scholarly journals Direct interaction of Plin2 with lipids on the surface of lipid droplets: a live cell FRET analysis

2012 ◽  
Vol 303 (7) ◽  
pp. C728-C742 ◽  
Author(s):  
Avery L. McIntosh ◽  
Subramanian Senthivinayagam ◽  
Kenneth C. Moon ◽  
Shipra Gupta ◽  
Joel S. Lwande ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Cholesteryl Ester ◽  
Lipid Droplet ◽  
Lipid Droplets ◽  
Nile Red ◽  
Direct Interaction ◽  
Structure And Function ◽  
Live Cell ◽  
High Yield ◽  
And Function

Despite increasing awareness of the health risks associated with excess lipid storage in cells and tissues, knowledge of events governing lipid exchange at the surface of lipid droplets remains unclear. To address this issue, fluorescence resonance energy transfer (FRET) was performed to examine live cell interactions of Plin2 with lipids involved in maintaining lipid droplet structure and function. FRET efficiencies ( E) between CFP-labeled Plin2 and fluorescently labeled phosphatidylcholine, sphingomyelin, stearic acid, and cholesterol were quantitated on a pixel-by-pixel basis to generate FRET image maps that specified areas with high E (>60%) in lipid droplets. The mean E and the distance R between the probes indicated a high yield of energy transfer and demonstrated molecular distances on the order of 44–57 Å, in keeping with direct molecular contact. In contrast, FRET between CFP-Plin2 and Nile red was not detected, indicating that the CFP-Plin2/Nile red interaction was beyond FRET proximity (>100 Å). An examination of the effect of Plin2 on cellular metabolism revealed that triacylglycerol, fatty acid, and cholesteryl ester content increased while diacylglycerol remained constant in CFP-Plin2-overexpressing cells. Total phospholipids also increased, reflecting increased phosphatidylcholine and sphingomyelin. Consistent with these results, expression levels of enzymes involved in triacylglycerol, cholesteryl ester, and phospholipid synthesis were significantly upregulated in CFP-Plin2-expressing cells while those associated with lipolysis either decreased or were unaffected. Taken together, these data show for the first time that Plin2 interacts directly with lipids on the surface of lipid droplets and influences levels of key enzymes and lipids involved in maintaining lipid droplet structure and function.

Structure and Function of Cholesteryl Ester Transfer Protein in the Tree Shrew

Lipids ◽  
2011 ◽  
Vol 46 (7) ◽  
pp. 607-616
Author(s):  
Huirong Liu ◽  
Gang Wu ◽  
Bing Zhou ◽  
Baosheng Chen
Keyword(s):  
Cholesteryl Ester ◽  
Cholesteryl Ester Transfer Protein ◽  
Tree Shrew ◽  
Structure And Function ◽  
Transfer Protein ◽  
And Function

scholarly journals Hepatic stellate cells in the liver of dogs with steroid-induced hepatopathy

2014 ◽  
Vol 58 (2) ◽  
pp. 273-276
Author(s):  
Małgorzata Sobczak-Filipiak ◽  
Józef Szarek ◽  
Michał Czopowicz ◽  
Joanna Mieczkowska ◽  
Roman Lechowski
Keyword(s):  
Electron Microscope ◽  
Hepatic Stellate Cells ◽  
Lipid Droplets ◽  
Stellate Cells ◽  
Structure And Function ◽  
Surgical Biopsy ◽  
Carnoy’S Solution ◽  
Short Period ◽  
Collagen Accumulation ◽  
And Function

Abstract Morphological lesions in hepatic stellate cells caused by the immunosuppressive doses of dexamethasone were investigated in dogs. The archival samples of liver collected during a surgical biopsy were examined. The samples were fixed in 10% buffered formalin or Carnoy’s solution and then stained with routine histochemical methods. The lesions were also investigated under electron microscope. It was demonstrated that the number of stellate cells significantly increased (P = 0.0277), yet the size of cytoplasmic lipid droplets significantly decreased (P = 0.0001). Even though steroid-induced hepatopathy is considered to be a reversible pathology, and the lesions in hepatocytes under the influence of dexamethasone occur in a short period, it was found that hepatic stellate cells proliferated and underwent activation. This resulted in collagen accumulation in the hepatic sinuses. The functional and morphological disturbances in the canine liver in the course of steroid-induced hepatopathy are initially subclinical, but the changes in the structure and function of hepatic stellate cells may become a cause of lesions in the wall of hepatic sinusoidal vessels, which may induce additional functional pathologies unrelated to the damage to hepatocytes.

scholarly journals RNA-Selective, Live Cell Imaging Probes for Studying Nuclear Structure and Function

2006 ◽  
Vol 13 (6) ◽  
pp. 615-623 ◽  
Author(s):  
Qian Li ◽  
Yunkyung Kim ◽  
Joshua Namm ◽  
Amita Kulkarni ◽  
Gus R. Rosania ◽  
...  
Keyword(s):  
Nuclear Structure ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Structure And Function ◽  
Live Cell ◽  
Imaging Probes ◽  
And Function

Pulmonary abnormalities due to ABCA1 deficiency in mice

2005 ◽  
Vol 289 (6) ◽  
pp. L980-L989 ◽  
Author(s):  
Sandra R. Bates ◽  
Jian-Qin Tao ◽  
Heidi L. Collins ◽  
Omar L. Francone ◽  
George H. Rothblat
Keyword(s):  
Cholesteryl Ester ◽  
Free Cholesterol ◽  
Lipid Analysis ◽  
Total Phospholipid ◽  
Density Lipoprotein ◽  
Structure And Function ◽  
Normal Lung ◽  
Mouse Lung ◽  
Alveolar Proteinosis ◽  
And Function

