University Of California Los Angeles

NIH Research Projects · FY 2024 · 2024-04

Project Summary Cerebral microvascular disease (CMD) causes white matter injury and is a major contributor of the vascular contributions to cognitive impairment and dementia (VCID), including as the most common co-morbidity to clinical Alzheimer’s Disease. Chronic vascular risk factors such as obesity accelerate the progression of CMD by primarily damaging brain endothelial cells. Risk factor-induced changes in cerebral endothelial cells contribute to an increased risk of dementia. The molecular changes in cerebral endothelial cells caused by chronic cerebrovascular risk factors remain unknown yet are critical to designing therapies to prevent and repair ischemic white matter lesions thereby lessening the burden of VCID. We propose that a central mechanism of CMD progression is dysregulated signaling in brain endothelial cells damaged by chronic vascular risk factors. Using endothelial cell-specific transcriptional profiling, we show that chronic endothelial injury resulting from obesity results in abnormal vascular expression of an interleukin/chemokine signaling pathway. This molecular pathway results in dysregulated vascular-oligodendrocyte progenitor cell (OPC) signaling. OPCs are a critical progenitor cell population in brain white matter that respond to injury and are responsible for remyelination. Preliminary data demonstrate that chronically injured endothelial cells up-regulate IL-17 receptor b (IL-17Rb) and its effector chemokine CXCL5. Though many inflammatory pathways may play a role in brain ischemia, we show that this is the major inflammatory pathway that is active in endothelial cells injured by this chronic vascular risk factor. Critically, we further demonstrate that endothelial expression of CXCL5 results in the chemotaxis of OPCs to the vasculature, limiting their ability to remyelinate after a focal white matter ischemic lesion. Using gain and loss of function studies at the in vitro, in vivo, and functional levels after stroke, we will dissect the molecular pathways involved in dysregulated vascular-OPC signaling and identify a role for chemokine signaling in regulating white matter injury underlying VCID. Studies in Aim 1 will use an in vitro conditioned medium paradigm to identify the precise signaling mechanisms in endothelial cells that promote CXCL5 expression while identifying the necessary receptors on OPCs that regulate migration and differentiation. In Aim 2, we will broadly determine the role of chemokine receptor activation on the ability of OPCs to differentiate and remyelinate after stroke using CXCR2 knockout and small molecule antagonism. Finally, we will show in Aim 3 that blocking the expression of CXCL5 in white matter endothelia can reduce cognitive and motor impairment associated with focal white matter stroke by promoting remyelination within the peri-infarct tissue adjacent to stroke. Together, these studies establish new molecular mechanisms for the vascular regulation of remyelination as critical to the pathogenesis of CMD and establish a new therapeutic target for VCID.

NIH Research Projects · FY 2026 · 2024-04

ABSTRACT Iron metabolism is an essential biological pathway that broadly impacts cellular processes ranging from aerobic respiration and nucleic acid metabolism to oxygen transport and multiple biosynthetic pathways (amino acid, nucleotide, and lipid). To maintain sufficient iron to perform these key cellular functions while avoiding the toxicity associated with excess iron, eukaryotic cells have developed an intricate set of regulatory pathways that coordinate iron utilization, transport, and storage and ensure that cellular iron levels are kept under tight physiological control. My laboratory has established a multi-faceted research program that utilizes a combination of biochemistry and proteomic mass spectrometry-based methods to explore the regulatory mechanisms underlying iron metabolism. We are currently focused in two areas. First, we are characterizing the E3 ubiquitin ligase FBXL5 and examining the hypothesis that it functions as a key signaling hub responsible for integrating a diverse set of iron-regulated signaling cues in order to coordinate multiple iron homeostatic pathways. Second, we are actively developing novel proteomic mass spectrometric methods to address key outstanding questions in iron metabolism and other biological processes. Investigation into these areas will not only uncover novel features regulating iron metabolism but also contribute to our understanding of how dysregulation of these pathways contributes to human disease.

NIH Research Projects · FY 2025 · 2024-04

PROJECT SUMMARY NK cells are required for antiviral immunity against viral infection in mice and humans. Patients with NK cell deficiencies display increased susceptibility to infection from human cytomegalovirus (HCMV), varicella zoster virus, and other herpesviruses. During the response to viral infection, activated NK cells expand, produce inflammatory cytokines such as interferon-γ (IFN-γ), and directly kill virally infected host cells. Potent induction of these effector functions is tightly linked to metabolic reprogramming, as NK cells undergo drastic metabolic changes to optimize energy production. Recent studies have identified the mammalian target of rapamycin complex 1 (mTORc1) and the sterol regulatory element-binding protein (SREBP) family of transcription factors as being key regulators of activated NK cell metabolism. Despite the importance of these metabolic adaptations, however, the precise molecular regulators linking extracellular activating signals to these intracellular metabolic mediators remain poorly understood. Our results indicate that the transcription factor myocyte enhancing factor 2C (MEF2C) is a central regulator of mature human NK cell proliferation, IFN-γ production, and cytotoxicity. CRISPR-Cas9 ribonucleoprotein (RNP)-mediated knockout of MEF2C resulted in impaired human NK cell effector function in vitro. Likewise, MEF2C loss resulted in impaired expansion of mouse NK cells during mouse cytomegalovirus (MCMV) infection in vivo. Metabolic analyses revealed that MEF2C promotes glycolysis, oxidative phosphorylation, and lipid uptake and accumulation in cytokine-activated human NK cells. MEF2C expression was induced by IL-2 and IL-15 stimulation in a phosphoinositol-3-kinase (PI3K)-dependent manner, while Cleavage Under Targets & Tagmentation (CUT&Tag) analysis indicated that MEF2C binds at the SREBF1 locus encoding SREBP1 to increase transcript expression. These results suggest that MEF2C is required for cytokine-activated NK cell proliferation, effector function, and metabolism through regulation of SREBP1. Thus, we propose studies to test the hypothesis that MEF2C activates SREBP1 to increase lipid synthesis and import after IL-2/15 activation to fuel NK cell effector function and proliferation to mediate protective antiviral responses during CMV infection. Aim 1 will i) test whether MEF2C is required for mouse NK cell antiviral activity during in vivo MCMV infection and ii) determine if MEF2C augments human NK cell clearance of HCMV-infected targets. Aim 2 will i) determine the MEF2C-dependent metabolic pathways in human NK cells and ii) test whether neutral lipid supplementation can restore effector function and metabolism in MEF2C-deficient human NK cells. Our proposal will delineate a novel transcriptional regulator of human NK cell metabolism that enhances our understanding of basic NK cell biology as well as clinically relevant mechanisms of antiviral immunity.

