Johns Hopkins University

NIH Research Projects · FY 2024 · 2023-07

Project Summary Chronic obstructive pulmonary disease (COPD) affects approximately 10% of adults above the age of 40 and is the third leading cause of mortality worldwide. Comorbid diseases commonly accompany COPD and are important determinants of COPD outcomes. In addition, exercise capacity and physical activity are strong independent predictors of all-cause mortality in COPD patients. The two important determinants of exercise capacity are hemoglobin level, the limiting factor for oxygen carrying capacity, and iron level, which dictates tissue oxidative capacity. Thus, while iron deficiency and anemia are related, they are distinct conditions with differing mechanisms of pathophysiology. Currently, compared to anemia, less is known regarding the association between iron deficiency and COPD morbidity. In limited observational and retrospective clinical studies, iron deficiency has been shown to be associated with self-reported exacerbations, worse exercise tolerance, and increased severity of chronic lung disease-associated pulmonary hypertension. Regarding treatment, there have been proof-of-concept studies showing improvement in exercise capacity with IV iron repletion in small cohorts of COPD patients. However, given the small scale of the studies thus far, it remains unknown whether all COPD patients are affected similarly by iron deficiency and whether iron repletion will provide equal benefit. The main object of this proposal is to understand the association between iron profile and COPD morbidity through two novel aims. First, to determine the association between iron profile, specifically ferritin and transferrin saturation, and COPD-related hospitalization by conducting a retrospective secondary analysis of a large COPD patient data registry with approximately 85,000 individuals. Second, to prospectively determine the association between iron profile and 2a) hospital readmission rate and 2b) functional status by physical activity level, in a cohort of patients recently hospitalized for COPD exacerbations. The second aim will be nested in an observational cohort study of patients recently hospitalized for COPD exacerbations that is enriched for exacerbation events. We will obtain iron profiles at 1-week post-index hospitalization and the cohort will be followed for 12 months with regular interval in-person or telephone assessments for exacerbations and validated respiratory symptom measures. Physical activity level will be acquired through step count and heart rate monitoring. This proposal provides an excellent training vehicle for patient-oriented clinical research through hands on experience following a cohort from enrollment to final analysis. I will also develop expertise in basic large data management and physical activity data acquisition and analysis. If we find that iron deficiency is associated with COPD morbidity, future investigation of treatment with iron repletion and assessment of benefit versus harm would be warranted, and would serve as the foundation for my future K-level career development award.

NIH Research Projects · FY 2026 · 2023-06

ABSTRACT Dysregulated Th2 responses are central to the pathogenesis of allergic diseases. The central dogma is that classical dendritic cells (cDCs) are the primary drivers of Th2 cells, this has been largely established using strategies targeting CD11c, which while expressed by cDCs, is also present by other cells like monocytes and macrophages. Our data demonstrates the existence of population of MafB+CD11c+MHCIIhi interstitial macrophages (MHCIIhi IMs), significantly induced in response to house dust mite (HDM). Thus, previous strategies aimed at cDCs may have co-targeted these IMs. Using specific targeting, we show for the first time that these MHCIIhi IMs are central to driving allergen-induced Th2 responses in the airways. Our data propose that the development of Th2 immunity, which has long been the purview of dendritic cells, now includes a central role for MHCIIhi IMs. Consistently, we also find that HLA-DRhi macrophages are elevated in the tissue of patients with allergic nasal polyps. Although their regulation during allergy is not understood. Using chemogenetic approaches, we find that pulmonary innervation emanating from the vagal ganglia (VG) directly induces MHCIIhi IM accumulation during HDM-induced allergic airway inflammation, strongly indicating that VG neurons contribute to IM accumulation in response to allergen. Therefore, vagal ganglion-neuropeptide-IM crosstalk acts as a potential axis mediating airway allergy. Exploring the bioenergetics of these cells, we find that MHCIIhi IMs appear to rely heavily on glucose metabolism for function. They express the highest levels of glycolysis- associated genes, and impairing glucose metabolism decreases their ability to take up HDM, something not seen in cDCs in vivo, suggesting that IMs are intrinsically different than cDCs in their reliance on glycolysis for antigen- presenting function. Further, blocking glycolysis reduces eosinophils, Th2 cells, and IgE, but not neutrophils, cDCs, or IL-13+ILCs. Lastly, we found that HDM-elicited MHCIIhi IMs are also highly enriched for arginase-1, a canonical marker of M2 macs, more so than any other myeloid cell type, including AMs. We postulate that innate cytokines act as microenvironmental signals that condition IMs, favoring the development of Th2 cells. Seeking to understand this mechanism, we found that IMs express high levels of the IL-33 receptor, ST2 and eliminating IL-33 signaling impacts arg1+IMs, but not total IMs. Moreover, we found that neuronal inputs induce ST2 expression, thus sensitizing macs to IL-33. In sum, we hypothesize that HDM-elicited IL-33 promotes an M2-like polarization state, favoring an MHCIIhi IM-T cell dialog that drive Th2 responses. To examine this, we propose to: 1) Examine the neuronal pathways regulating MHCIIhi IM accumulation, 2) Examine the glycolytic program of MHCIIhi IMs, and test its requirement for Th2 responses, 3) test neuropeptide-IL-33 axis that drives alternative MHCIIhi IMs polarization favoring Th2 development.

NIH Research Projects · FY 2025 · 2023-06

Abstract PROJECT SUMMARY Mika Matsuzaki, PhD, MPH, MS, is an Assistant Professor of Human Nutrition in the Department of International Health at the Johns Hopkins Bloomberg School of Public Health (BSPH). She seeks a K01 Award to gain skillset, knowledge, and mentored research experiences through exposure to diverse aspects of food systems and systems science research. This award is a critical step for her to complete the career transition into an independent scholar contributing new insights on systemic interventions to prevent and reduce youth obesity across all populations. The proposed training and study build upon her strong training in nutritional epidemiology, school nutrition policies, and food environments using advanced statistical techniques. The training will build her expertise in the use of mixed-methods, systems science approaches including simulation models examining school-centric food systems and youth obesity. Obesity is increasingly recognized as a systems problem, requiring multi-level, multi-component solutions. Previous research, including my own, has shown that at the population level, youth obesity disproportionately affects various sociodemographic groups. Given the persisting disparities in youth obesity, novel solutions need to be developed. To this end, the proposed study will seek ideas for such solutions through examination of factors within food systems that may have contributed to unexpectedly low obesity prevalence seen in a handful of schools (Aim 1), which we call positive deviators. We will then estimate the potential impact of introducing new changes in food systems to improve diet for students in other school settings in simulation models (Aim 2). Dr. Matsuzaki has access to an excellent research environment and renowned scholars at Johns Hopkins University (JHU) as well as at her collaboration institutions, San Francisco State University (SFSU) and the City University of New York (CUNY). She has built a strong mentoring team covering all training and research components with Dr. Joel Gittelsohn, PhD, MPH (BSPH, primary mentor); co-mentors Dr. Emma Sanchez-Vaznaugh, ScD, MPH (SFSU), Dr. Jess Fanzo, PhD (JHU), Dr. Bruce Y. Lee, MD, MBA (CUNY), and Dr. Takeru Igusa, PhD (JHU). Dr. Matsuzaki will gain hands-on experiences through her proposed research in systems science and youth obesity while obtaining necessary content expertise and experiences through regular meetings and study activities with her mentors, courses, workshops, seminars, scientific meetings. The K01 mentored research training and experience will enable Dr. Matsuzaki to achieve independent scholarship with expertise in systems science approaches to youth obesity disparities and an ability to design and conduct large-scale simulation studies and develop and test new systemic interventions in subsequent R01 studies.

