28 results on '"Thomas H. Ambrosi"'
Search Results
2. Sexually dimorphic estrogen sensing in skeletal stem cells controls skeletal regeneration
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Tom W. Andrew, Lauren S. Koepke, Yuting Wang, Michael Lopez, Holly Steininger, Danielle Struck, Tatiana Boyko, Thomas H. Ambrosi, Xinming Tong, Yuxi Sun, Gunsagar S. Gulati, Matthew P. Murphy, Owen Marecic, Ruth Tevlin, Katharina Schallmoser, Dirk Strunk, Jun Seita, Stuart B. Goodman, Fan Yang, Michael T. Longaker, George P. Yang, and Charles K. F. Chan
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Science - Abstract
Abstract Sexually dimorphic tissues are formed by cells that are regulated by sex hormones. While a number of systemic hormones and transcription factors are known to regulate proliferation and differentiation of osteoblasts and osteoclasts, the mechanisms that determine sexually dimorphic differences in bone regeneration are unclear. To explore how sex hormones regulate bone regeneration, we compared bone fracture repair between adult male and female mice. We found that skeletal stem cell (SSC) mediated regeneration in female mice is dependent on estrogen signaling but SSCs from male mice do not exhibit similar estrogen responsiveness. Mechanistically, we found that estrogen acts directly on the SSC lineage in mice and humans by up-regulating multiple skeletogenic pathways and is necessary for the stem cell’s ability to self- renew and differentiate. Our results also suggest a clinically applicable strategy to accelerate bone healing using localized estrogen hormone therapy.
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- 2022
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3. Cross-species comparisons reveal resistance of human skeletal stem cells to inhibition by non-steroidal anti-inflammatory drugs
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L. Henry Goodnough, Thomas H. Ambrosi, Holly M. Steininger, M. Gohazrua K. Butler, Malachia Y. Hoover, HyeRan Choo, Noelle L. Van Rysselberghe, Michael J. Bellino, Julius A. Bishop, Michael J. Gardner, and Charles K. F. Chan
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skeletal stem cells (SSCs) ,non-steroid antiinflamatory drugs ,species specificity ,bone regeneration ,inflammation ,fracture healing ,Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
Fracture healing is highly dependent on an early inflammatory response in which prostaglandin production by cyclo-oxygenases (COX) plays a crucial role. Current patient analgesia regimens favor opioids over Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) since the latter have been implicated in delayed fracture healing. While animal studies broadly support a deleterious role of NSAID treatment to bone-regenerative processes, data for human fracture healing remains contradictory. In this study, we prospectively isolated mouse and human skeletal stem cells (SSCs) from fractures and compared the effect of various NSAIDs on their function. We found that osteochondrogenic differentiation of COX2-expressing mouse SSCs was impaired by NSAID treatment. In contrast, human SSCs (hSSC) downregulated COX2 expression during differentiation and showed impaired osteogenic capacity if COX2 was lentivirally overexpressed. Accordingly, short- and long-term treatment of hSSCs with non-selective and selective COX2 inhibitors did not affect colony forming ability, chondrogenic, and osteogenic differentiation potential in vitro. When hSSCs were transplanted ectopically into NSG mice treated with Indomethacin, graft mineralization was unaltered compared to vehicle injected mice. Thus, our results might contribute to understanding species-specific differences in NSAID sensitivity during fracture healing and support emerging clinical data which conflicts with other earlier observations that NSAID administration for post-operative analgesia for treatment of bone fractures are unsafe for patients.
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- 2022
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4. Optimizing Delivery of Therapeutic Growth Factors for Bone and Cartilage Regeneration
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Eri Takematsu, Matthew Murphy, Sophia Hou, Holly Steininger, Alina Alam, Thomas H. Ambrosi, and Charles K. F. Chan
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therapeutic growth factor delivery ,osteoarthritis ,osteoporosis ,controlled delivery ,osteoimmunology ,biomaterials ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
Bone- and cartilage-related diseases, such as osteoporosis and osteoarthritis, affect millions of people worldwide, impairing their quality of life and increasing mortality. Osteoporosis significantly increases the bone fracture risk of the spine, hip, and wrist. For successful fracture treatment and to facilitate proper healing in the most complicated cases, one of the most promising methods is to deliver a therapeutic protein to accelerate bone regeneration. Similarly, in the setting of osteoarthritis, where degraded cartilage does not regenerate, therapeutic proteins hold great promise to promote new cartilage formation. For both osteoporosis and osteoarthritis treatments, targeted delivery of therapeutic growth factors, with the aid of hydrogels, to bone and cartilage is a key to advance the field of regenerative medicine. In this review article, we propose five important aspects of therapeutic growth factor delivery for bone and cartilage regeneration: (1) protection of protein growth factors from physical and enzymatic degradation, (2) targeted growth factor delivery, (3) controlling GF release kinetics, (4) long-term stability of regenerated tissues, and (5) osteoimmunomodulatory effects of therapeutic growth factors and carriers/scaffolds.
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- 2023
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5. FGF21, not GCN2, influences bone morphology due to dietary protein restrictions
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Margaret A. McNulty, Brad A. Goupil, Diana C. Albarado, Teresa Castaño-Martinez, Thomas H. Ambrosi, Spela Puh, Tim J. Schulz, Annette Schürmann, Christopher D. Morrison, and Thomas Laeger
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Dietary restriction ,Protein restriction ,FGF21 ,GCN2 ,Microcomputed tomography ,Diseases of the musculoskeletal system ,RC925-935 - Abstract
Background: Dietary protein restriction is emerging as an alternative approach to treat obesity and glucose intolerance because it markedly increases plasma fibroblast growth factor 21 (FGF21) concentrations. Similarly, dietary restriction of methionine is known to mimic metabolic effects of energy and protein restriction with FGF21 as a required mechanism. However, dietary protein has been shown to be required for normal bone growth, though there is conflicting evidence as to the influence of dietary protein restriction on bone remodeling. The purpose of the current study was to evaluate the effect of dietary protein and methionine restriction on bone in lean and obese mice, and clarify whether FGF21 and general control nonderepressible 2 (GCN2) kinase, that are part of a novel endocrine pathway implicated in the detection of protein restriction, influence the effect of dietary protein restriction on bone. Methods: Adult wild-type (WT) or Fgf21 KO mice were fed a normal protein (18 kcal%; CON) or low protein (4 kcal%; LP) diet for 2 or 27 weeks. In addition, adult WT or Gcn2 KO mice were fed a CON or LP diet for 27 weeks. Young New Zealand obese (NZO) mice were placed on high-fat diets that provided protein at control (16 kcal%; CON), low levels (4 kcal%) in a high-carbohydrate (LP/HC) or high-fat (LP/HF) regimen, or on high-fat diets (protein, 16 kcal%) that provided methionine at control (0.86%; CON-MR) or low levels (0.17%; MR) for up to 9 weeks. Long bones from the hind limbs of these mice were collected and evaluated with micro-computed tomography (μCT) for changes in trabecular and cortical architecture and mass. Results: In WT mice the 27-week LP diet significantly reduced cortical bone, and this effect was enhanced by deletion of Fgf21 but not Gcn2. This decrease in bone did not appear after 2 weeks on the LP diet. In addition, Fgf21 KO mice had significantly less bone than their WT counterparts. In obese NZO mice dietary protein and methionine restriction altered bone architecture. The changes were mediated by FGF21 due to methionine restriction in the presence of cystine, which did not increase plasma FGF21 levels and did not affect bone architecture. Conclusions: This study provides direct evidence of a reduction in bone following long-term dietary protein restriction in a mouse model, effects that appear to be mediated by FGF21.
