Modulation of the Circadian Rhythm and Oxidative Stress as Molecular Targets to Improve Vascular Dementia: A Pharmacological Perspective.

The circadian rhythms generated by the master biological clock located in the brain's hypothalamus influence central physiological processes. At the molecular level, a core set of clock genes interact to form transcription-translation feedback loops that provide the molecular basis of the circadian rhythm. In animal models of disease, a desynchronization of clock genes in peripheral tissues with the central master clock has been detected. Interestingly, patients with vascular dementia have sleep disorders and irregular sleep patterns. These alterations in circadian rhythms impact hormonal levels, cardiovascular health (including blood pressure regulation and blood vessel function), and the pattern of expression and activity of antioxidant enzymes. Additionally, oxidative stress in vascular dementia can arise from ischemia-reperfusion injury, amyloid-beta production, the abnormal phosphorylation of tau protein, and alterations in neurotransmitters, among others. Several signaling pathways are involved in the pathogenesis of vascular dementia. While the precise mechanisms linking circadian rhythms and vascular dementia are still being studied, there is evidence to suggest that maintaining healthy sleep patterns and supporting proper circadian rhythm function may be important for reducing the risk of vascular dementia. Here, we reviewed the main mechanisms of action of molecular targets related to the circadian cycle and oxidative stress in vascular dementia.

HIV-1 Tat Induces Dysregulation of PGC1-Alpha and Sirtuin 3 Expression in Neurons: The Role of Mitochondrial Biogenesis in HIV-Associated Neurocognitive Disorder (HAND).

During the antiretroviral era, individuals living with HIV continue to experience milder forms of HIV-associated neurocognitive disorder (HAND). Viral proteins, including Tat, play a pivotal role in the observed alterations within the central nervous system (CNS), with mitochondrial dysfunction emerging as a prominent hallmark. As a result, our objective was to examine the expression of genes associated with mitophagy and mitochondrial biogenesis in the brain exposed to the HIV-1 Tat protein. We achieved this by performing bilateral stereotaxic injections of 100 ng of HIV-1 Tat into the hippocampus of Sprague-Dawley rats, followed by immunoneuromagnetic cell isolation. Subsequently, we assessed the gene expression of Ppargc1a, Pink1, and Sirt1-3 in neurons using RT-qPCR. Additionally, to understand the role of Tert in telomeric dysfunction, we quantified the activity and expression of Tert. Our results revealed that only Ppargc1a, Pink1, and mitochondrial Sirt3 were downregulated in response to the presence of HIV-1 Tat in hippocampal neurons. Interestingly, we observed a reduction in the activity of Tert in the experimental group, while mRNA levels remained relatively stable. These findings support the compelling evidence of dysregulation in both mitophagy and mitochondrial biogenesis in neurons exposed to HIV-1 Tat, which in turn induces telomeric dysfunction.

Sirtuins Modulation: A Promising Strategy for HIV-Associated Neurocognitive Impairments.

HIV-Associated neurocognitive disorder (HAND) is one of the major concerns since it persists in 40% of this population. Nowadays, HAND neuropathogenesis is considered to be caused by the infected cells that cross the brain-blood barrier and produce viral proteins that can be secreted and internalized into neurons leading to disruption of cellular processes. The evidence points to viral proteins such as Tat as the causal agent for neuronal alteration and thus HAND. The hallmarks in Tat-induced neurodegeneration are endoplasmic reticulum stress and mitochondrial dysfunction. Sirtuins (SIRTs) are NAD+-dependent deacetylases involved in mitochondria biogenesis, unfolded protein response, and intrinsic apoptosis pathway. Tat interaction with these deacetylases causes inhibition of SIRT1 and SIRT3. Studies revealed that SIRTs activation promotes neuroprotection in neurodegenerative diseases such Alzheimer's and Parkinson's disease. Therefore, this review focuses on Tat-induced neurotoxicity mechanisms that involve SIRTs as key regulators and their modulation as a therapeutic strategy for tackling HAND and thereby improving the quality of life of people living with HIV.

Downregulation of SERINC5 expression in buffy coats of HIV-1-infected patients with detectable or undetectable viral load.

