Exposures to Heat-Inactivated SARS-CoV-2 Causes Reactive Oxygen Species Generation And Inflammatory Response in RAW 264.7 Cells

Introduction and Objectives Novel SARS-CoV-2 virus has been implicated in prompting a bold immune response that leads to severe Coronavirus disease 2019 (COVID-19). Recent studies have shown that SARSCoV-2-infected monocytes and macrophages are stimulated to produce an overabundance of pro-inflammatory cytokines and chemokines to generate a cytokine storm. Cytokines in excess can contribute to local tissue inflammation and the pathogenesis of COVID-19. However, the mechanism by which SARS-CoV-2 signal macrophage-derived inflammatory response remains unclear. In the present study, we used RAW 264.7 cells, a wellcharacterized macrophage model, to study the in vitro effects of SARS-CoV-2 on reactive oxygen species (ROS) production and its potential role in the signal transduction of cytokine production. Methods The effect of SARS-CoV-2 on ROS and cytokine generation in macrophages was assessed by treating RAW 264.7 cells with SARS-CoV-2 heat inactivated virus (0-20 million viral particles) or recombinant proteins for 24 hours. 2',7'-Dichlorodihydrofluorescein (2',7'-DCF) fluorescence analysis was utilized to quantify ROS generation within the RAW 264.7 macrophage cell line. Cell culture medium was sampled to quantify the levels of tumor necrosis factor (TNF) using enzyme-linked immunosorbent assay (ELISA). To assess the effects of SARS-CoV-2 on mitochondrial function, cells were treated with SARS-CoV-2 heat inactivated virus (0-20 million viral particles) for 24 hrs. Mitochondria-derived superoxide was measured using the MitoSOX™ red mitochondrial superoxide indicator. Results Treatment of RAW 264.7 cells with inactivated SARS-CoV-2 viral particles or recombinant proteins stimulated ROS production. Mitochondria-derived superoxide and hydrogen peroxide production were increased in response to inactivated SARS-CoV-2 viral particles and recombinant protein exposure. The increased ROS generation is linked to macrophage activation induced by SARS-CoV-2 exposures. Along with the ROS generation, increased TNF production was observed. Conclusions The results of this study suggest that both SARS-CoV-2 viral proteins and heat-inactivated viral particle exposures cause significant generation of ROS and cytokines by RAW 264.7 cells. ROS generation and the subsequent cytokine release apparently play a significant role in the pathogenesis associated with the SARS-CoV-2 viral infection. The imbalanced cellular defense system against oxidative stress commonly associated with aging could explain the increased occurrence of more severe SARS-CoV-2 illness in seniors and in patients with underlying health conditions. Based on the results from this study, we propose that antioxidants such as N-acetyl-L-cysteine, resveratrol, or Vitamin E in combination with antiinflammatory drug could be used to control excess ROS and cytokines in patients with severe COVID-19.

Performance Assessment of Random Forest Induction Methods

In this paper, we propose a performance assessment of a forest induction method called IDTNIM-RF which uses the IDT_NIM "Induction of Decision Tree New Information Measure" for the trees induction. The specific techniques applied to forests such as bagging and random feature selection are used for generating multiple IDT_NIM trees. We compare the IDTNIM-RF method with a RF random forest that uses CART as a basic rule. The success rate criterion of the single CART and IDT_NIM trees used respectively to generate URF and IDTNIM-RF forest sets is used as a performance assessment basis. To achieve this evaluation, data sets are carried from the UCI Repository and some learning bases we have already developed such MONITDIAB and COVID_EHU.

COVID-19 Infection Prediction and Classification

Symptoms associated with COVID-19 are very similar to and difficult to distinguish from those of seasonal flu, bronchitis, or pneumonia. The use of tests, expensive and unavailable in most countries, especially developing ones, may be unnecessary in the case of a suspected COVID. This work is carried out in order to decide if a patient is a priori infected and must be tested. Otherwise, the patient will not be screened using a confidence threshold. The data is collected at the emergency department of the EHU of Oran in Algeria. The COVID-19infection classification and prediction are performed by decision trees. © 2021, Springer Nature Switzerland AG.