NIH Research Projects · FY 2025 · 2023-06

PROJECT SUMMARY/ ABSTRACT There has been little advancement in overall survival for patients with malignant peripheral nerve sheath tumor (MPNST), despite decades of research and many clinical trials, and thus novel therapies are needed. While loss of NF1 GTPase-activating protein function suggests that targeting RAS may be a logical therapeutic approach, there is currently no approved drug that effectively and directly targets wild-type RAS. The design of novel therapeutic combinations requires a deep understanding of the signaling pathways regulated by hyperactive RAS and feedback that conditions the response to their inhibition. MEK, SHP2, and CDK4/6 are critical nodes in RAS effector signaling in MPNST tumors, and combinations of small molecule inhibitors that target them may have synergistic anti-tumor activity. Further, adaptive signaling changes in response to RAS effector pathway inhibition occurs not only in tumor cells but also in cells that comprise the tumor immune micro- environment (TIME). Thus, the characterization of the TIME in our murine model of MPNST, and its modulation via small-molecule inhibitors of the RAS pathway, will identify key immune pathways leading to the reprogramming of intratumoral myeloid cells, enhancing endogenous immune responses. We propose three Aims: 1. Identify and functionally validate mechanisms of acquired resistance to SHP2 inhibitors in MPNST in order to develop novel therapeutic combinations. We will determine how tumors become resistant to SHP2i, as well as to SHP2i +CDK4/6i in combination, and will perform genetic manipulation studies in order to functionally validate priority hits. 2. Determine the efficacy and tolerability of combination small- molecule inhibitors of RAS signaling, particularly SHP2i + CDK4/6i, in in vitro, patient-derived xenografts (PDX), and immune-competent syngeneic Nf1 -/-/Ink4a/Arf -/- mouse models. We will test the effects of SHP2i and CDK4/6i single agents or combinations as tools to probe the biochemical and biological changes that occur upon pathway perturbation, and will determine the mechanism and anti-tumor activity of these combinations, with a priority focus on the SHP2i+CDK4/6i combination, based on our advanced preliminary data. 3. Reprogram the intratumoral pathological myeloid cells via treatment with the combination of SHP2i and CDK4/6i in murine MPNST. Our preliminary data suggest that the landscape of MPNST is densely populated by tumor infiltrating myeloid cells. To evaluate the effects of these agents and their combinations on the TIME, we will utilize single cell transcriptional analysis, multiparameter flow cytometry and multiplex immunohistochemistry to decipher the specific effects of these drugs on cell types that comprise the tumor, including both immune-infiltrating and primary tumor cells. By determining the efficacy and mechanism of these rationally-designed therapeutic strategies in both PDX and immune-competent mouse models, our studies will provide mechanism-based, promising combinatorial approaches that may be rapidly and successfully translated to the clinic, and will inform effective patient selection strategies and the development of novel clinical trials for patients with MPNST.

NIH Research Projects · FY 2026 · 2023-06

ABSTRACT Colorectal cancer (CRC) is diagnosed at advanced stages in many low- and middle-income countries (LMICs). The lack of knowledge of CRC signs and symptoms by patients and community health practitioners frequently leads to delayed presentation with Stage 3-4 disease. This initial delay, paired with limited colonoscopy facilities, leads to prolonged diagnostic delays. The result is a 5-year mortality rate in LMIC up to 5 times higher than that in USA. An innovative solution to this problem could be an affordable, easily deployable, “point of care” molecular test to identify and prioritize patients likely to have a malignancy for expedited colonoscopy and pathology review leading to better outcomes. Continuing our established collaboration with our industrial partner, Cepheid, we propose to build on our strong published data on hypermethylated markers in CRC to develop an affordable, <3- hour, automated CRC-methylation detection blood test that analyzes a panel of five hypermethylated genes in cell free DNA from 1 ml of plasma. The proposed innovations could lead to a single-cartridge assay for quick CRC detection with a 3-fold reduction in cost. In Aim 1a, we will optimize a cartridge-less bisulfite DNA conversion method for plasma and test its efficiency in Patient Set 1 plasma (N= 20 malignant, 20 normal). In Aim 1b we will select one optimal 5-marker panel out of 20 CRC markers using DNA from FFPE samples from the U.S and Nigeria (N= 30 malignant, 30 benign), and one optimal “pan” set will be confirmed in plasma using U.S Patient Set 2 and Nigeria Set 3 (N=35 malignant, 35 benign). In Aim 1c, we will evaluate analytical performance of the CRC-MD assay. Intra-assay reproducibility will be assessed on multiple aliquots of U.S Patient Set 4 plasma (N=35 malignant, 35 benign). Inter-operator reproducibility will be determined using replicate aliquots of plasma from Patient Set 4 (N= 35 malignant, 35 benign). The goal of Aim 2a is to technically validate the CRC-MD assay using prospectively collected samples in Nigeria. We will first select a threshold in a Training set of plasma from Patient Set 4 (N=90 malignant, 90 benign) to optimally balance sensitivity and specificity, and validate performance of the selected threshold in a Test set of plasma from Patient Set 5 (N= 90 malignant, 90 benign). Accuracy (sensitivity, specificity, and positive- and negative-predictive value) of CRC- MD-based diagnosis to distinguish benign versus malignant disease will be measured using histopathological diagnosis of the lesion as the gold standard. Lastly, in Aim 2b, to determine whether the performance of the CRC-MD assay is altered by select patient characteristics, we will test its clinical accuracy among specific patient subgroups classified by age, sex, BMI, and tumor characteristics. Our prior success in developing automated cell-based/liquid biopsy assays with Cepheid has established the path ensuring an accurate and reliable test. This intervention could be cost saving by hastening colonoscopy for those who need it urgently, thus expediting detection and treatment of CRC in LMICs. This will save thousands of lives yearly. This study will also facilitate further development of the CRC-MD assay moving toward future commercialization and access globally.

NIH Research Projects · FY 2025 · 2023-06

Project Summary DESCRIPTION (provided by applicant): The goal of this project is to provide new information about the specific brain circuits which enable us to regulate our posture, movements, and arousal levels when we are exposed to unexpected stimuli or potentially threatening conditions. Several psychiatric and neurological disorders are associated with impairments in motor tone and arousal regulation which manifest as sensory hypersensitivity, excessive startle reactivity, and increased anxiety. This research focuses on the cerebellum, a part of the brain known best for its role in coordinating movements and learning to anticipate when and how to move, but is also important for regulating wake-state arousal levels. Researchers and clinicians currently lack specific information needed to develop and target new therapeutic treatments to patients who suffer from dysregulation of defensive arousal. The specific objectives of this project are to provide anatomical, physiological, and functional information about specific cerebellar cell types which regulate movements of the trunk, head and eyes and levels of arousal via their synaptic connections with brainstem control centers. To achieve these objectives, anatomical circuit analyses will map differential synaptic connectivity of specific cerebellar neurons, neurophysiological analyses will be used to monitor activity in specific types of cerebellar neurons under conditions of spontaneous and sensory- evoked arousal, and behavioral and physiological analyses will determine the impact of manipulating activity of specific cerebellar cell types on the online and learned regulation of arousal responses to unexpected or potentially threatening stimuli. These experiments will provide a critical foundation for developing pharmacological or neurostimulation therapies for treating patients who suffer from impairments in the abiilty to regulate how they respond to unexpected threatening stimuli.

