University Of California, San Diego

NIH Research Projects · FY 2025 · 2022-07

PROJECT SUMMARY A predoctoral training program in Chemistry-Biology Interfaces (CBI) at University of California, San Diego (UC San Diego) will leverage our historical strengths in interdisciplinary research and join diverse faculty for a robust training environment. UC San Diego has historically excelled at the interface of chemistry and biology, and the renewed support from the University has ensured a strong and vibrant program in the future. Many of the training faculty in this program are new to the University (within the past 10 years), and the collaborative bonds established in this proposal represent the best of interdisciplinary training. The proposal aims to train 10 students each year, with 20% of these slots supported by a match from the Graduate Dean, starting in their second year of graduate studies, and offering support for two years. The proposal establishes a special curriculum for students who will participate in research within preceptor laboratories in Department of Chemistry and Biochemistry, Skaggs School of Pharmacy and Pharmaceutical Sciences, or Pharmacology. The respective Deans/Directors from each of these divisions/centers have offered significant institutional support, including the topping off of tuition/fees and stipends, providing additional trainee slots in the form of fellowships, and assisting administrative and organizational costs associated with this program. The curriculum we have put together offers a training and personal/professional growth experience that will be unique to this program. This includes required coursework in Chemical Biology and Scientific Ethics (with a Scientific Ethics refresher workshop); a CBI Seminar Series that invite world-class scientists; a CBI Workshop that focuses on research, personal, and professional growth; an annual Career Day; an annual Industrial Tour; an annual CBI Symposium of research accomplishments; and regular interaction/feedback from the world-class faculty in our CBI faculty. Given our strengths for interdisciplinary and collaborative research and the outstanding pool of qualified trainees, we believe that CBI at UC San Diego offers an excellent and unique training opportunity.

NIH Research Projects · FY 2024 · 2022-07

Abstract Acute respiratory distress syndrome (ARDS) is characterized by pulmonary endothelial inflammation that leads to alveolar edema and poor gas exchange. It has a high mortality, and effective treatment options to date are limited. Acute kidney injury increases the mortality from ARDS and there is substantial evidence that kidney injury can directly worsen the lung injury. The mechanisms underlying this kidney-lung interaction are not well understood and could hold therapeutic potential. Following renal ischemia reperfusion injury (IRI), endogenous stress molecules (DAMPs or damage associated molecular patterns) are released from dying renal tubular cells and bind to pathogen recognition receptors (PRRs) on neighboring cells, initiating an inflammatory cascade that worsens renal injury. In preliminary data we have already seen that renal derived DAMPs cause upregulation of inflammatory cytokines and MAPK activation in uninjured renal tubular epithelial cells. Expanding this model to kidney-lung cross talk, human pulmonary endothelial cells exposed to renal tubule-derived DAMPs were found to upregulate inflammatory cytokines and specific PRRs. These preliminary data also revealed that NOD2, a PRR known to play a key role in acute kidney injury, was disproportionately upregulated when compared to other PRRs. Our lab has previously shown that NOD2 knockout protects mice from renal IRI, and preliminary data suggest that inhibition of NOD2 via pharmacologic blockade decreases the inflammatory response of renal tubular epithelial cells to renal derived DAMPs. The hypothesis of this proposal is that NOD2 plays a critical role in lung injury following renal IRI by inducing proinflammatory responses in the pulmonary microendothelium, contributing to ARDS. Given the importance of microvascular endothelial cells in the pathogenesis of ARDS, this proposal focuses on the role of NOD2 on injurious responses in pulmonary microvascular endothelial cells after renal IRI. I will focus on the canonical NOD2 signaling pathways in pulmonary microvascular endothelial cells in response to renal derived DAMPs and also use an in vivo model of renal IRI to correlate NOD2 activation with lung injury. This proposal will provide important new knowledge and skill sets needed to set the stage for the development of my career as a physician-scientist. The work proposed in this application will be conducted in a rich training environment at UC San Diego and the Scripps Research Institute with an exceptional interdisciplinary mentoring team including leaders in the field of innate immunity, endothelial cell biology, and ARDS.

NIH Research Projects · FY 2025 · 2022-07

Project Summary This proposal for pre-doctoral training on “Bioengineering Research and Technology Development in Cardiovascular in Cardiopulmonary Health and Disease”, aims to train outstanding and diverse predoctoral bioengineering students in applying quantitative and integrative interdisciplinary approaches to basic and translational research in cardiopulmonary, vascular, blood and sleep pathophysiology and in developing novel technologies for the diagnosis, treatment and clinical management of cardiovascular and cardiopulmonary diseases. The curriculum is built on four intersecting technology themes that the Bioengineering training faculty are expert in: (a) Biomechanics and Mechanobiology; (b) Biomaterials, Cell and Tissue Engineering; (c) Computational and Systems Biology; and (d) Imaging and Biophotonics. Trainees will take coursework with a concentration in two of these themes. Training faculty from the biomedical sciences will serve as required interdisciplinary co-mentors in the major scientific areas including basic and translational cardiopulmonary, vascular and blood research. The goal is to develop a new generation of bioengineers who become innovators in research and technology development for improving cardiovascular health. The leadership team has three MPIs: Dr. Andrew McCulloch (contact PI), chairs the Steering Committee (SC) and is responsible for administration, admissions and evaluation. Dr. Karen Christman will be primarily responsible for translational research training and Dr. Geert Schmid-Schönbein will oversee program-specific activities including curriculum, seminars, and the annual retreat and symposium. The training faculty includes outstanding and well-funded bioengineers, basic biomedical scientists, physician-scientists and public health experts with exceptionally strong records of collaborative research training. The SC has established effective recruitment, admission, training and evaluation procedures that ensure a large and diverse pool of well-qualified candidates, 100% retention, and excellent outcomes. The curriculum will include required program-specific courses in Cardiovascular Physiology, Molecular Biology of the Cardiovascular System, Patient-Centered Clinical Medicine for Bioengineers, Data Science for Cardiovascular Bioengineering, Responsible Conduct of Research and Rigor and Reproducibility, as well as bioengineering electives from two or more of the four technology themes. With our record of successful junior faculty career development, we include seven outstanding and diverse new junior engineering faculty recruited since 2017, including one who has a joint clinical appointment in Cardiovascular Medicine. They will co-mentor trainees in new areas including biophotonics, medical imaging, precision biomaterials, pulmonary arterial hypertension, heart valve disease, and neurovascular injury. All faculty will receive mentorship training, and program progress and outcomes will be assessed by two advisory committees and trainee surveys. The outcome will be scientists who use integrative, technology-driven approaches to advance cardiovascular science and healthcare.

