Potencial efeito neuroprotetor, imunomodulador e antiviral do ômega-3 (DHA) na infecção neuronal e microglial pelo vírus Zika

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Medicina, Programa de Pós-Graduação em Patologia Molecular, 2021.O vírus Zika (ZIKV) possui um intenso tropismo por células neurais e tem sido correlacionado com o desenvolvimento agravos neurológicos pós-infecção. Além disso, a infecção por este vírus está associada ao estabelecimento de uma neuroinflamação intensa, sendo esta majoritariamente orquestrada por células microgliais. O impacto negativo da infecção pelo ZIKV no Sistema Nervoso Central (SNC) é amplamente caracterizado na literatura. Contudo, a aplicação de moléculas capazes de proteger contra os efeitos citotóxicos causados por este vírus ainda é necessária. Neste contexto, tem sido extensamente demonstrado que o Ácido Docosahexaenoico (DHA), um ácido-graxo poli-insaturado de ômega-3, é altamente neuroprotetor e desempenha diferentes funções essenciais para a homeostase do SNC. Portanto, neste trabalho, nós investigamos o papel protetor do DHA contra a patogênese do ZIKV em células SH-SY5Y, utilizadas como neuronal-like cells, e em células microgliais humanas. Nossos dados demonstraram que o pré-tratamento com DHA foi capaz de aumentar a viabilidade e proliferação de células SH-SY5Y infectadas com ZIKV, bem como de reduzir a produção de citocinas pró-inflamatórias produzidas durante a infecção. O DHA também foi capaz de restaurar a função mitocondrial e prevenir contra o estresse oxidativo que foram induzidos pelo ZIKV. Em células microgliais, o DHA reduziu a proliferação, biogênese de corpúsculos lipídicos, produção de espécies reativas e produção de citocinas pró-inflamatórias durante a infecção do ZIKV. Além disso, o DHA modulou importantes marcadores de membrana associados à função regulatória e de apresentação de antígenos pela micróglia. Investigando acerca de alterações metabólicas durante a infecção, demonstramos que tanto o ZIKV como o DHA modulam intermediários do ciclo do ácido cítrico e o perfil metabólico global da micróglia. Ademais, o DHA foi capaz de reduzir a carga viral tanto das células microgliais, quanto das neuronais. Em conjunto, esses dados demonstram que o DHA possui um potencial neuroprotetor, imunomodulador e antiviral, sendo uma molécula promissora para intervenções terapêuticas contra a infecção do ZIKV.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) e Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).Zika virus (ZIKV) has a major tropism for neural cells and has been correlated with post-infection neurological syndromes. Furthermore, this viral infection can lead to the establishment of exacerbated neuroinflammation, which is mostly driven by microglial cells. The negative impact of ZIKV infection on the Central Nervous System (CNS) is widely characterized. However, the application of molecules capable of protecting against cytotoxic effects caused by this virus still is necessary. In this context, it has been extensively demonstrated that Docosahexaenoic Acid (DHA), a polyunsaturated omega 3 fatty acid, is highly neuroprotective and orchestrates essential functions for CNS homeostasis. Therefore, in the present work, we investigated the protective roles of DHA against ZIKV pathogenesis using SH-SY5Y, a neuronal-like cell, and human microglial cells. Our data showed that pretreatment with DHA prior to infection was able to improve viability and proliferation of SH-SY5Y cells, and to reduce cell death, pro-inflammatory cytokines and chemokines induced by ZIKV. DHA pretreatment was also able to restore mitochondrial function and prevent against oxidative stress that were induced by ZIKV infection. In microglial cells, DHA reduced proliferation, lipid droplet biogenesis, reactive species production and pro-inflammatory agents. In addition, DHA modulated important membrane markers associated with the regulatory function and presentation of peptide and lipid antigens by microglia. Investigating about metabolic shifts during ZIKV infection, we demonstrated that both ZIKV and DHA modulate citric acid cycle intermediates and the global metabolic profile of microglial cells. Furthermore, DHA was able to reduce viral load in both microglial and neuronal cells. Taken together, these data demonstrate that DHA has a neuroprotective, immunomodulatory and antiviral potential, being a promising molecule for therapeutic strategies against ZIKV infection

Hypercoagulopathy and adipose tissue exacerbated inflammation may explain higher mortality in COVID-19 patients with obesity

COVID-19, caused by SARS-CoV-2, is characterized by pneumonia, lymphopenia, exhausted lymphocytes and a cytokine storm. Several reports from around the world have identified obesity and severe obesity as one of the strongest risk factors for COVID-19 hospitalization and mechanical ventilation. Moreover, countries with greater obesity prevalence have a higher morbidity and mortality risk of developing serious outcomes from COVID-19. The understanding of how this increased susceptibility of the people with obesity to develop severe forms of the SARS-CoV-2 infection occurs is crucial for implementing appropriate public health and therapeutic strategies to avoid COVID-19 severe symptoms and complications in people living with obesity. We hypothesize here that increased ACE2 expression in adipose tissue displayed by people with obesity may increase SARS-CoV-2 infection and accessibility to this tissue. Individuals with obesity have increased white adipose tissue, which may act as a reservoir for a more extensive viral spread with increased shedding, immune activation and pro-inflammatory cytokine amplification. Here we discuss how obesity is related to a pro-inflammatory and metabolic dysregulation, increased SARS-CoV-2 host cell entry in adipose tissue and induction of hypercoagulopathy, leading people with obesity to develop severe forms of COVID-19 and also death. Taken together, it may be crucial to better explore the role of visceral adipose tissue in the inflammatory response to SARSCoV-2 infection and investigate the potential therapeutic effect of using specific target anti-inflammatories (canakinumab or anakinra for IL-1β inhibition; anti-IL-6 antibodies for IL-6 inhibition), anticoagulant or anti-diabetic drugs in COVID-19 treatment of people with obesity. Defining the immunopathological changes in COVID-19 patients with obesity can provide prominent targets for drug discovery and clinical management improvement

