistance. Understanding tumor relapse after immunotherapy will be vital for advancing clinical outcomes. Thus, the broad research objective of this proposal is to understand the molecular network driving tumor relapse from cancer immunotherapy. Cancer immune evasion is a highly complex process mediated by both an immune suppressive microenvironment and cancer cell-intrinsic resistance mechanisms. Recently, in a genetically engineered mouse model of SCC, we revealed a group of TGFβ-responding tumor- initiating cells (TICs) that hijack many molecular features of adult tissue stem cells. Importantly, these cells appear to be the root of tumor relapse after immunotherapy treatment and are endowed with unique programs that facilitate their remarkable immune resistance. This key finding raised the importance of identifying the critical molecular features for these TICs in driving immune resistance in SCCs. In this study, we identified the pivotal roles of Sox2 as the master transcription factor in orchestrating the TIC-specific immune resistance program. Here, we will employ an ultrasound-guided in utero lentiviral gene delivery approach to achieve rapid genetic manipulation of TICs directly in spontaneous SCC tumors. With this powerful technique, we aim to first identify the Sox2-activated transcriptional network for shaping the immune suppressive microenvironment. Second, we will dissect the mechanisms of how Sox2 enhances the intrinsic immune resistance of tumor- initiating cells. Collectively, our proposed study will advance our understanding of the immune resistance mechanisms specific to TICs and how these mechanisms promote SCC relapse after immunotherapy treatment. Ultimately, defining the blueprints of the TIC-specific immune evasive mechanisms will open new avenues to overcome the SCCs recurrence and improve the efficacy of current cancer treatments.

NIH Research Projects · FY 2026 · 2023-12

Project Summary Identifying risk variants and genes of immune diseases will not only improve our understanding of these diseases, but also point to potential therapeutic targets. Genome-wide association studies (GWAS) are commonly used to study complex diseases, and have been highly successful in a range of disorders, for instance, more than 200 loci have been associated with the risk of asthma. Nevertheless, to translate these associations to mechanistic understanding has been difficult, largely because most of the trait-associated variants are located in noncoding regions with unknown functions. Current work has often been focused on the variants in enhancer regions that may affect gene expression, yet growing evidence suggest that other mechanisms, particularly those regulate RNA processing, may also be important. The goal of this project is to improve our understanding of functions of genetic variants by studying their effects on N6-methyladenosine modification (m6A) of RNA molecules. M6A modification is a relatively new, yet important mechanism of regulating RNA processing, including splicing, degradation, intracellular transport and translation. Despite the widely accepted function of m6A at the molecular level, its contribution to genetics of human disorders is largely unknown. Our recent work on m6A-modifying variants, called m6A-QTLs, in a human B cell line, show shat these m6A-QTLs are enriched with GWAS-detected variants of immune-related traits, and their effects are largely independent of those variants acting on gene expression or splicing, representing a novel path from genetic to phenotypic variations. We propose to extend this work in several directions. (1) We will map m6A-QTLs on mRNAs in several major immune cell types (B, CD4 and CD8 T, NK and monocytes) from human blood, in both resting and immune-stimulated conditions. This study will map many cell-type and response-specific m6A-QTLs that would be missed in a single cell type or condition. (2) We will integrate these resources with GWAS data to identify specific m6A sites and genes that may play important roles in immune phenotypes. This analysis will employ a novel statistical method that improves the power of detecting m6A sites and genes with causal effects. (3) A recently discovered role of m6A is regulation of chromatin-associated RNAs, especially those with regulatory functions (carRNAs), such as enhancer RNAs and repeat-derived RNAs. We will also identify m6A-QTLs of these carRNAs in human T cells, and study their contribution to human immune phenotypes.

