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M and N proteins of SARS coronavirus induce apoptosis in HPF cells

Abstract

Background: SARS-associated coronavirus (SARS-CoV) induced cell apoptosis and its structural proteins may play a role in this process. Objectives: To determine whether the structural proteins M and N of SARS-CoV induce apoptosis. Study design: We investigated human pulmonary fibroblast (HPF) cells, were transfected with plasmids containing the M or N gene, by TdT-mediated dUTP nick end labeling (TUNEL), Hoechst 33342 staining for nuclei, and observation of morphology. Results: We found that in the absence of serum about 16.34% of cells transfected by pcDNA3.1-M and 21.72% of N-transfected cells showed typical apoptotic characteristics, significantly different from mock-transfected cells (only 6.23%, p<0.01). Furthermore, the cells that were co-transfected with M and N proteins showed more obvious phenomena of cell death (about 36.03%). There was a statistical significance between M-transfected cells and co-transfected cells (p<0.01), and a remarkable difference between N-transfected cells and co-transfected cells (p<0.01). Conclusions: The results show that M and N proteins of SARS-CoV can induce apoptosis of HPF cells. Co-transfection of M and N enhances the induction of apoptosis by M or N alone, which also suggests that the structural proteins of SARS-CoV may play an important role not only in the process of invasion but also in the pathogenetic process in cells.

Abbreviations

HPF:

human pulmonary fibroblast

SARS:

severe acute respiratory syndrome

SARS-CoV:

SARS-associated coronavirus

TUNEL:

TdT-mediated dUTP nick end labeling

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Correspondence to Jing-Pian Peng.

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Zhao, G., Shi, S., Yang, Y. et al. M and N proteins of SARS coronavirus induce apoptosis in HPF cells. Cell Biol Toxicol 22, 313–322 (2006). https://doi.org/10.1007/s10565-006-0077-1

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Keywords

  • apoptosis
  • human pulmonary fibroblasts
  • SARS-CoV