University Of Wisconsin-Madison

NIH Research Projects · FY 2025 · 2025-07

PROJECT SUMMARY/ABSTRACT At present, the diagnosis of Parkinson disease (PD) relies on clinical manifestation of motor signs which appear only after substantial loss of brain neurons. This diagnostic delay limits the opportunity for early intervention strategies and hampers the ability to study early PD pathophysiology. The proposed research aims to shift this paradigm by identifying and refining novel retinal biomarkers of PD that present in the prodromal stage, years before hallmark motor dysfunction. By focusing on translationally relevant, non-invasive retinal structure and function assays, and established motor assays, this study uses a longitudinal approach to define the onset and progression of PD-associated retinal disease in relation to PD-associated brain disease. The central hypothesis of this work is that quantifiable retinal pathology exists during prodromal-stage disease in a PD mouse model, which is recapitulated in the prodrome of human PD. To test this hypothesis, this project has two specific aims. In Aim 1, this work will identify features of retinal pathology in prodromal PD in a mouse model of PD using in vivo assays of retinal structure and function: adaptive optics scanning laser ophthalmoscopy (AOSLO), optical coherence tomography (OCT), electroretinography (ERG), optomotor reflex (OMR), combined with assays of motor function (pole and cylinder tests). In vivo assays will be compared with retinal and brain tissue pathology using immunohistochemistry, cell death assays, and electron microscopy. This innovative approach utilizes phenotypic definitions of retinal prodrome and motor clinical PD, rather than relying on fixed timepoints which accounts for disease progression heterogeneity in individuals, enhancing the translatability of findings to humans. In Aim 2, this work will identify in vivo retinal biomarkers of prodromal PD in humans, applying survival analysis of human subjects with OCT images from the UK Biobank who later are diagnosed with PD and comparing both inner and outer retina layer thicknesses measured via OCT with healthy matched control subjects. This fellowship includes a comprehensive training plan at the University of Wisconsin-Madison with complementary sponsor Dr. Freya Mowat (veterinary ophthalmologist clinician- scientist with expertise in animal models of retinal neurodegeneration) and cosponsor Dr. Michelle Ciucci (speech-language pathologist clinician-scientist with expertise in PD), with supportive collaborations within the Wisconsin Advanced Imaging of Visual Systems (WAIVS) lab and the Wisconsin Reading Center. The proposal and training plan is designed to enhance the physician fellow’s ophthalmology and neuroscience research skills through applied research and education in advanced imaging, medical statistics, clinical study design, and research ethics. This comprehensive training and research endeavor aims to equip the fellow with the necessary skills to emerge as an independent clinician-scientist investigator in vision research, with a project that promises significant public health impact through the potential for early, non-invasive PD detection.

NIH Research Projects · FY 2025 · 2025-07

PROJECT SUMMARY/ABSTRACT Human pegivirus (HPgV) chronically infects approximately 15% of the global human population. Although HPgV does not cause overt disease, we know very little about its biology. Currently, there are no cell culture systems for cultivating HPgV in vitro and no laboratory animals are susceptible to HPgV infection. Recently, we created the first mouse model of PgV infection by adapting a rat pegivirus to infect mice. This mouse-adapted PgV (maPgV) causes high-titer viremia in wild-type mice that persists for hundreds of days without causing overt disease, closely recapitulating key features of HPgV infection. We have also shown that maPgV utilizes a highly novel, albeit still poorly defined, mechanism of viral persistence. Thus, discovering how PgVs are able to persist in otherwise immunocompetent hosts could be a useful tool to explore mechanisms of “failed immunity.” Studies to date have indicated that most wild-type mice are able to exert a degree of anti-viral immunity against maPgV infection, but this immunity is weak and insufficient to fully eradicate the infection––a phenomenon we call “semi- control.” In contrast, ~10% of wild-type mice are capable of completely clearing maPgV infection and are immune to re-challenge––a phenomenon we call “elite control.” Preliminary data suggests that lymphocytes of the adaptive immune system are responsible for both semi- and elite-control. We will leverage the tractability of the mouse host to understand both of these phenomena with the ultimate goal of defining differences between semi- and elite-controllers that govern maPgV persistence. In Aim 1 we will determine adaptive immune functions responsible for PgV semi-control, using a panel of immune-gene-knockout mice to identify the specific lymphocyte subsets and effector functions that are responsible for maPgV semi-control and performing lymphocyte depletion studies at key time points to determine the importance of different lymphocyte populations for establishment and maintenance of semi-control. We will also introduce a highly immunogenic peptide into maPgV using reverse genetics, allowing us to track virus-specific immune responses and determine whether maPgV can “hide” this antigen from the immune system. In Aim 2 we will determine adaptive immune functions responsible for PgV elite-control, we will passively confer elite control to lymphocyte-deficient mice from elite- controllers via splenocyte transfer, then break elite control in passively-immunized mice using different lymphocyte-targeting antibodies to attribute elite control to a specific lymphocyte subset. To determine if a single lymphocyte population is sufficient to mediate elite control, we will purify lymphocyte subsets from elite controller spleens and transfer these into maPgV-infected Rag-KO mice. In Aim 3, we will generate tools to quantify anti- maPgV immune responses in semi-controllers and elite-controllers. Results from these studies will define the lymphocyte population(s) responsible for various aspects of PgV immunity (and failed immunity), with broader implications for our understanding of the immune system and the long-term consequences of HPgV infection in people.

