STAT3 and obesity due to melanocortin 4 receptor deficiency: Although we did not find any article about the effect of leptin on TLR4 expression in the pancreas, Jiang et al. [51] observed that leptin induces TLR4 expression via the JAK2-STAT3 pathway in obesity-related osteoarthritis, so the leptin effect on TLR4 expression in other organs cannot be excluded.