Nitric Oxide Activates IL-6 Production and Expression in Human Renal Epithelial Cells

• Published in: American journal of nephrology Vol. 36; no. 6; pp. 524 - 530
• Main Authors: Demirel, Isak, Vumma, Ravi, Mohlin, Camilla, Svensson, Lovisa, Säve, Susanne, Persson, Katarina
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2012
• Subjects: Anthracenes - pharmacology; Biomedical Sciences; Biomedicinsk vetenskap; Epithelial Cells - metabolism; Epithelial Cells - microbiology; Escherichia coli Infections; Flavonoids - pharmacology; Gene Expression; Humans; IL-6; Imidazoles - pharmacology; Interleukin-1 - biosynthesis; Interleukin-1 - genetics; JNK Mitogen-Activated Protein Kinases - metabolism; Kidney; MAP Kinase Signaling System - drug effects; MAPK signaling; Medicin; Medicine; Nitric oxide; Nitric Oxide - pharmacology; Original Report: Laboratory Investigation; p38 Mitogen-Activated Protein Kinases - metabolism; Protein Kinase Inhibitors - pharmacology; Pyridines - pharmacology; Renal epithelial cells; RNA Stability; RNA, Messenger - metabolism; Urinary tract infections; Urinary tract infections; Renal epithelial cells; Nitric oxide; IL-6; MAPK signaling
• ISSN: 0250-8095; 1421-9670; 1421-9670
• DOI: 10.1159/000345351

Background/Aims: Increased nitric oxide (NO) production or inducible form of NO synthase activity have been documented in patients suffering from urinary tract infection (UTI), but the role of NO in this infection is unclear. We investigated whether NO can affect the host response in human renal epithelial cells by modulating IL-6 production and mRNA expression. Methods: The human renal epithelial cell line A498 was infected with a uropathogenic Escherichia coli (UPEC) strain and/or the NO donor DETA/NO. The IL-6 production and mRNA expression were evaluated by ELISA and real-time RT-PCR. IL-6 mRNA stability was evaluated by analyzing mRNA degradation by real-time RT-PCR. Results: DETA/NO caused a significant (p < 0.05) increase in IL-6 production. Inhibitors of p38 MAPK and ERK1/2 signaling, but not JNK, were shown to significantly suppress DETA/NO-induced IL-6 production. UPEC-induced IL-6 production was further increased (by 73 ± 23%, p < 0.05) in the presence of DETA/NO. The IL-6 mRNA expression increased 2.1 ± 0.17-fold in response to DETA/NO, while the UPEC-evoked increase was pronounced (20 ± 4.5-fold). A synergistic effect of DETA/NO on UPEC-induced IL-6 expression was found (33 ± 7.2-fold increase). The IL-6 mRNA stability studies showed that DETA/NO partially attenuated UPEC-induced degradation of IL-6 mRNA. Conclusions: NO was found to stimulate IL-6 in renal epithelial cells through p38 MAPK and ERK1/2 signaling pathways and also to increase IL-6 mRNA stability in UPEC-infected cells. This study proposes a new role for NO in the host response during UTI by modulating the transcription and production of the cytokine IL-6.