University Of Southern California

NIH Research Projects · FY 2025 · 2011-08

The movement of 90-90-90: Treatment for All aims to end the AIDS epidemic by 2030; however, there were still 1.7 million new HIV infections in 2019 worldwide, emphasizing the need to improve current systems of HIV epidemic monitoring and targeted preventions and interventions. As a renewal application of the parent R01 project (AI095066), this proposal builds upon our pioneering accomplishments of inventing microdrop HIV sequencing for high-resolution and low-cost simultaneous HIV incidence and drug resistance surveillance. Our single blood draw assay approach, HIDA (HIV Incidence and Drug Resistance Assay), responds to the growing need to precisely determine HIV incidence and identify drug resistance mutations, including minority variants and cross-class drug resistance mutations linked in a single genome. Our major innovation is to amplify HIV full- length envelope and pol gene sequences within micro-droplets and this compartmental amplification alongside with long-read high-throughput sequencing allows us to extract incidence and drug resistance signatures in a highly precise manner. The central goal of this application is to deliver an end-to-end platform for real-time HIV incidence and drug resistance cross-sectional surveillance. In Aim 1, we propose to conduct a cross-sectional surveillance by accessing 2,658 HIV positive plasma specimens from the Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS), in partnership with Nigeria CDC. By producing massive HIV full-length envelope and pol gene sequences, we will report Nigeria’s regional HIV incidence profiles and 93 WHO surveillance drug resistance mutation prevalence at the population and individual levels. Aim 2 of this application is devoted to devise a low- cost, open-source laboratory automation platform. Recent advances in do-it-yourself automation platforms will facilitate the deployment of HIDA’s microdrop HIV sequencing into low- and middle- income countries for their perpetual HIV surveillance. This standardized, high-throughput automation platform is ideal for performing cross- sectional surveys in resource-limited settings. Aim 3 will integrate HIDA with a cloud-based platform that fully automates incidence and drug resistance surveillance algorithms as a software-as-a-service. The standardization of high-throughput sequencing data analysis is a central requirement for routine surveillance. HIDA’s software- as-a-service will output standardized, high-quality surveillance outcomes directly to users, circumventing the need for investigators to invest in high-cost hardware to perform their own time-consuming analyses. This cloud platform will report both population-level and individual-level incidence and drug resistance profiles in a given geographic region. HIDA via microdrop HIV sequencing will promote global real-time surveillance by serving as a precise and high-throughput cross-sectional survey tool for incidence and drug resistance.

NIH Research Projects · FY 2025 · 2011-07

The future of dental education and support for biomedical research require investment in the selection and training of tomorrow's scientists, including basic, translational and clinical researchers. One of the stated goals of the NIDCR is to “ensure that a diverse network of highly trained scientists is available in appropriate scientific disciplines to address the Nation's biomedical, behavioral, and clinical research needs”. In an effort to achieve this goal, we are seeking renewal of our NIDCR-sponsored Institutional Training Program in Oral Health Research, which provides an array of training opportunities in craniofacial health research. This grant thus requests support to provide education and intensive, integrated research training for a select cadre of scholars seeking either a PhD degree or postdoctoral training (for both DDS/MD and PhD graduates) with a major focus on dental, oral and craniofacial health and disease. Only the most highly qualified and motivated predoctoral and postdoctoral candidates will be selected for T90/R90 support. The T90 and R90 award components will allow us to continue to train U.S. citizens and permanent residents as well as non-permanent residents, who bring a global perspective. International scholars, clinician-scientists and underrepresented minorities have made, and will continue to make, significant contributions to dental and craniofacial research and teaching, serving as outstanding role models. We will continue to emphasize selection of qualified, exceptional candidates from underrepresented backgrounds to further enhance diversity in the biomedical workplace. At a time when inclusion and understanding have never been more important, fostering a diverse cohort of academic researchers is a core component of our mission to prepare this next generation of leaders. Outstanding predoctoral and postdoctoral trainees will be interviewed and chosen by an Internal Steering Committee (ISC) for an initial 12-month period of support, and provided they demonstrate satisfactory progress, will be awarded support for another 12 months. Program oversight will be from the Principal Investigator and Co-Investigator, the ISC, and an advisory External Steering Committee (ESC). Trainee mentors will be primarily tenured faculty from either the Herman Ostrow School of Dentistry (Ostrow) or the Keck School of Medicine (Keck) of USC. Mentors have been selected using two simple criteria: 1) they maintain active research profiles and have a significant history of successful mentorship, and/or 2) they have current independent research funding from the NIDCR, which serves as a strong indication that their research interests are in alignment with the stated goals of the NIDCR. During the T90/R90 appointment period trainees will enroll in grant writing classes, attend seminars and workshops, and submit a competitive peer-reviewed grant application. Both Ostrow and the Provost's Office at USC remain fully committed to this and similar federally supported NRSA training grants, and will ensure that additional financial support is in place to achieve all stated outcomes.

NIH Research Projects · FY 2025 · 2011-07

PROJECT SUMMARY / ABSTRACT The future of dental education and support for biomedical research require investment in the selection and training of tomorrow's scientists, including basic, translational and clinical researchers. One of the stated goals of the NIDCR is to “ensure that a diverse network of highly trained scientists is available in appropriate scientific disciplines to address the Nation's biomedical, behavioral, and clinical research needs”. In an effort to achieve this goal, we are seeking renewal of our NIDCR-sponsored Institutional Training Program in Oral Health Research, which provides an array of training opportunities in craniofacial health research. This grant thus requests support to provide education and intensive, integrated research training for a select cadre of scholars seeking either a PhD degree or postdoctoral training (for both DDS/MD and PhD graduates) with a major focus on dental, oral and craniofacial health and disease. Only the most highly qualified and motivated predoctoral and postdoctoral candidates will be selected for T90/R90 support. The T90 and R90 award components will allow us to continue to train U.S. citizens and permanent residents as well as non-permanent residents, who bring a global perspective. International scholars, clinician-scientists and underrepresented minorities have made, and will continue to make, significant contributions to dental and craniofacial research and teaching, serving as outstanding role models. We will continue to emphasize selection of qualified, exceptional candidates from underrepresented backgrounds to further enhance diversity in the biomedical workplace. At a time when inclusion and understanding have never been more important, fostering a diverse cohort of academic researchers is a core component of our mission to prepare this next generation of leaders. Outstanding predoctoral and postdoctoral trainees will be interviewed and chosen by an Internal Steering Committee (ISC) for an initial 12-month period of support, and provided they demonstrate satisfactory progress, will be awarded support for another 12 months. Program oversight will be from the Principal Investigator and Co-Investigator, the ISC, and an advisory External Steering Committee (ESC). Trainee mentors will be primarily tenured faculty from either the Herman Ostrow School of Dentistry (Ostrow) or the Keck School of Medicine (Keck) of USC. Mentors have been selected using two simple criteria: 1) they maintain active research profiles and have a significant history of successful mentorship, and/or 2) they have current independent research funding from the NIDCR, which serves as a strong indication that their research interests are in alignment with the stated goals of the NIDCR. During the T90/R90 appointment period trainees will enroll in grant writing classes, attend seminars and workshops, and submit a competitive peer-reviewed grant application. Both Ostrow and the Provost's Office at USC remain fully committed to this and similar federally supported NRSA training grants, and will ensure that additional financial support is in place to achieve all stated outcomes.

