The molecular basis of the genesis of basal tone in internal anal sphincter.
Smooth muscle sphincters exhibit basal tone and control passage of contents through organs such as the gastrointestinal tract; loss of this tone leads to disorders such as faecal incontinence. However, the molecular mechanisms underlying this tone remain unknown. Here, we show that deletion of myosin light-chain kinases (MLCK) in the smooth muscle cells from internal anal sphincter (IAS-SMCs) abolishes basal tone, impairing defecation. Pharmacological regulation of ryanodine receptors (RyRs), L-type voltage-dependent Ca(2+) channels (VDCCs) or TMEM16A Ca(2+)-activated Cl(-) channels significantly changes global cytosolic Ca(2+) concentration ([Ca(2+)]i) and the tone. TMEM16A deletion in IAS-SMCs abolishes the effects of modulators for TMEM16A or VDCCs on a RyR-mediated rise in global [Ca(2+)]i and impairs the tone and defecation. Hence, MLCK activation in IAS-SMCs caused by a global rise in [Ca(2+)]i via a RyR-TMEM16A-VDCC signalling module sets the basal tone. Targeting this module may lead to new treatments for diseases like faecal incontinence.
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.|Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Cheng-Hai
CH
Zhang
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.
Pei
P
Wang
Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Dong-Hai
DH
Liu
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.
Cai-Ping
CP
Chen
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.
Wei
W
Zhao
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.
Xin
X
Chen
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.
Chen
C
Chen
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.|CAM-SU Genomic Resource Center, Soochow University, Suzhou 215123, China.
Wei-Qi
WQ
He
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.
Yan-Ning
YN
Qiao
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.
Tao
T
Tao
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.
Jie
J
Sun
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.
Ya-Jing
YJ
Peng
Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Ping
P
Lu
Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Kaizhi
K
Zheng
Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
Siobhan M
SM
Craige
Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Lawrence M
LM
Lifshitz
Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
John F
JF
Keaney
Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Kevin E
KE
Fogarty
Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Ronghua
R
ZhuGe
State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing 210061, China.|Innovation Center for Cardiovascular Disorders, Beijing 100029, China.
Min-Sheng
MS
Zhu
D001003:Anal Canal / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D000075369:Anoctamin-1; D018723:Bethanechol / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism*; D003672:Defecation / Q000187:drug effects; D005242:Fecal Incontinence / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009119:Muscle Contraction / Q000187:drug effects; D009123:Muscle Hypotonia / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D009219:Myosin-Light-Chain Kinase / Q000172:deficiency / Q000235:genetics*; D009543:Nifedipine / Q000494:pharmacology; D009544:Niflumic Acid / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics / Q000378:metabolism*
C531181:ANO1 protein, mouse; D000075369:Anoctamin-1; D020746:Calcium Channels, L-Type; D018118:Chloride Channels; D019837:Ryanodine Receptor Calcium Release Channel; D018723:Bethanechol; D009544:Niflumic Acid; D009219:Myosin-Light-Chain Kinase; D009543:Nifedipine; D002118:Calcium