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Oláh T, Cucchiarini M, Madry H. Temporal progression of subchondral bone alterations in OA models involving induction of compromised meniscus integrity in mice and rats: A scoping review. Osteoarthritis Cartilage 2024; 32:1220-1234. [PMID: 38876436 DOI: 10.1016/j.joca.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 05/17/2024] [Accepted: 06/06/2024] [Indexed: 06/16/2024]
Abstract
OBJECTIVE To categorize the temporal progression of subchondral bone alterations induced by compromising meniscus integrity in mouse and rat models of knee osteoarthritis (OA). METHOD Scoping review of investigations reporting subchondral bone changes with appropriate negative controls in the different mouse and rat models of OA induced by compromising meniscus integrity. RESULTS The available literature provides appropriate temporal detail on subchondral changes in these models, covering the entire spectrum of OA with an emphasis on early and mid-term time points. Microstructural changes of the subarticular spongiosa are comprehensively described; those of the subchondral bone plate are not. In mouse models, global subchondral bone alterations are unidirectional, involving an advancing sclerosis of the trabecular structure over time. In rats, biphasic subchondral bone alterations begin with an osteopenic degeneration and loss of subchondral trabeculae, progressing to a late sclerosis of the entire subchondral bone. Rat models, independently from the applied technique, relatively faithfully mirror the early bone loss detected in larger animals, and the late subchondral bone sclerosis observed in human advanced OA. CONCLUSION Mice and rats allow us to study the microstructural consequences of compromising meniscus integrity at high temporal detail. Thickening of the subchondral bone plate, an early loss of thinner subarticular trabecular elements, followed by a subsequent sclerosis of the entire subchondral bone are all important and reliable hallmarks that occur in parallel with the advancing articular cartilage degeneration. Thoughtful decisions on the study design, laterality, selection of controls and volumes of interest are crucial to obtain meaningful data.
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Affiliation(s)
- Tamás Oláh
- Center of Experimental Orthopaedics, Saarland University, Homburg, Germany; Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
| | - Magali Cucchiarini
- Center of Experimental Orthopaedics, Saarland University, Homburg, Germany.
| | - Henning Madry
- Center of Experimental Orthopaedics, Saarland University, Homburg, Germany.
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2
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Zapata-Linares N, Loisay L, de Haro D, Berenbaum F, Hügle T, Geurts J, Houard X. Systemic and joint adipose tissue lipids and their role in osteoarthritis. Biochimie 2024:S0300-9084(24)00225-6. [PMID: 39343353 DOI: 10.1016/j.biochi.2024.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 08/09/2024] [Accepted: 09/26/2024] [Indexed: 10/01/2024]
Abstract
Osteoarthritis (OA) is a major disease whose prevalence increases with aging, sedentary lifestyles, and obesity. The association between obesity and OA has been well documented, but the precise mechanisms underlying this heightened risk remain unclear. While obesity imposes greater forces on joints, systemic fat-derived factors such as lipids or adipokine may potentially act on the pathophysiology of OA, but the exact role of these factors in weight-bearing and non-weight-bearing joints remains elusive. Intra-articular adipose tissues (IAAT) have gained significant attention for actively participating in OA pathogenesis by interacting with various joint tissues. Lipid content has been proposed as a diagnostic target for early OA detection and a potential source of biomarkers. Moreover, targeting a specific IAAT called infrapatellar fat pad (IFP) and its lipids hold promise for attenuating OA-associated inflammation. Conversely, bone marrow adipose tissue (BMAT), which was long thought to be an inert filling tissue, is now increasingly considered a dynamic tissue whose volume and lipid content regulate bone remodeling in pathological conditions. Given OA's ability to alter adipose tissues, particularly those within the joint (IFP and BMAT), and the influence of adipose tissues on OA pathogenesis, this review examines the lipids produced by OA-associated adipose tissues, shedding light on their potential role in OA pathophysiology and highlighting them as potential therapeutic targets.
