The central themes of our laboratory include the genetic regulation of insulin-like growth factor relative to skeletal metabolism, the relationship between marrow adipogenesis and osteoblastogenesis, and the interactions between whole body and skeletal metabolism. We use age, genetic, environmental, diet and pharmacologic manipulations in order to understand the complex regulation of bone remodeling. We use a variety of techniques to address our research questions, including microCT, DXA imaging, NMR, MRI, osmium tetroxide staining, immunohistochemistry, immunofluorescence, confocal microscopy, SeaHorse extracellular flux analysis, and metabolic cages.
Fig 1: Fluorescence microscopy of murine preosteoblasts.
One aspect of our research focuses on Insulin-like Growth Factor (IGF) signaling in bone and fat tissues. IGF is found circulating in the blood either in its free form or bound to IGF Binding Proteins (IGFBP). We are interested in understanding the in vivo roles of IGF binding proteins (IGFBP) namely IGFBP2 and IGFBP4. Our laboratory uses a global and conditional knockout murine model for these IGFBPs in order to understand their effects on the regulation of bone modeling and remodeling and fat acquisition.
Fig 2: Three-dimensional microCT of the distal femur trabecular bone.
Scientific Manager Victoria DeMambro, MS, has been critical for carrying out the IGFBP2 work. Previously, we reported sexually dimorphic bone mass and body composition phenotypes in Igfbp2–/- mice (-/-), where male mice exhibited decreased bone and increased fat mass, while female mice displayed increased bone but no changes in fat mass. To investigate the interaction between IGFBP-2 and estrogen, we use an ovariectomy model of post-menopausal bone loss. We have found that estrogen deficiency has a profound effect on body and bone composition in the absence of IGFBP-2 and may be related to changes in FGF-21. Ms. DeMambro is also Physiology Core manager and has been instrumental in developing technologies for our institute such as osmium tetroxide staining of marrow adipose tissue, metabolic cages, and Seahorse extracellular flux analysis. She is also leading projects related to how temperature homeostasis impacts bone metabolism.
Fig 3: MicroCT image of osmium-tetroxide stained marrow adipose tissue.
The lab also doing work in the area of IGFBP4. In our global knockout model for IGFBP4, we have observed intriguing gender-specific phenotypes both at the bone and fat levels. Indeed, while the IGFBP4 knockout female mice have decreased bone mineral density the males have more trabecular bone. In addition, only female IGFBP4 null mice were resistant to high fat diet-induced obesity whereas males gained weight. We combine our in vivo observations with in vitro cell culture models in order to understand the mechanisms through which those binding proteins act.
Fig 4: Oil Red O stained lipid droplets in adipocytes generated from ear mesenchymal stem cells.
Scientific Manager, Sheila Bornstein, MS, has been instrumental in studies related to the interplay of bone and fat under different conditions such as lactation, high fat diet, calorie restriction and cold exposure. Previously, we reported that metabolic changes during lactation of C57BL/6J mice were due in part to increased circulating FGF-21, which in turn could accentuate bone loss. Sheila Bornstein’s current work focuses on the interaction between high fat diet and skeletal metabolism in Adiponectin null mice and how marrow fat is regulated in response to calorie restriction. Sheila has also been instrumental in working with Dr. Rosen’s internal and external collaborators. A current collaboration is with Dr. Michaela Reagan of MMCRI, examining the effects of metformin on bone and marrow adiposity alone and in combination with high fat diet. This is incredibly important as approximately 20 million people in the U.S. have been diagnosed with type 2 diabetes and are treated with metformin, although the mechanism of action is not completely understood.
Visiting Scholar and Doctoral Candidate Adriana Lelis Carvalho, MS, came to us from the clinical research laboratory of Dr. Francisco Jose Albuquerque de Paula at the University of Sao Paolo in Ribeirao Preto, Brazil. She is interested in understanding how nutrition plays a role in the bone loss and bone marrow adipose tissue (BMAT) that is a well-described feature of T1DM. In our lab, Ms. Carvalho has used the streptozotocin-induced diabetic mouse model to study how diet composition modulates bone and marrow fat outcomes.
Fig 5: Immunohistochemistry staining showing insulin expression from pancreatic β-cells.
