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Backiam ADS, Duraisamy S, Karuppaiya P, Balakrishnan S, Sathyan A, Kumarasamy A, Raju A. Analysis of the main bioactive compounds from Ocimum basilicum for their antimicrobial and antioxidant activity. Biotechnol Appl Biochem 2023; 70:2038-2051. [PMID: 37635658 DOI: 10.1002/bab.2508] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 08/14/2023] [Indexed: 08/29/2023]
Abstract
The interest in bioactives especially from botanicals to treat vancomycin-resistant enterococcal (VRE) infections is increased. Many species of Ocimum have a long history in folk medicinal and food industries. Nevertheless, their bioactive compounds remain unexplored. This study is aimed to assess the antimicrobial and antioxidant activity of basil leaf extract prepared using ethanol, methanol, and water. The ethanol and methanol extract have all the phytochemicals (alkaloids, flavonoids, phenolic compounds, tannins, saponins, quinones, carbohydrates, and proteins) except steroids and terpenoids. In addition to steroids and terpenoids, tannin was also absent in the aqueous extract. Total phenolic and flavonoid content was high in ethanol and followed by methanol and aqueous extract. Similarly, ethanol and methanol extract showed strong antimicrobial activity against VRE and MTCC strains at a concentration of 20 mg/mL than aqueous extract. Among the 10 indicators, Staphylococcus aureus is highly susceptible to ethanol extract at a concentration of 8 mg/mL and followed by other MTCC strains. Vancomycin-resistant enterococci pathogens were inhibited at the minimum inhibitory concentration of 14, 16, and 20 mg/mL of ethanol, methanol, and aqueous extract. Further, on the basis of determining the absorbing material (nucleic acid and protein) at 260 nm and scanning electron microscopic, it was confirmed that the loss of cell membrane integrity and cell membrane damage were the effective mechanisms of plant extract antimicrobial activity. All three solvents have shown remarkable antioxidant activity. Gas chromatography-mass spectrometry analysis of basil leaves ethanol extract identified 19 compounds with various therapeutic and food applications.
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Affiliation(s)
- Arockia Doss Susai Backiam
- Department of Microbiology, Vivekanandha College of Arts and Science for Women (Autonomous), Tiruchengode, Tamil Nadu, India
| | - Senbagam Duraisamy
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Chengalpattu, Tamil Nadu, India
| | - Palaniyandi Karuppaiya
- Department of Marine Biotechnology, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Senthilkumar Balakrishnan
- Division of Biological Sciences, Tamil Nadu State Council for Science and Technology, Chennai, Tamil Nadu, India
| | - Aswathy Sathyan
- Department of Marine Biotechnology, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Anbarasu Kumarasamy
- Department of Marine Biotechnology, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Amutha Raju
- Department of Biotechnology, Periyar University Centre for Post Graduate and Research Studies, Dharmapuri, Tamil Nadu, India
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2
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Wang Q, Su S, Xue J, Yu F, Pu J, Bi W, Xia S, Meng Y, Wang C, Yang W, Xu W, Zhu Y, Zheng Q, Qin C, Jiang S, Lu L. An amphipathic peptide targeting the gp41 cytoplasmic tail kills HIV-1 virions and infected cells. Sci Transl Med 2021; 12:12/546/eaaz2254. [PMID: 32493792 DOI: 10.1126/scitranslmed.aaz2254] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 04/28/2020] [Indexed: 12/26/2022]
Abstract
HIV-associated morbidity and mortality have markedly declined because of combinational antiretroviral therapy, but HIV readily mutates to develop drug resistance. Developing antivirals against previously undefined targets is essential to treat existing drug-resistant HIV strains. Some peptides derived from HIV-1 envelope glycoprotein (Env, gp120-gp41) have been shown to be effective in inhibiting HIV-1 infection. Therefore, we screened a peptide library from HIV-1 Env and identified a peptide from the cytoplasmic region, designated F9170, able to effectively inactivate HIV-1 virions and induce necrosis of HIV-1-infected cells, and reactivated latently infected cells. F9170 specifically targeted the conserved cytoplasmic tail of HIV-1 Env and effectively disrupted the integrity of the viral membrane. Short-term monoadministration of F9170 controlled viral loads to below the limit of detection in chronically SHIV-infected macaques. F9170 can enter the brain and lymph nodes, anatomic reservoirs for HIV latency. Therefore, F9170 shows promise as a drug candidate for HIV treatment.
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Affiliation(s)
- Qian Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Shan Su
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Jing Xue
- Key Laboratory of Human Disease Comparative Medicine, Chinese Ministry of Health, Beijing Key Laboratory for Animal Models of Emerging and Re-emerging Infectious Diseases, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing 100021, China
| | - Fei Yu
- College of Life and Science, Hebei Agricultural University, Baoding 071001, China
| | - Jing Pu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Wenwen Bi
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Shuai Xia
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Yu Meng
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Cong Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Wenqian Yang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Wei Xu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Yun Zhu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Qinwen Zheng
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Chuan Qin
- Key Laboratory of Human Disease Comparative Medicine, Chinese Ministry of Health, Beijing Key Laboratory for Animal Models of Emerging and Re-emerging Infectious Diseases, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing 100021, China.
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China. .,Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China.
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Abstract
Paramyxoviruses, including human parainfluenza virus type 3, are internalized into host cells by fusion between viral and target cell membranes. The receptor binding protein, hemagglutinin-neuraminidase (HN), and the fusion protein (F) facilitate viral fusion and entry into cells through a process involving HN activation by receptor binding, which triggers conformational changes in F to activate it to reach its fusion-competent state. Interfering with this process through premature activation of the F protein may be an effective antiviral strategy in vitro. We identified and optimized small compounds that implement this antiviral strategy through an interaction with HN, causing HN to activate F in an untimely fashion. To address that mechanism, we produced novel anti-HPIV3 F conformation-specific antibodies that can be used to assess the functionality of compounds designed to induce F activation. Both the novel antiviral compounds that we present and these newly characterized postfusion antibodies are novel tools for the exploration and development of antiviral approaches. Paramyxoviruses, specifically, the childhood pathogen human parainfluenza virus type 3, are internalized into host cells following fusion between the viral and target cell membranes. The receptor binding protein, hemagglutinin (HA)-neuraminidase (HN), and the fusion protein (F) facilitate viral fusion and entry into the cell through a coordinated process involving HN activation by receptor binding, which triggers conformational changes in the F protein to activate it to reach its fusion-competent state. Interfering with this process through premature activation of the F protein has been shown to be an effective antiviral strategy in vitro. Conformational changes in the F protein leading to adoption of the postfusion form of the protein—prior to receptor engagement of HN at the host cell membrane—render the virus noninfectious. We previously identified a small compound (CSC11) that implements this antiviral strategy through an interaction with HN, causing HN to activate F in an untimely process. To assess the functionality of such compounds, it is necessary to verify that the postfusion state of F has been achieved. As demonstrated by Melero and colleagues, soluble forms of the recombinant postfusion pneumovirus F proteins and of their six helix bundle (6HB) motifs can be used to generate postfusion-specific antibodies. We produced novel anti-HPIV3 F conformation-specific antibodies that can be used to assess the functionality of compounds designed to induce F activation. In this study, using systematic chemical modifications of CSC11, we synthesized a more potent derivative of this compound, CM9. Much like CSC11, CM9 causes premature triggering of the F protein through an interaction with HN prior to receptor engagement, thereby preventing fusion and subsequent infection. In addition to validating the potency of CM9 using plaque reduction, fusion inhibition, and binding avidity assays, we confirmed the transition to a postfusion conformation of F in the presence of CM9 using our novel anti-HPIV3 conformation-specific antibodies. We present both CM9 and these newly characterized postfusion antibodies as novel tools to explore and develop antiviral approaches. In turn, these advances in both our molecular toolset and our understanding of HN-F interaction will support development of more-effective antivirals. Combining the findings described here with our recently described physiologically relevant ex vivo system, we have the potential to inform the development of therapeutics to block viral infection.
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Khoshnevisan K, Maleki H, Samadian H, Shahsavari S, Sarrafzadeh MH, Larijani B, Dorkoosh FA, Haghpanah V, Khorramizadeh MR. Cellulose acetate electrospun nanofibers for drug delivery systems: Applications and recent advances. Carbohydr Polym 2018; 198:131-141. [DOI: 10.1016/j.carbpol.2018.06.072] [Citation(s) in RCA: 137] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/16/2018] [Accepted: 06/14/2018] [Indexed: 01/31/2023]
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5
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Mandal S, Khandalavala K, Pham R, Bruck P, Varghese M, Kochvar A, Monaco A, Prathipati PK, Destache C, Shibata A. Cellulose Acetate Phthalate and Antiretroviral Nanoparticle Fabrications for HIV Pre-Exposure Prophylaxis. Polymers (Basel) 2017; 9. [PMID: 30450244 PMCID: PMC6239201 DOI: 10.3390/polym9090423] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
To adequately reduce new HIV infections, development of highly effective pre-exposure prophylaxis (PrEP) against HIV infection in women is necessary. Cellulose acetate phthalate (CAP) is a pH sensitive polymer with HIV-1 entry inhibitory properties. Dolutegravir (DTG) is an integrase strand transfer inhibitor with potent antiretroviral activity. DTG delivered in combination with CAP may significantly improve current PrEP against HIV. In the present study, the development of DTG-loaded CAP nanoparticles incorporated in thermosensitive (TMS) gel at vaginal pH 4.2 and seminal fluid pH 7.4 is presented as proof-of-concept for improved PrEP. Water–oil–in–water homogenization was used to fabricate DTG-loaded CAP nanoparticles (DTG–CAP–NPs). Size, polydispersity, and morphological analyses illustrate that DTG–CAP–NPs were smooth and spherical, ≤200 nm in size, and monodispersed with a polydispersity index PDI ≤ 0.2. The drug encapsulation (EE%) and release profile of DTG–CAP–NPs was determined by HPLC analysis. The EE% of DTG in DTG–CAP–NPs was evaluated to be ~70%. The thermal sensitivity of the TMS gel was optimized and the pH dependency was evaluated by rheological analysis. DTG release studies in TMS gel revealed that DTG–CAP–NPs were stable in TMS gel at pH 4.2 while DTG–CAP–NPs in TMS gel at pH 7.4 rapidly release DTG (≥80% release within 1 h). Cytotoxicity studies using vaginal cell lines revealed that DTG–CAP–NPs were relatively non-cytotoxic at concentration <1 µg/mL. Confocal microscopic studies illustrate that ≥98% cells retained DTG–CAP–NPs intracellularly over seven days. Antiretroviral drug loaded nanocellulose fabrications in TMS gel delivered intravaginally may enhance both microbicidal and antiretroviral drug efficacy and may present a novel option for female PrEP against HIV.