NIH Research Projects · FY 2026 · 2022-06

PROJECT SUMMARY Periodontitis and oral disease are widespread with major and negative impacts on quality of life. Radiography is the standard of care in imaging but is limited to assessment of hard tissue. In the last three years, we have shown that ultrasound imaging offers significant advantages to oral health including non-invasive and real- time assessment of the periodontal probing depths, cementoenamel junction, gingival thickness, gingival perfusion/hypoxia, and clinical attachment loss. However, further clinical work in this field is limited by the large size of the ultrasound transducers—they are simply too large to access the posterior teeth. While smaller transducers exist, they cannot operate at the high frequency (>40 MHz) needed to image the small feature sizes involved in oral health. Therefore, we have established a three-way academic-industrial partnership to refine and finalize these devices for oral health. Dr. Jokerst at UCSD serves as PI and pioneered the use of photoacoustic imaging in oral health. VisualSonics Corp. is our industrial partner—Dr. Jokerst’s preliminary data was collected on VisualSonics equipment, and this company has a 20-year track record in developing high-frequency transducers including recent 510k-approved systems for human use. The clinical partner is Dr. Casey Chen who is Chair of Periodontology at USC and who will validate the system with human subjects. Aim 1 of the work will build and validate a small hockey stick-style transducer. While this design is already common, hockey stick transducers above 20 MHz are not available. Aim 2 will integrate diode lasers into the system for photoacoustic imaging to complement ultrasound. Aim 3 will develop image-processing algorithms to automatically export metrics of oral health such as clinical attachment loss and probing depth. Such automated image-processing is critical to broad clinical acceptance. Aim 4 will validate this device in healthy and diseased human subjects with comparisons to clinical gold standards. The significance of this work is based on the widespread prevalence of periodontal disease and the remarkable new insight that acoustic imaging offers in diagnosis and treatment planning. The innovative outcomes include non-invasive charting, direct measurements of the cementoenamel junction, noninvasive biotyping, and 3D maps of inflammation near implants. The work is feasible because of the track record of all three partners as well as their history of collaboration. This is a good investment for NIH because there is no miniaturized and high-frequency (>40 MHz) ultrasound transducer available despite the dramatic improvement in spatial resolution that high frequency offers. The proposal offers deliverables at all ranges of risk and the ultrasound transducer is highly likely to succeed with implications well beyond oral health: Applications in endoscopy, head and neck diseases, as well as transrectal/transvaginal imaging are obvious.

NIH Research Projects · FY 2025 · 2022-06

Project Summary The overarching goal of this study is to evaluate a high-volume, low-threshold, naloxone-on-release program serving individuals being released from the Los Angeles County Jail system. Opioid-related overdose death is the single largest cause of accidental death in the United States. Individuals being released from incarceration are at particular risk, with some studies showing their risk of death in the weeks immediately after release is as much as 129 times that of the general population. One intervention demonstrated to reduce opioid-related deaths is training opioid users and those in their immediate social circles to recognize overdose and to respond by using naloxone, an opioid antagonist which effectively ‘reverses’ overdose. Overdose Education and Naloxone Distribution (OEND) programs are now present in almost every state. However, access to OEND programs has not been equitable, with African American and Latinx people who use opioids being less likely to access OEND, a particular concern given opioid-related overdose mortality has increased 114% among Black and 97% among Latinx populations over the last 5 years compared to 32% among Whites. One recent innovation, ‘naloxone-on-release’, aims to address the particularly high rate of overdoses experienced by individuals being released from incarceration. In addition, naloxone-on-release has the potential to reach populations underserved by traditional OEND programs given the over-representation of African American and Latinx people in incarcerated populations nationwide. At least 28 pilot or early stage naloxone-on-release programs currently exist in the US, however to date the literature on these programs is largely limited to descriptions of feasibility and logistical issues. A single paper describes the efficacy of a national-level program in Scotland, which, encouragingly, saw a 36% drop in the proportion of overdose deaths among releasees in the four weeks following release. In January 2020 the Los Angeles Sheriff’s Department implemented a naloxone-on-release program, in which all inmates being released from the LA County Jail system are exposed to a video training on overdose recognition and response and are able to take as many doses of naloxone as they wish from a no-cost vending machine at the point of release. 31,352 doses of naloxone were distributed by the program in 2020, almost twice as much as every other OEND program in Los Angeles combined, and making it by far the largest such program in the world (the Scottish program described above distributed 2,273 doses over 3 years). We will use an innovative mixed-methods design to capitalize on this timely opportunity, and examine whether the naloxone-on-release program is serving those most at risk, whether the program reaches previously underserved populations, how the program impacts the communities to which releasees return, and whether the program reduces deaths among releasees and in the communities to which they return.

NIH Research Projects · FY 2026 · 2022-06

Mild traumatic brain injury (mTBI) is a major public health problem in the United States. Data from the Adolescent Brain Cognitive Development (ABCD) study afford our team an opportunity to significantly advance the study of mTBI-associated behavioral, psychiatric, and neurocognitive problems which are very controversial. We shall analyze biopsychosocial data generated since 2016 from this ten-year prospective longitudinal 21-site national study of an enrolled cohort of over 11,000 nine/ten-year old children who have been subsequently evaluated annually. The study design permits a rare analysis of predictive factors and mechanisms of post-injury behavioral, psychiatric, and neurocognitive outcomes by examining child and family variables collected pre-injury and post-injury in the 237 children who have so far suffered a mTBI in the years subsequent to enrollment. The mTBI group will be compared with two groups of children 1) with a post-enrollment accidental bone fracture (orthopedic injury; OI); and 2) a lifetime “no injury” (NI) group. Additional children who have had a mTBI will be identified and will be compared with OI and NI controls in the first month of the study, and at the end of year 2 and middle of year 4 of the five-year study. There are three unique aspects of the proposed study. 1) Pre-injury and post-injury sequential structural and functional neuroimaging data facilitate predictive and mediation analyses of behavioral, psychiatric, and neurocognitive outcomes using individual pre- versus post-injury changes and group differences in brain maturation trajectories. 2) Genetic data permit predictive and moderation analyses of outcomes using a novel systems biology approach not based on candidate genes. 3) The proposed study evaluates multiple neurocognitive domains before and after mTBI. The study will examine 3 major hypotheses: (1) Change in behavioral measures and changes in neurocognitive function will be of greater magnitude, and new-onset psychiatric disorders will occur at a significantly higher rate, in children with mTBI compared with children with OI and NI. (2) Behavioral changes, new-onset psychiatric disorders, and neurocognitive function changes in children will be predicted by pre-injury child variables (sex, adaptive function, academic and cognitive function, lifetime psychiatric disorders, behavioral ratings, brain structure and functional MRI measures, and genetic factors), and pre-injury family variables (socioeconomic status, family function, family psychiatric history) in children with mTBI, OI, and NI. (3) The occurrence and pattern of behavioral changes, new-onset psychiatric disorders, and neurocognitive function changes will be mediated by child brain variables (trajectory of brain maturation), post-injury family variables (functioning and stressors), and injury variables (age at injury, time-since-injury, severity, presence of a brain lesion, and extent of diffuse axonal injury) and moderated by child gene structure (genetic factors), in children with mTBI, OI, and NI.

