Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

C75, a known inhibitor of fatty acid synthase is postulated to cause significant weight loss through decreased hypothalamic neuropeptide Y (NPY) production. Peripherally, C75, an alpha-methylene-gamma-butyrolactone, reduces adipose tissue and fatty liver, despite high levels of malonyl-CoA. To investigate this paradox, we studied the effect of C75 on fatty acid oxidation and energy production in diet-induced obese (DIO) mice and cellular models. Whole-animal calorimetry showed that C75-treated DIO mice had a 50% greater weight loss, and a 32.9% increased production of energy because of fatty acid oxidation, compared with paired-fed controls. Etomoxir, an inhibitor of carnitine O-palmitoyltransferase-1 (CPT-1), reversed the increased energy expenditure in DIO mice by inhibiting fatty acid oxidation. C75 treatment of rodent adipocytes and hepatocytes and human breast cancer cells increased fatty acid oxidation and ATP levels by increasing CPT-1 activity, even in the presence of elevated concentrations of malonyl-CoA. Studies in human cancer cells showed that C75 competed with malonyl-CoA, as measured by CPT-1 activity assays. Thus, C75 acts both centrally to reduce food intake and peripherally to increase fatty acid oxidation, leading to rapid and profound weight loss, loss of adipose mass, and resolution of fatty liver. The pharmacological stimulation of CPT-1 activity is a novel finding. The dual action of the C75 class of compounds as fatty acid synthase inhibitors and CPT-1 agonists has therapeutic implications in the treatment of obesity and type II diabetes.
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PMID:C75 increases peripheral energy utilization and fatty acid oxidation in diet-induced obesity. 1209 27

Proteolytic degradation of recombinant proteins is an industry-wide challenge in host organisms such as Escherichia coli. These proteases have been linked to stresses, such as the stringent and heat-shock responses. This study reports the dramatic up-regulation of protease activity in an industrial recombinant E. coli fermentation upon induction. The objective of this project was to detect and characterize up-regulated proteases due to recombinant AXOKINE overexpression upon IPTG induction. AXOKINE is a 22-kDa protein currently in clinical trials as a therapeutic for obesity associated with diabetes. AXOKINE was expressed in both the soluble and inclusion body fractions in E. coli. Sodium dodecyl sulfate gelatin-polyacrylamide gel electrophoresis (SDS-GPAGE) was used to analyze the up-regulated protease activity. Western blot analysis showed degraded AXOKINE in both the soluble and insoluble fractions. Protease inhibitors were used to characterize the proteases. The proteases were ethylenediaminetetraacetic acid (EDTA) sensitive. The protease activity increased in the presence of phenyl-methyl sulfonyl-fluoride (PMSF), a serine protease inhibitor. The incubation buffer composition was varied with respect to Mg2+ and ATP, and the protease activity was ATP independent and Mg2+ dependent. A two-dimensional electrophoresis technique was used to estimate the pI of the proteases to be between 2.9 and 4.0.
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PMID:Characterization of up-regulated proteases in an industrial recombinant Escherichia coli fermentation. 1207 55

It is becoming evident that insulin resistance of white adipose tissue is a major factor underlying the cardiovascular risk of obesity. Impaired fat storage rather than altered glucose metabolism in adipocytes probably contributes to development of insulin resistance in muscle and other tissues, in particular via increased delivery of nonesterified fatty acids into circulation. Lipid metabolism of adipose tissue is affected by the energy status of fat cells. In vitro experiments indicated the dependence of both lipogenesis and lipolysis on ATP levels in adipocytes. Thus, respiratory uncoupling in adipocytes that results in stimulation of energy dissipation and depression of ATP synthesis may contribute to the control of lipid metabolism, adiposity, and insulin sensitivity. This notion is supported by the expression of UCPs in adipocytes, for example, UCP2, UCP5, as well as some protonophoric anion transporters, and by induction of UCP1 and UCP3 in white fat by pharmacological treatments that reduce adiposity. A negative correlation between expression of UCPs in adipocytes and accumulation of white fat was also found. Expression of UCP1 from the adipose-specific promoter in the aP2-Ucp1 transgenic mice mitigated obesity induced by genetic or dietary factors. The obesity resistance, accompanied by respiratory uncoupling in adipocytes and increased energy expenditure, resulted from ectopic expression of UCP1 in white, but not brown fat. Probably due to depression of the ATP/ADP ratio, both fatty acid synthesis and lipolytic action of norepinephrine in adipocytes of transgenic mice were relatively low. Expression of regulatory G-proteins, which are essential for both catecholamine and insulin signaling in adipocytes, was also altered by ectopic UCP1. These results support the role of protonophoric proteins in adipocytes in the control of adiposity and insulin sensitivity. Antidiabetic effects of thiazolidinediones, fibrates, beta(3)-adrenoreceptor agonists, dietary n-3 PUFAs, and leptin may be explained at least partially by their effects on the energy and hence also the lipid metabolism of fat cells.
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PMID:Modulation of lipid metabolism by energy status of adipocytes: implications for insulin sensitivity. 1207 39