NIH Research Projects · FY 2026 · 2011-05

This application is for renewal for a third cycle of a Predoctoral Training Program in Developmental Biology, Stem Cells, and Regeneration at the University of Southern California (USC). This training program has both benefitted from and contributed to the dramatic growth of stem cell biology and regenerative medicine research at USC Keck School of Medicine. The presence of a dedicated Department of Stem Cell Biology and Regenerative Medicine that has been actively recruiting new faculty, a highly successful PhD Program in Development, Stem Cells, and Regeneration (DSR) that now averages ~15 new entering students per year, and a university-wide USC Stem Cell initiative makes for a highly dynamic, ideal training environment for students. The training program is designed to provide cohesive, structured training in developmental and stem cell biology, coupled with training-grant-specific courses and activities that provide in-depth exposure to clinical problems and advanced bioinformatics. Such a program will best train a future generation of scientists that wish to apply their foundational research in developmental and stem cell biology to the field of regenerative medicine. A unique strength of this training program is that it provides added value, beyond the DSR program, in the form of clinical exposure. Each trainee is paired with a Clinical Co-Mentor, who guides the student in learning about the diseases to which their primary research relates. Trainees take a T32-specific seminar class led by clinician scientists, as well as a hands-on workshop in USC’s new GMP facility that exposes students to manufacturing of clinical-grade stem cells and gene therapy reagents. This exposure of students to how stem cells can address unmet clinical needs is aided by close ties of USC with one of the largest public hospitals in the country, and the extensive participation of clinician-scientists in all aspects of the training program. Recently, we have also partnered with the Department of Quantitative and Computational Biology to offer specialized computational biology training, in direct response to feedback from trainees. During the previous four years of the training program, the 16 funded trainees have published 30 manuscripts in journals such as Cell Stem Cell, Developmental Cell, PNAS, Neuron, and PLoS Biology, and have received four NIH F31 fellowships. Of the 30 trainees since T32 inception, 16 have graduated and 13 remain in training. All graduates have remained in science-intensive positions, with 7 performing postdocs, 6 entering industry, 3 pursuing science policy and journalism, and 1 recently accepting a tenure-track assistant professorship at UCLA. From the first to second funding period, we have increased success of NIH F31s (2 to 4), and the number of students in the main DSR feeder program (~6 to ~15 per year), while decreasing time to degree (6.5 to 5.1 years). The students have hosted a major symposium each year, including virtually during the pandemic, and we have instituted an overnight Annual Retreat as of 2019. The cohesive structure of this training program provides an extra level of clinical fluency that the trainees would not otherwise have obtained through the DSR feeder program alone.

NIH Research Projects · FY 2026 · 2010-08

PROJECT SUMMARY Kidney function is critical to maintaining effective circulating volume (ECV), electrolyte homeostasis and blood pressure (BP). Dysregulation of fluid and electrolyte transport in the kidney is central to hypertension (HTN) and cardiovascular disease (CVD) progression. Na+, K+, and volume homeostasis are maintained by regulation of renal ion and water transporters expressed in tubule specific patterns; K+ balance also depends on regulation of muscle transporters. HTN and CVD are a function of sex, age and lifestyle; less frequent in females than males below 65 yr and more common in post-menopausal females vs males over 65 yr; salt sensitivity of BP increases in both sexes with age. We have reported sex differences in the abundance of transporters along the nephron in both Sprague Dawley rats (SDR) and C57BL/6J mice, and used computational models to establish the functional implications of the dimorphisms, e.g. more robust natriuretic responses in young female vs male SDR. How kidney and muscle transporter profiles respond to life cycle transitions from development through aging and menopause is not known. Our overarching goal is to combine experimental and computational approaches to determine how kidney (and muscle) functions adapt to maintain ECV, electrolyte and fluid homeostasis in response to life cycle challenges in both male and female rats and mice: from development to aging, through the female-specific challenges of lactation and menopause, and the common challenges of dietary Na+ and K+. Aim 1. Test the hypothesis that baseline kidney function adapts during life cycle in a sex-specific manner to maintain fluid and electrolyte homeostasis. When do transporter sex differences appear? Is the more robust natriuresis in young females vs males still evident at 12 mo? Do muscle K+ transporters exhibit sex dimorphisms that impact K+ adaptation with age? We will utilize the Four Core Genotype mouse model to attribute dimorphisms along life cycle to gonadal hormones vs sex chromosome complement. Aim 2. Describe mechanisms of female kidney adaptation to lactation. Do kidney and nephron function adapt to maintain maternal homeostasis during peak lactation at minimal cost? Do kidney function, ECV and electrolyte homeostasis return to baseline after lactation cessation? Does extrarenal K+ homeostasis (skeletal muscle K+ transporters and [K+]) adapt during/after lactation? Aim 3. Test the hypothesis that menopause and age reduce sex differences and increase salt-sensitivity. Does ovotoxin-induced menopause change female kidney and muscle transporter profiles and function? Is salt-sensitive hypertension sex dependent? Exacerbated after menopause? Accomplishing these aims will fill important gaps in knowledge about sex-specific mechanisms of Na+, K+, and volume homeostasis and physiology throughout life cycle, thus, providing a better understanding of the female advantage in CVD and guiding therapeutic targets in both sexes across life cycle.

NIH Research Projects · FY 2025 · 2009-07

Project Summary In 2009, faculty at the University of Southern California (USC) who study the neuroscience of hearing and vocal communication established a research training program for pre- and post-doctoral scholars. The Hearing and Communication Neuroscience (HCN) Training Program brings together a broad spectrum of scientists to enhance inter-disciplinary communication and offers the advantage of providing research training opportunities that bridge basic science with translational research and clinical applications. The program serves to reinforce research and training interactions between scientists who study basic aspects of hearing and vocal communication in the Dornsife College of Letters, Arts & Sciences; the Keck School of Medicine; and the Viterbi School of Engineering at USC. The program combines the strengths of an outstanding group of researchers, the resources of USC graduate programs in Neuroscience, Development / Stem-Cell / Regenerative Medicine, Psychology, Linguistics, and Biomedical Engineering, as well as the excellence in clinical otology provided by the Department of Otolaryngology. The rationale of this proposal is to engage pre- and postdoctoral trainees in a highly interactive and multi-disciplinary training experience—ranging from cell biology and engineering to cognitive neuroscience and linguistics, but unfettered by conventional departmental barriers—to actively facilitate their development as independent scientists. We have successfully filled positions with outstanding pre- and post-doctoral scholars during the first fifteen years of the program. Predoctoral trainees typically join the program during the second year of their graduate training; the level of experience of post-doctoral trainees participating in the program varies. All trainees receive multi-disciplinary training in all aspects of hearing and communication neuroscience, as well as practical skills that prepare them for careers in independently funded research, education, and industry. Our demonstrated ability to expose trainees directly to cutting-edge research in basic science as well as ongoing clinicalresearch and applications is a major strength of the program.

