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Massud I, Nishiura K, Ruone S, Holder A, Dinh C, Lipscomb J, Mitchell J, Khalil GM, Heneine W, Garcίa-Lerma JG, Dobard CW. Weekly Oral Tenofovir Alafenamide Protects Macaques from Vaginal and Rectal Simian HIV Infection. Pharmaceutics 2024; 16:384. [PMID: 38543278 PMCID: PMC10974356 DOI: 10.3390/pharmaceutics16030384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/26/2024] [Accepted: 03/07/2024] [Indexed: 04/04/2024] Open
Abstract
Pre-exposure prophylaxis (PrEP) with a weekly oral regimen of antiretroviral drugs could be a suitable preventative option for individuals who struggle with daily PrEP or prefer not to use long-acting injectables. We assessed in macaques the efficacy of weekly oral tenofovir alafenamide (TAF) at doses of 13.7 or 27.4 mg/kg. Macaques received weekly oral TAF for six weeks and were exposed twice-weekly to SHIV vaginally or rectally on day 3 and 6 after each dose. Median TFV-DP levels in PBMCs following the 13.7 mg/kg dose were 3110 and 1137 fmols/106 cells on day 3 and 6, respectively. With the 27.4 mg/kg dose, TFV-DP levels were increased (~2-fold) on day 3 and 6 (6095 and 3290 fmols/106 cells, respectively). Both TAF doses (13.7 and 27.4 mg/kg) conferred high efficacy (94.1% and 93.9%, respectively) against vaginal SHIV infection. Efficacy of the 27.4 mg/kg dose against rectal SHIV infection was 80.7%. We estimate that macaque doses of 13.7 and 27.4 mg/kg are equivalent to approximately 230 and 450 mg of TAF in humans, respectively. Our findings demonstrate the effectiveness of a weekly oral PrEP regimen and suggest that a clinically achievable oral TAF dose could be a promising option for non-daily PrEP.
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Affiliation(s)
- Ivana Massud
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
| | - Kenji Nishiura
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
| | - Susan Ruone
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
| | - Angela Holder
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
| | - Chuong Dinh
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
| | - Jonathan Lipscomb
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
| | - James Mitchell
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
| | - George M. Khalil
- Quantitative Sciences and Data Management Branch, Division of HIV Prevention, National Center for HIV, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA;
| | - Walid Heneine
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
| | - J. Gerardo Garcίa-Lerma
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
| | - Charles W. Dobard
- Laboratory Branch, Division of HIV Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA; (I.M.); (K.N.); (S.R.); (A.H.); (C.D.); (J.L.); (J.M.); (W.H.); (J.G.G.-L.)
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Massud I, Ruone S, Zlotorzynska M, Haaland R, Mills P, Cong ME, Kelley K, Johnson R, Holder A, Dinh C, Khalil G, Pan Y, Kelley CF, Sanchez T, Heneine W, García-Lerma JG. Corrigendum to - "Single oral dose for HIV pre or post-exposure prophylaxis: user desirability and biological efficacy in macaques" [eBioMedicine 58(2020) 102894]. EBioMedicine 2024; 101:105014. [PMID: 38354533 PMCID: PMC10875212 DOI: 10.1016/j.ebiom.2024.105014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Affiliation(s)
- Ivana Massud
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Susan Ruone
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Maria Zlotorzynska
- Rollins School of Public Health, Emory University, Atlanta, GA, United States
| | - Richard Haaland
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Patrick Mills
- Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Disease, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Mian-Er Cong
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Kristen Kelley
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Ryan Johnson
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Angela Holder
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Chuong Dinh
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - George Khalil
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Yi Pan
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Colleen F Kelley
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Travis Sanchez
- Rollins School of Public Health, Emory University, Atlanta, GA, United States
| | - Walid Heneine
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - J Gerardo García-Lerma
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
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Massud I, Krovi A, Nishiura K, Ruone S, Li L, Holder A, Gary J, Mills P, Mitchell J, Khalil G, Pan Y, Luecke E, Gatto G, Heneine W, García-Lerma JG, Johnson L, van der Straten A, Dobard C. Safety and efficacy of a biodegradable implant releasing tenofovir alafenamide for vaginal protection in a macaque model. J Antimicrob Chemother 2022; 77:2964-2971. [PMID: 35913838 DOI: 10.1093/jac/dkac252] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 06/24/2022] [Indexed: 01/16/2023] Open
