University Of California At Davis

NIH Research Projects · FY 2025 · 2024-07

PROJECT SUMMARY: Our overarching goal is to develop a transformative integrative clinical, experimental and in silico-based pipeline to create a digital twin technology for patient-specific prediction. Digital twin technology holds the promise of the development and application of virtual models that replicate physiological processes and characteristics of diseases to reveal mechanisms, simulate disease progression, identify potential drug targets and simultaneously predict drug efficacy. While our planned approach is broadly applicable, here we will apply digital twins to the problem of identification of cardiac drug targets and prediction of the efficacy or cardiotoxicity of drugs in individuals. A major strength of our digital twin approach is that it incorporates data from the atomic structure to the cardiac rhythm, allowing the inclusion of individual differences that affect individual protein structure, cellular electrophysiology and electrocardiograms. Digital twins will allow for improved understanding of how variation between individuals modifies disease severity and drug cardiotoxicity risks. Such a technology is possible now due to the maturity of deep-learning based modeling and simulation approaches in conjunction with the increasing availability of ion channel protein structures in physiologically relevant states, and the development of patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Combining these developments will allow for the realization of high throughput testing for individuals to determine their disease- and drug-related risks. Indeed, our preliminary data indicate the promise of a new deep learning method to extract in silico representations of individual cellular electrophysiology and Ca2+ handling to digitally replicate the mechanistic cellular fingerprint. We will build a new digital twin framework across multiple system scales by bringing together new methods in atomistic scale simulation with recently developed cellular level models and deep learning networks to discover new protocols to extract needed model parameters from data and for translating from iPSC-CM to adult cardiac myocyte electrophysiology. We will develop and test an experimental and computational digital twin platform applied to problem of personal cardiac disease expression and drug-induced cardiotoxicity via a combined computational-experimental approach that will allow the construction, prediction and validation of patient-specific digital twin cardiac cells. We aim to 1) Develop cardiac ion channel protein digital twins for structure and function prediction, 2) Develop cardiac myocyte digital twins, and 3) Predict the patient-specific cardiac safety pharmacology of individual drugs and combined therapeutics. We are bringing together model simulations at the level of the atom in a totally new way to include genetic mutations spanning benign variants to ones with known arrhythmia risks (from which all other models can be developed by extension) and predict their impact on drug interactions and biological function modulations at different scales. The proposed studies have the potential to conceptually transform the field by generating an integrative, high-throughput framework that predicts individual responses to disease and drugs.

NIH Research Projects · FY 2026 · 2024-06

Project Summary: The nexus between diet, microbiome, and host involves molecular signals and xenometabolites (“non- self” molecules derived from microbial metabolism) that remain largely unmapped. DNA and RNA sequencing technologies have led to major advancements in understanding how abundances of specific gut microbes correlate to health, diet, and disease; however, the most important information about microbe-host and microbe-microbe communication will emerge from greater understanding of functional outcomes including microbial xenometabolism. To address this knowledge gap, the current proposal will leverage the diversity of innovative human gut bacterial cultures to expand the catalog of microbial metabolites, which can be screened to characterize binding and bioactivity characteristics relevant to physiology and health. This approach is a direct response to guidance from PAR-21-253, Identification and Characterization of Bioactive Microbial Metabolites for Advancing Research on Microbe-Diet-Host Interactions. Considering the paucity of information related to microbial fat metabolites in particular, our primary focus will be on xenolipid discovery, including (but not limited to) characterization of cyclopropane fatty acids (CpFAs) as an illustrative example of discovery-to-bioactivity proof-of-principle. For instance, the extant literature and our preliminary results indicate that novel odd-chain CpFAs are generated by bacteria harboring CpFA synthase (cfa), with CpFA catabolized by hepato-splanchnic tissues, stored, and released by white adipose tissue. Our data support anti-inflammatory effects of some CpFAs, as well as binding of peroxisome proliferator activated receptors (PPARs). The team will leverage human gut microbes cultured with combinations of fiber/complex carbohydrate substrates with or without diet-relevant fats, to drive substrate-specific bacterial communities and associated xenometabolomes. We will—for the first time—comprehensively identify xenolipids and non-lipid metabolite patterns that track the fiber and fatty acid milieu, and that correlate with specific bacterial communities varying in phylogeny. This will expand the library of microbe metabolites and shed light on how dietary components such as fibers and lipids interact to alter the xenometabolome. A complementary aim to interrogate the effects of xenolipids on nuclear receptors, inflammation and GPCR read-outs, and broader effects in gut organoids will link our findings to potential bioactivities, one of the remits of PAR-21-253.

NIH Research Projects · FY 2026 · 2024-06

Project Summary Most, if not all, cognitive functions require the coordination of multiple brain regions. The ability to simultaneously monitor neural activity across multiple brain regions in cellular resolution and high speed during natural behavior is important to study how different parts of the brain work together to support behavior. Doing so requires the recording device to have a high spatiotemporal resolution over a large field of view, and be sufficiently light and compact so it can remain stable on the animal’s head while the animal freely behaves. Optical methods are especially promising to fulfill all these requirements. However, existing optical miniaturized microscopes have tradeoffs among the field of view, resolution, and device footprint. To achieve fine resolutions, most of the existing miniaturized microscopes can only image a sub-millimeter scale field of view. We propose to develop a miniaturized imager that can record neuronal activity in near-cellular resolution over the entire cranium in freely-behaving mice. We have previously demonstrated a miniaturized 3D microscope where all bulk lenses are replaced by a thin layer of microlens array. The microlens array effectively splits the entire field of view into different regions, and uses different lens units to image them in parallel. A computational algorithm is then used to reconstruct and synthesize the 3D volume. This approach enables high-resolution imaging over a large 3D volume through a thin device. Our microscope achieved <10 µm lateral resolution over 4x6 mm2 field of view, and can reconstruct 3D volume across ~600 µm depth range with ~50 µm axial resolution from a single 2D captured image. In this project, we will optimize and expand the microlens array so it could image neural activity across the entire cranium (~9x10 mm2) and 400 µm depth in near-cellular resolution in freely-behaving mice. We will package the image sensor, microlens array, and illumination optics into a compact device. We will develop deep-learning-based algorithms that can faithfully reconstruct neuronal activity over the 3D cortical volume from recordings that are highly corrupted by light scattering in real time. Compared to existing algorithms, our approach can significantly reduce the required computational resources and processing time. Our miniaturized imager enables the investigation of very large-scale neuronal circuits distributed across the cortex. We will run testbed experiments on both freely-moving mice and head-unrestrained macaque monkeys, two important animal models for studying the neural basis of behavior. We will leverage well-established experimental paradigms, including passive viewing of visual stimuli and navigation in open arenas. These experiments will serve to validate, benchmark, and further refine our techniques in vivo. The cross-species experiments will not only prove the potential of our imager, but also provide critical insights into how animal behavior emerges from the orchestration of individual neurons in large-scale neural circuits. This development and validation of this new technology will pave the way for many exciting future experiments, and greatly enhance our ability to address important neuroscience questions that are challenging with the existing techniques.