NIH Research Projects · FY 2026 · 2023-12

PROJECT SUMMARY When we interact with objects using our hands, we are able to easily distinguish between our keys and our phone, and can do so even without visual cues. This ability to sense the three-dimensional structure of an object through haptic exploration alone is termed stereognosis and relies on the integration of two distinct streams of sensory information: tactile signals from the fingertips contacting the object relay information about local features (e.g., edge location, curvature, texture), and proprioceptive information from the muscles relay information about the overall shape and size of the object. While the integration of tactile and proprioceptive signals has been observed at higher order stages of somatosensory processing (Brodmann’s area 2, secondary somatosensory cortex, parietal ventral area), the neural mechanisms underlying this integration remain largely unknown. Given that the hand is a highly deformable sensory sheet, there are likely unknown neural processing mechanisms unique to the somatosensory system that underlie this integration process and a new framework will be necessary to understand how stereognosis can arise. The goal of the present study is to better understand the principles of multimodal integration that give rise to stereognosis by characterizing the responses of multimodal neurons in area 2 during grasping (Aim 1) and by developing computational models of how tactile and proprioceptive signals are integrated to give rise to object representations that are independent of how objects are grasped (Aim 2). We anticipate that the computational models will inform the interpretation of our neurophysiological results and deep novel insights into the neural mechanisms of stereognosis. Not only will the results of the study contribute to basic science, but they will also have implications for translational research and clinical applications. Our study of neural coding along the primate neuraxis informs our work toward more dexterous brain-controlled prostheses, which involves inferring motor intent but also restoring sensory feedback. Indeed, our ability to dexterously interact with objects, even without vision, depends on neural representations of objects. We anticipate that a deeper understanding of object representations in higher order somatosensory cortices, including area 2, will allow us to leverage these representations to improve the informativeness of intracortical microstimulation-based somatosensory feedback, thereby conferring greater dexterity to the brain-controlled bionic hands.

NIH Research Projects · FY 2025 · 2023-12

Project Summary Recent clinical trials of platelet-inhibiting medications for preventing a second stroke following an initial minor stroke or transient ischemic attack (TIA) have shown that recurrences of strokes over time follow a distinct time course, with a high rate of recurrence over the first few days, slowing to a steady lower rate over subsequent months. We have shown that this temporal course can be predicted from a model of stroke recurrence risk based on kinetic analysis, in which rates of events are proportional to numbers of subjects in a given state multiplied by a fixed kinetic rate for that state. A kinetic model that postulates both a transient vulnerable state and a stabilized state following initial ischemic events predicts a specific mathematical form for the time course of the event-free survival curve (the proportion of subjects not yet having experienced a recurrence, over time). The predictions of this model closely match the data from the POINT, SOCRATES, and THALES trials, and allow for estimation of the kinetic rate constants that describe the rate of ischemic stroke recurrence in the vulnerable state (k1), the rate in the stabilized state (k2), and also the rate of transition from the vulnerable to stabilized state (k0).These different rates that determine risks of stroke recurrence are likely to relate to different underlying biological mechanisms, and to be distinct in their responses to different treatments. In fact, we have shown that the added anti-platelet medication strategies used in these trials only affected only k1, not the other rates. Understanding the condition of patients following stroke in these kinetic terms of distinct vulnerable and stabilized states, subject to different biologically-determined rates of stroke recurrence, allows for exploring what patient risk factors or treatments may selectively affect the different rates. These insights have implications for how clinical trials of treatments should be designed. For instance, if a certain type of treatment only affects k1, the rate of stroke recurrence in the transient vulnerable state, then it is only likely to make an impact when applied rapidly and for the short-term following the initial stroke. In contrast, interventions affecting the recurrence rate in the stabilized state will need to be applied for longer periods to impact overall stroke recurrence. Determining the distinct effects of risk factors or treatments on the individual rate constants requires data from large numbers of patients to quantify the effects. By combining the data from the large SOCRATES, POINT, and THALES trials into a unified and harmonized data set, these types of careful analyses can be performed, testing important questions as to which kinetic rates are specifically affected by patient risk characteristics, by treatments such as cholesterol-lowering medicines or anti-inflammatory medicines, or by the presence of significant plaque and stenosis in intracranial arteries. These important insights, with implications for the design of future clinical trials, are the goal of this project.

