The Effects Of CXCL14 In Carbon Tetrachloride Induced Liver Injury

CXCL14 is a member of CXC chemokine family, it selectively performs chemotaxis on monocytes, dendritic cells and natural killer cells. CXCL14 is considerably diverged from the other family members on protein primary structure, however, it is very conversed between orthologous genes of different species. It lost a conserved“ELR”motif at the NH2-terminal of primary structure, which possibly causes the angiostatic activity and anticarcinoma activity. Recently, scientists have focused on its functions on tumorigenesis and fatty acid metabolism.The study of CXCL14 on liver injury was still not reported. The previous transcription profile data by gene microarray denoted that cxcl14 transcription level was highly increased in CCl4 induced liver injury model, which implied the involvement of CXCL14 in the pathological process. Based on this clue, we primarily investigated the transcription profile of cxcl14 more precisely and comprehensively in three model using fluorescence quantitative PCR on CCl4 induced acute liver injury model, alcohol induced liver fibrosis model and partial hepatectomy model. Next, we investigated the function of CXCL14 on acute liver injury by plasmid-mediated overexpression and immunoneutralization-mediated knock-down expression. And then we established the method for expression and high-scale purification of recombinant mouse CXCL14 protein. Finally, we preliminarily investigated the interaction of CXCL14 and members of CXCR receptors. The results indicated that CXCL14 expression was increased significantly in all investigated disease models, the peak values reached the 30 fold of normal value in CCl4 induced acute injury model (p < 0.001), 6 fold in fibrosis model (p < 0.05) and 4.5 fold in partial hepatectomy model (p < 0.05). The overexpression of CXCL14 significantly aggravated CCl4 induced liver injury, including aggravated the acidophilic change of hepatocytes (p < 0.05) in early phase (0 ~ 0.5 d); aggravated the hepatocytes necrosis (p < 0.05), steatosis (p < 0.001) and peroxidation level in middle phase (0.5~2 d); and delayed the hepatocyte peroliferation (p < 0.01) in later phase (after 2 d). In contrast, the CXCL14 immuno-neutralization reduced the injuries in varied aspects, the most significantly, reduced the hepatic steatosis (p < 0.01) and hepatocyte proliferation (p < 0.05). Additionally, CXCL14 neutralization significantly increased the survival of CCl4 induced liver failure mice (71% v.s. 42%, p < 0.05).In conclusion, CXCL14 is up-regulalted in liver injury period, the over-expressed CXCL14 aggravates the injury in turn. The immuno-neutralization of CXCL14 improves CCl4 induced injury and finally increase the survival of CCl4 induced liver failure mice. CXCL14 regulates the preoxidation of hepatocyte and enhence the liver injury by a autocrine or endocrine form. We also established the CXCL14 purification method by denaturation-renaturation strategy, by this method micrograms of high puritfied (> 95%) CXCL14 protein was perpared with bioactivity from 1 liter of E.coli culture, providing reliable recombinant protein for further animal experiment. Using this prepared protein, we investigated the interaction of CXCL14 with members of CXCR receptor family preliminarily, with the result that CXCL14 showed the highest affinity with CXCR1 and CXCR4 and almost no affinity with CXCR3. The result layed a foundation for identifying specific receptor(s) of CXCL14.