Mitochondrial quality control: Epigenetic signatures and therapeutic strategies.

Mitochondria are semi-autonomous organelle staging a crucial role in cellular stress response, energy metabolism and cell survival. Maintaining mitochondrial quality control is very important for its homeostasis. Pathological conditions such as oxidative stress and neurodegeneration, disrupt this quality control, and involvement of genetic and epigenetic materials in this disruption have been reported. These regulatory factors trigger mitochondrial imbalance, as seen in many neurodegenerative diseases like Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, and Huntington's disease. The dynamic regulatory pathways i.e. mitophagy, biogenesis, permeability pore transitioning, fusion-fission are affected as a consequence and have been reviewed in this article. Moreover, several epigenetic mechanisms such as DNA methylation and histone modulation participating in such neurological disorders have also been discussed. Apart from it, therapeutic approaches targeting mitochondrial quality control have been tremendously explored showing ameliorative effects for these diseases, and have been discussed here with a novel perspective.

Effect of baseline micronutrient and inflammation status on CD4 recovery post-cART initiation in the multinational PEARLS trial.

BACKGROUND & AIMS: Nutritional deficiency and inflammation may impact CD4+ T cell recovery during combination antiretroviral therapy (cART), particularly in resource-limited settings where malnutrition is prevalent. The aim of this study was to investigate the relationship of micronutrient and inflammation biomarkers to CD4 recovery after cART initiation. METHODS: We conducted a secondary analysis of a random sub-cohort sample (n = 270) from a multinational randomized trial of cART regimen efficacy among 1571 cART-naïve adults. We measured pre-cART serum levels of micronutrients (Vitamin A, B6, B12, D, total carotenoids, selenium, and iron) and inflammation (C-reactive protein, soluble CD14 (sCD14), IFNγ, TNFα, Interleukin-6, and C-X-C motif chemokine 10 (CXCL10/IP10), EndoCab (IgM)) biomarkers. Biomarker status (i.e. micronutrient deficiency vs. sufficiency and elevated vs. low inflammation) was defined using established cutoffs or quartiles. Mixed-effects linear regression models were used to determine the association of baseline (pre-cART) concentrations of individual biomarkers with CD4 recovery through 96 weeks post-cART initiation. RESULTS: In models adjusting for time-dependent viral load and baseline CD4 count, age, sex, body mass index, country, treatment regimen, anemia and hypoalbuminemia status, pre-cART vitamin D deficiency was associated with lower CD4 recovery (-14.9 cells/mm3, 95% CI: -27.9, -1.8) compared to sufficiency. In contrast, baseline selenium deficiency (20.8 cells/mm3, 95% CI: 3.3, 38.3), vitamin A deficiency (35.9 cells/mm3, 95% CI: 17.6, 54.3) and high sCD14 (23.4 cells/mm3, 95% CI: 8.9, 37.8) were associated with higher CD4 recovery compared to sufficient/low inflammation status. CONCLUSIONS: In summary, baseline vitamin D deficiency was associated with diminished CD4 recovery after cART initiation; impaired CD4 recovery may contribute to the poor clinical outcomes recently observed in individuals with vitamin D deficiency. Vitamin A, selenium and sCD14 were associated with CD4 recovery but future studies are needed to further explore these relationships.

Higher expression of human telomerase reverse transcriptase in productively-infected CD4 cells possibly indicates a mechanism for persistence of the virus in HIV infection.

Mechanisms involved in survival of productively-infected memory CD4+cells after initial antigenic stimulation and their subsequent reversion to the resting state are critical for the development of a predominant replication-competent HIV reservoir. These mechanisms may also counter their elimination after HIV reactivation through latency-reversing agents (LRA). Thus, their evaluation is critical when using an appropriate HIV latency model that recapitulates the predominant replication-competent HIV reservoir to develop strategies for HIV eradication. The model for evaluating the possible survival mechanisms after T cell receptor (TCR) stimulation was developed by infecting memory CD4+cells with an HIV-1C primary isolate and cytokine secretion and gene expression patterns determined. Infected cells showed compromised functionality as evident from 6.8-fold lower secretion of IL-2 than from uninfected control cells. After TCR stimulation, the infected cells showed significantly higher fold increases in CD27 and CCR5 and smaller increases in CD5 mRNA over baseline values. Because CD27 expression may influence telomerase activity through AKT phosphorylation, CD27, human telomerase reverse transcriptase (hTERT) and pAKT expression in productively-infected cells from HIV-infected patients was evaluated by flow cytometry. HIV harbored in memory CD4+ cells was reactivated by HIV-1 envelope peptides, which have been shown to act as effective LRA. P24+CD4+cell showed significantly higher expression of CD27, hTERT and pAKT than P24-CD4+cells. These findings indicate compromised functionality of HIV-infected cells after TCR stimulation, which may interfere with their elimination by the immune system. They also indicate that pAKT and hTERT induction are possible survival mechanisms of productively-infected CD4+cells.