NIH Research Projects · FY 2025 · 2009-04

APOBEC proteins, a diverse family of cytosine deaminases, are pivotal to multiple biological processes, ranging from innate and acquired immunity to cholesterol metabolism and oncogenesis. Central to their function is the ability to edit nucleic acids, a mechanism exploited to restrict viral infections, including those caused by retroviruses like HIV and certain DNA viruses. In addition, APOBECs serve as guardians against endogenous retroelements that could compromise genomic integrity. However, when their regulation falters, these enzymes can become deleterious, contributing to immune deficiencies such as hyper-IGM syndrome, genomic instability, and even cancer. In primates, the APOBEC3 (A3) subfamily consists of seven members (A3A-H), each exhibiting distinct antiviral activities. Some of these, notably the double-domain A3s, thwart HIV/SIV by deaminating viral cDNA or inhibiting its transcription through deaminase-independent pathways. Yet, the battle is not one-sided: HIV and SIV viruses counteract by deploying the Viral Infectivity Factor (Vif), which co-opts host cellular machinery to degrade A3 proteins, thus neutralizing their antiviral arsenal. Our proposal aims to dissect the intricate structural dynamics that underpin APOBEC function and regulation, particularly how these proteins engage with nucleic acids and how HIV evades their defenses. By elucidating the molecular choreography between A3s and the diverse Vif proteins of HIV/SIV, we seek not only to advance our understanding of viral pathogenesis but also to open avenues for innovative therapeutic interventions against HIV/AIDS and APOBEC- related cancers. The specific goals of this project are to characterize the interactions of nucleic acids with double-domain A3s, to unravel the mechanisms of HIV restriction by these proteins, and to understand the molecular strategies employed by Vif proteins to disable various A3s. Through these studies, we hope to uncover fundamental principles that govern APOBEC functions and their role in immune defense.

NIH Research Projects · FY 2025 · 2008-09

The USC-UCLA Drug-Induced Liver Injury Clinical Center (CC) proposal in response to RFA-DK-22-013 “Continuation of the Drug Induced Liver Injury Network (DILIN) Clinical Centers” hopes to continue to participate with the other CCs to advance the scientific knowledge and clinical evaluation of DILI. Our proposal will continue to combine the only two medical schools in Los Angeles County allowing us to be able to uniquely capture and enroll DILI cases into the Networks database supervised by the Data Coordinating Center (DCC). The 9.8 M residents of Los Angeles County (2022) are an unmatched resource composed of the most ethnically diverse population in the United States. Our proposal continues to utilize the expertise and talents from Keck School of Medicine of USC and David Geffen School of Medicine at UCLA. The enrollment of a large number of bona fide and ill patients with close follow up has demonstrated our CC’s ability to capture DILIN cases in this diverse populations with little overlap in etiology for DILI other than for herbal and dietary supplements (HDS) in our respective patient populations. The Specific Aims for the continuation of the USC-UCLA DILI CC are to: 1) Continued enrollment of high quality bona fide DILI case from under represented populations and HDS agents with proposed biospecimens collections for future studies.; 2) Specific Aim 2: Mechanism of cell death and the role of innate immunity in Immune-Mediated Liver Injury due to Checkpoint Inhibitors (ILICI) (Ancillary Study); 3) Specific Aim 3: Proposed Clinical Treatment Trial for Cholestatic and Acute Liver Injury and 4) Specific Aim 4: Continued support of the DILIN’s effort to develop causality assessment instruments and development of a pilot project for a pharmacovigilance protocol for adverse liver injury due to medication or HDS. .

NIH Research Projects · FY 2025 · 2008-09

Project Summary Understanding how visual information is processed and transformed by cortical and subcortical pathways to generate visually guided behavior is fundamental for visual research. As a critical sensorimotor center, the superior colliculus (SC) in the mammalian midbrain mediates visually guided behaviors in a context- dependent manner and holds great promise for understanding neural principles for the processing and transformation of visual signals into appropriate behavioral responses. The visuosensory layer of SC (or SCs) receives direct bottom-up relay of visual information from the retina, as well as inputs from multiple other visual structures. How the information from different sources is integrated by SCs neurons to differentially influence the processing and transformation of visual signals for context-dependent behavioral control remains largely unclear. In this project, by focusing on visual processing and transformation underlying two salient SC-mediated visually guided behaviors, defense behavior induced by high-field looming visual stimuli and approach behavior induced by low-field moving dots, we will investigate how the two major inputs of SC, the glutamatergic input from the primary visual cortex (V1) and GABAergic input from the ventral geniculate nucleus (vLGN), contribute to the shaping of SC processing. We will test an overarching hypothesis that V1 and vLGN inputs act together to regulate the gain and selectivity of visual features of SC neurons to achieve context-dependent modulation of visual behaviors. In Aim 1, we will examine how V1 input modulate visual response properties of SCs neurons in a lamina-dependent manner and how it contributes to selection of defensive reactions in response to high-field threatening visual stimuli though eliciting competitive interactions between SCs subcircuits. In Aim 2, we will examine the functional role of vLGN input in modulating SCs neuron responses to various visual stimuli and how it plays a role in the context-dependent modulation of size preference in approach behavior. Though these proposed studies, we hope to greatly enhance our understanding of functional organization, signal integration, intracollicular/interlaminar interactions as well as functional modulation in SC circuits.

NIH Research Projects · FY 2025 · 2007-08

Project Summary This renewal application will focus on the striatum. It stems from our recent study of the functional contributions of major corticofugal projections from the auditory cortex (ACx). Anatomically receiving convergent cortical and thalamic inputs, the striatum is believed to play an important role in central auditory processing and perception of sound, as evidenced by its involvement in sound-frequency discrimination related behaviors. However, fundamental questions about how specific auditory information is processed, integrated in the striatum, and transformed into appropriate actions remain not well understood. Since the caudal striatum, or the tail of the striatum (TS), receives the highest intensity of ACx projections among all striatal areas, our initial efforts will be centered on the TS, regarded as the “auditory striatum”, to explore its functional role in auditory processing and related behaviors. This proposal builds upon our recent studies on corticostriatal projections from ACx to TS in processing looming sounds, as well as on the mouse cortico-striatal-thalamic network. More importantly, our pilot results suggest that a midbrain structure adjacent to the MGB, known as the nucleus of the brachium of the inferior colliculus (NB in Allen mouse brain atlas, also named “NBIC” or “BIN” in the literature), provides significant bottom-up auditory signals to TS and influences its auditory processing. By exploiting mouse genetic models and combining a suite of cutting-edge approaches such as cell-type- and pathway-specific viral tracing, our recently established AAV1-based anterograde transsynaptic tagging, in vivo and ex vivo electrophysiology, miniscope calcium imaging, as well as optogenetic manipulations, we will test our central hypothesis that TS contributes to auditory spatial processing by integrating binaural information relayed from a unique ascending midbrain-striatal pathway. The proposed project aims to generate new insights into the functional role of striatum in auditory processing perception. Results from this project may help to advance our understanding of the pathophysiology of auditory processing disorders as well as striatum-related neuropsychiatric disorders.