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- 2020
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6. A Revised Perspective of Skeletal Stem Cell Biology
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Thomas H. Ambrosi, Michael T. Longaker, and Charles K. F. Chan
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bone ,skeletal stem cell ,bone marrow/mesenchymal stromal/stem cell ,stem cell niche ,heterogeneity ,regeneration ,Biology (General) ,QH301-705.5 - Abstract
Bone-related maladies are a major health burden on modern society. Loss of skeletal integrity and regeneration capacity through aging, obesity, and disease follows from a detrimental shift in bone formation and resorption dynamics. Targeting tissue-resident adult stem cells offers a potentially innovative paradigm in the development of therapeutic strategies against organ dysfunction. While the essential role of skeletal stem cells (SSCs) for development, growth, and maintenance of the skeleton has been generally established, a common consensus on the exact identity and definition of a pure bona fide SSC population remains elusive. The controversies stem from conflicting results between different approaches and criteria for isolation, detection, and functional evaluation; along with the interchangeable usage of the terms SSC and “mesenchymal stromal/stem cell (MSC)”. A great number of prospective bone-forming stem cell populations have been reported with various characteristic markers, often describing overlapping cell populations with widely unexplored heterogeneity, species specificity, and distribution at distinct skeletal sites, bone regions, and microenvironments, thereby creating confusion that may complicate future advances in the field. In this review, we examine the state-of-the-art knowledge of SSC biology and try to establish a common ground for the definition and terminology of specific bone-resident stem cells. We also discuss recent advances in the identification of highly purified SSCs, which will allow detailed interrogation of SSC diversity and regulation at the single-cell level.
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- 2019
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7. A seed-and-soil theory for blood ageing
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Thomas H. Ambrosi and Charles K. F. Chan
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Cell Biology - Published
- 2023
8. Combination of Distinct Vascular Stem/Progenitor Cells for Neovascularization and Ischemic Rescue
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Liming Zhao, Andrew S. Lee, Koki Sasagawa, Jan Sokol, Yuting Wang, Ryan C. Ransom, Xin Zhao, Chao Ma, Holly M. Steininger, Lauren S. Koepke, Mimi R. Borrelli, Rachel E. Brewer, Lorene L.Y. Lee, Xianxi Huang, Thomas H. Ambrosi, Rahul Sinha, Malachia Y. Hoover, Jun Seita, Irving L. Weissman, Joseph C. Wu, Derrick C. Wan, Jun Xiao, Michael T. Longaker, Patricia K. Nguyen, and Charles K.F. Chan
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Cardiology and Cardiovascular Medicine - Abstract
BACKGROUND: Peripheral vascular disease remains a leading cause of vascular morbidity and mortality worldwide despite advances in medical and surgical therapy. Besides traditional approaches, which can only restore blood flow to native arteries, an alternative approach is to enhance the growth of new vessels, thereby facilitating the physiological response to ischemia. METHODS: The Actin CreER /R26 VT2/GK3 Rainbow reporter mouse was used for unbiased in vivo survey of injury-responsive vasculogenic clonal formation. Prospective isolation and transplantation were used to determine vessel-forming capacity of different populations. Single-cell RNA-sequencing was used to characterize distinct vessel-forming populations and their interactions. RESULTS: Two populations of distinct vascular stem/progenitor cells (VSPCs) were identified from adipose-derived mesenchymal stromal cells: VSPC1 is CD45-Ter119-Tie2+PDGFRa-CD31+CD105 high Sca1 low , which gives rise to stunted vessels (incomplete tubular structures) in a transplant setting, and VSPC2 which is CD45-Ter119-Tie2+PDGFRa+CD31-CD105 low Sca1 high and forms stunted vessels and fat. Interestingly, cotransplantation of VSPC1 and VSPC2 is required to form functional vessels that improve perfusion in the mouse hindlimb ischemia model. Similarly, VSPC1 and VSPC2 populations isolated from human adipose tissue could rescue the ischemic condition in mice. CONCLUSIONS: These findings suggest that autologous cotransplantation of synergistic VSPCs from nonessential adipose tissue can promote neovascularization and represents a promising treatment for ischemic disease.
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- 2023
9. Aged skeletal stem cells generate an inflammatory degenerative niche
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Xinming Tong, Matthew P. Murphy, Thomas H. Ambrosi, Norma Neff, Owen Marecic, Malachia Y. Hoover, Fan Yang, Maurizio Morri, Debashis Sahoo, Michael T. Longaker, Yuting Wang, Rachel E. Brewer, Holly Steininger, Lauren S. Koepke, Shamik Mascharak, Eun Young Seo, Irving L. Weissman, Charles Chan, Oyinkansola Ajanaku, Michael Lopez, Gunsagar S. Gulati, Adrian McArdle, Jan Sokol, Jun Seita, Rahul Sinha, Ruth Tevlin, Stephanie D. Conley, and Laura Lu
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Male ,Aging ,Bone Regeneration ,Stromal cell ,General Science & Technology ,1.1 Normal biological development and functioning ,Osteoclasts ,Bone Morphogenetic Protein 2 ,Biology ,Regenerative Medicine ,Article ,Bone and Bones ,Mice ,Stem Cell Research - Nonembryonic - Human ,Underpinning research ,medicine ,Animals ,Rejuvenation ,2.1 Biological and endogenous factors ,Myeloid Cells ,Cell Lineage ,Stem Cell Niche ,Aetiology ,Progenitor cell ,Bone regeneration ,Cellular Senescence ,Inflammation ,Fracture Healing ,Multidisciplinary ,Stem Cells ,Macrophage Colony-Stimulating Factor ,Inflammatory and immune system ,Mesenchymal stem cell ,Stem Cell Research ,Hematopoiesis ,Cell biology ,Haematopoiesis ,medicine.anatomical_structure ,Ageing ,Musculoskeletal ,Female ,Stem Cell Research - Nonembryonic - Non-Human ,Bone marrow ,Stem cell - Abstract
Loss of skeletal integrity during ageing and disease is associated with an imbalance in the opposing actions of osteoblasts and osteoclasts1. Here we show that intrinsic ageing of skeletal stem cells (SSCs)2 in mice alters signalling in the bone marrow niche and skews the differentiation of bone and blood lineages, leading to fragile bones that regenerate poorly. Functionally, aged SSCs have a decreased bone- and cartilage-forming potential but produce more stromal lineages that express high levels of pro-inflammatory and pro-resorptive cytokines. Single-cell RNA-sequencing studies link the functional loss to a diminished transcriptomic diversity of SSCs in aged mice, which thereby contributes to the transformation of the bone marrow niche. Exposure to a youthful circulation through heterochronic parabiosis or systemic reconstitution with young haematopoietic stem cells did not reverse the diminished osteochondrogenic activity of aged SSCs, or improve bone mass or skeletal healing parameters in aged mice. Conversely, the aged SSC lineage promoted osteoclastic activity and myeloid skewing by haematopoietic stem and progenitor cells, suggesting that the ageing of SSCs is a driver of haematopoietic ageing. Deficient bone regeneration in aged mice could only be returned to youthful levels by applying a combinatorial treatment of BMP2 and a CSF1 antagonist locally to fractures, which reactivated aged SSCs and simultaneously ablated the inflammatory, pro-osteoclastic milieu. Our findings provide mechanistic insights into the complex, multifactorial mechanisms that underlie skeletal ageing and offer prospects for rejuvenating the aged skeletal system. An analysis of skeletal stem cells in mice reveals that bone ageing occurs at the level of local niches affecting skeletal and haematopoietic lineage output, which may influence systemic aspects of multi-organ physiological ageing.