NIH Research Projects · FY 2025 · 2025-07

PROJECT SUMMARY Neisseria gonorrhoeae is the causative agent of the sexually-transmitted infection gonorrhea and causes serious complications in women, including pelvic inflammatory disease, ectopic pregnancy, and tubal-factor infertility. Gonorrhea is more frequent in women who have bacterial vaginosis (BV). BV is the most common gynecological disorder in women of childbearing age and is associated with adverse pregnancy outcomes and enhanced transmission of sexually-transmitted diseases. We hypothesize that Gardnerella promotes N. gonorrhoeae pathogenesis in ways that affect bacterial survival via immune evasion and ability to infect new hosts via lipooligosaccharide (LOS) sialylation. Two Gardnerella virulence factors appear capable of shifting the balance between two mechanisms that impact LOS-dependent infectivity traits of gonococci. First, the cytolytic toxin vaginolysin releases epithelial cell contents in a CD59-dependent manner that promotes LOS sialyation necessary for gonococcal immune evasion through the recruitment of factor H, a negative regulator of complement killing. Second, a sialidase produced by some Gardnerella species can remove sialic acid from gonococcal LOS, a step needed to promote transmission via binding to asialyloglycoprotein receptors on endometrial cells and male urethral cells. These factors may act at different points in disease progression, since vaginolysin is predicted to be produced by certain phase variants early in infection, and sialidase is made by different phase variants at a later stage. Although Gardnerella spp. have not previously been genetically tractable, we developed methods for making targeted, selectable mutations as well as complements in the Gardnerella chromosome. We will use mutants of Gardnerella, N. gonorrhoeae, and human cell lines derived from the cervix, uterus, and the male urethra to determine the mechanisms by which Gardnerella vaginolysin and sialidase promote immune evasion and dissemination of N. gonorrhoeae.

NIH Research Projects · FY 2025 · 2025-07

ABSTRACT Productive infections by RNA viruses require faithful replication of full-length genomes. Yet many RNA viruses also produce deletion-containing viral genomes (DelVGs), aberrant replication products with large internal deletions. DelVGs interfere with the replication of wild-type virus and their presence in influenza patients is associated with better clinical outcomes. The DelVG RNA itself is hypothesized to confer this interfering activity. DelVGs antagonize replication by out-competing the full-length genome or by triggering innate immune responses. Here, we show this understanding is incomplete. We discovered a new inhibitory mechanism mediated by a previously unknown class of viral proteins. Specifically, we identified hundreds of cryptic viral proteins translated from DelVGs. These DelVG-encoded proteins (DPRs) include canonical viral proteins with large internal deletions, as well as protein truncations with novel C-termini translated from alternative reading frames. We show that DPRs are common features of influenza virus infections in culture and in humans. Preliminary results provide strong support and mechanistic data for DPR-mediated interference of wild-type virus replication. Yet, as we only recently discovered DPRs, we have limited knowledge on the scope and diversity of DPRs made during infection, the different activities they might possess, and their cumulative impact on disease. As all RNA viruses make DelVGs, many with the potential to express DPRs, this leaves a large gap in our knowledge across RNA virology. We address this with three Aims. In Aim 1, we characterize the interference activity of DPRs we have already discovered and establish their mechanism of action. Aim 2 defines the full repertoire of DPRs from primary influenza virus isolates, and tests almost all possible DPR types by screening a synthetic DPR library. Aim 3 then investigates the in vivo inhibition by DPRs and establishes their contribution to interference activities that suppresses wild-type virus replication and disease. These self-reinforcing Aims will provide a comprehensive view of DPR formation, mode of action, and impact on infection and pathology. Moreover, the detailed knowledge gained here will be critical in achieving the long-sought goal of developing DelVG-containing viruses as antiviral therapeutics.

NIH Research Projects · FY 2025 · 2025-07

PROJECT SUMMARY Holoprosencephaly (HPE) is a congenital malformation of the cerebral cortex linked to genetic disruption in Hedgehog (Hh) signaling. Hh signaling acts early in the developing forebrain (future cerebral cortex) to control transcription of key target genes by zinc-finger transcription factors GLIs. ZIC2, a transcription factor with homology to GLIs, is also linked to HPE. Our work in zebrafish showed that ZIC2 homologs zic2a and zic2b pattern the forebrain by modulating Hh signaling, but the mechanism of this regulatory relationship is poorly understood. Recently, Zic2 and Glis were shown to function as co-factors of the nucleosome remodeling and histone deacetylase complex (NuRD) in mammalian embryonic stem cells. Our preliminary evidence shows that zic2a and hdac1 interact genetically in zebrafish. These data have led us to hypothesize that Zic2 regulates the transcriptional readout of Hh signaling in the forebrain primordium through regulation of chromatin dynamics. To test this hypothesis, we will ask if Zic2 controls Hh target gene transcription by modulating histone dynamics and if it physically interacts with NuRD in the zebrafish forebrain. We have designed an innovative strategy that combines in vivo genomics and proteomics with unique transgenic zebrafish lines to answer these questions at the stage of development when the forebrain is most vulnerable to disruptions that result in HPE. Aim 1: Identify candidate Zic2 targets in the developing forebrain using CUT&RUN and RNAseq. No direct transcriptional targets of zic2 in the developing forebrain have been identified to date. We will use CUT&RUN, recently optimized for use in zebrafish, to map DNA binding sites of Zic2a, and to ask if zic2 function regulates chromatin remodeling and transcription of Hh target genes. To do this efficiently, we will adapt a CUT&RUN modification which relies on transgenic GFP-tagged Zic2a and a GFP nanobody fused to a micrococcal nuclease. Aim 2: Identify protein partners of Zic2a using in vivo proximity labeling. A role for Zic2 in regulating chromatin dynamics, suggested by recent findings in mammals, has not been tested in the context of the embryonic forebrain. We will use proximity-directed biotinylation and mass spectrometry to identify in vivo binding partners of Zic2a in the zebrafish embryo. Completion of these aims will shed light on an important, poorly understood regulatory relationship between Hh signaling and Zic2 in the developing vertebrate forebrain, removing a critical barrier toward deciphering the genetic basis of HPE.

