University Of California Riverside

NIH Research Projects · FY 2026 · 2024-02

The goal of the proposed research is to discover new mechanisms underlying the development of hyperactive neuronal networks in the brain. Hyperactivity of neuronal networks due to the loss or impaired function of inhibitory neurons can lead to neural dysfunctions and seizures. Both impaired inhibition and glial dysfunctions have been linked to several neurodevelopmental disorders including autism. Autism is an increasingly prevalent neurodevelopmental disorder that affects approximately 1 in 59 children in the United States. We hypothesize that ephrin- B/EphB receptor signaling controls the development of inhibitory networks by regulating the interactions between pyramidal neurons and parvalbumin-expressing (PV) cells that are critical for normal development. Premise of the study is supported by our new and unexpected discovery that implicated astrocytic ephrin-B1 and Ephrin-B/EphB receptor signaling in the development of connections between inhibitory PV cells and excitatory pyramidal cells in the hippocampus. Our preliminary findings also show that loss of astrocytic ephrin-B1 increases susceptibility to seizures and reduces sociability in mice. As genetic studies have linked de novo variants in gene encoding EphB2 receptor with autism spectrum disorders (EPHB2 gene is identified as a strong candidate with score 2 in SAFARI database), this study may also contribute to our understanding of the pathophysiological mechanisms of these brain disorders. We will test our hypothesis in three specific aims: Aim 1 will determine if EphB receptors expressed in PV and SOM cells negatively regulate inhibition of CA1 pyramidal neurons by examining the effects of PV- and SOM-specific ablation of EphB2 and EphB1 on the inhibitory synapse development in the hippocampus during critical developmental period using biochemical, immunohistochemical and optogenetic approaches. Aim 2 will determine the mechanism of EphB signaling in regulating inhibitory synapse formation by establishing the role of the neuronal ephrin-B/EphB signaling in inhibitory synapse formation. Aim 3 will test if astrocytic ephrin-B1 positively regulates inhibitory synapse formation on pyramidal cells through the displacement of EphB receptors from PV boutons. The proposed study will further our understanding of the mechanisms which lead to neurodevelopmental disorders and will allow us to discover novel interventions for treating these disorders through targeting EphB receptor signaling and astrocytes during specific developmental period.

NIH Research Projects · FY 2025 · 2024-01

Project Summary/Abstract Threat vigilance facilitates adaptive defensive responses and is advantageous in the case of real threats. However, when extreme and persistent, it can result in excessive fear and avoidance, core features of anxiety. Theoretical models of anxiety posit that hypervigilance towards threat may elicit, maintain, or even exacerbate anxiety symptoms. Indeed, relative to healthy participants, anxiety patients show greater psychophysiological responding and dysregulated neurocircuit function in many threat-anticipatory states. Whether and how such perturbations are impacted by threat-relevant psychosocial factors, such as ethnic-racial (ER) discrimination and ER socialization, is less well understood, particularly in adolescence when anxiety risk is elevated. To address this gap in knowledge, the current proposal builds on an existing longitudinal study to examine the social experiences that exacerbate anxious hypervigilance in preadolescent Latina girls aged 8-13 years, a group exhibiting high levels of untreated anxiety that is also differentially and excessively exposed to ER discrimination. The specific aims of this proposal are (1) to understand the effect of ER discrimination on behavioral and neurophysiological indices of anxious hypervigilance in Latina girls, and (2) to explore main and moderating effects of parental ER socialization on anxious hypervigilance and the association between ER discrimination and anxious hypervigilance, respectively. Anxious hypervigilance will be assessed during two task-based measures via social judgements of emotionally ambiguous face stimuli, sympathetic and parasympathetic responses, and neural activity. Child anxiety symptoms, ER discrimination, and parental ER socialization will be assessed via survey-based measures. In sum, through this project, I will explore possible longitudinal, biological, and social sequelae of ER discrimination and ER socialization, characterize parental ER socialization practices as potential protective factors, enhance my knowledge of neurophysiological and longitudinal data analysis, and contribute to culturally-informed intervention and prevention efforts aimed at reducing anxiety in minoritized youth.

NIH Research Projects · FY 2026 · 2023-12

PROJECT SUMMARY Vibrio cholerae is a Gram-negative bacterium and the etiologic agent of cholera, a severe human diarrheal disease characterized by voluminous watery diarrhea and vomiting and when left untreated, severe dehydration, hypovolemic shock, and death. Several oral cholera vaccines (OCV) have been developed but demonstrate variable efficacy in distinct geographical regions. Thus, defining the factors that modulate such variation and developing strategies to minimize variability in prophylactic efficacy remains a significant global health priority. One host-associated factor that has demonstrated differences in composition and functional output between populations of high and low OCV efficacy is the commensal microbial community of the gastrointestinal tract, the gut microbiota. Our central hypothesis is that interpersonal variation in the microbial community of the gastrointestinal tract contributes to significant interpersonal variation in OCV responses caused by microbe-specific modulation of the intestinal immune system. Our preliminary data suggest that the gut microbiota may acts a personalized contributor to oral cholera vaccination outcome, whereby (i) specific microbial taxa correlate with distinct immune responses to oral cholera vaccination; (ii), inter-individual variation in microbiota structure and (iii) dysbiotic microbiotas, representative of gut microbial communities found in cholera endemic areas, directly influence infection and vaccination outcomes to V. cholerae; and (iv) modulation of host intestinal CD4+ T-cells regulate host immune responses to V. cholerae challenge. Precision editing of the gut microbiota may represent an effective strategy to enhance oral vaccine responsiveness, but such approaches will require a detailed understanding of the specific microbe(s) involved and the particular mechanisms by which they enhance or inhibit human immunophenotypes of interest, particularly in the context of oral vaccine responses. Our ultimate goal is to identify specific microbial taxa that drive differential immune responses to V. cholerae, as such candidates may better inform the development of gut microbiota-targeted prebiotic and probiotic strategies for cholerae prophylaxis. We will address this problem with the following study aims: Aim 1 - Determine the effect of inter- individual microbiota variation on OCV responsiveness; Aim 2 - Define immune cell populations that mediate microbiota-driven effects on OCV responses.

