Connexin 32 and connexin 43 are involved in lineage restriction of hepatic progenitor cells to hepatocytes

Abstract

BackgroundBi-potential hepatic progenitor cells can give rise to both hepatocytes and cholangiocytes, which is the last phase and critical juncture in terms of sequentially hepatic lineage restriction from any kind of stem cells. If their differentiation can be controlled, it might access to functional hepatocytes to develop pharmaceutical and biotechnology industries as well as cell therapies for end-stage liver diseases.MethodsIn this study, we investigated the influence of Cx32 and Cx43 on hepatocyte differentiation of WB-F344 cells by in vitro gain and loss of function analyses. An inhibitor of Cx32 was also used to make further clarification. To reveal p38 MAPK pathway is closely related to Cxs, rats with 70% partial hepatectomy were injected intraperitoneally with a p38 inhibitor, SB203580. Besides, the effects of p38 MAPK pathway on differentiation of hepatoblasts isolated from fetal rat livers were evaluated by addition of SB203580 in culture medium.ResultsIn vitro gain and loss of function analyses showed overexpression of Connexin 32 and knockdown of Connexin 43 promoted hepatocytes differentiation from hepatic progenitor cells. In addition, in vitro and ex vivo research revealed inhibition of p38 mitogen-activated protein kinase pathway can improve hepatocytes differentiation correlating with upregulation of Connexin 32 expression and downregulation of Connexin 43 expression.ConclusionsHere we demonstrate that Connexins play crucial roles in facilitating differentiation of hepatic progenitors. Our work further implicates that regulators of Connexins and their related pathways might provide new insights to improve lineage restriction of stem cells to mature hepatocytes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-017-0703-2) contains supplementary material, which is available to authorized users.

Connexin Expression Is Altered in Liver Development of Yotari (dab1 -/-) Mice

“…At the same time, looking at Cx32 expression our results display higher levels in both phases compare to Cx43. In more recent study, switch from Cx43 to Cx32 production was shown during hepatocytes differentiation of fetal hepatic progenitor cells from rats and moreover, inhibition of p38 MAPK pathway advance this process [60]. Contrary to our result where we got decline in Cx43 expression in yotari E13.5 compared to wt, in rodent liver overdosed with acetaminophen Cx43 is upregulated.…”

Connexin 43 Gene Ablation Does Not Alter Human Pluripotent Stem Cell Germ Lineage Specification

“…Conversely, expression of Cx32 markedly decreases in the early stages of adipose-derived stem cell differentiation [ 54 ]. Interestingly, overexpression of Cx32 and knockdown of Cx43 promotes hepatocyte differentiation, highlighting the dynamic relationship between GJIC and cell fate specification [ 26 ]. Therefore, it is apparent that Cxs are important for the maintenance and downstream specification of somatic stem cell populations.…”

“…Dissecting how GJIC contributes to the differentiation of downstream cell types has been challenging. For instance, human ESC differentiation towards hepatocytes relies on Cx32 expression but is further promoted by Cx43 downregulation [ 25 , 26 ]. Cx43 is reportedly upregulated during human ESC differentiation toward endoderm, and continued Cx43 activity promotes differentiation to endoderm-derived pancreatic precursors [ 27 ].…”

Role of connexin 32 in the directional differentiation of induced pluripotent stem cells into hepatocytes

“…Diverse types of connexins, including connexin 32 (Cx32) and connexin 26 (Cx26), are found in well-organized tissue of the adult liver, and these construct a GJIC network between hepatocytes and are essential for functional differentiation [14]. Notably, it has been reported that overexpression of Cx32 promotes the differentiation of hepatic progenitor cells into hepatocytes [15]. Cx32-mediated cell-cell communication serves a crucial role in hepatic differentiation from human embryonic stem cells (hESCs) [16].…”