NIH Research Projects · FY 2024 · 2024-06

Project Summary The brain is composed of unique cell types, such as neurons and astrocytes, that actively coordinate to enable higher order functions including learning, memory, and cognition. Even slight deviances in the molecular or cellular states of the brain can result in debilitating neurological symptoms whose severity, treatment course, and overall treatment outcome vary widely from patient to patient. This level of complexity likely contributes to promising therapeutics failing within clinical trials and, thus, requires further exploration. To date, most of our foundational knowledge of neuroscience stems from a neuron-centric focus. Recent literature has demonstrated that other cell types, such as astrocytes, may participate in signaling and communication beyond their known passive, supporting roles. As such, exploring the molecular and cellular diversity of astrocytes in their native tissue context will help us better understand neurological function and dysfunction, particularly in Alzheimer’s disease (AD). Because of the inherent spatial and chemical complexity in physiological processes and interconnectedness of cells, we will develop workflows for integrating multiresolution and multimodal imaging methods for the characterization of spatial relationships among cell phenotypes in AD compared to healthy controls. To investigate the molecular diversity within the hippocampus, we are employing a combination of mass spectrometry imaging (MSI) and multiplexed immunofluorescence (MxIF) to gain rich metabolomic information that is associated with cell type and state. MSI can detect hundreds to thousands of endogenous molecules while maintaining their spatial distributions. While chemically informative, these datasets are often difficult to correlate directly to cell type or functional state without an orthogonal technique, such as immunohistochemistry. Because the number of cell types exceed what can be probed by traditional IF approaches within a single experiment, we have chosen to incorporate MxIF, using Cell DIVE, to increase the number of imageable targets compared to traditional fluorescence microscopy. By staining for traditional cell-specific markers, we can use MxIF to connect metabolomic profiles uncovered using MSI to functionally important cellular neighborhoods in AD. Ultimately, we will establish small molecule, lipid, and cellular spatial differences between hippocampal regions of AD and control subjects using high spatial resolution MALDI mass spectrometry imaging (MSI) and highly multiplexed immunofluorescence (MxIF) (aim 1) as well as integrate multimodal data sets to examine the molecular neighborhoods associated with typical and atypical cellular neighborhoods surrounding astrocytes within AD (aim 2). By conclusion of these two aims, we will have developed workflows for integrating MSI and MxIF on the cortex from human AD and control subjects to identify molecular and cellular phenotypes and characterize their spatial relationships within the diseased microenvironment. Ultimately, exploring the cellular and molecular architecture of astrocytes in AD is paramount for understanding this disease and establishing effective therapeutics.

NIH Research Projects · FY 2026 · 2024-06

PROJECT SUMMARY – 30 lines of text Type 1 Diabetes (T1D) is a chronic disease caused by autoimmune destruction of insulin-producing pancreatic beta cells, and there is currently no treatment that reverses the disease. Many T1D reversal approaches have failed in human clinical trials and thus an ongoing and urgent need exists for novel therapies targeting new immune pathways. We have exciting data showing that a TLR4/MD2 agonistic antibody (TLR4-Ab) permanently reversed T1D in 71%, and induced a significant clinical effect in 90%, of acutely diabetic non-obese diabetic (NOD) mice. Recently, we showed that TLR4-Ab can mobilize and activate myeloid-derived suppressor cells (MDSC) that suppress T cells and reverse T1D upon adoptive transfer. We showed that TLR4-Ab remains sequestered in endosomes, unlike the TLR4 agonist LPS (which cannot reverse T1D). However, the mechanism by which TLR4-Ab reverses T1D remains unclear. Herein, we propose mechanistic studies to determine the structural and immune basis of TLR4-Ab reversal of T1D. We have also produced anti-human TLR4 antibodies which will allow us to apply these finding to human T1D.We will achieve this in three aims. Specific Aim 1. Mechanism of T cell suppression and reversal of T1D by TLR4-Ab-induced MDSCs. We hypothesize that TLR4-Ab endosomal sequestration causes sustained endosomal signaling that induces MDSC maturation. We will test this by inhibiting endosomal and surface signaling in myeloid cells while treating with TLR4-Ab and testing effects on MDSC phenotypes, T cell suppression, and ability to reverse T1D. Specific Aim 2. Mechanistic role of Fc structure in TLR4-Ab reversal of T1D and cell suppression. We hypothesize that the IgG3 Fc portion of the TLR4-Ab is critical to its tolerizing function. We will test this by assaying TLR4-Ab F(ab), F(ab)2, and deglycosylated TLR4-Ab in functional assays and on T1D. We will switch the TLR4-Ab Fc from IgG3 to IgG4 subclass to definitively confirm whether IgG3 is required for endosomal sequestration, MDSC formation, T cell suppression and T1D reversal. Specific Aim 3. Characterization of a novel panel of human anti-TLR4 antibodies. We have developed agonistic human recombinant TLR4-Abs (hTLR4-Ab). We show here that these hTLR4-Abs bind TLR4-MD2 and can activate the NF-KB signaling pathway. Our hypothesis is that human TLR4-Ab treatment will induce MDSCs from myeloid cells and that these huMDSCs will suppress human T-cell proliferation and activation. Our studies will characterize a novel innate immune pathway by which TLR4- Ab can reverse acute T1D, and begin to translate these findings to human T1D. This proposal describes a thorough training plan to support my scientific and professional development as an Immunologist.

NIH Research Projects · FY 2025 · 2024-06

PROJECT SUMMARY/ABSTRACT Hemophilia is an x-linked bleeding disorder characterized by deficiencies in clotting factor VIII or IX. Patients suffer from frequent joint bleeding, which may lead to debilitating hemophilic arthropathy (HA). Both symptomatic and silent bleeds, as well as unnoticed microhemorrhages, generate hemosiderin deposits, the primary etiology of joint degeneration in HA. Non-invasive imaging of both hemosiderin and the subsequent damage it causes to cartilage and subchondral bone is important for optimizing costly prophylactic treatment plans and monitoring disease progression. While magnetic resonance imaging (MRI) is the gold standard for evaluation of HA, it has significant limitations including imprecise, only semi-quantitative evaluation of hemosiderin deposition, and an inability to detect both early iron deposition and degeneration in cartilage and subchondral bone. Ultrashort echo time (UTE) MRI sequences, with TEs ~100 times shorter than those of clinical sequences, can overcome these limitations. Using targeted UTE sequences, fast transverse relaxation signals from hemosiderin and the osteochondral junction (OCJ) can be directly detected with high contrast. This study aims to develop a complete package of UTE MRI techniques for evaluation of HA, including 1) accurate quantification of hemosiderin through volumetric mapping of T1, T2*, and susceptibility; 2) assessment of early cartilage damage by monitoring proteoglycan and collagen; and 3) evaluation of the OCJ, and aims to apply this package in cross-sectional and longitudinal studies of three groups of HA patients (mild, moderate, and severe), as well as an age-matched control group. In Aim 1 we will further optimize the speed, contrast, resolution, and accuracy of a series of 3D UTE MRI techniques for morphological and quantitative evaluation of hemosiderin in synovium, and for assessment of articular cartilage health and OCJ changes using a clinical 3T MR scanner. In Aim 2 we will evaluate the optimized 3D UTE and clinical MRI sequences for assessment of hemosiderin, cartilage, and the OCJ in ex vivo tissues from hemophilia patients following total knee arthroplasty (n=10) and from normal cadaveric human knee joints (n=10). We will compare UTE-based morphological and quantitative measures (tissue magnetic susceptibility, T1, T2*, fat fraction, adiabatic-T1ρ, magnetization transfer ratio, macromolecular fraction) with clinical MRI evaluation of hemosiderin, cartilage, and the OCJ, and we will correlate UTE and clinical MRI measures with histopathology, biochemistry, and biomechanics. In Aim 3 we will apply the optimized 3D UTE and clinical MRI techniques to evaluate outcome of prophylaxis in three groups of hemophilia patients with mild (n=20), moderate (n=20), and severe (n=20) HA at two time points (baseline and 12 months), and a group of age-matched healthy volunteers (n=20) once. Cross-sectional and longitudinal UTE and clinical MRI measures will be correlated with Hemophilia Joint Health Scores (HJHSs), Pettersson radiograph scores, and self-reported outcomes. We expect that UTE sequences will be more sensitive to early changes in hemophiliac joints than clinical MRI.