NIH Research Projects · FY 2025 · 2023-12

PROJECT SUMMARY The human pathogen Vibrio cholerae causes cholera, a severe human diarrheal disease that affects millions of people annually. A number of oral cholera vaccines (OVC) have been developed but show varying efficacy among populations in distinct geographical regions, with poor OCV response being common in cholera endemic areas. However, the underlying causes of this variation are poorly defined. There is therefore an unmet global health need to develop strategies that boost the effectiveness of these lifesaving OCVs. The resident microbial community of the gastrointestinal tract, the gut microbiome, varies significantly among individuals, and this variation has been linked to variation in host phenotypes and responses to therapeutics. Our central hypothesis is that inter-individual variation in the microbial populations of the gut contributes to the high level of geographical variation in OCV efficacy through effects on the intestinal immune system. Our preliminary data shows that the gut microbiome represents a personalized contributor to OCV outcome; (i) specific gut bacterial taxa correlate with high and low responsiveness to OCV, inter-individual microbiota variation in cholera endemic areas (ii) directly impact infection outcome and immune responses to V. cholerae and (iii) recapitulates human donor OCV outcomes in a germfree mouse transplantation model, and (iv) gut microbiome modulation of host CD4+ T cells critically regulates immune responses to V. cholerae. Precision editing of the gut microbiome therefore represents an attractive strategy to boost OCV responsiveness, but implementation of such approaches requires detailed understanding of the specific microbes responsible, and the nature of their interactions with the host immune system. We will leverage our team’s expertise in OCV clinical studies, metagenomics, anaerobic microbiology, intestinal immunology, and gnotobiotic mouse models to make causal and mechanistic links between structural variation in the gut microbiome and human vaccine responsiveness, and to identify specific microbes able to drive strong OCV outcomes. Our ultimate goal is to identify specific microbial taxa that drive divergent immune responses to V. cholerae, which may then inform microbiome-targeted probiotic and prebiotic strategies for cholera prophylaxis. We will address this problem through the following Specific Aims: Aim 1- Determine the effect of inter-individual microbiota variation on OCV responsiveness; Aim 2- Define the microbiota targets that enhance responsiveness to oral cholera vaccines; Aim 3- Define the immune cell populations that mediate microbiota-driven effects on OCV.

NIH Research Projects · FY 2025 · 2023-12

Project Summary / Abstract The gut microbiota plays a crucial role in various aspects of host health, including resistance against pathogen colonization. Phages, viruses that infect bacteria, can impact the composition and function of the gut microbiota, leading to changes in gene expression, metabolic activity, and/or acquisition of novel traits. Our research focuses on how phages interact with the gut microbiota and influence infection outcomes, specifically in the context of Vibrio cholerae (Vc) infection, the causative agent of cholera. We have determined that differences in gut microbiota-mediated bile metabolism are key factors in personalized outcomes of Vc infection. As Vc uses bile in the gut to regulate its virulence gene expression during infection. The gut microbiota, particularly the Bacteroidota, can modify the bile pool via enzymes called bile salt hydrolases (BSHs), which converts bile acid molecules from those that strongly induce Vc virulence to weakly inducing forms, thereby disrupting the regulatory cascade of Vc. We have also found that phage infection in Bacteroidota can lead to significant changes in gene expression, including the repression of a sensory protein (TspO) that regulates BSH activity, resulting in increased ability to deconjugate bile acids and reduce Vc colonization. Based on these findings, we hypothesize that phage infections in closely related strains and species of Bacteroidota lead to conserved changes in gene expression, disrupting Vc colonization through up- regulation of BSH activity, while other genes regulated by TspO increase vulnerability to Vc competition. To test our hypotheses, we will (Aim I) track phage mobilization in gut microbes using fluorescent protein reporters and characterize the effect of phage on BSH activity in new hosts. We will also (Aim II) investigate the consequences of commensal phage on Vc infection using mutagenesis and co-colonization experiments, to identify the genetic determinants responsible for Vc antagonism of Bacteroidota without phage. These studies will provide valuable insights into the role of commensal phages in modifying gut bacterial bile salt sensing and deconjugation, and contribute to our understanding of how phage-mediated processes can be harnessed for prophylactic interventions against gastrointestinal pathogens such as V. cholerae. Further understanding of the interactions between phages and the gut microbiota will enable the development of strategies to manage and potentially engineer the effects of phage-mediated processes on community dynamics and host health. Overall, our research sheds light on the complex interplay between phages, gut microbiota, and host-pathogen interactions in the context of Vc infection, with potential implications for personalized medicine and interventions against infectious diseases.

NIH Research Projects · FY 2025 · 2023-11

Obesity incidence is increasing worldwide with the urgent need to identify new therapeutics. Increased adiposity is associated with chronic inflammation, which can exacerbate a number of obesity-associated diseases, including COVID-19 infection and allergic disease. There are profound sex differences in immune cell activation driving obesity-mediated pathologies. However, there remain critical gaps in knowledge on the immune mechanisms underlying obesity, and whether they are sexually dimorphic. Preliminary data generated from transgenic mice, adoptive immune cell transfer, and adipose single cell sequencing uncovered a new RELMα-eosinophil-macrophage axis that is female-specific and protective in obesity and associated inflammation. Transcriptomic profiling of the adipose macrophages identified novel sex-specific and RELMα-dependent genes such as chemokines, hemoglobins and a long non- coding RNA (lncRNA) as new molecular candidates to treat obesity. Based on these findings, the overarching goal of this study is to investigate sexual dimorphism in innate immune cell crosstalk in obesity, from how gonadal hormones direct macrophage-eosinophil interaction (Aim 1) to determining downstream effectors in macrophages, such as hemoglobins and lncRNA, and their mechanisms of action associated with oxidative stress in the obese adipose tissues (Aim 2). Strengths of the proposed study include the multidisciplinary nature of the experimental design, which combines the co-PIs expertise in reproductive endocrinology and innate immunity, and the public health impact of investigating the understudied area of sex differences and how they may guide more specific treatments for obesity and associated risks for infection and allergic disease.

NIH Research Projects · FY 2025 · 2023-09

The United States has led the world in drug discovery for over 50 years; however, the majority of scientific ideas that progress to clinical trials frequently come from Comprehensive Cancer Centers. Unfortunately, not all local universities and colleges have the resources to take their ideas forward to drug development and clinical trials. Through a partnership between University of California, Riverside (UCR) and City of Hope Comprehensive Cancer Center (CoHCCC), we aim to develop the resources, infrastructure, and training to help 1) UCR take their scientific ideas forward to develop therapeutic agents and ultimately initiate clinical trials and 2) mentor the next generation of drug development researchers and clinical trialists. Building on our successful P20 grant, in this U54 partnership, UCR and CoHCCC aim to develop the collaborations, resources, and training programs to improve drug development throughout the entire drug development pipeline. Our goal is for this program to become a focal point for UCR and CoHCCC to mentor and train cancer biologists, therapeutic and drug development scientists, and clinical trialists. Already, our P20 has fostered joint R01 grants, K01 grants, and pre-/post-doctoral fellowships. Both institutions are highly committed - CoHCCC contributed over $800K to our P20 grant and will contribute $250K/year to ensure the success of this U54 partnership. Aim 1 will strengthen UCR’s cancer research capacity and develop the resources to increase UCR/CoHCCC’s ability to jointly develop therapeutic agents. Aim 2 will increase the capacity of UCR and CoHCCC to jointly develop drugs and improve health. Aim 3 will provide the training, opportunity, and mentorship to foster the next generation of therapeutic scientists and clinical trialists.