NIH Research Projects · FY 2026 · 2007-05

Building resources to make data from high value, publicly funded cohort studies widely accessible, (re)usable, and interoperable is one of the National Institute on Aging’s key milestones of the Alzheimer’s Disease and Related Dementia (AD/ADRD) research implementation. The Gateway to Global Aging Data is a data platform developed to harmonize and disseminate data from the Health and Retirement Study and its international network of studies (HRS-INS) to facilitate longitudinal analyses on aging across 47 countries. Expanding on an already successful platform, this application aims to bring in newly available data on late-life cognition and dementia, collected using the Harmonized Cognitive Assessment Protocol (HCAP), together with other newly available data from core longitudinal interviews, self-completion questionnaire, Life-History interviews, and End-of-Life interviews to promote high-quality studies of late-life cognition, mild cognitive impairment (MCI), and AD/ADRD. We will also integrate contextual data, specifically, air pollution exposures, as well as institutional and policy measures related to long-term care and end-of-life care. Air pollution is a modifiable risk factor for AD/ADRD yet most research is from individual countries and focused on total particulate pollution. By newly estimating air pollution from different sources at respondent addresses, we will enable interested researchers to investigate the effects of exposures on cognitive decline, MCI, and AD/ADRD, across multiple countries. Similarly, the utilization, cost, and quality of long-term care related to dementia are emerging areas of concern. Thus, we aim to identify institutional and policy differences in formal long-term, informal, end-of-life, and dementia care for the respondents of the HRS-INS. As we grow our database with new measures and expand our user base, we seek to redesign the technical implementation of our metadata extraction, contextual data integration, and data management and dissemination application. Such investment in data infrastructure is justified when the data are widely used to produce novel and meaningful new knowledge, insights on population health, including AD/ADRD and dementia care, and ultimately policy innovations. To facilitate the widespread use of the Gateway’s resources, we will further strengthen user training and support by regularly organizing user conferences and workshops in addition to our regularly scheduled webinars. By amassing this expansive platform of high-quality information from the HRS-INS harmonized by subject-area experts, making these data publicly available, and conducting outreach to support use of these data, we anticipate that the Gateway will lead to impactful discoveries on the risks, care, and costs of AD/ADRD globally.

NIH Research Projects · FY 2025 · 2004-09

Abstract The vision of the USC-Yale Roybal Center for Behavioral Interventions in Aging is to expand the reach of effective behavioral interventions that address the over- and underuse of medical care through an understanding of their mechanisms of behavior change. The specific aims of the Center are to: (1) improve the general effectiveness of behavioral interventions that address over- and underuse of health services in aging populations by clarifying their mechanisms; (2) address crucial problems relating to translation and development of physician and patient interventions that facilitate value-based health care decisions, and (3) test up to 10 randomized trials that evaluate mechanisms of behavior change. Our Center will operate under the NIH Stage Model for behavioral interventions creating a pipeline of studies that span from basic research (Stage 0) through full-scale dissemination of interventions (Stage V). Work will be managed through an Administrative Core and research is conducted through a Behavioral Interventions Development Core. The Center has a diverse External Advisory Committee composed of experts in behavioral science, mechanisms of behavior change and health system leaders. Health system leaders work at implementation sites who will recommend the priorities for studying mechanisms of behavior change. Implementation site members are expected to broker relationships with their own institution so that these institutions can be test-bed for trials evaluated by the committee. We propose two randomized trials in the first year of the award. The first study aims to reduce potentially inappropriate prescribing in older adults who visit the emergency department. The second study aims to encourage older adults to designate a healthcare proxy. Both studies are Stage III and involve randomization. Pathways toward advancing the stages of these two projects are discussed as are solicitations for new trials in out-years. Continuity with the prior Roybal award is reflected in the Center’s focus on greatest potential for population health impact through improvements in medical decisions. Through its health system partners, the Center also expands its ability to support a growing community of researchers conducting behavioral interventions to encourage appropriate use of medical treatments for midlife and elderly populations.

NIH Research Projects · FY 2025 · 2004-02

This study aims to explore the molecular mechanisms, physiological functional significance, disease and therapeutic relevance of a radically new neuron-like function of the understudied but chief renal cell type of the macula densa (MD). MD cells are traditionally known as specialized renal epithelial cells capable of sensing the local tissue environment and releasing various chemical messengers to control renal and glomerular hemodynamics via tubuloglomerular feedback, and renin release as their classic functions. In addition, our work in the last grant cycle identified their novel function in endogenous kidney tissue remodeling and repair. However, interesting new insights suggest neuron-like function of these cells. Preliminary work using unbiased intravital multiphoton microscopy (MPM) of MD versus all other renal cell calcium responses uncovered neuron-like rapid and regularly oscillating spontaneous calcium transients (pacemaker activity), coordinated cell-to-cell propagation within the MD via long (>50 µm), axon-like cell processes that were entirely specific to MD cells. Numerous neurotransmitters and systemic neuroendocrine hormones given locally or iv triggered robust and specific MD cell calcium responses and increased afferent renal nerve activity. MD cell gene profile and tissue enrichment analysis identified brain tissue specificity of MD cells, and the expression of numerous neuronal markers including nerve growth factor receptor p75NTR (NGFR, the highest expressed growth factor receptor in MD cells), and some of the major Alzheimer’s disease risk genes. These studies painted a paradigm-shifting new picture of MD cells functioning as interoceptive neuron-like cells that form autonomous, nephron-level neuronal networks in the kidney, sense the local and systemic environment, process and send signals to renal and central effectors in the brain to maintain homeostasis. Our central hypothesis is that neuron-like MD cell calcium and NGFR signaling play novel primary roles in physiological responses to control renal hemodynamics, renin, and tissue remodeling (local interoception) and whole body homeostasis (systemic interoception). Further, we hypothesize that alterations in the neuron-like functions of MD cells represent a novel, neurodegenerative component in the pathogenesis of chronic kidney disease (CKD) and can be therapeutically targeted. This project will use comprehensive experimental approaches including new transgenic mice with chemo and optogenetic tools, in vivo MPM imaging including innovative 3-photon excitation, MD transcriptome analysis, bioinformatics, in vitro MD cell culturing and models of CKD. The specific aims are to examine the role of MD cell neuron-like calcium and NGFR signaling in (1) physiological responses of the JGA, (2) in the development and progression of kidney disease, and (3) their therapeutic potential in CKD. These novel MD cell-specific molecular and signaling mechanisms may be targeted in the future development of new first-in-class MD cell stimulating therapeutic approaches for CKD.

