RESUMEN
Infection with the SARS-CoV-2 virus results in manifestation of several clinical observations from asymptomatic to multi-organ failure. Biochemically, the serious effects are due to what is described as cytokine storm. The initial infection region for COVID-19 is the nasopharyngeal/oropharyngeal region which is the site where samples are taken to examine the presence of virus. We have earlier shown that several defensin genes are down regulated in cells from this region in patients who tested positive in the RTPCR test. We have now carried out detailed proteomic analysis of the nasopharyngeal/oropharyngeal swab samples collected from normal individuals and those tested positive for SARS-CoV-2 by RTPCR, involving high throughput quantitative proteomics analysis. Several proteins like annexins, cytokines and histones were found differentially regulated in the host human cells following SARS-CoV-2 infection. Genes for these proteins were also observed to be differentially regulated when their expression was analyzed. Majority of the cytokine proteins were found to be up regulated in the infected individuals. Cell to Cell signaling interaction, Immune cell trafficking and inflammatory response pathways were found associated with the differentially regulated proteins based on network pathway analysis.
RESUMEN
The COVID19 pandemic has resulted in multipronged approaches for treatment of the disease. Since de novo discovery of drugs is time consuming, repurposing of molecules is now considered as one of the alternative strategies to treat COVID19. Antibacterial peptides are being recognized as attractive candidates for repurposing to treat viral infections. In this study, we describe the anti-SARS-CoV-2 activity of gramicidin S and melittin peptides obtained from Bacillus brevis and bee venom respectively. Our in vitro antiviral assay results showed significant decrease in the viral load compared to the untreated group with no/very less cytotoxicity. The EC50 values for gramicidin S and melittin are calculated as 1.571g and 0.656g respectively. Both the peptides treated to the SARS-CoV-2 infected Vero cells showed viral clearance from 12 hours onwards with a maximal clearance after 24 hours post infection. Based on proteome analysis it was found that more than 250 proteins were found to be differentially regulated in the gramicidin S and melittin treated SARS-CoV-2 infected Vero cells against control SARS-CoV-2 infected Vero cells after 24 and 48 hours post infection. The identified proteins were found to be associated in the metabolic and mRNA processing of the Vero cells post-treatment and infection. Both these peptides could be attractive candidates for repurposing to treat SARS-CoV-2 infection.
RESUMEN
Defensins, crucial components of the innate immune system, play a vital role against infection as part of frontline immunity. Association of SARS-CoV-2 infection with defensins has not been investigated till date. In this study, we have investigated the expression of defensin genes in the buccal cavity during COVID-19 infection. Nasopharyngeal/Oropharyngeal swab samples collected for screening SARS-CoV-2 infection were analyzed for the expression of major defensin genes by the quantitative real-time reverse transcription polymerase chain reaction, qRT-PCR. 40 SARS-CoV-2 infected positive and 40 negative swab samples were selected for the study. Based on the RT-PCR analysis involving gene specific primer for defensin genes, 10 defensin genes were found to be expressed in the Nasopharyngeal/Oropharyngeal cavity. Six defensin genes were further found to be significantly downregulated in SARS-CoV-2 infected patients as against the control, negative samples based on differential expression analysis. The genes significantly downregulated were defensin beta 4A, 4B, 106B, 107B, 103A and defensin alpha 1B. Downregulation of several defensin genes suggests that innate immunity provided by defensins is or may be compromised in SARS-CoV-2 infection resulting in progression of the disease caused by the virus. Upregulation of defensin gene expression and use of defensin peptides could be attractive therapeutic interventions.