NIH Research Projects · FY 2025 · 2025-07

Abstract Overall The goal of the Wisconsin Nathan Shock Center (WiNSC) is to catalyze research at the interface of aging, metabolism, and translation, building an environment and infrastructure that will have a significant impact locally and nationally. A solid body of literature supports the concept that the pace of aging is malleable and that loss of health in advanced years is not an inevitability. A striking commonality among the set of aging-regulating factors identified to date is their connection to metabolism. The importance of metabolic integrity extends beyond the fundamental biology of aging to the biology of disease, and the most common age-associated diseases and conditions including cancer, cardiovascular disease, diabetes, and neurodegenerative disease, all feature metabolic dysfunction. The regulation of metabolism itself is highly complex, but as a discipline, metabolism research offers the advantage of manifesting across timeframes, from acute to chronic, and across scales, from cells to tissues to whole organisms. As such, our theme will have broad appeal and will make a significant impact. To accomplish its goals, WiNSC will conduct a host of research and training activities, creating an environment that facilitates cutting-edge research in the general field of aging biology with a specific focus on the intersection of aging, metabolism, and translation. The ability of WiNSC to achieve its mission is supported by a strong institutional environment and commitment, as well as a leadership team comprised of nationally- and internationally-recognized experts in the specific areas of focus. Our strategic goals are a) to promote, coordinate, and enhance research in the basic biology of aging with a specific emphasis on aging, metabolism, and translation, which will be achieved through the coordinated action of the Administrative Core and the Research Development Core; and b) to efficiently and rapidly advance cutting-edge research at the intersection of aging, metabolism, and translation by developing novel research capabilities and leveraging existing resources, which will be accomplished through the establishment of three Research Cores, the Energetics of Longevity Core, the Discovery and Integration Core, and the Translation and Application Core. The WiNSC is designed to advance research on aging, to devise and test novel hypotheses at the intersection of aging and metabolism, and to promote and advance translation of insights from basic biology of aging studies. Our interdisciplinary team has expertise in the requisite areas of research, our focus on metabolism naturally allows for integration of cellular and tissue level research with systems level endocrinology and physiology, and our centralized infrastructure facilitates the development of emerging areas of investigation and fosters collaborative programs to advance the field, drawing upon deep local expertise and extending capabilities to the wider aging research community. Through its unique focus on metabolism and translation the WiNSC is exceptionally well positioned to advance biology of aging research and contribute significantly to the NSC Network.

NSF Awards · FY 2025 · 2025-07

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Plant and animal populations typically perform best in the particular environments in which they evolved. However, climate change is now disrupting the evolved fit between organisms and their environments, leading to population declines. Natural areas loved by people and required by native species are being drastically and rapidly changed as key species are lost. But, if there is genetic variation in the ability to survive and reproduce in a changing climate, then evolution may lift population growth enough to enable population persistence. This study will provide policy makers and conservation managers guidelines to evaluate the potential efficacy of such evolutionary rescue. The PIs will measure population growth rates and the speed of evolutionary response of Scarlet Monkeyflower to the major, multi-year drought that took place between 2011-2016 in the western United States. This project will also provide training in ecological, evolutionary, and statistical concepts and approaches for high school students, undergraduates, graduate students, and postdoctoral researchers, including those from underrepresented groups. Although adaptation by natural selection and population trends (demography) are typically studied separately by evolutionary biologists and ecologists, respectively, they are fundamentally connected by fitness. In declining populations, individual fitness is generally low and individuals do not replace themselves. However, heritable variation for critical traits can allow adaptive evolution, boost fitness, and lead to increased population growth rate. An important question is whether adaptation to changing climate will be faster than the rate of demographic decline. This study will use reciprocal transplant and resurrection studies spanning the native range of the Scarlet Monkeyflower (Mimulus cardinalis) in Oregon and California to evaluate natural selection during the 2011-2016 mega-drought. The PIs will determine if natural selection during the drought led to increased population growth rate, and whether this change was greatest in populations that started with the most heritable variation for drought-related traits and fitness. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

This I-Corps project focuses on the development of a digital tool to better diagnose chronic pain, which affects over 100 million adults in the United States and contributes to an estimated $560–$635 billion annually in lost productivity and healthcare costs. Misdiagnosis or delayed treatment can lead to serious problems, including unnecessary reliance on opioid medications. Currently, doctors mostly depend on patient self-reports and their own judgment, but that doesn’t always give the full picture of the need for pain medications. Some patients struggle to communicate their pain, and important biological signals—like heart rate and hormone levels—often go unnoticed. This solution is an artificial intelligence system that can analyze multiple sources of information, including language, behavior, and biological data, to provide more accurate insights. By improving diagnosis, the technology aims to reduce ineffective treatments and contribute to a more scientific approach to managing chronic pain. This I-Corps project utilizes experiential learning coupled with a first-hand investigation of the industry ecosystem to assess the translation potential of the technology. This solution is based on the development of a digital phenotyping platform that combines natural language processing, machine learning algorithms, and metabolic signal analysis to identify patterns in chronic pain expression. The system analyzes patient-generated language, behavioral patterns such as daily activity and self-management strategies, and physiological signals such as glucose variability to generate a multidimensional profile of the pain experience. This integrated approach advances current assessment methods by incorporating linguistic and biological dimensions often overlooked in conventional tools. The platform supports clinical decision making by providing real-time, individualized insights and has applications in electronic records integration, population-level analytics, and data-informed personalized care. This research contributes to the development of scalable, high-impact tools for improving diagnostic accuracy and system efficiency in pain management. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NIH Research Projects · FY 2025 · 2025-07

