Association of polymorphisms in serotonin and nitric oxide genes with clinical outcome of dengue in Brazilian northeast population

Immune system gene polymorphisms associated with severe dengue in Latin America: a systematic review

One of the main challenges in the clinical management of dengue is the early identification of cases that could progress to severe forms of the disease. A biomarker that may enable this identification is the presence of genetic polymorphisms in genes associated with immune responses. The objective of this study was to perform a systematic review of the Latin American literature on these genes. An electronic literature search was carried out in PubMed, Scopus, Lilacs, and the Virtual Health Library, and reference lists of systematic reviews in the area. Case-control studies conducted in Latin American countries examining at least one form of genetic polymorphism related to immune responses against severe dengue were included. In total, 424 articles were identified and 26 were included in this systematic review. Of the 26 selected articles, 16 reported polymorphisms associated with the risk of developing severe dengue (Risk); Similarly, 16 articles reported polymorphisms associated with a decreased risk of severe dengue (Protective). The final analysis revealed that multiple polymorphisms in immune system genes were early markers of the progression of dengue in Latin Americans and found that polymorphisms of the TNF-alpha gene may have a critical role in dengue pathogenesis.

Beauty and the beast: host microRNA-155 versus SARS-CoV-2

Severe acute respiratory coronavirus 2 (SARS-CoV-2) infection in the young and healthy usually results in an asymptomatic or mild viral syndrome, possibly through an erythropoietin (EPO)-dependent, protective evolutionary landscape. In the old and in the presence of co-morbidities, however, a potentially lethal coronavirus disease 2019 (COVID-19) cytokine storm, through unrestrained renin-angiotensin aldosterone system (RAAS) hyperactivity, has been described. Multifunctional microRNA-155 (miR-155) elevation in malaria, dengue virus (DENV), the thalassemias, and SARS-CoV-1/2, plays critical antiviral and cardiovascular roles through its targeted translational repression of over 140 genes. In the present review, we propose a plausible miR-155-dependent mechanism whereby the translational repression of AGRT1, Arginase-2 and Ets-1, reshapes RAAS towards Angiotensin II (Ang II) type 2 (AT2R)-mediated balanced, tolerable, and SARS-CoV-2-protective cardiovascular phenotypes. In addition, it enhances EPO secretion and endothelial nitric oxide synthase activation and substrate availability, and negates proinflammatory Ang II effects. Disrupted miR-155 repression of AT1R + 1166C-allele, significantly associated with adverse cardiovascular and COVID-19 outcomes, manifests its decisive role in RAAS modulation. BACH1 and SOCS1 repression creates an anti-inflammatory and cytoprotective milieu, robustly inducing antiviral interferons. MiR-155 dysregulation in the elderly, and in comorbidities, allows unimpeded RAAS hyperactivity to progress towards a particularly aggressive COVID-19 course. Elevated miR-155 in thalassemia plausibly engenders a favorable cardiovascular profile and protection against malaria, DENV, and SARS-CoV-2. MiR-155 modulating pharmaceutical approaches could offer novel therapeutic options in COVID-19.

Association of eNOS gene 4a/4b VNTR and T786C polymorphism with Crimean-Congo hemorrhagic fever

The most common viral hemorrhagic fever is Crimean-Congo hemorrhagic fever (CCHF). Endothelial nitric oxide synthase (eNOS) gene polymorphisms have been linked to both hemorrhagic fevers and viral diseases. The study's goal is to evaluate if the eNOS gene 4a/4b and T786C polymorphisms are related to CCHF. The study included 54 CCHF RNA-positive patients and 60 control subjects. The Bosphore CCHF virus Quantification Kit v1 was used to obtain CCHF RNA, and the Magnesia 16 isolation device was used to isolate DNA (Anatolia Gene works, Turkey). Polymerase chain reaction and restriction fragment length polymorphism were used to genotype the samples. The frequency of the eNOS 4a/4a, 4a/4b, and 4 b/4b genotypes in patients and the control was 6.6% versus 1.7%, 37.0% versus 43.3%, and 57.4% versus 55%, respectively. 4a: 24.07% of patients and 23.33% of controls; and 4 b: 75.92% of patients and 76.66% of controls. The frequency of the eNOS-786 T/C, T/T, T/C, and C/C genotypes in patients and the control group was 35.2% versus 68.3%; 51.9% versus 26.73%; and 13.0% versus 5.0%, respectively. The allele and genotype frequencies of the eNOS T786C variant differ statistically between patients and the control (p < 0.05). The eNOS T786C variant could be a genetic determinant for susceptibility to CCHF. To our knowledge, this is the first study to figure out the association between eNOS gene T786C polymorphisms and CCHF disease.