Contribution of the HIV-1 Envelope Glycoprotein to AIDS Pathogenesis and Clinical Progression

In the absence of antiviral therapy, HIV-1 infection progresses to a wide spectrum of clinical manifestations that are the result of an entangled contribution of host, immune and viral factors. The contribution of these factors is not completely established. Several investigations have described the involvement of the immune system in the viral control. In addition, distinct HLA-B alleles, HLA-B27, -B57-58, were associated with infection control. The combination of these elements and antiviral host restriction factors results in different clinical outcomes. The role of the viral proteins in HIV-1 infection has been, however, less investigated. We will review contributions dedicated to the pathogenesis of HIV-1 infection focusing on studies identifying the function of the viral envelope glycoprotein (Env) in the clinical progression because of its essential role in the initial events of the virus life-cycle. Some analysis showed that inefficient viral Envs were dominant in non-progressor individuals. These poorly-functional viral proteins resulted in lower cellular activation, viral replication and minor viral loads. This limited viral antigenic production allows a better immune response and a lower immune exhaustion. Thus, the properties of HIV-1 Env are significant in the clinical outcome of the HIV-1 infection and AIDS pathogenesis.This work was funded by the Spanish AIDS network “Red Temática Cooperativa de Investigación en SIDA” RD12/0017/0002, RD12/0017/0028, RD12/0017/0034, RD16/0025/0011, RDCIII16/0002/0005 and RD16/0025/0041 as part of the Plan Nacional R + D+I and co-funded by the Spanish “Instituto de Salud Carlos III (ISCIII)-Subdirección General de Evaluación y el Fondo Europeo de Desarrollo Regional (FEDER)”. J.B. is a researcher from “Fundació Institut de Recerca en Ciències de la Salut Germans Trias i Pujol” supported by the Health Department of the Catalonian Government/Generalitat de Catalunya and ISCIII grant Nos. PI17/01318 and PI20/00093 (to J.B.). Work in C.C. Lab was supported by grants SAF (2010-17226) and (2016-77894-R) from MINECO (Spain), FIS (PI13/02269, ISCIII) and PI20/00093. A.-V.F.’s Lab is supported by the European Regional Development Fund (ERDF), PID2021-123031OB-I00 (“Ministerio de Ciencia e Innovación”, Spain), RTI2018-093747-B-100 (“Ministerio de Ciencia, Innovación y Universidades”, Spain), ProID2020010093 (“Agencia Canaria de Investigación, Innovación y Sociedad de la Información” and the European Social Fund), UNLL10-3E-783 (ERDF and “Fundación CajaCanarias”) and “SEGAI-ULL”. S.-P.Y. is funded by “Fundación Doctor Manuel Morales” (La Palma, Spain) and “Contrato Pre-doctoral Ministerio-ULL Formación de Doctores” (2019 Program) (“Ministerio de Ciencia, Innovación y Universidades”, Spain). R.-C.R. is funded by RD16/0025/0011 and ProID2020010093 (“Agencia Canaria de Investigación, Innovación y Sociedad de la Información” and European Social Fund). J.-G.L. is funded by the “Juan de la Cierva de Incorporación” Spanish Program (IJC2019-038902-I) (“Ayudas Juan de la Cierva de incorporación; Agencia Estatal de Investigación. Ministerio de Ciencia e Innovación”).S

The Characteristics of the HIV-1 Env Glycoprotein Are Linked With Viral Pathogenesis

