Ut Southwestern Medical Center

NIH Research Projects · FY 2026 · 2026-05

Project Summary Spatially Fractionated Radiation Therapy (SFRT) represents a significant advancement over conventional radiation therapy (CONV) by delivering a highly modulated spatial dose pattern, characterized by the peak- valley dose ratio (PVDR). Preclinical and clinical studies have demonstrated that SFRT substantially enhances the therapeutic index by improving normal tissue dose tolerance and tumor control efficacy compared to CONV. The clinical adoption of SFRT is rapidly expanding, now encompassing a variety of disease sites beyond bulky advanced tumors. This project focuses on proton minibeam RT (pMBRT), a versatile SFRT modality that is not yet clinically available, despite compelling evidence from biological studies highlighting its potential to further reduce radiation-induced normal tissue toxicity and improve tumor control compared to CONV and clinically available SFRT techniques. The overarching goal of this project is to develop the first clinical pMBRT prototype and innovative pMBRT methods to drive its clinical translation. This project leverages a well-established academic-industrial partnership (AIP) between KUMC and RaySearch. As RaySearch, the world’s leading TPS company, offers the globally used RayStation TPS, this AIP ensures the seamless translation of project outcomes to end-users, promoting clinical adoption and widespread application of pMBRT for patient benefit. This project introduces three major innovations. (1) First clinical pMBRT prototype: Building upon our preclinical pMBRT system [115,131], this project will develop the first clinical pMBRT prototype, fully integrated with RayStation TPS. This milestone will facilitate patient treatment and pave the way for widespread clinical implementation. (2) Multi-collimator pMBRT (MC-pMBRT): A fundamental challenge for implementing pMBRT in patients is how to achieve sufficient PVDR while maintaining dose objectives. To address this, this project introduces MC-pMBRT, a novel method that uses multiple pre-made, general-purpose collimators with varying minibeam geometries to jointly optimize dose and PVDR. (3) Minibeam-LATTICE: The original form of pMBRT delivers a uniform target dose. This project introduces minibeam-LATTICE, a novel SFRT modality that leverages minibeams to achieve a lattice dose pattern in the target, enabling the treatment of small-to-medium tumor targets that are unsuitable for current clinically available SFRT modalities due to their large beam size. Significance: The completion of the project will provide (1) the first clinical pMBRT prototype integrated with RayStation TPS, enabling patient trials, and (2) novel pMBRT methods, such as minibeam-LATTICE, to expand SFRT’s clinical utility to small-to-medium tumor targets, where current clinically available SFRT cannot provide a spatially-modulated dose pattern due to their large beamlet size. These advancements will enhance the therapeutic potential of SFRT, offering broader treatment options and improved outcomes for patients.

NIH Research Projects · FY 2026 · 2026-05

PROJECT SUMMARY In cancer and chronic infection, T cells develop into a dysfunctional state called exhaustion because of persistent antigen stimulation. Exhausted T cells upregulate immune checkpoints, display dysregulated metabolism, and progressively lose effector function and the ability to persist and develop immune memory. T cell exhaustion hinders the clearance of pathogens and malignant cells by the immune system and limits the effectiveness of immunotherapies such as chimeric antigen receptor (CAR) T cell therapy. Therefore, understanding how T cells adapt to chronic antigen receptor signaling is critical for developing more effective immunotherapies. A stem-like CD8 T cell subset has been identified in chronic infections and cancers. Stem-like CD8 T cells mediate long-term immunity by self-renewal and replenishing other CD8 T cell subsets. Stem-like properties in T cells are essential for the efficacy of immunotherapies. We have identified key transcription factors that regulate the differentiation of stem-like CD8 T cells. However, the molecular program underlying the adaptation of stem-like CD8 T cells to chronic antigen receptor signaling is incompletely understood. Our recent findings show that the redox sensing KEAP1-NRF2 pathway is critical for the differentiation of stem-like CD8 T cells and adaptation of CD8 T cells to chronic antigen receptor signaling. In the proposed study, we will determine how the KEAP1-NRF2 pathway regulates the adaptation of CD8 T cells to persistent antigen receptor signaling through preventing TCR hyperactivation and promoting metabolic fitness. Our study will shed important new light on the development of more potent and efficacious immunotherapies for cancers and chronic infections. Furthermore, KEAP1 and NRF2 have been extensively investigated as potential drug targets for chronic diseases. Therefore, our findings hold significant promises for informing interventions that aim at modulating this pathway.

NIH Research Projects · FY 2026 · 2026-05

Project Summary/Abstract Protein phosphorylation is the most common post-translational modification in eukaryotic cells and impacts nearly every cellular process. Despite the ubiquity of phospho-regulation and its long history of study, there remain technical challenges to accurately detecting protein phosphorylation events, particularly in multi-site phosphorylation. For example, it remains impossible to predict how or if multi-site phosphorylation will shift a proteins migration on SDS-PAGE and, as a result, detecting phosphorylated proteins by western blot requires a priori knowledge to raise a phospho-specific antibody. As SDS-PAGE is arguably the most widely used, accessible, and cost-effective means of protein analysis, advancing this technology to enable the consistent and quantifiable detection of protein phosphorylation would benefit nearly all fields of cell biology. This exploratory project will exploit a novel mechanism for chemically modifying protein phospho-sites for the purpose of developing new methods to study protein phosphorylation. Specifically, we will take advantage of the newly characterized Legionella pneumophila effector protein LnaB, which installs adenosine monophosphate (AMP) specifically onto the phosphate group of phosphorylated serine, threonine, and tyrosine. These proof-of-principle studies will determine whether LnaB can accommodate ATP analogs with an alkyne adduct (ATP-alkyne), thus facilitating click-chemistry with azide-containing molecules for the modular modification of protein phospho-sites. Towards this end, we will first identify LnaB orthologs with optimal catalytic efficiency and broad specificity phosphoryl-AMPylase activity. Subsequently, we will test whether ATP analogs with alkyne adducts (on either the adenine base or ribose) are suitable substrates for LnaB. As a proof-of-principle application, we will use this method to quantify multi-site phosphorylation. Specifically, we will install “mass tags” – azide-containing peptides of defined molecular weight – on phosphorylated proteins to quantitatively shift their mass in a manner that is linearly dependent on the number of phosphates. By combining this with SDS-PAGE, we will determine whether we can quantify multi-site phosphorylation of recombinant proteins and detect both phosphorylated and non- phosphorylated proteins with a single antibody in complex samples by western blot analysis, thus directly quantifying fraction phosphorylated. Our long-term goal is to develop a modular set of reagents for modifying phospho-proteins for unique downstream applications, including counting multi-site phosphorylation by SDS- PAGE, fluorescent labeling, streamlined western blot detection, and, in the future, modulation of specific phospho-regulatory axes to alter signaling pathways for therapeutic purposes.