NIH Research Projects · FY 2025 · 2024-04

PROJECT SUMMARY/ABSTRACT Monogenic variants were once thought to be fully penetrant (all carriers will have disease) and have high expressivity (carriers will have a severe phenotype). However, increased accessibility to sequencing has shown that many monogenic variant carriers are asymptomatic or have milder than expected phenotypes. The factors that affect incomplete penetrance and variable expressivity are unknown. Our preliminary data has shown that common genetic background variants and the specific monogenic variant carried affects penetrance and expressivity within the 200,000 exome release in UK Biobank. Our results show that carrier polygenic risk scores are predictive of carrier phenotype, and that common genetic variants may be interacting with monogenic genes to affect phenotype. We also show in our preliminary results that protein language scores are able to differentiate variants of uncertain significance into loss-of-function (LOF), gain-of-function (GOF), and benign categories. We propose to study how common genetic background and the specific monogenic variant carried affects penetrance and expressivity in a more diverse patient population by collaborating with biobanks across the nation, including the Colorado Center of Personalized Medicine at the University of Colorado under guidance of Dr. Chris Gignoux and the BioMe biobank at Mt. Sinai under the guidance of Dr. Eimear Kenny. In Aim 1, we will understand how common genetic background affects penetrance and expressivity. We will apply polygenic risk scores to predict the phenotype of carriers to understand how common genetic variants affect phenotypes, outside of the causal monogenic variant itself (Aim 1.1). We will also run RHE-mc to detect if gene-by-gene interactions between common variants and the monogenic gene affect phenotype (Aim 1.2). Because genetics research has been primarily focused on studying patients of European ancestry, we aim to make our results accessible to patients of all genetic ancestries by comparing our results of Aim 1.1 and 1.2 across all patients in these diverse biobanks (Aim 1.3). We will also study how differing monogenic variants have differing penetrance and expressivity by applying ESM1b protein language scores in Aim 2. We will apply these ESM1b scores to first classify missense variants of unknown significance in carriers within these biobanks as LOF, GOF, and benign in Aim 2.1. Further, we will also prioritize which monogenic missense variants have the highest impact on phenotype for carriers of multiple missense variants in these biobanks (Aim 2.2). Our findings will not only provide more understanding behind the factors that influence penetrance and expressivity, but also have potential to be applied translationally to identify which monogenic carriers will need more aggressive treatment for their phenotype.

NIH Research Projects · FY 2026 · 2024-04

PROJECT SUMMARY/ABSTRACT Breast cancer (BC) survivors are the largest cancer survivor group (~4 million in the US) given improvements in screening and long-term BC survival. While BC progression is a concern in this group, many BC survivors die of comorbid illness. Specifically, type 2 diabetes (T2DM) is a major comorbidity (prevalence 20%) associated with increased morbidity and mortality in BC survivors. Thus, optimizing T2DM treatment can have a major beneficial impact in clinical outcomes. However, data regarding the optimal T2DM treatment strategies in BC survivors, particularly taking into account novel T2DM drugs, is limited. The harm/benefit ratio of different T2DM treatment approaches is likely significantly different for BC survivors due to an increased risk of T2DM complications (particularly cardiovascular disease [CVD] in setting of cardiotoxic BC treatments), unique harms from T2DM treatments, higher competing risks of death from BC, and differences in baseline QOL. To address this knowledge gap, I plan to develop and validate a simulation model to recapitulate the natural history, management, and outcomes of T2DM in BC survivors (Aim 1). I then will determine the most effective T2DM treatment strategy (according to age, stage, primary BC therapy, BC recurrence, CVD) in terms of glycemic control intensity (intensive vs. moderate) and first-line drugs (metformin, SGTL2i, GLP1ra vs. SGTL2i/GLP1ra combined) for Stage II-III BC survivors 2) (Aim 2). I am an endocrinologist and my career goal is to optimize diabetes care for cancer survivors and other understudied populations with complex comorbidity using innovative simulation modeling approaches. My proposed training plan focuses on the following domains: 1) Advanced statistical and epidemiological methods (quality of life, longitudinal data, and missing data imputation); 2) Simulation modeling and translation into practice; and 3) Leadership in research and career development (scientific communication, grant writing, etc.). I have assembled an interdisciplinary experienced mentorship team with expertise in diabetes, cancer survivorship epidemiology, biostatistics, and simulation modeling. I will complete my training at the Icahn School of Medicine at Mount Sinai, a national leader in research and one of the top 20 medical schools for research in the country. I have a mentorship team committed to the success of my proposal and my development into a competitive researcher for R-level grants

NIH Research Projects · FY 2025 · 2024-04

Project Summary Plant (poly)phenolic compounds are widely acknowledged to have health benefits in humans, and diets high in plant-based foods are associated with good health. Phenolic compounds can act as antioxidants, by scavenging free radicals and preventing free radical formation, and can regulate metabolic reactions by binding to various enzymes. Despite epidemiological evidence that these phytochemicals have health-promoting effects, the mechanisms of action behind their bioactivity remain incompletely understood. The overarching goal of this proposal is to elucidate the mechanisms underlying various biological activities of (poly)phenolic compounds including antioxidant, anti-inflammatory, and other medicinal properties. The specific aims are 1) Systems-level analysis of metabolism upon (poly)phenolic compound addition, 2) Exploring the effect of (poly)phenolic compounds in cell lines and animals, and 3) Searching for synergy by paring (poly)phenols, small-molecule drugs, and nutrient conditions. The complexity and diversity of (poly)phenolic compounds and their biological activities necessitate innovative analytical techniques for systems-level quantitation of metabolic effects. The proposed research will innovate i) a widely applicable method for mapping the mechanism of action of natural products and ii) targeted uses of (poly)phenols as a sole preventive and therapeutic strategy and as a complement to other drugs. To this end, a novel method, termed ‘shotgun metabolomics,’ will be developed. Furthermore, a combination of state-of-the-art mass spectrometry, cleverly designed isotope tracing strategies, and a fundamental thermodynamic principle will be used to obtain and integrate metabolomic, fluxomic, and thermodynamic measurements across cellular metabolism. This integrative approach will expand the coverage of quantitative metabolic analysis. Using this approach, this project will generate and test new hypotheses regarding systemic metabolic rewiring, elicited by (poly)phenols, that contributes to preserving energetic homeostasis in terms of ATP and redox molecules. The proposed systems-level analysis will reveal multi-faceted effects of (poly)phenols on various parts of metabolism, which collectively contribute to cells’ ability to fight stressors and maintain homeostasis. Exploring and elucidating the mechanisms underlying (poly)phenols’ biological activities will promote preventive and integrative health care.

