Weill Medical Coll Of Cornell Univ

NIH Research Projects · FY 2026 · 2026-03

PROJECT SUMMARY The proposed project encompasses a comprehensive research plan to support the development of my career as an independent scientist focused on investigating the assembly and conformational dynamics of neuronal integral membrane receptors, and how structure is related to receptor activation and regulation. This biophysical mechanism-focused approach to receptor function will guide promising therapeutic development. Background: The neurotrophic receptor tropomyosin kinase receptor B (TrkB) is a member of the receptor tyrosine kinase (RTK) superfamily of integral membrane proteins which receive extracellular signals and initiate intracellular signaling cascades across the cellular membrane. Canonical RTK activation is characterized by a transition from a monomeric receptor to a dimeric receptor following ligand binding. However, receptor assembly studies on EGFR, an extensively studied RTK, demonstrate that this activation pathway is much more complex than initially thought as an ensemble of ligand-dependent conformations have been observed. Despite the role that TrkB plays in neurodegenerative, psychiatric, and oncological disease, no effective therapeutic agent that targets TrkB is available due in part to the overwhelming lack of structural information relating to receptor function. Specifically, the field currently lacks an understanding of TrkB dimeric assembly and how this relates to intersubunit and intrasubunit conformational dynamics across domains. Specific Aims and Research Design: The proposed study investigates TrkB assembly, structure, and conformational dyanmics using 1) single-molecule and ensemble fluorescence-based binding methods to investigate the molecular determinants of TrkB dimerization 2) cryogenic electron microscopy (cryoEM) to assess the structural basis of TrkB dimeric assembly and allosteric activation. My in vitro and structural findings will be validated and extended by cellular and functional assays. Together this work will guide the development of a K99/R00 proposal aimed to apply the approaches and findings from this F32 research program broadly to other neuronal integral membrane receptors and to pursue the functional consequences of TrkB receptor assembly and conformational shifts in in vivo models. Training and Mentoring: My training goals are supported by 1) my sponsor Dr. Levitz and my assembled team of carefully selected consultants and collaborators with a range of expertise in membrane protein biophysical and biochemical research, 2) a flourishing institutional environment at Weill Cornell Medical College, and 3) scientific meetings, seminars, and planned publications. Impact: The invaluable experience gained during this award will serve as the foundation for my independent career as a protein biophysics researcher and for the development of a novel program of membrane protein research.

NIH Research Projects · FY 2025 · 2026-03

PROJECT SUMMARY/ABSTRACT Insulin resistance is a blunted signaling response that is associated with the development of many diseases, including, type 2 diabetes (T2D), obesity, and metabolic dysfunction-associated fatty liver disease (MAFLD). Insulin resistance and its associated diseases are some of the leading causes of morbidity and death worldwide. Despite extensive knowledge of the drivers and stressors that contribute to insulin resistance, there is a relative lack of consensus for a molecular, mechanistic model that explain how insulin resistance occurs. Recent reports indicate that signaling factors can form dynamic biomolecular condensates, which are mesoscale cellular compartments that concentrate biomolecules and have liquid-like properties. A condensate model provides a new framework to explain how changes in the physico-mechanical features of condensates promote the development of insulin resistance. I discovered that the insulin receptor (IR) forms dynamic, liquid-like condensates that have insulin-dependent functional activity. In insulin resistance, IR condensates become dysfunctional. IR condensate dysfunction is in part due to increased levels of reactive oxygen species (ROS). Furthermore, I found that IR condensate dysfunction is also seen in patients with type 2 diabetes. However, it remains unclear how IR condensates form in heathy cells and become dysfunctional in insulin resistance. I hypothesize that in insulin sensitive cells domains of IR promote condensate formation, which when oxidized in insulin resistance drive IR condensate dysfunction. To address this, I will 1) dissect the molecular requirements for IR condensate formation and 2) determine the molecular changes that promote dysfunctional IR condensates. These aims will advance our understanding of how dysregulated IR condensates promote insulin resistance and will lead to new innovations in the treatment and prevention of insulin resistance and its associated diseases, including type 2 diabetes, obesity, and metabolic dysfunction-associated fatty liver disease. As the PI of this project, I, Dr. Jesse Platt MD PhD, am a physician-scientist performing mentored research in the lab of Dr. Richard Young. My long-term career goal is to develop an independent, academic research laboratory that investigates the role of biomolecular condensates in gastrointestinal health and disease and leverages this knowledge for therapeutic benefit. I will spend 80% of my time engaged in the proposed research, and 20% of my time caring for patients with liver disease. Dr. Young is an expert in biomolecular condensates. I will be guided by an exceptional committee of mentors, including: Dr. Phillip Sharp, Dr. Linda Griffith, and Dr. Rudolf Jaenisch. I will obtain training in biochemistry, microscopy, and mass spectrometry while developing skills in grant writing and leadership. With an outstanding institutional environment, training plan, career development plan, mentorship, and proposed research, this K08 award will enable me to conduct groundbreaking research and transition to independence.

NIH Research Projects · FY 2026 · 2026-02

Mouse models are critical for studying the pathogenesis of tuberculosis (TB) and for assessing new drug targets, treatment regimens and vaccine strategies. Standard C57BL/6 and BALB/c mouse models do not develop the pathology observed in humans, such as necrotic, hypoxic and caseating granulomas. In contrast C3HeB/FeJ mice develop a spectrum of TB lesions that more closely resemble human granulomas and other pathological environments. However, this mouse strain has rarely been utilized to investigate Mycobacterium tuberculosis (Mtb) mutants or paucibacillary Mtb infections that mimic latent infections in humans. We propose to analyze conditional knockdown mutants for thioredoxin reductase (TrxB2) and biotin protein ligase (BPL) in C3HeB/FeJ mice. We will determine the ability of conditional Mtb mutants to establish infection in mice with human-like pathological environments and determine the impact of TrxB2 and BPL depletion in different lesion types. We will establish genetic latency models in C3HeB/FeJ mice and test the hypothesis that a larger percentage of mice with caseous necrotic pulmonary granulomas will harbor latent bacilli that cause TB relapse than observed in C57BL/6 mice.

NIH Research Projects · FY 2026 · 2026-02

PROJECT SUMMARY/ABSTRACT This mixed-methods study aims to examine the effectiveness of Civil Monetary Penalties (CMPs) in enhancing care quality within nursing homes. The study focuses on determining whether CMPs serve as effective deterrents against substandard care or if they inadvertently exacerbate existing care deficiencies by imposing financial strains on facilities. Utilizing a comprehensive dataset encompassing nursing home resident claims data from 2011 to 2024, which includes detailed facility information and enforcement actions from the ASPEN/CASPER administrative data sets, this project will analyze the impacts of CMPs on nursing home care outcomes. Aim 1 of the project will explore the relationship between CMPs and the incidence of nursing home deficiencies, considering certain resident, facility, operational, and external factors that may influence the magnitude and frequency of CMPs. Aim 2 will employ a difference-in- differences analytical approach to assess the direct impacts of CMPs on quality of care by comparing outcomes before and after penalties are imposed in facilities relative to comparison facilities with no penalties over the same period. This aim will provide a clearer picture of the causal effects of CMPs on resident care quality. Aim 3 will involve conducting in-depth qualitative interviews with state surveyors and nursing home administrators to capture insights into the variability of CMP implementation and its perceived effectiveness across different states. This aim seeks to understand the on-the-ground challenges and operational perspectives regarding CMP enforcement. We will integrate findings across Aims using a concurrent-embedded approach. The comprehensive approach of this study is expected to yield valuable empirical evidence that will inform policymakers and help refine regulatory practices to ensure that CMPs are applied effectively and fairly. By assessing whether CMPs enhance care quality without unintended negative consequences, this research supports the broader goal of improving elder care across the United States.

