HIV-induced platelet activation does not involve NF-κB signaling mechanism.

(A) Platelet lysates collected from HIV-negative subjects (HIV-, N = 2) and HIV-positive subjects (HIV+, N = 2) were subjected to electrophoretic mobility shift assays followed by supershift with anti-p50 and anti-RelA antibodies. Incubation with pre-immune serum was included as a control. Both p50 and RelA antibodies altered the mobility of bands, suggesting the presence of these two molecules in NF-κB/DNA complexes, however, no apparent differences were found between HIV- and HIV+ samples. (B) Platelet lysates collected from HIV-negative, healthy subjects (HIV-, N = 11), HIV-positive patients without cocaine use (HIV+Cocaine-, N = 10), and HIV-positive patients with reported cocaine use within one year (HIV+Cocaine+, N = 8) were subjected to immunoblot analysis with antibodies against IKKα, IKKβ, IκBα, or α-Tubulin. Expression levels of IKKα and IKKβ were noted to be similar between the groups. There was an increase in IκBα phosphorylation as evidenced by the appearance of a less mobile, upper band (*), which was confirmed by densitometric analysis of this upper phospho-IκBα band as shown in (C). (D) Platelet lysates collected from HIV- subjects (N = 15), HIV+Coc- (N = 10), and HIV+Coc+ (N = 5) were subjected to immunoprecipitation with an anti-IKKβ antibody followed by an IKKβ in vitro kinase assay. Incorporation of [32P] into the recombinant IκBα substrate was measured by densitometric analysis of autoradiograms. No significant differences in IKKβ activity between the sample groups were noted. Data are represented as fold change in IKKβ activity compared to the HIV- samples and are shown as mean ± SEM.