Johns Hopkins University

NIH Research Projects · FY 2025 · 2023-09

Project summary Malignant gliomas, including the most common type glioblastoma (GBM), are histologically heterogeneous and invasive tumors known as the most devastating neoplasms with high morbidity and mortality. Despite multimodal treatment including surgery, radiotherapy, and chemotherapy, the disease inevitably recurs and proves fatal. Local application of carmustine implants (Gliadel® wafers) as an adjunct to surgery and radiation therapy has been clinically proven to extend the survival time for patients with malignant gliomas, strongly suggesting that local chemotherapy after tumor resection presents a feasible and effective strategy to treat brain tumor patients. However, the rapid depletion of carmustine and low tissue penetration greatly limit the clinical benefits of Gliadel® wafers, which only extend the median survival of treated patients by six months compared to those untreated. This proposal aims to develop a novel type of self-assembling nanofiber hydrogels that use the anticancer drug camptothecin (CPT) as the molecular building blocks and that can be locally administered to the resection cavities after tumor removal, with the ultimate goal to achieve more effective treatments for patients diagnosed with malignant gliomas. We hypothesize that the proposed nanofiber hydrogels will spread across large tissue areas and sustainably release therapeutic agents for long-term cytotoxicity against glioma cells, thus leading to significantly extended survival time in our rodent model. To test our hypothesis, we outlined the proposed research activities in the three specific Aims, seeking to address the three key challenges in local delivery of therapeutic drugs into resection cavities: 1) the nanofiber gelation properties. The gel form enables prolonged retention in the delivery sites and also minimizes capillary loss of free drugs that would otherwise occur; 2) the sustained release of free drugs over a long period of time. The release rate and period are critical for effective elimination of glioma cells without causing devastating side effects; 3) diffusion across large tissue areas. In Aim 1, we will identify the key molecular parameters in the design of self-assembling CPT DAs to create CPT nanofibers of varying surface chemistries that would promote the formation of hydrogels upon contact with body fluids. Aim 2 is focused on the evaluation and fine-tuning of the drug release rate and mechanism, their ability to overcome the MDR mechanisms, as well as diffusion distance within organotypic tissues. In Aim 3, we will use an animal model to evaluate the nanofibers’ ability to diffuse across large tissue areas, pharmacokinetics, in vivo efficacy and toxicity of two already developed nanofiber hydrogels and also those to be developed in Aim 1 and Aim 2. Our ultimate goal is to develop a nanofiber hydrogel platform technology that will extend the survival time of rodents bearing human brain cancer, and translate this platform to a pre-clinical approach.

NIH Research Projects · FY 2025 · 2023-09

Deep learning (DL) based CT image formation methods have proliferated over the past few years. The existing approaches mostly follow the paradigm established in computer vision, and build a deep neural network (DNN) with standard modules that capture salient image features useful for computer vision tasks. These standard modules also work very well for CT images, placing DL-based CT image formation methods at the forefront of research and innovation. However, current DNNs are oblivious to the fact that CT images, unlike natural images, must be interpretable by a radiologist to make a diagnosis. CT image interpretation is affected by image features such as image resolution and noise variance-covariance, which are under exploited by the standard modules from computer vision. Consequently, current DL-based CT image formation has no direct characterization, let alone prospective control, of image resolution and noise variance-covariance. These properties can only be assessed after an image is generated, but resolution/noise has no direct influence during the image formation process. In this proposal, we challenge this established paradigm and propose an innovative DL framework named GradDNN to (1) characterize the resolution and noise properties of a DNN’s output during network training or parameter fine-tuning, and to (2) guide the image formation process so that the output has the desired resolution/noise properties. GradDNN (which stands for gradient + DNN) applies network linearization, i.e., gradient computation, to a mother DNN to extract local resolution and noise properties of the images generated by the mother, and make these properties available during network training and parameter fine tuning. The linearization method for analyzing nonlinear systems such as a DNN has never been attempted before. Conceptually, GradDNN associates a daughter module to any mother DNN for noise/resolution characterization, thereby making the resulting network CT-specific. We will develop GradDNN and demonstrate its capability in the context of two important clinical tasks: (1) mitigation of calcium blooming in coronary CT angiography, and (2) low contrast lesion detection in abdominal CT, both of which have high requirements on resolution and noise. Data for DL network training will be generated using digitally augmented patient data prospectively collected at two sites. Image quality comparison between the mother DNN alone and the mother+daughter duo, using a number of effective mother DNN architectures, will be carried out to demonstrate the additional gain of DL with joint resolution/noise learning. The comparison will use both digitally augmented patient data and real patient data to further establish robustness and generalizability. In this exploratory proposal, we focus on DL networks that perform image-to-image transformation. However, the learning framework using GradDNN is general and can be applied to DL networks that perform direct projection-to-image transformation. Successful completion of this proposal will generate strong preliminary data for a follow-up R01 that extends our results to such DL networks.

NIH Research Projects · FY 2025 · 2023-09

Project Summary This proposal focuses on the activation and utilization of dioxygen by heme and nonheme transition metal centers in metalloenzymes and in related synthetic systems. A subset of nonheme iron enzymes utilize a single iron center to activate dioxygen and mediate the oxidation of various substrates, including sulfur substrates as seen in thiol dioxygenases (TDOs) (e.g. cysteine dioxygenase (CDO)), persulfide dioxygenases (PDOs) (e.g. ethylmalonic encephalopathy protein (ETHE1)), sulfoxide synthases (e.g. EgtB, OvoA), and isopenicillin N synthase (IPNS). The related nonheme iron hydroxylases (e.g. TauD) and halogenases (e.g. SyrB2) also activate O2 with a single iron center to transform C-H bonds into C-X (X = OH, Cl) groups. Many questions remain regarding the mechanisms of action of these proteins, although the proposed pathways for these different enzymes include several common iron/oxygen intermediates. Heme enzymes also activate O2 for similar oxidative chemistry, such as C-H hydroxylation carried out by the monooxygenase cytochrome P450 (CYP), or the C-C bond cleavage and dioxygenation of indoles carried out by tryptophan and indoleamine dioxygenase (TDO/IDO). The proposed efforts involve the synthesis of biomimetic heme and nonheme iron complexes that will be used to examine how the first and second coordination spheres influence O2 activation and substrate oxidations. Efforts will be made to characterize metastable transition metal/O2 species (e.g. M-O2, M-OOH, M=O, M-OH) that are proposed as key intermediates in heme and nonheme O2 activation. Characterization of these species in structurally well-defined complexes will provide support for the analogous, putative intermediates in the enzymatic systems. The feasibility of key bond-making and bond-breaking events will be established by examining the reactivity of these metal/oxygen adducts with various substrates. Mechanistic questions will be addressed through comprehensive thermodynamic and kinetic studies. Systematic modifications will be made to these low molecular weight complexes through established synthetic methodologies, providing atomic-level control over their geometric/electronic structures. This approach provides a means to establish structure-function relationships that can be challenging or impossible to obtain when studying the enzymes alone. Questions to be addressed include what are the key intermediates during heme and nonheme iron activation of O2? What are the key spectroscopic features of these intermediates? Which of these species are capable of oxidizing which substrates? How does the structural and electronic properties of the ligands holding the metal center influence the O2 activation process? What controls the selectivity of substrate oxidations? Addressing these questions should lead to new knowledge regarding how heme and nonheme iron enzymes activate O2 and selectively oxidize substrates. These enzymes participate in biological processes that are essential for human health and disease, making them targets for both diagnostic and therapeutic treatments.

