Abstract 372: Upregulation of the Mineralocorticoid System in Obesity-associated Diabetes Leads to Increased Adipocyte Rho Kinase Activation and Dysregulation of Adipocytokines

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Aurelie Nguyen Dinh Cat ◽  
Glaucia E Callera ◽  
Tayze T Antunes ◽  
Augusto C Montezano ◽  
Ying He ◽  
...  

Increased activation of the renin-angiotensin-aldosterone (RAAS) system is often associated with obesity and metabolic syndrome. We previously reported that aldosterone (aldo) produced by adipocytes regulate vascular function. Despite the fact that aldo production by adipocytes is increased in obesity, the role of aldo and its receptor, the mineralocorticoid receptor (MR), in the regulation of adipocytes biology and their downstream signaling remain elusive. Since Rho kinase (Rock) signaling has recently been implicated in the development of obesity, we tested the hypothesis that MR upregulation leads to dysregulation of adipokines through Rock-dependent mechanisms in obesity. Here we used obese db/db and lean db/+ mice, treated for 4 weeks with K canrenoate (MR antagonist, 30 mg/kg/day) and fasudil (Rock inhibitor, 30 mg/kg/day). Aldo production and Rock activation were measured by ELISA. mRNA and protein levels of adipokines and Rock signaling were assayed by real time PCR and immunoblotting. Plasma and adipocyte-derived aldo levels were increased in db/db mice (plasma: pg/mL, db/+ 310±33, db/db 567±43, p<0.05; adipocytes: pg/mL/μgRNA, db/+ 329±130, db/db 3125±494, p<0.002), an effect partially prevented by MR blockade (pg/mL/μgRNA: db/db 1278±176, p<0.01) and not by fasudil. Aldosterone synthase mRNA levels were increased (2.3 fold) as well as Nr3c2 (MR) (1.8 fold) and markers of MR activation ( Sgk1 and Ngal - 2.3 and 2.9 fold) in mature adipocytes from db/db mice. In mature adipocytes from db/db, adiponectin mRNA levels were decreased (2.6 fold; p<0.01), whereas leptin and IL-6 mRNA levels were increased (2 and 4.8 fold; p<0.01). All changes were blocked by K canrenoate. Rock activity and downstream effectors, such as activation of MYPT1 and ERM, were increased in perivascular adipose tissue from db/db mice, an effect prevented by MR blockade. In conclusion, our data demonstrate that in db/db mice adipocyte MR-dependent activation of Rock is associated with a pro-inflammatory adipose phenotype that is normalized by MR blockade. Our results implicate a potential role of adipocyte aldo/MR through RhoA/Rock in adipocyte dysfunction in obesity/diabetes, important co-morbidities often associated with metabolic syndrome and hypertension.

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Francesca Schinzari ◽  
Manfredi Tesauro ◽  
Valentina Rovella ◽  
Augusto Veneziani ◽  
Nadia Mores ◽  
...  

Impaired insulin-mediated vasodilation in the skeletal muscle may be involved in the development of hypertension in patients with metabolic syndrome (MetS) and contribute to insulin resistance by diminishing the glucose uptake. Rho-kinase, an effector of the small G protein Rho A, plays an important role in hypertension and is reported to interfere with insulin signaling through serine phosphorylation of insulin receptor substrate-1 in blood vessels. We therefore examined the role of Rho-kinase in the pathophysiology of impaired vascular reactivity in patients with MetS by evaluating the effect of Rho-kinase inhibition on NO-dependent vasodilation during hyperinsulinemia. Forearm blood flow (FBF) responses to acetylcholine (ACh), a stimulus for endothelial release of NO, and sodium nitroprusside (SNP), an exogenous NO donor, were assessed during insulin administration (0.1 mU/Kg/min) using the forearm perfusion technique in patients with MetS (n=10) and matched controls (n=10). Patients with MetS were then randomized to intra-arterial infusion of either fasudil (inhibitor of Rho-kinase, 200 μg/min) or placebo and reactivity to ACh and SNP was reassessed. During hyperinsulinemia, vasodilator responses to both ACh and SNP were blunted in patients with MetS (both P>0.001 vs. controls). In patients who received fasudil, its administration did not change unstimulated FBF (P=0.75 vs. insulin alone); the vasodilator response to ACh, however, was significantly enhanced by fasudil (P=0.009 vs. insulin alone), while the response to SNP was not significantly changed (P=0.56). In patients with MetS who received placebo, vascular reactivity to both ACh and SNP was not different than before (both P>0.05). In conclusion, Rho-kinase inhibition during hyperinsulinemia improves endothelium-dependent vasodilator responsiveness in patients with MetS. This suggests that, under those conditions, intravascular activation of Rho-kinase is involved in the pathophysiology of endothelial dysfunction and may constitute a critical mediator linking metabolic and hemodynamic abnormalities in insulin resistance. As a consequence, targeting Rho-kinase might beneficially impact both vascular function and insulin sensitivity in patients with MetS.


