title: Interaction of the EGF Receptor and the Hippo Pathway in the Diabetic Kidney.
abstract: Activation of the EGF receptor (EGFR) or the Hippo signaling pathway can control cell proliferation, apoptosis, and differentiation, and the dysregulation of these pathways can contribute to tumorigenesis. Previous studies showed that activation of EGFR signaling in renal epithelial cells can exacerbate diabetic kidney injury. Moreover, EGFR has been implicated in regulating the Hippo signaling pathway in Drosophila; thus, we examined this potential interaction in mammalian diabetic kidney disease. Yes-associated protein (YAP) is a transcriptional regulator regulated by the Hippo signaling pathway. We found YAP protein expression and phosphorylation were upregulated in diabetic mouse renal proximal tubule epithelial cells, which were inhibited in diabetic proximal tubule EGFR-knockout mice (EGFR(ptKO)) or administration of an EGFR tyrosine kinase inhibitor erlotinib. Furthermore, activation of an EGFR-PI3K-Akt-CREB signaling pathway mediated YAP gene expression and YAP nuclear translocation and interaction with the TEA domain (TEAD) transcription factor complex, which led to upregulated expression of two TEAD-dependent genes, the connective tissue growth factor and amphiregulin genes. In a renal proximal tubule cell line, either pharmacologic or genetic inhibition of EGFR, Akt, or CREB blunted YAP expression in response to high-glucose treatment. Additionally, knocking down YAP expression by specific siRNA inhibited cell proliferation in response to high glucose or exogenous EGF. Therefore, these results link the Hippo pathway to EGFR-mediated renal epithelial injury in diabetes.
authors.affiliation: Department of Veterans Affairs, Nashville, Tennessee; and Department of Medicine and Jian-chun.chen@vanderbilt.edu ray.harris@vanderbilt.edu.
authors.forename: Jianchun
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Veterans Affairs, Nashville, Tennessee; and Department of Medicine and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee Jian-chun.chen@vanderbilt.edu ray.harris@vanderbilt.edu.
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Harris
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003928:Diabetic Nephropathies / Q000473:pathology*; D066246:ErbB Receptors / Q000502:physiology*; D000090683:Hippo Signaling Pathway; D006801:Humans; D007668:Kidney / Q000473:pathology*; D008297:Male; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D066246:ErbB Receptors; D017346:Protein Serine-Threonine Kinases
keywords: cell signaling; diabetic nephropathy; epidermal growth factor