NIH Research Projects · FY 2026 · 2023-09

Global life expectancy is rising, and 16% of the world’s population – up to 25% in North America – is predicted to be at least 65 years of age by 2050. Aging societies are exposed to increasing emergence of age-related diseases such as Alzheimer’s Disease and related dementias (AD/ADRD). Identifying individuals at risk using new markers of pathophysiological changes will become a key challenge of 21st century medicine to enable prevention and early intervention. Establishing normative ranges of these markers across the lifespan is imperative for early diagnostics and to improve our understanding of healthy aging and AD mechanisms. Proton magnetic resonance spectroscopy (1H-MRS) is a non-invasive in-vivo method quantifying signals from endogenous metabolites, lipids and macromolecules (MM). MRS signal amplitudes are determined by the concentrations and MR relaxation times of these compounds, i.e. indicators of local biochemistry and cellular microstructure, respectively. Unfortunately, subject-specific metabolite relaxation and MM estimation is prohibitively time-consuming with conventional MRS methods, and researchers are forced to use averaged literature values and assumptions instead. This practice is highly problematic as changes in metabolite levels, relaxation times and the MM background reflect different biological processes that evolve independently across the lifespan, but cannot be distinguished using conventional MRS (e.g., signal decreases with age could reflect lower metabolite levels or shorter transverse relaxation times). Current MRS methods therefore have substantially diminished interpretability in healthy aging and neurodegenerative diseases such as ADRD. This research proposal will address this critical knowledge gap by developing novel MRS methods allowing simultaneous subject-specific metabolite concentration, relaxation time, and MM background estimation. By separating those three candidate biomarkers, a comprehensive profile of local neurochemistry and cellular microstructure with greater specificity than previously possible can be achieved. Application in a cohort of healthy volunteers between 20 and 80 years of age will establish age trajectories of the candidate biomarkers in normal aging. Developing these novel techniques requires substantial expertise both in MR sequence development and in data analysis. This proposal builds upon my exceptional record in developing our open-source MRS software package Osprey with new training in pulse sequence development from world-leading experts in the field. The Johns Hopkins University provides outstanding career development resources and training from world-renowned experts necessary to successfully mentor me in the field of MRS, pulse programming, and clinical research design in aging and AD/ADRD cohorts. This project will develop novel techniques to characterize important neurobiological processes and their role in healthy aging, laying the foundation to identify new early biomarkers of AD/ADRD.

NIH Research Projects · FY 2025 · 2023-09

PROJECT SUMMARY/ABSTRACT Each year, hundreds of millions of patients are exposed to general anesthesia for surgery. Millions of these patients are particularly vulnerable to injury during surgery because they are either very young (e.g., neonates and infants) or older (>70 years of age). One critical role of the anesthesiologist is to ensure hemodynamic stability and adequate organ perfusion (e.g., prevent intraoperative hypotension). When caring for patients at the extremes of age, this can be challenging because up to 80% of neonates, infants, and older adults experience intraoperative hypotension. This represents a significant public health problem as intraoperative hypotension has been shown to cause significant morbidity and mortality in this population and is associated with millions of dollars in additional healthcare costs per year. Though it is clear that intraoperative hypotension is a significant problem in neonates, infants, and older adults, the mechanisms that underlie the increased risk of intraoperative hypotension and its consequences remain unclear. To address this, we propose to use complementary in vitro and in vivo approaches to provide new insights into mechanisms by which patients at extremes of age suffer intraoperative hypotension with increased frequency. The goal of this research program is to investigate how the unique properties of the vasculature at the extremes of age contribute to the development of intraoperative hypotension in the setting of commonly used general anesthetics. Our published and preliminary data show that mesenteric arteries in juvenile rats are stiffer with diminished capacity to constrict to norepinephrine compared to adults. In contrast, middle cerebral arteries from juvenile rats demonstrated reduced stiffness and impaired autoregulation of cerebral blood flow when compared to adults. Taken together, these data provide the foundation upon which we hypothesize that the underlying mechanism of increased risk of intraoperative hypotension in patients at the extremes of age is vascular in origin. Over the next 5 years, we propose to investigate vascular mechanisms by which patients at the extremes of age are at increased risk of intraoperative hypotension and resultant organ hypoperfusion when exposed to general anesthesia. By studying isolated mesenteric and cerebral arteries we will identify biomechanical and cellular mechanisms that differentiate the very young and older adults from adults of intermediate age. Separately, we will use in vivo approaches to identify definitions of hypotension that are determined based upon organ perfusion. Finally, we will determine which anesthetic regimens are least likely to produce hypotension, and which therapies used to treat hypotension best balance improving blood pressure while preserving whole- body organ perfusion. These distinct but complementary lines of inquiry will be an important step towards optimizing perioperative care for those at the extremes of age.

NIH Research Projects · FY 2025 · 2023-09

ABSTRACT The overarching goal of the Pulmonary Rehabilitation to Reduce Post-Tuberculosis Morbidity (TB PuRe) project is to measure the effectiveness, feasibility, and cost-effectiveness of a pulmonary rehabilitation (PR) program to prevent post-tuberculosis (TB) respiratory morbidity in India. TB is associated with lung impairment which can persist despite successful completion of TB treatment. There are an estimated 155 million TB survivors globally, yet there are no routinely implemented interventions for addressing post-TB respiratory morbidity. PR is a key component of the management plan for chronic lung diseases and is an effective intervention to improve patient- centered outcomes. However, the clinical benefit of PR, administered during TB treatment, in preventing post- TB respiratory morbidity has not been investigated. Furthermore, despite the long natural history of TB disease and its disproportionate impact in resource limited settings, the feasibility of a home-based PR program for TB patients is unclear. Therefore, the aims of TB PuRe are: a) to measure the comparative-effectiveness of two home-based PR programs, administered during TB treatment, for preventing post-TB respiratory morbidity; b) to describe the intersection between clinic-level service organization, coach intervention delivery fidelity, and client behavioral action for these two PR programs; c) to compare the costs, cost-effectiveness, and budget impact of the two different PR strategies implemented as a routine program. To achieve these aims, 690 adult drug- sensitive pulmonary TB patients with functional impairment at TB treatment initiation will be enrolled at three geographically and epidemiologically diverse study sites in India. Participants will be randomized in 1:1:1 ratio into one of the following three study arms: a) 2 months of home-based PR during TB treatment (short PR arm); b) 2 months of home-based PR during TB treatment followed by 4 additional months of home-based PR for participants with persistent functional impairment despite 2 months of PR (extended PR arm); c) standard TB treatment without specific PR (standard-of-care arm). The primary outcome will be the 6-minute walk test distance compared between short and extended PR arms, and the standard-of-care arm at 12 months after randomization. We will assess the PR interventions' acceptability to inform adoption of the PR strategies in a programmatic setting by using the Theoretical Framework for Acceptability. Furthermore, we will empirically assess societal costs of the two PR programs at the patient-level, factoring the resource-use in the process of development of programmatic infrastructure, implementation, service delivery, and patient costs. Cost- effectiveness of the two programs will be assessed based on Health-related Quality of Life (HrQOL) outcomes assessment. Our study, if significant, will generate the strongest evidence to date to support routine implementation of a systematic PR program to reduce post-TB respiratory morbidity. Our multidisciplinary team with distinct, yet complementary, expertise and a strong track record of conducting NIH funded TB research in India will ensure the successful execution of the TB PuRe project.

