Immunological mechanisms of the nucleocapsid protein in COVID-19

Sci Rep. 2024 Feb 14;14(1):3711. doi: 10.1038/s41598-024-53906-3.

Abstract

The emergence of corona virus disease 2019 (COVID-19), resulting from Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has left an indelible mark on a global scale, causing countless infections and fatalities. This investigation delves into the role of the SARS-CoV-2 nucleocapsid (N) protein within the HEK293 cells, shedding light on its influence over apoptosis, interferon signaling, and cytokines production. The N gene was amplified, inserted into the pAdTrack-CMV vector, and then transfected to the HEK293 cells. Changes in the expression of IRF3, IRF7, IFN-β, BAK, BAX, and BCL-2 genes were evaluated. The levels of proinflammatory cytokines of IL-6, IL-12, IL-1β, and TNF-α were also determined. The N protein exhibited an anti-apoptotic effect by modulating critical genes associated with apoptosis, including BAK, BAX, and BCL-2. This effect potentially prolonged the survival of infected cells. The N protein also played a role in immune evasion by suppressing the interferon pathway, evidenced by the downregulation of essential interferon regulatory factors of IRF3 and IRF7, and IFN-β expression. The N protein expression led to a substantial increase in the production of proinflammatory cytokines of IL-6, IL-12, IL-1β, and TNF-α. The N protein emerged as a versatile factor and was exerted over apoptosis, interferon signaling, and cytokine production. These findings carry potential implications for the development of targeted therapies to combat COVID-19 and mitigate its global health impact.

Keywords: Apoptotic; Coronavirus; Cytokine storm; Nucleocapsid protein; SARS.

MeSH terms

  • COVID-19* / genetics
  • Cytokines
  • HEK293 Cells
  • Humans
  • Interferons
  • Interleukin-12
  • Interleukin-6
  • Nucleocapsid Proteins / genetics
  • Nucleocapsid Proteins / metabolism
  • SARS-CoV-2 / metabolism
  • Tumor Necrosis Factor-alpha
  • bcl-2-Associated X Protein / genetics

Substances

  • Nucleocapsid Proteins
  • Tumor Necrosis Factor-alpha
  • Interleukin-6
  • bcl-2-Associated X Protein
  • Cytokines
  • Interferons
  • Interleukin-12