Specialized neurons utilize glucose as a signaling molecule to alter their firing rate. Glucose-excited (GE) neurons increase and glucose-inhibited (GI) neurons reduce activity as ambient glucose levels rise. Glucose-induced changes in the ATP-to-ADP ratio in GE neurons modulate the activity of the ATP-sensitive K(+) channel, which determines the rate of cell firing. The GI glucosensing mechanism is unknown. We postulated that glucokinase (GK), a high-Michaelis constant (K(m)) hexokinase expressed in brain areas containing populations of GE and GI neurons, is the controlling step in glucosensing. Double-label in situ hybridization demonstrated neuron-specific GK mRNA expression in locus ceruleus norepinephrine and in hypothalamic neuropeptide Y, pro-opiomelanocortin, and gamma-aminobutyric acid neurons, but it did not demonstrate this expression in orexin neurons. GK mRNA was also found in the area postrema/nucleus tractus solitarius region by RT-PCR. Intracarotid glucose infusions stimulated c-fos expression in the same areas that expressed GK. At 2.5 mmol/l glucose, fura-2 Ca(2+) imaging of dissociated ventromedial hypothalamic nucleus neurons demonstrated GE neurons whose intracellular Ca(2+) oscillations were inhibited and GI neurons whose Ca(2+) oscillations were stimulated by four selective GK inhibitors. Finally, GK expression was increased in rats with impaired central glucosensing (posthypoglycemia and diet-induced obesity) but was unaffected by a 48-h fast. These data suggest a critical role for GK as a regulator of glucosensing in both GE and GI neurons in the brain.
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PMID:Glucokinase is the likely mediator of glucosensing in both glucose-excited and glucose-inhibited central neurons. 1208 33

The UCPs are integral membrane proteins of the mitochondrial respiration from oxidative phosphorylation, diminishing the resulting production of ATP and instead yielding dissipative heat. The action of those proteins creates a futile cycle that decreases the metabolic efficiency of the organism. Thus UCPs provide new clue to obesity's causes. This study was designed to investigate the effect of UCP gene on chicken fatness traits. The fifth generation population of divergent selection broiler line, Hyline Brown layer and three native breeds (shiqiza, Beijing You, baier) were used in this research. Body weight and body composition traits were measured in broiler lines at 7 weeks of age. Primers for the 3'-untranslator region in UCP were designed from database of chicken genomic sequence. Polymorphisms were detected by PCR-SSCP and DNA sequencing. The results showed that there was significant difference (P < 0.01) in the frequency of genotype among breeds except broiler vs Beijing You and Baier vs Hyline Brown layer in mutation sites detected by the two pairs of primers. The distribution of genotype in Beijing You and broiler had no difference. It deduced that Beijing You belongs to the native breed that has dominant meat type traits and has the same genetic background with broiler. Baier and Hyline Brown Layer have no difference in the genotype, it can be viewed as they have same genetic background. A A/C mutation at base position 1197 was found among individuals in broiler line and the least square analysis showed that BB birds had significant lower (P < 0.01) abdominal fat weight and percentage of abdominal fat than AB or AA birds. From the results we can putatively draw the conclusion that UCP gene is the major gene to affect the fatness traits or it links with the major gene.
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PMID:[The study of the uncoulping protein gene as the candidate gene for fatness traits in chicken]. 1209 23

