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Papers by Udaykumar Ranga

The stochastic fluctuations in gene expression emanating from HIV-1 long terminal repeat (LTR), a... more The stochastic fluctuations in gene expression emanating from HIV-1 long terminal repeat (LTR), amplified by the Tat positive feedback circuit, determine the choice between viral infection fates: active transcription (ON) or transcriptional silence (OFF). The emergence of several transcription factor binding site (TFBS) variant strains in HIV-1 subtype C (HIV-1C), especially those containing the duplication of NF-κB motif, mandates the evaluation of the effect of enhanced transcriptional strength on gene expression noise and its influence on viral fate-selection switch. Using a panel of subgenomic LTR-variant strains containing varying copy numbers of the NF-κB motif (ranging from 0 to 4), we employed flow cytometry, mRNA quantification, and pharmacological perturbations to demonstrate an inverse correlation between promoter strength and gene expression noise in Jurkat T-cells and primary CD4+ T-cells. The inverse correlation is consistent in clonal cell populations, at constant int...

Frontiers in Neuroscience

BackgroundCommonly used opioids, such as morphine have been implicated in augmented SIV/HIV persi... more BackgroundCommonly used opioids, such as morphine have been implicated in augmented SIV/HIV persistence within the central nervous system (CNS). However, the extent of myeloid cell polarization and viral persistence in different brain regions remains unclear. Additionally, the additive effects of morphine on SIV/HIV dysregulation of gut-brain crosstalk remain underexplored. Therefore, studies focused on understanding how drugs of abuse such as morphine affect immune dynamics, viral persistence and gut-brain interrelationships are warranted.Materials and methodsFor a total of 9 weeks, rhesus macaques were ramped-up, and twice daily injections of either morphine (n = 4) or saline (n = 4) administered. This was later followed with infection with SHIVAD8EO variants. At necropsy, mononuclear cells were isolated from diverse brain [frontal lobe, cerebellum, medulla, putamen, hippocampus (HIP) and subventricular zone (SVZ)] and gut [lamina propria (LP) and muscularis (MUSC) of ascending co...

Human immunodeficiency virus type 1 (HIV-1)-associated dementia (HAD) is correlated with increase... more Human immunodeficiency virus type 1 (HIV-1)-associated dementia (HAD) is correlated with increased monocyte migration to the brain, and the incidence of HAD among otherwise asymptomatic subjects appears to be lower in India than in the United States and Europe (1 to 2% versus 15 to 30%). Because of the genetic differences between HIV-1 strains circulating in these regions, we sought to identify viral determinants associated with this difference. We targeted Tat protein for these studies in view of its association with monocyte chemotactic function. Analyses of Tat sequences representing nine subtypes revealed that at least six amino acid residues are differentially conserved in subtype C Tat (C-Tat). Of these, cysteine (at position 31) was highly (>99%) conserved in non-subtype C viruses and more than 90% of subtype C viruses encoded a serine. We hypothesized a compromised chemotactic function of C-Tat due to the disruption of CC motif and tested it with the wild type C-Tat (CS) and its two isogenic variants (CC and SC) derived by site-directed mutagenesis. We found that the CS natural variant was defective for monocyte chemotactic activity without a loss in the transactivation property. While the CC mutant is functionally competent for both the functions, in contrast, the SC mutant was defective in both. Therefore, the loss of the C-Tat chemotactic property may underlie the reduced incidence of HAD; although not presenting conclusive evidence, this study provides the first evidence for a potential epidemiologic phenomenon associated with biological differences in the subtype C viruses.

VirusDisease, 2021

Aerosol particles can spread respiratory infections, especially those caused by viruses; however,... more Aerosol particles can spread respiratory infections, especially those caused by viruses; however, the perceived threat is small for many technical reasons, as identified in this article. Under controlled conditions, aerosol particles can travel up to a distance of 28 feet (or 8 m); however, such aerosol particles are less likely to have sufficient quantities of viable viruses to spread infection. Additionally, nearly all the experimental models examined the behavior of the aerosols only in confined spaces, not in open areas; these findings, therefore, cannot be considered generally applicable. In the absence of scientific information and education, only misconceptions, unfounded fears, and unsubstantiated myths will prevail. Given that an effective vaccine and drugs are still not available, prevention remains the only option of protection against SARS-CoV-2, the new coronavirus. Wearing a mask is not only necessary but also critical to reduce the probability of viral spread by contact (fomite), not aerosol, transmission. Keywords Virus Á Coronavirus Á SARS-CoV-2 Á COVID-19 Á Aerosol particle Á Facemask VirusDis.

