Biology subjects

Chaves, I. d. M.

Publications and source records attributed to Chaves, I. d. M..

4 recordsLinked to original sources

bioRxiv2025

Annexin A1 as a key modulator of lung inflammation during coronavirus infections

Exacerbated inflammation is a major contributor to tissue damage and mortality in infectious diseases, including SARS-CoV-2. The resolution phase of inflammation is critical for restoring tissue homeostasis following an injury. Annexin A1 (AnxA1) is a ubiquitous protein that plays a fundamental role in the resolution of inflammation, including in preclinical models of infectious disease. Here, we investigated the role of AnxA1 in coronavirus infection and its potential as a host-targeted therapeutic strategy against SARS-CoV-2. Wild-type (WT) and AnxA1 knockout (AnxA1KO) mice were intranasally infected with the murine betacoronavirus MHV-3 to study the endogenous role of AnxA1. Immunohistochemistry and Western blot analyses in the lungs of MHV-3-infected mice revealed increased AnxA1 expression and its cleavage, which was associated with neutrophilic infiltration (Ly6G+ cells) mainly in peribronchiolar and perivascular regions. AnxA1-deficient mice exhibited higher neutrophilic infiltration and lung damage, alongside increased CXCL1 production in the lungs, when compared to WT-infected mice. In a murine model of SARS-CoV-2 infection in K18-hACE2 mice, we found increased AnxA1 cleavage associated with lung inflammation. Treatment of SARS-CoV-2-infected K18-hACE2 mice with the AnxA1-mimetic peptide, Ac2-26, reduced lung damage and lethality, without altering the host ability to deal with viral replication. Notably, Ac2-26-treated mice exhibited similar levels of protection to that afforded by the nucleotide analogue Remdesivir, following SARS-CoV-2 infection. Our findings highlight the protective role of the endogenous AnxA1 in mitigating coronavirus-induced lung inflammation and underscore the therapeutic potential of AnxA1 mimetic Ac2-26 as a host-targeted therapy against SARS-CoV-2.

immunology↗

bioRxiv2025

Broad-Spectrum Antiviral Efficacy of 7-Deaza-7-Fluoro-2'-C-Methyladenosine Against Multiple Coronaviruses In Vitro and In Vivo

The Coronaviridae family has been implicated in several major epidemics over the past two decades, including those caused by SARS-CoV, MERS-CoV, and, most recently, SARS-CoV-2. The COVID-19 pandemic, driven by SARS-CoV-2, has led to over seven million deaths worldwide and has been associated with prolonged symptoms, chronic sequelae, and substantial socioeconomic disruptions. The limited availability of effective antiviral treatments, coupled with the ability of coronaviruses to mutate and evade immune defenses, underscores the urgent need for innovative antiviral agents. This study explores the efficacy of the nucleoside analogue DFMA as a potential antiviral agent against multiple Coronaviridae family members, including SARS-CoV-2 and two strains of murine hepatitis viruses (MHV-3 and MHV-A59). In vitro analyses demonstrated that DFMA effectively reduced the viral load in the supernatant of infected cells and enhanced cell viability for both MHV-3 and MHV-A59. Against SARS-CoV-2, DFMA showed a significant reduction in viral load, with a calculated Selectivity Index (SI) of 6.2. In vivo investigations further confirmed the antiviral potential of DFMA. In three distinct murine models--a severe COVID-19 model using MHV-3, a mild COVID-19 model employing MHV-A59, and a transgenic K18-hACE2 mouse model infected with SARS-CoV-2--DFMA administration significantly reduced viral loads in the lungs of infected mice. Additionally, DFMA mitigated inflammatory responses in all models by lowering levels of key inflammatory mediators, such as CXCL1, CCL2, and IL-6. These findings suggest that DFMA possesses broad-spectrum antiviral activity against coronaviruses and may serve as a promising therapeutic candidate for current and future coronavirus outbreaks. Further research is warranted to elucidate its mechanism of action and evaluate its efficacy in clinical settings. ImportanceCoronaviruses have caused significant outbreaks over the past two decades. Since 2020, COVID-19 has resulted in millions of deaths and lasting global impacts. The limited availability of effective antivirals and the viruss ability to mutate and evade vaccines and monoclonal antibody therapy emphasize the urgent need for new treatments. This study investigates DFMA, a promising antiviral candidate, targeting SARS-CoV-2 and two related coronaviruses.Our promising results demonstrated significant antiviral activity of DFMA, not only against SARS-CoV-2 but also against other similar coronaviruses, indicating potential future use against COVID-19 and other possible coronavirus-related diseases.