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Affiliation(s)
- Subhra Mandal
- School of Pharmacy and Health Professions, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; (S.M.); (P.K.P.); (C.D.)
| | - Karl Khandalavala
- Department of Biology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; (K.K.); (R.P.); (M.V.); (A.K.); (A.M.)
| | - Rachel Pham
- Department of Biology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; (K.K.); (R.P.); (M.V.); (A.K.); (A.M.)
| | - Patrick Bruck
- Dana-Farber Cancer Institute, Harvard University, Boston, MA 02215, USA;
| | - Marisa Varghese
- Department of Biology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; (K.K.); (R.P.); (M.V.); (A.K.); (A.M.)
| | - Andrew Kochvar
- Department of Biology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; (K.K.); (R.P.); (M.V.); (A.K.); (A.M.)
| | - Ashley Monaco
- Department of Biology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; (K.K.); (R.P.); (M.V.); (A.K.); (A.M.)
| | - Pavan Kumar Prathipati
- School of Pharmacy and Health Professions, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; (S.M.); (P.K.P.); (C.D.)
| | - Christopher Destache
- School of Pharmacy and Health Professions, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; (S.M.); (P.K.P.); (C.D.)
| | - Annemarie Shibata
- Department of Biology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; (K.K.); (R.P.); (M.V.); (A.K.); (A.M.)
- Correspondence: ; Tel.: +1-402-280-3588
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6
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Hua D, Liu Z, Wang F, Gao B, Chen F, Zhang Q, Xiong R, Han J, Samal SK, De Smedt SC, Huang C. pH responsive polyurethane (core) and cellulose acetate phthalate (shell) electrospun fibers for intravaginal drug delivery. Carbohydr Polym 2016; 151:1240-1244. [DOI: 10.1016/j.carbpol.2016.06.066] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 06/01/2016] [Accepted: 06/15/2016] [Indexed: 02/09/2023]
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7
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Alexandre KB, Mufhandu HT, London GM, Chakauya E, Khati M. Progress and Perspectives on HIV-1 microbicide development. Virology 2016; 497:69-80. [PMID: 27429040 DOI: 10.1016/j.virol.2016.07.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 07/01/2016] [Accepted: 07/04/2016] [Indexed: 12/12/2022]
Abstract
The majority of HIV-1 infections occur via sexual intercourse. Women are the most affected by the epidemic, particularly in developing countries, due to their socio-economic dependence on men and the fact that they are often victims of gender based sexual violence. Despite significant efforts that resulted in the reduction of infection rates in some countries, there is still need for effective prevention methods against the virus. One of these methods for preventing sexual transmission in women is the use of microbicides. In this review we provide a summary of the progress made toward the discovery of affordable and effective HIV-1 microbicides and suggest future directions. We show that there is a wide range of compounds that have been proposed as potential microbicides. Although most of them have so far failed to show protection in humans, there are many promising ones currently in pre-clinical studies and in clinical trials.
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Affiliation(s)
- Kabamba B Alexandre
- Council for Scientific and Industrial Research, Pioneering Health Sciences Laboratory, Biosciences Unit, Pretoria, Gauteng, South Africa.
| | - Hazel T Mufhandu
- Council for Scientific and Industrial Research, Pioneering Health Sciences Laboratory, Biosciences Unit, Pretoria, Gauteng, South Africa
| | - Grace M London
- Department of Health Free State District Health Services and Health Programs, South Africa
| | - E Chakauya
- Council for Scientific and Industrial Research, Pioneering Health Sciences Laboratory, Biosciences Unit, Pretoria, Gauteng, South Africa
| | - M Khati
- Council for Scientific and Industrial Research, Pioneering Health Sciences Laboratory, Biosciences Unit, Pretoria, Gauteng, South Africa; University of Cape Town and Groote Schuur Hospital, Department of Medicine, Cape Town, South Africa
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8
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Date AA, Shibata A, McMullen E, La Bruzzo K, Bruck P, Belshan M, Zhou Y, Destache CJ. Thermosensitive Gel Containing Cellulose Acetate Phthalate-Efavirenz Combination Nanoparticles for Prevention of HIV-1 Infection. J Biomed Nanotechnol 2015; 11:416-27. [PMID: 26307825 DOI: 10.1166/jbn.2015.1942] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The objective of this investigation was to develop and evaluate a nano-microbicide containing a combination of cellulose acetate phthalate (HIV-1 entry inhibitor) and efavirenz (anti-HIV agent) for HIV prophylaxis. Cellulose acetate phthalate-efavirenz combination nanoparticles (CAP-EFV-NPs) were fabricated by the nanoprecipitation method and were characterized for particle size, zeta potential and encapsulation efficiency of efavirenz. CAP-EFV-NPs were incorporated into a thermosensitive gel (CAP-EFV-NP-Gel). CAP-EFV-NPs, CAP-EFV-NP-Gel and efavirenz solution were evaluated for cytotoxicity to HeLa cells and for in vitro short-term (1-day) and long-term (3-day) prophylaxis against HIV-1 infection in TZM-bl cells. CAP-EFV-NPs had size < 100 nm, negative surface charge and encapsulation efficiency of efavirenz was > 98%. CAP-EFV-NPs and CAP-EFV-NP-Gel were significantly less toxic (P < 0.01) to HeLa cells as compared to efavirenz solution. CAP-EFV-NPs showed significantly higher prophylactic activity (P < 0.01) against HIV-1 infection to TZM-bl cells as compared to efavirenz solution and blank CAP nanoparticles. CAP-EFV-NP-Gel can be a promising nano-microbicide for long-term HIV prophylaxis.
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9
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Abstract
Virus-cell fusion is the primary means by which the human immunodeficiency virus-1 (HIV) delivers its genetic material into the human T-cell host. Fusion is mediated in large part by the viral glycoprotein 41 (gp41) which advances through four distinct conformational states: (i) native, (ii) pre-hairpin intermediate, (iii) fusion active (fusogenic), and (iv) post-fusion. The pre-hairpin intermediate is a particularly attractive step for therapeutic intervention given that gp41 N-terminal heptad repeat (NHR) and C-terminal heptad repeat (CHR) domains are transiently exposed prior to the formation of a six-helix bundle required for fusion. Most peptide-based inhibitors, including the FDA-approved drug T20, target the intermediate and there are significant efforts to develop small molecule alternatives. Here, we review current approaches to studying interactions of inhibitors with gp41 with an emphasis on atomic-level computer modeling methods including molecular dynamics, free energy analysis, and docking. Atomistic modeling yields a unique level of structural and energetic detail, complementary to experimental approaches, which will be important for the design of improved next generation anti-HIV drugs.
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10
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Chao L, Lu L, Yang H, Zhu Y, Li Y, Wang Q, Yu X, Jiang S, Chen YH. Identification of a human protein-derived HIV-1 fusion inhibitor targeting the gp41 fusion core structure. PLoS One 2013; 8:e66156. [PMID: 23741527 PMCID: PMC3669275 DOI: 10.1371/journal.pone.0066156] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 05/02/2013] [Indexed: 12/02/2022] Open
Abstract
The HIV-1 envelope glycoprotein (Env) gp41 plays a crucial role in the viral fusion process. The peptides derived from the C-terminal heptad repeat (CHR) of gp41 are potent HIV fusion inhibitors. However, the activity of these anti-HIV-1 peptides in vivo may be attenuated by their induction of anti-gp41 antibodies. Thus, it is essential to identify antiviral peptides or proteins with low, or no, immunogenicity to humans. Here, we found that the C-terminal fragment (aa 462–521) of the human POB1 (the partner of RalBP1), designated C60, is an HIV-1 fusion inhibitor. It bound to N36, the peptide derived from the N-terminal heptad repeat (NHR) of gp41, and to the six-helix bundle (6-HB) formed by N36 and C34, a CHR-peptide, but it did not bind to C34. Unlike the CHR-peptides, C60 did not block gp41 6-HB formation. Rather, results suggest that C60 inhibits HIV-1 fusion by binding to the 6-HB, in particular, the residues in the gp41 NHR domain that are exposed on the surface of 6-HB. Since 6-HB plays a crucial role in the late stage of fusion between the viral envelope and endosomal membrane during the endocytic process of HIV-1, C60 may serve as a host restriction factor to suppress HIV-1 entry into CD4+ T lymphocytes. Taken together, it can be concluded from these results that C60 can be used as a lead for the development of anti-HIV-1 therapeutics or microbicides for the treatment and prevention of HIV-1 infection, as well as a molecular probe to study the fusogenic mechanism of HIV-1.
