Induced translocation of glycosylphosphatidylinositol‐anchored proteins from lipid droplets to adiposomes in rat adipocytes

Müller, Günter; Jung, Christian; Wied, Susanne; Biemer‐Daub, Gabriele

doi:10.1111/j.1476-5381.2009.00360.x

Cited by 31 publications

(39 citation statements)

References 71 publications

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“…Previous studies have identified exosomes in the culture supernatant of mouse adipose tissues (Deng et al, 2009), rat primary adipocytes (Müller et al, 2009a;Müller et al, 2009b;Müller et al, 2011), and mouse adipocyte cell line 3T3-L1 (Ogawa et al, 2010;Sano et al, 2014). Deng et al (2009) to lipogenesis and promote lipid accumulation in recipient 3T3-L1 adipocytes (Sano et al, 2014).…”

Section: Aim Of Studymentioning

confidence: 99%

Adiponectin is partially associated with exosomes in mouse serum

Phoonsawat

Aoki-Yoshida

Tsuruta

et al. 2014

Biochemical and Biophysical Research Communications

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Previous studies suggest that adipocyte-derived exosomes play a role in cell-to-cell communication during the development of metabolic diseases. However, the characteristics and function of exosomes released from adipocytes in vivo remain to be elucidated. Clearly, exosomes released from adipocytes could exist in the circulation. In addition, because the composition of exosomes is heterogenic, depending on the cellular origin of the exosome, adipocyte-derived exosomes could be accompanied by molecules produced specifically in adipocytes. In this context, this study postulated that such molecules associated with exosomes in the serum could be markers for adipocyte-derived exosomes in vivo. This study particularly focused on secretory proteins produced specifically in adipocytes, namely adipocytokines including adiponectin, leptin, and resistin. Serum adiponectin is partially associated with exosomesBased on western blotting, CD63, a well-known protein marker of exosomes, was concentrated in the pellet of mouse serum after ultracentrifugation, suggesting successful isolation of exosomes. Western blotting detected adiponectin but no leptin and only trace amounts of resistin in the exosome fraction. After ultracentrifugation on a discontinuous gradient, both adiponectin and CD63 were detected in a fraction at a density of 1.17 g/mL, consistent with the density of exosomes. The adiponectin signal in the exosome fraction was decreased by proteinase K treatment and completely quenched by a combination of proteinase K and Triton X-100. These results suggest that a portion of adiponectin exists as a transmembrane protein in the exosomes in mouse serum. showed that the concentration of adiponectin in the serum and the ratio of adiponectin to total protein in the exosome fraction were lower in obese mice than in lean mice.In conclusion, this study showed that serum adiponectin is partially associated with exosomes in mice. Considering that adiponectin is produced exclusively by adipocytes, adiponectin-associated exosomes in serum could be derived from adipocytes. This study proposes that adiponectin could be a marker for exosomes released from adipocytes in vivo.iii

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Section: Aim Of Studymentioning

confidence: 99%

Adiponectin is partially associated with exosomes in mouse serum

Phoonsawat

Aoki-Yoshida

Tsuruta

et al. 2014

Biochemical and Biophysical Research Communications

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“…Published procedures were used for the preparation of LD and DIGs (from 2.5 × 10 6 cells per incubation; Müller et al, 2002;2008a, d), determination of 5′-nucleotidase activity (Müller et al, 2008d), isoproterenol-induced lipolysis with enzymic determination of the glycerol released (with 1.0 × 10 6 cells in 1 ml of incubation volume; Müller et al, 2003), fatty acid esterification as the incorporation of [1-14 C]palmitate into total acylglycerols (Müller et al, in press), protein concentration using the BCA method (Pierce) with BSA as calibration standard and PC content of ADIP (Müller et al, 2009a), sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE; 4-12% Bis-TRIS precast gel, pH 6.4, 4-morpholineethanesulfonic acid [MES]-SDS running buffer) under reducing conditions (Müller et al, 2008a), extraction and precipitation of proteins from LD, DIGs and incubation medium under native conditions (Müller et al, 2009b) and treatment of ADIP, DIGs, LD or incubation medium with alkaline Na 2 CO 3 , NaCl, detergents, free and cholesterol-bound methylβ-cyclodextrin (m-βCD), (glycosyl)phosphatidylinositol-specific phospholipase C (G)PI-PLC from Bacillus cereus or NaNO 2 (0.25 M, adjusted with sodium acetate to pH 4.0, 3 h at 25°C) (Müller et al, 1997b(Müller et al, , 2002(Müller et al, , 2009a. Concentration-response curves were fitted using the GraphPad Prism 4.03 software (GraphPad Software Inc., La Jolla, CA, USA).…”