Alexander disease (AxD) is a severe neurodegenerative disorder caused by gain-of-function mutations in the gene for glial fibrillary acidic protein (GFAP) which lead to protein aggregation and a primary astrocytopathy. Symptoms vary, but failure to thrive (FTT) and frequent emesis are common and cause significant morbidity. We have developed a Gfap+/R237H rat model (R237H) in which pups fail to gain weight after weaning and become gaunt and frail as they mature. Adult R237H rats have virtually no body fat, reduced muscle mass and strength, and exhibit pica (indicative of nausea) and anorexic behavior. Growth and differentiation factor 15 (GDF15) is a member of the TGFβ superfamily that regulates energy balance and appetite and is elevated as part of the integrated stress response (ISR). GDF15 mediates reduced appetite via nausea and aversion conditioning, and the receptor for GDF15, GFRAL (GDNF family receptor alpha like), is specifically expressed by cholecystokinin neurons in the area postrema of the brainstem, a region known as the chemoreceptor trigger zone for vomiting. Our preliminary data show that astrocytes in AxD exhibit an ISR transcriptomic signature and that GDF15 is expressed by a subset of astrocytes in the brainstem of R237H rats. GDF15 is also markedly elevated in CSF in both the rat model and patients with AxD. We hypothesize that increased GDF15, promoted by the astrocyte stress response, induces nausea and anorexic behavior by directly stimulating GFRAL positive neurons in the AP/NTS, and ultimately failure to thrive in AxD. In Aim 1, to determine whether GDF15 correlates with FTT phenotypes, we will 1a) measure GDF15 in brainstem and CSF in animals treated with Gfap-targeting antisense oligonucleotides to reduce GFAP pathology and compare GDF15 expression with GFRAL neuron activation and FTT phenotypes. To determine whether GDF15 correlates with emesis and FTT phenotypes in the human disease, we will 1b) measure GDF15 in CSF and plasma from participants in an ongoing natural history study of AxD to directly compare with gastrointestinal symptoms, growth parameters, and CNS lesion locations on MRI. In Aim 2, we will 2a) determine whether the ISR drives GDF15 expression and GFRAL neuron activation by manipulating the ISR pharmacologically in R237H rats and assessing effects on GDF15, GFRAL neuron activation, and FTT phenotypes, and we will 2b,c) confirm whether the ISR is associated with GDF15 elevation on the cellular level and determine the effects on adjacent cells using single nucleus and spatial transcriptomics. Finally, in Aim 3, we will determine whether GDF15 is the major culprit in FTT by 3a) blocking the GFRAL receptor with specific antibodies and 3b) knocking down GDF15 expression in brainstem to assess paracrine effects. Current treatments for FTT in AxD (nutritional supplementation and gastrostomy tubes) are ineffective and invasive, and a better understanding of the underlying mechanisms may offer new options for prevention. In addition, determining the role of the astrocyte ISR may have broader implications for AxD and other proteinopa- thies and introduce new biomarkers for study.

NSF Awards · FY 2025 · 2025-07

This Faculty Early Career Development Program (CAREER) grant will fund research that strives to address an acceleration-bandwidth trade-off in precision motion systems to enable future integrated circuit manufacturing equipment with enhanced throughput, thereby promoting the progress of science, and advancing the national prosperity and welfare. In today’s chip manufacturing equipment where precision motion stations exist, there exists a fundamental trade-off between control bandwidth and achievable acceleration due to structural material stiffness-to-weight ratio limits. This trade-off severely limits the throughput of photolithography machines and wafer inspection systems for integrated circuit manufacturing, which directly depend on acceleration and control performance during wafer and photomask positioning stages. This research project attempts to solve this challenge by developing a new mechatronic hardware and control co-design paradigm that overcomes the acceleration-bandwidth trade-off and enables motion systems with substantially improved acceleration without sacrificing control performance, which has the potential to improve productivity in chip manufacturing and thus benefit society at large. Other applications that could benefit from this research include, but are not limited to, laser-based machining and the manufacture of high-power-density electric machines and aerospace structures. Tightly integrated with the research activities, this CAREER project’s education and outreach plans focus on enhancing the authenticity of engineering training, which will foster system-level synergistic thinking through curriculum development, open-source educational content creation, undergraduate research, and outreach efforts. This research aims to develop theoretical methods and practical tools to transcend an acceleration-bandwidth trade-off in today’s mechatronic systems, thereby tackling key technical barriers toward future chip manufacturing equipment with enhanced throughput. It strives to achieve this goal by creating a new mechatronic hardware and control co-design paradigm that enables systematic utilization of over-actuation and selected compliance. The project will work to (1) stiffen the component’s flexible dynamics through over-actuation, i.e., controlling the structure’s flexible dynamics using distributed actuation and sensing to introduce “servo-stiffness”, and (2) smartly introduce structural compliance in the actively controlled flexible modes to reduce weight and facilitate controller design. In particular, this project intends to create a structure topology exploration framework to facilitate over-actuation, conduct model-based analysis for over-actuated continuum dynamic systems, develop new robust bandwidth optimal control algorithms, and formulate robust control co-design frameworks for continuum dynamic systems. The effectiveness of the approach will be evaluated through experiments using over-actuated magnetically levitated precision stage prototypes and an in-depth life cycle analysis. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

Understanding how humans interact with the physical world is essential for teaching intelligent systems to perform complex tasks effectively. Everyday activities, such as grasping a coffee mug and taking a sip, often involve the seamless integration of visual perception and motor control, a process that current intelligent systems struggle to replicate. This project aims to bridge the gap by developing a new family of visual sensing and learning approaches to track hand motion and interpret daily interactions, all using wearable cameras. Further, this project will demonstrate a key application in occupational safety and health by adapting the technology to assess injury risks in the workplace. By advancing the sensing and analysis of human interactions, this research will deepen the understanding of human intelligent behavior, drive the development of more capable intelligent systems, and expand practical applications of such systems. The project’s outputs, including open-source algorithms and hardware platforms, will be disseminated through public competitions, online courses, and diverse outreach activities. This project will advocate a new paradigm of proprioceptive vision, where an intelligent system integrates physical awareness with visual perception to understand how its actions relate to its observations. The project’s goal will be achieved through two interconnected research thrusts. Thrust 1 will develop computer vision approaches to harness wrist-mounted, spatially distributed, miniature single-photon cameras for reconstructing hands and in-hand objects. This will create a new solution for wearable hand tracking, supporting long-term recording under various lighting conditions. Thrust 2 will create machine learning techniques to integrate egocentric videos and hand motion for understanding hand-object interactions. This will advance the foundational representation of objects and actions and enable compositional reasoning of interactions. Finally, the outcomes from both thrusts will be integrated to address a significant health challenge: assessing the injury risk of mobile workers engaged in repetitive manual picking tasks in workplaces. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

