p38 MAPK activity is stimulated by vascular endothelial growth factor receptor 2 activation and is essential for shear stress‐induced angiogenesis

Abstract

Increased capillary shear stress induces angiogenesis in skeletal muscle, but the signaling mechanisms underlying this response are not known. We hypothesize that shear stress-dependent activation of vascular endothelial growth factor receptor 2 (VEGFR2) causes p38 and ERK1/2 phosphorylation, which contribute to shear stress-induced angiogenesis. Skeletal muscle microvascular endothelial cells were sheared (12 dynes/cm 2 , 0.5-24 hours). VEGFR2-Y1214 phosphorylation increased in response to elevated shear stress and VEGF stimulation. p38 and ERK1/2 phosphorylation increased at 2 hours of shear stress, but only p38 remained phosphorylated at 6 and 24 hours of shear stress. VEGFR2 inhibition abrogated p38, but not ERK1/2 phosphorylation. VEGF production was increased in response to shear stress at 6 hours, and this increased production was abolished by p38 inhibition. Male Sprague-Dawley rats were administered prazosin (50 mg/L drinking water, 1, 2, 4 or 7 days) to induce chronically elevated capillary shear stress in skeletal muscle. In some experiments, mini-osmotic pumps were used to dispense p38 inhibitor SB203580 or its inactive analog SB202474, to the extensor digitorum longus (EDL) of control and prazosin treated rats. Immunostaining and Western blotting showed increases in p38 phosphorylation in capillaries from rats treated with prazosin for 2 days but returned to basal levels at 4 and 7 days. p38 inhibition abolished the increase in capillary to muscle fibre ratio seen after 7 days of prazosin treatment. Our data suggest that p38 activation is necessary for shear stress-dependent angiogenesis.

14S,21R-Dihydroxydocosahexaenoic Acid Remedies Impaired Healing and Mesenchymal Stem Cell Functions in Diabetic Wounds

“…Activation of p38 and/or ERK1/2 is required for normal angiogenesis (27), including endothelial cell migration and vasculature formation (49,66). p38 and ERK1/2 activation also have important roles in VEGF expression in endothelial cells and MSCs (67,68).…”

“…Cells were lysed for analysis of expression of P-p38 and P-ERK1/2 (phosphorylated forms) as well as p38 and ERK1 (nonphosphorylated forms). Western blot was performed as described previously (27,28) with minor modification. Briefly, 30 g of total proteins from each lysed sample was resolved by SDS-PAGE on 4 -15% Tris-HCl gels (BioRad).…”

“…We demonstrate that 14S,21R-diHDHA restored wound healing and angiogenesis in diabetic mice as well as the pro-healing functions of db/db MSCs and key cellular processes of angiogenesis. It activates the p38 MAPK but does not affect the ERK1/2, although signaling through both p38 MAPK and ERK1/2 is critical for wound healing and associated angiogenesis (27,28).…”

Autacoid 14S,21R-Dihydroxy-Docosahexaenoic Acid Counteracts Diabetic Impairment of Macrophage Prohealing Functions

“…16,34,35 Briefly, The db/db, db/ϩ,12/15-LOX Ϫ/Ϫ and C57BL/6J peritoneal macrophages were analyzed for 12/15-LOX expression. In another experiment, quiescent macrophages were cultured in RPMI 1640 medium containing 5.5 mmol/L glucose (for db/ϩ, 12/15-LOX Ϫ/Ϫ , and C57BL/6J) or 25 mmol/L glucose (for db/db) with or without 14S,21R-diHDHA and/or IL-4 for 24 hours.…”

Le rôle des kinasesMek1etMek2dans la formation de la barrière hématoplacentaire chez la souris

“…L'augmentation d'expression de Vegf corrèle avec une augmentation de l'activation de p38/MAPK [13]. La voie p38/MAPK est impliquée dans la réponse au VEGF lors de l'angiogenèse et elle est fortement activée dans les cellules endothéliales du placenta en formation (Figure 2) [27]. Ces résultats montrent que l'expression du VEGF est dépendante de b-Raf, mais indépendante de l'activation de ERK par MEK1.…”