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- 2021
10. Articular cartilage regeneration by activated skeletal stem cells
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Thomas H. Ambrosi, Owen Marecic, Liming Zhao, Benjamin Levi, Marcin P. Walkiewicz, Michael T. Lopez, Yuting Wang, Charles Chan, Ryan C. Ransom, Xinming Tong, Matthew P. Murphy, Holly Steininger, Lauren S. Koepke, Stuart B. Goodman, Gunsagar S. Gulati, Michael T. Longaker, Derrick C. Wan, Malachia Y. Hoover, Natalina Quarto, Irving L. Weissman, and Fan Yang
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0301 basic medicine ,Pathology ,medicine.medical_specialty ,Cellular differentiation ,Population ,Osteoarthritis ,Bone morphogenetic protein 2 ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Degenerative disease ,0302 clinical medicine ,Medicine ,education ,education.field_of_study ,business.industry ,Regeneration (biology) ,Cartilage ,General Medicine ,Chondrogenesis ,medicine.disease ,030104 developmental biology ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Stem cell ,business ,Adult stem cell - Abstract
Osteoarthritis (OA) is a degenerative disease resulting in irreversible, progressive destruction of articular cartilage1. The etiology of OA is complex and involves a variety of factors, including genetic predisposition, acute injury and chronic inflammation2–4. Here we investigate the ability of resident skeletal stem-cell (SSC) populations to regenerate cartilage in relation to age, a possible contributor to the development of osteoarthritis5–7. We demonstrate that aging is associated with progressive loss of SSCs and diminished chondrogenesis in the joints of both mice and humans. However, a local expansion of SSCs could still be triggered in the chondral surface of adult limb joints in mice by stimulating a regenerative response using microfracture (MF) surgery. Although MF-activated SSCs tended to form fibrous tissues, localized co-delivery of BMP2 and soluble VEGFR1 (sVEGFR1), a VEGF receptor antagonist, in a hydrogel skewed differentiation of MF-activated SSCs toward articular cartilage. These data indicate that following MF, a resident stem-cell population can be induced to generate cartilage for treatment of localized chondral disease in OA. Endogenous skeletal stem cells are recruited to form cartilage in mice when stimulated by microfracture surgery together with localized delivery of growth factors, pointing to a new approach for treating cartilage defects.
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- 2020
11. Aging of Skeletal Stem Cells
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M Gohazrua K, Butler, Thomas H, Ambrosi, Matthew P, Murphy, and Charles K F, Chan
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General Medicine - Abstract
The skeletal system is generated and maintained by its progenitors, skeletal stem cells (SSCs), across the duration of life. Gradual changes associated with aging result in significant differences in functionality of SSCs. Declines in bone and cartilage production, increase of bone marrow adipose tissue, compositional changes of cellular microenvironments, and subsequent deterioration of external and internal structures culminate in the aged and weakened skeleton. The features and mechanisms of skeletal aging, and of its stem and progenitor cells in particular, are topics of recent investigation. The discovery of functionally homogeneous SSC populations with a defined cell surface phenotype has allowed for closer inspection of aging in terms of its effects on transcriptional regulation, cell function, and identity. Here, we review the aspects of SSC aging on both micro- and macroscopic levels. Up-to-date knowledge of SSC biology and aging is presented, and directions for future research and potential therapies are discussed. The realm of SSC-mediated bone aging remains an important component of global health and a necessary facet in our understanding of human aging.
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- 2022
12. Distinct skeletal stem cell types orchestrate long bone skeletogenesis
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Malachia Y. Hoover, Thomas H. Ambrosi, Norma Neff, Lauren S. Koepke, Holly Steininger, Maurizio Morri, Wan Jin Lu, Yuting Wang, Rahul Sinha, Michael T. Longaker, Matthew P. Murphy, Irving L. Weissman, and Charles Chan
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0301 basic medicine ,Male ,Mouse ,Long bone ,Inbred C57BL ,Regenerative medicine ,bone ,Mice ,0302 clinical medicine ,Bone Marrow ,Developmental ,Biology (General) ,Stem Cell Niche ,General Neuroscience ,Gene Expression Regulation, Developmental ,General Medicine ,Stem Cells and Regenerative Medicine ,Cell biology ,medicine.anatomical_structure ,Adipose Tissue ,Medicine ,Stem Cell Research - Nonembryonic - Non-Human ,Stem cell ,mesenchymal stromal cells ,Research Article ,Cell type ,QH301-705.5 ,Hematopoietic stem cell niche ,Science ,1.1 Normal biological development and functioning ,regenerative medicine ,Bone Marrow Cells ,Biology ,General Biochemistry, Genetics and Molecular Biology ,Bone and Bones ,diversity ,03 medical and health sciences ,stem cells ,Underpinning research ,medicine ,Animals ,Progenitor cell ,mouse ,Transplantation ,Bone Development ,General Immunology and Microbiology ,Mesenchymal stem cell ,Hematopoietic Stem Cells ,Stem Cell Research ,Mice, Inbred C57BL ,030104 developmental biology ,Gene Expression Regulation ,skeletal stem cells ,Musculoskeletal ,Bone marrow ,Biochemistry and Cell Biology ,Stromal Cells ,Pericytes ,Transcriptome ,030217 neurology & neurosurgery - Abstract
Skeletal stem and progenitor cell populations are crucial for bone physiology. Characterization of these cell types remains restricted to heterogenous bulk populations with limited information on whether they are unique or overlap with previously characterized cell types. Here we show, through comprehensive functional and single-cell transcriptomic analyses, that postnatal long bones of mice contain at least two types of bone progenitors with bona fide skeletal stem cell (SSC) characteristics. An early osteochondral SSC (ocSSC) facilitates long bone growth and repair, while a second type, a perivascular SSC (pvSSC), co-emerges with long bone marrow and contributes to shape the hematopoietic stem cell niche and regenerative demand. We establish that pvSSCs, but not ocSSCs, are the origin of bone marrow adipose tissue. Lastly, we also provide insight into residual SSC heterogeneity as well as potential crosstalk between the two spatially distinct cell populations. These findings comprehensively address previously unappreciated shortcomings of SSC research.
