Differential effects of efavirenz and lopinavir/ritonavir on human adipocyte differentiation, gene expression and release of adipokines and pro-inflammatory cytokines.

In the present study, a comparative assessment of the effects of efavirenz (EFV) and lopinavir/ritonavir (LPV/r; 4:1) on human adipocytes in culture has been performed. Human pre-adipocytes were treated with EFV or LPV/r during or after adipogenic differentiation. Acquisition of adipocyte morphology, expression of gene markers of mitochondrial toxicity, adipogenesis and inflammation, and release of adipokines and cytokines to the medium were measured. Results indicated that EFV and LPV/r impaired adipocyte differentiation in association with a reduction in transcript levels for adipogenic differentiation genes (adiponectin, lipoprotein lipase, leptin) and master regulators of adipogenesis (PPAR, C/EBP). The effects were greater with EFV than LPV/r. Both LPV/r and EFV induced increases in monocytechemoattactant protein-1 (MCP-1) mRNA levels, but the effect was greater with EFV. Similarly, the release of proinflammatory cytokines and other inflammation-related molecules (interleukins 6 and 8, MCP-1, PAI-1) was enhanced to a much higher degree by EFV than by LPV/r. Adiponectin and leptin release by adipocytes was reduced by both drugs, although to a higher extent by EFV. Neither drug affected mitochondrial DNA levels, transcripts encoding mitochondrial proteins or lactate release by adipocytes. In previously differentiated adipocytes, EFV caused a significant reduction in PPARγ and adiponectin expression, whereas LPV/r did not. We conclude that both EFV and LPV/r impair human adipogenesis, reduce adipokine release and increase the expression and release of inflammation-related cytokines, but the overall effects are greater with EFV. These findings may have implications for the pathogenesis of HIV-1-associated lipodystrophy and the development of HIV-1 therapies.