Among the host restriction factors against HIV, SERINC5 has been described in vitro, but the mRNA level of SERINC5 in vivo has been little studied. We compare SERINC5 expression in subjects with HIV-1 (highly active antiretroviral treatment (HAART) and HAART-naïve) with and without suppression of viral load. A cross-sectional study was performed with 107 individuals distributed as follows: 24 with HAART-naïve and detectable viral load (> 50 copies/mL), 13 with HAART and detectable viral load (> 50 copies/mL), 50 with HAART and undetectable viral load (≤ 50 copies/mL), and 20 without HIV-1. SERINC5 expression in buffy coats was determined using RT-qPCR. The viral load was determined using real-time PCR and the amount of CD4 + and CD8 + T-lymphocytes was measured using flow cytometry. The data were normalized with the Shapiro-Wilk test and the Kruskal-Wallis test was subsequently performed. The relative expression was compared with a T-test and the remaining data with the Mann-Whitney U-test. ANCOVA multiple linear regression analysis was performed between characteristics of patients with SERINC5 expression. The mean and SD of the SERINC5 expression in the three groups with HIV-1 was 0.9 ± 0.2 and without HIV-1 was 1.7 ± 0.14 (P < 0.001). Multiple linear regression did not show the participation of CD4 +, CD8 + , viral load, infection time, or treatment time. No differences in the SERINC5 expression were found among the studied groups of patients with HIV-1. When comparing the groups with and without HIV-1 infection, SERINC5 was downregulation in the HIV-1 groups.

Genomic instability in people living with HIV.

The increased life expectancy of people living with HIV (PLWH) receiving antiretroviral treatment (ART) has transformed HIV infection into a chronic disease. However, patients may be at risk of accelerated aging and the accumulation of cellular damage, which may trigger the development of cancer. We evaluated genomic instability in HIV-positive individuals with different viral loads receiving antiretroviral treatment (ART) and in HIV ART-naïve individuals. We included 67 participants divided into four groups: group 1 (n = 24) HIV patients receiving reverse-transcriptase inhibitors (tenofovir/ emtricitabine/ efavirenz and abacavir/ lamivudine/ efavirenz), group 2 (n = 22) HIV patients receiving protease inhibitors combined with other antiretroviral drugs (tenofovir/ emtricitabine with ritonavir/ atazanavir or lopinavir/ ritonavir, and darunavir/ ritonavir/ raltegravir), group 3 (n = 13) HIV ART-naïve patients, and group 4 (n = 8) healthy individuals (controls). Nuclear abnormalities in buccal mucosal samples (micronuclei, binucleated cells, nuclear buds, karyorrhexis, karyolysis, and pyknosis) were quantified. Simultaneously, blood samples were taken to quantify CD4+, CD8+, and HIV viral load. There was a significant age difference between HIV ART-naïve patients and receiving ART groups. Infection time was longer in HIV patients with ART than in ART-naïve patients. There were no differences in sex, smoking, alcohol consumption, or number of micronucleated cells between the study groups. We found higher frequencies of binucleated cells and nuclear buds in HIV patients, HIV ART-naïve, and HIV ART patients compared to the control group. We found a positive correlation between nuclear buds and CD4/CD8 ratio in the HIV ART-naïve group. In conclusion, PLWH showed increased genomic instability. The CD4/CD8 ratio affects the numbers of nuclear buds and binucleated cells. These findings are pertinent to mechanisms of damage and possible strategies to mitigate carcinogenesis in PLWH.

MicroRNA-296-5p is differentially expressed in individuals with and without HIV-1 infection.

MicroRNAs are considered as potential biomarkers, agents, or therapeutic targets; few studies have addressed the expression of miRNAs in treatment-naïve patients infected with HIV-1. The aim of this study was to assess plasma relative circulating miRNA expression profiles in treatment-naïve Mexican patients with HIV/AIDS and healthy individuals using a commercial array. A low CD4+ T cell count and high viral load were found in all patients. Decreased relative miRNA-296-5p expression was observed in patients; moreover, this was the only miRNA that showed differences between the two groups. Thus, we measured the absolute expression of miR-296-5p by qPCR, confirming the result with statistically significant differences (P < 0.05). There is evidence that miR-296-5p regulates the expression of the PIN1 gene, which encodes the peptidylprolyl Cis/Trans isomerase NIMA-Interacting-1, that is involved in different stages of the biological cycle of HIV-1, this relationship is corroborated by bioinformatics analysis and ELISA assay was used to measure plasma levels of PIN1. The decreased expression of miR-296-5p found in naïve patients with HIV infection suggests a regulatory activity of this miRNA on virus replication, making it a potential therapeutic agent against HIV. Finally, miR-296-5p could be inhibiting the virus transcription by regulating genes different than PIN1.