2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Yolanda Mendizábal ◽  
Silvia Llorens ◽  
Eduardo Nava

Metabolic syndrome is a cluster of metabolic and cardiovascular symptoms: insulin resistance (IR), obesity, dyslipemia. Hypertension and vascular disorders are central to this syndrome. After a brief historical review, we discuss the role of sympathetic tone. Subsequently, we examine the link between endothelial dysfunction and IR. NO is involved in the insulin-elicited capillary vasodilatation. The insulin-signaling pathways causing NO release are different to the classical. There is a vasodilatory pathway with activation of NO synthase through Akt, and a vasoconstrictor pathway that involves the release of endothelin-1 via MAPK. IR is associated with an imbalance between both pathways in favour of the vasoconstrictor one. We also consider the link between hypertension and IR: the insulin hypothesis of hypertension. Next we discuss the importance of perivascular adipose tissue and the role of adipokines that possess vasoactive properties. Finally, animal models used in the study of vascular function of metabolic syndrome are reviewed. In particular, the Zucker fatty rat and the spontaneously hypertensive obese rat (SHROB). This one suffers macro- and microvascular malfunction due to a failure in the NO system and an abnormally high release of vasoconstrictor prostaglandins, all this alleviated with glitazones used for metabolic syndrome therapy.


2012 ◽  
Vol 59 (2) ◽  
Author(s):  
Chuan-Bao Li ◽  
Xiao-Xing Li ◽  
Yu-Guo Chen ◽  
Hai-Qing Gao ◽  
Cheng-Mei Bao ◽  
...  

Insulin resistance (IR) plays a critical role in metabolic syndrome (MS). Previous studies have demonstrated that activated ROCK is increased in MS patients. However, the effect of Rho-kinase (ROCK) on IR has not been definitely determined. Thus, the aims of the present study were to determine whether ROCK activation induces IR or affects myocardial structure and function, as well as the possible mechanisms underlying this process. Wistar rats fed high fat, high glucose and high salt diet sewed as model of MS and we used transmission electron microscopy, echocardiogram technology, and terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling staining to identify any myocardial damage. The protein levels of MYPT-1 (characteristic of ROCK activation), IRS-1 and AKT were analyzed by immunohistochemistry and Western blotting. In hearts from MS rats, we found increased protein levels of phospho-MYPT-1 and phospho-IRS-1 (Ser307) and decreased phospho-AKT compared to levels in normal rats. In conclusion, the results suggest that ROCK-mediated IR is involved in the development of myocardial impairments in MS rats and that this effect is mediated probably via the IRS-1/PI3-kinase/AKT pathway.


2021 ◽  
Vol 22 (3) ◽  
pp. 1478
Author(s):  
Jiayin Lu ◽  
Yaoxing Chen ◽  
Zixu Wang ◽  
Jing Cao ◽  
Yulan Dong

Restraint stress causes various maternal diseases during pregnancy. β2-Adrenergic receptor (β2-AR) and Forkhead transcription factor class O 1 (FOXO1) are critical factors not only in stress, but also in reproduction. However, the role of FOXO1 in restraint stress, causing changes in the β2-AR pathway in pregnant mice, has been unclear. The aim of this research was to investigate the β2-AR pathway of restraint stress and its impact on the oxidative stress of the maternal uterus. In the study, maternal mice were treated with restraint stress by being restrained in a transparent and ventilated device before sacrifice on Pregnancy Day 5 (P5), Pregnancy Day 10 (P10), Pregnancy Day 15 (P15), and Pregnancy Day 20 (P20) as well as on Non-Pregnancy Day 5 (NP5). Restraint stress augmented blood corticosterone (CORT), norepinephrine (NE), and blood glucose levels, while oestradiol (E2) levels decreased. Moreover, restraint stress increased the mRNA levels of the FOXO family, β2-AR, and even the protein levels of FOXO1 and β2-AR in the uterus and ovaries. Furthermore, restraint stress increased uterine oxidative stress level. In vitro, the protein levels of FOXO1 were also obviously increased when β2-AR was activated in endometrial stromal cells (ESCs). In addition, phosphorylated-nuclear factor kappa-B p65 (p-NF-κB p65) and its target genes decreased significantly when FOXO1 was inhibited. Overall, it can be said that the β2-AR/FOXO1/p-NF-κB p65 pathway was activated when pregnant mice were under restraint stress. This study provides a scientific basis for the origin of psychological stress in pregnant women.


Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Akira Nishiyama ◽  
Juan Wang ◽  
Shinichi Yachida ◽  
Genevieve Nguyen ◽  
Takuo Hirose ◽  
...  

(Pro)renin receptor ((P)RR) is a component of the Wnt receptor complex (Science, 2010). We have recently demonstrated that (P)RR plays an important role in the tumorigenesis of pancreatic ductal adenocarcinoma via the activation of Wnt/β-catenin signaling pathway (Shibayama et al. Sci Rep. 2015). Since the patients with colon cancer often show aberrantly activated Wnt/β-catenin-dependent signaling pathway by the mutations of its components, we investigated the possible role of (P)RR and Wnt/β-catenin signaling pathway in carcinogenesis of colon cancer. Real-time PCR was used for measuring mRNA levels of (P)RR. Protein levels of (P)RR was determined by Western blotting and immunohistochemistry. Activated β-catenin levels were determined by Western blotting. Cell proliferative ability was evaluated by counting the cell number in cultured colon cancer cell lines, HCT116 and DLD-1 cells. As compared to normal colon tissues (n=6), mRNA and protein levels of (P)RR were increased by 2.6- and 2.2-fold, respectively, in colon cancer tissues (n=9), which were associated with increased activated β-catenin levels (by 2.8-fold, P<0.05). However, plasma soluble (P)RR levels were not changed in patients with colon cancer (n=9). (P)RR and activated β-catenin levels were also increased in HCT116 (by 2.2- and 2.7-fold, n=5, respectively) and DLD-1 cells (by 1.9- and 2.8-fold, n=5, respectively). In these cells, inhibiting (P)RR with an siRNA attenuated the activity of β-catenin and reduced the proliferative abilities (n=5, P<0.05, respectively). These data suggest that (P)RR contributes to the tumorigenesis of colon cancer through the activation of Wnt/β-catenin signaling pathway.


Antioxidants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 236 ◽  
Author(s):  
Margalida Monserrat-Mesquida ◽  
Magdalena Quetglas-Llabrés ◽  
Xavier Capó ◽  
Cristina Bouzas ◽  
David Mateos ◽  
...  

Metabolic syndrome (MetS) is associated with increased risk of developing diabetes and cardiovascular diseases. MetS is also characterized by an increase of oxidative stress which contributes to impaired inflammation, vascular function, and atherosclerosis. The aim was to assess the oxidative stress and inflammatory markers in plasma and PBMCs in adults with or without MetS. Antioxidant and inflammatory parameters were measured in peripheral blood mononuclear cells (PBMCs) of 80 men and 80 women over 55 to 80-years-old residing in the Balearic Islands without previously documented cardiovascular disease. Circulating leukocytes, neutrophils, lymphocytes, basophils, and monocytes were higher in MetS subjects with respect to those without MetS. Plasma levels of malondialdehyde, tumor necrosis factor α (TNFα), and interleukin 6 (IL-6) levels were higher in MetS subjects in both genders, but the superoxide dismutase activity was lower. The myeloperoxidase plasma activity was higher in the MetS male subjects. Higher activities and protein levels of catalase and glutathione reductase in PBMCs were observed in MetS subjects in both genders. Obtained data show that MetS is associated with oxidative stress and a proinflammatory state and with high antioxidant defenses in PBMCs probably derived from a pre-activation state of immune cells.


2018 ◽  
Vol 20 (1) ◽  
pp. 106 ◽  
Author(s):  
Satomi Kagota ◽  
Kana Maruyama-Fumoto ◽  
Saki Iwata ◽  
Miho Shimari ◽  
Shiori Koyanagi ◽  
...  

Perivascular adipose tissue (PVAT) can regulate vascular tone. In mesenteric arteries of SHRSP.Z-Leprfa/IzmDmcr rats (SHRSP.ZF) with metabolic syndrome, vascular dysfunction is compensated by PVAT-dependent mechanisms that disappear with increasing age. In this study, we investigated the mechanisms of the age-related changes and responsible factor(s) involved in the enhancing effects of mesenteric arterial PVAT in SHRSP.ZF. Acetylcholine- and sodium nitroprusside-induced relaxations of isolated arteries were greater with PVAT than without PVAT at 17 and 20 weeks of age (wks), and as expected, this enhancement by the presence of PVAT disappeared at 23 wks. PVAT mRNA levels of angiotensin II type 1 (AT1) receptor-associated protein was less and AT1 receptor was unchanged at 23 wks when compared to 20 wks. At 20 wks, the enhanced acetylcholine-induced relaxation by the presence of PVAT was inhibited by N-acetyl-l-cysteine (NAC). Acetylcholine-induced relaxation of arteries without PVAT was increased in the presence of exogenously added apelin. PVAT mRNA level of apelin was higher in SHRSP.ZF than in control Wistar-Kyoto rats, and the level was decreased with aging. These results suggest that AT1 receptor activation in PVAT, and changes in the regulation of apelin and a NAC-sensitive factor are related to the age-dependent deterioration of the vasodilation enhancing effects of mesenteric arterial PVAT in SHRSP.ZF.