NIH Research Projects · FY 2026 · 2026-05

PROJECT SUMMARY/ABSTRACT Primary Pyruvate Dehydrogenase Complex Deficiency (PDCD) is a rare but severe mitochondrial disorder, with an estimated incidence of 1 in 50,000 to 75,000 live births in North America. The majority of cases are caused by mutations in the X-linked PDHA1 gene. There is currently no curative therapy for PDHA1 deficiency, and the prognosis remains very poor, with death occurring in approximately 90% of affected individuals before the age of four. Adeno-associated virus (AAV)-mediated gene delivery has emerged as a well-established approach for treating neuromuscular and neurodevelopmental disorders. Lumbar intrathecal (IT) injection of AAV9 into the cerebrospinal fluid (CSF) has been used successfully in animal models to rescue multiple CNS diseases. Our laboratory has over 20 years of experience in developing gene therapies for more than two dozen neurological conditions. Notably, 8 gene therapy candidates originating from our lab have progressed to clinical trials, two of which (CLN7 and SPG50) entered the clinic since 2021 and are currently ongoing within the Gene Therapy Program at UT Southwestern Medical Center. We propose to use a novel AAV9 variant (AAV9fyhr) vector to deliver the PDHA1 gene to the central nervous system (CNS) in a newly developed and characterized E75A mouse model to identify the potential efficacy, as well as toxicity, of the AAV9fyhr/PDHA1 vector. Our central hypothesis is that AAV9fyhr-mediated PDHA1 gene replacement therapy will restore proper protein function and ameliorate disease phenotypes in the E75A mouse model, with the degree of benefit driven by dose and age of treatment. We will test this hypothesis by pursuing two specific aims: Aim 1. Evaluate the efficacy of AAV9fyhr/PDHA1 in the E75A mouse model of PDHA1 deficiency. E75A mice will be treated with a range of doses by lumbar IT injection, at either young or older ages. Mice will be monitored for treatment benefit by longitudinal behavioral tests and biochemical assessment of metabolic correction. Aim 2. Determine the safety of AAV9fyhr/PDHA1 in wild-type (WT) C57BL/6J mice. WT mice will receive lumbar IT injections of escalating doses of AAV9fyhr/PDHA1. Mice will be monitored in life and post-mortem for short and long term adverse effects, including comprehensive histopathology, with special attention to the assessment of dorsal root ganglia (DRG) toxicity and hepatotoxicity, two known risks associated with AAV-based therapies. If these proof-of- concept studies demonstrate favorable efficacy and no detectable toxicity, the resulting data will serve as pivotal IND-enabling efficacy evidence and supportive safety data. Building on the precedent set by our work advancing 8 gene therapies into clinical trials, in future studies we intend to leverage our extensive experience to design and carry out the remaining IND-enabling studies. If successful, these efforts are designed to ultimately support the translation of this gene therapy approach into a human treatment. This will be of great significance to not only offer a potential life-saving treatment for patients with PDHA1 deficiency, but also providing broader proof- of-concept for AAV9fyhr as a CNS-targeting platform for other neurological disorders.

NIH Research Projects · FY 2026 · 2026-04

Project Summary/Abstract Chronic kidney disease (CKD) is a major public health challenge that plagues approximately 1 in 7 Americans, most of whom experience asymptomatic progressive CKD until the disease is at advanced stages, resulting in devastating complications, including kidney failure and death. Due to the symptomless characteristics of early stages of CKD, many individuals remain underdiagnosed and untreated. This especially impacts African Americans (AA) and Hispanic persons and those with lower socio-economic status (SES) as they often engage with health systems at later stages of CKD leading to worse outcomes. Thus, community level interventions are needed to identify and intervene sooner for those unaware of their risk (~90%). Additionally, dietary intake, a significant social driver of health, plays a considerable role in the prevention and management of CKD and cardiovascular complications, yet lower SES communities have less access to health-promoting foods and lower self-efficacy for eating healthy, worsening CKD outcomes. To fill these gaps, our team has established that base-producing fruits and vegetables (F&V) preserved kidney function and reduced cardiovascular disease (CVD) risk in health system-based cohorts. These findings were translated to a community-dwelling population in our recently completed R21 (R21DK113440) that evaluated the benefits of base-producing F&V among 142 AA adults identified with CKD through community-based health screens. We found that participants who received a culinary medicine cooking intervention plus base-producing F&V as compared to those receiving F&V alone had 31% lower urine albumin to creatinine ratio (UACR) after 6 months of the intervention. In this R01, we propose to extend our group’s foundational work by evaluating whether cooking instructions delivered through community-based culinary medicine in addition to provision of base-producing F&V (FV+Cook) promotes greater kidney, and additionally CVD, benefits than providing base- producing F&V alone (FV Only) in a larger, multi-ethnic sample. This will be evaluated through the following Specific Aims: (1) Determine whether UACR is reduced to a greater extent with the FV+Cook intervention as compared to FV Only at 6- and 12-months (primary), (2) Determine whether F&V+Cook compared to F&V Only improves secondary measures (i.e., blood pressure, body mass index, lipid levels, hemoglobin A1c) at 6- and 12-months, (3) Evaluate F&V consumption, dietary behaviors and quality (ASA-24, Veggie Meter®), and behavioral mediators (nutrition knowledge, self-efficacy, social support, cooking skills) at 6- and 12-months, and (4) Use RE-AIM domains (Reach, Effectiveness, Adoption, Implementation, and Maintenance) to evaluate implementation outcomes. In summary, this study can provide critical data to guide sustainable, scalable, and feasible clinical and public health practice on improving CKD outcomes in populations at risk for adverse long-term consequences, ushering a new era of food as medicine health interventions in community settings.

NIH Research Projects · FY 2026 · 2026-04

PROJECT SUMMARY Schistosomiasis, a neglected tropical disease caused by sexually dimorphic parasitic flatworms (schistosomes), is sustained in endemic regions of Sub-Saharan Africa and Southeast Asia by the egg-laying of mature females. Female sexual maturation and subsequent egg production depend on continuous pairing with male worms, highlighting the central role of schistosome reproductive biology in both disease pathology and life cycle maintenance; eggs can cause disease in human tissue or contaminate freshwater. Male schistosomes synthesize β-alanyl tryptamine (BATT), a recently discovered pheromone that induces female sex organ maturation and egg production. Contact with male worms or exogenous BATT treatment induces maturation, yet the precise signaling pathways activated by this pheromone remain largely unknown. This study aims to elucidate the molecular mechanisms by which the BATT pheromone triggers female sexual maturation. I hypothesize that BATT activates specific G protein-coupled receptors (GPCRs) and downstream signaling cascades, leading to changes in gene expression and cellular processes essential for oogenesis and vitellogenesis. BATT is an entirely new signaling molecule in flatworm biology and the mechanisms of signal reception by the female and subsequent downstream signaling that is triggered by BATT are unknown. To address this, I will employ a combination of transcriptomics, proteomics, and functional assays using Schistosoma mansoni as a model. The goal of this work is to uncover molecular (AIM 1) and cellular (AIM 2) targets of BATT. In AIM 1, I will use complementary genetic and chemical biological approaches to uncover molecular targets of BATT, including systematic screening of schistosome GPCRs and the development of activity-based probes. In AIM 2, I will use transcriptomic approaches to define BATT-responsive cell types, which will then be screened for relevant receptors to support AIM 1. This important work explores a major unknown in flatworm reproductive biology and aims to understand the molecular mechanisms underlying sexual maturation in schistosomes.