Staff Scientist Anyonya Guntur, PhD, is leading several projects related to bone development and its role in regulating whole body metabolism. Nocturnin (Noc) is a circadian regulated deadenylase, the loss of which is protective against bone loss during rosiglitazone therapy. This work could have major translational implications since the thiazolidinediones remain a widely used treatment for Type 2 diabetes mellitus. In course of our experiments with Nocturnin, we identified a potential mitochondrial target sequence in this protein and that Nocturnin modulates oxidative phosphorylation and glycolysis in preosteoblasts in vitro. Based on observations during the Nocturnin experiments, we started studying the role of mitochondrial respiration during osteoblast and adipocyte differentiation using the SeaHorse XF24 Analyzer (Link to physiology core).
We have also initiated a collaborative project with Dr. Martin Brand and Dr. Akos Gerencser at the Buck Institute of Aging and Dr. David Clemmons at the University of North Carolina to study how insulin Receptor substrate1 (IRS1) signaling (downstream of IGF1) regulates bone and fat. Victoria DeMambro in our lab identified IRS1 null spontaneous mouse model. Mice harboring this mutation are lean and have defects in adipose tissue along with reduced cortical bone and bone lengths. We have exploited this defect to study the role of IGF1 signaling in osteoblast and adipocytes respiration. In these collaborative studies we are also developing methods to investigate the role of PTH on osteoblast bioenergetics using ex vivo whole calvarial cultures to identify the contribution of glycolysis and oxidative phosphorylation to osteogenesis. (Manuscript in preparation with Victoria DeMambro, two-photon microscopy Dr.Akos Gerencser at Buck institute)
Fig 6: Two-photon microscopy image showing collagen in white (ex vivo calvariae) and alkaline phosphatase positive cells in green.
Staff Scientist Katherine Motyl, PhD, leads projects related to the role of temperature regulation and thermogenesis in regulating skeletal remodeling. Using Misty mice, a model with reduced innervation of brown adipose tissue and lower interscapular surface temperature, we demonstrated that sympathetic nervous system activation to compensate for these defects led to accelerated age-related bone loss. This study led to others examining how environmental manipulations like cold exposure modulated bone mass. We also utilize a variety of genetic models with disruptions in the temperature sensing and response pathways to understand the mechanisms of bone changes from cold. We have also developed a collaboration with Dr. Houseknecht at the University of New England to study how the atypical antipsychotic, risperidone, which has side effects ranging from cardiac arrest and hyperglycemia to altered temperature sensitivity, affects bone remodeling. Dr. Motyl has found that bone loss from risperidone is associated with activation of brown adipose tissue and increased energy expenditure. The beta-blocker propranolol prevented bone loss from risperidone, indicating that the sympathetic nervous system plays an important role in mediating at least the bone side effects of AA drugs.
Research Associate Phuong Le, MS, is continuing work examining the physiologic mechanisms by which DOCK7, the protein truncated in Misty mice, affects bone metabolism. She is currently aging Misty mice to 78 weeks in order to understand the interaction between brown adipose tissue and bone metabolism at advanced ages. Another focus of Phuong’s work on Misty is investigating changes in bone related to diet-induced thermogenesis by performing 13-week high fat diet feeding. Phuong Le is also instrumental in carrying out internal and external collaborative projects involving sophisticated primary culturing of osteoclasts, osteoblasts, and adipocytes.
Fig 7: Calcein stained calvarial organ culture.
Postdoctoral Research Fellow Kathleen Bishop, PhD, is collaborating with our Transgenic Core and utilizing CRISPR technology to ascertain the cell-specific consequences of DOCK7 deletion in mice. She is also involved in projects related to understanding how deletion of DOCK7 affects sympathetic nervous system output to bone.
Postdoctoral Research Fellow Elizabeth Rendina-Ruedy, PhD, and Graduate Student Carolina Figueroa are currently developing new projects within the framework of our general goals.
Fig 8: TRAP stained osteoclasts
Fig 9: H&E stain of femur marrow compartment with white adipocyte ghosts.
