Gene expression profiling and secretome analysis differentiate adult-derived human liver stem/progenitor cells and human hepatic stellate cells

INTRODUCTION:Adult-derived human liver stem/progenitor cells (ADHLSC) are isolated after primary culture of liver parenchymal fraction. The cells are currently developed as potential alternative to hepatocyte for liver cell based therapies. ADHLSC are of fibroblastic morphology and exhibit a hepato-mesenchymal phenotype. Hepatic stellate cells (HSC) isolated from the liver non-parenchymal fraction present a comparable morphology as ADHLSC and are described as liver stem/progenitor cells. AIMS&METHODS:In the current work, we strived to extensively compare both cell populations and to propose tools demonstrating their singularity. ADHLSC and HSC were isolated from the liver of four different donors, expanded in vitro and followed from passage 5 until passage 11. Cell characterization was performed using immunocytochemistry, flow cytometry, and gene microarray analyses. The secretion profile of the cells was evaluated using Elisa and multiplex Luminex assays. RESULTS:Both cell types expressed α-smooth muscle actin, vimentin, fibronectin, CD73 and CD90, in accordance with their mesenchymal origin. Microarray analysis revealed significant differences in gene expression profiles. HSC present high expression levels of neuronal markers as well as cytokeratins. Such differences were confirmed using immunocytochemistry. Both cell types also display distinct secretion profiles as ADHLSC highly secreted cytokines of therapeutic and immuno-modulatory importance, like HGF, interferon gamma and IL-10. Finally, ADHLSC and HSC behave differentially when incubated with specific growth factors involved in hepatogenic differentiation. CONCLUSION:Our study demonstrates that, even sharing several phenotypic characteristics, ADHLSC and HSC are distinct liver fibroblastic cell populations as they exhibit significant different intrinsic gene expression and secretion profiles. This study confirms the promising future of ADHLSC in liver regenerative medicine