MicroRNA-29a protects against acute liver injury in a mouse model of obstructive jaundice via inhibition of the extrinsic apoptosis pathway.
Recent studies have shown that microRNA-29 (miR-29) is significantly decreased in liver fibrosis, as demonstrated in human liver cirrhosis, and that its downregulation influences the activation of hepatic stellate cells. In addition, both cleaved caspase-3 production and apoptosis play a role in cholestatic liver injury. However, it is unknown if miR-29 is effective in modulating the extent of injury. We employed miR-29a transgenic mice (miR-29aTg mice) and wild-type (WT) littermates to clarify the role of miR-29 in hepatic injury and fibrogenesis, using the bile duct-ligation (BDL) mouse model. After BDL, all three members of the miR-29 family were significantly downregulated in the livers of WT mice, and miR-29b and miR-29c were significantly downregulated in the livers of the miR-29aTg mice. Liver function, as measured by alanine transaminase and aspartate transaminase activity, was significantly improved in the miR-29aTg mice than in the WT littermates, following 1 week of obstructive jaundice. In addition, overexpression of miR-29a was associated with a significant downregulation of the expression of collagen-1α1, collagen-4α1, phospho-FADD, cleaved caspase-8, cleaved caspase-3, Bax, Bcl-2, PARP, and nuclear factor-κB, as well as an upregulation of phospho-AKT expression. In addition, there were significantly fewer TUNEL-positive liver cells in the miR-29aTg group than in the WT littermates after BDL. Our results indicate that miR-29a decreases cholestatic liver injury and fibrosis after BDL, at least partially, by modulating the extrinsic rather than intrinsic pathway of apoptosis.
Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and the Graduate Institute of Clinical Medical Sciences, Chang Gung University College of Medicine, 123 Ta-Pei Road, Niao-Sung District, Kaohsiung, 833, Taiwan, ROC.
Mao-Meng
MM
Tiao
Feng-Sheng
FS
Wang
Li-Tung
LT
Huang
Jiin-Haur
JH
Chuang
Ho-Chang
HC
Kuo
Ya-Ling
YL
Yang
Ying-Hsien
YH
Huang
D000818:Animals; D017209:Apoptosis; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D002779:Cholestasis / Q000378:metabolism; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D006801:Humans; D041781:Jaundice, Obstructive / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology / Q000517:prevention & control*; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism
C547014:MIRN29 microRNA, mouse; D035683:MicroRNAs; D019253:Proto-Oncogene Proteins c-bcl-2; D003094:Collagen; D053148:Caspase 3