Erratum: Staphylococcal Protein A, Panton-Valentine Leukocidin and Coagulase Aggravate the Bone Loss and Bone Destruction in Osteomyelitis

<b><i>Background/Aims: </i></b>Osteomyelitis is a debilitating infectious disease of the bone which is predominantly caused by <i>Staphylococcus aureus (S. aureus)</i>. The purpose of this study was to investigate the role of the <i>S. aureus </i>virulence factors, <i>i.e. </i>protein A (SpA), Panton-Valentine leukocidin (PVL) and coagulase (Coa) on osteomyelitis. <b><i>Methods: </i></b>The effect of SpA, PVL and Coa on osteoblasts was studied through the following aspects including osteoblast proliferation, apoptosis, bone formation, bone mineralization and RANK-L expression. <i>S. aureus </i>overexpressing PVL, SpA or Coa was constructed and used to study the role of PVL, SpA and Coa, respectively. <i>S. aureus </i>silencing PVL, SpA or Coa was also constructed and used for reversing verification. Osteoblast proliferation was detected by MTT tetrazolium dye reduction assay. Apoptosis was determined by Annexin V-FITC staining. The levels of pro-caspase 3, cleaved-caspase 3, pro-caspase 9 and cleaved-caspase 9 were detected by western blot. Bone formation markers including collagen I, osteopontin and osteocalcin were detected by real time RT-PCR. Alkaline phosphatase activity was measured by adding p-nitrophenyl phosphate as a phosphatase substrate. Von kossa stain and alizarin red stain were applied for determining phosphate and calcium deposition, respectively. The RANK-L expression was tested by ELISA. <b><i>Results: </i></b>PVL, SpA and Coa inhibited osteoblast proliferation, induced osteoblast apotosis, prohibited bone formation and mineralization and upregulated RANK-L expression. <b><i>Conclusions: </i></b>PVL, SpA and Coa play a critical role on bone loss and bone destruction of osteomyelitis.