NIH Research Projects · FY 2026 · 2003-06

Organisms living on Earth cope daily with changes in their environment. An endogenous oscillator, known as the circadian clock, enables organisms to coordinate metabolism, physiology, and development in anticipation of diurnal and seasonal environmental changes and therefore, enhances fitness. The molecular network underlying the circadian system relies on interlocked transcriptional-translational feedback loops, in addition to multiple layers of regulation at the cellular and organismal level. We propose to deploy a combination of genetic, molecular, biochemical, physiological, bioinformatic, and genome-wide approaches to identify new components of the clockwork, and unravel the intricate wiring of the circadian clock in Arabidopsis. TOC1 is a key element of the core-clock of Arabidopsis. Recent data from our laboratory have shown that TOC1 binds to RNA in vitro. We propose to validate this biochemical property in vivo and study its biological relevance. We will also characterize TOC1 association with the transcriptional machinery and with hub components of hormone signaling pathways, which will be instrumental to understand the role of TOC1 in the circadian system. We further seek to explore the GI molecular network and propose to combine molecular, genetic, and biochemical analyses to study novel partners including transcription factors associated with pathogen responses, hormone and growth signaling. Preliminary data from our laboratory also suggest a potential role of the circadian clock in nitrate uptake. We aim to characterize nitrate uptake dynamics and by utilizing genetic, biochemical, and physiological studies we seek to identify the molecular mechanisms underlying the potential regulation of root physiology by the endogenous clock. By integrating different approaches including bioinformatic, classic plant photobiology tools and mutant screens, we propose to elucidate three distinct layers of the clock: to uncover the signaling pathway of light input to the clockwork; to identify new core-clock elements; and to discover components that are necessary for the oscillator to achieve different developmental or physiological traits. Mechanistic details from our study can be extrapolated outside the circadian field to advance research of other complex regulatory systems and ultimately impact work in human health, disease, and food security. D RELEVANCE (See instructions): This proposal will improve our insights of plant physiology and will provide a comprehensive understanding of the circadian system and the cellular processes associated with it. The study will ultimately impact research in human biological rhythms and treatment of circadian-linked health disorders.

NIH Research Projects · FY 2025 · 2002-06

Project Summary Metabolic dysfunction associated steatotic liver disease (MASLD), previously referred to as nonalcoholic fatty liver disease, or NAFLD, affects over 30% of the US population and is a leading cause of cirrhosis, liver cancer, and need for liver transplantation. The Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN), established in 2002, has focused on characterizing the natural history of the different phenotypes of MASLD, evaluating novel therapies to treat the condition, and conducting translational studies using a rich repository of clinical, pathologic, imaging, and -omics data to advance knowledge. Since the last funding cycle, the NASH CRN adult or pediatric clinical centers have enrolled 1575 participants into a longitudinal database, including 617 newly enrolled individuals and undertaken two clinical trials: the Losartan for Pediatric NAFLD (STOP-NAFLD) trial which was terminated early based on DSMB recommendation and the Vitamin E Dose Ranging Study (VEDS), initiated in 2021, which is 50% enrolled. During the current funding period, 219,404 total samples (serum, plasma, liver tissue, DNA and cDNA), including samples for ~1,220 new patients, were added in the NIDDK Biorepository, and 49,957 samples withdrawn for translational research using the Ancillary Studies mechanism. The objectives of the NASH CRN during the final funding period are (a) to successfully complete the observational longitudinal study of NAFLD in adults and children (NAFLD Database study, (b) complete the enrollment and follow-up of the VEDS clinical trial (N=250) and to conduct new translational studies based on the clinical and archived biospecimens from previous funding These studies may focus on (but not limited to) natural history of NAFLD and NASH in children and adults, non-invasive assessment of disease severity (e.g., proteomics, lipodimics, clinical prediction rules) and disease pathogenesis (cytokine analyses, genome-wide association studies, tissue proteomics). Site-specific studies include measurement of individual- and neighborhood-level social and structural determinants of health (SSDOH) including geospatial variables, to determine their influence on MAFLD development and progression and to evaluate whether the social and structural environment, as measured by the social deprivation index, modifies the risk of germline genetic variants (PNPLA3 and others) on disease severity and progression. Collectively, these studies are and anticipated to address key knowledge gaps in MASLD diagnosis, treatment and prognosis.

NIH Research Projects · FY 2026 · 2002-05

Summary (30 lines) The long-term objective of our research is to understand the basic principles regulating the development and regeneration of skin and its appendages, and to apply this knowledge to regenerative medicine. Recent progress in stem cell biology has allowed the production of skin substitutes which help patients suffering from severe skin injuries to survive. Yet, these skin substitutes lack regional specificities seen in human skin (e.g., scalp, face, palm, sole). The next major challenge will be to produce skins with proper region-specific phenotypes for optimal function. While studies on region-specific skin in the mouse ear, sole and human fibroblasts were carried out, no systemic studies have been made. Birds exhibit remarkable region-specific skin appendages for communication, endothermy and flight, and are accessible to experimentation. We have demonstrated how temporo-spatial expression of diffusible morphogens (Wnt, FGF, BMP and their antagonists) can mediate epidermal-dermal interactions to generate distinct skin appendage phenotypes. Yet, how these morphogens work at the epigenetic level, including upstream in the dermis and downstream in the epidermis, are mostly unknown. Several recent studies provide new clues. First, the scalp is known to be a unique skin domain with distinct appendage phenotypes in humans (terminal hairs or alopecia) and birds (crest feathers or combs). Polish chicken variants grow feathers instead of the comb on the scalp. Using genetic analyses, we showed a195 bp duplication in the non-coding region of HoxC10. This study offers new clues to study how misexpression of HoxC members can act on morphogens to change combs into feathers, and how the HoxC gene cluster is regulated. Second, using transcriptome analyses to compare dorsal and shank skin, we recently identified a group of molecular scale-feather converters. Following this clue, we performed ATAC- seq and high-order chromatin interactome studies to explore 3D genome organizations in feathers, scales, and intermediate specimens. Preliminary data reveal differential chromatin accessible regions in feather / scale inductive dermis, and in competent / committed epidermis, providing new insights into the induction of region- specific skin appendages. Thus, the time is ripe to follow these clues to advance our understanding of skin regional specification. We hypothesize that dermis in different skin regions exhibit distinct epigenetic profiles, leading to specific combinatorial morphogen expressions, which guide epidermis to form specific appendage types. In development, epidermal cells, during a time window, can exhibit bipotent competency to respond to different dermal signals and form specific appendage types. The hypothesis will be evaluated and developed further using a combination of classical tissue transplantation experiments and cutting-edge omics technologies. We will focus on the scalp, dorsal and shank skins in this study but consider the fundamental principles that would be applicable to other skin regions. The work will advance our understanding of how region-specific skin appendages are established from the morphogen level to the epigenetic level.