NIH Research Projects · FY 2026 · 2026-02

Project Summary In 2022, over 10 million individuals were diagnosed with tuberculosis (TB) and 1.3 million died of the disease. Approximately 4% of these infections consisted of drug resistant TB (DR TB; defined as rifampin or multidrug resistance), which accounted for a disproportionate 12% of TB-related deaths. A major advancement in the treatment of DR TB came with the approval of bedaquiline, a new mycobacterial ATP synthase inhibitor that is the current backbone of second-line regimens. Addition of bedaquiline to second-line regimens has decreased mortality in patients with DR TB and reduced the length of treatment to 6 months. Newer bedaquiline-based combination therapies are now being investigated as potential short-course universal treatment regimens for TB. Rising rates of low-level resistance to bedaquiline threatens these recent gains. Strategies that boost bedaquiline's anti-TB activity may therefore have relevance for further shortening bedaquiline- based anti-TB regimens to less than 6 months and for combatting existing low-level resistance. Our preliminary data shows that the principal metabolite of aspirin, salicylate, enhances bedaquiline's anti-TB activity at a concentration readily achievable in humans. Salicylate may achieve this effect by shuttling the resulting buildup of protons (from bedaquiline's inhibition of ATP synthase) from the intermembrane space into the cytoplasm. This can kill Mycobacterium tuberculosis (Mtb), the causative agent of TB, by further depleting ATP levels and acidifying the Mtb cytoplasm. The aim of this proposal is to quantitate, validate, and better understand how salicylates potentiate bedaquiline's anti-TB activity. The first aim is to quantify this effect in order to identify salicylate and bedaquiline concentrations that result in best anti-TB activity. We will also explore whether other salicylate-based NSAIDs with stronger protonophoric activity show stronger or more potent potentiation of bedaquiline; and to what extent this potentiation restores bedaquiline's activity in clinical Mtb strains with low-level bedaquiline resistance. In the second aim, we will test the hypothesis that salicylates' aforementioned shuttling of protons is its mechanism of action for boosting of bedaquiline's activity. In the final aim, we will translate our findings by utilizing a macrophage infection model that better approximates the environment and stressors Mtb faces upon infection. These three aims will provide crucial preliminary data to justify progression of at least one of these salicylates into animal models, with the ultimate goal of human trials, with the aim of shortening existing bedaquiline-based regimens and addressing the most common form of resistance in the near term.

NIH Research Projects · FY 2025 · 2026-02

PROJECT ABSTRACT Millions of Americans suffer from inflammatory bowel disease (IBD), a condition marked by intestinal inflammation and abdominal pain. While the impact of the gut microbiota in IBD has been widely studied, the gut fungal “mycobiata” —and particularly the species of fungus Candida albicans— has emerged as a potential critical factor in this disease. While recent studies have revealed elevated levels of Candida albicans in IBD patients correlate with increased inflammation, the mechanisms underlying this connection remain unclear. Our research investigates how Candida albicans colonization contributes to intestinal inflammation and abdominal pain in a murine model of fungal dysbiosis. Preliminary data suggest that fungal colonization induces neutrophil infiltration , driving inflammation and tissue damage. We hypothesize that this inflammatory environment affects several disease aspects, directly via the fungal toxin candidalysin, or indirectly, through key proinflammatory cytokines . To address these hypotheses, I will use cell culture and murine models to examine how fungal colonization and candidalysin production drive inflammation, receptor activation, or influence abdominal pain. By exploring the direct and indirect effects of fungal virulence factors on neuroimmunity, this work will advance the understanding of fungal-immune-neuronal interactions in IBD and will hopefully advance the search for new potential therapeutic targets .

NIH Research Projects · FY 2025 · 2026-01

PROJECT SUMMARY/ABSTRACT Double-strand breaks (DSBs) are a highly toxic form of DNA damage. The accurate and preferred DSB repair pathway is homologous recombination (HR), which uses the sister chromatid as a repair template during S/G2 cell cycle stages. Alternatively, the error-prone nonhomologous end joining (NHEJ) ligates broken ends together primarily during G1. Recently, data in yeast suggest that RNA can be used as a template for DNA DSB repair through reverse transcriptase (RT) activity. While human cells have shown that RNA transcription promotes the recruitment of DNA repair proteins to DSBs, there is no evidence that RNA is directly templating repair. This has so far been difficult to study due to a lack of assays to measure this scarless repair pathway. Therefore, we developed a fluorescence-based BFP-to-GFP conversion reporter that measures repair of a DSB in the BFP gene via a single-stranded donor oligonucleotide coding for GFP. From this reporter, ribonucleotides within a DNA donor could template DSB repair in human cells, necessitating the use of a reverse transcriptase for this RNA-templated DSB repair (RT-DSBR). Through a CRISPR-Cas9 screen, we identified the involvement of Polymerase Zeta (PolZ). We validated the role of PolZ in RT-DSBR through the BFP-to-GFP assay as well as a sequencing-based assay using a pure RNA donor with an insertion signature. Therefore, the objective of my project is to unveil how PolZ and RNA work together to drive RT-DSBR in human cells. I hypothesize that mRNA can template DSB repair at highly transcribed regions and that PolZ is the reverse transcriptase that mediates this activity. The first part of my research will investigate the mechanistic basis of PolZ as an RT during RT- DSBR (Aim 1). I will identify the subunits of PolZ necessary for RT-DSBR activity via a pure RNA donor assay and use structure-function analysis to confirm its reverse transcriptase catalytic domain (Aim 1.1). I will next use immunofluorescence to visualize if PolZ recruitment to breaks is dependent on its scaffolding subunit REV1 and on the presence of RNA (Aim 1.2). The second part of my research will elucidate RT-DSBR activity via an mRNA donor transcribed at the site of the break (Aim 2). I will detect if RT-DSBR occurs endogenously at highly transcribed genes by using intron loss as a proxy for the use of a spliced mRNA repair template (Aim 1.2). Finally, I will validate CRISPR-Cas9 screen hits via the intron loss assay to determine which proteins are involved in various steps of the RT-DSBR pathway (Aim 2.2). Elucidating new roles for RNA and reverse transcription in DSB repair would expand the fields of genome integrity and could lead to potential new targets for cancer therapy. Since RT-DSBR would be a more accurate repair pathway in post-mitotic cells that only rely on the error-prone NHEJ, this research could also elucidate novel DNA repair in cells like neurons.