NIH Research Projects · FY 2026 · 2026-04

Project Summary Dr. Tamia Harris-Tryon is an Associate Professor in the Department of Dermatology at UT Southwestern Medical Center. She has established a successful and independent research program focused on elucidating mechanistically interactions between the immune system, the skin, and the microbes that colonize the skin surface. Her experiences as an active clinical dermatologist, basic science researcher, and mentor have positioned her to be an ideal candidate for the K24 Mentoring Career Development Award. Leveraging her basic science findings demonstrating that the immune system regulates androgen production in the skin and her passion for mentoring trainees and faculty, Dr. Harris-Tryon and her team developed a novel method to quantify skin hormones non-invasively at the skin surface and observed that the immune system regulates androgen production in skin cells (PNAS, 2021). Her unique observations and studies have moved the field forward and her research program has been supported by continuous funding from the NIH, first with a K08 and now with R01 funding. Her team is also sponsored by foundation support from the Dermatology Foundation and industry award. These works and support have paved the way for a translational research program focused on defining how androgen- antagonism could be leveraged as a therapeutic strategy for the treatment of inflammatory skin diseases. In this proposal, Dr. Harris-Tryon has designed a series of aims to apply translational patient-oriented research (POR) approaches to these research questions, therefore expanding her research program and advancing therapeutic approaches in dermatology. The K24 award will support Dr. Harris-Tryon’s scientific career activities by allowing her to engage in professional development via coursework/training and execution of novel projects that bolster her research program and support future independent funding by both Dr. Harris-Tryon and her mentees. In addition to supporting scientific career activities, the K24 award will directly allow Dr. Harris-Tryon to pursue mentorship/leadership training and enhance her ability to more deeply engage with specific mentees pursuing K and R01 awards and more broadly engage with all mentees in dermatology training. The overall scientific aims of this proposal are to: 1) Determine if elevations in androgen production in the affected skin of AD patients correlates with skin barrier dysfunction and disease severity and 2) Elucidate the influence of the FDA approved anti-androgen therapy, spironolactone, on skin androgen amounts and skin barrier function. Completion of these aims will elucidate how AR-signaling regulates phenotypes in the skin and provide a platform to bolster the ability of Dr. Harris-Tryon and her mentees to complete patient-oriented research. If our hypothesis is correct, androgens may represent a novel biomarker for AD. These experiments will also provide the scientific rationale for future trials testing the efficacy of anti-androgen therapies in the treatment of AD.

NIH Research Projects · FY 2026 · 2026-04

PROJECT SUMMARY In adults with descending thoracic aortic aneurysm (TAA), vascular repair (grafting) reduces the ~20% yearly rate of rupture and/or mortality but is associated with negative perioperative consequences. Currently, thoracic endovascular aortic repair (TEVAR) has become the standard treatment for descending TAA due its lower in and out of hospital morbidity and mortality. While repair is essential, there are known negative consequences of TEVAR related to the graft material’s stiffness. Notably, the non-physiological properties of the graft may attenuate the long-term benefit of TAA repair by reducing end-organ function. Indeed, age-related stiffening of the native aorta is known to increase arterial pressure, wave reflections and the associated adverse end-organ remodeling related to greater transmission of pressure and flow pulsatility in key pressure and flow sensitive organs, such as the heart, brain, and kidneys. Despite these well-known effects of native aortic stiffening, no study has comprehensively and directly assessed the hemodynamic consequences of descending TAA repair (i.e. stiffening) locally on the aorta or on the heart, brain and kidneys. It is known that placement of grafts in the ascending aorta elicits increased aortic flow velocity, local aortic stiffness, downstream descending aortic dilation, increased wall shear stress, and likely increases pressure and flow pulsatility, arterial wave reflections and aortic pressure that, together, elicit pathological vascular and end-organ remodeling associated with reductions in function and end-organ damage. Importantly, no study has performed high-resolution assessments of the hemodynamic (pressure, wave reflection and pulsatility) and end-organ consequences of descending TEVAR at rest, but also importantly not during exercise where the consequences of aortic grafting may be exaggerated. Thus, the overall aim of the K99/R00 proposal is to perform high-resolution phenotyping of the central hemodynamic consequences of TAA pre- and post-TEVAR at rest and during exercise and determine the magnitude of associated effects on end-organ structure and function. Our project will begin to fill the large unmet gap in understanding aortic and aortic aneurysmal physiology at rest and during exercise, the impact of the standard treatment for descending TAA, and point the way towards better recommendations in practice and for design of future therapies. Furthermore, these data will encourage medical device companies to design more compliant grafts so that the positive effects of aortic grafting in terms of reducing aortic rupture risk are not offset by inducing reductions in cardiac, brain and renal function. Completion of the proposed project will provide me with a unique skillset, different from that of my mentoring team, rendering me highly competitive for future NIH funding related to the study of hemodynamics and end-organ function in health and disease.

NIH Research Projects · FY 2026 · 2026-04

Genetic and Immunological Investigation of ABCF1 in Celiac Disease and Autoimmunity Abstract: Inborn Errors of Immunity are Mendelian disorders caused by rare pathogenic variants in genes with critical immunological functions. Clinically, they manifest as increased susceptibility to infections or autoimmune diseases. Celiac disease (CeD) is a chronic autoimmune disorder triggered by dietary gluten, characterized by increased epithelial lymphocytes and villous atrophy in the small intestine. Familial clustering occurs in approximately 10% of affected individuals, providing an opportunity to identify rare causative variants that contribute to immune dysregulation. In our pilot study, we enrolled 42 families with two or more CeD-affected members to identify potential disease-causing genes. Whole exome sequencing (WES) identified ABCF1 (ATP- binding cassette sub-family F member 1) as a strong candidate. ABCF1 is an essential cytosolic protein with pleiotropic functions, including E2 ubiquitin-conjugating activity and ribosomal regulation. Our preliminary data confirmed an association between rare ABCF1 variants and CeD, as well as inflammatory bowel disease, by integrating data from All of Us and UK Biobank. We demonstrated that peripheral blood mononuclear cells from individuals with a heterozygous loss-of-function ABCF1 mutation exhibit significantly increased baseline expression of interferon-stimulated genes (ISGs). Furthermore, ABCF1 regulates IFN-α induced STAT1 phosphorylation and interacts with key proteins such as RIG-I and TRIM25, which are involved in pathogen- associated molecular pattern (PAMP)-mediated innate immune responses. Additionally, using a conditional Abcf1-deficient mouse model, we observed increased susceptibility to dextran sodium sulfate (DSS)-induced colitis. To further characterize this novel genetic disorder, we will determine how ABCF1 regulates type I IFN production and responses, assess the pathogenicity and domain-specific impacts of naturally occurring ABCF1 mutations, and investigate how ABCF1 deficiency promotes the development of DSS-induced and Il-10⁻/⁻ colitis in Abcf1-deficient mice. These studies will elucidate novel molecular mechanisms underlying JAK-STAT activation and innate immune regulation, paving the way for precision treatments for CeD and other autoimmune diseases.

