Efficient generation of functional hepatocytelike cells from mouse liver progenitor cells via indirect co-culture with immortalized human hepatic stellate cells

BACKGROUND： Differentiation of liver progenitor cells（LPCs） to functional hepatocytes holds great potential to develop new strategies for hepatocyte transplantation and the screening of drug-induced cytotoxicity. However, reports on the efficient and convenient hepatic differentiation of LPCs to hepatocytes are few. The present study aims to investigate the possibility of generating functional hepatocytes from LPCs in an indirect co-culture system.METHODS： Mouse LPCs were co-cultured in Transwell plates with an immortalized human hepatic stellate cell line（HSCLi） we previously established. The morphology, expression of hepatic markers, and functions of mouse LPC-derived cells were monitored and compared with those of conventionally cultured LPCs. RESULTS： Co-culturing with HSC-Li cells induced differentiation of mouse LPCs into functional hepatocyte-like cells. The differentiated cells were morphologically transformed into hepatocyte-like cells 3 days after co-culture initiation. In addition, the differentiated cells expressed liver-specific genes and possessed hepatic functions, including glycogen storage, lowdensity lipoprotein uptake, albumin secretion, urea synthesis, and cytochrome P450 1A2 enzymatic activity.CONCLUSIONS： Our method, which employs indirect co-culture with HSC-Li cells, can efficiently induce the differentiation of LPCs into functional hepatocytes. This finding suggests that this co-culture system can be a useful method for the efficient generation of functional hepatocytes from LPCs.

Regeneration and activation of liver progenitor cells in liver cirrhosis

Cirrhosis is characterized as the progress of regenerative nodules surrounded by fibrous bands in response to chronic hepatic injury and causes portal hypertension and end-stage hepatic disease.Following liver injury,liver progenitor cells(LPCs)can be activated and differentiate into hepatocytes in order to awaken liver regeneration and reach homeosta-sis.Recent research has uncovered some new sources of LPCs.Here,we update the mecha-nisms of LPCs-mediated liver regeneration in cirrhosis by introducing the origin of LPCs and LPCs’niche with a discussion of the influence of LPC-related cells.This article analyzes the mechanism of regeneration and activation of LPCs in cirrhosis in recent years aiming to provide help for clinical application.

Human liver stem/progenitor cells decrease serum bilirubin in hyperbilirubinemic Gunn rat

AIM: To test the ability of adult-derived human liver stem/progenitor cells (ADHLSC) from large scale cultures to conjugate bilirubin in vitro and in bilirubin conjugation deficient rat.

road to stemness in hepatocellular carcinoma

Carcinogenic process has been proposed to relay on the capacity to induce local tissue damage and proliferative repair. Liver has a great regeneration capacity and currently, most studies point towards the dominant role of hepatocytes in regeneration at all levels of liver damage. The most frequent liver cancer is hepatocellular carcinoma(HCC). Historical findings originally led to the idea that the cell of origin of HCC might be a progenitor cell. However, current linage tracing studies put the progenitor hypothesis of HCC origin into question. In agreement with their dominant role in liver regeneration, mature hepatocytes are emerging as the cell of origin of HCC, although, the specific hepatocyte subpopulation of origin is yet to be determined. The relationship between the cancer cell of origin(CCO) and cancer-propagating cells, known as hepatic cancer stem cell(HCSC) is unknown. It has been challenging to identify the definitive phenotypic marker of HCSC, probably due to the existence of different cancer stem cells(CSC) subpopulations with different functions within HCC. There is a dynamic interconversion among different CSCs, and between CSC and non-CSCs. Because of that, CSC-state is currently defined as a description of a highly adaptable and dynamic intrinsic property of tumor cells, instead of a static subpopulation of a tumor. Altered conditions could trigger the gain of stemness, some of them include: EMT-MET, epigenetics, microenvironment and selective stimulus such as chemotherapy. This CSC heterogeneity and dynamism makes them out reach from therapeutic protocols directed to a single target. A further avenue of research in this line will be to uncover mechanisms that trigger this interconversion of cell populations within tumors and target it.

Role of Liver Progenitor Cell in Liver Regeneration Cellular Cross-Talks and Signals

The liver is well known for its ability to regenerate in response to injury. After partial hepatectomy and some chemicals induced acute liver injury, existing hepatocytes can expand to repair the liver function. While adult liver stem/progenitor cells(LPCs) are evoked and differentiate into functional hepatocytes and cholangiocytes to compensate the damaged liver once hepatocyte proliferation is severely impaired. A number of evidences suggest that adjacent hepatic stellate cells(HSCs) or invading leukocytes may be involved in LPCs directed regeneration through governning two major events including fibrogenic and inflammatory responses respectively or simultaneously. As such, a microenvironment(or "niche") composed of different cell sources or factors presents diversity, which eventually mediates LPCs response to biliary or hepatocellular regeneration. This mini review aims at summarizing the latest development on the roles of HSCs, macrophages and lymphocytes as well as corresponding signaling pathways in liver progenitor cells mediated biliary and hepatocellular regeneration, and discussing therapeutic potential of liver progenitor cells in hepatic diseases.

Hepatocyte generation in liver homeostasis, repair, and regeneration

The liver has remarkable capability to regenerate,employing mechanism to ensure the stable liver-to-bodyweight ratio for body homeostasis.The source of this regenerative capacity has received great attention over the past decade yet still remained controversial currently.Deciphering the sources for hepatocytes provides the basis for understanding tissue regeneration and repair,and also illustrates new potential therapeutic targets for treating liver diseases.In this review,we describe recent advances in genetic lineage tracing studies over liver stem cells,hepatocyte proliferation,and cell lineage conversions or cellular reprogramming.This review will also evaluate the technical strengths and limitations of methods used for studies on hepatocyte generation and cell fate plasticity in liver homeostasis,repair and regeneration.

Transcription networks in liver development and acute liver failure

Acute liver failure(ALF)is a medical emergency due to massive hepatocyte loss.In such a harsh condition,maintaining transcriptional regulation in the remaining hepatocytes while activating similar transcription factor networks in liver progenitor cells(LPCs)to ensure essential liver functions are two critical processes to rescue patients from liver failure and death.In this review,we discuss the formation and functions of transcription networks in ALF and liver development.We focus on a hierarchical network of transcription factors that responds to different pathophysiological circumstances:(1)Under normal circumstances,pioneer factor forkhead box protein A2(FOXA2)coordinates several constitutive hepatic transcription factors,such as hepatic nuclear factor 4 alpha(HNF4a)and CCAAT-enhancer binding protein a(C/EBPa),which ensure normal liver function;(2)When the expression of both HNF4a and C/EBPa in hepatocytes are disrupted by severe inflammation,retinoic acid receptor(RAR)is the alternative transcription factor that compensates for their absence;(3)When massive hepatic necrosis occurs,a similar transcription network including FOXA2 and HNF4a,is activated as a“rescue network”in LPCs to maintain vital liver functions when hepatocytes fail,and thus ensures survival.Expression of these master transcription factors in hepatocytes and LPCs is tightly regulated by hormone signals and inflammation.The performance of this hierarchical transcription network,in particularly the“rescue network”described above,significantly affects the clinical outcome of ALF.