NIH Research Projects · FY 2024 · 2023-09

Project Summary/Abstract The goal of this project is to increase an understanding of substance use, how it impacts HIV care, and how to address it in a critical population, female sex workers (FSW) aged 18 years and older, in South Africa (SA), using data and infrastructure from an ongoing adaptive intervention, the Siyaphambili trial. Mathematical models suggest that nearly half of the 200,000 annual HIV infections among adults in SA are acquired by FSW, their clients, or partners of their clients and thus treating these unmet needs could result in better health outcomes for women and the population as a whole. Specific Aim 1: Characterize substance use among the FSW living with HIV who participated in the Siyaphambili trial, with a focus on identifying temporal patterns of polysubstance use, using Latent Transition Analysis (LTA), their associated determinants (e.g., violence, stigma, economic vulnerability), and if they modify the effectiveness of the sequentially adaptive strategy to improve HIV care outcomes. Specific Aim 2: Conduct mixed methods formative research on how to deliver substance use treatment for FSW in the context of HIV care through semi-structured interviews with 200 FSW engaged in the Siyaphambili study or in the TB HIV Care (THC) treatment and prevention sex worker program who report any illicit drug use, to ascertain experiences with substances, treatment (e.g. types, relapse), willingness for treatment, and preferences for treatment using a discrete choice experiment. This data will be supplemented by in-depth interviews with 10 implementation partners (e.g., nurses, clinic management) recruited through our partnership with THC. Specific Aim 3: Organize an Implementation Development Workgroup to initiate crosstalk with domestic and international collaborators on substance in FSW to refine emergent implementation strategies for evaluation across contexts. This R21 will allow an additional focus on substance use in the Siyaphambili trial, including bringing on the additional content and methodological expertise needed to achieve the proposed aims. We will also collect primary data to inform the development and implementation of interventions that address substance use among FSW in the context of HIV care, as well as conduct activities that strengthen international collaborations working toward this end. The proposed R21 is aligned with multiple NIH OAR priorities, including reducing HIV incidence (through optimized treatment), has a high likelihood of success by leveraging an existing cohort, and will directly inform an R01 study on the implementation of substance use treatment and HIV care among this key population.

NIH Research Projects · FY 2025 · 2023-09

ABSTRACT The overarching goal of the Johns Hopkins O’Brien Center to Advance Kidney Health (JHOC) is to harness the collective expertise of basic, clinical and translational researchers at Johns Hopkins to serve as a national resource for investigators addressing the fundamental question of: what are the underlying mechanisms responsible for kidney diseases and how can they be mitigated? We will leverage the strengths and existing infrastructure of the Johns Hopkins Division of Nephrology and the Welch Center for Prevention, Epidemiology and Clinical Research. JHOC will include; 3 integrated cores (Administrative, Biomedical Resource and Resource Development); an Executive Committee; an Internal Advisory Committee, and a Community Advisory Board. Together, we will (1) provide an innovative portfolio of research services, resources, and tools for investigators to understand and ameliorate the burden of kidney disease; (2) develop new and refine existing resources as part of a dynamic incubator space for the conduct of basic and clinical research relevant to advancing kidney health; (3) transfer mature resources to the Biomedical Resource Core to be shared with the community; (4) plan and execute an annual Summer Student Enrichment Program which leverages a long- standing partnership with a Johns Hopkins program; (5) foster the careers of early-stage investigators by promoting multi-disciplinary and cross-sector collaboration that will attract investigators from fields not traditionally involved in kidney research; and (6) collaborate with the National Coordinating Center to prioritize external requests for resources and enhance national outreach. JHOC will support investigators conducting pre- clinical (basic), clinical or population health research addressing kidney disease, and will make recommendations to inform strategies, interventions, and approaches aimed at advancing kidney health.

NIH Research Projects · FY 2025 · 2023-09

PROJECT SUMMARY While the proteasome is typically known as protein degradation machinery, it is now recognized to have additional signaling functions in the nervous system. One poorly understood but therapeutically important role for the proteasome is in pain regulation in the peripheral nervous system (PNS). However, the relationship of proteasome activity to pain sensation is complex and somewhat paradoxical: proteasome inhibition has been found to either reduce pain or to cause pain sensitization and peripheral neuropathies depending on length of inhibition, type of inhibitor, and inhibitor dose. A recent discovery that may grant insight into this regulatory mechanism is our laboratory’s detection of a specialized, neuron-specific proteasome bound to the plasma membrane (NMP: neuronal membrane proteasome) that rapidly modulates activity-dependent neuronal calcium signaling through the release of extracellular signaling peptides. Preliminary data from our laboratory has demonstrated that NMP inhibition reduces dorsal root ganglion nociceptor activity and mechanical pain sensitivity, indicating that this novel neuronal communication pathway may be critical in proteasome/pain signaling. However, many fundamental questions about the NMP remain, including how it differs from cytosolic proteasomes and how variable NMP expression across neuronal sub-populations affects pain sensation. The central hypothesis of this proposal is that the PNS NMP plays an important role in pain signaling and that characteristics of NMP expression in PNS sensory neurons, including subtype-specific activity patterns and membrane localization patterns, directly affect its modulation of pain sensitization via differences in paracrine signaling. To address this hypothesis, we propose a series of biochemical, molecular, physiological, and behavioral assays addressing two specific aims: Aim 1. To determine the distribution and structure of the NMP in PNS neuronal membranes; and Aim 2. To investigate the role of the PNS NMP in diverse neuronal subtypes relevant to pain sensation. The completion of these aims will elucidate fundamental properties about the PNS NMP and provide insight into its regulatory role in pain sensation, identifying possible therapeutic avenues for pain modulation and laying the foundation for future investigations examining the role of the PNS NMP in health and disease.

