Niacin downregulates chemokine (c-c motif) ligand 2 (CCL2) expression and inhibits fat synthesis in rat liver cells

Purpose: To elucidate the role of chemokine (c-c motif) ligand 2 (CCL2) in fat metabolism in hepatocytes. Methods: Following partial hepatectomy, regenerated rat liver cells were isolated and cultured for 24 h were transfected with recombinant plasmid pEGFP-N1-CCL2 using liposomes. Niacin was added to the culture medium to inhibit fat synthesis. CCL2 expression was measured using western blot, while the expression of acly-coa synthetase long chain family 4 (ACSL4) and apolipoprotein E (ApoE) were assessed using real-time PCR. Results: At 12 h after transfection, GFP-positive rates in the pEGFP-N1 and pEGFP-N1-CCL2 transfection groups were 42.4 ± 5.6 % and 45.1 ± 3.5 %, respectively. Expression levels of CCL2 increased over time in pEGFP-N1 transfection group, pEGFP-N1-ccl2 transfection group, and niacin and pEGFP-N1-ccl2 transfection co-treatment group; however, CCL2 expression levels in the niacin and pEGFP-N1-ccl2 transfection co-treatment groups were similar to that of pEGFP-N1 transfection group, which were significantly lower than those of the pEGFP-N1-ccl2 transfection group. Expressionlevel trends of fat-related genes ACSL4 and ApoE were similar to that of CCL2. Conclusion: Niacin downregulates the expression of CCL2, thereby inhibiting lipid synthesis in liver cells. Keywords: Chemokine 2, Niacin, Hepatectomy, Lipid synthesis, Transfection