Grants

National Park Service

United State Department of the Interior, National Park Service (NPS) Notice of Intent to Award. This is not a request for applications. This posting is to provide public notice of NPS' intention to fund the following project activities without full and open competition: Task Agreement P14AC01344 under Cooperative Agreement H8W07110001 with the Alaska Department of Fish and Game, a partner under the Pacific Northwest Cooperative Ecosystem Studies Unit, for the project titled, "Determining Moose and Wolf Population Estimates for the International Chisana Caribou Herd Management Plan."

$55K

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Determining Optimal Foot Shape Capture Methods to Prioritize Offloading in An Accommodative Insole

NIH

Custom accommodative insoles are prescribed to patients with diabetes who are at risk of developing plantar ulcers. Custom insoles aim to reduce plantar pressures through an accommodating insole with a weight-bearing surface that conforms to the patient’s foot. The current standard of care (SoC) insoles are typically constructed from an EVA foam block milled to match a patient’s foot shape, captured via a foam crush box, and then covered with a uniform sheet of poron and plastazote foam. The material properties of these insoles are generic and not patient specific. We have developed insoles that not only have patient specific shape but also patient specific regions of modulated stiffness. Our insoles are more effective in reducing plantar pressure in the areas of high pressure than the current SoC insoles in a healthy population and investigation is underway with similar preliminary results in individuals at risk of developing a plantar ulcer. Our work suggests that both foot shape and plantar pressure are important factors when designing accommodative insoles and offer the clinician a new tool to better customize the insole to the patient’s specific needs. Clinically, direct foot-shape scanners are already being implemented. However, it is critical to understand if these scanners distort the shape of the foot compared to the traditional foam crush box and how reliable the various scanning methods are within and across clinicians. Evaluations of intra-rater reliability of basic measures of foot shape (i.e., length and width) have been conducted, however, more comprehensive methods evaluating the plantar surface such as arch volume and overall surface differences are critical when designing an insole, given that the insole must conform to the foot shape. Thus, the purpose of this proposal is to evaluate the methods for obtaining shape and their effects on accommodative insole design and the ability to offload high-pressure areas in people with diabetes. Additionally, plantar pressure is not incorporated into the clinical design of SoC insoles. Compared to our current in-shoe pressure capture method, barefoot walking plantar pressure is a much more practical metric for clinicians to obtain. In this project, we will also determine if designing insoles with barefoot or in-shoe plantar pressure yields similar reductions in plantar pressure. Aim 1a: Quantify the inter- and intra-clinician reliability of three methods of capturing foot shape (crush box, Tiger scanner, structure sensor). Aim 1b: Quantify the differences in foot shape obtained using three methods of capturing foot shape. Aim 2: Evaluate the ability of insoles designed using the various foot scanning methods to offload areas of high pressure in the diabetic foot. Methods: Aims 1a and b: Three clinicians will take three shape measurements of the feet of ten healthy individuals with each of the following foot shape capture devices. Standard 1-D measurements and more comprehensive methods of evaluating the plantar surface will be calculated. Inter- and intra-clinician reliability will be calculated for each of the foot-shape capture methods (Aim 1a) and differences in the overall foot shape across devices compared (Aim 1b). Aim 2: 20 individuals with diabetes and elevated plantar pressures will undergo a clinical foot exam, have foot shape captured (using the three techniques described above), and have plantar pressures recorded during barefoot and shod walking. Seven sets of insoles will be manufactured for each participant, one pair of the SoC insole and six pairs of 3D printed insoles using the various foot shape and pressure capture methods. In-shoe plantar pressure will be measured during walking while wearing the insoles. Participants will also complete a comfort and usability survey after each insole condition. Peak pressure and pressure time integral in four regions (first metatarsal head, second metatarsal head, third to fifth metatarsal head, and offloading region) of the foot will be compared. VHA currently cares for 563,000 Veterans defined by the Prevention of Amputation in Veterans Everywhere (PAVE) Program as being at high risk for ulceration and amputation. Developing custom offloading insoles that are more efficacious than the current standard of care by leveraging advances in 3D printing has the potential to reduce rates of amputation and morbidity in our Veteran population.

2029-09-30

Free to search & build · $99 one-time to unlock the application pack · No subscription

Determining Relative Abundance and Distribution of the Endangered Humpback Chub Downstream of Pearce Ferry Rapid; Lake Mead NRA

National Park Service

The objective of this Agreement is to collaboratively investigate the current distribution and abundance of the Endangered Humpback Chub in the newly formed 15-mile Colorado River reach below Pearce Ferry Rapid to the Lake Mead inflow within Lake Mead National Recreation Area (LAKE). Long-term standardized Humpback Chub monitoring of the Colorado River from Glen Canyon Dam to Lake Mead has been conducted by different entities for almost two decades. However, as the elevation of Lake Mead has decreased since 2000, approximately 15 miles of new riverine habitat below Pearce Ferry formed within LAKE, which may serve as important habitat for native fishes such as Humpback Chub. This agreement will facilitate a partnership between LAKE and G&F, AD allowing investigators from both agencies to combine resources and determine if the Humpback Chub inhabiting the downstream part of the Grand Canyon to the inflow of Lake Mead constitutes a new aggregation of Humpback Chub separate from those upstream. Humpback Chub and other endemic Colorado River species are identified as fundamental natural resources in the LAKE Foundation Document. The National Park Service Management Policies state that the Service will work to protect rare, threatened, or endangered native species. Results of this work directly address Recovery Goals and management components for multiple basin-wide efforts for the Humpback Chub, and could result in consideration of LAKE for inclusion in the lower basin recovery unit. Results of this project will also aid in future distribution predictions relative to changes in water level at Lake Mead. Park managers will be able to use this information to help prioritize projects to protect critical habitat used by Humpback Chub and other native fish, as well as help minimize future negative impacts to the species. Furthermore, results will inform us of the fish community utilizing this reach of the Colorado River, including both native and non-native species of potential management concern.

$12K – $30K

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Determining Status of Surface Water Quality in Parks of the Pacific West Region

National Park Service

United State Department of the Interior, National Park Service (NPS) Notice of Intent to Award. This is not a request for applications. This posting is to provide public notice of the NPS' intention to fund the following project activities without full and open competition: Task Agreement P16AC01362 under Cooperative Agreement P16AC00003 with Oregon State University, a partner under the Pacific Northwest Cooperative Ecosystem Studies Unit, for the project titled, "Determining Status of Surface Water Quality in Parks of the Pacific West Region."