Frontiers in Immunology, 2020

Recent spread of the promoter variant (4-κB) Human immunodeficiency virus-1 clade C (HIV-1C) stra... more Recent spread of the promoter variant (4-κB) Human immunodeficiency virus-1 clade C (HIV-1C) strain is attributed to duplication of the Nuclear Factor Kappa B (NF-κB) binding sites and potential increased heroin consumption in India. To study the underlying biology of 4-κB HIV-1C in rhesus macaques, we engineered a promoter-chimera variant (4NF-κB) Simian Human Immunodeficiency Virus (SHIV) by substituting the HIV-1C Long Terminal Repeat (LTR) region consisting of 4 NF-κB and 3 Sp-1 sites with the corresponding segment in the LTR of SHIV AD8EO. The wild-type (3NF-κB) promoter-chimera SHIV was generated by inactivating the 5 ′ proximal NF-κB binding site in SHIV 4NF-κB. CD8-depleted rhesus macaque PBMCs (RM-PBMCs) were infected with the promoter-chimera and AD8EO SHIVs to determine the effects of opioid-exposure on inflammation, NF-κB activation, neurotoxicity in neuronal cells and viral replication. Morphine-exposure of RM-PBMCs infected with SHIVs 4NF-κB, 3NF-κB, and AD8EO altered cellular transcript levels of monocyte chemoattractant protein 1, interleukin 6, interleukin 1β, and Tumor Necrosis Factor α. Of note, divergent alteration of the cytokine transcript levels was observed with these promoter-chimera wild-type and variant SHIVs. NF-κB activation was observed during infection of all three SHIVs with morphine-exposure. Finally, we observed that SHIV AD8EO infection and exposure to both morphine and naloxone had the greatest impact on the neurotoxicity. The promoter-chimera SHIV 4NF-κB and SHIV 3NF-κB did not have a similar effect on neurotoxicity as compared to SHIV AD8EO. All SHIVs replicated efficiently at comparable levels in RM-PBMCs and morphine-exposure did not alter viral replication kinetics. Future in vivo studies in rhesus macaques will provide greater understanding of 4-κB HIV-1C viral immunopathogenesis and onset of disease in the central nervous system during morphine-exposure.

Pediatric Exercise Science, 2019

Aim: To compare the markers of inflammation and immune activation in virally suppressed HIV-infec... more Aim: To compare the markers of inflammation and immune activation in virally suppressed HIV-infected children on antiretroviral therapy, who practiced regular structured exercise comprising running and yoga to those who did not over a 2-year period. Methods: This retrospective cohort study included 72 children aged 8 to 16 years divided into 2 groups, exercisers (n = 36) and the nonexercisers (n = 36) based on their intentional physical activity. The analyses were carried out at baseline and after 2 years (Y2) for the soluble biomarkers of inflammation and immune activation (tumor necrosis factor alpha, interleukin-6, interleukin-10, interferon gamma, sCD14, and sCD163). In addition, cell-associated biomarker (CD38), lipopolysaccharides, and the gene expression of interleukin-2 and brain-derived neurotrophic factor were also measured at Y2. Results: Reduction in levels of sCD14 (effect size [ES], −0.6; 95% confidence interval [CI], −1.08 to −0.14), tumor necrosis factor alpha (ES, −...

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... Udaykumar Ranga uday@jncasr.ac.in Jawaharlal Nehru Center for Advanced Scientific Research Ja... more ... Udaykumar Ranga uday@jncasr.ac.in Jawaharlal Nehru Center for Advanced Scientific Research Jakkur, Bangalore, India Abstract ... Dk}, the problem is to find the codon sequence, SC = c1c2c3…………cJ, where each ci ∈ C(ai), 1≤ i ≤ J, and the DNA sequence, SD ...