Abstract
OBJECTIVES To advance the initiative of ending the global epidemic, long-lasting HIV protection is needed through sustained release of antiretroviral drugs for months to years. We investigated in macaques the safety and efficacy of biodegradable polycaprolactone implants releasing tenofovir alafenamide for HIV pre-exposure prophylaxis (PrEP). METHODS Implants were administered subcutaneously in the arm using a contraceptive trocar. Efficacy against vaginal simian-HIV (SHIV) infection was investigated in six pigtailed macaques that received two tenofovir alafenamide implants (0.35 mg/day), one in each arm, for a total release rate of tenofovir alafenamide at 0.7 mg/day. Macaques were exposed to SHIV twice weekly for 6 weeks. Statistical analyses were used to compare outcome with eight untreated controls. Histological assessments were performed on skin biopsies collected near implantation sites. RESULTS Median (range) tenofovir diphosphate level in PBMCs was 1519 (1068-1898) fmol/106 cells. All macaques with tenofovir alafenamide implants were protected against vaginal SHIV infection. In contrast, 7/8 controls were infected after a median of 4 SHIV exposures (P = 0.0047). Histological assessment of tissues near tenofovir alafenamide implant sites showed inflammation and necrosis in 5/6 animals, which were not evident by visual inspection. CONCLUSIONS We demonstrated complete protection against vaginal SHIV infection with two implants releasing a total of 0.7 mg of tenofovir alafenamide per day. We also identified tenofovir diphosphate concentrations in PBMCs associated with complete vaginal protection. Consistent with previous findings, we observed adverse local toxicity and necrosis near the tenofovir alafenamide implant site. Improved tenofovir alafenamide implants that are safe and maintain high efficacy have the potential to provide long-lasting protection against vaginal HIV infection.
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Affiliation(s)
- I Massud
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - A Krovi
- RTI International, Research Triangle Park, NC, USA
| | - K Nishiura
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - S Ruone
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - L Li
- RTI International, Research Triangle Park, NC, USA
| | - A Holder
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - J Gary
- Infectious Diseases Pathology Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infection Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - P Mills
- Comparative Medicine Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infection Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - J Mitchell
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - G Khalil
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Y Pan
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - E Luecke
- RTI International, Research Triangle Park, NC, USA
| | - G Gatto
- RTI International, Research Triangle Park, NC, USA
| | - W Heneine
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - J G García-Lerma
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - L Johnson
- RTI International, Research Triangle Park, NC, USA
| | - A van der Straten
- Center for AIDS Prevention Studies (CAPS), Department of Medicine, University of California San Francisco, San Francisco, CA and ASTRA Consulting, Kensington, CA, USA
| | - C Dobard
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Massud I, Ruone S, Zlotorzynska M, Haaland R, Mills P, Cong ME, Kelley K, Johnson R, Holder A, Dinh C, Khalil G, Pan Y, Kelley CF, Sanchez T, Heneine W, García-Lerma JG. Single oral dose for HIV pre or post-exposure prophylaxis: user desirability and biological efficacy in macaques. EBioMedicine 2020; 58:102894. [PMID: 32707451 PMCID: PMC7381488 DOI: 10.1016/j.ebiom.2020.102894] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/09/2020] [Accepted: 06/29/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Daily oral pre- or post-exposure prophylaxis (PrEP or PEP) is highly effective in preventing HIV infection. However, many people find it challenging to adhere to a daily oral regimen. Chemoprophylaxis with single oral doses of antiretroviral drugs taken before or after sex may better adapt to changing or unanticipated sexual practices and be a desirable alternative to daily PrEP or PEP. We investigated willingness to use a single oral pill before or after sex among men who have sex with men (MSM) and assessed the biological efficacy of a potent antiretroviral combination containing elvitegravir (EVG), emtricitabine (FTC), and tenofovir alafenamide (TAF). METHODS Data on willingness to use single-dose PrEP or PEP were obtained from the 2017 cycle of the American