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- 2021
13. Author response: Distinct skeletal stem cell types orchestrate long bone skeletogenesis
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Thomas H Ambrosi, Rahul Sinha, Holly M Steininger, Malachia Y Hoover, Matthew P Murphy, Lauren S Koepke, Yuting Wang, Wan-Jin Lu, Maurizio Morri, Norma F Neff, Irving L Weissman, Michael T Longaker, and Charles KF Chan
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- 2021
14. Human skeletal stem cell aging
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Thomas H. Ambrosi, L. Henry Goodnough, and Charles Chan
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Sexual dimorphism ,Aging ,Regeneration (biology) ,Cell Biology ,Stem cell ,Biology ,Cell biology - Published
- 2020
15. Skeletal Stem Cells as the Developmental Origin of Cellular Niches for Hematopoietic Stem and Progenitor Cells
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Thomas H. Ambrosi and Charles Chan
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Cell type ,Regeneration (biology) ,Niche ,Mesenchymal stem cell ,Cell Differentiation ,Biology ,Hematopoietic Stem Cells ,Article ,Hematopoiesis ,Cell biology ,Haematopoiesis ,medicine.anatomical_structure ,Bone Marrow ,medicine ,Bone marrow ,Stem Cell Niche ,Progenitor cell ,Stem cell - Abstract
The skeletal system is a highly complex network of mesenchymal, hematopoietic, and vasculogenic stem cell lineages that coordinate the development and maintenance of defined microenvironments, so-called niches. Technological advancements in recent years have allowed for the dissection of crucial cell types as well as their autocrine and paracrine signals that regulate these niches during development, homeostasis, regeneration, and disease. Ingress of blood vessels and bone marrow hematopoiesis are initiated by skeletal stem cells (SSCs) and their more committed downstream lineage cell types that direct shape and form of skeletal elements. In this chapter, we focus on the role of SSCs as the developmental origin of niches for hematopoietic stem and progenitor cells. We discuss latest updates in the definition of SSCs, cellular processes establishing and maintaining niches, as well as alterations of stem cell microenvironments promoting malignancies. We conclude with an outlook on future studies that could take advantage of SSC-niche engineering as a basis for the development of new therapeutic tools to not only treat bone-related diseases but also maladies stemming from derailed niche dynamics altering hematopoietic output.
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- 2021
16. Delayed Union of a Diaphyseal Forearm Fracture Associated With Impaired Osteogenic Differentiation of Prospectively Isolated Human Skeletal Stem Cells
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Malcolm R. DeBaun, Charles Chan, L. Henry Goodnough, Geoffrey D. Abrams, Michael J. Gardner, Julius A. Bishop, Holly Steininger, Thomas H. Ambrosi, and Timothy R. McAdams
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BONE CELLS ,medicine.medical_specialty ,INJURY/FRACTURE HEALING ,Physical Injury - Accidents and Adverse Effects ,Endocrinology, Diabetes and Metabolism ,Nonunion ,STROMAL ,Case Report ,Bone healing ,Case Reports ,Diseases of the musculoskeletal system ,ORTHOPEDICS ,Regenerative Medicine ,FRACTURE HEALING ,Bone cell ,medicine ,INJURY ,Orthopedics and Sports Medicine ,Orthopedic surgery ,business.industry ,medicine.disease ,Stem Cell Research ,Surgery ,RC925-935 ,Musculoskeletal ,Delayed union ,Etiology ,Stem cell ,Forearm fracture ,business ,RD701-811 ,STROMAL/STEM CELLS ,STEM CELLS - Abstract
Delayed union or nonunion are relatively rare complications after fracture surgery, but when they do occur, they can result in substantial morbidity for the patient. In many cases, the etiology of impaired fracture healing is uncertain and attempts to determine the molecular basis for delayed union and nonunion formation have been limited. Prospectively isolating skeletal stem cells (SSCs) from fracture tissue samples at the time of surgical intervention represent a feasible methodology to determine a patient's biologic risk for compromised fracture healing. This report details a case in which functional in vitro readouts of SSCs derived from human fracture tissue at time of injury predicted a poor fracture healing outcome. This case suggests that it may be feasible to stratify a patient's fracture healing capacity and predict compromised fracture healing by prospectively isolating and analyzing SSCs during the index fracture surgery. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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- 2020
17. Author response for 'Delayed Union of a Diaphyseal Forearm Fracture Associated with Impaired Osteogenic Differentiation of Prospectively Isolated Human Skeletal Stem Cells'
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Thomas H. Ambrosi, Holly Steininger, Malcolm R. DeBaun, Timothy R. McAdams, Michael J. Gardner, Geoffrey D. Abrams, Charles Chan, Julius A. Bishop, and L. Henry Goodnough
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Pathology ,medicine.medical_specialty ,business.industry ,Delayed union ,Medicine ,Stem cell ,Forearm fracture ,business - Published
- 2020
18. Geriatric fragility fractures are associated with a human skeletal stem cell defect
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Malachia Y. Hoover, Jun Seita, L. Henry Goodnough, Julius A. Bishop, Liming Zhao, Charles Chan, Thomas H. Ambrosi, Emiley Kim, Owen Marecic, Holly Steininger, Michael J. Gardner, and Lauren S. Koepke
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0301 basic medicine ,Male ,Aging ,Regenerative Medicine ,Medical and Health Sciences ,Transcriptome ,Fractures, Bone ,0302 clinical medicine ,Stem Cell Research - Nonembryonic - Human ,80 and over ,Aged, 80 and over ,medicine.diagnostic_test ,Wnt signaling pathway ,Cell Differentiation ,Skeletal ,Biological Sciences ,Middle Aged ,Adult Stem Cells ,Muscle ,Stem Cell Research - Nonembryonic - Non-Human ,Original Article ,Female ,Stem cell ,bone healing ,Adult ,Adolescent ,Bone healing ,Biology ,Flow cytometry ,03 medical and health sciences ,Young Adult ,Downregulation and upregulation ,medicine ,Humans ,Progenitor cell ,Bone ,Muscle, Skeletal ,Aged ,aging ,Cell Biology ,Stem Cell Research ,In vitro ,030104 developmental biology ,Geriatrics ,Musculoskeletal ,sexual dimorphism ,human skeletal stem cell ,Cancer research ,geriatric fractures ,Fractures ,030217 neurology & neurosurgery ,Developmental Biology - Abstract
Fragility fractures have a limited capacity to regenerate, and impaired fracture healing is a leading cause of morbidity in the elderly. The recent identification of a highly purified bona fide human skeletal stem cell (hSSC) and its committed downstream progenitor cell populations provides an opportunity for understanding the mechanism of age‐related compromised fracture healing from the stem cell perspective. In this study, we tested whether hSSCs isolated from geriatric fractures demonstrate intrinsic functional defects that drive impaired healing. Using flow cytometry, we analyzed and isolated hSSCs from callus tissue of five different skeletal sites (n = 61) of patients ranging from 13 to 94 years of age for functional and molecular studies. We observed that fracture‐activated amplification of hSSC populations was comparable at all ages. However, functional analysis of isolated stem cells revealed that advanced age significantly correlated with reduced osteochondrogenic potential but was not associated with decreased in vitro clonogenicity. hSSCs derived from women displayed an exacerbated functional decline with age relative to those of aged men. Transcriptomic comparisons revealed downregulation of skeletogenic pathways such as WNT and upregulation of senescence‐related pathways in young versus older hSSCs. Strikingly, loss of Sirtuin1 expression played a major role in hSSC dysfunction but re‐activation by trans‐resveratrol or a small molecule compound restored in vitro differentiation potential. These are the first findings that characterize age‐related defects in purified hSSCs from geriatric fractures. Our results provide a foundation for future investigations into the mechanism and reversibility of skeletal stem cell aging in humans., Human skeletal stem cells (hSSCs) are present and accumulate at fracture sites independent of age. Impaired healing in the elderly might underlie functional defects in hSSCs which are exacerbated in women. Re‐activation of Sirt1 rejuvenates geriatric hSSCs independent of sex.
