Olga Latinovic - Academia.edu (original) (raw)

Papers by Olga Latinovic

The American Ceramic Society eBooks, Apr 3, 2012

This work addresses the microrheology of soft and biological materials such as poly(ethylene)oxid... more This work addresses the microrheology of soft and biological materials such as poly(ethylene)oxide solutions, type I collagen gels and endothelial cells using a novel oscillating optical tweezers technique.This advantageous technique is based on grabbing probe particles suspended in the media of interest with a tightly focused laser beam, measuring displacements and phase shifts of the particle’s motion from which to calculate the viscoelastic properties of homogeneous and inhomogeneous materials as the function of frequency and time. The validation of the optical tweezers microrheology is given in comparison between passive and active, forced oscillation approach. The local response of collagen gels was probed in order to characterize their viscoelastic and structural composition. This work expands the knowledge of these promising biological materials for use in tissue engineering as well as for opportunities in diagnostics and comparisons between normal and degenerated tissues in cancer research.The optical tweezers technique will be extended to use on endothelial cells to test the applicability of this probe as a non-invasive, effective rheometer in biomedical research.

Proceedings of the National Academy of Sciences

The human microbiota affects critical cellular functions, although the responsible mechanism(s) i... more The human microbiota affects critical cellular functions, although the responsible mechanism(s) is still poorly understood. In this regard, we previously showed that Mycoplasma fermentans DnaK, an HSP70 chaperone protein, hampers the activity of important cellular proteins responsible for DNA integrity. Here, we describe a novel DnaK knock-in mouse model generated in our laboratory to study the effect of M. fermentans DnaK expression in vivo. By using an array-based comparative genomic hybridization assay, we demonstrate that exposure to DnaK was associated with a higher number of DNA copy number variants (CNVs) indicative of unbalanced chromosomal alterations, together with reduced fertility and a high rate of fetal abnormalities. Consistent with their implication in genetic disorders, one of these CNVs caused a homozygous Grid2 deletion, resulting in an aberrant ataxic phenotype that recapitulates the extensive biallelic deletion in the Grid2 gene classified in humans as autosomal...

J AIDS HIV Treat 1.1, 2018

This is an open-access article distributed under the terms of the Creative Commons Attribution Li... more This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Springer eBooks, 2017

Ming-Tzo Wei, Olga Latinovic, Lawrence A. Hough, Yin-Quan Chen, H. Daniel Ou-Yang* and Arthur Chi... more Ming-Tzo Wei, Olga Latinovic, Lawrence A. Hough, Yin-Quan Chen, H. Daniel Ou-Yang* and Arthur Chiou* Bioengineering Program, Lehigh University, Bethlehem, PA, USA Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, USA Complex Assemblies of Soft Matter Lab, UMI 3254 CNRS/UPENN/Rhodia, Bristol, PA, USA Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan Department of Physics, Lehigh University, Bethlehem, PA, USA Biophotonics & Molecular Imaging Research Center, National Yang-Ming University, Taipei, Taiwan

Proceedings of the National Academy of Sciences, 2018

We isolated a strain of human mycoplasma that promotes lymphomagenesis in SCID mice, pointing to ... more We isolated a strain of human mycoplasma that promotes lymphomagenesis in SCID mice, pointing to a p53-dependent mechanism similar to lymphomagenesis in uninfected p53 −/− SCID mice. Additionally, mycoplasma infection in vitro reduces p53 activity. Immunoprecipitation of p53 in mycoplasma-infected cells identified several mycoplasma proteins, including DnaK, a member of the Hsp70 chaperon family. We focused on DnaK because of its ability to interact with proteins. We demonstrate that mycoplasma DnaK interacts with and reduces the activities of human proteins involved in critical cellular pathways, including DNA-PK and PARP1, which are required for efficient DNA repair, and binds to USP10 (a key p53 regulator), impairing p53-dependent anticancer functions. This also reduced the efficacy of anticancer drugs that depend on p53 to exert their effect. mycoplasma was detected early in the infected mice, but only low copy numbers of mycoplasma DnaK DNA sequences were found in some primary ...