NIH Research Projects · FY 2025 · 2023-06

Summary Human neurochemistry undergoes dramatic changes in early childhood, due to the rapid pace of development. However, techniques for assessing neurochemistry non-invasively by magnetic resonance spectroscopy (MRS) in young children are limited. Spectral editing is the gold-standard for detecting MRS signals from key neurometabolites such as the neurotransmitters glutamate (Glu) and GABA, the neuromodulators N-acetyl aspartyl glutamate (NAAG) and aspartate (Asp), the redox compounds glutathione (GSH) and ascorbate (Asc), the anaerobic glycolysis product lactate (Lac), and the membrane lipid precursor phosphorylethanolamine (PE). Measurement of these lower-concentration metabolites is vital for investigating healthy and disrupted neurodevelopment, including inhibitory dysfunction, oxidative stress, myelination and mitochondrial metabolic disruption. To date, spectral editing has not been applied at large in pediatrics – arguably the arena in which they will be leveraged most powerfully for scientific discovery and clinical value. This project will develop acquisition and analysis tools for multi-metabolite MRS in the pediatric brain, focusing on developing motion-robust acquisitions. It will also acquire reference data for the best-practice analysis of pediatric spectra, including the macromolecular background spectrum and metabolite relaxometry. This project will have a key push-pull interaction with the HEALthy Brain & Child Development (HBCD) Study, a 25-site national study of neurodevelopmental risk factors (including four sites in this proposal). HBCD applies the acquisition and analysis methods developed by PI Edden's group (HERCULES and Osprey), and Drs. Edden and Wisnowski are co-chairs of the HBCD MRS working group. Dissemination of methods from this project will directly support HBCD, and this new focus on methods development for pediatric cohorts will allow us to directly address technical issues as they arise in HBCD. Data acquired during HBCD will supplement the data acquired in this grant as we develop a profound new understanding of the neurometabolic trajectory of early childhood.

NIH Research Projects · FY 2024 · 2023-06

The goal of this project is to develop a Wireless, fully Implantable, bidirectional Cortical Neuroprosthetic System (W-ICONS) for restoring sensorimotor function through an interface with intact upper limb areas of primary motor and sensory cortex. Technologies that enable direct communication to and from the brain have increasingly shown promise for restoring independence to people affected by high spinal cord injuries. Despite these advances, neural interface systems are still mostly confined to laboratory settings, requiring a team of researchers to handle cumbersome transcutaneous interfaces, extensive wiring, and bulky devices for recording and stimulating neural activity. Further, these devices have typically been equipped exclusively with neural recording capabilities. The W-ICONS device would be the first wireless, bidirectional—incorporating neural recording and stimulation—cortical implant for tetraplegic individuals, creating a truly portable device for use outside the lab environment. This proposed translational study benefits from over a decade of clinical studies with microelectrode arrays, demonstrating safety and efficacy in restoring lost sensorimotor functions. The Brain Gate and Revolutionizing Prosthetics clinical trials have demonstrated that functionally relevant control over prosthetic arms and communication devices can be achieved and maintained for years. More recent studies from a number of groups (including our own) have shown that intracortical microstimulation (ICMS) can provide stable, localized sensory percepts capable of improving task performance on reach-and-grasp tasks. Critically, our team has led and received FDA and institutional regulatory approvals for four first-in-human demonstrations. Here, we will be extending our team’s state-of-the-art fully implantable wireless recording system with the addition of stimulation capabilities. Benchtop verification of the W-ICONS system (Aim 1), will be followed by preclinical testing of the device in an animal model, will support an FDA IDE submission (Aim 2) to conduct an early feasibility study (Aim 3) at JHU of the W-ICONS with individuals affected by high spinal cord injury (tetraplegia). The aim of the clinical study at JHU is to validate chronic safety and efficacy of the W-ICON system in two participants in a 1-year study (minimum). Safety will be demonstrated if the device is not explanted due to safety reasons during the study period. Demonstration of efficacy will require control of sensorized robotic arms in pick- and-place tasks (e.g., Action Research Arm Test) and reported perception of ICMS in the hand area. Successful demonstrations will support a study protocol amendment to go beyond one year of implantation and to transition use of the device to patients’ homes.

NIH Research Projects · FY 2025 · 2023-06

PROJECT SUMMARY In the animal kingdom, sexual dimorphism, or phenotypic differences between the sexes, is seen in most species. In Drosophila, the key factor controlling sexual dimorphism is Doublesex (Dsx), the founding member of the conserved Doublesex/Mab-3 Related Transcription Factor (DMRT) family. DMRTs have central roles in sex determination across many species including flies, humans, and mice. Although few Dsx targets have been characterized, our lab has shown that Dsx regulates sex-specific steroid hormone Ecdysone (E) signaling through female-specific Ecdysone Receptor (EcR) expression, and that this functions to promote ovary development and repress testis development at a key developmental timepoint. Bioinformatic analyses has been used to predict Dsx targets, and many of these are transcription factors that contain a Broad-complex, tramtrack, and bric-a-brac (BTB) domain, a protein-protein interaction motif. To identify Dsx targets that play a role in sexual dimorphism of the gonad, I performed a reverse screen of BTB domain proteins containing putative Dsx binding motifs using RNA interference. As a result, I found that loss of mamo in somatic cells of the gonad led to severely disorganized ovaries and, in some cases, the formation of rudimentary testes in XX animals. Given these findings, I hypothesize that mamo is critical for proper development in the Drosophila ovary, and that it functions downstream of Dsx and E signaling to help establish a female sexual fate. This hypothesis will be addressed by first examining the cell-type-specific expression of Mamo throughout development and performing genetic interaction assays with dsx. I will characterize what cell types are affected in the absence of mamo using cell-specific markers and ascertain whether loss of mamo results in sex transformation properties of the ovary. A second BTB domain protein, Chinmo, has been shown to be important in the testis, and the relationship between mamo and chinmo, and how E signaling regulates these factors, will be determined. This work will expand current knowledge on how DMRTs control sexual dimorphism and could uncover genes critical for sexual identity in both flies and mammals. Due to the universal nature of DMRTs in controlling sex-specific development, understanding their targets and how they function is of great importance for reproductive health and has the potential to broaden our knowledge of human infertility.