NIH Research Projects · FY 2025 · 2024-06

ABSTRACT: Nontuberculous mycobacteria (NTM) infections such as Mycobacterium abscessus (Mabs) are a growing health concern, particularly in older and immunocompromised patient populations, and are among the most difficult bacterial infections to eradicate. Thus, there remains a critical need to understand the mechanisms enabling Mabs to survive prolonged exposure to lethal antibiotics. The central hypothesis of this proposal is that antibiotic tolerance is a regulated process, controlled by pathways that sense discrete stresses, and transduce signals leading to a coordinated cellular response that mitigates antibiotic cytotoxicity. In our preliminary data we present the results of a Tn-Seq screen to identify genes contributing to antibiotic tolerance. We now propose to use cutting-edge proteomics to study several proteases that were identified in the Tn-Seq screen.

NIH Research Projects · FY 2026 · 2024-06

Enter the text here that is the new abstract information for your application. This section must be no longer than 30 lines of text. Dominance rank is a major determinant of individual success. Dominance rank is gained or lost over the course of repeated social interactions generating hierarchies within groups. These dominance hierarchies are key features of all animal societies. While hierarchies are often stable, predicting an individual’s position within the hierarchy can be very difficult. This is in part because dominance rank can be influenced by numerous factors such as body size, inheritance and perhaps most importantly, previous experience. Considerable evidence highlights how an individual’s current success is strongly determined by their previous success: winners keep winning and losers keep losing. Our understanding of how and why these winner/loser effects occur is still limited, preventing our ability to explain and more importantly, predict why some interactions lead to predictable wins and others lead to upsets in contest outcomes. Here I propose to use a novel framework, Bayesian updating, to describe how individuals respond to dominance interactions throughout their lives. Bayesian updating is a computational mechanism whereby individuals can update their beliefs about the likelihood of a given outcome based on their previous (prior) information and the current information they are receiving. Bayesian updating mimics the inherent path-dependency of changes in dominance rank and offers a longer-term perspective on phenotypic change than current models. Here I will use this framework to make predictions about behavioral, neurological and physiological responses to accumulated contest defeats and successes over the lifetime. I will do this using a novel animal system, the Amazon molly. This naturally clonal vertebrate gives birth to independent offspring providing a unique opportunity to fully isolate the effects of previous experience on behavior, neural activation and hormonal pathways while controlling for genetic and inherited factors that also influence contest success. This work will improve our understanding of how previous experiences can ripple forward to influence current behavior which has implications for our ability to predict responses to behavioral and pharmacological interventions, for pathological or maladaptive behavior (e.g. bullying, PTSD) and can help understand behavioral change throughout the lifetime of individuals.

NIH Research Projects · FY 2025 · 2024-06

PROJECT ABSTRACT The alphavirus Mayaro virus (MAYV) is a mosquito-borne human pathogen that causes febrile illness and arthralgia in Latin America but has not produced widespread outbreaks like related chikungunya virus (CHIKV). MAYV infections probably occur after exposure to infected forest-dwelling vector mosquito species. Previous outbreaks of both CHIKV and Venezuelan equine encephalitis virus (VEEV, another alphavirus) were mediated by viral mutations that confer adaptation to urban-abundant mosquito species, which facilitated forest-to-city spillover promoting urban epidemics. One reason MAYV has not produced widespread epidemics may be that anthropophilic urban Aedes (Ae.) aegypti and Ae. albopictus are incompetent MAYV vectors. Multiple laboratory vector competence studies from different continents show MAYV poorly infects both species where doses required for infection are at the higher end or above human viremia levels. Epidemics could result if MAYV adapts to increase infection and transmission at lower ingested doses in either urban Ae. species since an increase in mosquito susceptibility means that infected people with low viremias are infectious to mosquitoes, which can potentiate mosquito-human-mosquito cycling. In earlier studies, we used serial passaging and sequencing to identify an envelope (E) gene CHIKV mutant know to lower the oral infectious dose and increase transmission by Ae. albopictus. This work demonstrates the power of experimental evolution to retrospectively identify epidemiologically relevant alphavirus mutations. However, similar studies have not been performed for MAYV. The goal of this project is to assess the potential for Mayaro virus to adapt to urban mosquito vectors using an experimental evolution approach. We hypothesize that MAYV can adapt via serial Ae. mosquito and alternating Ae.-mouse-Ae. passage to 1) increase infection of and transmission by Ae. aegypti and Ae. albopictus mosquitoes at lower ingested doses; 2) maintain transmissibility during alternating cycling; and 3) accrue E gene mutations that augment Ae. infection and transmission. These hypotheses will be tested by assessing the potential for MAYV adaptation to and sustained cycling via urban Ae. by (Aim 1A): evaluating fitness of MAYV serially passaged in Ae. aegypti and albopictus mosquitoes, (Aim 1B): evaluating fitness of MAYV alternately passaged between Ae. and mice, and (Aim 1C): identifying mutations that arise during MAYV passage and evaluating mutant fitness in mosquitoes. This project represents the first experimental evolution studies for MAYV in Ae.. Understanding the potential for adaptation is important to define the risk of future MAYV outbreaks mediated by novel vector use. Knowledge of mutations that confer MAYV adaptation to Ae. can be used to define mechanisms of increased mosquito infection and transmission, for inclusion in MAYV vaccine development, and as a target for genomic surveillance. The use of experimental evolution to predict virus adaptation can lead to a paradigm shift to enable proactive measures to prevent virus epidemics.

