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Enteric neuro-immune interactions in host defense
No full textThe enteric nervous system (ENS) can profoundly influence gut immune cell function and the inflammatory response. However, despite the numerous examples of ENS-derived neuropeptides modulating immune cell function, our understanding of how enteric neurons directly sense inflammatory cues produced during infection is considerably lacking. Therefore, a thorough characterization of the mediators capable of being sensed by enteric neurons is critical to understanding enteric neuron function and dysfunction in gastrointestinal disease.
To survey the expression of immune-related receptors on enteric neurons, we integrated three publicly available single-cell RNA-sequencing (scRNA-seq) datasets profiling enteric neurons of the small intestine, finding that the single cluster of primary enteric sensory neurons (PSNs) co-expressing Nmu and Calcb, encoding the immunomodulatory neuropeptides NMU and CGRPβ, was highly enriched in genes encoding the receptor for the type 2 cytokines IL-4 and IL-13 and its essential signaling components. Using in vitro enteric neuro-glial cultures and in vivo mouse models of PSN-specific Il13ra1 deletion, we discovered that direct PSN recognition of IL-4 and IL-13 is sufficient to upregulate NMU and CGRPβ expression. Furthermore, deletion of Il13ra1 in PSNs impaired host defense to the gastrointestinal helminth H. polygyrus and significantly diminished duodenal PSN neuropeptide expression, PSN innervation to the villi, and PSN abundance in the myenteric plexus.
Moreover, PSN Il13ra1 deletion blunted anti-helminth type 2 immune responses in a site-specific manner, reducing Il5 expression in muscularis ILC2s, eosinophil recruitment to the muscularis, and muscularis macrophage (MMφ) expression of genes involved in tissue repair and anti-helminthic immunity, like Arg1/arginase-1. Importantly, co-administration of NMU23 and CGRPβ rescued helminth clearance deficits and restored type 2 immunity and MMφ arginase-1 expression.
In summary, our work illustrates the importance of direct cytokine sensing by PSNs during gastrointestinal helminth infection and delineates a mechanism of site-specific anti-helminth immunity in the muscularis externa. We further define how the highly correlated NMU and CGRPβ expression in PSNs promotes appropriate muscularis-specific anti-helminth immunity while buffering inflammatory tissue-damage, highlighting the essential bi-directional neuro-immune crosstalk regulating intestinal type 2 inflammation.Immunolog
Physiological, morphological, synaptic, and behavioral analyses of genetically defined myelinated nociceptors
No full textPain can be both devastating to individuals and costly to the healthcare system. Yet, our understanding of pain biology and the primary sensory neurons that drive pain, nociceptors, is incomplete. We recently generated two mouse lines, Smr2Cre and Bmpr1bCre, that label A fiber high-threshold mechanoreceptors (A-HTMRs) in hairy skin and hypothesized that the labeled neurons are myelinated nociceptors. Here, we report on physiological, morphological, functional, and synaptic analyses of genetically defined myelinated nociceptors in non-hairy, or glabrous, skin to understand their unique contribution to the experience of pain. The A-HTMRs are found to be among the few somatosensory neuron types capable of evoking place aversion and nocifensive behaviors in response to minimal stimulation. Consistent with the original definition of a
nociceptor, these neurons are activated only by very intense stimuli. Both A-HTMR populations are necessary for protective responses to sharp mechanical stimuli. These protective neurons densely innervate the skin and a variety of other organs, including joints and cranial meninges. Centrally, A-HTMRs form unique projections that span multiple spinal segments and terminate in the superficial and deep laminae of the spinal cord dorsal horn, where they form monosynaptic connections on projection neurons of the anterolateral tract. A-HTMRs also engage a local spinal reflex circuit that enables quick paw withdrawal in response to damaging stimuli. Thus, A-HTMRs are bona fide myelinated nociceptors with unique physiological, morphological, and synaptic properties. Future work on characterizing and manipulating these neurons may yield important insights for the development of analgesics.Neuroscienc
Characterization of endogenous cereblon substrates with new chemical biology methods
No full textC-Terminal cyclic imides are posttranslational modifications on proteins that are recognized and removed by the E3 ligase substrate adapter cereblon (CRBN). Despite the observation of these modifications across the proteome by mass spectrometry-based proteomics, an orthogonal and generalizable method to visualize the C-terminal cyclic imide would enhance detection, sensitivity, and throughput of endogenous CRBN substrate characterization. I therefore developed an antibody-like reagent, termed “cerebody,” for visualizing and enriching CRBN substrates. I describe my protein engineering campaign to identify cerebody and showcase cerebody’s utility in identifying CRBN substrates by Western blot and enrichment from whole cell and tissue lysates. Furthermore, CRBN substrates identified by cerebody enrichment are mapped, validated, and further characterized for dependence on the C-terminal cyclic imide modification. These methods will accelerate the characterization of endogenous CRBN substrates and their regulation.