Journal of Medical Virology, 2019

Using cell-associated DNA and cell-free RNA of HIV-1, we investigated the role of drugresistant v... more Using cell-associated DNA and cell-free RNA of HIV-1, we investigated the role of drugresistant viral variants that emerged during early antiretroviral therapy (ART) in determining virological outcome. This case-control study compared virologic non-responder children (two viral loads ≥200 copies/ml within two years of ART) and responder children (two VLs <200 copies/ml after six months of ART) infected with HIV-1 initiated on nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART. The partial reverse transcriptase gene of HIV-1 in cell-associated DNA was genotyped using next-generation

Background: India has the third largest HIV-1 epidemic with 2.4 million infected individuals. Mol... more Background: India has the third largest HIV-1 epidemic with 2.4 million infected individuals. Molecular epidemiological analysis has identified the predominance of HIV-1 subtype C (HIV-1C). However, the previous reports have been limited by sample size, and uneven geographical distribution. The introduction of HIV-1C in India remains uncertain due to this lack of structured studies. To fill the gap, we characterised the distribution pattern of HIV-1 subtypes in India based on data collection from nationwide clinical cohorts between 2007 and 2011. We also reconstructed the time to the most recent common ancestor (tMRCA) of the predominant HIV-1C strains. Methodology/Principal Findings: Blood samples were collected from 168 HIV-1 seropositive subjects from 7 different states. HIV-1 subtypes were determined using two or three genes, gag, pol, and env using several methods. Bayesian

Tat/Rev Induced Limiting Dilution Assay (TILDA) is instrumental in estimating the size of latent ... more Tat/Rev Induced Limiting Dilution Assay (TILDA) is instrumental in estimating the size of latent reservoirs of HIV-1. Here, we report an optimized TILDA containing a broader detection range compared to the reported methods and high sensitivity. Giving priority to sequence conservation, we positioned the two forward primers and the probe in exon-1 of HIV-1. The reverse primers are positioned in highly conserved regions of exon-7. The optimized TILDA detected eight molecular clones belonging to five major genetic subtypes of HIV-1 with a comparable detection sensitivity. Using the optimized assay, we show that only a minor proportion of CD4+ T cells of primary clinical samples can spontaneously generate multiply spliced viral transcripts. A significantly larger proportion of the cells produced viral transcripts following activation. The optimized TILDA is suitable to characterize HIV-1 latent reservoirs and the therapeutic strategies intended to target the reservoir size.

Frontiers in Immunology, 2020

The natural cysteine to serine variation at position 31 of Tat in HIV-1C disrupts the dicysteine ... more The natural cysteine to serine variation at position 31 of Tat in HIV-1C disrupts the dicysteine motif attenuating the chemokine function of Tat. We ask if there exists a trade-off in terms of a gain of function for HIV-1C Tat due to this natural variation. We constructed two Tat-expression vectors encoding Tat proteins discordant for the serine 31 residue (CS-Tat vs. CC-Tat), expressed the proteins in Jurkat cells under doxycycline control, and performed the whole transcriptome analysis to compare the early events of Tat-induced host gene expression. Our analysis delineated a significant enrichment of pathways and gene ontologies associated with the angiogenic signaling events in CS-Tat stable cells. Subsequently, we validated and compared angiogenic signaling events induced by CS- vs. CC-Tat using human umbilical vein endothelial cells (HUVEC) and the human cerebral microvascular endothelial cell line (hCMEC/D3). CS-Tat significantly enhanced the production of CCL2 from HUVEC and ...

In a multicentric, observational, investigator-blinded, and longitudinal clinical study of 764 AR... more In a multicentric, observational, investigator-blinded, and longitudinal clinical study of 764 ART-naïve subjects, we identified nine different promoter-variant strains of HIV-1 subtype C (HIV-1C) emerging in the Indian population, with some of these variants being reported for the first time. Unlike several previous studies, our work here focuses on the evolving viral regulatory elements, not coding sequences. The emerging viral strains contain additional copies of the existing transcription factor binding sites (TFBS), including TCF-1α/LEF-1, RBEIII, AP-1, and NF-κB, created by sequence duplication. The additional TFBS are genetically diverse and may blur the distinction between the modulatory region of the promoter and the viral enhancer. In a follow-up analysis, we found trends, but not significant associations between any specific variant promoter and prognostic markers, probably because the emerging viral strains might not have established mono infections yet. Illumina sequenc...

The magnitude of transcription factor binding site variation emerging in HIV-1C, especially the a... more The magnitude of transcription factor binding site variation emerging in HIV-1C, especially the addition of NF-κB motifs by sequence duplication, makes the examination of transcriptional silence challenging. How can HIV-1 establish and maintain latency despite having a strong LTR? We constructed panels of sub-genomic reporter viral vectors with varying copy numbers of NF-κB motifs (0 to 4 copies) and examined the profile of latency establishment in Jurkat cells. We found surprisingly that the stronger the viral promoter, the faster the latency establishment. Importantly, at the time of commitment to latency and subsequent points, Tat levels in the cell were not limiting. Using highly sensitive strategies, we demonstrate the presence of Tat in the latent cell, recruited to the latent LTR. Our data allude, for the first time, to Tat establishing a negative feedback loop during the late phases of viral infection, leading to the rapid silencing of the viral promoter.ImportanceOver the p...