NIH Research Projects · FY 2026 · 2024-05

ABSTRACT Chronic kidney disease (CKD) is a gradual loss of kidney function, which affects an estimated 37 million American adults, resulting in 14.6 deaths per 100,000 population. Once kidney damage occurs, it impairs removal of uremic toxins, leading to further deterioration of physiological functions and progression of renal failure. Surprisingly, many uremic toxins are not produced by the body itself, but rather derived from the gut microbiota. CKD is associated with changes in the composition of the gut microbiota (dysbiosis), which is characterized by an increased abundance of Enterobacteriaceae in the fecal microbiota, a group of microbes known to produce uremic toxins, such as indole. The objectives of this application are to understand the ecological causes of dysbiosis in CKD on a molecular level and to determine whether dysbiosis has a causative effect on CKD progression. Our central hypothesis is that elevated expression of inducible nitric oxide synthase (iNOS) in the intestine fuels growth of Enterobacteriaceae by anaerobic nitrate respiration. In turn, increased indole production by respiring Enterobacteriaceae aggravates CKD disease progression. We will test different aspects of our hypothesis using the logical and innovative approach outlined in the following specific aims. Specific Aim 1: Determine the ecological causes of dysbiosis during CKD. Specific Aim 2: Determine whether dysbiosis has a causative effect on CKD progression. The proposed work is innovative because it is among the first to provide molecular insights into how changes in the microbiota composition occur in CKD, and how microbiota changes are causatively linked to disease progression. Successful completion of the proposed work will establish how CKD-associated host responses drive changes in the ecology of the gut microbiota, which in turn set the stage for release of uremic toxins by Enterobacteriaceae, thus accelerating CKD progression. This outcome will be of broad significance for the rational design of new intervention strategies.

NIH Research Projects · FY 2026 · 2024-05

Multiple-X-ray Source Array-based Computed Tomography (MXA-CT) The long-term objectives of the proposed research are to develop an x-ray tube which contains an array of 6 x- ray sources within the same vacuum enclosure, and then demonstrate the utility of this multiple x -ray source array (MXA) towards improving image quality in whole body (general-purpose) computed tomography (CT) scanners as well as cone beam CT systems. Current CT systems with a single x-ray source which have large coverage along the length of the patient (the z-axis) suffer from considerable cone beam artifacts at the peripheral edges of the field-of-view, due to incomplete sampling caused by angled x-ray trajectories imposed by the geometry of a single x-ray source system. By aligning six x-ray sources along the z-axis and pulsing them wisely during the CT scan, the angled x-ray trajectories which cause cone beam artifacts can be significantly reduced, essentially eliminating these cone beam artifacts. The specific aims include (1) design, fabrication and testing of the six-source x-ray tube, (2) design and construction of a test bed tabletop CT scanner which will use the MXA source to demonstrate the superior performance of the proposed scanner system as a proof -of- principle, (3) work in collaboration with one of the largest manufacturers of x-ray tubes in the world (Varex) to gain from their x-ray tube (and detector) experience and demonstrate with them the scientific and technical potential of this new x-ray tube design in a way that facilitates commercialization of the MXA-CT technology, (4) development of CT image reconstruction algorithms (including conventional and AI-based) which are specifically tailored to the unique geometry of the proposed tabletop CT prototype, (5) perform Monte Carlo and other computer simulations to thoroughly evaluate the radiation dose distribution produced by this new sca nner geometry, and (6) use phantom and cadaver imaging experiments on the prototype MXA-CT system to demonstrate superior CT imaging performance using rigorous quantitative metrics of image quality and artifact reduction. This proposal is submitted under the Bioengineering Partnerships with Industry (BPI, PAR-22-123), and represents a collaboration between University of California Davis, Johns Hopkins University, University of New Mexico Albuquerque, and Varex Imaging as our corporate partner. Along with t hree engaged consultants, the research team possesses depth and breadth with respect to CT imaging and technology development, along with established track records of collaboration between the members of the team .

NIH Research Projects · FY 2025 · 2024-05

Project Summary/Abstract People living with HIV (PLWH) are at increased risk of developing HIV-related lymphoma, are less likely to receive cancer treatments such as chemotherapy and radiotherapy, and the likelihood of receiving a curative treatment such as hematopoietic cell transplant (HCT) for HIV-related lymphoma is unknown. There are no definitive guidelines for HCT use in HIV-related lymphoma, despite studies demonstrating equivalent overall survival between those with and without HIV. Current evidence is limited by small samples or single-center studies conducted with highly specialized infectious disease teams. Clinical challenges unique to HIV include added risks for infections and hospitalizations, and drug-drug interactions between antiretrovirals and chemotherapy, contributing to the lack of HCT adoption in HIV-related lymphoma. Inequities in HCT utilization in HIV-related lymphoma are influenced by social determinants of health. Patients who are Black/African American, do not have private insurance, and have low socioeconomic status are less likely to receive HCT in general, but these barriers to HCT in HIV-related lymphoma have never been studied. This proposal will characterize the social determinants of health that influence HCT utilization in patients with HIV-related lymphoma, and elucidate if supportive measures are needed to address differences in care outcomes based on HIV status. Our central hypothesis is that in HIV-related lymphoma patients, certain social determinants of health are associated with less HCT utilization, and that PLWH have distinct treatment burden and hospital use. We will test our hypothesis via the following Specific Aims: 1) Measure the associations between sociodemographic and clinical factors on HCT utilization in patients with HIV-related lymphoma, and 2) Test for differences in treatment burden, hospital use, and survival outcomes between lymphoma HCT recipients with and without HIV. Our research team at UC Davis linked an innovative dataset using the Center for International Blood and Marrow Transplant Research (CIBMTR), California Cancer Registry, and California Patient Discharge Data that will be used in cohort and matched case-control designs in this F31 proposal. By completing the training objectives in this F31, the applicant will gain the skills necessary to become an independent nurse scientist and Principal Investigator, while characterizing inequities in HCT utilization and disparities in care outcomes influenced by social determinants of health. Specifically, through a mentoring team spanning UC Davis, UC San Francisco, and Stanford University the F31 applicant will 1) Acquire skills in epidemiologic approaches (population health), secondary analysis, and advanced biostatistics, 2) Gain HIV clinical management expertise, 3) Advance knowledge in health equity, health disparities, and social determinants of health, and 4) Leadership and professional development to become a principal investigator.

NIH Research Projects · FY 2026 · 2024-05

PROJECT SUMMARY / ABSTRACT These investigations explore the hypothesis that maternal inflammation due to acute or chronic virus infection during pregnancy has a durable impact on the development of the fetal immune system, which is mediated by changes in placental function and transplacental transfer of metabolites and inflammatory mediators to the fetus. Our studies have shown that subclinical rhesus cytomegalovirus (RhCMV) infection during pregnancy is associated with dramatic alterations of immune function in offspring—demonstrating a vertical effect of maternal inflammation on immune system development. Our prior studies have also demonstrated a fetal response that impacts how microglial cells, the resident immune cells of the central nervous system, engage and engulf neural precursor cells. These investigations will probe the link between maternal, placental, and fetal inflammation in a translational primate model system that closely recapitulates human development and disease, and using state-of-the-art tools and technologies through the following Specific Aims: (1) Determine the impact of acute maternal RhCMV infection and consequent inflammation on fetal innate and adaptive immune functions, in seronegative and seropositive dams; (2) Assess the impact of acute and chronic RhCMV infection on the placenta and maternal-fetal cell trafficking; and (3) Test the postnatal consequences of fetal immune development in the context of maternal infection with RhCMV and associated inflammation. The studies proposed are designed to test the hypothesis that maternal, placental, and fetal immune responses contribute to developmental sequelae including alterations in postnatal immunity, providing key insights on a common worldwide maternal and congenital infection.