NIH Research Projects · FY 2025 · 2001-06

Abstract The Integrative Liver Cell Core (ILCC) strives to serve the scientific community of alcoholic liver disease (ALD) and cirrhosis via specialized services of isolating 6 different liver cell types (hepatocytes, HC; hepatic macrophages, HM; hepatic stellate cells, HSC; sinusoidal endothelial cells, SEC; mesothelial cells, MC; and CD133+ ductular reaction progenitors, DRP) from 12 different ALD and liver fibrosis models which reproduce wide and specific spectra of liver diseases. To support leading-edge cell type specific research, the ILCC also couples these isolation procedures with innovative techniques: 1) Rosa26-reporter mouse-based genetic lineage and cell fate tracing for HC, DRP, HSC, and HM in ALD and alcohol-promoter liver tumor; 2) fluorescence- activated cell sorting (FACS)-based analysis of resident vs. migrating HM to assess their relative contributions to alcoholic steatohepatitis; 3) FACS-based isolation of vitamin A+/Col1a1- quiescent HSC, vitamin A+/Col1a1+ activated HSC, and vitamin A-/Col1a1+ mesenchymal cells from mouse ALD models; and 5) FACS isolation of CD133+ tumor-initiating stem cell-like cells and DRP from alcohol-promoted liver tumor and alcoholic hepatitis. To achieve these integrative services, the ILCC closely collaborates with the Animal Core of the P50 Alcohol Center and supports genetic loss or gain of function approaches at each specific cellular level in mouse models of chronic alcoholic steatohepatitis, alcoholic hepatitis, alcoholic liver fibrosis, and alcohol-promoted liver tumor. Since the last renewal submission, the ILCC served 41 investigators from 25 institutions by performing 1,151 isolation preparations and providing 283 Cell Bank samples. These efforts facilitated 34 publications and acquisition or continuation of 20 federal grants plus 2 pending applications. Of these 41 investigators, 22 were out-of-region investigators and 14 were early career investigators across the country, attesting that the ILCC contributes as a national resource. The proposed ILCC renewal aims to continue its unique and cutting-edge services of liver cell isolation and analysis and to promote genetic, epigenetic, metabolic, and molecular research on altered cell fate regulation of different liver cell types which manifest as fundamental mechanisms underlying inflammation, fibrosis, and tumorigenesis in ALD.

NIH Research Projects · FY 2025 · 1999-08

The USC/UCLA Center on Biodemography and Population Health (CBPH) represents a unique and highly successful collaboration between the Leonard Davis School of Gerontology of the University of Southern California (USC) and the Multi-campus Program in Geriatric Medicine and Gerontology in the Geffen School of Medicine at the University of California at Los Angeles (UCLA), each of which focuses exclusively on research and teaching on aging. The CBPH has a longstanding role as a leader in efforts to promote theory-based integration of biological measurement into population-based studies, on-going development and validation of biological measurement protocols, and theoretically motivated research on the biological mechanisms by which social, economic, psychological, medical and environmental factors “get under the skin” to influence the process of health change with age. The CBPH has developed unique clinical and laboratory infrastructure and pilot projects to improve understanding and use of biodemographic indicators, increase indicators available to population studies, support more reliable and valid collection of data across a large number of national and international surveys, and made advances in measurement and validation that allow population surveys to keep pace with scientific advances in the science of aging. This application proposes a set of activities designed to (i) expand and enhance theoretical development of the field of biodemography so that we focus on a new generation of biomarkers reflecting molecular and cellular processes that reflect the basic mechanisms of aging, (ii) continue efforts to attract new and promising researchers to the field, and (iii) enhance our Center’s unique role in supporting development, validation, implementation and dissemination of new and better biodemographic measurement protocols. The specific aims of the CBPH will be to: (1) support and foster biodemographic research to understand the multiple and interacting factors that affect population health, with a particular focus on expanding and deepening our understanding of the biological pathways through which experiences and exposures over the life-course impact trajectories of health and how such influences may vary across subgroups and settings); (2) further develop an active biodemographic research community by engaging established and promising junior researchers in a network of scholars who can help advance biodemographic research; (3) fund pilot projects to support cutting-edge biodemographic research; and (4) support development and dissemination of new research technologies, methodologies and data for use in biodemographic research and population surveys. Such advances are needed to support development of models of population health that provide much needed evidence for policy planners regarding the most effective points of intervention to improve population health and reduce health disparities. The CBPH has developed the infrastructure, resources and expertise to accomplish its goals and continue its significant leadership role in advancing biodemographic research on aging.

NIH Research Projects · FY 2026 · 1999-01

Project Summary Realizing the full potential of otoacoustic emissions (OAEs) as noninvasive probes of cochlear function requires understanding the physical and physiological mechanisms that generate and shape these sounds. To address important unresolved issues of cochlear mechanics while improving our understanding of OAE generation, we propose three aims involving innovative theoretical modeling rigorously tested by experimental measurements. The first Aim seeks to understand how the active, nonlinear cochlea analyzes frequency sweeps, an ecologically important and readily manipulable class of dynamic sounds. Through an innovative mix of behavior, physiology, and theoretical modeling we will test our hypothesis that up-down differences in behavioral masking, cochlear suppression, and the generation of reflection-source OAEs all share a similar, non-monotonic dependence on sweep rate and direction, consistent with the involvement of temporal suppression. As an important control, we will evaluate possible contributions from feedback-based auditory reflexes. We will interpret our results using models of cochlear wave amplification and OAE generation to test the hypothesis that the measured response patterns arise via mechanisms involving interactions between traveling-wave dispersion and nonlinear suppression. The second Aim explores the micromechanics of cochlear wave amplification and its consequences for the generation of distortion-product OAEs (DPOAEs). We study DPOAE generation in tightly controlled models that incorporate a variable mix of both local (classical) and nonlocal (push-pull) amplification, the latter as suggested by the prevailing interpretation of the oblique geometry of the outer hair cells within the organ of Corti. The project will determine how the known properties of DPOAEs constrain the nature of the active forces responsible for boosting the sensitivity of hearing. The third Aim studies contributions to cochlear gain arising not directly via active forces within the organ of Corti but via hydrodynamic effects (“pressure focusing”) that depend on fluid coupling within the geometry of the cochlear duct. Our methods allow us to vary the hydrodynamic coupling independent of cochlear micromechanics, enabling us to evaluate the robustness of a promising new method for understanding the functional role of the many details of cytoarchitecture. Completion of these Aims will significantly enhance our understanding of OAE generation and its relationship to cochlear amplification and nonlinearity. The knowledge we gain is also directly relevant to our long-term goal of improving the power of OAE-based diagnostics and other technological applications—such as hearing aids and preprocessors for speech-recognition devices—that benefit from the knowledge of cochlear amplification, nonlinearity, and signal processing.