Up to $32K

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Determining the contribution of Natural Killer Cells to the in vivo clearance of Plasmodium erythrocytic stage parasites

NIAID - National Institute of Allergy and Infectious Diseases

Abstract Malaria causes approximately 600,000 deaths annually, along with 200,000 miscarriages and 20,000 maternal deaths—primarily due to the Plasmodium blood-stage of infection. While recent advances in vaccination and monoclonal antibody therapies targeting the liver stage of infection are promising, individuals not protected by these approaches remain vulnerable to blood-stage infection and its associated morbidity and mortality. Although antibodies are known to confer protection against the blood stage, the mechanisms underlying this protection remain poorly defined. We hypothesize that natural killer (NK) cells act in concert with antibodies to kill merozoites released from infected red blood cells, thereby boosting the neutralization efficacy of the antibody. This hypothesis is supported by our lab and others with human correlations. In vitro studies have demonstrated NK cell activity against infected RBCs and merozoites, and clinical data show that enhanced NK cell antibody-dependent killing correlates with reduced parasitemia and protection from malaria. In preliminary data, we showed using re-engineered neutralizing an anti-MSP1 antibody (IgG2a) reduces parasitemia, and 31% of the reduction is Fc receptor dependent shown by IgG2a LALAPG antibody. This proposal seeks to show definitive in vivo evidence for NK cells contributing to merozoite clearance that has been obscured by differences in NK cell and Fc receptor biology between mice and humans. This proposal addresses these limitations using two complementary, innovative approaches. First, adapting a strategy from cancer immunotherapy, we will inject human NK cells and human anti-merozoite antibodies into immunodeficient mice. The in vivo function of these human NK cells will be correlated with their in vitro activity against RH5—the leading blood-stage vaccine candidate not expressed in mouse malaria. Second, we will employ a novel mouse model with an intact immune system that has been genetically engineered to overcome limitations in mouse NK cell effector function and Fc receptor engagement. Using this model with mouse anti- merozoite antibodies will enable a rigorous test of NK cell contribution to parasite clearance in vivo. Together, these experiments will clarify the role of NK cells in the antibody-mediated clearance of blood-stage Plasmodium parasites. The insights gained may inform new strategies to enhance both NK cell and antibody responses to improve malaria vaccines, immunotherapy, and prevention.

Up to $231K

2028-05-31

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Determining the effects of ambient dust exposure and extreme dust events on coccidioidomycosis in Arizona

NIAID - National Institute of Allergy and Infectious Diseases

PROJECT SUMMARY Coccidioidomycosis infections cause almost a third of community-acquired pneumonia cases in Arizona, and reported cases have doubled from 2013-2021. Coccidioidomycosis is an infection caused by inhalation of fungal spores from the soil-dwelling Coccidioides genus, and can lead to chronic lung infection, meningitis, or death. The disease is a growing public health concern in the southwestern US, particularly in Arizona, which reports around 10,000 cases per year—nearly two-thirds of US cases. The disease imposes a significant public health and economic burden, with Arizona’s 2019 cases alone estimated to cost $736 million in lifetime expenses. Yet, public health responses have been hindered by critical gaps in understanding of the environmental drivers of infection, particularly the role of dust exposure. Changing hydrometeorological factors, such as increasing aridity and more frequent dust storms, may be contributing to rising incidence, as dust and dust-generating processes (e.g., wind erosion, construction, agriculture) likely promote aerosolization and dispersion of Coccidioides spores. However, the relationship between dust exposure and coccidioidomycosis incidence remains unclear, with some studies linking short-term, extreme dust events to outbreaks and others finding no impact. This project aims to fill these knowledge gaps by leveraging a novel database of spatiotemporally refined dust concentration estimates and all reported coccidioidomycosis cases (n > 126,000) in Arizona from 2005 to 2022. Our secondary data analysis study has three aims: 1) Estimate the effects of daily ambient dust exposure on coccidioidomycosis incidence and identify populations most vulnerable to these exposures, focusing on determinants of social vulnerability such as low income, poor housing quality, and racial/ethnic minorities; 2) Assess the impact of extreme dust events on coccidioidomycosis incidence, and identify populations most vulnerable to these exposures; 3) Investigate whether hydrometeorological factors, including oscillations between wet and dry conditions that may influence spore growth and dispersal, modify the relationship between dust exposures and coccidioidomycosis incidence. Our results will help guide public health messaging and target prevention strategies in Arizona to both the general population and clinicians surrounding when and where risk of coccidioidomycosis transmission is highest; provide important evidence on the contribution of environmental change to transmission; and enable identification of populations and geographies particularly sensitive to dust exposures.

Up to $420K

2028-05-31

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Determining the effects of prenatal THC use on offspring lung development and function

NHLBI - National Heart Lung and Blood Institute

PROJECT SUMMARY Cannabis is currently the most commonly used federally illicit drug during pregnancy. It is often used to alleviate symptoms of nausea, insomnia, pain and stress during pregnancy, especially in the first trimester when the fetus is most sensitive to environmental exposures. The high prevalence of use is partly because safety data is substantially lacking. Thus, individuals continue to use cannabis when trying to conceive or during pregnancy because it is perceived as harmless. The available studies are often limited by self-reported cannabis intake and other confounding variables, including polysubstance use, but suggest that prenatal cannabis use is associated with an increased risk of low birth weight infants, preterm delivery, stillbirth and infant mortality, and have focused largely on impact to offspring neurodevelopment. Our group has recent preliminary data that shows that chronic prenatal delta-9-tetrahydrocannabinol (THC, the main psychoactive component of cannabis) exposure in pregnant rhesus macaques negatively affects offspring lung development, including decreased infant lung volumes and gas exchange, and transcriptional and epigenetic changes. As THC can readily cross the placenta and bind to cannabinoid receptors expressed in the fetal lung, there is concern that prenatal THC exposure can adversely affect offspring lung development and function. As this has not been previously studied, it is crucial to study the influence of THC on offspring respiratory health. The lack of understanding regarding the effects of prenatal THC use on offspring lung development is partly due to the paucity of relevant preclinical models for mechanistic studies with strong translation to human health. Lung development is structurally and cellularly different in primates than rodents. To address this critical knowledge gap, our proposed study will leverage our translational rhesus macaque model of chronic prenatal edible THC consumption. Edibles are the second most common mode of cannabis delivery amongst pregnant individuals and allow rigor and reproducibility in dosing. The objective of our study is to determine the impact of in utero THC exposure on offspring lung development and function. To do this we will integrate advanced imaging techniques, pulmonary function testing and lung stereology to first determine the effects on lung structure and function. Then we will analyze gene expression and alterations in DNA methylation utilizing spatial transcriptomics, whole genome bisulfite sequencing and confocal microscopy to determine underlying molecular mechanisms. The successful completion of our study will result in: 1) new insights into the effects of chronic maternal THC use in pregnancy on offspring lung development and function, 2) defining the effect of in utero THC exposure on the newborn and infant lung epigenome and transcriptome, and 3) the creation of a publicly-available non-human primate tissue bank of comprehensive biological samples and offspring tissues (control and THC-exposed). Results from our proposed work will inform future studies and guide patient counseling on maternal cannabis use.