NIH Research Projects · FY 2026 · 2022-06

SUMMARY This project will constitute human research characterizing the microbiome and endocannabinoid system (ECS) in people with HIV (PWH) and how they relate to neuroinflammation and blood-brain barrier (BBB) function. Based on exciting new preliminary findings described here, we propose that alterations in the gut microbiota (dysbiosis) and impaired gut barrier integrity (leaky gut) are mediators between the ECS and neuroinflammation and BBB dysfunction in HIV. Our major goals are to (1) characterize the gut microbiota and ECS in response to exogenous cannabinoid exposure in both PWH and people without HIV (PWoH); (2) characterize patterns of HIV-associated inflammation (innate, adaptive, T-cell, B-cell) in blood and cerebrospinal fluid (CSF) in response to controlled cannabis exposure; (3) assess effects of cannabinoid exposure on these patterns and how they are mediated through changes in the ECS, gut microbiota and gut barrier function. We will perform a clinical trial of 50 PWH and 50 PWoH exposed in a randomized, cross-over fashion to 14 days each of oral THC and CBD to determine if treatment with either phytocannabinoid reduces inflammation and improves gut function. The experimental approach will use fecal shogun metagenomic sequencing to characterize the gut microbiome, with particular attention to aerotolerant bacteria, pro-inflammatory species, Prevotella spp., Bifidobacterium and Bacteroides spp. and butyrate-producing bacteria. We will evaluate how the microbiota and leaky gut relate to neuroinflammation and impaired BBB function, the latter potentially leading to increased CNS exposure to microbially-produced pro-inflammatory ligands. The rationale for the study is that virologic suppression on antiretroviral therapy (ART) does not normalize gut lymphoid tissue CD4+ T cell depletion, leaky gut, dysbiosis, chronic gut inflammation, and microbial antigen translocation (MAT). These alterations ultimately drive systemic and CNS inflammation. Compromised gut barrier function due to altered tight junctions, apoptosis and reduced epithelial cell proliferation and repair render PWH susceptible to increased tissue exposure to pro-inflammatory ligands produced by gut microbiota and are important in HIV neuropathogenesis. Of particular relevance here are recent findings that the ECS in the large intestine interacts with the gut microbiota to regulate epithelial barrier permeability. Thus constituents of cannabis, acting through the gut EC system, may be therapeutic, and the existing literature suggests that the two principal constituents of cannabis, Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), have differential effects on the ECS.

NIH Research Projects · FY 2026 · 2022-06

PROJECT SUMMARY Systemic immune activation in people living with HIV has been hypothesized to account for higher incidence of chronic inflammatory diseases, including HIV-associated neurocognitive disorders (HAND). Acute HIV infection in the CNS is thought to initiate a cascade of pro-inflammatory events that result in inflammation-induced neuronal injury and associated neurocognitive disorders that are evident even in the present combination antiretroviral therapy (cART) era. The use of psychostimulants (such as cocaine and methamphetamine) and alcohol has been shown to disrupt BBB integrity. Disrupted BBB may increase immune cell infiltrating into the CNS and promote glial activation, increased inflammation and neurotoxicity. Interestingly, increased permeability of BBB has been implicated in the progression of HIV neurological dysfunction. Thus, the combined effect of cocaine usage and HIV infection can cause an additive effect on BBB disruption and further impact HIV-related neurocognitive impairments. However, not much genome-wide molecular level study has been done in understanding BBB integrity in substance use disorder and in HIV infection/HAND. The proposed study will address this important question. Our central hypothesis is that cocaine misuse exacerbates HIV pathogenesis in the CNS by disrupting blood-brain barrier and dysregulating the glial population in the brain. Our overall objective is to exploit cell type specific transcriptomic information at the single nuclei level from patient brain samples to characterize the effects of cocaine use disorder on CNS neuronal and glial cells, HIV infection and HANDs. We will characterize single nuclei gene expression and identify dysregulated gene regulatory networks in each of the neuronal and glial populations associated with cocaine misuse in HIV infected individuals and/or with HANDs. We will also perform computational analysis to identify neuronal and glial cell regulatory networks altered by cocaine misuse. In the validation and functional characterization component, we will characterize top genes in 3D brain organoid model and will characterize with CRISPR knockout and overexpression of the gene. Successful completion of these aims will have significant research and clinical impact by 1) elucidating how cocaine misuse alters HIV/HAND pathogenesis in the CNS, and 2) discovering candidate molecules to regulate HIV infection or persistence in the CNS in the context of cocaine misuse.

NIH Research Projects · FY 2025 · 2022-06

Project Summary Cardiovascular catheterization is a minimally-invasive approach to measure hemodynamics and treat abnormalities, such as vascular stenosis. Conventionally, X-ray fluoroscopy guides catheterizations, but it uses ionizing radiation and suffers from poor soft tissue contrast even with the use of exogenous contrast agents. This is problematic in children as they are particularly susceptible to radiation, often require repeat assessments, and can have complex anatomy that is difficult to navigate. MRI guidance provides a non- ionizing alternative that can improve soft tissue contrast and enhance evaluations. In addition to guiding diagnostic catheterization, first-in-human studies 15 years ago demonstrated that MRI could guide cardiac interventions such as coarctation angioplasty. However, clinical adoption since then has been limited by 1) few MRI-safe interventional devices and 2) the relatively poor real-time MRI image quality available during procedures. The number of MRI-safe devices is increasing, and low-field MRI has emerged as a new way to significantly reduce device heating. Yet, poor real-time image quality remains a significant barrier. Despite parallel imaging and accelerated image reconstructions, image quality is constrained by the limited set of MRI samples available for image reconstruction in a single-shot, real-time acquisition. The solution: This proposal aims to leverage multi-beat information to improve real-time MRI image quality during pediatric interventions. The goal is to improve image quality by increasing data available for image reconstruction and improve device visualization by highlighting motion between beats. The central hypothesis is that, in the interventional setting, multi-beat information will improve real-time MRI image quality and device visualization, leading to improved operator confidence and performance. To test this hypothesis, multi-beat’s impact on interventional image quality (Aim 1), impact on device visualization (Aim 2), and clinical utility in pediatric patients (Aim 3) are evaluated. The proposal is supported by a team that includes pediatric cardiologists at the forefront of MRI-guided interventions and prior research experience developing a closed- loop MRI data collection technique which robustly identifies similar heartbeats. The platform was originally designed for a different application – improving non-interventional MRI imaging of adults with arrythmia. Here, it is adapted to explore a new imaging paradigm (interventional imaging) in a new patient population (pediatric patients) for the PI. The work is expected to establish a new approach for real-time MRI-guided cardiovascular interventions by addressing the areas that currently limit image guided confidence: poor anatomic and device visualization. Success would not only improve MRI guidance of cardiovascular interventions in children but also create new opportunities for MRI guidance of cardiovascular and non-cardiovascular (biopsy, drainage, thermal therapy) procedures for adults.

