Effect of substrate stiffness on hepatocyte migration and cellular Young's modulus

Abstract

Hepatic fibrosis progress accompanied by an unbalanced extracellular matrix (ECM) degradation and deposition leads to an increased tissue stiffness. Hepatocytes interplay with all intrahepatic cell populations inside the liver. However, how hepatocytes migration and cellular Young's modulus influenced by the substrate stiffness are not well understood. Here, we established a stiffness-controllable in vitro cell culture model by using a polyvinyl alcohol (PVA) hydrogel that mimicked the same physical stiffness as a fibrotic liver. Three levels of stiffness were used in our experiment that corresponded to the stiffness levels found in normal liver tissue (4.5 kPa), the early (19 kPa) and late stages (37 kPa) of fibrotic liver tissues. Cytoskeleton of hepatocyte was influenced by substrate stiffness. Soft substrate promoted the cellular migration and directionality. The cellular Young's modulus firstly increased and then decreased with increasing substrate stiffness. Integrin-β1 and β-catenin expression on cytomembrane were up-regulated and down-regulated with the increase of substrate stiffness, respectively. Our data not only suggested that hepatocytes were sensitive to substrate stiffness, but also suggested that there may be a potential relationship among substrate stiffness, cellular Young's modulus and the dynamic balance of integrin-β1 and β-catenin pathways. These results may provide us a new insight in mechanism investigation of mechano-dependent diseases, especially like fibrosis related diseases.

The Effect of Matrix Stiffness on Human Hepatocyte Migration and Function—An In Vitro Research

“…PVA hydrogel was prepared as our previous study [ 18 ]. Briefly, 8% ( w/v ) PVA solution was made; for example, 32 g PVA powder (Aladdin, Los Angeles, CA, USA) was dissolved into 400 mL distilled water at 90 °C.…”

Lipid droplets disrupt mechanosensing in human hepatocytes

“…Eighty to ninety percent of HCC cases arise in a stiff, cirrhotic liver (1,12,17), and high liver stiffness correlates strongly with an increased risk of HCC (1,15,20,28). Tissue stiffness is a contributing factor to cancer development in many tissues (2,4,27), and in vitro studies with hepatocytes show that gene expression, motility, and cell stiffness are altered in response to substrate stiffness (31,32). Hepatocytes cultured on a stiff matrix dedifferentiate, with decreased albumin production and glycogen storage and disruption of the HNF4-α transcriptional network (8).…”

Current progress in hepatic tissue regeneration by tissue engineering

“…The soft matrix actively promoted cell migration and alignment. Young's modulus value and integrin β1 content were decreased by increasing matrix stiffness [117]. These results give deep Hosseini et al J Transl Med (2019) 17:383 insights to cell biologists in designing improved matrices with abilities to enhance differentiation efficiency.…”

“…Stem cells differentiated toward hepatic lineage on soft matrices (stiffness = 0.4 kPa) demonstrated a high degree of hepatocyte characteristic within a few hours, whereas stiffer matrices (stiffness > 80 kPa) was unable to support differentiation. Integrins have been suggested play an important role in hepatic induction of stem cells and the matrices with moderate stiffness enhance cellcell (catenin-based) and cell-matrix (integrin-based) adhesion through maintaining balanced regulation of integrin-β1 and β-catenin expression and exhibit high value of Young's modulus [117].…”