NIH Research Projects · FY 2026 · 2026-04

The development of innovative chemical reactions is critical to advancing drug discovery and improving human health. Our laboratory focuses on addressing unmet needs in basic biomedical research through the development of selective chemical methods that impact drug discovery in two transformative ways. Research Direction 1: Stereoselective synthesis of sp3-rich N-heterocycles via photocatalytic C–H annulation We propose to develop stereoselective catalytic reactions to synthesize chiral N-heterocycles, a class of sp³- rich scaffolds prevalent in FDA-approved drugs. Our strategy employs enantioselective photocatalytic C–H annulations mediated by dual photoredox and chiral Lewis acid catalysis to generate functionalized N- heterocycles with diverse substitution patterns and stereochemical complexity. This research direction will provide streamlined access to several classes of saturated heterocycles, including morpholines, piperidines, pyrrolidines, tetrahydroquinolines, and indolines. Insights gained from mechanistic studies will inform the development of highly stereoselective processes. Research Direction 2: Late-Stage Photochemical Installation of Photocrosslinkers into Drug-Like Molecules We propose to advance chemical biology by developing methods to directly functionalize drug-like molecules for mechanism-of-action studies. Specifically, we will design novel photoaffinity labeling (PAL) reagents to facilitate the late-stage installation of photocrosslinking groups into bioactive molecules. Leveraging photochemical Minisci reactions, this approach will enable the synthesis of novel PAL probes in one step from bioactive molecules through selective C–C bond formation. This innovation addresses a critical bottleneck in drug discovery, providing a generalizable platform for PAL probe development. We anticipate this research direction will accelerate the identification of molecular targets of drug-like molecules. This NIGMS MIRA proposal leverages robust preliminary data from our laboratory, including recent advances in photochemistry and stereoselective catalysis. We will incorporate mechanistic studies and collaborations in spectroscopy, computational chemistry, and chemical biology to refine and expand the scope of our methods. Guided by the mission of the NIGMS, we propose to develop broadly useful chemical methods with far-reaching implications in synthetic chemistry, chemical biology, and pharmaceutical research. By enabling the efficient synthesis of chiral N-heterocycles and facilitating the direct conversion of drug-like molecules into PAL probes, our research proposal will contribute to the advance of drug discovery and the understanding of biological processes, ultimately laying the foundation for the improved treatment of human disease.

NIH Research Projects · FY 2026 · 2026-04

Project Summary Arthropod-borne viruses or “arboviruses” are insect-transmitted viral pathogens that pose a significant threat to human and animal health worldwide. However, we still lack effective therapeutics to combat most arbovirus infections. A deeper understanding of the conserved innate immune mechanisms that restrict arbovirus replication in insect and mammalian hosts may reveal strategies for preventing or treating arboviral disease. Thus, we sought to develop an innovative, yet simplistic, approach to identify conserved antiviral host factors affecting arbovirus replication that, at the same time, inherently provides insight into virally-encoded strategies that evade these host defenses. Here, we propose to use a novel arbovirus "rescue" assay wherein candidate immune evasion proteins (IEPs) encoded by unrelated mammalian viruses can be transiently expressed in insect cells and assayed for their ability to sensitize insect cells to arbovirus infection. The rationale behind this approach is that mammalian virus-encoded IEPs that enhance arbovirus replication in insect cells likely do so because they happen to inhibit key antiviral factors/pathways that are conserved between insect and mammalian hosts. One can then use these IEPs as “tools” to identify and characterize the conserved immunity factors these IEPs target. Thus, this screening methodology provides a mechanism to both identify novel IEPs encoded by mammalian pathogens and the functionally-relevant components of the eukaryotic innate immune response these IEPs inhibit. To discover IEPs that promote arbovirus replication in insect cells, we will screen an expression library encoding 93 “viral ubiquitination modulators (VUMs)” derived from 33 different mammalian viruses. VUMs are virally-encoded proteins that inhibit, usurp, and/or re-direct the host ubiquitination system to promote viral replication. Given that ubiquitination is a key post-translational modification that alters the stability and/or function of cellular proteins, VUMs often hijack the ubiquitination system to inhibit or degrade host proteins that are critical for antiviral defense. We hypothesize that some VUMs may target cellular antiviral factors that are conserved between insect and mammalian hosts and that are critical for restricting arboviruses. Indeed, our initial screens identified VUMs from disparate mammalian viruses that enhance arbovirus replication in insect cells. These results, along with our prior successes in using this system to identify novel IEPs and conserved antiviral responses (Rex et al., 2024, Nat. Microbiol.; Embry et al., 2024, PLoS Pathog.), suggest that we can use VUMs as tools to both inhibit, and discover, conserved antiviral immunity factors. Our study will: 1) Identify VUMs encoded by mammalian viruses that promote arbovirus replication in insect cells; 2) Identify conserved insect and mammalian factors interacting with VUM “hits” from our arbovirus rescue assays; and 3) Identify the conserved host factors interacting with VUMs that normally block arbovirus replication. Our long-term goal is to use this system to define the critical eukaryotic innate immune mechanisms that restrict arbovirus replication.

NIH Research Projects · FY 2026 · 2026-04

Project Summary/Abstract Pyruvate, a key product of glycolysis, is transported into mitochondria to fuel the tricarboxylic acid (TCA) cycle, driving oxidative phosphorylation (OXPHOS) and ATP synthesis. The Mitochondrial Pyruvate Carrier (MPC) is crucial for this process, enabling the transport of pyruvate from the cytosol into the mitochondrial matrix. Due to its essential role, MPC dysfunction is associated with a range of diseases. In cancer, MPC disruption promotes the Warburg Effect, which favors aerobic glycolysis, and in turn encourages tumor growth, metastasis, and poor prognosis. Conversely, inhibiting MPC in the liver and muscle has shown therapeutic potential for type 2 diabetes (T2D) by enhancing glucose uptake, promoting fat oxidation, improving insulin sensitivity, and reducing gluconeogenesis. Additionally, neurodegenerative diseases often involve metabolic dysfunction linked to impaired mitochondrial energy metabolism, highlighting the therapeutic potential of targeting MPC to address these conditions. In humans, MPC is encoded by three homologous genes—MPC1, MPC1-like (MPC1L), and MPC2—and belongs to the recently identified triple-helix-bundle (THB) transporter family. MPC functions as a heterodimer, either MPC1–MPC2 or MPC1L–MPC2, with each protomer containing three transmembrane helices. Our long-term goal is to elucidate the transport mechanisms of MPC proteins and to develop targeted therapies for related diseases. In our preliminary studies, we engineered the human MPC1-2 complex (~25 kDa) and obtained a functional construct (~80 kDa) suitable for structural determination by cryogenic electron microscopy (cryo-EM). We resolved the structures of human MPC1–2 complex in the intermembrane space (IMS)-open and inhibitor-bound matrix-open states. Based on these findings, the objective of this proposal is to uncover the mechanisms underlying pyruvate transport, inhibition, and regulation of human MPC, and to develop its inhibitors for therapeutic purposes. Our projects aim to 1) Uncover the mechanism of pyruvate transport mediated by human MPC1-2 complex; 2) Elucidate the inhibitory mechanisms of existing inhibitors and develop novel modulators for human MPC1-2; 3) Extend the established approaches to investigate human MPC1L1 and MPC proteins in other species. Successful completion of this research will provide critical insights into pyruvate transport, a process fundamental to cellular metabolism, and establish a foundation for therapeutic strategies targeting MPC in diseases such as neurodegenerative disorders, cancer, and diabetes.

