Stimulation of Epithelial Sodium Channels in Endothelial Cells by Bone Morphogenetic Protein-4 Contributes to Salt-Sensitive Hypertension in Rats

Figure 6

BMP4 stimulates ENaC by activating p38 MAPK and Sgk1/Nedd4-2. The experiments were conducted in the primary cultured endothelial cells (ECs) isolated from SS rats and the ECs were, respectively, transfected by p38 MAPK control LV () and p38 MAPK shRNA LV () to knockdown p38 MAPK. (a, b) Representative Western blots and summarized data showing p38 MAPK and p-p38 MAPK protein levels in primary cultured endothelial cells isolated from SS rats either under control conditions or treated with p38 MAPK control LV or p38 MAPK shRNA LV. vs. control ( for each group). (c) Summarized data showing p38 MAPK mRNA levels in primary cultured endothelial cells isolated from SS rats either under control conditions or treated with p38 MAPK control LV or p38 MAPK shRNA LV. vs. control ( for each group). (d–i) Representative Western blots and summarized data showing p38 MAPK, p-p38 MAPK, Sgk1, p-Sgk1, Nedd4-2, and p-Nedd4-2 protein levels in ECs or in p38 MAPK gene manipulated ECs under control conditions or treated with 20 ng/mL BMP4 for 24 hours. indicates vs. control; ^#represents vs. BMP4 ( for each group). (j) Representative ENaC single-channel currents recorded from ECs or in p38 MAPK gene manipulated ECs, in the absence of or in the presence of 20 ng/mL BMP4 (24 hours). (k) Summary of ENaC P_O obtained from the experiments shown in (j). indicates vs. control; ^#represents vs. BMP4 ( for each individual cells).

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

(j)

(k)