Men's Internet Survey (AMIS), an annual online behavioral surveillance survey of MSM in the United States. Antiretroviral drug levels were measured in humans and macaques to define drug distribution in rectal tissue and identify clinically relevant doses for macaque modeling studies. The biological efficacy of a single dose of FTC/TAF/EVG as PrEP or PEP was investigated using a repeat-challenge macaque model of rectal HIV infection. FINDINGS Through pharmacokinetic assessment in humans and macaques we found that EVG penetrates and concentrates in rectal tissues supporting its addition to FTC/TAF to boost and extend chemoprophylactic activity. Efficacy estimates for a single oral dose given to macaques 4h before or 2h after SHIV exposure was 91•7%[35•7%-98•9%] and 100%, respectively, compared to 80•1%[13•9%-95•4%] and 64•6%[-19•4%-89•5%] when single doses were given 6 and 24h post challenge, respectively. A two-dose regimen at 24h and 48h after exposure was also protective [77•1%[1•7%-94•7%]. INTERPRETATION Informed by user willingness, human and macaque pharmacokinetic data, and preclinical efficacy we show that single-dose prophylaxis before or after sex is a promising HIV prevention strategy. Carefully designed clinical trials are needed to determine if any of these strategies will be effective in humans. FUNDING Funded by CDC intramural funds, CDC contract HCVJCG2-2016-03948 (to CFK), and a grant from the MAC AIDS Fund and by the National Institutes of Health [P30AI050409] - the Emory Center for AIDS Research (to MZ and TS).
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Affiliation(s)
- Ivana Massud
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - Susan Ruone
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - Maria Zlotorzynska
- Rollins School of Public Health, Emory University, Atlanta, GA, United States
| | - Richard Haaland
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - Patrick Mills
- Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Disease, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Mian-Er Cong
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - Kristen Kelley
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - Ryan Johnson
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - Angela Holder
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - Chuong Dinh
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - George Khalil
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - Yi Pan
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - Colleen F Kelley
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Travis Sanchez
- Rollins School of Public Health, Emory University, Atlanta, GA, United States
| | - Walid Heneine
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States
| | - J Gerardo García-Lerma
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, United States.
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Massud I, Cong ME, Ruone S, Holder A, Dinh C, Nishiura K, Khalil G, Pan Y, Lipscomb J, Johnson R, Deyounks F, Rooney JF, Babusis D, Park Y, McCallister S, Callebaut C, Heneine W, García-Lerma JG. Efficacy of Oral Tenofovir Alafenamide/Emtricitabine Combination or Single-Agent Tenofovir Alafenamide Against Vaginal Simian Human Immunodeficiency Virus Infection in Macaques. J Infect Dis 2020; 220:1826-1833. [PMID: 31362305 DOI: 10.1093/infdis/jiz383] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 07/18/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Tenofovir alafenamide (TAF)-based regimens are being evaluated for pre-exposure prophylaxis (PrEP). We used a macaque model of repeated exposures to simian human immunodeficiency virus (SHIV) to investigate whether TAF alone or the combination of TAF and emtricitabine (FTC) can prevent vaginal infection. METHODS Pigtail macaques were exposed vaginally to SHIV162p3 once a week for up to 15 weeks. Animals received clinical doses of FTC/TAF (n = 6) or TAF (n = 9) orally 24 hours before and 2 hours after each weekly virus exposure. Infection was compared with 21 untreated controls. RESULTS Five of the 6 animals in the FTC/TAF and 4 of the 9 animals in the TAF alone group were protected against infection (P = .001 and P = .049, respectively). The calculated efficacy of FTC/TAF and TAF was 91% (95% confidence interval [CI], 34.9%-98.8%) and 57.8% (95% CI, -8.7% to 83.6%), respectively. Infection in FTC/TAF but not TAF-treated macaques was delayed relative to controls (P = .005 and P = .114). Median tenofovir diphosphate (TFV-DP) levels in peripheral blood mononuclear cells (PBMCs) were similar among infected and uninfected macaques receiving TAF PrEP (351 and 143 fmols/106 cells, respectively; P = .921). CONCLUSIONS Emtricitabine/TAF provided a level of protection against vaginal challenge similar to FTC/TFV disoproxil fumarate combination in the macaque model. Our results support the clinical evaluation of FTC/TAF for PrEP in women.