Journal of Human Virology & Retrovirology, 2015

The CCR5 chemokine receptor plays a crucial role in HIV-1 infection, acting as the principal core... more The CCR5 chemokine receptor plays a crucial role in HIV-1 infection, acting as the principal coreceptor for viral entry and transmission, and as such offers an important potential therapeutic target. Studies have suggested that CCR5 surface density and its conformational changes subsequent to virions engagement are rate limiting for virus entry. Several small molecule antagonists have been developed that target the HIV-1 coreceptor CCR5. CCR5-tropic (R5) viral strains are by far the most prevalent and are the predominant transmitted types. Not all existing CCR5 blockers fully inhibit HIV-1 infection, suggesting a need for more potent reagents. This review will discuss some of the CCR5 blockers, their development, and existing or potential future clinical usage.

BioMed Research International, 2020

Recent comparisons between plant and animal viruses reveal many common principles that underlie h... more Recent comparisons between plant and animal viruses reveal many common principles that underlie how all viruses express their genetic material, amplify their genomes, and link virion assembly with replication. Cauliflower mosaic virus (CaMV) is not infectious for human beings. Here, we show that CaMV transactivator/viroplasmin protein (TAV) shares sequence similarity with and behaves like the human ribonuclease H1 (RNase H1) in reducing DNA/RNA hybrids detected with S9.6 antibody in HEK293T cells. We showed that TAV is clearly expressed in the cytosol and in the nuclei of transiently transfected human cells, similar to its distribution in plants. TAV also showed remarkable cytotoxic effects in U251 human glioma cells in vitro. These characteristics pave the way for future analysis on the use of the plant virus protein TAV, as an alternative to human RNAse H1 during gene therapy in human cells.

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Journal of Virology, 2019

The HIV-1 genome contains a gene expressed in the opposite, or antisense, direction to all other ... more The HIV-1 genome contains a gene expressed in the opposite, or antisense, direction to all other genes. The protein product of this antisense gene, called ASP, is poorly characterized, and its role in viral replication remains unknown. We provide evidence that the antisense protein, ASP, of HIV-1 is found within the cell nucleus in unstimulated cells. In addition, we show that after PMA treatment, ASP exits the nucleus and localizes on the cell membrane. Moreover, we demonstrate that ASP is present on the surfaces of viral particles. Altogether, our studies identify ASP as a new structural component of HIV-1 and show that ASP is an accessory protein that promotes viral replication. The presence of ASP on the surfaces of both infected cells and viral particles might be exploited therapeutically.

Frontiers in Microbiology, 2015

Shiga toxin-producing Escherichia coli (STEC) is a leading cause of childhood renal disease Hemol... more Shiga toxin-producing Escherichia coli (STEC) is a leading cause of childhood renal disease Hemolytic Uremic Syndrome (HUS). The involvement of renal cytokines and chemokines is suspected to play a critical role in disease progression. In current article, we tested the hypothesis that NKT cells are involved in Stx2-induced pathology in vivo. To address this hypothesis we compared Stx2 toxicity in WT and CD1 knockout (KO) mice. In CD1KO mice, which lack natural killer T (NKT) cells, Stx2-induced pathologies such as weight loss, renal failure, and death were delayed. In WT mice, Stx2-specific selective increase in urinary albumin occurs in later time points, and this was also delayed in NKT cell deficient mice. NKT cell-associated cytokines such as IL-2, IL-4, IFN-γ, and IL-17 were detected in kidney lysates of Stx2-injected WT mice with the peak around 36 h after Stx2 injection. In CD1KO, there was a delay in the kinetics, and increases in these cytokines were observed 60 h post Stx2 injection. These data suggest that NKT cells accelerate Stx2-induced pathology in mouse kidneys. To determine the mechanism by which NKT cells promote Stx2-associated disease, in vitro studies were performed using murine renal cells. We found that murine glomerular endothelial cells and podocytes express functional CD1d molecules and can present exogenous antigen to NKT cells. Moreover, we observed the direct interaction between Stx2 and the receptor Gb 3 on the surface of mouse renal cells by 3D STORM-TIRF which provides single molecule imaging. Collectively, these data suggest that Stx2 binds to Gb 3 on renal cells and leads to aberrant CD1d-mediated NKT cell activation. Therefore, strategies targeting NKT cells could have a significant impact on Stx2-associated renal pathology in STEC disease.

