Expressions of mRNA and encoded proteins of mitochondrial uncoupling protein genes (UCP1, UCP2, and UCP3) in epicardial and mediastinal adipose tissue and associations with coronary artery disease

ABSTRACT Objective: To evaluate the expression of UCP1, UCP2, and UCP3 mRNA and encoded proteins in epicardial and mediastinal adipose tissues in patients with coronary artery disease (CAD). Subjects and methods: We studied 60 patients with CAD and 106 patients undergoing valve replacement surgery (controls). Expression levels of UCP1, UCP2, and UCP3 mRNA and encoded proteins were measured by quantitative real-time PCR and Western blot analysis, respectively. Results: We found increased UCP1, UCP2, and UCP3 mRNA levels in the epicardial adipose tissue in the CAD versus the control group, and higher UCP1 and UCP3 mRNA expression in the epicardial compared with the mediastinal tissue in the CAD group. There was also increased expression of UCP1 protein in the epicardial tissue and UCP2 protein in the mediastinum tissue in patients with CAD. Finally, UCP1 expression was associated with levels of fasting plasma glucose, and UCP3 expression was associated with levels of high-density lipoprotein cholesterol and low-density cholesterol in the epicardial tissue. Conclusions: Our study supports the hypothesis that higher mRNA expression by UCP genes in the epicardial adipose tissue could be a protective mechanism against the production of reactive oxygen species and may guard the myocardium against damage. Thus, UCP levels are essential to maintain the adaptive phase of cardiac injury in the presence of metabolic disorders.

Anthelmintics nitazoxanide protects against experimental hyperlipidemia and hepatic steatosis in hamsters and mice

Lipid metabolism disorders contribute to hyperlipidemia and hepatic steatosis. It is ideal to develop drugs simultaneous improving both hyperlipidemia and hepatic steatosis. Nitazoxanide is an FDA-approved oral antiprotozoal drug with excellent pharmacokinetic and safety profile. We found that nitazoxanide and its metabolite tizoxanide induced mild mitochondrial uncoupling and subsequently activated AMPK in HepG2 cells. Gavage administration of nitazoxanide inhibited high-fat diet (HFD)-induced increases of liver weight, blood and liver lipids, and ameliorated HFD-induced renal lipid accumulation in hamsters. Nitazoxanide significantly improved HFD-induced histopathologic changes of hamster livers. In the hamsters with pre-existing hyperlipidemia and hepatic steatosis, nitazoxanide also showed therapeutic effect. Gavage administration of nitazoxanide improved HFD-induced hepatic steatosis in C57BL/6J mice and western diet (WD)-induced hepatic steatosis in Apoe -/- mice. The present study suggests that repurposing nitazoxanide as a drug for hyperlipidemia and hepatic steatosis treatment is promising.

Role of HIF-1α in renal injury induced by myocardial ischemia-reperfusion in diabetic rats: relationship with SLC7A11 / 中华麻醉学杂志

Objective:To evaluate the role of hypoxia-inducible factor-1α (HIF-1α) in the renal injury induced by myocardial ischemia-reperfusion (I/R) in diabetic rats and its relationship with solute carrier family7 member11 (SLC7A11).Methods:SPF-grade healthy male Sprague-Dawley rats, aged 4 weeks, weighing 100-130 g, were fed with high-fat and high-sucrose diet freely.The weight of the rats was measured once a week.After the weight of the animals reached 240 g, 1% streptozotocin (STZ)-citrate buffer 35 mg/kg was injected intraperitoneally to induce type 2 diabetes mellitus.After injection of STZ, the animals were fed with high-fat and high-sucrose diet continuously.Blood samples were collected from the tail vein for determination of blood glucose concentrations 1 week later.When random blood glucose was ≥16.7 mmol/L for 3 times, the model of type 2 diabetes mellitus was considered to be established successfully.After the model was established successfully, the animals were fed with high-fat and high-sucrose diet continuously for 6 weeks.Eighteen rats with type 2 diabetes mellitus were selected and divided into 3 groups ( n=6 each) using a random number table method: diabetic sham operation group (group DS), diabetic myocardial I/R group (group DIR) and diabetic myocardial I/R+ HIF-1α agonist DMOG group (DIR+ DMOG group). Twelve non-diabetic rats were divided into 2 groups ( n=6 each) using a random number table method: non-diabetic sham operation group (NS group) and non-diabetic myocardial I/R group (NIR group). The rat myocardial I/R injury model was established by ligating the anterior descending branch of the left coronary artery for 30 min followed by 120 min reperfusion in anesthetized rats.Blood samples were collected from the right internal carotid artery at 120 min of reperfusion for determination of the serum creatinine (Cr), urea nitrogen (BUN) and neutrophil gelatinase-associated lipocalin (NGAL) concentrations (by enzyme-linked immunosorbent assay). Renal tissues were obtained for examination of the pathological changes (by HE staining method) and for determination of the expression of HIF-1α and SLC7A11 (by Western blot). The damage to the renal tubules was scored. Results:Compared with group NS, the concentrations of serum Cr, BUN and NGAL and renal tubular damage score were significantly increased in group DS and group NIR, the expression of HIF-1α and SLC7A11 was down-regulated in group DS, and the expression of HIF-1α and SLC7A11 was up-regulated in group NIR ( P<0.05). Compared with group DS, the concentrations of serum Cr, BUN and NGAL and renal tubular damage score were significantly increased, and the expression of HIF-1α and SLC7A11 was up-regulated in group DIR ( P<0.05). Compared with group NIR, the concentrations of serum Cr, BUN and NGAL and renal tubular damage score were significantly increased, and the expression of HIF-1α and SLC7A11 was down-regulated in group DIR ( P<0.05). Compared with group DIR, the concentrations of serum Cr, BUN and NGAL and renal tubular damage score were significantly decreased, and the expression of HIF-1α and SLC7A11 was up-regulated in group DIR+ DMOG ( P<0.05). Conclusion:HIF-1α is involved in the renal injury induced by myocardial I/R, which is related to regulation of the expression of SLC7A11 in rats.

