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Pelosi M, Testet E, Le Lay S, Dugail I, Tang X, Mabilleau G, Hamel Y, Madrange M, Blanc T, Odent T, McMullen TPW, Alfò M, Brindley DN, de Lonlay P. Normal human adipose tissue functions and differentiation in patients with biallelic LPIN1 inactivating mutations. J Lipid Res 2017; 58:2348-2364. [PMID: 28986436 PMCID: PMC5711497 DOI: 10.1194/jlr.p075440] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 08/23/2017] [Indexed: 12/22/2022] Open
Abstract
Lipin-1 is a Mg2+-dependent phosphatidic acid phosphatase (PAP) that in mice is necessary for normal glycerolipid biosynthesis, controlling adipocyte metabolism, and adipogenic differentiation. Mice carrying inactivating mutations in the Lpin1 gene display the characteristic features of human familial lipodystrophy. Very little is known about the roles of lipin-1 in human adipocyte physiology. Apparently, fat distribution and weight is normal in humans carrying LPIN1 inactivating mutations, but a detailed analysis of adipose tissue appearance and functions in these patients has not been available so far. In this study, we performed a systematic histopathological, biochemical, and gene expression analysis of adipose tissue biopsies from human patients harboring LPIN1 biallelic inactivating mutations and affected by recurrent episodes of severe rhabdomyolysis. We also explored the adipogenic differentiation potential of human mesenchymal cell populations derived from lipin-1 defective patients. White adipose tissue from human LPIN1 mutant patients displayed a dramatic decrease in lipin-1 protein levels and PAP activity, with a concomitant moderate reduction of adipocyte size. Nevertheless, the adipose tissue develops without obvious histological signs of lipodystrophy and with normal qualitative composition of storage lipids. The increased expression of key adipogenic determinants such as SREBP1, PPARG, and PGC1A shows that specific compensatory phenomena can be activated in vivo in human adipocytes with deficiency of functional lipin-1.
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Affiliation(s)
- Michele Pelosi
- Centre de Référence des Maladies Héréditaires du Métabolisme, Institut Imagine des Maladies Génétiques, Laboratoire de génétique des maladies autoinflammatoires monogéniques, INSERM UMR1163, Université Paris Descartes et Hôpital Necker-Enfants malades (Assistance publique - Hôpitaux de Paris), Paris, France
| | - Eric Testet
- Laboratoire de Biogenèse Membranaire-UMR 5200, CNRS, Université de Bordeaux, Villenave d'Ornon, France
| | - Soazig Le Lay
- INSERM, UMR1063, Université d'Angers, UBL, Angers, France
| | - Isabelle Dugail
- INSERM, U1166, Equipe 6, Université Pierre et Marie Curie, Paris, France
| | - Xiaoyun Tang
- Department of Biochemistry, Signal Transduction Research Group, University of Alberta, Edmonton, Alberta, Canada
| | | | - Yamina Hamel
- Centre de Référence des Maladies Héréditaires du Métabolisme, Institut Imagine des Maladies Génétiques, Laboratoire de génétique des maladies autoinflammatoires monogéniques, INSERM UMR1163, Université Paris Descartes et Hôpital Necker-Enfants malades (Assistance publique - Hôpitaux de Paris), Paris, France
| | - Marine Madrange
- Centre de Référence des Maladies Héréditaires du Métabolisme, Institut Imagine des Maladies Génétiques, Laboratoire de génétique des maladies autoinflammatoires monogéniques, INSERM UMR1163, Université Paris Descartes et Hôpital Necker-Enfants malades (Assistance publique - Hôpitaux de Paris), Paris, France
| | - Thomas Blanc
- Department of Pediatric Surgery and Urology, Hôpital Necker-Enfants malades-Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Thierry Odent
- Department of Pediatric Orthopedics, Hôpital Necker-Enfants malades-Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Todd P W McMullen
- Department of Surgery, University of Alberta, Edmonton, Alberta, Canada
| | - Marco Alfò
- Dipartimento di Scienze Statistiche, Sapienza Università di Roma, Rome, Italy
| | - David N Brindley
- Department of Biochemistry, Signal Transduction Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Pascale de Lonlay