NIH Research Projects · FY 2026 · 1998-12

OVERALL - SUMMARY Alcohol-associated liver and pancreatic diseases (ALPD) and cirrhosis constitute leading metabolic diseases caused by alcohol use disorder around the globe. The Southern California Research Center for ALPD and Cirrhosis unifies 60 investigators from six academic institutions in Southern California to pursue a common mission of being a leader in research, training, outreach, and treatment for the diseases. The center, since its inception in 1999, has devoted its efforts for development and use of clinically relevant animal models to gain novel insights into the molecular mechanisms of ALPD and cirrhosis. These efforts culminated to groundbreaking discoveries and new therapeutic developments for the diseases such as a phage cocktail to treat alcohol-associated hepatitis patients with cytolysin-positive E. faecalis, anti-IL-23 monoclonal antibody for patients with alcohol-associated liver disease, and Simvastatin for treatment of recurrent acute pancreatitis. The center’s interactive infrastructure and environment have facilitated in the past 5 years: a 134% increase in research base to $21.6M/year; 11 new U01/P01/MPI-R01 programs and 3 DOD program projects; 241 publications; 8 NIH/DOD-funded early-stage investigators; 14 postdocs transitioned to faculty positions at US universities; 99 graduate students taught and 44 students undergone the Lee Summer Research Fellowship; and 4 workshop/community seminars and 4 international symposia organized. As a unique national resource, the center has supported 15 non-center investigators via provision of 383 model mice and 333 biospecimens by the Animal Core, facilitating their 13 grant acquisitions and applications. We further consolidated the regional repository resources to advance our ALPD translational and clinical studies in pursuit for novel therapeutic modalities. The center will continue to strive as a unique national scientific center of excellence in ALPD and cirrhosis by: 1) maximizing our interactive and synergistic science for a pursuit for the center’s main goal of identification of therapeutic targets for advanced ALPD and cirrhosis; 2) serving as a national and international resource in our fields of research via provision of unique models, technology, expertise, and collaborative opportunities with outside NIAAA-funded scientists; 3) providing comprehensive education and training at the multi-levels ranging from undergraduate and graduate students, postdoctoral trainees, to junior scientists and faculty to foster and support future generations of independent scientists in the ALPD and cirrhosis field; and 4) continuing outreach efforts to disseminate the center’s new findings to lay public, healthcare workers, and scientists in our home and global communities.

NIH Research Projects · FY 2026 · 1998-03

Abstract Cyclic GMP and calcium (Ca2+) are effectors of phototransduction and maintenance of their homeostasis is critical for photoreceptor cell health and function. Indeed, perturbance of this homeostasis is thought to be a primary driver of cell death in different forms of retinal degenerations. For example, mutations affecting phototransduction genes leading to elevated cGMP is expected to cause toxic Ca2+ influx into the outer segment via the cGMP-gated channels. Although a reasonable hypothesis, it is difficult to reconcile with 1) the cell death machinery is localized in the inner segment, and 2) the current dogma that the outer and inner segments Ca2+ are compartmentalized and insulated from each other. This raises an important and unanswered question: how does [Ca2+] buildup in the outer segment alter [Ca2+] in the inner segment to activate cell death? Our central hypothesis is that altered Ca2+ homeostasis at the outer segment leads to mitochondrial stress at the inner segment. This, in turn, allows Ca2+ to equilibrate with the proximal cell compartments where the cell death machinery resides. To test this hypothesis, we will use mouse models that express genetically encoded, ratiometric Ca2+ indicators in retinal rods and cones. To prevent activating the photoreceptor cells, we will use 1) a multiphoton microscope equipped with a super-sensitive HyD detector that images under extremely low photon flux and 2) mouse models with attenuated phototransduction to reduce Ca2+ feedback. Using retinae obtained from both male and female mice, we will image [Ca2+]i from different cellular compartments simultaneously, in both dark adapted and light exposed conditions, in healthy and degenerating photoreceptors, to visualize how changes in [Ca2+] in one cellular compartment may affect [Ca2+] in another compartment. The proposed experiments should provide a better understanding of the role of Ca2+ homeostasis in health and disease.

NIH Research Projects · FY 2025 · 1997-06

OVERALL: PROJECT SUMMARY/ABSTRACT The mission of the Southern California Environmental Health Sciences Center (SCEHSC) is to develop the scientific knowledge base, investigator teams, and community engagement needed to reduce the burden of diseases and disability from environmental impacts. The SCEHSC explores the effects of environmental exposures across the lifecourse with an emphasis on susceptible populations, critical developmental periods, and major diseases which are mediated through shared molecular and biological pathways. The SCEHSC’s theme is Environmental Exposures, Host Factors and Human Disease across the Lifecourse. Scientifically, the SCEHSC is organized around six Environmental Health Research Programs: two Methods Research Programs (Exposure Sciences; Biostatistics & Data Science) and four Health Outcomes Research Programs (Cardiorespiratory; Neurological; Obesity & Metabolic; Cancer). The Research Programs are led by collaborative multidisciplinary teams and supported by the SCEHSC’s Administrative and three Facility Cores. The Community Engagement Core promotes multidirectional science communication with community partners and the public. The SCEHSC fosters innovative research in environmental health sciences (EHS) using the Pilot Projects Program, state-of-the-art Facility Cores, and collaborative mechanisms including seminar series, workshops and symposia, working groups, retreats, and career development activities. Over the past 24 years, the SCEHSC has functioned as an integrated program of research excellence. We have a strong research base in EHS as demonstrated by ongoing peer-reviewed research projects. Our EHS identity has been further distinguished by our success in bringing together multidisciplinary research teams tackling compelling and complex issues in EHS, attracting new and accomplished investigators to EHS, and fostering new lines of research. The SCEHSC is a national leader in community engagement, improving environmental health literacy and employing innovative approaches for community involvement and multi-directionally communicating EHS research results. This engagement with community organizations, policymakers, the public health community, social and traditional media, and the general public has a proven track record of fostering solutions-oriented and sustainable policy. In the renewal period, we propose to build on these approaches to promote cutting-edge science, translational research, and community engagement, and to develop the next generation of EHS leaders. The SCEHSC’s mission, theme, structure, goals, strategic approaches, and future directions will contribute to advancing many elements of the NIEHS Strategic Plan. The broad spectrum of expertise among our diverse membership’s strong track record in collaborative multidisciplinary research, career development, and solutions-oriented community engagement position the SCEHSC to effectively address today’s critical problems and tomorrow’s emerging EHS challenges.