NIH Research Projects · FY 2025 · 2025-09

Project Summary Apolipoprotein E4 (E4) is the predominant genetic risk factor for Alzheimer’s disease (AD). Recent studies demonstrate that E4 contributing to tau-induced neurodegeneration. However, the mechanisms by which E4 contributes to tau toxicity remain poorly understood. The GAS-STING-Interferon (IFN) signaling pathway is known to exacerbate the immuno-inflammatory response, worsening the procession neurodegenerative diseases. In AD, pathogenic tau can induce cGAS-STING-IFN signaling in microglia. Importantly, inflammatory responses, such as IFN, are heightened in microglia expressing E4, suggesting a potential mechanistic association between E4 and IFN pathway. Cholesterol 25-hydroxylase (CH25H) is an interferon inducible gene (ISG) predominantly expressed in disease associated microglia, where it produces 25-hydroxycholesterol (25- HC), a bioactive lipid involved in immune regulation. We previously showed that 25-HC exacerbates, while deletion of Ch25h suppresses, microglial inflammatory response. Notably, E4 promotes a stronger 25-HC- dependent IL1b/a cleavage compared to E3 or E2. Our preliminary studies suggest that Ch25h deletion mitigates tau pathology, reduces neurodegeneration, and improves cognitive function in tauopathy mouse models. These protective effects are linked to suppressed microglial inflammatory signaling and reduced STING expression in vivo and in vitro. These results suggest that 25-HC may regulate cGAS-STING signaling, a pathway implicated in tauopathy in our previous studies. Based on these observations on 25-HC and APOE, we hypothesize that CH25H acts with APOE4 to activate microglial STING-IFN signaling and promote Tau toxicity and neurodegeneration in AD. Aim 1 will investigate how 25-HC promotes cGAS-STING-Inflammasome signaling in microglia, by characterize the dose-dependent effects of exogeneous 25-HC in cGAS-STING-IFN activation, investigating whether 25-HC activates the STING-inflammasome pathway and exploring alternative mechanisms involving cytosolic dsDNA accumulation using unbiased multi-omics approaches. Aim 2 will determine if E4 activates cGAS-STING-IFN via an CH25H-dependent mechanism by characterizing the effects of E4 on tau- induced IFN responses in microglia and assess if E4 activates cGAS-STING signaling at baseline and under tau fibrils stimulation, investigating whether CH25H mediates E4-induced IFN response in microglia, and determining if intracellular cholesterol dysregulation is the convergent mechanism for Ch25h and E4. Aim 3 will investigate if CH25H enzymatic activity is required for E4-induced toxicity in tauopathy mice and assess the therapeutic potential of CH25H inhibition using antisense oligonucleotides (ASOs) by leveraging newly established mouse models with enzyme-active and enzyme-inactive CH25H overexpression to examine the role of 25-HC in tauopathy mice expressing E4 (TE4). We have assembled a highly complementary and collaborative research team to address these aims. We anticipate that our study will identify novel cellular mechanisms, uncover innovative pathways, and provide new models that have therapeutic implications.

NIH Research Projects · FY 2025 · 2025-09

Abstract Autism Spectrum Disorder (ASD) research, particularly in light of its increasing prevalence and societal impact, requires rigorous replication and validation (R&V) to ensure that scientific findings are reproducible, generalizable, and applicable across diverse populations and settings. We propose an independent Autism Replication, Validation, and Reproducibility (AR²) Center in response to the NIH Autism Data Science Initiative (ADSI) Task IV, “Model Validation or Method Replication”. The primary goal of AR² is to ensure that every ADSI-generated resource is paired with an AR²-certified, complete, standalone package—fully aligned with FAIR (Findable, Accessible, Interoperable, and Reusable) principles—that enables independent reproduction of data generation, aggregation, or modeling processes in external environments and supports transparent, verifiable downstream analyses by the broader autism research community. AR² builds upon the nationally recognized Cornell Center for Social Sciences (CCSS) Data and Reproduction Archive, a CoreTrustSeal-certified infrastructure with a data archive and results replication (R2) pipeline that has archived over 2,150 studies and replicated more than 130 published datasets since 1982. Expanding on this proven infrastructure, AR² will establish a standardized, co-ownership pipeline with ADSI teams to collaboratively define R&V scope, success criteria, and deliverables; execute internal and external validation where applicable; and deliver certified R&V packages, including annotated code, test datasets, metrics, and compliance documentation (Aim 1). AR² will draw upon large-scale, racially, and geographically diverse autism-relevant data sources—including the INSIGHT Clinical Research Network, PEDSnet, PCORnet, Inovalon, and Medicaid claims datasets—to support robust validation and generalizability evaluation. Throughout the ADSI funding period, AR² will promote R&V best practices across the autism research community through targeted training and workshops and will coordinate closely with ADSI program staff, project teams, and a Community Advisory Board to ensure alignment with evolving scientific and community priorities. Final deliverables will be disseminated through accessible, trusted repositories to maximize transparency and impact (Aim 2). By applying standardized, FAIR-aligned workflows, leveraging a nationally recognized R&V infrastructure, and utilizing diverse datasets spanning racial/ethnic, geographic, and socioeconomic groups, AR² will rigorously replicate, validate, and document the generalizability of individual ADSI projects. Through these efforts, AR² will foster a culture of open, reproducible autism research and accelerate the translation of autism data science into clinical practice and policy.

NIH Research Projects · FY 2025 · 2025-09

Abstract Pediatric HIV continues to be an important public health concern in resource-limited areas. While antiretroviral therapy (ART) to pregnant and breastfeeding women has significantly reduced the rate of vertical transmission, in 2022, 130,000 new pediatric HIV infections occurred. Strategies that can complement ART, such as immune-based interventions, are critically needed to achieve the goal of a generation free of HIV. Animal studies and recent clinical trials have demonstrated the potential for passive immunization with broadly neutralizing antibodies (bnAbs) in HIV prevention. This strategy is especially suitable when transmission risk is well-defined in time such as during breast milk transmission, which accounts for almost 50% of pediatric infections. To advance the clinical development of this promising strategy, it is critical to define biomarkers of efficacy that can be used as a surrogate of protection in clinical trials to predict its efficacy. The predicted serum neutralization 80% inhibitory dilution titer (PT80) is a recently developed biomarker that integrates the IC80 and the serum concentration of the administered bnAb. In the adult AMP clinical trials, which evaluated the efficacy of the bnAb VRC01 for the prevention of sexual transmission of HIV in heterosexual women and in men who have sex with men, PT80 was strongly associated with the level of prevention efficacy. Moreover, PT80 has been associated with efficacy of single bnAb passive immunization in non-human primate models of sexual transmission. Yet, PT80 has not been validated in the setting of oral transmission or to date there is no biomarkers that predict the preventive efficacy of combination bnAbs. Using an infant non-human primate model of breast milk transmission, this project will test the hypothesis that PT80 or another biomarker can predict the efficacy of combination bnAb passive immunization for the prevention of breast milk HIV transmission. The specific aims are: 1) Engineer and characterize SHIVs expressing the Env of breast transmitted founder viruses; 2) Evaluate the ability of PT80 to predict the efficacy of passive immunization with a single bnAb in the setting of repeated oral breast milk TF SHIV exposure; and 3) Identify correlates of protection in the setting of combination bnAb and oral exposure to a virus swarm. By defining a biomarker that predicts the efficacy of bnAbs against breastmilk HIV acquisition, this study will provide novel insights for the design of clinical trials evaluating bnAb immunotherapy for the prevention of postnatal HIV acquisition; notably by 1) allowing for informed selection of bnAbs and combination bnAbs for clinical evaluation; 2) allowing for rationale design of an efficacy trial of a combination bnAb regimen to prevent breastmilk acquisition in infants, with the goal of licensure, and 3) ultimately, allowing cost saving 'surrogate endpoint' trials of bnAbs/combo bnAbs, as support for regulatory approval.

