Piezo-1 & 2’s role in murine intestinal muscularis cells of the SIP syncytium

This grant application aims to identify and characterize the role of Piezo in cells of the muscularis during baseline and stretched states. Bowel motility disorders and acute bouts of bowel obstruction are common clinical problems and can be severe, and we do not fully understand their mechanisms or have effective treatments. One crucial mechanism controlling bowel motility is mechanosensing, allowing each bowel segment to sense and respond to stretch. Various cell types within the intestinal muscularis control motility, sense stretch, and induce contractions. Among these cells are the components of the SIP syncytium comprised of smooth muscle cells (SMC), interstitial cells of Cajal (ICC), and PDGFRcells. These cells respond to stretch and receive inputs from enteric neurons (EN), glia, and enteroendocrine cells (EEC) that modulate SIP syncytium activity. However, the mechanism underlying the ability to sense and respond to stretch has not been thoroughly evaluated. Here we propose to investigate the role of Piezo in this process. Piezo is a relatively new calcium channel that functions as a mechanosensor in numerous cells, including those in the gut. Here, we will focus on its role in smooth muscle cells, interstitial cells of Cajal, and PDGFRcells of the small intestine. To perform these experiments, we have developed novel methods to maintain murine cells of the muscularis in an in vitro system. We will also use physiologically tunable hydrogels to examine the consequences of stretch in this setting. Finally, we will use various genetic approaches to explore the effects of mechanosensing in SIP cells of the gut. After this study, we anticipate that we will further elucidate the biomechanical and physiological consequences of disrupting a mechanosensitive channel that alters muscularis function and highlight myopathy's indirect effect on the adjacent epithelial layer to exacerbate the dysmotility further.