NIH Research Projects · FY 2025 · 2024-05

Project Summary/Abstract: Autism spectrum disorders (ASD) are pervasive, highly prevalent lifelong disorders for which pharmacological interventions are not readily available. While genetic factors are likely contributors to these disorders, heritability estimates indicate strong environmental contributions. Of significant interest is the link between fetal gestation and the activation of the maternal immune system during critical periods of development. Epidemiological reports suggest a strong association between periods of maternal immune activation - including immune conditions such as allergies and asthma - and an increased risk of having a child with ASD. Acute exacerbations are common in pregnant asthmatic women, with as many as 35% suffering attacks requiring hospitalization. In addition, particulate matter from air pollution, a major exacerbating factor in allergic asthma, has been linked with an increased risk for ASD. This is particularly concerning given the increasing presence of particulate matter from wildfires, which are becoming more frequent and severe. Despite this, the consequences of gestational exposure to maternal asthma/allergy- mediated responses, wildfire particulate matter (WPM), or their combined effects on fetal development remain largely unknown. We recently developed a preclinical model of maternal allergic asthma (MAA) during gestation that alters neurobiology and microglial function and disrupts epigenetic mechanisms in offspring. We have WPM samples collected in situ and through proximity sampling of wildfire emissions, capturing the complexity of real-world complex WPM exposures. We will test the innovative hypothesis that WPM and MAA combined are causally linked to altered microglia activation and function and that these exposures lead to epigenetic modifications of microglia that will enable us to discover gene pathways that diverge or converge between the two exposures. The proposed studies will examine WPM alone and the exacerbating effects of WPM sampled from the Northern California region during fire season plus MAA on microglia activation and function (Aim #1). Environmental exposures during critical windows in early life can impact epigenetic mechanisms, and the developing brain is particularly susceptible to these changes. Over-activation of the maternal immune system, for instance, can lead to an over-activation of the fetal immune system, potentially hindering brain development. We will test the hypothesis that epigenetic mechanisms in microglia are altered by combined WPM + MAA (Aim #2). If successful, this research will validate the concept that neurodevelopmental disorders such as ASD is, for some, caused by environmental contaminants that alter immune mechanisms. Our findings could identify novel mechanisms and preventative strategies for one of the most visible public health concerns of our time.

NIH Research Projects · FY 2026 · 2024-05

Project Summary/Abstract We and others showed that ferredoxin reductase (FDXR), a mitochondrial flavoprotein, is induced by DNA damage in a p53-dependent manner and regulates apoptosis induced by reactive oxygen species. As the only human ferredoxin reductase, FDXR receives two electrons from NADPH and transfers them one at a time to its cognate substrates ferredoxin 1 (FDX1) and FDX2 and subsequently, plays a role in biogenesis of steroids and iron sulfur cluster proteins. Despite these well-defined biochemical functions, the role of FDXR in tumor suppression is still poorly understood. Interestingly, recent studies showed that FDXR is the most consistent acute sensor following DNA damage, suggesting that FDXR plays a role in DNA damage response and repair. Indeed, our pilot studies showed that FDXR is also expressed in the nucleus and regulates cell growth and survival potentially via its nuclear substrates (p53, Mdm2, and Mdm4) in response to a stress. These observations prompt us to hypothesize that the nuclear FDXR has a critical biological function in tumor suppression. To further test this, two specific aims are proposed: (1) To determine how FDXR subcellular localization is regulated; (2) To determine how the nuclear FDXR exerts its biological function.

NIH Research Projects · FY 2025 · 2024-05

PROJECT SUMMARY/ABSTRACT Ovarian cancer is the most lethal gynecologic malignancy for women; standard of care surgery and chemotherapy treatment can provide a short period of remission but cannot eradicate the disease and prevent recurrence. Cancer immunotherapy has shown great potential in treating cancers, but no clinical success has been reported for ovarian cancer. One major hurdle for cancer immunotherapy that is needed to overcome is to convert the immunosuppressive tumor microenvironment (TME). The goal of this proposal is to develop effective nanomedicines that are capable of reprogramming and converting the suppressive TME for ovarian cancer treatment. To achieve this goal, I will utilize viral nanoparticles (VNPs) to incorporate various functionalities targeting different aspects of the TME through bioengineering approaches. The two VNPs that will be used in this proposal are cowpea mosaic virus (CPMV) and hepatitis B virus capsid (HBVc), which both have well-characterized and stable structures for in vitro bioengineering. Toll-like receptor (TLR) agonists have been demonstrated to be potent to activate the innate immune system and modulate the TME. CPMV is a triple TLR 2, 4, and 7 agonist and is effective to reprogram the TME of ovarian cancer. In the mentored K99 phase, I will focus on using CPMV as a triple TLR agonist to develop an adjuvant and antigen combination in-situ vaccine for ovarian cancer treatment (Aim 1) and developing multi-TLR agonists to investigate the mechanism of action (MOA) of CPMV and multi-TLRs activation in cancer treatment to design potent TLR agonists combination for downstream applications (Aim 2). During my independent R00 phase, I will use HBVc as a nanotechnology platform to develop multiple functional therapeutic nanomaterials aiming to reprogram the suppressive TME to treat ovarian cancer and investigate the MOA. First, I will develop HBVc-based TLR agonist and pro-inflammatory cytokine combination therapies, which can exert the functions of reprograming the TME and killing cancer cells concurrently (Aim 3). Secondly, I will develop HBVc into a “smart” nanoparticle that functions as a TLR agonist and targets and converts the pro-tumor M2 macrophages into anti-tumor M1 macrophages (Aim 4). During my graduate study, I have been trained in manipulating HBVc in vitro assembly and genetic engineering of HBVc to design novel structures. In the past two and a half years as a postdoc in Dr. Steinmetz’s lab at UCSD, I have been trained systematically in the bioengineering of VNPs and the application of engineered VNPs for cancer treatment. A further two years of training in Dr. Steinmetz’s lab will allow me to enrich my background in cancer immunology, immune-oncology, and tumor modeling. With the help and guidance from my advisory committee, by the end of my mentored phase, I will be able to secure a tenure-track faculty position in a top-tier research institute to establish my independent research program focusing on using HBVc as a nanotechnology platform to develop novel and effective multi-functional nanomedicines for cancer patients.

