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Bhattacharyya ND, Kyaw W, McDonald MM, Dhenni R, Grootveld AK, Xiao Y, Chai R, Khoo WH, Danserau LC, Sergio CM, Timpson P, Lee WM, Croucher PI, Phan TG. Minimally invasive longitudinal intravital imaging of cellular dynamics in intact long bone. Nat Protoc 2023; 18:3856-3880. [PMID: 37857852 DOI: 10.1038/s41596-023-00894-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 07/28/2023] [Indexed: 10/21/2023]
Abstract
Intravital two-photon microscopy enables deep-tissue imaging at high temporospatial resolution in live animals. However, the endosteal bone compartment and underlying bone marrow pose unique challenges to optical imaging as light is absorbed, scattered and dispersed by thick mineralized bone matrix and the adipose-rich bone marrow. Early bone intravital imaging methods exploited gaps in the cranial sutures to bypass the need to penetrate through cortical bone. More recently, investigators have developed invasive methods to thin the cortical bone or implant imaging windows to image cellular dynamics in weight-bearing long bones. Here, we provide a step-by-step procedure for the preparation of animals for minimally invasive, nondestructive, longitudinal intravital imaging of the murine tibia. This method involves the use of mixed bone marrow radiation chimeras to unambiguously double-label osteoclasts and osteomorphs. The tibia is exposed by a simple skin incision and an imaging chamber constructed using thermoconductive T-putty. Imaging sessions up to 12 h long can be repeated over multiple timepoints to provide a longitudinal time window into the endosteal and marrow niches. The approach can be used to investigate cellular dynamics in bone remodeling, cancer cell life cycle and hematopoiesis, as well as long-lived humoral and cellular immunity. The procedure requires an hour to complete and is suitable for users with minimal prior expertise in small animal surgery.
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Affiliation(s)
- Nayan Deger Bhattacharyya
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Wunna Kyaw
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Michelle M McDonald
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Rama Dhenni
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Abigail K Grootveld
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Ya Xiao
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Ryan Chai
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Weng Hua Khoo
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Linda C Danserau
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
- ACRF INCITe Centre for Intravital Imaging of Niches for Cancer Immune Therapy, Sydney, New South Wales, Australia
| | - C Marcelo Sergio
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Paul Timpson
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
- ACRF INCITe Centre for Intravital Imaging of Niches for Cancer Immune Therapy, Sydney, New South Wales, Australia
| | - Woei Ming Lee
- ACRF INCITe Centre for Intravital Imaging of Niches for Cancer Immune Therapy, Sydney, New South Wales, Australia
- John Curtin School of Medical Research, Australian National University, Canberra, New South Wales, Australia
| | - Peter I Croucher
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
- ACRF INCITe Centre for Intravital Imaging of Niches for Cancer Immune Therapy, Sydney, New South Wales, Australia
| | - Tri Giang Phan
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia.
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia.
- ACRF INCITe Centre for Intravital Imaging of Niches for Cancer Immune Therapy, Sydney, New South Wales, Australia.
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Cunningham CJ, Choi RB, Bullock WA, Robling AG. Perspective: The current state of Cre driver mouse lines in skeletal research: Challenges and opportunities. Bone 2023; 170:116719. [PMID: 36868507 PMCID: PMC10087282 DOI: 10.1016/j.bone.2023.116719] [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] [Received: 12/28/2022] [Revised: 02/15/2023] [Accepted: 02/19/2023] [Indexed: 03/04/2023]
Abstract
The Cre/Lox system has revolutionized the ability of biomedical researchers to ask very specific questions about the function of individual genes in specific cell types at specific times during development and/or disease progression in a variety of animal models. This is true in the skeletal biology field, and numerous Cre driver lines have been created to foster conditional gene manipulation in specific subpopulations of bone cells. However, as our ability to scrutinize these models increases, an increasing number of issues have been identified with most driver lines. All existing skeletal Cre mouse models exhibit problems in one or more of the following three areas: (1) cell type specificity-avoiding Cre expression in unintended cell types; (2) Cre inducibility-improving the dynamic range for Cre in inducible models (negligible Cre activity before induction and high Cre activity after induction); and (3) Cre toxicity-reducing the unwanted biological effects of Cre (beyond loxP recombination) on cellular processes and tissue health. These issues are hampering progress in understanding the biology of skeletal disease and aging, and consequently, identification of reliable therapeutic opportunities. Skeletal Cre models have not advanced technologically in decades despite the availability of improved tools, including multi-promoter-driven expression of permissive or fragmented recombinases, new dimerization systems, and alternative forms of recombinases and DNA sequence targets. We review the current state of skeletal Cre driver lines, and highlight some of the successes, failures, and opportunities to improve fidelity in the skeleton, based on successes pioneered in other areas of biomedical science.
