Ambrose Laboratory
It is estimated that over 30 million people worldwide are infected with HIV-1. Although HIV-1 can be effectively suppressed with current antiretroviral therapy, it is not eradicated from the body. Most HIV+ individuals who stop suppressive therapy have a rapid rebound in plasma viremia, which is most likely due to the persistence of the virus in long-lived reservoirs. These reservoirs may be maintained by low level, ongoing HIV-1 replication in tissues that is not effectively blocked by currently used antiretroviral regimens. However, the anatomical locations and cell types for these persisting viral reservoirs in infected hosts have not been identified.
The Ambrose laboratory uses in vivo and in vitro models to study viral persistence. The RT-SHIVmne macaque model is useful in the identification and characterization of viral persistence during suppressive therapy and the identification of these long-lived reservoirs, which cannot be performed easily in humans. Understanding viral reservoirs should provide valuable information on the location of persisting virus in the body and will make it easier to target antiretroviral methods to the appropriate tissues and cells to attempt to eradicate HIV-1 from infected individuals.
The development of drug resistant HIV-1 is a major problem and can arise with all currently used treatment regimens. Despite this, the origin, evolution, and persistence of drug resistance in blood and different tissue compartments are not well understood. We are studying viral diversity and variability, particularly drug resistance-conferring mutations, in different tissues from infected macaques before, during, and after therapy. This may identify the nature and dynamic properties of persistent viral reservoirs in ways that are not possible to perform in people. Understanding how these reservoirs arise and are established by both wild-type and drug resistant viral variants may help determine better strategies for treating HIV-infected individuals, particularly those harboring and potentially transmitting drug resistant virus.
Macrophages have been suggested to contribute to persisting viral reservoirs in vivo. However, less is known about HIV-1 infection of these cells, although it appears to differ from the T lymphocyte infection pathway in many respects. Also, the role of host cell proteins in the HIV-1 lifecycle is poorly understood and is the topic of much investigation in the field. The Ambrose laboratory is investigating the differences between HIV-1 infection of macrophages vs. CD4+ T cells, both critical cell types infected in the host. We hope by elucidating these differences, we can eventually exploit these pathways with novel antiretroviral drug candidates.
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Zandrea Ambrose, Ph.D.
Assistant Professor of Medicine
ambrosez@dom.pitt.edu |
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Tamera Kirkland
Research Technician
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Doi Laboratory
Mission Statement: To investigate novel mechanisms of antimicrobial resistance in Gram-negative pathogens.
Infections due to antimicrobial resistant Gram-negative pathogens continue to pose substantial threat to human well-being. Once thought to be nosocomial, these pathogens are now emerging among non-nosocomial patients including those purely from the community. We are currently conducting several research projects, as outlined below, to elucidate how they acquire resistance to various classes of antimicrobials and what features distinguish them from others.
Epidemiology of extended-spectrum beta-lactamases (ESBLs) and AmpC-type beta-lactamases in Escherichia coli strains from the community and hospitals.
Genetic and kinetic characterization of novel AmpC-type beta-lactamases with unique substrate profiles.
Investigation of 16S ribosomal RNA methylase-mediated aminoglycoside resistance.
Epidemiology of antimicrobial resistance genes in Acinetobacter baumannii.
Characterization of mechanisms that lead to colistin resistance.
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Yohei Doi, Ph.D.
Assistant Professor of Medicine
@dom.pitt.edu |
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Ghedin Laboratory
The focus of our laboratory is on defining genomic characteristics of emerging pathogens. Our research is multidisciplinary and draws upon the tools of genomics, molecular virology, and computational biology. Projects include the study of RNA virus evolution and emergence, the discovery of new retroelements in parasite genomes, and the characterization of endosymbiotic host-parasite interactions.
Please visit our website to read more...