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Affiliation(s)
- Lijun Chao
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing, P. R. China
| | - Lu Lu
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing, P. R. China
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, P. R. China
| | - Hengwen Yang
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing, P. R. China
| | - Yun Zhu
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing, P. R. China
| | - Yuan Li
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing, P. R. China
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, P. R. China
| | - Qian Wang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, P. R. China
| | - Xiaowen Yu
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing, P. R. China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, P. R. China
- Laboratory of Viral Immunology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
- * E-mail: (SJ); (YC)
| | - Ying-Hua Chen
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing, P. R. China
- * E-mail: (SJ); (YC)
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11
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Konwarh R, Karak N, Misra M. Electrospun cellulose acetate nanofibers: the present status and gamut of biotechnological applications. Biotechnol Adv 2013; 31:421-37. [PMID: 23318668 DOI: 10.1016/j.biotechadv.2013.01.002] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 12/28/2012] [Accepted: 01/04/2013] [Indexed: 11/30/2022]
Abstract
Cellulose acetate (CA) has been a material of choice for spectrum of utilities across different domains ranging from high absorbing diapers to membrane filters. Electrospinning has conferred a whole new perspective to polymeric materials including CA in the context of multifarious applications across myriad of niches. In the present review, we try to bring out the recent trend (focused over last five years' progress) of research on electrospun CA fibers of nanoscale regime in the context of developmental strategies of their blends and nanocomposites for advanced applications. In the realm of biotechnology, electrospun CA fibers have found applications in biomolecule immobilization, tissue engineering, bio-sensing, nutraceutical delivery, bioseparation, crop protection, bioremediation and in the development of anti-counterfeiting and pH sensitive material, photocatalytic self-cleaning textile, temperature-adaptable fabric, and antimicrobial mats, amongst others. The present review discusses these diverse applications of electrospun CA nanofibers.
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Affiliation(s)
- Rocktotpal Konwarh
- Bioproducts Discovery and Development Centre, Department of Plant Agriculture, Crop Science Building, University of Guelph, ON, Canada N1G2W1
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12
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Olaru N, Olaru L, Tudorachi N, Dunca S, Pintilie M. Nanostructures of Cellulose Acetate Phthalate Obtained by Electrospinning from 2-Methoxyethanol-Containing Solvent Systems: Morphological Aspects, Thermal Behavior, and Antimicrobial Activity. Ind Eng Chem Res 2012. [DOI: 10.1021/ie301299d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Niculae Olaru
- “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica-Voda
41 A, Iasi 700487, Romania
| | - Liliana Olaru
- “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica-Voda
41 A, Iasi 700487, Romania
| | - Nita Tudorachi
- “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica-Voda
41 A, Iasi 700487, Romania
| | - Simona Dunca
- “Al. I. Cuza” University, Bd. Carol I 11, Iasi 700506, Romania
| | - Manuela Pintilie
- “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica-Voda
41 A, Iasi 700487, Romania
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13
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Lu L, Pan C, Li Y, Lu H, He W, Jiang S. A bivalent recombinant protein inactivates HIV-1 by targeting the gp41 prehairpin fusion intermediate induced by CD4 D1D2 domains. Retrovirology 2012; 9:104. [PMID: 23217195 PMCID: PMC3531269 DOI: 10.1186/1742-4690-9-104] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 11/11/2012] [Indexed: 02/03/2023] Open
Abstract
Background Most currently approved anti-HIV drugs (e.g., reverse transcriptase inhibitors, protease inhibitors and fusion/entry inhibitors) must act inside or on surface of the target cell to inhibit HIV infection, but none can directly inactivate virions away from cells. Although soluble CD4 (sCD4) can inactivate laboratory-adapted HIV-1 strains, it fails to reduce the viral loads in clinical trials because of its low potency against primary isolates and tendency to enhance HIV-1 infection at low concentration. Thus, it is essential to design a better HIV inactivator with improved potency for developing new anti-HIV therapeutics that can actively attack the virus in the circulation before it attaches to and enter into the target cell. Results We engineered a bivalent HIV-1 inactivator, designated 2DLT, by linking the D1D2 domain of CD4 to T1144, the next generation HIV fusion inhibitor, with a 35-mer linker. The D1D2 domain in this soluble 2DLT protein could bind to the CD4-binding site and induce the formation of the gp41 prehairpin fusion-intermediate (PFI), but showed no sCD4-mediated enhancement of HIV-1 infection. The T1144 domain in 2DLT then bound to the exposed PFI, resulting in rapid inactivation of HIV-1 virions in the absence of the target cell. Beside, 2DLT could also inhibit fusion of the virus with the target cell if the virion escapes the first attack of 2DLT. Conclusion This bivalent molecule can serve as a dual barrier against HIV infection by first inactivating HIV-1 virions away from cells and then blocking HIV-1 entry on the target cell surface, indicating its potential for development as a new class of anti-HIV drug.
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Affiliation(s)
- Lu Lu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College, Institute of Medical Microbiology, Fudan University, Shanghai 200032, China
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14
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Huang C, Soenen SJ, van Gulck E, Vanham G, Rejman J, Van Calenbergh S, Vervaet C, Coenye T, Verstraelen H, Temmerman M, Demeester J, De Smedt SC. Electrospun cellulose acetate phthalate fibers for semen induced anti-HIV vaginal drug delivery. Biomaterials 2012; 33:962-9. [DOI: 10.1016/j.biomaterials.2011.10.004] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 10/01/2011] [Indexed: 11/28/2022]
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15
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Gochin M, Zhou G. Amphipathic properties of HIV-1 gp41 fusion inhibitors. Curr Top Med Chem 2011; 11:3022-32. [PMID: 22044226 PMCID: PMC3219813 DOI: 10.2174/156802611798808488] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 02/26/2011] [Accepted: 12/01/2011] [Indexed: 12/11/2022]
Abstract
Small molecule inhibition of HIV fusion has been an elusive goal, despite years of effort by both pharmaceutical and academic laboratories. In this review, we will discuss the amphipathic properties of both peptide and small molecule inhibitors of gp41-mediated fusion. Many of the peptides and small molecules that have been developed target a large hydrophobic pocket situated within the grooves of the coiled coil, a potential hotspot for inhibiting the trimer of hairpin formation that accompanies fusion. Peptide studies reveal molecular properties required for effective inhibition, including elongated structure and lipophilic or amphiphilic nature. The characteristics of peptides that bind in this pocket provide features that should be considered in small molecule development. Additionally, a novel site for small molecule inhibition of fusion has recently been suggested, involving residues of the loop and fusion peptide. We will review the small molecule structures that have been developed, evidence pointing to their mechanism of action and strategies towards improving their affinity. The data points to the need for a strongly amphiphilic character of the inhibitors, possibly as a means to mediate the membrane - protein interaction that occurs in gp41 in addition to the protein - protein interaction that accompanies the fusion-activating conformational transition.
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Affiliation(s)
- Miriam Gochin
- Department of Basic Sciences, Touro University – California, Vallejo, CA 94592, USA.
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16
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Farzan SF, Palermo LM, Yokoyama CC, Orefice G, Fornabaio M, Sarkar A, Kellogg GE, Greengard O, Porotto M, Moscona A. Premature activation of the paramyxovirus fusion protein before target cell attachment with corruption of the viral fusion machinery. J Biol Chem 2011; 286:37945-37954. [PMID: 21799008 PMCID: PMC3207398 DOI: 10.1074/jbc.m111.256248] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 07/26/2011] [Indexed: 11/06/2022] Open
Abstract
Paramyxoviruses, including the childhood pathogen human parainfluenza virus type 3, enter host cells by fusion of the viral and target cell membranes. This fusion results from the concerted action of its two envelope glycoproteins, the hemagglutinin-neuraminidase (HN) and the fusion protein (F). The receptor-bound HN triggers F to undergo conformational changes that render it competent to mediate fusion of the viral and cellular membranes. We proposed that, if the fusion process could be activated prematurely before the virion reaches the target host cell, infection could be prevented. We identified a small molecule that inhibits paramyxovirus entry into target cells and prevents infection. We show here that this compound works by an interaction with HN that results in F-activation prior to receptor binding. The fusion process is thereby prematurely activated, preventing fusion of the viral membrane with target cells and precluding viral entry. This first evidence that activation of a paramyxovirus F can be specifically induced before the virus contacts its target cell suggests a new strategy with broad implications for the design of antiviral agents.
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Affiliation(s)
- Shohreh F Farzan
- Departments of Pediatrics and of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021
| | - Laura M Palermo
- Departments of Pediatrics and of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021
| | - Christine C Yokoyama
- Departments of Pediatrics and of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021
| | - Gianmarco Orefice
- Departments of Pediatrics and of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021
| | - Micaela Fornabaio
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, 23298-0540
| | - Aurijit Sarkar
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, 23298-0540
| | - Glen E Kellogg
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, 23298-0540
| | - Olga Greengard
- Departments of Pediatrics and of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021; Department of Pediatrics, Mount Sinai School of Medicine, New York, New York 10029
| | - Matteo Porotto
- Departments of Pediatrics and of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021
| | - Anne Moscona
- Departments of Pediatrics and of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021.
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17
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Virucidal activity of the dendrimer microbicide SPL7013 against HIV-1. Antiviral Res 2011; 90:195-9. [PMID: 21459115 DOI: 10.1016/j.antiviral.2011.03.186] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 03/27/2011] [Accepted: 03/28/2011] [Indexed: 11/24/2022]
Abstract
Topical microbicides for use by women to prevent the transmission of human immunodeficiency virus (HIV) and other sexually transmitted infections are urgently required. Dendrimers are highly branched nanoparticles being developed as microbicides. SPL7013 is a dendrimer with broad-spectrum activity against HIV type I (HIV-1) and -2 (HIV-2), herpes simplex viruses type-1 (HSV-1) and -2 (HSV-2) and human papillomavirus. SPL7013 [3% (w/w)] has been formulated in a mucoadhesive carbopol gel (VivaGel®) for use as a topical microbicide. Previous studies showed that SPL7013 has similar potency against CXCR4-(X4) and CCR5-using (R5) strains of HIV-1 and that it blocks viral entry. However, the ability of SPL7013 to directly inactivate HIV-1 is unknown. We examined whether SPL7013 demonstrates virucidal activity against X4 (NL4.3, MBC200, CMU02 clade EA and 92UG046 clade D), R5 (Ba-L, NB25 and 92RW016 clade A) and dual-tropic (R5X4; MACS1-spln) HIV-1 using a modified HLA-DR viral capture method and by polyethylene glycol precipitation. Evaluation of virion integrity was determined by ultracentrifugation through a sucrose cushion and detection of viral proteins by Western blot analysis. SPL7013 demonstrated potent virucidal activity against X4 and R5X4 strains, although virucidal activity was less potent for the 92UG046 X4 clade D isolate. Where potent virucidal activity was observed, the 50% virucidal concentrations were similar to the 50% effective concentrations previously reported in drug susceptibility assays, indicating that the main mode of action of SPL7013 is by direct viral inactivation for these strains. In contrast, SPL7013 lacked potent virucidal activity against R5 HIV-1 strains. Evaluation of the virucidal mechanism showed that SPL7013-treated NL4.3, 92UG046 and MACS1-spln virions were intact with no significant decrease in gp120 surface protein with respect to p24 capsid content compared to the corresponding untreated virus. These studies demonstrate that SPL7013 is virucidal against HIV-1 strains that utilize the CXCR4 coreceptor but not viruses tested in this study that solely use CCR5 by a mechanism that is distinct from virion disruption or loss of gp120. In addition, the mode of action by which SPL7013 prevents infection of cells with X4 and R5X4 strains is likely to differ from R5 strains of HIV-1.