Rosen CJ, Ingelfinger JR. Unraveling the Function of FTO Variants. The New England journal of medicine. 2015; 373(10):964-5. PubMed [journal] PMID: 26287747
Fazeli PK, Faje AT, Cross EJ, Lee H, Rosen CJ, et al. Serum FGF-21 levels are associated with worsened radial trabecular bone microarchitecture and decreased radial bone strength in women with anorexia nervosa. Bone. 2015; 77:6-11. NIHMSID: NIHMS680372 PubMed [journal] PMID: 25868802, PMCID: PMC4447546
Sharma A, Flom PL, Rosen CJ, Schoenbaum EE. Racial differences in bone loss and relation to menopause among HIV-infected and uninfected women. Bone. 2015; 77:24-30. NIHMSID: NIHMS682538 PubMed [journal] PMID: 25896953, PMCID: PMC4418198
Lecka-Czernik B, Rosen CJ. Energy Excess, Glucose Utilization, and Skeletal Remodeling: New Insights. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 2015; 30(8):1356-61. PubMed [journal] PMID: 26094610
Lecka-Czernik B, Rosen CJ. Skeletal integration of energy homeostasis: Translational implications. Bone. 2015; PubMed [journal] PMID: 26211994
Motyl KJ, DeMambro VE, Barlow D, Olshan D, Nagano K, et al. Propranolol Attenuates Risperidone-Induced Trabecular Bone Loss in Female Mice. Endocrinology. 2015; 156(7):2374-83. PubMed [journal] PMID: 25853667, PMCID:
Taylor CL, Thomas PR, Aloia JF, Millard PS, Rosen CJ. Questions About Vitamin D
for Primary Care Practice: Input From an NIH Conference. The American journal of
medicine. 2015; PubMed [journal] PMID: 26071820
Reagan MR, Liaw L, Rosen CJ, Ghobrial IM. Dynamic interplay between bone and multiple myeloma: emerging roles of the osteoblast. Bone. 2015; 75:161-9. PubMed [journal] PMID: 25725265
Swanson CM, Shea SA, Stone KL, Cauley JA, Rosen CJ, et al. Obstructive sleep apnea and metabolic bone disease: insights into the relationship between bone and sleep. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 2015; 30(2):199-211. PubMed [journal] PMID: 25639209
Devlin MJ, Rosen CJ. The bone-fat interface: basic and clinical implications of marrow adiposity. The lancet. Diabetes & endocrinology. 2015; 3(2):141-7. NIHMSID: NIHMS603820 PubMed [journal] PMID: 24731667, PMCID: PMC4138282
- 1992-2002: Editorial Board, Journal of Bone and Mineral Research
- 1995-1999: Editorial Board, Journal of Clinical Endocrinology and Metabolism
- 1997-2002: Editor in Chief, Journal of Clinical Densitometry
- 2003-2007: Associate Editor, Journal Bone and Mineral Research
- 2003-2008:Editorial Board, Endocrinology
- 2006-Present: Editor in Chief, Primer on Metabolic Diseases, ASBMR
- 2009-2014: Associate Editor, Journal of Clinical Endocrinology and Metabolism
- 2010-2015: Associate Editor- Aging Cell
- 2013-Present: Senior Associate Editor- Journal of Bone and Mineral Research
- 2014- Present: Associate Editor- New England Journal of Medicine
- 2015- Present: Associate Editor- Endocrine Reviews
- 1988-Present: Member, The Endocrine Society, Bethesda, MD
- 1989-Present: Member, American Society of Bone and Mineral Research
- 1994-Present: Member, American Academy for the Advancement of Science
- 1995-Present: Member, New York Academy of Sciences
- 1996-2002: Member, Scientific Advisory Board, National Osteoporosis Foundation
- 1997-2001: Chair, NIH/NICHD Peer-Review Study Section “RFA: Peak Bone Mass”
- 1999-2002: Permanent Member, NIH Peer Review Group, OBM-2
- 2002-2003: President, American Society for Bone and Mineral Research
- 2002-2004: Chair, NIH Peer Review Group, OBM-2
- 2006-Present: Member, FDA Endocrinology and Metabolism Advisory Board
- 2007-2010: Member, NIH/NIAMS Advisory Council
- 2008-2011: Member, NIA Clinical Trials Advisory Board
- 2009-Present: Institute of Medicine Committee Member, Calcium and Vitamin D
- 2012-Present: Institute of Medicine Committee Member- Review of the NIH CTSA Program
- 2011-Present: American Board of Internal Medicine-Endocrinology and Metabolism Panel of Experts