NIH Research Projects · FY 2025 · 2023-09

Abstract Native Hawaiians/Pacific Islanders (NPI) in the U.S. are a rapidly growing racial group that suffers severe alcohol-related disparities. In NPI communities, young adults (18-30 years) endure the greatest burden of alcohol use disorders (AUD) and alcohol-related harms with our earlier NIAAA R21 study revealing that almost 50% of community-dwelling NPI young adults are at heavy risk for, or have, AUDs with 40% experiencing alcohol-related harms (e.g., health, social, work). Despite this, NPI young adults have received minimal alcohol research attention, leading to a lack of effective interventions to prevent or reduce their extreme AUD risk. Guided by the findings of our NIAAA R21, this resubmitted R01 study will respond to this public health gap by refining and efficacy testing SPEAR (Strategies for Pacific Empowerment and Alcohol Reduction): a novel culturally grounded AUD prevention intervention for NPI young adults. Building on our R21-developed Model of SPEAR intervention components for NPI young adults (previously chosen and shaped in our R21 by NPIs from existing AUD prevention interventions), in Aim 1, we will assemble our treatment manual from our NPI-shaped R21 AUD prevention components. To assemble the manual, we will use our culturally congruent intervention design methodology for NPIs involving an Advisory Council of community experts and citizens’ panels—an innovative research approach that mirrors NPI collective decision-making practices—to obtain critical feedback for refining SPEAR content/components from NPI young adults with high AUD risk and informal NPI providers. In Aim 2, we will review and refine our treatment components and manual through expert review by 3 leading alcohol research experts and feasibility pilot test the manual with 36 NPI young adults with high AUD risk for feasibility, acceptability, and impact, using our findings to finalize SPEAR for our randomized controlled trial. In Aim 3, we will test the efficacy of SPEAR by conducting a full-scale randomized controlled trial with 240 NPI young adults with high AUD risk in two large NPI communities in Los Angeles County and Northwest Arkansas for generalizability. Aligning with community research principles, we will share study findings with the NPI community through public reports and presentations, and to the scientific community through academic presentations and manuscripts.

NIH Research Projects · FY 2025 · 2023-09

Project Summary/Abstract Glioblastoma (GBM) is one of the most prevalent and challenging cancers to cure. Each year, nearly 12,000 new cases of GBM are diagnosed in the US, with the overall median survival being only 12 to 18 months. GBM rarely metastasizes to other organs; however, there is no effective treatment for GBM tumors. Standard therapies with surgery combined with adjuvant radiation and FDA-approved drugs can add a few months to median survival but cannot prevent the recurrence of GBM. For recurrent GBM (rGBM), prognosis is even more dismal. Repeated surgery is often not recommended since patients have already gone through it during the treatment of initial GBM, and the efficacy of other treatment options is very limited. Laser interstitial thermotherapy (LITT) is an emerging technique for minimally invasive treatment of rGBM. By introducing a slender laser probe into a brain tumor, LITT can ablate the tumor tissue percutaneously using laser radiation. However, existing LITT devices which often set the tip of a laser probe at the core of the tumor are inadequate to achieve conformal ablation (i.e., ablation with the maximum tumor coverage and minimum collateral damage), especially when tumors are large, irregularly shaped, or multifocal. Hence, to achieve conformal ablation and improve the efficacy of LITT, we propose a novel robot to deliver thermal radiation at multiple locations inside a brain tumor. We will develop a novel steerable laser interstitial thermotherapy (SLIT) robot with a slender footprint and a custom- designed flexible laser ablation probe. We will introduce SLIT to the peripheral of a brain tumor through a small burr hole, manipulate SLIT around critical structures, and perform ablation at targets that are planned by clinicians under the guidance of magnetic resonance imaging (MRI). All aspects of new procedure will be remotely monitored and controlled by clinicians using intra-operative MRI and thermometry (MRT) to ensure precision and safety. In this project, we will 1) Design and develop an MR-compatible steerable robot with a flexible ablation probe, 2) Develop software that enables planning and control of multi-site tumor ablation, and 3) Evaluate the safety and functionality of SLIT using clinically relevant models. We have formed a multidisciplinary team with expertise in minimally invasive surgical robots, biomedical fiber lasers, neurosurgery, neurosurgical devices, neuropathology, advanced MR imaging, animal models, and neuroradiology to successfully conduct the proposed studies. LITT for rGBM therapy will serve as a model for technology development, while the outcome will generate a transformative platform with applications to many neurosurgical procedures that require dexterous minimally invasive access to brain lesions.

NIH Research Projects · FY 2024 · 2023-09

Temporal lobe epilepsy (TLE) represents 60% of all epilepsy cases and involves the hippocampus resulting in memory and cognitive deficits. Within the hippocampus is the dentate gyrus (DG), a selectivity filter which generates unique representations of contextually similar inputs, a process known as pattern separation. Pattern separation relies on the coordinated activation of multiple types of interneurons (INs) which, in TLE, are susceptible to cell death and reorganize. Without proper inhibition, granule cells (GCs), the main projection neuron, fire imprecisely leading to failure in pattern separation. Two important IN subtypes in the DG are the parvalbumin (PV) INs, which modulates GC firing by delivering reliable perisomatic inhibition thus affecting output signals, and the somatostatin (SOM) INs, which modulates incoming signals by synapsing onto the distal dendrites. However, their individual contributions to pattern separation computation have yet to be determined. Recently, the semilunar granule cells (SGCs), an excitatory neuron identified by their wide dendrites, has been hypothesized to aid in maintaining suppression of the non-firing GCs. How SGCs and GCs differ in molecular and connectivity profiles is currently unknown. Interestingly, SGCs have been shown to be the primary source of perisomatic excitation onto PV-INs, potentially enhancing feedback inhibition onto local GCs. However, how SGCs affect network activity and their contribution to pattern separation in TLE is unknown. I hypothesize that SGCs will show reduced intrinsic pattern separation compared to GCs and that SGC driven PV-IN activity more robustly supports pattern separation than feedback dendritic inhibition by SOM-INs. Furthermore, experimental TLE will disrupt the precision of SGC to PV/SOM-IN mediated inhibition resulting in pattern separation deficits. This proposal will investigate the unique connectome of SGCs and, using an ex vivo temporal pattern separation paradigm as well as a in silico DG network model, to elucidate the contributions of PV-INs and SOM-INs to pattern separation in SGCs and GCs in healthy and epileptic circuits. Together, identification of the local circuit mechanisms underlying dentate pattern separation and how it is impaired during epileptogenesis will pave the way for novel strategies to manage memory related co-morbidities in epilepsy.