NIH Research Projects · FY 2026 · 2024-04

ABSTRACT Continuous training and career support will nurture junior to mid-career faculties and researchers in Vietnam and Thailand to become regional leaders and driving forces in HIV/AIDS control in Southeast Asia. In response to PAR-22-151, the University of California, Los Angeles (UCLA) proposes to provide Cutting-edge, Customized, and Comprehensive (CCC) capacity building for faculties and researchers at Hanoi Medical University (HMU) in Vietnam and Chiang Mai University (CMU) in Thailand. The partnership is built upon the three institutes’ previous and current research and training collaborations and will leverage the existing research and mentoring infrastructures at UCLA, including the David Geffen School of Medicine (DGSOM), Center for HIV Identification, Prevention, and Treatment Services (CHIPTS), UCLA-Charles R. Drew University (CDU) Center for AIDS Research (UCLA-CDU CFAR), Division of Population and Behavioral Health (DPBH) Center of Excellence (COE), Integrated Substance Abuse Program (ISAP), and University of California Global Health Institute (UCGHI) GloCal Health Fellowship Program. The CCC program will support four junior to mid- level faculty from HMU/CMU each year (two from each institute each year in Years 1-4; totaling 16 trainees) to receive training in three pillars: 1) research (develop research agenda and apply for independent research funding), 2) mentoring (improve skills and curriculum to teach and mentor the next generation of public health professionals), and 3) leadership (nurture leadership skills and ascend into leadership positions in a Southeast Asia HIV Research Advancement Hub [SAHRAH] as a result of this program). Aligned with NIH HIV priorities, the training contents will center around cutting-edge evidence-based pharmaceutical and bio- behavioral strategies to prevent and treat HIV and comorbidities. The trainees will receive customized, hands- on training based on their individualized career development, starting with a 9-month visit at UCLA for intensive engagement in workshops, seminars, courses, and research projects, followed by a one-year structured in- country training encompassing in-country research, summer institutes, cross-country networking events, and exercise of leadership skills within SAHRAH. A highly comprehensive mentorship system, featuring a primary mentor, in-country mentor, transnational mentor, rotational mentor, and peer mentor, will ensure that trainees receive holistic guidance in subject expertise, understanding of local culture and resources, and forging global collaborations. Each trainee will establish individualized SMART (specific, measurable, achievable, relevant, and time-bound) training objectives based on their HIV-related manuscripts, conference presentations, career advancement or research proposals, participation in cross-border projects, mentorship in HIV research, and leadership roles. The program will cultivate SAHRAH with a cadre of multidisciplinary faculties and researchers in Vietnam and Thailand, positioning them to lead the subsequent cycle of Fogarty training program application as leaders in HIV research and training in Southeast Asia.

NIH Research Projects · FY 2025 · 2024-04

PROJECT SUMMARY Obesity is associated with an increased risk of relapse from acute lymphoblastic leukemia (ALL), the most common childhood cancer. We have uncovered a novel mechanism by which fat tissue may make ALL more aggressive and harder to cure. ALL cells found in adipose tissue in mouse models have a higher expression of RANKL (receptor activator of nuclear factor kappa-B ligand) than ALL found in marrow. Exposing ALL cells to adipose tissue ex vivo also increases their expression of RANKL. RANKL is known to contribute to ALL cell expansion in vivo, as well as invasion into bone and the central nervous system (CNS). In the present grant, we will investigate the pathways by which adipose tissue increases ALL expression of RANKL. We will explore this finding using a translational approach, with experiments ranging from bench to mouse to evaluations of clinical samples. We will elucidate which adipose tissue-derived signals are responsible for ALL cell RANKL expression. We will examine whether obesity increases ALL RANKL expression in mice and clinical samples, and explore the relationships between RANKL expression and bone density, CNS invasion, and chemotherapy treatment response. Finally, we will test an FDA-approved treatment, denosumab, in mice to see whether impairing RANKL signaling can improve ALL treatment outcome. These studies may provide a novel strategy for ALL patients to reduce bone loss and fractures, reduce CNS invasion, and potentially improve chemotherapy treatment outcomes.

NIH Research Projects · FY 2026 · 2024-04

ABSTRACT Elevated plasma LDL cholesterol is the main risk factor in cardiovascular disease (CVD), the leading cause of death in the United States. Cholesterol levels are regulated by complex feedback mechanisms that help maintain cellular and plasma cholesterol levels in check. While transcriptional mechanisms that control cholesterol homeostasis, such as SREBPs and LXRs are well described, here we describe a novel post-transcriptional mechanism that is involved in controlling the mRNA stability of Ldlr mRNA. We have identified a family of RNA binding proteins (RBPs) that target specifically mRNAs and are important in cholesterol homeostasis. We show that hepatic loss of one or more of these RBPs in the liver results in increased levels of LDLR mRNA and protein. In Specific Aim 1, we will identify the direct mRNA targets in vivo using CLIP- Seq and we will perform functional genomics to determine the effect of human variants in the LDLR 3’UTR. In Specific Aim 2, we will extend our preliminary data showing that loss of one of our RBPs in the liver profoundly protects from atherosclerosis. Using a ‘humanized’ lipoprotein mouse atherosclerosis model, we have developed the hypothesis that loss of our RBP in the liver promotes uptake of LDL particles, thus protecting from atherosclerosis. Further, we hypothesize that the internalized cholesterol is then preferentially catabolized to bile acids. Thus, our mouse model will allow us to better understand how the liver channels cholesterol taken up from LDL particles to ultimately protect from CVD.

NIH Research Projects · FY 2025 · 2024-04

Project Summary/Abstract The brain uses two strategies to make decisions. Goal-directed decision making relies on prospective consideration of potential outcomes and consequences, using learned action-outcome associations. On the other hand, habits are reflexive behaviors executed without forethought of their consequences. Goal-directed learning is more flexible, but cognitively taxing. Habits require less cognitive control but are relatively inflexible. Balance between these two processes allows behavior to be adaptive when needed, but efficient when appropriate. Dysfunction in this balance or an overreliance on habits causes maladaptive decision making that characterizes substance use disorder and other psychiatric conditions. Despite the importance to understanding adaptive and maladaptive decision making, little is known about the neural circuitry that supports action-outcome learning and habit formation. Recent research in rodents and humans has implicated midbrain dopamine neuron activity in both goal-directed and habit learning. Midbrain dopamine neurons burst fire to unexpected rewards. This signal has been interpreted as the prediction error term needed for habit formation. Recently, dopamine neurons also been found to be involved in aspects of goal-directed learning. It is currently unknown how dopamine could support these two, opposing forms of learning. One way dopamine might achieve this multifaceted function is through projections to subregions of the amygdala. The basolateral amygdala (BLA) has long been known to be involved in goal-directed learning and the central amygdala (CeA) has been implicated in habit formation. Both BLA and CeA receive direct inputs from the lateral ventral tegmental dopamine neurons (VTADA). I will conduct critical, in depth, and hypothesis-driven investigation of the contribution of dopaminergic projections to the basolateral amygdala and central amygdala and their contributions to goal-directed and habit learning. I will receive training in cell-type and projection-specific optogenetic manipulation, fiber photometry dopamine monitoring, and behavioral procedures root in learning theory to diagnose the content of learning and decision strategies. In Aim 1, I will apply in vivo fiber photometry imaging and optogenetic manipulation during a sophisticated behavioral paradigm to characterize the function of the VTADABLA pathway and its necessity for action-outcome goal-directed learning. In Aim 2, I will also apply in vivo fiber photometry dopamine imaging and optogenetic manipulation to uncover the function of VTADACeA pathway and its necessity for habit formation. Completing this project at UCLA ensures I will have access to a highly collaborative network of leading neuroscientists to receive project feedback and training. This award will provide training to help launch me into an independent career role studying maladaptive decision making and its implications for addiction.