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Harrison Laboratory
The mission of the Public Heath Infectious Disease Laboratory (PHIDL), a component of the Infectious Diseases Epidemiology Research Unit, is to improve and conduct molecular epidemiologic investigation of nosocomial and community acquired bacterial infections. This includes the development of automated, objective and highly discriminatory genotyping methods and research on the genetic basis of disease pathogenesis in several important nosocomial and community-acquired pathogens. Ongoing PHIDL projects include: 1) investigation of Clostridium difficile transmission within hospitals by multi-locus variable number tandem repeat analysis (MLVA) and molecular characterization of toxin production from an emergent hypervirulent clone; 2) molecular surveillance of Neisseria meningitidis and genetic characterization of antigenic variants causing invasive meningococcal disease; 3) molecular epidemiologic investigation of integron-associated multi-drug resistant non-typhoidal Salmonella. The laboratory employs a variety of molecular methods including pulsed field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), and MLVA to determine the genetic relationships among bacteria and identify potential outbreaks. In this regard, PHIDL supports the UPMC Infection Control Unit to perform molecular genotyping of potential hospital acquired infections. In addition, PHIDL provides training in molecular epidemiology to masters and doctoral students, infectious diseases fellows, and visiting international scientists.
To visit Dr. Harrison's biography page, please click here. Laboratory personnel descriptions are included below.
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Mellors Laboratory
The goal of our research is to find the most effective ways to prevent and treat HIV-1 infection. This includes the discovery, preclinical and clinical evaluation of antiretroviral compounds for prevention and treatment of HIV-1 to help control the global AIDS epidemic. Drug resistance has developed to most antiretrovirals and can lead to treatment failure, clinical disease progression and death despite treatment. Drug resistance may also reduce the effectiveness of antiretrovirals used for HIV-1 prevention. Effective strategies are needed to prevent the emergence of drug-resistant HIV and to treat patients in whom drug-resistant virus is present. Our laboratory characterizes drug resistance mechanisms at the clinical, virologic, biochemical and structural level and applies this information to the design of new antiretrovirals and treatment strategies to minimize the emergence of drug resistance. To accomplish this, our laboratory is comprised of a talented team of research specialists, doctoral students, and postdoctoral PhD and MD fellows, and collaborates closely with top scientist within the Division (Sluis-Cremer, Ambrose and Parikh Laboratories) and at other institutions.
To visit Dr. Mellors' biography page, please click here. Laboratory personnel descriptions are included below.
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Nguyen-Clancy Laboratory
Lab description coming soon....
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Minh-Hong Nguyen, MD
Assistant Professor of Medicine
@dom.pitt.edu |
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Paterson Laboratory
Mission Statement: To link epidemiology of infections with Gram negative bacilli with molecular epidemiology and mechanisms of resistance.
Our research focuses on the mechanisms of resistance and molecular epidemiology of bacteria resistant to multiple antibiotics. This research is intrinsically linked to clinical epidemiologic studies on antibiotic resistance. Traditionally, epidemiologic studies have sought clinical risk factors for infections with antibiotic resistant organisms. However, such an approach neglects the potential clonality of resistant organisms or the fact that resistance to an antibiotic may be mediated by different mechanisms in different patients. Therefore, organisms collected during clinical studies are subjected in our laboratory to pulsed field gel electrophoresis (PFGE) and investigation into the mechanisms of antibiotic resistance.
Investigations performed in our laboratory have included antibiotic susceptibility testing, pulsed field gel electrophoresis, examination of outer membrane proteins, PCR for detection of genes encoding beta-lactamases and plasmid analysis.
We have a long-standing interest in extended-spectrum beta-lactamases (ESBLs) but also have a substantial interest in KPC-producing and MBL-producing organisms and in antibiotic resistance in Acinetobacter baumannii. We have a particular interest in utility of colistin for multiresistant Gram negative infections.
The laboratory also serves as a resource for clinical studies such as those studying infections in transplant recipients and those studying pharmacodynamics of antimicrobials such as colistin.