NIH Research Projects · FY 2026 · 2025-09

Abstract Lysosomes are important for maintaining cellular health and their dysfunction is linked to numerous aging-related diseases. Lysosome function is regulated by homeostatic mechanisms that allow cells to sense lysosomal stress and either eliminate or repair damaged lysosomes, or generate new lysosomes through transcriptional activation. Our research has shown that lysosomal stress is sensed through a mechanism that involves the direct modification of lysosomal membranes by autophagy proteins called ATG8s, through a process called Conjugation of ATG8s onto Single Membranes (CASM). This mechanism coordinates the turnover of damaged lysosomal membranes through microautophagy with the biogenesis of new lysosomes, but how these different activities are balanced to maintain lysosomal health is not well understood. We have shown that membrane turnover and biogenesis are regulated through separable mechanisms, and that the induction of biogenesis, which occurs through activation of the transcription factor TFEB, occurs only at particular stress thresholds that engage turnover across a lysosome network. The long-term goal of this research program is to elucidate how lysosomal stress is mitigated by lysosome turnover and biogenesis and to uncover how these activities are balanced to maintain lysosomal health. In my predoctoral research (Aim 1), I propose to test the hypothesis that lysosome biogenesis is coordinated with turnover by a threshold mechanism that engages biogenesis only at significant levels of stress, and I will seek to uncover this regulation in neurons and other cell types. Specific Aim 1.1 will determine how biogenesis is activated by stress thresholding in response to signaling through CASM, and Specific Aim 1.2 will explore this mode of regulation in normal and diseased human cortical and dopamine neurons. My postdoctoral research (Aim 2) will study organelle stress signaling and mechanisms of biogenesis in aging-related neurodegenerative or other diseases using physiologic models like iPSC neurons and also animal models like mouse or even fish. Overall, these two projects will uncover significant new insights into the cellular dysfunctions that underlie the development of aging-related diseases, and will reveal new knowledge about how lysosome function can be maintained or even restored in aging or diseased cells. The research and training plan outlined in this proposal will be completed with the mentorship of Dr. Michael Overholtzer at the Memorial Sloan Kettering Cancer Center (MSK) along with a collaborative team that has the expertise to support the proposed studies. MSK's world class research environment and abundant resources in conjunction with the support of the Weill Cornell Graduate School will guarantee the successful completion of the proposed research and career development plans.

NIH Research Projects · FY 2025 · 2025-09

PROJECT SUMMARY Adult-onset neuronal ceroid lipofuscinosis (ANCL) is a fatal lysosomal storage disorder known to be caused by autosomal dominant mutations (CSPαL115R, CSPαL116del) in the gene encoding cysteine string protein-alpha (CSPα). There are currently no treatments that can reverse or slow ANCL progression, which leads to progres- sive cognitive and motor impairment, epileptic seizures, dementia, and premature death. CSPα has no estab- lished connection to lysosomal function and is known to form a chaperone complex with SGT (small glutamine- rich tetratricopeptide repeat-containing protein) and Hsp70/Hsc70 (heat shock protein/cognate protein 70 kDa), which chaperones the synaptic SNARE protein SNAP-25. My preliminary data establishes SNAP-23, a homo- log of SNAP-25, as a previously unknown client of the CSPα/SGT/Hsc70 chaperone complex. This interaction was found via (i) immunoprecipitation of CSPα from wild type mouse brain followed by tandem mass spectrom- etry identification of SNAP-23, (ii) reduced SNAP-23 protein levels in CSPα knockout (CSPα-/-) mouse brains, and (iii) co-immunoprecipitation of SNAP-23 with each member of the CSPα/SGT/Hsc70 chaperone complex. Importantly, SNAP-23 forms a SNARE-complex with VAMP7 and syntaxin-4, the formation of which mediates Ca2+-dependent lysosomal exocytosis. Accordingly, I found diminished Ca2+-dependent lysosomal exocytosis in CSPα-/- primary neurons by measuring cell surface exposure of the LAMP-1 luminal domain. This preliminary data provides a novel, direct link between ANCL mutations in CSPα and the lysosomal pathology observed in ANCL, via impaired SNAP-23 function. The proposed study aims to (a) delineate the specific molecular mecha- nism(s) by which CSPα mutations impair SNAP-23 function, leading to the lysosomal pathology of ANCL, and (b) to evaluate the lysosomal SNARE-protein SNAP-23, a novel client of the CSPα/SGT/Hsc70 chaperone complex, as a potential therapeutic target for ANCL. I hypothesize that ANCL-causing mutations CSPαL115R and CSPαL116del reduce the ability of the CSPα/SGT/Hsc70 complex to effectively chaperone lysosomal SNARE protein SNAP-23, leading to defects in SNARE-complex assembly and lysosomal exocytosis which can be rescued by increasing SNAP-23 protein levels. In this proposal, aim 1 will examine how ANCL-causing mutations in CSPα impact the ability of the CSPα/SGT/Hsc70 complex to chaperone SNAP-23, and how loss of CSPα chaperone activity impacts SNAP-23 stability, lysosomal SNARE-complex assembly, and lysosomal exocytosis. Aim 2 will evaluate the potential of genetic and pharmacological strategies that in- crease SNAP-23 protein levels to rescue (a) SNARE-complex and lysosomal defects resulting in primary neu- rons from CSPα-/- mice and (b) premature lipofuscinosis and neurodegeneration in CSPα-/- mice. Successful completion of these studies will inform the development of rational therapeutic strategies for ANCL patients.

NIH Research Projects · FY 2025 · 2025-09

PROJECT SUMMARY The cochlear nerve, critical for hearing, relies on precise extension and connectivity during development. Cochlear nerve deficiency (CND) is a congenital malformation resulting in an absent or small cochlear nerve that leads to severe or profound hearing loss with permanent and detrimental effects on patient quality of life. To better understand CND pathophysiology, the mechanisms guiding cochlear nerve development must be understood. This project’s objective is to determine how the in vivo tissue environment impacts cochlear nerve development, using the zebrafish posterior lateral line nerve (pLLN) as a model. Similar to processes in the mammalian cochlea, the zebrafish pLLN extends alongside a migrating cell collective called the primordium. Our hypothesis is that secreted signals from the primordium contribute to the dynamics of adhesive signaling in pLLN development. These mechanisms will be investigated in zebrafish by integrating in vivo imaging of fluorescently labeled growth cones and primordium cells with genetic and experimental manipulations. In Aim 1, the role of specific adhesion molecules in the co-migration of the pLLN and primordium will be characterized. Aim 2 will examine how the location and timing of secreted cues impact pLLN extension and adhesion to the primordium. Lastly, Aim 3 will focus on mapping the progressions in gene expression of neurons forming the pLLN and the cells of the primordium over time as a way to evaluate the relative composition of intercellular signaling. These studies will clarify how adhesive and secreted cues cooperate to ensure robust pLLN development, offering insight into the developmental process of the cochlear nerve. Findings in these areas support the search for future therapeutic targets for CND. The described studies will be carried out under the direct mentorship of Dr. A. J. Hudspeth at The Rockefeller University within the supportive Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program environment. This fellowship constitutes an important career milestone for dual-degree students seeking to become independent investigators.