Section: Miscellaneousmentioning

confidence: 99%

Inhibition of lipolysis by adiposomes containing glycosylphosphatidylinositol-anchored Gce1 protein in rat adipocytes

Müller

Wied

Jung

et al. 2010

Archives of Physiology and Biochemistry

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Small membrane vesicles released from large adipocytes and harbouring the glycosylphosphatidylinositol-anchored (GPI-) AMP-degrading protein CD73 have previously been demonstrated to stimulate the signal-induced esterification of free fatty acids into neutral lipids suggesting a role of these so-called adiposomes (ADIP) in the paracrine regulation of lipid metabolism in the adipose tissue. Here the involvement of another constituent GPI-protein of ADIP, the cAMP-degrading protein Gce1 in the signal-induced inhibition of lipolysis was investigated in primary rat adipocytes. Incubation of small, and to a lower degree, large adipocytes with ADIP inhibited lipolysis and increased its sensitivity toward inhibition by H(2)O(2), the anti-diabetic drug glimepiride and palmitate. This was accompanied by the transfer of Gce1 from the ADIP to detergent-insoluble glycolipid-enriched plasma membrane microdomains (DIGs) and its subsequent translocation to cytoplasmic lipid droplets (LD) of the acceptor adipocytes. The translocation from DIGs to LD rather than the transfer from ADIP to DIGs of Gce1 was stimulated by H(2)O(2) > glimepiride > palmitate. Both transfer and translocation led to salt- and carbonate-resistant association of Gce1 with DIGs and LD, respectively, and relied on the structural integrity of the DIGs and GPI anchor of Gce1. In conclusion, the trafficking of GPI-proteins from ADIP of donor adipocytes via DIGs to LD of acceptor adipocytes mediates paracrine regulation of lipolysis within adipose tissue.

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“…The GPI anchor of Gce1 and CD73 becomes embedded in the extracellular leaflet of the adiposomal phospholipid bilayer and the protein moieties exposed at the adiposomal surface [139,140] . These adiposomes resemble the well-characterized microvesicles and exosomes harbouring subsets of transmembrane [141][142][143] and GPI proteins [82,139,144] , which are released from most mammalian cells into the circulation in vivo or into the incubation medium in vitro. The release of microvesicles following plasma membrane blebbing or shedding as well as of exosomes following plasma membrane fusion, that is exocytosis, of so-called multivesicular bodies, which both presumably occur at plasma membrane DIGs [142][143][144][145][146][147][148][149][150][151][152][153][154][155][156] , is either constitutive [145] or upregulated by cellular activation or apoptosis [146][147][148] .…”

Section: Trafficking Of Gpi Proteins Between Adipocytesmentioning

confidence: 99%

Oral Protein Therapy for the Future – Transport of Glycolipid-Modified Proteins: Vision or Fiction

Müller¹

2010

Pharmacology

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The reliable and early diagnosis of common complex multifactorial diseases depends on the individual determination of all (or as many as possible) polymorphisms of each susceptibility gene together with amount and type of the corresponding gene products and their downstream effects, including the synthesis and flux of metabolites and regulation of signalling processes. In addition, this system’s biology-driven personalized diagnosis must be accompanied by options for personalized reliable and early therapy. In the mid-term, the direct substitution or inhibition of the proteins encoded by the corresponding defective gene products of the susceptibility genes exerting lower or higher activity by administration of the ‘normal’ proteins or inhibitory antibodies, respectively, seems to be most promising. The critical hurdle of oral bioavailability as well as transport into the cytoplasm of the target cells, if required, could be overcome by therapeutic proteins with carboxy-terminal modification by glycosylphosphatidylinositol (GPI). This may be deduced from recent experiments with rat adipocytes. Here this membrane-anchoring glycolipid structure induces the sequential transport of proteins from special regions of the plasma membrane via the surface of intracellular lipid droplets to special membrane vesicles, which are finally released from the adipocytes together with the associated GPI proteins. It remains to be studied whether similar molecular mechanisms operate in intestinal epithelial cells and may enable the transport of GPI proteins from the intestinal lumen into the blood stream. If so, modification of proteins encoded by (combinations of) susceptibility genes with GPI could significantly facilitate the personalized therapy of common diseases on the basis of ‘inborn’ safety, efficacy, rapid realization and oral application.

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Induced translocation of glycosylphosphatidylinositol‐anchored proteins from lipid droplets to adiposomes in rat adipocytes

Cited by 31 publications

References 71 publications

Adiponectin is partially associated with exosomes in mouse serum

Adiponectin is partially associated with exosomes in mouse serum

Inhibition of lipolysis by adiposomes containing glycosylphosphatidylinositol-anchored Gce1 protein in rat adipocytes

Oral Protein Therapy for the Future – Transport of Glycolipid-Modified Proteins: Vision or Fiction

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