CaM kinase II in colonic smooth muscle contributes to dysmotility in murine DSS-colitis.
BACKGROUND
Altered calcium mobilization has been implicated in the development of colonic dysmotility in inflammatory bowel disease. The aim of this study was to investigate the mechanisms by which disrupted intracellular Ca(2+) signalling contributes to the impaired contractility of colon circular smooth muscles.


METHODS
Acute colitis was induced in C57Bl/6 mice with dextran sulphate sodium (DSS) in the drinking water for 5 days.


RESULTS
Spontaneous and acetylcholine-evoked contractions, caffeine-evoked hyperpolarization, and SERCA2 and phospholamban expression were reduced compared with controls. Tetrodotoxin did not restore control levels of contractile activity. The amplitudes, but not the frequency, of intracellular Ca(2+) waves were increased compared with controls. Caffeine abolished intracellular Ca(2+) waves in control smooth muscle cells, but not in smooth muscle cells from DSS-treated mice. CaM kinase II activity and cytosolic levels of HDAC4 were increased, and I kappaB alpha levels were decreased in distal colon smooth muscles from DSS-treated mice.


CONCLUSIONS
These results suggest that disruptions in intracellular Ca(2+) mobilization due to down-regulation of SERCA2 and phospholamban expression lead to increased CaM kinase II activity and cytosolic HDAC4 that may contribute to the dysmotility of colonic smooth muscles in colitis by enhancing NF-kappaB activity.
Qureshi
S
S
Department of Physiology and Cell Biology, Center of Biomedical Research Excellence, University of Nevada School of Medicine, Reno, NV 89557, USA.
Song
J
J
Lee
H-T
HT
Koh
S D
SD
Hennig
G W
GW
Perrino
B A
BA
D000109:Acetylcholine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D015153:Blotting, Western; D002110:Caffeine / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002135:Calcium-Binding Proteins / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism*; D003092:Colitis / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology*; D003106:Colon / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D016264:Dextran Sulfate / Q000633:toxicity; D015536:Down-Regulation; D004594:Electrophysiology; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism; D013997:Time Factors; D000099211:Phospholamban
D000109:Acetylcholine; D002110:Caffeine; D002135:Calcium-Binding Proteins; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D016264:Dextran Sulfate; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000099211:Phospholamban; C506947:Atp2a2 protein, mouse