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18
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HIV-1 gp41 core with exposed membrane-proximal external region inducing broad HIV-1 neutralizing antibodies. PLoS One 2011; 6:e18233. [PMID: 21483871 PMCID: PMC3069051 DOI: 10.1371/journal.pone.0018233] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 02/23/2011] [Indexed: 12/04/2022] Open
Abstract
The membrane-proximal external region (MPER) of the HIV-1 gp41 consists of epitopes for the broadly cross-neutralizing monoclonal antibodies 2F5 and 4E10. However, antigens containing the linear sequence of these epitopes are unable to elicit potent and broad neutralizing antibody responses in vaccinated hosts, possibly because of inappropriate conformation of these epitopes. Here we designed a recombinant antigen, designated NCM, which comprises the N- and C-terminal heptad repeats that can form a six-helix bundle (6HB) core and the MPER domain of gp41. Two mutations (T569A and I675V) previously reported to expose the neutralization epitopes were introduced into NCM to generate mutants named NCM(TA), NCM(IV), and NCM(TAIV). Our results showed that NCM and its mutants could react with antibodies specific for 6HB and MPER of gp41, suggesting that these antigens are in the form of a trimer of heterodimer (i.e., 6HB) with three exposed MPER tails. Antigen with double mutations, NCM(TAIV), elicited much stronger antibody response in rabbits than immunogens with single mutation, NCM(TA) and NCM(IV), or no mutation, NCM. The purified MPER-specific antibodies induced by NCM(TAIV) exhibited broad neutralizing activity, while the purified 6HB-specific antibodies showed no detectable neutralizing activity. Our recombinant antigen design supported by an investigation of its underlying molecular mechanisms provides a strong scientific platform for the discovery of a gp41 MPER-based AIDS vaccine.
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Pirrone V, Wigdahl B, Krebs FC. The rise and fall of polyanionic inhibitors of the human immunodeficiency virus type 1. Antiviral Res 2011; 90:168-82. [PMID: 21439325 DOI: 10.1016/j.antiviral.2011.03.176] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 03/01/2011] [Accepted: 03/07/2011] [Indexed: 11/16/2022]
Abstract
Infection by the human immunodeficiency virus type 1 (HIV-1) is an ordered, multistep process involving binding and entry, reverse transcription, integration, viral gene transcription, translation, processing, and finally assembly. Numerous therapeutic and preventive compounds, which are currently available for clinical use or are under preclinical and clinical development, act on at least one of these steps. Polyanionic HIV-1 inhibitors comprise a family of compounds that are generally considered entry inhibitors. The main mechanism of anti-HIV-1 activity associated with these compounds involves electrostatic interactions with HIV-1 glycoprotein 120 that ultimately prevent binding of the virus to target cells. A number of these compounds have been considered for systemic use and for use as microbicides, which are products designed to prevent sexual HIV-1 transmission. These compounds have been studied extensively using in vitro assays of activity, cytotoxicity, and mechanism of action, ex vivo models of HIV-1 transmission, and animal models of in vivo efficacy and toxicity. Three of these polyanionic compounds - cellulose sulfate, carrageenan, and PRO 2000 - were advanced into clinical trials of microbicide safety and efficacy. Although phase I and phase II clinical trials showed these compounds to be safe and well tolerated, none of the phase III trials provided any evidence that these compounds were effective against heterosexual HIV-1 transmission. Furthermore, clinical and in vitro results suggest enhancement of HIV-1 infection in the presence of polyanionic compounds. We discuss the preclinical development of polyanionic HIV-1 inhibitors, the clinical trials of polyanionic compounds used systemically and as topical vaginal microbicides, and the prospects for the future development of these compounds as inhibitors of HIV-1 infection.
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Affiliation(s)
- Vanessa Pirrone
- Department of Microbiology & Immunology, Center for Sexually Transmitted Disease, Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine & Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19102, USA
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20
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Lacey CJ, Woodhall S, Qi Z, Sawant S, Cowen M, McCormack S, Jiang S. Unacceptable side-effects associated with a hyperosmolar vaginal microbicide in a phase 1 trial. Int J STD AIDS 2011; 21:714-7. [PMID: 21139151 DOI: 10.1258/ijsa.2010.010215] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We carried out a phase 1 trial of a candidate vaginal microbicide gel against HIV-1 and other sexually transmitted diseases, which contained cellulose acetate 1,2-benzenedicarboxylate (also known as cellulose acetate phthalate) in a glycerol-based vehicle. We had to terminate the study after five women had completed dosing, due to all women experiencing unacceptable vulvo-vaginal side-effects. Further investigations showed that the gel had a very high osmolality, which we believe led to excessive fluid transudation across the vaginal mucosa and acute mucosal dysfunction. We also showed that the rheology of the gel changed dramatically on fluid dilution. The osmolality and rheology of candidate microbicides and other genital mucosal products should therefore be analysed and considered at an early stage of product development.
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Affiliation(s)
- C J Lacey
- Centre for Immunology and Infection, Hull York Medical School, University of York, York, UK.
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21
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Ariën KK, Jespers V, Vanham G. HIV sexual transmission and microbicides. Rev Med Virol 2011; 21:110-33. [PMID: 21412935 DOI: 10.1002/rmv.684] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/25/2011] [Accepted: 01/26/2011] [Indexed: 12/12/2022]
Abstract
Pathogens often rely on the contacts between hosts for transmission. Most viruses have adapted their transmission mechanisms to defined behaviours of their host(s) and have learned to exploit these for their own propagation. Some viruses, such as HIV, the human papillomavirus (HPV), HSV-2 and HCV, cause sexually transmitted infections (STIs). Understanding the transmission of particular viral variants and comprehending the early adaptation and evolution is fundamental to eventually inhibiting sexual transmission of HIV. Here, we review the current understanding of the mechanisms of sexual transmission and the biology of the transmitted HIV. Next, we present a timely overview of candidate microbicides, including past, ongoing and future clinical trials of HIV topical microbicides.
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Affiliation(s)
- Kevin K Ariën
- Virology Unit, Department of Microbiology, Institute of Tropical Medicine, Antwerpen, Belgium.
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22
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Combinatorial approaches to the prevention and treatment of HIV-1 infection. Antimicrob Agents Chemother 2011; 55:1831-42. [PMID: 21343462 DOI: 10.1128/aac.00976-10] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The discovery of the human immunodeficiency virus type 1 (HIV-1) in 1982 soon led to the identification and development of antiviral compounds to be used in treatment strategies for infected patients. Early in the epidemic, drug monotherapies frequently led to treatment failures because the virus quickly developed resistance to the single drug. Following the advent of highly active antiretroviral therapy (HAART) in 1995, dramatic improvements in HIV-1-infected patient health and survival were realized as more refined combination therapies resulted in reductions in viral loads and increases in CD4+ T-cell counts. In the absence of an effective vaccine, prevention of HIV-1 infection has also gained traction as an approach to curbing the pandemic. The development of compounds as safe and effective microbicides has intensified and has focused on blocking the transmission of HIV-1 during all forms of sexual intercourse. Initial preclinical investigations and clinical trials of microbicides focused on single compounds effective against HIV-1. However, the remarkable successes achieved using combination therapy to treat systemic HIV-1 infection have subsequently stimulated the study and development of combination microbicides that will simultaneously inhibit multiple aspects of the HIV-1 transmission process by targeting incoming viral particles, virus-infected cells, and cells susceptible to HIV-1 infection. This review focuses on existing and developing combination therapies, covering preclinical development, in vitro and in vivo efficacy studies, and subsequent clinical trials. The shift in focus within the microbicide development field from single compounds to combination approaches is also explored.
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23
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Identification of a gp41 core-binding molecule with homologous sequence of human TNNI3K-like protein as a novel human immunodeficiency virus type 1 entry inhibitor. J Virol 2010; 84:9359-68. [PMID: 20592080 DOI: 10.1128/jvi.00644-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) gp41 plays a critical role in the viral fusion process, and its N- and C-terminal heptad repeat domains serve as important targets for developing anti-HIV-1 drugs, like T-20 (generic name, enfuvirtide; brand name, Fuzeon). Here, we conducted a yeast two-hybrid screening on a human bone marrow cDNA library using the recombinant soluble gp41 ectodomain as the bait and identified a novel gp41 core-binding molecule, designated P20. P20 showed no homology with a current HIV fusion inhibitor, T-20, but had sequence homology to a human protein, troponin I type 3 interacting kinase (TNNI3K)-like protein. While it could bind to the six-helix bundle core structure formed by the N- and C-terminal heptad repeats, P20 did not interrupt the formation of the six-helix bundle. P20 was effective in blocking HIV-1 Env-mediated syncytium formation and inhibiting infection by a broad spectrum of HIV-1 strains with distinct subtypes and coreceptor tropism, while it was ineffective against other enveloped viruses, such as vesicular stomatitis virus and influenza A virus. P20 exhibited no significant cytotoxicity to the CD4(+) cells that were used for testing antiviral activity. Among the 11 P20 mutants, four analogous peptides with a common motif (WGRLEGRRT) exhibited significantly reduced anti-HIV-1 activity, suggesting that this region is the critical active site of P20. Therefore, this peptide can be used as a lead for developing novel HIV fusion inhibitors and as a probe for studying the membrane-fusogenic mechanism of HIV.