NIH Research Projects · FY 2025 · 2025-09

Dr. Lily Yan is a general internal medicine physician committed to a long-term career working at the intersection of environmental health and global cardiovascular disease (CVD) prevention. Environmental lead pollution is an emerging risk factor for heart disease, particularly in low-income countries. Dr. Yan’s research identified adults in urban Haiti have high blood lead levels (BLL) that are 5-fold higher than the US, higher BLL are associated with elevated blood pressure, and heart failure is the predominant type of CVD and associated with hypertension. She hypothesizes lead exposure may be associated with heart failure, which is currently unknown. She proposes a high-impact career development award to expand her training and research to characterize the association of lead with incident heart failure and CVD, and to identify modifiable sources and potential interventions for future exposure reduction in Haiti. Her training aims build expertise in 1) environmental health including pollution exposure assessment and 2) implementation science methods, including qualitative research and mixed methods to identify future interventions to reduce lead exposure. Her career development plan includes coursework, experiential learning, and a multidisciplinary mentorship team with decades of experience in global CVD research, environmental health, and implementation science. She is supported by a robust research and training environment in Haiti and the US that leverages a 45+ year clinical-research program with continuous NIH funding and ongoing studies. Dr. Yan’s research plan includes Aim 1: evaluating the association of BLL with incident heart failure and CVD, over a median follow-up time of 7 years, and Aim 2: identifying modifiable lead sources and potential interventions to reduce individual, household, and community exposure, guided by the Exploration- Preparation-Implementation-Sustainment framework. For sources, she will conduct a lead exposure assessment using XRF analyses among 100 participants with high BLL and 100 with low BLL. For future interventions, she will conduct interviews with participants and stakeholders to explore preferences, barriers, and facilitators for interventions. Data will be integrated using explanatory sequential mixed methods and intervention mapping to identify prioritized interventions for future evaluation. This proposal builds upon her training aims, and is a sub-study in the ongoing Haiti CVD Cohort (R01 HL143788). This K23 is the first step to address global knowledge gaps in the relationship between environmental lead, heart failure and CVD in settings of extreme poverty and will generate data-driven environmental pollution intervention(s) aimed at reducing premature CVD. Her proposal is highly feasible and sets her career pathway towards independence in an emerging field that is high-impact for global CVD population health.

NIH Research Projects · FY 2025 · 2025-09

Project Summary / Abstract Coronary artery bypass grafting (CABG) is the most commonly performed adult cardiac surgery procedure, and the standard of care for patients with severe coronary artery disease. CABG can be performed using either arterial or venous grafts, with arterial grafts being associated with better outcomes in observational studies, but not in the only published randomized trial. The Randomized comparison of the Outcomes of single vs Multiple Arterial grafts (ROMA) trial will evaluate whether multiple arterial grafts (MAG) compared with single arterial graft (SAG) have better outcomes in the general CABG population (84.5% men). Women represent a minority of patients in CABG trials, and there are important biological and surgical differences between men and women undergoing CABG, so that ROMA as currently funded will not allow a meaningful assessment of the effect of MAG in women. However, ROMA provides a unique opportunity to leverage the existing trial infrastructure to realize the first cardiac surgery trial dedicated to women (ROMA:Women). By enrolling 2,000 women, we will have enough statistical power to determine 1) the impact of MAG vs SAG on major adverse cardiac and cerebrovascular events in women undergoing CABG and 2) the impact of MAG vs SAG on generic and disease-specific quality of life (QOL) as well as physical and mental health symptoms in women undergoing CABG. Enrolled patients are randomized 1:1 to MAG or SAG. The inclusion and exclusion criteria, the interventions, outcome definitions and the follow-up protocol are identical to those of the ROMA trial. The only exception is that the 70 years age cut-off that was used in ROMA and will not be used in ROMA:Women. ROMA:Women leverages the existing ROMA infrastructure including clinical trial unit, database, case report forms, randomization system, site training resources, regulatory approvals, network of participating sites, and study coordinators. The trial primary outcome is a composite including death, stroke, non-procedural myocardial infarction, repeat revascularization and hospital readmission for acute coronary syndrome or heart failure at a minimum follow-up of 2.5 years. The secondary outcome is the absolute change in the Seattle Angina Questionnaire (SAQ) at 12 months compared to baseline. The trial is designed to have >90% power to demonstrate a 25% relative risk reduction in the primary composite outcome in the MAG group. Generic QOL (SF-12, EQ-5D), and symptoms (PROMIS-29) as well as key clinical events will also be captured.

NIH Research Projects · FY 2025 · 2025-09

PROJECT SUMMARY/ABSTRACT Substance use disorder (SUD) due to drugs other than alcohol, which affects 9% of adults in the United States, is a significant public health concern contributing to substantial morbidity and mortality, resulting in over 100,000 overdoses in 2022 alone. While effective SUD treatment exists, fewer than 25% of people with SUD receive treatment. Peer support services (PSS) offer a potential avenue for enhancing SUD treatment and outcomes, with the goal of helping people with SUD initiate and remain engaged in the recovery process. These services, delivered by trained and credentialed peer specialists who have firsthand experience with SUD, encompass a wide range of support services, including recovery planning, community linkages, and social and emotional support services. PSS are unique to other types of care navigation in that they emphasize improving clients' psychosocial skills, including resilience, coping, and empowerment. PSS, which use a recovery coaching model, are also distinct from the peer support provided by uncredentialed sponsors in 12- step facilitation. Growing adoption of PSS has outpaced the evidence on the effectiveness of PSS, which is limited and mixed. Nowhere is this more evident than with Medicaid, the largest payer of SUD treatment services in the U.S. Medicaid is an innovator in coverage of PSS. In 2024, 41 state Medicaid programs covered PSS for adults with SUD, increasing from only 26 states in 2017. Medicaid's substantial expansion of PSS coverage and the urgent need for SUD treatment services within the Medicaid population creates an opportunity to rigorously evaluate the impact of receiving PSS on SUD treatment and SUD-related adverse outcomes. Furthermore, the COVID-era Medicaid policy changes that expanded telehealth coverage provide an avenue to compare the effectiveness of telehealth PSS relative to in-person delivered PSS. The overall goals of this study are to provide robust evidence on whether and how PSS impact SUD treatment engagement and outcomes and to inform the design of PSS coverage policy in Medicaid and other insurance programs. We will focus on the following specific aims to achieve these objectives: (1) Assess the impact of Medicaid-covered PSS on SUD treatment initiation, engagement, and retention among Medicaid beneficiaries with SUD, (2) Assess the impact of Medicaid PSS on adverse events including SUD-related emergency department visits, unplanned inpatient readmissions, and drug overdose among Medicaid beneficiaries with SUD; and (3) Characterize how Medicaid PSS coverage policies can influence PSS implementation for Medicaid beneficiaries with SUD. This proposed mixed-methods study will use a concurrent-embedded approach, such that quantitative results (Aims 1-2) will inform qualitative analyses (Aim 3) and vice versa at various points in the study. Study findings will build evidence on the impact of PSS on SUD treatment and overdose and inform the rapidly evolving landscape of PSS policy and implementation.

