To reveal pharmacological targets and molecular mechanisms of curcumol against interstitial cystitis

Abstract

This study was designed to reveal the predictive targets and biological mechanisms of curcumol against interstitial cystitis (IC). By use of available databases and bioinformatic assays, pathogenetic targets of IC and functional targets of curcumol were identified respectively. A network of functional protein-protein interaction (PPI) was produced before screening the main predictive targets, biological processes and signaling pathways of curcumol against IC. In bioinformatic findings, the data of ingenuity pathway analysis (IPA) delineated that curcumol exerted anti-IC benefits through regulating multipronged signaling pathways, including tyrosine protein kinase-2 (PTK2) pathway. Further, optimal 18 biotargets of curcumol against IC were harvested through differential expression analysis. And the predictive targets of receptor tyrosine-protein kinase erbB-2 (ERBB2), epidermal growth factor receptor (EGFR) and PTK2 were the most important molecules. In further validated experiments, PTK2 and phosphorylation PTK2 (p-PTK2) were representatively selected for testing by human and animal IC samples. As results, increased immunoreactive proteins of tumor necrosis factor alpha (TNF-α), PTK2 and p-PTK2^Tyr397 in human IC sections were observed, accompanied with altered urinary parameters. Interestingly, curcumol-treated IC mice showed that intracellular expressions of PTK2, p-PTK2^Tyr397 in bladder samples were reduced, accompanied with lowered blood inflammatory cytokines of interleukin 6 (IL-6), TNF-α. In conclusion, the current bioinformatic data and preliminary findings unravel that the predominant targets of curcumol against IC may be the potential biological markers for screening and treating IC, such as PTK2 molecule.

Keywords: Bioinformatics; Biomarkers; Curcumol; Interstitial cystitis; PTK2; protein-protein interaction.

Graphical abstract

Fig. 1

This study used bioinformatic assays to predict the main biotargets and molecular pathways of curcumol against IC, followed by experimental validation.

Fig. 2

A PPI network was used to construct the targets of curcumol against IC (Red nodes) and functional related targets (Green nodes) before the main targets were identified and collected.

Fig. 3

After being analyzed, the main targets of curcumol against IC were identified and correlated. As a result, 3 top targets were representatively found as ERBB2, EGFR and PTK2 prior to further validation.

Fig. 4

After data analyses in DAVID tool, top 20 biological processes and signaling pathways of curcumol against IC were showed respectively prior to further bioinformatic discussion.

Fig. 5

Clinical characteristics of patients with IC. As results, medical CT scans showed urocystic lesions with chronic cystitis, urinary tract infection. Further, immunohistochemical staining showed visible expression of cellular TNF-α in IC sections. And the immunofluorescent stains displayed increased expressions of PTK2, p-PTK2^Tyr397 in IC sections.

Fig. 6

Anti-IC activities of curcumol on CPS-lesioned mice. As showed in HE stains, CPS-lesioned mice resulted in morphological changes in bladder tissues. And increased expression of intracellular TNF-α in the bladder were observed in CPS-lesioned mice by using immunohistochemical stain. Interestingly, curcumol-treated mice showed bladder morphological improvement, and reduced TNF-α expression. As showed in immunofluorescence staining, CPS-lesioned mice resulted in elevated PTK2, p-PTK2^Tyr397 expressions in bladder sections. However, down-regulated expressions of TNF-α, PTK2, p-PTK2^Tyr397 in the bladder cells of curcumol-treated mice were observed, accompanied with ameliorative histomorphology in bladder tissues.