In Chapter 1, I introduce the E3 ubiquitin ligase substrate adaptor CRBN and provide an overview of its clinical use, structure, substrates it recognizes, and recognition motifs. I then discuss methods to recognize CRBN substrates through the C-terminal cyclic imide modification, and criteria for improved methods for detection of CRBN substrates through this modification. In Chapter 2, I discuss the directed evolution of CRBN’s thalidomide binding domain through random mutagenesis phage display in pursuit of a tool protein for detection of CRBN substrates. In Chapter 3, I move from the thalidomide binding domain scaffold to CRBNmidi and describe the development of the tool protein called cerebody. I then detail its use for detection and enrichment of endogenous CRBN substrates. In Chapter 4, I describe the validation of UROD as a PCMT1-dependent CRBN substrate, a discovery which was enabled and accelerated by cerebody enrichment. In Chapter 5, I discuss the utility of cerebody beyond endogenous substrates, including its use for identifying CRBN neosubstrates and its potential alterations to also provide structural insight into the interface between CRBN and its substrates and neosubstrates. I also provide detailed protocols for the implementation of cerebody methods. I conclude by discussing the broad applicability for cerebody and derived methods to illuminate CRBN’s biology, and what happens when these pathways are altered.Chemistry and Chemical Biolog
Patterning the Vertebrate Retina - Molecular Mechanisms Underlying the Development of Retinal High Acuity Area
No full textThe vertebrate retina is not a uniform sheet of neurons but is patterned into distinct domains, with the central region being uniquely specialized. The ability to see in fine detail relies on this small region specialized for high-acuity vision. Known as the high-acuity area (HAA), this domain is defined by several striking features: a high density of retinal ganglion cells, which serve as the output neurons of the retina; an enrichment of cone photoreceptors, which mediate daylight and color vision; and a complete absence of rod photoreceptors, which instead support dim-light vision. This architecture allows signals from a small number of cones to be transmitted directly to individual ganglion cells, reducing convergence and enabling exceptional spatial resolution. Together, these specializations endow the HAA with its critical role in enabling sharp central vision.
The human HAA, known as the fovea, is distinguished by its characteristic pit-shaped morphology and by being a rod-free, cone-dense region that supports high-resolution tasks such as reading and facial recognition. However, very little is known about the molecular and developmental mechanisms that give rise to this specialized region. This gap in knowledge is compounded by the fact that commonly used mammalian models, such as mouse and rat, do not possess an HAA at all, thus, limiting their use for developmental and disease studies. Interestingly, certain birds possess an HAA that shares many structural and functional features of the primate fovea. Unlike in humans, the chick retina offers ready access to embryonic tissue and is highly amenable to experimental perturbation, making it a powerful system for probing the developmental logic of high-acuity specialization. In this dissertation, we use the chick retina to investigate how the HAA is generated, to define the molecular patterning events that localize and specify this specialized territory, and to understand how these principles extend across species.
