TRPV4 Channel Signaling in Macrophages Promotes Gastrointestinal Motility via Direct Effects on Smooth Muscle Cells

• Published in: Immunity (Cambridge, Mass.) Vol. 49; no. 1; pp. 107 - 119.e4
• Main Authors: Luo, Jialie, Qian, Aihua, Oetjen, Landon K., Yu, Weihua, Yang, Pu, Feng, Jing, Xie, Zili, Liu, Shenbin, Yin, Shijin, Dryn, Dari, Cheng, Jizhong, Riehl, Terrence E., Zholos, Alexander V., Stenson, William F., Kim, Brian S., Hu, Hongzhen
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 17-07-2018; Elsevier Limited
• Subjects: Animals; Chemical stimuli; chemogenetics; Chemotherapy; Clonal deletion; Colon; Colon - physiology; Colon - physiopathology; Contraction; COX-1; CX3C Chemokine Receptor 1 - metabolism; CX3CR1; Cyclooxygenase 1 - deficiency; Cyclooxygenase 1 - metabolism; Dinoprostone - analysis; Dinoprostone - metabolism; E-prostanoid receptor; Enteric nervous system; Feces; Female; Gastric motility; Gastric Mucosa - cytology; Gastrointestinal Motility; Gene Expression; Homeostasis; Intestinal motility; Intestine; Irritable bowel syndrome; Macrophages; Macrophages - metabolism; Male; Membrane Proteins - antagonists & inhibitors; Membrane Proteins - deficiency; Membrane Proteins - metabolism; Mice; Mice, Knockout; Motility; Muscle Contraction; Muscles; muscularis macrophage; Myocytes, Smooth Muscle - metabolism; Nervous system; optogenetics; Organic chemistry; Paracrine signalling; Pharmacology; Prostaglandin E; Prostaglandin E2; Receptors, Prostaglandin E - antagonists & inhibitors; Receptors, Prostaglandin E - metabolism; Signal Transduction; Smooth muscle; Transient receptor potential proteins; TRPV Cation Channels - antagonists & inhibitors; TRPV Cation Channels - deficiency; TRPV Cation Channels - genetics; TRPV Cation Channels - metabolism; TRPV4; gastrointestinal motility; CX3CR1; muscularis macrophage; prostaglandin E2; COX-1; TRPV4; optogenetics; chemogenetics; E-prostanoid receptor
• ISSN: 1074-7613; 1097-4180
• DOI: 10.1016/j.immuni.2018.04.021

Intestinal macrophages are critical for gastrointestinal (GI) homeostasis, but our understanding of their role in regulating intestinal motility is incomplete. Here, we report that CX3C chemokine receptor 1-expressing muscularis macrophages (MMs) were required to maintain normal GI motility. MMs expressed the transient receptor potential vanilloid 4 (TRPV4) channel, which senses thermal, mechanical, and chemical cues. Selective pharmacologic inhibition of TRPV4 or conditional deletion of TRPV4 from macrophages decreased intestinal motility and was sufficient to reverse the GI hypermotility that is associated with chemotherapy treatment. Mechanistically, stimulation of MMs via TRPV4 promoted the release of prostaglandin E2 and elicited colon contraction in a paracrine manner via prostaglandin E receptor signaling in intestinal smooth muscle cells without input from the enteric nervous system. Collectively, our data identify TRPV4-expressing MMs as an essential component required for maintaining normal GI motility and provide potential drug targets for GI motility disorders.
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•Macrophage-specific Trpv4-deficient mice display reduced gastrointestinal motility•Direct interactions between MMs and smooth muscle cells produce colon contraction•Enteric nervous system is not involved in macrophage-mediated colon contraction•TRPV4 inhibition reverses GI hypermotility associated with chemotherapy treatment
How intestinal macrophages regulate intestinal motility remains poorly understood. Luo et al. demonstrate that muscularis macrophages expressing the TRPV4 channel promote GI motility by directly affecting the function of intestinal smooth muscle cells independent of the enteric nervous system.