CX3CL1 and obesity due to melanocortin 4 receptor deficiency: Fractalkine has been shown to exert both anti-inflammatory (Zujovic et al., 2000) and proinflammatory properties (Huang et al., 2006; Denes et al., 2008), however, recent studies support the proinflammatory role of fractalkine in obesity-induced hypothalamic inflammation.