LEP and obesity due to melanocortin 4 receptor deficiency: It was recently discovered that MAT also expresses leptin.294 Rosiglitazone treatment can promote browning of adipose tissue in bone marrow and increase leptin expression.295 An in vitro study illustrated that the gene expression of leptin could be significantly inhibited by proinflammatory cytokines, hematopoietic cytokines, IL-1β, IL-6, TNF-α, and IFN-γ in human bone marrow adipocytes.296,297 Therefore, in the state of systemic inflammation, such as obesity, inflammatory factors can affect the endocrine function of MAT, leading to further deterioration of the inflammatory response.