Plasma microRNA expression levels in HIV-1-positive patients receiving antiretroviral therapy.

MicroRNAs (miRNAs/miRs) may serve as therapeutic agents or targets in diseases in which the expression of proteins plays an important role. The aim of the present study was to compare the expression levels of specific miRNAs, as well as their correlation with markers of response to antiretroviral (ARV) therapy, in patients with human immunodeficiency virus type 1 (HIV-1) infection with and without resistance to highly active antiretroviral therapy (HAART). METHODS: miRNA assays were performed on plasma samples obtained from 20 HIV-1-positive patients. A total of ten patients were divided into two groups: HAART-responsive and HAART-resistant (n=5 per group). Commercial arrays were subsequently used to identify 84 miRNAs. A total of three differentially expressed miRNAs were selected and analyzed by quantitative PCR (qPCR). Five other patients were subsequently added to each group for a new relative expression analysis. The absolute expression level of the two miRNAs was obtained and compared using the Student's t test. Receiver operating characteristic (ROC) curves were used to identify patients with antiretroviral therapy (ART) resistance. RESULTS: The array analysis revealed that miR-15b-5p, miR-16-5p, miR-20a-5p, miR-26a-5p, miR-126-3p and miR-150-5p were down-regulated in patients with HAART-resistance comparing with HAART-responsive. The expression levels of miR-16-5p, miR-26a-5p and miR-150-5p were confirmed using qPCR. The area under the ROC curve was 1.0 for the three miRNAs. CONCLUSIONS: The lower expression levels of miR-16-5p and miR-26a-5p in patients with HAART-resistance suggested that these may serve as potential biomarkers for the identification of HAART-responsive patients.

SERINC as a Restriction Factor to Inhibit Viral Infectivity and the Interaction with HIV.

The serine incorporator 5 (SERINC5) is a recently discovered restriction factor that inhibits viral infectivity by preventing fusion. Retroviruses have developed strategies to counteract the action of SERINC5, such as the expression of proteins like negative regulatory factor (Nef), S2, and glycosylated Gag (glycoGag). These accessory proteins downregulate SERINC5 from the plasma membrane for subsequent degradation in the lysosomes. The observed variability in the action of SERINC5 suggests the participation of other elements like the envelope glycoprotein (Env) that modulates susceptibility of the virus towards SERINC5. The exact mechanism by which SERINC5 inhibits viral fusion has not yet been determined, although it has been proposed that it increases the sensitivity of the Env by exposing regions which are recognized by neutralizing antibodies. More studies are needed to understand the role of SERINC5 and to assess its utility as a therapeutic strategy.

HIV Drug Resistance in Antiretroviral-Naive Patients in Mexico After 10 Years: Is There a Difference?

The aim of this study was to compare the extent of resistance to antiretroviral (ARV) drugs among the population in Mexico before and after 2005. The mutations and drug resistance database of Stanford University were used for analyzing drug resistance tests that had been performed on HIV treatment-naive patients. The sequences obtained were divided into group 1 (isolated in 2002-2003) and group 2 (isolated in 2010-2014). Both groups showed 14% similarity in resistance mutations. In both groups, mutations in N88D protease inhibitor were identified, D67N and T69D were found for nucleoside reverse transcriptase inhibitors (NRTIs), and K103N was found for non-nucleoside reverse transcriptase inhibitors. In both groups, the resistance to ARV drugs was 7.4%. Both groups showed resistance to nelfinavir, efavirenz, and nevirapine. The prevalence of resistance to ARV therapy remained stable from 2002 to 2014. However, a marked reduction in resistance to NRTIs was observed for the same period.