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- 2020
19. The emerging role of bone marrow adipose tissue in bone health and dysfunction
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Tim J. Schulz and Thomas H. Ambrosi
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0301 basic medicine ,Adipose tissue ,Endocrine System ,Biology ,Bioinformatics ,Models, Biological ,Bone and Bones ,Bone remodeling ,03 medical and health sciences ,Paracrine signalling ,Bone Marrow ,Paracrine Communication ,Drug Discovery ,medicine ,Animals ,Humans ,Genetics (clinical) ,Regeneration (biology) ,Mesenchymal stem cell ,Haematopoiesis ,030104 developmental biology ,medicine.anatomical_structure ,Adipose Tissue ,Adipogenesis ,Molecular Medicine ,Bone marrow - Abstract
Replacement of red hematopoietic bone marrow with yellow adipocyte-rich marrow is a conserved physiological process among mammals. The extent of this conversion is influenced by a wide array of pathological and non-pathological conditions. Of particular interest is the observation that some marrow adipocyte-inducing factors seem to oppose each other, for instance obesity and caloric restriction. Intriguingly, several important molecular characteristics of bone marrow adipose tissue (BMAT) are distinct from the classical depots of white and brown fat tissue. This depot of fat has recently emerged as an active part of the bone marrow niche that exerts paracrine and endocrine functions thereby controlling osteogenesis and hematopoiesis. While some functions of BMAT may be beneficial for metabolic adaptation and bone homeostasis, respectively, most findings assign bone fat a detrimental role during regenerative processes, such as hematopoiesis and osteogenesis. Thus, an improved understanding of the biological mechanisms leading to formation of BMAT, its molecular characteristics, and its physiological role in the bone marrow niche is warranted. Here we review the current understanding of BMAT biology and its potential implications for health and the development of pathological conditions.
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- 2017
20. FGF21, not GCN2, influences bone morphology due to dietary protein restrictions
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Thomas Laeger, Tim J. Schulz, Diana C. Albarado, Brad A. Goupil, Thomas H. Ambrosi, Annette Schürmann, Spela Puh, Teresa Castaño-Martinez, Margaret A. McNulty, and Christopher D. Morrison
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0301 basic medicine ,medicine.medical_specialty ,lcsh:Diseases of the musculoskeletal system ,FGF21 ,Low protein ,Endocrinology, Diabetes and Metabolism ,Dietary restriction ,Cystine ,030209 endocrinology & metabolism ,Biology ,Article ,Bone remodeling ,Microcomputed tomography ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Internal medicine ,medicine ,Endocrine system ,Orthopedics and Sports Medicine ,Obesity ,Metabolic and endocrine ,Protein restriction ,GCN2 ,Nutrition ,2. Zero hunger ,Methionine ,Kinase ,medicine.anatomical_structure ,Endocrinology ,chemistry ,Cortical bone ,030101 anatomy & morphology ,lcsh:RC925-935 - Abstract
BackgroundDietary protein restriction is emerging as an alternative approach to treat obesity and glucose intolerance because it markedly increases plasma fibroblast growth factor 21 (FGF21) concentrations. Similarly, dietary restriction of methionine is known to mimic metabolic effects of energy and protein restriction with FGF21 as a required mechanism. However, dietary protein has been shown to be required for normal bone growth, though there is conflicting evidence as to the influence of dietary protein restriction on bone remodeling. The purpose of the current study was to evaluate the effect of dietary protein and methionine restriction on bone in lean and obese mice, and clarify whether FGF21 and general control nonderepressible 2 (GCN2) kinase, that are part of a novel endocrine pathway implicated in the detection of protein restriction, influence the effect of dietary protein restriction on bone.MethodsAdult wild-type (WT) or Fgf21 KO mice were fed a normal protein (18kcal%; CON) or low protein (4kcal%; LP) diet for 2 or 27weeks. In addition, adult WT or Gcn2 KO mice were fed a CON or LP diet for 27weeks. Young New Zealand obese (NZO) mice were placed on high-fat diets that provided protein at control (16kcal%; CON), low levels (4kcal%) in a high-carbohydrate (LP/HC) or high-fat (LP/HF) regimen, or on high-fat diets (protein, 16kcal%) that provided methionine at control (0.86%; CON-MR) or low levels (0.17%; MR) for up to 9weeks. Long bones from the hind limbs of these mice were collected and evaluated with micro-computed tomography (μCT) for changes in trabecular and cortical architecture and mass.ResultsIn WT mice the 27-week LP diet significantly reduced cortical bone, and this effect was enhanced by deletion of Fgf21 but not Gcn2. This decrease in bone did not appear after 2weeks on the LP diet. In addition, Fgf21 KO mice had significantly less bone than their WT counterparts. In obese NZO mice dietary protein and methionine restriction altered bone architecture. The changes were mediated by FGF21 due to methionine restriction in the presence of cystine, which did not increase plasma FGF21 levels and did not affect bone architecture.ConclusionsThis study provides direct evidence of a reduction in bone following long-term dietary protein restriction in a mouse model, effects that appear to be mediated by FGF21.
- Published
- 2019
21. A Focused Low-Intensity Pulsed Ultrasound (FLIPUS) System for Cell Stimulation: Physical and Biological Proof of Principle
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Karen Ruschke, Thomas H. Ambrosi, Anke Kadow-Romacker, Kay Raum, Petra Knaus, Klaus-Vitold Jenderka, and Regina Puts
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0301 basic medicine ,Bone Regeneration ,Materials science ,Acoustics and Ultrasonics ,Cell Survival ,Apoptosis ,Low-intensity pulsed ultrasound ,Bone tissue ,Rats, Sprague-Dawley ,03 medical and health sciences ,medicine ,Animals ,Computer Simulation ,Cell stimulation ,Electrical and Electronic Engineering ,Bone regeneration ,Instrumentation ,Cells, Cultured ,business.industry ,Ultrasound ,Mesenchymal Stem Cells ,Rats ,030104 developmental biology ,medicine.anatomical_structure ,Transducer ,Ultrasonic Waves ,Duty cycle ,Rabbits ,business ,Biomarkers ,Intensity (heat transfer) ,Biomedical engineering - Abstract
Quantitative ultrasound (QUS) is a promising technique for bone tissue evaluation. Highly focused transducers used for QUS also have the capability to be applied for tissue-regenerative purposes and can provide spatially limited deposition of acoustic energy. We describe a focused low-intensity pulsed ultrasound (FLIPUS) system, which has been developed for the stimulation of cell monolayers in the defocused far field of the transducer through the bottom of the well plate. Tissue culture well plates, carrying the cells, were incubated in a special chamber, immersed in a temperature-controlled water tank. A stimulation frequency of 3.6 MHz provided an optimal sound transmission through the polystyrene well plate. The ultrasound was pulsed for 20 min daily at 100-Hz repetition frequency with 27.8% duty cycle. The calibrated output intensity corresponded to ${{{I}}_{{\text{SATA}}}} = 44.5 \pm 7.1\;{\text{mW}}/\text{cm}^{2}$ , which is comparable to the most frequently reported nominal output levels in LIPUS studies. No temperature change by the ultrasound exposure was observed in the well plate. The system was used to stimulate rat mesenchymal stem cells (rMSCs). The applied intensity had no apoptotic effect and enhanced the expression of osteogenic markers, i.e., osteopontin (OPN), collagen 1 (Col-1), the osteoblast-specific transcription factor—Runx-2 and E11 protein, an early osteocyte marker, in stimulated cells on day 5. The proposed FLIPUS setup opens new perspectives for the evaluation of the mechanistic effects of LIPUS.