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Affiliation(s)
- Ivana Massud
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Mian-Er Cong
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Susan Ruone
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Angela Holder
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Chuong Dinh
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Kenji Nishiura
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - George Khalil
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Yi Pan
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jonathan Lipscomb
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Ryan Johnson
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Frank Deyounks
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | | | - Yeojin Park
- Gilead Sciences, Inc., Foster City, California
| | | | | | - Walid Heneine
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - J Gerardo García-Lerma
- Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
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Council OD, Ruone S, Mock PA, Khalil G, Martin A, Curlin ME, McNicholl JM, Heneine W, Leelawiwat W, Choopanya K, Vanichseni S, Cherdtrakulkiat T, Anekvorapong R, Martin M, García-Lerma JG. HIV-1 genetic diversity to estimate time of infection and infer adherence to preexposure prophylaxis. AIDS 2019; 33:2299-2307. [PMID: 31764095 PMCID: PMC11000142 DOI: 10.1097/qad.0000000000002390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To estimate time of HIV infection in participants from the Bangkok Tenofovir Study (BTS) with daily oral tenofovir disoproxil fumarate (TDF) for preexposure prophylaxis (PrEP) and relate infection with adherence patterns. DESIGN We used the diversity structure of the virus population at the first HIV RNA-positive sample to estimate the date of infection, and mapped these estimates to medication diaries obtained under daily directly observed therapy (DOT). METHODS HIV genetic diversity was investigated in all 17 PrEP breakthrough infections and in 16 placebo recipients. We generated 10-25 HIV env sequences from each participant by single genome amplification, and calculated time since infection (and 95% confidence interval) using Poisson models of early virus evolution. Study medication diaries obtained under daily DOT were then used to compute the number of missed TDF doses at the approximate date of infection. RESULTS Fifteen of the 17 PrEP breakthrough infections were successfully amplified. Of these, 13 were initiated by a single genetic variant and generated reliable estimates of time since infection (median = 47 [IQR = 35] days). Eleven of these 13 were under daily DOT at the estimated time of infection. Analysis of medication diaries in these 11 participants showed 100% adherence in five, 90-95% adherence in two, 55% adherence in one, and nonadherence in three. CONCLUSION We estimated time of infection in participants from BTS and found several infections when high levels of adherence to TDF were reported. Our results suggest that the biological efficacy of daily TDF against parenteral HIV exposure is not 100%.
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Affiliation(s)
- Olivia D Council
- aLaboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, US Centers for Disease Control and Prevention, Atlanta, Georgia, USA bThailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand cQuantitative Sciences and Data Management Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia dDepartment of Medicine, Division of Infectious Diseases, Oregon Health and Sciences University, Portland, Oregon, USA eBangkok Tenofovir Study Group, Bangkok, Thailand
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Daly MB, Clayton AM, Ruone S, Mitchell J, Dinh C, Holder A, Jolly J, García-Lerma JG, Weed JL. Training rhesus macaques to take daily oral antiretroviral therapy for preclinical evaluation of HIV prevention and treatment strategies. PLoS One 2019; 14:e0225146. [PMID: 31730629 PMCID: PMC6857902 DOI: 10.1371/journal.pone.0225146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/29/2019] [Indexed: 11/18/2022] Open
Abstract
