The Type 3 Adenylyl Cyclase Is Required For Intestinal Mucosal Neural Network In The Gut Lamina Propria

Molecular mechanisms associated with adenylate cyclase to maintain the enteric nervous system network remain poorly understood.Type 3 adenylyl cyclase（AC3）is a membrane-bound cyclic adenosine monophosphate（c AMP）producing enzyme expressed in the central nervous system.IAlthough AC3 plays roles in neurogenesis as well as neural dendritic arborization in brain.The functional role of AC3 in the gastrointestinal tract remainds elusive.The aim of this study was to determine whether AC3 has roles in the enteric nervous system（ENS）in the gut lamina propria.And whether the intestinal flora regulates the formation and maintenance of the intestinal nervous system through AC3 and c AMP pathway.We investigated AC3 expression throughout the bowel by immunohistochemistry,RT-PCR using tissues from AC3 wild-type.AC3 knockout mice(AC3^-/-)were used to examine the effect of AC3 absence on the ENS function in the colon compared to those from AC3 WT mice.In addition,total gastrointestinal transit time and Colonic motility were compared between AC3^-/-and AC3^+/+mice.21 days of antibiotic treatment to study whether AC3-c AMP signaling pathway and the gut microbiota jointly affect ENS function in mice.AC3 is predominately expressed in the myenteric plexus of the small and large intestine.By measuring whole-bowel transit and colonic-bead expulsion it showed that intestinal motility was altered in mice with deletion of AC3.Compared with AC3^+/+mice,absence of AC3(AC3^-/-)causes an percentage decrease of nerve fibers and enteric glial cells in colonic mucosa.Further more,AC3^-/-mucosa and submucosa exhibited increase apoptosis levels.We visualized the localization of primary cilium,which also decreased in the gut lamina propria of AC3^-/-mice with antibodies against ARL13B.The innervation of the AC3^-/-mouse colonic mucosa was reduced as the number of nerve fibers in the gut lamina propria was decreased.AC3 and c AMP signaling are possibly required for the development and function of the adult neural network of ENS.After that,we established a pseudo germ-free mice model by feeding AC3^-/-and AC3^+/+mice with mixed antibiotics（ABX）to analyze the innervation ability of the intestinal nervous system to the mucosal layer.It was found that compared with AC3^-/-group,ABX-AC3^-/-group had no superposition effect,indicating that gut microbiome and AC3-c AMP act via independent pathway to regulate host-ENS.