Up to $853K

2030-03-31

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Determining the Impact of Metabolic Syndrome on the Oral Microbiome and Periodontal Health Using a Longitudinal Systems Biology Approach

NIDCR - National Institute of Dental and Craniofacial Research

Project Summary Metabolic Syndrome (MetS) affects over one-third of U.S. adults and is closely linked with oral health issues, particularly periodontitis. The bidirectional relationship between MetS and periodontitis exacerbates both conditions, but the underlying mechanisms remain unclear. Our preliminary R03 data indicate that MetS alters the oral microbiome, creating an ‘at-risk-for-harm’ environment even in the absence of clinical periodontal disease. This project aims to elucidate these mechanisms through a longitudinal systems biology approach, focusing on how restoring metabolic health impacts the functional oral ecosystem. We hypothesize that improved metabolic health will shift the oral microbiome towards a eubiotic state, reduce pathogenic strains, and alter the metabolome to a less inflammatory profile. We test our hypothesis in the following specific aims. In Specific Aim 1: We will track the oral microbiome's temporal dynamics in MetS and Metabolically Healthy Obese (MHO) cohorts undergoing lifestyle or surgical interventions, comparing them with healthy and periodontal disease cohorts. In Specific Aim 2: We will analyze changes in the oral metabolome post-metabolic intervention using advanced mass spectrometry techniques. In Specific Aim 3: We aim to identify and validate oral biomarkers and risk indicators linked to metabolic health improvements. This study will use a causal mediation framework to explore direct and indirect effects, providing crucial insights into the MetS-periodontal health relationship and aiding in the development of prognostic biomarkers and risk indicators in the future.

Up to $699K

2030-12-31

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Determining the Influence of a Predaceous Diving Beetle (Neoclypeodytes cinctellus) on the Devils Hole pupfish (Cyprinodon diabolis) and its Prey

National Park Service

United State Department of the Interior, National Park Service (NPS) Notice of Intent to Award. This is not a request for applications. This funding opportunity is to provide public notice of NPS's intention to fund the following project activities without full and open competition. Task Agreement # P15AC00255 under Cooperative Agreement P11AC8R001 with the University of Nevada, Reno, a partner under the Californian Cooperative Ecosystem Studies Unit, for project titled "Determining the Influence of a Predaceous Diving Beetle (Neoclypeodytes cinctellus) on the Devils Hole pupfish (Cyprinodon diabolis) and its Prey"

Up to $26K

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Determining the influence of neuronal mechanics on touch-evoked mechanoreceptor currents

NINDS - National Institute of Neurological Disorders and Stroke

PROJECT SUMMARY Whether due to injury, disease, or as a consequence of cancer chemotherapy, millions of Americans, both young and old, experience sensory neuropathy. This condition, characterized by numbness, tingling, and disruptions to gait, degrades the quality of life. The sheer diversity of cells that underpin the mechanical senses of touch, hearing, and proprioception pose a barrier to understanding their function in health and their dysfunction in disease. Rapid mechanosensation responsible for low-threshold touch sensation depends on the activation of specialized mechanosensitive (MS) ion channels. The proteins forming MS channels in humans and other animals have come to light over the past two decades, yet how mechanical energy causes their activation remains poorly understood. Some MS channels seem to respond to changes in membrane tension, others depend on coupling to the cytoskeleton, and still others require coupling to extracellular matrix (ECM) structures. Whereas a subset of neuropathies arise from faulty nerve transmission, many other forms involve defects in coupling MS channels to sensory stimulation or from defects in the channels themselves. This project seeks to understand how sensory stimuli is coupled to MS channel activation in vivo. Very few biological models are amenable to in vivo neuronal biophysics, including voltage-clamp of sensory neurons and to imaging MS channel complexes in living animals. The model organism C. elegans fulfills these requirements. In this research we will combine established techniques for in vivo whole-cell patch-clamp electrophysiology with cutting-edge, genetically encoded tools to visualize and measure touch-induced mechanical strain in touch receptor neurons. A large toolbox of existing mutations affecting the cytoskeleton and ECM will be used to perturb the coupling between sensory stimulation and MS channel activation, delineating the role played by each structure in this fundamental sensory process. Ample evidence indicates that the mechanics of touch are conserved even among distantly related animals, suggesting that what is learned through this research training plan has the potential to provide insight into the factors that give rise to sensory neuropathy and to other mechanosensory abnormalities.

Up to $50K

2029-11-30

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Determining the interactome and function of the neurabins across cell and tissue types.

NIGMS - National Institute of General Medical Sciences

Project Summary & Abstract: The major serine/threonine phosphatase, protein phosphatase 1 (PP1), is involved in many different biological processes throughout the body. Phosphatases like PP1 are known to “keep things in check” to limit adaptive changes from occurring under pathological conditions. Unlike their kinase brethren, serine/threonine phosphatases are more substrate promiscuous. This has historically led to the notion that they are “undruggable.” However, phosphatases like PP1 associate with myriad targeting and inhibitory proteins that permit appropriate regulation of spatial and temporal signaling. Specifically, PP1 associates with over 200 proteins that target and/or inhibit its activity at specific sets of substrates. However, knowledge of how specific proteins regulate PP1 targeting and function are poorly described. Spinophilin and neurabin, collectively termed the neurabins, are the two most abundant brain postsynaptic density (PSD)-enriched PP1 targeting proteins. While the neurabins are PSD and brain enriched, they are also located throughout the body. Moreover, we and others have found that the neurabins play roles in myriad different disease-induced adaptations, including neurological disorders, cancers, immune function, and obesity and diabetes. However, due to a lack of genetic tools, our understanding of how the neurabins impact pathological adaptive changes associated with disease is unclear, In this “Focused Technology Research and Development” R01 proposal, we will leverage our current cell type-specific spinophilin and neurabin knockout mice, as well as develop novel tools to identify and compare the spinophilin- and neurabin-specific interactomes across cell types. We have generated constructs that allow for Cre-dependent epitope tagging of spinophilin and neurabin with an ALFA epitope tag as well as an UltraID proximity ligase that we show leads to robust, specific, and selective pulldown of spinophilin and neurabin protein interaction networks in overexpression studies. To permit in vivo studies, we will generate transgenic animals to allow for tissue and cell type-specific isolation of endogenous spinophilin and neurabin interactors. These studies will validate that these approaches allow us to delineate unique and overlapping spinophilin- and neurabin- specific interacting proteins within specific cell types, setting the stage for future studies to determine how disruption of specific or overlapping interactions impacts pathological adaptations associated with a range of disorders. Successful completion of these studies will enhance our knowledge and ability to “drug” selective PP1 holoenzymes.

