Downregulation of Defensin genes in 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 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.