This is a project jointly funded by the National Science Foundation’s Directorate for Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award recommendation, each Agency funds the proportion of the budget that supports scientists at institutions in their respective countries. Earth’s energy budget is balanced between incoming solar radiation and outgoing thermal energy. Clouds exert a significant impact in both directions, but there has been significantly more study of the impact of clouds on incoming energy from the sun. This project will focus on the opposite route, the emission of longwave, or infrared, radiation from the Earth’s surface and how that radiation interacts with ice clouds in the high latitudes. The impact of this study will be to provide better information to the scientific community on processes that are important for understanding the warming Arctic region. The project will also enhance collaboration between US and UK scientists and provide training for early career researchers. This project addresses three primary research questions: (1) Do current representations of surface properties capture the longwave emission spectrum of snow and ice surfaces correctly? (2) Is a new light-scattering model able to reconcile ice cloud microphysics (ice crystal sizes, shapes) with energetic (radiative) impact across the longwave spectrum? (3) Can our radiative transfer models successfully match simultaneous observations of the longwave energy spectrum at the surface, within the atmosphere and at the top of the atmosphere under a variety of different atmospheric and surface conditions? The research team will address these questions through a multi-faceted plan. First, the team will use measurements from a new instrument, called the Far-INfrarEd Spectrometer for Surface Emissivity (FINESSE) that has been deployed in Norway and Canada in the past few years. The deployment in Canada was matched with airborne observations of clouds, providing both radiative and cloud properties to the research team. This data will be used to evaluate a new ice cloud optical property model, assess the impact of snow and ice emissivity models in an Earth System Model, and combine the ground and airborne data with satellite observations to achieve radiative closure from the surface to space across the infrared spectrum for the first time. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

GIScience will be held 26-29 August 2025. GIScience 2025 is a flagship conference in the field of geographic information science (GIS) and continues the highly successful conference series which started in 2000. The GIScience conference regularly attracts over 250 participants from academia, industry, and government to discuss and advance the state-of-the-art research in GIScience as well as support of the next generation of GIScience students and scientists through conference presentations, workshops, career development panels and social networking opportunities. This award will fund 25 scholars from the United States to help them attend this conference to disseminate their findings, collaborate with other scholars, and receive training in state-of-the-art GIScience techniques. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

The world has become data driven. Organizations, such as companies, domain sciences, and government agencies, increasingly have numerous datasets, scattered in many locations. When starting a data science or AI project, users often must find a specific datasets, then analyze them to extract insights. However, finding the needed datasets among a “sea of datasets” is often very difficult. So organizations increasingly use data catalogs for this purpose. A data catalog stores the names, descriptions, and other characteristics of datasets, as well the relationships among them. Users can then query the catalog to find desired datasets. As such, data catalogs have become a critical enabler for data science and AI projects. Yet the state of the art in catalog development has remained quite limited, leading to underwhelming performance that falls short of the users’ needs. In particular, not enough attention is devoted to the “pain points” of catalog users, and there is very little interaction among the research, vendor, user, and open-source tool communities. This has negatively impacted users, especially in domain sciences, with anecdotal evidence of intensive manual work to construct catalogs. This project seeks to address these limitations by first developing innovative and practical solutions for several pain points of catalog users, thereby accelerating research on these critical topics. Second, the project will combine these solutions to build SmartCat, a catalog software, and open-source SmartCat for educational and research purposes, and to serve domain science users. These technologies will facilitate the widespread deployment of data catalogs, resulting in better data science and AI for society, especially for domain sciences. Findings from the project will be incorporated into a new course, a new textbook, and a proposed computing-oriented (CS+X) major for environmental sciences. This will help improve STEM education. Finally, the project will build on the above activities to promote bridges among stakeholder communities that work on data catalogs, thereby increasing partnership between academia, industry, and others. Toward the above goals, this project considers a long-term agenda that spans the stakeholder communities (research, vendor, user, open-source tool) and applies Generative AI, especially large language models (LLMs), to solve catalog problems. The project will develop solutions to (1) enrich datasets with many types of metadata, such as table and column name expansions, textual descriptions, and tags, (2) discover relationships among the datasets, such as unionable, joinable, and lineage relationships, and (3) help users find desired datasets via browsing, keyword search, and natural language querying. These solutions will significantly advance the state of the art in data catalog, data discovery, and data integration, as well as the application of Generative AI to data management. The project introduces new core problems that are serious “pain points” for catalog users, but have received little attention from the research community. It considers problems that have been extensively studied, but points out the limitations of existing approaches, and proposes novel solutions. Like many current works, it also considers LLMs, but does so in the context of a real-world data management problem, namely data catalog. This uncovers serious novel challenges that studying LLMs in isolation does not. Finally, the project studies how to combine LLMs with a variety of other techniques, such as human-centric data management, traditional machine learning (ML), and big data scaling techniques, to build practical data catalog solutions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

Fractures in underground rock formations significantly influence how water, solutes, and colloids move through the subsurface. These processes are crucial to addressing real-world challenges such as ensuring drinking water quality; providing sufficient water quantity for consumption, agriculture, and industrial purposes; and managing geothermal energy, carbon dioxide, hydrogen, and natural gas storage resources. However, the complexity of fractured rock systems makes them difficult to study and represent with mathematical models. This project will use multi-scale advanced imaging and geophysical monitoring technology to "see through" rocks and quantify how fluids and colloids move through fractures. These rich datasets will enable the development of simpler, more efficient models for predicting flow and transport in fractured rocks and thus enable scientists and engineers to better manage subsurface water resources. In addition to advancing science, this project prioritizes education and outreach. A major objective of the educational plan is improving STEM education in rural Wisconsin. Through a partnership with a nature-based learning center, hydrology modules will be developed for middle school summer camps, high school field trips, and community visitor events. Collectively, the education plan objectives of this project are anticipated to improve hydrogeology education across different educational levels, enhance participation of individuals from rural communities in central Wisconsin, and broaden student recruitment and participation in geoscience and hydroscience. The research objectives of this project are focused on how fracture-matrix exchange and fluid flow channelization impact solute and colloid transport in fractured rocks. The specific objectives are to 1) experimentally quantify flow channelization and fracture-matrix exchange in fractured rock cores using positron emission tomography, 2) measure and model differences between solute and colloidal channelization behavior and the role of colloidal attachment on flow channelization in fracture cores, and 3) upscale reduced physics flow and transport models using observational data from experimentally generated mesoscale fracture networks. Multiscale laboratory data will provide spatially and temporally-resolved observations of channelization and fracture-matrix transport in different rock lithologies. This unique observational data will be used to develop and parameterize reduced physics graph-based models that capture the minimum physics necessary to describe essential characteristics of flow and transport in fractured rocks. This contribution will be significant because field application of these computationally efficient models requires an understanding of how model properties vary in different lithologies and fracture geometries across spatial scales while accounting for subsurface uncertainty. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

