title: The Staphylococcus aureus extracellular adherence protein promotes bacterial internalization by keratinocytes independent of fibronectin-binding proteins.
abstract: Staphylococcus aureus, the leading causal pathogen of skin infections, is strongly associated with skin atopy, and a number of bacterial adhesins allow the microbe to adhere to and invade eukaryotic cells. One of these adhesive molecules is the multifunctional extracellular adherence protein (Eap), which is overexpressed in situ in authentic human wounds and was shown to delay wound healing in experimental models. Yet, its role during invasion of keratinocytes is not clearly defined. By using a gentamicin/lysostaphin protection assay we demonstrate here that preincubation of HaCaT cells or primary keratinocytes with Eap results in a concentration-dependent significant increase in staphylococcal adhesion, followed by an even more pronounced internalization of bacteria by eukaryotic cells. Flow cytometric analysis revealed that Eap increased both the number of infected eukaryotic cells and the bacterial load per infected cell. Moreover, treatment of keratinocytes with Eap strongly enhanced the internalization of coagulase-negative staphylococci, as well as of E. coli, and markedly promoted staphylococcal invasion into extended-culture keratinocytes, displaying expression of keratin 10 and involucrin as differentiation markers. Thus, wound-related staphylococcal Eap may provide a major cellular invasin function, thereby enhancing the pathogen's ability to hide from the host immune system during acute and chronic skin infection.
authors: Institute for Medical Microbiology and Hygiene, University of Saarland Medical Center, Homburg, Germany.
authors: Stephanie
authors: S
authors: Bur
authors: Klaus T
authors: KT
authors: Preissner
authors: Mathias
authors: M
authors: Herrmann
authors: Markus
authors: M
authors: Bischoff
mesh_terms: D000208:Acute Disease; D018829:Adhesins, Bacterial / Q000378:metabolism; D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D002461:Cell Line, Transformed; D002908:Chronic Disease; D004705:Endocytosis / Q000502:physiology; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*; D061251:Primary Cell Culture; D016601:RNA-Binding Proteins / Q000378:metabolism*; D013207:Staphylococcal Skin Infections / Q000276:immunology* / Q000378:metabolism; D013211:Staphylococcus aureus / Q000254:growth & development / Q000378:metabolism*; D014945:Wound Healing / Q000502:physiology
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; C444739:Eap-N protein, Staphylococcus aureus; D005353:Fibronectins; D016601:RNA-Binding Proteins; C078635:fibronectin-binding proteins, bacterial