Collagenolytic Potential of Rat Liver Myofibroblasts

Abstract

Rat liver myofibroblasts (MFB) were isolated by repeated passaging of nonparenchymal liver cell fraction. They were cultured on polystyrene Petri dishes, on fibrin or on type I collagen gels for 5 days. Quantitative RT-PCR, Western blotting, zymography and immunocytochemistry were used to study differences in cell morphology and protein expression. MFB were large and spread on plastic substrate, with prominent α-smooth muscle (α-SMA) fibres. They turned much smaller and elongated on collagen which was accompanied by the rearrangement of the cytoskeleton and a decrease in α-SMA and β-actin content. Collagen gel induced the expression of a group of metalloproteinases (MMP-2, -3, -9, -13), on mRNA and protein level which resulted in the degradation of the gel. This response was accompanied by changes in the mRNA expression of cytokines of TGF-β family, CTGF and interleukin-6, as well as of osteopontin and thrombospondin-2 that are involved in metalloproteinases (MMPs) regulation. The expression of MMPs substrates, collagen types I, IV and XII did not change or decreased. The effects of fibrin gels on MFB were milder than those of collagen. MFB assumed to deposit collagen and other ECM components in fibrotic liver, besides hepatic stellate cells, also possess a great collagenolytic potential.

ARHGEF4-mediates the actin cytoskeleton reorganization of hepatic stellate cells in 3-dimensional collagen matrices

“…However, HSCs show a flattened, fibroblast-like shape with well-developed lamellipodia and actin stress fibers when cultured on a 2D polystyrene surface (PS) or on a type I collagen-coated surface, suggesting the regulation of HSC morphology and function by extracellular matrix (ECM) components in the perisinusoidal space of Disse [2][3][4]. In fact, HSCs exhibit an in vivo morphology with long cellular processes when cultured in 3D collagen matrices and do not form clear lamellipodia and actin stress fibers [3,[5][6][7]. Thus, HSCs cultured in 3D collagen matrices may be better able to mimic the morphology and function of HSCs in an in vivo environment.…”