NIH Research Projects · FY 2025 · 2023-09

Glycolipid biointerface to decipher disease-implicated ganglioside-protein interactions All cells in the human body, including neurons, immune cells, epithelial cells, and blood cells, are coated with a dense layer of glycoproteins and glycolipids known as the glycocalyx. The extraordinary complexity in structural organization and biosynthesis of the glycocalyx has made it very difficult to comprehend the precise roles it plays in various cellular processes and thus limited its potential as therapeutic target. An important family of molecules of the glycocalyx is gangliosides, which participate in a wide array of intercellular events such as modulating killer cell toxicity, controlling neural regeneration, and promoting cell adhesion during inflammation. Gangliosides are found to play important roles in altering and mediating affinity properties of the membrane proteins in certain cancers, and are clearly implicated in insulin-resistant type 2 diabetes. However, the biochemical mechanisms of gangliosides’ effect on tumor and type 2 diabetes appear to be extremely complex, and a major portion of ganglioside pathology remains elusive. Lack of suitable techniques is a main obstacle that has principally limited the research on gangliosides and restricted our ability to understand their roles on protein function. We propose to build a highly effective, glyco-diverse, biomimetic membrane interface system and a new bioanalytical platform to study the ganglioside-protein interactions implicated in several diseases at the molecular level. A ganglioside library will be created for construction of interface mimics with precisely controlled glycan moiety, composition and packing biophysics as observed in those disease states. The proposed approach bypasses complex endogenous synthesis of gangliosides, and creates a novel hosting environment with programmed tuning in ganglioside makeups for elucidating structure- function relationships with the membrane proteins. The effect of gangliosides on protein interactions will be primarily investigated by surface plasmon resonance (SPR) spectroscopy, which quantifies molecular binding and affinity changes under systematically varied composition and headgroup moiety (Aim 1). We will then study and understand the inhibitory/promoting function of gangliosides on proteins EGFR and VEGFR, angiogenic activators linked to progression of cancer (Aim 2), and on interactions of insulin, insulin receptor and caveolin-1 (Aim 3), a key system implicated in insulin-resistant type 2 diabetes.

NIH Research Projects · FY 2025 · 2023-09

Project Summary/Abstract Over the next 5 years, NanoSMS will be developed into a technology which offers the first look into the single cell secretome; with single molecule sensitivity. The development of this new technology is based on the integration of single cell encapsulation technologies with nanopore- based single molecule sensing. The collection of molecules released into the extracellular environment by single cells, termed the single cell secretome, offers a unique glimpse into the complexities of cellular life and cell-to-cell communication. The key features of the technology which will be developed at the end of the project period include (1) a massively parallel way to form droplets adhered onto a glass slide and containing a single cell, and (2) a nanopore-based approach for measuring secreted molecule originating from a single cell. Once the nanopores and related methodologies are developed, we aim to answer four key questions surrounding important biomedical issues. First, the nanopore will quantify single cell antibody production originating from human plasma cells which have been isolated from patients in various disease states including auto-immune disorders. Second, B cells and T cells will be co-incubated and stimulated with a single antigen to induce an immune response. The time lag to start generating antibodies as well as the factors which influence the timing of the immune response will be studied. Third, eosinophils co-incubated with a single cancer cell (or cancer-derived vesicles) will be investigated to provide insight into early cancer recognition mechanisms. Lastly, single cell secretome fingerprinting will be used to access the ability to discriminate between stem cell lineages in a non-destructive manner. Stem cell characterization is important for cell therapy (in which the mechanism of action is secreted molecules) as well as assessing cell state for regenerative medicine. Needless to say, the secretome plays a functional and yet obscured role in both normal and diseased cellular states. The application of NanoSMS (a nanopore-based approach towards secretome analysis) will provide a unique and new tool for single cell characterization.

NIH Research Projects · FY 2025 · 2023-09

Small molecule detection is central in many biological, medical, and legal domains, including basic research, clinical diagnostics, environmental monitoring, and workplace drug testing, among other applications. The most widely deployed diagnostics are immunoassay-based that utilize antibodies raised against ligand-protein conjugates. These easy-to-use assays enable applications as diverse as point-of-care diagnostics, in-home testing, and real-time environmental monitoring in the field. Although small molecule immunoassays are powerful, they are time-consuming and costly to develop because analogs of target molecules suitable for conjugation to immunogenic carrier proteins must be chemically synthesized. New methods that enable the routine creation of small molecule sensors using native molecules would radically increase the speed and decrease the costs required to develop new diagnostic tests. The proposed work addresses this by building a technology that will make developing new small molecule biosensors as easy and reliable as developing new antibodies. We will accomplish this using a versatile new sensing scaffold – the plant abscisic acid receptor PYR1. This receptor participates in chemical-induced dimerization with its binding partner, HAB1. We recently described a directed evolution pipeline for creating PYR1/HAB1 dimerization (PAIR) sensors and have created sensors for 116 small molecules, including Δ9-THC, 20 FDA-approved drugs, and dozens of natural products. These sensors can be used to create ligand-regulated genetic circuits, drive ligand-mediated reconstitution of split enzymes, and rapidly create sensitive diagnostic tests. While our platform is powerful, improvements in hit rate, throughput, and the chemical space it can access are needed to empower high-efficiency sensor development; to achieve this, we will combine strain engineering, high-throughput screening, and computational design. Our improved pipeline will be used for 1-step isolation of >1000 moderate-affinity sensors of FDA-approved drugs and other medically-relevant small molecules. 100 of these will be evolved to high-affinity (nM) sensors by subsequent rounds of directed evolution. In parallel, we will develop methods for converting these sensors into multiplexable diagnostics. The technology developed will deliver new tools and methods for developing sensors of user-specified molecules and open the door to user-specified chemical-regulated processes, will have broad biomedical relevance and will advance biomedical research and clinical and environmental diagnostics.

