Abstract
BackgroundThe disintegrin and metalloenzyme ADAM17 participates in numerous inflammatory and proliferative diseases, and its pathophysiological role was implicated in kidney fibrosis, polycystic kidney disease and other chronic kidney diseases. At present, we have little understanding how the enzyme activity is regulated. In this study we wanted to characterize the role of α5β1 integrin in ADAM17 activity regulation during G protein-coupled receptor (GPCR) stimulation.Methodology/Principal FindingsWe showed previously that the profibrotic GPCR agonist serotonin (5-HT) induced kidney mesangial cell proliferation through ADAM17 activation and heparin-binding epidermal growth factor (HB-EGF) shedding. In the present studies we observed that in unstimulated mesangial cell lysates α5β1 integrin co-precipitated with ADAM17 and that 5-HT treatment of the cells induced dissociation of α5β1 integrin from ADAM17. Using fluorescence immunostaining and in situ proximity ligation assay, we identified the perinuclear region as the localization of the ADAM17/α5β1 integrin interaction. In cell-free assays, we showed that purified α5β1 integrin and β1 integrin dose-dependently bound to and inhibited activity of recombinant ADAM17. We provided evidence that the conformation of the integrin determines its ADAM17-binding ability. To study the effect of β1 integrin on ADAM17 sheddase activity, we employed alkaline phosphatase-tagged HB-EGF. Overexpression of β1 integrin lead to complete inhibition of 5-HT-induced HB-EGF shedding and silencing β1 integrin by siRNA significantly increased mesangial cells ADAM17 responsiveness to 5-HT.Conclusions/SignificanceOur data show for the first time that β1 integrin has an important physiological role in ADAM17 activity regulation. We suggest that regulating α5β1 integrin binding to ADAM17 could be an attractive therapeutic target in chronic kidney diseases.
Highlights
ADAM17, one of the most intensively studied member of the disintegrin and metalloenzyme family was identified as the protease which cleaves the cell-surface-bound form of the inflammatory cytokine, pro-tumor necrosis factor (TNF)a [1,2]
ADAM17 participates in protein ectodomain shedding of epidermal growth factor (EGF) receptor ligands such as heparin-binding EGF (HBEGF), transforming growth factor (TGF)a, and amphiregulin which, in turn, activate the EGF receptor (EGFR) and initiate downstream signaling events leading to cell proliferation, migration, or apoptosis
We show that G protein-coupled receptor (GPCR) stimulation leads to ADAM17/a5b1 integrin complex dissociation, which releases the enzyme activity and contributes to heparin-binding epidermal growth factor (HB-EGF) shedding in mesangial cells
Summary
ADAM17, one of the most intensively studied member of the disintegrin and metalloenzyme family was identified as the protease which cleaves the cell-surface-bound form of the inflammatory cytokine, pro-tumor necrosis factor (TNF)a [1,2]. ADAM17 participates in protein ectodomain shedding of epidermal growth factor (EGF) receptor ligands such as heparin-binding EGF (HBEGF), transforming growth factor (TGF)a, and amphiregulin which, in turn, activate the EGF receptor (EGFR) and initiate downstream signaling events leading to cell proliferation, migration, or apoptosis (see recent review [8]). We showed that the pro-fibrotic GPCR agonist serotonin (5-HT) induces proliferation of kidney mesangial cells through EGFR transactivation. All of the above described processes: inflammation, apoptosis, cell proliferation, and angiogenesis have important pathophysiological role in the development of chronic kidney diseases [13,14,15,16]. In this study we wanted to characterize the role of a5b1 integrin in ADAM17 activity regulation during G protein-coupled receptor (GPCR) stimulation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