Endocrinology ◽  
2010 ◽  
Vol 151 (11) ◽  
pp. 5255-5266 ◽  
Author(s):  
Angelo Cignarelli ◽  
Mariangela Melchiorre ◽  
Alessandro Peschechera ◽  
Antonella Conserva ◽  
Lucia Adelaide Renna ◽  
...  

The small ubiquitin-like modifier-conjugating enzyme UBC9, involved in protein modification through covalent attachment of small ubiquitin-like modifier and other less defined mechanisms, has emerged as a key regulator of cell proliferation and differentiation. To explore the role of UBC9 in adipocyte differentiation, the UBC9 protein levels were examined in differentiating 3T3-L1 cells. UBC9 mRNA and protein levels were increased 2.5-fold at d 2 and then gradually declined to basal levels at d 8 of differentiation. In addition, UBC9 was expressed predominantly in the nucleus of preadipocytes but shifted to cytoplasmic compartments after d 4, after induction of differentiation. UBC9 knockdown was then achieved in differentiating 3T3-L1 preadipocytes using a specific small interfering RNA. Oil-Red-O staining demonstrated accumulation of large triglyceride droplets in approximately 90% of control cells, whereas lipid droplets were smaller and evident in only 30% of cells treated with the UBC9-specific small interfering RNA. CCAAT/enhancer-binding protein (C/EBP)-δ, peroxisome proliferator-activated receptor-γ, and C/EBPα mRNA levels were increased severalfold 2–6 d after induction of differentiation in control cells, whereas the expression of these transcription factors was significantly lower in the presence of UBC9 gene silencing. Adenovirus-mediated overexpression of a catalytically inactive mutant UBC9 protein in 3T3-L1 cells resulted in no changes in expression of adipogenic transcription factors and conversion to mature adipocytes as compared with control. In conclusion, UBC9 appears to play an important role in adipogenesis. The temporal profile of UBC9 induction and its ability to affect C/EBPδ mRNA induction support a role for this protein during early adipogenesis.


2021 ◽  
Author(s):  
Xiansheng Huang ◽  
Yiqi Zhang ◽  
Wenqiang Zhu ◽  
Piaopiao Huang ◽  
Jingmei Xiao ◽  
...  

Olanzapine, an antipsychotic drug, was reported to induce hypertriglyceridemia, whereas the underlying mechanism remains incompletely understood. This study was to determine the role of apolipoprotein A5 (apoA5) in olanzapine-induced hypertriglyceridemia. In this study, 36 drug-naive and first-episode schizophrenic adult patients (aged 18-60 years) in a multi-center clinical trial (ClinicalTrials.gov NCT03451734) were enrolled. Before and after olanzapine treatment, plasma lipid and apoA5 levels were detected. Moreover, 21 female C57BL/6 J mice (8 weeks old) were divided into 3 groups (n = 7/each group): low-dose olanzapine (3 mg/kg/day), high-dose olanzapine (6 mg/kg/day) and control group. After 6 weeks, plasma glucose, lipids and apoA5 as well as hepatic apoA5 protein and mRNA expression in these animals were detected. In our study in vitro, primary mouse hepatocytes and HepG2 cells were treated with olanzapine of 25, 50, 100 μmol/L, respectively. After 24 hours, apoA5 protein and mRNA levels in hepatocytes were detected. Our study showed that olanzapine treatment significantly increased plasma triglyceride levels and decreased plasma apoA5 levels in these schizophrenic patients. A significant negative correlation was indicated between plasma triglyceride and apoA5 levels in these patients. Consistently, olanzapine dose-dependently increased plasma triglyceride levels and decreased plasma apoA5 levels in mice. Surprisingly, an elevation of hepatic apoA5 protein levels was detected in mice after olanzapine treatment, with no changes of APOA5 mRNA expression. Likewise, olanzapine increased apoA5 protein levels in hepatocytes in vitro, without changes of hepatocyte APOA5 mRNA. Therefore, our study provides the first evidence about the role of apoA5 in olanzapine-induced hypertriglyceridemia. Furthermore, plasma apoA5 reduction, resulting in hypertriglyceridemia, could be attributed to olanzapine-induced inhibition of hepatic apoA5 secretion.


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