The ecto-enzyme CD38 modulates CD4 T cell immunometabolic responses and participates in HIV pathogenesis.

Despite abundant evidence correlating T cell CD38 expression and HIV infection pathogenesis, its role as a CD4 T cell immunometabolic regulator remains unclear. We find that CD38's extracellular glycohydrolase activity restricts metabolic reprogramming after TCR-engaging stimulation in Jurkat T CD4 cells, together with functional responses, while reducing intracellular NAD and NMN concentrations. Selective elimination of CD38's ectoenzyme function licenses them to decrease the OCR/ECAR ratio upon TCR signaling and to increase cycling, proliferation, survival, and CD40L induction. Pharmacological inhibition of ectoCD38 catalytic activity in memory CD4 T cells from chronic HIV-infected patients rescued TCR-triggered responses, including differentiation and effector functions, while reverting abnormally increased basal glycolysis, cycling, and spontaneous pro-inflammatory cytokine production. Additionally, ecto-CD38 blockage normalized basal and TCR-induced mitochondrial morpho-functionality, while increasing respiratory capacity in cells from HIV+ patients and healthy individuals. Ectoenzyme CD38's immunometabolic restriction of TCR-involving stimulation is relevant to CD4 T cell biology and to the deleterious effects of CD38 overexpression in HIV disease.

Erk1/2 signaling mediates the HGF-induced protection against ethanol and acetaldehyde-induced toxicity in the pancreatic RINm5F cell line.

Alcohol-induced pancreas damage remains as one of the main risk factors for pancreatitis development. This disorder is poorly understood, particularly the effect of acetaldehyde, the primary alcohol metabolite, in the endocrine pancreas. Hepatocyte growth factor (HGF) is a protective protein in many tissues, displaying antioxidant, antiapoptotic, and proliferative responses. In the present work, we were focused on characterizing the response induced by HGF and its protective mechanism in the RINm5F pancreatic cell line treated with ethanol and acetaldehyde. RINm5F cells were treated with ethanol or acetaldehyde for 12 h in the presence or not of HGF (50 ng/ml). Cells under HGF treatment decreased the content of reactive oxygen species and lipid peroxidation induced by both toxics, improving cell viability. This effect was correlated to an improvement in insulin expression impaired by ethanol and acetaldehyde. Using a specific inhibitor of Erk1/2 abrogated the effects elicited by the growth factor. In conclusion, the work provides mechanistic evidence of the HGF-induced-protective response to the alcohol-induced damage in the main cellular component of the endocrine pancreas.

Exceptional T CD4+ Recovery Post-antiretroviral Is Linked to a Lower HIV Reservoir with a Specific Immune Differentiation Pattern.

We present a cohort of individuals who reached CD4+ T cell counts of greater than 1,000 cells/mm3 (Hypers) after starting antiretroviral treatment (ART) and compared them with those who reached between 350 and 999 CD4+ T cells/mm3 (Concordants). Demographic data, immune recovery kinetics, T CD4+ subset phenotypes, and integrated HIV DNA were analyzed. Data from individuals living with HIV on their first ART regimen and after 48 months of follow-up were obtained. Immune phenotype by Flow Cytometry analysis on whole blood was performed, cytokines were measured, and integrated HIV-1 DNA was measured by polymerase chain reaction. From a total of 424 individuals, 26 Hypers (6.1%), 314 Concordants (74.1%), and 84 (19.8%) discordants were identified. Hypers had a higher proportion of CD4+-naive (Nv) T cells (37.6 vs. 24.8, p < .05), and a low proportion of CD4+ effector memory T cells (27.9 vs. 39.4, p < .05), with similar results found in CD8+ T cells. Hypers demonstrated a higher percentage of CD4+CD45RA+CD31neg cells with a lower response to interleukin-2 stimulation and a lower integrated HIV-1 DNA/CD4 ratio (1.2 vs. 2.89, p < .05). In Hypers, T cell recovery occurs very early after initiation of ART. Following this initial recovery state, their CD4+ T cell level homeostasis seems to be driven by nonthymic-central-Nv cells. This exceptional recovery is associated with a lower HIV reservoir, which may be related to an increase in noninfected CD4+ T cells. These patients could then be eligible candidates for cure trials.

Persistent high levels of immune activation and their correlation with the HIV-1 proviral DNA and 2-LTR circles loads, in a cohort of Mexican individuals following long-term and fully suppressive treatment.

OBJECTIVES: The aim of this study was to investigate the correlation between the HIV-1 reservoir and the levels of immune activation in chronic patients under fully suppressive cART. METHODS: We quantified the HIV proviral DNA and 2-LTR circles loads from PBMCs, the levels of CD38+ and Ki-67+ T-cells, and the levels of IL-7 in a cohort of patients with more than 5 years of ART at enrollment and after 1 year. RESULTS: In 29 participants with a median of 8 years (IQR, 6.9-9.4) under suppressive cART we found higher levels of CD8+ CD38+ T-cells after 1-year (P = .000). There was a non-statistically significant poor correlation between the levels of immune activation and the proviral DNA of CD4+ and CD8+ T-cells. Ki-67+ T-cells declined without significant differences, and there was no significant correlation with the proportion of CD38+. IL-7 decreased at the follow-up observation (P = .094), but there was no correlation with the levels of CD38+ and Ki-67+ T-cells. CONCLUSIONS: We found a weak but non-statistically significant correlation of the levels of T-cell activation with the proviral DNA and 2-LTR circles. This suggests the likely occurrence of further mechanisms driving chronic versus early immune activation other than viral replication by itself in chronic patients.

Regulation of Cas9 by viral proteins Tat and Rev for HIV-1 inactivation.

While combined antiretroviral therapy (cART) has had a great impact on the treatment of HIV-1 infection, the persistence of long-lived cells with an intact provirus precludes virus eradication and sterilizing cure. CRISPR/Cas9 genome editing has become an efficient tool to eradicate HIV-1 genome or prevent replication. Furthermore, regulation of Cas9 gene expression by HIV can induce mutations that could inactivate the proviral genome, making a gene therapy safe by preventing the induction of non-specific mutations, which could compromise the integrity of healthy cells. In this study, isolated HIV-1 LTR, INS and RRE sequences were used to regulate Cas9 expression in HEK293 cells, and guide RNAs (gRNAs) were designed to target mutations in HIV-1 conserved regions such as tat and rev regulatory genes. We demonstrate that Cas9 expression in our system is controlled by the HIV-1 Tat and Rev proteins, leading to self-regulation of gene edition, and showing a strong antiviral effect by inactivating HIV-1 replication. Sequencing analysis confirmed that viral genome was partially excised by multiplex editing (90% efficiency), and viral capsid protein (CA-p24) was undetectable. In conclusion, the self-regulated CRISPR/Cas9 system may be a reliable and accurate strategy for eliminating HIV-1 infection whose effect will be restricted to infected cells.