NIH Research Projects · FY 2026 · 2026-04

Project Summary/Abstract Naturally occurring heavy metals in our environment can be harmful to human health. For instance, arsenic, cadmium, chromium, and nickel are classified as Group 1 carcinogens by the International Agency for Research on Cancer. Post-transcriptional gene regulation—through RNA modifications or regulatory RNAs—is a major mechanism by which cells reprogram gene expression. Our objective is to determine how heavy metals impact RNA modifications and the processing of regulatory RNAs. In Aim 1, we will assess the effects that heavy metals may have on a key mRNA methyltransferase, METTL3-METTL14, evaluating both its enzymatic efficiency and specificity. We will also investigate how a heavy metal influences m6A in the transcriptome and how RNA modification events are linked to changes in chromatin and DNA methylation. In Aim 2, we will evaluate the effects of heavy metals on an oncogenic tRNA methyltransferase, METTL1. We will analyze variations in its activity and specificity with different metals and will also explore any crosstalk between METTL1 activity and other tRNA modifications, along with AKT signaling that phosphorylates METTL1. In Aim 3, we will study the effects of heavy metals on microRNA biogenesis. The Drosha-DGCR8 complex depends on multiple metals to initiate microRNA processing. We will examine the mechanisms that underlie metal-induced dysregulation of microRNA processing. Additionally, we will analyze how heavy metals affect the crosstalk between RNA methylation and processing. In summary, our work will leverage the latest insights into the molecular mechanisms of catalysis and substrate specificity of RNA modification and processing enzymes to provide new information on how heavy metal toxins interact with our epitranscriptome to induce pathogenesis.

NIH Research Projects · FY 2026 · 2026-04

PROJECT SUMMARY Recent studies with ‘dirty’ or microbially experienced mice suggest that one crucial difference between mouse models and humans is the history of infection and microbial exposure. Laboratory mice lack the diversity of microbial exposure experienced by their wild mice counterparts and humans. When SPF mice are exposed to microbes found in wild mice their immune responses change and start to more closely mimic the human immune response, indicating that infections are important for maturing the immune response. Because exposing laboratory mice to wild mice is not feasible for many researchers, new mouse models are needed to bridge the gap between mouse and human immune research. We developed a model of sequential infection, where mice are infected with a series of three viruses and an intestinal parasite starting early in life. We showed that mice with sequential infections have different response to vaccination and have blood transcriptional signatures that more closely mimic wild mice and humans. Therefore, we hypothesize that exposure of laboratory mice to a defined and small number of viral and parasitic infections will be sufficient to recapitulate many aspects of other dirty mouse models. We propose to determine which aspects of the immune response of mice exposed to wild mice are recapitulated by our sequential infected mice. We will also determine the contribution of specific pathogens to the alterations in the mouse immune response and test whether the order of infections changes the outcome of the sequential infection model. The conclusion of these experiments will be a well-defined and simple microbial-experienced model that can be reproduced by other investigators. In addition, we will have defined the contribution of specific mouse pathogens to immune system maturity. These experiments will enhance the translatability of mouse models to human preclinical research.

NIH Research Projects · FY 2026 · 2026-03

PROJECT SUMMARY Despite being an established RCT-supported therapy, the adoption of deep brain stimulation (DBS) for Parkinson’s disease (PD) remains relatively low. While partly due to being a surgical therapy, adoption is further hindered by limited clinical benefit, off-target side-effects, and the burden of generator replacement surgery or battery charging. These limitations are at least in part attributable to the use of relatively simplistic fixed high- frequency stimulation. Recent optogenetic and computational modeling work has shown that finely tuned intermittent burst-patterned pallidal DBS can differentially modulate specific cell types and produce motor benefits that endure beyond stimulation cessation. Our team’s pilot study in people with Parkinson's disease (PwPD) comparing conventional and burst-DBS in globus pallidus internus (GPi) showed equal efficacy and tolerability, motivating further investigation. A mechanistic understanding of the physiological underpinning of therapeutic benefits of burst-DBS is critical to optimizing and ultimately facilitating translation of pallial burst DBS for PwPD, thereby addressing the limitations of fixed high-frequency DBS. While early results are encouraging, questions remain about the relevance and optimal location and burst-DBS frequency for long-lasting benefits in the human basal-ganglia-thalamo-cortical (BGTC) motor network. We will utilize our team’s expertise in intracranial physiology and PD to analyze BGTC circuits through recordings of single-neuron and evoked potential dynamics, local field potentials (LFP), electrocorticography, and network physiology. We focus on the GPi because its main sources of input are the two basal ganglia structures implicated in preclinical work (striatum and globus pallidus externus), both of which are underactive in circuit theories of PD. We address our hypothesis through 3 aims. AIM 1: Identify the optimal location and frequency for GPi burst-DBS through functional circuit mapping: We will define human-specific settings and location for producing the most potent antiparkinsonian modulations of BGTC neurophysiological PD readouts in response to intraoperative burst-DBS. AIM 2: Validate LTP effects of the optimized burst-DBS paradigm and derive brain-behaviour relationships: We will critically assess spatiotemporal neural features to demonstrate that burst DBS produces beneficial forms of LTP in the BGTC circuit, and to provide proof-of-principle of sustained benefit on a short timescale in response to intraoperative burst-DBS. AIM 3: Demonstrate subacute neural corelates of personalized burst-DBS benefit & relapse dynamics: We will leverage sensing-enabled DBS devices to evaluate acute (during burst-DBS) and enduring (beyond stimulation cessation) antiparkinsonian therapeutic effects and neurophysiology of personalized burst-DBS in the outpatient setting, in order to determine whether LFP and/or cortical recordings can be used as functional proxies to track enduring motor benefits and as biomarkers for closed-loop burst-DBS. Our work has the potential to improve therapy by providing a biological foundation for future large scale clinical trials assessing long-term outcomes of optimized GPi burst-DBS.

NIH Research Projects · FY 2026 · 2026-03

PROJECT SUMMARY Lipid Droplets (LDs) are rapidly emerging as critical adaptive organelles at the nexus of lipid metabolism and human disease. The 10th FASEB Summer Research Conference on "Lipid Droplets" will delve into this rapidly evolving field. As the primary cellular lipid storage organelles, LDs serve as vital hubs of lipid metabolism, influencing energy storage, lipid signaling, membrane biogenesis, and lipotoxicity. Pathological LD accumulation is a hallmark of metabolic diseases including obesity, insulin resistance, diabetes, fatty liver disease, lipodystrophy, cancers, cardiovascular diseases, and neurodegeneration. The growing prevalence of metabolic disorders in the United States underscores urgency to mechanistically understand the molecular underpinnings of LD formation, growth, movement, and turnover. Understanding LD biology promises novel therapeutics and is thus of high interest to scientists in academic, pharmaceutical, and biotechnology sectors. This conference will take place from July 26 to 30, 2026, in Scottsdale, AZ, USA. It will co-locate with the FASEB SRC Phospholipids conference, and include three keynote addresses from lipid metabolism leaders: Dr. Hugo Bellen (Baylor College of Medicine, HHMI), Dr. Elina Ikonen (University of Helsinki), and Dr. Bruno Anthonny (CNRS). As the longest-running meeting solely focused on LD biology, it will feature a multi- disciplinary speaker line-up focused on leading-edge research in basic and clinical science. The conference format comprises eight sessions featuring talks by invited speakers, 15 short talks selected from submitted abstracts, two poster sessions (together with the FASEB SRC Phospholipid conference), a Career-Oriented Workshop, and Meet-the-Experts sessions. Its trainee-focused environment has been carefully crafted to foster interactions between trainees, early career investigators, and established researchers. Scientific sessions will span the entire spectrum of LD biology. Distinguished researchers will deliver talks spanning many approaches (biophysics, genetics, biochemistry, cell biology, physiology) and cutting-edge technologies (chemical biology tools, lipidomics, new imaging approaches) in a range of model systems (cultured cells, Drosophila, yeast, C. elegans, mice, humans). A primary aim of this conference is to nurture and empower the next generation of scientists. To that end, we seek funding to support the participation of 15 graduate students, postdoctoral fellows, and early career investigators. The conference's informal and trainee-oriented setting will provide numerous opportunities for planned and spontaneous informal interactions, affording young investigators the chance to present their work, obtain valuable feedback from leaders in the field, and receive career guidance. In closing, this conference stands as the pioneering international gathering dedicated exclusively to lipid droplet biology and its profound relevance to human diseases. It continues to serve as a unique and memorable forum for researchers to exchange ideas and share groundbreaking results.

