Liver cell swelling leads to upregulation of miR-141-3p in perfused rat liver and primary rat hepatocytes

Introduction Small persistent changes in liver cell hydration can occur in response to ambient osmolarity, hormones, cumulative amino acid uptake or oxidative stress. Alterations of cell hydration critically contribute to changes in cell functions as well as gene expression. Cell swelling is considered as an anabolic trigger, leads to an inhibition of proteolysis, choleresis, proliferation and is obligatory during liver cell regeneration. On the other hand, cell shrinkage is a catabolic signal and can sensitize towards apoptosis through activation of the CD95 system. In this study we investigated whether miRNAs play a role in hypoosmolarity-induced liver cell swelling.

Methods Rat livers were perfused with either normo- or hypoosmotic fluid in a non-recirculating system over a time course of 180 min. For cell culture experiments hepatocytes were isolated from rat livers by a collagenase perfusion technique. Cultured primary rat hepatocytes were treated with normo- or hypoosmotic medium over a time course of 24 h. Microarray analysis was conducted to screen microRNAs that are differentially expressed in rat livers, which were hypo- (225 mosm/L) and normoosmotically (305 mosm/L) perfused for 180 min. Putative target mRNAs were analyzed via qPCR after 180 min of either hypo- or normoosmotic rat liver perfusion. In rat liver perfusion specific inhibitors for Erk (PD098059; 500 nM), p38 MAPK (PD169316; 250 nM) and microtubules (colchicine, 500 nM) were used.

Results A total of 728 microRNAs were identified, from which 70 were up- and 63 were downregulated in response to hypoosmotic exposure. Specifically, hypoosmotic exposure led to a significant upregulation of miR-141-3p in perfused rat liver as well as primary rat hepatocytes. It was also identified that several putative target mRNAs of miR-141-3p were downregulated after 180 min of hypoosmotic exposure, including Slc39a10 and Dstyk. After addition of PD098059, PD169316 and colchicine, hypoosmolarity-induced upregulation of miR-141-3p was inhibited.

Conclusion Our data indicate that miR-141-3p upregulation is responsive to hypoosmotic stress and that it might contribute to proliferative effects of hypoosmolarity-induced hepatic cell swelling controlled by its target genes. It is shown that both Erk and p38 MAPK play a key role in the hypoosmotic upregulation of miR-141-3p.

This study was supported by the SFB974 and the research commission of HHU.

Publication History

Article published online:
04 January 2021