The understanding of HIV-1 pathogenesis and clinical progression is incomplete due to the variable contribution of host, immune, and viral factors. The involvement of viral factors has been investigated in extreme clinical phenotypes from rapid progressors to long-term non-progressors (LTNPs). Among HIV-1 proteins, the envelope glycoprotein complex (Env) has been concentrated on in many studies for its important role in the immune response and in the first steps of viral replication. In this study, we analyzed the contribution of 41 Envs from 24 patients with different clinical progression rates and viral loads (VLs), LTNP-Elite Controllers (LTNP-ECs); Viremic LTNPs (vLTNPs), and non-controller individuals contemporary to LTNPs or recent, named Old and Modern progressors. We studied the Env expression, the fusion and cell-to-cell transfer capacities, as well as viral infectivity. The sequence and phylogenetic analysis of Envs were also performed. In every functional characteristic, the Envs from subjects with viral control (LTNP-ECs and vLTNPs) showed significant lower performance compared to those from the progressor individuals (Old and Modern). Regarding sequence analysis, the variable loops of the gp120 subunit of the Env (i.e., V2, V4, and mainly V5) of the progressor individuals showed longer and more glycosylated sequences than controller subjects. Therefore, HIV-1 Envs from virus of patients presenting viremic control and the non-progressor clinical phenotype showed poor viral functions and shorter sequences, whereas functional Envs were associated with virus of patients lacking virological control and with progressor clinical phenotypes. These correlations support the role of Env genotypic and phenotypic characteristics in the in vivo HIV-1 infection and pathogenesis.This work is supported by Spanish AIDS network “Red Temática Cooperativa de Investigación en SIDA” RD12/0017/0002, RD12/0017/0028, RD12/0017/0034, RD16/0025/0011, RDCIII16/0002/0005, and RD16/0025/0041 as part of the Plan Nacional R + D + I and cofunded by Spanish “Instituto de Salud Carlos III (ISCIII)-Subdirección General de Evaluación y el Fondo Europeo de Desarrollo Regional (FEDER).” JB is a researcher from “Fundació Institut de Recerca en Ciències de la Salut Germans Trias i Pujol” supported by the Health Department of the Catalan Government/Generalitat de Catalunya and ISCIII grant numbers PI17/01318 and PI20/00093 (to JB). Work in CL-G and CC lab was supported by grants SAF (2010-17226) and (2016-77894-R) from MINECO (Spain) and FIS (PI 13/02269 and PI20/00093, ISCIII). AV-F’s Lab is supported by the European Regional Development Fund (ERDF), RTI2018-093747-B-100 (“Ministerio de Ciencia e Innovación,” Spain), “Ministerio de Ciencia, Innovación y Universidades” (Spain), ProID2020010093 (“Agencia Canaria de Investigación, Innovación y Sociedad de la Información” and European Social Fund), UNLL10-3E-783 (ERDF and “Fundación CajaCanarias”) and “SEGAI-ULL.” SP-Y is funded by “Fundación Doctor Manuel Morales” (La Palma, Spain) and “Contrato Predoctoral Ministerio-ULL Formación de Doctores” (2019 Program; “Ministerio de Ciencia, Innovación y Universidades,” Spain). RC-R is funded by RD16/0025/0011 and ProID2020010093 (“Agencia Canaria de Investigación, Innovación y Sociedad de la Información” and European Social Fund). JE-H is funded by the Cabildo Tenerife “Agustin de Betancourt” 2017 Program.S

HIV-1 Nef Targets HDAC6 to Assure Viral Production and Virus Infection

HIV Nef is a central auxiliary protein in HIV infection and pathogenesis. Our results indicate that HDAC6 promotes the aggresome/autophagic degradation of the viral polyprotein Pr55Gag to inhibit HIV-1 production. Nef counteracts this antiviral activity of HDAC6 by inducing its degradation and subsequently stabilizing Pr55Gag and Vif viral proteins. Nef appears to neutralize HDAC6 by an acidic/endosomal-lysosomal processing and does not need the downregulation function, since data obtained with the non-associated cell-surface Nef-G2A mutant – the cytoplasmic location of HDAC6 – together with studies with chemical inhibitors and other Nef mutants, point to this direction. Hence, the polyproline rich region P72xxP75 (69–77 aa) and the di-Leucin motif in the Nef-ExxxLL160-165 sequence of Nef, appear to be responsible for HDAC6 clearance and, therefore, required for this novel Nef proviral function. Nef and Nef-G2A co-immunoprecipitate with HDAC6, whereas the Nef-PPAA mutant showed a reduced interaction with the anti-HIV-1 enzyme. Thus, the P72xxP75 motif appears to be responsible, directly or indirectly, for the interaction of Nef with HDAC6. Remarkably, by neutralizing HDAC6, Nef assures Pr55Gag location and aggregation at plasma membrane, as observed by TIRFM, promotes viral egress, and enhances the infectivity of viral particles. Consequently, our results suggest that HDAC6 acts as an anti-HIV-1 restriction factor, limiting viral production and infection by targeting Pr55Gag and Vif. This function is counteracted by functional HIV-1 Nef, in order to assure viral production and infection capacities. The interplay between HIV-1 Nef and cellular HDAC6 may determine viral infection and pathogenesis, representing both molecules as key targets to battling HIV