NIH Research Projects · FY 2025 · 2025-09

Project Summary/Abstract Mechanistic target of rapamycin complex 1 (mTORC1) is a major cytosolic regulator of cellular anabolism and governs many downstream metabolic processes. Mitochondria are semi-autonomous organelles that are major hubs of compartmentalized biochemical reactions within cells. While the role of mTORC1 in coordinating metabolic balance in the cytosol are consistent with its ability to sense and respond to perturbations in the cellular nutrient state, the effect of mTORC1 on mitochondria remain poorly defined. To identify how mitochondria are impacted by loss of mTORC1 signaling, I performed quantitative proteomic analysis on immunopurified mitochondria from cells treated with mTORC1 inhibitors and identified several proteins involved in mitochondrial lipid homeostasis. We identified PRELI Domain Containing 1 (PRELID1) as an essential, short-lived mitochondrial protein that is downregulated upon mTOR inhibition. While mTORC1 is active in the cytosol, it remains unclear how the stability of PRELID1 in mitochondria is affected. In my preliminary work, I identified that inhibition of proteasome function protects PRELID1 against degradation induced by mTOR inhibition. To identify the genes responsible for this phenomenon, I developed a CRISPR/Cas9 genetic screening approach to individually knock out components of the Ubiquitin-Proteasome system (UPS) and interrogate how mTOR status in the cytosol maintains stability of PRELID1. The top-scoring gene in my preliminary genetic screen was Seven in Absentia Homolog 1 (SIAH1), an E3 Ubiquitin ligase with previously reported mitochondrial targets. I hypothesize that mTORC1 regulates mitochondrial lipid homeostasis, in part, through the action of SIAH1 and that this axis may be a suitable drug target in metabolic diseases such as nonalcoholic fatty liver disease (NAFLD). A lack of insight into the mechanistic role of mTORC1 in regulating mitochondrial function precludes investigation of this hypothesis. In this proposal, building on my preliminary work, I will test the hypothesis that mTORC1 regulates mitochondrial function by regulating the lipid composition of mitochondria. In Aim 1, I will investigate the mechanism by which mTORC1 regulates mitochondrial lipid homeostasis. In Aim 2, I will determine how mTORC1 orchestrates mitochondrial lipid homeostasis in mouse liver models and the role cardiolipin plays in the pathogenesis of NAFLD. I anticipate that these studies will determine: 1) the mechanistic role of SIAH1 in shaping mitochondrial function under metabolic stress and 2) the contribution of mitochondrial dysfunction to the development and progression of NAFLD. The work and training plan outlined in this proposal will be completed in the laboratory of Dr. Kivanc Birsoy at the Rockefeller University and will best prepare me for a career as an independent academic physician-scientist.

NIH Research Projects · FY 2025 · 2025-09

SUMMARY Alzheimer's disease (AD) and related dementias involve multifactorial and interconnected mechanisms, including APP/amyloid-β (Aβ) pathology, tauopathy, neuroimmune responses, neuronal impairments, and glial alterations. Mitochondrial dysfunction is an early event influenced by various disease-related factors, including Aβ and apolipoprotein E4 (APOE4), the strongest genetic risk factor for late-onset AD. Mitochondria produce energy, but are also a major source of reactive oxygen species (ROS). Mitochondrial ROS (mtROS) increase in aging and disease, are associated with pathogenic processes, including protein misfolding, synaptic deficits, and neuroinflammation, and can diffuse to other subcellular compartments to signal and influence metabolic, redox and health status. Complex III (CIII) of the mitochondrial respiratory chain has the largest capacity for ROS production and can release ROS toward the intermembrane space and extra-mitochondrial compartments, thus poising CIII-derived ROS (CIII-ROS) to affect signaling pathways and nuclear functions. However, the mechanisms by which CIII-ROS may influence nuclear processes and affect AD pathogenesis are not defined. Astrocytes are reported to produce high levels of mtROS. Thus, we examined the regulation and roles of astrocytic mtROS using live-cell redox imaging, site-selective mtROS suppressors, targeted genetic manipulations, molecular profiling, and preclinical testing, among other approaches. Our findings reveal that disease-linked factors, including Aβ, induce astrocytic CIII-ROS in a temporally defined and NF-κB-dependent manner. Induction of CIII-ROS caused selective oxidation of target proteins and amplified STAT3 activation and gene expression changes linked to astrocytic reactivity and disease responses. Suppression of CIII-ROS decreased brain pathology and neuroimmune responses, and extended lifespan in mice with tauopathy. Notably, APOE is highly enriched in astrocytes and influences mtROS levels. Our data suggest that the APOE4 variant exacerbates astrocytic mtROS responses whereas the AD-resilience variant of APOE (R136S Christchurch) inhibits these responses. However, the exact effects of APOE variants on astrocytic mtROS dynamics and the roles of mtROS in gene regulation and dementia risk are not clear. In the current project, we will examine the underlying mechanisms and effects of astrocytic mtROS-nuclear crosstalk in neural cultures and knock-in mouse models. We will define mtROS responses and their regulation and roles using cutting-edge live-cell imaging, multiomic profiling, functional measures, and other complementary methods. Together, our study will leverage advanced model systems and technologies to identify new molecular networks mediating mitochondrial-nuclear crosstalk and reveal novel redox-linked therapeutic strategies for AD and related neurodegenerative disorders.

NIH Research Projects · FY 2025 · 2025-09

PROJECT ABSTRACT Hematopoietic stem and progenitor cells (HSPCs) carry the important responsibility of producing an enormous number of myeloid and lymphoid cells. Defects in HSPC function can lead to benign and malignant neoplasms as well as bone marrow failure, often driven by somatic mutations in key regulators. Noncoding (nc)RNAs are emerging regulators of hematopoietic self-renewal and lineage specification. Long (l)ncRNAs specifically contribute by modulating genome topology, chromatin compaction, gene transcription, post-transcriptional processing, translation, and cellular signaling. In addition, transfer (t)RNAs, which shuttle amino acids to the ribosome, shape the cellular proteome by enhancing the translation of messenger RNAs enriched for cognate codons. When dysregulated, these ncRNAs contribute to the pathogenesis of hematologic neoplasms. Despite these advances, ncRNAs are not profiled in standard single-cell RNA sequencing (scRNAseq): ncRNAs are mostly not endogenously polyadenylated (EPA), preventing their capture by oligo-deoxythymidine primers. This limitation of scRNAseq critically prevents the study of how ncRNAs bias and commit cells toward hematopoietic lineages. We hypothesize that ncRNAs, particularly lncRNAs and tRNAs, bias HSPCs toward specific cellular fates. To test this hypothesis, we developed a method, single-cell total RNA sequencing (scTRS), that incorporates RNA de-modification and exogenous polyadenylation to extend RNA capture to modified and non- EPA ncRNAs, which are not captured by other methods. Here, first, I aim to develop a computational pipeline to enable the processing and analysis of scTRS data. Second, I will apply scTRS in primary HSPCs to identify candidate ncRNA drivers of normal hematopoiesis. Then, I propose a series of in vitro perturbation experiments to validate and examine the roles of these candidate drivers of normal differentiation. Finally, because the scTRS workflow is compatible with commercially available droplet-based platforms and the computational pipeline will be broadly shared, scTRS will be available to research groups across fields for broad impact. Collectively, this work will deliver novel and actionable insights into how ncRNAs help orchestrate human hematopoiesis.

