Inhibition of Src kinase blocks high glucose-induced EGFR transactivation and collagen synthesis in mesangial cells and prevents diabetic nephropathy in mice.
Chronic exposure to high glucose leads to diabetic nephropathy characterized by increased mesangial matrix protein (e.g., collagen) accumulation. Altered cell signaling and gene expression accompanied by oxidative stress have been documented. The contribution of the tyrosine kinase, c-Src (Src), which is sensitive to oxidative stress, was examined. Cultured rat mesangial cells were exposed to high glucose (25 mmol/L) in the presence and absence of Src inhibitors (PP2, SU6656), Src small interfering RNA (siRNA), and the tumor necrosis factor-α-converting enzyme (TACE) inhibitor, TAPI-2. Src was investigated in vivo by administration of PP2 to streptozotocin (STZ)-induced diabetic DBA2/J mice. High glucose stimulated Src, TACE, epidermal growth factor receptor (EGFR), mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase (ERK1/2, p38), and collagen IV accumulation in mesangial cells. PP2 and SU6656 blocked high glucose-stimulated phosphorylation of Src Tyr-416, EGFR, and MAPKs. These inhibitors and Src knockdown by siRNA, as well as TAPI-2, also abrogated high glucose-induced phosphorylation of these targets and collagen IV accumulation. In STZ-diabetic mice, albuminuria, increased Src pTyr-416, TACE activation, ERK and EGFR phosphorylation, glomerular collagen accumulation, and podocyte loss were inhibited by PP2. These data indicate a role for Src in a high glucose-Src-TACE-heparin-binding epidermal growth factor-EGFR-MAPK-signaling pathway to collagen accumulation. Thus, Src may provide a novel therapeutic target for diabetic nephropathy.
Toronto General Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada.
Kanta
K
Taniguchi
Ling
L
Xia
Howard J
HJ
Goldberg
Ken W K
KW
Lee
Anu
A
Shah
Laura
L
Stavar
Elodie A Y
EA
Masson
Abdul
A
Momen
Eric A
EA
Shikatani
Rohan
R
John
Mansoor
M
Husain
I George
IG
Fantus
D051722:ADAM Proteins / Q000378:metabolism*; D000072198:ADAM17 Protein; D000419:Albuminuria / Q000517:prevention & control; D000818:Animals; D024141:Collagen Type IV / Q000096:biosynthesis*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D003928:Diabetic Nephropathies / Q000517:prevention & control*; D066246:ErbB Receptors / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005947:Glucose / Q000008:administration & dosage; D008297:Male; D050527:Mesangial Cells / Q000378:metabolism; D051379:Mice; D050199:Podocytes / Q000187:drug effects / Q000502:physiology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects; D019061:src-Family Kinases / Q000037:antagonists & inhibitors*
C412373:AG 1879; D024141:Collagen Type IV; D011743:Pyrimidines; D066246:ErbB Receptors; D019061:src-Family Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606463:Adam17 protein, mouse; C000606464:Adam17 protein, rat; D005947:Glucose