Article

Increased blood pressure in mice lacking cytochrome P450 2J5

Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA.
The FASEB Journal (Impact Factor: 5.48). 09/2008; 22(12):4096-108. DOI: 10.1096/fj.08-114413
Source: PubMed

ABSTRACT The cytochrome P450 (CYP) enzymes participate in a wide range of biochemical functions, including metabolism of arachidonic acid and steroid hormones. Mouse CYP2J5 is abundant in the kidney where its products, the cis-epoxyeicosatrienoic acids (EETs), modulate sodium transport and vascular tone. To define the physiological role of CYP2J5 in the kidney, knockout mice were generated using a conventional gene targeting approach. Cyp2j5 (-/-) mice develop normally and exhibit no overt renal pathology. While renal EET biosynthesis was apparently unaffected by the absence of CYP2J5, deficiency of this CYP in female mice was associated with increased blood pressure, enhanced proximal tubular transport rates, and exaggerated afferent arteriolar responses to angiotensin II and endothelin I. Interestingly, plasma 17beta-estradiol levels were reduced in female Cyp2j5 (-/-) mice and estrogen replacement restored blood pressure and vascular responsiveness to normal levels. There was no evidence of enhanced estrogen metabolism, or altered expression or activities of steroidogenic enzymes in female Cyp2j5 (-/-) mice, but their plasma levels of luteinizing hormone and follicle stimulating hormone were inappropriately low. Together, our findings illustrate a sex-specific role for CYP2J5 in regulation of blood pressure, proximal tubular transport, and afferent arteriolar responsiveness via an estrogen-dependent mechanism.

Download full-text

Full-text

Available from: Kenneth S Korach, Jul 05, 2015
1 Follower
 · 
110 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The cytochrome P450 epoxygenase, CYP2J2, converts arachidonic acid to four regioisomeric epoxyeicosatrienoic acids (EETs), which are highly abundant in the kidney and considered renoprotective. Accumulating evidence suggests that EETs are important in regulating renal and cardiovascular function. Further, EETs have been confirmed to exert diverse biological activities including potent vasodilation; fibrinolytic properties; and antiinflammatory, antiapoptotic, and mitogenic effects. In the current study, we investigated the effects of overexpression of CYP2J2 via recombinant adeno-associated virus (rAAV) in protection against renal damage in a rat 5/6 nephrectomy (5/6-Nx) model of chronic renal failure. The rAAV-CYP2J2 gene delivery in vivo increased EET generation; attenuated the rise in blood pressure; and reduced the levels of proteinuria, serum creatinine, and blood urea nitrogen. Morphological analysis indicated that rAAV-CYP2J2 gene delivery reduced 5/6 nephrectomy-induced glomerular sclerosis, tubular dilatation, luminal protein cast formation, and tubulointerstitial fibrosis. rAAV-CYP2J2 gene delivery also significantly lowered collagen I and IV deposition, as well as renal cell apoptosis detected by TUNEL staining, caspase-3 activity, and the loss of mitochondrial membrane potential (ΔΨ(m)). Furthermore, rAAV-CYP2J2 gene delivery regulated the level of protein expression including transforming growth factor (TGF)-β(1)/SMADs; matrix metalloproteinases (MMPs); mitogen-activated protein kinases (MAPKs); and apoptosis-related proteins Bax, Bcl-2, and Bcl-x(L). Together, these findings demonstrated that rAAV-CYP2J2 gene delivery can protect remnant kidney against renal injury in 5/6-Nx rats by inhibiting apoptosis and fibrosis via regulation of protein expression including TGF-β(1)/SMADs, MMPs, MAPKs, and apoptosis-related proteins.
    Human gene therapy 01/2012; 23(7):688-99. DOI:10.1089/hum.2011.135 · 3.62 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: There are few in vivo knockout models available to study the function of Cyp2 members involved in the metabolism of endogenous and exogenous chemicals. These models may help provide insight into the cytochrome P450s (CYPs) responsible for the detoxification and activation of drugs, environmental toxicants, and endobiotics. The aim of this work is to produce a potent Cyp2b-knockdown (KD) mouse for subsequent study of Cyp2b function. We made a quintuple Cyp2b-KD mouse using lentiviral-promoted short hairpin RNA (shRNA) homologous to all five murine Cyp2b subfamily members (Cyp2b9, 2b10, 2b13, 2b19, and 2b23). The Cyp2b-KD mice are viable, fertile, and without obvious gross abnormalities except for an increase in liver weight. Expression of the three hepatic Cyp2b members, 2b9, 2b10, and 2b13, is significantly repressed as demonstrated by quantitative real-time PCR and Western blotting. The constitutive androstane receptor activator, 1,4-Bis[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP), was used to determine if shRNA-mediated Cyp2b10 repression could be outcompeted by Cyp2b10 induction. TCPOBOP-treated Cyp2b-KD mice show 80-90% less Cyp2b protein expression than TCPOBOP-treated wild-type (WT) mice, demonstrating that Cyp induction does not outcompete the repressive function of the shRNA. Untreated and TCPOBOP-treated Cyp2b-KD mice are poor metabolizers of parathion compared with WT mice. Furthermore, Cyp2b-KD mice are sensitive to parathion, an organophosphate insecticide primarily metabolized by Cyp2b enzymes, when compared with WT mice. In summary, we designed an shRNA construct that repressed the expression and activity of multiple Cyp2b enzymes. We foresee that this novel Cyp2b-KD mouse model will significantly improve our understanding of the role of Cyp2b enzymes in chemical sensitivity and drug metabolism.
    Toxicological Sciences 11/2011; 125(2):368-81. DOI:10.1093/toxsci/kfr309 · 4.48 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Heme oxygenase (HO) and cytochrome P450 (P450)-derived epoxyeicosatrienoic acids (EETs) participate in vascular protection, and recent studies suggest these two systems are functionally linked. We examined the consequences of HO deficiency on P450-derived EETs with regard to body weight, adiposity, insulin resistance, blood pressure, and vascular function in HO-2-null mice. The HO-2-null mice were obese, displayed insulin resistance, and had high blood pressure. HO-2 deficiency was associated with decreases in cyp2c expression, EET levels, HO-1 expression, and HO activity and with an increase in superoxide production and an impairment in the relaxing response to acetylcholine. In addition, HO-2-null mice exhibited increases in serum levels of tumor necrosis factor (TNF)-alpha and macrophage chemoattractant protein (MCP)-1 and a decrease in serum adiponectin levels. Treatment of HO-2-null mice with a dual-activity EET agonist/soluble epoxide hydrolase inhibitor increased renal and vascular EET levels and HO-1 expression, lowered blood pressure, prevented body weight gain, increased insulin sensitivity, reduced subcutaneous and visceral fat, and decreased serum TNF-alpha and MCP-1, while increasing adiponectin and restoring the relaxing responses to acetylcholine. The decrease in cyp2c expression and EETs levels in HO-2-null mice underscores the importance of the HO system in the regulation of epoxygenase levels and suggests that protection against obesity-induced cardiovascular complications requires interplay between these two systems. A deficiency in one of these protective systems may contribute to the adverse manifestations associated with the clinical progression of the metabolic syndrome.
    Journal of Pharmacology and Experimental Therapeutics 09/2009; 331(3):906-16. DOI:10.1124/jpet.109.157545 · 3.86 Impact Factor