Shifting into high gear: how interstitial cells of Cajal change the motility pattern of the developing intestine

Abstract

The first contractile waves in the developing embryonic gut are purely myogenic, they only involve smooth muscle. Here, we provide evidence for a transition from smooth-muscle to Interstitial Cell of Cajal (ICC) driven contractile waves in the developing chicken gut. In-situ hybridization staining for ANO1, a known ICC marker, shows that ICCs are already present throughout the gut as from embryonic day 7 (E7). We devised a protocol to reveal ICC oscillatory and propagative calcium activity in embryonic gut whole-mount and find that the first steady calcium oscillations in ICCs occur at E14. We show that the activation of ICCs leads to an increase in contractile wave frequency, regularity, directionality and velocity between E12 and E14. We finally demonstrate that application of the c-KIT antagonist imatinib mesylate in organ culture specifically depletes the ICC network and inhibits the transition to a regular, rhythmic wave pattern. We compare our findings to existing results in the mouse and predict that a similar transition should take place in the human fetus between 12 and 14 weeks of development. Together, our results point to an abrupt physiological transition from smooth-muscle mesenchyme self-initiating waves to ICC-driven motility in the fetus, and clarify the contribution of ICCs to the contractile wave pattern.

The origin and mechanisms of smooth muscle cell development in vertebrates

“…They regulate peristalsis: the involuntary movement of the longitudinal and circular muscles that occur in progressive wavelike contractions in esophagus, stomach and intestines allowing movement of food through the digestive system. Studies in chicken and zebrafish embryos have described the emergence, propagation and physiological-molecular development of SM-dependent gut peristalsis in the lower digestive tract (Abrams et al, 2012;Chevalier et al, 2020Chevalier et al, , 2017Gays et al, 2017). During murine embryonic development, it has been shown that iSMCs confer shape and mobility of the intestine through peristaltic movements (Gabella, 2002), facilitated by the presence of circumferential and longitudinal layers of iSMCs that wrap around the gut tube (Kedinger et al, 1990).…”

Distribution map of peristaltic waves in the chicken embryonic gut reveals importance of ENS and inter-region cross talks along the gut axis

“…The chicken embryonic gut serves as a simplified experimental system enabling high resolution analyses because they undergo peristalsis even before hatching (no food contents in the gut). Chevalier et al recently reported that the activity of gut peristalsis becomes higher at E12 onward, where networks between interstitial cells of Cajal, ENS and smooth muscles may become mature (Chevalier et al, 2020). Although analyzing guts post E12 is currently beyond our capabilities due to gut's massive increase in length, it is important to know how the spatial patterns of peristalsis evolve and mature during late development.…”

“…Chevalier and co-workers reported pioneering studies using chicken embryonic guts, in which they described changes in speed and frequencies of local peristaltic waves during development (Chevalier et al, 2020;Chevalier et al, 2019;Chevalier et al, 2017). They observed irregular and discontinuous contractions in early embryos at E5, which was followed by emergence of peristaltic propagations around E7.…”

“…The embryonic chicken gut serves as an excellent model system when working toward this goal, as the gut undergoes peristalsis even before hatching (no feeding), and also because gut-constituting cells and tissues are easily manipulable experimentally. Chevalier and co-workers reported pioneering studies using chicken embryonic guts, in which they described changes in speed and frequencies of local peristaltic waves during development (Chevalier et al, 2020; Chevalier et al, 2019; Chevalier et al, 2017). They observed irregular and discontinuous contractions in early embryos at E5, which was followed by emergence of peristaltic propagations around E7.…”

DOG1 is commonly expressed in pancreatic adenocarcinoma but unrelated to cancer aggressiveness

“…DOG1 (Discovered On Gastrointestinal Stromal Tumors Protein 1), also known as Transmembrane Protein 16A (TMEM16A) or Anoctamin-1 (ANO1) is a voltage-gated calcium-activated chloride and bicarbonate channel ( Caputo et al, 2008 ; Yang et al, 2008 ). DOG1 is highly expressed in the gastrointestinal interstitial cells of Cajal, where it plays an important role in epithelial chloride secretion mediating intestinal motility ( Miettinen, Wang & Lasota, 2009 ; Chevalier et al, 2020 ). Calcium-activated chloride channel blocking drugs like niflumic acid have been shown to block slow waves (pacemaker activity)—which produce motility—in the human small intestine and stomach ( Hwang et al, 2009 ).…”