Increased cell apoptosis of urothelium mediated by inflammation in interstitial cystitis/painful bladder syndrome.
OBJECTIVE
To investigate whether bladder inflammation could directly modulate the signaling pathway of increased urothelial cell apoptosis in interstitial cystitis/painful bladder syndrome (IC/PBS). Chronic inflammation and impaired urothelial homeostasis are possible pathogenesis of IC/PBS.


METHODS
A total of 29 patients with IC/PBS and 5 control patients were enrolled in the present study. Double stain, protein array analysis, and Western blotting were performed to analyze the alterations of caspase 3, Bad, Bax, phospho-p53, phospho-p38α, and tumor necrosis factor-α (TNF-α) in bladder mucosa specimens from patients with IC/PBS and control patients. The intensities of the proteins in the arrays and Western blots were quantified using ImageJ processing. Inflammatory molecule-treated urothelial cells were analyzed using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining and Western blotting for the level of molecules involved in apoptosis.


RESULTS
Phospho-p38 and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling double staining indicated that inflammatory and apoptotic events coexisted in the IC/PBS bladder. Protein-antibody array analysis showed that several inflammatory molecules were increased in the IC/PBS samples. We also found that the levels of pro-apoptotic proteins, including phospho-p53 (Ser 15), Bad, Bax, and cleaved caspase-3 were significantly increased in the IC/PBS bladders. These results were confirmed by immunoblotting and suggested that the tissue damage and abnormal urothelium in the IC/PBS bladder might be regulated concurrently by inflammatory signals, such as p38 mitogen-activated protein kinase and TNF-α. The in vitro analysis also showed that the apoptotic process could be induced by TNF-α treatment and anisomycin stimulation in normal urothelial cells.


CONCLUSIONS
Apoptosis of urothelial cells in patients with IC/PBS could result from upregulation of inflammatory signals, including p38 mitogen-activated protein kinase and TNF-α.
Department of Urology, Buddhist Tzu Chi General Hospital and Tzu Chi University, Hualien, Taiwan.
Jia-Heng
JH
Shie
Hsin-Tzu
HT
Liu
Hann-Chorng
HC
Kuo
D000841:Anisomycin / Q000494:pharmacology; D017209:Apoptosis; D053148:Caspase 3 / Q000096:biosynthesis / Q000235:genetics; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D018856:Cystitis, Interstitial / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation; D048308:Mitogen-Activated Protein Kinase 14 / Q000378:metabolism; D009092:Mucous Membrane / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D015854:Up-Regulation; D014550:Urinary Incontinence, Stress / Q000378:metabolism / Q000473:pathology; D019459:Urothelium / Q000378:metabolism / Q000473:pathology*; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis / Q000235:genetics; D051025:bcl-Associated Death Protein / Q000096:biosynthesis / Q000235:genetics
C494819:BAD protein, human; C494826:BAX protein, human; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D000841:Anisomycin; D048308:Mitogen-Activated Protein Kinase 14; C505407:CASP3 protein, human; D053148:Caspase 3