Up to $332K

2030-05-31

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Determining the key features of immunity associated with protection against pregnancy associated malaria

NIAID - National Institute of Allergy and Infectious Diseases

Abstract Approximately 36 million women are at risk of Plasmodium falciparum infection annually. Even asymptomatic, low-level parasitemia can lead to placental sequestration of parasites, primarily mediated by the P. falciparum VAR2CSA protein, which binds to placental tissue. This sequestration is associated with adverse pregnancy outcomes, including low birth weight (LBW), small-for-gestational age (SGA), preterm birth, and neonatal mortality. Current standard of care, intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine- pyrimethamine (SP), is increasingly compromised by widespread drug resistance. While alternatives such as dihydroartemisinin-piperaquine (DP) have shown promise in reducing parasitemia, they have not consistently improved fetal outcomes and may carry potential risks. Immunity to placental malaria is remarkably effective and often develops after a single pregnancy, mainly through antibodies targeting VAR2CSA. These antibodies inhibit parasite binding and are associated with better birth outcomes, motivating the potential for a vaccine. However, VAR2CSA is diverse, likely limiting the efficacy of current monovalent vaccines. Existing antibody assays have been limited to studying just a few VAR2CSA clades, restricting our understanding of the full breadth of naturally acquired immunity. Our preliminary work demonstrates our ability to assemble and analyze global VAR2CSA sequences from whole-genome data, and to comprehensively characterize the antibody response using phage immunoprecipitation sequencing (PhIP-seq). The objective of this K08 proposal is to leverage our VAR2CSA sequence database to design a high-resolution peptide library for PhIP-seq, enabling detailed profiling of antibody responses. We will leverage an existing longitudinal cohort of Ugandan pregnant women where blood and serum have already been collected. Specifically, we will: (1) sequence full-length VAR2CSA during pregnancy to assess how sequence variation influences infection and immunity (Aim 1); (2) evaluate how different treatments (SP vs. DP) affects the breadth of VAR2CSA-specific antibodies (Aim 2); and (3) compare primigravida and multigravida women to identify immunogenic epitopes associated with protective immunity (Aim 3). Through this research, we aim to deepen our understanding of naturally acquired immunity to VAR2CSA, inform vaccine development strategies, and ultimately contribute to reducing malaria- related maternal and neonatal morbidity. This proposal will build upon the applicant's background in malaria, bioinformatics, and genomics by providing targeted training in (1) advanced evolutionary genomics, (2) high- dimensional and longitudinal data analysis, and (3) epidemiological methodology and cohort design. An experienced mentorship team will oversee the training plan outlined. This program will thoroughly prepare the applicant for a successful independent research career as an infectious disease scientist, with a focus on host- pathogen interactions.

Up to $202K

2031-06-30

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Determining the mechanisms and therapeutic potential of novel cholinergic antipsychotics

NIMH - National Institute of Mental Health

PROJECT SUMMARY/ABSTRACT Excess dopamine in the dorsal striatum is thought to be a key driver of schizophrenia. Accordingly, there is a strong corre- lation between the potency of antipsychotic drugs and their affinity for D2 dopamine receptors (D2Rs). However, tradi- tional D2R-binding drugs are not effective for psychosis in ~30% of patients, do not address cognitive and negative symp- toms, and have many adverse effects. Recently, several new therapies have emerged that do not interact with D2Rs. These include promising drugs like xanomeline, an agonist of M1 and M4 acetylcholine receptors. One promise of this new drug class is its potential to work for more patients and address more symptoms than traditional antipsychotics. Capitalizing on this novel therapeutic mechanism requires a deeper understanding of how the drug class works. Recently, our lab used in vivo imaging to determine how two of these drugs (xanomeline and the M4 receptor selective modulator VU0467154) compare to more traditional antipsychotics. Paradoxically, we found that clinical antipsychotic efficacy was more strongly associated with the normalization of activity in striatal neurons that express D1 rather than D2 dopamine receptors (Yun et al., 2023). This was true for both traditional antipsychotics and the newer cholinergic receptor agonists—suggesting the two drug classes may have partly overlapping end effects in the brain. In parallel to these imaging studies, we developed two approaches to selectively activate (either transiently or persistently) dopamine projections to the dorsal striatum. Both approaches affect behavioral processes related to the symptoms of schizophrenia and are compatible with in vivo record- ing. Here will combine these models with in vivo imaging or microdialysis to understand the mechanism-of-action of novel cholinergic antipsychotics and use behavioral testing to explore the range of symptoms for which they may be ef- fective. Specifically, we will use dual-color in vivo imaging to simultaneously record striatal acetylcholine transmission and calcium activity in D1 or D2 receptor-expressing spiny-projection neurons (SPNs). After determining how acetylcho- line relates to D1-/D2-SPN activity and how each relates to locomotor activity, we will activate nigrostriatal dopamine neurons and observe the effects on acetylcholine and D1-/D2-SPN activity. After determining these effects, we will ask how different cholinergic receptor agonists or modulators (xanomeline, M1 agonist, M4 agonist, or an M1 positive allo- steric modulator) affect the relationship between acetylcholine and D1-/D2-SPN activity under normal and hyperdopamin- ergic conditions. The drugs we will test will allow us to directly compare receptor-specific agonism and positive allosteric modulation in isolation or in combination. Next, we will use the same drugs with our animal model of persistent nigrostri- atal dopamine neuron activation. We will use in vivo microdialysis to determine how striatal neurochemistry is altered in these animals and how different cholinergic drugs affect these changes. Finally, we will use behavior (working memory, social exploration, and auditory perception) to determine whether different cholinergic drug types normalize different be- havioral processes in this animal model. Altogether we expect these experiments will advance this new therapeutic strat- egy for psychosis by elucidating the mechanistic basis for its effects on striatal activity, neurochemistry, and behavior. In doing so, we hope to catalyze the development of better and more comprehensive treatments for psychotic disorders.