Sex-Related Differences in Inflammatory and Immune Activation Markers Before and After Combined Antiretroviral Therapy Initiation.

BACKGROUND: Women progress to death at the same rate as men despite lower plasma HIV RNA (viral load). We investigated sex-specific differences in immune activation and inflammation as a potential explanation. METHODS: Inflammatory and immune activation markers [interferon γ, tumor necrosis factor (TNF) α, IL-6, IL-18, IFN-γ-induced protein 10, C-reactive protein (CRP), lipopolysaccharide, and sCD14] were measured at weeks 0, 24, and 48 after combination antiretroviral therapy (cART) in a random subcohort (n = 215) who achieved virologic suppression in ACTG A5175 (Prospective Evaluation of Antiretrovirals in Resource-Limited Settings). Association between sex and changes in markers post-cART was examined using random effects models. Average marker differences and 95% confidence intervals were estimated using multivariable models. RESULTS: At baseline, women had lower median log10 viral load (4.93 vs 5.18 copies per milliliter, P = 0.01), CRP (2.32 vs 4.62 mg/L, P = 0.01), detectable lipopolysaccharide (39% vs 55%, P = 0.04), and sCD14 (1.9 vs 2.3 µg/mL, P = 0.06) vs men. By week 48, women had higher interferon γ (22.4 vs 14.9 pg/mL, P = 0.05), TNF-α (11.5 vs 9.5 pg/mL, P = 0.02), and CD4 (373 vs 323 cells per cubic millimeter, P = 0.02). In multivariate analysis, women had greater increases in CD4 and TNF-α but less of a decrease in CRP and sCD14 compared with men. CONCLUSIONS: With cART-induced viral suppression, women have less reduction in key markers of inflammation and immune activation compared with men. Future studies should investigate the impact of these sex-specific differences on morbidity and mortality.

Coding region variant 186H/R in Exon 4 of APOBEC3G among individuals of Western India.

The allelic variations in the AIDS restriction genes have been associated with the acquisition of HIV-1 and its progression. The distribution of antiviral gene variants significantly differs between populations. Therefore, we aimed to evaluate the distribution of variant allele of 186H/R in exon4 of APOBEC3G between HIV infected individuals and healthy controls among western Indian.In the present cross-sectional study, we enrolled a total of 153 HIV-infected patients confirmed and 156 unrelated healthy individuals. Polymorphism for 186H/R in exon4 of APOBEC3G gene was genotyped by PCR-RFLP. With the frequency of 186HR heterozygous genotype of APOBEC3G was found to be 13% in healthy controls and none in HIV infected cases. The frequency of 186HH common genotype of APOBEC3G was observed higher in HIV infected individuals compared with healthy controls (100% vs 91.7%). The variant genotype 186RR in APOBEC3G was not found in both the groups. The frequency of 186R allele of APOBEC3G was found 4.16% in healthy controls and nil in HIV-infected cases. The frequency of 186H allele of APOBEC3G was found to be higher in HIV-infected cases compared with healthy controls (100% vs 95.83%). The frequency of 186R allele in exon4 of APOBEC3G was found to be 4.16% in healthy controls. This observation differs from the previous report published from North India stating the absence of 186R allele of APOBEC3G in the North Indian individuals. The variant 186H/R in exon4 of APOBEC3G was neither associated with risk of acquisition of HIV-1 nor its progression.

Pre-cART Elevation of CRP and CD4+ T-Cell Immune Activation Associated With HIV Clinical Progression in a Multinational Case-Cohort Study.