NIH Research Projects · FY 2025 · 2024-04

PROJECT SUMMARY Leptomeningeal disease (LMD) is the metastasis of cancer cells into the pia arachnoid and cerebrospinal fluid (CSF), and is a devastating disease with survival rates of 4 months after diagnosis. Lumbar puncture (LP) with cytology is the gold standard for confirming the diagnosis of LMD; however, it has a low sensitivity with the first LP, requiring multiple additional samples to capture circulating tumor cells (CTCs). Flow cytometry and the CellSearch Assay are alternative methods for detection of CTCs in CSF, and they have demonstrated higher sensitivities with the first LP. These approaches detect CTCs and leukocytes as they both express epithelial cell adhesion molecule (EpCAM), and with additional labeled antibodies, such as those for CD45, they are able to distinguish between the two cell types. Although these approaches have significantly improved sensitivity and are quantitative, they unfortunately require liquid handling steps, costly equipment, and trained personnel. Samples therefore need to be sent to a central lab which is expensive and can take 1-2 weeks for results, which is unacceptable considering the low survival rates. Additionally, one LMD treatment corresponds to placing a CSF reservoir in the brain and injecting chemotherapeutics directly into the ventricle/CSF space, which can occur 2-3 times a week. Since LP with cytology is not quantitative, it currently takes months to know if such a treatment has failed, and by then, it is too late. Flow cytometry and the CellSearch Assay can quantify the concentration of CTCs, but they cannot be used for real-time monitoring of CTCs during treatment. An inexpensive, rapid, equipment-free, and user-friendly assay that can be used at the point of care (POC) is the lateral-flow immunoassay (LFA), which has been used to detect pregnancy and COVID-19. Although the LFA has many advantages, it unfortunately is limited to a yes/no answer and is not quantitative. We therefore propose to develop two types of next generation paper-based quantitative POC devices to allow the detection and quantification of CTCs during the LP and therefore eliminate delays in diagnosing LMD. Specifically, these devices will be able to determine the concentration of cells expressing EpCAM. Since these cells include both CTCs and leukocytes, our devices will also simultaneously determine the concentration of leukocytes through CD45. Similar to flow cytometry and the CellSearch Assay, the concentration of cells expressing CD45 (leukocytes) will be subtracted from the concentration of cells expressing EpCAM to estimate the concentration of CTCs. Such devices could also be easily integrated with treatment procedures, such as the one described above for injection of chemotherapeutics, to assess treatment efficacy. Our devices will be tested with synthetic CSF containing varying concentrations of human breast cancer cells and T-cells. Subsequently, a preliminary validation of the two types of devices will be conducted with clinical samples from approximately 25 LMD positive and 25 LMD negative patients at UCLA.

NIH Research Projects · FY 2026 · 2024-04

PROJECT SUMMARY Parkinson’s Disease (PD) may begin in the gastrointestinal (GI) tract. The overall goal of this research is to identify intestinal pathogenic mechanisms in PD that may lead to the identification of gut-biomarkers for early diagnosis as well as gut-directed therapies to halt progression of disease in the premotor phase. The proposed research addresses the hypothesis that mitochondrial dysfunction in the intestinal epithelium causes PD via the gut brain immune axis through two specific aims. The first aim will determine the role of mitochondrial dysfunction in mediating the response of the intestinal epithelium to enteric neuron pathologic α-Synuclein. This will be accomplished through measurement of inflammation and mitochondrial stress in duodenal tissue, isolated crypts and intestinal organoids from a PD model (mice over-expressing human α-Synuclein). In addition, these measures will be evaluated in wild type organoids treated with conditioned media from organotypic cultures of the enteric nervous system in the same PD model. The second aim will test the hypothesis that impaired mitophagy in the intestinal epithelium causes persistent central pathology and motor deficits in a gut-seeding PD model. This will be accomplished through duodenal injection of α-Synuclein preformed fibrils in mice with intestinal epithelial-specific Parkin knockout and wild type mice. This proposed research will provide Dr. Elizabeth Videlock, a board-certified Gastroenterologist, with training in the research skills necessary to study the gut-brain axis in PD. This technical training is a component of a comprehensive career development plan designed to facilitate her transition to independence. Her mentorship team is led by Nigel Maidment, Professor of Psychiatry and Biobehavioral Sciences, who has extensive experience studying dopamine neurotransmission in rodent models of PD and a strong track record in mentoring trainees to independence. Co-mentors will provide mentorship in assessment of the enteric nervous system (Million Mulugeta), intestinal organoids (Martin G. Martin), and leadership skills (Lin Chang). In addition, an advisory panel will provide mentorship for content related to the role of the gut in PD (Yvette Taché, Michael Camilleri) and mitochondrial morphology and metabolism in epithelial cells (Leanne Jones, Rajat Singh). The strength of the clinical and basic science programs in metabolism, neurodegenerative disease and the gut-brain axis make UCLA the perfect institution to support this interdisciplinary proposal.

NIH Research Projects · FY 2026 · 2024-03

PROJECT SUMMARY/ABSTRACT Osteogenesis imperfecta (OI) is among the most common osteochondrodysplasias. It is genetically heterogenous, resulting from mutations in 22 different genes. Regardless of the genotype, the disorder is characterized by brittle bones with recurrent fractures due to impaired bone quantity and quality. OI is also phenotypically heterogeneous with mild, moderate, severe, and perinatal lethal forms of disease. The incidence is estimated at 1/20,000 births and around 20,000 to 50,000 Americans have OI.1,2 About 85% of OI cases result from dominant mutations in COL1A1 or COL1A2 which encode the α1 and α2 chains of type I collagen, the major protein in bone.3 Rare forms of OI are from mutations in other genes involved in type I collagen synthesis, modification, trafficking, or osteoblast function.4 In the United States, there are no therapeutic agents labeled for use in OI. OI is typically treated with bisphosphonates and supplemented with calcium and vitamin D.3,5 Bisphosphonates are anti-resorptive agents that induce osteoclast apoptosis and are indicated for use in osteoporosis and diseases with pathologic bone resorption.6 While bisphosphonates have been effective in increasing bone mineral density in OI, their effect on fracture risk is uncertain and may cause OI bone to become even more brittle.7 This uncertainty, combined with our growing knowledge of OI pathophysiology, have driven the field to search for alternative treatment strategies. Intermittent parathyroid hormone, anti-sclerostin therapy, and anti-TGFβ therapy have all been clinically tested in patients with OI. In each study, only a subset of patients exhibited a beneficial response. In OI, the mechanistic etiology of the variability in response to treatment is not understood and significantly affects patient care. I hypothesize this response variability in OI results, in part, from a genotype dependent accumulation of misfolded type I collagen. Type I collagen is co-translationally inserted into the endoplasmic reticulum (ER) lumen as procollagen alpha chains. There, they are post-translationally modified and fold before exiting the ER. In OI due to glycine substitutions or splicing mutations, misfolded type I procollagen accumulates in the ER lumen of osteoblasts producing ER stress. In addition to collagen, many other cellular products are processed through the ER including transmembrane receptors, extracellular matrix components, and secreted ligands. Under ER stress, the cell may not be able to synthesize and process normal levels of these cellular products . I will test the hypothesis that ER stress in OI is genotype dependent and leads to dysregulated osteo- progenitor/osteoblast signaling function due to receptor/ligand signaling cascades. This proposal will establish that ER stress is more than a cellular response – it is clinically important and genotype dependent in OI. It also provides preclinical data for a new treatment strategy for OI and adds to the growing view that the OI phenotype is not simply due to a structurally defective extracellular matrix.