The use of the anticoagulant heparin and corticosteroid dexamethasone as prominent treatments for COVID-19

COVID-19 is spreading worldwide at disturbing rates, overwhelming global healthcare. Mounting death cases due to disease complications highlight the necessity of describing efficient drug therapy strategies for severe patients. COVID-19 severity associates with hypercoagulation and exacerbated inflammation, both influenced by ACE2 downregulation and cytokine storm occurrence. In this review, we discuss the applicability of the anticoagulant heparin and the anti-inflammatory corticosteroid dexamethasone for managing severe COVID-19 patients. The upregulated inflammation and blood clotting may be mitigated by administrating heparin and its derivatives. Heparin enhances the anticoagulant property of anti-thrombin (AT) and may be useful in conjunction with fibrinolytic drugs for severe COVID-19 patients. Besides, heparin can also modulate immune responses, alleviating TNF-α-mediated inflammation, impairing IL-6 production and secretion, and binding to complement proteins and leukotriene B4 (LTB4). Moreover, heparin may present anti-SARS-CoV-2 potential once it can impact viral infectivity and alter SARS-CoV-2 Spike protein architecture. Another feasible approach is the administration of the glucocorticoid dexamethasone. Although glucocorticoid's administration for viral infection managing is controversial, there is increasing evidence demonstrating that dexamethasone treatment is capable of drastically diminishing the death rate of patients presenting with Acute Respiratory Distress Syndrome (ARDS) that required invasive mechanical ventilation. Importantly, dexamethasone may be detrimental by impairing viral clearance and inducing hyperglycemia and sodium retention, hence possibly being deleterious for diabetics and hypertensive patients, two major COVID-19 risk groups. Therefore, while heparin's multitarget capacity shows to be strongly beneficial for severe COVID-19 patients, dexamethasone should be carefully administered taking into consideration underlying medical conditions and COVID-19 disease severity. Therefore, we suggest that the multitarget impact of heparin as an anti-viral, antithrombotic and anti-inflammatory drug in the early stage of the COVID-19 could significantly reduce the need for dexamethasone treatment in the initial phase of this disease. If the standard treatment of heparins fails on protecting against severe illness, dexamethasone must be applied as a potent anti-inflammatory shutting-down the uncontrolled and exacerbated inflammation

Potential neuroprotective and antiinfammatory efects provided by omega-3 (DHA) against Zika virus infection in human SH-SY5Y cells

Zika virus (ZIKV) has a strong tropism for the nervous system and has been related to post-infection neurological syndromes. Once neuronal cells are infected, the virus is capable of modulating cell metabolism, leading to neurotoxicity and cellular death. The negative efect of ZIKV in neuron cells has been characterized. However, the description of molecules capable of reversing these cytotoxic efects is still under investigation. In this context, it has been largely demonstrated that docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid, is highly neuroprotective. Here, we hypothesized that DHA’s neuroprotective proprieties could have an infuence on ZIKV-induced neurotoxicity in SHSY5Y cells. Our data showed that pre-treatment of SH-SY5Y cells with DHA increased the cell viability and proliferation in ZIKV-infected cells. Moreover, DHA triggered an anti-infammatory response in those infected cells. Besides, DHA was capable of restoring mitochondria function and number in ZIKVinfected SH-SY5Y cells. In addition, cells pre-treated with DHA prior to ZIKV infection presented a lower viral load at diferent times of infection. Taking together, these results demonstrated that DHA has a potential anti-infammatory and neuroprotective efect against ZIKV infection in these neuron-like cells and could be a useful tool in the treatment against this virus

Gut microbiota modulation induced by Zika virus infection in immunocompetent mice

Abstract Gut microbiota composition can modulate neuroendocrine function, inflammation, and cellular and immunological responses against different pathogens, including viruses. Zika virus (ZIKV) can infect adult immunocompetent individuals and trigger brain damage and antiviral responses. However, it is not known whether ZIKV infection could impact the gut microbiome from adult immunocompetent mice. Here, we investigated modifications induced by ZIKV infection in the gut microbiome of immunocompetent C57BL/6J mice. Adult C57BL/6J mice were infected with ZIKV and the gut microbiota composition was analyzed by next-generation sequencing of the V4 hypervariable region present in the bacterial 16S rDNA gene. Our data showed that ZIKV infection triggered a significant decrease in the bacteria belonging to Actinobacteria and Firmicutes phyla, and increased Deferribacteres and Spirochaetes phyla components compared to uninfected mice. Interestingly, ZIKV infection triggered a significant increase in the abundance of bacteria from the Spirochaetaceae family in the gut microbiota. Lastly, we demonstrated that modulation of microbiota induced by ZIKV infection may lead to intestinal epithelium damage and intense leukocyte recruitment to the intestinal mucosa. Taken together, our data demonstrate that ZIKV infection can impact the gut microbiota composition and colon tissue homeostasis in adult immunocompetent mice