- Published
- 2016
22. Loss of the Hematopoietic Stem Cell Factor GATA2 in the Osteogenic Lineage Impairs Trabecularization and Mechanical Strength of Bone
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Susanne Mathia, Sebastiaan H. Meijsing, Michael Schupp, Sascha Sauer, Thomas H. Ambrosi, Mario Thiele, Georg Seifert, Alexander Tolkachov, Matthias Muenzner, Melissa Bothe, Georg N. Duda, Marjo Salminen, Cornelius Fischer, Chung-Ting Han, Tim J. Schulz, Doctoral Programme in Clinical Veterinary Medicine, Marjo Salminen / Principal Investigator, Veterinary Biochemistry and Cell Biology, and Veterinary Biosciences
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0301 basic medicine ,Male ,ACTIVATED RECEPTOR-GAMMA ,GATA2 Deficiency ,Cellular differentiation ,Inbred C57BL ,Regenerative Medicine ,Medical and Health Sciences ,bone ,DEFICIENT MICE ,Bone remodeling ,Fractures, Bone ,Mice ,Stem Cell Research - Nonembryonic - Human ,Osteogenesis ,2.1 Biological and endogenous factors ,Developmental ,Aetiology ,mesenchymal stem cell ,Mice, Inbred C3H ,ADIPOCYTE DIFFERENTIATION ,GATA2 ,Hematopoietic stem cell ,Gene Expression Regulation, Developmental ,Nuclear Proteins ,Osteoblast ,Cell Differentiation ,3T3 Cells ,Biological Sciences ,Inbred C3H ,Cell biology ,CRE RECOMBINASE ,GATA2 Transcription Factor ,Haematopoiesis ,Blood ,medicine.anatomical_structure ,Cellular Microenvironment ,osteoblast ,Stem Cell Research - Nonembryonic - Non-Human ,Stem cell ,trabecularization ,OSTEOCLAST DEVELOPMENT ,CONTROL ADIPOGENESIS ,REGULATES DIFFERENTIATION ,Research Article ,Smad5 Protein ,LARGE GENE LISTS ,1.1 Normal biological development and functioning ,Bone Marrow Cells ,Biology ,Bone and Bones ,Cell Line ,Smad1 Protein ,03 medical and health sciences ,Underpinning research ,Osteoclast ,medicine ,Animals ,Molecular Biology ,Transplantation ,Binding Sites ,Mesenchymal Stem Cells ,Cell Biology ,Stem Cell Research ,Hematopoietic Stem Cells ,Mice, Inbred C57BL ,030104 developmental biology ,Gene Expression Regulation ,Musculoskeletal ,Smad8 Protein ,BROWN ADIPOCYTES ,Osteoporosis ,1182 Biochemistry, cell and molecular biology ,TRANSCRIPTION FACTOR GATA-2 ,Fractures ,Developmental Biology ,Transcription Factors - Abstract
The transcription factor GATA2 is required for expansion and differentiation of hematopoietic stem cells (HSCs). In mesenchymal stem cells (MSCs), GATA2 blocks adipogenesis, but its biological relevance and underlying genomic events are unknown. We report a dual function of GATA2 in bone homeostasis. GATA2 in MSCs binds near genes involved in skeletal system development and colocalizes with motifs for FOX and HOX transcription factors, known regulators of skeletal development. Ectopic GATA2 blocks osteoblastogenesis by interfering with SMAD1/5/8 activation. MSC-specific deletion of GATA2 in mice increases the numbers and differentiation capacity of bone-derived precursors, resulting in elevated bone formation. Surprisingly, MSC-specific GATA2 deficiency impairs the trabecularization and mechanical strength of bone, involving reduced MSC expression of the osteoclast inhibitor osteoprotegerin and increased osteoclast numbers. Thus, GATA2 affects bone turnover via MSC-autonomous and indirect effects. By regulating bone trabecularization, GATA2 expression in the osteogenic lineage may contribute to the anatomical and cellular microenvironment of the HSC niche required for hematopoiesis.
- Published
- 2018
23. Loss of periostin occurs in aging adipose tissue of mice and its genetic ablation impairs adipose tissue lipid metabolism
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Matthias Kern, Sabrina Gohlke, Annette Schürmann, Antonia Graja, Matthias Blüher, Thomas H. Ambrosi, Anne-Marie Jank, Tim J. Schulz, Krasimira Aleksandrova, Francisco Garcia-Carrizo, Siegfried Ussar, and Wenke Jonas
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0301 basic medicine ,Male ,Aging ,Messenger ,Adipose tissue ,White adipose tissue ,Inbred C57BL ,Regenerative Medicine ,Medical and Health Sciences ,Oral and gastrointestinal ,chemistry.chemical_compound ,Mice ,Adipocyte ,80 and over ,2.1 Biological and endogenous factors ,Body Size ,Aetiology ,Aged, 80 and over ,Mice, Knockout ,periostin ,Matricellular protein ,Thermogenesis ,Organ Size ,Biological Sciences ,Middle Aged ,adipose tissue ,Cold Temperature ,fatty acid metabolism ,Adipogenesis ,adipogenic progenitor cells ,Stem Cell Research - Nonembryonic - Non-Human ,Female ,Original Article ,Adipogenic Progenitor Cells ,Adipose Tissue ,Extracellular Matrix ,Fatty Acid Metabolism ,Periostin ,Adult ,medicine.medical_specialty ,Knockout ,1.1 Normal biological development and functioning ,extracellular matrix ,Biology ,Diet, High-Fat ,03 medical and health sciences ,Young Adult ,Adrenergic Agents ,Underpinning research ,Internal medicine ,medicine ,Department Sport- und Gesundheitswissenschaften ,Animals ,Humans ,ddc:610 ,Obesity ,RNA, Messenger ,Metabolic and endocrine ,Nutrition ,Aged ,Lipid metabolism ,Cell Biology ,Feeding Behavior ,Sterol Esterase ,Stem Cell Research ,Lipid Metabolism ,Diet ,Enzyme Activation ,Mice, Inbred C57BL ,High-Fat ,030104 developmental biology ,Endocrinology ,chemistry ,RNA ,Liver function ,Digestive Diseases ,Cell Adhesion Molecules ,Gene Deletion ,Developmental Biology - Abstract
Remodeling of the extracellular matrix is a key component of the metabolic adaptations of adipose tissue in response to dietary and physiological challenges. Disruption of its integrity is a well‐known aspect of adipose tissue dysfunction, for instance, during aging and obesity. Adipocyte regeneration from a tissue‐resident pool of mesenchymal stem cells is part of normal tissue homeostasis. Among the pathophysiological consequences of adipogenic stem cell aging, characteristic changes in the secretory phenotype, which includes matrix‐modifying proteins, have been described. Here, we show that the expression of the matricellular protein periostin, a component of the extracellular matrix produced and secreted by adipose tissue‐resident interstitial cells, is markedly decreased in aged brown and white adipose tissue depots. Using a mouse model, we demonstrate that the adaptation of adipose tissue to adrenergic stimulation and high‐fat diet feeding is impaired in animals with systemic ablation of the gene encoding for periostin. Our data suggest that loss of periostin attenuates lipid metabolism in adipose tissue, thus recapitulating one aspect of age‐related metabolic dysfunction. In human white adipose tissue, periostin expression showed an unexpected positive correlation with age of study participants. This correlation, however, was no longer evident after adjusting for BMI or plasma lipid and liver function biomarkers. These findings taken together suggest that age‐related alterations of the adipose tissue extracellular matrix may contribute to the development of metabolic disease by negatively affecting nutrient homeostasis.