First, we characterized the morphological development and cellular composition of the chick HAA, defining when specialized photoreceptor and ganglion cell patterns emerge and how they differ from peripheral retina. Using single molecule fluorescent in situ hybridization (smFISH) in combination with classical histological methods, we identified Fgf8 as a robust molecular marker of the HAA that persists throughout embryonic development. We showed that the ganglion cell layer (GCL) was consistently thickest at the HAA beginning during the period of neurogenesis. This pattern indicates that elevated production of retinal ganglion cells, rather than selective survival or death, accounts for their enrichment in this region. In contrast, rods photoreceptors were entirely absent from the HAA, and analysis of apoptotic markers showed no evidence of rod elimination, suggesting instead that rods fail to be generated there. Together, these findings show that distinct developmental processes (differential neurogenesis, delayed cone accumulation, and restricted rod genesis) combine to build the specialized architecture of the HAA.
We next asked how positional information is encoded to localize the HAA within the naso-central retina. To do so, we developed an integrated framework combining multiplexed gene expression imaging with single-cell transcriptomics, enabling quantitative 2D reconstruction of molecular expression domains. This approach revealed sharp boundaries in signaling pathways, identified novel HAA-enriched candidates, and provided a reproducible spatial atlas of the developing chick retina. By anchoring spatial reconstructions to experimental landmarks such as the Fgf8 expression domain, we demonstrated how expression domains of retinoic acid-Fgf8 signaling pathway components correlate with classical dorso-ventral and naso-temporal patterning axes to establish a unique retinal territory.
Finally, we extended this framework across vertebrate species. By comparing chick, human, and mouse single-cell datasets, we identified conserved axis-based programs as well as species-specific spatial patterns. Both chick and human retinas contained distinct domains consistent with an HAA, whereas mouse retinas resolved primarily into broad DV and NT axes, consistent with their lack of an HAA. Additional comparisons across birds, and reptiles highlighted both conserved and divergent molecular strategies underlying the evolution of high-acuity vision.
Together, our work provides an integrated cellular and molecular framework for HAA development. We investigated how gene expression boundaries, and distinct developmental programs potentially converged to create a specialized retinal territory and further used comparative approaches to understand these findings in an evolutionary context. More broadly, our integration of multiplexed imaging with single-cell transcriptomics offers a generalizable strategy for reconstructing spatial patterning logic in developing tissues. This study not only advances our understanding of human foveal development but also offers new tools to study the origins of tissue specialization across systems and species.Biology, Molecular and Cellula
Elucidating the Potential of Networked CD8+ T Cell Epitopes Towards a Functional HIV Cure
No full textThe latent HIV-1 reservoir presents a major obstacle to the cure of HIV infection. While CD8+ T
cells represent a promising modality for viral suppression and eradication, these efforts have been
greatly impeded by the emergence of epitope escape mutations. Recent work from our laboratory
identified a subset of epitopes, known as networked epitopes, which are preferentially targeted
by spontaneous controllers of HIV and mitigate against CD8+ T cell epitope escape due to their
presence at structurally constrained regions of the viral proteome. In this thesis, we investigated
whether networked epitopes exhibited reduced mutational frequencies within the latent reservoir
of people living with HIV (PLWH) on suppressive antiretroviral therapy and thereby could promote
sustained CD8+ T cell recognition and clearance of latently infected cells.
To accomplish this, we performed integrated proviral DNA sequencing and near full-length
individual proviral (FLIP) sequencing on genomic DNA derived from CD4+ T cells from twenty-two
individuals on suppressive antiretroviral therapy (ART), who initiated treatment during chronic
infection. Mutations across all optimal, HLA-restricted, and cytotoxic T lymphocytes (CTL)-
targeted epitopes were quantified using a computational pipeline designed to assess overall,
conservative and non-conservative residue substitutions. From this analysis, we observed that
networked epitopes displayed markedly reduced mutational frequencies compared to non-
networked epitopes in both integrated proviral DNA (p .0001) and near full-length proviral
clones (p.0002) for overall and non-conservative mutations. Moreover, epitope network scores
correlated inversely with mutational frequency, suggesting an association between the degree of
structural epitope constraint and viral escape. Analyses of endogenous CD8+ T cell responses
with PLWH revealed enhanced cross-recognition by T cells for variants of networked epitope, in
contrast to the pronounced loss of recognition observed for mutated non-networked epitopes.