Mitochondrial function injury mechanism in septic cardiomyopathy / 中国小儿急救医学

Septic cardiomyopathy is a common complication in severe sepsis and septic shock,mito‐chondrial function injury is one of the main aspects of its pathogenesis. The heart is a continuous power or‐gan,needs a lot of ATP to maintain normal systolic and diastolic function. Mitochondrial as the main ATP producing organelles,accounts for about one third of the myocardial volume,which being damaged will be harmful to the myocardial energy supply and cardiac function. This paper introduced the latest research pro‐gress of mitochondrial damage in septic cardiomyopathy,including mitochondrial NO production increase and oxidative stress,Ca2+ overload and mitochondrial membrane permeability increase,mitochondrial uncoupling and mitochondrial homeostasis,also discussed the potential treatments.

Anti-Hypertensive Action of Fenofibrate via UCP2 Upregulation Mediated by PPAR Activation in Baroreflex Afferent Pathway / 神经科学通报·英文版

Fenofibrate, an agonist for peroxisome proliferator-activated receptor alpha (PPAR-α), lowers blood pressure, but whether this action is mediated via baroreflex afferents has not been elucidated. In this study, the distribution of PPAR-α and PPAR-γ was assessed in the nodose ganglion (NG) and the nucleus of the solitary tract (NTS). Hypertension induced by drinking high fructose (HFD) was reduced, along with complete restoration of impaired baroreceptor sensitivity, by chronic treatment with fenofibrate. The molecular data also showed that both PPAR-α and PPAR-γ were dramatically up-regulated in the NG and NTS of the HFD group. Expression of the downstream signaling molecule of PPAR-α, the mitochondrial uncoupling protein 2 (UCP2), was up-regulated in the baroreflex afferent pathway under similar experimental conditions, along with amelioration of reduced superoxide dismutase activity and increased superoxide in HFD rats. These results suggest that chronic treatment with fenofibrate plays a crucial role in the neural control of blood pressure by improving baroreflex afferent function due at least partially to PPAR-mediated up-regulation of UCP2 expression and reduction of oxidative stress.

Mitochondrial uncoupler BAM15 inhibits artery constriction and potently activates AMPK in vascular smooth muscle cells

Our previous studies found that mitochondrial uncouplers CCCP and niclosamide inhibited artery constriction and the mechanism involved AMPK activation in vascular smooth muscle cells. BAM15 is a novel type of mitochondrial uncoupler. The aim of the present study is to identify the vasoactivity of BAM15 and characterize the BAM15-induced AMPK activation in vascular smooth muscle cells (A10 cells). BAM15 relaxed phenylephrine (PE)-induced constricted rat mesenteric arteries with intact and denuded endothelium. Pretreatment with BAM15 inhibited PE-induced constriction of rat mesenteric arteries with intact and denuded endothelium. BAM15, CCCP, and niclosamide had the comparable IC value of vasorelaxation in PE-induced constriction of rat mesenteric arteries. BAM15 was less cytotoxic in A10 cells compared with CCCP and niclosamide. BAM15 depolarized mitochondrial membrane potential, induced mitochondrial fission, increased mitochondrial ROS production, and increased mitochondrial oxygen consumption rate in A10 cells. BAM15 potently activated AMPK in A10 cells and the efficacy of BAM15 was stronger than that of CCCP, niclosamide, and AMPK positive activators metformin and AICAR. In conclusion, BAM15 activates AMPK in vascular smooth muscle cells with higher potency than that of CCCP, niclosamide and the known AMPK activators metformin and AICAR. The present work indicates that BAM15 is a potent AMPK activator.

