From Scarcity to Solutions : Therapeutic Strategies to Restore Adipose Tissue Functionality in Rare Disorders of Lipodystrophy

Acknowledgements The authors would like to acknowledge funding provided by Diabetes UK (RD Lawrence Fellowship, 21/0006280) to G.D.M and the University of Aberdeen Doctoral Training Grant to M.T. The manuscript figure was created with BioRender.com.Peer reviewedPostprin

Ablation of Bscl2/Seipin in hepatocytes does not cause metabolic dysfunction in congenital generalised lipodystrophy

Funding Work was supported by the Medical Research Council (GDM/JJR; MR/L002620/1, MC/PC/15077), the Biotechnology and Biological Sciences Research Council (JJR; BB/K017772/1), Diabetes UK (GDM/JJR; 18/0005884), the British Heart Foundation (MD;PG/14/43/30889) and the Wellcome Trust and the University of Aberdeen ISSF Fund (GDM; ISSF Fellowship Support Fund).Peer reviewedPublisher PD

Gene therapy restores adipose tissue and metabolic health in a pre-clinical mouse model of lipodystrophy

The authors are extremely grateful to Dr Donna MacCallum (University of Aberdeen) for assistance with AAV vector i.v. tail vein injections and Pat Bain (University of Aberdeen) for design and generation of the graphical abstract. The authors would also like to thank the staff at the University of Aberdeen’s Microscopy and Histology Core Facility and the Medical Research Facility for support with animal breeding and maintenance. This research was supported by funding from the EFSD/Lilly Young Investigator Research Award Programme, Wellcome Trust ISSF Fellowship Support Fund, and Diabetes UK RD Lawrence Fellowship (21/0006280) awarded to G.D.M. and Diabetes UK (18/0005884) awarded to J.J.R.Peer reviewedPublisher PD

Fenretinide Treatment Prevents Diet-Induced Obesity in Association With Major Alterations in Retinoid Homeostatic Gene Expression in Adipose, Liver and Hypothalamus

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Bscl2 Deficiency Does Not Directly Impair the Innate Immune Response in a Murine Model of Generalized Lipodystrophy

Funding: Work was supported by Diabetes UK (JJR;18/0005884, MD;17/0005621) the Medical Research Council (JJR; MR/L002620/1, MC/PC/15077), the British Heart Foundation (MD; PG/14/43/30889), The Agency for Science, Technology and Research, Singapore (A*STAR) (WH), The Wellcome Trust (ISSF Funding to GDM) and the European Union’s Horizon 2020 ERC consolidator award (MB:2016-726152-TYPHI).Peer reviewedPublisher PD

Fenretinide mediated retinoic acid receptor signalling and inhibition of ceramide biosynthesis regulates adipogenesis, lipid accumulation, mitochondrial function and nutrient stress signalling in adipocytes and adipose tissue

Fenretinide (FEN) is a synthetic retinoid that inhibits obesity and insulin resistance in high-fat diet (HFD)-fed mice and completely prevents 3T3-L1 pre-adipocyte differentiation. The aim of this study was to determine the mechanism(s) of FEN action in 3T3-L1 adipocytes and in mice. We used the 3T3-L1 model of adipogenesis, fully differentiated 3T3-L1 adipocytes and adipose tissue from HFD-induced obese mice to investigate the mechanisms of FEN action. We measured expression of adipogenic and retinoid genes by qPCR and activation of nutrient-signalling pathways by western blotting. Global lipid and metabolite analysis was performed and specific ceramide lipid species measured by liquid chromatography-mass spectrometry. We provide direct evidence that FEN inhibits 3T3-L1 adipogenesis via RA-receptor (RAR)-dependent signaling. However, RARα antagonism did not prevent FEN-induced decreases in lipid levels in mature 3T3-L1 adipocytes, suggesting an RAR-independent mechanism. Lipidomics analysis revealed that FEN increased dihydroceramide lipid species 5- to 16-fold in adipocytes, indicating an inhibition of the final step of ceramide biosynthesis. A similar blockade in adipose tissue from FEN-treated obese mice was associated with a complete normalisation of impaired mitochondrial β-oxidation and tricarboxylic acid cycle flux. The FEN catabolite, 4-oxo-N-(4-hydroxyphenyl)retinamide (4-OXO), also decreased lipid accumulation without affecting adipogenesis. FEN and 4-OXO (but not RA) treatment additionally led to the activation of p38-MAPK, peIF2α and autophagy markers in adipocytes. Overall our data reveals FEN utilises both RAR-dependent and -independent pathways to regulate adipocyte biology, both of which may be required for FEN to prevent obesity and insulin resistance in vivo

Oligomers of the lipodystrophy protein seipin may co-ordinate GPAT3 and AGPAT2 enzymes to facilitate adipocyte differentiation

Abstract: Seipin deficiency causes severe congenital generalized lipodystrophy (CGL) and metabolic disease. However, how seipin regulates adipocyte development and function remains incompletely understood. We previously showed that seipin acts as a scaffold protein for AGPAT2, whose disruption also causes CGL. More recently, seipin has been reported to promote adipogenesis by directly inhibiting GPAT3, leading to the suggestion that GPAT inhibitors could offer novel treatments for CGL. Here we investigated the interactions between seipin, GPAT3 and AGPAT2. We reveal that seipin and GPAT3 associate via direct interaction and that seipin can simultaneously bind GPAT3 and AGPAT2. Inhibiting the expression of seipin, AGPAT2 or GPAT3 led to impaired induction of early markers of adipocyte differentiation in cultured cells. However, consistent with normal adipose mass in GPAT3-null mice, GPAT3 inhibition did not prevent the formation of mature adipocytes. Nonetheless, loss of GPAT3 in seipin-deficient preadipocytes exacerbated the failure of adipogenesis in these cells. Thus, our data indicate that GPAT3 plays a modest positive role in adipogenesis and argue against the potential of GPAT inhibitors to rescue white adipose tissue mass in CGL2. Overall, our study reveals novel mechanistic insights regarding the molecular pathogenesis of severe lipodystrophy caused by mutations in either seipin or AGPAT2

Adipocyte-specific protein tyrosine phosphatase 1B deletion increases lipogenesis, adipocyte cell size and is a minor regulator of glucose homeostasis

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A systematic review and consensus definitions for standardised end-points in perioperative medicine: pulmonary complications

BackgroundThere is a need for robust, clearly defined, patient-relevant outcome measures for use in randomised trials in perioperative medicine. Our objective was to establish standard outcome measures for postoperative pulmonary complications research