This I-Corps project focuses on the development of an accurate and precise quality control testing device for evaluating and approving powdered materials, referred to as qualifying feedstock powders, used in powder-based additive manufacturing (AM). The quality of the AM printed components depends on the quality of the powders that feed into the AM machine. If not closely monitored and controlled these powders can cause manufacturing defects. Qualifying feedstock powders is critical to ensuring repeatability, part quality, and performance, especially in industries like aerospace, medical device, and automotive, where safety and performance standards are strict. This solution provides a powder spreadability testing device that addresses this challenge. The adoption of this device has the potential to increase product quality and consistency, reduce machine downtime, reduce powder waste, and shorten the development cycle for powder bed-based additive manufacturing. This I-Corps project utilizes experiential learning coupled with a first-hand investigation of the industry ecosystem to assess the translation potential of the technology. This solution is based on the development of a testing device that can accurately test and quantify the spreadability of feedstock powders for powder bed-based additive manufacturing processes. The powder testing methods currently used in the additive manufacturing industry test the flow behavior of powders as bulk assemblies, meaning that the powder is being studied as a group, not particle-by-particle. Furthermore, the conventional powder testing methods cannot capture the powder behavior under actual additive manufacturing conditions, which requires assessing the spreading behavior of powders as a thin layer (normally 30-100 micrometers) between a substrate and a recoater, the mechanical device that spreads a thin, even layer of powder across the build platform. The commercialization of this technology could increase the competitiveness of the U.S. additive manufacturing industry and promote the adoption of additive manufacturing processes in the aerospace, healthcare, and energy industries for mission critical components. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NIH Research Projects · FY 2025 · 2025-07

PROJECT SUMMARY / ABSTRACT There are more than 38 million people still living with HIV-1 infection worldwide, and more than 1.1 million in the United States alone. HIV-1 acute infection and latency reversal are both dependent on the expression of full- length unspliced viral RNAs (US-vRNAs) that serve dual roles in the cytoplasm as either (1) viral mRNAs encoding Gag and Gag-Pol proteins that drive virus particle assembly or (2) viral RNA genome substrates bound by Gag/Gag-Pol for packaging into virions. This project combines live cell and super-resolution imaging, biochemical assays, and other research tools to address key foundational issues in HIV-1 US-vRNA subcellular trafficking with the goal of exposing new virus and cell biology of potential relevance to novel antiviral strategies. Aim 1 is to determine why HIV-1 evolved to exploit a highly unconventional RNA export machinery regulated by Exportin-1 (XPO1, also known as CRM1) for US-vRNA nucleocytoplasmic transport, and how cooperativity- based RNA-protein interactions regulated by the viral Rev protein serve to activate this pathway. Our preliminary data and prior studies support a model wherein Rev multimerization on the US-vRNA’s Rev response element (RRE) forms a multi-NES complex needed to recruit at least two XPO1 proteins for activation of US-vRNA nuclear export. Moreover, live cell imaging has indicated that US-vRNA transcripts first build up in the nucleus prior to exhibiting “burst-like” nuclear export kinetics when virion production is initiated. We will test the hypothesis that burst export is explained HIV-1 US-vRNAs, Rev, and XPO1 interact in a stepwise manner to ultimately link viral transcription to nuclear pores, thereby upregulating late-stage delivery of US-vRNAs to the cytoplasm. To this end, we will carefully dissect Rev and the US-vRNA’s transitional stages over space and time in single cells using a combination of live cell imaging and an innovative “cell expansion” superresolution light microscopy technique. Our goal is to precisely define the subnuclear sites of Rev-US-vRNA and Rev-XPO1 interactions and understand the effects of prescribed perturbations to these essential processes, including a profound cell-specific block to HIV-1 US-vRNA nuclear export observed in mice and other rodents. For Aim 2, we will extend these studies to the cytoplasm, again using live cell and super-resolution imaging in combination with RNA capture proteomics to test the hypotheses that Rev-dependent nuclear export licenses viral RNAs for (1) enhanced stability in the cytoplasm and (2) preferred delivery to sites of genome packaging into virions. These experiments will take advantage of newly described mutant forms of HIV-1 that allow us to, for the first time, study US-vRNAs that are specifically programmed for either translation or packaging fates. We will also exploit these comparative conditions to identify new host proteins/pathways specifically associated with US-vRNA translation vs. packaging. Collectively, these studies will provide new mechanistic insights into the viral and cellular machines that drive HIV-1 genome trafficking and advance the development of new technologies for studying HIV-host interactions.

NSF Awards · FY 2025 · 2025-07

Adding large polymer molecules to a liquid can lead to a substantial reduction of energy losses in the turbulent flow regime, which is characteristic of many flows in nature and technology. A similar effect arises in solutions containing certain surfactant (detergent-like) molecules. These additives give a liquid an elastic character that is absent in simple liquids like water. The phenomenon is used to improve energy efficiency in flow processes ranging from oil pipelines to geothermal district heating operations, but the mechanisms underlying it remain poorly understood. This project will reveal universal features of the flow structures underlying this drag reduction effect by using computational fluid dynamics simulations in multiple geometries. The outcome will advance the understanding of turbulence in viscoelastic fluids encompassing both polymer and surfactant solutions, enabling the design of fluids and flow processes that decrease energy consumption. The research team will partner with the UW-Madison Institute for Chemical Education to provide educational opportunities. Undergraduate engineering students will develop project-based lessons in fluid mechanics and present them at 4H, Wisconsin Science Festival, Engineering Expo (UW-Madison College of Engineering outreach event), and local science nights at schools. Recent studies have revealed two regimes of near-wall turbulence in viscoelastic polymer solutions. In the first, turbulence is sustained by quasi-streamwise vortices. As viscoelasticity becomes more important, the second regime emerges, where these vortices are suppressed and a new type of flow, denoted elasto-inertial turbulence, emerges. This project tests the hypothesis that elasto-inertial turbulence has universal structural and mechanistic features across parameter space and flow geometry. Direct simulations of turbulent dynamics in polymer solutions will be analyzed using an extension of Spectral Proper Orthogonal Decomposition appropriate to complex fluids. This work will be complemented by linear and weak-nonlinear analyses to reveal the mechanisms behind the nonlinear self-sustaining nature of elasto-inertial turbulence. Direct simulations and analysis will also be performed with a new model of viscoelastic surfactant solutions developed by the principal investigator’s group to understand whether universality in elasto-inertial turbulence extends to other complex fluids. This work will set the stage for studies of heat and mass transfer and whether elast-oinertial turbulence can be suppressed, leading to even further reductions in turbulent drag. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