NIH Research Projects · FY 2024 · 2023-08

With their unrivaled ability to reach youth, school-based services and primary care clinics (PCC) are ideal hubs to provide mental health healthcare, social services, and prevention to students and families. Using Participatory Design and Community Partnered Participatory Research (CPPR), UCLA and UCR psychiatry research centers with Los Angeles Trust for Children’s Health aim to: (1) Use community participatory informatics to co-design a mental health digital tool called Connected for Wellness, to support mental health navigation, linking youth to a range of mental health services, app-based evidence-based prevention resources, and other school, clinic, community, and social supports; (2) Integrate mental health self-assessments and predictive algorithms in Connected for Wellness to individualize app resources, optimize engagement and recommendations for addressing mental health and social needs; (3) Using a stepped wedge design, test the implementation of the app supported by mental health navigation models (peer navigators, family navigators) for improving connections, access to prevention resources, screening, mental health services and social supports, for youth and families. This project will be initiated with youth 13-22 years old and family and community members across 10 Los Angeles County Schools and 10 Riverside County primary care clinics. Mobile technology approaches are gaining empirical support and hold great potential for strengthening mental health navigator models. Incorporating scalable digital health tools, to aid in the mental health supports and navigation process, connecting to care, and multi-level communication, will help ensure youth are receiving optimal care that navigators, providers and other relevant systems can measure. A successful outcome of the project is a CPPR developed mobile application intervention implementable in school-based and primary care services, for improving mental health services access and prevention resources for youth.

NIH Research Projects · FY 2025 · 2023-08

PROJECT SUMMARY Sensory representations are influenced by an animal’s external context, internal state, past experiences, expectations, and future goals. Prior information – including the history of recent stimuli, actions and rewards – plays an important role in guiding ongoing behavior, and can modulate the neural code even at the level of primary sensory cortex. The involvement of sensory cortex in mediating history- dependent shifts in behavior, and the contributions of specific cell types to these effects are not well understood. Using a novel whisker-based behavioral paradigm, I have demonstrated that mice can flexibly and selectively enhance sensory processing of recently rewarded whisker stimuli based on history cues. Here, I propose experiments to uncover the cell type-specific mechanisms in for history-based modulation in primary somatosensory cortex (S1), and test for their causal role in behavior. In Aim 1 (K99), I will use behavioral modeling approaches to systematically quantify history-based perceptual biases during goal-directed behavior in mice. I will examine modulation of pyramidal (PYR) cell activity in S1 of behaving mice while tracking trial-by-trial behavioral shifts in sensory detection performance guided by recent history. I will then empirically test the necessity of S1 in mediating history effects on behavior using reversible inactivation techniques. Two cortical interneuron classes, namely VIP cells and NDNF cells, are widely theorized to play a role in selective enhancement of sensory processing in cortex, since they receive a wide range of glutamatergic and neuromodulatory inputs and boost sensory responses in PYR cells through local disinhibition. Both these cell types are activated in different active behavioral states and learning contexts. In Aim 2 (K99/R00), I will test the role of VIP and NDNF interneurons in gating history-related signals using 2p imaging to monitor their neural activity, and through targeted activation or inactivation of these cell types using optogenetic techniques. VIP and NDNF interneurons are both recruited by acetylcholine, a neuromodulator that is necessary for stimulus-specific enhancement of sensory processing in primates, and behavioral state-based modulation of sensory cortex in rodents. In Aim 3 (R00), I will test the role of basal forebrain cholinergic projections in conveying history-related signals to S1. I will perform two-photon imaging of cholinergic terminals in S1 and use selective optogenetic activation to test whether the locus of prioritized processing on the whiskers can be artificially shifted in behaving mice. Together, the proposed studies will provide new insights into the local cortical circuits that facilitate prioritized processing of behaviorally relevant stimuli in sensory maps.

NIH Research Projects · FY 2025 · 2023-08

ABSTRACT There are fundamental gaps in our understanding of how genome-wide functional genetic variation in host-parasite interactions is shaped by natural selection, including for humans. Parasitic helminths (including nematodes) present important selective agents on host traits and underlying genetic variation. Geographic clines in infection pressure, as helminths are ectothermic (temperature-sensitive), may drive genomic and phenotypic variation across host populations. This, in turn, may influence parasite adaptation. However, mechanistically linking agents of selection with targeted traits and their underlying genetic architecture in hosts and parasites remains formidably challenging. Only when resolved, will we understand how selection drives evolution of host resistance and immune system suppression and evasion by parasites. The investigator’s long-term goal is to gain mechanistic understanding, including of the genetic architecture of key host and parasite traits. The laboratory’s five-year objective is to identify these key traits, investigate their genetic basis, and functionally verify genetic variants regulating them. The core hypothesis is that coevolving hosts and parasites exert selection, pressuring one another to adapt through genetic and phenotypic changes. The rationale is that populations of plants and their nematode parasites, as genetically tractable model systems, show spatial and temporal variation in infection rates, which has a genetic basis, allowing comprehensive mechanistic studies of this issue. Working off the investigator’s prior research and robust preliminary data, this hypothesis will be tested through: 1) identifying genome-wide changes underlying geographic variation in plant resistance to nematode parasitism, and 2) determining genetic mechanisms and constraints underlying host resistance-breaking in nematodes. An evolutionary systems biology approach will identify genes, genetic networks and genomic variants underlying adaptive traits. This will be combined with parasite resurrection ecology and experimental evolution to study real-time evolutionary change. The investigator showed previously that such approaches will successfully identify key traits and genes involved in species interactions. Molecular genetic experiments will link candidate adaptive genetic variants with functional traits and fitness. This innovative research program will form a key step toward integrative comprehension of how host-parasite interactions are shaped by selection on phenotypic and genome-wide genetic variation. It holds promise for uncovering general principles relating to how host-parasite interactions evolve, helping predict sustainability of human interventions in shaping such interactions towards better outcomes for humans.

