Scientific Report 2003-2004 - Cleveland Clinic Lerner Research ...

The AIDS pandemic has been recognizedas one of the most important healththreats of the coming century. Therapeuticinterventions, host immuneresponse, and vacci-nations haveall failed to control the humanimmunodeficiency virus (HIV)epidemic because the virusevolves so rapidly. Our researchis focused on HIV-1 evolution toanswer both basic and clinicalresearch questions about viraldynamics and development ofnew antiretroviral strategies.Clinical Significance ofHIV-1 FitnessMultidrug-resistant (MDR)variants of HIV, with reducedsusceptibility to antiretroviralcompounds from two or more classesof drugs, are now commonly found in treated patients. Inthe absence of drug pressure, the most fit virus would beexpected to be the wild-type virus. But in the presence ofdrug-selective pressure, resistant virus is the most fit virus.However, despite the multitude of in vitro data, we still donot know how this relatively reduced viral fitness couldeventually affect the clinical outcome of patients withMDR virus. Using growth competition experiments andTaqMan ® real-time PCR technology, models of the impactof antiretroviral therapy on HIV-1 fitness and diseaseprogression are being developed.Anti-HIV-1 Mechanisms of CombinationTherapy with IFN-α and Protein TyrosinePhosphatase InhibitorsAlthough advances in HIV/AIDS therapeuticshave caused a decrease in both AIDS incidence anddeath in the U.S. and Europe, treatments withantiretroviral com-binations, host immune response,and vaccinations have all failed to control the HIV type 1(HIV-1) epidemic due to rapid evolution of the virus.Therefore, the need for therapeutic alternatives in thetreatment of HIV infec-tions has become clear.Interferons (IFNs) are part of the natural humandefensive response directed against virus infections,including HIV. Multiple studies have shown thatexogenous IFN type I inhibits HIV-1 replication in vitro.The Department of Molecular BiologyHIV: Fitness and Evolution StudiesLeading to New Antiretroviral TherapiesMiguel E. Quiñones-Mateu,Ph.D.Clinical studies of exogenous IFNs taken alone or incombinations with antiretroviral drugs have shownsome success, especially for earlier HIV-1 primaryinfections. However, the role of IFNsin antiretroviral therapy and AIDSpathogenesis is still unknown. On theother hand, it has been reported thatinhibition of protein tyrosinephosphatases (PTPs, enzymes thatcontrol a diverse array of cellularproces-ses) by sodium stibogluconate(SSG, a drug used for the treatment ofleishmaniasis) enhances the in vitro signalingof IFN type I, perhaps increasingits antiviral effect. We are evaluatingthe in vitro and in vivo anti-HIV-1activity of IFN type I in combinationwith SSG and other PTP inhibitors, toboost the effects of IFNs in antiviraland/or immunotherapeutic treatments.Lethal Mutagenesis as a NewAntiretroviral TherapyTreatments with combinations of antiretroviralmedications do not completely inhibit HIV replication,eventually leading to treatment failure. Thus, there is asubstantial need for the availability of novel agents,which target different sites involved in the virus lifecycle. RNA viruses (such as HIV-1) replicate andevolve as complex mutant distributions termed viralquasi-species, which are powered by error-pronereplication and high mutation frequency. However,maintaining such a high mutation frequency isdangerous for the virus. An increase in the averageerror rate above a critical threshold during viralreplication should result in the loss of geneticinformation in a process that has been referred to asviolation of the error threshold or entry into errorcatastrophe. If an RNA virus quasi-species goesbeyond this mutation limit, the population will nolonger be viable. Interestingly, it has been pre-dictedthat RNA viruses’ high mutation frequencies are closeto this limit and can be forced into error catas-tropheby a moderate increase in mutation rate. This newconcept is opening new avenues for understanding viralinfections, and it should allow an assessment of thepossibilities of lethal mutagenesis as an antiviralstrategy against HIV.VIROLOGYTHE QUIÑONES-MATEU LABORATORYPOSTDOCTORAL FELLOWSJan Weber, Ph.D.Hector Rangel, Ph.D.RESEARCH TECHNICIANSBikram Chakraborty, B.S.Patti Kaiser, M.S.GRADUATE STUDENTMichael Marotta, B.S.COLLABORATORSEric J. Arts, Ph.D. 1Esteban Domingo, Ph.D. 2Jose A. Este, Ph.D. 3Michael M. Lederman, M.D. 1Miguel A. Martinez, Ph.D. 3Robert H. Silverman, Ph.D. 4Vicente Soriano, M.D. 5Cheryl A. Stoddart, Ph.D. 6Zahra Toossi, M.D. 1Guido Vanham, M.D., Ph.D. 7Taolin Yi, Ph.D. 41Case Western Reserve Univ.,Cleveland, OH2Centro de Biologia Molecular“Severo Ochoa,” UniversidadAutonoma deMadrid, Spain3Fundacio irsiCaixa, Barcelona,Spain4Dept. of Cancer Biology, CCF5Instituto de Salud Carlos III,Madrid, Spain6Gladstone Inst. of Virology andImmunology, Univ. of Californiaat San Francisco7Inst. of Tropical Medicine,Antwerp, BelgiumQuiñones-Mateu, M.E., Albright, J.L., Mas, A., Soriano, V., and E.J. Arts (1998) Analysis of pol gene heterogeneity, viral quasispecies, and drugresistance in individuals infected with group O strains of human immunodeficiency virus type 1. J. Virol. 72:9002-9015.Quiñones-Mateu, M.E., Ball, S.C., Marozsan, A.J., Torre, V.S., Albright, J.L., Vanham, G., van der Groen, G., Colebunders, R.L., and E.J. Arts(2000) A dual infection/competition assay shows a correlation between ex vivo HIV-1 fitness and disease progression. J. Virol. 74:9222-9233.Quiñones-Mateu, M.E., Gao, Y., Ball, S.C., Marozsan, A., Abraha, A., and E.J. Arts (2002) In vitro intersubtype recombinants of human immunodeficiencyvirus type 1: comparison to recent and circulating in vivo recombinant forms. J. Virol. 76:9600-9613.Quiñones-Mateu, M.E., Tadele, M., Parera, M., Mas, A., Weber, J., Rangel, H.R., Chakraborty, B., Clotet, B., Domingo, E., Menendez-Arias, L., andM.A. Martinez (2002) Insertions in the reverse transcriptase increase both drug resistance and viral fitness in a human immunodeficiency virustype 1 isolate harboring the multi-nucleoside reverse transcriptase inhibitor resistance 69 insertion complex mutation. J. Virol. 76:10546-10552.Ball, S.C., Abraha, A., Collins, K.R., Marozsan, A.J., Baird, H., Quiñones-Mateu, M.E., Penn-Nicholson, A., Murray, M., Richard, N., Lobritz, M.,Zimmerman, P.A., Kawamura, T., Blauvelt, A., and E.J. Arts (2003) Comparing the ex vivo fitness of CCR5-tropic human immunodeficiency virustype 1 isolates of subtypes B and C. J. Virol. 77:1021-1038.115