NIH Research Projects · FY 2025 · 2022-06

Current treatment planning for brachytherapy of cervical cancer is performed with manual techniques that are both time-consuming and subjective. Manual treatment planning takes 95 minutes on average and occurs while patients are sedated, and the quality of the treatments is highly dependent on the expertise of the physician. Unfortunately, the resource intensiveness and need for specialized expertise are barriers to implementation of brachytherapy, and as a result many centers are not offering this essential treatment for cervical cancer. Alarmingly, this rapid decline in brachytherapy utilization has been linked to 12% reductions in patient survival. To overcome the barriers to delivering highly effective brachytherapy, there is a critical need for tools that improve the efficiency and reduce the complexity of treatment planning for each patient. My long- term goal is to become an independent investigator focused on automating brachytherapy cancer treatment with machine learning, producing button-click solutions that will significantly upgrade the quality of brachytherapy and combat declining utilization. I have significant experience in modeling, image processing and computer programming and I want to build on this skillset with a training program that will prepare me for independence. I have assembled an exceptional mentorship team, which includes expertise in machine learning, clinical trials, implementation science and statistics. We formed a training plan to gain expertise in (1) deep learning, (2) advanced statistical analysis, (3) design of clinical trials and implementation of technology and (4) research career development. The research goal of this proposal is to develop a tool for fully automated cervical brachytherapy treatment planning, which uses machine learning models to make predictions for new patients. The central hypothesis is that automated planning using machine learning will generate non-inferior or even superior plans in significantly reduced treatment planning time. This hypothesis will be tested with the following specific aims: (1) Develop machine learning models, which use labelled patient images to predict radiation dose; (2) Develop and evaluate efficacy of a pipeline for automated brachytherapy planning; and (3) Prospectively measure the efficiency and clinical impact of automated brachytherapy planning. For Aim 1, convolutional neural networks will be developed to predict 3D radiation dose from imaging. Aim 2 will convert predicted doses into deliverable treatment plans using gradient-descent optimization to determine optimal treatment parameters. Aim 3 will provide an end-to-end validation of the automated planning by testing it in real-time clinical workflow. This work is innovative because it presents the first clinical validation of an automated treatment planning system for brachytherapy of cervical cancer. The proposed research is significant because it will revolutionize the current brachytherapy paradigm by applying machine learning to automate and standardize time-consuming, manual processes. This work is a key step towards my future R01 submission on multi-institutional implementation of automated cervical brachytherapy.

NIH Research Projects · FY 2025 · 2022-06

Summary Despite recent advances in tissue engineering and regenerative medicine, heart failure (HF) following myocardial infarction (MI) continues to be the leading cause of death in the U.S., and the rest of the western world. One of our goals is the development of new, minimally invasive tissue-engineered therapies for the treatment of MI. While cell therapies have been extensively studied for the treatment of MI and HF, meta-analyses of initial cell therapy trials suggest only a modest effect on cardiac function. Injectable biomaterials that stimulate endogenous repair are an attractive, potentially more effective alternative since therapies could still be delivered minimally invasively via catheter, yet could be off the shelf and have significantly reduced costs and complications compared to cell products. The PI’s lab developed the first cardiac specific injectable hydrogel, a myocardial matrix hydrogel, which is derived from decellularized porcine myocardial extracellular matrix (ECM) and is deliverable via a transendocardial injection catheter. This material is liquid at room temperature and forms a porous and fibrous scaffold upon injection, which we have shown promotes pro-remodeling immune cell polarization, other endogenous cell infiltration and cardiac repair in subacute and chronic MI models. This initial work led to a successful Phase I clinical trial in post-MI patients. However, this approach is not amenable to treating acute MI patients because of safety issues related to transendocardial injections. Therefore, significant damage and remodeling of the heart will occur before a patient is even eligible for this therapy. In contrast to transendocardial delivery, intracoronary infusion can be performed in acute MI patients as interventional cardiologists are already performing a balloon angioplasty. We therefore recently developed a new infusible form of ECM (iECM) that can be delivered via intracoronary infusion to coat and fill gaps of damaged vasculature to heal the tissue. We have already shown this is effective when delivered immediately post-reperfusion in a rat acute MI model and in a pilot pig study. In acute MI, we hypothesize that iECM promotes endothelial cell survival and polarization of infiltrating immune cells to a pro-remodeling phenotype, which secondarily along with an already demonstrated reduction in vascular permeability results in improved cardiomyocyte survival. Our preliminary results provide strong support for the use of our new iECM technology for treating acute MI. In this proposal, we will better understand the immunomodulatory and regenerative potential of our iECM technology and perform translational studies with the goal of developing a novel therapy for acute MI.

NIH Research Projects · FY 2025 · 2022-06

PROJECT SUMMARY Congenital ataxias generally result from dysfunctions and malformations of the cerebellum, particularly the medial vermis. These disorders may result from the lack of proper developmental signaling cascades which dictate the proliferation and formation of neurons. Primary cilia provide a hub for various developmental signaling proteins such as SHH or WNT. Dysfunction in ciliary proteins leads to rare genetic disorders affecting human development in the nervous system, optical system, and liver, kidney, and skeletal systems. Patients with ciliopathies like Joubert Syndrome and related disorders display cerebellar vermis hypoplasia, thickened superior cerebellar peduncles, and a deepened interpeduncular fossa. Components of the cytoskeleton, such as actin and microtubules, play a vital role in ciliogenesis and the maintenance of existing ciliary components and supporting scaffold. Although many cilia-related genes have been found to be causal for these disorders, cytoskeletal regulators of the formin family and their relationship with cilia has not yet been fully defined, nor have these molecules been previously associated with abnormal brain development. Our lab uses a forward genetic approach to identify pathways critical to cerebellar development and degeneration of neurons in this brain region. Through a chemical mutagenesis screening, we discovered an ataxic mouse mutant with phenotypes similar to those observed in some ciliopathies: cerebellar hippocampal hypoplasia, abnormal foliation, cerebellar elongation along the anterior-posterior axis, as well as the failure of the superior cerebellar peduncle to decussate. By positional cloning, we identified a mutation at a splice acceptor in Fmnl2, leading to exon skipping in Fmnl2 transcripts. Interestingly, levels of Fmnl2 transcripts in the brain of mutant mice are unchanged compared to WT, but protein levels are reduced, suggesting that the in-frame deletion encoded by this exon are necessary for stability of this protein. FMNL2 is an autoinhibited cytoskeletal effector that has been previously shown to drive actin polymerization at filopodia and lamellipodia tips of cultured cells. Although other proteins in this family have shown to bind and regulate microtubules, actin, and influence cilia formation, whether this protein functions in microtubules and actin during brain development is unknown. Using this novel mouse model, I will investigate the role of FMNL2 in actin and microtubule stabilization and determine how the hypomorphic loss of this protein may impact ciliogenesis and cilia maintenance. These studies will enlighten our understanding of cerebellar malformations and impact our understanding of the mechanisms underlying the role of microtubules and actin in human ciliopathies.