HIV-1 envelope glycoproteins isolated from viremic non-progressor individuals are fully functional and cytopathic

International audienc

Transactive Response DNA-Binding Protein (TARDBP/TDP-43) Regulates Cell Permissivity to HIV-1 Infection by Acting on HDAC6

The transactive response DNA-binding protein (TARDBP/TDP-43) influences the processing of diverse transcripts, including that of histone deacetylase 6 (HDAC6). Here, we assessed TDP-43 activity in terms of regulating CD4+ T-cell permissivity to HIV-1 infection. We observed that overexpression of wt-TDP-43 increased both mRNA and protein levels of HDAC6, resulting in impaired HIV-1 infection independently of the viral envelope glycoprotein complex (Env) tropism. Consistently, using an HIV-1 Env-mediated cell-to-cell fusion model, the overexpression of TDP-43 levels negatively affected viral Env fusion capacity. Silencing of endogenous TDP-43 significantly decreased HDAC6 levels and increased the fusogenic and infection activities of the HIV-1 Env. Using pseudovirus bearing primary viral Envs from HIV-1 individuals, overexpression of wt-TDP-43 strongly reduced the infection activity of Envs from viremic non-progressors (VNP) and rapid progressors (RP) patients down to the levels of the inefficient HIV-1 Envs observed in long-term non-progressor elite controllers (LTNP-EC). On the contrary, silencing endogenous TDP-43 significantly favored the infectivity of primary Envs from VNP and RP individuals, and notably increased the infection of those from LTNP-EC. Taken together, our results indicate that TDP-43 shapes cell permissivity to HIV-1 infection, affecting viral Env fusion and infection capacities by altering the HDAC6 levels and associated tubulin-deacetylase anti-HIV-1 activity.This work is supported by the Spanish AIDS network “Red Temática Cooperativa de Investigación en SIDA” RD12/0017/0002, RD12/0017/0028, RD12/0017/0034, RD16/0025/0011, RDCIII16/0002/0005 and RD16/0025/0041 as part of the Plan Nacional R + D+I and co-funded by the Spanish “Instituto de Salud Carlos III (ISCIII)-Subdirección General de Evaluación y el Fondo Europeo de Desarrollo Regional (FEDER)”. J.B. is a researcher from “Fundació Institut de Recerca en Ciències de la Salut Germans Trias i Pujol” supported by the Health Department of the Catalonian Government/Generalitat de Catalunya and ISCIII grant numbers PI17/01318 and PI20/00093 (to J.B.). Work in CC Lab was supported by grants SAF (2010-17226) and (2016-77894-R) from MINECO (Spain), FIS (PI 13/02269, ISCIII) and PI20/00093. Work in CF Lab was supported by the Cabildo Insular de Tenerife (grants CGIEU0000219140 and “Apuestas científicas del ITER para colaborar en la lucha contra la COVID-19”); the agreement with the Instituto Tecnológico y de Energías Renovables (ITER) to strengthen scientific and technological education, training research, development and innovation in Genomics, Personalized Medicine and Biotechnology (grant number OA17/008). A.V.-F.’s Lab is supported by the European Regional Development Fund (ERDF), RTI2018-093747-B-100 (“Ministerio de Ciencia e Innovación”, Spain), “Ministerio de Ciencia, Innovación y Universidades” (Spain), ProID2020010093 (“Agencia Canaria de Investigación, Innovación y Sociedad de la Información” and European Social Fund), UNLL10-3E-783 (ERDF and “Fundación CajaCanarias”) and “SEGAI-ULL”. S.P-Y is funded by “Fundación Doctor Manuel Morales” (La Palma, Spain) and “Contrato Predoctoral Ministerio-ULL Formación de Doctores” (2019 Program) (“Ministerio de Ciencia, Innovación y Universidades”, Spain). R.C.-R. is funded by RD16/0025/0011 and ProID2020010093 (“Agencia Canaria de Investigación, Innovación y Sociedad de la Información” and European Social Fund). J.G.-L. is funded by the “Juan de la Cierva de Incorporación” Spanish Program (IJC2019-038902-I) (“Ayudas Juan de la Cierva de incorporación; Agencia Estatal de Investigación. Ministerio de Ciencia e Innovación”).S

