scholarly journals Dominant negative PPARγ promotes atherosclerosis, vascular dysfunction, and hypertension through distinct effects in endothelium and vascular muscle

2013 ◽  
Vol 304 (9) ◽  
pp. R690-R701 ◽  
Author(s):  
Christopher J. Pelham ◽  
Henry L. Keen ◽  
Steven R. Lentz ◽  
Curt D. Sigmund

Agonists of the nuclear hormone receptor peroxisome proliferator-activated receptor γ (PPARγ) have potent insulin-sensitizing effects and inhibit atherosclerosis progression in patients with Type II diabetes. Conversely, missense mutations in the ligand-binding domain of PPARγ that render the transcription factor dominant negative (DN) cause early-onset hypertension and Type II diabetes. We tested the hypothesis that DN PPARγ-mediated interference of endogenous wild-type PPARγ in the endothelium and vascular smooth muscle exacerbates atherosclerosis in apolipoprotein E-deficient (ApoE−/−) mice. Endothelium-specific expression of DN PPARγ on the ApoE−/− background unmasked significant impairment of endothelium-dependent relaxation in aortic rings, increased systolic blood pressure, altered expression of atherogenic markers (e.g., Cd36, Mcp1, Catalase), and enhanced diet-induced atherosclerotic lesion formation in aorta. Smooth muscle-specific expression of DN PPARγ, which induces aortic dysfunction and increased systolic blood pressure at baseline, also resulted in enhanced diet-induced atherosclerotic lesion formation in aorta on the ApoE−/− background that was associated with altered expression of a shared, yet distinct, set of atherogenic markers (e.g., Cd36, Mcp1, Osteopontin, Vcam1). In particular, induction of Osteopontin expression by smooth muscle-specific DN PPARγ correlated with increased plaque calcification. These data demonstrate that inhibition of PPARγ function specifically in the vascular endothelium or smooth muscle may contribute to cardiovascular disease.

2016 ◽  
Vol 112 (2) ◽  
pp. 606-616 ◽  
Author(s):  
Mu-En Lin ◽  
Theodore M. Chen ◽  
Mary C. Wallingford ◽  
Ngoc B. Nguyen ◽  
Shunsuke Yamada ◽  
...  

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Morgan Salmon ◽  
Anna Z Fashandi ◽  
Michael D Spinosa ◽  
Ashish K Sharma ◽  
Gary K Owens ◽  
...  

Objective: Zinc-finger protein 148 (ZFP148) plays a profound role in the modulation of aortic aneurysm formation in part via modulation of smooth muscle (SMC) genes. The current study objective was to determine whether smooth muscle specific knock-out of ZFP148 is critical in atherosclerotic lesion formation. Methods: ZFP148 was examined via immunohistochemistry and confocal microscopy in human atherosclerotic lesion samples (n=12/group). 6-8 week male (n=12/group) ZFP flx/flx Myh11 Cre+ ApoE-/-(SMC tamoxifen ZFP148 KO), Myh11 ZFP148 flx/wt Cre+ ApoE-/- and Myh11 ZFP wt/wt Cre+ ApoE-/- underwent tamoxifen injections followed by western diet feeding for either 13 or 25 weeks. A separate set of mice were fed western diet for 18 weeks and then administered tamoxifen injections. Aortic samples were evaluated with histology for α-actin, macrophages, neutrophils, TER119, caspase3, Ki67, picosirus red and movat staining. In vitro ZFP148 was knocked down using siRNA in smooth muscle cells and stimulated with the oxidized phospholipid POVPC. Results: ZFP148 expression was elevated in human atherosclerotic lesion samples and localized to smooth muscle cells. Lesion size was significantly reduced in SMC ZFP148 KO mice compared with controls in 25 week western diet fed mice(p<0.0357). SMC ZFP148 KO demonstrated reduced macrophage, Caspase3, and TER119 staining. Conversely, SMC ZFP148 KO increased SMα-actin coverage. Lesion size was also decreased in mice that were administered tamoxifen injections following 18 weeks of western diet feeding(p<0.0415). There were no significant changes in lesion size at 13 weeks of western diet feeding; however, macrophage staining was decreased. Knock-down of ZFP148 followed by treatment with POVPC attenuated the down-regulation of SM22α, SM-MHC, and SMαA. Knock-down of ZFP148 followed by POVPC treatment also prevented the up-regulation of Bax and BAD in vascular smooth muscle cells. Conclusions: While earlier studies documented a role for ZFP148 in aneurysm disease, the present study suggests that SMC ZFP148 KO attenuates atherosclerotic lesion formation in early and late atherosclerotic disease. ZFP148 represents a key regulator of multiple types of vascular disease.