- Centre de Référence des Maladies Héréditaires du Métabolisme, Institut Imagine des Maladies Génétiques, Laboratoire de génétique des maladies autoinflammatoires monogéniques, INSERM UMR1163, Université Paris Descartes et Hôpital Necker-Enfants malades (Assistance publique - Hôpitaux de Paris), Paris, France
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Massarweh A, Bosco M, Iatmanen-Harbi S, Tessier C, Amana L, Busca P, Chantret I, Gravier-Pelletier C, Moore SEH. Brefeldin A promotes the appearance of oligosaccharyl phosphates derived from Glc3Man9GlcNAc2-PP-dolichol within the endomembrane system of HepG2 cells. J Lipid Res 2016; 57:1477-91. [PMID: 27281477 DOI: 10.1194/jlr.m068551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Indexed: 01/04/2023] Open
Abstract
We reported an oligosaccharide diphosphodolichol (DLO) diphosphatase (DLODP) that generates dolichyl-phosphate and oligosaccharyl phosphates (OSPs) from DLO in vitro. This enzyme could underlie cytoplasmic OSP generation and promote dolichyl-phosphate recycling from truncated endoplasmic reticulum (ER)-generated DLO intermediates. However, during subcellular fractionation, DLODP distribution is closer to that of a Golgi apparatus (GA) marker than those of ER markers. Here, we examined the effect of brefeldin A (BFA), which fuses the GA with the ER on OSP metabolism. In order to increase the steady state level of truncated DLO while allowing formation of mature DLO (Glc3Man9GlcNAc2-PP-dolichol), dolichyl-P-mannose Man7GlcNAc2-PP-dolichol mannosyltransferase was partially downregulated in HepG2 cells. We show that BFA provokes GA endomannosidase trimming of Glc3Man9GlcNAc2-PP-dolichol to yield a Man8GlcNAc2-PP-dolichol structure that does not give rise to cytoplasmic Man8GlcNAc2-P. BFA also strikingly increased OSP derived from mature DLO within the endomembrane system without affecting levels of Man7GlcNAc2-PP-dolichol or cytoplasmic Man7GlcNAc2-P. The BFA-provoked increase in endomembrane-situated OSP is sensitive to nocodazole, and BFA causes partial redistribution of DLODP activity from GA- to ER-containing regions of density gradients. These findings are consistent with BFA-provoked microtubule-dependent GA-to-ER transport of a previously reported DLODP that acts to generate a novel endomembrane-situated OSP population.
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Affiliation(s)
- Ahmad Massarweh
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France Université Pierre et Marie Curie, Paris 6, Paris, France
| | - Michaël Bosco
- Université Paris Descartes, CICB-Paris, CNRS UMR8601, LCBPT, Paris, France
| | | | - Clarice Tessier
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France
| | - Laura Amana
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France
| | - Patricia Busca
- Université Paris Descartes, CICB-Paris, CNRS UMR8601, LCBPT, Paris, France
| | - Isabelle Chantret
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France
| | | | - Stuart E H Moore
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France
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Abstract
Signaling through the phosphoinositide 3-kinase pathways mediates the actions of a plethora of hormones, growth factors, cytokines, and neurotransmitters upon their target cells following receptor occupation. Overactivation of these pathways has been implicated in a number of pathologies, in particular a range of malignancies. The tight regulation of signaling pathways necessitates the involvement of both stimulatory and terminating enzymes; inappropriate activation of a pathway can thus result from activation or inhibition of the two signaling arms. The focus of this review is to discuss, in detail, the activities of the identified families of phosphoinositide phosphatase expressed in humans, and how they regulate the levels of phosphoinositides implicated in promoting malignancy.
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Affiliation(s)
- Simon A Rudge
- Signalling Programme, Babraham Institute, Cambridge CB22 3AT, United Kingdom
| | - Michael J O Wakelam
- Signalling Programme, Babraham Institute, Cambridge CB22 3AT, United Kingdom
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