Background Macaque models of simian or simian/human immunodeficiency virus (SIV or SHIV) infection are critical for the evaluation of antiretroviral (ARV)-based HIV treatment and prevention strategies. However, modelling human oral ARV administration is logistically challenging and fraught by limited adherence. Here, we developed a protocol for administering daily oral doses of ARVs to macaques with a high rate of compliance. Methods Parameters of positive reinforcement training (PRT), behavioral responses and optimal drug delivery foods were defined in 7 male rhesus macaques (Macaca mulatta). Animals were trained to sit in a specified cage location prior to receiving ARVs, emtricitabine (FTC) and tenofovir alafenamide (TAF), in a blended food mixture, which was followed immediately with a juice chaser. Consistency of daily oral adherence was evaluated in 4 trained macaques receiving clinically equivalent doses of FTC and TAF (20 and 1.5 mg/kg, respectively) in a short-term (1 month) and an extended (6 month) trial. Adherence was monitored using medication diaries and by quantifying intracellular FTC-triphosphate (FTC-TP) and tenofovir-diphosphate (TFV-DP) concentrations in peripheral mononuclear blood cells (PBMCs). Results Trained macaques quickly and consistently took daily oral ARVs for 1 month with an average 99.8% observed adherence. Intracellular concentrations of TFV-DP (median = 845.8 fmol/million cells [range, 620.8–1031.3]) and FTC-TP (median = 367.0 fmol/million cells [range, 289.5–413.5) in PBMCs were consistent with high adherence. Extended treatment with select subjects yielded similar observations for three months (99.5% adherence, 352/356 complete doses taken), although a sudden drop in adherence was observed after splenic biopsy surgery. Conclusions We demonstrate that trained macaques reliably adhere to a daily oral ARV regimen, although unexpected adherence issues are possible. Our approach, using clinical doses of oral FTC and TAF daily, further refines macaque models of HIV treatment and prevention by mimicking the human route and timing of ARV administration.
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Affiliation(s)
- Michele B. Daly
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - April M. Clayton
- Comparative Medicine Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Susan Ruone
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - James Mitchell
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Chuong Dinh
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Angela Holder
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Julian Jolly
- Comparative Medicine Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - J. Gerardo García-Lerma
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail: (JGGL); (JLW)
| | - James L. Weed
- Comparative Medicine Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail: (JGGL); (JLW)
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Radzio-Basu J, Council O, Cong ME, Ruone S, Newton A, Wei X, Mitchell J, Ellis S, Petropoulos CJ, Huang W, Spreen W, Heneine W, García-Lerma JG. Drug resistance emergence in macaques administered cabotegravir long-acting for pre-exposure prophylaxis during acute SHIV infection. Nat Commun 2019; 10:2005. [PMID: 31043606 PMCID: PMC6494879 DOI: 10.1038/s41467-019-10047-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 02/19/2019] [Indexed: 12/17/2022] Open
Abstract
A long-acting injectable formulation of the HIV integrase inhibitor cabotegravir (CAB-LA) is currently in clinical development for PrEP. Although the long plasma half-life of CAB-LA is an important attribute for PrEP, it also raises concerns about drug resistance emergence if someone becomes infected with HIV, or if PrEP is initiated during undiagnosed acute infection. Here we use a macaque model of SHIV infection to model risks of drug resistance to CAB-LA PrEP. Six macaques infected with SHIV received CAB-LA before seroconversion. We show integrase mutations G118R, E92G/Q, or G140R in plasma from 3/6 macaques as early as day 57, and identify G118R and E92Q in viruses from vaginal and rectal fluids. G118R and G140R confer > 800-fold resistance to CAB and cross-resistance to all licensed integrase inhibitors. Our results emphasize the need for appropriate HIV testing strategies before and possibly shortly after initiating CAB LA PrEP to exclude acute infection. Long-acting formulation of the integrase inhibitor cabotegravir (CAB LA) is in clinical development for HIV pre-exposure prophylaxis (PrEP). Here, using a SHIV macaque model, the authors show emergence of integrase mutations associated to CAB LA PrEP that confer pan-integrase inhibitor resistance.
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Affiliation(s)
- Jessica Radzio-Basu
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Olivia Council
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Mian-Er Cong
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Susan Ruone
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Alicia Newton
- Monogram Biosciences, 345 Oyster Point Blvd, San Francisco, CA, 94080, USA
| | - Xierong Wei
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - James Mitchell
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Shanon Ellis
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | | | - Wei Huang
- Monogram Biosciences, 345 Oyster Point Blvd, San Francisco, CA, 94080, USA
| | | | - Walid Heneine
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - J Gerardo García-Lerma
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA.
