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)

Adipose differentiation-related protein (ADFP; also known as ADRP or adipophilin), is a lipid droplet (LD) protein found in most cells and tissues. ADFP expression is strongly induced in cells with increased lipid load. We have inactivated the Adfp gene in mice to better understand its role in lipid accumulation. The Adfp-deficient mice have unaltered adipose differentiation or lipolysis in vitro or in vivo. Importantly, they display a 60% reduction in hepatic triglyceride (TG) and are resistant to diet-induced fatty liver. To determine the mechanism for the reduced hepatic TG content, we measured hepatic lipogenesis, very-low-density lipoprotein (VLDL) secretion, and lipid uptake and utilization, all of which parameters were shown to be similar between mutant and wild-type mice. The finding of similar VLDL output in the presence of a reduction in total TG in the Adfp-deficient liver is explained by the retention of TG in the microsomes where VLDL is assembled. Given that lipid droplets are thought to form from the outer leaflet of the microsomal membrane, the reduction of TG in the cytosol with concomitant accumulation of TG in the microsome of Adfp-/- cells suggests that ADFP may facilitate the formation of new LDs. In the absence of ADFP, impairment of LD formation is associated with the accumulation of microsomal TG but a reduction in TG in other subcellular compartments.
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PMID:Protection against fatty liver but normal adipogenesis in mice lacking adipose differentiation-related protein. 1642 58

Intracellular lipid droplets are associated with a myriad of afflictions including obesity, fatty liver disease, coronary artery disease, and infectious diseases (eg, HCV and tuberculosis). To develop high-content analysis (HCA) techniques to analyze lipid droplets and associated proteins, primary human preadipocytes were plated in 96-well dishes in the presence of rosiglitazone (rosi), a PPAR-(c) agonist that promotes adipogenesis. The cells were then labeled for nuclei, lipid droplets, and proteins such as perilipin, protein kinase C (PKC), and hormone-sensitive lipase (HSL). The cells were imaged via automated digital microscopy and algorithms were developed to quantify lipid droplet (Lipid Droplet algorithm) and protein expression and colocalization (Colocalization algorithm). The algorithms, which were incorporated into Vala Science Inc's CyteSeer((R)) image cytometry program, quantified the rosi-induced increases in lipid droplet number, size, and intensity, and the expression of perilipin with exceptional consistency (Z' values of 0.54-0.71). Regarding colocalization with lipid droplets, Pearson's correlation coefficients of 0.38 (highly colocalized), 0.16 (moderate), and -0.0010 (random) were found for perilipin, PKC, and HSL, respectively. For hepatocytes (AML12, HuH-7, and primary cells), the algorithms also quantified the stimulatory and inhibitory effect of oleic acid and triacsin C on lipid droplets (Z's > 0.50) and ADFP expression/colocalization. Oleic acid-induced lipid droplets in HeLa cells and macrophages (THP-1) were also well quantified. The results suggest that HCA techniques can be utilized to quantify lipid droplets and associated proteins in many cell models relevant to a variety of diseases.
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PMID:Quantification of lipid droplets and associated proteins in cellular models of obesity via high-content/high-throughput microscopy and automated image analysis. 1989 45

We previously showed that adipose differentiation related protein (Adfp)-deficient mice display a 60% reduction in hepatic triglyceride (TG) content. In this study, we investigated the role of ADFP in lipid and glucose homeostasis in a genetic obesity model, Lep(ob/ob) mice. We bred Adfp(-/-) mice with Lep(ob/ob) mice to create Lep(ob/ob)/Adfp(-/-) and Lep(ob/ob)/Adfp(+/+) mice and analyzed the hepatic lipids, lipid droplet (LD) morphology, LD protein composition and distribution, lipogenic gene expression, and VLDL secretion, as well as insulin sensitivity of the two groups of mice. Compared with Lep(ob/ob)/Adfp(+/+) mice, Lep(ob/ob)/Adfp(-/-) mice displayed an increased VLDL secretion rate, a 25% reduction in hepatic TG associated with improvement in fatty liver grossly and microscopically with a change of the size of LDs in a proportion of the hepatocytes and a redistribution of major LD-associated proteins from the cytoplasmic compartment to the LD surface. There was no detectable change in lipogenic gene expression. Lep(ob/ob)/Adfp(-/-) mice also had improved glucose tolerance and insulin sensitivity in both liver and muscle. The alteration of LD size in the liver of Lep(ob/ob)/Adfp(-/-) mice despite the relocation of other LDPs to the LD indicates a nonredundant role for ADFP in determining the size and distribution of hepatic LDs.
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PMID:Absence of adipose differentiation related protein upregulates hepatic VLDL secretion, relieves hepatosteatosis, and improves whole body insulin resistance in leptin-deficient mice. 2042 69

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease, characterized by the excess accumulation of lipids in the liver. It has been demonstrated that the dysregulation of lipid droplet (LD)-associated proteins may be involved in the development of NAFLD. Adipose differentiation-related protein (ADRP), as one of the major LD-associated proteins, is expressed in normal and steatotic livers; however, the exact role of ADRP in the liver remains unknown. Previous studies have indicated that metformin, as an antidiabetic drug, effectively ameliorates NAFLD. However, its cellular and molecular mechanisms of action remain to be elucidated. Therefore, the aim of this study was to determine the role of ADRP in the metformin-mediated regulation of hepatic steatosis. We examined the effects of meformin in vivo and in vitro using ob/ob mice and primary hepatocytes, respectively. Lipid accumulation in the hepatocytes was induced by treatment with oleate. Our results revealed that metformin prevented hepatic steatosis in ob/ob mice and inhibited oleate-induced lipid accumulation in primary hepatocytes. Furthermore, using real-time PCR and western blot analysis, we examined the mRNA and protein expression of ADRP, respectively. We found that metformin significantly decreased the expression levels of ADRP. In addition, to further clarify the role of ADRP in lipid accumulation, we generated recombinant adenoviruses to induce the overexpression of ADRP and to knockdown ADRP. In the hepatocytes in which ADRP was overexpressed, the reducing effects of metformin on lipid accumulation were diminished. However, the knockdown of ADRP using siRNA targeting ADRP reduced the accumulation of triglycerides. Taken together, our data demonstrate that metformin prevents hepatic steatosis by regulating the expression of ADRP, which may be a key target in the treatment of NAFLD.
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PMID:Metformin prevents hepatic steatosis by regulating the expression of adipose differentiation-related protein. 2425 18