Otte Jan-Michel, Werner Ilka, Brand Stephan, Chromik Ansgar M, Schmitz Frank, Kleine Michael, Schmidt Wolfgang E
Department of Internal Medicine I, St. Josef-Hospital, Ruhr-University, Bochum, Germany.
J Cell Biochem. 2008 Aug 15;104(6):2286-97. doi: 10.1002/jcb.21787.
Limiting microbial threats, maintenance and re-establishment of the mucosal barrier are vital for intestinal homeostasis. Antimicrobial peptides have been recognized as essential defence molecules and decreased expression of these peptides has been attributed to chronic inflammation of the human intestinal mucosa. Recently, pluripotent properties, including stimulation of proliferation and migration have been suggested for a number of antimicrobial peptides. However, it is currently unknown, whether the human beta-defensin 2 (hBD-2) in addition to its known antimicrobial properties has further effects on healing and protection of the intestinal epithelial barrier. Caco-2 and HT-29 cells were stimulated with 0.1-10 microg/ml hBD-2 for 6-72 h. Effects on cell viability and apoptosis were monitored and proliferation was quantified by bromo-deoxyuridine incorporation. Migration was quantified in wounding assays and characterized by immunohistochemistry. Expression of mucins was determined by quantitative PCR and slot-blot analysis. Furthermore, anti-apoptotic capacities of hBD-2 were studied. Over a broad range of concentrations and stimulation periods, hBD-2 was well tolerated by IECs and did not induce apoptosis. hBD-2 significantly increased migration but not proliferation of intestinal epithelial cells. Furthermore, hBD-2 induced cell line specific the expression of mucins 2 and 3 and ameliorated TNF-related apoptosis-inducing ligand (TRAIL) induced apoptosis. In addition to its known antimicrobial properties, hBD-2 might have further protective effects on the intestinal epithelium. Results of this in vitro study suggest, that hBD-2 expression may play a dual role in vivo, i.e. in impaired intestinal barrier function observed in patients with inflammatory bowel disease.
限制微生物威胁、维持和重建黏膜屏障对于肠道稳态至关重要。抗菌肽已被公认为重要的防御分子，这些肽的表达降低被认为与人类肠道黏膜的慢性炎症有关。最近，一些抗菌肽被认为具有多能特性，包括刺激增殖和迁移。然而，目前尚不清楚人类β-防御素2（hBD-2）除了其已知的抗菌特性外，是否对肠道上皮屏障的愈合和保护还有其他作用。用0.1 - 10微克/毫升的hBD-2刺激Caco-2和HT-29细胞6 - 72小时。监测对细胞活力和凋亡的影响，并通过溴脱氧尿苷掺入法对增殖进行定量。在创伤实验中对迁移进行定量，并通过免疫组织化学进行表征。通过定量PCR和狭缝印迹分析确定黏蛋白的表达。此外，还研究了hBD-2的抗凋亡能力。在广泛的浓度和刺激时间范围内，IECs对hBD-2耐受性良好，且未诱导凋亡。hBD-2显著增加肠道上皮细胞的迁移，但不增加其增殖。此外，hBD-2诱导细胞系特异性表达黏蛋白2和3，并改善肿瘤坏死因子相关凋亡诱导配体（TRAIL）诱导的凋亡。除了其已知的抗菌特性外，hBD-2可能对肠道上皮还有进一步的保护作用。这项体外研究的结果表明，hBD-2的表达在体内可能起双重作用，即在炎症性肠病患者中观察到的肠道屏障功能受损的情况下。