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9
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Zheng Q, Ruone S, Switzer WM, Heneine W, García-Lerma JG. Limited SHIV env diversification in macaques failing oral antiretroviral pre-exposure prophylaxis. Retrovirology 2012; 9:40. [PMID: 22571771 PMCID: PMC3464968 DOI: 10.1186/1742-4690-9-40] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 05/09/2012] [Indexed: 11/10/2022] Open
Abstract
Background Pre-exposure prophylaxis (PrEP) with daily Truvada [a combination of emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF)] is a novel HIV prevention strategy recently found to prevent HIV transmission among men who have sex with men and heterosexual couples. Acute infection in adherent persons who fail PrEP will inevitably occur under concurrent antiretroviral therapy, thus raising questions regarding the potential impact of PrEP on early viral dynamics. We investigated viral evolution dynamics in a macaque model of PrEP consisting of repeated rectal exposures to SHIV162P3 in the presence of PrEP. Results Four macaques were infected during daily or intermittent PrEP with FTC or FTC/TDF, and five were untreated controls. SHIV env sequence evolution was monitored by single genome amplification with phylogenetic and sequence analysis. Mean nucleotide divergence from transmitted founder viruses calculated 17 weeks (range = 12–20) post peak viremia was significantly lower in PrEP failures than in control animals (7.2 × 10-3 compared to 1.6 × 10-2 nucleotide substitutions per site per year, respectively, p < 0.0001). Mean virus diversity was also lower in PrEP failures after 17 weeks (0.13% vs. 0.53% in controls, p < 0.0001). Conclusions Our results in a macaque model of acute HIV infection suggest that infection during PrEP limits early virus evolution likely because of a direct antiviral effect of PrEP and/or reduced target cell availability. Reduced virus diversification during early infection might enhance immune control by slowing the selection of escape mutants.
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Affiliation(s)
- Qi Zheng
- National Center for HIV, Hepatitis, STD, and Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
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10
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Tong S, Singh J, Ruone S, Humphrey C, Yip CCY, Lau SKP, Anderson LJ, Kaur T. Identification of adenoviruses in fecal specimens from wild chimpanzees (Pan trogylodytes schweinfurthii) in western Tanzania. Am J Trop Med Hyg 2010; 82:967-70. [PMID: 20439983 DOI: 10.4269/ajtmh.2010.09-0668] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
DNA of two distinctive adenoviruses was detected in wild chimpanzees in western Tanzania that showed clinical signs of acute, upper respiratory disease, notably coughing. The amplified sequences from part of the capsid hexon gene suggests that one virus is a novel adenovirus serotype candidate and the other virus is a species C adenovirus most closely related to recent isolates from captive chimpanzees in the United States, Simian AdV 37 with 86% nucleic acid identity and Simian AdV 40 with 95% nucleic acid identity, respectively. The species C adenovirus sequences suggest possible recombination with a human adenovirus. The source of these viruses and disease association is not known.
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Affiliation(s)
- Suxiang Tong
- Gastroenteritis and Respiratory Viruses Laboratory Branch, Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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11
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Schatzberg SJ, Li Q, Porter BF, Barber RM, Claiborne MK, Levine JM, Levine GJ, Israel SK, Young BD, Kiupel M, Greene C, Ruone S, Anderson L, Tong S. Broadly reactive pan-paramyxovirus reverse transcription polymerase chain reaction and sequence analysis for the detection of Canine distemper virus in a case of canine meningoencephalitis of unknown etiology. J Vet Diagn Invest 2010; 21:844-9. [PMID: 19901287 DOI: 10.1177/104063870902100613] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Despite the immunologic protection associated with routine vaccination protocols, Canine distemper virus (CDV) remains an important pathogen of dogs. Antemortem diagnosis of systemic CDV infection may be made by reverse transcription polymerase chain reaction (RT-PCR) and/or immunohistochemical testing for CDV antigen; central nervous system infection often requires postmortem confirmation via histopathology and immunohistochemistry. An 8-month-old intact male French Bulldog previously vaccinated for CDV presented with multifocal neurologic signs. Based on clinical and postmortem findings, the dog's disease was categorized as a meningoencephalitis of unknown etiology. Broadly reactive, pan-paramyxovirus RT-PCR using consensus-degenerate hybrid oligonucleotide primers, combined with sequence analysis, identified CDV amplicons in the dog's brain. Immunohistochemistry confirmed the presence of CDV antigens, and a specific CDV RT-PCR based on the phosphoprotein gene identified a wild-type versus vaccinal virus strain. This case illustrates the utility of broadly reactive PCR and sequence analysis for the identification of pathogens in diseases with unknown etiology.