The Journal of biological chemistry, Jan 17, 2018

HIV-1 subtype C (HIV-1C) may duplicate longer amino acid stretches in the p6 Gag protein, leading... more HIV-1 subtype C (HIV-1C) may duplicate longer amino acid stretches in the p6 Gag protein, leading to the creation of an additional Pro-Thr/Ser-Ala-Pro (PTAP) motif necessary for viral packaging. However, the biological significance of a duplication of the PTAP motif for HIV-1 replication and pathogenesis has not been experimentally validated. In a longitudinal study of two different clinical cohorts of select HIV-1 seropositive, drug-naive individuals from India, we found that 8 of 50 of these individuals harbored a mixed infection of viral strains discordant for the PTAP duplication. Conventional and next-generation sequencing of six primary viral quasispecies at multiple time points disclosed that in a mixed infection, the viral strains containing the PTAP duplication dominated the infection. The dominance of the double-PTAP viral strains over a genetically similar single-PTAP viral clone was confirmed in viral proliferation and pairwise competition assays. Of note, in the proximi...

Retrovirology

Background We observe the emergence of several promoter-variant viral strains in India during rec... more Background We observe the emergence of several promoter-variant viral strains in India during recent years. The variant viral promoters contain additional copies of transcription factor binding sites present in the viral modulatory region or enhancer, including RBEIII, LEF-1, Ap-1 and/or NF-κB. These sites are crucial for governing viral gene expression and latency. Here, we infer that one variant viral promoter R2N3-LTR containing two copies of RBF-2 binding sites (an RBEIII site duplication) and three copies of NF-κB motifs may demonstrate low levels of gene expression noise as compared to the canonical RN3-LTR or a different variant R2N4-LTR (a duplication of an RBEIII site and an NF-κB motif). To demonstrate this, we constructed a panel of sub-genomic viral vectors of promoter-variant LTRs co-expressing two reporter proteins (mScarlet and Gaussia luciferase) under the dual-control of Tat and Rev. We established stable pools of CEM.NKR-CCR5 cells (CEM-CCR5RL reporter cells) and e...

Scientific Reports, 2016

The delivery of plasmid DNA to the skin can target distinct subsets of dermal dendritic cells to ... more The delivery of plasmid DNA to the skin can target distinct subsets of dermal dendritic cells to confer a superior immune response. The needle-free immunization technology offers a reliable, safe and efficient means to administer intradermal (ID) injections. We report here that the ID injection of DNA vectors using an NF device (NF-ID) elicits a superior cell-mediated immune response, at much lesser DNA dosage, comparable in magnitude to the traditional intramuscular immunization. However, the humoral response is significantly impaired, possibly at the stage of B cell isotype switching. We found that the NF-ID administration deposits the DNA primarily on the epidermis resulting in a rapid loss of the DNA as well as the synthesized antigen due to the faster regeneration rate of the skin layers. Therefore, despite the immune-rich nature of the skin, the NF-ID immunization of DNA vectors may be limited by the impaired humoral response. Additional booster injections are required to augment the antibody response. As an alternative and a viable solution, we rescued the IgG response by coadministration of a Toll-like receptor 9 agonist, among other adjuvants examined. Our work has important implication for the optimization of the emerging needle-free technology for ID immunization.

BMC infectious diseases, Jan 24, 2017

HIV-1 subtype C demonstrates several biological properties distinct from other viral subtypes. On... more HIV-1 subtype C demonstrates several biological properties distinct from other viral subtypes. One such variation is the duplication of PTAP motif in p6 Gag. PTAP motif is a key player in viral budding. Here, we studied the prevalence of PTAP motif duplication in subtype C viral strains in a longitudinal study. In a prospective follow-up study, 65 HIV-1 seropositive drug-naive subjects were monitored in two different clinical cohorts of India for 2 years with repeated sampling at 6-month intervals. The viral RNA was extracted from plasma, the gag segment was amplified and sequenced. From a subset of viral isolates the sequences of pol, env and LTR were sequenced. Using HIV-1 gag amino acid sequences available from public databases and additional sequences derived from the Indian and South-African cohorts, we examined the nature of PTAP motif duplication in subtype C. In 16% (8 of 50) of the primary viral strains of India, we identified a sequence duplication of the PTAP motif in Gag...