BACKGROUND: Despite the success of combination antiretroviral therapy (cART), a subset of HIV-infected patients who initiate cART develop early clinical progression to AIDS; therefore, some cART initiators are not fully benefitted by cART. Immune activation pre-cART may predict clinical progression in cART initiators. METHODS: A case-cohort study (n = 470) within the multinational Prospective Evaluation of Antiretrovirals in Resource-Limited Settings clinical trial (1571 HIV treatment-naive adults who initiated cART; CD4 T-cell count <300 cells/mm; 9 countries) was conducted. A subcohort of 30 participants per country was randomly selected; additional cases were added from the main cohort. Cases [n = 236 (random subcohort 36; main cohort 200)] had clinical progression (incident WHO stage 3/4 event or death) within 96 weeks after cART initiation. Immune activation biomarkers were quantified pre-cART. Associations between biomarkers and clinical progression were examined using weighted multivariable Cox-proportional hazards models. RESULTS: Median age was 35 years, 45% were women, 49% black, 31% Asian, and 9% white. Median CD4 T-cell count was 167 cells per cubic millimeter. In multivariate analysis, highest quartile C-reactive protein concentration [adjusted hazard ratio (aHR), 2.53; 95% confidence interval (CI): 1.02 to 6.28] and CD4 T-cell activation (aHR, 5.18; 95% CI: 1.09 to 24.47) were associated with primary outcomes, compared with lowest quartiles. sCD14 had a trend toward association with clinical failure (aHR, 2.24; 95% CI: 0.96 to 5.21). CONCLUSIONS: Measuring C-reactive protein and CD4 T-cell activation may identify patients with CD4 T-cell counts <300 cells per cubic millimeter at risk for early clinical progression when initiating cART. Additional vigilance and symptom-based screening may be required in this subset of patients even after beginning cART.

C-reactive protein (CRP), interferon gamma-inducible protein 10 (IP-10), and lipopolysaccharide (LPS) are associated with risk of tuberculosis after initiation of antiretroviral therapy in resource-limited settings.

OBJECTIVE: The association between pre-antiretroviral (ART) inflammation and immune activation and risk for incident tuberculosis (TB) after ART initiation among adults is uncertain. DESIGN: Nested case-control study (n = 332) within ACTG PEARLS trial of three ART regimens among 1571 HIV-infected, treatment-naïve adults in 9 countries. We compared cases (participants with incident TB diagnosed by 96 weeks) to a random sample of controls (participants who did not develop TB, stratified by country and treatment arm). METHODS: We measured pre-ART C-reactive protein (CRP), EndoCab IgM, ferritin, interferon gamma (IFN-γ), interleukin 6 (IL-6), interferon gamma-inducible protein 10 (IP-10), lipopolysaccharide (LPS), soluble CD14 (sCD14), tumor necrosis factor alpha (TNF-α), and CD4/DR+/38+ and CD8/DR+/38+ T cells. Markers were defined according to established cutoff definitions when available, 75th percentile of measured values when not, and detectable versus undetectable for LPS. Using logistic regression, we measured associations between biomarkers and incident TB, adjusting for age, sex, study site, treatment arm, baseline CD4 and log10 viral load. We assessed the discriminatory value of biomarkers using receiver operating characteristic (ROC) analysis. RESULTS: Seventy-seven persons (4.9%) developed incident TB during follow-up. Elevated baseline CRP (aOR 3.25, 95% CI: 1.55-6.81) and IP-10 (aOR 1.89, 95% CI: 1.05-3.39), detectable plasma LPS (aOR 2.39, 95% CI: 1.13-5.06), and the established TB risk factors anemia and hypoalbuminemia were independently associated with incident TB. In ROC analysis, CRP, albumin, and LPS improved discrimination only modestly for TB risk when added to baseline routine patient characteristics including CD4 count, body mass index, and prior TB. CONCLUSION: Incident TB occurs commonly after ART initiation. Although associated with higher post-ART TB risk, baseline CRP, IP-10, and LPS add limited value to routine patient characteristics in discriminating who develops active TB. Besides determining ideal cutoffs for these biomarkers, additional biomarkers should be sought that predict TB disease in ART initiators.

Cardiac morbidity in an HIV-1 lipodystrophy patient cohort expressing the TNF-α-238 G/A single nucleotide gene polymorphism.

