Placenta-derived mesenchymal stem cells enhance human liver organoid maturation: translational implications for liver regeneration

Abstract

Background & Aim The global prevalence of end-stage liver disease (ESLD) has reached very high levels, and, to date, the best treatment option is orthotopic liver transplantation (1). However, due to the complexity of this procedure and the limited numbers of healthy organ donors, new therapeutic options are being sought. Liver progenitor and multipotent stem cells offer potential cell sources that could be used clinically (2). Different studies have reported therapeutic effects of transplanted mesenchymal stem cells (MSCs) on ESLD (3). Indeed, an improvement of liver function has been achieved in patients with liver cirrhosis after autologous MSCs injection (4). Based on our recent work where we showed that a three-dimensional (3D) culture method is effective to improve MSCs paracrine activity (5), in this work, we used a human liver organoid system to study if the paracrine signal secreted by human amnion-derived MSCs (hAMSCs) affect liver stem/progenitor cells to differentiate (Fig. 1). Epithelial organoids recapitulate multiple aspects of real organs, making them promising models of organ function to model and treat human disease (6). Methods, Results & Conclusion Our data show that the expanded human liver organoids had distinct traits in the ALB production, Krt19 and HNF1β expression when compared to the reference cell line HepG2 cells. On liver organoids, we tested conventional differentiation medium (DM) conditioned by both 2D (2D CM) and 3D (3D CM) hAMSCs cultures observing that ALB, NTCP (markers of mature hepatocytes), and LGR5 (stem cell marker) expression were significantly upregulated by 3D CM compared with both 2D CM and conventional DM. Furthermore, CYP3A4 expression (marker of mature hepatocytes) was upregulated in both 2D and 3D CM. These data were also confirmed by the over-production/activity of both ALB and CYP3A4 observed in organoids grown with 3D CM. Liver epithelial dysfunctional repair play a role in the development of liver disease, and, effective repair likely requires the normal functioning of liver stem/progenitor cells. Herein, we showed that hAMSCs, principally grown in 3D cultures, has the potential to increase hepatic stem/progenitor cell differentiation, demonstrating that soluble factors secreted by hAMSCs are likely responsible for the response. This work revealing a potential approach to improve cell transplantation with the ultimate goal being efficient liver regeneration.