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3-hydroxyphthalic anhydride-modified chicken ovalbumin exhibits potent and broad anti-HIV-1 activity: a potential microbicide for preventing sexual transmission of HIV-1. Antimicrob Agents Chemother 2010; 54:1700-11. [PMID: 20194691 DOI: 10.1128/aac.01046-09] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heterosexual transmission is the primary route by which women acquire human immunodeficiency virus (HIV)/AIDS. Thus, development of woman-controlled topical microbicides for prevention of sexual transmission of HIV is urgently needed. Here we report that 3-hydroxyphthalic anhydride-modified chicken ovalbumin (HP-OVA) exhibits potent antiviral activity against a broad spectrum of human immunodeficiency virus type 1 (HIV-1) isolates with different genotypes and biotypes. Its antiviral activity is correlated with the percentages of the chemically modified and unmodified lysines and arginines in OVA. HP-OVA inhibits HIV-1 fusion and entry through multiple mechanisms of action, including (i) blocking gp120 binding to CD4 and (ii) interfering with gp41 six-helix bundle formation. Because of the widespread availability and established safety profile of OVA, HP-OVA has good potential to be developed as an effective, safe, and affordable microbicide for prevention of HIV sexual transmission.
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25
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Olaru N, Olaru L. Electrospinning of Cellulose Acetate Phthalate from Different Solvent Systems. Ind Eng Chem Res 2010. [DOI: 10.1021/ie901427f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Niculae Olaru
- “Petru Poni” Institute of Macromolecular Chemistry, Aleea Grigore Ghica-Voda 41A, Iasi 700487, Romania
| | - Liliana Olaru
- “Petru Poni” Institute of Macromolecular Chemistry, Aleea Grigore Ghica-Voda 41A, Iasi 700487, Romania
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Abstract
Biodegradable plastics are those that can be completely degraded in landfills, composters or sewage treatment plants by the action of naturally occurring micro-organisms. Truly biodegradable plastics leave no toxic, visible or distinguishable residues following degradation. Their biodegradability contrasts sharply with most petroleum-based plastics, which are essentially indestructible in a biological context. Because of the ubiquitous use of petroleum-based plastics, their persistence in the environment and their fossil-fuel derivation, alternatives to these traditional plastics are being explored. Issues surrounding waste management of traditional and biodegradable polymers are discussed in the context of reducing environmental pressures and carbon footprints. The main thrust of the present review addresses the development of plant-based biodegradable polymers. Plants naturally produce numerous polymers, including rubber, starch, cellulose and storage proteins, all of which have been exploited for biodegradable plastic production. Bacterial bioreactors fed with renewable resources from plants – so-called ‘white biotechnology’ – have also been successful in producing biodegradable polymers. In addition to these methods of exploiting plant materials for biodegradable polymer production, the present review also addresses the advances in synthesizing novel polymers within transgenic plants, especially those in the polyhydroxyalkanoate class. Although there is a stigma associated with transgenic plants, especially food crops, plant-based biodegradable polymers, produced as value-added co-products, or, from marginal land (non-food), crops such as switchgrass (Panicum virgatum L.), have the potential to become viable alternatives to petroleum-based plastics and an environmentally benign and carbon-neutral source of polymers.
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27
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Xie L, Guo HF, Lu H, Zhuang XM, Zhang AM, Wu G, Ruan JX, Zhou T, Yu D, Qian K, Lee KH, Jiang S. Development and preclinical studies of broad-spectrum anti-HIV agent (3'R,4'R)-3-cyanomethyl-4-methyl-3',4'-di-O-(S)-camphanoyl-(+)-cis-khellactone (3-cyanomethyl-4-methyl-DCK). J Med Chem 2009; 51:7689-96. [PMID: 19053755 DOI: 10.1021/jm8003009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In prior investigation, we discovered that (3'R,4'R)-3-cyanomethyl-4-methyl-3',4'-di-O-(S)-camphanoyl-(+)-cis-khellactone (4, 3-cyanomethyl-4-methyl-DCK) showed promising anti-HIV activity. In these current studies, we developed and optimized successfully a practical 10-step synthesis for scale-up preparation to increase the overall yield of 4 from 7.8% to 32%. Furthermore, compound 4 exhibited broad-spectrum anti-HIV activity against wild-type and drug-resistant viral infection of CD4+ T cell lines as well as peripheral blood mononuclear cells by both laboratory-adapted and primary HIV-1 isolates with distinct subtypes and tropisms. Compound 4 was further subjected to in vitro and in vivo pharmacokinetic studies. These studies indicated that 4 has moderate cell permeability, moderate oral bioavailability, and low systemic clearance. These results suggest that 4 should be developed as a promising anti-HIV agent for development as a clinical trial candidate.
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Affiliation(s)
- Lan Xie
- Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing 100850, China.
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28
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Ghosh T, Chattopadhyay K, Marschall M, Karmakar P, Mandal P, Ray B. Focus on antivirally active sulfated polysaccharides: from structure-activity analysis to clinical evaluation. Glycobiology 2008; 19:2-15. [PMID: 18815291 DOI: 10.1093/glycob/cwn092] [Citation(s) in RCA: 262] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In recent years, many compounds having potent antiviral activity in cell culture have been detected and some of these compounds are currently undergoing either preclinical or clinical evaluation. Among these antiviral substances, naturally occurring sulfated polysaccharides and those from synthetic origin are noteworthy. Recently, several controversies over the molecular structures of sulfated polysaccharides, viral glycoproteins, and cell-surface receptors have been resolved, and many aspects of their antiviral activity have been elucidated. It has become clear that the antiviral properties of sulfated polysaccharides are not only a simple function of their charge density and chain length but also their detailed structural features. The in vivo efficacy of these compounds mostly corresponds to their ability to inhibit the attachment of the virion to the host cell surface although in some cases virucidal activity plays an additional role. This review summarizes experimental evidence indicating that sulfated polysaccharides might become increasingly important in drug development for the prevention of sexually transmitted diseases in the near future.
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Affiliation(s)
- Tuhin Ghosh
- Department of Chemistry, Natural Products Laboratory, University of Burdwan, WB 713 104, India
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29
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Huang JH, Qi Z, Wu F, Kotula L, Jiang S, Chen YH. Interaction of HIV-1 gp41 core with NPF motif in Epsin: implication in endocytosis of HIV. J Biol Chem 2008; 283:14994-5002. [PMID: 18375383 DOI: 10.1074/jbc.m800525200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human immunodeficiency virus, type 1 (HIV-1), gp41 core plays an important role in fusion between viral and target cell membranes. We previously identified an HIV-1 gp41 core-binding motif HXXNPF (where X is any amino acid residue). In this study, we found that Asn, Pro, and Phe were the key residues for gp41 core binding. There are two NPF motifs in Epsin-1-(470-499), a fragment of Epsin, which is an essential accessory factor of endocytosis that can dock to the plasma membrane by interacting with the lipid. Epsin-1-(470-499) bound significantly to the gp41 core formed by the polypeptide N36(L8)C34 and interacted with the recombinant soluble gp41 containing the core structure. A synthetic peptide containing the Epsin-1-(470-499) sequence could effectively block entry of HIV-1 virions into SupT1 T cells via the endocytosis pathway. These results suggest that interaction between Epsin and the gp41 core, which may be present in the target cell membrane, is probably essential for endocytosis of HIV-1, an alternative pathway of HIV-1 entry into the target cell.
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Affiliation(s)
- Jing-He Huang
- Laboratory of Immunology, Department of Biology, Tsinghua University, Protein Science Laboratory of the Ministry of Education, Beijing, China
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30
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Turpin JA, Schito ML, Jenkins LMM, Inman JK, Appella E. Topical microbicides: a promising approach for controlling the AIDS pandemic via retroviral zinc finger inhibitors. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2008; 56:229-56. [PMID: 18086414 DOI: 10.1016/s1054-3589(07)56008-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Affiliation(s)
- Jim A Turpin
- Preventions Sciences Program, Division of AIDS, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA
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31
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Gantlett KE, Weber JN, Sattentau QJ. Synergistic inhibition of HIV-1 infection by combinations of soluble polyanions with other potential microbicides. Antiviral Res 2007; 75:188-97. [PMID: 17408760 DOI: 10.1016/j.antiviral.2007.03.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Revised: 02/28/2007] [Accepted: 03/06/2007] [Indexed: 11/21/2022]
Abstract
Several polyanionic compounds with potential for use as topically applied microbicides to prevent HIV-1 sexual transmission, such as PRO 2000, are currently in phase III clinical efficacy trials. Microbicidal formulations may well comprise combinations of inhibitors to increase potency, reduce dose and minimize problems of HIV-1 resistance. We have therefore evaluated in vitro, the anti-HIV-1 activity of two leading polyanionic microbicides combined with other antiretroviral agents with microbicidal potential. Dextran sulfate (DS) and PRO 2000 were combined with the neutralizing antibody IgG1b12, the peptide-based fusion inhibitor T20, the CCR5 antagonist TAK779 and the cyanobacterial protein cyanovirin-N. Anti-HIV-1 activity was assessed in a single cycle replication assay using pseudoviruses carrying a luciferase reporter gene and the envelope glycoproteins from HIV-1 isolates JR-FL (R5) and HxB2 (X4), against both immortalized and primary CD4+ cell targets. The data were analyzed for synergy using Calcusyn software. Results indicate that PRO 2000 and DS can act synergistically with most inhibitors tested, although the degree of synergy depends on inhibitor concentration and combination. These data provide a rational basis for testing of microbicide combinations in vivo.