NIH Research Projects · FY 2024 · 2023-08

Rational PROTAC design enabled by integrated in silico molecular modeling and in vitro biomimetic affinity assessment Proteolysis targeting chimeras, or PROTACs, have received considerable attention in recent years as a new class of drugs as compared to traditional inhibitors. These small molecules target selective degradation of proteins of interest utilizing cell’s native protein degradation machinery including proteosomes and lysosomes. The benefits of PROTACs stem from an entirely different paradigm of protein targeting, which provides a unique path to target previously “undruggable” proteins and allows for smaller doses and thus lower side-effects. However, the complex mechanism of action has left a large knowledge gap towards the understanding of molecular interactions in different stages, especially on factors that control and stabilize the ternary complex that leads to ubiquitination and removal. In addition, existing technology lacks of strategies to model and confirm the linker region of the PROTAC for their roles in affecting the affinities of the warheads and contributing to the stability of the complex. There has been no report that includes the dynamic membrane in molecular recognition modeling. A new technical platform that can identify key parameters that impact formation of stable ternary complex and has the capability of screening molecular interactions with detailed information on structural insights is highly desired. To fill the unmet need, we propose to develop a collaborative work plan via a combination of in silico modeling and in vitro surface plasmon resonance (SPR)-based affinity assessment. We aim to identify features that lead to formation of stable ternary complexes for efficient PROTAC design. To establish and prove the technical feasibility, we will study anaplastic lymphoma kinase (ALK), a transmembrane receptor tyrosine kinase that is an important drug target for a variety of cancers, and an E3 ligase CRBN which has been used to promote protein degradation. Specifically, we propose three aims: Aim 1. Establish a molecular modeling platform for rational PROTAC design. The platform incorporates protein dynamics and inputs from experiments and can adapt various experimental settings such as membrane environment used in SPR. Aim 2. Build and characterize modeled PROTACs and biomimetic membranes. This includes generating PROTAC-compatible membrane mimics and structural characterization of the interfaces for membrane-bound proteins for SPR analysis. Aim 3. Investigate interaction properties of PROTAC candidates’ in biomimetic membranes. This includes on-line in vitro experiments and screening for the PROTACs at stabilizing the ternary complexes. The identification of stable PROTAC complexes will be used into further exploration into the understanding of the structure-function relationship of the system.

NIH Research Projects · FY 2025 · 2023-08

PROJECT SUMMARY Histone chaperones are functionally and structurally diverse proteins. They play a central role in chromatin organization and maintenance by binding to histones and facilitating nucleosome assembly during DNA replication, transcription, recombination and repair processes. Moreover, some histone chaperones evolved additional functions independent of histone binding. Histone chaperones are thus essential for cellular proliferation and organismal development. Intriguingly, circumventing this lethality in a number of cell fate change paradigms revealed roles of histone chaperones in cellular plasticity. For example, we and others have shown that the chromatin assembly factor 1 (CAF-1), a histone chaperone complex involved in replication dependent nucleosome assembly and heterochromatin regulation, prevents cellular reprogramming. More recently, we demonstrated that CAF-1 maintains lineage integrity of stem and progenitor cells by repressing the transcription of differentiation genes. In this context, CAF-1 controls chromatin accessibility at enhancer/promoter elements of lineage specific loci and prevents aberrant binding of transcription factors. In addition to these CAF-1 sensitive sites, we also identified heterochromatic loci whose accessibility is perturbed upon CAF-1 loss, albeit with unknown effects on cell fate. The influence of CAF-1 on local euchromatic and heterochromatic loci is intriguing given that CAF-1 acts in a sequence independent manner to assemble nucleosomes during DNA replication. Whether such profound effects of CAF-1 on cell fate are linked to its nucleosome assembly function or additional non-canonical functions remain unexplored. Moreover, given the growing repertoire of histone chaperones and associated histone variants, it remains unclear whether CAF-1 cooperates with other histone chaperones to maintain lineage integrity. Therefore, the functional and structural determinants of the histone chaperone network as a whole in the context of cell fate remain important open questions. To investigate the molecular mechanisms underlying the lineage specifying functions of histone chaperones, we will use well established cell fate change paradigms in combination with gene editing/RNAi, multi-omics, biochemical and functional approaches. Specifically, we propose the following two research directions: (1) Investigate the regulatory mechanisms and function of histone chaperone sensitive chromatin sites and, (2) interrogate the structure-function relationships of histone chaperones and how their domains are intimately linked to control cell fate. In the short-term, we plan to dissect the epigenome and structural determinants of CAF-1. In the long-term we plan to extend our analysis to other histone chaperones pathways and how they cooperate with CAF-1 to control cell fate. If successful, our studies will contribute to design strategies for manipulating histone chaperone pathways to control cell fate in health and disease.

NIH Research Projects · FY 2026 · 2023-08

Project Summary Transposable elements (TEs) are mobile genetic elements that can propagate within the host DNA and have a significant impact on the genome organization and function. TEs are ubiquitous across the tree of life and occupy substantial fractions of animal genomes - about 20% of the D. melanogaster, and 45-50% of human and mouse genomes consist of TE fragments that have accumulated throughout evolution, and active TEs are a major source of genetic and epigenetic variation. Despite their prevalence, TEs’ unusual characteristics and high copy numbers left them poorly annotated, and among the most enigmatic and understudied genetic elements. TEs are typically seen as harmful, as their mobility causes DNA damage and can impact the host genome and transcriptome by directly disrupting functional elements or introducing ectopic binding sites for transcriptional and epigenetic regulators. To prevent their deleterious activities, TEs are targeted by various silencing mechanisms. Among these, the piRNA pathway enforces transcriptional and post-transcription repression of TEs in animal germlines, which is crucial for fertility and preserving the integrity of genetic information across generations. On the other hand, TEs are an important source of evolutionary innovation and there is a growing body of literature on TE-derived regulatory regions and functional products that became incorporated into host regulatory networks. Interestingly, early embryogenesis of both vertebrates and invertebrates is characterized by a spike of TE activity, and at least in mice, timely activation of specific TEs is essential for normal developmental progression. However, the diversity of products from TEs and their functional roles in somatic cells in both systems remain poorly characterized, largely owing to long-standing technical difficulties in the genomic analysis of elements that exist in high copy numbers. The molecular mechanisms of TE regulation and the functional implications of TE activity are central areas of interest for my laboratory. I present a research program that addresses key questions within two major aspects of TE biology: 1) the mechanism and regulation of piRNA-mediated TE silencing in the germline and 2) the characteristics and functions of somatic TE expression during development, using the classic model Drosophila as a paradigm. First, I propose a focused strategy to dissect the regulation and function of several key piRNA pathway components, building on my previous findings that protein SUMOylation plays essential roles in piRNA biogenesis and TE silencing. In parallel, I plan to leverage state-of-the-art long-read and single-cell sequencing technologies to overcome historical limitations to the genomic analysis of the TE-derived transcriptome, with the long-term goal of elucidating the molecular basis and functional consequences of somatic TE activity in the developing organism.

