Premium
Smooth Muscle Specific Expression of a Dominant Negative Cullin 3 Mutant (Cul3Δ9) Causes Vascular Dysfunction in Mice Mediated by RhoA/Rho‐kinase
Author(s) -
Agbor Larry N,
Ibeawuchi StellaRita C,
Hu Chunyan,
Quelle Frederick W,
Sigmund Curt D
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.953.6
Subject(s) - rhoa , medicine , endocrinology , vascular smooth muscle , angiotensin ii , biology , rho associated protein kinase , chemistry , microbiology and biotechnology , kinase , signal transduction , smooth muscle , blood pressure
Dominant de novo mutations in Cullin 3 (Cul3) resulting in deletion of exon 9 (Cul3Δ9) cause severe early onset human hypertension mediated in part by impairing the degradation of WNK4 in the kidneys. However, the extra renal mechanisms remain uninvestigated. Previously, we showed that knockout of Cul3 in HEK293T cells induced by clustered regularly interspersed short palindromic repeats (CRISPR)‐Cas9 resulted in accumulation of the Cul3 substrate RhoA. We hypothesized that smooth muscle (SMC) expression of Cul3Δ9 protein in mice impairs endogenous Cul3 wildtype (WT) function and causes vascular dysfunction via elevated RhoA/Rho‐kinase signaling. We generated a novel transgenic mouse model inducibly expressing Cul3Δ9 protein specifically in smooth muscle (termed S‐Cul3Δ9) and assessed vascular responses in the cerebral basilar artery and aorta using a pressurized and a wire myograph respectively. Basilar artery from S‐Cul3Δ9 transgenic mice exhibited significantly impaired relaxation responses to acetylcholine (ACh) (at 100 μmol/L: 15±4% S‐Cul3Δ9 vs 65±5% WT, p<0.0001) and to the nitric oxide donor sodium nitroprusside (SNP) (at 100 μmol/L: 59±2% S‐Cul3Δ9 vs 90±5% WT, p<0.05). Vasoconstriction responses to angiotensin II (Ang II) and to phenylephrine (PE) were significantly elevated in S‐Cul3Δ9 transgenic mice compared to WT. Consistent with data from basilar artery, aorta from S‐Cul3Δ9 transgenic mice exhibited impaired ACh‐mediated relaxation (at 100 μmol/L: 55±2% S‐Cul3Δ9 vs 71±7% WT, p<0.0001). RhoA protein expression was significant elevated in aorta of S‐Cul3Δ9 transgenic mice (1.6±0.2 S‐Cul3Δ9 vs 1.0±0.1 WT, P<0.05). Interestingly, incubation with the Rho‐kinase inhibitor (Y27632) completely restores ACh relaxation responses to WT levels in both the basilar artery and aorta of S‐Cul3Δ9 mice. Taken together, these findings suggest a novel vascular specific mechanism whereby Cul3Δ9 protein interferes with endogenous Cul3 and impairs the degradation of Cul3 substrates such as RhoA, contributing, at least in part, to vascular dysfunction in mice. Support or Funding Information This work was supported by National Institutes of Health Grants HL048058, HL062984, and HL084207 (to C. D. S.).