Journal of Translational Medicine, 2022

Background The chemokine receptor CCR5 is the major coreceptor for HIV-1 cell entry. We previousl... more Background The chemokine receptor CCR5 is the major coreceptor for HIV-1 cell entry. We previously observed that not all CCR5 mAbs reduce HIV-1 infection, suggesting that only some CCR5 populations are permissive for HIV-1 entry. This study aims to better understand the relevant conformational states of the cellular coreceptor, CCR5, involved in HIV entry. We hypothesized that CCR5 assumes multiple configurations during normal cycling on the plasma membrane, but only particular forms facilitate HIV-1 infection. Methods To this end, we quantified different CCR5 populations using six CCR5 monoclonal antibodies (mAbs) with different epitope specificities and visualized them with super-resolution microscopy. We quantified each surface CCR5 population before and after HIV-1 infection. Results Based on CCR5 conformational changes, down-modulation, and trafficking rates (internalization and recycling kinetics), we were able to distinguish among heterogeneous CCR5 populations and thus which...

This is an open access article distributed under the terms of the Creative Commons Attribution Li... more This is an open access article distributed under the terms of the Creative Commons Attribution License

AIDS Research and Human Retroviruses, 2019

Significant progress has been made in the diagnostics and treatment of AIDS since the discovery o... more Significant progress has been made in the diagnostics and treatment of AIDS since the discovery of the human immunodeficiency virus type 1 (HIV-1) in 1983. The remarkable effectiveness of combined antiretroviral therapy (cART) is evidenced by mortality reduction, control of peripheral blood viral load, and in a nearly normal quality of HIV patients' lives. Remaining obstacles in treatment and cure are drug toxicities and side effects, viral resistance, persistence of HIV-1 reservoirs on termination of cART treatment, the cost of lifelong antiretroviral therapy, and the stigma associated with taking antiretroviral drugs. As determined by plasma viral RNA and peripheral blood mononuclear cells (PBMC) proviral DNA, we show improved suppression of productive HIV infection in human CD34+ hematopoietic stem cell-engrafted NOD (nonobese diabetic)-SCID (severe combined immunodeficiency)-il2rg-/- (NSG) mice by combined treatment with cART and CCR5 targeting drugs, compared with cART alone, as well as an increased preservation of human CD4+ T cells (defined as CD45+ CD3+ CD4+ cells) and CD4+/CD8+ cell ratios in infected mice. The data also suggest a possible reduction in viral reservoirs. Our data confirm that this animal model is suitable for detection of productive HIV infection, replication, and establishment of viral reservoirs. The data also provide proof of principle for the utility of combining CCR5 targeting drugs, maraviroc and rapamycin, with traditional cART to improve control of viremia and reduce viral reservoirs. This study thus serves as a model for future HIV-1 studies that could lead to the clinical development of new generations of antiretroviral drugs.

Virology, 2011

R5 HIV-1 strains resistant to the CCR5 antagonist Maraviroc (MVC) can use drug-bound CCR5. We dem... more R5 HIV-1 strains resistant to the CCR5 antagonist Maraviroc (MVC) can use drug-bound CCR5. We demonstrate that MVC-resistant HIV-1 exhibits delayed kinetics of coreceptor engagement and fusion during drug-bound versus free CCR5 infection of cell lines. Antibodies directed against the second extracellular loop (ECL2) of CCR5 had greater antiviral activity against MVC-bound compared to MVC-free CCR5 infection. However, in PBMCs, only ECL2 CCR5 antibodies HGS004 and HGS101, but not 2D7, inhibited infection by MVC resistant HIV-1 more potently with MVC-bound than with free CCR5. In addition, HGS004 and HGS101, but not 2D7, restored the antiviral activity of MVC against resistant virus in PBMCs. In flow cytometric studies, CCR5 binding by the HGS mAbs, but not by 2D7, was increased when PBMCs were treated with MVC, suggesting MVC increases exposure of the relevant epitope. Thus, HGS004 and HGS101 have antiviral mechanisms distinct from 2D7 and could help overcome MVC resistance.

