Department of Microbiology, Tumor and Cell Biology, Division of Clinical Microbiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden.
PLoS One. 2010 Dec 14;5(12):e15580. doi: 10.1371/journal.pone.0015580.
The urinary tract is frequently being exposed to potential pathogens and rapid defence mechanisms are therefore needed. Cathelicidin, a human antimicrobial peptide is expressed and secreted by bladder epithelial cells and protects the urinary tract from infection. Here we show that vitamin D can induce cathelicidin in the urinary bladder. We analyzed bladder tissue from postmenopausal women for expression of cathelicidin, before and after a three-month period of supplementation with 25-hydroxyvitamin D3 (25D3). Cell culture experiments were performed to elucidate the mechanisms for cathelicidin induction. We observed that, vitamin D per se did not up-regulate cathelicidin in serum or in bladder tissue of the women in this study. However, when the bladder biopsies were infected with uropathogenic E. coli (UPEC), a significant increase in cathelicidin expression was observed after 25D3 supplementation. This observation was confirmed in human bladder cell lines, even though here, cathelicidin induction occurred irrespectively of infection. Vitamin D treated bladder cells exerted an increased antibacterial effect against UPEC and colocalization to cathelicidin indicated the relevance of this peptide. In the light of the rapidly growing problem of resistance to common urinary tract antibiotics, we suggest that vitamin D may be a potential complement in the prevention of UTI.
尿路经常暴露于潜在的病原体中，因此需要快速的防御机制。Cathelicidin 是一种人类抗菌肽，由膀胱上皮细胞表达和分泌，可防止尿路感染。在这里，我们表明维生素 D 可以诱导膀胱中的 Cathelicidin。我们分析了绝经后妇女的膀胱组织，以检测 Cathelicidin 的表达，在补充 25-羟维生素 D3（25D3）三个月前后。进行了细胞培养实验以阐明 Cathelicidin 诱导的机制。我们观察到，维生素 D 本身并不能上调本研究中女性血清或膀胱组织中的 Cathelicidin。然而，当膀胱活检被尿路致病性大肠杆菌（UPEC）感染时，在 25D3 补充后观察到 Cathelicidin 表达显著增加。在人膀胱细胞系中也证实了这一观察结果，尽管在这里，Cathelicidin 的诱导与感染无关。用维生素 D 处理的膀胱细胞对 UPEC 具有增强的抗菌作用，并且 Cathelicidin 的共定位表明了该肽的相关性。鉴于对常见尿路感染抗生素的耐药性问题迅速增加，我们认为维生素 D 可能是预防尿路感染的潜在补充剂。