The stochastic fluctuations in gene expression emanating from HIV-1 long terminal repeat (LTR), a... more The stochastic fluctuations in gene expression emanating from HIV-1 long terminal repeat (LTR), amplified by the Tat positive feedback circuit, determine the choice between viral infection fates: active transcription (ON) or transcriptional silence (OFF). The emergence of several transcription factor binding site (TFBS) variant strains in HIV-1 subtype C (HIV-1C), especially those containing the duplication of NF-κB motif, mandates the evaluation of the effect of enhanced transcriptional strength on gene expression noise and its influence on viral fate-selection switch. Using a panel of subgenomic LTR-variant strains containing varying copy numbers of the NF-κB motif (ranging from 0 to 4), we employed flow cytometry, mRNA quantification, and pharmacological perturbations to demonstrate an inverse correlation between promoter strength and gene expression noise in Jurkat T-cells and primary CD4+ T-cells. The inverse correlation is consistent in clonal cell populations, at constant int...

Frontiers in Neuroscience

BackgroundCommonly used opioids, such as morphine have been implicated in augmented SIV/HIV persi... more BackgroundCommonly used opioids, such as morphine have been implicated in augmented SIV/HIV persistence within the central nervous system (CNS). However, the extent of myeloid cell polarization and viral persistence in different brain regions remains unclear. Additionally, the additive effects of morphine on SIV/HIV dysregulation of gut-brain crosstalk remain underexplored. Therefore, studies focused on understanding how drugs of abuse such as morphine affect immune dynamics, viral persistence and gut-brain interrelationships are warranted.Materials and methodsFor a total of 9 weeks, rhesus macaques were ramped-up, and twice daily injections of either morphine (n = 4) or saline (n = 4) administered. This was later followed with infection with SHIVAD8EO variants. At necropsy, mononuclear cells were isolated from diverse brain [frontal lobe, cerebellum, medulla, putamen, hippocampus (HIP) and subventricular zone (SVZ)] and gut [lamina propria (LP) and muscularis (MUSC) of ascending co...

Human immunodeficiency virus type 1 (HIV-1)-associated dementia (HAD) is correlated with increase... more Human immunodeficiency virus type 1 (HIV-1)-associated dementia (HAD) is correlated with increased monocyte migration to the brain, and the incidence of HAD among otherwise asymptomatic subjects appears to be lower in India than in the United States and Europe (1 to 2% versus 15 to 30%). Because of the genetic differences between HIV-1 strains circulating in these regions, we sought to identify viral determinants associated with this difference. We targeted Tat protein for these studies in view of its association with monocyte chemotactic function. Analyses of Tat sequences representing nine subtypes revealed that at least six amino acid residues are differentially conserved in subtype C Tat (C-Tat). Of these, cysteine (at position 31) was highly (>99%) conserved in non-subtype C viruses and more than 90% of subtype C viruses encoded a serine. We hypothesized a compromised chemotactic function of C-Tat due to the disruption of CC motif and tested it with the wild type C-Tat (CS) and its two isogenic variants (CC and SC) derived by site-directed mutagenesis. We found that the CS natural variant was defective for monocyte chemotactic activity without a loss in the transactivation property. While the CC mutant is functionally competent for both the functions, in contrast, the SC mutant was defective in both. Therefore, the loss of the C-Tat chemotactic property may underlie the reduced incidence of HAD; although not presenting conclusive evidence, this study provides the first evidence for a potential epidemiologic phenomenon associated with biological differences in the subtype C viruses.

VirusDisease, 2021

Aerosol particles can spread respiratory infections, especially those caused by viruses; however,... more Aerosol particles can spread respiratory infections, especially those caused by viruses; however, the perceived threat is small for many technical reasons, as identified in this article. Under controlled conditions, aerosol particles can travel up to a distance of 28 feet (or 8 m); however, such aerosol particles are less likely to have sufficient quantities of viable viruses to spread infection. Additionally, nearly all the experimental models examined the behavior of the aerosols only in confined spaces, not in open areas; these findings, therefore, cannot be considered generally applicable. In the absence of scientific information and education, only misconceptions, unfounded fears, and unsubstantiated myths will prevail. Given that an effective vaccine and drugs are still not available, prevention remains the only option of protection against SARS-CoV-2, the new coronavirus. Wearing a mask is not only necessary but also critical to reduce the probability of viral spread by contact (fomite), not aerosol, transmission. Keywords Virus Á Coronavirus Á SARS-CoV-2 Á COVID-19 Á Aerosol particle Á Facemask VirusDis.