- Published
- 2017
24. Adipocyte Accumulation in the Bone Marrow during Obesity and Aging Impairs Stem Cell-Based Hematopoietic and Bone Regeneration
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Tim J. Schulz, Anne Marie Jank, Lena Woelk, Darren W. Logan, Hua Fan, Luis R. Saraiva, Carla Bocian, Antonio Scialdone, Thomas H. Ambrosi, Annette Schürmann, Sabrina Gohlke, and Antonia Graja
- Subjects
0301 basic medicine ,Aging ,Bone Regeneration ,Dipeptidyl Peptidase 4 ,Mice, Transgenic ,Bone healing ,DPP4 ,Biology ,Article ,adipogenesis ,03 medical and health sciences ,Mice ,adipogenic progenitors ,0302 clinical medicine ,Bone Marrow ,Genetics ,medicine ,Adipocytes ,Humans ,Animals ,Obesity ,Bone regeneration ,mesenchymal stem cells ,Regeneration (biology) ,Mesenchymal stem cell ,Adipocyte Accumulation ,Hematopoietic Stem Cell Transplantation ,Cell Biology ,Cell biology ,Hematopoiesis ,Haematopoiesis ,030104 developmental biology ,medicine.anatomical_structure ,bone marrow adipose tissue ,Adipose Tissue ,regeneration ,030220 oncology & carcinogenesis ,Immunology ,Molecular Medicine ,Bone marrow ,bone healing ,Stem cell - Abstract
Summary Aging and obesity induce ectopic adipocyte accumulation in bone marrow cavities. This process is thought to impair osteogenic and hematopoietic regeneration. Here we specify the cellular identities of the adipogenic and osteogenic lineages of the bone. While aging impairs the osteogenic lineage, high-fat diet feeding activates expansion of the adipogenic lineage, an effect that is significantly enhanced in aged animals. We further describe a mesenchymal sub-population with stem cell-like characteristics that gives rise to both lineages and, at the same time, acts as a principal component of the hematopoietic niche by promoting competitive repopulation following lethal irradiation. Conversely, bone-resident cells committed to the adipocytic lineage inhibit hematopoiesis and bone healing, potentially by producing excessive amounts of Dipeptidyl peptidase-4, a protease that is a target of diabetes therapies. These studies delineate the molecular identity of the bone-resident adipocytic lineage, and they establish its involvement in age-dependent dysfunction of bone and hematopoietic regeneration., Graphical Abstract, Highlights • A stem cell-like population produces adipogenic and osteogenic lineages in bone • Aging and high-fat diet specifically promote expansion of the adipogenic lineage • Multipotent cells promote and adipogenic cells reduce hematopoietic reconstitution • Adipogenic cells inhibit fracture repair, which is restored by DPP4 inactivation, Ambrosi, Schulz, and colleagues define a stem cell-like population that gives rise to osteogenic progeny and promotes hematopoietic reconstitution. Aging and high-fat diet reprogram the mesenchymal lineage to preferentially give rise to adipogenic cells that impair reconstitution and bone fracture healing. Bone tissue repair is fully restored by DPP4 inhibition.
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- 2016
25. Identification of the Human Skeletal Stem Cell
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Matthew P. Murphy, Jun Seita, Michael T. Longaker, Gunsagar S. Gulati, Anoop Manjunath, Thomas H. Ambrosi, Rahul Sinha, Owen Marecic, Katharina Schallmoser, Michael Lopez, Wan Jin Lu, Irving L. Weissman, Taylor Wearda, Stuart B. Goodman, Eun Young Seo, Julius A. Bishop, Michael J. Gardner, Tripp Leavitt, Andreas Reinisch, Taylor Siebel, Debashis Sahoo, Rachel E. Brewer, Allison Nguyen, Derrick C. Wan, Howard Y. Chang, Lauren S. Koepke, Justin Vincent Tompkins, Ankit Salhotra, Henry Goodnough, Ravindra Majeti, Mimi R. Borrelli, Ava C. Carter, Charles Chan, Karen Chan, Ryan C. Ransom, and Stephanie D. Conley
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0301 basic medicine ,Adipose tissue ,HSC ,Inbred C57BL ,Regenerative Medicine ,bone ,Medical and Health Sciences ,Mice ,Stem Cell Research - Nonembryonic - Human ,2.1 Biological and endogenous factors ,ATAC-sequencing ,Aetiology ,cartilage ,Induced pluripotent stem cell ,Stem Cell Research - Induced Pluripotent Stem Cell - Human ,Stem Cells ,Cell Differentiation ,Biological Sciences ,single cell RNA-sequencing ,Cell biology ,Haematopoiesis ,medicine.anatomical_structure ,Stem Cell Research - Nonembryonic - Non-Human ,Single-Cell Analysis ,Stem cell ,Signal Transduction ,and stromal progenitor ,bone fracture repair ,1.1 Normal biological development and functioning ,Induced Pluripotent Stem Cells ,Biology ,bone marrow niche ,Bone and Bones ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Stroma ,Underpinning research ,Genetics ,medicine ,Animals ,Humans ,Epigenetics ,Progenitor cell ,Transplantation ,Bone Development ,Stem Cell Research - Induced Pluripotent Stem Cell ,Cartilage ,Mesenchymal Stem Cells ,Stem Cell Research ,Hematopoietic Stem Cells ,Mice, Inbred C57BL ,030104 developmental biology ,Musculoskeletal ,human skeletal stem cell ,Stromal Cells ,Transcriptome ,Developmental Biology - Abstract
Summary Stem cell regulation and hierarchical organization of human skeletal progenitors remain largely unexplored. Here, we report the isolation of a self-renewing and multipotent human skeletal stem cell (hSSC) that generates progenitors of bone, cartilage, and stroma, but not fat. Self-renewing and multipotent hSSCs are present in fetal and adult bones and can also be derived from BMP2-treated human adipose stroma (B-HAS) and induced pluripotent stem cells (iPSCs). Gene expression analysis of individual hSSCs reveals overall similarity between hSSCs obtained from different sources and partially explains skewed differentiation toward cartilage in fetal and iPSC-derived hSSCs. hSSCs undergo local expansion in response to acute skeletal injury. In addition, hSSC-derived stroma can maintain human hematopoietic stem cells (hHSCs) in serum-free culture conditions. Finally, we combine gene expression and epigenetic data of mouse skeletal stem cells (mSSCs) and hSSCs to identify evolutionarily conserved and divergent pathways driving SSC-mediated skeletogenesis. Video Abstract
- Published
- 2018
26. Muscle mitochondrial stress adaptation operates independently of endogenous FGF21 action
- Author
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Evert M. van Schothorst, Inge van der Stelt, Thomas H. Ambrosi, Mario Ost, Anna P. Kipp, Antonia Graja, Verena Coleman, Susanne Keipert, Susanne Klaus, Sebastian Ringel, Martin Jastroch, Tim J. Schulz, Jaap Keijer, and Anja Voigt
- Subjects