NIH Research Projects · FY 2025 · 2022-06

Abstract Climate change is a well-documented reality that is impacting planet earth and its inhabitants. The health impacts of climate change have been studied in terms of heat wave, air pollution, spread of vectors of infectious diseases, and extreme weather events of flooding, drought, wildfires, as well as mental illnesses. One of the regions that will be impacted most from climate change is the Middle East and North Africa (MENA). Yet, there is very limited understanding of the human health impacts, the possible policies and interventions to address them, and most importantly limited capacity in research of such policies and interventions. Through this proposal we will establish the GeoHealth Hub for Climate Change Health Impacts in MENA through its two components: The U01 research component (1/2 GeoHealth Hub for Climate Change and Health in the Middle East and North Africa- Jordan) and the U2R training component. The research and training will take place in Jordan, Lebanon, and Morocco. The climate relevant areas of research will focus on heat waves, precipitation and water quality, air pollution, and desert dust pollution. Cost-effectiveness analyses of environmental health policies will be determined to quantify health benefits from interventions through economic models and then informing local governments through dissemination and implementation science. These will be linked to the U2R GeoHealth Hub training application titled “2/2 GeoHealth Hub for Climate Change and Health in the Middle East and North Africa-U.S. The training program will focus on creating a cadre of local experts in one or more of the areas of environmental health in the scope of the U01. The U2R training will build on the ongoing R25 training grant between the two collaborating academic institutions in Jordan (Jordan University of Science and Technology-JUST) and the U.S. (University of California San Diego) (2R25TW010026-06A1). We have assembled an exceptional team of collaborators from the top institutions led by the University of California San Diego and with UC Berkeley, and Harvard University, as well as support of the U.S. CDC. This will be complemented by partnership in the MENA represented by the Jordan University of Science and Technology in Jordan, University of Balamand in Lebanon, Mohamed VI University for Health Sciences in Morocco, and the WHO Regional Eastern Mediterranean Center for Environmental Health Action located in Amman, Jordan. The training program will include short term didactics in the form of summer courses, workshops, U.S visits, and virtual webinars to build individual capacity building. We will build institutional capacity through the addition of tracks in environmental health to existing masters and PhD programs. We will also have mentored one-on-one research training on work related to the U01 aims. We will also aim to influence overall awareness about climate change health impacts among the general health and policy professional community through an annual regional conference to showcase the hub. This will be a sustainable state-of-art hub to inform policy makers about the health risks of climate change and the first of its kind to fill in a major gap in this region.

NIH Research Projects · FY 2026 · 2022-06

Generating adaptive body movements is a fundamental function of the brain. The primary motor cortex (M1) is a central locus for motor learning and execution. M1 receives long-range inputs from several brain areas and processes this information through local recurrent connections. However, how various inputs and local connections work together to shape M1 activity is unknown. In this proposal, we will investigate the contributions of long-range inputs and local connections to M1 activity and how they are shaped during motor learning. We will do this using a well-established motor learning paradigm in mice. Our central hypothesis is that the functional properties of individual M1 neurons are defined by their responses to long-range inputs and local neurons. We further hypothesize that learning induces a reorganization of the responses of M1 neurons to specific inputs. This proposal will investigate the nature of the information that M1 receives from various upstream regions, the unique activity patterns of M1 neurons that receive these inputs, and how the local M1 network contributes to their activity patterns.

NIH Research Projects · FY 2026 · 2022-06

Project Summary Amyloid accumulation in the brain is a universal feature of Alzheimer’s disease (AD) and many other related dementias and precedes clinical symptoms by several years. Methods for antemortem detection of amyloid species may, therefore, aid in diagnosing and monitoring neurodegeneration, providing critical information that can be used to devise a proper plan for patient management. While a number of clinical tools for detecting amyloid in the brain or cerebral spinal fluid have been developed to help diagnose AD, methods to differentiate AD from non-AD neuropathology in living patients are limited. We have recently developed two new families of fluorescent probes that can selectively detect aggregated forms of tau or alpha-synuclein, which could address an unmet need by extending the available toolbox for aiding in detection of amyloid or amyloid-like aggregates associated with non-AD diseases such as Frontotemporal Dementia (FTD), Parkinson’s disease (PD), and other tauopathies and synucleinopathies. The proposed research seeks to uncover new and reliable design principles for developing such selective amyloid-responsive probes and will seek to evaluate their utility for detection of amyloid species in emerging platforms for antemortem diagnostics. The Specific Aims of this proposal are to: 1) Develop fluorescent probes that exhibit selective enhancement of fluorescence upon binding to aggregated alpha-synuclein or tau versus ABeta in solution and in tissue; 2) Develop a method to characterize the distribution of aggregates of amyloidogenic proteins in biofluids; and 3) Evaluate whether selective amyloid-responsive fluorescent probes can be used to image specific amyloid deposits in the retina.

NIH Research Projects · FY 2026 · 2022-06

PROJECT SUMMARY/ABSTRACT Alzheimer’s disease (AD) is costly and burdensome. As the US population ages, AD’s public health impact continues to grow. NIH and Alzheimer’s Association consensus statements indicate that understanding early phases of disease progression—such as mild cognitive impairment (MCI)—beginning in middle age is key to slowing dementia onset. Identifying at-risk individuals early is also estimated to result in massive savings. Despite the protracted progression of AD brain pathology, little is known about its temporal course from middle to older age, particularly for neuroimaging indices. The Vietnam Era Twin Study of Aging (VETSA) focuses on early identification of risk for MCI/AD and AD-related brain changes beginning when subjects were in their 50s. The proposed VETSA MRI wave 4 project, with a mean age of 74 (67-78), occurs during a time of increased incident MCI/AD. That, in combination with our longitudinal data, allows for improved ability to determine neuroimaging correlates, trajectories, and their predictors. Continued data collection will allow us to examine the transition period from pre- to post-disease onset and expand on prediction from midlife for an increasing number of individuals. This project is linked to the funded general VETSA 4 grant (AG050595) which collects 10-12 hours per subject of cognitive, health/medical, psychosocial and biomarker data. In addition, we can elucidate genetic and environmental influences on these processes via combined twin and genome-wide genotyping/polygenic score data. We also capitalize on early (age 20) cognitive data, a unique feature enabling us to differentiate cognitive decline from longstanding differences. We request funds to cover MRI acquisition, processing, and analysis (n=500), leveraging associated ongoing work in the general VETSA 4 grant. Aims are: 1) Develop, validate, and characterize novel early brain indicators of risk for MCI/AD. We will develop and validate a novel AD brain signature based on diffusion MRI and show that this brain signature of adults who are only in their 50s improves prediction of progression to MCI. We also hypothesize that integrity of the locus coeruleus—the earliest brain site of tau deposition—will be another early, sensitive risk indicator. 2) Examine cerebrovascular risk factors and their relationship with cognition and AD biomarkers. Cerebrovascular disease (CVD) is the most common pathology concomitant with AD and may contribute to disease progression or be an independent source of brain and cognitive decline. We particularly focus on CVD markers of white matter hyperintensities and arterial spin labeling (ASL) perfusion. 3) Quantify the magnitude of neurodegeneration from midlife to early old age and its underlying genetic and environmental influences. We will examine genetic influences on longitudinal change in macro- and micro-structural brain measures. Our approach includes identifying mediating/moderating effects of risk factors across the lifespan and leveraging our twin and genome-wide genotype data. Covering ~18 years, this project will be a resource for advancing knowledge about early identification of risk for MCI/AD, with potential for a profound public health impact.