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Affiliation(s)
- Scott J Schatzberg
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
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12
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Tong S, Conrardy C, Ruone S, Kuzmin IV, Guo X, Tao Y, Niezgoda M, Haynes L, Agwanda B, Breiman RF, Anderson LJ, Rupprecht CE. Detection of novel SARS-like and other coronaviruses in bats from Kenya. Emerg Infect Dis 2009; 15:482-5. [PMID: 19239771 PMCID: PMC2681120 DOI: 10.3201/eid1503.081013] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Diverse coronaviruses have been identified in bats from several continents but not from Africa. We identified group 1 and 2 coronaviruses in bats in Kenya, including SARS-related coronaviruses. The sequence diversity suggests that bats are well-established reservoirs for and likely sources of coronaviruses for many species, including humans.
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Affiliation(s)
- Suxiang Tong
- Gastroenteritis and Respiratory Virus Laboratory Branch, Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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13
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Van Dam C, Syed S, Eron J, Ostrander M, Engler R, Damon I, Montgomery J, Tong S, Adimora A, Kahn K, Ruone S, Anderson L, Weber D. Severe Postvaccinia Encephalitis with Acute Disseminated Encephalomyelitis: Recovery with Early Intravenous Immunoglobulin, High‐Dose Steroids, and Vaccinia Immunoglobulin. Clin Infect Dis 2009; 48:e47-9. [DOI: 10.1086/596553] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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14
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Rhoades AR, Ruone S, Formosa T. Structural features of nucleosomes reorganized by yeast FACT and its HMG box component, Nhp6. Mol Cell Biol 2004; 24:3907-17. [PMID: 15082784 PMCID: PMC387760 DOI: 10.1128/mcb.24.9.3907-3917.2004] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Revised: 11/26/2003] [Accepted: 02/08/2004] [Indexed: 11/20/2022] Open
Abstract
The Saccharomyces cerevisiae Spt16/Cdc68, Pob3, and Nhp6 proteins (SPN or yFACT) bind to and alter nucleosomes in vitro, providing a potential explanation for their importance in both transcription and replication in vivo. We show that nucleosomes bound by either Nhp6 alone or the yFACT complex remain largely intact and immobile but are significantly reorganized, as indicated by changes in the pattern of sensitivity to DNase I and enhanced digestion by some restriction endonucleases. In contrast, yFACT enhanced access to exonuclease III only at very high levels of enzyme, suggesting that the DNA near the entry and exit sites of nucleosomes is largely unperturbed and that the position of the histone octamers relative to the DNA is not altered during reorganization. DNase I sensitivity was enhanced at sites clustered near the center of the nucleosomal DNA, away from the entry and exit points, and the pattern of nuclease sensitivity was only mildly affected by the configuration of linker extensions, further indicating that linkers play only a minor role in the reorganization of nucleosomes by yFACT. The DNA in contact with H2A-H2B dimers is therefore the region whose nuclease sensitivity was the least affected by yFACT reorganization. The most dramatic changes in nucleosome structure occurred when Spt16-Pob3 and the HMG box protein Nhp6 were both present, but Nhp6 alone altered DNase I sensitivity at some specific sites, supporting an independent role for this class of proteins in the general management of chromatin properties. yFACT activity does not require ATP hydrolysis and does not alter the position of nucleosomes, indicating that it acts through a mechanism distinct from chromatin remodeling. The results presented here suggest instead that yFACT promotes polymerase progression by reorganizing nucleosome cores into a less inhibitory conformation in which the properties of DNA sequences near the center of the nucleosomes are altered.