NIH Research Projects · FY 2024 · 2023-07

Social cognition is a fundamental process essential for species survival. Disturbances in social processing have been identified by the NIMH Research Domain Criteria Initiative as a major domain disrupted across psychiatric disorders including neurodevelopmental disorders (NDDs) such as autism spectrum disorders (ASD). ASD prevalence continues to increase at an alarming rate, affecting 1 in 54 U.S. children, and characterized by an unexplained sexual dimorphism. While ASD has a strong genetic component, the disorder is in most cases, multifactorial, resulting from sex-specific genetic susceptibilities interacting with environmental factors during critical developmental periods. Thus environmental exposures, including exposures to endocrine disrupting chemicals (EDCs), may contribute to the rising prevalence of ASD. However, experimental evidence has not established a direct link with specific chemicals and mechanisms remain elusive. PBDEs are commercial flame retardants found in human breast milk that are associated with developmental deficits in children. Our lab has shown that the commercial PBDE mixture, DE-71, produces ASD-relevant phenotypes that include deficient social recognition memory, exaggerated repetitive behavior, and altered neuromolecular profiles for the social neuropeptides, oxytocin (OXT) and vasopressin, and their receptors. PBDEs structurally resemble thyroid hormones (TH), which are both critical for neurodevelopment of social brain circuits and regulate OXT and AVP. Therefore, I will test the novel hypothesis that developmental PBDEs produce a hypothyroid state, which disrupts signaling in the central OXTergic system and malformation of social neural circuits leading to deficient socioemotional behavior. In mechanistic studies under Aim 1, I will examine the TH targets of PBDEs and the contribution of TH disruption to altered behavior and neuropeptide phenotypes of PBDE-exposed male and female offspring using maternal thyroid supplementation. Chemogenetic activation of OXT release within the PVN will be employed in an attempt to rescue PBDE-induced abnormal phenotypes. In circuit-level studies using retrograde tract-tracing under Aim 2, I will examine PBDE reprogramming of the reciprocal preflimbic cortex to basolateral amygdala circuit, which is critical for social recognition ability. Since this circuit depends on OXT receptor (OXTR) signaling and is purported to receive OXTergic projections from PVN, I will determine if developmental intranasal OXT rescues structural changes produced by PBDEs. These studies will investigate the neurodevelopmental effects of maternal transfer of PBDEs across multiple levels of biological organization and developmental ages to begin to understand mechanisms and critical windows of risk. My findings will provide critical mechanistic information necessary to break through gaps in knowledge about the possible environmental risk to NDDs. They will also inform about the role of oxytocin underlying social and emotion recognition behavior and the mechanisms altering circuit-level function during neurodevelopment. Finally, the findings may eventually translate to the development of alternative therapeutic approaches to treat psychosocial NDDs.

NIH Research Projects · FY 2026 · 2023-07

This study will target a critical knowledge gap in our understanding of the neural mechanisms underlying upper limb poststroke spasticity, by directly assessing the descending motor and ascending sensory pathways in hand function. Spasticity is one of the major motor impairments after stroke that typically begins to emerge several weeks poststroke, impedes upper limb functional recovery, and gives rise to complications such as weakness, contractures, and pain. It is traditionally characterized by a velocity-dependent increase in muscle tone (hypertonia) and increased spinal stretch reflex (hyperreflexia). Although the peripheral and spinal signatures of spasticity have been extensively studied, its underlying brain mechanisms and brain-spinal pathways are still controversial. This understanding is critically needed for resolving the current limitations in clinical management of spasticity related to its early diagnosis, identification of prognostic factors, and lack of effective treatments targeting the origin of the impairments rather than its symptoms. Preclinical studies have shown that lesions of descending motor pathways including the reticulospinal tract (RST) may lead to spastic hypertonia after stroke. In contrast, changes in the spinal sensory-motor circuits and the ascending sensory projections may underlie hyperreflexia after stroke. Yet it is unclear how brain lesions after stroke lead to these remote changes in the spinal cord circuit. Several theoretical models backed by early electrophysiological work in cats propose that an imbalance of inhibitory and excitatory projections from the dorsal and medial RST plays a critical role in spasticity. However, emerging evidence in primates suggests that the type of RST projections (inhibitory/excitatory) does not follow a dorsal/medial organization, as presumed in current models of spasticity, but depends on the laterality of projections. In this proposal, we aim to translate these new findings to humans, and examine their relevance in poststroke spasticity. Our central hypothesis is that in stroke survivors with spasticity, the imbalanced activation of ipsilateral vs contralateral RST is directly related to spastic hypertonia, while the hyperactivity of dorsal column somatosensory projections is related to spastic hyperreflexia. To test this hypothesis, we will employ a powerful neuroimaging method using simultaneous spinal cord–brain functional magnetic resonance imaging (fMRI) in chronic hemiplegic stroke patients with and without upper limb spasticity, as well as healthy controls. Using this method, we will assess the function of major descending (corticospinal, RST) and ascending (dorsal column, anterolateral tract) pathways during hand motor and sensory functional tasks. We will determine how these neuroimaging markers relate to spastic hypertonia and hyperreflexia, as evaluated by reliable biomechanical and electrophysiological measurements. Overall, the proposed projects will advance our understanding of the neurobiological basis of poststroke spasticity, offer new quantitative neuroimaging markers for accurate prognosis of spastic complications, and provide outcome measures for evaluating what treatments most directly target the neural origins of spasticity.

NIH Research Projects · FY 2026 · 2023-06

Project Summary Atherosclerotic cardiovascular disease (CVD) is the leading cause of mortality and morbidity worldwide and recent large-scale human studies have implicated a link between exposure to endocrine disrupting chemicals (EDCs) and CVD. However, how exposure to EDCs and other environmental chemicals influences CVD risk is still poorly understood, and continues to hamper assessment of the health risks of EDC exposure. With the NIEHS funding support, we have identified many EDCs as potent agonists of the xenobiotic sensor pregnane X receptor (PXR). The identification of EDCs as PXR ligands has provided an important tool for the study of new mechanisms through which EDC exposure impacts disease. Our laboratory was the first to reveal the novel function of PXR in the regulation of atherosclerosis development, and has also demonstrated that widely-used EDCs including bisphenol A, dicyclohexyl phthalate, and tributyl citrate increase atherosclerosis and dyslipidemia through PXR signaling in various mouse models. Influences of the chemical environment on human health have become the subject of intense interest but very few studies in the EDC research field have focused on atherosclerosis development. My diverse scientific training in molecular biology, toxicology, pharmacology, and cardiovascular research has put me in a unique position to investigate how “gene-EDC interactions” affect atherosclerosis development and lipid homeostasis. This EDC-Induced CVD Revolutionizing Innovative, Visionary Environmental health Research Program (EICVD-RIVER) will allow me to investigate the broad scientific theme of the impact of EDC exposure on lipid homeostasis and atherosclerosis in adults and their offspring. EICVD-RIVER will address the following specific scientific questions: 1) How many common chemicals in plastic and other consumer products act as EDCs to modulate PXR activities? Can different EDC mixtures synergistically activate PXR? 2) Through which cell-specific mechanisms do EDCs induce dyslipidemia and atherosclerosis? 3) How does PXR regulate ceramide homeostasis to affect EDC- induced atherosclerosis? 4) Do microplastics have a Trojan Horse effect on EDC-induced atherosclerosis? Can they bring EDCs intracellularly to have synergistic or additive impact on PXR-mediated atherosclerosis? 5) Does paternal exposure to PXR agonistic EDCs affect the atherosclerosis development of the offspring? How does PXR signaling alter the sperm RNA code to increase CVD risk of the offspring? The proposed studies will contribute to our understanding of gene-EDC interactions in predisposing individuals and their offspring to CVD, and my expertise and experience are an ideal fit for the RIVER mechanism that supports a multi- dimensional long-term study of the proposed research.