Stable neutralizing antibody levels 6 months after mild and severe COVID-19 episodes

Background. Understanding mid-term kinetics of immunity to SARS-CoV-2 is the cornerstone for public health control of the pandemic and vaccine development. However, current evidence is rather based on limited measurements, losing sight of the temporal pattern of these changes. Methods. We conducted a longitudinal analysis on a prospective cohort of COVID-19 patients followed up for >6 months. Neutralizing activity was evaluated using HIV reporter pseudoviruses expressing SARS-CoV-2 S protein. IgG antibody titer was evaluated by ELISA against the S2 subunit, the receptor binding domain (RBD), and the nucleoprotein (NP). Statistical analyses were carried out using mixed-effects models. Findings. We found that individuals with mild or asymptomatic infection experienced an insignificant decay in neutralizing activity, which persisted 6 months after symptom onset or diagnosis. Hospitalized individuals showed higher neutralizing titers, which decreased following a 2-phase pattern, with an initial rapid decline that significantly slowed after day 80. Despite this initial decay, neutralizing activity at 6 months remained higher among hospitalized individuals compared to mild symptomatic. The slow decline in neutralizing activity at mid-term contrasted with the steep slope of anti-RBD, S2, or NP antibody titers, all of them showing a constant decline over the follow-up period. Conclusions. Our results reinforce the hypothesis that the quality of the neutralizing immune response against SARS-CoV-2 evolves over the post-convalescent stage.info:eu-repo/semantics/acceptedVersio

TDP-43 Controls HIV-1 Viral Production and Virus Infectiveness

The transactive response DNA-binding protein (TARDBP/TDP-43) is known to stabilize the anti-HIV-1 factor, histone deacetylase 6 (HDAC6). TDP-43 has been reported to determine cell permissivity to HIV-1 fusion and infection acting on tubulin-deacetylase HDAC6. Here, we studied the functional involvement of TDP-43 in the late stages of the HIV-1 viral cycle. The overexpression of TDP-43, in virus-producing cells, stabilized HDAC6 (i.e., mRNA and protein) and triggered the autophagic clearance of HIV-1 Pr55Gag and Vif proteins. These events inhibited viral particle production and impaired virion infectiveness, observing a reduction in the amount of Pr55Gag and Vif proteins incorporated into virions. A nuclear localization signal (NLS)-TDP-43 mutant was not able to control HIV-1 viral production and infection. Likewise, specific TDP-43-knockdown reduced HDAC6 expression (i.e., mRNA and protein) and increased the expression level of HIV-1 Vif and Pr55Gag proteins and α-tubulin acetylation. Thus, TDP-43 silencing favored virion production and enhanced virus infectious capacity, thereby increasing the amount of Vif and Pr55Gag proteins incorporated into virions. Noteworthy, there was a direct relationship between the content of Vif and Pr55Gag proteins in virions and their infection capacity. Therefore, for TDP-43, the TDP-43/HDAC6 axis could be considered a key factor to control HIV-1 viral production and virus infectiveness

Zika Virus Pathogenesis: A Battle for Immune Evasion

Zika virus (ZIKV) infection and its associated congenital and other neurological disorders, particularly microcephaly and other fetal developmental abnormalities, constitute a World Health Organization (WHO) Zika Virus Research Agenda within the WHO’s R&D Blueprint for Action to Prevent Epidemics, and continue to be a Public Health Emergency of International Concern (PHEIC) today. ZIKV pathogenicity is initiated by viral infection and propagation across multiple placental and fetal tissue barriers, and is critically strengthened by subverting host immunity. ZIKV immune evasion involves viral non-structural proteins, genomic and non-coding RNA and microRNA (miRNA) to modulate interferon (IFN) signaling and production, interfering with intracellular signal pathways and autophagy, and promoting cellular environment changes together with secretion of cellular components to escape innate and adaptive immunity and further infect privileged immune organs/tissues such as the placenta and eyes. This review includes a description of recent advances in the understanding of the mechanisms underlying ZIKV immune modulation and evasion that strongly condition viral pathogenesis, which would certainly contribute to the development of anti-ZIKV strategies, drugs, and vaccines.Depto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEpu

Epigenetic programming at the Mogat1 locus may link neonatal overnutrition with long-term hepatic steatosis and insulin resistance

