1,720,986 research outputs found
Autophagy modulation in mammarenavirus infection
Get PDFMammarenavirus genus groups viruses causing human haemorrhagicdiseases, including the New World (NW) Junín virus (JUNV), and the Old World(OW) viruses Lassa (LASV), among others. The high mortality and morbidityrates associated to pathogenic mammarenaviruses, the absence of vaccinesand the constant threat of new emerging species, make these viruses a publichealth concern in endemic areas. Autophagy is a widely-known intracellularmetabolic pathway involved in maintaining the cellular homeostasis inresponse to several stress conditions.Fil: Gallo, Giovanna Lucrecia. Ministerio de Producción y Trabajo. Secretaría de Gobierno de Agroindustria. Servicio Nacional de Sanidad y Calidad Agroalimentaria. Centro de Virología Animal. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Virología Animal; ArgentinaFil: Roldán, Julieta S.. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Delgui, Laura Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentin
The endosomal pathway and the Golgi complex are involved in the Infectious bursal disease virus life cycle.
Get PDFInfectious bursal disease virus (IBDV), a double-stranded RNA virus belonging to the Birnaviridae family, causes immunosuppression in chickens. In this study, we defined the localization of IBDV replication complexes based on colocalization analysis of VP3, the major protein component of IBDV ribonucleoproteins (RNPs). Our results indicate that VP3 localizes to vesicular structures bearing features of early and late endocytic compartments located in the juxtanuclear region. Interfering with the endocytic pathway with a dominant negative version of Rab5 after the internalization step leads to a reduction in virus titer. Triple-immunostaining studies between VP3, the viral RNA-dependent RNA polymerase VP1, and viral double-stranded RNA (dsRNA) showed a well-defined colocalization, indicating that the three critical components of the RNPs colocalize in the same structure, likely representing replication complexes. Interestingly, recombinant expressed VP3 also localizes to endosomes. Employing Golgi markers, we found that VP3-containing vesicles were closely associated with this organelle. Depolymerization of microtubules with nocodazole caused a profound change in VP3 localization, showing a punctate distribution scattered throughout the cytoplasm. However, these VP3-positive structures remained associated with Golgi ministacks. Similarly, brefeldin A (BFA) treatment led to a punctate distribution of VP3, scattered throughout the cytoplasm of infected cells. In addition, analysis of intra- and extracellular viral infective particles after BFA treatment of avian cells suggested a role for the Golgi complex in viral assembly. These results constitute the first study elucidating the localization of IBDV replication complexes (i.e., in endocytic compartments) and establishing a role for the Golgi apparatus in the assembly step of a birnavirus.Fil: Delgui, Laura Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; ArgentinaFil: Rodriguez, José F.. Consejo Superior de Investigaciones Cientificas. Centro Nacional de Biotecnologia; EspañaFil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina; Argentina; Argentin
A Novel Mechanism Underlying the Innate Immune Response Induction upon Viral-Dependent Replication of Host Cell mRNA: A Mistake of +sRNA Viruses' Replicases
Get PDFViruses are lifeless particles designed for setting virus-host interactome assuring a new generation of virions for dissemination. This interactome generates a pressure on host organisms evolving mechanisms to neutralize viral infection, which places the pressure back onto virus, a process known as virus-host cell co-evolution. Positive-single stranded RNA (+sRNA) viruses are an important group of viral agents illustrating this interesting phenomenon. During replication, their genomic +sRNA is employed as template for translation of viral proteins; among them the RNA-dependent RNA polymerase (RdRp) is responsible of viral genome replication originating double-strand RNA molecules (dsRNA) as intermediates, which accumulate representing a potent threat for cellular dsRNA receptors to initiate an antiviral response. A common feature shared by these viruses is their ability to rearrange cellular membranes to serve as platforms for genome replication and assembly of new virions, supporting replication efficiency increase by concentrating critical factors and protecting the viral genome from host anti-viral systems. This review summarizes current knowledge regarding cellular dsRNA receptors and describes prototype viruses developing replication niches inside rearranged membranes. However, for several viral agents it's been observed both, a complex rearrangement of cellular membranes and a strong innate immune antiviral response induction. So, we have included recent data explaining the mechanism by, even though viruses have evolved elegant hideouts, host cells are still able to develop dsRNA receptors-dependent antiviral response.Fil: Delgui, Laura Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin
Autophagy as an innate immunity response against pathogens: a Tango dance
Get PDFIntracellular infections as well as changes in the cell nutritional environmentare main events that trigger cellular stress responses. One crucial cellresponse to stress conditions is autophagy. During the last 30 years, severalscenarios involving autophagy induction or inhibition over the course of anintracellular invasion by pathogens have been uncovered. In this review, wewill present how this knowledge was gained by studying different microorganisms.We intend to discuss how the cell, via autophagy, tries to repel theseattacks with the objective of destroying the intruder, but also how some pathogenshave developed strategies to subvert this. These two fates can be comparedwith a Tango, a dance originated in Buenos Aires, Argentina, in whichthe partner dancers are in close connection. One of them is the leader,embracing and involving the partner, but the follower may respond escapingfrom the leader. This joint dance is indeed highly synchronized and controlled,perfectly reflecting the interaction between autophagy and microorganism.Fil: Aguilera, Milton Osmar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Delgui, Laura Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Reggiori, Fulvio. University Aarhus; DinamarcaFil: Romano, Patricia Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin
Inhibition of autophagy caused by human cytomegalovirus : physiopathological role in the context of epithelial renal cells
Get PDFLa vía de la autofagia es un proceso catabólico celular altamente regulado implicado en numerosos mecanismos fisiológicos y fisiopatológicos. Durante los últimos años, un creciente número de estudios demostró que diversos virus pueden modular la autofagia en beneficio de su replicación. El Cytomegalovirus Humano (HCMV) es el miembro prototipo de los β-herpesvirus y un patógeno oportunista generalizado. La infección por HCMV es una causa importante de morbilidad y mortalidad en individuos inmunocomprometidos. Así, los receptores de trasplantes que reciben terapia inmunosupresora tienen un mayor riesgo de infección y enfermedad por HCMV. Como resultado, la infección por HCMV representa una complicación importante en los pacientes que reciben trasplantes de órganos sólidos, incluidos los receptores de riñón.Resultados del grupo de Audrey ESCLATINE y de otros autores demostraron que el HCMV modula la autofagia durante la infección. Así, se ha observado que la infección por HCMV induce la autofágia independientemente de la síntesis de proteínas virales durante las primeras etapas de la infección, mientras que en etapas posteriores de la infección, el virus puede inhibir el flujo de autofágia, secuestrando parte de la maquinaria de autofagia para su replicación. Con el fin de conectar nuestras observaciones previas a la fisiopatología de las infecciones por HCMV in vivo, decidimos centrarnos en las infecciones renales por HCMV. Nuestra hipótesis es que la inhibición de la autofágia mediada por el HCMV en las células epiteliales renales conduce a la pérdida de la función de las células renales. Nuestra propuesta, dado que se ha originado en el contexto de la colaboración con la Dra. ESCLATINE, incluye dos objetivos amplios a desarrollar en nuestro laboratorio del IHEM-CONICET-UNCuyo y en el de la Dra. ESCLATINE en la Université París Sud, (París, Francia), respectivamente. Así, nuestros objetivos son: i) Caracterizar la inhibición de la autofagia inducido por la infección en un modelo celular renal (IHEM) y ii) Obtener aislamientos virales de HCMV provenientes de pacientes con infección productiva de HCMV post-trasplante de riñón (IHEM - Hospital Central - Mendoza). Nuestros hallazgos podrían proporcionar evidencia in vitro de un mecanismo patogénico que explique la asociación clínica entre la infección por HCMV, la inhibición de la