NIH Research Projects · FY 2026 · 2024-03

PROJECT SUMMARY This proposal describes as 5-year mentored career development and research plan that facilitates the transition of Dr. Sinifunanya Nwaobi to an independent clinician scientist. Dr. Nwaobi is a Pediatric Neurologist who specializes in Headache and Pain Medicine at the UCLA Goldberg Migraine Program. Her overall career goal is to focus on managing adult and pediatric headache while leading translational research that will directly impact her patients’ care. One main career objective is to approach headache and pain research through the lens of a glial biologist, with a focus on astrocytes. The research proposal elucidates the bi-directional relationship between sleep and migraine by examining the specific mechanisms by which sleep modulates migraine pathophysiology. Aim 1 interrogates how both homeostatic and circadian components of sleep impact acute and chronic migraine using three clinically relevant rodent models of migraine. Aim 2 examines astrocytic, neuronal, and receptor-specific adenosine signaling to identify a drug-targetable mediator of the sleep-migraine connection. This tailored proposal builds upon Dr. Nwaobi’s prior experiences in glial biology, while expanding her skillset to include novel technologies that allow for minimally invasive in vivo monitoring of brain activity which are broadly applicable to the field of neuroscience. This research proposal will also expand her expertise in electrophysiology, in vivo fiber photometry, and large data statistical analyses. She will gain increased research exposure to the fields of headache, sleep, and glial biology. This work lays the foundation for future studies that will be the topic of subsequent K- and R- funding proposals. Importantly, this career development plan provides Dr. Nwaobi with world-class mentorship from leading experts in fields of headache medicine, circadian physiology, and glial biology. This diverse mentorship works to ensure her successful transition to an independent clinician scientist, foster collaborative research, and maximize the translational impact of the proposed studies. Overall, the proposed career development and research plan will directly advance the field of migraine with a focus on targeting drug-modifiable processes, while advancing Dr. Nwaobi towards research independence as a clinician scientist in headache and pain medicine.

NIH Research Projects · FY 2026 · 2024-03

Project Summary The benefit of MAPK inhibitor (MAPKi) therapy for melanoma has been limited to patients with BRAFV600 mutant melanoma. Since the development of MEK inhibitor (MEKi) combination to suppress acquired resistance to type I RAF inhibitor (RAFi), progress to further suppress resistance has stalled. Similarly, there has been little progress in the development of MAPKi therapy for the other ~50% of patients with BRAFV600 wildtype melanoma, due to contra-indication of type I RAFi and rapid resistance to MEKi monotherapy. Our overarching hypothesis is that a comprehensive proteogenomic understanding of how the full-spectrum of melanoma subtypes evolves MAPKi resistance will renew clinical interest in the development of MAPKi-based combinations. Recent studies, including ours, support the notion that a wide-spectrum (BRAFV600MUT, NRASMUT, NF1-/-, triple WT) of melanoma is highly addicted to the MAPK pathway. The lack of efficacy of single-agent MAPKi (e.g., MEKi) therapy belies this exquisite pathway addiction because of an inability to control pharmacologically MAPK pathway reactivation. Thus, effective preclinical strategies that directly tackle MAPK pathway reactivation as well as downstream or parallel phenotypes of acquired resistance warrant clinical development. To anticipate clinical resistance to MAPKi across melanoma subtypes, we will build a comprehensive patient-derived xenograft (PDX) bank of not only MAPKi-naïve melanoma but also subclones with acquired MAPKi-resistance. We will combine sequencing (whole-genome, exome, transcriptome) and mass spectrometry (proteome, phosphoproteome), coupled with temporal analysis of transcriptomes at the single-cell level and chromatin accessibility, to provide a multi-omic landscape of therapeutic resistance evolution in a highly clinically relevant platform (Melanoma Resistance Evolution Atlas or MREA) to functionalize therapeutic vulnerabilities. We will test our hypothesis with the following Specific Aims: (1) Discover the proteogenomic landscape of melanoma with acquired MAPKi-resistance, (2) Evaluate combinatorial strategies targeting recurrent drivers of MAPKi-resistance, and (3) Create multi-omic data integration tools to identify therapeutic vulnerabilities of acquired MAPKi-resistance. MREA version 1.0 (years 1- 2; 28 PDX models) will encompass BRAFV600MUT and NRASMUT melanoma, whereas MREA v2.0 (years 2-4; additional 60 PDX models) will encompass the full spectrum of cutaneous melanoma subtypes. To nominate resistance-specific alterations (RSAs) for functional validation and in vivo preclinical trials, we prioritize RSAs based on critical criteria: high recurrence, multi-omic convergence, druggability/human safety data, orthogonal support from the literature and additional public and custom databases, and potential of RSA-targeting to yield synergy with immunotherapy.

NIH Research Projects · FY 2026 · 2024-03

PROJECT SUMMARY/ABSTRACT The great majority of people who are infected with Mycobacterium tuberculosis (Mtb) do not develop active disease but contain the bacterium in a dormant state, a condition referred to as latent tuberculosis infection (LTBI). Many of these people reactivate tuberculosis (TB) later in life, often in association with an immunocompromised status, such as co-infection with HIV, immunotherapy for cancer or other diseases, aging, etc. An estimated 2 billion people on earth have LTBI and constitute a huge reservoir of people at risk of reactivation TB unless treated and the persistent Mtb state eliminated. Current treatment regimens for LTBI are long and burdensome, negatively impacting treatment completion. The study proposed herein seeks to examine a potentially much shorter regimen requiring as little as one or two weeks. If successful, and then replicated in humans, such a short-term regimen could change clinical practice. Our group pioneered the use of an artificial intelligence-enabled parabolic response surface (AI-PRS) platform allowing rapid identification of the most effective drug-dose combinations for treating active TB by testing only a small fraction of the total drug-dose efficacy response surface. This approach determined that bedaquiline (BDQ), clofazimine (CFZ), and pyrazinamide (PZA) at optimal dose ratios were highly synergistic and either by themselves or with a fourth drug were much more effective than standard treatment, achieving relapse-free cure in mouse models of active pulmonary TB within 3 weeks - an ~85% reduction in time versus the standard regimen for treating drug-sensitive TB. Here we propose to evaluate this 3-drug core regimen (BCZ) in non-human primates (NHPs) for treatment of LTBI in a setting mimicking co-infection with HIV. As a fourth drug is not needed to prevent emergence of resistance as in active TB therapy, the three core BCZ drugs should be more than sufficient for treatment of LTBI; current approved regimens comprise 1 or 2 drugs. To achieve our goals, we shall leverage the two MPIs’ expertise with AI-PRS technology and the NHP LTBI model. We shall initially perform limited pharmacokinetic (PK) studies of BCZ to optimize drug doses in NHPs such that blood levels are equivalent to the optimal human doses determined in a PK evaluation of these 3 core drugs as part of a similar AI-PRS derived ultra-short 4-drug regimen for treating active TB in a just initiated human study. We shall then infect NHPs with a low dose of Mtb by aerosol to establish LTBI infection; then not treat (Negative control - all expected later to reactivate TB with SIV co-infection), treat with BCZ for 1, 2, or 4 weeks, or treat with the approved regimen of isoniazid and rifapentine for 3 months (Positive control – none expected later to reactivate with SIV co-infection); and finally co-infect with SIV and monitor for reactivation TB. If short-term BCZ treatment prevents reactivation TB, this study will pave the way for a definitive treatment-shortening trial of BCZ in LTBI and potentially revolutionize the treatment of LTBI, hastening the elimination of the TB reservoir and subsequently TB.