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Affiliation(s)
- Natalia Zapata-Linares
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine (CRSA), F-75012, Paris, France
| | - Léa Loisay
- Service of Rheumatology, Department of Musculoskeletal Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Diego de Haro
- Service of Rheumatology, Department of Musculoskeletal Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Francis Berenbaum
- Rheumatology Department, AP-HP Saint-Antoine Hospital, 184, rue du Faubourg Saint-Antoine, F-75012, Paris, France
| | - Thomas Hügle
- Service of Rheumatology, Department of Musculoskeletal Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Jeroen Geurts
- Service of Rheumatology, Department of Musculoskeletal Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
| | - Xavier Houard
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine (CRSA), F-75012, Paris, France.
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Tencerova M, Duque G, Beekman KM, Corsi A, Geurts J, Bisschop PH, Paccou J. The Impact of Interventional Weight Loss on Bone Marrow Adipose Tissue in People Living with Obesity and Its Connection to Bone Metabolism. Nutrients 2023; 15:4601. [PMID: 37960254 PMCID: PMC10650495 DOI: 10.3390/nu15214601] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
This review focuses on providing physicians with insights into the complex relationship between bone marrow adipose tissue (BMAT) and bone health, in the context of weight loss through caloric restriction or metabolic and bariatric surgery (MBS), in people living with obesity (PwO). We summarize the complex relationship between BMAT and bone health, provide an overview of noninvasive imaging techniques to quantify human BMAT, and discuss clinical studies measuring BMAT in PwO before and after weight loss. The relationship between BMAT and bone is subject to variations based on factors such as age, sex, menopausal status, skeletal sites, nutritional status, and metabolic conditions. The Bone Marrow Adiposity Society (BMAS) recommends standardizing imaging protocols to increase comparability across studies and sites, they have identified both water-fat imaging (WFI) and spectroscopy (1H-MRS) as accepted standards for in vivo quantification of BMAT. Clinical studies measuring BMAT in PwO are limited and have shown contradictory results. However, BMAT tends to be higher in patients with the highest visceral adiposity, and inverse associations between BMAT and bone mineral density (BMD) have been consistently found in PwO. Furthermore, BMAT levels tend to decrease after caloric restriction-induced weight loss. Although weight loss was associated with overall fat loss, a reduction in BMAT did not always follow the changes in fat volume in other tissues. The effects of MBS on BMAT are not consistent among the studies, which is at least partly related to the differences in the study population, skeletal site, and duration of the follow-up. Overall, gastric bypass appears to decrease BMAT, particularly in patients with diabetes and postmenopausal women, whereas sleeve gastrectomy appears to increase BMAT. More research is necessary to evaluate changes in BMAT and its connection to bone metabolism, either in PwO or in cases of weight loss through caloric restriction or MBS, to better understand the role of BMAT in this context and determine the local or systemic factors involved.
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Affiliation(s)
- Michaela Tencerova
- Molecular Physiology of Bone, Institute of Physiology of the Czech Academy of Sciences, 14220 Prague, Czech Republic;
| | - Gustavo Duque
- Department of Medicine, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
| | - Kerensa M. Beekman
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands;
| | - Alessandro Corsi
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy;
| | - Jeroen Geurts
- Rheumatology, Department of Musculoskeletal Medicine, Lausanne University Hospital, 1011 Lausanne, Switzerland;
| | - Peter H. Bisschop
- Department of Endocrinology, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands;
| | - Julien Paccou
- Department of Rheumatology, MABLab ULR 4490, CHU Lille, University Lille, 59000 Lille, France
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4
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Bensreti H, Alhamad DW, Gonzalez AM, Pizarro-Mondesir M, Bollag WB, Isales CM, McGee-Lawrence ME. Update on the Role of Glucocorticoid Signaling in Osteoblasts and Bone Marrow Adipocytes During Aging. Curr Osteoporos Rep 2023; 21:32-44. [PMID: 36564571 PMCID: PMC9936962 DOI: 10.1007/s11914-022-00772-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/15/2022] [Indexed: 12/25/2022]
Abstract
PURPOSE OF REVIEW Bone marrow adipose tissue (BMAT) in the skeleton likely plays a variety of physiological and pathophysiological roles that are not yet fully understood. In elucidating the complex relationship between bone and BMAT, glucocorticoids (GCs) are positioned to play a key role, as they have been implicated in the differentiation of bone marrow mesenchymal stem cells (BMSCs) between osteogenic and adipogenic lineages. The purpose of this review is to illuminate aspects of both endogenous and exogenous GC signaling, including the influence of GC receptors, in mechanisms of bone aging including relationships to BMAT. RECENT FINDINGS Harmful effects of GCs on bone mass involve several cellular pathways and events that can include BMSC differentiation bias toward adipogenesis and the influence of mature BMAT on bone remodeling through crosstalk. Interestingly, BMAT involvement remains poorly explored in GC-induced osteoporosis and warrants further investigation. This review provides an update on the current understanding of the role of glucocorticoids in the biology of osteoblasts and bone marrow adipocytes (BMAds).