Riesgo de trastornos alimentarios y perfil antropométricos en modelos profesionales de México / Risk of eating attitudes and anthropometric profile among professional fashion models of Mexico

Objective: The aim of this study was to compare the risk of Eating Disorders Behaviour (EDB), and its anthropometric profile, physical activity and alimentary intake between Mexican fashion models (FM) and control women Methods: We included 50 FM and 50 control women, of the same social group, all over 18 years old, from Guadalajara, Mexico, matched by age. We evaluated the risk of EDB with the Eating Attitudes Test (EAT-26); the anthropometric measures were taken according to the criteria of the International Society for the Advancement of Kinanthropometry (ISAK), 24-hour recall to estimate energy intake and physical activities. Results: The risk prevalence of EDB was 10% for both groups. The mean and standard deviation of the percentage of body fat in FM was 22,4±2, lower than in the controls (27,8±4, p<0.001). There were no differences in anthropometric measurements in women with and without risk of EDB, except in the weight (FM without risk of EDB 56,3±3 kg and 59,9±3 kg with risk of EDB (p<0.02). Caloric intake in women with risk of EDB reduced was 1094±208 kcal in FM versus 1269±435 kcal in control woman. Conclusion: The anthropometric measurements, alimentary intake and previous history of eating disorders, suggests that FM of Mexico are a vulnerable population for eating disorder.

Objetivo: Comparar el riesgo de trastornos de la conducta alimentaria (TCA), perfil antropométrico, actividad física e ingesta alimentaria entre las mujeres mexicanas dedicadas al modelaje profesional (MP) con mujeres control. Métodos: Se incluyeron 50 MP y 50 mujeres controles, del mismo grupo social, mayores de 18 años, de Guadalajara, México, pareadas por edad. Se evaluó el riesgo de TCA con el test de Trastornos de Actitudes Alimentarias (EAT-26), se tomaron las medidas antropométricas de acuerdo a los criterios de la International Society for the Advancement of Kinanthropometry (ISAK). Se estimó el consumo de energía utilizando el recordatorio de 24 horas y se registró la práctica de actividades físicas. Resultados: La prevalencia de riesgo de TCA fue 10% para ambos grupos. La media y desviación estándar del porcentaje de grasa corporal en las MP fue 22,4±2,5 menor al de las controles (27,8±4,9) (p<0.001). No hubo diferencias en la medidas antropométricas en las mujeres con y sin riesgo de TCA, excepto en el peso de las MP de 56,3±3,1 kg sin riesgo de TCA y 59,9±3,6 en las con riesgo de TCA (p<0.02). La ingesta alimentaria se encontró reducida en las mujeres con riesgo de TCA con respecto a las sin riesgo, con 1094,2±208,3 kcal versus 1269,8±435,0 kcal en las MP y controles respectivamente. Conclusión: Las medidas antropométricas, la ingesta alimentaria y la historia previa de trastornos de la alimentación, sugiere que la MP de México es una población vulnerable para trastornos de la alimentación.

Virus-like particles from Escherichia Coli-derived untagged papaya ringspot virus capsid protein purified by immobilized metal affinity chromatography enhance the antibody response against a soluble antigen.

There is a growing interest in using virus-like particles (VLPs) as scaffolds for the presentation of antigens of choice to the immune system. In this work, VLPs from papaya ringspot virus capsid protein expressed in Escherichia coli were evaluated as enhancers of antibody response against a soluble antigen. Interestingly, although the capsid protein lacks a histidine tag, its purification by immobilized metal affinity chromatography was achieved. The formation of VLPs was demonstrated by electron microscopy for the first time for this capsid protein. VLPs were enriched by polyethylene glycol precipitation. Additionally, these VLPs were chemically coupled to green fluorescent protein in order to evaluate them as antigen carriers; however, bioconjugate instability was observed. Nonetheless, the adjuvant effect of these VLPs on BALB/c mice was evaluated, using GFP as antigen, resulting in a significant increase in anti-GFP IgG response, particularly, IgG1 class, demonstrating that the VLPs enhance the immune response against the antigen chosen in this study.

Natural polymorphisms and unusual mutations in HIV-1 protease with potential antiretroviral resistance: a bioinformatic analysis.

