HIV-1 Tat protein impairs adipogenesis and induces the expression and secretion of proinflammatory cytokines in human SGBS adipocytes.

BACKGROUND HIV-1 Tat protein has been shown to play multiple roles in the pathogenesis of AIDS; however, there is no information currently available on its effects on adipose tissue alterations. We have studied the effects of Tat on SGBS adipocytes to gain insight on its role on the development of lipodystrophy. METHODS SGBS preadipocytes were exposed to Tat during and after differentiation. Acquisition of adipocyte morphology, expression of gene markers of adipogenesis and inflammation, release of adipokines and cytokines to the medium, and glucose uptake were measured. The action of Tat on tumour necrosis factor (TNF)-α-regulated messenger RNA expression was determined in differentiated adipocytes. The capacity of rosiglitazone, resveratrol and parthenolide to influence the action of Tat was also assessed. RESULTS Tat treatment reduced the number of SGBS preadipocytes that acquired adipocyte morphology. It also led to repression of adipogenic gene expression and induced the coordinate expression and release of proinflammatory cytokines in human adipose cells. Moreover, combined treatment with Tat and TNF-α produced an additive effect on the repression of adipocyte genes. The observed effects of Tat on gene transcription in adipocytes were due, in part, to TNF-α that was secreted as a consequence of intracellular exposure to Tat. CONCLUSIONS Tat impairs adipogenesis in human SGBS preadipocytes and increases the expression and release of proinflammatory cytokines. Positive crosstalk between Tat and TNF-α contributes to the anti-adipogenic and proinflammatory effects. HIV-1 Tat protein may play a role in the adipose tissue alterations that ultimately lead to lipoatrophy and systemic metabolic disturbances observed in HIV-1-infected patients.