Embryonic liver fodrin involved in hepatic stellate cell activation and formation of regenerative nodule in liver cirrhosis.
Bottom Line: In activated HSCs in vitro, reduction of ELF expression mediated by siRNA leads to the inhibition of HSC activation and procollagen I expression.BrdU assay demonstrates that down-regulation of ELF expression does not inhibit proliferation of activated HSCs in vitro.Further study reveals that HPC expansion occurs as an initial phase, before the reduction of ELF expression in regenerative hepatocytes.
Affiliation: Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.Show MeSH
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Mentions: As described earlier, we demonstrated that hepatic inflammatory reaction and chemical damage did not take any effect on the reduction of ELF expression in CCl4-treated mice. It indicated that ELF was involved in regeneration of hepatocytes nodule in cirrhotic liver. Immunostaining of CK19, a HPC marker revealed that a dramatic expansion of CK19-positive cell in cirrhotic mice compared with normal and ALI mice (Fig. 4A), which indicated that HPC contributed to regeneration of hepatocytes nodules in cirrhotic liver. To determine the ability of mature hepatocytes to proliferate in cirrhotic liver, we performed Ki67 staining of liver sections from mice receiving CCl4 treatment. We saw a rapid burst in Ki67-positive hepatocytes in mice receiving CCl4 treatment at day 7, which revealed the proliferation of mature hepatocytes. Later, it decreased significantly as a result of the loss of mature hepatocytes proliferation upon repeated liver injury, and then increased remarkably from day 56, which revealed HPC proliferation (Fig. 4B). All these demonstrated that regenerative nodules of hepatocytes were derived from HPC expansion. To confirm the relation between HPC expansion and the reduction of ELF expression in regenerative hepatocytes, we performed the timeline-based study on hepatic expression of CK19 and ELF in CCl4-treated mice. After day 7, HPC activation assessed by CK19 staining was observed in damaged liver, either isolated or forming small clusters consisting of two to three cells; from day 14, CK19-positive cells were more numerous, forming clusters that contained an increasing number of cells (Fig. 4C and E). Although ELF expression in isolated hepatocytes from CCl4-treated mice decreased remarkably at day 28 (Fig. 4D and F). Thereafter, the reduction of ELF in regenerative hepatocytes over time was consistent with HPC expansion. All these indicated that activation of HPC occurred as an initial phase, before the reduction of ELF expression in regenerative hepatocytes, which was derived from HPC differentiation.
Affiliation: Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.