2. Host defense (Antimicrobial) peptide, human β-defensin-3, improves the function of the epithelial tight-junction barrier in human keratinocytes
Chanisa Kiatsurayanon, François Niyonsaba, Rithee Smithrithee, Toshihiro Akiyama, Hiroko Ushio, Mutsuko Hara, Ko Okumura, Shigaku Ikeda, Hideoki Ogawa J Invest Dermatol. 2014 Aug;134(8):2163-2173. doi: 10.1038/jid.2014.143. Epub 2014 Mar 14.
Human β-defensins (hBDs) are host defense peptides that not only exhibit microbicidal properties but also stimulate various cellular activities, including keratinocyte proliferation, migration, and wound healing. hBDs are overexpressed in the skin in cases of psoriasis but are downregulated in atopic dermatitis skin, although both diseases are associated with stratum corneum barrier defects. Because the tight-junction (TJ) barrier is also dysfunctional in both atopic dermatitis and psoriasis patients, we hypothesized that hBDs may regulate the TJ barrier function in keratinocytes. We observed that, among the hBDs tested, only hBD-3 increased the expression of several claudins and their localization along the cell-cell borders. In addition, hBD-3 elevated the transepithelial electrical resistance and reduced the paracellular permeability of keratinocyte layers, and this effect was reversed by the claudin inhibitor ochratoxin A, CCR6 antibody, and CCR6 small interfering RNA. Moreover, hBD-3 enhanced the activation of Rac1, atypical protein kinase C, glycogen synthase kinase-3, and phosphatidylinositol 3 kinase, which are required for the hBD-3-mediated regulation of the TJ barrier function, as evidenced by the effects of their respective inhibitors. Collectively, our findings provide evidence regarding the contribution of host defense peptides to the innate immunity of skin by regulating TJ barrier function, in addition to their antimicrobial and other immunomodulatory activities.
3. Suppression of interleukin (IL)-8 and human beta defensin-2 secretion in LPS-and/or IL-1β-stimulated airway epithelial A549 cells by a herbal formulation against respiratory infections (BNO 1030)
Katarina Hostanska, Joerg Melzer, Annette Amon, Reinhard Saller J Ethnopharmacol. 2011 Mar 24;134(2):228-33. doi: 10.1016/j.jep.2010.12.006. Epub 2010 Dec 16.
Aim of the study: A special ethanolic-aqueous extract from seven traditional medicinal plants (BNO 1030) has been used for several decades to treat recurrent infections of the respiratory tract. Considering the potential role of interleukin-8 (IL-8) and human beta defensin-2 (hBD-2) in inflammation, we investigated the effect of BNO 1030 on lipopolysaccharide (LPS) from Pseudomonas aeruginosa or IL-1β-induced inflammatory mediators in A549 human type II alveolar epithelial cells. Materials and methods: A549 cells were stimulated with LPS (100 μg/ml) or IL-1β (50 ng/ml) in the presence of the preparation and the secretion of IL-8 and hBD-2 were measured after 18 h and 24h in cell free supernatants using enzyme-linked immunosorbent assays (ELISA). Cell viability and cell growth was investigated by propidium iodide uptake and WST-1 assay, respectively. Results: BNO 1030 inhibited the secretion of IL-8 and hBD-2 at non-cytotoxic concentrations (0.1-100 μg/ml; cell growth inhibitory concentration, 50% (IC(50))=678 ± 87.6 μg/ml). Stimulation by IL-1β led to a 7-fold activation of IL-8 secretion, which was reduced by 37.7 ± 4.1% (p<0.05) after incubation with 100 μg/ml BNO 1030. Inducible hBD-2 was suppressed by 91.8 ± 15.6% (p<0.01) at the same concentration of BNO 1030 (IC(50)=0.7 ± 0.1 μg/ml). The 2-fold increase of IL-8 secretion by LPS-stimulated cells was completely abolished at concentration of 50 μg/ml BNO 1030 (IC(50)=5.7±3.6 μg/ml). Conclusion: BNO 1030 suppressed the secretion of IL-8 and hBD-2 in cultured epithelial A549 cells. These results support its use as a phytotherapeutic product prepared from traditional remedies in inflammatory diseases, especially those affecting the respiratory tract.