NIH Research Projects · FY 2025 · 2024-05

Project Summary: The long-term objective of this work is to define the molecular mechanisms underlying proprioceptive signaling that are required for sensory-driven motor behaviors. Proprioception encodes body and limb position, which is essential for purposeful movement. Yet, the lack of tools to selectively target genes in proprioceptors, the sensory neurons that carry proprioceptive signals, has impeded our understanding of the molecular mechanisms underlying this vital "sixth sense." Voltage-gated sodium channels (NaVs) are critical for neuronal signaling in the nervous system, and proprioceptors express three isoforms: NaV1.1, NaV1.6, and NaV1.7. We recently discovered that loss of NaV1.1 in sensory neurons causes ataxic-like behaviors and abnormal limb positioning and impaired proprioceptor transmission during static muscle stretch. While loss of NaV1.7 has no impact on motor function in mice or humans, NaV1.6 is known to contribute to the function of brain neurons involved in motor control. Thus, our lab created a sensory neuron-wide knock out of NaV1.6 and found that these animals have extremely severe motor coordination deficits distinct from those observed in NaV1.1 conditional knockout animals. This proposal will uncover the mechanistic role of NaV1.6 in proprioceptive signaling by developing the first CRISPR/Cas9 intersectional genetic and viral strategy to manipulate genes in selectively proprioceptors. The work outlined herein will test the central hypothesis that the unique cellular localization patterns and intrinsic properties of NaV1.6 underly the transmission of proprioceptive signals to spinal motor circuits for motor behaviors. I test this hypothesis using the following mechanistic aims: Aim 1 will analyze the cellular distribution patterns of NaV1.6 channels in proprioceptive sensory neurons. Aim 2 will investigate how loss of NaV1.6 changes proprioceptor biophysical properties and excitability. Aim 3 will leverage an intersectional gene knock out model to investigate how acute deletion of NaV1.6 proprioceptors affects sensory-motor circuit function and motor behaviors, overcoming a long-standing challenge in the field. NaV1.6 is associated with brain-related diseases like epilepsy and autism spectrum disorder. Symptoms of these diseases include motor-related deficits; however, our understanding of the mechanisms that give rise to these comorbidities outside the brain is understudied. The proposed herein are directly in line with the goals of NINDS as it will 1) advance our knowledge about mammalian proprioception and 2) shed new light on critical roles of peripheral sensory neuron signaling in neurological disorders. Furthermore, this proposal will not only provide critical me new training in molecular biology and biochemistry techniques, but also offer the scientific community a new and exciting approach to gene manipulation in challenging- to-target neuronal populations.

NIH Research Projects · FY 2026 · 2024-04

Project summary Exposure to social stressors is an important risk factor for the development of mental illnesses such as anxiety, depression, and post-traumatic stress disorder. Stress-related mental illnesses are more common in women than men, and these differences arise during adolescence. Androgens work to change brain structure and function during adolescence, how this transformation impacts behavior is poorly understood. We will test the hypothesis that the activation of androgen receptors during puberty permanently programs neural circuits of social behavior to be less sensitive to social stress. Our studies will be conducted using California mice (Peromyscus californicus), an ideal model system for studying adolescent development. In this species adolescence lasts almost twice as long as conventional mice and rats, which will allow us to apply advanced neuroscience and molecular methods in way that would be difficult or impossible in standard model systems. In adult California mice, females but not males exposed to social defeat stress orient towards an unfamiliar target mouse while simultaneously avoiding it, a behavior we define as social vigilance. However, in juvenile California mice, social stress increases social vigilance in both males and females. In males, prepubertal castration results in female-typical social vigilance responses in adulthood, while pubertal treatment with the non-aromatizable androgen dihydrotestosterone reduces sensitivity to social stress in both males and females. We will test the hypothesis that activation of the androgen receptor (AR) during puberty permanently programs neural circuits of social behavior to be less sensitive to social stress. First, we will use CRISPR-based gene editing to knock-down AR expression in ventral hippocampus (vHPC) neurons projecting to the bed nucleus of the stria terminalis (BNST) or nucleus accumbens (NAc). The prolonged development of this species will allow us to knock-down AR expression before the onset of adolescent development. Second, we will use state-of-the-art sequencing methods to identify AR genomic binding sites in the vHPC and assess maturation of hippocampal cells with single-cell resolution. Finally, we will determine how circuit-specific AR knock-down alters membrane excitability of vHPC neurons using whole- cell slice electrophysiology. These analyses bridge the gap between the molecular and behavioral data in the other aims. Our team is ideally suited to execute these studies. Dr. Trainor is a leader in developing the California mouse stress model and open access tools. Dr. Tollkuhn is a leader in the application of modern sequencing methods to identify the molecular mechanisms of sexual differentiation of the brain. Dr. Robison is a leading expert in the use of electrophysiological approaches to study the impact of stress on neural circuits. The proposed studies will be the first to identify androgen-dependent molecular pathways activated during adolescent development in neural circuits that drive translationally relevant behavioral responses to stress.

NIH Research Projects · FY 2026 · 2024-04

Project Summary ANGEL2 is an RNA-binding protein (RBP), and member of the catabolite repression 4 (CCR4) family of proteins, which are involved in the modulation of mRNA stability and translation. With clinical significance, decreased ANGEL2 expression across 17 different cancer types is correlated with both poor overall and disease-free survival. However, the molecular mechanisms by which ANGEL2 modulates tumorigenesis have yet to be determined. Gene expression correlation analysis revealed a functional relationship between ANGEL2 and the tumor suppressor TP53. Consistently, ANGEL2 deficiency caused a substantial loss of TP53 expression and resulted in multicellular tumor spheroids adopting a stellate/invasive morphology. In addition, an ANGEL2-derived peptide increased TP53 expression and decreased multicellular tumor spheroid growth. TP53 is a transcription factor and stress sensor which plays an integral role in maintaining the genome. Inactivation of TP53 occurs in more than 50% of human cancers, and is a hallmark of tumor progression and chemoresistance. It is therefore widely recognized that loss of wild-type TP53 expression/function is a driver of tumor progression. Consequently, determining the key modulators of TP53 is paramount for the understanding of tumorigenesis and the development of the novel therapeutic approaches. This project aims to elucidate the role of ANGEL2 in TP53-dependent tumor suppression, and to determine if this pathway can be targeted to enhance wild-type TP53 expression and suppress tumor growth. Utilizing ANGEL2 knockout cell lines, coupled with xenograft and patient-derived organoid models, the effect of ANGEL2 on TP53 expression, and TP53-dependent tumor suppression will be determined. Moreover, the use of molecular and biophysical tools to design and modify ANGEL2-derived peptides to upregulate wild-type TP53 expression will be explored as a therapeutic approach for malignancies which carry wild-type TP53. These studies will guide the career development of Dr. Christopher Lucchesi by providing relevant knowledge and skills obtained through collaborations and courses in molecular and biophysical techniques, 3D-organoid tumor modeling, peptide drug design, translational research and leadership skills. Dr. Lucchesi will also profit from the wealth of available resources at UC Davis to equip him with the necessary skillsets to reach his career goals. Through training in this collaborative, ‘One Medicine’ environment, Dr. Lucchesi will be a competitive, independent investigator and a leader of a successful and productive research team.