NIH Research Projects · FY 2026 · 2023-12

Project Summary Recent clinical trials of platelet-inhibiting medications for preventing a second stroke following an initial minor stroke or transient ischemic attack (TIA) have shown that recurrences of strokes over time follow a distinct time course, with a high rate of recurrence over the first few days, slowing to a steady lower rate over subsequent months. We have shown that this temporal course can be predicted from a model of stroke recurrence risk based on kinetic analysis, in which rates of events are proportional to numbers of subjects in a given state multiplied by a fixed kinetic rate for that state. A kinetic model that postulates both a transient vulnerable state and a stabilized state following initial ischemic events predicts a specific mathematical form for the time course of the event-free survival curve (the proportion of subjects not yet having experienced a recurrence, over time). The predictions of this model closely match the data from the POINT, SOCRATES, and THALES trials, and allow for estimation of the kinetic rate constants that describe the rate of ischemic stroke recurrence in the vulnerable state (k1), the rate in the stabilized state (k2), and also the rate of transition from the vulnerable to stabilized state (k0).These different rates that determine risks of stroke recurrence are likely to relate to different underlying biological mechanisms, and to be distinct in their responses to different treatments. In fact, we have shown that the added anti-platelet medication strategies used in these trials only affected only k1, not the other rates. Understanding the condition of patients following stroke in these kinetic terms of distinct vulnerable and stabilized states, subject to different biologically-determined rates of stroke recurrence, allows for exploring what patient risk factors or treatments may selectively affect the different rates. These insights have implications for how clinical trials of treatments should be designed. For instance, if a certain type of treatment only affects k1, the rate of stroke recurrence in the transient vulnerable state, then it is only likely to make an impact when applied rapidly and for the short-term following the initial stroke. In contrast, interventions affecting the recurrence rate in the stabilized state will need to be applied for longer periods to impact overall stroke recurrence. Determining the distinct effects of risk factors or treatments on the individual rate constants requires data from large numbers of patients to quantify the effects. By combining the data from the large SOCRATES, POINT, and THALES trials into a unified and harmonized data set, these types of careful analyses can be performed, testing important questions as to which kinetic rates are specifically affected by patient risk characteristics, by treatments such as cholesterol-lowering medicines or anti-inflammatory medicines, or by the presence of significant plaque and stenosis in intracranial arteries. These important insights, with implications for the design of future clinical trials, are the goal of this project.

NIH Research Projects · FY 2025 · 2023-11

PROJECT SUMMARY: The high rates and upward trend of mental health (MH) problems among young Asian Americans (AAs) are disturbing. Despite mounting evidence of MH crisis, AAs are severely understudied, exacerbating health disparities. Spikes in sociopolitical tensions and racial hostility in recent years may explain the upsurge of the problems. Young AAs are under great acculturative as well as minority stress, including being the frequent victims of hate crimes, experiencing harmful objectification by the majority and other minority groups, and having their American identities questioned. This stressful environment has been aggravated by the COVID-19 pandemic, which has provoked an unprecedented surge in anti-Asian racism and bigotry. There is a particularly pressing need for young AAs to identify ways to navigate these multifold pressures. This proposed study will extend an existing, highly successful longitudinal study of young AAs. The Midwest Longitudinal Study of Asian American Families (MLSAAF) is an ongoing survey of Filipino American (FA) and Korean American (KA) families (786 youth and their parents; MAGE of youth = 15 at Wave 1 in 2014). Wave 4 in 2021 collected data from 615 young adults (YAs) (MAGE=21.5; 78% retention). The MLSAAF has substantiated a troubling upward trend in MH struggles from 2014 to 2021 as participants transitioned to early young adulthood (YAH). We also uncovered racial discrimination and intergenerational cultural conflict (ICC) in the family as the etiology of this upsurge of problems. Minority and acculturative stresses are expected to amplify as YAs build careers and families of their own. AA families remain interdependent during YAH, with unwavering expectations of familism, conceivably prolonging ICC among AA YAs. By adding 3 waves, the proposed study will leverage the rich and rare MLSAAF data to follow the original samples from adolescence (ADOL) into their twenties to disentangle the complex and dynamic effects of family process, minority stress, and acculturation across the critical stages of YAH, including such pivotal outcomes as education, employment, marriage, and parenthood. Biomarkers (cortisol, C-reactive protein, and sleep) are added to investigate physiological damage of chronic stress from racial/cultural minority status. The inclusion of biomarkers will significantly enhance our capacity to more accurately assess biological, physical, and psychological harms of chronic stress that individuals may be unaware of. This study will (1) determine the trajectory and etiology of MH and physical health among young AAs as they transition from early ADOL to YAH. We will test (a) how AA family process (e.g., harmful vs. beneficial practices) is concurrently and longitudinally associated with ICC and the MH/health outcomes and (b) how racial discriminations are concurrently and longitudinally associated with poor outcomes, (2) investigate how bicultural competence mitigates the negativity of chronic psychosocial stressors (i.e., ICC and discrimination) and (3) to examine the associations in Aims 1 and 2 with biomarkers as outcome measures and to identify harms of chronic stress that self-report measures may not capture.