Correspondingly, CD8+ T cell clones directed toward networked epitopes exhibited superior
clearance of reactivated latent CD4+ T cells derived from ART-suppressed individuals.
Together, these findings demonstrate that networked HIV epitopes exhibit reduced immune
escape, superior preservation of CD8+ T cell recognition, and enhanced clearance of the latent
reservoir in comparison to non-networked epitopes. This reveals their potential promise as targets
for therapeutic T cell-based interventions aimed at achieving durable reservoir suppression
following ART cessation.Virolog
Overcoming Heaven: Xu Guangqi and Intellectual Responses to Climatic Crisis in Late Ming China
No full textAbstract
This dissertation examines the scholarship of late Ming intellectual Xu Guangqi (1562–1633), focusing on how the environmental crises of his time were crucial to understanding his work and the broader intellectual landscape of the period. It emphasizes Xu’s lifelong involvement in astronomy and calendrics, agriculture, hydraulics, and mathematics, arguing that these seemingly disparate fields were unified by his relentless pursuit of disaster relief, particularly famine control. While Xu’s scope and synthesis were distinctive, he was part of a broader late-Ming literati movement concerned with disaster relief. These efforts increasingly encompassed southern China.
Through the chapters, I show how Xu’s engagement with heaven, earth, and water was driven by three key concerns: (1) astrological predictions of natural disasters based on accurate astronomical knowledge, (2) famine relief through the cultivation of famine-resistant crops, and (3) water control to mitigate disaster-related damage. The frameworks of the Little Ice Age and the seventeenth-century crisis, as defined by modern environmental historians, provide valuable insight into these efforts.
Chapter One, “Multiple Crises? Xu Guangqi and His Time,” examines Xu’s response to the military, environmental, and demographic crises of his era. While his concerns about military threats, particularly from the Manchu invasions, were largely provisional, the environmental crisis had a lasting impact on his scholarship. The chapter shows how the modern concept of the Little Ice Age helps illuminate the persistent environmental challenges Xu faced throughout his life. Although demographic pressures could have complicated his agricultural initiatives, Xu focused on migration from the south to the north to alleviate population density. This strategy ensured welfare through studies on disaster relief and preparedness, regardless of geographic location.
Chapter Two, “Heaven: Astronomy and Prognostication,” explores the reception of European astrology by Chinese intellectuals, with Xu playing a pioneering role in integrating it into Chinese thought. I argue that Xu viewed European astrology as a tool for predicting natural disasters, challenging traditional Chinese meteorology—particularly through debates over solar and lunar eclipses. I characterize this transition as a shift from a “correlative” (moralist) to a “naturalist” stance and trace the intellectual legacy of Xu’s astrological concerns.
Chapter Three, “Earth: Agriculture and Famine Relief,” examines Xu’s agricultural studies, particularly his promotion of famine-resistant crops like sweet potatoes and turnips across the country. I argue that these initiatives were a direct response to the widespread environmental crisis of the time, which unfolded on a national, and even global, scale. This chapter shows Xu’s empirical rigor and positions his agricultural efforts as an intellectual response to the environmental challenges he faced.
Chapter Four, “Water: Hydraulics and Mathematics,” investigates Xu’s hydraulic work and related mathematical concerns. I distinguish his “artificial” approach to water control from the earlier “naturalist” approach, highlighting his pioneering role in translating Western hydraulic machines. This chapter shows how Xu integrated Western mathematics with traditional Chinese approaches, driven by his practical concerns for land surveying in the construction of hydraulic facilities such as dams, dikes, and reservoirs. In doing so, Xu postulated a fundamental unity between Chinese and Western traditions, laying the groundwork for subsequent scholarship.