NIH Research Projects · FY 2025 · 2024-04

Project Summary This proposed research aims to provide a roadmap for studying dopamine dynamics using a novel optical tool, dLight, deepening our understanding of dopamine biology. Altered dopamine signaling is central to many neurological and neuropsychiatric disorders, yet we lack effective treatments for these disorders. Many existing treatments act on dopaminergic systems, but they act on slow time scales and do not work for all patients. Deepening our fundamental understanding of dopamine biology can lead to the discovery of improved treatments. The Tian lab developed dLight, which is an optical biosensor that can directly record dopamine signaling in vivo with high precision. The proposed work aims to determine the performance metrics of the newest dLight variants in vivo and use the sensor to measure alterations in dopamine activity in a disease model. Specifically, I will measure differences in dopamine signaling between offspring of the maternal immune activation model and healthy controls, as offspring from this model have been shown to have altered dopamine signaling systems. Additionally, I will create a database of the data collected to share with the neuroscience research community, increasing the accessibility of dLight and enabling researchers to use this novel tool in their own research. Successful completion of this project has the potential to transform our understanding of dopamine biology and significantly contribute to the development of effective treatments for many neurological and neuropsychiatric disorders.

NIH Research Projects · FY 2026 · 2024-04

PROJECT SUMMARY Autism spectrum disorder (ASD) is part of a larger group of neurodevelopmental disorders (NDDs) and is diagnosed in more than 1% of the human population1-3. Patients with severe forms of ASD live with debilitating symptoms that can prevent them from living independent lives. ASD has a strong genetic component, but is genetically heterogenous1, 4-7. Whole exome studies have identified hundreds of risk loci, including the Chromodomain Helicase DNA-binding protein 8 (CHD8) gene2, 8-12. CHD8 is a chromatin remodeling factor (CRF)13-16 and has a high occurrence of de novo loss-of-function mutations in ASD cohorts8-11, 17-20. Moreover, along with ASD, CHD8 mutation carriers frequently exhibit intellectual disability (ID), macrocephaly, and gut dysfunction21-22. Our lab generated and characterized mice with germline heterozygous loss of function mutations to Chd8, finding macrocephaly and disrupted cognitive function, as well as ASD relevant transcriptional pathology during neurodevelopment23. While we and others have characterized Chd8 mutant mouse lines and human in vitro models, the molecular underpinnings of core ASD pathology in Chd8 haploinsufficient mice are still not well understood. CHD8 has been shown to bind regulatory targets in the genome in brain development and adulthood, impacting neurodevelopmental gene expression programs. The primary hypothesis in the field is that CHD8 haploinsufficiency drives ASD pathology by first disturbing neurogenesis and developmental processes, but there may also be disturbances to synaptic function in adulthood that perpetuate and exacerbate cognitive and behavioral symptoms23-24. In addition to core symptoms, 69% of ASD patients exhibit increased neuroinflammation or microglial activation25. Studies on postmortem ASD brain samples indicated increased expression of immune related genes27-28. The neuroimmune interface in Chd8 haploinsufficient mice has yet to be characterized in significant detail, and the neuroimmune signatures seen in human ASD patients have not previously been observed in mouse models. Intriguingly, our transcriptomic studies have revealed preliminary evidence of perturbed immune pathways in the brain23. Whether these immune symptoms are an intrinsic part of CHD8-mediated pathology or secondary to disruptions in other pathways is uncertain. In this proposal, I will leverage Chd8 mutant mice to elucidate cell-specific transcriptomic mechanisms associated with Chd8 haploinsufficiency and NDD-associated pathology. My studies will secondly test for microglia-specific effects of Chd8 mutation and map the relationship between immune and neuronal signatures in the brain. This work will comprehensively expand the breadth of our understanding of molecular pathology across cell types in the adult brain, as well as interrogate at depth the impacts of Chd8 haploinsufficiency on neuroimmune signaling and microglia. Overall, these studies may provide novel insights into cellular and molecular origins of NDD pathology as well as yield new insights into neuronal-microglial interactions in the brain in severe monogenic NDDs.

NIH Research Projects · FY 2026 · 2024-04

The incretin receptors, glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR), are therapeutic Type 2 Diabetes Mellitus (T2DM) targets. Incretins bind to their respective receptors on beta () cells to activate adenylyl cyclases (ACs) and generate cAMP, the second messenger necessary to potentiate glucose-stimulated insulin secretion. Although GIPR and GLP-1R are Gs- coupled GPCRs that share the same downstream signaling cascades, I discovered that they elicit profoundly different kinetics of cAMP generation in primary  cells. The mechanisms underlying the difference between GIPR and GLP-1R signaling are unknown. Furthermore, a direct comparison of the signaling and trafficking between GIPR and GLP-1R in primary  cells has not been performed. This knowledge gap prompts the need to improve our understanding of incretin signaling towards more effective T2D treatments. Details of the kinetics of incretin-induced cAMP responses and how they are affected by GPCR trafficking and the nutrient stimulated Ca2+ responses, are not well established. By imaging genetically encoded cAMP sensors expressed in  cells, I have identified differences in the cAMP kinetics of  cells to GIP and GLP-1 stimulation. I propose that these stark differences connect to differences in receptor trafficking and may explain in part the known differences in effectiveness between both incretins. Furthermore, I also discovered that incretin-mediated cAMP production is paradoxically inhibited by Ca2+ induced by glucose and other stimuli, suggesting a dynamic interaction between Ca2+ and Ca2+-regulated ACs that shapes the kinetics of cAMP formation and determines the  cell insulin secretory response to nutrient and incretin co-stimulation. My overarching hypothesis is that receptor trafficking, -Arrestin preferences, and the interplay between Ca2+ and ACs underlie dynamic cAMP kinetics of  cells in response to nutrient and incretin co-stimulation. I will test this hypothesis in two separate aims that converge on the functional imaging of primary  cells. In Aim 1, I will quantify trafficking of SNAP-tag incretin receptors co- expressed with a genetically encoded cAMP sensor in HEK293 cells and primary mouse  cells to determine how incretin receptor trafficking influences cAMP responses. I will also assess changes in incretin-mediated cAMP responses in the absence of -Arrestins. In Aim 2 I will multiplex genetically encoded cAMP and Ca2+ sensors to determine the interplay between cAMP and Ca2+ across hundreds of  cells in islets that lack key ACs. These approaches are innovative as they leverage novel transgenic mouse that expresses endogenous SNAP-tag GLP-1R in every  cell in islets. Separately, I can quantify cAMP and Ca2+ dynamics in the same cells using genetically encoded spectrally compatible fluorescent sensors. These proposed aims are significant as they will provide a comprehensive understanding of the mechanisms and kinetics that dictate how different incretins achieve insulin release under nutrient stimulation. This understanding carries significant weight in the development of improved incretin dual agonists to treat T2DM and improve patient outcomes.

