Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0015695 (fatty liver)
 13,941 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Worldwide, one of the most prevalent forms of chronic disease is alcoholic fatty liver, which may progress to more severe forms of liver injury including steatohepatitis, fibrosis, and cirrhosis. The molecular mechanisms by which ethanol consumption causes accumulation of hepatic lipid are multiple and complex. Chronic ethanol exposure is thought to cause enhanced hepatic lipogenesis and impaired fatty acid oxidation by inhibiting key hepatic transcriptional regulators such as AMP-activated kinase (AMPK), sirtuin 1 (SIRT1), PPAR-gamma coactivator alpha (PGC-1alpha), peroxisome proliferator-activated receptor alpha (PPARalpha), and sterol regulatory element-binding protein 1 (SREBP-1). Adiponectin is an adipose-derived hormone with a variety of beneficial biological functions. Increasing evidence suggests that altered adiponectin production in adipose tissue and impaired expression of hepatic adiponectin receptors (AdipoRs) are associated with the development of alcoholic liver steatosis in several rodent models. More importantly, studies have demonstrated a protective role of adiponectin against alcoholic liver steatosis. The hepato-protective effect of adiponectin is largely mediated by the coordination of multiple signaling pathways in the liver, leading to enhanced fat oxidation, reduced lipid synthesis and prevention of hepatic steatosis. This review begins with an assessment of the current understanding of the role of adiponectin and its receptors in the regulation of lipid homeostasis in liver, with emphasis on their relationship to the development of alcoholic liver steatosis. Following sections will review hepatic signaling molecules involved in the protective actions of adiponectin against alcoholic fatty liver and summarize the current knowledge of regulatory mechanisms of adiponectin expression and secretion in response to chronic ethanol exposure. We will conclude with a discussion of potential strategies for treating human alcoholic fatty liver disease (AFLD), including nutritional and pharmacological modulation of adiponectin and its receptors.
 ...
PMID:Adiponectin and alcoholic fatty liver disease. 1870 50

Non-alcoholic steatohepatitis (NASH) may be associated with a number of clinical conditions, but it occurs most commonly in patients with insulin resistance. There is as yet no established disease-modifying treatment, and a safe and broadly available agent that targets hepatic steatosis, insulin resistance, inflammation and fibrosis is necessary. The polyphenolic compound curcumin exhibits antioxidant and anti-inflammatory properties, inhibits NF-kappaB and activates PPAR-gamma. In rodents, curcumin prevents dietary-induced hepatic steatosis, hepatic stellate cell activation and production of fibrotic proteins, and ameliorates steatohepatitis induced by the intake of alcohol or a methionine-choline-deficient diet. Indirect evidence suggests that curcumin may improve insulin sensitivity in diabetes and inflammatory states. The present paper reviews the numerous cellular and animal studies indicating that curcumin attenuates many of the pathophysiological processes involved in the development and progression of NASH. It is suggested that basic and clinical studies on curcumin in the development and progression of NASH are indicated.
 ...
PMID:Therapeutic potential of curcumin in non-alcoholic steatohepatitis. 1907 6

Although the definition of the phenotype is imprecise, cardiometabolic syndrome (CMS) includes a constellation of complex diseases such as type 2 diabetes, dislipidemias, central obesity and hypertension, proinflammatory and prothrombotic states, ovarian polycystosis and fatty liver. The genetics of each disease is complex in itself and varies in spectrum from monogenic and syndromic models of inheritance, usually rare, to the most common polygenic and multifactorial forms. In addition, human studies using the candidate-gene approach indicate that common genetic variants of several genes are associated with the development of CMS. Genome-wide scans have also provided several chromosomal regions associated with some of the components of CMS. In addition, through comparative genomics animal models can generate a map for candidate loci in humans and a promising approach is offered by bioinformatic tools for gene prioritization. Lastly, the involvement of genes whose products are already the targets for approved drugs, such as SLC6A4, PPARalpha and PPARgamma , in the development of CMS suggests new avenues for CMS pharmacological treatment.
 ...
PMID:Genetics of the cardiometabolic syndrome: new insights and therapeutic implications. 1912 94

Menopause, an age-related loss of ovarian hormone production, promotes increased adiposity and insulin resistance. However, the diet-independent mechanism by which loss of ovarian function promotes increased adipose tissue mass and associated metabolic pathologies remains unclear. To address this question, we monitored food intake and weight gain of ovariectomized (OVX) mice and sham OVX (SHM) mice for 12 wk. Although food intake was similar, OVX mice gained 25% more weight than SHM mice. Moreover, the OVX mice accumulated 4.7- and 4.4-fold more perigonadal and inguinal adipose tissue by weight, respectively, with 4.4-fold (perigonadal, P < 0.001) and 5.3-fold (inguinal, P < 0.01) larger adipocytes and no change in adipocyte cell number. OVX-induced adiposity was coincident with an 18% decrease in metabolic rate during the dark phase (P = 0.001) as well as an 11% decrease during the light phase (P = 0.03). In addition, ambulatory activity levels of OVX mice were decreased only during the dark phase (40%, P = 0.008). OVX mice displayed evidence of immune infiltration and inflammation in adipose tissue, because perigonadal and inguinal adipose depots from OVX mice had increased expression of TNFalpha, iNOS, CD11c, and other hallmarks of adipose tissue inflammation. In contrast, expression of the T cell marker CD3 (3.5-fold, P = 0.03) and Th1 cytokine interferon-gamma (IFNgamma) (2.6-fold, P = 0.02) were elevated in perigonadal but not sc fat. Finally, histology revealed OVX-specific liver hepatic steatosis, coincident with increased PPARgamma gene expression and downstream lipogenic gene expression. In summary, OVX in mice decreases energy expenditure, without altering energy intake, resulting in adipocyte hypertrophy, adipose tissue inflammation, and hepatic steatosis.
 ...
PMID:Reduced energy expenditure and increased inflammation are early events in the development of ovariectomy-induced obesity. 1917 42