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Affiliation(s)
- Husam Bensreti
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Dima W Alhamad
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Alejandro Marrero Gonzalez
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Manuel Pizarro-Mondesir
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Wendy B Bollag
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Carlos M Isales
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Orthopaedic Surgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Meghan E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA.
- Department of Orthopaedic Surgery, Medical College of Georgia, Augusta University, Augusta, GA, USA.
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5
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Hariri H, Kose O, Bezdjian A, Daniel SJ, St-Arnaud R. USP53 Regulates Bone Homeostasis by Controlling Rankl Expression in Osteoblasts and Bone Marrow Adipocytes. J Bone Miner Res 2023; 38:578-596. [PMID: 36726200 DOI: 10.1002/jbmr.4778] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 01/12/2023] [Accepted: 01/19/2023] [Indexed: 02/03/2023]
Abstract
In the skeleton, osteoblasts and osteoclasts synchronize their activities to maintain bone homeostasis and integrity. Investigating the molecular mechanisms governing bone remodeling is critical and helps understand the underlying biology of bone disorders. Initially, we have identified the ubiquitin-specific peptidase gene (Usp53) as a target of the parathyroid hormone in osteoblasts and a regulator of mesenchymal stem cell differentiation. Mutations in USP53 have been linked to a constellation of developmental pathologies. However, the role of Usp53 in bone has never been visited. Here we show that Usp53 null mice have a low bone mass phenotype in vivo. Usp53 null mice exhibit a pronounced decrease in trabecular bone indices including trabecular bone volume (36%) and trabecular number (26%) along with an increase in trabecular separation (13%). Cortical bone parameters are also impacted, showing a reduction in cortical bone volume (12%) and cortical bone thickness (15%). As a result, the strength and mechanical bone properties of Usp53 null mice have been compromised. At the cellular level, the ablation of Usp53 perturbs bone remodeling, augments osteoblast-dependent osteoclastogenesis, and increases osteoclast numbers. Bone marrow adipose tissue volume increased significantly with age in Usp53-deficient mice. Usp53 null mice displayed increased serum receptor activator of NF-κB ligand (RANKL) levels, and Usp53-deficient osteoblasts and bone marrow adipocytes have increased expression of Rankl. Mechanistically, USP53 regulates Rankl expression by enhancing the interaction between VDR and SMAD3. This is the first report describing the function of Usp53 during skeletal development. Our results put Usp53 in display as a novel regulator of osteoblast-osteoclast coupling and open the door for investigating the involvement of USP53 in pathologies. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Hadla Hariri
- Research Centre, Shriners Hospital for Children-Canada, Montreal, Canada.,Department of Human Genetics, Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada
| | - Orhun Kose
- McGill Otolaryngology Sciences Laboratory, McGill University Health Centre-Research Institute, Montreal, Canada
| | - Aren Bezdjian
- McGill Otolaryngology Sciences Laboratory, McGill University Health Centre-Research Institute, Montreal, Canada
| | - Sam J Daniel
- McGill Otolaryngology Sciences Laboratory, McGill University Health Centre-Research Institute, Montreal, Canada.,Department of Otolaryngology-Head and Neck Surgery, McGill University, Montreal, Canada.,Department of Pediatric Surgery, McGill University, Montreal, Canada
| | - René St-Arnaud
- Research Centre, Shriners Hospital for Children-Canada, Montreal, Canada.,Department of Human Genetics, Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada.,Department of Surgery, Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada.,Department of Medicine, Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada
