Spike protein of SARS-CoV stimulates cyclooxygenase-2 expression via both calcium-dependent and calcium-independent protein kinase C pathways.
We have previously shown that the nucleocapsid protein of SARS-associated coronavirus (SARS-CoV) activated cyclooxygenase-2 (COX-2) expression. In this study, we identified another viral protein, the spike of SARS-CoV, which played an important role in virus-stimulated COX-2 expression after screening all genes from the SARS-CoV genome. We found that an upstream calcium-dependent PKC isozyme PKC alpha that modulates the downstream ERK/NF-kappaB pathway through an influx of extracellular Ca2+ is induced by the spike protein of SARS-CoV. The ERK/NF-kappaB was identified to be involved in the activation of COX-2 promoter and production of COX-2 protein in HEK293T cells. We also demonstrated that another unusual pathway, the calcium-independent PI3K/PKC epsilon/JNK/CREB pathway, functioned in cooperation with the calcium-dependent pathway to induce COX-2 expression upon stimulation by spike protein. This pathway can be blocked by PKC epsilon-specific, small interfering RNA, PI3K/JNK kinase-specific inhibitors as well as dominant negative JNK. PKC epsilon-specific siRNA also attenuated the phosphorylation of JNK. Our results provide evidence that helps us understand the function of SRAS-CoV spike protein in SARS pathogenesis.
Liu
Mo
M
State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.
Yang
Yongbo
Y
Gu
Chunfang
C
Yue
Yinpu
Y
Wu
Kenneth K
KK
Wu
Jianguo
J
Zhu
Ying
Y
D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002522:Chlorocebus aethiops; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000502:physiology*; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045473:Severe acute respiratory syndrome-related coronavirus / Q000737:chemistry*; D064370:Spike Glycoprotein, Coronavirus; D015533:Transcriptional Activation; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000502:physiology*
D017931:DNA Primers; D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; D051546:Cyclooxygenase 2; D011493:Protein Kinase C; D002118:Calcium