NIH Research Projects · FY 2025 · 2022-06

PROJECT SUMMARY This proposed project aims to develop a wearable ultrasonic patch for automatic, continuous, and noninvasive central blood pressure monitoring. Hypertension is a “silent killer” since it gradually induces a series of cardiovascular diseases, usually without any obvious symptoms. Compared with brachial blood pressure acquired by the cuff, blood pressure at central locations has been proven to be more valuable for predicting future cardiovascular events and disease risks. Thus, it is essential to measure central blood pressure regularly to maximize the blood pressure management outcome. This research is distinct from all other existing methods for central blood pressure measurements that have a series of different technical challenges, such as the use of invasive procedures, insufficient accuracy, and significant dependence on the operator’s skills. In 2018, the PI’s group invented the first wearable ultrasonic device for central blood pressure recording, supported by an R21 grant from NIH. However, this device still needs cables for power and data transfer, manual processing of the data, and a low signal-to-noise ratio. In this proposed project, we will demonstrate a wearable ultrasonic transducer array integrated with miniaturized wireless control electronics and automatic data processing algorithms. The integrated control electronics will eliminate the bulky setup and connecting wires. The phased-array beamforming will focus and steer the ultrasound beam to search the blood vessels and improve the signal-to-noise ratio and the spatial resolution. All data acquired by the wearable ultrasonic device will be wirelessly transmitted to a terminal receiver (e.g., a smartphone), where a deep learning based algorithm is running for further data processing. The customized algorithm will automatically localize the targeted artery and track both the anterior and posterior walls of the vessel without the supervision of human operators. Thereby, the operator dependence in conventional ultrasound systems will be eliminated, and device usability can be much improved. Finally, the proposed entire system will be validated on patients against arterial catheterization, the current gold standard for central blood pressure monitoring in clinical settings. If successful, this proposed study will provide patients with a device that can access their central blood pressure automatically, continuously, and noninvasively. Using a stretchable platform that matches the softness of the human skin will make a key difference in patient acceptance and monitoring outcomes. The ease of measurements enabled by the automatic algorithm can significantly help high-throughput screening of central blood pressure in the general population and guide the development of antihypertensive drugs, which can eventually translate to a significant reduction in blood pressure associated mortality and healthcare costs.

NIH Research Projects · FY 2026 · 2022-05

ABSTRACT The opioid crisis has become a national epidemic and the statistics are startling. In the past decade there has been a sharp increase in heroin use, opiate prescriptions and fentanyl abuse. Overdose deaths have doubled nationally since 2000 and in 2015, and more than 33,000 deaths were attributable to overdose from opioids. In addition, there has been a major increase between 1998 and 2011 in the number of opioid-dependent pregnant women, such as with methadone dependency. Although opioids have been well studied in general, the epidemic of opioid abuse, especially in pregnant women, has unmasked how little we know about the effect of methadone on fetal brain development. In the past several years, we have taken advantage of a newer technology, the 3D- brain organoids, that facilitated enormously the investigation of early human brain development. This has provided us with an unprecedented opportunity to investigate the cellular and molecular mechanisms underlying the effect of opioids on early brain development. Using such methods, we have been able to produce exciting preliminary data showing that methadone decreases synaptic transmission and possibly affects synaptic plasticity. Based on our recent results, we have posed the following overall hypothesis: Opioid exposure leads to abnormal synaptogenesis and impaired synaptic transmission during fetal brain development. In order to address this hypothesis, we have formulated the following Specific Aims: Specific Aim 1: To determine the effect of methadone on neural network activity during development in human cortical organoids. We will use multi- electrode array recordings to explore how methadone modifies the neural network activity. Specific Aim 2: To determine the effect of methadone on cellular electrophysiological properties and synaptic function and structure during development in human cortical organoids. We will investigate AP firing properties, synaptic currents, and Na+ and K+ currents in neurons and dissect the pre- and postsynaptic mechanisms using patch-clamp, molecular and imaging techniques. Specific Aim 3: To dissect the mechanisms of the methadone-induced changes in synaptogenesis and synaptic transmission in human cortical organoids. As thrombospondins 1,2 (TSP1,2), astrocyte-secreted glycoproteins, play a role in neurite outgrowth, dendritic spine and synapse formation, we will study the effect of methadone on TSPs to obtain an understanding of the molecular pathobiology of methadone’s effect on the human fetal brain. Our studies in this application are novel and unique and address the important problem of human brain maldevelopment under the influence of methadone in pregnant women. With an understanding of the mechanisms involved in methadone effect, we believe that we can develop novel therapeutic targets to mitigate the effect of methadone on brain development in early life.

NIH Research Projects · FY 2026 · 2022-05

Abstract By 2060, the CDC projects that the Latino population will experience the largest increase in Alzheimer’s disease and related dementia (ADRD) cases of all US ethnic/racial groups. The main explanation for high Latino ADRD is attributed largely to early and excess cardiovascular disease (CVD) morbidity contributing to disparately high ADRD. CVD risk factors emerge early in midlife among Latinos, thereby increasing exposures to exquisitely sensitive and highly vascularized brain tissue. Yet, to-date there has not been any study of Latinos with sufficiently deep CVD phenotyping and genotyping to adequately address this significant public health question. This scientific knowledge gap is a significant impediment to the field and public health given rapid Latino population growth projections, particularly for older adults. The Study of Latinos-Investigation of Neurocognitive Aging-Alzheimer’s Disease (SOL-INCA-AD) will augment the ongoing large, representative and unique cohort with 10-years of advanced biomarkers of Alzheimer's disease to understand cognitive aging and impairment amongst diverse Latinos. Together with 10-years of cognitive measures, MRI, deep CVD phenotyping, genomics and rich sociocultural data, SOL-INCA-AD is a high priority study that will fill major scientific knowledge gaps that form barriers to progress for Latino ADRD research.

