Inhibition of inhibitor of κB kinases stimulates hepatic stellate cell apoptosis and accelerated recovery from rat liver fibrosis

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

“…Diminution of IkBa is also a requirement for transdifferentiation since this leads to reprogramming of basal NF-kB activity to elevated levels that enable the myofibroblast to express proinflammatory genes and to become resistant to apoptosis. 11,26 DNA methylation therefore exerts control over the key fibrogenic (PPARg) and inflammatory (IkBa) transcriptional regulators of the myofibroblast phenotype. We recently reported a repression mechanism that operates at the IkB-a promoter during MTD of HSC involving the recruitment of the transcriptional repressor CBF1 (RBP-Jk) to an overlapping NF-kB/CBF1 site.…”

“…Liver fibrosis was generated by 5-week treatment of adult male Sprague-Dawley (200-225 g) rats with CCl 4 (CCl 4 /olive oil, 1 : 1(vol/vol) per kg body weight by intraperitoneal injection twice weekly) as previously described. 11 Vehicle control animals were treated intraperitoneally with 1 ml of olive oil/kg body weight at same time intervals. At 24 h after the final CCl 4 administration, animals were culled by CO 2 asphyxiation and liver samples prepared.…”

“…Taqman primers and probes for 18S RNA, TIMP1 and procollagen I were as previously described. 11 Taqman quantitative RT-PCR reactions were composed of template cDNA, 0.3 mmol/l of forward, reverse and probe primers as well as 12.5 ml of Taqman master mix (Applied Biosystems, Europe) in a final volume of 25 ml. Reaction conditions were 501C for 2 min and 951C for 10 min, followed by denaturing for 15 s at 951C and annealing and extension temperature at 601C for 1 min and 40 cycles.…”

“…7,10 HSC-derived HM are transitionary components of the hepatic wound healing response, however, their persistence and proliferation in chronic liver disease promotes the progressive remodelling of the hepatic ECM from normal to fibrotic and eventually cirrhotic tissue. 10,11 The HSC exists as a quiescent retinoidstoring element of the liver that has a perisinusoidal location in the Space of Disse. 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. 7,13 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.…”