Overexpression of miRNA-26a Increases Cell Proliferation in Hepatic Cells Via akt/Beta-Catenin Pathway

Background and Aims: Liver is a uniqueorgandue to its property of regenerating post-injury or partial hepatectomy. However, the mechanisms regulating this process are not clearly understood. miRNAs are 22 nucleotides long, endogenous RNA molecules and can be one of the many molecular regulators of this process. Hence, we hypothesized thatmiRNA-26amay regulate cell proliferation via akt/b-catenin pathway. Methods: Huh7 cells were used for the experiment. MiRNA-26a was over-expressed in these cells using siPORT NeoFX transfection reagent. After 72 h of transfection, the cells were also collected for either RNA or protein isolation. Total RNA enriched with miRNA was isolated, cDNA was synthesized and PCR for b-catenin and cyclin D1. The total cellular protein was used for Western blots for the detection ofGSK3b,b-catenin,Cyclin-D1,Akt,p-Akt, andb-actin. b-Actin was used as an internal control in all the Western blot results. Results:Overexpression of miRNA-26a resulted in an increase in the mRNA level of b-catenin (1.3 fold compared to control) and cyclin-D1 (1.7 fold compared to control). Over expression of miRNA-26a resulted in a down-regulation of GSK3b protein expression (target protein for miRNA-26a), resulting in an increase of both b-catenin and cyclin D1 (3-fold increase compared to control), and p-akt expression (2-fold over control) protein levels. Conclusion: This data demonstrates that miRNA26a positively regulates the expression of b-catenin and cyclin D1 by inhibiting GSK3b. Thus, miRNA26a could play a role in increasing proliferation of the hepatic cells during regeneration.