0301 basic medicine ,medicine.medical_specialty ,lcsh:Internal medicine ,FGF21 ,Physiology ,Mitochondrial disease ,White adipose tissue ,Biology ,03 medical and health sciences ,Internal medicine ,Mitochondrial unfolded protein response ,Myokine ,Brown adipose tissue ,medicine ,2.1 Biological and endogenous factors ,Integrated stress response ,Obesity ,Aetiology ,lcsh:RC31-1245 ,Molecular Biology ,Metabolic and endocrine ,Ecology, Evolution, Behavior and Systematics ,Nutrition ,VLAG ,Diabetes ,Skeletal muscle ,Muscle mitohormesis ,Cell Biology ,Stem Cell Research ,medicine.disease ,GDF15 ,Browning ,030104 developmental biology ,Endocrinology ,medicine.anatomical_structure ,Human and Animal Physiology ,WIAS ,Fysiologie van Mens en Dier ,Fgf21 ,Gdf15 ,Mitochondrial Disease ,Muscle Mitohormesis ,Stem Cell Research - Nonembryonic - Non-Human ,Original Article ,Animal Science and Zoology ,Biochemistry and Cell Biology - Abstract
Objective Fibroblast growth factor 21 (FGF21) was recently discovered as stress-induced myokine during mitochondrial disease and proposed as key metabolic mediator of the integrated stress response (ISR) presumably causing systemic metabolic improvements. Curiously, the precise cell-non-autonomous and cell-autonomous relevance of endogenous FGF21 action remained poorly understood. Methods We made use of the established UCP1 transgenic (TG) mouse, a model of metabolic perturbations made by a specific decrease in muscle mitochondrial efficiency through increased respiratory uncoupling and robust metabolic adaptation and muscle ISR-driven FGF21 induction. In a cross of TG with Fgf21-knockout (FGF21−/−) mice, we determined the functional role of FGF21 as a muscle stress-induced myokine under low and high fat feeding conditions. Results Here we uncovered that FGF21 signaling is dispensable for metabolic improvements evoked by compromised mitochondrial function in skeletal muscle. Strikingly, genetic ablation of FGF21 fully counteracted the cell-non-autonomous metabolic remodeling and browning of subcutaneous white adipose tissue (WAT), together with the reduction of circulating triglycerides and cholesterol. Brown adipose tissue activity was similar in all groups. Remarkably, we found that FGF21 played a negligible role in muscle mitochondrial stress-related improved obesity resistance, glycemic control and hepatic lipid homeostasis. Furthermore, the protective cell-autonomous muscle mitohormesis and metabolic stress adaptation, including an increased muscle proteostasis via mitochondrial unfolded protein response (UPRmt) and amino acid biosynthetic pathways did not require the presence of FGF21. Conclusions Here we demonstrate that although FGF21 drives WAT remodeling, the adaptive pseudo-starvation response under elevated muscle mitochondrial stress conditions operates independently of both WAT browning and FGF21 action. Thus, our findings challenge FGF21 as key metabolic mediator of the mitochondrial stress adaptation and powerful therapeutic target during muscle mitochondrial disease., Graphical abstract, Highlights • Muscle mitochondrial stress-induced browning of white adipose tissue fully requires FGF21. • Negligible role of myokine FGF21 on whole body metabolic adaptations. • Muscle mitohormesis and starvation-like response operates independently of FGF21 action.
- Published
- 2015
27. Distinct skeletal stem cell types orchestrate long bone skeletogenesis
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Thomas H Ambrosi, Rahul Sinha, Holly M Steininger, Malachia Y Hoover, Matthew P Murphy, Lauren S Koepke, Yuting Wang, Wan-Jin Lu, Maurizio Morri, Norma F Neff, Irving L Weissman, Michael T Longaker, and Charles KF Chan
- Subjects
bone ,skeletal stem cells ,diversity ,mesenchymal stromal cells ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
Skeletal stem and progenitor cell populations are crucial for bone physiology. Characterization of these cell types remains restricted to heterogenous bulk populations with limited information on whether they are unique or overlap with previously characterized cell types. Here we show, through comprehensive functional and single-cell transcriptomic analyses, that postnatal long bones of mice contain at least two types of bone progenitors with bona fide skeletal stem cell (SSC) characteristics. An early osteochondral SSC (ocSSC) facilitates long bone growth and repair, while a second type, a perivascular SSC (pvSSC), co-emerges with long bone marrow and contributes to shape the hematopoietic stem cell niche and regenerative demand. We establish that pvSSCs, but not ocSSCs, are the origin of bone marrow adipose tissue. Lastly, we also provide insight into residual SSC heterogeneity as well as potential crosstalk between the two spatially distinct cell populations. These findings comprehensively address previously unappreciated shortcomings of SSC research.
- Published
- 2021
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28. Delayed Union of a Diaphyseal Forearm Fracture Associated With Impaired Osteogenic Differentiation of Prospectively Isolated Human Skeletal Stem Cells
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L Henry Goodnough, Thomas H Ambrosi, Holly Steininger, Malcolm R DeBaun, Geoffrey D Abrams, Timothy R McAdams, Michael J Gardner, Charles KF Chan, and Julius A Bishop
- Subjects
BONE CELLS ,INJURY/FRACTURE HEALING ,ORTHOPEDICS ,STROMAL/STEM CELLS ,Orthopedic surgery ,RD701-811 ,Diseases of the musculoskeletal system ,RC925-935 - Abstract
ABSTRACT Delayed union or nonunion are relatively rare complications after fracture surgery, but when they do occur, they can result in substantial morbidity for the patient. In many cases, the etiology of impaired fracture healing is uncertain and attempts to determine the molecular basis for delayed union and nonunion formation have been limited. Prospectively isolating skeletal stem cells (SSCs) from fracture tissue samples at the time of surgical intervention represent a feasible methodology to determine a patient's biologic risk for compromised fracture healing. This report details a case in which functional in vitro readouts of SSCs derived from human fracture tissue at time of injury predicted a poor fracture healing outcome. This case suggests that it may be feasible to stratify a patient's fracture healing capacity and predict compromised fracture healing by prospectively isolating and analyzing SSCs during the index fracture surgery. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
- Published
- 2020
- Full Text
- View/download PDF
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