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Li Z, Bagchi DP, Zhu J, Bowers E, Yu H, Hardij J, Mori H, Granger K, Skjaerlund J, Mandair G, Abrishami S, Singer K, Hankenson KD, Rosen CJ, MacDougald OA. Constitutive bone marrow adipocytes suppress local bone formation. JCI Insight 2022; 7:160915. [PMID: 36048537 PMCID: PMC9675472 DOI: 10.1172/jci.insight.160915] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 08/31/2022] [Indexed: 12/15/2022] Open
Abstract
BM adipocytes (BMAd) are a unique cell population derived from BM mesenchymal progenitors and marrow adipogenic lineage precursors. Although they have long been considered to be a space filler within bone cavities, recent studies have revealed important physiological roles in hematopoiesis and bone metabolism. To date, the approaches used to study BMAd function have been confounded by contributions by nonmarrow adipocytes or by BM stromal cells. To address this gap in the field, we have developed a BMAd-specific Cre mouse model to deplete BMAds by expression of diphtheria toxin A (DTA) or by deletion of peroxisome proliferator-activated receptor gamma (Pparg). We found that DTA-induced loss of BMAds results in decreased hematopoietic stem and progenitor cell numbers and increased bone mass in BMAd-enriched locations, including the distal tibiae and caudal vertebrae. Elevated bone mass appears to be secondary to enhanced endosteal bone formation, suggesting a local effect caused by depletion of BMAd. Augmented bone formation with BMAd depletion protects mice from bone loss induced by caloric restriction or ovariectomy, and it facilitates the bone-healing process after fracture. Finally, ablation of Pparg also reduces BMAd numbers and largely recapitulates high-bone mass phenotypes observed with DTA-induced BMAd depletion.
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Affiliation(s)
- Ziru Li
- Department of Molecular & Integrative Physiology and
| | | | - Junxiong Zhu
- Department of Orthopedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Emily Bowers
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Hui Yu
- Department of Molecular & Integrative Physiology and
| | - Julie Hardij
- Department of Molecular & Integrative Physiology and
| | - Hiroyuki Mori
- Department of Molecular & Integrative Physiology and
| | | | - Jon Skjaerlund
- Department of Orthopedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Gurjit Mandair
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Simin Abrishami
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Kanakadurga Singer
- Department of Molecular & Integrative Physiology and
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Kurt D. Hankenson
- Department of Orthopedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Ormond A. MacDougald
- Department of Molecular & Integrative Physiology and
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Li Z, Bowers E, Zhu J, Yu H, Hardij J, Bagchi DP, Mori H, Lewis KT, Granger K, Schill RL, Romanelli SM, Abrishami S, Hankenson KD, Singer K, Rosen CJ, MacDougald OA. Lipolysis of bone marrow adipocytes is required to fuel bone and the marrow niche during energy deficits. eLife 2022; 11:e78496. [PMID: 35731039 PMCID: PMC9273217 DOI: 10.7554/elife.78496] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
To investigate roles for bone marrow adipocyte (BMAd) lipolysis in bone homeostasis, we created a BMAd-specific Cre mouse model in which we knocked out adipose triglyceride lipase (ATGL, Pnpla2 gene). BMAd-Pnpla2-/- mice have impaired BMAd lipolysis, and increased size and number of BMAds at baseline. Although energy from BMAd lipid stores is largely dispensable when mice are fed ad libitum, BMAd lipolysis is necessary to maintain myelopoiesis and bone mass under caloric restriction. BMAd-specific Pnpla2 deficiency compounds the effects of caloric restriction on loss of trabecular bone in male mice, likely due to impaired osteoblast expression of collagen genes and reduced osteoid synthesis. RNA sequencing analysis of bone marrow adipose tissue reveals that caloric restriction induces dramatic elevations in extracellular matrix organization and skeletal development genes, and energy from BMAd is required for these adaptations. BMAd-derived energy supply is also required for bone regeneration upon injury, and maintenance of bone mass with cold exposure.
