Jørgen Frøkiær

TY - JOUR

T1 - Increased cyclooxygenase-2 expression and prostaglandin E2 production in pressurized renal medullary interstitial cells

AU - Carlsen, Inge Gram

AU - Donohue, Kaitlin E

AU - Jensen, Anja M

AU - Selzer, Angela L

AU - Chen, Jie

AU - Poppas, Dix P

AU - Felsen, Diane

AU - Frøkiær, Jørgen

AU - Nørregaard, Rikke

PY - 2010

Y1 - 2010

N2 - Renal medullary interstitial cells (RMICs) are subjected to osmotic, inflammatory and mechanical stress as a result of ureteral obstruction, which may influence the expression and activity of cyclooxygenase type 2 (COX-2). Inflammatory stress strongly induces COX-2 in RMIC. To explore the direct effect of mechanical stress on the expression and activity of COX-2, cultured RMIC were subjected to varying amounts of pressure over time using a novel pressure apparatus. COX-2 mRNA and protein were induced following 60 mmHg for 4 and 6h, respectively. COX-1 mRNA and protein levels were unchanged. Prostaglandin E(2) (PGE(2)) production in the RMIC was increased, when cells were subjected to pressure of 60 mm Hg for 6h, and prevented by a selective COX-2 inhibitor. Pharmacological inhibition indicating that pressure-induced COX-2 expression is dependent on p38 mitogen-activated protein kinase (MAPK), and biochemical knockdown experiments showed that NFkappaB might be involved in the COX-2 induction by pressure. Importantly, TUNEL and MTT assay studies showed that subjecting RMIC to 60 mmHg pressure for 6h does not affect cell viability, apoptosis, and proliferation. To further examine the regulation of COX-2 in vivo, rats were subjected to unilateral ureteral obstruction (UUO) for 6 and 12 h. COX-2 mRNA and protein level was increased in inner medulla (IM) in response to 6 and 12h UUO. COX-1 mRNA and protein levels were unchanged. These findings suggest that in vitro application of pressure recapitulates the effects on RMIC found after in vivo UUO. This directly implicates pressure as an important regulator of renal COX-2 expression.

AB - Renal medullary interstitial cells (RMICs) are subjected to osmotic, inflammatory and mechanical stress as a result of ureteral obstruction, which may influence the expression and activity of cyclooxygenase type 2 (COX-2). Inflammatory stress strongly induces COX-2 in RMIC. To explore the direct effect of mechanical stress on the expression and activity of COX-2, cultured RMIC were subjected to varying amounts of pressure over time using a novel pressure apparatus. COX-2 mRNA and protein were induced following 60 mmHg for 4 and 6h, respectively. COX-1 mRNA and protein levels were unchanged. Prostaglandin E(2) (PGE(2)) production in the RMIC was increased, when cells were subjected to pressure of 60 mm Hg for 6h, and prevented by a selective COX-2 inhibitor. Pharmacological inhibition indicating that pressure-induced COX-2 expression is dependent on p38 mitogen-activated protein kinase (MAPK), and biochemical knockdown experiments showed that NFkappaB might be involved in the COX-2 induction by pressure. Importantly, TUNEL and MTT assay studies showed that subjecting RMIC to 60 mmHg pressure for 6h does not affect cell viability, apoptosis, and proliferation. To further examine the regulation of COX-2 in vivo, rats were subjected to unilateral ureteral obstruction (UUO) for 6 and 12 h. COX-2 mRNA and protein level was increased in inner medulla (IM) in response to 6 and 12h UUO. COX-1 mRNA and protein levels were unchanged. These findings suggest that in vitro application of pressure recapitulates the effects on RMIC found after in vivo UUO. This directly implicates pressure as an important regulator of renal COX-2 expression.

U2 - 10.1152/ajpregu.00544.2009

DO - 10.1152/ajpregu.00544.2009

M3 - Journal article

C2 - 20610829

JO - American Journal of Physiology: Regulatory, Integrative and Comparative Physiology

JF - American Journal of Physiology: Regulatory, Integrative and Comparative Physiology

SN - 0363-6119

ER -