Mitochondrial uncoupler triclosan induces vasorelaxation of rat arteries

Our previous studies found that mitochondrial uncouplers induced vasodilation. Triclosan, the broad spectrum antibacterial agent, is the active ingredient in soaps and toothpastes. It was reported that triclosan induced mitochondrial uncoupling, so we aim to investigate the effects of triclosan on vascular function of rat mesenteric arteries and aorta. The isometric tension of rat mesenteric artery and thoracic aorta was recorded by multi-wire myograph system. The cytosolic [Ca], mitochondrial reactive oxygen species (mitoROS), and mitochondrial membrane potential of smooth muscle cells (A10 cells) were measured using laser scanning confocal microscopy. Triclosan treatment relaxed phenylephrine (PE)- and high K(KPSS)-induced constriction, and pre-treatment with triclosan inhibited PE- and KPSS-induced constriction of rat mesenteric arteries. In rat thoracic aorta, triclosan also relaxed PE- and KPSS-induced constriction. Triclosan induces vasorelaxation without involving Kchannel activation in smooth muscle cells of arteries. Triclosan treatment increased cytosolic [Ca], mitochondrial ROS production and depolarized mitochondrial membrane potential in A10 cells. In conclusion, triclosan induces mitochondrial uncoupling in vascular smooth muscle cells and relaxes the constricted rat mesenteric arteries and aorta of rats. The present results suggest that triclosan would indicate vasodilation effect if absorbed excessively.

Protective effect and its mechanism of curcumin on ischemia-reperfusion injury of cerebral cortex in rats / 解放军医学杂志

Objective To investigate the effect of curcumin pretreatment on the expression of uncoupling protein 2 (UCP2) and mitochondrial transcription factor A (MTFA) in rats' cerebral cortex against focal ischemia reperfusion injury. Methods Eighty male SD rats weighed 220g-300g were randomly divided into 4 groups: sham-operated group, ischemia/reperfusion (I/R) group, curcumine 50mg/kg+I/R (low dose) group, and curcumine 100mg/kg+I/R (high dose) group. The common carotid artery, external carotid artery and internal carotid artery on the right side were exposed in the sham-operated group. Animals of the other groups were subjected to a 2-hour period of right middle cerebral artery occlusion, followed by 24 hours of reperfusion, and then they were sacrificed. Curcumin was administered (ip) in a dose of 50mg/kg (low dose group) or 100mg/kg (high dose group) for 5 days, respectively, prior to arterial occlusion. The pathological changes in neurons and their mitochondria in the cerebral cortex supplied by middle cerebral artery were observed with Nissl staining and electron microscope, respectively. The expressions of UCP2 and MTFA in corresponding cotex were assessed by immunohistochemistry and RT-PCR. Results Compared with sham-operated group, animals in I/R group presented edema of neurons in the corresponding cortex, reduction in the number of Nissl bodies, and swelling of mitochondria with broken, even lysis of cristae. Low dose and high dose of curcumin pretreatment before brain ischemia significantly alleviated the loss of neurons and the damage of mitochondria, accompanied with an increase in the expression of UCP2 and TFAM (P<0.05), and the changes appeared a dose-dependent manner (P<0.05). Conclusions Curcumin may prevent neurons from focal cerebral ischemia reperfusion injury by up-regulating UCP2 and MTFA. Regulation of mitochondrial biogenesis may probably be a potential target of curcumin as a neuroprotective drug.

Uncoupling protein 4 and its roles in the central nervous system diseases / 国际脑血管病杂志

Uncoupling protein 4 (UCP4) is a member of the multigenic uncoupling proteins (UCPs), specific expressing in the cerebral cortex and hippocampus. UCP4 plays an important role in Parkinson's disease, multiple sclerosis, epilepsy, stroke, brain trauma and other central nervous system diseases by uncoupling, decreasing mitochondrial membrane potential,regulating Ca2+ homeostasis and oxidative stress. This article reviews UCP4 and its roles in the central nervous system diseases in order to provide certain basis for the development of UCP4targeted medication.

