ARTICLE | doi:10.20944/preprints202206.0057.v1
Online: 6 June 2022 (03:56:53 CEST)
Small RNAs (sRNA) and microRNAs (miRNAs) are small endogenous noncoding single-stranded RNAs that regulate gene expression in eukaryotes. Experiments in mice and humans have revealed that a typical small RNA can affect the expression of a wide range of genes, implying that small RNAs function as global regulators. Here, we used small RNA deep sequencing to investigate at how jararhagin, a metalloproteinase toxin produced from the venom of Bothrops jararaca, affected mmu-miRs expression in mice 2 h and 24 h after injection. The findings revealed that seven mmu-miRs were substantially differentially expressed (p-value (p (Corr) cut-off 0.05, FC 2) at 2h after jararhagin exposure, and that the majority of them were upregulated when compared to PBS. In contrast to these findings, a comparison of Jar 24h vs PBS 24hrs demonstrated that the majority of identified mmu-miRs were downregulated. Furthermore, the studies demonstrated that mmu-miR can target the expression of several genes involved in the MAPK signaling pathway. The steady antithetical regulation of mmu-miRs may correlates with the expression of genes that trigger apoptosis via MAPK in the early stages, and this effect intensifies with time. The findings expand our understanding of the effects of jararhagin on local tissue lesions at the molecular level.
ARTICLE | doi:10.20944/preprints202208.0496.v1
Subject: Biology, Other Keywords: SARS-CoV-2; COVID-19; T-lymphocytes; antiviral response; cytotoxic factors
Online: 29 August 2022 (14:30:57 CEST)
COVID-19, the infectious disease caused by SARS-CoV-2, has spread on a pandemic scale. The virus infection can evolve asymptomatically or generate severe symptoms, influenced by the presence of comorbidities. Lymphopenia in patients affected with COVID-19 according to the severity of symptoms is frequent. However, the profile of CD4+ and CD8+ T-cells regarding cytotoxicity and antiviral factor expression has not yet been completely elucidated in acute SARS-CoV-2 infections. The purpose of this study is to evaluate the phenotypic and functional profile of T-lymphocytes in patients with moderate and severe/critical COVID-19. During this pandemic period, we analyzed a cohort of 62 confirmed patients with SARS-CoV-2 (22 moderate cases and 40 severe/critical cases). Albeit lymphopenia, we observed an increase in the expression of CD28, co-stimulator molecule, and activation markers (CD38 and HLA-DR) in T-lymphocytes as well as an increase in the frequency of CD4+ T-cells, CD8+ T-cells, and NK cells that express the immunological checkpoint protein, PD-1, in patients with severe/critical condition compared to healthy controls. Regarding the cytotoxic profile of peripheral blood mononuclear cells, an increase in the response of CD4+ T-cells already at baseline level was observed, scarcely changed upon PMA and Ionomycin stimulation. Meanwhile, CD8+ T-lymphocytes decreased cytotoxic response, evidencing a profile of exhaustion in patients with severe COVID-19. As observed in the t-SNE technique CD4+ T-cytotoxic and CD8+ T with low granzyme production evidencing their dysfunctionality in severe/critical conditions. In addition, purified CD8+ T-lymphocytes from patients with severe COVID-19 showed an increased constitutive expression of differentially expressed genes associated with the caspase pathway, inflammasome, and antiviral factors, and curiously, reduced expression of TNF-α. The cytotoxic profile, by CD4+ T-cells, may compensate for the dysfunction/exhaustion of TCD8+ in acute SARS-CoV-2 infection. These findings may provide an understanding of the interplay of cytotoxicity between CD4+ T-cells and CD8+ T-cells in the severity of acute COVID-19 infection.