A proteomic perspective and involvement of cytokines in SARS-CoV-2 infection.

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 now carried out detailed proteomic analysis of the nasopharyngeal/oropharyngeal swab samples collected from normal individuals and those tested positive for SARS-CoV-2, in India, during the early days of the pandemic in 2020, 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.

Down regulation of defensin genes during SARS-CoV-2 infection.

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. In this study, we have investigated the expression of defensin genes in the buccal cavity from patients with COVID-19 infection along with negative control samples. Nasopharyngeal/oropharyngeal swab samples collected for screening SARS-CoV-2 infection in early 2020 from Hyderabad, India, were analyzed for the expression of major defensin genes by the quantitative real-time reverse transcription polymerase chain reaction, qRT-PCR. Forty SARS-CoV-2 infected positive and 40 negative swab samples were selected for this study. Based on the qRT-PCR analysis involving gene specific primers for defensin genes, 9 defensin genes were found to be expressed in the nasopharyngeal/oropharyngeal cavity. Four defensin genes were found to be significantly down regulated in SARS-CoV-2 infected patients in comparison with the control samples based on differential expression analysis. The significantly down regulated genes were defensin beta 4A/B, 106B, 107B, and 103A. Down regulation of human beta defensin 2, 3, 6 and 7 suggests that antiviral innate immune response provided by defensins may be compromised in SARS-CoV-2 infection resulting in progression of the disease. Correction of the down regulation process through appropriate defensin peptide-based therapy could be an attractive method of treatment. Keywords: host defense; defensins; COVID-19; gene regulation; SARS-CoV-2.

Gramicidin S and melittin: potential anti-viral therapeutic peptides to treat SARS-CoV-2 infection.

The COVID19 pandemic has led to 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 the well-studied antibacterial peptides gramicidin S and melittin obtained from Bacillus brevis and bee venom respectively. The EC50 values for gramicidin S and melittin were 1.571 µg and 0.656 µg respectively based on in vitro antiviral assay. Significant decrease in the viral load as compared to the untreated group with no/very less cytotoxicity was observed. Both the peptides treated to the SARS-CoV-2 infected Vero cells showed viral clearance from 12 h onwards with a maximal viral clearance after 24 h post infection. Proteomics analysis indicated that more than 250 proteins were 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 h 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.

Understanding the complexity of epimorphic regeneration in zebrafish caudal fin tissue: A transcriptomic and proteomic approach.

The complex epimorphic regeneration of zebrafish caudal fin tissue is hasty and absolute. This study was executed to understand the role of various genes/proteins involved in the regeneration of zebrafish caudal fin tissue through differential transcriptomics and proteomics analysis. Based on our study 1408 genes and 661 proteins were found differentially regulated in the regenerating caudal fin tissue for having at least 1-log fold change. Interleukin, Solute carrier, Protein arginine methyltransferase, Homeobox, Neurotransmitter and several novel genes were found to be associated with regeneration for its differential regulation during the mechanism. Based on the network and pathway analysis the differentially regulated genes and proteins were found allied with activation of cell proliferation, cell viability, cell survival & cell movement and inactivation of organismal death, morbidity, necrosis, death of embryo & cell death. This study has mapped a detailed insight of the genes/proteins expression associated with the epimorphic regeneration more profoundly.

Transcriptomic and proteomic analysis of Hemidactylus frenatus during initial stages of tail regeneration.

Epimorphic regeneration of appendages is a complex and complete phenomenon found in selected animals. Hemidactylus frenatus, house gecko has the remarkable ability to regenerate the tail tissue upon autotomy involving epimorphic regeneration mechanism. This study has identified and evaluated the molecular changes at gene and protein level during the initial stages, i.e., during the wound healing and repair mechanism initiation stage of tail regeneration. Based on next generation transcriptomics and De novo analysis the transcriptome library of the gecko tail tissue was generated. A total of 254 genes and 128 proteins were found to be associated with the regeneration of gecko tail tissue upon amputation at 1, 2 and 5-day post amputation (dpa) against control, 0-dpa through differential transcriptomic and proteomic analysis. To authenticate the expression analysis, 50 genes were further validated involving RTPCR. 327 genes/proteins identified and mapped from the study showed association for Protein kinase A signaling, Telomerase BAG2 signaling, paxillin signaling, VEGF signaling network pathways based on network pathway analysis. This study empanelled list of transcriptome, proteome and the list of genes/proteins associated with the tail regeneration.

Functional role of annexins in zebrafish caudal fin regeneration - A gene knockdown approach in regenerating tissue.

Regeneration is an adaptive phenomenon with wide biological implications spread heterogeneously in almost all the organism including human beings. The ability of regeneration varies from species to species for its complexity. Epimorphic regeneration of zebrafish caudal fin tissue is the most widely studied regeneration mechanism for its discrete and rapid regenerative capability. Several genes and proteins were found to be associated with regenerative mechanisms of zebrafish caudal fin tissue. In this study we have evaluated the functional role of Annexin 2a and 2b genes during zebrafish caudal fin tissue regeneration using inventive electroporation techniques for targeting the gene involving CRISPR-Cas9 technology. The electroporation of the CRISPR was performed on the adult zebrafish caudal fin tissue post amputation. We report retarded growth during the regeneration of caudal fin tissue when Annexin 2a and 2b genes were knocked down, which was validated through gene expression & sequencing analysis and further supported by high-throughput quantitative proteomic analysis of the fin tissue. Annexin family genes such as ANXA13, ANXA1a, ANXA5b were also found to be repressed with their expression. Knocking down of ANXA2a and 2b in regenerating caudal fin tissue compromises regenerating capacity as these genes are involved in cell to cell communication and extracellular matrix growth. This study proves that ANXA2a and 2b plays a significant role in epimorphic regeneration of zebrafish caudal fin tissue.