NIH Research Projects · FY 2025 · 2022-05

Project Summary / Abstract Sepsis, Septic Shock, Acute Kidney Injury (AKI), acute respiratory distress syndrome (ARDS) and respiratory failure are among the top causes of hospital mortality, morbidity, and an increase in duration and cost of hospitalization. Successful prevention and management of these conditions rely on the ability of clinicians to estimate the risk, and ideally, to anticipate and prevent these events. Acute care settings and in particular intensive care units (ICUs) provide an environment where an immense amount of data is acquired, and it is expected that with the advent of wearables and biometric patches even more data will be available in such settings. But at present, very little of these data are used effectively to prognosticate, and the existing predictive analytics risk scores suffer from lack of generalizability across institutions and performance degradation within the same institution over time. The PIs on this proposal recently demonstrated that a Deep Learning-based algorithm can reliably predict new sepsis cases in the emergency departments, general hospital wards, and ICUs by as much as 4-6 hours in advance and an area under the curve (ROC) of 0.85-0.90. Furthermore, through a 2-year pilot study funded via Biomedical Advanced Research and Development Authority (BARDA), we recently joined forces in a multicenter academic consortium to retrospectively validate this algorithm at each site. Our collaboration has resulted in a multi-center longitudinal EHR dataset of critically ill patients and has generated several important questions and findings related to design of portable and generalizable predictive analytics algorithms that are robust to problems arising from gaps, errors, and biases in electronic health records (EHRs) due to workflow-related factors (e.g. staffing-level), and heterogeneity of patient populations and measurement devices. We propose to significantly expand our prior work by designing new deep learning architectures that are robust to data missingness and biases introduced through the variability in process of care, 2) development of new learning methodologies to improve generalizability of the proposed models under data/population drifts (aka distributional changes), 3) enhanced metadata design to assist in quantifying `conditions for use' of such algorithms via algorithmic controls, and 4) HL7 and FHIR-based prospective implementation and testing of these methodologies to provide real-world clinical evidence for the effectiveness of the proposed approaches. Ultimately, these novel methodologies and tools will enhance our ability to use EHR and other types of continuously measured longitudinal data to predict adverse events, assess patients' response to therapy, and optimize and personalize care at the beside.

NIH Research Projects · FY 2026 · 2022-05

PROJECT SUMMARY/ABSTRACT This proposal outlines a 5-year research and career development plan for Dr. Gabriel Wardi, an emergency medicine intensivist and assistant professor at UCSD. The major objective of his research is the effective implementation of deep-learning algorithms to clinical practice to improve care of sepsis patients. This K23 proposal outlines and provides support for his career development plan, specifically focusing on (1) the ability to design meaningful sepsis studies and necessary statistical training, (2) strong understanding of machine- learning approaches, and (3) a focus on implementation science to improve care of sepsis patients with novel deep-learning algorithms. Dr. Wardi has assembled a diverse team of collaborative experts to support his career development and mentor him consisting of Dr. Atul Malhotra, an internationally recognized expert in critical care physiology and respiratory failure along with Dr. Shamim Nemati, a machine-learning expert with a strong focus in prediction of sepsis in real-time. Additionally, his training team includes experts in implementation science from the Dissemination and Implementation Science Center (DISC) at UCSD as well as an expert in clinical trial design and biostatistics (Dr. Sonia Jain). Despite decades of research, sepsis remains a major public health challenge. Current approaches to sepsis care emphasize “one-size fits all” bundles that may result in patient harm in certain subgroups. Newer approaches to data analysis, using multiple layers of non-linear arithmetic operations now allow for clustering of sepsis patients into novel clinical phenotypes that may provide for more personalized care. The PI will evaluate potential phenotypes of sepsis not present on admission (NPOA) in Aim 1. Prior investigations into phenotyping have been developed and validated in patients present in the emergency department. Patients with sepsis NPOA have high mortality and better quantification of phenotypes may help improve care by identifying novel groups. Dr. Wardi seeks to evaluate 2 inter-related hypotheses in this aim: one is that phenotypes may represent disease trajectories that are modifiable by accepted therapies (e.g. time to, and quantity of fluid resuscitation). The second is that novel phenotypes exist in the inpatient setting. In his second aim, Dr. Wardi seeks to determine clinical mechanisms of 30-day readmissions in sepsis patients through a variety of approaches, including identification of novel clusters of sepsis patients at discharge and use of natural language processing of a large data set to identify actionable reasons for readmissions. Finally, he seeks to determine if the application of a wearable patch to sepsis patients discharged to a long-term acute care hospital when combined with a machine-learning algorithm may reduce unanticipated 30-day sepsis readmissions. This research and career development plan affords Dr. Wardi an impressive foundation to develop into a prominent clinician-scientist working to improve care by developing and implementing novel approaches to detection and classification of sepsis patients. Dr. Wardi is fully committed to improving the care of sepsis patients by embracing innovative strategies.

NIH Research Projects · FY 2026 · 2022-05

PROJECT SUMMARY/ABSTRACT The ketogenic diet has been proposed as a treatment for Alzheimer’s disease (AD), a disease marked by the aggregation and inter-neuronal spreading of the protein tau. Although preclinical studies and early stage clinical trials have shown promising results on improved memory in individuals with early AD, the mechanism(s) by which the ketogenic diet slows AD progression is not well understood. Such gap of knowledge prevents the development of more precise ketone-based therapies with higher efficacy and reduce side effects. The ketogenic diet might act through multiple mechanisms: for example, the main ketone body, β- hydroxybutyrate (BHB), provides an energy source and also acts as a signaling molecule. Parsing the contribution of these mechanisms will help define which components of ketogenic diet are most relevant to tauopathies. We have found that a ketone-supplemented diet significantly reduced tau spread in mice. Additionally, treatment with BHB markedly reduced tau secretion in cultured cortical neurons. The overall objectives in this application are to elucidate the cellular and molecular mechanism(s) by which BHB reduces tau spread and neurodegeneration. The central hypothesis is that BHB acts to inhibit tau spread primarily via its signaling activity, and specifically, BHB represses tau secretion from neurons and promotes its degradation through the autophagic-endolysosomal flux. The rationale for this project is that a determination of the preclinical therapeutic efficacy and mechanism(s) of BHB on tau spread will likely lead to better targeted and more effective ketone-based pharmacological therapies for AD and other tauopathies. The central hypothesis will be tested by pursuing three specific aims: 1) Determine the contribution of signaling verses bioenergetic activity of BHB in reducing tau spread and improving neurodegenerative phenotypes in mice; 2) Determine the effects of BHB on the autophagy-endolysosomal pathway (ALP) in regulation of tau degradation, secretion and propagation, and 3) Determine the impact of BHB on the tau interactome in response to BHB’s signaling and bioenergetic activity, respectively. The proposed research is innovative because it tackles the unknown mechanisms underlying the effects of the ketogenic diet on tau, using a combination of pharmacology, genetics, cell biology and system biology approaches in primary and iPSC-induced neuronal culture, fly and mouse models. Results from the proposed studies will bridge the knowledge gap of how the ketone body affects tau pathogenesis and elucidate the underlying mechanisms, thus enable future development of novel treatment strategies for AD and other tauopathies.