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Affiliation(s)
- Ziru Li
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Emily Bowers
- University of Michigan Medical School, Department of PediatricsAnn ArborUnited States
| | - Junxiong Zhu
- Department of Orthopedic Surgery, University of Michigan Medical SchoolAnn ArborUnited States
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
| | - Hui Yu
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Julie Hardij
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Devika P Bagchi
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Hiroyuki Mori
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Kenneth T Lewis
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Katrina Granger
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Rebecca L Schill
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Steven M Romanelli
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Simin Abrishami
- University of Michigan Medical School, Department of PediatricsAnn ArborUnited States
| | - Kurt D Hankenson
- Department of Orthopedic Surgery, University of Michigan Medical SchoolAnn ArborUnited States
| | - Kanakadurga Singer
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
- University of Michigan Medical School, Department of PediatricsAnn ArborUnited States
| | | | - Ormond A MacDougald
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
- University of Michigan Medical School, Department of Internal MedicineAnn ArborUnited States
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8
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Romanelli SM, Lewis KT, Nishii A, Rupp AC, Li Z, Mori H, Schill RL, Learman BS, Rhodes CJ, MacDougald OA. BAd-CRISPR: Inducible gene knockout in interscapular brown adipose tissue of adult mice. J Biol Chem 2021; 297:101402. [PMID: 34774798 PMCID: PMC8661024 DOI: 10.1016/j.jbc.2021.101402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/26/2021] [Accepted: 11/09/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR/Cas9 has enabled inducible gene knockout in numerous tissues; however, its use has not been reported in brown adipose tissue (BAT). Here, we developed the brown adipocyte CRISPR (BAd-CRISPR) methodology to rapidly interrogate the function of one or multiple genes. With BAd-CRISPR, an adeno-associated virus (AAV8) expressing a single guide RNA (sgRNA) is administered directly to BAT of mice expressing Cas9 in brown adipocytes. We show that the local administration of AAV8-sgRNA to interscapular BAT of adult mice robustly transduced brown adipocytes and ablated expression of adiponectin, adipose triglyceride lipase, fatty acid synthase, perilipin 1, or stearoyl-CoA desaturase 1 by >90%. Administration of multiple AAV8 sgRNAs led to simultaneous knockout of up to three genes. BAd-CRISPR induced frameshift mutations and suppressed target gene mRNA expression but did not lead to substantial accumulation of off-target mutations in BAT. We used BAd-CRISPR to create an inducible uncoupling protein 1 (Ucp1) knockout mouse to assess the effects of UCP1 loss on adaptive thermogenesis in adult mice. Inducible Ucp1 knockout did not alter core body temperature; however, BAd-CRISPR Ucp1 mice had elevated circulating concentrations of fibroblast growth factor 21 and changes in BAT gene expression consistent with heat production through increased peroxisomal lipid oxidation. Other molecular adaptations predict additional cellular inefficiencies with an increase in both protein synthesis and turnover, and mitochondria with reduced reliance on mitochondrial-encoded gene expression and increased expression of nuclear-encoded mitochondrial genes. These data suggest that BAd-CRISPR is an efficient tool to speed discoveries in adipose tissue biology.
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Affiliation(s)
- Steven M Romanelli
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Kenneth T Lewis
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Akira Nishii
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Ziru Li
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Hiroyuki Mori
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Rebecca L Schill
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Brian S Learman
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Christopher J Rhodes
- Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, USA
| | - Ormond A MacDougald
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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