Omega-3-polyunsaturated fatty acids (omega-3-PUFAs) have well-documented protective effects that are attributed not only to eicosanoid inhibition but also to the formation of novel biologically active lipid mediators (i.e., resolvins and protectins). In this study, we examined their effects on ob/ob mice, an obesity model of insulin resistance and fatty liver disease. Dietary intake of omega-3-PUFAs had insulin-sensitizing actions in adipose tissue and liver and improved insulin tolerance in obese mice. Genes involved in insulin sensitivity (PPARgamma), glucose transport (GLUT-2/GLUT-4), and insulin receptor signaling (IRS-1/IRS-2) were up-regulated by omega-3-PUFAs. Moreover, omega-3-PUFAs increased adiponectin, an anti-inflammatory and insulin-sensitizing adipokine, and induced AMPK phosphorylation, a fuel-sensing enzyme and a gatekeeper of the energy balance. Concomitantly, hepatic steatosis was alleviated by omega-3-PUFAs. A lipidomic analysis with liquid chromatography/mass spectrometry/mass spectrometry revealed that omega-3-PUFAs inhibited the formation of omega-6-PUFA-derived eicosanoids, while triggering the formation of omega-3-PUFA-derived resolvins and protectins. Moreover, representative members of these lipid mediators, namely resolvin E1 and protectin D1, mimicked the insulin-sensitizing and antisteatotic effects of omega-3-PUFAs and induced adiponectin expression to a similar extent that of rosiglitazone, a member of the thiazolidinedione family of antidiabetic drugs. Taken together, these findings uncover beneficial actions of omega-3-PUFAs and their bioactive lipid autacoids in preventing obesity-induced insulin resistance and hepatic steatosis.
 ...
PMID:Obesity-induced insulin resistance and hepatic steatosis are alleviated by omega-3 fatty acids: a role for resolvins and protectins. 1921 25

The aim was to examine the role of cyclooxygenase (COX)-2-mediated inflammation in the development of obese linked insulin resistance and fatty liver. The rats were fed separately regular diet (CONT), high-fat diet (HFD) ad libitum, or energy restrictedly for 12 weeks. Rats fed HFD ad libitum were further divided into three subgroups co-treated with vehicle (HFa), or a selective COX-2 inhibitor celecoxib (HFa-Cel) or mesulid (HFa-Mes). Euglycemic hyperinsulinemic clamp (EHC) experiment was performed at the end of study. Another set of rats with similar grouping was further divided into those with a 4, 8, or 12-week intervention period for hepatic sampling. Body weight was increased significantly and similarly in HFa, HFa-Cel, and HFa-Mes. Time-dependent increases in plasma insulin, glucose, 8-isoprostanes, leptin levels, homeostasis model assessment of insulin resistance (HOMA-IR) and hepatic triglyceride contents shown in HFa were significantly reversed in HFa-Cel and HFa-Mes. During EHC period, the reduction in stimulation of whole body glucose uptake, suppression of hepatic glucose production and metabolic clearance rate of insulin shown in HFa were significantly reversed in HFa-Cel and HFa-Mes. The enhanced COX-2 and tumor necrosis factor-alpha (TNF-alpha) but attenuated PPAR-gamma and C/EBP-alpha mRNA expressions in epididymal fat shown in HFa were significantly reversed in HFa-Cel and HFa-Mes. The increases in average cell size of adipocytes and CD68 positive cells shown in HFa were also significantly reversed in HFa-Cel and HFa-Mes. Our findings suggest that COX-2 activation in fat inflammation is important in the development of insulin resistance and fatty liver in high fat induced obese rats.
 ...
PMID:COX-2-mediated inflammation in fat is crucial for obesity-linked insulin resistance and fatty liver. 1924 74

