TLR4 and obesity due to melanocortin 4 receptor deficiency: High n-6 PUFA intake has been reported to upregulate TLR4 expression [58], and a high dietary n-3/n-6 PUFA ratio has been shown to ameliorate obesity-associated inflammation and insulin resistance by inhibiting TLR4 activation in rats [58], which also reflects TLR4 upregulation by n-6 PUFA.