BACKGROUND: The correlations of genotypic and phenotypic tests with treatment, clinical history and the significance of mutations in viruses of HIV-infected patients are used to establish resistance mutations to protease inhibitors (PIs). Emerging mutations in human immunodeficiency virus type 1 (HIV-1) protease confer resistance to PIs by inducing structural changes at the ligand interaction site. The aim of this study was to establish an in silico structural relationship between natural HIV-1 polymorphisms and unusual HIV-1 mutations that confer resistance to PIs. RESULTS: Protease sequences isolated from 151 Mexican HIV-1 patients that were naïve to, or subjected to antiretroviral therapy, were examined. We identified 41 unrelated resistance mutations with a prevalence greater than 1%. Among these mutations, nine exhibited positive selection, three were natural polymorphisms (L63S/V/H) in a codon associated with drug resistance, and six were unusual mutations (L5F, D29V, L63R/G, P79L and T91V). The D29V mutation, with a prevalence of 1.32% in the studied population, was only found in patients treated with antiretroviral drugs. Using in silico modelling, we observed that D29V formed unstable protease complexes when were docked with lopinavir, saquinavir, darunavir, tipranavir, indinavir and atazanavir. CONCLUSIONS: The structural correlation of natural polymorphisms and unusual mutations with drug resistance is useful for the identification of HIV-1 variants with potential resistance to PIs. The D29V mutation likely confers a selection advantage in viruses; however, in silico, presence of this mutation results in unstable enzyme/PI complexes, that possibly induce resistance to PIs.

Receptor to glutamate NMDA-type: the functional diversity of the nr1 isoforms and pharmacological properties.

Glutamic acid (Glu) is the major excitatory neurotransmitter in the central nervous system, and interacts with two classes of receptor: metabotropic and ionotropic receptors. Ionotropic receptors are divided according to the affinity of their specific agonists: Nmethyl- D-aspartate (NMDA), amino acid-3-hydroxy-5-methyl-4-isoxazole acid (AMPA) and kainic acid (KA). NMDA receptors (NMDA-R) are macromolecular structures that are formed by different combinations of subunits: NMDAR1 (NR1), NMDAR2 (NR2) and NMDAR3 (NR3). The study of this receptor has aroused great interest, partly due to its role in synaptic plasticity but mainly because of its permeability to the Ca(2+) ion. This review examines the molecular composition of NMDA-R and the variants of NR1 subunit editing in association with NR2 subunit dimers, which form the main components of this receptor. Their composition, structure, function and distinct temporal and spatial expression patterns demonstrate the versatility and diversity of functionally different isoforms of NR1 subunits and the various pharmacological properties of the NR2 subunit. Finally, the involvement of NMDA-R in the excitotoxicity phenomenon, as well as, its expression changes under these conditions as neuronal response are also discussed.

Molecular epidemiology of HIV type 1 in Mexico: emergence of BG and BF intersubtype recombinants.

The molecular epidemiology of subtypes and intersubtype recombinants (IRs) of human immunodeficiency virus type 1 (HIV-1) in Mexico has not been characterized fully. Understanding its regional distribution, prevalence, adaptability, viral fitness, pathogenicity, and immunogenicity is decisive for any design of an effective HIV vaccine. The aim of this study was to describe the presence of IRs types BG and BF in a Mexican population. Protease and reverse transcriptase regions of the pol gene were sequenced using an automated sequencing system. A phylogenic tree was constructed and genetic distances were calculated using MEGA 3.1. Recombination analysis was done by bootscan using SimPlot software. Two hundred and twenty-three HIV-1-positive individuals were enrolled in the study. At baseline, the mean plasma viral load was 285,500 HIV-1 RNA copies/ml and the mean CD4 cell count was 213 cells/ml. Subtype B was found in 220 (98.6%) samples, whereas IRs were found in three patients (1.4%): two (0.9%) with BG and one (0.45%) with BF. IRs were observed in 2/124 (1.6%) samples from treated patients and in 1/99 (1.0%) from naive patients. The presence of these HIV forms at low frequency points to the need for research on the diversity, geographic distribution, and evolution of other subtypes including circulating recombinant forms and IRs to understand the molecular epidemiology and tendencies of the HIV infection in Mexico.