Up to $781K

2030-12-31

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Determining the mechanisms of membrane repair in the human pathogen Leishmania major

NIAID - National Institute of Allergy and Infectious Diseases

PROJECT ABSTRACT Membrane integrity is key to the survival of pathogenic protozoa, but their mechanisms of maintaining membrane integrity are poorly understood. For example, the causative agent of cutaneous leishmaniasis, Leishmania major, maintains membrane integrity using distinct lipids compared to mammalian cells. Targeting key functional differences between mammalian cells and pathogenic eukaryotes in maintaining membrane integrity represents one strategy to developing new and improved therapeutics. There is a critical need to determine the mechanisms by which Leishmania sense damage and reseal damaged membranes. Without this information, the full potential of anti-ergosterol drugs (which compromise membrane integrity) may not be realized, and new membrane- disrupting strategies will not be identified. The long-term goal is to exploit the unique membrane architecture and repair mechanisms in Leishmania to develop highly selective therapies that limit infection. The overall objective for this project is to determine the mechanisms Leishmania uses to prevent and reseal membrane damage. The central hypothesis is that Leishmania senses the influx of oxidizing agents, which triggers Endosomal Sorting Complexes Required for Transport (ESCRT)-mediated membrane resealing and shedding via a Ca2+- independent mitochondrial pathway. The rationale for the project is that Leishmania are evolutionarily distinct from mammals, yet genetically tractable organisms that have unique systems of membrane repair. Determining the differences in membrane resealing between Leishmania and mammals will provide a strong scientific framework in which existing anti-Leishmania therapies can be improved, and new therapies can be developed. To attain the objectives, these specific aims will be pursued: 1) Determine the mechanisms by which Leishmania senses membrane damage, and 2) Determine the contribution of ESCRT to membrane repair in Leishmania. In Aim 1, the working hypothesis that Leishmania sense damage via the influx of reactive oxygen species that depolarize the mitochondrion and alter lipid trafficking will be tested in lipid-deficient L. major by flow cytometry and live cell imaging after challenge with multiple toxins. In Aim 2, the working hypothesis that Leishmania reseal their membrane using Ca2+-independent, ESCRT-dependent shedding of damaged membranes will be tested by measuring repair responses to L. major expressing tagged ESCRT proteins using flow cytometry and high resolution imaging and transiently deleting ESCRT proteins. The expected outcomes are to have determined the mechanisms by which Leishmania sense membrane damage, and to have determined the contribution of Leishmanial ESCRT to membrane repair. The proposed research is innovative because it departs from the status quo by revealing the mechanism of damage-sensing in Leishmania and providing a new paradigm of membrane repair. These results are expected to have a positive impact because a better understanding of how Leishmania sense damage and repair their membrane will provide new drug targets and new paradigms of membrane repair.

Up to $609K

2029-05-30

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Determining the role of ABHD17 in Pemphigus Vulgaris

OD - NIH Office of the Director

Abstract Pemphigus is a family of rare, potentially life-threatening epidermal blistering diseases. Pemphigus vulgaris (PV) is an autoimmune disease characterized by painful blisters and erosions of the skin and mucus membranes including the oral cavity. Affected individuals produce autoantibodies targeting the adhesive domain of the desmoglein 3 (Dsg3) adhesion molecule in the desmosomal adhesion complex. PV autoantibodies primarily bind Dsg3 and disrupt cell to cell adhesive contacts between the basal and suprabasal keratinocytes in the epidermis leading to acantholysis and blister formation. Mechanisms regulating desmosome assembly, disassembly and stability are poorly understood. We recently discovered that palmitoylation of several desmosomal proteins, including Dsg3, plays an important role in desmosome assembly and stability. Palmitoylation is a reversible post-translational modification whereby the addition of a 16-carbon moiety (palmitate) is enzymatically added to cysteine residues of substrate proteins in the cytoplasm and can affect protein association with cellular membranes, subcellular localization and/or protein activity. Conversely removal of palmitate by enzymatic depalmitoylation can also influence membrane association, localization and activity. We have identified ABHD17b as a depalmitoylase acting on a desmosomal proteins to disrupt desmosomal adhesion. Our central hypothesis for this project is that inhibition of depalmitoylase enzymes acting upon desmosomal proteins will stabilize the desmosome and protect keratinocytes from disruption by PV autoantibodies. To gain insight into the role of ABHD17 proteins in this process, we propose the following aims. 1) Generate expression systems to alter the expression and activity of ABHD17 proteins in cultured cells and generate a panel of murine monoclonal antibodies specific for ABHD17 proteins. 2) Determine the role of ABHD17b in protecting keratinocytes from PV induced cell fragmentation. 3) Determine the substrate landscape for ABHD17 family depalmitoylases in keratinocytes utilizing a tandem mass tag mass spectroscopy approach. These aims build on our preliminary findings that ABHD17b acts to depalmitoylate desmosomal components and take advantage of our strengths in generating expression systems as well as producing and characterizing highly specific monoclonal antibodies specific for ABHD17 family members. Additionally, we will begin to identify the landscape of ABHD17 depalmitoylase substrates in keratinocytes and identify additional substrates that are potentially co-regulated with the desmosomal components. The depalmitoylases are attractive druggable targets that have the potential to be novel therapeutic targets in the treatment of pemphigus.

Up to $158K

2027-06-30

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Determining the Role of csoS2 in Carboxysome Assembly and Regulation

NIGMS - National Institute of General Medical Sciences

PROJECT SUMMARY/ABSTRACT Bacteria Microcompartments (BMCs) are pseudo-organelles comprised of a highly organized, semi-permeable protein shell which self-assembles around components of specific metabolic pathways. BMCs offer bacteria an advantage to survive in harsh conditions, to organize the cytosol by separating reactive components from each other, or to increase efficiency of enzymatic pathways by tuning local concentrations. Genetic models suggest that the compact organization of the BMC loci is ideally suited for lateral transfer to other bacteria, increasing the potential for greater prevalence of this feature in the future. Understanding the mechanisms of BMC assembly, organization, and stability are important to developing new approaches involving human-bacteria interactions and symbiosis. The model BMC is a key component in the CO2 concentrating mechanism (CCM) found in cyanobacteria called the carboxysome (CB). CBs sequester Rubisco with carbonic anhydrase and CO2 increasing carbon fixing efficiency. Rubisco is the most abundant enzyme on earth and the protein responsible for carbon fixation in plants, bacteria, and algae. Rubisco has low selectivity for its substrate CO2 and has a slow enzymatic rate, resulting in an inefficient metabolic pathway. By sequestering Rubisco in CBs along with additional co-factors, cyanobacteria and many chemoautotrophs have enhanced carbon fixation. We propose studying shell assembly and cargo organization in vivo and in vitro using cryogenic electron tomography (cryoET) and live cell imaging using total internal reflection fluorescence microscopy (TIRFM) to understand internal and external factors that affect BMC stability, permeability, and function. Understanding how this model BMC organizes during assembly and throughout its life cycle will be critical for developing potential bioreactors with custom cargo for pharmaceutical applications or increasing carbon fixation in photosynthetic organizations for improved crop yields and decreasing atmospheric carbon.