The Seventh International Conference on Quantitative Ethnography (ICQE25), to be held in the fall of 2025, will build the capacity of NSF-supported communities to benefit from the highly promising research methodology of quantitative ethnography. Quantitative ethnography addresses the challenge of conducting rich qualitative analyses by using statistical techniques to warrant grounded, quantitative claims about thick qualitative descriptions. Quantitative ethnography can be applied to many contexts including STEM education research, learning analytics, learning sciences, and the social sciences more broadly. The funding will support doctoral students and early career scholars' participation in the conference in order to build their skills in quantitative ethnography and grow the community of scholars. Doctoral students and early career scholars will attend a workshop at the beginning and end of the conference geared specifically towards building their technical skills as well as connecting them with mid-career and senior scholars well-versed in quantitative ethnography. They will also have the opportunity to learn from and engage with a slate of multi-disciplinary symposium speakers who use quantitative ethnography, who will also be supported through this funding. The conference activities will provide opportunities for skill development and community building within the quantitative ethnography community of researchers. This project is supported by NSF's EDU Building Capacity in STEM Education Research (BCSER) program, which is designed to build investigators' capacity to carry out high-quality STEM education research. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

This I-Corps project focuses on the development of a non-invasive imaging solution designed to improve how therapeutic cells are evaluated in biomedical research. Cell therapies are becoming a critical tool in the treatment of diseases such as cancer, but current evaluation methods are slow, costly, rely on invasive tissue sampling, and provide only static snapshots of dynamic biological processes. This solution addresses these limitations by enabling researchers to visualize and quantify the behavior of therapeutic cells inside the body over time. This advancement holds promise for reducing preclinical development timelines, lowering research costs, and improving the quality of early decision-making in therapy development. By making cell therapy research more efficient and dynamic, the project supports the national interest by promoting scientific progress, advancing public health, and strengthening innovation in the life sciences sector. This I-Corps project utilizes experiential learning coupled with a first-hand investigation of the industry ecosystem to assess the translation potential of the technology. This solution is based on the development of a radiolabeling platform that enables direct, quantitative imaging of living therapeutic cells using positron-based medical imaging. The platform involves chemical oxidation of cell surface sugar residues, site-specific conjugation of a modified metal-binding agent, and stable incorporation of a positron-emitting isotope. The resulting labeled cells maintain viability and function, allowing for high-resolution, whole-body tracking. Unlike conventional methods that require invasive procedures and large cohorts, this technology allows for longitudinal assessment in the same subject, reducing variability and increasing data quality. By enabling early, real-time insights into the distribution and persistence of therapeutic cells, the platform supports more informed preclinical evaluations and faster translation of cell-based therapies from laboratory research to clinical application. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

Rapid electrification of numerous applications such as transportation, grid and high-power motor drives is going to play a critical role in achieving the goal of a sustainable society. This places an urgent need for efficient utilization of available electric power, considering 80% of the total generated electric power is expected to flow through power electronics by 2030. The development of innovative and extremely efficient power electronics is critical for incumbent ubiquitous applications as well as new applications such as grid-connected solar inverters, electric cars etc. Furthermore, this will aid in enhancing economic and technical competitiveness of the U.S. At the heart of every power conversion process is a transistor which governs the form-factor, efficiency, and overall system performance. Therefore, the power semiconductor transistor is a key enabler of extremely energy-efficient power electronics. The emerging electrification needs 1.7 to 10 kV power semiconductor transistors which cannot be served by incumbent solutions. The key objective of this NSF proposal is to demonstrate Ultra-wide band gap transistors up to 10 kV breakdown voltage with ~10x lower on-state resistance compared to the incumbent (SiC) technology and perform a detailed investigation to understand the physical mechanisms which governs transistor operation and reliability. To achieve these objectives, multiple innovative approaches will be utilized, resulting in numerous first-of-its-kind studies and demonstrations. This research effort will be complemented with efforts for education and workforce development activities as well as broadening participation amongst K-12, pre-college, and college students. The key objective of this NSF CAREER proposal is to leverage the ultra-wide bandgap material i.e. high composition AlGaN and demonstrate state-of-the-art 10 kV transistors. This project will focus on the following research goals.: 1) First demonstration of Al>0.6Ga<0.4N channel FETs with breakdown voltages >3 kV and up to 10 kV; 2) Achieving near-theoretical electric-field (~10 MV/cm) handling capability in these FETs. 3) Significant reduction of on-resistance by ~10x compared to incumbent SiC technology for 10 kV rated power transistor; 4) First detailed investigation of the electron trapping behavior under stress conditions using photo C-V, time dependent breakdown and hot carrier injection studies in high voltage Al>0.6Ga<0.4N channel transistors; 5) Identification of critical thermal boundary resistances in the Al>0.6Ga<0.4N channel transistor’s epitaxial structure and strategies to minimize them. Additionally, a competitive STEM workforce will be trained through curated wide band gap semiconductor short courses for industry professionals and also by working with industry and local technical colleges to offer a hands-on internship program to meet rising technician needs. Furthermore, efforts will be made to enhance education by training a high school teacher in wide band gap semiconductors and developing a hands-on activity to be integrated in advanced physics curriculum at high school level. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

Non-interactive Zero-Knowledge (NIZK) proofs provide a powerful means of verifying properties of private data without revealing any of that data: anyone can check the resulting proofs at any time in the future. Rapid advancements in recent years have made NIZK technology a promising tool for verifiable computation, privacy enhancing technology, and verifiable machine learning; however, these systems are built and optimized in an ad-hoc manner, with very little exploration of the fundamental programming abstractions that NIZK proofs enable. The project’s novelties are programming abstractions that simplify the development and maintenance of projects using NIZKs, techniques for reasoning about the security of large programs using NIZKs and the performance implications of using NIZK technologies, and languages for describing the security policies of realistic applications. The project's impacts are increased productivity of developers and increased software quality of software artifacts that leverage NIZK technologies. The project will also train graduate students. This project will develop techniques for (1) combining code that efficiently generates a NIZK proof and code that verifies it, tackling its inherent duality head on; (2) expressing the security guarantees provided by NIZKs in the language of information-flow control (IFC), addressing both how such guarantees compose in larger systems, as well as exploring the performance overhead of the new abstractions using static amortized resource analysis; and (3) integrating advances in realistic applications, verifying end-to-end security properties of systems that rely on NIZK proofs, such as anonymous credential systems and private payment systems with anti-money laundering protections. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