Chapter Five, “Overcoming Heaven,” explores Xu’s concept of heaven, which unites his work in astronomy, agriculture, and hydraulics. I argue that his notion of “overcoming heaven”—the belief that heaven can err and must be corrected through human knowledge and interventions—marked a radical departure from the traditional neo-Confucian view of heaven as benevolent, a perspective shared by his contemporaries. I suggest that this redefined understanding of heaven may have paved the way for the introduction of Christianity as an alternative moral foundation.
The dissertation concludes by examining the legacy of Xu’s self-funded efforts in disaster relief, which were part of a broader trend among Jiangnan literati in the late Ming. I argue that these efforts reflect both the failure of the Ming dynasty’s famine administration and the frustration of local literati. In contrast, the Qing court actively engaged in famine relief, incorporating late Ming disaster relief texts into agricultural and famine relief manuals. I suggest that the intellectual legacy of Xu and his contemporaries played a critical role in shaping the Qing dynasty’s success in famine relief effort.East Asian Languages and Civilization
Learning-Based Methods for Recovering Visual Structure
No full textExtracting explicit geometric structure from image data is a prerequisite for understanding visual scenes. This process manifests in 2D as the recovery of curvilinear boundaries that delineate objects. Similarly, in the 3D realm, it involves the derivation of scene surfaces from a set of multiple images. These transformations from images to structured representations are notoriously difficult inverse problems complicated by sparse data, misleading local evidence, and geometric complexity. Historically, approaches to this challenge have tended to bifurcate into two distinct paradigms: "geometry-first" methods that rely on rigorous, but restrictive, mathematical priors; and "learning-first" methods that prioritize data-driven scalability but lack interpretability and struggle to generalize beyond their training sets. This dissertation explores two cases of \textit{structured differentiability}, a synthesis of these paradigms that aims to overcome their limitations by embedding geometric objectives and inductive bias directly into differentiable, learning-based formulations.
First, in the context of boundary detection in 2D images, we introduce a lightweight network that employs a differentiable, geometry-aware attention mechanism to resolve ambiguities and recover from measurement noise. Our model decomposes an image into a field of geometric primitives, thereby preserving the geometric precision of geometry-first methods, while leveraging the inference speed and data-driven scalability of neural networks.
Second, we address the challenge of novel view synthesis, where the goal is to recover underlying surface geometry and appearance from a set of images to predict novel viewpoints. We build upon fast and effective splatting-based methods, which represent scene structure as millions of discrete primitives defined by their shape, color, and opacity. To overcome the limitations of traditional methods, which depend on manual tuning, we propose a probabilistic reformulation of 3D Gaussian Splatting. Rather than relying on the heuristic split-and-prune strategies traditionally used to manage surface primitives, we define a continuous, learnable probability distribution from which primitives are sampled. This transforms the allocation of geometry from a set of rigid, discrete rules into a fully differentiable process, allowing gradient descent to naturally concentrate representational capacity where it is needed most.
Collectively, these contributions demonstrate that coupling data-driven learning with geometrically grounded, differentiable objectives reconciles the interpretability of explicit modeling with the empirical power of deep learning, yielding recovery processes that are efficient, interpretable, and robust to real-world ambiguity.Engineering and Applied Sciences - Engineering Science
Cultivating Trusting Teams: A Mixed-Methods Investigation of Collaborative Learning in Undergraduate Physics
Get PDFDespite the collaborative nature of science and growing emphasis on teamwork in STEM
education, our understanding of how undergraduate students perceive successful teams and develop
psychological safety in these environments remains limited. My dissertation addresses this gap
through interconnected qualitative and quantitative studies examining collaborative learning in
undergraduate physics classrooms.