The uncoupling protein-1 (UCP1) homologues UCP2 and UCP3 are able to uncouple ATP production from mitochondrial respiration, thereby dissipating energy as heat and affecting energy metabolism efficiency. In contrast to UCP1, which plays an important role in adaptive thermogenesis, UCP2 and UCP3 do not have a primary role in the regulation of energy metabolism. UCP2, which is expressed in a wide variety of tissues, including white adipose tissue, skeletal muscle and tissues of the immune system, has been suggested to affect the production of reactive oxygen species. UCP2 has also been suggested to regulate the [ATP]/[ADP] ratio and was recently shown to influence insulin secretion in the beta-cells of the pancreas. UCP3, in contrast, is expressed predominantly in skeletal muscle and has been associated with whole-body energy metabolism. However, the primary function of UCP3 is not the regulation of energy metabolism. For example, fasting, a condition attenuating energy expenditure, upregulates UCP3 expression. Moreover, UCP3-knockout mice have a normal metabolic rate. The exact function of UCP3 therefore remains to be elucidated, but putative roles for UCP3 include involvement in the regulation of ROS, in mitochondrial fatty acid transport and in the regulation of glucose metabolism in skeletal muscle. Whatever the primary function of these novel uncoupling proteins, a secondary effect via uncoupling might allow them to influence (but not to regulate) energy metabolism, which would be consistent with the observations from linkage and association studies. Therefore, UCP2 and UCP3 remain interesting targets for pharmacological upregulation in the treatment of obesity and diabetes.
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PMID:UCP2 and UCP3 in muscle controlling body metabolism. 1211 Jun 61

The Third Report of the National Cholesterol Education Program's Adult Treatment Panel (ATP III) has an extensive section on nonpharmacologic therapy for those with abnormal blood lipids. ATP III focused on the high-saturated fat atherogenic diet, obesity, and sedentary lifestyle and recommended a program of therapeutic lifestyle change (TLC). This review discusses several issues, including 1) why ATP III changed from the Step I and Step II diets to TLC; 2) the benefits of keeping trans fatty acid intake low and the addition of viscous fiber and plant stanol/sterol esters to reduce low-density lipoprotein cholesterol beyond that seen with the Step II diet; 3) the de-emphasis on total fat and a sharper focus on the kinds of fat ingested in the new guidelines; 4) the endorsement of regular physical activity and weight loss as important first steps in reversing the unwanted metabolic effects of the metabolic syndrome; and 5) the emphasis of health-promoting aspects of the diet that include, among other things, fish and omega-3 fatty acids. At all stages of TLC, ATP III encourages the referral to registered dietitians or other qualified nutritionists for medical nutrition therapy. TLC and the ATP III guidelines should provide guidance to practitioners who wish to get low-density lipoprotein cholesterol to goal (whether or not drugs are used), prevent or treat the metabolic syndrome, and improve the overall health of the patient.
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PMID:Therapeutic lifestyle change and Adult Treatment Panel III: evidence then and now. 1236 90

Obesity is a major risk factor associated with a variety of human disorders. While its involvement in disorders such as diabetes, coronary heart disease and cancer have been well characterized, it remains to be determined if obesity has a detrimental effect on the nervous system. To address this issue we determined whether obesity serves as a risk factor for neurotoxicity. Model neurotoxicants, methamphetamine (METH) and kainic acid (KA), which are known to cause selective neurodegeneration of anatomically distinct areas of the brain, were evaluated using an animal model of obesity, the ob/ob mouse. Administration of METH and KA resulted in mortality among ob/ob mice but not among their lean littermates. While METH caused dopaminergic nerve terminal degeneration as indicated by decreased striatal dopamine (49%) and tyrosine hydroxylase protein (68%), as well as an increase in glial fibrillary acidic protein by 313% in the lean mice, these effects were exacerbated under the obese condition (96%, 86% and 602%, respectively). Similarly, a dosage of KA that did not increase glial fibrillary acidic protein in lean mice increased the hippocampal content of this protein (93%) in ob/ob mice. KA treatment resulted in extensive neuronal degeneration as determined by Fluoro-Jade B staining, decreased hippocampal microtubule-associated protein-2 immunoreactivity and increased reactive gliosis in ob/ob mice. The neurotoxic outcome in ob/ob mice remained exacerbated even when lean and ob/ob mice were dosed with METH or KA based only on a lean body mass. Administration of METH or KA resulted in up-regulation of the mitochondrial uncoupling protein-2 to a greater extent in the ob/ob mice, an effect known to reduce ATP yield and facilitate oxidative stress and mitochondrial dysfunction. These events may underlie the enhanced neurotoxicity seen in the obese mice. In summary, our results implicate obesity as a risk factor associated with chemical- and possibly disease-induced neurodegeneration.
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PMID:Obesity exacerbates chemically induced neurodegeneration. 1245 1