NIH Research Projects · FY 2024 · 2023-09

Global life expectancy is rising, and 16% of the world’s population – up to 25% in North America – is predicted to be at least 65 years of age by 2050. Aging societies are exposed to increasing emergence of age-related diseases such as Alzheimer’s Disease and related dementias (AD/ADRD). Identifying individuals at risk using new markers of pathophysiological changes will become a key challenge of 21st century medicine to enable prevention and early intervention. Establishing normative ranges of these markers across the lifespan is imperative for early diagnostics and to improve our understanding of healthy aging and AD mechanisms. Proton magnetic resonance spectroscopy (1H-MRS) is a non-invasive in-vivo method quantifying signals from endogenous metabolites, lipids and macromolecules (MM). MRS signal amplitudes are determined by the concentrations and MR relaxation times of these compounds, i.e. indicators of local biochemistry and cellular microstructure, respectively. Unfortunately, subject-specific metabolite relaxation and MM estimation is prohibitively time-consuming with conventional MRS methods, and researchers are forced to use averaged literature values and assumptions instead. This practice is highly problematic as changes in metabolite levels, relaxation times and the MM background reflect different biological processes that evolve independently across the lifespan, but cannot be distinguished using conventional MRS (e.g., signal decreases with age could reflect lower metabolite levels or shorter transverse relaxation times). Current MRS methods therefore have substantially diminished interpretability in healthy aging and neurodegenerative diseases such as ADRD. This research proposal will address this critical knowledge gap by developing novel MRS methods allowing simultaneous subject-specific metabolite concentration, relaxation time, and MM background estimation. By separating those three candidate biomarkers, a comprehensive profile of local neurochemistry and cellular microstructure with greater specificity than previously possible can be achieved. Application in a cohort of healthy volunteers between 20 and 80 years of age will establish age trajectories of the candidate biomarkers in normal aging. Developing these novel techniques requires substantial expertise both in MR sequence development and in data analysis. This proposal builds upon my exceptional record in developing our open-source MRS software package Osprey with new training in pulse sequence development from world-leading experts in the field. The Johns Hopkins University provides outstanding career development resources and training from world-renowned experts necessary to successfully mentor me in the field of MRS, pulse programming, and clinical research design in aging and AD/ADRD cohorts. This project will develop novel techniques to characterize important neurobiological processes and their role in healthy aging, laying the foundation to identify new early biomarkers of AD/ADRD.

NIH Research Projects · FY 2025 · 2023-09

Project Summary/Abstract Understanding the spatial landscape of gene expression in tissues is a fundamental question for human health and disease. Applications range from identifying the spatial organization of cell types to dysregulation of spatial-dependent gene expression associated with disease. Advances in technologies, such as spatially-resolved transcriptomics (SRT), provide a wealth of data to investigate these questions. Furthermore, SRT combined with advances in long-read RNA-sequencing enable applications such as identifying spatial-dependent splicing variation and allele specificity in healthy and disease states, such as cancer or neurodegenerative disorders. Recent SRT studies are generating datasets across multiple samples (different donors or adjacent tissue sections), but researchers analyze samples independently because there lack computational tools for datasets with multiple samples. In contrast, when samples are jointly analyzed together, the statistical power is increased to detect differences with greater accuracy and precision. The lack of tools to analyze SRT data with multiple samples is a significant knowledge gap that limits are ability to refine the molecular causes and consequences of diseases that can be targeted for prevention and treatment. My research program develops scalable computational methods and open-source software for biomedical data analysis, in particular single-cell and spatial transcriptomics data, leading to an improved understanding of human health and disease. Here, our goal is to focus on developing scalable computational methods and software for data from spatial and long-read technologies with multiple samples and experimental conditions to accurately (1) predict spatial domains of tissues across multiple samples, (2) identify differences in spatial gene expression across experimental conditions or biological groups with multiple samples in each group, and (3) identify differential splicing variation across spatial domains or experimental conditions. The rationale for the proposed work is that the computational tools developed will enable substantial advances in our understanding of the spatial landscape of gene expression on distinct scales from cells to tissues to individuals. The significance of this proposal is substantial with broad impact for researchers increasingly using these imaging and genomic data, such as large-scale consortia generating spatial atlases across multiple samples, but also the proposed methods will be relevant to a wide variety of scientific disciplines that leverage high-dimensional data in a spatial context, such as environmental and mobile health. The project builds on my past experience in developing computational methods and open-source software for scalable clustering and identifying differences in gene expression at the single-cell level. The creation of well-documented, open-source software expands the impact of this work to other researchers aiming to understand the spatial landscape of gene expression in a variety of disease settings.

NIH Research Projects · FY 2024 · 2023-09

PROJECT SUMMARY / ABSTRACT Significance: Female sex workers (FSW) living with HIV are disproportionately marginalized and face a myriad of barriers to sustained engagement in HIV care and viral suppression. In 2022, South Africa remains the epicenter of HIV globally, and among FSW in the country, diverse experiences, vulnerabilities, and treatment outcomes exist. Tailored, multifactorial implementation strategies to support HIV care and viral suppression are needed for FSW whose needs are not being met, yet, it is not feasible nor effective to offer everything to everyone. Study Goal and Specific Aims: This study will provide a detailed understanding of when FSW engage with implementation strategies to support HIV care and treatment, who engages, as well as how implementation determinants influence outcomes, illuminating potential mechanisms for optimizing HIV treatment support strategies. Specific Aims are to: 1) Identify patterns of engagement among FSW living with HIV and determine their correlates and association with retention and viral suppression over time; 2) Explore how fidelity of strategy implementation (i.e., strategy dose administered) impacts the relationship between strategy exposure and clinical outcomes among FSW living with HIV; and 3) Characterize contextual factors influencing strategy implementation and the effect on retention and viral suppression among FSW living with HIV. Approach: This study will leverage existing quantitative, qualitative, and implementation data and infrastructure of the Siyaphambili trial. The Siyaphambili study employed a sequential multiple assignment randomized trial to test two implementation strategies among a cohort of 777 non-virally suppressed FSW living with HIV over an 18-month follow-up period. The proposed study utilizes group-based trajectory modeling to identify distinct trajectories of longitudinal FSW engagement (Aim 1), a component path analysis to explore the role of programmatic implementation fidelity (Aim 2), and a moderator analysis to characterize implementation determinants, interpreted and contextualized through in-depth interviews (Aim 3). All proposed Aims represent novel analyses of existing, cleaned data collected from the Siyaphambili study. Fellowship information: The proposed research is the doctoral dissertation of Ms. Carly Comins. The training plan consists of selected coursework, tailored ongoing mentorship, and professional development to foster the successful completion of the proposed research and to prepare Ms. Comins to become an independent HIV epidemiologist and implementation scientist supporting HIV-related implementation research for key populations. The proposed study directly aligns with the NIMH’s goals and the priorities of the Division of AIDS Research, including leveraging pragmatic effectiveness-implementation research to enhance understanding of the real-world impact of evidence-based interventions; improving methods to match interventions to marginalized populations; and optimizing the delivery and reach of interventions among those at greatest need.