NIH Research Projects · FY 2025 · 2025-09

Project Abstract Acute Respiratory Distress Syndrome (ARDS) is a devastating disease with high morbidity and mortality. The COVID-19 pandemic and the yearly toll of viral and bacterial pneumonia underscore the urgent need for a mechanistic understanding of ARDS that would lead to new therapies. ARDS is characterized by a prothrombotic state and activation of the thrombin receptor protease activated receptor 1 (PAR1). PAR1 is perhaps the most important mediator of inflammation and coagulation in ARDS, as it coordinates the interplay between platelets, endothelial cells, and the immune response. However, targeting PAR1 therapeutically has thus far been unsuccessful, highlighting our knowledge gaps in understanding the pleiotropic roles of this critical receptor. The premise of proposal is that PAR1 plays a previously unappreciated role in the lymphatic vasculature in ARDS that offers a novel therapeutic strategy to prevent lung injury. The lymphatic vasculature mediates the inflammatory response of the lung through both fluid drainage and trafficking of immune cells. However, the molecular pathways that drive these functions have not been fully uncovered. Lymphatics have specialized endothelial cell junctions that mediate fluid and cell uptake into the vessel lumen. Loss of these permeable ‘button’ junctions impairs lymphatic function by preventing the drainage and cell trafficking function of these vessels. Using mouse models, we have found that PAR1 is necessary for button junction formation during lung injury. Lymphatic-specific loss of PAR1 leads to immune cell accumulation and worse lung injury, which our studies suggest is due to loss of button junctions that promote lymphatic function. These data point to a previously unknown role of PAR1 in lung injury that improves lymphatic drainage and promotes resolution of inflammation. In this proposal, we will test the hypothesis that PAR1 is necessary for lymphatic buttons and function (Aim 1), that thrombin-mediated PAR1 signaling in lymphatics is protective during lung injury due to its role in promoting lymphatic buttons and drainage (Aim 2), and that agonists of PAR1 that promote beneficial PAR1 signaling in lymphatics while persevering blood vessel function are a novel therapeutic strategy for ARDS (Aim 3). When completed these studies will result in an entirely new paradigm for the pathogenesis of ARDS by uncovering a link between PAR1, lymphatic function, and the inflammatory response, leading to a novel therapeutic strategy for this devastating disease.

NIH Research Projects · FY 2025 · 2025-09

PROJECT SUMMARY/ABSTRACT Over 550,000 Americans have end-stage kidney disease (ESKD) requiring dialysis and patients with ESKD have very high rates of hospitalization and skilled nursing facility (SNF) admission. Transitions of care between acute and post-acute settings can be suboptimal because patients with ESKD have a high degree of medical complexity. Suboptimal hospital-to-SNF care transitions likely contribute to the very high hospital readmission rates (33%) among patients with ESKD. Hospitalizations, readmissions, and SNF stays for patients with ESKD account for >$10 billion in Medicare spending. Although SNF admissions are common and costly among patients with ESKD, very little is known about hospital-to-SNF care transitions in this population. The choice of SNF and whether dialysis is available on-site can shape both the continuity and quality of dialysis care. For example, it is unknown how commonly patients with ESKD receive hemodialysis treatments on-site at the SNF, off-site at the same dialysis facility they used prior to hospitalization, or off-site at a different dialysis facility during the SNF stay. It is also unknown how often patients receiving peritoneal dialysis (the dominant form of home dialysis in the US) are able to continue peritoneal dialysis while admitted to a SNF vs. having to transition to hemodialysis and whether such transitions are temporary or sustained. Optimizing hospital-to-SNF care transitions among patients with ESKD is crucial to improve quality of care for this medically complex population. In Aim 1, we will characterize patterns of hospital-to-SNF care transitions among patients with ESKD using Medicare claims and identify patient, dialysis facility, SNF, and market characteristics associated with those patterns. Aim 2 will examine the association of hospital-to-SNF care transitions patterns for patients with ESKD with established measures of quality of care (e.g., discharge home, 30-day readmissions, 30-day ED visits, functional improvement, pain, mortality). Our central hypothesis is that there will be significant variation in continuity and quality of care by patient, dialysis facility, SNF, and market characteristics, and that on-site hemodialysis and off-site hemodialysis with continuity will be associated with better outcomes, compared to not having continuity in outpatient dialysis facilities. Aim 3 will elicit the qualitative experiences and perspectives regarding hospital-to-SNF care transitions of patients with ESKD and their clinicians. In semi-structured interviews informed by care transitions conceptual frameworks, we will seek to understand ESKD care transition experiences and identify opportunities for improvement. Findings from this research will generate the first national data on hospital-to-SNF care transitions among patients with ESKD while building foundational insights that will inform future interventions to improve care transitions in this population.

NIH Research Projects · FY 2025 · 2025-09

Overall Project Summary: Our mission is to facilitate translational and basic research on polycystic kidney disease and related disciplines by providing access to accurate, reproducible, comprehensive measurements of all features of PKD visible on human clinical imaging (abdominal pelvic MRI and CT). This proposal builds upon a long tradition of pioneering PKD imaging research by our investigators who have been at the forefront of PKD imaging. We propose a biomedical research core that will comprehensively label images of ADPKD subjects enrolled in research or being considered for research projects. ADPKD subject image labeling will be optimized for highly accurate and reproducible Image Phenotyping by providing access to an essential “toolbox” for extracting imaging biomarkers from PKD subjects. We also provide imaging expertise tailored specifically to PKD research and access to ADPKD image data. The PKD Image Phenotyping Repository Core, will fully label and store in one secure location, all research images on PKD-RRC Core Center subjects and 400 existing subjects in our Rogosin ADPKD Data Repository, CRISP study images and more ADPKD subjects as they enroll or utilize this core. This includes annotations of 0rgans/cysts/fat/muscles for providing reports to the contributors on these critical imaging biomarkers (e.g., renal and extrarenal organ volumes, cyst volumes). This database of annotated images will empower imaging and PKD scientists to explore analytical improvements in noninvasively characterizing and measuring the anatomic features of ADPKD within all organs and tissues visible on abdominal-pelvic MRI and CT. These quantitative measurements will assess disease progression and responses to treatment within individual subjects. This proposal addresses a critical need in the PKD imaging research pipeline, from the basic science of image analysis to clinical investigation of this systemic disorder and assessing response to treatments. In addition, core leaders will pioneer solutions to the needs of PKD researchers. We expect this strategy will continue our proven track record of supporting high-impact science nationally. These activities will be organized by an Administrative Core that leverages the resources of Cornell University. Our commitment to the principle of collaborative science includes streamlining procedures for collecting and sharing images, imaging biomarkers, and expertise, integrating core activities, and collaborating with other RTCCs within the PKD Research Consortium.

