RhoBTB1 protects against hypertension and arterial stiffness by restraining phosphodiesterase 5 activity
Masashi Mukohda, … , Frederick W. Quelle, Curt D. Sigmund
Masashi Mukohda, … , Frederick W. Quelle, Curt D. Sigmund
Published March 21, 2019
Citation Information: J Clin Invest. 2019;129(6):2318-2332. https://doi.org/10.1172/JCI123462.
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Research Article Vascular biology

RhoBTB1 protects against hypertension and arterial stiffness by restraining phosphodiesterase 5 activity

Abstract

Mice selectively expressing a PPARγ dominant-negative mutation in vascular smooth muscle exhibit RhoBTB1 deficiency and hypertension. Our rationale was to use genetic complementation to uncover the mechanism of action of RhoBTB1 in vascular smooth muscle. Inducible smooth muscle–specific restoration of RhoBTB1 fully corrected hypertension and arterial stiffness by improving vasodilator function. Notably, the cardiovascular protection occurred despite the preservation of increased agonist-mediated contraction and RhoA and Rho kinase activity, suggesting that RhoBTB1 selectively controls vasodilation. RhoBTB1 augmented the cyclic 3′,5′-monophosphate (cGMP) response to NO by restraining the activity of phosphodiesterase 5 (PDE5) through its action as a substrate adaptor delivering PDE5 to the Cullin-3 E3 ring ubiquitin ligase complex for ubiquitination, thereby inhibiting PDE5. Angiotensin II infusion also caused RhoBTB1 deficiency and hypertension, which were prevented by smooth muscle–specific RhoBTB1 restoration. We conclude that RhoBTB1 protected against hypertension, vascular smooth muscle dysfunction, and arterial stiffness in at least 2 models of hypertension.

Authors

Masashi Mukohda, Shi Fang, Jing Wu, Larry N. Agbor, Anand R. Nair, Stella-Rita C. Ibeawuchi, Chunyan Hu, Xuebo Liu, Ko-Ting Lu, Deng-Fu Guo, Deborah R. Davis, Henry L. Keen, Frederick W. Quelle, Curt D. Sigmund

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Figure 4

Analysis of the cGMP pathway.

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Analysis of the cGMP pathway. (A) Schematic diagram of the NO vasodilati...
(A) Schematic diagram of the NO vasodilation pathway. (B) Aortae from control, S-P467L, or S-P467L/S-RhoBTB1 mice 3–4 weeks after completion of Tx treatment were treated with or without l-NAME (100 μM, 30 min), followed by isometric tension experiments with ACh. n = 4–6 samples. (C and D) Isometric tension experiments were performed with NS1619 (n = 4–5) (C), or BAY41-2272 (n = 6–8) (D). (E) Production of cGMP in aortae from Tx-treated control, S-P467L, or S-P467L/S-RhoBTB1 mice. Vessel samples were incubated with or without SNP for 20 minutes, and cGMP levels were measured. (F) Western blot of total aortic protein was probed with antisera for the indicated proteins. Shown are 2 representative blots from 4 samples assayed for each genotype. Size markers transferred from the blots are shown. (G and H) Isometric tension experiments were performed with 8-Br-cGMP (n = 7) (G) or 8-pCPT-cGMP (n = 4) (H) in aortae from control, S-P467L, or S-P467L/S-RhoBTB1 mice 3–4 weeks after Tx treatment. (I) Comparison of vasodilation response to 8-Br-cGMP and 8-pCPT-cGMP. (J) PDE activity in aortae from Tx-treated control, S-P467L, or S-P467L/S-RhoBTB1 mice. All data represent the mean ± SEM. *P < 0.05 versus control; #P < 0.05, S-P467L versus S-P467L/S-RhoBTB1 mice; 1-way ANOVA or 2-way repeated-measures ANOVA.