NIH Research Projects · FY 2026 · 2022-05

PROJECT SUMMARY/ABSTRACT The overall objective of the T35 Short-Term Research In Vision & Eye health (STRIVE) Program is to develop well qualified medical students who will ultimately become ophthalmology clinician scientists to effectively contribute to translational eye and vision research. The proposed program is designed to expand the pipeline of new physician investigators in ophthalmology. The program will provide full-time support for 8-12 consecutive weeks of research and clinical training during the summer for 8 qualifying medical students per year from across the country. The program builds on the exceptional training record of faculty from the University of California San Diego School of Medicine (ranked in the top 96th percentile for NIH Training grants) in general, and the UCSD Viterbi Family Department of Ophthalmology and Shiley Eye Institute in particular. Moreover, UCSD is highly collaborative with strong programmatic support for the translation of research from bench to bedside in areas such as genetics/proteomics, clinical research, bioengineering, ophthalmic imaging and image analysis, drug delivery, and biomedical informatics. The most important aspects of this program will be hands-on research experience and development of a long-term mentoring relationship. The multi-disciplinary research training experience will also include didactic instruction appropriate to the area being studied, professional development seminars, lectures and journal clubs in various disciplines. Instruction in biostatistics, research ethics, leadership, presentation skills, and grant writing will also supplement the direct research experience. The trainees will give poster and oral presentations at a Summer Research Symposium and will work with mentors to develop their work for subsequent presentation at national conferences. The administrative structure of the training program includes Co-PIs/PDs Sally Baxter, MD, MSc and Linda Zangwill, PhD, and an Executive Committee that includes the department chair, vice chair of education, and residency program director. In addition, an External Advisory Committee consisting of experienced short-term training grant leaders will provide independent guidance. There will be a rigorous and extensive evaluation of the program. Online forums, including a website and social media outlets, will be used to facilitate continued communication between trainees, alumni, and participating faculty.

NIH Research Projects · FY 2026 · 2022-05

One in 10 Americans age 65 and older (10%) has Alzheimer’s disease (AD). Among type-2 diabetes mellitus (DM) patients, nearly 70% develop AD with aging. Numerous studies support the association between DM and AD. AD is a slowly progressive, irreversible neurodegenerative disease with a long preclinical phase lasting up to 20 years; the prevalence of AD in DM increases in later years. DM is a known risk factor for vascular disease and is associated with diffuse sclerosis in microvasculature. The relationship between these two diseases and the mechanisms that link them together are not fully understood, but slower glymphatic clearance in DM patients is expected to play a significant role. The concept of glymphatics in the brain was pioneered by Negergaard, who identified a system by which soluble proteins and metabolites are eliminated from the central nervous system via cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange in the paravascular space. Studies supporting its importance continue to be expanded upon and validated in ongoing research, primarily in rodents. Sleep and physical activity have been reported to accelerate glymphatic clearance. During sleep, a nearly 60% increase in clearance of rat brain wastes has been observed, caused by expansion and contraction of the extracellular space. Additional studies have shown that glymphatic clearance decreases with increasing age but can be increased transiently in aged mice by voluntary wheel running exercises. More recently, in humans, use of a gadolinium- based contrast agent (GBCA) via intrathecal injection allows for observation of glymphatic clearance as a tracer, albeit over a long period. However, this method is limited by its invasiveness, and by the unknown effect of the GBCA tracer on the in vivo time-course of glymphatic clearance. Physical exercise has been reported to improve clearance of brain Aβ in rats. Recent small animal studies show GBCA clearance in the interstitial space slowed by a factor of three in the hippocampus of DM rats. DM rats also showed decline in cognitive function compared to non-DM rats. Although these studies suggest that reduced glymphatic clearance is important for cognitive decline in DM rats, interpretation is limited by possible underlying changes between DM and non-DM rats, and effects of GBCA on CSF clearance. Using a novel, non-invasive, non-contrast MRI techniques we propose to study dural lymphatic clearance in DM and non-DM human brains, physical activity-induced clearance in parasagittal dura (PSD) and arachnoid granulations (AGs) fluid at meninges in humans. Our challenges include identification of PSD and AGs and measurement of subtle changes in dural lymphatic fluid clearance at meninges. To overcome these challenges, we will develop MR techniques to clarify i) the anatomy of PSD, AG, and superior sagittal sinus, ii) identify the detailed clearance pathway of dural lymphatic fluid; iii) obtain dural lymphatic fluid perfusion measures; iv) evaluate the age and exercise effects in healthy subjects; and v) compare the dural lymphatic perfusion of DM patients with age-, sex-matched healthy adults. We expect that dural lymphatic perfusion measures will be different and altered with exercise, as compared to healthy aging subjects.

NIH Research Projects · FY 2026 · 2022-05

Project Summary The goals of my research program are to elucidate fundamental mechanisms underlying synapse and axon development and maintenance. We take multi-tiered approaches to investigate these processes, primarily using C. elegans because this animal model is well suited for in vivo imaging with high cellular resolution and because mechanistic dissection is within physiological relevant contexts and coupled with functional impacts. We examine the C. elegans locomotor circuit, because we can unambiguously observe the stereotyped patterns of synapses in all developmental stages, an essential readout to assess how synapses are dynamically regulated. We have consistently developed innovative technologies enabling visualization of organelles and subcellular structures in axons and synapses for in vivo analyses of dynamic cellular processes. We were the first to visualize synapse remodeling of juvenile motor circuit in living animals, which set two decades of vibrant research that have revealed multiple pathways coordinating temporal events and spatial organization of synaptic connections. We established C. elegans axon regeneration model, and have used large-scale genetic screens to discover genes that promote or repress axon regrowth in adults. Many pathways have been found to have conserved roles in axon regeneration in other animal models. In this R35 application, we will focus on mechanisms underlying both the developmental synapse plasticity in locomotor circuit maturation and maintenance, and also neuronal stress response and axon regeneration in adults. We will investigate how neuronal activity pattern coordinates with transcriptional regulation by combining in vivo imaging of synapse and calcium with single-cell RNA sequencing analysis over the entire period of circuit remodeling. We will gain a deep understanding of molecular dynamics associated with synapse and circuit plasticity. We have long-standing interest in the multifaceted roles of the conserved MAP3K DLK proteins, which have been shown to regulate diverse cellular processes from synapse formation and remodeling to axon regeneration and neurodegeneration. We will cross-examine mechanistic conservation between C. elegans and mice. Membraneless compartments generated through protein phase separation are now widely shown to play key roles in organizing cellular activities, including axon regeneration. We will take a holistic approach to investigate protein phase separation with physiological relevant expression and contexts, and also to model how genetic mutations in human homologs may alter protein phase separation properties. Overall, the findings will advance our knowledge on the cellular signaling network underlying normal brain function and will also provide insights into pathological processes associated with synapse dysfunction and axonal damage.