microbiology↗

bioRxiv2024

Neuropsychiatric sequelae in an experimental model of post-COVID syndrome in mice

The global impact of the COVID-19 pandemic has been unprecedented, and presently, the world is facing a new challenge known as Post-COVID syndrome (PCS). Current estimates suggest that more than 65 million people are grappling with PCS, encompassing several manifestations, including pulmonary, musculoskeletal, metabolic, and neuropsychiatric sequelae (cognitive and behavioral). The mechanisms underlying PCS remain unclear. The present study aimed to: (i) comprehensively characterize the acute effects of pulmonary inoculation of the betacoronavirus MHV-A59 in immunocompetent mice at clinical, cellular, and molecular levels; (ii) examine potential acute and long-term pulmonary, musculoskeletal, and neuropsychiatric sequelae induced by the betacoronavirus MHV-A59; and to (iii) assess sex-specific differences. Male and female C57Bl/6 mice were initially inoculated with varying viral titers (3x103 to 3x105 PFU/30 L) of the betacoronavirus MHV-A59 via the intranasal route to define the highest inoculum capable of inducing disease without causing mortality. Further experiments were conducted with the 3x104 PFU inoculum. Mice exhibited an altered neutrophil/lymphocyte ratio in the blood in the 2nd and 5th day post-infection (dpi). Marked lung lesions were characterized by hyperplasia of the alveolar walls, infiltration of polymorphonuclear leukocytes (PMN) and mononuclear leukocytes, hemorrhage, increased concentrations of CCL2, CCL3, CCL5, and CXCL1 chemokines, as well as high viral titers until the 5th dpi. While these lung inflammatory signs resolved, other manifestations were observed up to the 60 dpi, including mild brain lesions with gliosis and hyperemic blood vessels, neuromuscular dysfunctions, anhedonic-like behavior, deficits in spatial working memory, and short-term aversive memory. These musculoskeletal and neuropsychiatric complications were exclusive to female mice and were prevented after ovariectomy. In summary, our study describes for the first time a novel sex-dependent model of PCS focused on neuropsychiatric and musculoskeletal disorders. This model provides a unique platform for future investigations regarding the effects of acute therapeutic interventions on the long-term sequelae unleashed by betacoronavirus infection.

neuroscience↗

bioRxiv2021

A suitable murine model for studying respiratory coronavirus infection and therapeutic countermeasures in BSL-2 laboratories

Several animal models are being used to explore important features of COVID-19, nevertheless none of them recapitulates all aspects of the disease in humans. The continuous refinement and development of other options of in vivo models are opportune, especially ones that are carried out at BSL-2 (Biosafety Level 2) laboratories. In this study, we investigated the suitability of the intranasal infection with the murine betacoronavirus MHV-3 to recapitulate multiple aspects of the pathogenesis of COVID-19 in C57BL/6J mice. We demonstrate that MHV-3 replicated in lungs 1 day after inoculation and triggered respiratory inflammation and dysfunction. This MHV-model of infection was further applied to highlight the critical role of TNF in cytokine-mediated coronavirus pathogenesis. Blocking TNF signaling by pharmacological and genetic strategies greatly increased the survival time and reduces lung injury of MHV-3-infected mice. In vitro studies showed that TNF blockage decreased SARS-CoV-2 replication in human epithelial lung cells and resulted in the lower release of IL-6 and IL-8 cytokines beyond TNF itself. Taken together, our results demonstrate that this model of MHV infection in mice is a useful BSL-2 screening platform for evaluating pathogenesis for human coronaviruses infections, such as COVID-19.

microbiology↗