NIH Research Projects · FY 2026 · 1996-12

PROJECT SUMMARY – Overall Component The USC Norris Comprehensive Cancer Center at the University of Southern California (NCCC) has been continuously funded as an NCI-designated Comprehensive Cancer Center since 1973. NCCC has a rich tradition of collaborative research and serves as a major regional and international resource for cancer research, education, community outreach and engagement, and patient-centered oncology care. Our vision is to reduce the burden of cancer for all people. A central priority for NCCC is to serve the unique cancer-related needs of our multicultural catchment area, Los Angeles County (LAC). To achieve this goal, our 187 full members form collaborative teams and are organized into five impactful Research Programs served by six valuable Shared Resources (SRs). NCCC’s Cancer Research Training and Education Coordination (CRTEC) programs are part of the fabric of these efforts, creating a robust pipeline for the next generation of exceptional cancer scientists and clinicians. The NCCC Office of Community Outreach and Engagement (COE) is the primary vehicle by which we understand, engage, and serve the needs of the communities in our catchment area. Our geographic location in the nation’s second largest city affords opportunities for NCCC to lead in research that addresses cancer burdens among many communities and special populations. Indeed, NCCC is distinguished by exceptional success in recruiting these communities to clinical trials. This application requests: 1) support for five interactive Research Programs; 2) partial support for six SRs and one Developing Preclinical SR that provide technologies, services, and scientific consultation that will enhance member interaction and productivity; 3) support for Leadership, Planning, and Evaluation; 4) support for Developmental Funds to foster pursuit of new priorities, strengthen science, and explore new collaborations and technologies, all aligned with the new NCCC Strategic Plan; 5) support for Cancer Center Administration; and 6) support centralized scientific oversight of cancer clinical trials. Members currently hold grants totaling $101.3M (direct costs) with $37.7M from NCI and have authored landmark publications representing high intra-programmatic (26%), inter-programmatic (25%) and multi-institutional (45%) cancer research. Continued funding from the Cancer Center Support Grant (CCSG) will allow us to build on our strengths in basic, population, and clinical sciences, and to facilitate discovery and its translation into direct benefit to patients and our catchment area communities.

NIH Research Projects · FY 2025 · 1996-07

The lacrimal gland (LG) produces fluid and proteins essential for ocular surface function. A subset of severe dry eye disease (DED) cases are associated with Sjögren’s syndrome (SS), an autoimmune disease associated with exocrinopathy and systemic inflammation. SS-associated DED is characterized by severe LG inflammation (dacryoadenitis) and reduced tear secretion, with tears containing an altered spectrum of proteins which may provoke ocular surface inflammation. In the male NOD mouse, a model of ocular symptoms of SS, expression and activity of cathepsin S (CTSS) is highly increased in LG and in tears in parallel with disease; increased tear CTSS is also seen in SS patients. Treatment of male NOD mice with a CTSS inhibitor suppressed ocular symptoms of SS. A complication of the use of CTSS inhibitors reported so far in clinical trials is the induction of additional CTSS expression, suggesting a feedback loop responsible for the regulation of the expression and activity of this enzyme which is so critical in inflammatory processes. An alternative to CTSS inhibition for treatment of ocular symptoms of SS is identification and reversal of processes in the LG driving its: 1)increased expression; 2) increased tear secretion; and 3)participation in LG inflammation. Three Aims are proposed: Aim 1. Does dysregulation of PP2A signaling contribute to increased CTSS in LGAC in SS? Protein phosphatase 2A (PP2A) regulates CTSS mRNA stability/translation through dephosphorylation of tristetraprolin (TTP). Mechanisms of dysregulation of PP2A-TTP leading to increased CTSS expression and secretion from LGAC will be explored in NOD and control mice, and in cultured LG acinar cells (LGAC). The efficacy of the PP2A activator, DT-061, on LG and ocular surface disease will be determined in NOD and control mice. Aim 2. Does increased trafficking through the minor secretory pathway promote increased tear CTSS in SS? Most tear proteins are secreted from the LGAC “major” secretory pathway, but a “minor” pathway from endolysosomes may contribute CTSS to tears. In Rab deficient mice with altered tear contributions from major and minor pathways, changes in minor pathway cargo in tears beyond CTSS will be identified. Correlative light and electron microscopy will identify endolysosomal membranes responsible for minor pathway secretion; these new measures will be applied to test whether the minor pathway is increased in SS using NOD and control mice. Aim 3. Does local or systemic modulation of endolysosomal traffic through PIKFYVE inhibition suppress CTSS-mediated pathology in SS? PIKFYVE is a master regulator of endolysosomal trafficking and maturation, regulating CTSS function in antigen presentation and expression of IL12/23. The effects of local and systemic inhibition of PIKFYVE on ocular symptoms of SS will be evaluated in NOD and control mice, in parallel with additional indicators of LGAC autoimmune epithelitis, tear and exosome abundance, and expression of IL-12/23. Results from these studies will collectively define changes in secretory pathways that may contribute to ocular manifestations of SS, while identifying new therapeutic agents yet unexplored in SS to mitigate ocular disease.

NIH Research Projects · FY 2025 · 1993-07

PROJECT SUMMARY: Thalamic circuits are dominated by two sources of inhibition that have a profound influence on the type and quantity of information that relay cells transmit from eye to brain: These are local interneurons within the dorsal lateral geniculate nucleus of the thalamus (dLGN), and the visual sector of the thalamic reticular nucleus (TRN)— a thin sheet of GABAergic cells that lies nearby. Local interneurons receive retinal input and synapse with relay cells and each other to supply powerful feedforward inhibition. By contrast, relay cells make only sparse connections within the main layers of dLGN. Rather, they contact neurons in TRN, whose dense axonal arbors provide feedback inhibition in return. In addition to receiving ascending information, these three types of cells (local interneurons, relay cells, reticular cells) in the dLGN/TRN complex are embedded in a larger network that involves top-down input from cortex; this arrangement is repeated across primary thalamic nuclei in mammals. Thus, learning how thalamic circuits operate is key to understanding sensory integration and, moreover, serves studies of disorders such as amblyopia or the development of visual prosthetics by providing a blueprint for how healthy brains function. Here we focus on TRN in mouse, a species that has become central to studies of vision because of the many experimental advantages it offers, but whose visual system differs somewhat from those of traditional experimental subjects like carnivore and primate. The design of the project is inspired by a framework voiced by Francis Crick, who theorized that TRN might act as a searchlight that increases thalamic activity in specific regions of interest, or as a thermostat that regulates levels of global activity. We evaluate predictions of each hypothesis to explore visual processing per se, by combining comparative, optogenetic, physiological, anatomical, and computational approaches. The project comprises three interrelated aims, as follows. The searchlight hypothesis suggests that receptive fields in TRN are feature specific and localized and we have shown that this is the case in carnivore; Aim 1 uses physiological and computational approaches to analyze the spatiotemporal features encoded in mouse visual TRN across visual space. These results are then incorporated into a model framework that ties the output of inhibitory cells, including TRN and local interneurons (we have studied these previously) to patterns of inhibition recorded from the relay cell’s receptive field. Aim 2 explores the link between receptive field structures in dLGN and TRN mechanistically by exploring how input from dLGN influences visual response properties in TRN and vice versa; opsins that suppress synaptic transmission and statistical tools that reveal connectivity between neurons are used to approach this topic. Finally, Aim 3 takes the general perspective of the thermostat hypothesis and asks how responses of TRN to global stimulus properties might regulate, at one extreme, inhibitory tone in dLGN, and, at the other, the fine temporal structure of the relay cell’s response. Taken together, our results will provide critical insight into thalamic contributions to visual processing that are conserved across species.