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Affiliation(s)
- Katherine E Gantlett
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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32
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Roth S, Monsour M, Dowland A, Guenthner PC, Hancock K, Ou CY, Dezzutti CS. Effect of topical microbicides on infectious human immunodeficiency virus type 1 binding to epithelial cells. Antimicrob Agents Chemother 2007; 51:1972-8. [PMID: 17404008 PMCID: PMC1891390 DOI: 10.1128/aac.01358-06] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Topical microbicides (cellulose acetate 1,2 benzene dicarboxylate [CAP], PRO 2000, SPL7013, and UC781) are being investigated to reduce the sexual transmission of human immunodeficiency virus type 1 (HIV-1). These products were shown to prevent the transfer of infectious HIV-1 from urogenital and colorectal epithelial cell lines to peripheral blood mononuclear cells. However, it was unclear if the topical microbicides rendered the virus noninfectious and/or reduced the binding to the epithelial cells. To test this, epithelial cells were cultured with HIV-1 in the presence or absence of topical microbicides or their placebos. The cells were washed, RNA lysates were made, and real-time PCR was performed for HIV-1. PRO 2000 and SPL7013 significantly (P < 0.0001) reduced the amount of bound HIV-1 to the colorectal epithelial cell line across clades A, B, C, and CRF01-AE. While none of the products reduced the binding of HIV-1 clades A and C to the urogenital cell line, CAP, PRO 2000, and SPL7013 significantly (P </= 0.002) reduced the binding of clades B and CRF01-AE. In general, PRO 2000 and SPL7013 placebos significantly (P < 0.0001) reduced the amount of bound HIV-1 but were less than the active products. UC781, its placebo, and hydroxyethyl cellulose (placebo for CAP) minimally affected the amount of bound HIV-1. These results suggest that rendering HIV-1 noninfectious may not correlate to the amount of HIV-1 bound to epithelial cells and possible shedding into mucosal secretions. Therefore, functional virological assays in addition to measuring viral RNA should be included when clinically evaluating topical microbicide use by infected persons.
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Affiliation(s)
- Susan Roth
- University of Pittsburgh, Department of Obstetrics, Gynecology, and Reproductive Sciences, Magee-Womens Research Institute, 204 Craft Avenue, Pittsburgh, PA 15213, USA
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33
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Abstract
25 years after the first HIV/AIDS cases emerged in 1981, the disease continues to spread worldwide, with about 15 000 new infections every day. Although highly active antiretroviral therapy (HAART) has greatly reduced the rate of HIV infection, and the spread of the epidemic, this effect has largely been seen in developed countries. More than 90% of HIV-infected people live in developing countries, most of whom do not have access to this treatment. The development of efficient, widely available, and low-cost microbicides (gels and creams can be applied topically before sex) to prevent sexually transmitted HIV infections should be given high priority. We review different categories of microbicide drugs and lead compounds, their mechanism of action, current status of development, and progress in phase III trials.
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Affiliation(s)
- Jan Balzarini
- Rega Institute for Medical Research, K U Leuven, B-3000 Leuven, Belgium.
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34
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Sugaya M, Hartley O, Root MJ, Blauvelt A. C34, a membrane fusion inhibitor, blocks HIV infection of langerhans cells and viral transmission to T cells. J Invest Dermatol 2007; 127:1436-43. [PMID: 17255952 DOI: 10.1038/sj.jid.5700736] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Development of topical microbicides that prevent sexual transmission of HIV is an active area of investigation. The purpose of this study was to test the ability of the potent membrane fusion inhibitor C34, an HIV gp41 antagonist, to block HIV infection of human Langerhans cells (LCs) in an epithelial environment that mimics a major route of HIV infection. We incubated freshly isolated epidermal explants containing LCs with various doses of C34 before, during, and after exposing explants to HIV. Although C34 only partially blocked HIV infection of LCs when pre-incubated with skin, it displayed full, dose-dependent inhibition when present during and after viral exposure. The poor protection from HIV infectivity in pre-incubated samples is consistent with mechanism of C34 inhibition and starkly contrasts to the full protection provided by PSC-RANTES, an entry inhibitor that prevents HIV gp120 interaction with its co-receptor CCR5. Real-time PCR confirmed that C34 blocked HIV infection of LCs before reverse transcription and inhibited LC-mediated transfer of virus to T cells. We conclude that C34, if used topically at susceptible mucosal sites, and if continually present, has the potential to block sexual transmission of HIV.
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Affiliation(s)
- Makoto Sugaya
- Dermatology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
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35
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Huang JH, Lu L, Lu H, Chen X, Jiang S, Chen YH. Identification of the HIV-1 gp41 core-binding motif in the scaffolding domain of caveolin-1. J Biol Chem 2006; 282:6143-52. [PMID: 17197700 DOI: 10.1074/jbc.m607701200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human immunodeficiency virus, type 1 (HIV-1) gp41 core plays an important role in fusion between viral and target cell membranes. A single chain polypeptide, N36(L8)C34, which forms a six-helix bundle in physiological solution, can be used as a model of gp41 core. Here we identified from a 12-mer phage peptide library a positive phage clone displaying a peptide sequence with high binding activity to the HIV-1 gp41 core. The peptide sequence contains a putative gp41-binding motif, PhiXXXXPhiXPhi (X is any amino acid residue, and Phi is any one of the aromatic amino acid residues Trp, Phe, or Tyr). This motif also exists in the scaffolding domain of caveolin-1 (Cav-1), a known gp41-binding protein. Cav-1-(61-101) and Cav-1-(82-101), two recombinant fusion proteins containing the Cav-1 scaffolding domain, bound significantly to the gp41 expressed in mammalian cells and interacted with the polypeptide N36(L8)C34. These results suggest that the scaffolding domain of Cav-1 may bind to the gp41 core via the motif. This interaction may be essential for formation of fusion pore or endocytosis of HIV-1 and affect the pathogenesis of HIV-1 infection. Further characterization of the gp41 core-binding motifs may shed light on the alternative mechanism by which HIV-1 enters into the target cell.
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Affiliation(s)
- Jing-He Huang
- Laboratory of Immunology, Department of Biology, Tsinghua University, Protein Science Laboratory of the Ministry of Education, Beijing 100084, P.R. China
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36
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Rando RF, Obara S, Osterling MC, Mankowski M, Miller SR, Ferguson ML, Krebs FC, Wigdahl B, Labib M, Kokubo H. Critical design features of phenyl carboxylate-containing polymer microbicides. Antimicrob Agents Chemother 2006; 50:3081-9. [PMID: 16940105 PMCID: PMC1563534 DOI: 10.1128/aac.01609-05] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent studies of cellulose-based polymers substituted with carboxylic acids like cellulose acetate phthalate (CAP) have demonstrated the utility of using carboxylic acid groups instead of the more common sulfate or sulfonate moieties. However, the pK(a) of the free carboxylic acid group is very important and needs careful selection. In a polymer like CAP the pK(a) is approximately 5.28. This means that under the low pH conditions found in the vaginal lumen, CAP would be only minimally soluble and the carboxylic acid would not be fully dissociated. These issues can be overcome by substitution of the cellulose backbone with a moiety whose free carboxylic acid group(s) has a lower pK(a). Hydroxypropyl methylcellulose trimellitate (HPMCT) is structurally similar to CAP; however, its free carboxylic acids have pK(a)s of 3.84 and 5.2. HPMCT, therefore, remains soluble and molecularly dispersed at a much lower pH than CAP. In this study, we measured the difference in solubility and dissociation between CAP and HPMCT and the effect these parameters might have on antiviral efficacy. Further experiments revealed that the degree of acid substitution of the cellulose backbone can significantly impact the overall efficacy of the polymer, thereby demonstrating the need to optimize any prospective polymer microbicide with respect to pH considerations and the degree of acid substitution. In addition, we have found HPMCT to be a potent inhibitor of CXCR4, CCR5, and dual tropic strains of human immunodeficiency virus in peripheral blood mononuclear cells. Therefore, the data presented herein strongly support further evaluation of an optimized HPMCT variant as a candidate microbicide.
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Affiliation(s)
- Robert F Rando
- Novaflux Biosciences, Inc., 1 Wall Street, Princeton, New Jersey 08540, USA.
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37
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McGowan I. Microbicides: a new frontier in HIV prevention. Biologicals 2006; 34:241-55. [PMID: 17097303 DOI: 10.1016/j.biologicals.2006.08.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Accepted: 08/24/2006] [Indexed: 01/01/2023] Open
Abstract
Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections (STIs) including HIV-1. Despite more than two decades of HIV-1 vaccine research, there is still no efficacious HIV-1 vaccine, and the scientific community appears skeptical about the short or long-term feasibility of developing a vaccine that has the ability to induce sterilizing immunity against HIV-1. In this setting, microbicide research has gathered momentum. Currently, 16 candidate microbicides are in clinical development and five products are being evaluated in large-scale Phase 2B/3 effectiveness studies. Initial data from these trials will be available within the next 2-3 years, and it is feasible that there could be one or more licensed microbicides by the end of the decade. The first generation of surfactant microbicides had a non-specific mechanism of action. However, subsequent candidate microbicides have been developed to target specific steps in the process of viral transmission. The purpose of this article is to provide an overview of microbicide development and an update on the candidate pipeline.
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Affiliation(s)
- Ian McGowan
- Center for Prevention Research, David Geffen School of Medicine at UCLA, Los Angeles, 10940 Wilshire Boulevard, Suite 1250, Los Angeles, CA 90025, USA.