10.1038/nm876 ◽  
2003 ◽  
Vol 9 (6) ◽  
pp. 736-743 ◽  
Author(s):  
Christoph J Binder ◽  
Sohvi Hörkkö ◽  
Asheesh Dewan ◽  
Mi-Kyung Chang ◽  
Emily P Kieu ◽  
...  

2001 ◽  
Vol 88 (5) ◽  
pp. 506-512 ◽  
Author(s):  
Kazunobu Ishikawa ◽  
Daisuke Sugawara ◽  
Xu-ping Wang ◽  
Kazunori Suzuki ◽  
Hiroyuki Itabe ◽  
...  

FEBS Letters ◽  
1999 ◽  
Vol 459 (2) ◽  
pp. 218-222 ◽  
Author(s):  
Durairaj Ponraj ◽  
Jagoda Makjanic ◽  
Patricia S.P Thong ◽  
Benny K.H Tan ◽  
Frank Watt

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Christian Kuété Fofié ◽  
Elvine Pami Nguelefack-Mbuyo ◽  
Nole Tsabang ◽  
Albert Kamanyi ◽  
Télesphore Benoît Nguelefack

Parts of Ceiba pentandra are wildly used in Africa to treat diabetes and previous works have demonstrated their in vivo antidiabetic effects on type 1 diabetes models. In addition, it has been recently shown that the decoction and the methanol extract from the stem bark of C. pentandra potentiate in vitro, the peripheral glucose consumption by the liver and skeletal muscle slices. But nothing is known about its effect on type II diabetes, especially on insulin resistance condition. We investigated herein the antihyperglycemic, insulin-sensitizing potential, and cardioprotective effects of the dried decoction from the stem bark of Ceiba pentandra (DCP) in dexamethasone-induced insulin resistant rats. DCP phytochemical analysis using LC-MS showed the presence of many compounds, including 8-formyl-7-hydroxy-5-isopropyl-2-methoxy-3-methyl-1,4-naphthaquinone, 2,4,6-trimethoxyphenol, and vavain. Wistar rats were given intramuscularly (i.m.) dexamethasone (1 mg/kg/day) alone or concomitantly with oral doses of DCP (75 or 150 mg/kg/day) or metformin (40 mg/kg/day) for 9 days. Parameters such as body weight, glycemia, oral glucose tolerance, plasma triglycerides and cholesterol, blood pressure, and heart rate were evaluated. Moreover, cardiac, hepatic and aortic antioxidants (reduced glutathione, catalase, and superoxide dismutase), malondialdehyde level, and nitric oxide content were determined. DCP decreased glycemia by up to 34% and corrected the impairment of glucose tolerance induced by dexamethasone but has no significant effect on blood pressure and heart rate. DCP reduced the total plasma cholesterol and triglycerides as compared to animals treated only with dexamethasone. DCP also increased catalase, glutathione, and NO levels impaired by dexamethasone, without any effect on SOD and malondialdehyde. In conclusion, the decoction of the stem bark of Ceiba pentandra has insulin sensitive effects as demonstrated by the improvement of glucose tolerance, oxidative status, and plasma lipid profile. This extract may therefore be a good candidate for the treatment of type II diabetes.


2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Sarah Srodulski ◽  
Victoria L King