PLoS Pathogens, 2011

A large group of viruses rely on low pH to activate their fusion proteins that merge the viral en... more A large group of viruses rely on low pH to activate their fusion proteins that merge the viral envelope with an endosomal membrane, releasing the viral nucleocapsid. A critical barrier to understanding these events has been the lack of approaches to study virus-cell membrane fusion within acidic endosomes, the natural sites of virus nucleocapsid capsid entry into the cytosol. Here we have investigated these events using the highly tractable subgroup A avian sarcoma and leukosis virus envelope glycoprotein (EnvA)-TVA receptor system. Through labeling EnvA pseudotyped viruses with a pH-sensitive fluorescent marker, we imaged their entry into mildly acidic compartments. We found that cells expressing the transmembrane receptor (TVA950) internalized the virus much faster than those expressing the GPIanchored receptor isoform (TVA800). Surprisingly, TVA800 did not accelerate virus uptake compared to cells lacking the receptor. Subsequent steps of virus entry were visualized by incorporating a small viral content marker that was released into the cytosol as a result of fusion. EnvA-dependent fusion with TVA800-expressing cells occurred shortly after endocytosis and delivery into acidic endosomes, whereas fusion of viruses internalized through TVA950 was delayed. In the latter case, a relatively stable hemifusion-like intermediate preceded the fusion pore opening. The apparent size and stability of nascent fusion pores depended on the TVA isoforms and their expression levels, with TVA950 supporting more robust pores and a higher efficiency of infection compared to TVA800. These results demonstrate that surface receptor density and the intracellular trafficking pathway used are important determinants of efficient EnvA-mediated membrane fusion, and suggest that early fusion intermediates play a critical role in establishing low pH-dependent virus entry from within acidic endosomes.

Antiviral Research, 2009

Maraviroc, the only CCR5 antagonist HIV inhibitor currently approved, has potent antiviral activi... more Maraviroc, the only CCR5 antagonist HIV inhibitor currently approved, has potent antiviral activity in treatment-experienced individuals infected with CCR5-using HIV-1 (R5 HIV-1). However, recent data from the MOTIVATE trials indicate that R5 HIV-1 can develop resistance to Maraviroc, underscoring the need for additional CCR5 antagonists. The CCR5 antagonist aplaviroc (APL) is active against Maraviroc-resistant viral strains but its clinical development has ended because of dose-related toxicity. Here we demonstrate that reduction of CCR5 density (receptors/cell) with the immunomodulatory drug rapamycin (RAPA) enhances the antiviral activity of APL, allowing lower, non-toxic effective doses. In the presence of RAPA, the concentration of APL required for 90% inhibition of R5 HIV-1 in primary CD4 lymphocytes was reduced by as much as 25-fold. We conclude that low doses of RAPA may reduce the anti-HIV effective dose of APL-derivatives currently in development and thus minimize their potential toxicity. Combinations of RAPA and CCR5 antagonists could provide an effective means to control drug-resistant R5 HIV in patients, most notably those infected with Maraviroc-resistant viruses.

Antimicrobial Agents and Chemotherapy, 2007

The CCR5 chemokine receptor plays a pivotal role in human immunodeficiency virus type 1 (HIV-1) i... more The CCR5 chemokine receptor plays a pivotal role in human immunodeficiency virus type 1 (HIV-1) infection. Several studies have suggested that CCR5 density levels in individuals are rate limiting for infection. In addition, CCR5 density levels influence the antiviral activity of the HIV-1 fusion inhibitor enfuvirtide (T-20) against R5 strains. In the present study we demonstrate that rapamycin (RAPA), a drug approved for the treatment of renal transplantation rejection, reduces CCR5 density levels on CD4 T cells and inhibits R5 HIV-1 replication. In addition, RAPA increased the antiviral activity of T-20 against R5 strains of the virus in a cell-cell fusion assay and as shown by quantification of early products of viral reverse transcription. Median-effect analysis of drug interaction between RAPA and T-20 in infectivity assays using donor peripheral blood mononuclear cells demonstrated that the RAPA-T-20 combination is synergistic against R5 strains of HIV-1 and this synergy transl...

AIDS, 2011

CCR5 blockers inhibit CCR5-tropic (R5) HIV-1, including strains resistant to other antiretroviral... more CCR5 blockers inhibit CCR5-tropic (R5) HIV-1, including strains resistant to other antiretrovirals. We demonstrate that the CCR5 antibody HGS004 and the CCR5 antagonist Maraviroc have potent antiviral synergy against R5 HIV-1, translating into dose reductions of >10-fold for Maraviroc and >150-fold for HGS004. These data, together with the high barrier of resistance to HGS004, suggest that combinations of Maraviroc and HGS004 could provide effective preventive and therapeutic strategies against R5 HIV-1.