NIH Research Projects · FY 2026 · 2023-06

Due to changes in cannabis policy, most Americans now have access to an array of retail cannabis products. An estimated 5.5 million Americans are registered with state-regulated medical cannabis programs and the therapeutic use of federally legal hemp (e.g. CBD) products is widespread. Despite most states having legalized medicinal cannabis use, little is known about the characteristics of these patients, the cannabis products they use, or the patient-level health impact of their medicinal cannabis use. Filling these gaps in knowledge remains an urgent public health need. We propose to: 1) design and implement a prospective medicinal cannabis patient registry for longitudinal data collection. We will recruit a nationally representative cohort of patients newly initiating the use of cannabis for therapeutic purposes into a longitudinal observational research registry. We will assess patient demographics, cannabis product use, and a range of health outcomes prior to and repeatedly after initiation of medicinal cannabis use via web-based surveys. A subset of patients will complete intensive data collection via ecological momentary assessment (EMA) and/or provide biospecimens for clinical chemistry testing to determine the impact of medicinal cannabis use on daily functioning and symptom management in addition to potential unseen harms such as liver toxicity; 2) Establish a program of medicinal cannabis product testing based on adverse event reporting and other mentions of injury/harm in the patient registry or via surveillance of other data sources (e.g. poison control data, FDA warnings, online forum posts). Products associated with adverse events or other harms will be targeted for testing related to dose-label accuracy, cannabinoid content, and presence of contaminants; 3) Identify and integrate existing sources of data that can inform the health impacts of medicinal cannabis use. This includes electronic medical record (EMR) databases as well as prior and ongoing research projects of the study team (e.g., Realm of Caring Observational Research Registry); 4) Develop and implement a website that will include annual summary reports of the combined data, an application process for researcher access to de-identified data for the conduct of novel analyses, and an archive of published papers related to the health impacts of medicinal cannabis use. A pilot research program to fund scientists interested in probing the data repository will be established. Our team includes internationally recognized expertise in the comprehensive research methods proposed. The result of this project will be a rich data resource for understanding the health impacts of medicinal cannabis use. Data will include patient-level outcomes across a broad range of therapeutic purposes and include use of a variety of cannabis products. Data will help inform clinical decision making related to initiation of cannabis products, guidance on product, route of administration and dose selection, risks related to adverse events, injury/poisoning risk and abuse liability. Findings will also help local and federal government agencies develop effective policies, programs, and regulatory strategies to mitigate harms associated with the rapidly growing cannabis industry.

NIH Research Projects · FY 2026 · 2023-06

PROJECT SUMMARY Meeting targets set to end AIDS as a major public health threat by 2030 requires reaching all populations, particularly those with the highest burden, such as people who inject drugs (PWID). PWID continue to experience some of the fast-growing HIV epidemics globally. Injection drug use is increasingly accounting for new HIV infections in both low- and middle-income countries and countries that once saw notable declines in HIV incidence among PWID. Even in countries with notable declines in HIV incidence among PWID, such as the United States, the rise of prescription opioid use has resulted in increased heroin injection, increased overdose rates, and outbreaks of HIV. Despite decades of investigation into the behavioral drivers of HIV incidence, accurately predicting who is at the highest risk of becoming infected with HIV remains challenging. Yet, this information is critical for preventing outbreaks and tailoring interventions. These tools are even more critical at the final stages of disease control, elimination, or eradication programs which require disproportionately more effort and resources than in preceding stages to identify those at risk, especially in a setting of dwindling resources and emerging pandemics. As we rapidly approach the ambitious 2030 targets, the same will be true of HIV, even more so among hard-to-reach populations such as PWID, and we need early warning systems to guide a more targeted public health response We previously demonstrated that PWID accumulate blood-borne nonpathogenic viruses in the plasma before hepatitis C virus infection. We also have early data showing that sequences of these nonpathogenic viruses reveal epidemiologic links. This study builds on these findings to explore whether the plasma virome in PWID can be further used as a bioindicator of HIV risk and whether it can be leveraged to interrupt HIV outbreaks before they occur. To test this, we utilize a rare set of longitudinal social (injection partner) and spatial (injection venue) network data along with detailed individual-level risk factors and HIV sequences from a high-incidence cohort of over 2,500 PWID in New Delhi, India. To date, this cohort has observed over 159 HIV seroconversions. We plan to characterize the plasma virome using baseline specimens from participants who later acquired HIV to determine if virome richness independently predicts HIV incidence and to assess the added value of a bioindicator over established risk prediction tools. Additionally, we plan to sequence participants comprising complete contact networks and leverage next-generation sequencing approaches that capture the diversity of nonpathogenic viruses circulating within and between hosts to employ phylogenetic methods aimed at determining whether plasma virome sequences can accurately infer transmission networks. By using routinely collected samples, this work could lead to more robust molecular surveillance methods that can guide public health officials in targeting interventions to prevent HIV outbreaks and focus limited resources for the greatest impact.

NIH Research Projects · FY 2026 · 2023-06

Project Summary The lipid composition of cell membranes controls bilayer permeability and fluidity as well as the folding and activity of integral membrane proteins, which comprise ~30% of the human proteome. Consequently, the lipid composition of membranes is subject to tight homeostatic control. Over the past 60 years, we have learned a tremendous amount about membrane lipid cell biology, largely from model organisms because forward genetics in cultured human cells remained challenging. CRISPR technology now permits a direct examination of these cellular functions in human cells, opening up a new era of mammalian cell genetics. Our MIRA research strategy is to apply mammalian cell genetics to long-standing questions in cell biology, specifically focusing on the regulation of membrane lipid homeostasis. Over the next 5 years, we will use genetics to address two challenges. For Challenge #1, we will identify new regulators of plasma membrane lipid composition. For Challenge #2, we will discover the mechanism of lysosomal fatty acid export by characterizing genes required for the assimilation of low-density lipoprotein (LDL)-derived fatty acids. Overall, these proposed MIRA studies will make fundamental contributions to the fields of membrane biology, intracellular lipid transport, LDL receptor function/endocytosis, the SREBP pathway, and regulation of lipid synthesis. Given that modulation of cholesterol synthesis and LDL receptor function are primary interventions in the treatment of hypercholesterolemia, these studies may identify new therapeutic targets for the prevention of heart disease, a leading killer of adults in the United States.

NIH Research Projects · FY 2026 · 2023-06

Project Summary Fatal overdose is a major cause of mortality among people who use opioids (PWUO). Yet, fatal overdose can be prevented when naloxone is promptly administered. Bystanders of an overdose are well positioned to administer naloxone and can include both people who use and do not use drugs. In our prior work, we have shown that PWUO can be peer educators (PEs) for overdose prevention. In previous interventions, we have focused on training network members who use drugs to respond to an overdose. Yet, pilot data suggest that overdoses are also often witnessed by people who do not use drugs. Social norms may impact PWUO engaging in conversations about overdose prevention with non-using networks as well as non-using network members’ willingness to always carry naloxone. Based on pilot data, we propose expanding an overdose peer education intervention to focus on non-using network members and to address social norms. The intervention seeks to prepare network members to respond to an overdose and normalize discussion about overdose prevention planning between PWUO and their network members. Using an RCT study design, 300 index PWUO will be recruited along with 450 network members. The indexes will be randomly assigned to the (1) standard of care (SOC) or (2) an experimental peer education condition (PEC). The proposed design allows examination of the effectiveness of the intervention to train non-using network members and enhance communications among PWUO and their network members. We will use mHealth to assess geographic coverage of peer education and geospatially situated norms in order to understand factors associated with the geospatial coverage of the PEs. The RE-AIM framework will guide the collection of qualitative interview data to identify barriers and facilitators to intervention implementation. Participants will be assessed every 6 months for 2 years. The proposed design will also allow for the longitudinal examination of pathways between social and psychological, and mental health factors and overdose behaviors, which can guide future interventions. Aim 1: Implement and evaluate an equal attention 2-group RCT PWUO peer educator intervention that focuses on training network members, especially non-drug using network members, to encourage overdose prevention and response behaviors. Aim 2: Assess factors associated with geospatial coverage of peer outreach and geospatially/socially situated social norms using EMA/mHealth.