Microsomal prostaglandin E 2 synthase-1 (mPGES-1) catalyzes the conversion of COX-2 generated PGH 2 to PGE 2 and is the predominate source of PGE 2 during and inflammatory response. We and others have demonstrated that mPGES-1 deficiency attenuates atherosclerosis in mice on a mixed background. The present study investigated the effect of mPGES-1 deficiency on atherosclerosis in C57BL/6 low density lipoprotein receptor deficient (LDLr-/-) mice. mPGES-1 deficiency attenuated atherosclerosis in LDLr-/- mice fed either a low fat (LF) (P = 0.02) or high fat (HF) (P = 0.0026) diet enriched with cholesterol, or a western diet (P = 0.02) for 17 weeks. mPGES-1 deficiency attenuated weight gain and cholesterol concentrations in mice fed a western (P = 0.004 and P < 0.05; respectively) or HF diet (P = 0.01 and P = 0.012, respectively). However, body weight and cholesterol concentrations were not different in mice fed the LF diet. These data suggest that different mechanisms mediate the reduction in atherosclerosis in mPGES-1 deficient mice fed LF and HF diets. To determine if mPGES-1 deficiency in macrophages contributed to the reduction in atherosclerosis in mice fed HF diets, 4 groups of chimeric mice were generated. Four weeks post bone marrow cell transplant (BMT) mice were fed a western diet. BMT attenuated weight gain in all groups of chimeric mice; however, weight gain was not different between any of the groups. BMT decreased atherosclerotic lesion formation 10 fold in all groups of mice. Neither bone marrow cell specific deficiency of mPGES-1 (KO>WT) or mPGES-1 specific expression in bone marrow derived cells (WT>KO) had an effect on lesion formation compared to WT>WT or KO>KO mice. Cholesterol concentrations were decreased in KO>KO and WT>KO mice compared to WT>WT (P < 0.01) and KO>WT (P< 0.05) mice. These data suggest that mPGES-1 expression in bone marrow derived cells does not contribute to the development of atherosclerosis. Moreover, these data suggest that prostanoids may play a role in hepatic cholesterol homeostasis in mice fed HF diets enriched in cholesterol thereby contributing to atherosclerotic lesion formation. Moreover, these data provide further evidence that prostanoids play a role in regulating the accumulation of diet-induced adiposity.


Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Pimonrat Ketsawatsomkron ◽  
Deborah R Davis ◽  
Aline M Hilzendeger ◽  
Justin L Grobe ◽  
Curt D Sigmund

PPARG, a ligand-activated transcription factor plays a critical role in the regulation of blood pressure and vascular function. We hypothesized that smooth muscle cell (SMC) PPARG protects against hypertension (HT) and resistance vessel dysfunction. Transgenic mice expressing dominant negative PPARG (S-P467L) in SMC or non-transgenic controls (NT) were implanted with DOCA pellet and allowed ad libitum access to 0.15 M NaCl for 21 days in addition to regular chow and water. Blood pressure was monitored by telemetry and mesenteric arterial (MA) function was assessed by pressurized myograph. At baseline, 24-hour mean arterial pressure (MAP) was similar between NT and S-P467L mice, while the transgenic mice were tachycardic. DOCA-salt increased MAP to a much greater degree in S-P467L mice (Δ MAP; S-P467L: +34.2±6.0, NT: +13.3±5.7, p<0.05 vs NT). Heart rate was similarly decreased in both groups after DOCA-salt. Vasoconstriction to KCl, phenylephrine and endothelin-1 did not differ in MA from DOCA-salt treated NT and S-P467L, while the response to vasopressin was significantly reduced in S-P467L after DOCA-salt (% constriction at 10-8 M, S-P467L: 31.6±5.6, NT: 46.7±3.8, p<0.05 vs NT). Urinary copeptin, a surrogate marker for arginine vasopressin was similar in both groups regardless of treatment. Vasorelaxation to acetylcholine was slightly impaired in S-P467L MA compared to NT at baseline whereas this effect was further exaggerated after DOCA-salt (% relaxation at 10-5 M, S-P467L: 56.1±8.3, NT: 79.4±5.6, p<0.05 vs NT). Vascular morphology at luminal pressure of 75 mmHg showed a significant increase in wall thickness (S-P467L: 18.7±0.8, NT: 16.0±0.4, p<0.05 vs NT) and % media/lumen (S-P467L: 8.4±0.3, NT: 7.1±0.2, p<0.05 vs NT) in S-P467L MA after DOCA-salt. Expression of tissue inhibitor of metalloproteinases (TIMP)-4 and regulator of G-protein signaling (RGS)-5 transcript were 2- and 3.5-fold increased, respectively, in MA of NT with DOCA-salt compared to NT baseline. However, this induction was markedly blunted in S-P467L MA. We conclude that interference with PPARG function in SMC leads to altered gene expression crucial for normal vascular homeostasis, thereby sensitizing the mice to the effects of DOCA-salt induced HT and vascular dysfunction.


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