In the qualitative study, I investigate how undergraduate physics students characterize
successful teams using constructivist grounded theory to analyze 302 student written reflections
collected over three academic terms (Fall 2021-2023). Students identify three key components of
successful teams: effective management practices, positive and supportive interpersonal interactions,
and process-oriented learning. In this analysis, I theorize how the key components of successful
teams foster different types of trust needed for intellectual risk-taking. These findings reveal how
distinct forms of trust serve as essential precursors to students freely sharing ideas, including
uncertain, incomplete, or incorrect ones, which enables the dialectical processes necessary for
effective collaborative learning.
In in the quantitative research and intervention, I examine psychological safety, the shared
belief that a team environment is safe for interpersonal risk-taking, as a critical but understudied
factor in physics education. I identify significant associations between psychological safety and
several key factors: demographic characteristics, goal orientations, and physics self-efficacy. The
analysis reveals that students of minority race/ethnic status experience less psychological safety,
while students with stronger mastery goal orientation experience enhanced psychological safety in
their teams. Building on these findings, I implemented an intervention targeting communication
barriers through structured communication guidelines. The evaluation shows promising evidence
that this targeted intervention positively influences psychological safety levels compared to control
conditions, suggesting that brief, psychologically precise interventions can be valuable tools for
enhancing collaborative dynamics in STEM classrooms.
Together, these qualitative and quantitative studies advance our understanding of
collaborative learning in undergraduate STEM fields. The findings demonstrate that fostering trust
and implementing targeted interventions are central to teaching collaborative skills. This research
also informs how STEM educators can design team experiences that maximize student learning
through meaningful peer interactions.Educatio
Individualizing and Monitoring Ankle Assistance for People Poststroke with Soft Exoskeletons and Exosuits Using Limited Data
No full textExoskeletons and exosuits are wearable robots that can augment the performance of gait in unimpaired users and restore mobility in in people with gait impairments.
Understanding how people who use exoskeletons and exosuits utilize these devices is critical to improving their design and control.
Advances in our understanding of how humans interact with wearable robots on a physiological and biomechanical level have led to the design of rigid and soft exoskeletons and exosuits that can specifically target a single joint or a single activity.
This thesis focuses on the control of exoskeletons and exosuits for assisting people poststroke.
Nearly 80% of people poststroke experience gait impairments, which can lead to low community involvement, an increased risk of trips and falls, and a reduced quality of life.
These impairments are particularly apparent at the ankle joint, where people poststroke present with reduced ankle power and torque generation, as well dorsiflexor weakness.
Therefore, increasing the quality of gait is a common rehabilitation goal of people poststroke.
Exoskeletons and exosuits assisting people poststroke, particularly those assisting the ankle, have been shown to improve the quality of gait in research settings.
However, their translation into clinical practice has been slow.
A key obstacle to clinical adoption is the limitation of quality data available to inform the control of these devices.
Gait in people poststroke is highly heterogeneous and unstable; while there is a large body of literature on sensing gait in unimpaired populations, these approaches may not perform well in people poststroke.
We first present a technique for monitoring gait in people poststroke using inertial measurement units (IMUs) placed on either feet.
We use instantaneous information from both IMUs to correct for bias and drift in acceleration data.
Using this corrected data, we calculate foot position in three dimensional space, providing clinically relevant gait metrics such as walking speed, stride length, foot clearance, and circumduction.
We validate this technique in the lab against optical motion capture data.
Further, we demonstrate the this technique can be used to monitor exosuit-induced changes in gait as a person walks in the community.
A second obstacle to the clinical adoption of exoskeletons and exosuits is the need for individualized control.
It is typical for exoskeleton and exosuit users poststroke to fall into categories of "responders" and "nonresponders"; modes of assistance that work well for one user may not work at all for another.
Here, again, there are limitations in the data available to inform individualization.
Lengthy experiment times can often preclude the use of individualization techniques that work well in unimpaired populations.
To enable individualization, we first present a method of optimizing exosuit assistance profiles offline using previously-recorded data.
We validate that this technique can be used to selectively apply either positive or negative augmentation power to the ankle.