Mice gene targeted for ATP-binding cassette transporter A1 (ABCA1; Abca1−/−) have been shown to have low-serum high-density lipoprotein and abnormal lung morphology. We examined alterations in the structure and function of lungs from −/− mice (DBA1/J). Electron microscopy of the diseased mouse lung revealed areas of focal disease confirming previous results ( 47 ). Lipid analysis of the lung tissue of −/− mice showed a 1.2- and 1.4-fold elevation in total phospholipid (PL) and saturated phosphatidylcholine, respectively, and a marked 50% enrichment in total cholesterol content predominately due to a 17.5-fold increase in cholesteryl ester compared with wild type (WT). Lung surfactant in the −/− mice was characterized by alveolar proteinosis (161%), a slight increase in total PL (124%), and a marked increase in free cholesterol (155%) compared with WT. Alveolar macrophages were enriched in cholesterol (4.8-fold) due to elevations in free cholesterol (2.4-fold) and in cholesteryl ester (14.8-fold) compared with WT macrophages. More PL mass was cleared from the alveolar space of −/− mice lungs, measured using intratracheal installation of 3H-PL liposomes. Compared with WT mice, the Abca1−/− mice demonstrated respiratory distress with rapid, shallow breathing. Thus the lungs of mice lacking ABCA1 protein demonstrated abnormal morphology and physiology, with alveolar proteinosis and cholesterol enrichment of tissue, surfactant, and macrophages. The results indicate that the activity of ABCA1 is important for the maintenance of normal lung lipid composition, structure, and function.

91 A NOVEL TECHNIQUE FOR EVALUATION OF THE LIPID CONTENT IN PIG EMBRYOS

2008 ◽  
Vol 20 (1) ◽  
pp. 126 ◽  
Author(s):  
M. Romek ◽  
B. Gajda ◽  
E. Krzysztofowicz ◽  
Z. Smorag
Keyword(s):  
Lipid Droplet ◽  
Lipid Content ◽  
Lipid Droplets ◽  
Nile Red ◽  
Total Lipid Content ◽  
Volume Density ◽  
Molecular Probes ◽  
New Method ◽  
Stages Of Development

A high level of lipids, mainly triglycerides and fatty acids, present in embryo cells in the form of lipid droplets is the major factor associated with low cryopreservation of porcine embryos. Previous results demonstrated that the low tolerance of pig embryos to cryopreservation can be increased through reduction of lipid droplet contents. Therefore, in order to improve cryopreservation techniques of porcine embryos, it is fundamental to establish proper culture conditions which ultimately will enable a decrease in lipid content. Unfortunately, there are no precise and efficient methods to evaluate the lipid contents of single pig embryos. Previously used stereological analysis combined with physical serial sectioning (Romek et al. 2007 Reprod. Domest. Anim. in press) is time-consuming, and measurement of triglyceride levels based on enzymatic hydrolysis eliminates other types of lipids from the analysis. Taking the above problems into account, we have developed a new method for evaluation of total lipid content in pig embryos. It is based on visualization of lipid droplets using the specific fluorescent dye Nile red and applying confocal scanning microscopy followed by the Cavalieri method. This method enables measurement of several stereological parameters, especially the volume density of lipid droplets per unit volume of cytoplasm Vv(fat,c), which quantifies most precisely the amount of intracellular lipid. The experiment was carried out on 2- to 4-cell and 8- to 16-cell pig embryos, morulae, blastocysts, and late blastocysts cultured in vitro. Embryos were developed from in vivo-produced zygotes to appropriate stages of development in North Carolina State University (NCSU) 23 medium. For each stage, ten of the embryos were examined. Embryos were denuded and fixed with 2% glutaraldehyde and 2% formaldehyde, stained with 100 nm Nile red (Molecular Probes, Leiden, The Netherlands), and analyzed by means of a confocal microscope LSM 510 Meta (Carl Zeiss MicroImaging GmbH, G�ttingen, Germany). Serial optical sections of each individual embryo were measured by the point counting method, and then the Cavalieri method was used to estimate Vv(fat,). Vv(fat,c) values calculated for embryos at different stages of development were compared by one-way analysis of variance and Tukey's intervals. For cultured pig embryos, volume density of lipid droplets Vv(fat,c) significantly decreased during cleavage from 0.55 µm3 µm–3 at the 2- to 4-cell-embryo stage to 0.46 µm3 µm–3 at the blastocyst stage. The differences between lipid droplet volumes calculated for morulae, blastocysts, and late blastocysts were statistically significant. In conclusion, our new method is more precise, efficient, and quick in comparison to previously used ones. Moreover, we confirmed that the content of total lipids in cultured pig embryo is reduced during its development. This research was funded by the State Committee for Scientific Research (Project No. 2 P06D 003 26) and Net of Reproduction Biotechnology.

scholarly journals An Overview of Lipid Droplets in Cancer and Cancer Stem Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
L. Tirinato ◽  
F. Pagliari ◽  
T. Limongi ◽  
M. Marini ◽  
A. Falqui ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cancer Stem Cells ◽  
Lipid Composition ◽  
Lipid Droplets ◽  
Active Sites ◽  
Structure And Function ◽  
Key Players ◽  
And Function ◽  
And Storage ◽  
Cellular Organelles

For decades, lipid droplets have been considered as the main cellular organelles involved in the fat storage, because of their lipid composition. However, in recent years, some new and totally unexpected roles have been discovered for them: (i) they are active sites for synthesis and storage of inflammatory mediators, and (ii) they are key players in cancer cells and tissues, especially in cancer stem cells. In this review, we summarize the main concepts related to the lipid droplet structure and function and their involvement in inflammatory and cancer processes.

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