Uncoupling proteins(UCP) are carrier proteins in mitochondria. In eukaryotic cells, ATP is generated by oxidative phosphorylation, an energetic coupling at mitochondria level. The oxidative reactions occurring in the respiratory chain generate an electrochemical proton gradient at both sides of the inner membrane of mitochondria. This gradient is used by the ATP synthase to phosphorylate ADP into ATP. The coupling of cell respiration with ADP phosphorylation is only partial in brown adipose tissue (BAT) mitochondria, where UCP causes a reentry of protons into the matrix and abolishes the electrochemical proton gradient. The liberated energy is then dissipated as heat and the synthesis of ATP is reduced. Recently, the cloning of new UCPs expressed in other tissues revealed the importance of this kind of regulation of respiratory control in metabolism and energy expenditure. The newly characterized UCPs are potential target drugs for obesity treatment, which could be favor of energy expenditure and diminish the metabolic efficiency.
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PMID:[Characters of uncoupling protein and its relation with obesity]. 1256 30

Energy exists as organic molecules and heat in living organisms. In adult mammals, body weight and fat content remain unchanged if energy intake is strictly equivalent to energy expenditure. In other words, regulation of body weight requires energy of foods to be entirely dissipated as heat. Imbalance between ingested energy and thermogenesis induces obesity or thinness. Alterations of food intake or energy expenditure represent the two causes of body weight disturbance. It is accepted that individuals differ in food efficiency i.e. ability to metabolize foods and store fat or totally burn nutrients. Mechanisms of food efficiency and futile cycles are presented. I started my research work analysing thermogenic mechanism in brown adipose tissue. Actually, in addition to white adipose tissue which is the major type of adipose tissue, mammals own another type of adipose tissue referred to as brown adipose tissue. This later tissue is an activatable thermogenic organ which oxidizes fatty acids and releases heat in blood stream. Brown fat is activated during exposure to the cold (in rodents), at birth, and during arousal in hibernators. My initial work helped to characterize a mitochondrial protein named uncoupling protein or UCP which is responsible for activation of fatty acid oxidation and heat production in brown adipocytes. Actually, in most cells, fifty per cent of oxidation energy is recovered as ATP in mitochondria through the process of coupling of respiration to ADP phosphorylation. In contrast to mitochondria of most tissues, brown adipocyte mitochondria can escape the obligatorily coupling of respiration and waste almost ninety per cent of respiration energy as thermogenesis. UCP characterization and its molecular cloning as well as antibodies obtention were used to better understand cellular thermogenesis. Brown adipocytes were identified in babies and adult patients with pheochromocytoma. More recently, research on the brown fat UCP helped us to identify UCP2, a UCP homolog present in most human and animal tissues. A family of UCPs exist in animals and plants. These UCPs may function as mitochondrial uncouplers. However, the ancient function of the UCPs may be rather associated to adaptation to oxygen and control of free radicals than to thermogenesis. Further studies of UCPs will improve the knowledge of mitochondrial metabolism and substrate oxidation. In other respects, analysis of molecular mechanisms controlling respiration uncoupling may contribute to new strategies of treatment of metabolic disorders such as obesity.
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PMID:[To burn or to store]. 1273 25


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