Requirement of Gαq/Gα11 Signaling in the Preservation of Mouse Intestinal Epithelial Homeostasis

Noboru Watanabe; Hirosato Mashima; Kouichi Miura; Takashi Goto; Makoto Yoshida; Akiteru Goto; Hirohide Ohnishi

doi:10.1016/j.jcmgh.2016.08.001

Requirement of Gα_q/Gα₁₁ Signaling in the Preservation of Mouse Intestinal Epithelial Homeostasis

Cell Mol Gastroenterol Hepatol. 2016 Aug 22;2(6):767-782.e6. doi: 10.1016/j.jcmgh.2016.08.001. eCollection 2016 Nov.

Authors

Noboru Watanabe¹, Hirosato Mashima², Kouichi Miura¹, Takashi Goto¹, Makoto Yoshida³, Akiteru Goto³, Hirohide Ohnishi¹

Affiliations

¹ Department of Gastroenterology and Hepato-Biliary-Pancreatology, Akita University Graduate School of Medicine, Akita, Japan.
² Department of Gastroenterology and Hepato-Biliary-Pancreatology, Akita University Graduate School of Medicine, Akita, Japan; Department of Gastroenterology, Saitama Medical Center, Jichi Medical University, Saitama, Japan.
³ Department of Pathology, Akita University Graduate School of Medicine, Akita, Japan.

Abstract

Background & aims: Proliferation, differentiation, and morphogenesis of the intestinal epithelium are tightly regulated by a number of molecular pathways. Coordinated action of intestine is achieved by gastrointestinal hormones, most of which exert these actions through G-protein-coupled receptors. We herein investigated the role of Gα_q/11-mediated signaling in intestinal homeostasis.

Methods: Intestinal tissues from control (Gnaq^flox/floxGna11^+/+ ), Int-G_q knock-out (KO) (VilCre^+/-Gnaq^flox/floxGna11^+/+ ), G₁₁ KO (Gnaq^flox/floxGna11^-/- ), and Int-G_q/G₁₁ double knock-out (DKO) (VilCre^+/-Gnaq^flox/floxGna11^-/- ) mice were examined by microscopy, transmission electron microscopy, and immunohistochemistry. The effect of Gα_q/11-mediated signaling was studied in the cell lineage, proliferation, and apoptosis. Dextran sodium sulfate (DSS) colitis was induced to study the role of Gα_q/11 in colon.

Results: Paneth cells were enlarged, increased in number, and mislocalized in Int-Gq/G11 DKO small intestine. Paneth cells also reacted with PAS and Muc2 antibody, indicating an intermediate character of Paneth and goblet cells. The nuclear β-catenin, T-cell factor 1, and Sox9 expression were reduced severely in the crypt base of Int-Gq/G11 DKO intestine. Proliferation was activated in the crypt base and apoptosis was enhanced along the crypt. Int-Gq/G11 DKO mice were susceptible to DSS colitis. Proliferation was inhibited in the crypt of unaffected and regenerative areas. Cystic crypts, periodic acid-Schiff-positive cells, and Muc2-positive cells were unusually observed in the ulcerative region.

Conclusions: The Gα_q/11-mediated pathway plays a pivotal role in the preservation of intestinal homeostasis, especially in Paneth cell maturation and positioning. Wnt/β-catenin signaling was reduced significantly in the crypt base in Gα_q/G₁₁-deficient mice, resulting in the defective maturation of Paneth cells, induction of differentiation toward goblet cells, and susceptibility to DSS colitis.

Keywords: Atoh1, atonal homolog 1; BrdU, bromodeoxyuridine; DSS, dextran sodium sulfate; Defa1, defensin α1; Dll1, delta-like 1; FGF, fibroblast growth factor; Fzd, frizzled; Gna11; Gnaq; Hes, hairy/enhancer of split; IEC, intestinal epithelial cell; Ihh, Indian hedgehog; Intermediate Cell; NICD, Notch intracellular cytoplasmic domain; PAS, periodic acid–Schiff; PCR, polymerase chain reaction; PKC, protein kinase C; Paneth Cell; TEM, transmission electron micrograph; TUNEL, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling; Tcf, T-cell factor; Wnt; mRNA, messenger RNA; qPCR, quantitative real-time polymerase chain reaction.