NIH Research Projects · FY 2025 · 2023-09

Project Summary Restoration of soft tissue is a significant challenge facing clinicians. The available reparative options, whether prosthetic or autologous, present major drawbacks including donor site defects, unpredictable tissue survival, limited duration of restoration, prosthetic exposure, infection, and fibrosis. Therefore, a critical need exists for a solution which can replace missing tissue volume while encouraging natural remodeling of soft tissue over time. We have recently developed an injectable nanofiber-hydrogel composite (NHC) material which is capable of inducing remodeling of the injected volume into vascularized soft tissue with adipocytes without relying on exogenous growth factors and cells. However, the mechanisms by which it does so are not yet well understood. The goal of this proposed project is to characterize the immune and tissue remodeling kinetics of the injected NHC material, uncover the mechanism(s) by which it achieves soft tissue remodeling, and optimize its formulation to enhance this desired outcome. We will first investigate the local immune and tissue remodeling kinetics of the injected site caused by the NHC. This will include characterizing cell infiltration, healthy extracellular matrix (ECM) deposition vs. irregular fibrosis and foreign body response, inflammation, angiogenesis, and adipogenesis. In addition, we will uncover the NHC’s mechanism of instigating soft tissue remodeling by carrying out single-cell RNA sequencing to identify candidate cell subtypes and activated signaling pathways and then subsequently confirm them through immune knockout or targeted depletion models to establish a causal relationship. Gaining insight into how soft tissue remodeling can be accomplished with this biomaterial system will have wide-reaching implications for the regenerative medicine field as we work towards creating off-the-shelf biomaterials-based solutions for tissue replacement. Finally, through modulation of physical and structural properties as well as leveraging our mechanistic understanding, we will optimize the parameters of the NHC to maximize desired soft tissue remodeling. If successful, this proposal will produce an improved off- the-shelf biostimulatory NHC with enhanced capacity to achieve natural tissue restoration outcomes as well as a mechanistic understanding of how to achieve soft tissue remodeling, thereby expanding the ability to treat patients and allowing scientists to engineer the next generation of biomaterials for tissue replacement.

NIH Research Projects · FY 2024 · 2023-09

Project Summary: Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly and is driven by multiple genetic and environmental factors that lead to severe loss of central vision. However, no definitive treatment options are available for the dry form of the disease. Inflammation has been known to play an important role in maintaining tissue homeostasis. However, a deregulated inflammatory response is associated with tissue damage and the onset of several aging diseases, including AMD. Even though several studies have demonstrated the role of inflammation in AMD pathogenesis, the underlying mechanism controlling the inflammatory cascades, particularly driving the onset of chronic inflammation in AMD, still remains unknown. We have recently reported the novel finding that in dry AMD patients9,10 and in a mouse model of dry AMD, there is inflammation induction due to the activation of Akt2 signaling in the retinal pigment epithelial (RPE) cells-the first cells affected in dry AMD. Importantly, Akt2 inhibition in this mouse model reduced retinal inflammation and alleviated early RPE changes. Additionally, AMD patients also have increased Akt2 levels in the macular RPE cells relative to controls. Therefore, to evaluate the role of Akt2 activation in RPE health and in retinal degeneration, we have generated RPE-specific Best1 (Akt2) constitutive knock-in (KI) mice. These mice show a dry AMD-like phenotype, as evident from basal laminar deposits, decreased ezrin expression, hyperpigmentation, and morphological alterations in the RPE, as well as decreased retinal function. We propose to use this mouse model and iPSC-derived RPE from CFH(Y/Y) [controls] and CFH(H/H) [AMD risk allele containing] donors as novel tools in this study for testing our central hypothesis that “activation of Akt2 signaling in the RPE triggers mitochondrial/autophagy dysfunction leading to oxidative stress and inflammation, which are critical factors in early AMD pathogenesis”. To address this hypothesis, we propose the following aims: Specific Aim 1 (mentored phase): To test our hypothesis that Akt2 overexpression in the RPE elicits mitochondrial/mitophagy dysfunction thereby inducing oxidative stress; Specific Aim 2 (mentored phase): To test our hypothesis that activation of Akt2 in the RPE drives retinal inflammation; Specific Aim 3 (independent phase): To test our hypothesis that the molecular cascades associated with autophagy-mediated regulation of inflammation are critical in AMD pathogenesis. The proposed study is significant because we will use a unique, state-of-the-art in vivo animal model and extend our studies to human iPSC-derived RPE samples to investigate how inflammation contributes to vision loss in AMD and develop strategies potentially leading to a new treatment modality for early, dry AMD.

NIH Research Projects · FY 2025 · 2023-09

PROJECT SUMMARY Pancreatic ductal adenocarcinoma (PDAC) is uniquely difficult to treat due to late diagnosis and limited medical management options for a majority of patients. This is despite a wealth of watershed studies on disease driver mechanisms over the past decade, highlighting a need for alternative approaches to studying this disease. It is now clear that PDACs present along a bimodal continuum of transcriptomic subtypes that exhibit distinct prognoses, and additional work on advanced PDAC models has uncovered that these tumors, though highly chemoresistant, are sensitive to external amino acid supply through metabolic dysregulation. Transcripts that define known PDAC molecular subtypes present unique codon biases, suggesting that PDACs are subject to biologically deterministic codon-level selective pressures. Work from our lab and others has shown that the abundance of properly aminoacylated transfer RNAs (tRNAs), highly structured and chemically modified non- coding RNAs, is highly deterministic of mRNA half-life. This mechanism acts through codon-anticodon recognition and ribosome elongation rate, and alterations of functional tRNA abundance can dictate cellular functions via concomitant regulation of mRNA stability. Furthermore, a wealth of literature evidence in diverse cell types across species demonstrates that tRNA regulation can be disease-specific. Thus, tRNAs may likely serve a key regulatory role in PDAC subtype expression and amino acid sensitivity, given their function in bridging codon-amino acid pairings during protein production. As proof of concept, I have strong preliminary evidence that tRNA expression can be highly predictive of disease stage in a limited cohort of primary colorectal tumor samples. Furthermore, a pilot study of PDACs revealed widespread tRNA dysregulation, with increased use of cysteine-decoding transcripts, matching existing literature that PDACs are specifically sensitive to deprivation of this amino acid. In this proposal, I seek to interrogate linked roles of tRNAs as regulators of mRNA and nutrient availability phenotypes in PDAC. My central hypothesis is that PDACs specifically regulate tRNA expression to confer cell survival and proliferation advantages and that tRNA profiling can reveal novel biomarkers for use in clinical decision-making. I will address this hypothesis through the following aims: Aim 1: Characterize tRNA expression and modifications in primary patient PDACs; Aim 2: Investigate PDAC tRNA regulation as a driver of tumor cell survival. These aims will be achieved through a combination of biochemical and high-throughput sequencing approaches using archived patient samples and established in vitro cell lines. Beyond biological interrogation, this proposal involves novel technical development in the experimental and analytical application of tRNA sequencing for large patient sample cohorts. This project would be the first to analyze tRNA gene-specific regulation in cancer, and will be significant in that it may reveal novel targetable mechanisms of PDAC maintenance and a potent set of disease-associated clinical features that are likely to inform fundamental cancer biology.