NIH Research Projects · FY 2026 · 2026-03

Project Summary: Rett Syndrome (RTT) is a progressive neurological disorder characterized by severe cognitive and motor impairments caused primarily by mutations in MECP2. The molecular mechanisms by which disruption of MECP2 gives rise to RTT remain unclear. MECP2 is known to bind to methylated DNA in the brain, regulating the expression of neuronal genes. However, previous studies have shown complex patterns of gene dysregulation in RTT that challenge this model, such that only a subset of genes appear to be regulated by MECP2 binding to DNA methylation. We recently discovered that MECP2 preferentially binds to specific gene enhancers that we named MECP2-Binding Hotspots (MBHs). Surprisingly, MECP2 binds to these MBHs independently of DNA methylation, contrasting with its well-established role in binding methylated DNA. At MBHs, MECP2 appears to act as a repressor of enhancer activity. Importantly, over 60% of genes derepressed upon MECP2 deletion are associated with MBHs, suggesting that MBHs might be a major mechanism by which MECP2 controls genes. Preliminary analyses indicate that MBHs, but not MECP2 bound to methylated sites across the genome, are bound by histone deacetylase-containing nuclear receptor co- repressor (NCOR) complex, suggesting that MBHs may repress enhancer activity by recruiting the NCOR complex to enhancers. Taken together, our findings indicate a previously uncharacterized mechanism of transcriptional regulation by MECP2. Moreover, these results implicate dysregulation of specific enhancers as a possible mechanism underlying RTT. To gain insights into how MECP2 regulates genes and how dysregulation of MECP2 leads to RTT, we propose to (1) define the interaction between MECP2 and MBHs, and (2) elucidate the molecular mechanisms by which MBHs repress enhancers. This work has significant implications for understanding the molecular basis of MECP2 function and the complex gene dysregulation observed in RTT and will uncover new therapeutic targets and strategies for treating RTT.

NIH Research Projects · FY 2026 · 2026-03

PROJECT SUMMARY Both metabolic dysfunction-associated steatotic disease (MASLD) and atherosclerosis are caused by dysregulation of lipid metabolism, with apolipoprotein B (ApoB) pivotal in both very low-density lipoprotein (VLDL) secretion and LDL receptor-mediated endocytosis. ApoB-containing VLDL, produced and secreted by the liver, carries lipids to peripheral tissues and becomes cholesterol-rich LDL, contributing to atherosclerosis development. Genetic variation influences hepatosteatosis and VLDL/LDL levels in humans and mice under specific environmental conditions. To identify genes influencing this process, we employed unbiased forward genetic screening and highly automated meiotic mapping to identify mutations that modify MASLD and lipid metabolism in mice sensitized by a high-fat diet (HFD). A rare dominant missense allele of helicase with zinc finger 2 (Helz2), named Colby, was detected in this screen. Unlike most MASLD mutants that are closely associated with obesity, our preliminary data indicate that Helz2 mutant Colby mice exhibited significant hepatic lipid accumulation without a concomitant increase in body weight when fed an HFD. Knockout of Helz2 increased hepatic lipid secretion, whereas the Colby mutation dramatically reduced it, suggesting hepatocyte-intrinsic regulation of VLDL secretion by HELZ2. Highly expressed in the liver, HELZ2 specifically targets Apob mRNA for degradation through direct binding. The Colby mutation increases the nuclease activity of both mouse and human HELZ2, reducing Apob levels. These results led to our central hypothesis that HELZ2 is critical for regulating hepatic lipid secretion by limiting the mRNA levels of Apob. To test this hypothesis, we propose three Specific Aims. Aim 1 will identify the mechanism of MASLD development in Helz2 mutant mice and its potential therapeutic application in treating atherosclerosis. Aim 2 will determine HELZ2’s role in ApoB regulation. Aim 3 will test human APOB regulation by human HELZ2 and study human HELZ2 mutations. The MASLD phenotype caused by Helz2 mutation differs fundamentally from classic obesity-associated MASLD mouse models. Our study reveals a new level of ApoB regulation on mRNA stability, differing from other ApoB-related research focusing on ApoB degradation pathways during VLDL maturation. Completion of this work may suggest new therapeutic approaches to treat MASLD and atherosclerosis by targeting Apob mRNA.

NIH Research Projects · FY 2026 · 2026-02

Tachycardia, or abnormally fast heart rate, is an important risk factor for cardiovascular morbidity and mortality. Prolonged tachycardia is known to induce cardiomyopathy in patients who have no prior structural heart diseases. Moreover, transient tachycardia, frequently observed in heart failure patients, can exacerbate the cardiovascular outcome. However, very little is known about the molecular drivers underlying tachycardia-induced cardiac dysfunction. This gap in our knowledge hinders the development of more effective heart failure treatment, especially for patients with hard-to-control tachycardia. This K99/R00 proposal will leverage recent advances in induced pluripotent stem cell (iPSC), tissue engineering, and multiomics technologies to uncover the molecular signaling pathways critically involved in the pathology of tachycardia-related heart disease. The applicant, Dr. Chengyi Tu, has established and validated an in vitro tachycardia platform using engineered heart tissue (EHT). In Aim 1, Dr. Tu will perform metabolomic and transcriptomic profiling of EHTs with or without tachypacing. To validate the physiological relevance of the EHT model, canine samples from tachypacing-induced heart failure will also be profiled. Preliminary data from the EHTs and the canine samples coherently indicate that the disruption of glycolysis homeostasis may underly the impairment of cardiac function by tachycardia. Metabolomics analysis shows that tachypacing in EHTs resulted in a selective accumulation of glycolysis intermediates such as glyceraldehyde 3-phosphate (GA3P) and 3-phosphoglycerate (3PG). Interestingly, promotion of fatty acid metabolism accelerated the recovery of cardiac contractility in tachypaced EHTs. Based on these novel results, Aim 2 will focus on elucidating how different glycolysis intermediate metabolites affect the function of cardiomyocytes, which has yet to be systematically examined. Lastly, Aim 3 (R00 phase) will employ state-of-the-art mass spectrometry workflow to screen for novel binding targets of glycolysis intermediates in cardiac cells, and examine the potential therapeutic benefits of manipulating these targets. This K99/R00 proposal will be guided by an excellent mentoring team with diverse expertise, including mentor Dr. Joseph Wu (iPSCs and cardiac biology), co-mentor Dr. Sanjiv Narayan (arrhythmia), advisors Dr. Michael Snyder (genetics and multi-omics), Dr. Yuqin Dai (metabolomics), Dr. Stanley Qi (CRISPR interference) and Dr. Beth Pruitt (bioengineering), as well as collaborators Dr. Fabio Recchia (canine model) and Dr. Donald Bers (cardiac physiology). To sum up, the completion of the proposed study will significantly advance our mechanistic understanding of how tachycardia adversely affects the heart, thereby creating new opportunities for therapeutic interventions. The proposed training will significantly strengthen and expand Dr. Tu’s research expertise, providing substantial momentum to his transition toward an independent cardiovascular researcher.

