Figure 4 | Experimental & Molecular Medicine

Figure 4

From: Extracellular HIV-1 Tat up-regulates expression of matrix metalloproteinase-9 via a MAPK-NF-κB dependent pathway in human astrocytes

Figure 4

Extracellular HIV-1 Tat protein induces MMP-9 expression via TNF-α production. (A) Cytokine ELISA of the medium from CRT-MG cells treated with HIV-1 Tat. CRT-MG cells were treated with 500 ng/ml of HIV-1 Tat protein for the indicated periods. The culture supernatant was analyzed for the levels of cytokines using a sandwich ELISA with purified cytokines as concentration standard. (B) CRT-MG cells were treated with HIV-1 Tat protein in the presence of neutralizing anti-TNF-α, anti-IL-1β or anti-IL-6 antibodies (5 µg/ml) for 48 h. The culture supernatant was collected and analyzed for MMP-9 expression by ELISA and zymography. Asterisk indicates statistical significance at P < 0.001 compared with cell treated with Tat alone. (C) CRT-MG cells were treated with TNF-α (10 ng/ml) for the indicated periods. The culture supernatant was analyzed for the levels of MMP-9 protein and gelatinolytic activity by ELISA and zymography, respectively.

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