NIH Research Projects · FY 2025 · 2024-03

PROJECT SUMMARY Radiation therapy (RT) is a standard-of-care oncological treatment for the central nervous system (CNS). However, during cranial RT, normal brain tissue adjacent to the tumors is inevitably irradiated, causing transient reversible abnormalities as well as progressive irreversible late toxicities. Approximately 100,000 patients with primary and metastatic brain tumors per year in the United States survive long enough (>6 months) to develop radiation-induced brain injury, including cognitive impairment and/or neurological sequelae, significantly impeding the quality of life. These symptoms occur in 50-90% of adult patients after treatment and can be seen without clinical and radiographic evidence of histological changes. In this proposal, we aim to establish a novel, robust, cell-based 3D brain organoid model that closely mimics the complexity of the human brain microenvironment, serving as a platform to study pathophysiological processes and neuroinflammation induced by RT in the normal brain tissue. Further, leveraging the established UCLA portfolio of radiation mitigators, the brain organoid model could be a promising screening and testing platform that recapitulates the human brain responses to therapeutic agents. Overall, this proposal will not only characterize the real-time and dose-dependent physiological responses of normal brain tissue to ionizing radiation, but will also provide proof-of-principle evidence to support the use of human brain organoid model as a platform for screening and testing radiation mitigators, enabling thus the development of adequate countermeasures against radiation. Considering that patient-derived iPSCs may be leveraged to develop personalized testing models, our novel biomimetic model holds significant promise in the screening of patient-specific radiation mitigators in the era of precision medicine in the near future.

NIH Research Projects · FY 2025 · 2024-03

PROJECT SUMMARY/ABSTRACT Social stability for many species is maintained via social hierarchies, wherein displaying subordinate behavior to higher ranking individuals is key. A subordinate social rank influences the brain and behavior by altering neural circuitry and the production and signaling of neuromodulators, such as steroid hormones and neurotransmitters. For example, androgens tend to be negatively correlated with a subordinate social rank, while the neural expression of the serotonin 1A (5-HT1A) receptor is positively associated with subordinate behavior. Although clear relationships have been established between a subordinate social status, the brain, and behavior, the molecular and neural mechanisms regulating these changes are not known. A major challenge in elucidating these mechanisms is that social rank is often tied to both physiological and behavioral traits, making it difficult to distinguish the effects of neuromodulators (e.g., androgens and serotonin) on individual traits associated with social subordination. Thus, the use of novel model organisms, in which distinct traits of subordinate social status can be studied in isolation, is necessary to enhance our understanding of the neuroendocrine regulation of subordination. The proposed work will use state-of-the-art sequencing and genome editing technologies to identify genes and cell types in the brain that govern subordinate social status in the African cichlid fish Astatotilapia burtoni. A. burtoni is a highly social species in which males display subordinate or dominant behavior based on social status. Recent work showed that androgen receptor (AR) mutant males generated via CRISPR/Cas9 gene editing do not exhibit distinct traits of dominant social rank. For example, ARα mutants do not perform dominant behaviors (mating or aggression), whereas ARβ mutants lack bright coloration and show reduced testes growth, making these fish an excellent tool for taxing the molecular and neural systems controlling distinct aspects of subordinate social status. In Specific Aim 1, I will identify cell types and their genetic signatures in the hypothalamus of dominant WT males and subordinate WT and AR mutant males using single-nucleus RNA sequencing. In Specific Aim 2, I will determine the role of androgens in regulating subordinate social status by measuring physiological and behavioral traits of social rank in subordinate AR mutants. Finally, in Specific Aim 3, I will generate novel mutant A. burtoni lacking the 5-HT1Aβ receptor using CRISPR/Cas9 gene editing to assess the role of serotoninergic signaling in governing social subordination. Based on preliminary data showing that AR and AR mutants display distinct physiological responses to social suppression, I predict these mutants will have cell type-specific gene expression patterns that mirror different aspects of subordination. Moreover, given the known relationship between androgen and serotoninergic signaling, I expect to observe contrasting deficits in physiological and behavioral traits of subordination in AR and 5-HT1Aβ mutants that reveal the roles of these systems in controlling subordinate social status. Collectively, these studies will yield important insights into the basic neural and molecular mechanisms that regulate subordination in social animals, including humans.

NIH Research Projects · FY 2026 · 2024-03

PROJECT SUMMARY/ABSTRACT Immunocompromised patients, including those requiring immunosuppressive therapy following organ transplantation, are at high risk for severe disease from SARS‐CoV‐2. As SARS-CoV-2 rapidly transitions from a pandemic virus to endemic status, like influenza, seasonal vaccinations against emerging variants will likely become the primary tool for limiting morbidity and mortality. While the efficacy of vaccination against SARS-CoV- 2 has been very promising, specific populations have been identified who are at increased risk of failing to develop protective immunity. Immunocompromised populations respond poorly to SARS-CoV-2 vaccination, particularly solid organ transplant (SOT) recipients receiving immunosuppressive therapy. Within SOT recipients, the type and dose of immunosuppressive therapy have further been shown to impact vaccine efficacy. Patients receiving mycophenolate mofetil (MMF) immunotherapy, which functions by preventing B and T cell proliferation/activation, as well as leukocyte recruitment, have the poorest humoral and cellular response post- vaccination for SARS-CoV-2. Preliminary evidence suggests that discontinuing MMF before vaccination improves humoral responses in SOT recipients. This project will test the hypothesis that coordinated innate and adaptive dysregulation pre-vaccination driven by MMF immunosuppressive therapy diminishes the quality, quantity, and durability of cellular and humoral immunity to SARS-CoV-2 in kidney transplant recipients. In Aim 1, we will characterize the impact of MMF on the generation, quality, and maintenance of adaptive immune responses to SARS-CoV-2 vaccination in SOT recipients. We will use validated assays to quantify and functionally profile humoral and cellular immunity to SARS-CoV-2. In Aim 2, we will define the pre-vaccine immunological determinants of a protective host immune response to SARS-CoV-2 vaccination in kidney transplant recipients and identify the mechanisms of MMF-diminished immunity. We will use systems biological tools to comprehensively profile, at the single-cell level, the peripheral immune system prior to vaccination. In Aim 3, we will determine how pre-vaccine MMF reduction impacts the host immune response to SARS-CoV-2 booster vaccination in kidney transplant recipients. Together, these data will provide a comprehensive, mechanistic understanding of how MMF immunotherapy dysregulates the immune system in SOT recipients and how this dysregulation impacts the induction and durability of protective immunity against SARS-CoV-2. This knowledge will allow the development of targeted strategies to correct or circumvent MMF-driven immune dysregulation, thereby permitting efficacious responses to SARS-CoV-2, and other vaccines, in SOT recipients and other at-risk populations.

