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Raghavan, S. A.

Publications and source records attributed to Raghavan, S. A..

2 recordsLinked to original sources

Immune-Competent 3D Bioengineered Colons for Functional Interrogation of Neuroinflammation-Induced Colonic Dysmotility

Functional gastrointestinal disorders (FGIDs) affect [~]40% of the global population and are frequently characterized by colonic dysmotility. Symptomatic manifestations of colonic dysmotility significantly reduce quality of life in inflammatory bowel disease (IBD), diabetes, and Gulf War Illness (GWI). Current in vitro models lack the integration of functional physiology with immune and neuronal complexity required to establish causal links between neuroinflammation and dysmotility. Here, an immune-competent bioengineered colon assembloid is introduced that integrates multiple cell types of the external colonic wall, along with functional readouts of motility. Within bioengineered colon assembloids, various inflammatory insults resulted in enteric neuroinflammation, cascading to changes in colonic motility. Key mechanisms of dysmotility following inflammatory insult within the bioengineered colon assembloids included impaired neuronal regeneration, and aberrant smooth muscle remodeling. The bioengineered colon assembloid model mimicked diverse aspects of enteric neuroinflammation. Ultimately, the platform offers a physiologically relevant avenue to interrogate neuroimmune crosstalk and dissect mechanisms of colonic dysmotility, paving the way to new therapeutic strategies to improve colonic motility.

bioengineering↗

Endothelial cell Piezo1 promotes vascular smooth muscle cell differentiation on large arteries

Vascular stabilization is a mechanosensitive process, in part driven by blood flow. Here, we demonstrate the involvement of the mechanosensitive ion channel, Piezo1, in promoting arterial accumulation of vascular smooth muscle cells (vSMCs) during zebrafish development. Using a series of small molecule antagonists or agonists to temporally regulate Piezo1 activity, we identified a role for the Piezo1 channel in regulating klf2a levels and altered targeting of vSMCs between arteries and veins. Increasing Piezo1 activity suppressed klf2a and increased vSMC association with the cardinal vein, while inhibition of Piezo1 activity increased klf2a levels and decreased vSMC association with arteries. We supported the small molecule data with in vivo genetic suppression of piezo1 and 2 in zebrafish, resulting in loss of transgelin+ vSMCs on the dorsal aorta. Further, endothelial cell (EC)-specific Piezo1 knockout in mice was sufficient to decrease vSMC accumulation along the descending dorsal aorta during development, thus phenocopying our zebrafish data, and supporting functional conservation of Piezo1 in mammals. To determine mechanism, we used in vitro modeling assays to demonstrate that differential sensing of pulsatile versus laminar flow forces across endothelial cells changes the expression of mural cell differentiation genes. Together, our findings suggest a crucial role for EC Piezo1 in sensing force within large arteries to mediate mural cell differentiation and stabilization of the arterial vasculature.

developmental biology↗