We then demonstrate the people poststroke utilize positive and negative augmentation power differently.
Third, we present a method that streamlines exoskeleton and exosuit design by lowering the number of IMUs required to segment the gait cycle from two to one.
We use a gradient-boosting strategy to train a machine learning model that can predict when the paretic foot is on the ground using information solely from an IMU on the paretic foot.
More, we develop an approach to update this machine learning model with recent data as a user walks in new environments, individualizing gait segmentation to each user's gait patterns.
We validate this approach in one person poststroke walking both on the treadmill and overground.
Together, this thesis presents a series of developments that can be used to (i) inform clinicians and researchers if and how exoskeleton-based interventions change gait in the community, (ii) optimize exosuit assistance to examine the biomechanical and physiological impact of exosuit assistance, and (iii) support community and clinical adoption by simplifying exoskeleton design and adapting gait detection to new environments and interventions.Engineering and Applied Sciences - Engineering Science
Functional diversity of enteric glia in the gastrointestinal tract
No full textThe enteric nervous system (ENS) regulates intestinal motility, immunity, and nutrient absorption,
with glia playing essential roles in these processes. However, it is unclear if different types of glia
in the ENS have distinct functions, akin to glia in the central nervous system. To address this gap,
we developed imaging and sequencing approaches to characterize the cellular behaviors and
transcriptional signatures of glia in different spatial compartments along the radial axis of the small
intestine. First, we developed an intestinal ring imaging preparation to observe glial behaviors in
real time. Using tissues from dual reporter mice (Vil1Cre Rosa26Ai9/+ Plp1eGFP), we found that glia
in the healthy intestine exhibit minimal movement, suggesting largely fixed positions and
morphologies in their local niches. We then developed a technique to perform bulk-RNA
sequencing of glia from the mucosal and muscularis compartments of the small intestine from
Plp1eGFP mice, reasoning glia in these two spatial compartments were likely to be the most distinct.
While the populations shared core glial gene programs, mucosal glia resembled microglia while
muscularis glia were most similar to satellite glia and astrocytes, supporting that enteric glia have
identities that reflect their niche and other glial populations outside of the ENS. We also sought to
ask whether there were defining markers that distinguished enteric glial subpopulations from other
glial cells, which would provide genetic tractability to manipulate these cells. To date, no single
genetic handle exists to target enteric glia without affecting another glial population outside of the
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ENS. We identified that muscularis glia showed selective expression of Tacr3, which encodes a
G-protein coupled receptor for neuropeptides. Using Tacr3IRES-Cre/+ Rosa26Ai9/+ mice to genetically
label Tacr3-expressing cells, we observed that Tacr3 expression emerged in the postnatal ENS.
By 21 days of age, over 95% of tdTomato-labeled cells in the muscularis were glia, primarily the
glia surrounding neuron somas (intraganglionic). Additionally, tdTomato labeling was not detected
in intramuscular or extra-intestinal glia. The restricted expression in intraganglionic glia allowed
us to elucidate the transcriptional signatures of glia in other spatial compartments using single
cell transcriptomics. Both early postnatal TACR3 inhibition and lack of the high affinity ligand NKB
in mice resulted in significant loss of intramuscular glial cells and altered the molecular phenotype
of intraganglionic glia, while mucosal glia remained intact, underscoring the importance of NKB-
TACR3 signaling in ENS development. In adult mice, pharmacological modulation of TACR3
affected gastrointestinal transit, establishing Tacr3+ intraganglionic glia as a distinct population
essential for normal ENS function. During dextran sodium sulfate-induced colitis, Tacr3
expression significantly decreased, and Tac2 haploinsufficient mice showed slower recovery,
suggesting therapeutic potential for enhancing TACR3 signaling in treating intestinal
inflammation. Taken together, these insights not only advance our understanding of glial biology
in the ENS but also have immediate implications for the clinical use of TACR3 inhibitors that are
already on the market for women to manage menopausal hot flashes.Medical Science