Biology subjects

Santos, F. R. d. S.

Publications and source records attributed to Santos, F. R. d. S..

4 recordsLinked to original sources

bioRxiv2025

Cyclodextrin-Based Delivery of the Annexin A1 Mimetic Peptide Ac2-26 Enhances Anti-Inflammatory Effects and PreventsDengue-Induced Lethality in Combination with AntiviralTherapy

Severe dengue is characterized by systemic inflammation, cytokine storm, vascular leakage, and hemorrhagic manifestations, largely driven by the host immune response to dengue virus (DENV) infection. Despite its burden, no licensed antivirals or host-directed therapies are currently available. Our group has previously identified Annexin A1 (AnxA1) as an endogenous regulator of inflammation in dengue. Treatment with the AnxA1 peptidomimetic, Ac2-26, improved clinical outcomes in murine models of severe dengue by promoting resolution of inflammation without affecting viral control. To explore new delivery strategies, we developed a novel formulation of Ac2-26 complexed with hydroxypropyl-{beta}-cyclodextrin (CDX-Ac2-26). In DENV-2-infected A129 mice, both intraperitoneal and oral CDX-Ac2-26 improved clinical scores and reversed thrombocytopenia. Notably, CDX-Ac2-26 reduced mast cell degranulation, MCPT-1 plasma levels, and CCL2 expression in spleen, with no effect on viral titers, indicating a host-targeted mechanism and overcoming the anti-inflammatory effects of the free peptide. Intraperitoneal administration achieved the same efficacy as oral dosing with only one-third of the dose. Importantly, the combination of CDX-Ac2-26 with the antiviral nucleotide analog sofosbuvir fully prevented disease and mortality in infected mice, highlighting a combinatorial effect between host-directed and antiviral therapies. These findings underscore the therapeutic potential of anti-inflammatory/pro-resolving strategies in severe dengue and support the development of CDX-Ac2-26 as a novel adjunctive treatment. Combining anti-inflammatory and antiviral approaches may enhance efficacy and reduce treatment-associated toxicity, offering a promising path for clinical translation. What is already known on this topic?O_LIPlasma levels of Annexin A1 are inversely correlated with the severity of clinical outcomes in dengue virus infection. C_LIO_LIThe Annexin A1 peptidomimetic Ac2-26 exhibits anti-inflammatory and pro-resolving effects against severe dengue in a murine model. C_LI What does this study add?O_LIThe Ac2-26-cyclodextrin complex enhances the anti-inflammatory effects of the peptide against dengue virus infection, allowing for lower dosing and oral administration. C_LIO_LIThe administration of the CDX-Ac2-26 with a nucleoside analog antiviral exhibits a combinatorial effectt, providing complete protection against the lethal outcome of severe dengue. C_LI What is the clinical significance?O_LICurrent dengue treatment relies on symptomatic management, as no directed anti-inflammatory agents or antivirals are currently available. We have identified a novel host-targeted strategy to resolve the disease. C_LIO_LIOur findings strongly support CDX-Ac2-26 as a promising adjunctive treatment strategy in combination with antiviral therapy for severe dengue, highlighting the potential of combinatorial approaches. C_LI

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

PI3Kγ pathway contributes to neuroinflammation and neuronal death induced by Zika virus infection

Zika virus (ZIKV) is an emerging arbovirus belonging to the Flaviviridae family and Orthoflavivirus genus, with a pronounced tropism for the central nervous system (CNS), where it induces neuroinflammation and neuronal death. ZIKV is known to exploit host cellular mechanisms, including the activation of survival pathways such as the PI3K/AKT signaling cascade, to evade apoptosis and enhance its replication. The phosphatidylinositol 3-kinase {gamma} (PI3K{gamma}) pathway regulates critical cellular processes, including differentiation, recruitment, and survival, and is abundantly expressed in both brain tissue and leukocytes. This study aimed to investigate the role of the PI3K{gamma} pathway during ZIKV infection. Primary neuronal cultures from PI3K{gamma}-deficient mice (PI3K{gamma}kd/kd) and human neuroblastoma SH-SY5Y cells treated with the PI3K{gamma} inhibitor AS605240 were infected with ZIKV to assess the impact of PI3K{gamma} signaling on viral replication and neuronal survival. Additionally, interferon /{beta} receptor knockout (A129) mice were treated with AS605240 either before or after ZIKV infection to evaluate the pathways role in neuroinflammation. In vitro, both genetic ablation and pharmacological inhibition of PI3K{gamma} suppressed ZIKV replication and prevented neuronal death. In vivo, mice treated with the PI3K{gamma} inhibitor exhibited enhanced protection against ZIKV infection, characterized by reduced viral load, and diminished brain and optic nerve damage. This neuroprotective effect correlated with altered astrocyte and microglia activation, marked by reduced TNF production in microglia. Furthermore, inhibition of PI3K{gamma} curtailed the recruitment and activation of CD8+ T cells and decreased the production of pro-inflammatory mediators, including IFN-{gamma} and IL-17, in the brains of ZIKV-infected mice. These findings suggest that PI3K{gamma} activation facilitates ZIKV infection and exacerbates neuroinflammation. Pharmacological inhibition of the PI3K{gamma} pathway may offer therapeutic benefits by limiting viral replication and alleviating neuroinflammatory responses during ZIKV infection.

immunology↗

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↗