Labisia pumila var. alata reduces bacterial load by inducing uroepithelial cell apoptosis.

ETHNOPHARMACOLOGICAL RELEVANCE: Labisia pumila var. alata (LPva) is a traditional medicinal herb used by Malaysian women to treat many ailments of the genitourinary tract. Its phytoestrogenic properties suggest potential to prevent recurrent urinary tract infection (UTI) in women post menopause. The aim of this study was therefore to investigate the mechanisms of action of LPva in an in vitro model of UTI. MATERIALS AND METHODS: Bladder epithelial cell lines T24 and 5637 and uropathogenic Escherichia coli (UPEC) strain CFT073 were used to model uroepithelial infection. The ability of LPva to induce programmed cell death was tested using the Annexin-V-FLUOS and TUNEL assays. Expression of caveolin-1, ß1 integrin and antimicrobial peptides HBD-2 and LL-37 in response to LPva treatment and/or infection, was assessed using RT real-time PCR. Effects on protein expression were confirmed by Western blot analysis. Sensitivity and yeast agglutination assays were employed to determine if LPva had antimicrobial activities and/or interacted with type 1 fimbriae, respectively. Finally, bacterial adherence and invasion to cells treated with LPva was examined. RESULTS: LPva induced uroepithelial apoptosis which was coupled with upregulated expression of caveolin-1 and downregulation of ß1 integrin. LPva did not exhibit direct antimicrobial properties and did not influence antimicrobial peptide levels in cells. Additionally, LPva did not interact with type 1 fimbriae and did not affect adherence in comparison to non-treated control cells. However, LPva significantly reduced the number of intracellular UPEC in bladder epithelial cells. CONCLUSIONS: Our findings suggest that LPva has beneficial applications against UPEC infection due to its ability to induce programmed cell death and reduce bacterial invasion of the uroepithelium.

Vitamin D induction of the human antimicrobial Peptide cathelicidin in the urinary bladder.

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.