Biofilm Propensity of Staphylococcus aureus Skin Isolates is Associated with Increased Severity and Barrier Dysfunction in the Mechanisms of the Progression of Atopic Dermatitis to Asthma in Children (MPAACH) Cohort

Abstract

RATIONALE: IgE plays a central role in the development of allergic rhinitis (AR). Although endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of allergic airway diseases, such as asthma, its role in AR is poorly studied. METHODS: Real-time PCR, immunohistochemistry and western blot analysis were applied to detect the expression of ER stress markers GRP78, CHOP, ATF6a, XBP-1, its splice variant (sXBP-1), and p-eIF2a in nasal tissue samples from control subjects and AR patients. Immunostaining of serial tissue sections were performed to detect the cellular sources of GRP78 and CHOP. Nasal explant tissues from AR patients were cultured ex vivo and secretion of IgE to culture supernatants were measured. RESULTS: Compared to control tissues, the mRNA and protein expression of ER stress markers GRP78 , CHOP, ATF6a, XBP-1, sXBP-1, and p-eIF2a were all significantly up-regulated in nasal tissues from AR patients compared to control tissues as detected by RT-PCR, immunohistochemistry and western blot analysis. The immunoreactivity of GRP78 and CHOP were mainly located in CD138 + plasma cells in lamina propria in nasal tissues. The numbers of GRP78 and CHOP positive cells correlated with the numbers of plasma cells and IgE + plasma cells. In addition, after treated with 4-Phenylbutyric acid (4-PBA), an ER stress inhibitor, the mRNA and protein levels of GRP78, CHOP, ATF6a, XBP-1, sXBP-1, and p-eIF2a were down-regulated in nasal explant tissues and IgE levels were reduced in culture supertanants. CONCLUSIONS: The ER stress may be invovled in the regulation of local IgE secretion from plasma cells in AR patients.

Variation in Biofilm-Forming Potential of Staphylococcus aureus from Clinical and Non-Clinical Sources

“…These biofilms are notable as an important contributor to virulence abilities, further aiding the producing strain in long term survival and resistance to antimicrobial agents [16][17][18][19]. Biofilm forming ability has even further been described as a potential marker of pathogenicity particularly in S. aureus [14,20]. Of all the studies corroborating these facts, few have been carried out in Africa with only a handful of studies exploring biofilm forming potential with relation to source of isolates in Nigeria.…”