NIH Research Projects · FY 2026 · 2023-05

Project Summary The objective of our work is to decipher how stromal cells interact with immune cells to alter tissue biology to support resistance to an intestinal infection. Our work will use mice infected with the intestinal helminth parasite Heligmosomoides polygyrus bakeri (Hp), which is a recognized inducer of type 2 immunity. In this system, mice are resistant to reinfection following curative treatment of primary infection, and resistance is Th2 cell-dependent. We recently reported that during Hp infection mesenteric adipose tissue (mAT) becomes populated by long-lived Th2RM cells which make Amphiregulin and TGFβ1 in addition to the signature Th2 cytokines IL-4, IL-5 and IL-13, and that deletion of the Amphiregulin receptor on stromal cells is associated with increased susceptibility to Hp. Further, stromal cells within mAT, and especially a subset of stromal cells with multipotent potential (multipotent progenitor cells, MPC) to differentiate into fibroblasts or adipocytes, become activated and makes the alarmins IL-33 and TSLP that are able to promote Th2 RM cell activation. We have localized both Th2RM cells and MPC to interstitial spaces in mAT. We propose that mAT interacts with the intestine to participate in the protective response against Hp. This involves the production of alarmins to support Th2RM cell activity, and to produce extracellular matrix (ECM), which we postulate is important for trapping invading parasites in granulomas, and supporting soft tissue integrity and repair during infection. Based on our published findings and new preliminary data, we hypothesize that Th2RM cells and stromal cells work as a team to mutually facilitate each other’s activation and exert host protective effects during Hp infection. On the basis of our recently published findings and new preliminary data on innate training in MPC, and lipid metabolism and motility of Th2RM cells, we have developed two Specific Aims: 1, To understand the role of MPC in shaping host resistance to Hp; and 2, To determine the function, antigen specificity, and cell- intrinsic metabolic and migratory features of mAT-resident Th2 cells. To address these Aims we will use RNA seq, ATACseq, flow cytometry, parasitological techniques, advanced imaging of cell movement ex-vivo, measurements of tissue stiffness, ex-vivo studies of the functional properties of Th2RM cells and stromal cells, and in vivo loss of function models to probe the roles of Amphiregulin, TGFβ, IL-33 and TSLP. Our work has the potential to reveal novel features of stromal cell biology that are integral to underlying effector mechanisms of resistance and immunity to intestinal pathogens, and to highlight potential points of intervention for manipulating stromal cell biology as it relates to type 2 immunity in health and disease. Our findings may have relevance to understanding human conditions such as atopy/allergy, impaired wound healing, fibrosis and cancer, in which dysregulated stromal cell biology and ECM production are implicated.

NIH Research Projects · FY 2026 · 2023-05

Under the HIV Organ Policy Equity (HOPE) Act, early studies show that kidney transplantation (KT) from donors with HIV to recipients with HIV (HIV D+/R+) expands the donor pool, reduces wait-times, and yields excellent short-term patient and graft survival. However, significant rates of rejection were observed with a trend towards higher rates in D+ recipients compared to HIV-uninfected donor (D-) recipients. Understanding the impact of D+ on rejection, underlying mechanisms, and the impact on long-term outcomes is critical. There are potential virologic and immunologic explanations for higher rejection in HIV D+/R+ vs D-/R+ KT. D+ kidneys harbor HIV and are more likely to harbor other co-infections such as CMV. These pathogens may trigger an inflammatory response, enhancing T-cell or antibody(Ab)-mediated pathways of rejection. Understanding the type of rejection and risk factors will inform interventions to improve outcomes, e.g. HIV D+ selection criteria, immunosuppression, or targeted monitoring and prophylaxis for co-infections. We propose Expanding HOPE, a multicenter trial comparing outcomes in 100 HIV D+/R+ KT and 100 D-/R+ KT at 15 transplant centers. We will combine this cohort with prior cohorts of HIV D+ and D- KT from our HOPE in Action Consortium, established in 2015. HOPE in Action has accrued approximately 325 HIV+ KT recipients to date; this larger cohort provides sufficient statistical power to determine the impact of HIV D+ organ on rejection and it will also allow us to determine long-term patient and graft outcomes beyond 5 years. Within this trial, we will perform comprehensive mechanistic studies to examine both T-cell and Ab-mediated rejection pathways. We will quantify changes in donor-specific and viral-specific (HIV CMV) T cells using an activated induced marker (AIM) assay in D+ and D- recipients, with and without rejection, over time. We will perform TCRβ immunosequencing on sorted AIM+ cells vs unsorted T cells to track T cell receptor dynamics. With VDJ-specific PCR, we will quantify expanded clones, including donor or viral AIM+ cells, post-KT. We will also characterize inflammation and the humoral response to infections and human proteins (donor, self). We will use a multiplexed electrochemiluminescence detection assay to quantify >30 cytokine and chemokines to characterize inflammation, and phage display and immunoprecipitation sequencing to characterize Abs to >1300 viruses, >14,000 microbial toxins/virulence factors, and >27,000 human autoAbs. Our HOPE in Action Multicenter Consortium has an established track record, successfully completing multicenter transplantation trials, including HIV D+/R+ KT. We will leverage our existing infrastructure to oversee operations, data management, analysis, and safety monitoring. In summary, the proposed research will determine the impact of HIV+ donor kidneys on rejection, will quantify long term outcomes, and elucidate risks and mechanisms of rejection. This knowledge can improve and expand HIV D+/R+ KT, and can provide important insights about alloimmunity more broadly.