NIH Research Projects · FY 2026 · 2024-03

Pancreatic islet crosstalk is essential to maintain blood glucose homeostasis. Central to this crosstalk are the somatostatin (Sst)-secreting delta cells, which serve to regulate the activity of insulin-secreting beta and glucagon-secreting alpha cells. Crosstalk between beta and delta cells is of particular importance as it is often lost or dysregulated in diseases characterized by dysglycemia like diabetes and congenital hyperinsulinism (CHI). It is well established that insulin and Sst secretion are coordinated, but there is no consensus on the mechanism of this coordination. Published data demonstrating a 30 second lag between insulin and Sst secretion coupled with our previously published observation that the beta cell hormone Urocortin 3 stimulates delta cell Sst secretion illustrate the importance of paracrine coordination of beta-delta cell secretion. However, an alternative and potentially parallel mechanism is gap junction coupling. Preliminary data using the calcium reporter GCaMP6s simultaneously expressed in beta and delta cells demonstrates that delta cell response to high glucose is profoundly heterogenous compared to beta cells, with both beta cell coordinated and uncoordinated calcium oscillations observed in the majority of delta cells. Based on these data delta cells can be subdivided into 7 distinct subpopulations suggesting that a single mechanism may be insufficient to fully describe beta-delta cell coordination. This has informed the hypothesis that delta cells coordinate with beta cells predominantly via paracrine signaling with a minor subpopulation of highly synchronous delta cells showing calcium behaviors consistent with gap junction coupling. The mechanism(s) of crosstalk between beta and delta cells will be addressed in two aims. Aim 1 will focus on how gap junction coupling could contribute to coordinating a small subpopulation of highly synchronous delta cells. Aim 2 will focus on the role paracrine signaling plays in coordinating the majority of delta cells with beta cells during glucose stimulation. To assess the extent of gap junction coupling in Aim 1 the whole cell patch clamp technique will be used to deliver small gap junction permeable tracers into beta and delta cells within intact islets. To investigate the role of gap junction coupling between beta cells and this small subset of highly synchronous delta cells live cell Ca2+ imaging will be followed by post-hoc immunohistochemical staining of Cx36. To address the predominant role of paracrine signaling in coordinated delta and beta cell activity in Aim 2, inhibitors of secretion will be used while assessing changes in the level of coordination between beta and delta cells via Ca2+ imaging. These approaches are innovative by: 1) connecting heterogeneous delta cell behavior to underlying mechanisms of coordination in response to glucose stimulation in intact islets. 2) resolving the predominant mechanism(s) of coordination between beta and delta cells. These aims are significant as they will definitively establish the mechanism(s) by which beta and delta cells communicate to coordinate their activity in response to high glucose, paving the way for the development of novel therapeutics aimed at re-establishing healthy islet crosstalk in diseases like diabetes and CHI.

NIH Research Projects · FY 2026 · 2024-02

ABSTRACT Epidemiological evidence indicates individuals with insulin resistance (IR), dyslipidemia characteristic of metabolic syndrome (MetS) and type-2 diabetes mellitus (T2DM) are at heightened risk for developing Alzheimer’s disease (AD) and Alzheimer’s disease related dementias (ADRD). To examine mechanisms whereby MetS/IR/T2DM contribute to dementia risk and vice versa, we will employ a validated nonhuman primate (NHP) model that employs a high sugar diet (HSD) that accelerates the progression MetS/IR/T2DM, including rapid induction of IR, systemic inflammation and dyslipidemia. We propose a longitudinal investigation of the relationships between metabolic dysfunction, diabetes, and dementia over the course of one year with NHPs on HSD. A comprehensive, integrated analysis of central and peripheral endpoints is proposed, specifically synaptic through biochemical, immunochemical, transcriptomic, and proteomic assessments of the hippocampus, cortical regions comprising the default network mode (DMN), and mediobasal hypothalamus (MBH) via advanced imaging (MRI and PET), and molecular/cellular studies linking neuropathology, inflammation, mitochondrial and vascular dysfunction, and behavior in MetS/IR/T2DM with AD and ADRD. We will employ this highly translatable NHP model to investigate the mechanisms underlying how MetS/IR/T2DM drives AD/ADRD and vascular pathology, and why AD/ADRD/vascular dementia aggravate MetS/IR/T2DM in a vicious cycle. We will assess vulnerable circuits and regions comprising memory (hippocampus), executive function (DMN), MBH with parallel assessments of biobehavior, cerebrovascular function, blood-brain-barrier (BBB), and peripheral pathways, especially targeting inflammation. Synaptic, and circuit level dysfunction will be quantified in the context of biobehavioral and peripheral metabolic outcomes and advanced imaging, including regional brain blood flow and glucose utilization. Aim 1 tests the hypothesis HSD in NHPs initiates AD/ADRD- like pathology and vascular impairment within vulnerable regions underlying memory and executive function, providing a mechanistic link between MetS/IR and pathological cascades in dementia. Aim 2 tests the hypothesis that HSD produces functional deficits in the brain and periphery in macaques with MetS/IR/T2DM to increase risk of AD, ADRD, and/or vascular pathology and behavioral deficits. Mechanistic investigation will be executed by evaluating neuropathology, biobehavioral parameters, vascular/BBB perturbations, neuroinflammation, impairments of insulin signaling and mitochondrial mass/function with changes in peripheral tissues (e.g., liver) by coordinated immunochemical, proteomic, transcriptomic, and advanced imaging assessments in the same animals. We propose rigorous assessments of the pathological effects of systemic MetS/IR/T2DM on the brain and cerebrovasculature and molecular and cellular architecture in a validated NHP model to recapitulate these prevalent, interrelated disorders. Results from NHPs are highly translational, and will contribute to innovative approaches for managing and ameliorating deleterious effects of MetS/IR on AD/ADRD pathology and dementia.

NIH Research Projects · FY 2026 · 2024-02

Abstract DESCRIPTION: Influenza viruses can exchange genome segments and generate new viruses when they infect the same cell, a process called reassortment. These new viruses can worsen seasonal flu epidemics or spark global pandemics. We recently found that patterns of reassortment show strong strain-dependence, and do not necessarily track similarity between coinfecting strains or their subtype (H1N1 or H3N2). The specific factors underlying this strain dependence remain unclear. The role of protein incompatibilities in restricting segment exchange was thought to be associated with different subtypes. However, experimental tests of the role of subtype in promoting or restricting reassortment remain very limited, and the specific protein incompatibilities (antigenic versus polymerase complex) that are most important in shaping reassortment remain unknown. Using our high-throughput tools, we propose to uncover the basis of strain dependent reassortment potential. First, we will quantify reassortment patterns within and between co-circulating human influenza strains of both subtypes and measure differences in entry and coinfection. Second, we will use mutants to test the effect of antigenic versus polymerase complex segments in driving reassortment potential. Finally, we will examine whether post-reassortment mutations can compensate fitness in strains arising from between-subtype reassortment and their fitness in different host cell types. Collectively these aims will provide basic insight into the factors affecting strain dependence in reassortment potential and provide actionable data to refocus surveillance and pandemic preparedness efforts.