NIH Research Projects · FY 2025 · 2025-09

Project Summary In the development of atherosclerotic plaques, macrophages infiltrate the intima of the aortic wall to digest modified lipoproteins. Over time, these macrophages become lipid laden foam cells. Most modified lipoproteins are aggregated and crosslinked to the extracellular matrix of the vessel wall, which prevents them from being phagocytosed by macrophages. We have described how macrophages digest aggregated LDL extracellularly using a process termed digestive exophagy. Macrophage first form a sealed, acidified extracellular compartment around aggregated LDL. Lysosomes are then secreted into this compartment, allowing lysosomal acid lipase to hydrolyze cholesteryl esters into free cholesterol. However, it remains unclear how this excess extracellular free cholesterol is transported into macrophages for lipid droplet formation. Moreover, recent cell-lineage analyses showed that most foam cells found in plaques are of smooth muscle cell origin and not macrophages. This discovery is intriguing because smooth muscle cells are not capable of digestive exophagy. My proposed research aims to elucidate the molecular mechanisms that can help address these two existing research questions, which would provide alternative mechanisms for foam cell formation. Based on my preliminary results, I hypothesize that the cholesterol transport protein, STARD4, can mediate the transport of free cholesterol from the plasma membrane of macrophages to the ER for lipid droplet biogenesis (Aim 1). In Aim 1.1, I propose to investigate changes in HDL metabolisms in STARD4 knockout macrophages with lipid mass spectrometry. In Aim 1.2, I will examine if the in vitro finding would translate to a delay in plaque formation in mouse models. Furthermore, I hypothesize that the lysosomal cholesterol transport proteins NPC1 and NPC2 can help transporting and inserting free cholesterol from the extracellular compartment to the plasma membrane of macrophages (Aim 2). Finally, I hypothesize that smooth muscle cells turn into foam cells by absorbing free cholesterol released by neighboring macrophages during digestive exophagy (Aim 3). My proposed studies will expand our understanding of the basic biology of Mϕ-agLDL interactions – a poorly understood and often overlooked process that underlies the development of atherosclerotic plaques. My pilot studies on STARD4 demonstrated that loss of STARD4 specifically impaired aggregated LDL-mediated foam cell formation and not acetylated LDL-mediated foam cell formation. Thus, the characterization of how extracellular free cholesterol released from digestive exophagy enters Mϕs and contributes to foam cell formation would open an avenue for novel therapeutic approaches. Designing or identifying inhibitors that slow down the incorporation of PM free cholesterol into lipid droplets could slow down foam cell formation in a manner that is independent of current treatments, and this may provide additive effect when used in combination with current treatments.

NIH Research Projects · FY 2025 · 2025-09

PROJECT SUMMARY / ABSTRACT This K23 will provide Dr. Nupoor Narula with new skills critical for her to attain academic independence as an investigator focused on novel profiling approaches to improve therapy, risk stratification, and outcomes for patients with genetically triggered thoracic aortic aneurysms (gTAA). Extending logically on her prior track record, an integrated training plan has been developed focused on two key areas – cardiac magnetic resonance imaging (CMR) and advanced cardiovascular genetics. Applied training will be attained by leveraging an established R01, which will provide a rigorous framework in which to study impact of prosthetic aortic grafts (a cornerstone of therapy for gTAA known to be stiffer than native aortic tissue) on left ventricular (LV) and distal aortic remodeling, and whether gTAA etiology modifies impact of grafts. To test these concepts, at least 150 gTAA patients undergoing prosthetic graft replacement of the proximal aorta will be prospectively studied using cutting edge CMR methods pre- and (1 year) post-operatively, together with rigorous genotyping. LV tissue characterization will be performed using high resolution navigator and parametric mapping CMR technologies, and both 4D flow and dynamic (cine) CMR will be employed to quantify aortic vessel wall properties. In parallel, tailored genetic analyses will be performed to test if CMR-evidenced response to grafts is modified by genotypic characteristics of TAA, and validated survey methods will be used to assess outcomes. Aim 1 will test impact of native and graft-induced alterations of aortic stiffness on LV performance in gTAA, with focus on whether pre- and post- operative LV function and tissue characteristics (fibrosis) vary in relation to gTAA etiology; Aim 2 will employ innovative CMR approaches to assess distal aortic response to proximal graft implantation – including tortuosity, 4D flow derived wall shear stress, and pulse wave velocity; Aim 3 will explore phenotypic and genotypic modifiers of LV and distal aortic remodeling after proximal graft replacement, with focus on type and mechanism of pathogenic variants. Applied training will be complemented by didactic training enabled by graduate coursework in CMR physics, genetics, and translational research/statistics. K23 research and training will be attained at a leading institution for gTAA, and guided by mentors with complementary multidisciplinary expertise: Dr. Weinsaft is the principal investigator of the R01 to which this K23 is paired and has extensive experience in use of CMR in gTAA focused longitudinal outcomes studies; Dr. Wang is a co-mentor with an established track record in CMR pulse sequence development – including high resolution 3D CMR, as will be employed in the proposed research plan; Dr. Devereux is a co-mentor with longstanding expertise in gTAA – inclusive of translational genetics and LV remodeling. Findings from this K23 will address key knowledge gaps of broad significance to gTAA patients – including mechanism and patient profiles at greatest risk for adverse remodeling after prosthetic aortic graft implantation. Study results will directly inform future R01s focused genotype/CMR on use of integrated profiling to improve prediction of therapeutic response and clinical outcomes in gTAA.

NIH Research Projects · FY 2025 · 2025-09

PROJECT SUMMARY/ABSTRACT Hepatitis B (HBV) infects more than 200 million people worldwide and is the 10th leading cause of death worldwide. HBV treatment with nucleoside analogs targets the suppression of viral replication, but HBV able to persist in a reservoir of covalently closed circular (cccDNA) form during chronic infection, with the potential to reactivate upon immune suppression, aging, or cessation of treatment. As a consequence, lifelong treatment is required, and eradication and functional cure of the infection, the loss of surface antigen in serum testing, occurs at a slow rate. Moreover, HBV suppression with current therapies does not eliminate the risk of liver cancer development. HIV coinfection with HBV is common and complicates HBV outcomes, evidenced by an 18-fold increased liver-related mortality, compared to HBV alone. Novel approaches to HBV therapy are needed, particularly in people with HBV/HIV. While HIV accelerates the HBV clinical course, it also presents unique scientific opportunities as shortly after starting HBV-active antiretroviral therapy (ART), some people with HBV/HIV experience higher rates of HBsAg loss, 5 times what is seen in HBV alone. Leveraging an established clinical cohort with HBV/HIV and HBV in Zambia, we will analyze the impact of HIV-related immune suppression and restoration with ART on HBV liver reservoir and the liver microenvironment using cutting-edge spatial proteomic and transcriptomic technologies. These technologies, which are capable of delineating RNA, DNA, and protein targets without cellular or tissue dissociation at subcellular resolution, will be applied to liver biopsies from cohort participants before and during therapy, allowing us to investigate and determine cellular composition, HBV- and HIV-infected cells, spatial architecture, and the hepatic microenvironment. The resulting data will advance the development of HBV cure, particularly for people with HIV, by identifying how HIV accelerates liver pathogenesis, whether these mechanisms are normalized with ART, and virus-host interactions in the liver that mediate HBV control including FC. This line of research will validate current mechanisms being evaluated in trials and pave the way for new and emerging immunotherapies for HBV cure.