NIH Research Projects · FY 2026 · 2023-05

PROJECT SUMMARY Cancer vaccines have significantly advanced cancer immunotherapy; and recent successes of mRNA vaccines have raised prospect of generating potent anti-tumor response by specifically delivering mRNAs encoding tumor-associated antigens to antigen presenting cells (APCs). However, APC activation elicited by nanoparticles containing antigen mRNAs is rather limited. Circulating monocytes offer a promising cell target as an abundant APC precursor that can be deposited to spleen, lymph nodes, and tumor tissue following polarization and activation. The overall objective of this study is to engineer kinetically assembled poly(beta- amino ester) (PBAE) /mRNA nanoparticles (KaNPs) that can specifically deliver mRNAs encoding tumor antigens and immunoadjuvants into circulating monocytes in vivo and demonstrate the safety and efficacy of this new mRNA cancer vaccine platform. This study is built on the preliminary results showing biodegradable PBAE/mRNA KaNPs with an optimized size of 400 nm mediated preferential transfection of circulating monocytes following intravenous (i.v.) injection, leading to more effective transfection and deposition of circulating monocytes and a higher level of tumor-killing activity compared to the standard small size PBAE/mRNA nanoparticles. In this proposed study, we plan to pursue four specific aims: (1) optimize the composition, size, and surface functionality of PBAE/mRNA KaNPs to improve targeted mRNA delivery efficiency into circulating monocytes in vivo, (2) characterize pharmacokinetic profile of PBAE/mRNA KaNPs and define functions of transfected circulating monocytes in vivo, (3) assess the immunotherapeutic efficacy of PBAE/mRNA KaNPs in suppressing tumor growth in combination with TLR9 and STING agonists in mouse tumor models, and (4) develop an GMP-compliant, shelf-stable, lyophilized PBAE/mRNA KaNP formulation and validate the efficacy in a mouse model. If successful, this study will uncover structure-function relationships in a previously inaccessible size range (200–1000 nm) for gene therapy carriers, demonstrate circulating monocytes as a potent mRNA therapeutic target and the role of KaNP-transfected circulating monocytes in potentiating antitumor immune responses, and inspire rational design of new mRNA-based immunotherapies for treatment of solid tumors and metastatic cancers.

NIH Research Projects · FY 2025 · 2023-05

Abstract In the last 5–10-years new model systems, to study ALS, FTD and other dementias, based on patient derived induced pluripotent cell lines have provide great insight into highly relevant disease-causing pathways as well as fundamental neuronal and glial cell biology. New studies using these, and other model systems suggest the nuclear transport is the fundamental injury linked to both familial sporadic ALS and FTD. Emerging studies now implicate nuclear transport and the nuclear pore complex in multiple different neurodegenerative diseases including ALS, FTD, Huntington’s disease and even aging. These studies are beginning to identify candidate therapies for sporadic forms of the disease. The nuclear pore complex is diverse, and mutations of its constituent proteins can lead to a wide range of different degenerative diseases. Thus, studies of the CNS nuclear pore and nucleocytoplasmic transport have pathogenic implications that are wide ranging. This proposal will comprehensively investigate the biology of CNS nuclear pores and nuclear transport- the fundamental properties in different neuronal and glia, mechanisms by which the nuclear pore is disrupted, include possibly disease initiating biology involving the ESCT3/CHMP7 pathways, how the nuclear pore complex is disrupted in sporadic and familial forms of the diseases utilizing several complementary models including C9-ALS fly and mouse models and iPS neurons and brain tissue from sporadic and C9orf72 mutant ALS/FTD patients. We will also investigate whether modulation of nucleocytoplasmic transport and /or repair of the nuclear pore complex may be a therapeutic strategy for ALS/FTD. Our emerging data teach that there are multiple candidate therapeutic opportunities for this pathway and neurodegeneration. As we have now learned that defect on the nuclear pore complex are upstream of the disruption of TDP43 nuclear location and loss of function, this pathway may have relevance to not only ALS and FTD – but other neurological injuries involving TDP43 misregulation. Finally, studies over the last decade have revealed that neurodegenerative diseases are not simply a disorder of neurons, but that glial cells also contribute to pathophysiology. Many studies have implicated aberrant astroglial function in ALS and neurodegeneration. Regional alterations of astroglia have long been known—but how this occurs and whether astroglia exist as functional/molecular subtypes has been unclear. New studies from our group and others now suggests real subtypes of astroglia exist, may have specific functions n modulating cortical dendritic and synaptic biology and may be selectively altered in ALS. The biology of these newly identified subgroups will be explored in this proposal and how they alter spines/dendrites, neuronal elements known to be dramatically altered in neurodegeneration.

NIH Research Projects · FY 2026 · 2023-05

SUMMARY Epilepsy is a neurological disorder that is marked by sudden recurrent episodes of abnormal electrical activity in the brain, known as seizures. This disease plagues more than 60 million people globally, with the same burden of disease as breast cancer in women and lung cancer in men. First line of treatment for patients with epilepsy are anti-epileptic drugs (AEDs). If AEDs are not effective in suppressing seizures, then patients may consider alternative treatments including surgical resection of the epileptogenic zone in the brain, electrical brain stimulation, or vagus nerve stimulation. With several treatment options available, one may think that epilepsy is under control. However, this is far from true. Accurately diagnosing epilepsy and then finding an effective treatment can take years to a lifetime, during which patients and families suffer from the stigma of epilepsy, side- effects of ineffective AEDs, extensive and costly hospital stays, poor outcomes of irreversible surgical treatment, and/or less than satisfactory stimulation therapies whose efficacies are physiologically unmeasurable. We propose a program to establish novel EEG biomarkers and computational tools that will enable rapid and accurate diagnosis of epilepsy followed by a rapid path to an effective treatment. Such a program entails major advances in conceptual knowledge of how epileptic cortical networks behave and change during stimulation treatment that will be gleaned from dynamic network modeling (DNM) of EEG. There are many challenges with diagnosing and treating epilepsy that unfolds as one considers the clinical workflow beginning with a patient’s first seizure. First an accurate diagnosis of epilepsy can take months to years, where scalp EEG can be leveraged to confirm diagnosis. However, the gold standard is to look for EEG abnormalities that are indicators of epilepsy (e.g., spikes), which are often not captured or misread. Second, it takes months to years to find effective AED treatment as there is no physiological measure of drug efficacy. For these two pain points, we will leverage a new biomarker that our lab discovered from intracranial EEG called the source-sink metric which is designed to capture pathological network properties that are always present only in epilepsy patients. For 30% of the patient population, no AEDs work, and their alternative treatments include surgical treatment of the epileptogenic zone (EZ) and electrical stimulation therapy. However surgical success rates for drug resistant patients averages 50%, and there is currently no measure of efficacy of neurostimulation treatment, leaving half of treated patients nonresponsive. For these drug resistant patients, we will leverage the source-sink index, derived from DNMs and EEG, to help more accurately localize the EZ to improve surgical success rates, and to track efficacy of stimulation treatment from the FDA approved RNS device. The proposed R35 will address major challenges with novel EEG biomarkers stemming from dynamic network models. Is successful, the program will lead to breakthrough technologies enabling getting to accurate diagnosis and optimal treatment for all epilepsy patients more rapidly (from years to weeks), including the underserved drug-resistant cohort.

