Angiotensin II blockade prevents hyperglycemia-induced activation of JAK and STAT proteins in diabetic rat kidney glomeruli

Amy K. Banes, Séan Shaw, John Jenkins, Heather Redd, Farhad Amiri, David M. Pollock, Mario B. Marrero

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Abstract

Clinical and animal studies show that treatment with angiotensin-converting enzyme (ACE) inhibitors or ANG II-receptor antagonists slows progression of nephropathy in diabetes, indicating ANG II plays an important role in its development. We previously reported that hyperglycemia augments both ANG II-induced growth and activation of Janus kinase (JAK)2 and signal transducers and activators of transcription (STAT) proteins in cultured rat mesangial cells. Furthermore, we demonstrated that the tyrosine kinase enzyme JAK2 plays a key role in both ANG II- and hyperglycemia-induced growth in these cells. We hypothesized that the ACE inhibitor captopril and the ANG II-receptor antagonist candesartan would hinder hyperglycemic-induced activation of JAK and STAT proteins in rat glomeruli, demonstrating that ANG II plays an important role in the activation of these proteins in vivo. Adult male Sprague-Dawley rats were given either streptozotocin (STZ; 60 mg/kg iv) or vehicle, and glomeruli were isolated 2 wk later. Activation of JAK and STAT proteins was evaluated by Western blot analysis for specific tyrosine phosphorylation. Groups of rats were given captopril (75-85 mg·kg -1·day-1), candesartan (10 mg· kg -1·day-1), or the JAK2 inhibitor AG-490 (5 mg·kg-1·day-1) for the study's duration. STZ stimulated glomerular phosphorylation of JAK2, STAT1, STAT3, and STAT5. Phosphorylation was reduced in rats treated with captopril, candesartan, and AG-490. Furthermore, both candesartan and AG-490 inhibited STZ-induced increases in urinary protein excretion. In conclusion, our studies demonstrate that hyperglycemia induces activation of JAK2 and the STATs in vivo via an ANG II-dependent mechanism and that these proteins may be involved in the early kidney damage associated with diabetes.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Renal Physiology
Volume286
Issue number4 55-4
StatePublished - Apr 1 2004

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Kidney Glomerulus
STAT Transcription Factors
Janus Kinases
Angiotensin II
Hyperglycemia
Captopril
Phosphorylation
Angiotensin-Converting Enzyme Inhibitors
Janus Kinase 2
Proteins
Mesangial Cells
Streptozocin
Growth
Protein-Tyrosine Kinases
Sprague Dawley Rats
Tyrosine
Western Blotting
Kidney
candesartan
Enzymes

Keywords

  • Glomerular mesangial cells
  • Janus kinase/signal transducers and activators of transcription pathway

ASJC Scopus subject areas

  • Physiology

Cite this

Banes, A. K., Shaw, S., Jenkins, J., Redd, H., Amiri, F., Pollock, D. M., & Marrero, M. B. (2004). Angiotensin II blockade prevents hyperglycemia-induced activation of JAK and STAT proteins in diabetic rat kidney glomeruli. American Journal of Physiology - Renal Physiology, 286(4 55-4).

Angiotensin II blockade prevents hyperglycemia-induced activation of JAK and STAT proteins in diabetic rat kidney glomeruli. / Banes, Amy K.; Shaw, Séan; Jenkins, John; Redd, Heather; Amiri, Farhad; Pollock, David M.; Marrero, Mario B.

In: American Journal of Physiology - Renal Physiology, Vol. 286, No. 4 55-4, 01.04.2004.

Research output: Contribution to journalArticle

Banes, Amy K. ; Shaw, Séan ; Jenkins, John ; Redd, Heather ; Amiri, Farhad ; Pollock, David M. ; Marrero, Mario B. / Angiotensin II blockade prevents hyperglycemia-induced activation of JAK and STAT proteins in diabetic rat kidney glomeruli. In: American Journal of Physiology - Renal Physiology. 2004 ; Vol. 286, No. 4 55-4.
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