Glucose-6-phosphate dehydrogenase deficiency enhances human coronavirus 229E infection

Abstract

The host cellular environment is a key determinant of pathogen infectivity. Viral gene expression and viral particle production of glucose-6-phosphate dehydrogenase (G6PD)-deficient and G6PD-knockdown cells were much higher than their counterparts when human coronavirus (HCoV) 229E was applied at 0.1 multiplicity of infection. These phenomena were correlated with increased oxidant production. Accordingly, ectopic expression of G6PD in G6PD-deficient cells or addition of antioxidant (such as alpha-lipoic acid) to G6PD-knockdown cells attenuated the increased susceptibility to HCoV 229E infection. All experimental data indicated that oxidative stress in host cells is an important factor in HCoV 229E infectivity.

Figure 1

Elevated viral particle production in glucose-6-phosphate dehydrogenase (G6PD)–deficient cells and protective effect of antioxidants against virus infection at 48 h after infection with human coronavirus (HCoV) 229E. A G6PD activity and Western blot analysis. The indicated A549 vector and G6PD-knockdown cells were harvested for G6PD activity assay and Western blotting of G6PD protein. The activity of G6PD is given in international units per milligram of protein in cell lysate; for infection and plaque assay, an MOI of 0.1 was used to measure virus titer. B and C Viral particle production. Viral particle production was visualized by plaque formation (B) and was higher in G6PD-deficient human foreskin fibroblasts (HFF1) at 24 h after infection than in normal fibroblasts (HFF3). Similar data (C) indicated that viral particle production was higher in G6PD-knockdown A549 cells (A549–5.8, A549–5.18, and A549–5.20) than in control cells (A549–5S-5).Pub _bookmark Command="[Quick Mark]"> D Viral gene (nucleocapsid) expression. Viral gene (nucleocapsid) expression in cells pretreated with an antioxidant, lipoic acid (LA), and in control cells was determined by quantitative polymerase chain reaction at 2, 4, 6, 8, and 10 h after infection with HCoV 229E. Data are mean ± SE values (n=4). **P<.01 for HFF1 vs. HFF3 and for vector-only A549–5S-5 vs. G6PD-knockdown A549–5.8, A549–5.18, or A549–5.20 epithelial cells infected with HCoV 229E) at an MOI of 0.1