Actomyosin contractility drives bile regurgitation as an early response during obstructive cholestasis

Kapish Gupta; Qiushi Li; Jun Jun Fan; Eliza Li Shan Fong; Ziwei Song; Shupei Mo; Haoyu Tang; Inn Chuan Ng; Chan Way Ng; Pornteera Pawijit; Shuangmu Zhuo; Chen-Yuan Dong; Boon Chuan Low; Aileen Wee; Yock Young Dan; Pakorn Kanchanawong; Peter So; Virgile Viasnoff; Hanry Yu

doi:10.1016/j.jhep.2017.01.026

Actomyosin contractility drives bile regurgitation as an early response during obstructive cholestasis

J Hepatol. 2017 Jun;66(6):1231-1240. doi: 10.1016/j.jhep.2017.01.026. Epub 2017 Feb 9.

Authors

Kapish Gupta¹, Qiushi Li², Jun Jun Fan³, Eliza Li Shan Fong⁴, Ziwei Song⁵, Shupei Mo⁵, Haoyu Tang¹, Inn Chuan Ng⁶, Chan Way Ng⁶, Pornteera Pawijit⁷, Shuangmu Zhuo⁸, Chen-Yuan Dong⁹, Boon Chuan Low¹⁰, Aileen Wee¹¹, Yock Young Dan¹², Pakorn Kanchanawong¹³, Peter So¹⁴, Virgile Viasnoff¹⁵, Hanry Yu¹⁶

Affiliations

¹ Mechanobiology Institute, National University of Singapore, Singapore.
² Mechanobiology Institute, National University of Singapore, Singapore; National University of Singapore Research Institute, Singapore.
³ Institute of Bioengineering and Nanotechnology, Agency for Science, Technology and Research (A*STAR), Singapore; BioSyM, Singapore-MIT Alliance for Research and Technology, Singapore; Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, China.
⁴ Department of Physiology, National University of Singapore, Singapore; Department of Biomedical Engineering, National University of Singapore, Singapore.
⁵ Institute of Bioengineering and Nanotechnology, Agency for Science, Technology and Research (A*STAR), Singapore.
⁶ Department of Physiology, National University of Singapore, Singapore.
⁷ Department of Physiology, National University of Singapore, Singapore; NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore, Singapore.
⁸ BioSyM, Singapore-MIT Alliance for Research and Technology, Singapore; Fujian Normal University, Fuzhou, Fujian, China.
⁹ Department of Physics, National Taiwan University, Taiwan.
¹⁰ Mechanobiology Institute, National University of Singapore, Singapore; Department of Biological Sciences, National University of Singapore, Singapore.
¹¹ Department of Pathology, National University of Singapore, Singapore.
¹² Division of Gastroenterology and Hepatology, National University Hospital, Singapore.
¹³ Mechanobiology Institute, National University of Singapore, Singapore; Department of Biomedical Engineering, National University of Singapore, Singapore.
¹⁴ BioSyM, Singapore-MIT Alliance for Research and Technology, Singapore.
¹⁵ Mechanobiology Institute, National University of Singapore, Singapore; CNRS UMI3639, Singapore.
¹⁶ Mechanobiology Institute, National University of Singapore, Singapore; Institute of Bioengineering and Nanotechnology, Agency for Science, Technology and Research (A*STAR), Singapore; BioSyM, Singapore-MIT Alliance for Research and Technology, Singapore; Department of Physiology, National University of Singapore, Singapore; Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China. Electronic address: hanry_yu@nuhs.edu.sg.

PMID: 28189756
DOI: 10.1016/j.jhep.2017.01.026

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 (2-8μm). 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.

Keywords: Actomyosin cortex; Bile; Bile canaliculi; Blebs; Cholestasis; Hepatocytes; Vesicles.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Actomyosin / physiology*
Animals
Bile Canaliculi / pathology
Bile Canaliculi / physiopathology
Bile Ducts / physiopathology*
Bile Reflux / physiopathology
Biomechanical Phenomena
Cholestasis / pathology
Cholestasis / physiopathology*
Disease Models, Animal
Male
Mice
Mice, Transgenic
Pressure
Rats
Rats, Wistar

Substances

Actomyosin

Grants and funding

P41 EB015871/EB/NIBIB NIH HHS/United States