In the current study we investigated the prevalence of the TNF-α 238G/A single nucleotide polymorphism (SNP) of the TNF-α gene in the development of lipodystrophy among HIV-1 infected individuals who had been receiving antiretroviral therapy (ART) in the immunodeficiency clinics of the National AIDS Research Institute (NARI) at Pune, India. We assessed the association of this SNP with the development of lipoatrophy/dyslipidemia and insulin resistance in these patients and measured carotid intima thickening which is a surrogate marker for chronic cardiac morbidity. Our results show that the incidence of the TNF-α 238G/A SNP is ~ two fold higher in patients with lipodystrophy as compared to those without lipodystrophy. Patients with lipodystrophy demonstrated a higher likelihood of the development of metabolic syndrome as evident by increased insulin sensitivity and increased percentage (%) ß cell function. Further, a significant increase in left carotid intima thickness was observed in patients with lipodystrophy. Our study validates the association of the TNF-α 238G/A SNP allelic variant with the development of HIV- lipodystrophy via the modulation of TNF-α production, which contributes to dyslipidemia, increased lipolysis, increased insulin resistance, altered differentiation of adipocytes and increased carotid intima thickness. The contribution of genetic determinants such as the TNF-α 238G/A SNP to lipodystrophy, may provide insight into the mechanisms that underlie this disease condition and may be useful in the future for personalized therapy. Additionally, these findings will be useful in monitoring chronic cardiac morbidities among HIV infected individuals who express this SNP.

Clinical profile of HIV infected patients attending a HIV referral clinic in Pune, India.

BACKGROUND & OBJECTIVES: Human immunodeficiency virus (HIV) has infected several million individuals in India. Various interventions have been implemented for early detection and prevention of transmission of HIV infection. This has progressively changed the clinical profile of HIV infected individuals and this study documents the clinical presentation of individuals positive for HIV in 2010, in Pune, Maharashtra, India. METHODS: This cross-sectional study included subjects who had come to the HIV referral clinic for HIV testing from January to December 2010. Children as well as individuals with indeterminate HIV result were excluded from the study, and data for 1546 subjects were finally analysed. RESULTS: The HIV positivity rate among all referred cases for the year 2010 was 35 per cent (male 55% and females 45%). The median age (Q1, Q3) was 31 (25.75, 39) yr. The median CD4 cell count for all HIV infected individuals (whose CD4 count was available n=345) was 241 cells/µl and for asymptomatic HIV infected individuals was 319 cells/µl. There were 673 (43.5%) symptomatic and 873 (56.5%) asymptomatic participants. Fever, breathlessness, cough with expectoration, weight loss, loss of appetite, generalized weakness, pallor and lymphadenopathy (axillary and cervical) were found to be associated (P<0.001) with HIV positivity. On multivariate analysis, history of Herpes zoster [AOR 11.314 (6.111-20.949)] and TB [AOR 11.214 (6.111-20.949)] was associated with HIV positivity. INTERPRETATION & CONCLUSIONS: Signs and symptoms associated with HIV positivity observed in this study can be used by health care providers to detect HIV infection early. Moreover, similar to HIV testing in patients with tuberculosis, strategies can be developed for considering Herpes zoster as a predictor of HIV infection.

Short communication: HIV antigen-specific reactivation of HIV infection from cellular reservoirs: implications in the settings of therapeutic vaccinations.

Therapeutic vaccinations using human immunodeficiency virus (HIV) antigens in HIV-infected patients on antiretroviral therapy (ART) have so far been attempted with the purpose of inducing CTL response. However, they can also be useful as a strategy for activation of latent HIV reservoir, which is thought to be mainly comprised of latently infected HIV-specific memory CD4 cells, eventually leading to elimination of the virus. The present study was carried out to explore the ability of different HIV antigens to activate HIV replication as assessed by intracellular P24 detection as well as to induce T cell responses in terms of cytokine expression by flow cytometry after stimulation of PBMCs from HIV-infected patients. HIV antigens were found to be able to activate most of the CD4 T cells harboring proviral DNA. HIV-1 Pol and Env were responsible for induction of higher HIV replication in terms of both magnitude and frequency followed by Gag and Nef. As opposed to this, Pol and Env contributed to fewer numbers of polyfunctional CD8 cells desirable for elimination of HIV-infected cells in comparison to Gag and Nef. Thus, HIV antigens may provide a strategy for the activation of a latent reservoir. It was observed that HIV replication started as early as half an hour after in vitro activation indicating a stringent need for maintaining effective concentrations of antiretroviral drugs to prevent further spread of HIV during this process. HIV-infected cells were found to be responsible for higher IL-10 secretion after activation, which could also serve as one of the reasons for suppressed CD8 responses to Pol and Env as more HIV-infected CD4 cells would be secreting IL-10 in response to these antigens. Since IL-10 blockade helped to improve immune responses in terms of cytokine secretion, it should be considered in settings of therapeutic vaccination to improve CTL responses, which will ultimately limit the persistence of the viral reservoir.