autofagia y el devenir adverso del injerto renal.The autophagy pathway is a highly regulated cellular catabolic process involved in numerous physiological and pathophysiological mechanisms. During recent years, a growing number of studies have shown that several viruses are able to modulate autophagy for the success of replication. The Human Cytomegalovirus (HCMV) is the prototype member of the β-herpesvirus and a generalized opportunistic pathogen. HCMV infection is an important cause of morbidity and mortality in immunocompromised individuals. Thus, transplant recipients receiving immunosuppressive therapy have an increased risk of HCMV infection and disease. As a result, HCMV infection represents a major complication in patients receiving solid organ transplants, including kidney recipients.Results from the Audrey ESCLATINE group and other authors showed that HCMV modulates autophagy during infection. Thus, it has been observed that HCMV infection induces autophagy regardless of the synthesis of viral proteins during the early stages of infection, while in later stages of infection, the virus can inhibit the autophagy flux, hijacking part of the autophagy machinery for its replication.In order to connect our previous observations to the pathophysiology of HCMV infections in vivo, we decided to focus on renal infections caused by HCMV. Our hypothesis is that the inhibition of autophagy mediated by HCMV in renal epithelial cells leads to loss of renal cell function. Our proposal, given that it was originated in the context of a collaboration with Dr. ESCLATINE, includes two broad objectives to be developed in our laboratory at IHEM-CONICET-UNCuyo and in that of Dr. ESCLATINE at Université Paris Sud, ( Paris, France), respectively. Thus, our objectives are: i) To characterize the inhibition of autophagy induced by infection in a renal cellular model (IHEM) and ii) To obtain viral isolates of HCMV from patients with productive HCMV infection after kidney transplantation (IHEM - Central Hospital - Mendoza). Our findings could provide in vitro evidence of a pathogenic mechanism that explains the clinical association between HCMV infection, the inhibition of autophagy and the adverse development of renal graft
Identificación del receptor de adhesión del virus de la bursitis infecciosa
No full textTesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 30-05-2008Infectious bursal disease virus (IBDV), a non-enveloped, double-stranded RNA (dsRNA) virus that belongs to the family Birnaviridae, is an important avian pathogen. The first step in the life cycle of non-enveloped viruses involves the recognition and attachment of the viral capsid to an appropriate cell membrane receptor(s). Elucidation of the viral and cellular components of this initial interaction might provide new clues for the development of effective anti-IBDV agents, vaccine design, and the generation of new biotechnological tools.
The IBDV capsid is a single-shelled T=13 icosahedral lattice built by 780 protruding subunits, organized in 260 trimers, formed by a single polypeptide termed VP2. The VP2 protein is thus responsible for the the attachment of the virus to the cell surface. In general terms, this step is considered as a major determinant for virus host-range and pathogenesis.
Analysis of the VP2 sequence revealed the presence of the integrin-ligand motif “IDA”, located at the base of the VP2 projection domain (residues 234-236). This motif is the minimal essential sequence for the adhesion of fibronectin to the α4β1 integrin (Komoriya y col. 1991). The use of genetically modified IBDV-derived subviral particles (SVPs), allowed us to demonstrate the critical role of the described motif on the attachment of the virus to IBDV-susceptible cells. We have shown that mutant SVPs harbouring a single substitution on this motif (D235A) completely abrogates the attachment of SVPs to chicken embryo fobroblasts. Cryo-electron microscopy and three-dimensional reconstruction of mutant SVPs (D235A) confirmed that the observed effect is genuinely due to the mutation of the aspartic acid, since the overall organization of the mutated SVP is identical to that of the wild type one.
Additionally, results obtained with α4-negative and α4-positive murine fibroblast BALB/c 3T3-derived cell lines demonstrate that both IBDV attachment and susceptibility to IBDV-infection is dependent upon the presence on the cell surface of the α4β1 integrin. These results were confirmed using anti-α4 and -β1 function-blocking antibodies.
