Abstract
Recent data show that increases in bradykinin (BK) concentration contribute to the beneficial effects of angiotensin-converting enzyme inhibitor (ACEI) treatment in chronic kidney disease. However, the possible role of BK in attenuated proteinuria, often seen in ACEI-treated patients, is not well studied. Here, we report that BK decreases mouse podocyte permeability through rearrangement of the tight junction protein zonula occludens-1 (ZO-1) and identify some of the major signaling events leading to permeability change. We show that BK2 receptor (BK2R) stimulation transactivates the epidermal growth factor receptor (EGFR). EGFR transactivation is mediated by a disintegrin and metalloenzyme (ADAM) family members, which are required for both extracellular signal-regulated kinase (ERK) and EGFR activation by BK. Using a gene-silencing approach we observed that both BK-induced ERK activation and BK-induced permeability decrease in podocytes is attenuated by ADAM17 down-regulation, and we identified epiregulin (ER) as the EGFR ligand participating in ADAM-dependent BK2R-EGFR cross-talk. EGFR inhibition attenuated both ZO-1 rearrangement and BK-induced permeability decreases in podocyte. We propose that ZO-1 redistribution is an important element of BK-induced permeability change and the signaling events involved in ZO-1 rearrangement include transactivation of the EGFR via ADAM17 activation and ER shedding. Our data indicate that ADAM17 and the EGFR may be potential novel therapeutic targets in diabetic nephropathy and other chronic kidney diseases.
Footnotes
This work was supported by the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases [Grants 5K01-DK070054, 3K01-DK070054-S1 (to M.G.), R01-DK055524 (to L.M.L.), R01-DK52448 (to J.R.R.)], the National Institutes of Health National Institute of General Medical Sciences [Grant R01-GM63909 ] (to J.R.R.); the Paul Teschan Research Fund of the Dialysis Clinic, Inc. (to M.G.); the Medical University of South Carolina Summer Health Professions Research Program (to D.B.S.); and Veteran Administration Research Services [Merit Award 1I0 1BX000182-01 and a Research Enhancement Award Program grant] (to J.R.R.).
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.110.168054.
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ABBREVIATIONS:
- BK
- bradykinin
- BK2R
- BK B2 receptor
- ZO-1
- zonula occludens-1
- ADAM
- a disintegrin and metalloenzyme
- EGF
- epidermal growth factor
- EGFR
- EGF receptor
- pEGFR
- phosphorylated EGFR
- tEGFR
- total EGFR
- HB-EGF
- heparin-binding EGF
- ANGII
- angiotensin II
- ER
- epiregulin
- ERK
- extracellular signal-regulated kinase
- pERK
- phosphorylated ERK
- tERK
- total ERK
- FBS
- fetal bovine serum
- FITC
- fluorescein isothiocyanate
- BSA
- bovine serum albumin
- GPCR
- G protein-coupled receptor
- GM6001
- N-[(2R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl]-l-tryptophan methylamide
- GM negative control
- N-t-butoxycarbonyl-l-leucyl-l-tryptophan methylamide
- AG1478
- N-(3-chlorophenyl)-6,7-dimethoxy-4-quinazolinamine
- TGF-α
- transforming growth factor α
- ACE
- angiotensin-converting enzyme
- ACEI
- ACE inhibitor
- siRNA
- small interfering RNA
- MMP
- matrix metalloproteinase
- HOE140
- dArg-Arg-Pro-Hyp-Gly-Thi-Ser-dTic-Oic-Arg
- GAPDH
- glyceraldehyde 3-phosphate dehydrogenase
- DMSO
- dimethyl sulfoxide.
- Received March 10, 2010.
- Accepted June 18, 2010.
- U.S. Government work not protected by U.S. copyright
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