This project will conduct fundamental research on mathematical models that describe complex interactions, growth, and motion in an irregular environment with stochastic unpredictability. The goal is to discover general mathematical laws that govern such systems, which appear quite different at small scales and at large scales. It is important to understand how different kinds of small-scale evolution lead to different large-scale systemwide behaviors. Real-world phenomena modeled by these mathematical systems include the motion of vehicles in traffic, data packets in communication networks, fluid particles in a tube, fluid spreading in a porous medium, epidemics advancing in a population, and the fluctuations of a polymer chain in a fluid. Laboratory experiments have demonstrated that these mathematical models capture essential features of physical reality. Understanding complex interactions has profound implications for science and engineering and thereby for society. This project also produces educational materials on the mathematics of random phenomena and provides training for young researchers. This project investigates mathematical models of growth and motion in random media, such as first-passage percolation, the corner growth model, and directed polymer models. The outcomes of this project are mathematically rigorous descriptions of the behavior of mathematical models of growth and robust tools for their analysis. A central question pursued in this project is to understand which mathematical growth models have product-form invariant distributions. Other goals of this project include descriptions of the environment around an optimizing path in terms of functions that can be computed from the environment, the joint probability distributions of geodesic trees and competition interfaces, and the regularity properties of large scale limit shapes. A long-term goal is the extension of the results for two-dimensional growth models to higher dimensions where the behavior of these models is much more complicated. The methods employed in this work are those of rigorous mathematical research, aided by experimental computer simulation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-07

This project investigates how the rapid evolution of an agricultural pest makes it more difficult to control using natural means. People think of evolution occurring in geological time, with eras like the Dinosaur Age populated with different organisms from what we have on Earth today. Most studies of evolution, however, look at changes that occur in days or years in organisms that are all around us today. Scientists are realizing that rapid evolution is common and affects all organisms. For example, many agricultural pests in the USA are controlled by predators that attack and kill them, making insecticides unnecessary. Pea aphids represent a great example of this, because they are kept in check by predators. However, pea aphids can evolve resistance to predators. This rapid evolution raises the risk of greater crop damage. Despite their ability to evolve resistance, all the pea aphids do not become resistance to predators. There are also some that remain susceptible, creating a balance between resistance and susceptibility. This project aims to uncover how this balance is maintained, and how agricultural management practices can reduce the risks of agricultural pests becoming resistant. Understanding this balance will help to develop strategies to make US agriculture more resilient and increase the security and sustainability of our bioeconomy. The project will also provide hands-on research experiences to students with no prior experience. Public outreach events will engage farmers to share the results of the research broadly. The research investigates the ecological-evolutionary dynamics of pea aphids and their parasitoid wasp, Aphidius ervi. Aphidius ervi was deliberately introduced to North America as a biocontrol agent of pea aphids, particularly to control pea aphids as pests of alfalfa crops. Pea aphids are a leading model for investigating the evolutionary and ecological consequences of symbiosis because all populations harbor heritable symbionts that provide well-documented benefits. The most common and best studied facultative symbiont, Hamiltonella defensa, confers resistance against A. ervi. Although evolutionary theory predicts that resistance traits will often be bimodal (either susceptible or highly resistant), pea aphids exhibit a full spectrum of resistance through different symbiont variants. Although the prevalences of different symbiont variants fluctuate (reflecting the intensity of parasitism and selection), the collective of symbionts across the spectrum of resistance appears to be stable. Furthermore, the ecological interactions between pea aphids and A. ervi are stable, in the sense that A. ervi is always present but abundances never get high enough to extirpate pea aphids. This ecological stability of A. ervi-pea aphid interactions may itself be the product of the evolutionary stability of the symbionts that confer pea aphid resistance to A. ervi. The research will use field experiments, lab experiments and mathematical modeling to examine both the evolutionary and ecological stability of A. ervi-pea aphid interactions, and whether this stability is generated by the interconnections between evolutionary and ecological dynamics. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NIH Research Projects · FY 2026 · 2025-06

ABSTRACT The development of the nervous system requires the proper differentiation, migration, morphogenesis and maturation of neurons. The morphological differentiation of individual neurons and the assembly of the trillions of neuronal connections that compose the human nervous system occurs through guided extension of axons and dendrites. While many studies have investigated the molecular mechanisms that regulate axon guidance over two-dimensional substrata in vitro or along axonal tracks in vivo, little is known about cues that control axon guidance across three-dimensional tissues and through basement membranes. These are fundamental questions as numerous distinct types of axons must penetrate basement membranes to enter diverse tissue targets. Our preliminary and recently published data suggest that along with planar filopodia and lamellipodia, growth cones generate orthogonal protrusions in vitro and in vivo that resemble podosomes or invadopodia. Podosomes and invadopodia, collectively referred to as invadosomes, are distinct actin-based cellular protrusions associated with extracellular matrix (ECM) degradation and tissue invasion. We hypothesize that distinct ligands in the environment of growth cones promote invadosome formation, maturation and function. Further, we hypothesize that mature invadosomes use microtubules to target matrix metalloproteases (MMPs) to their cell surface and support local MMP secretion. Several compelling pieces of preliminary data suggest that EGF ligands (EGF and Neuregulins), promote invadosome formation and maturation by motor and Rohon Beard neuron growth cones, leading to ECM remodeling by MMPs and axon exiting the spinal cord. The three aims of this proposal will use a series of molecular gain of function and loss of function manipulations, together with live and fixed cell fluorescence imaging in vitro and in vivo, to assess the receptors/ligands, as well as the signals, that control invadosome formation and their roles in driving peripheral axon exiting the spinal cord.