Growth factor-mediated phosphorylation of proapoptotic BAD reduces tubule cell death in vitro and in vivo
| Autor: | Barbara A. Thornhill, Susan C. Kiley, Robert L. Chevalier, Julie R. Ingelfinger, Shiow-Shih Tang |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
medicine.medical_specialty
Programmed cell death medicine.medical_treatment 030232 urology & nephrology In Vitro Techniques Biology ureteral obstruction Kidney Tubules Proximal 03 medical and health sciences 0302 clinical medicine Somatomedins Epidermal growth factor In vivo Internal medicine Hydrostatic Pressure medicine Animals Phosphorylation Cell Line Transformed 030304 developmental biology 0303 health sciences TUNEL assay Growth factor apoptosis mechanical stress p42 MAP kinase Rats 3. Good health Cell biology Endocrinology epidermal growth factor Apoptosis Nephrology bcl-Associated Death Protein Signal transduction Carrier Proteins Signal Transduction |
| Zdroj: | Kidney International. 63(1):33-42 |
| ISSN: | 0085-2538 |
| DOI: | 10.1046/j.1523-1755.2003.00706.x |
| Popis: | Growth factor-mediated phosphorylation of proapoptotic BAD reduces tubule cell death in vitro and in vivo.BackgroundExogenous growth factors administered during unilateral ureteral obstruction (UUO) in neonatal rats significantly reduce apoptosis and tubular atrophy. Because the mechanism underlying these salutary effects is largely unknown, we investigated signaling pathways potentially activated by growth factors to determine their roles in therapeutic action.MethodsMechanical strain was applied to confluent cultures of immortalized rat proximal tubule cells to simulate obstruction-induced stretch injury in vivo. Growth factors, inhibitory antibodies or pharmacological inhibitors were added to cultures that were subsequently processed for TUNEL analysis or immunoblots to identify signaling pathways that could be modulating cell survival. For in vivo studies, kidneys harvested from rats ± UUO ± epidermal growth factor (EGF) were fixed or frozen for immunohistochemistry or immunoblot analysis.ResultsTreatment with EGF or insulin-like growth factor-1 (IGF-1) during stretch decreased apoptosis by 50% (P < 0.001). Neutralizing antibodies (Abs) directed against either growth factor or its receptor blocked the reduction in apoptosis. Stretch decreased BAD phosphorylation by ∼50% (P < 0.001) relative to unstretched cells and each growth factor restored phosphorylation to basal levels. Kinase-specific inhibitors that blocked growth factor-mediated BAD phosphorylation promoted apoptosis in vitro. BAD phosphorylation decreased by ∼50% (P < 0.001) in the tubules of obstructed hydronephrotic rat kidneys and administration of EGF restored BAD phosphorylation to basal levels.ConclusionsSignaling pathways converging at BAD phosphorylation are key to growth factor-mediated attenuation of stretch-induced apoptosis in vitro and in vivo. |
| Databáze: | OpenAIRE |
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