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38
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Lu H, Zhao Q, Wallace G, Liu S, He Y, Shattock R, Neurath AR, Jiang BS. Cellulose acetate 1,2-benzenedicarboxylate inhibits infection by cell-free and cell-associated primary HIV-1 isolates. AIDS Res Hum Retroviruses 2006; 22:411-8. [PMID: 16706617 PMCID: PMC2788998 DOI: 10.1089/aid.2006.22.411] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cellulose acetate 1,2-benzenedicarboxylate (CAP), a pharmaceutical excipient used for enteric film coating of capsules and tablets, was previously shown to have potent inhibitory activity against infection by human immunodeficiency virus type 1 (HIV-1) T cell line-adapted (TCLA) strains. In the present study, we determined the inhibitory activity of CAP against infection by cell-free and cell-associated primary HIV-1 isolates with distinct genotypes and biotypes in cervical explants, peripheral blood mononuclear cells (PBMCs), monocytederived macrophages (MDMs), and CEMx174 5.25M7 cells. CAP blocked infection by cell-free and cell-associated HIV-1 in cervical explants. It inhibited infection by cell-free primary HIV-1 isolates (clades A to G and group O) in PBMCs, MDMs, and CEMx174 5.25M7 cells and blocked transmissions of the cell-associated primary HIV-1 isolates from dendritic cells (DCs) to PBMCs, from MDMs to PBMCs, and from PBMCs to CEMx174 5.25M7 cells. The inhibitory activity of CAP on infection by the cell-free and cell-associated primary HIV-1 isolates is independent of viral subtypes and coreceptor usage. These data suggest that CAP is a good microbicide candidate that can be further developed for preventing sexual transmission of HIV-1.
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Affiliation(s)
- Hong Lu
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York 10021, USA
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39
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Scordi-Bello IA, Mosoian A, He C, Chen Y, Cheng Y, Jarvis GA, Keller MJ, Hogarty K, Waller DP, Profy AT, Herold BC, Klotman ME. Candidate sulfonated and sulfated topical microbicides: comparison of anti-human immunodeficiency virus activities and mechanisms of action. Antimicrob Agents Chemother 2005; 49:3607-15. [PMID: 16127029 PMCID: PMC1195443 DOI: 10.1128/aac.49.9.3607-3615.2005] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Poly(styrene 4-sulfonate), cellulose sulfate, polymethylenehydroquinone, and PRO 2000 are sulfated or sulfonated polymers (SPs) under development as topical microbicides. They are presumed to work through similar mechanisms of action, although to date there has been no extensive comparison of their anti-human immunodeficiency virus activities. To determine whether any of these candidate microbicides offers a potential advantage, their in vitro activities, mechanisms of action, stabilities in biological secretions, and toxicities were compared. All four compounds were found to be active against X4, R5, and dualtropic primary isolates and against X4 and R5 laboratory-adapted strains in CD4+ T cells, macrophages, and single-coreceptor cell lines. Our single-cycle experiments using pseudotyped virus suggest that all four SPs function at the binding and entry stages of the viral life cycle but differ in degree of postentry effect. Surface plasmon resonance analyses demonstrate that SPs bind to X4 and R5 monomeric glycoprotein 120 with similar high binding affinities. When mixed with cervicovaginal lavage fluid, SPs maintain inhibitory activity at concentrations achievable in formulations.
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Affiliation(s)
- Irini A Scordi-Bello
- Department of Medicine, Mount Sinai School of Medicine, Box 1090, New York, NY 10029, USA
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40
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Boadi T, Schneider E, Chung S, Tsai L, Gettie A, Ratterree M, Blanchard J, Neurath AR, Cheng-Mayer C. Cellulose acetate 1,2-benzenedicarboxylate protects against challenge with pathogenic X4 and R5 simian/human immunodeficiency virus. AIDS 2005; 19:1587-94. [PMID: 16184027 DOI: 10.1097/01.aids.0000186020.24426.62] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To evaluate the protective efficacy of cellulose acetate 1,2-benzenedicarboxylate (CAP) formulated in a glycerol-based gel against infection with CXCR4 (X4) and CCR5 (R5) viruses in the simian/human immunodeficiency virus (SHIV)/rhesus macaque model of HIV-1 transmission. DESIGN Mucosal infection of non-human primates is a reasonable model for use in the investigation of HIV-1 intervention strategies. METHODS Rhesus macaques treated with Depo-Provera 5 weeks prior to challenge were inoculated intravaginally twice, over a period of 6 h with mixed inocula of pathogenic X4- and R5-SHIV in the presence or absence of CAP. Plasma viral load, peripheral and mucosal CD4 T cell counts as well as the genotype of the circulating virus were determined. RESULTS CAP protected seven of ten macaques against transmission of both X4- and R5-SHIV, reaching statistically significant values (P = 0.0256). Delayed and/or reduced virus replication, as well as blunting of peripheral and mucosal CD4 T cell loss was noted in the three macaques that were infected in the CAP treated group compared to those in the placebo group. Further, protection conferred by CAP appeared to be more effective against X4- than R5-SHIV infection. CONCLUSIONS CAP is protective against highly permissive challenges with X4 and R5 viruses in vivo. Research on further development of this promising compound as a candidate microbicide for the prevention of sexual HIV-1 transmission is therefore warranted.
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Affiliation(s)
- Tina Boadi
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NY 10016, USA
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41
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Doncel G, Mauck C. Vaginal microbicides: a novel approach to preventing sexual transmission of HIV. Curr HIV/AIDS Rep 2005; 1:25-32. [PMID: 16091220 DOI: 10.1007/s11904-004-0004-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The AIDS epidemic continues its unrelentless expansion. According to the Joint United Nations Programme on HIV/AIDS, there are more than 40 million people living with HIV, and more than 15,000 new infections occur every day. One approach to curbing HIV is the development of topical microbicidal agents or microbicides. These are compounds designed to protect the body's mucosal surfaces from infection by sexually transmitted disease-causing pathogens, including HIV. Several candidates are in preclinical stages; however, only a handful have been tested in humans for safety, and even fewer are ready for clinical efficacy trials. In this update, we describe microbicide research and development, including preclinical screening algorithms, ideal properties, compounds in the pipeline, and future prospects. This review is based on a previous work, which has been updated to contain new information, especially regarding microbicide candidates in preclinical and clinical stages of development.
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Affiliation(s)
- Gustavo Doncel
- CONRAD, Eastern Virginia Medical School, 601 Colley Avenue, Norfolk, VA 23507, USA.
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42
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Moscona A. Entry of parainfluenza virus into cells as a target for interrupting childhood respiratory disease. J Clin Invest 2005; 115:1688-98. [PMID: 16007245 PMCID: PMC1159152 DOI: 10.1172/jci25669] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Human parainfluenza viruses cause several serious respiratory diseases in children for which there is no effective prevention or therapy. Parainfluenza viruses initiate infection by binding to cell surface receptors and then, via coordinated action of the 2 viral surface glycoproteins, fuse directly with the cell membrane to release the viral replication machinery into the host cell's cytoplasm. During this process, the receptor-binding molecule must trigger the viral fusion protein to mediate fusion and entry of the virus into a cell. This review explores the binding and entry into cells of parainfluenza virus type 3, focusing on how the receptor-binding molecule triggers the fusion process. There are several steps during the process of binding, triggering, and fusion that are now understood at the molecular level, and each of these steps represents potential targets for interrupting infection.
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Affiliation(s)
- Anne Moscona
- Department of Pediatrics, Weill Medical College of Cornell University, New York, NY 10021, USA.
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43
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Liu S, Lu H, Neurath AR, Jiang S. Combination of candidate microbicides cellulose acetate 1,2-benzenedicarboxylate and UC781 has synergistic and complementary effects against human immunodeficiency virus type 1 infection. Antimicrob Agents Chemother 2005; 49:1830-6. [PMID: 15855503 PMCID: PMC1087640 DOI: 10.1128/aac.49.5.1830-1836.2005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The combination of two candidate microbicides, cellulose acetate 1,2-benzenedicarboxylate (CAP), a polymer that blocks human immunodeficiency virus type 1 (HIV-1) entry by targeting gp120 and gp41, and UC781, a tight-binding HIV-1 reverse transcriptase inhibitor (RTI), resulted in effective synergy for inhibition of MT-2 cell infection by HIV-1(IIIB), a laboratory-adapted virus strain. The 95% effective concentration values for the combination were reduced about 15- to 20-fold compared with those corresponding to the single compounds. The combination of CAP and UC781 is also synergistic in inhibiting infection of peripheral blood mononuclear cells by a primary HIV-1 isolate, 92US657. Combinations of CAP with other RTIs, such as efavirenz or zidovudine, also had significant synergistic effects on the inhibition of HIV-1 infection. In addition, CAP and UC781 had complementary effects against HIV-1 infection since (i) CAP inhibited infection by the UC781-resistant strain HIV-1(IIIB) A17 and (ii) pretreatment of MT-2 cells with UC781, but not CAP, abolished subsequent infection after removal of the compound. This suggests that the combination of CAP and UC781 represents a promising candidate microbicide for prevention of sexual transmission of HIV-1.
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Affiliation(s)
- Shuwen Liu
- Lindsley F. Kimball Research Institute, New York Blood Center, 310 E 67th St., New York, NY 10021, USA
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44
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Fichorova RN, Zhou F, Ratnam V, Atanassova V, Jiang S, Strick N, Neurath AR. Anti-human immunodeficiency virus type 1 microbicide cellulose acetate 1,2-benzenedicarboxylate in a human in vitro model of vaginal inflammation. Antimicrob Agents Chemother 2005; 49:323-35. [PMID: 15616312 PMCID: PMC538889 DOI: 10.1128/aac.49.1.323-335.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The sexual transmission of human immunodeficiency virus type 1 (HIV-1) is facilitated by inflammation and related epithelial barrier perturbation. Microbicides for vaginal applications are currently being developed to reduce the risk of HIV-1 transmission. However, little is known about their interference with epithelial immune function. In recent clinical trials, nonoxynol-9 (N-9), a virucide with a long history of intravaginal use as a contraceptive, failed to protect against HIV-1 possibly due to mucosal inflammatory damage. Cellulose acetate 1,2-benzenedicarboxylate, also named CAP (for "controls AIDS pandemic"), is an anti-HIV-1 microbicide selected from pharmaceutical excipients that are regarded as safe for oral administration but have not been assessed for potential effects on inflammatory factors in the vaginal environment. Here we use a sensitive human cell culture system to evaluate proinflammatory profiles of soluble CAP in reference to N-9 and known epithelial activators such as tumor necrosis factor alpha (TNF-alpha) and bacterial lysates. Within 6 h of exposure, TNF-alpha and N-9 triggered NF-kappaB and AP-1/cFos activation and upregulated interleukins and an array of chemokines by vaginal and polarized cervical epithelial cells. The induced proinflammatory status continued after removal of stimuli and was confirmed by enhanced transepithelial neutrophil migration. While sustaining stability and anti-HIV-1 activity in the epithelial environment, CAP did not increase the production of proinflammatory mediators during or after exposure, nor did it modify the epithelial resistance to leukocyte traffic. CAP attenuated some TNF-alpha-induced responses but did not interfere with epithelial cytokine responsiveness to gonococcal determinants. The described system may be useful for predicting proinflammatory side effects of other microbicide candidates for vaginal application.
