Effect of HIV-1 strains and gp120 on PPARγ transcription factor activity and mRNA expression in MSCs differentiated to adipogenesis. In A and C, MSCs were challenged with HIV-1 strains (5 ng/ml) and gp120 (1 μg/ml) in the presence or absence of anti-gp120 pAb, anti p24 pAb and p5p. MSCs were harvested at day 7 and nuclear extracts were processed for PPARγ activity using TransAM PPARγ kit. The PPARγ activity data were expressed by the ratio (±SD) between samples and the control represented by MSC cell cultures differentiated to adipogenesis. The adipogenesis differentiated cell culture PPARγ activity was set at 1. Three experiments performed in duplicate were carried out. In B and D, quantitative real-time RT-PCR was performed at day 7 to analyze PPARγ mRNA expression in cell cultures treated with the viral strains and viral proteins. The mRNA expression data were expressed by the ratio between samples and the control represented by adipogenesis differentiated cell cultures after 18S ribosomial normalization. The adipogenesis differentiated cell culture mRNA was set at 1. Three experiments performed in duplicate were carried out. Statistical significance was determined using Student's t test with *p < 0.05.