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MicroRNA-29a mitigation of endoplasmic reticulum and autophagy aberrance counteracts in obstructive jaundice-induced fibrosis in mice.

Authors: Huang, Ying-Hsien  Yang, Ya-Ling  Huang, Fu-Chen  Tiao, Mao-Meng  Lin, Yen-Cheng  Tsai, Ming-Horng  Wang, Feng-Sheng 
Citation: Huang YH, etal., Exp Biol Med (Maywood). 2018 Jan;243(1):13-21. doi: 10.1177/1535370217741500. Epub 2017 Nov 6.
Pubmed: (View Article at PubMed) PMID:29105510
DOI: Full-text: DOI:10.1177/1535370217741500

Hepatic fibrosis was caused by a number of signaling pathways that damage liver integrity. We have previously shown that microRNA-29a (miR-29a) protects against liver fibrosis. Aberrant endoplasmic reticulum (ER) and autophagy function reportedly exaggerate hepatic disorders. The aim of this study was to characterize the biological influence of miR-29a on ER function in injured livers with bile duct ligation (BDL). We performed BDL on miR-29a transgenic mice (miR-29aTg) and wild-type mice to induce cholestatic liver injury. Rat T6 cells were transfected with miR-29a mimic and tunicamycin. Compared to the wild-type mice, the BDL deterioration of liver function in terms of total bilirubin, alanine transaminase, and aspartate transaminase activity in the miR-29aTg mice was significantly reduced. Affected livers in the miR-29aTg mice demonstrated a slight fibrotic matrix formation. miR-29a over-expression reduced the BDL disturbance of the expressions of inositol-requiring kinase 1alpha, double-stranded RNA-activated protein kinase-like endoplasmic reticulum kinase, spliced-X-box binding protein 1 (sXBP1), CCAAT/enhancer-binding protein homologous protein (CHOP), ULK, LC3BII, p62, and cleaved caspase-8, 9 and 3. In vitro, T6 cells exposed to tunicamycin by increasing abundances of CHOP, sXBP1, cleaved caspase-3, and LC3BII were diminished in the cell cultures transfected with the miR-29a mimic. On the other hand, we observed that miR-29a signaling protected liver tissues from BDL-mediated metabolic dysfunction and excessive fibrosis histopathology. This study provides new molecular insight into the miR-29a stabilization of ER integrity that slows the progression of cholestatic liver deterioration. Impact statement Long-term hepatic damage caused by hepatitis and cholestasis can accelerate fibrosis matrix over-production, which is a harmful process attributed to the dysregulation of a number of cellular and molecular events. The purpose of this study is to characterize the biological influence of miR-29a on endoplasmic reticulum (ER) function in bile duct ligation (BDL)-injured livers. To the best of our knowledge, this report is the first demonstration that miR-29a over-expression diminishes BDL provocation of ER stress (unfolded protein response, UPR) effector protein expression. This work also demonstrates that miR-29a decreased caspases protein expression in cholestatic livers, while an increase in miR-29a function reduced sXBP1 and CHOP expressions in T6 cells in mice. Analyses of this study highlight that controlling miR-29a signaling can serve as an innovative strategy in the future for microRNA regulation of ER homeostasis to combat cholestasis induction hepatic disorders.


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RGD Object Information
RGD ID: 13782297
Created: 2018-09-04
Species: All species
Last Modified: 2018-09-04
Status: ACTIVE


RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.