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Affiliation(s)
- Alison R Rhoades
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA
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15
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Ruone S, Rhoades AR, Formosa T. Multiple Nhp6 molecules are required to recruit Spt16-Pob3 to form yFACT complexes and to reorganize nucleosomes. J Biol Chem 2003; 278:45288-95. [PMID: 12952948 DOI: 10.1074/jbc.m307291200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Saccharomyces cerevisiae Nhp6 protein contains a DNA-binding motif that is similar to those found in the high mobility group B family of chromatin proteins. Nhp6 bound to nucleosomes and made at least two changes in them: the nucleosomal DNA became more sensitive to DNase I at specific sites, and the nucleosomes became competent to bind Spt16-Pob3 to form yFACT.nucleosome complexes. Both changes occurred at similar concentrations of Nhp6, suggesting that they reflect the same structural reorganization of the nucleosome. Nucleosomes have multiple binding sites for Nhp6, and structural reorganization was associated with a concentration of Nhp6 about 10-fold higher than that needed for simple binding. We propose that the coordinated action of multiple Nhp6 molecules is required to convert nucleosomes to an alternative form as the first step in a two-step reorganization of nucleosomes with the second step being dependent on Spt16-Pob3. The presence of linker DNA had only subtle effects on these processes, indicating that both Nhp6 and yFACT act on core nucleosome structure rather than on the interaction between nucleosomes and adjacent DNA. These results suggest that Nhp6 and the related high mobility group B proteins may have a general role in promoting rearrangements of chromatin by initiating the destabilization of core nucleosomal structure.
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Affiliation(s)
- Susan Ruone
- University of Utah School of Medicine, Department of Biochemistry, Salt Lake City, Utah 84132, USA
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Formosa T, Ruone S, Adams MD, Olsen AE, Eriksson P, Yu Y, Rhoades AR, Kaufman PD, Stillman DJ. Defects in SPT16 or POB3 (yFACT) in Saccharomyces cerevisiae cause dependence on the Hir/Hpc pathway: polymerase passage may degrade chromatin structure. Genetics 2002; 162:1557-71. [PMID: 12524332 PMCID: PMC1462388 DOI: 10.1093/genetics/162.4.1557] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Spt16/Cdc68, Pob3, and Nhp6 collaborate in vitro and in vivo as the yeast factor SPN, which is homologous to human FACT. SPN/FACT complexes mediate passage of polymerases through nucleosomes and are important for both transcription and replication. An spt16 mutation was found to be intolerable when combined with a mutation in any member of the set of functionally related genes HIR1, HIR2/SPT1, HIR3/HPC1, or HPC2. Mutations in POB3, but not in NHP6A/B, also display strong synthetic defects with hir/hpc mutations. A screen for other mutations that cause dependence on HIR/HPC genes revealed genes encoding members of the Paf1 complex, which also promotes transcriptional elongation. The Hir/Hpc proteins affect the expression of histone genes and also promote normal deposition of nucleosomes; either role could explain an interaction with elongation factors. We show that both spt16 and pob3 mutants respond to changes in histone gene numbers, but in opposite ways, suggesting that Spt16 and Pob3 each interact with histones but perhaps with different subsets of these proteins. Supporting this, spt16 and pob3 mutants also display different sensitivities to mutations in the N-terminal tails of histones H3 and H4 and to mutations in enzymes that modulate acetylation of these tails. Our results support a model in which SPN/FACT has two functions: it disrupts nucleosomes to allow polymerases to access DNA, and it reassembles the nucleosomes afterward. Mutations that impair the reassembly activity cause chromatin to accumulate in an abnormally disrupted state, imposing a requirement for a nucleosome reassembly function that we propose is provided by Hir/Hpc proteins.
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Affiliation(s)
- Tim Formosa
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA.
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