P38 MAPK inhibitors suppress biomarkers of hypertension end-organ damage, osteopontin and plasminogen activator inhibitor-1.
The assessment of target organ damage is important in defining the optimal treatment of hypertension and blood pressure-related cardiovascular disease. The aims of the present study were (1) to investigate candidate biomarkers of target organ damage, osteopontin (OPN) and plasminogen activator inhibitor-1 (PAI-1), in models of malignant hypertension with well characterized end-organ pathology; and (2) to evaluate the effects of chronic treatment with a p38 MAPK inhibitor. Gene expression, plasma concentrations, and renal immunohistochemical localization of OPN and PAI-1 were measured in stroke-prone spontaneously hypertensive rats on a salt-fat diet (SFD SHR-SP) and in spontaneously hypertensive rats receiving N(omega)-nitro-L-arginine methyl ester (L-NAME SHR). Plasma concentrations of OPN and PAI-1 increased significantly in SFD SHR-SP and L-NAME SHR as compared with controls, (2.5-4.5-fold for OPN and 2.0-9.0-fold for PAI-1). The plasma levels of OPN and PAI-1 were significantly correlated with the urinary excretion of albumin (p < 0.0001). Elevations in urinary albumin, plasma OPN and PAI-1 were abolished by chronic treatment (4-8 weeks) with a specific p38 MAPK inhibitor, SB-239063AN. OPN immunoreactivity was localized predominantly in the apical portion of tubule epithelium, while PAI-1 immunoreactivity was robust in glomeruli, tubules and renal artery endothelium. Treatment with the p38 MAPK inhibitor significantly reduced OPN and PAI-1 protein expression in target organs. Kidney gene expression was increased for OPN (4.9- and 7.9-fold) and PAI-1 (2.8- and 11.5-fold) in SFD SHR-SP and L-NAME SHR, respectively. In-silico pathway analysis revealed that activation of p38 MAPK was linked to OPN and PAI-1 via SPI, c-fos and c-jun; suggesting that these pathways may play an important role in p38 MAPK-dependent hypertensive renal dysfunction. The results suggest that enhanced OPN and PAI-1 expression reflects end-organ damage in hypertension and that suppression correlates with end-organ protection regardless of overt antihypertensive action.
Nerurkar
S S
SS
Department of Investigative and Cardiac Biology, GlaxoSmithKline, King of Prussia, PA 119406, USA.
Olzinski
A R
AR
Frazier
K S
KS
Mirabile
R C
RC
O'Brien
S P
SP
Jing
J
J
Rajagopalan
D
D
Yue
T L
TL
Willette
R N
RN
D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006973:Hypertension / Q000378:metabolism* / Q000503:physiopathology; D007150:Immunohistochemistry; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D053495:Osteopontin / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*
D015415:Biomarkers; D017395:Plasminogen Activator Inhibitor 1; D047428:Protein Kinase Inhibitors; D053495:Osteopontin; D048051:p38 Mitogen-Activated Protein Kinases