CCL20 and obesity due to melanocortin 4 receptor deficiency: High levels of insulin-like growth factor 1 (IGF1) and insulin in obesity downregulate Glycogen synthase kinase 3 beta (GSK3B) activity by phosphorylating its serine residue, thereby altering the IL-17 signaling pathway, including upregulation of CXCL1, CCL20, and IL-6 expression.