NIH Research Projects · FY 2026 · 2023-05

SUMMARY Norepinephrine (NE) is a neurotransmitter released by a small number of neurons in the locus coeruleus (LC), with extensive innervation of the neocortex. Prior work in humans and other mammals led to the hypothesis that LC-NE neurons modulate multiple forms of decision making. This proposal aims to test this overall hypothesis by studying LC-NE neurons in mice performing multiple decision-making tasks. The behaviors to be studied include two types of flexible decision making: how to learn from reinforcement over tens of seconds to minutes in a dynamic choice task and how to rapidly change a motor program based on sensory feedback over hundreds of milliseconds to seconds. The goal of the project is to link action potentials from identified LC-NE neurons to both types of behavior, and determine how large populations of neurons in multiple cortical areas are modulated by NE input to achieve flexible behavior. Three aims test three hypothesis that address different mechanistic questions about the functions of norepinephrine in neocortex: 1) LC-NE neurons modulate reinforcement learning during a dynamic choice task; 2) norepinephrine regulates sensory-driven motor program switching; 3) LC-NE modulates orofacial and prefrontal cortex for effective reinforcement learning and motor program switching. Measurements and manipulation (activation and inactivation) of the activity of NE neurons and their targets in neocortex, during well-controlled behavioral tasks in mice, will enable testing these three hypotheses. Understanding the spatial and temporal dynamics of NE release in cortex will be necessary for understanding flexible decision making in general, and disorders of attention, arousal, and mood that rely on its function.

NIH Research Projects · FY 2025 · 2023-05

Project Summary Many individuals with substance use disorders (SUDs) also experience significant psychological distress or meet the criteria for common mood and anxiety disorders with potentially significant implications for SUD outcomes and SUD treatment effects. Examining these implications is important for identifying optimal treatments for patients with comorbid conditions. Past research on the impact of such comorbidities has produced mixed results, mainly due to small sample sizes or reliance on observational studies. In this proposal, a large-scale study of the impact of 1) mood and anxiety disorder as well as 2) psychological distress comorbidity on SUD outcomes and SUD treatment effects is proposed using data from over 5,000 patients from 20 randomized controlled trials (RCTs) of pharmacological and psychosocial treatments of SUDs sponsored by the National Institute on Drug Abuse. Our aims include the use of modern individual participant meta-analytic methods to combine the individual level data and to examine whether and to what extent SUD outcomes and SUD treatment effects vary among patients with and without comorbidity. Outcomes will include retention in treatment to the end of the trial, continued use of drugs ascertained by urine toxicology and self- report, and social outcomes (including occupational outcomes and criminal justice involvement). In Aim 1, data from RCTs will be combined to examine the impact of psychiatric comorbidity (i.e., mood and anxiety disorders as well as psychological distress, jointly and separately) on the SUD outcomes, irrespective of treatment arm, using mixed effect regression models. The RCT samples will be balanced with regards to socio-demographic and clinical factors that may vary across studies using propensity score methods. Aim 2 will use a similar methodology to examine the moderating effect of comorbidity on SUD treatment effects by examining interaction terms of SUD treatment by comorbidity in mixed regression models. In Aim 3, we will examine whether concomitant medication treatment of mood and anxiety disorders will change the impact of these disorders on the SUD outcomes and SUD treatment effects. In Aim 4, we will reweight the RCT samples to resemble target samples of individuals with SUDs receiving treatment in the general population to address exclusion (and possible under-representation) of patients with severe psychiatric conditions from SUD RCTs. The results from reweighted samples will be compared with the results of the original unweighted samples. The project significantly advances research on the impact of these comorbidities on SUD outcomes and SUD treatment effects using individual participant data from an unprecedentedly large group of rigorously conducted trials that have used a core set of standardized assessments and consistent outcome measures.

NIH Research Projects · FY 2026 · 2023-05

Project Summary This proposal outlines a five-year career development program aimed at promoting the principal investigator to research independence as a clinician scientist in basic and translational neuroscience, with specialization in cell type-specific mechanisms that regulate neuronal autophagy and modify proteotoxicity in Parkinson disease (PD). Applicant: The applicant has completed M.D. and Ph.D. degrees, residency training in neurology, and fellowship training in PD and movement disorders. He has previous experience in neuroscience research using cell and mouse models to study autophagy in spinobulbar muscular atrophy. His career development plan is designed to focus his research on PD pathogenesis and advance his knowledge in bioinformatics, CRISPR gene editing and high-throughput screening, and advanced imaging techniques. In so doing, the training plan outlined herein builds upon his prior training to achieve research independence. He will benefit from continual mentor engagement, regular meetings and ongoing collaborations. He will learn additional research techniques through formal coursework, workshops, and national meetings. These training mechanisms will provide the applicant with the scientific and conceptual skillset necessary for an independent career in neurodegenerative research. Research Plan: PD is a progressive neurodegenerative disorder marked by motor and non-motor/multi-systemic symptoms that lead to profound disability. There is no effective disease-modifying therapy currently available. Neurodegeneration in PD relates to toxic aggregation of ⍺-synuclein, and mounting evidence shows that ⍺- synuclein can be degraded through the conserved pathway of autophagy. However, current methods to modulate autophagy fail to confer neuroprotective effects in patients. In recently published work, the applicant identified MTMR5 (myotubularin-related phosphatase 5, encoded by the SBF1 transcript) as a potent neuronal autophagy suppressor in neurons. MTMR5 knockdown enhances the sensitivity of neurons to induction of autophagy, and accelerates the degradation of multiple autophagy substrates, including disease-associated and aggregate- prone proteins. In line with this, this proposal will test the central hypothesis that reducing MTMR5 in neurons augments autophagic clearance of ⍺-synuclein and reduces ⍺-synuclein-related neuronal death. The applicant will use human induced pluripotent stem cells (iPSCs) to determine if manipulating SBF1/MTMR5 enhances ⍺- synuclein turnover via autophagy (Aim 1) and modifies ⍺-synuclein proteotoxicity (Aim 2). He will also employ unbiased, genome-wide CRISPR-based screens to uncover key factors regulating MTMR5 in neurons (Aim 3). Collectively, these studies establish a novel research platform focusing on neuronal autophagy, myotubularin biology, and therapy design in PD and related neurodegenerative disorders.

NIH Research Projects · FY 2025 · 2023-05

Project Summary Neuronal signaling events at synapses determine circuit responses and result in specific behavioral outputs. This signaling is dynamic - modulated by the history of synaptic activity and perceived stimuli. Defects in neurotransmission also play a causative role in neurological disorders. However, our understanding of this process is limited by two factors: size and speed. Over the years, we have developed several techniques in electron microscopy to visualize changes in protein localization and synaptic ultrastructure associated with neuronal activity with millisecond temporal precision. Our experiments have revealed key insights into mechanisms of the synaptic vesicle cycle as well as new parameters controlling synaptic plasticity. However, many mysteries remain. How do exocytic and endocytic proteins coordinate to mediate membrane remodeling at synapses on a millisecond time scale? How do these proteins interact with each other and membrane lipids to perform their functions? How heterogenous are these processes? To address these questions, we will develop novel approaches in electron microscopy and leverage these tools to dissect the molecular mechanisms underlying synaptic vesicle exocytosis and endocytosis.