NIH Research Projects · FY 2025 · 2023-09

Center for Innovative Research, Capacity Building and Leadership Development to End Substance Use Harms (CIRCLE) Drug and alcohol use related health problems and overdose deaths disproportionately impact quality and longevity of life for many American Indian and Alaska Native (AI/AN) communities. The Center for Innovative Research, Capacity Building and Leadership Development to End Substance Use Harms (CIRCLE) P50 aims to address drug use related health problems in collaboration with AI/AN communities. Through research, training, and outreach, we will respond to calls for enhanced focus on recovery and prevention, sources of strength, and policy solutions. The P50 Cores and Research Projects will operate with emphasis on four cross-cutting domains: 1) Substance Use Research Leadership; 2) Community/Tribally Based Participatory Research (C/TBPR); 3) Precision Public Health; and 4) Centering Community Strengths. Reflecting these thematic approaches, the Center's overarching aims include conducting impact-focused C/TBPR to identify substance use risk and protective factors and intervention effects across distinct contexts. We will also foster the development of junior scholars to expand capacity and innovation in research, practice, and policy surrounding alcohol and drug use. We further aim to expand and deepen our engagement with educational facilities, researchers, Tribal and Urban American Indian communities, policy makers, and the public to serve as a national resource for more rapid uptake and sharing of novel methods, measures, and programs in service to reducing drug use harms. To achieve these goals, the Center will house the following: 1) Administrative Core to oversee management, administrative structures, scientific priorities, and training activities; 2) Research Core to provide methodological expertise to support the research of the Center; 3) Pilot Project Core to support innovation in drug use research, and 4) Three Research Projects that will conduct multidisciplinary and synergistic science focused on drug use prevention, intervention, and policy.

NIH Research Projects · FY 2025 · 2023-09

PROJECT SUMMARY This project intends to increase adult immunization through an evidence-based Quality Improvement (QI) program that combines adult-specific approaches across healthcare provider settings. We will improve understanding of current adult QI activities, develop an Adult Immunization QI Program (Adult IQIP), and implement, support, monitor, evaluate and disseminate our Adult IQIP program.

NIH Research Projects · FY 2024 · 2023-09

PROJECT SUMMARY Activation of sensory nerves, in particular nociceptive C-fibers, is a feature of most respiratory viruses. Evidence of such activation is found in the classical consequences of C-fiber activation including sneezing, sore throat, coughing, and reflex secretions. As well as causing the troubling symptoms of viral infection, the activation of these nerves allows viruses to escape the body and be transmitted to other hosts, i.e. nociceptor activation amplifies viral spread in a community. In addition, activation of airway vagal C-fibers can lead to strong reflex bronchoconstriction and excessive secretions that likely contribute to the exacerbation of asthma particularly in children. Given the relevance to human disease, surprisingly little is known about how virus infection induces C-fiber activation and sensitization. In theory, viral infection leads to C-fiber activation by two general mechanisms. The first is that viral infection of epithelial cells leads to the production of a mediator(s) that stimulates the C-fiber terminals. The second is that the virus itself directly activates the nerves. This second mechanism will likely be dependent on the specific virus type. This proposal focuses on this second (direct) mechanism of activation as it relates to coronaviruses. I hypothesize that the coronavirus spike protein interacts directly with C-fiber terminals in a manner that activates and sensitizes the nociceptive C-fibers. My preliminary data, using three orthogonal approaches, support the conclusion that the spike protein directly activates (evokes action potential discharge) about 40- 50% of vagal C-fibers in mouse airways. My first aim is to characterize the subtype of vagal C-fibers that are activated by spike protein and also to assess whether the spike protein, short of overt activation, leads to the sensitization of C-fiber terminals, i.e. renders them more sensitive to other activating stimuli. My second aim focuses on the mechanism. I hypothesize that this interaction involves the galactin-3 fold in the spike protein, and occurs independently of the spike protein receptor ACE2 or toll-like receptors. Irrespective of the proximal binding target, I will address our hypothesis that activation is secondary to the opening of TRPV1 and or TRPA1 channels. These aims will be addressed using single cell RT-PCR analysis of mRNA expression in airway specific nociceptive C-fibers, extracellular and patch-clamp electrophysiology, and 2-photon live imaging techniques. The results of the studies are expected to provide insights into a novel mechanism of coronavirus induced airway C-fiber activation.

NIH Research Projects · FY 2024 · 2023-09

PROJECT SUMMARY/ABSTRACT Low-income older adults (LIOA) are a population at higher risk to develop Alzheimer's disease and related dementias (ADRD) and sleep disturbances. Although empirical research suggests that physical activity interventions benefit cognition and sleep in older adults in general, the possible benefit of physical activity is understudied in LIOA. The available evidence in LIOA suggests that LIOA experience unique barriers to physical activity, more prevalent physical inactivity and sedentary behaviors. Since physical inactivity and sedentary behaviors are independent risk factors that have synergistic harmful effects for cognitive function and sleep, it is crucial to address them simultaneously to promote cognitive and sleep health in LIOA. The growing wearable device and mobile Health (mHealth) provide an innovative approach to deliver individually tailored physical activity interventions at home with flexible schedules to overcome barriers to physical activity in LIOA. In addition, limited research has examined if physical activity interventions impact the individual’s Amyloid/Tau/ Neurodegeneration (ATN) Alzheimer's disease biological state and whether physical activity may promote cognition through impacting sleep and AD pathology. This randomized controlled trial is designed to examine the immediate and sustaining efficacy of an mHealth-facilitated Physical Activity Toward Health (mPATH) intervention on cognitive function and sleep in LIOA. mPATH is a personalized physical activity intervention that includes personalized physical activity plans and training sessions, exercise at home by following personalized exercise videos, and biweekly phone coaching over 24 weeks, supported by wearable devices-enabled mHealth strategies. mHealth strategies and exercise videos will be used to support participant’s physical activity during 6-12months. In the proposed study, we will randomize 176 community dwelling LIOA with insomnia symptoms and without dementia to the mPATH or control group on a 1:1 ratio. Randomization will be stratified by age, sex, and cognitive status. Specifically, we will (1) test the immediate (6- month) and sustaining (12-month) effects of mPATH on cognitive function among LIOA, compared to control; (2) test the immediate (6-month) and sustaining (12-month) effects of mPATH on sleep, compared to control; and (3) explore the effect of mPATH on ATN biomarkers and potential mediating roles of sleep and ATN biomarkers in mPATH’s effect on episodic memory.

