Apolipoprotein D in Lipid Metabolism and Its Functional Implication in Atherosclerosis and Aging

Perdomo, German; Dong, H. Henry

In addition to its altered expression in the brain, apoD is upregulated in cultured myotubes from patients with type 2 diabetes [28] . Likewise, enhanced apoD expression is detected in muscle biopsies from patients with disuse atrophy, a pathological condition that impacts muscle function and activity of daily living [29] . Interestingly, the induction of apoD mRNA expression is accompanied by a corresponding increase in leptin receptor mRNA in the immobilized muscle of patients with disuse atrophy. Immunohistochemistry colocalizes apoD and leptin receptor in the perinuclear area in the immobilized muscle fibers [29] . These data are consistent with the observation of Liu et al. [30] , who show that apoD and leptin receptor physically interact with each other in the brain. ApoD and leptin receptor expression are coordinately regulated in the hypothalamus in modulating food intake and energy homeostasis in mice. Dissociation of apoD with the leptin receptor is linked to the development of obesity in leptin receptor-deficient db/db mice [30] .