Skip to Content
Merck
CN
  • ASK1/p38 signaling in renal tubular epithelial cells promotes renal fibrosis in the mouse obstructed kidney.

ASK1/p38 signaling in renal tubular epithelial cells promotes renal fibrosis in the mouse obstructed kidney.

American journal of physiology. Renal physiology (2014-10-10)
Frank Y Ma, Greg H Tesch, David J Nikolic-Paterson
ABSTRACT

Stress-activated kinases p38 MAPK and JNK promote renal fibrosis; however, how the pathways by which these kinases are activated in kidney disease remain poorly defined. Apoptosis signal-regulating kinase 1 (ASK1/MAPKKK5) is a member of the MAPKKK family that can induce activation of p38 and JNK. The present study examined whether ASK1 induces p38/JNK activation and renal fibrosis in unilateral ureteric obstruction (UUO) using wild-type (WT) and Ask1-deficient (Ask1(-/-)) mice. Basal p38 and JNK activation in WT kidneys was increased three- to fivefold in day 7 UUO mice in association with renal fibrosis. In contrast, there was no increase in p38 activation in Ask1(-/-) UUO mice, whereas JNK activation was only partially increased. The progressive increase in kidney collagen (hydroxyproline) content seen on days 7 and 12 of UUO in WT mice was significantly reduced in Ask1(-/-) UUO mice in association with reduced α-smooth muscle actin-positive myofibroblast accumulation. However, cultured WT and Ask1(-/-) renal fibroblasts showed equivalent proliferation and matrix production, indicating that ASK1 acts indirectly on fibroblasts. Tubular epithelial cells are the main site of p38 activation in the obstructed kidney. Angiotensin II and H₂O₂, but not IL-1 or lipopolysaccharide, induced p38 activation and upregulation of transforming growth factor-β₁, platelet-derived growth factor-B, and monocyte chemoattractant protein-1 production was suppressed in Ask1(-/-) tubular epithelial cells. In addition, macrophage accumulation was significantly inhibited in Ask1(-/-) UUO mice. In conclusion, ASK1 is an important upstream activator of p38 and JNK signaling in the obstructed kidney, and ASK1 is a potential therapeutic target in renal fibrosis.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Selenium, pellets, <5 mm, ≥99.99% trace metals basis
Sigma-Aldrich
Selenium, powder, −100 mesh, ≥99.5% trace metals basis
Millipore
Hydrogen peroxide solution, 3%, suitable for microbiology
Sigma-Aldrich
Urea solution, BioUltra, ~8 M in H2O
Sigma-Aldrich
Hydrogen peroxide solution, 34.5-36.5%
Sigma-Aldrich
Urea-12C, 99.9 atom % 12C
Sigma-Aldrich
Selenium, pellets, <5 mm particle size, ≥99.999% trace metals basis
Sigma-Aldrich
Selenium, powder, −100 mesh, 99.99% trace metals basis
Sigma-Aldrich
Phenylmethanesulfonyl fluoride, ≥99.0% (T)
Sigma-Aldrich
Urea solution, 40 % (w/v) in H2O
Sigma-Aldrich
Sodium pyrophosphate tetrabasic, ≥95%
Sigma-Aldrich
Phenylmethanesulfonyl fluoride, ≥98.5% (GC)
Supelco
4-tert-Octylphenol monoethoxylate solution, 10 μg/mL in acetone, analytical standard
Selenium, foil, 25x25mm, thickness 3mm, 99.95%
Sigma-Aldrich
Hydrogen peroxide solution, contains ~200 ppm acetanilide as stabilizer, 3 wt. % in H2O
Millipore
Urea solution, suitable for microbiology, 40% in H2O
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 35 wt. % in H2O
Sigma-Aldrich
Sodium fluoride 0.5 M solution
Supelco
Urea, 8 M (after reconstitution with 16 mL high purity water)
Sigma-Aldrich
Ethylenediaminetetraacetic acid disodium salt solution, BioUltra, pH 8.0, ~0.5 M in H2O
Supelco
Fluoride ion solution for ISE, 0.1 M F-, for ion-selective electrodes
Sigma-Aldrich
Urea, puriss. p.a., ACS reagent, reag. Ph. Eur., ≥99%
Sigma-Aldrich
Ethylenediaminetetraacetic acid, BioUltra, ≥99.0% (KT)
Sigma-Aldrich
Ethylenediaminetetraacetic acid, ≥98.0% (KT)
Sigma-Aldrich
Sodium fluoride, anhydrous, powder, 99.99% trace metals basis
Sigma-Aldrich
Ethylenediaminetetraacetic acid, 99.995% trace metals basis
Sigma-Aldrich
Sodium fluoride, 99.99% trace metals basis
Sigma-Aldrich
Urea, puriss., meets analytical specification of Ph. Eur., BP, USP, 99.0-100.5%, 99.0-101.0% (calc. on dry substance)
Sigma-Aldrich
Sodium fluoride, BioReagent, suitable for insect cell culture, ≥99%
Sigma-Aldrich
Ethylenediaminetetraacetic acid solution, 0.02% in DPBS (0.5 mM), sterile-filtered, BioReagent, suitable for cell culture