NIH Research Projects · FY 2026 · 2024-02

PROJECT SUMMARY The gold standard treatment for specific phobias is exposure therapy, wherein the individual repeatedly faces the object of their fear. However, for many patients, the level of distress prohibits them from either starting or completing exposure therapy. The objective of this application is to use focal neuro-reinforcement based on decoded fMRI information (from the ventral temporal temporal cortex) to reduce fear responses to feared animal stimuli (e.g., spiders, birds) in individuals with phobias, directly and unconsciously in the brain, without repeatedly consciously exposing participants to their feared stimuli. Because the induced representations are unconscious, participants do not experience negative emotional responses and the procedure is double-blind placebo-controlled, thus providing a level of experimental rigor not afforded to standard psychological therapies. Extending from our pilot data, we are positioned to test the mechanisms and behavioral outcomes of a novel treatment for phobias that at the same time advances our understanding of the role of consciousness in fear responses and their change over time. The specific aims are to: (1) confirm that our method engages the neurobiological target (amygdala reactivity to images of feared animals) in a population of individuals with specific phobias of animals; (2) quantify how changes in amygdala reactivity with neuro-reinforcement mediate changes in behavioral outcomes, as measured by attentional capture, approach/avoidance behavior, or subjective fear ratings, immediately post neuro-reinforcement; (3) assess the longer term effects four weeks after neuro-reinforcement; and (4) explore the impact of three dosage levels of neuro-reinforcement to identify the optimal dosage for future research. If proven effective, the results will inform applications for other fear- related disorders, such as posttraumatic stress disorder, social anxiety disorder and panic disorder.

NIH Research Projects · FY 2026 · 2024-02

PROJECT SUMMARY/ ABSTRACT Breathing is a remarkable behavior fundamental to life that mediates gas exchange to support metabolism and regulate pH. A reliable, non-stop, robust rhythmic pattern of respiratory muscle activity is essential for breathing in mammals. Failure to maintain a normal breathing pattern in humans suffering from sleep apnea, apnea of prematurity, congenital central hypoventilation syndrome, hyperventilation syndrome, Rett syndrome, and perhaps Sudden Infant Death Syndrome, leads to serious adverse health consequences, even death. Various neuro- degenerative diseases, such as Parkinson's disease, multiple systems atrophy, and amyotrophic lateral sclerosis, are associated with sleep disordered breathing that appear to result from the loss of neurons in brain areas controlling breathing. If breathing is to be understood in normal and in pathological conditions, the mechanisms for breathing central pattern generation must be revealed. We focus on two brainstem sites essential for generation of the normal breathing pattern, the preBötzinger Complex and the retrotrapezoid nucleus/parafacial respiratory group. We propose a broad series of experiments both in vivo and in vitro in rodents using state-of-the-art techniques to significantly advance our under- standing of respiratory rhythm and pattern generation to provide an extraordinary window into the mechanisms underlying the neural control of breathing. Such advancements will be foundational for development of highly novel therapies for treating human diseases of breathing.

NIH Research Projects · FY 2026 · 2024-01

Project Summary Over 200 million people are infected with malaria every year. An effective and long-lasting vaccine will be essential for the elimination and eradication of malaria in Sub-Sharan Africa and worldwide. Though WHO- approved circumsporozoite protein (CSP) protein vaccine RTS,S is the only vaccine in current use, it provides <50% protection that is also short lived. The proposed research will delve into the humoral immunity of the whole sporozoite vaccine (PfSPZ), a model system to identify protective immune responses beyond the immunodominant epitope CSP - essential insights needed to create new, highly effective malaria vaccines. This proposal describes a five-year career development plan to study humoral immunity to the malaria- causing pathogen Plasmodium falciparum. Though antibodies are important for PfSPZ-mediated protection, the protective antibody targets and functions remains unknown. Further, PfSPZ's efficacy drops in malaria- exposed individuals and how pre-existing anti-malarial antibodies affect PfSPZ vaccination remains unanswered. Our preliminary systems serology analysis of malaria naïve PfSPZ vaccinees has suggested a new protective role for IgM antibodies to SSP2/TRAP, a malaria host cell recognition and invasion protein, and validated our approach. The studies proposed here are to 1) define the functional antibody correlates of protection in malaria-exposed individuals and the effect of pre-existing immunity 2) identify new correlates of protection with a whole-proteome approach, and 3) define mechanisms of anti-sporozoite immunity of SSP2/TRAP IgM antibodies. These aims will be carried out with human serum from PfSPZ vaccination and controlled human malaria infection (CHMI) challenge trials in malaria-naïve and exposed individuals. The candidate is currently an Associate Physician at Brigham and Women's Hospital, Instructor in Medicine at Harvard Medical School (HMS), and Research Fellow at the Ragon Institute with an ongoing commitment of 80% time to research. The proposal is supported by an expert mentor in humoral immunology, HMS Professor Facundo Batista, and co-Mentored by expert in systems biology MIT Professor Douglas Lauffenburger. The candidate is supported by a SAC containing an expert in phage display serological assays, HMS Professor Stephen Elledge, an expert in malaria vaccinology, NIAID Chief of Cellular Immunology Dr. Robert Seder, and expert in malaria host-pathogen interactions and pre-erythrocytic immunity University of Washington Associate Professor Noah Sather. Building on the candidate's doctoral training in malaria pathogenesis and genomics, this proposal will further his training in humoral immunology, systems biology, and bioinformatics as well as research scientist-focused professional development and responsible conduct of research coursework. Completion of this comprehensive training plan will enable the candidate to create a successful and unique research program, obtain independent funding, and transition to running an independent laboratory focused on malaria antibody immunology, phage display serologic assay tool development, and vaccinology.