Cyclic nucleotide phosphodiesterases (PDEs) are important regulators of signal transduction processes mediated by cAMP and cGMP. One PDE family member, PDE3B, plays an important role in the regulation of a variety of metabolic processes such as lipolysis and insulin secretion. In this study, the cellular localization and the role of PDE3B in the regulation of triglyceride, cholesterol and glucose metabolism in hepatocytes were investigated. PDE3B was identified in caveolae, specific regions in the plasma membrane, and smooth endoplasmic reticulum. In caveolin-1 knock out mice, which lack caveolae, the amount of PDE3B protein and activity were reduced indicating a role of caveolin-1/caveolae in the stabilization of enzyme protein. Hepatocytes from PDE3B knock out mice displayed increased glucose, triglyceride and cholesterol levels, which was associated with increased expression of gluconeogenic and lipogenic genes/enzymes including, phosphoenolpyruvate carboxykinase, peroxisome proliferator-activated receptor gamma, sterol regulatory element-binding protein 1c and hydroxyl-3-methylglutaryl coenzyme A reductase. In conclusion, hepatocyte PDE3B is localized in caveolae and smooth endoplasmic reticulum and plays important roles in the regulation of glucose, triglyceride and cholesterol metabolism. Dysregulation of PDE3B could have a role in the development of fatty liver, a condition highly relevant in the context of type 2 diabetes.
 ...
PMID:Phosphodiesterase 3B is localized in caveolae and smooth ER in mouse hepatocytes and is important in the regulation of glucose and lipid metabolism. 1926 49

Lecithin is an essential biological component and widely used as a nutritional supplement for protecting cells from oxidation, increase fat burning and preventing cardiovascular disease. Lecithin contains fatty acids identified as the peroxisome proliferator-activated receptor (PPAR) agonists. However, the role of lecithin in adipogenesis and lipogenesis remains elusive. 3T3-L1 cells and mouse primary preadipocytes were used to characterize the properties of lecithin related to adipogenesis and lipogenesis. We found that lecithin promoted adipocyte differentiation and differentiation-specific gene expression, and increased triglycerides and free fatty acid levels in the adipocytes. These effects are independent of the clonal expansion of 3T3-L1 cells and the upstream PPARgamma regulator, CCAAT-enhancer-binding protein beta. Furthermore, lecithin induced lipid accumulation in human hepatoma HepG2 cells. Our data suggest that lecithin is involved in adipogenesis, lipogenesis and hepatic lipid accumulation and it is implicated in obesity and hepatic steatosis.
 ...
PMID:Lecithin promotes adipocyte differentiation and hepatic lipid accumulation. 1928 19

Fatty acids stimulate lipid accumulation in parallel with increased expression of adipose differentiation-related protein (ADRP) in liver cells. Although it is generally considered that the fatty acid effect on ADRP expression is mediated by peroxisome proliferator-activated receptors (PPARs), we identified here an additional molecular mechanism using the NMuLi mouse liver nonparenchymal cell line, which expresses PPARgamma and delta but not alpha. Oleic acid (OA) and specific ligands for PPARgamma and -delta stimulated ADRP expression as well as the -2,090-bp ADRP promoter activity which encompasses the PPAR response element (PPRE) adjacent to an Ets/activator protein (AP)-1 site. When the AP-1 site was mutated, OA failed to stimulate the activity despite the presence of the PPRE, whereas ligands for PPARgamma and -delta did stimulate it and so did a PPARalpha ligand under the coexpression of PPARalpha. DNA binding of AP-1 was stimulated by OA but not by PPAR ligands. Because we previously demonstrated that Pycnogenol (PYC), a French maritime pine bark extract, suppressed ADRP expression in macrophages partly by suppression of AP-1 activity, we tested the effect of PYC on NMuLi cells. PYC reduced the OA-induced ADRP expression along with suppression of lipid droplet formation. However, PYC neither suppressed the OA-stimulated ADRP promoter activity nor DNA binding of AP-1 but, instead, reduced the ADRP mRNA half-life. All these results indicate that the effect of OA on ADRP expression requires AP-1 as well as PPRE, and PYC suppresses the ADRP expression in part by facilitating mRNA degradation. PYC, a widely used dietary supplement, could be beneficial for the prevention of excessive lipid accumulation such as hepatic steatosis.
 ...
PMID:Oleic acid-induced ADRP expression requires both AP-1 and PPAR response elements, and is reduced by Pycnogenol through mRNA degradation in NMuLi liver cells. 1938 73

The liver plays a central role in whole-body lipid metabolism by governing the synthesis, oxidization, transport and excretion of lipids. The unfolded protein response (UPR) was identified as a signal transduction system that is activated by ER stress. Recent studies revealed a critical role of the UPR in hepatic lipid metabolism. The IRE1/XBP1 branch of the UPR is activated by high dietary carbohydrates and controls the expression of genes involved in fatty acid and cholesterol biosynthesis. PERK mediated eIF2alpha phosphorylation is also required for the expression of lipogenic genes and the development of hepatic steatosis, likely by activating C/EBP and PPARgamma transcription factors. Further studies to define the molecular pathways that lead to the activation of the UPR by nutritional cues in the liver, and their contribution to human metabolic disorders such as hepatic steatosis, atherosclerosis and type 2 diabetes that are associated with dysregulation of lipid homeostasis, are warranted.
 ...
PMID:Intersection of the unfolded protein response and hepatic lipid metabolism. 1946 85


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>