Abstract:
Endophytic fungi are promising sources of novel antiviral compounds, and the crude extract PO4PR2 from Alternaria alternata has previously shown anti-HIV-1 activity. This study evaluated its efficacy against integrase strand transfer inhibitor (INSTI)-resistant HIV-1 and its mechanism of action. Key resistance mutations (Y143H, G118R, N155H, and R263K) were introduced into the HIV-1 pNL4.3 clone via site-directed mutagenesis and confirmed by Sanger sequencing. Viral infectivity was assessed in TZM-bl cells, while cytotoxicity was measured using an MTT assay. Antiviral activity was determined through a luciferase-based assay, and integration inhibition was evaluated using integrase activity assays and Alu-gag nested PCR. The extract demonstrated potent inhibition of resistant mutants, with low IC₅₀ values (0.02971–0.1652 μg/mL), and showed minimal cytotoxicity (CC₅₀ = 300 μg/mL), maintaining over 80% cell viability. It inhibited integrase activity by 67%, specifically targeting the strand-transfer step, and significantly reduced integrated viral DNA. Molecular docking of fourteen compounds identified coumarin derivatives as key bioactive metabolites, exhibiting mutation-tolerant binding within the integrase catalytic pocket. Overall, these findings highlight PO4PR2 as a promising source of compounds for developing new therapies targeting drug-resistant HIV-1 integrase.
Keywords: Endophytic fungi; HIV-1 antiviral activity; INSTI drug-resistance mutation; coumarin derivatives; Molecular docking; mutation-tolerant inhibition
Biography:
Dr Nompumelelo Mkhwanazi is an acclaimed South African virologist, academic leader, and clinical researcher renowned for her transformative contributions to HIV pathogenesis, viral reservoir characterisation, and novel functional cure strategies. She holds a dual appointment as a Senior Lecturer within the School of Medicine at the University of KwaZulu-Natal (UKZN) and serves as an influential Faculty Member at the world-renowned HIV Pathogenesis Programme (HPP). Driven by a commitment to expanding equitable healthcare solutions across sub-Saharan Africa, her clinical excellence was formally recognized by the South African Medical Research Council (SAMRC) with the prestigious Bronze Scientific Achievement Award. Her continent-wide leadership was further solidified by her nomination for the Best Research Award at the Africa Health Excellence Awards.
