Genomic and functional characterization of stellate cells isolated from human cirrhotic livers

Regulation of myofibroblast transdifferentiation by DNA methylation and MeCP2: implications for wound healing and fibrogenesis

“…[14][15][16][17][18] These dramatic functional changes are associated with a global reprogramming of the HSC transcriptome, including the up-and downregulation of several hundred different genes. 12 Similar dramatic changes in phenotype are described for MTD occurring in the kidney, pancreas and lung indicating that a common transcriptional reprogramming process may operate to generate myofibroblasts in response to tissue injury. [2][3][4] In support of this concept there are many reports describing alterations in expression and/or activity of key transcription factors such as PPARs, NF-kB and AP-1 common to MTD of distinct organ-specific myofibroblast-precursor cells.…”

“…HSC can be isolated and purified from normal rodent liver (described in Materials and Methods) and upon culture on plastic in serum-containing media spontaneously transdifferentiate into a myofibroblastic cell in a manner that closely resembles MTD events occurring in the injured liver. 7,[12][13] By employing this well-established in vitro model of MTD, we showed that MeCP2 mRNA expression was increased during transdifferentiation of HSC (Figure 2a). Moreover, Western blot analysis of MeCP2 revealed that the protein was not expressed at detectable levels in quiescent HSC but was powerfully induced during culture-induced MTD of these cells (Figure 2a).…”

“…Cultured HSC loose their vitamin A, enter the cell cycle and display de novo expression of a wide variety of profibrogenic and proinflammatory molecules that are characteristic of HM and which are described in detail elsewehere. 7,[12][13] Rat HSC and the LX2 human stellate cell line 25 were cultured on plastic in Dulbecco's modified Eagle's medium (DMEM), supplemented with 100 U/ml penicillin, 100 mg/ml streptomycin, 2 mM L-glutamine, and 16% or 10% fetal calf serum, respectively. Cell cultures were maintained at 371C at an atmosphere of 5% CO 2 .…”

“…The MTD or so-called 'activation' of HSC generates a highly proliferative, contractile, smooth musclealpha actin (a-SMA) positive cell that acquires a plethora of biochemical and functional phenotypic characteristics not observed with the quiescent HSC. 7,12,13 Transition of HSC to the myofibroblastic phenotype is most readily studied by a widely accepted and reproducible in vitro model in which freshly isolated rodent or human HSC are cultured on plastic in the presence of serum-containing medium. 7,[10][11][12][13] This cell culture model recapitulates events occurring in the injured liver and enables the earliest events of MTD and the functional characteristics of the HSC-derived myofibroblast to be analysed in fine detail.…”

“…7,12,13 Transition of HSC to the myofibroblastic phenotype is most readily studied by a widely accepted and reproducible in vitro model in which freshly isolated rodent or human HSC are cultured on plastic in the presence of serum-containing medium. 7,[10][11][12][13] This cell culture model recapitulates events occurring in the injured liver and enables the earliest events of MTD and the functional characteristics of the HSC-derived myofibroblast to be analysed in fine detail. 7,13 HSC-derived myofibroblasts are highly profibrogenic and secrete vast quantities of collagen I and III as well as the tissue-inhibitor of metalloproteinases-1 (TIMP-1) which combine to promote collagen deposition.…”