Actomyosin contractility drives bile regurgitation as an early response during obstructive cholestasis
Journal
Journal of Hepatology
Journal Volume
66
Journal Issue
6
Pages
1231-1240
Date Issued
2017
Author(s)
Gupta, K.
Li, Q.
Fan, J.J.
Fong, E.L.S.
Song, Z.
Mo, S.
Tang, H.
Ng, I.C.
Ng, C.W.
Pawijit, P.
Zhuo, S.
Dong, C.-Y.
Low, B.C.
Wee, A.
Dan, Y.Y.
Kanchanawong, P.
So, P.
Viasnoff, V.
Abstract
Background & Aims A wide range of liver diseases manifest as biliary obstruction, or cholestasis. However, the sequence of molecular events triggered as part of the early hepatocellular homeostatic response in obstructive cholestasis is poorly elucidated. Pericanalicular actin is known to accumulate during obstructive cholestasis. Therefore, we hypothesized that the pericanalicular actin cortex undergoes significant remodeling as a regulatory response to obstructive cholestasis. Methods In vivo investigations were performed in a bile duct-ligated mouse model. Actomyosin contractility was assessed using sandwich-cultured rat hepatocytes transfected with various fluorescently labeled proteins and pharmacological inhibitors of actomyosin contractility. Results Actomyosin contractility induces transient deformations along the canalicular membrane, a process we have termed inward blebbing. We show that these membrane intrusions are initiated by local ruptures in the pericanalicular actin cortex; and they typically retract following repair by actin polymerization and actomyosin contraction. However, above a certain osmotic pressure threshold, these inward blebs pinch away from the canalicular membrane into the hepatocyte cytoplasm as large vesicles (2–8 μm). Importantly, we show that these vesicles aid in the regurgitation of bile from the bile canaliculi. Conclusion Actomyosin contractility induces the formation of bile-regurgitative vesicles, thus serving as an early homeostatic mechanism against increased biliary pressure during cholestasis. Lay summary Bile canaliculi expand and contract in response to the amount of secreted bile, and resistance from the surrounding actin bundles. Further expansion due to bile duct blockade leads to the formation of inward blebs, which carry away excess bile to prevent bile build up in the canaliculi. © 2017 European Association for the Study of the Liver
Subjects
Actomyosin cortex; Bile; Bile canaliculi; Blebs; Cholestasis; Hepatocytes; Vesicles
SDGs
Other Subjects
actin; myosin adenosine triphosphatase; myosin adenosine triphosphatase; actin polymerization; animal cell; animal experiment; animal model; Article; bile canaliculus; bile reflux; cell size; cell vacuole; cholestasis; controlled study; cytoplasm; in vivo study; liver cell culture; mouse; nonhuman; osmotic pressure; priority journal; animal; bile duct; bile reflux; biomechanics; cholestasis; disease model; male; pathology; pathophysiology; physiology; pressure; rat; transgenic mouse; Wistar rat; Actomyosin; Animals; Bile Canaliculi; Bile Ducts; Bile Reflux; Biomechanical Phenomena; Cholestasis; Disease Models, Animal; Male; Mice; Mice, Transgenic; Pressure; Rats; Rats, Wistar
Type
journal article