Frontiers in Immunology, 2020

Recent spread of the promoter variant (4-κB) Human immunodeficiency virus-1 clade C (HIV-1C) stra... more Recent spread of the promoter variant (4-κB) Human immunodeficiency virus-1 clade C (HIV-1C) strain is attributed to duplication of the Nuclear Factor Kappa B (NF-κB) binding sites and potential increased heroin consumption in India. To study the underlying biology of 4-κB HIV-1C in rhesus macaques, we engineered a promoter-chimera variant (4NF-κB) Simian Human Immunodeficiency Virus (SHIV) by substituting the HIV-1C Long Terminal Repeat (LTR) region consisting of 4 NF-κB and 3 Sp-1 sites with the corresponding segment in the LTR of SHIV AD8EO. The wild-type (3NF-κB) promoter-chimera SHIV was generated by inactivating the 5 ′ proximal NF-κB binding site in SHIV 4NF-κB. CD8-depleted rhesus macaque PBMCs (RM-PBMCs) were infected with the promoter-chimera and AD8EO SHIVs to determine the effects of opioid-exposure on inflammation, NF-κB activation, neurotoxicity in neuronal cells and viral replication. Morphine-exposure of RM-PBMCs infected with SHIVs 4NF-κB, 3NF-κB, and AD8EO altered cellular transcript levels of monocyte chemoattractant protein 1, interleukin 6, interleukin 1β, and Tumor Necrosis Factor α. Of note, divergent alteration of the cytokine transcript levels was observed with these promoter-chimera wild-type and variant SHIVs. NF-κB activation was observed during infection of all three SHIVs with morphine-exposure. Finally, we observed that SHIV AD8EO infection and exposure to both morphine and naloxone had the greatest impact on the neurotoxicity. The promoter-chimera SHIV 4NF-κB and SHIV 3NF-κB did not have a similar effect on neurotoxicity as compared to SHIV AD8EO. All SHIVs replicated efficiently at comparable levels in RM-PBMCs and morphine-exposure did not alter viral replication kinetics. Future in vivo studies in rhesus macaques will provide greater understanding of 4-κB HIV-1C viral immunopathogenesis and onset of disease in the central nervous system during morphine-exposure.

Pediatric Exercise Science, 2019

Aim: To compare the markers of inflammation and immune activation in virally suppressed HIV-infec... more Aim: To compare the markers of inflammation and immune activation in virally suppressed HIV-infected children on antiretroviral therapy, who practiced regular structured exercise comprising running and yoga to those who did not over a 2-year period. Methods: This retrospective cohort study included 72 children aged 8 to 16 years divided into 2 groups, exercisers (n = 36) and the nonexercisers (n = 36) based on their intentional physical activity. The analyses were carried out at baseline and after 2 years (Y2) for the soluble biomarkers of inflammation and immune activation (tumor necrosis factor alpha, interleukin-6, interleukin-10, interferon gamma, sCD14, and sCD163). In addition, cell-associated biomarker (CD38), lipopolysaccharides, and the gene expression of interleukin-2 and brain-derived neurotrophic factor were also measured at Y2. Results: Reduction in levels of sCD14 (effect size [ES], −0.6; 95% confidence interval [CI], −1.08 to −0.14), tumor necrosis factor alpha (ES, −...

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... Udaykumar Ranga uday@jncasr.ac.in Jawaharlal Nehru Center for Advanced Scientific Research Ja... more ... Udaykumar Ranga uday@jncasr.ac.in Jawaharlal Nehru Center for Advanced Scientific Research Jakkur, Bangalore, India Abstract ... Dk}, the problem is to find the codon sequence, SC = c1c2c3…………cJ, where each ci ∈ C(ai), 1≤ i ≤ J, and the DNA sequence, SD ...