Taken together, our data demonstrate that, in the cell lines analysed in this study, the attachment of IBDV requires the interaction between the VP2 “IDA” motif and the α4β1 integrin, and that this interaction is essential for IBDV infectivity
Infectious bursal disease virus uptake involves macropinocytosis and trafficking to early endosomes in a Rab5-dependent manner
Get PDFInfectious bursal disease virus (IBDV) internalization is sparsely known in terms of molecular components of the pathway involved. To describe the cell biological features of IBDV endocytosis, we employed perturbants of endocytic pathways such as pharmacological inhibitors and overexpression of dominant-negative mutants. Internalization analysis was performed quantifying infected cells by immunofluorescence and Western blot detection of the viral protein VP3 at 12 h post-infection reinforced by the analysis of the capsid protein VP2 localization after virus uptake at 1 h post-infection. We compared IBDV infection to the internalization of well-established ligands with defined endocytic pathways: transferrin, cholera-toxin subunit B and dextran. To describe virus endocytosis at the morphological level, we performed ultrastructural studies of viral internalization kinetics in control and actin dynamics-blocked cells. Our results indicate that IBDV endocytic internalization was clathrin- and dynamin-independent, and that IBDV uses macropinocytosis as the primary entry mechanism. After uptake, virus traffics to early endosomes and requires exposure to the low endocytic pH as well as a functional endocytic pathway to complete its replication cycle. Moreover, our results indicate that the GTPase Rab5 is crucial for IBDV entry supporting the participation of the early endosomal pathway in IBDV internalization and infection of susceptible cells.Fil: Gimenez, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad "Juan Agustín Maza"; ArgentinaFil: Rodríguez Aguirre, José F.. Consejo Superior de Investigaciones Científicas. Centro Nacional de Biotecnología; EspañaFil: Colombo, Maria Isabel. Universidad "Juan Agustín Maza"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Delgui, Laura Ruth. Universidad "Juan Agustín Maza"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentin
Assesing the effect of Ursolic Acid on Lipid Droplet biogenesis using a Langmuir model system
No full textAccording to the latest Lipid Droplet (LD) biogenesis models, interfacial tension plays a critical role on such process, determining the shape of the budding LD from the ER. We have previously presented triglyceride (TG) “lenses” at the air-water interface as a model system for studying LD biogenesis. The performance of Langmuir monolayers of mixed phosphatidylcholine (EPC)/TG in coexistence with TG microlenses (i.e. an excluded TG phase floating in the surface) and the characterization of their lenses´ thickness by Brewster Angle Microscopy (BAM) allow evaluating the proneness of TG lenses to form a LD. This is done by characterizing the associated thermodynamics and the resulting shape of the TG lenses. Here, we evaluated the modulation of TG lenses tendency to detach from the interface by the presence of a third component with interfacial activity. For this purpose, we choose Ursolic Acid (UA), a natural pentacyclic triterpenoid with many biological effects and a clear interfacial activity. We found that UA slightly diminished the surface pressure at which TG phase separation occurs (i.e., lenses appearance) in composition dependent manner (both %UA and PC/TG relation). Such effect may be correlated with the dependency of UA interfacial partitioning on lipid composition. On the other hand, BAM analysis showed a lower reflectivity of lenses in the presence of UA. Assuming a negligible effect of UA on the refractive index of TG lenses, this implies a thinning of such structures. Additionally, the decreased radii of lenses observed allowed us concluding that the contact angle of the lenses is lower in the presence of UA. In conclusion, this experimental model allowed the detection of an interfacial active compound, like UA, affecting both the energy necessary to form the TG lenses and its shape, leading to structures of lower curvature and radii. These results are in accordance with observed effects of UA on LD in cells: a decrease in LD number and radii.Fil: Caruso, Benjamin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Tohmé Chapini, María Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Wilke, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Delgui, Laura Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaXLVIII Reunion Anual de la Sociedad Argentina de BiofisicaSan LuisArgentinaSociedad Argentina de Biofísic
Phosphatidylinositol 3-phosphate mediates the establishment of infectious bursal disease virus replication complexes in association with early endosomes