Up to $75K

2028-11-16

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Determining the role of localized dopamine signals in learning

NIMH - National Institute of Mental Health

Project Summary Neuromodulators like dopamine are crucial for learning, driving synaptic changes in neurons, and shaping behavior. Furthermore, dysfunction in dopamine signaling is a hallmark of almost all psychiatric disorders. Traditionally, dopamine was thought to broadcast diffuse signals across broad brain regions. However, emerging evidence points to a more targeted mechanism, where dopamine acts on specific neurons engaged in behaviorally relevant tasks. This proposal raises a critical question: How does a widely distributed neuromodulator like dopamine contribute to precise, neuron-specific learning? This project will explore how dopamine shapes learning in sparse cortical populations. We will use two-photon microscopy and genetically encoded sensors to simultaneously track dopamine release and neuronal activity in real-time as mice perform a neuroprosthetic control task. We will use this task because it allows us to directly identify the neurons that drive behavior, providing a unique opportunity to examine whether dopamine signals are more focused on task-relevant neurons. We will measure both dopamine release and the activity of specific neurons involved in behavior to determine whether dopamine shapes learning at a single neuron level or across broader networks, and what type of information can be conveyed by dopamine signals at different levels of spatial resolution. This study will help us better understand the brain mechanisms underlying learning by revealing fundamental mechanisms of how dopamine modulates neural circuits. Our results will help us understand how disruptions in these processes contribute to conditions like depression, schizophrenia, and addiction, which involve pathological learning. This research could lead to more targeted therapies focusing on dopamine-related brain circuits, ultimately offering better treatment options for people with cognitive dysfunction and maladaptive behavioral patterns.

Up to $410K

2028-03-14

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Determining the role of micronutrient deficiency in the immune response to oral rotavirus vaccine in a low-resource setting.

NIAID - National Institute of Allergy and Infectious Diseases

The World Health Organization recommends that all children be vaccinated against rotavirus, the most common cause of severe childhood diarrhea and a major cause of morbidity and mortality worldwide. Two oral rotavirus vaccines have proven to be highly efficacious against childhood diarrhea in high- and middle-income countries (85%-98%). However, virtually all trials in sub-Saharan Africa and south Asia have shown lower immune response and much lower vaccine efficacy (40%-64%), leaving many children unprotected. The ultimate goal of this research is to enhance the efficacy of oral vaccines in infants in low-resource settings by identifying the biologic basis for their underperformance in these settings. The research team hypothesizes that the predominant determinants of vaccine failure in low-resource settings are micronutrient deficiencies. Micronutrients, particularly iron, zinc, vitamin A, and vitamin D, play an important role in maintaining the integrity of gut mucosal immunity, a primary site of interaction for oral vaccines, and are critical in activating T and B-cell responses that are essential to oral vaccine response. As a result, key micronutrient deficiencies among mothers in pregnancy may result in a nutrient-deficient fetal environment that handicaps development of a functional infant immune system, while deficiency in infants may also compromise immune development in early live, leaving them unable to mount an effective oral vaccine response. This study will evaluate the associations of four key micronutrients (iron, zinc, vitamin A, and vitamin D) in 250 mother-infant pairs with infants’ failure to develop an effective immune response using plasma samples from a completed randomized, placebo-controlled vaccine efficacy trial in Niger. These four micronutrients were selected for the robust scientific evidence for their critical role in pathways key to oral vaccine efficacy (mucosal immunity and immune cell development) and the relevance to low-resource settings, where deficiency is common. In this study, we aim to test two hypotheses: Aim 1: Low maternal micronutrient concentrations are associated with impaired infant immune response to oral rotavirus vaccine (anti-rotavirus IgA seroconversion at 28 days post-Dose 3). Aim 2: Low micronutrient concentrations in infants are associated with impaired immune response to oral rotavirus vaccine. This study will guide development of new randomized clinical trials (R01) that test the causal effect of micronutrient supplementation on rotavirus vaccine performance. Implementation of such interventions at scale will boost the efficacy of oral vaccines that have historically performed poorly, increasing the impact of immunization programs worldwide.

Up to $228K

2028-03-31

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Determining the Role of Mitochondrial Hydrogen Peroxide in the Regulation of Neuronal Mitochondrial Networks

NINDS - National Institute of Neurological Disorders and Stroke

ABSTRACT The brain consumes nearly 20% of the body’s ATP despite accounting for only 2% of body weight, highlighting its disproportionate energy demand. As the cells of the brain also exhibit a limited regenerative capacity, sustained bioenergetic failure often results in a permanent loss of cognitive, sensorimotor, and autonomic function. While neurodegenerative and neurodevelopmental conditions are often multifactorial, one common theme observed across these diseases is altered metabolic homeostasis. To meet the tremendous energetic demands of intercellular communication, neurons rely on highly efficient ATP production via mitochondrial oxidative phosphorylation (OxPhos). In addition to ATP, OxPhos yields reactive oxygen species (ROS) shown to oxidize cellular lipids, proteins, and nucleic acids. While decades of research have investigated the consequences of ROS accumulation in various pathologies and aging, the role of ROS in healthy neuronal function is incompletely understood. Membrane-diffusible mitochondrial hydrogen peroxide (mtH2O2), a specific form of ROS, has become the focus of recent research due to its reported interactions with redox modifiable cysteine residues – coined redox switches. As mtH2O2 is produced in the mitochondrial matrix in a metabolic performance dependent manner, it likely exhibits direct influence on local mitochondrial dynamics to shape metabolism and maintain a healthy mitochondrial network. Our preliminary data in primary mouse cortical neurons suggests that mtH2O2 serves a regulatory role in mitochondrial fission/fusion balance. Following attenuation of mtH2O2 via depletion of superoxide dismutase 2 (SOD2), we observed a reduction in mitochondrial size within neuronal dendrites. To ascertain if this change in size is a result of impaired mitochondrial fission/fusion balance, we performed time lapse fluorescent microscopy on live primary neurons and found that while SOD2 ablation decreases the frequency of both fission and fusion events, it preferentially inhibits fusion. Thus, we hypothesize that mtH2O2 dictates local neuronal mitochondrial dynamics. We have devised two independent aims to test this hypothesis. In the first aim, we will determine the compartment- specific signaling capacity of mtH2O2 by visualizing H2O2 spatial abundance in the mitochondrial matrix and at the outer mitochondrial membrane in neuronal dendrites, somas and axons using a novel genetically encoded H2O2 reporter, HyPer7. In the second aim, we will quantify changes in mitochondrial fission and fusion following genetic manipulation of mitochondrial antioxidants – resulting in physiologically relevant changes in mtH2O2 levels – then employ targeted proteomics to identify differences in the oxidation profiles of known fission and fusion proteins. If successful, our work will characterize an essential role of mtH2O2 in mitochondrial health by its direct regulation of proteins involved in mitochondrial remodeling.