Journal of Medical Virology, 2019

Using cell-associated DNA and cell-free RNA of HIV-1, we investigated the role of drugresistant v... more Using cell-associated DNA and cell-free RNA of HIV-1, we investigated the role of drugresistant viral variants that emerged during early antiretroviral therapy (ART) in determining virological outcome. This case-control study compared virologic non-responder children (two viral loads ≥200 copies/ml within two years of ART) and responder children (two VLs <200 copies/ml after six months of ART) infected with HIV-1 initiated on nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART. The partial reverse transcriptase gene of HIV-1 in cell-associated DNA was genotyped using next-generation

Background: India has the third largest HIV-1 epidemic with 2.4 million infected individuals. Mol... more Background: India has the third largest HIV-1 epidemic with 2.4 million infected individuals. Molecular epidemiological analysis has identified the predominance of HIV-1 subtype C (HIV-1C). However, the previous reports have been limited by sample size, and uneven geographical distribution. The introduction of HIV-1C in India remains uncertain due to this lack of structured studies. To fill the gap, we characterised the distribution pattern of HIV-1 subtypes in India based on data collection from nationwide clinical cohorts between 2007 and 2011. We also reconstructed the time to the most recent common ancestor (tMRCA) of the predominant HIV-1C strains. Methodology/Principal Findings: Blood samples were collected from 168 HIV-1 seropositive subjects from 7 different states. HIV-1 subtypes were determined using two or three genes, gag, pol, and env using several methods. Bayesian

Tat/Rev Induced Limiting Dilution Assay (TILDA) is instrumental in estimating the size of latent ... more Tat/Rev Induced Limiting Dilution Assay (TILDA) is instrumental in estimating the size of latent reservoirs of HIV-1. Here, we report an optimized TILDA containing a broader detection range compared to the reported methods and high sensitivity. Giving priority to sequence conservation, we positioned the two forward primers and the probe in exon-1 of HIV-1. The reverse primers are positioned in highly conserved regions of exon-7. The optimized TILDA detected eight molecular clones belonging to five major genetic subtypes of HIV-1 with a comparable detection sensitivity. Using the optimized assay, we show that only a minor proportion of CD4+ T cells of primary clinical samples can spontaneously generate multiply spliced viral transcripts. A significantly larger proportion of the cells produced viral transcripts following activation. The optimized TILDA is suitable to characterize HIV-1 latent reservoirs and the therapeutic strategies intended to target the reservoir size.

Frontiers in Immunology, 2020

The natural cysteine to serine variation at position 31 of Tat in HIV-1C disrupts the dicysteine ... more The natural cysteine to serine variation at position 31 of Tat in HIV-1C disrupts the dicysteine motif attenuating the chemokine function of Tat. We ask if there exists a trade-off in terms of a gain of function for HIV-1C Tat due to this natural variation. We constructed two Tat-expression vectors encoding Tat proteins discordant for the serine 31 residue (CS-Tat vs. CC-Tat), expressed the proteins in Jurkat cells under doxycycline control, and performed the whole transcriptome analysis to compare the early events of Tat-induced host gene expression. Our analysis delineated a significant enrichment of pathways and gene ontologies associated with the angiogenic signaling events in CS-Tat stable cells. Subsequently, we validated and compared angiogenic signaling events induced by CS- vs. CC-Tat using human umbilical vein endothelial cells (HUVEC) and the human cerebral microvascular endothelial cell line (hCMEC/D3). CS-Tat significantly enhanced the production of CCL2 from HUVEC and ...

In a multicentric, observational, investigator-blinded, and longitudinal clinical study of 764 AR... more In a multicentric, observational, investigator-blinded, and longitudinal clinical study of 764 ART-naïve subjects, we identified nine different promoter-variant strains of HIV-1 subtype C (HIV-1C) emerging in the Indian population, with some of these variants being reported for the first time. Unlike several previous studies, our work here focuses on the evolving viral regulatory elements, not coding sequences. The emerging viral strains contain additional copies of the existing transcription factor binding sites (TFBS), including TCF-1α/LEF-1, RBEIII, AP-1, and NF-κB, created by sequence duplication. The additional TFBS are genetically diverse and may blur the distinction between the modulatory region of the promoter and the viral enhancer. In a follow-up analysis, we found trends, but not significant associations between any specific variant promoter and prognostic markers, probably because the emerging viral strains might not have established mono infections yet. Illumina sequenc...

The magnitude of transcription factor binding site variation emerging in HIV-1C, especially the a... more The magnitude of transcription factor binding site variation emerging in HIV-1C, especially the addition of NF-κB motifs by sequence duplication, makes the examination of transcriptional silence challenging. How can HIV-1 establish and maintain latency despite having a strong LTR? We constructed panels of sub-genomic reporter viral vectors with varying copy numbers of NF-κB motifs (0 to 4 copies) and examined the profile of latency establishment in Jurkat cells. We found surprisingly that the stronger the viral promoter, the faster the latency establishment. Importantly, at the time of commitment to latency and subsequent points, Tat levels in the cell were not limiting. Using highly sensitive strategies, we demonstrate the presence of Tat in the latent cell, recruited to the latent LTR. Our data allude, for the first time, to Tat establishing a negative feedback loop during the late phases of viral infection, leading to the rapid silencing of the viral promoter.ImportanceOver the p...

