Biology subjects

Bellomo, C.

Publications and source records attributed to Bellomo, C..

3 recordsLinked to original sources

bioRxiv2024

Orthohantavirus Diversity in Central-East Argentina: Insights from Complete Genomic Sequencing on Phylogenetics, Geographic patterns and Transmission scenarios.

Hantavirus Pulmonary Syndrome (HPS), characterized by its high fatality rate, poses a significant public health concern in the Americas. Phylogenetic relationships of orthohantaviruses in the country were inferred from partial genomic sequences. The objectives of this work were to report new complete viral genomes of the known viral variants associated with HPS cases in Central-East region of Argentina, to assess viral diversity, phylogenetic relationships, and to elucidate the geographic patterns of distribution of each variant. To accomplish this, a detailed analysis was conducted of the geographic distribution of reported cases within the most impacted province of the region. The phylogenetic analysis defined clearly separated clades in the country according to their geographic origin. Andes virus (ANDV) segregated from the rest of the sequences, and those representative from the Central East region, Buenos Aires (BAV) and Lechiguanas virus (LECV), were grouped in the same cluster but segregated in two different branches. ImportanceIn Argentina, most of the HPS cases were associated with ANDV and closely related viruses distributed in four endemic regions. This work focused on obtaining and studying the complete genome of the orthohantaviruses present in the Central East (CE) region (BAV and LECV). Both viruses were responsible for major and minor outbreaks of person- to-person transmission in the country, and the findings may pave the way to study the impact of genetic determinants of viral transmission and to consider the reclassification of the species Orthohantavirus andesense.

genomics↗

bioRxiv2023

Andes virus genome mutations that are likely associated with animal-model attenuation and human person-to-person transmission

STRUCTURED ABSTRACTO_ST_ABSAbstractC_ST_ABSWe performed whole-genome sequencing with bait-enrichment techniques to analyze Andes virus (ANDV), a cause of human hantavirus pulmonary syndrome. We used cryopreserved lung tissues from a naturally infected long-tailed colilargo; early, intermediate, and late cell-culture passages of an ANDV isolate from that animal; and lung tissues from golden hamsters experimentally exposed to that ANDV isolate. The resulting complete genome sequences were subjected to detailed comparative genomic analysis against American orthohantaviruses. We identified four amino-acid substitutions related to cell-culture adaptation that resulted in attenuation of ANDV in the typically lethal golden hamster animal model of hantavirus pulmonary syndrome. Mutations in the ANDV nucleocapsid protein, glycoprotein, and small nonstructural protein open reading frames correlated with mutations typical for ANDV strains associated with increased pathogenesis in the small animal model. Finally, we identified three amino-acid substitutions, two in the small nonstructural protein and one in the glycoprotein, that were only present in the clade of viruses associated with person-to-person efficient transmission. Our results indicate that there are virulence-associated and transmission-associated single-nucleotide polymorphisms that could be used to predict strain-specific ANDV virulence and/or transmissibility. ImportanceSeveral orthohantaviruses cause the zoonotic disease hantavirus pulmonary syndrome (HPS) in the Americas. Among them, HPS caused by Andes virus (ANDV) is of great public-health concern because it is associated with the highest case-fatality rate (up to 50%). ANDV is also the only orthohantavirus associated with relatively robust evidence of person-to-person transmission. This work reveals nucleotide changes in the ANDV genome that are associated with virulence attenuation in an animal model and increased transmissibility in humans. These findings may pave the way to early severity predictions in future ANDV-caused HPS outbreaks.

microbiology↗

bioRxiv2019

NOX4 regulates TGFβ-induced proliferation and self-renewal in glioblastoma stem cells.

Glioblastoma (GBM) is the most aggressive and common glioma subtype with a median survival of 15 months after diagnosis. Current treatments have limited therapeutic efficacy, thus more effective approaches are needed. The glioblastoma tumoral mass is characterized by a small cellular subpopulation, the Glioblastoma stem cells (GSCs), which has been held accountant for initiation, invasion, proliferation, relapse and resistance to chemo- and radiotherapy. Targeted therapies against GSCs are crucial, and so is the understanding of the molecular mechanisms that govern the GSCs. Transforming growth factor {beta} (TGF{beta}), platelet growth factor (PDGF) signalling and Reactive Oxygen Species (ROS) production govern and regulate cancer-stem cell biology. In this work, we focus on the role of the NADPH oxidase 4 (NOX4) downstream of TGF{beta} signalling in the GSCs. NOX4 utilises NADPH to generate ROS; TGF{beta} induces NOX4 expression, thus increasing ROS production. Interestingly, NOX4 itself regulates GSC self-renewal and modulates Since TGF{beta} regulates PDGFB in GSC, we analysed how PDGFB modulates NOX4 expression and increases ROS production. Both TGF{beta} and PDGF signalling regulate GSC proliferation in a NOX4/ROS-dependent manner. The transcription factor NRF2, involved in the transcriptional regulation of antioxidant and metabolic responses, is regulated by both TGF{beta} and NOX4. This results in an antioxidant response, which positively contributes to GSC self-renewal and proliferation. In conclusion, this work functionally establishes NOX4 as a key mediator of GSC biology.

cancer biology↗