NIH Research Projects · FY 2026 · 2023-06

Project Summary The University of California Riverside (UCR) is one of the most diverse campuses in the nation and is in one of the most rapidly growing and diverse regions of the U.S. Most undergraduate students at UCR come from this region and are from underrepresented groups in the sciences. Thus, there is a broad base of underrepresented (UR) students from which to select and promote interest in a research career in biomedical or behavioral sciences. The main goal of the MARC Program at UCR is to increase the number of UR students pursuing PhD degrees and research careers in the biomedically-related sciences. This training grant provides a summer Pre-MARC Development Program (9-10 students/year) to increase the eligible pool of students for the research Trainee Program (16 positions/year; 2-3 years of training). The Objectives of the Program are: (1) Increase the number of UCR minority students majoring in the sciences who are qualified to become MARC Trainees through outreach to local high schools and community colleges. (2) Increase the number of qualified students who apply to the MARC Program by using freshman courses and discovery seminars, by synergizing with Honors and existing Minority programs on campus, and by engaging students in Pre-MARC undergraduate research before their sophomore year and stimulating their interest in a biomedical research career. (3) The core of the program is preparing the MARC Trainees for graduate studies in highly competitive research institutions. We will achieve this by immersing MARC Trainees in intensive cutting-edge research in laboratories of Faculty Mentors on campus during the academic year and in one other off-campus laboratory at a high-caliber research institution during one summer; we will also provide specific classes that will prepare the Trainees to think critically, to design and implement rigorous and ethical experiments, to learn modern research methods, to write scientific reports/papers and fellowships, and to be efficient communicators in front of expert and lay audiences. Guidance in applying to graduate programs will be provided. This will give self-confidence and prepare the trainees to enter and succeed in the most competitive graduate programs in the U.S. This program is for 5 years and proposes to train about 48 MARC students with the goal that about 80% of them will succeed in entering high quality PhD or MD/PhD programs in the biomedical sciences. Relevance: This MARC training grant will not only contribute to increase the number of UR biomedical scientists but should also have broader impacts. MARC Scholars will be role models that inspire new generations and help break down discriminatory barriers.

NIH Research Projects · FY 2024 · 2023-06

The exponential surge in the prevalence of neurological diseases/disorders, partly due to the rapid growth in the aged population, poses a significant challenge to the prevention and treatment of impairments in cognitive, sensory, and motor functions. However, our insufficient understanding of the mechanisms underlying the pathogenesis of many neurological diseases delays the development of effective treatments to address this challenge. Recent advances in optogenetics have provided novel tools to investigate complex neural circuits and brain functions. Due to a limited penetration depth of photons, however, the invasiveness of light sources into the brain tissue of live animals to control opto-sensitive ion channels has been one of the major challenges in optogenetics. In this regard, our goal is to develop a modular mechanoluminescent (ML) material platform for the non-invasive, acoustic activation of various optogenetic channels for neural modulation with a high spatiotemporal resolution. This project builds upon our recent technological achievements, in which we developed various synthesis methods to produce novel structures of inorganic nanomaterials and high piezoelectric organic nanofiber fragments. Based on our preliminary computational modeling, we hypothesize that such structures enable greater effective strains that maximize the ML performance of the inorganic-organic hybrid nanomaterials. This project aims to develop two unique optogenetic modulation systems based on ML nanomaterials. In Aim 1, we will synthesize zinc sulfide nanoparticles doped with various metal ions to control emission wavelengths and investigate the effect of nanoparticle morphology and dimension on ML performance. Furthermore, the interaction between those nanoparticles and encapsulating polymer will be optimized to maximize the ML performance of nanocomposites. In Aim 2, we will characterize the piezoelectric properties of electrospun fiber-derived nanofragments and investigate the incorporation of ML nanoparticles into the piezoelectric nanofragments to boost ML performance. An in vitro model based on a neural stem cell line transduced with Channelrhodopsin-2 will be utilized to determine the performance of these ML nanomaterials for neuromodulation. Overall, we anticipate that these studies will provide material bases for ML nanoparticles injectable into the circulatory system (Aim 1) and for ML nanofragments injectable into a site of interest (Aim 2). The results of this exploratory project are expected to identify candidates for ML nanomaterial platforms for further optimization and animal testing in subsequent studies.

NIH Research Projects · FY 2026 · 2023-04

PROJECT SUMMARY The secretory pathway must fold and traffic one third of the proteome, while handling an exceptional dynamic range of client load. Quality control mechanisms prevent proteostasis in the secretory pathway from being overwhelmed by proteins in non-native states. One such mechanism is preemptive quality control (preQC), wherein ER stress inhibits ER translocation of nascent proteins. This process protects the ER from being overwhelmed with nascent protein during misfolded protein stress, a situation associated with diverse disease included diabetes and neurodegenerative diseases. However, this protection leads to secretory protein accumulating in the cytosol, which can be proteotoxic and lead to cell death and dysfunction. Due to methodological limitations, the substrates, causes, mechanism, and consequences of preQC are largely unknown. Hence, the physiological relevance of preQC, while expected to be significant, is not well understood. We propose to apply our recently developed assay for secretory protein mistargeting to systematically characterize preQC. We will identify which stresses induce preQC for a series of protein substrates in secretory cells from diverse human lineages. We will identify what factors govern triaging of mistargeted secretory proteins between aggregation and degradation mechanisms. Because our assay is performed in living cells, we will determine which signaling pathways mediate induction of preQC by ER stress. Finally, we will extend our assay to allow proteome-wide quantification of both basal and stress-dependent ER mistargeting. This extension will allow us to identify the factors that govern susceptibility of proteins to preQC. The outcome of the proposed research will be systematic characterization of how the cell remodels ER translocation in response to stress.