Mesenchymal stem cell alleviate primary biliary cirrhosismice by down regulating autophagy of in-trahepatic biliary epithelial cells via signal transducer and activator of transcription 3

Abstract

Objective To investigate the abnormality of intrahepatic biliary epithelial cells autophagy in primary biliary cirrhosis (PBC) mice, and explore the mechanism of UC-Mesenchymal stem cell (MSCs) in treating PBC. Methods After establishing the PBC model, we divided them into the PBC model group; the UC-MSCs treatment group and the Stattic group [Signal transducer and activator of transcription 3 (STAT3) inhibitor group]. Six mice were used as the control group. Liver pathology and the serum pyruvate dehydrogenase complex E2 subunit (PDC-E2) antibody titers were detected. Autophagosome of the intrahepatic biliary epithelial cell was observed by electronic microscope. Protein levels of STAT3/pSTAT3, Beclin-1 were detected by western blot. We cultured human intrahepatic biliary epithelial cells in vitro, and down regulated STAT3. After stimulated by GCDC, we co-cultured them with UC-MSCs, and collected the cells in order to detect LC3Ⅱ. The measurement data were compared with t test or single factor analysis of variance. Results Compared with the control group, periportal inflammatory cell infiltration and granuloma formation were observed in the PBC group. MSCs treatment decreased the infiltration of inflammatory cells. The level of anti-PDC-E2 of the PBC group (107±18) ng/ml was higher than that of the control group (42±6) ng/ml (q=6.326, P 0.05). Western blot showed that the level of Beclin-1 was higher in PBC group(1.80±0.36) than the control group(0.40±0.20) (q=6.757, P<0.01),MSCs reduced the expression of Beclin-1 (0.86±0.06)(q=4.536, P<0.05) as well as Stattic (0.72±0.03) (q=5.226, P<0.05). PBC group had a higher expression level of STAT3 (1.80±0.42)(q=5.730, P<0.05) and pSTAT3(2.04±0.29)(q=6.492, P<0.01) than the control group(0.50±0.05)(0.91±0.14). MSCs treatment decreased the expression of STAT3(0.51±0.13)(q=5.703, P<0.01) and pSTAT3 (0.76±0.07)(q=7.388, P<0.01) in intrahepatic biliary epithelial cells. After down regulated STAT3 of HiBECs, MSCs reduced the expression of LC3Ⅱ of HiBECs. Conclusion The intrahepatic biliary epithelial cells autophage of PBC mice is abnormal, MSCs can alleviate PBC by down regulating the autophage of intrahepatic biliary epithelial cells via STAT3. Key words: Mesenchymal stem cell; Primary biliary cirrhosis; Autophagy; Signal transducer and activator of transcription 3