Up to $39K

2029-02-28

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Determining the Role of Notch Signaling in Atoh1 Lineage Cell Fate Decisions

NINDS - National Institute of Neurological Disorders and Stroke

Project Summary The brainstem relays information between the brain and the spinal cord, regulating vital autonomic functions. Like other tissues, the brainstem is vulnerable to malformation and disease. Yet, despite its importance, little is known about its development, making it challenging to understand brainstem pathology. Many of the neuron populations that regulate vital brainstem function arise from a homogenous progenitor pool that expresses the proneural transcription factor Atonal homolog 1 (Atoh1). Atoh1 is functionally relevant for driving migration, however, the mechanisms that regulate progenitor proliferation and prime cells for differentiation are unknown. This incomplete understanding of brainstem development has made it challenging to develop accurate in vitro models of the brainstem, thereby hindering studies aimed at elucidating disorders and disease. Recent transcriptomic mapping of embryonic mouse hindbrain development has revealed significant expression of Notch signaling genes. Notch signaling is a key regulator of cell fate decisions across neurogenesis, and it is known to regulate proneural genes such as Atoh1. Importantly, the development of in vitro models often relies on small molecule-based approaches that direct stem cell fate by mimicking native signaling environments. Yet, the specific role of Notch signaling in Atoh1 lineage development remains poorly defined, making it challenging to utilize this pathway to model development in vitro. This proposal will investigate how Notch signaling influences Atoh1 lineage progression by integrating computational transcriptomics, stem cell differentiation, and synthetic biology. The specific aims of this project are to: (1) define transcriptomic patterns of Notch signaling during brainstem development and predict regulatory function through in silico perturbation modeling; (2) engineer a novel multi-reporter stem cell line to visualize real-time Notch ligand dynamics during Atoh1-directed differentiation; and (3) modulate Notch activity in vitro to assess the impact of ligand induction on Atoh1 fate decisions. Together, this work will clarify how Notch signaling shapes Atoh1 lineage progression and establish tools to visualize and manipulate Notch signaling in vitro. These insights will provide foundational knowledge for improving in vitro brainstem models and for probing neurodevelopmental disorders linked to brainstem dysfunction.

Up to $50K

2029-04-24

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Determining the role of RBCs in sepsis heterogeneity

NHLBI - National Heart Lung and Blood Institute

Project Summary/Abstract: Sepsis, the dysregulated host response to infection, is a leading cause of death. A comprehensive understanding of the mechanisms driving the host response during sepsis is imperative, as it is often the aberrant immune response, rather than the pathogen itself, that leads to organ failure and mortality. Furthermore, the failure to translate preclinical findings into successful therapies is largely attributed to an incomplete understanding of the dysregulated immune response and the significant heterogeneity in host responses to sepsis. Central to the immune response during infection is the detection of pro-inflammatory bacterial DNA. While pathogen-derived nucleic acid sensing is essential for initiating inflammation and clearing infections, aberrant nucleic acid signaling can result in excessive inflammation, cell death, tissue damage, and ultimately, organ injury. Despite the critical role of extracellular DNA in sepsis-related organ failure, the mechanisms regulating cell-free DNA (cf-DNA) remain unclear. We recently demonstrated that red blood cells (RBCs) play a previously unrecognized role in capturing and delivering cf-DNA to immune cells and distant organs during sepsis. In a polymicrobial sepsis model, we found that impaired RBC-TLR9-mediated microbial DNA trapping reduced systemic inflammation, attenuated cytokine signaling in remote organs, and increased pathogen dissemination in severely ill mice. These findings reveal that RBC-DNA interactions are a key driver of the host response in sepsis and provide novel mechanistic insights into sepsis pathophysiology. Importantly, RBC-TLR9 plays a critical role in initiating inflammation by capturing and delivering DNA to immune cells, which is essential for controlling pathogens. Despite these advances, critical knowledge gaps remain. Our long-term objective is to define the immunomodulatory functions of RBCs in sepsis, focusing on how variability in the RBC-mediated DNA sensing and delivery pathway contributes to host heterogeneity. We hypothesize that differences in DNA sensing by RBCs—driven by variability in TLR9 surface expression, DNA capture, and uptake by phagocytes—underlie the heterogeneous immune responses observed in sepsis. This five-year proposal will investigate the role of RBCs in driving sepsis heterogeneity by addressing three fundamental questions: What are the intrinsic RBC factors that contribute to variability in DNA sensing? How does dysbiosis affect RBC-mediated pathogen DNA capture and subsequent host responses? How does RBC-delivered microbial DNA alter immune cell function? We will analyze samples from a well-phenotyped cohort of critically ill sepsis patients and conduct mechanistic studies using genetically modified mice and human erythrocytes to investigate RBC-TLR9 and microbial DNA sensing and delivery to immune cells. To study the impact of dysbiosis, we will use gnotobiotic and dysbiotic mice models to determine how microbial community alterations affect RBC-mediated DNA capture. Ultimately, this work seeks to achieve a mechanistic understanding of how RBCs and microbial DNA-induced immune dysfunction contribute to sepsis heterogeneity. By identifying novel therapeutic targets and elucidating a key mechanism underlying heterogeneous host responses, this research has the potential to address the critical need for effective treatments for sepsis-associated immune dysregulation.