Uncoupling Protein 2 (UCP2) and p53 Expression in Invasive Ductal Carcinoma of Breast

BACKGROUND: Uncoupling protein 2 (UCP2) is a recently identified mitochondrial inner membrane anion carrier and a negative regulator of reactive oxygen species production. In this study, we evaluated the characteristics and relationships of UCP2 and p53 expression in breast cancer tissues. METHODS: Tissue microarray slides from 107 cases of invasive ductal carcinoma of the breast were constructed, UCP2 and p53 immunohistochemical staining was conducted, and clinicopathological correlations were investigated. RESULTS: UCP2 expression in invasive ductal carcinoma was high in 53 cases (49.5%), while p53 expression in invasive ductal carcinoma was high in 37 cases (34.6%). UCP2 expression was correlated significantly with histological grade (p = 0.038) and mitotic count (p = 0.050). UCP2 expression was correlated significantly with p53 expression in invasive ductal carcinoma of the breast (p = 0.045). UCP2 expression (p = 0.8308) and p53 expression (p = 0.3292) showed no significant difference for the overall survival rate in patients with invasive ductal carcinoma. CONCLUSIONS: UCP2 expression in invasive ductal carcinoma increased proportionally with histological grade and mitotic count. High UCP2 expression in invasive ductal carcinoma was observed in conjunction with high p53 expression.

Activation of PPARgamma induces profound multilocularization of adipocytes in adult mouse white adipose tissues

We sought to determine the effects of activation of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) on multilocularization of adipocytes in adult white adipose tissue (WAT). Male C57BL/6 normal, db/db, and ob/ob mice were treated with agonists of PPAR-gamma, PPAR-alpha, or beta3-adrenoceptor for 3 weeks. To distinguish multilocular adipocytes from unilocular adipocytes, whole-mounted adipose tissues were co-immunostained for perilipin and collagen IV. PPAR-gamma activation with rosiglitazone or pioglitazone induced a profound change of unilocular adipocytes into smaller, multilocular adipocytes in adult WAT in a time-dependent, dose-dependent, and reversible manner. PPAR-alpha activation with fenofibrate did not affect the number of locules or remodeling. db/db and ob/ob obese mice exhibited less multilocularization in response to PPAR-gamma activation compared to normal mice. Nevertheless, all adipocytes activated by PPAR-gamma contained a single nucleus regardless of locule number. Multilocular adipocytes induced by PPAR-gamma activation contained substantially increased mitochondrial content and enhanced expression of uncoupling protein-1, PPAR-gamma coactivator-1-alpha , and perilipin. Taken together, PPAR-gamma activation induces profound multilocularization and enhanced mitochondrial biogenesis in the adipocytes of adult WAT. These changes may affect the overall function of WAT.

Association of UCP1 Genetic Polymorphisms with Blood Pressure among Korean Female Subjects

Recent studies have provided some clues with regard to the relationship existing between uncoupling protein 1 (UCP1) and blood pressure in animal experiments. In an attempt to determine the genetic polymorphisms that are associated with blood pressure in humans, we have analyzed genetic polymorphisms in UCP1 gene. In this study, we assessed the association between UCP1 genotypes and systolic blood pressure (SBP) and diastolic blood pressure (DBP), in a population comprised of 832 Korean female subjects, using a general linear model, which was adjusted for age and body mass index (BMI). Among 4 genetic polymorphisms and the haplotypes constructed from them, haplotype3 of UCP1, UCP1-ht3[GAGA], evidenced significant associations with SBP (p=0.005) and DBP (p=0.013). However, this haplotype was not significantly associated with obesity phenotypes, including BMI or fat mass (p>0.05), thereby suggesting that its association with blood pressure was independent of obesity phenotypes.

Swim training improves leptin receptor deficiency-induced obesity and lipid disorder by activating uncoupling proteins

Leptin receptor deficiency causes morbid obesity and hyperlipidemia in mice. Since physical exercise enhances energy expenditure, it is an important part of successful weight-control regimens. We investigated the mechanism by which swim training regulates leptin receptor deficiency-induced obesity and lipid disorder in a mouse model of obesity (obese db/db mouse). Swim training for 6 weeks significantly decreased body weight gain and adipose tissue mass in both sexes of obese and lean mice, compared to their respective sedentary controls. These effects were particularly evident in obese mice. Swim training also caused significant decreases in serum levels of triglycerides, free fatty acids and total cholesterol in both obese and lean mice. In obese mice, swim training increased the levels of mRNAs and proteins encoding uncoupling protein 1 (UCP1), UCP2 and UCP3 in brown adipose tissue, white adipose tissue and skeletal muscle, respectively. In conclusion, these findings suggest that, in mice, swim training can effectively prevent body weight gain, adiposity and lipid disorders caused by leptin receptor deficiency, in part through activation of UCPs in adipose tissue and skeletal muscle, which may contribute to alleviating metabolic syndromes, such as obesity, hyperlipidemia and type 2 diabetes.