Hepatic stellate cells contribute to liver regeneration through galectins in hepatic stem cell niche

Abstract

Background As a critical cellular component in the hepatic stem cell niche, hepatic stellate cells (HSCs) play critical roles in regulating the expansion of hepatic stem cells, liver regeneration, and fibrogenesis. However, the signaling of HSCs, particularly that involved in promoting hepatic stem cell expansion, remains unclear. While the overexpression of galectins has been identified in regenerating liver tissues, their involvement in cell-cell interactions between HSCs and hepatic stem cells remains to be elucidated. Methods To generate a liver regeneration rat model and establish a hepatic oval cell microenvironment as a stem cell niche, 2-acetylaminofluorene treatment plus partial hepatectomy was performed. Immunofluorescence staining was conducted to detect the emergence of hepatic stem cells and their niche. Liver parenchymal cells, non-parenchymal cells, and HSCs were isolated for gene and protein expression analysis by qPCR or western blotting. To evaluate the effect of galectins on the colony-forming efficiency of hepatic stem cells, c-Kit−CD29+CD49f+/lowCD45−Ter-119− cells were cultured with recombinant galectin protein, galectin antibody, galectin-producing HSCs, and galectin-knockdown HSCs. Results Following liver injury, the cytokeratin 19+ ductal cells were robustly induced together with the emergence of OV6+CD44+CD133+EpCAM+ hepatic stem cells. The activated desmin+ HSCs were recruited around the periportal area and markedly enriched in the galectin-positive domain compared to the other non-parenchymal cells. Notably, the HSC fraction isolated from regenerating liver was accompanied by dramatically elevated gene and protein expression of galectins. Hepatic stem cells co-cultured with HSCs significantly enhanced colony-forming efficiency. Conversely, single or double knockdown of galectin-1 and galectin-3 led into a significant function loss, impaired the co-cultured hepatic stem cells to attenuated colony size, inhibited colony frequency, and reduced total cell numbers in colonies. On the other hand, the promotive function of galectins was further confirmed by recombinant galectin protein supplementation and galectins blocking antibodies. Conclusions Our findings, for the first time, demonstrated that galectins from activated HSCs contribute to hepatic stem cell expansion during liver regeneration, suggesting that galectins serve as important stem cell niche components.

Hepatic galectin-3 is associated with lipid droplet area in non-alcoholic steatohepatitis in a new swine model

“…Since LGALS3, galectin-3, has emerged as a canonical 62 and noncanonical inflammasome activator in macrophages 68 and has been found in myeloid-derived cells 23 , it is plausible that activation LGALS3 in Kupffer cells is an early event in the cascade of events taking place in the progression from hepatic simple steatosis into NASH. However, in rats, hepatic stellate cells production of galectin-3 contributes to the expansion of hepatic progenitor cells 69 . Galectin-3 also regulates the capacity of dendritic cells to support killer T-cell-mediated liver injury, playing an important pro-inflammatory role in acute liver injury 70 .…”

Molecular Mechanisms and Potential New Therapeutic Drugs for Liver Fibrosis

“…As research has progressed and understanding of the role of HSCs in disease has increased, we have found that HSCs have a role in promoting liver cell regeneration (Yang et al, 2008), which may be achieved mainly through the following mechanisms, secretion of cytokines that promote liver cell proliferation, promote the migration of stem cells to the liver, and promote the epithelial transformation of mesenchymal cells into hepatocytes. Therefore, we need to consider their role in liver regeneration when targeting HSCs in liver fibrosis (Ge et al, 2020).…”

Role of Immune Cells in Biliary Repair

“…The LPC niche comprises hepatic stellate cells (HSCs), macrophages and other immune cells, endothelial cells, and extracellular matrix (ECM) ( 37 – 39 ). Based on their adjacent distributions, HSCs ( 31 , 40 , 41 ) and macrophages ( 31 , 42 – 44 ) can regulate parenchymal infiltration and differentiation orientation of LPC by intimate cellular crosstalk. In addition, ECM composition and remodeling during liver injury were also found to be crucial to LPC expansion and activation ( 45 , 46 ).…”