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Naicker D, Sonela N, Jin SW, Mulaudzi T, Ojwach D, Reddy T, Brockman MA, Brumme ZL, Ndung'u T, Mann JK. HIV-1 subtype C Nef-mediated SERINC5 down-regulation significantly contributes to overall Nef activity. Retrovirology 2023; 20:3. [PMID: 37004071 PMCID: PMC10067162 DOI: 10.1186/s12977-023-00618-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
BACKGROUND Nef performs multiple cellular activities that enhance HIV-1 pathogenesis. The role of Nef-mediated down-regulation of the host restriction factor SERINC5 in HIV-1 pathogenesis is not well-defined. We aimed to investigate if SERINC5 down-regulation activity contributes to HIV-1 subtype C disease progression, to assess the relative contribution of this activity to overall Nef function, and to identify amino acids required for optimal activity. We measured the SERINC5 down-regulation activity of 106 subtype C Nef clones, isolated from individuals in early infection, for which the Nef activities of CD4 and HLA-I down-regulation as well as alteration of TCR signalling were previously measured. The relationship between SERINC5 down-regulation and markers of disease progression, and the relative contribution of SERINC5 down-regulation to a Nef fitness model-derived E value (a proxy for overall Nef fitness in vivo), were assessed. RESULTS No overall relationship was found between SERINC5 down-regulation and viral load set point (p = 0.28) or rate of CD4+ T cell decline (p = 0.45). CD4 down-regulation (p = 0.02) and SERINC5 down-regulation (p = 0.003) were significant determinants of E values in univariate analyses, with the greatest relative contribution for SERINC5 down-regulation, and only SERINC5 down-regulation remained significant in the multivariate analysis (p = 0.003). Using a codon-by-codon analysis, several amino acids were significantly associated with increased (10I, 11V, 38D, 51T, 65D, 101V, 188H and, 191H) or decreased (10K, 38E, 65E, 135F, 173T, 176T and, 191R) SERINC5 down-regulation activity. Site-directed mutagenesis experiments of selected mutants confirmed a substantial reduction in SERINC5 down-regulation activity associated with the mutation 173T, while mutations 10K, 135F, and 176T were associated with more modest reductions in activity that were not statistically significant. CONCLUSIONS These results suggest that SERINC5 down-regulation is a significant contributor to overall Nef function and identify potential genetic determinants of this Nef function that may have relevance for vaccines or therapeutics.
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Affiliation(s)
- Delon Naicker
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, 4001, South Africa
| | - Nelson Sonela
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, 4001, South Africa
- Chantal BIYA International Reference Centre for Research on HIV/AIDS Prevention and Management (CIRCB), P.O. Box 3077, Yaoundé, Cameroon
| | - Steven W Jin
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
| | - Takalani Mulaudzi
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, 4001, South Africa
| | - Doty Ojwach
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, 4001, South Africa
| | - Tarylee Reddy
- Medical Research Council, Biostatistics Unit, Durban, 4001, South Africa
| | - Mark A Brockman
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, V6Z 1Y6, Canada
| | - Zabrina L Brumme
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, V6Z 1Y6, Canada
| | - Thumbi Ndung'u
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, 4001, South Africa
- Africa Health Research Institute, Durban, 4001, South Africa
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA, USA
- Division of Infection and Immunity, University College London, London, WC1E 6BT, UK
| | - Jaclyn K Mann
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, 4001, South Africa.
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