NIH Research Projects · FY 2024 · 2023-09

PROJECT SUMMARY Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer type in urgent need of more effective treatment options. A notable feature of PDAC tumors is the highly altered nutrient conditions present within the tumor microenvironment (TME) caused by poor perfusion from the supporting tumor vasculature. Although PDAC cells can rapidly proliferate within these suboptimal nutrient conditions, the metabolic adaptations they rely upon to do so remain unknown. Furthermore, understanding these adaptations has the potential to reveal therapeutically targetable vulnerabilities of PDAC cells in vivo. Towards this end, we have developed a novel medium formulation (TIFM) that recapitulates the nutrient conditions present within PDAC tumors in vivo, in order to study the metabolic responses of PDAC cells to tumor nutrient stress using tractable ex vivo models. Applying pooled CRISPR-interference (CRISPRi) screening to this new model system, we surprisingly identified a hypoxia-induced kinase, pyruvate-dehydrogenase kinase 1 (PDK1), as being critical to the fitness of PDAC cells in TIFM, even under normoxia conditions. PDK1 is a kinase normally activated by hypoxia to inhibit the pyruvate dehydrogenase (PDH) complex and thus redirect pyruvate-derived carbon away from the TCA cycle and towards lactic acid fermentation. The overall goal of this proposal is to understand how and why PDK1 and aerobic glycolysis become critical to PDAC cellular fitness during tumor nutrient stress, and to evaluate in vivo the functional dependence of PDAC cells on suppressed pyruvate oxidation for tumor growth. I hypothesize that two potential mechanisms may underlie PDK1 dependency in TIFM: (1) PDK1 promotes aerobic glycolysis to prevent the production of cytotoxic levels of reactive oxygen species (ROS) or (2) supports NAD+/NADH cofactor balance for macromolecule biosynthesis. Further, I hypothesize that PDK1 activity is upregulated under TIFM conditions through a nutrient-sensitive mTORC2-AKT-PDK1 signaling axis. We will investigate this hypothesis in three specific aims. Aim 1. Functional and metabolic assays will be performed to determine the adaptive function of PDK1 under tumor nutrient stress. Aim 2. Functional and biochemical assays will be performed to identify the nutrient factor in TIFM responsible for PDK1 dependency and elucidate the signaling pathway that communicates its availability to the TCA cycle. Aim 3. Animal studies will be performed to determine the essentiality of suppressed pyruvate oxidation for PDAC tumor growth in vivo. These findings reveal a critical metabolic dependency of cancer cells in adaptation to the nutrient stress present in the TME. Furthermore, understanding this adaptation may reveal novel therapeutic strategies for managing pancreatic cancer in the clinic based on metabolic constraints set by the tumor microenvironment.