NIH Research Projects · FY 2026 · 2026-02

PROJECT SUMMARY/ABSTRACT Charcot–Marie–Tooth (CMT) neuropathies are a genetically and phenotypically heterogeneous group of disorders caused by pathogenic variants in over 100 different genes. Ganglioside-induced differentiation- associated protein 1 (GDAP1) gene mutations cause various forms of CMT including CMT4A and CMT2K. CMT4A is a severe, early onset neuropathy caused by autosomal recessive, loss of function mutations, while CMT2K is a milder, late onset neuropathy caused by autosomal dominant, gain of function mutations in the GDAP1 gene. Despite the clinical burden and the known GDAP1 cause in CMT4A and CMT2K, the potential of gene replacement therapy (GRT) for these patients remains unexplored. We propose to use an AAV9 vector to carry the GDAP1 gene to the spinal cord neurons and Schwann cells of newly characterized Gdap1 KO and KI rat lines and then to characterize the dose-responsive safety and efficacy of the AAV9/GDAP1 vector. Our central hypothesis is that AAV9-mediated GDAP1 GRT during early development will restore proper protein function and, therefore, ameliorate disease phenotypes in the newly characterized Gdap1 KO and KI rat models. We will test this hypothesis by pursuing two specific aims: Aim 1. Determine the safety and efficacy of AAV9/GDAP1 treatment in the Gdap1 KO rat model of CMT4A. Gdap1 KO rats will be dosed IT with the AAV9/GDAP1 vector at 2.5 or 12 months of age to mimic pre- and post-symptomatic intervention, respectively. A subset of rats treated at 2.5 months old will be euthanized at 1 month post injection to serve as the short-term study to evaluate transgene expression and safety of AAV9/GDAP1 (Aim1A). The remaining rats will be kept as the long-term study to evaluate the safety and efficacy of AAV9/GDAP1 (Aim1B). To evaluate safety, we will closely monitor all treated rats for signs of toxicity through comprehensive assessments. To evaluate efficacy, we will focus on longitudinal in-life behavioral and NCV tests, as well as postmortem histopathological changes on peripheral nerves. Aim 2: Determine the safety and efficacy of AAV9/GDAP1 treatment in the Gdap1 KI rat model of CMT2K. A key scientific question remains if our transgene expression can sufficiently outcompete the dominant- negative GDAP1 allele in the Gdap1R120W heterozygous KI CMT2K model to achieve a significant therapeutic rescue. Some studies have demonstrated the success of using GRT to rescue autosomal dominant mutations. Thus, Aim 2 is designed to evaluate this possibility. Our study will be carried out exactly as described in Aim 1 except in the Gdap1R120W KI rats. If these proof-of-concept studies in Aim 1 and 2 demonstrate favorable efficacy and an absence of toxicity, the data generated will serve as pivotal IND-enabling efficacy evidence, as well as supporting safety evidence. We will leverage our extensive experience to design and carry out the remaining IND-enabling studies. If successful, these efforts are designed to ultimately support the translation of this gene therapy approach into a first-in-human clinical trial. This will be of great significance not only to solve the unmet need for both CMT4A and CMT2K, but also providing a general proof-of-concept for other forms of CMT.

NIH Research Projects · FY 2026 · 2026-02

Project Summary Pathogenic bacteria have developed an array of strategies to undermine the host's defense mechanisms. In the context of non-Typhoidal Salmonella Typhimurium, a notable strategy involves the confinement of a single bacterium within a host vacuole called the Salmonella Containing Vacuole (SCV). This approach potentially provides an evolutionary advantage: by ensuring one bacterium per SCV, the host must target each SCV individually to eliminate the bacterial load, as opposed to confronting a vacuole harboring multiple bacteria clustered together. This mechanism could potentially extend the time required to combat the infection. Moreover, a single bacterium residing within an SCV exploits all accessible nutrients for replication and division. Conversely, multiple bacteria clustered within a single vacuole may engage in nutrient competition. Hence, understanding the fundamental mechanism of bacterial division in conjunction with vacuolar scission is imperative for gaining deeper insights into the pathogenic strategies employed by Salmonella enterica. Prior to this proposal we engineered a series of genetically minimal pathogenic strains that eliminates redundancy within the complex SPI-2 effector gene repertoire of Salmonella enterica serovar Typhimurium. Using this unique resource, here we will determine how a small network of SPI-2 T3SS effector proteins coordinate the complex events involved in SCV membrane scission and bacterial division within the host cell. This includes determining the location and host substrates of effector proteins at the SCV membrane using single cell particle tracking and live cell imaging (Aim 1). We will also investigate the molecular mechanisms of individual effector proteins that target a novel Rab-family GTPase defense system of the host (Aim 2). The resulting cellular and biochemical theories will be tested in murine models of systemic disease that are designed to evaluate effector protein functions at single cell resolution (Aim 3). Developing new drugs that target bacterial effector – host enzyme complexes would be an innovative approach to combat emerging infectious disease. While this idea holds great potential, the paucity of mechanistic information gleaned from deep studies into virulence factor functions has so far hampered their development as suitable drug targets. As a means to this end, the work performed here will allow us to predict new mechanisms of action for understudied Salmonella effector proteins and provide a glimpse into the structural-based evolutionary progression of a related pathogen groups.

NIH Research Projects · FY 2026 · 2026-02

PROJECT SUMMARY Although HIV-1 infection can be controlled through long-term treatment with anti-retroviral therapy (ART), a true cure has been elusive. Reservoir cells persist over time and support latent HIV-1 reactivation upon therapy cessation, yet little is known about the underlying molecular mechanisms. Our lab has recently identified previously unknown facets in the HIV-1 transcriptional program that we will explore in this proposal to help fill this knowledge gap, and may offer key insights into HIV-1 biology as well as cure strategies. The major goal of this grant application is to understand the role of transcription factors (TFs) in reservoir cells and Tat in first igniting and then sustaining the HIV-1 transcription reactivation program. We will accomplish this goal by leveraging genetic and genomic approaches to explore HIV-1 transcription at high-resolution in several immortalized cell models of latency and then cross-validate the data in samples from HIV-1 infected participants. Our recent studies have revealed that HIV-1 transcription reactivation proceeds through a previously unknown two-step mechanism: first ignited by transcription initiation through de novo Pol II recruitment (host phase) and later sustained by synchronization of pause release with re-initiation (viral phase). These two steps are the major transcriptional bottlenecks in the HIV-1 transcriptional program for a functional cure. Overcoming these bottlenecks guarantees a transcriptional switch that facilitates efficient latency reactivation. We will focus on defining the molecular mechanisms supporting HIV-1 transcription reactivation throughout the multi-phase HIV-1 transcription program. Specifically, we will explore the unifying central hypothesis that the composition and density of TFs at the proviral genome dictates the initial wave of HIV-1 transcription reactivation directly influencing Tat function and reactivation potential. We will examine the roles of the integration site, ligands stimulating reservoir cells and the interplay between TFs and chromatin accessibility. These goals are reflected in two Specific Aims: to define the relevance of TFs in reservoir cells that initiate and sustain HIV-1 reactivation (Aim 1), and to explore the interplay between TFs and chromatin accessibility during the transcriptional switch that facilitates efficient latency reactivation (Aim 2). If successful, this project will yield a better understanding of the molecular mechanisms by which TFs in reservoir cells and Tat converge to promote efficient HIV-1 transcription and latency reactivation, collectively having a sustained impact in the field. In keeping with NIAID’s mission of ending the HIV-1 epidemic, our long-term objective is to force the basic discoveries to devise alternative cure strategies. Thus, the fundamental knowledge to be gained could be used in future studies beyond the scope of this study, to exploit the transcriptional bottlenecks for functional cure approaches.