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Affiliation(s)
- R N Fichorova
- Laboratory of Genital Tract Biology, Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, 221 Longwood Ave. RF468, Boston, MA 02115, USA.
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45
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Dezzutti CS, James VN, Ramos A, Sullivan ST, Siddig A, Bush TJ, Grohskopf LA, Paxton L, Subbarao S, Hart CE. In vitro comparison of topical microbicides for prevention of human immunodeficiency virus type 1 transmission. Antimicrob Agents Chemother 2004; 48:3834-44. [PMID: 15388443 PMCID: PMC521884 DOI: 10.1128/aac.48.10.3834-3844.2004] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A standardized protocol was used to compare cellular toxicities and anti-human immunodeficiency virus type 1 (HIV-1) activities of candidate microbicides formulated for human use. The microbicides evaluated were cellulose acetate phthalate (CAP), Carraguard, K-Y plus nonoxynol-9 (KY-N9), PRO 2000 (0.5 and 4%), SPL7013 (5%), UC781 (0.1 and 1%), and Vena Gel, along with their accompanying placebos. Products were evaluated for toxicity on cervical and colorectal epithelial cell lines, peripheral blood mononuclear cells (PBMCs), and macrophages (MPhi) by using an ATP release assay, and they were tested for their effect on transepithelial resistance (TER) of polarized epithelial monolayers. Anti-HIV-1 activity was evaluated in assays for transfer of infectious HIV-1 from epithelial cells to activated PBMCs and for PBMC and MPhi infection. CAP, Carraguard, PRO 2000, SPL7013, and UC781 along with their placebos were 20- to 50-fold less toxic than KY-N9 and Vena Gel. None of the nontoxic product concentrations disrupted the TER. Transfer of HIV-1(Ba-L) from epithelial cells to PBMCs and PBMC and MPhi infection with laboratory-adapted HIV-1(Ba-L) and HIV-1(LAI) isolates were inhibited by all products except Carraguard, KY-N9, and Vena Gel. KY-N9, Vena Gel, and Carraguard were not effective in blocking PBMC infection with primary HIV-1(A), HIV-1(C), and HIV-1(CRF01-AE) isolates. The concordance of these toxicity results with those previously reported indicates that our protocol may be useful for predicting toxicity in vivo. Moreover, our systematic anti-HIV-1 testing provides a rational basis for making better informed decisions about which products to consider for clinical trials.
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Affiliation(s)
- Charlene S Dezzutti
- Centers for Disease Control and Prevention, 1600 Clifton Rd., NE, Mailstop G19, Atlanta, GA 30333, USA.
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46
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Neurath AR, Strick N, Li YY, Debnath AK. Punica granatum (Pomegranate) juice provides an HIV-1 entry inhibitor and candidate topical microbicide. BMC Infect Dis 2004; 4:41. [PMID: 15485580 PMCID: PMC533885 DOI: 10.1186/1471-2334-4-41] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Accepted: 10/14/2004] [Indexed: 11/10/2022] Open
Abstract
Background For ≈ 24 years the AIDS pandemic has claimed ≈ 30 million lives, causing ≈ 14,000 new HIV-1 infections daily worldwide in 2003. About 80% of infections occur by heterosexual transmission. In the absence of vaccines, topical microbicides, expected to block virus transmission, offer hope for controlling the pandemic. Antiretroviral chemotherapeutics have decreased AIDS mortality in industrialized countries, but only minimally in developing countries. To prevent an analogous dichotomy, microbicides should be: acceptable; accessible; affordable; and accelerative in transition from development to marketing. Already marketed pharmaceutical excipients or foods, with established safety records and adequate anti-HIV-1 activity, may provide this option. Methods Fruit juices were screened for inhibitory activity against HIV-1 IIIB using CD4 and CXCR4 as cell receptors. The best juice was tested for inhibition of: (1) infection by HIV-1 BaL, utilizing CCR5 as the cellular coreceptor; and (2) binding of gp120 IIIB and gp120 BaL, respectively, to CXCR4 and CCR5. To remove most colored juice components, the adsorption of the effective ingredient(s) to dispersible excipients and other foods was investigated. A selected complex was assayed for inhibition of infection by primary HIV-1 isolates. Results HIV-1 entry inhibitors from pomegranate juice adsorb onto corn starch. The resulting complex blocks virus binding to CD4 and CXCR4/CCR5 and inhibits infection by primary virus clades A to G and group O. Conclusion These results suggest the possibility of producing an anti-HIV-1 microbicide from inexpensive, widely available sources, whose safety has been established throughout centuries, provided that its quality is adequately standardized and monitored.
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Affiliation(s)
- A Robert Neurath
- Biochemical Virology Laboratory, Lindsley F. Kimball Research Institute, New York Blood Center, New York, USA
| | - Nathan Strick
- Biochemical Virology Laboratory, Lindsley F. Kimball Research Institute, New York Blood Center, New York, USA
| | - Yun-Yao Li
- Biochemical Virology Laboratory, Lindsley F. Kimball Research Institute, New York Blood Center, New York, USA
| | - Asim K Debnath
- Laboratory of Molecular Modeling & Drug Design, Lindsley F. Kimball Research Institute, New York Blood Center, New York, USA
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Rohan LC, Ratner D, McCullough K, Hiller SL, Gupta P. Measurement of anti-HIV activity of marketed vaginal products and excipients using a PBMC-based in vitro assay. Sex Transm Dis 2004; 31:143-8. [PMID: 15076925 DOI: 10.1097/01.olq.0000114655.79109.ed] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVE Because microbicides will be applied topically in the vagina, the active agent must be formulated as a gel or cream by combining the active agent with suitable excipients. Although a number of in vitro methods have been developed for testing anti-HIV activity of microbicides, most of these methods have not been used for testing microbicides as a gel or cream. GOAL The goal of this study was to measure anti-HIV activity of marketed vaginal gel or cream products and excipients. STUDY DESIGN A PBMC-based in vitro method has been developed for the evaluation of anti-HIV activity of gel or cream marketed products and formulated drug delivery systems. This method includes viral exposure to test compounds followed by differential centrifugation and filtration. RESULTS Using this methodology, a number of marketed vaginal products showed 83% to 100% inactivation of a variety of X4 and R5 HIV of different clades. Cell viability as determined by the MTT assay for all marketed products was greater than 90%. Some of the excipients also showed anti-HIV activity (20-90%) of their own. CONCLUSION This knowledge of baseline anti-HIV activity of vaginal products (cream/gel) and excipients is useful for the final formulation and development of anti-HIV microbicides.
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Affiliation(s)
- Lisa Cencia Rohan
- Department of Pharmaceutical Sciences, School of Pharmacy, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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Abstract
The worldwide infection rate for HIV-1 is estimated to be 14,000 per day, but only now, more than 20 years into the epidemic, are the immediate events between exposure to infectious virus and the establishment of infection becoming clear. Defining the mechanisms of HIV-1 transmission, the target cells involved and how the virus attaches to and fuses with these cells, could reveal ways to block the sexual spread of the virus. In this review, we will discuss how our increasing knowledge of the ways in which HIV-1 is transmitted is shaping the development of new, more sophisticated intervention strategies based on the application of vaginal or rectal microbicides.
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Affiliation(s)
- Robin J Shattock
- Department of Cellular and Molecular Medicine, Infectious Diseases, St. George's Hospital Medical School, London, UK.
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Neurath AR, Strick N, Li YY. Water dispersible microbicidal cellulose acetate phthalate film. BMC Infect Dis 2003; 3:27. [PMID: 14617380 PMCID: PMC293437 DOI: 10.1186/1471-2334-3-27] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Accepted: 11/14/2003] [Indexed: 11/21/2022] Open
Abstract
Background Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. Methods CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. Results The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ≈50 to ≈65% ethanol (EtOH). The films are ≈100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. Conclusions Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not have to be removed following application and use. In addition to their potential as topical microbicides, the films have promise for mucosal delivery of pharmaceuticals other than CAP.
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Affiliation(s)
- A Robert Neurath
- Biochemical Virology Laboratory, The Lindsley F. Kimball Research Institute of the New York Blood Center, New York, NY 10021, USA
| | - Nathan Strick
- Biochemical Virology Laboratory, The Lindsley F. Kimball Research Institute of the New York Blood Center, New York, NY 10021, USA
| | - Yun-Yao Li
- Biochemical Virology Laboratory, The Lindsley F. Kimball Research Institute of the New York Blood Center, New York, NY 10021, USA
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Abstract
The fusion of viral membranes with target-cell membranes is an essential step in the entry of enveloped viruses into cells, and recent X-ray structures of paramyxoviral envelope proteins have provided new insights into protein-mediated plasma-membrane fusion. Here, we review our understanding of the structural transitions that are involved in this fusion pathway, compare it to our understanding of influenza virus membrane fusion, and discuss the implications for retroviral membrane fusion.
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Affiliation(s)
- Peter M Colman
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia.
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