NIH Research Projects · FY 2025 · 2023-09

ABSTRACT Social, emotional, and behavioral (SEB) problems are among the most common chronic disabilities affecting children growing up in urban and rural poverty. They also have implications for children’s school success as they affect essential social-emotional learning skills such as the ability to comply with rules, follow instructions, regulate emotions, and get along with others. These essential skills are first learned before kindergarten (K) entry, in the context of a supportive, responsive, and consistent parenting relationship. To date, universal school-based interventions to improve young children’s social-emotional learning have primarily targeted students and teachers. Yet, parents are the central figures in young children’s lives and they need to be equal partners with schools in promoting SEB skills. This study seeks to improve children’s SEB competence and K readiness by strengthening parent engagement and parenting skills in early childhood education during prekindergarten (PreK). This hybrid Type 2 effectiveness-implementation trial will rigorously evaluate the effects of an evidence-based parenting program, called the Chicago Parent Program (CPP), implemented in PreK on K outcomes in urban and rural Title 1 schools in Maryland. Effectiveness Aims: Using a cluster randomized design (N=30 schools, 840 families; >90% low-income), we will examine the effects of CPP offered universally to Title 1 PreK parents on a) children’s SEB competence, parent engagement, and parenting skills; and b) K readiness, chronic absence, and grade retention in K. We will also examine the mechanisms underlying those effects. Schools will be stratified by rural vs urban district then randomized to experimental (CPP) or control (usual practice) conditions. Data will be collected from multiple informants (parents, teachers, CPP group leaders, school personnel, district administrative data). Implementation Aim: Using the RE-AIM framework and a mixed methods approach, we will assess CPP reach, effectiveness, acceptability, adoption, implementation, cost-effectiveness, and sustainability when offered in different formats (virtual CPP groups vs in-person CPP groups) and contexts (urban vs rural schools). Schools will participate for 2 years with experimental schools offering CPP twice, once in a virtual group format and once in an in-person group format (format counterbalanced), giving us the ability to compare a range of outcomes associated with uptake, acceptability, cost, and sustainability by CPP format in low-resource rural and urban contexts. This study addresses the NICHD priority to test developmentally informed interventions designed to ameliorate early adverse environmental effects on children and optimize their growth, development, and SEB wellbeing.

NIH Research Projects · FY 2025 · 2023-09

Hearing loss affects people across the whole population and covers two broad spectra: first, the degree of loss, ranging from hard of hearing (correctable with hearing aids) to profound (which often can be mitigated with cochlear implants); and second, etiology which can be congenital, progressive, late-onset, age-related or acquired. Each of these factors can affect the extent of the challenges faced by people with hearing loss, but all hearing loss affects communication – and therefore socialization - to some degree. Significant technological advances over the past 20 years have greatly improved the capacity of people with hearing loss to listen and speak; improved hearing increases information received and, with training, children with hearing loss can learn to listen, speak and participate in all activities. In this R25 proposal, Johns Hopkins University (JHU) will implement a multi-institutional distributed mentoring model called STEMM-HEAR. The successful development of this model will be a template for other university programs and guide research leaders in providing impactful hearing sciences research experiences. The program encourages students and mentors with lived experience in hearing loss to develop improved capabilities needed to maximize their potential in STEMM. The model will accelerate the recruitment of students into careers in STEMM, including the hearing sciences. JHU will work with professional and educational organizations to disseminate program opportunities to work in hearing sciences laboratories at Oregon Health & Science University, University of Southern California, Creighton University, Rice University, Stanford University, and University of Minnesota. By participating in summer internship programs at these institutions, the students will acquire and share research experiences via a peer network mentoring program within a community of scientists and engineers in hearing sciences and research.

NIH Research Projects · FY 2024 · 2023-09

PROJECT SUMMARY/ABSTRACT Among the “big three” infectious diseases worldwide, malaria stands out for the complexity of the Plasmodium life-cycle and biology. Malaria parasites breed mainly within red blood cells, and across their lifespan there are dramatic shifts in protein expression and metabolism that alter their appearance, behavior, and susceptibility to clearance by the host immune system or antimalarial drugs. Because it is an infection of the blood, a biopsy can be taken with a simple finger prick, and the ability to derive histopathological information via light microscopy is a critical tool in the study of, and ultimately control and treatment of, malaria. Manual review is painstaking and imperfect. Neural network-based computer vision (CV) approaches can accelerate data acquisition from light microscopy and innovate new methods of extracting data currently only possible through costly, labor-intensive benchtop molecular methods or time-consuming review by a small number of malaria microscopy experts with the necessary training and experience to distinguish subtle differences between parasite forms. This R21 proposal builds on 12 months of preparatory work supported by a pilot grant from The Johns Hopkins University Institute for Data Intensive Engineering and Science, a collaborative pursuit of the Schools of Medicine and Engineering. The co-principal investigators developed a deep learning-based CV algorithm trained on a public dataset of >10,000 images of Plasmodium falciparum ring stage parasites that can detect and quantify parasites with >0.97 accuracy. However, significantly more information is ripe for extraction from malaria smears beyond the simple detection of parasites. We built an early prototype of a 2nd-generation CV algorithm capable of identifying the correct parasite stage to the level of early, middle or late ring stage with >0.80 accuracy, and in this proposal we aim to refine the performance and extend the capabilities of the malaria CV system to wider applications while pioneering new computational methods in multiple domain adaptation and weakly- and semi-supervised learning. The proposed project would result in the development of a next-generation malaria CV system that can derive molecular data from brightfield images for use by investigators at the bench or in the clinic. We will build out the prototype CV system to optimize performance, develop higher-order classifiers (e.g., differentiating viable from nonviable circulating parasites, finding once-infected cells for the prognosis of delayed hemolysis after treatment), and run the algorithm against different tissue backgrounds (e.g., liver, spleen). The product of this work will be a cutting-edge neural network-based malaria CV system that provides a multiplex readout of parasite biological parameters and cellular pathology to help propel the fields of malaria research and biomedical CV analysis forward.