NIH Research Projects · FY 2026 · 2026-02

The oligoadenylate synthetase (OAS) is a family of enzymes that act as RNA sensors in innate immunity. Microbial dsRNA activates OAS synthesis of short linear 2’5’ oligoadenylates, which activate endoribonuclease RNase L, leading to IFN-I signaling and cell death. The antiviral function of the OAS-RNase L pathway has been established decades ago. However, the function of this pathway in bacterial infection and gut tissue homeostasis are poorly understood. The OAS-RNase L pathway genes are highly expressed in intestinal tissues especially epithelial cells in humans and mice. We found that OAS genes are induced in colon biopsies of active ulcerative colitis patients compared to healthy controls. In addition, several de novo heterozygous OAS1 gain-of-function variants are associated with early-onset inflammatory bowel disease in humans. We generated an Oas1a gain- of-function mouse model, which also develop intestinal inflammation that recapitulates the human disease. Therefore, we hypothesize that OAS enzymes are key innate immune sensors of microbial RNA in the intestine to maintain homeostasis, and aberrant activation of the OAS-RNase L pathway leads to IFN-I signaling and cell death resulting in intestinal inflammatory disease. Aim 1 will determine the expression and activity of the OAS pathway in bacteria-infected intestinal epithelial cells, mouse colitis tissue and human colitis biopsy. Aim 2 will characterize the Oas1a gain-of-function mouse intestinal disease. Together, this R21 proposal serves as a significant first step in filling a critical knowledge gap of OAS function in intestinal immunity.

NIH Research Projects · FY 2026 · 2026-02

PROJECT SUMMARY Pancreatic ductal adenocarcinoma (PDAC) is one of the most chemorefractory cancers among solid tumors. Even with the most effective chemotherapy (i.e., FOLFIRINOX), only 30% of PDAC patients respond. Therefore, identifying novel therapies is an urgent and unmet need in the PDAC field. One of the emerging strategies for treating these patients is targeting tumor architecture. The rationale of these therapies is to target tissue-specific properties, either in the stroma or in the tumor compartment, to disrupt tumor tissue homeostasis during disease progression or in response to treatment (chemotherapies). The majority of the previous studies have focused on targeting the stroma compartment (cellular or extracellular matrix portion), leaving the tumor compartment (e.g., tumor tissue-specific properties) a relatively unexplored territory. The goal of this proposal is to fill this knowledge gap by identifying tissue-specific properties in the tumor compartment to impair disease progression and to overcome PDAC chemoresistance. The rationale and feasibility of our proposed research studies are supported by our recent published work (Ligorio et al., Cell, 2019), in which we showed the existence of 8 different types of tumor glands, based on their internal composition of cells, with distinct proliferation (PRO) and metastatic (EMT) capabilities. Moreover, we found that tumor glands can be considered discrete functional “units” with distinct levels of aggressiveness and different chemorefractory behaviors. Therefore, our overarching hypothesis is that tissue-specific properties exist that govern tumor architecture by regulating the formation, internal structure, and evolution of tumor glands during disease progression and under treatment. To test this central hypothesis, we have recently developed (i) a method that allows us to characterize the cell identity (i.e., different PRO and EMT phenotypes) while preserving architectural information within human tissue, and (ii) an ad hoc mouse model to study tumor gland-forming ability using a time-course in vivo imaging technique (i.e., two-photon microscopy). By integrating these two methodologies, we (a) will clarify the functional behavior of tumor glands as a consequence of their internal structure (AIM.1), (b) will target an aggressive subpopulation of cancer cells to impair tissue homeostasis (AIM.2), and (c) will define the role of tumor architecture in PDAC chemoresistance and as a potential novel biomarker to predict the response to FOLFIRINOX chemotherapy (AIM.3). The proposed study will uncover new mechanisms (i.e., tumor tissue-specific properties) that drive tumor progression and PDAC chemoresistance with the ultimate intent (i) to find novel therapeutic avenues for PDAC patients, (ii) to define the role of tumor architecture in PDAC chemoresistance, and (iii) discover new FOLFIRINOX-predictive biomarkers to improve the dismal prognosis of PDAC patients.

NIH Research Projects · FY 2026 · 2026-02

Project Summary Alzheimer’s disease (AD) is the most common type of dementia and causes progressive memory loss. AD is a major challenge for our society since increasing numbers of individuals are affected. Currently, there are no treatments that can stop or reverse the disease. AD leads to buildup of toxic clumps of two proteins in the brain: Amyloid-beta (Aβ), which forms plaques, and tau, which forms tangles. Prior research shows that tau tangles are more directly responsible for worsening symptoms and disease progression than Aβ. Tau spreads by being released from one cell and taken up (“tau uptake”) by a neighboring cell. Blocking tau uptake could potentially stop the disease from progressing. One key player of tau uptake is a group of molecules on the surface of cells called heparan sulfate proteoglycans (HSPGs). HSPGs consist of core proteins and side chains of sugars called heparan sulfate (HS). Our prior research showed that a specific HS length and pattern of sulfate groups (“size and sulfation code”) is required for binding to tau. However, there are still major gaps in our understanding of how HSPGs drive tau uptake: 1.) We do not know if the HS size and sulfation code applies to neurons and microglia, two cell types in the brain that are mainly affected in AD. 2.) We do not know which specific HSPG core proteins are involved in tau uptake. 3.) We have not tested the role of HSPGs in mouse models. Our work also showed that an enzyme called NDST1, which is involved in making HSPGs, plays a crucial role in tau uptake. Reducing the activity of NDST1 in cells changes the sulfation pattern of HSPGs and substantially lowers tau uptake. Studies in mice show that reducing NDST1 activity is non-toxic. This makes NDST1 a potential target for new treatments to block tau spread. In this study, we propose two main goals: Goal 1: Identify the specific HS size and sulfation code and the HSPG core proteins involved in tau uptake in human neurons and microglia. We will use advanced tools (pharmacological tools, CRISPR interference, sugar photocrosslinking, mass spectrometry) to determine which components of HSPGs are key for tau binding and how they differ between neurons and microglia. Goal 2: Test how HSPGs contribute to tau uptake and spread in a mouse model. We will use genetically modified mice to reduce NDST1 activity specifically in neurons or microglia and measure how this affects tau buildup and disease progression. This research will enhance our understanding how HSPGs control cellular tau uptake and spread in the brain. The results could lead to new treatments that block tau spread, thereby slowing or stopping the progression of AD and related conditions.