To visit Dr. Paterson's biography page, please click here. Laboratory personnel descriptions are included below.
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David Paterson, MD, PhD
Assistant Professor of Medicine
david.antibiotics@gmail.com |
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Jennifer Adams-Haduch
Lab Manager |
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Hanna Sidjabat, PhD
Post-doctoral Scholar |
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Parikh Laboratory
Urvi M. Parikh, Ph.D. is an Assistant Professor of Medicine in the Division of Infectious Diseases and Associate Director of the Microbicide Trials Network (MTN) Virology Core. Her work in the HIV field began in 1998 at Roche Diagnostics, in technical support and manufacturing of Amplicor Monitor HIV, HCV and CT/NG viral load kits. Her graduate work with Dr. John Mellors focused on elucidating mechanisms of drug resistance to nucleoside reverse transcriptase inhibitors, particularly the tenofovir-resistance mutation K65R. She was an NIH fellow at the National Institute of Infectious Diseases in Tokyo studying non-B HIV subtypes, and a visiting scholar at the University of Oxford, UK, studying HIV-1 reverse transcriptase structure. At the US Centers for Disease Control and Prevention (CDC), Dr. Parikh formulated and evaluated combinations of antiretroviral agents for potential use as topical gels, and conducted toxicity and efficacy studies in a pigtail macaque model. She also worked at CDC’s Botswana field site, supporting the laboratory in its transition to a new HIV chemoprophylaxis trial. She recently joined the MTN in April 2008. Her research with the MTN will include validation of HIV-1 infection endpoints in women who seroconvert during microbicide trials, assessment of possible effects of microbicides on HIV-1 natural history, and evaluation of drug resistance in breakthrough infections in trial participants.
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Sluis-Cremer Laboratory
Our research focuses on:
Nonnucleoside reverse transcriptase inhibitor (NNRTI) induced conformational changes in HIV-1 reverse transcriptase (RT). Recent studies have shown that NNRTI can modulate the inter-subunit interactions between the 66kDa and 51kDa polypeptides of RT. The molecular mechanisms by which this occurs, and the impact that this has on RT enzyme functioning is not known. In light of this, the specific aims of this project are to: (1) determine the mechanisms by which NNRTI modulate the inter-subunit interactions and intra-subunit conformational changes of HIV-1 RT; and (2) define the molecular interactions in the HIV-1 RT dimer interface and to evaluate the consequences of altering the intrinsic dimeric stability on enzymatic activity.
HIV-1 RT dimerization as an antiviral target. HIV-1 reverse transcriptase is a heterodimeric enzyme consisting of a 66-kDa subunit (p66) and a p66-derived 51-kDa subunit (p51). The DNA polymerase and ribonuclease H (RNase H) activities of the enzyme are entirely dependent on the heterodimeric structure of the enzyme, suggesting that inhibition of the subunit-subunit assembly of RT provides an alternative target for HIV-1 inhibition. The specific aims of this project are: (1) to develop, optimize and validate an HTS assay for RT dimerization; and (2) to screen chemical libraries to identify compounds that inhibit RT dimerization.
Molecular mechanisms of HIV-1 RT resistance to nucleoside reverse transcriptase inhibitors (NRTI): Although NRTI therapy is initially quite effective in reducing the viral load in HIV-1 infected individuals, the viral burden inevitably rebounds despite continued therapy, due to the appearance of drug-resistant strains of HIV. The primary objectives of this project are to understand the molecular (phenotypic) mechanisms by which drug-resistant HIV-1 RT provides resistance to NRTI such as 3?-azido-3?deoxythymidine (AZT) by utilizing appropriate in vitro biochemical models and molecular modeling.
To visit Dr. Sluis-Cremer's biography page, please click here. Laboratory personnel descriptions are included below.
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Chihwei Tina Sheen
Research Specialist III |
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Shannon Zelina
Research Specialist |
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