NIH Research Projects · FY 2025 · 2023-09

PROJECT SUMMARY HIV remains the leading cause of death among adults in South Africa despite the availability of antiretroviral therapy (ART) due to failure to initiate ART and failure to remain on ART. Gaps in HIV care are especially prominent among key populations at high risk for both HIV and reduced use of HIV services. One population with an HIV prevalence double the age and sex-matched general population (23%) and with low engagement in HIV care is individuals recently released from incarceration. During incarceration >90% initiate ART; following reentry into the community only 34% remain in care. The transition from the controlled carceral environment and its restricted autonomy to life in the community requires reestablishing planning skills, self- efficacy, and social support and overcoming bureaucratic barriers to accessing community clinics. We have demonstrated that an intervention that circumvents clinic barriers by directly providing ART and builds behavioral skills through peer-facilitator led group sessions improves care continuity following release from incarceration. In a pilot study of this intervention supported by NIMH, termed SPARCS, among 176 participants, 36% of those in the care as usual compared to 61% of those in the intervention arm were in-care 6 months after corrections release. These results raise important questions regarding possibility of programmatic scale-up. Scale-up requires achieving a balance between effectiveness, feasibility, and cost. Notably, the tension between effectiveness and feasibility may require reducing overall effectiveness – such as by eliminating a component of SPARCS – to increase feasibility. To explore each of these questions, we are proposing a hybrid type I effectiveness-implementation study structed with the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation, Maintenance). First, we are proposing a 2x2 factorial design to maximize power of a randomized controlled trial of the Full-SPARCS intervention and the two distinct components termed “ART-SPARCS” and “Group-SPARCS” and usual care, to test for a difference in viral load suppression 6 months from correctional facility release. Second, we propose characterize implementation in terms of reach, adoption or adoption potential, acceptability, and fidelity. Finally, will use findings from the RCT to inform costing and cost-effectiveness to inform policy makers regarding cost of SPARCS and components and cost-effectiveness of each component and the full SPARCS to inform implementation cost and potential long-term sustainability or maintenance. This project has the potential to generate considerable new knowledge on interventions that can improve care continuity for this population and key findings for potential scale-up relevant to policy makers. This proposed study has the potential to generate actionable knowledge to improve outcomes for community reentrants and contribute to overall goals of HIV epidemic control.

NIH Research Projects · FY 2025 · 2023-09

Alzheimer’s disease (AD) is a debilitating neurodegenerative condition affecting approximately 6.7 million people in the US aged 65 and older. Individuals with AD experience progressive memory loss and profound atrophy of the hippocampus, the seat of learning and memory in the central nervous system (CNS). Currently there is no cure for AD, and the percentage of affected US citizens is predicted to grow given our steadily aging population. Although neuronal death is prominent in AD, non-neuronal glial cells have been shown to be key players in AD pathogenesis, as they influence the microenvironment, provide metabolic support, and control inflammation. Nevertheless, the precise roles of different glial cell types in hippocampal aging and AD disease progression remain to be defined. Recent evidence indicates that a ubiquitous population of glial progenitor cells, termed oligodendrocyte precursor cells (OPCs) or NG2+ glia, control the extracellular matrix, engulf neuronal processes and present antigen through major histocompatibility complex I and II, and exhibit reactive behavior in disease, suggesting that they may modify the integration and survival of neurons in the brain. Although OPCs give rise to oligodendrocytes in the developing and adult CNS, they persist throughout life and may play important non-progenitor roles. Importantly, transcriptional analysis of OPCs indicate that they take on a unique molecular signature in AD; however, we have only a limited understanding of the impact of OPCs on neural circuit remodeling. An understanding of the mechanisms governing their role in promoting the integration and survival of neurons could reveal their unique role in neurodegeneration. To study the role of OPCs in circuit remodeling in the healthy and diseased brain, I plan to define the role of OPCs in two regions of neuronal integration that persist into adulthood: the stratum lucidum (SL) of the hippocampus (a key site of AD pathogenesis) and the olfactory bulb (OB). My preliminary analyses reveal that OPCs are denser and exhibit a unique morphology and transcriptional profile within the SL, where newly born dentate gyrus granule cells project their axons to area CA3, and within the OB, where neurons arriving from the rostral migratory stream integrate. These findings provide the motivation to explore the distinct features of OPCs in these regions and their involvement in circuit reorganization. I will test the central hypothesis that OPCs facilitate the integration of newly born neurons in the adult CNS and alter neuronal survival in AD. I will define the phenotype of OPCs in areas of active neuronal remodeling through in vivo imaging and scRNA-Seq; I will quantify the role of OPCs in circuit remodeling across aging, exercise, and neurodegeneration (specifically an AD mouse model); and I will genetically manipulate OPCs and determine the effect these manipulations have on neuronal integration. Through these studies, I hope to define the role of OPC-neuron interactions in structural remodeling of neurons in the mature CNS. Understanding the role of OPCs in the development and maintenance of neuronal connectivity could have important implications for brain development, repair, and survival of hippocampal neurons in AD.

NIH Research Projects · FY 2024 · 2023-09

PROJECT SUMMARY Pulmonary hypertension (PH) is a highly morbid disease with numerous causes but limited therapies. The avail- able medications are only known to be safe and effective for patients with very specific forms of PH. Recently, an inhaled medication, treprostinil, was approved for the treatment of PH related to interstitial lung disease (PH- ILD). Most PH-ILD studies have either focused on patients with idiopathic pulmonary fibrosis or ILD as an all- inclusive diagnosis. However, the various forms of ILD are distinct in their underlying pathophysiology and af- fected patient populations. Connective tissue disease-related ILD (CTD-ILD) is an understudied form of ILD which tends to affect young, ethnically diverse, female patients. The intersection of PH and CTD-ILD is particu- larly challenging as the PH may arise through fibrosis-induced ablation of pulmonary blood vessels or from endovascular dysfunction driven by the chronic inflammation of CTD. At this time, determining which mechanism underlies an individual CTD-ILD patient’s PH is left to the discretion of clinicians who must also decide which treatments to use based on their decision. These decisions are usually guided by subjective assessments of the degree of fibrosis seen on chest imaging (e.g., computed tomography [CT]), the severity of restrictive ventilatory defect measured during pulmonary function testing (PFT), and invasive hemodynamic measurements. In this proposal, I will use a CT- and PFT-based severity staging system which was validated in patients with sclero- derma ILD, to classify patients with CTD-ILD and PH as having either a parenchymal or vascular phenotype. When I applied this system to 20 patients in the Johns Hopkins PH Center Registry, 35% of these patients were reclassified and had received therapies discordant with their phenotype. To investigate the implications of these preliminary findings, I will leverage the Johns Hopkins PH, ILD, and Myositis Centers’ registries to phenotype patients with CTD-ILD-related PH (CTD-ILD-PH). My first aim is to determine the proportion of CTD-ILD-PH patients with parenchymal and vascular phenotypes and compare disease severity between phenotypes at the time of diagnosis. For this aim, I will compare various measures of disease severity collected at the time of PH diagnosis for patients currently and prospectively enrolled in our registries. These measures will include global and symptom-specific quality of life questionnaires, 6-minute walk distances, WHO functional class, and hemodynamic assessments by echocardiography, serum NT-pro-BNP levels, and right heart catheterization. Second, to compare the clinical outcomes of CTD-ILD-PH patients who receive phenotype-concordant therapy with those who receive phenotype-discordant therapy, I will compare the clinical measures de- scribed above before and after four to six months of PH therapy. Results from this study will provide data to inform future studies of PH therapies for patients with the parenchymal and vascular phenotypes of CTD-ILD- PH and serve as a strong foundation for a future K-level award.