The Journal of biological chemistry, Jan 17, 2018

HIV-1 subtype C (HIV-1C) may duplicate longer amino acid stretches in the p6 Gag protein, leading... more HIV-1 subtype C (HIV-1C) may duplicate longer amino acid stretches in the p6 Gag protein, leading to the creation of an additional Pro-Thr/Ser-Ala-Pro (PTAP) motif necessary for viral packaging. However, the biological significance of a duplication of the PTAP motif for HIV-1 replication and pathogenesis has not been experimentally validated. In a longitudinal study of two different clinical cohorts of select HIV-1 seropositive, drug-naive individuals from India, we found that 8 of 50 of these individuals harbored a mixed infection of viral strains discordant for the PTAP duplication. Conventional and next-generation sequencing of six primary viral quasispecies at multiple time points disclosed that in a mixed infection, the viral strains containing the PTAP duplication dominated the infection. The dominance of the double-PTAP viral strains over a genetically similar single-PTAP viral clone was confirmed in viral proliferation and pairwise competition assays. Of note, in the proximi...

Retrovirology

Background We observe the emergence of several promoter-variant viral strains in India during rec... more Background We observe the emergence of several promoter-variant viral strains in India during recent years. The variant viral promoters contain additional copies of transcription factor binding sites present in the viral modulatory region or enhancer, including RBEIII, LEF-1, Ap-1 and/or NF-κB. These sites are crucial for governing viral gene expression and latency. Here, we infer that one variant viral promoter R2N3-LTR containing two copies of RBF-2 binding sites (an RBEIII site duplication) and three copies of NF-κB motifs may demonstrate low levels of gene expression noise as compared to the canonical RN3-LTR or a different variant R2N4-LTR (a duplication of an RBEIII site and an NF-κB motif). To demonstrate this, we constructed a panel of sub-genomic viral vectors of promoter-variant LTRs co-expressing two reporter proteins (mScarlet and Gaussia luciferase) under the dual-control of Tat and Rev. We established stable pools of CEM.NKR-CCR5 cells (CEM-CCR5RL reporter cells) and e...

Scientific Reports, 2016

The delivery of plasmid DNA to the skin can target distinct subsets of dermal dendritic cells to ... more The delivery of plasmid DNA to the skin can target distinct subsets of dermal dendritic cells to confer a superior immune response. The needle-free immunization technology offers a reliable, safe and efficient means to administer intradermal (ID) injections. We report here that the ID injection of DNA vectors using an NF device (NF-ID) elicits a superior cell-mediated immune response, at much lesser DNA dosage, comparable in magnitude to the traditional intramuscular immunization. However, the humoral response is significantly impaired, possibly at the stage of B cell isotype switching. We found that the NF-ID administration deposits the DNA primarily on the epidermis resulting in a rapid loss of the DNA as well as the synthesized antigen due to the faster regeneration rate of the skin layers. Therefore, despite the immune-rich nature of the skin, the NF-ID immunization of DNA vectors may be limited by the impaired humoral response. Additional booster injections are required to augment the antibody response. As an alternative and a viable solution, we rescued the IgG response by coadministration of a Toll-like receptor 9 agonist, among other adjuvants examined. Our work has important implication for the optimization of the emerging needle-free technology for ID immunization.

BMC infectious diseases, Jan 24, 2017

HIV-1 subtype C demonstrates several biological properties distinct from other viral subtypes. On... more HIV-1 subtype C demonstrates several biological properties distinct from other viral subtypes. One such variation is the duplication of PTAP motif in p6 Gag. PTAP motif is a key player in viral budding. Here, we studied the prevalence of PTAP motif duplication in subtype C viral strains in a longitudinal study. In a prospective follow-up study, 65 HIV-1 seropositive drug-naive subjects were monitored in two different clinical cohorts of India for 2 years with repeated sampling at 6-month intervals. The viral RNA was extracted from plasma, the gag segment was amplified and sequenced. From a subset of viral isolates the sequences of pol, env and LTR were sequenced. Using HIV-1 gag amino acid sequences available from public databases and additional sequences derived from the Indian and South-African cohorts, we examined the nature of PTAP motif duplication in subtype C. In 16% (8 of 50) of the primary viral strains of India, we identified a sequence duplication of the PTAP motif in Gag...