Postnatal overfeeding increases the risk of chronic diseases later in life, including obesity, insulin resistance, hepatic steatosis, and type 2 diabetes. Epigenetic mechanisms might underlie the long-lasting effects associated with early nutrition. Here we aimed to explore the molecular pathways involved in early development of insulin resistance and hepatic steatosis, and we examined the potential contribution of DNA methylation and histone modifications to long-term programming of metabolic disease. We used a well-characterized mouse model of neonatal overfeeding and early adiposity by litter size reduction. Neonatal overfeeding led to hepatic insulin resistance very early in life that persisted throughout adulthood despite normalizing food intake. Up-regulation of monoacylglycerol O-acyltransferase (Mogat)1 conceivably mediates hepatic steatosis and insulin resistance through increasing intracellular diacylglycerol content. Early and sustained deregulation of Mogat1 was associated with a combination of histone modifications that might favor Mogat1 expression. In sum, postnatal overfeeding causes extremely rapid derangements of hepatic insulin sensitivity that remain relatively stable until adulthood. Epigenetic mechanisms, particularly histone modifications, could contribute to such long-lasting effects. Our data suggest that targeting hepatic monoacylglycerol acyltransferase activity during early life might provide a novel strategy to improve hepatic insulin sensitivity and prevent late-onset insulin resistance and fatty liver disease.Ramon-Krauel, M., Pentinat, T., Bloks, V. W., Cebria, J., Ribo, S., Perez-Wienese, R., Vila, M., Palacios-Marin, I., Fernandez-Perez, A., Vallejo, M., Tellez, N., Rodriguez, M. ., Yanes, O., Lerin, C., Diaz, R., Plosch, T., Tietge, U. J. F., Jimenez-Chillaron, J. C. Epigenetic programming at the Mogat1 locus may link neonatal overnutrition with long-term hepatic steatosis and insulin resistance

Epigenetic loss of the endoplasmic reticulum-associated degradation inhibitor SVIP induces cancer cell metabolic reprogramming

The endoplasmic reticulum (ER) of cancer cells needs to adapt to the enhanced proteotoxic stress associated with the accumulation of unfolded, misfolded and transformation-associated proteins. One way by which tumors thrive in the context of ER stress is by promoting ER-Associated Degradation (ERAD), although the mechanisms are poorly understood. Here, we show that the Small p97/VCP Interacting Protein (SVIP), an endogenous inhibitor of ERAD, undergoes DNA hypermethylation-associated silencing in tumorigenesis to achieve this goal. SVIP exhibits tumor suppressor features and its recovery is associated with increased ER stress and growth inhibition. Proteomic and metabolomic analyses show that cancer cells with epigenetic loss of SVIP are depleted in mitochondrial enzymes and oxidative respiration activity. This phenotype is reverted upon SVIP restoration. The dependence of SVIP hypermethylated cancer cells on aerobic glycolysis and glucose was also associated with sensitivity to an inhibitor of the glucose transporter GLUT1. This could be relevant to the management of tumors carrying SVIP epigenetic loss, because these occur in high-risk patients who manifest poor clinical outcomes. Overall, our study provides insights into how epigenetics helps deal with ER stress and how SVIP epigenetic loss in cancer may be amenable to therapies that target glucose transporters.This work was supported by the Health Department PERIS project number SLT/002/16/00374 and AGAUR project numbers 2017SGR1080, 2014SGR633, 2017SGR1033, and 2009SGR1315 of the Catalan Government (Generalitat de Catalunya); the Spanish Institute of Health Carlos III (ISCIII) project number DTS16/00153 and Ministerio de Economía y Competitividad (MINECO) project numbers SAF2014-55000-R, BFU2014-57466-P, SAF2017-89673-R, and SAF2015-70270-REDT co-financed by the European Development Regional Fund, A way to achieve Europe ERDF; the Cellex Foundation; and “la Caixa” Bank Foundation (LCF/PR/PR15/11100003). MC acknowledges the prize “ICREA Academia” for excellence in research, funded by ICREA foundation. We thank the Scientific and Technological Centre (CCiTUB) of the University of Barcelona for technical support with cell cytometry and sorting. We also thank the Regenerative Medicine Center (CMRB) Electron Microscopy and Histology facility