NIH Research Projects · FY 2026 · 2024-01

Title of Project: “Solving longstanding mysteries in plasma triglyceride metabolism” PROJECT SUMMARY/ABSTRACT The objective of this Multiple Principal Investigator (PI) R01 grant is to solve persistent mysteries in the molecular physiology of plasma triglyceride (TG) metabolism. The PIs, Loren Fong (UCLA) and Michael Ploug (Finsen Laboratory, Copenhagen), are international leaders in TG metabolism. Fong, a cell biologist and physiologist, discovered that GPIHBP1, an endothelial cell (EC) protein, captures LPL within the interstitial spaces (where it is secreted by parenchymal cells) and moves it to the capillary lumen. Ploug, a physiologist and protein chemist with specialized expertise in biophysical methods, quantified GPIHBP1–LPL interactions; showed that GPIHBP1 stabilizes LPL; and discovered that ANGPTL4 inhibits LPL activity by catalyzing unfolding of LPL’s hydrolase domain. For 11 years, the UCLA and Finsen Laboratory groups have collaborated on the physiology and biophysics of TG metabolism, publishing 21 papers in top-tier journals. They discovered that LPL is active as a monomer, dispelling dogma that it is a homodimer; solved the atomic structure of the GPIHBP1–LPL complex; elucidated the function of GPIHBP1’s acidic domain; and discovered a new human disease (chylomicronemia from GPIHBP1 autoantibodies). The latter discovery has saved lives. They are now focusing on longstanding mysteries in TG metabolism. In Specific Aim 1, they will define the function of apolipoprotein regulators of LPL activity (APOA5, APOC2). They will build on their discovery that APOA5 deficiency reduces intracapillary LPL levels and a recent in vitro discovery (by their collaborator Robert Konrad) that APOA5 suppresses the ability of ANGPTL3/8 to inhibit LPL activity. They will test the ability of recombinant APOA5 to increase intracapillary LPL levels, and they will define the molecular basis for APOA5–ANGPTL3/8 and ANGPTL3/8–LPL interactions. They will also build on their discovery that APOC2 stabilizes the conformational integrity of LPL’s hydrolase domain— even in the presence of ANGPTL4. They will now test whether APOC2 protects LPL from inhibition by ANGPTL3 and ANGPTL3/8, and they will define the impact of APOC2 on LPL’s lid, which regulates substrate entry into LPL’s catalytic pocket. In Specific Aim 2, they will use stable isotope labeling to study the turnover of GPIHBP1 and LPL in tissues and determine the extent to which LPL turnover is altered by fasting/refeeding and APOA5 deficiency. They will test the hypothesis that GPIHBP1 is a long-lived protein that moves bidirectionally across ECs and that LPL has a short half-life and largely moves unidirectionally (towards the capillary lumen). In Specific Aim 3, they will investigate LPL expression in lower vertebrates (where GPIHBP1 is absent) with the goal of better understanding mammalian LPL biology. They will explore the hypothesis that LPL in lower vertebrates is produced by capillary ECs (obviating a requirement for GPIHBP1) and that LPL production in capillary ECs has been retained in mammals. Fong and Ploug are ideally positioned, with outstanding collaborators and unique tool chests of reagents and experimental methods, to solve each of the three longstanding mysteries in plasma TG metabolism. They expect that their work will transform textbook descriptions of intravascular lipolysis.

NIH Research Projects · FY 2026 · 2024-01

PROJECT ABSTRACT Colonization factors that facilitate establishment in the complex and competitive environment of the gastrointestinal (GI) microbiome are still relatively unknown, but knowledge of these factors will be crucial for understanding the formation of this ecosystem and reveal novel therapeutic avenues to manipulate this community. Serving as potential colonization factors, Diversity Generating Retroelements (DGRs) are genetic elements found in bacteria, archaea, and their viruses that are capable of accelerating evolution by rapidly diversifying ligand binding proteins to alter their ligand recognition. The GI microbiome is the most enriched ecosystem for DGRs known to date, but the role of DGRs within the microbiome remains completely unexplored. Therefore, the overarching goal of this proposal is to understand how DGR-driven genotypic variation contributes to adaptive bacterial phenotypes in the GI microbiome, especially in response to dynamic shifts in the environment, such as during colonization or from perturbations to the community. The candidate will use five carefully selected strains of Bacteroides, each of which contains a similar but non-identical DGR that diversifies either a pilus tip adhesin or a periplasmic protein. In Aim 1, he will uncover factors that control DGR activity in Bacteroides spp. In Aim 2, he will characterize the in vivo roles of the diversified proteins and identify other proteins that functionally interact with these diversified proteins. Lastly, in Aim 3, the candidate will determine the selective fitness advantages conferred by DGR-directed accelerated protein evolution. These aims require the application of genetic systems to manipulate Bacteroides genomes, RT-qPCR, genome-wide Tn-insertion sequencing, tandem mass spectroscopy, deep sequencing, computational methods to measure single nucleotide variation, and gnotobiotic mouse models. Practical implications of this work include the identification of DGR-encoded and host-encoded factors that control DGR activity in Bacteroides, characterization of the functions of Bacteroides diversified proteins, and an understanding of how diversification can be utilized to create selective fitness advantages in complex microbial communities. Insights derived from this proposal will ultimately be developed into a toolkit for engineering adaptative colonization systems in beneficial microbes that will facilitate their efficient engraftment into disrupted microbiomes to reverse the dysbiotic states that are often associated with diseases such as obesity, inflammatory bowel disease, and cardiovascular disease. Included in this proposal is a detailed career development plan that outlines a five-year timeline for the candidate that includes hands-on and didactic training in structural biology, bioinformatics, and ecology and evolution. It also details a diverse, multidisciplinary, and complementary advisory team, including an experienced primary mentor, who will guide the candidate in both scientific inquiry and career development. By the conclusion of this award, a successful transition to independence is anticipated to establish an R01-funded research program using DGR- driven technologies to engineer microbiomes.

NIH Research Projects · FY 2026 · 2024-01

ABSTRACT Astrocytes are ubiquitous CNS glial cells that make extensive contacts with neurons. Astrocytes serve diverse roles, including ion homeostasis, neurotransmitter clearance, synapse formation/removal, synaptic modulation, and contributions to neurovascular coupling. Astrocytes are widely implicated in disease and in regulating animal behaviour. Astrocytes are thus critical components of neural circuits and their behavioral outputs. How astrocytes perform such varied physiological roles is a topic of intense worldwide investigation with many fascinating open questions. An exciting discovery made by us and others over the last few years is that astrocytes are heterogeneous, displaying CNS region and neural circuit-specific properties and functions. Exploring the molecular basis and function of astrocyte diversity within specific neural circuits is emerging as an important, innovative research frontier. One outstanding open task is to understand functions of molecularly defined astrocytes in specific CNS areas and to determine how they regulate neural circuits and contribute to behaviors associated with those nuclei. We address this topic for a specific population of Crym+ (protein: μ-crystallin) striatal astrocytes in relation to motor and goal-directed behavior. Interestingly, Crym is downregulated in postmortem striatal tissue in some basal ganglia diseases, implying that understanding how these astrocytes regulate neural circuits physiologically may, in the long term, inform about disease mechanisms. However, almost nothing is known physiologically about either μ-crystallin or about Crym+ striatal astrocytes in the CNS. Based on unexpected and exciting preliminary data, we hypothesize that striatal astrocytes defined by Crym regulate essential astrocyte-neuron interactions within CM striatal microcircuits that control motor and goal-directed behavior. The preliminary data to support this hypothesis are compelling and new. Specific Aim 1 will evaluate how striatal astrocyte-specific CRISPR/Cas9-mediated Crym deletion affects MSNs and astrocytes. Specific Aim 2 will study MSN activity in vivo during behavior following striatal astrocyte Crym deletion. Specific Aim 3 will explore molecular mechanisms of striatal astrocyte Crym (μ-crystallin) in relation to striatal-dependent behaviors. Completion of these aims will advance markedly our understanding of striatal astrocyte-neuron interaction mechanisms and of μ-crystallin. We believe our studies will also be paradigmatic for understanding astrocyte diversity within neural circuits and the functions that such specializations serve in relation to the striatum and the basal ganglia circuitry.