title: Mechanosensory Signaling in Enterochromaffin Cells and 5-HT Release: Potential Implications for Gut Inflammation.
abstract: Enterochromaffin (EC) cells synthesize 95% of the body 5-HT and release 5-HT in response to mechanical or chemical stimulation. EC cell 5-HT has physiological effects on gut motility, secretion and visceral sensation. Abnormal regulation of 5-HT occurs in gastrointestinal disorders and Inflammatory Bowel Diseases (IBD) where 5-HT may represent a key player in the pathogenesis of intestinal inflammation. The focus of this review is on mechanism(s) involved in EC cell "mechanosensation" and critical gaps in our knowledge for future research. Much of our knowledge and concepts are from a human BON cell model of EC, although more recent work has included other cell lines, native EC cells from mouse and human and intact mucosa. EC cells are "mechanosensors" that respond to physical forces generated during peristaltic activity by translating the mechanical stimulus (MS) into an intracellular biochemical response leading to 5-HT and ATP release. The emerging picture of mechanosensation includes Piezo 2 channels, caveolin-rich microdomains, and tight regulation of 5-HT release by purines. The "purinergic hypothesis"is that MS releases purines to act in an autocrine/paracrine manner to activate excitatory (P2Y1, P2Y4, P2Y6, and A2A/A2B) or inhibitory (P2Y12, A1, and A3) receptors to regulate 5-HT release. MS activates a P2Y1/Gαq/PLC/IP3-IP3R/SERCA Ca2+signaling pathway, an A2A/A2B-Gs/AC/cAMP-PKA signaling pathway, an ATP-gated P2X3channel, and an inhibitory P2Y12-Gi/o/AC-cAMP pathway. In human IBD, P2X3is down regulated and A2Bis up regulated in EC cells, but the pathophysiological consequences of abnormal mechanosensory or purinergic 5-HT signaling remain unknown. EC cell mechanosensation remains poorly understood.
authors.affiliation: Department of Anesthesiology, Wexner Medical Center at Ohio State UniversityColumbus, OH, USA; CONACYT-Centro Universitario de Investigaciones Biomedicas, University of ColimaColima, Mexico.
authors.forename: Andromeda
authors.initials: A
authors.lastname: Linan-Rico
authors.affiliation: Department of Anesthesiology, Wexner Medical Center at Ohio State University Columbus, OH, USA.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ochoa-Cortes
authors.affiliation: Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic Rochester, MN, USA.
authors.forename: Arthur
authors.initials: A
authors.lastname: Beyder
authors.affiliation: Department of Anesthesiology, Wexner Medical Center at Ohio State University Columbus, OH, USA.
authors.forename: Suren
authors.initials: S
authors.lastname: Soghomonyan
authors.affiliation: Department of Anesthesiology, Wexner Medical Center at Ohio State University Columbus, OH, USA.
authors.forename: Alix
authors.initials: A
authors.lastname: Zuleta-Alarcon
authors.affiliation: SBS-Cancer Biology and Genetics, Ohio State University Columbus, OH, USA.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Coppola
authors.affiliation: Department of Anesthesiology, Wexner Medical Center at Ohio State University Columbus, OH, USA.
authors.forename: Fievos L
authors.initials: FL
authors.lastname: Christofi
keywords: ENS; Piezo 2; enterochromaffin; inflammation; mechanotransduction; purinergic receptors