NIH Research Projects · FY 2026 · 2023-05

ABSTRACT I am finishing my cerebrovascular fellowship in the department of neurosurgery at the Johns Hopkins School of Medicine, where I will start as an assistant professor of neurosurgery with a practice focused on cerebrovascular diseases. I am applying for a mentored surgeon-scientist career development award (CDA) to obtain further training in neuroscience, immunology, and animal models of cerebral ischemia. This will further my long-term career goals of exploring neuro-immunologic mechanisms underlying cerebral ischemia, and hopefully provide a basis for new investigations in patients experiencing ischemic stroke. A major mechanism underlying stroke pathology involves neuroinflammation, where activation of microglia and infiltration of peripheral leukocytes worsen neuronal injury and cell death. Despite substantial pre- clinical efforts, there exists no efficacious therapeutic in limiting post-stroke neuroinflammatory damage. Mast cells are tissue specific, long-lived immunologic effector cells which are thought to be one of the first-responders in immune surveillance and activation, activating multiple pathways of the innate immune system. As such, the ability to suppress mast cell activation may broadly attenuate multiple pathways of cerebral inflammation after stroke. Recently, Mrgprb2 was identified as a mast cell-specific G-coupled protein receptor for basic secretagogues, mediating IgE-independent activation. I have shown preliminarily that deletion of Mrgprb2 results in decreased stroke volume after transient middle cerebral artery occlusion (tMCAO), with decreased transcription and production of TNFa and CCL2 after stroke, and decreased neutrophil recruitment into the ischemic brain. This CDA proposes building upon my pharmacology graduate training in mechanisms of cell death and cocaine addiction, towards a new direction at the interface of neuroscience and immunology. I hope this CDA will allow me to receive multidisciplinary training in the Departments of Neuroscience and Cellular and Molecular Medicine. Specific training goals include: (1) Training in advanced basic neuroscience techniques including dural and meningeal microdissection, and in-vivo live-animal imaging (2) Training in animal models of cerebral ischemia including photo-thrombotic stroke (3) Didactic and experimental training in immunology and neuro-immune interactions (4) Additional training in the ethical and responsible conduct of research. The research plan seeks to address the hypothesis that Mrgprb2 is a critical mast cell specific receptor which upregulates the initial immunologic activation response after cerebral ischemia, and that inhibition of the physiologic ligand for Mrgprb2 may decrease neuroinflammation after stroke. The Specific Aims of the proposal are to: (1) Investigate which subset of mast cell mediators are regulated by Mrgprb2 in ischemic stroke (2) Determine the localization and expression pattern of Mrgprb2 in central nervous system mast cells (3) Find the endogenous ligand for Mrgprb2 in cerebral ischemia by screening of known Mrgprb2 agonists after tMCAO, along with testing of inhibitors of Mrgprb2 as potential therapeutics of stroke.

NIH Research Projects · FY 2026 · 2023-05

Project summary/Abstract Hypoperfusion is broadly reported as an important symptom of Alzheimer’s disease related dementia (ADRD). Severity of cerebral blood flow (CBF) loss correlates with severity of cognitive deficit. However, hypoperfusion is only one of the signs of microvascular dysfunction in ADRD and, in fact, may not be the most sensitive or specific one. For example, in the recent NIH-funded MarkVCID Consortium study to identify the most sensitive biomarkers of vascular contributions to cognitive impairment and dementia (VCID), CBF was not selected as a candidate biomarker kit (despite proposed), whereas an index of vasodilatory function, referred to as cerebrovascular reactivity (CVR), was selected. In AD, despite the widely reported observations that there is hypoperfusion in posterior cingulate cortex and temporoparietal regions, some proposed this to be an indirect effect attributed to metabolic abnormalities via metabolism-vascular coupling. Therefore, to systematically understand the mechanism of hypoperfusion in ADRD, one needs to look beyond perfusion to examine a suite of related vascular and metabolic parameters in the brain. Therefore, the central goal of this application is to conduct a multi-parametric study to fully characterize the relationship between hypoperfusion and related vascular and metabolic underpinnings, separately in AD and small vessel disease (SVD) mice, as they represent two leading causes of dementia and most prominently linked to hypoperfusion. The proposed study in mouse models will parallel our ongoing efforts in human participants, making this work having a strong translational relevance. Using novel MRI techniques, we will measure CBF, cerebrovascular reactivity, oxygen extraction fraction, cerebral metabolic rate of oxygen, and BBB permeability concomitantly, and compare them to behavior (e.g. novel object recognition) and histology (e.g. smooth muscle cell density, tight-junction protein density) results (Aim 1). These multiple parameters will be integrated into a mechanistic model, which is fully testable based on the experimental measures proposed. The PI, an early stage investigator, is uniquely positioned to carry out this work because he has pioneered several of these MRI techniques in mice over the past few years. The non-invasive nature of these techniques (e.g. does not require skull thinning or contrast agents) also make them ideally suited for longitudinal studies (Aim 2), which will allow the characterization of the temporal relationship between hypoperfusion (and related vascular/metabolic parameters) and behavior outcomes. Two novel mouse models of Tau4RΔK-AP (replicating tauopathy and amyloidosis of AD) and CADASIL (replicating vascular pathology of SVD) will be utilized, based on the recent discovery of our collaborators. Taking together, we are in a unique position to make meaning contributions to the understanding of hypoperfusion in ADRD.

NIH Research Projects · FY 2026 · 2023-05

Project Summary An estimated 5.0 million children died before age 5 years globally in 2020. To improve child survival, the US government and international community invest in the development, evaluation and implementation of age- targeted, disease-specific life-saving childhood interventions, such as a malaria vaccine or azithromycin to address leading causes of under-five mortality including malaria, diarrhea, pneumonia and meningitis. Routine and timely estimates of age-and cause-specific under-five mortality (ACSU5M) are critical for understanding heterogeneity in causes of deaths within the under-five window and evaluating child survival policy and program effectiveness. ACSU5M estimates mandate precision well beyond what’s required to effectively target policies and programs in adults yet empirical data are scarce. Demographic and epidemiological evidence amounts to the conclusion that child cause of death is not uniform in the 1-59-month period. National empirical data at levels of specificity below 1-59 months are often not available in low resource settings with limited civil registration systems. Such data and estimates bear considerable scientific value to inform the development and impact evaluation of age-specific childhood interventions and their scale-up. Previous research has suffered from four main drawbacks: (i) using custom-collected data to understand age dynamics in a single cause; (ii) estimating ACSU5M only in broad age groups; (iii) ignoring uncertainty that arises from the empirical measurements of ACSU5M, such as prevalence measurement errors from routine household surveys; and (iv) failing to address cost effectiveness in data collection strategies. We leverage a team with extensive experience in both cause-specific and under-five mortality measurement and estimation to propose a series of Aims targeted at these drawbacks by specifically assessing and accounting for measurement errors to improve ACSU5M estimation in low-income countries. Our proposal evaluates data collection strategies through validation studies, focus group discussions and cluster randomized trials, and develops state-of-the-art statistical methodology to improve both the inputs into and the methodology behind ACSU5M estimation. Our statistical work builds on our ongoing NICHD R21HD095451 to develop a flexible Bayesian model which incorporates multiple sources of uncertainty using partial registration data. Partnerships with Country wide Mortality Surveillance for Action in Mozambique (COMSA-Mozambique) and the Matlab, Bangladesh Health and Demographic Surveillance System (HDSS) provide both infrastructure to evaluate and innovate on data collection strategies, high quality data for methodology development, and target end users for dissemination. If successful, the proposed study will further improve understanding of measurement errors in ACSU5M originated from major data collection strategies and significantly advance ACSU5M estimation to systematically address data scarcity issue so as to inform decision making to better child survival in low-income countries.