Palmitic acid inhibits proliferation of pancreatic β cell line INS-1 via up-regulating expression of receptors Frizzled-2 and Ror-2

AIM:To investigate the mechanism of palmitic acid inhibiting the proliferation of rat pancreatic β cell line INS-1. METHODS:INS-1 cells were treated with palmitic acid in time or concentration gradient experiments. The expression of Frizzled-2 (Fzd-2) and receptor tyrosine kinase-like orphan receptor 2 (Ror-2) at mRNA and protein levels was detected by RT-qPCR and Western blot. Interaction of Wnt5a with Fzd-2 or Ror-2 in INS-1 cells treated with palmitic acid was determined by the method of direct co-immunoprecipitation. The proliferation rates of the cells were measured by EdU assay after transfected with siRNA-Fzd-2 or siRNA-Ror-2. RESULTS:Fzd-2 and Ror-2 were up-regulated in INS-1 cells stimulated with palmitic acid at both mRNA and protein levels. Palmitic acid promoted Wnt5a to recruit receptors Fzd-2 and Ror-2. Silencing the expression of Fzd-2 or Ror-2 weakened the inhibitory effect of palmitic acid on INS-1 cell proliferation (P<0.05). CONCLUSION:Palmitic acid inhibits the proliferation of INS-1 cells via up-regulating the expression of Fzd-2 and Ror-2, as well as promoting Wnt5a to recruit these receptors.