Get PDFInfectious bursal disease virus (IBDV) is the archetypal member of the family Birnaviridae and the etiological agent of Gumboro disease, a highly contagious immunosuppressive infection of concern to the global poultry sector for its adverse health effects in chicks. Unlike most double-stranded RNA (dsRNA) viruses, which enclose their genomes within specialized cores throughout their viral replication cycle, birnaviruses organize their bisegmented dsRNA genome in ribonucleoprotein (RNP) structures. Recently, we demonstrated that IBDV exploits endosomal membranes for replication. The establishment of IBDV replication machinery on the cytosolic leaflet of endosomal compartments is mediated by the viral protein VP3 and its intrinsic ability to target endosomes. In this study, we identified the early endosomal phosphatidylinositol 3-phosphate [PtdIns(3)P] as a key host factor of VP3 association with endosomal membranes and consequent establishment of IBDV replication complexes in early endosomes. Indeed, our data reveal a crucial role for PtdIns(3)P in IBDV replication. Overall, our findings provide new insights into the replicative strategy of birnaviruses and strongly suggest that it resembles those of positive-strand RNA (1ssRNA) viruses, which replicate in association with host membranes. Furthermore, our findings support the role of birnaviruses as evolutionary intermediaries between 1ssRNA and dsRNA viruses and, importantly, demonstrate a novel role for PtdIns(3)P in the replication of a dsRNA virus. IMPORTANCE Infectious bursal disease virus (IBDV) infects chicks and is the causative agent of Gumboro disease. During IBDV outbreaks in recent decades, the emergence of very virulent variants and the lack of effective prevention/treatment strategies to fight this disease have had devastating consequences for the poultry industry. IBDV belongs to the peculiar family Birnaviridae. Unlike most dsRNA viruses, birnaviruses organize their genomes in ribonucleoprotein complexes and replicate in a core-independent manner. We recently demonstrated that IBDV exploits host cell endosomes as platforms for viral replication, a process that depends on the VP3 viral protein. In this study, we delved deeper into the molecular characterization of IBDV-endosome association and investigated the role of host cell phosphatidylinositide lipids in VP3 protein localization and IBDV infection. Together, our findings demonstrate that PtdIns(3)P serves as a scaffold for the association of VP3 to endosomes and reveal its essential role for IBDV replication.Fil: Gimenez, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. University of Toronto; CanadáFil: Issa, Mariam. University of Toronto; CanadáFil: Sheth, Javal. University of Toronto; CanadáFil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Terebiznik, Mauricio R.. University of Toronto; CanadáFil: Delgui, Laura Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin
Junín virus promotes autophagy to facilitate the virus life cycle
Get PDFJunín virus (JUNV), a member of the family Arenaviridae, is the etiological agent of Argentine hemorrhagic fever (AHF), a potentially deadly endemic-epidemic disease affecting the population of the most fertile farming land of Argentina. Autophagy is a degradative process with a crucial antiviral role; however, several viruses subvert the pathway to their benefit. We determined the role of autophagy in JUNV-infected cells by analyzing LC3, a cytoplasmic protein (LC3-I) that becomes vesicle membrane associated (LC3-II) upon induction of autophagy. Cells overexpressing enhanced green fluorescent protein (EGFP)-LC3 and infected with JUNV showed an increased number of LC3 punctate structures, similar to those obtained after starvation or bafilomycin A1 treatment, which leads to autophagosome induction or accumulation, respectively. We also monitored the conversion of LC3-I to LC3-II, observing LC3-II levels in JUNV-infected cells similar to those observed in starved cells. Additionally, we kinetically studied the number of LC3 dots after JUNV infection and found that the virus activated the pathway as early as 2 h postinfection (p.i.), whereas the UV-inactivated virus did not induce the pathway. Cells subjected to starvation or pretreated with rapamycin, a pharmacological autophagy inductor, enhanced virus yield. Also, we assayed the replication capacity of JUNV in Atg5 knockout or Beclin 1 knockdown cells (both critical components of the autophagic pathway) and found a significant decrease in JUNV replication. Taken together, our results constitute the first study indicating that JUNV infection induces an autophagic response, which is functionally required by the virus for efficient propagation. IMPORTANCE Mammalian arenaviruses are zoonotic viruses that cause asymptomatic and persistent infections in their rodent hosts but may produce severe and lethal hemorrhagic fevers in humans. Currently, there are neither effective therapeutic options nor effective vaccines for viral hemorrhagic fevers caused by human-pathogenic arenaviruses, except the vaccine Candid no. 1 against Argentine hemorrhagic fever (AHF), licensed for human use in areas of endemicity in Argentina. Since arenaviruses remain a severe threat to global public health, more in-depth knowledge of their replication mechanisms would improve our ability to fight these viruses. Autophagy is a lysosomal degradative pathway involved in maintaining cellular homeostasis, representing powerful anti-infective machinery. We show, for the first time for a member of the family Arenaviridae, a proviral role of autophagy in JUNV infection, providing new knowledge in the field of host-virus interaction. Therefore, modulation of virus-induced autophagy could be used as a strategy to block arenavirus infections.Fil: Roldan, Julieta Suyay. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Candurra, Nélida Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Virología; ArgentinaFil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Delgui, Laura Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin
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