Abstract
Objective
Mutations to the BSCL2 gene disrupt the protein seipin and cause the most severe form of congenital generalised lipodystrophy (CGL). Affected individuals exhibit a near complete loss of white adipose tissue (WAT) and suffer from metabolic disease. Seipin is critical for adipocyte development in culture and mice with germline disruption to Bscl2 recapitulate the effects of BSCL2 disruption in humans. Here we examined whether loss of Bscl2 specifically in developing adipocytes in vivo is sufficient to prevent adipose tissue development and cause all features observed with congenital BSCL2 disruption.
Methods
We generated and characterised a novel mouse model of Bscl2 deficiency in developing adipocytes (Ad-B2(-/-)) using the adipose-specific Adiponectin-Cre line.
Results
We demonstrate that Ad-B2(-/-) mice display early onset lipodystrophy, in common with congenital Bscl2 null mice and CGL2 patients. However, glucose intolerance, insulin resistance, and severe hepatic steatosis are not apparent. Food intake and energy expenditure are unchanged, but Ad-B2(-/-) mice exhibit significantly altered substrate utilisation. We also find differential effects of seipin loss between specific adipose depots revealing new insights regarding their varied characteristics. When fed a high-fat diet, Ad-B2(-/-) mice entirely fail to expand adipose mass but remain glucose tolerant.
Conclusions
Our findings demonstrate that disruption of Bscl2 specifically in developing adipocytes is sufficient to cause the early-onset generalised lipodystrophy observed in patients with mutations in BSCL2. However, this significant reduction in adipose mass does not cause the overt metabolic dysfunction seen in Bscl2 knockout mice, even following a high-fat diet challenge.
Mutations to the BSCL2 gene disrupt the protein seipin and cause the most severe form of congenital generalised lipodystrophy (CGL). Affected individuals exhibit a near complete loss of white adipose tissue (WAT) and suffer from metabolic disease. Seipin is critical for adipocyte development in culture and mice with germline disruption to Bscl2 recapitulate the effects of BSCL2 disruption in humans. Here we examined whether loss of Bscl2 specifically in developing adipocytes in vivo is sufficient to prevent adipose tissue development and cause all features observed with congenital BSCL2 disruption.
Methods
We generated and characterised a novel mouse model of Bscl2 deficiency in developing adipocytes (Ad-B2(-/-)) using the adipose-specific Adiponectin-Cre line.
Results
We demonstrate that Ad-B2(-/-) mice display early onset lipodystrophy, in common with congenital Bscl2 null mice and CGL2 patients. However, glucose intolerance, insulin resistance, and severe hepatic steatosis are not apparent. Food intake and energy expenditure are unchanged, but Ad-B2(-/-) mice exhibit significantly altered substrate utilisation. We also find differential effects of seipin loss between specific adipose depots revealing new insights regarding their varied characteristics. When fed a high-fat diet, Ad-B2(-/-) mice entirely fail to expand adipose mass but remain glucose tolerant.
Conclusions
Our findings demonstrate that disruption of Bscl2 specifically in developing adipocytes is sufficient to cause the early-onset generalised lipodystrophy observed in patients with mutations in BSCL2. However, this significant reduction in adipose mass does not cause the overt metabolic dysfunction seen in Bscl2 knockout mice, even following a high-fat diet challenge.
Original language | English |
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Pages (from-to) | 55-65 |
Number of pages | 11 |
Journal | Molecular Metabolism |
Volume | 10 |
Early online date | 31 Jan 2018 |
DOIs | |
Publication status | Published - 1 Apr 2018 |
Bibliographical note
Acknowledgements: The authors would like to thank Dr Cristian Olarte-Sanchez for his help with metabolic studies, James Redmore and James Thorburn for their contributions to data collection and analysis, Alison Richmond, Susan Clark and Ausra Lionikiene for technical support, and staff at the University of Aberdeen's Medical Research Facility and Microscopy & Histology Facility. We are very grateful for the gift of the Adiponectin-Cre mice from Dr. Evan Rosen (Beth Israel Deaconess Medical Centre and Harvard Medical School, Boston, USA). Work was supported by the Medical Research Council (GDM/JJR; MR/L002620/1, MC/PC/15077, KS/WPC; MR/M021394/1, AJR/CDB; MR/L022893/1), the Biotechnology and Biological Sciences Research Council (JJR; BB/K017772/1), the British Heart Foundation (MD; PG/14/43/30889, KS/WPC; BHF CoRE Bioinformatics Grant), NHS Grampian Endowments (AJR/CDB/JJR; Grant No. 16/11/032) and the NHS Grampian Rheumatology Department.Keywords
- BSCL2
- seipin
- CGL2
- lipodystrophy
- adipose tissue
- Browning
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Anke Roelofs
- School of Medicine, Medical Sciences & Nutrition, Medical Sciences - Senior Lecturer
- School of Medicine, Medical Sciences & Nutrition, MRC/Versus Arthritis Centre for Musculoskeletal Health and Work
- School of Medicine, Medical Sciences & Nutrition, Molecular and Cellular Function
- School of Medicine, Medical Sciences & Nutrition, Institute of Medical Sciences
- School of Medicine, Medical Sciences & Nutrition, Aberdeen Centre for Arthritis and Musculoskeletal Health (ACAMH)
Person: Academic