Up to $719K

2030-03-31

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Determining the role of S. aureus YjbH clinical mutations in quorum sensing and infection

NIAID - National Institute of Allergy and Infectious Diseases

Project Summary/Abstract Staphylococcus aureus is a Gram-positive bacterium that causes a range of diseases from mild to severe, and it has been estimated that over 1 million deaths worldwide in 2019 can be attributed to this bacterium. Its ability to cause these infections relies on numerous virulence factors, including toxins, proteases, adhesins, immune- evasive proteins, and more that help in infection. These virulence factors are tightly controlled, enabling the bacteria to adjust their response for successful colonization and persistence. While strides are being made to understand how virulence factor regulation affects pathogenesis and antibiotic resistance, the individual contribution of each of these factors is largely unknown. One regulatory network in Gram-positive bacteria that contributes to gene expression is YjbH and Spx, which have been linked to stress responses and virulence in diverse bacterial species. However, few studies have identified how this system impacts virulence in S. aureus. In addition, clinical isolates have been found with mutations in yjbH, and how this impacts function and disease outcomes is unknown. This application uses two independent, yet complementary, Specific Aims to advance our understanding of how YjbH impacts the physiology of S. aureus and its clinical impact on pathogenesis and antibiotic resistance. Furthermore, it will clarify the role of YjbH in the cell since our preliminary data and several studies in other bacteria point to Spx-independent roles for YjbH, though this has not been carefully defined to date. Aim 1 will utilize a combination of genetic manipulation, RT-qPCR, quantitative hemolysis, and proteomics to determine how YjbH affects Agr activity. Aim 2 will be a combination of both in vitro and in vivo experiments assessing the mutations in YjbH found clinically and their relevance to pathogenesis and virulence factor regulations. This will be accomplished with genetic manipulation, quantitative hemolysis, and murine models of chronic lung infection and acute bacteremia. To accomplish these goals, a Sponsor and Co-Sponsor with complementary expertise in bacterial genetics and infection models will lead to robust training for the trainee in a collaborative research environment.

Up to $39K

2029-06-06

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Determining the role of serotonin synthesis in neuronal architecture and spine morphology

NIAMS - National Institute of Arthritis and Musculoskeletal and Skin Diseases

Project Summary/Abstract Scoliosis is a complex disorder characterized by abnormal curvature of the spine, often emerging during adolescence and resulting in long-term health and mobility challenges. Current treatments, including bracing, physical therapy, and surgery, are limited in effectiveness and do not address underlying causes. Despite its prevalence, the biological mechanisms that drive scoliosis remain poorly understood, hindering efforts to develop predictive tools or targeted therapies. Variants in serotonin synthesis pathways and decreased serotonin levels have been associated with scoliosis, yet the mechanistic links remain unclear. This project addresses that gap using a zebrafish model carrying a loss-of-function mutation in tph2, which encodes the rate-limiting enzyme for neuronal serotonin synthesis. Preliminary observations indicate that tph2-null zebrafish develop spinal curves, exhibit disrupted motor neuron architecture, and show altered locomotor behavior. The central hypothesis is that serotonin modulates motor neuron development and bilateral locomotor output, which in turn influence spine morphology through biomechanical forces during growth. Aim 1 will define the requirement and cellular source of tph2 for motor neuron development, using pharmacological rescue, cell-type-specific transgenics, and in vivo imaging. Aim 2 will determine how bilateral locomotor patterning contributes to spine morphogenesis, using high-speed kinematic analysis, selective motor neuron ablation, and manipulation of neuronal signaling. This work will establish a mechanistic link between serotonergic signaling, motor output, and spine development, offering new insight into the neurobiological basis of scoliosis. More broadly, it will illuminate how neural activity contributes to body shape, an emerging and understudied aspect of vertebrate development. The proposed fellowship includes structured training in behavioral neuroscience and biomechanics, supported by a multidisciplinary mentorship team with expertise in zebrafish genetics, motor circuitry, biophysics, musculoskeletal bioengineering, and clinical scoliosis research. This training environment will support the development of a scientist prepared to lead independent research at the interface of developmental biology, neurobiology, and human disease.

Up to $50K

2028-06-30

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Determining the role of the glucocorticoid receptor in phagocyte pro-inflammatory responses.

NIAID - National Institute of Allergy and Infectious Diseases

Project Summary/Abstract Circulating levels of cortisol, the body's stress hormone, increase during stresses like infections, which then dampens immune responses preventing excessive tissue damage. Synthetic glucocorticoids that structurally mimic cortisol are potent immunosuppressive and anti-inflammatory drugs given to patients with inflammatory conditions and to prevent transplant rejection. Patients undergoing prolonged glucocorticoid therapies are prone to opportunistic infections. The discovery of a safe glucocorticoid therapy that is immunosuppressive yet immune-active enough for the host to fight opportunistic pathogens has been challenging due to our lack of understanding of glucocorticoid biology in immunity. While the anti-inflammatory mechanism of synthetic glucocorticoid activity is well-described, increasing evidence suggests immune-enhancing properties of these drugs. However, ii is not fully known if endogenous cortisol-glucocorticoid receptor signaling regulates pro-inflammatory mechanisms. Cortisol levels are tightly regulated in the body and within cells; in addition to circulating levels, cells can autonomously regulate intracellular levels of cortisol, thereby regulating glucocorticoid receptor-mediated signaling. The overarching goal of this proposal is to identify the mechanisms that endogenous glucocorticoid signaling regulates in macrophage and neutrophil responses to pathogens. The larval zebrafish is an ideal host to tackle these questions. Optical and genetic accessibility of zebrafish larvae allows for the investigation of molecular mechanisms modulating dynamic host-pathogen interactions in a live organism. Importantly, glucocorticoid receptor mutant zebrafish are viable. Using zebrafish larvae as a model, I propose to test how glucocorticoid receptor activation affects macrophage- and neutrophil-mediated clearance of fungal-derived zymosan particles. Our preliminary data suggests that glucocorticoid receptor mutation causes aberrant zymosan clearance by macrophages and neutrophils. In line with recent findings by others, this data suggests that endogenous glucocorticoid receptor signaling promotes pro-inflammatory responses. In the first aim, I will determine the cellular mechanisms affected by glucocorticoid receptor mutation that result in defective zymosan clearance. I will use CRISPR/Cas9 to generate glucocorticoid receptor mutant larvae and use high-resolution live imaging of injected larvae. In the second aim, I will use a Gal4/UAS inducible system to conditionally overexpress an enzyme to decrease cortisol levels, specifically in macrophages or neutrophils, to test how cell-specific glucocorticoid receptor activation affects zymosan clearance. Overall, the findings from these aims will broaden our understanding of how glucocorticoid receptor signaling regulates phagocyte response to pathogens. Long-term, this information will contribute to the development of novel glucocorticoid therapies with minimal risk for opportunistic infections.

Up to $169K

2028-06-30