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Affiliation(s)
- Connor J Cunningham
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Roy B Choi
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Alexander G Robling
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA; Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA; Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, Indianapolis, IN, USA; Indiana Center for Musculoskeletal Health, Indianapolis, IN, USA.
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3
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Chai W, Hao W, Liu J, Han Z, Chang S, Cheng L, Sun M, Yan G, Liu Z, Liu Y, Zhang G, Xing L, Chen H, Liu P. Visualizing Cathepsin K-Cre Expression at the Single-Cell Level with GFP Reporters. JBMR Plus 2022; 7:e10706. [PMID: 36699636 PMCID: PMC9850439 DOI: 10.1002/jbm4.10706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 11/10/2022] [Accepted: 11/16/2022] [Indexed: 11/23/2022] Open
Abstract
The Cre/lox system is a fundamental tool for functional genomic studies, and a number of Cre lines have been generated to target genes of interest spatially and temporally in defined cells or tissues; this approach has greatly expanded our knowledge of gene functions. However, the limitations of this system have recently been recognized, and we must address the challenge of so-called nonspecific/off-target effects when a Cre line is utilized to investigate a gene of interest. For example, cathepsin K (Ctsk) has been used as a specific osteoclast marker, and Cre driven by its promoter is widely utilized for osteoclast investigations. However, Ctsk-Cre expression has recently been identified in other cell types, such as osteocytes, periosteal stem cells, and tenocytes. To better understand Ctsk-Cre expression and ensure appropriate use of this Cre line, we performed a comprehensive analysis of Ctsk-Cre expression at the single-cell level in major organs and tissues using two green fluorescent protein (GFP) reporters (ROSA nT-nG and ROSA tdT) and a tissue clearing technique in young and aging mice. The expression profile was further verified by immunofluorescence staining and droplet digital RT-PCR. The results demonstrate that Ctsk-Cre is expressed not only in osteoclasts but also at various levels in osteoblast lineage cells and other major organs/tissues, particularly in the brain, kidney, pancreas, and blood vessels. Furthermore, Ctsk-Cre expression increases markedly in the bone marrow, skeletal muscle, and intervertebral discs in aging mice. These data will be valuable for accurately interpreting data obtained from in vivo studies using Ctsk-Cre mice to avoid potentially misleading conclusions. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Wenhuan Chai
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Weiwei Hao
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Jintao Liu
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Zhenglin Han
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Shiyu Chang
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Liben Cheng
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Mingxin Sun
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Guofang Yan
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Zemin Liu
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Yin Liu
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Guodong Zhang
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Li Xing
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Hongqian Chen
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
| | - Peng Liu
- Laboratory of Bone & Adipose BiologyShanxi Medical UniversityTaiyuanChina
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Yu J, Schilling L, Eller T, Canalis E. Hairy and enhancer of split 1 is a primary effector of NOTCH2 signaling and induces osteoclast differentiation and function. J Biol Chem 2021; 297:101376. [PMID: 34742737 PMCID: PMC8633688 DOI: 10.1016/j.jbc.2021.101376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 12/12/2022] Open
Abstract
Notch2tm1.1Ecan mice, which harbor a mutation replicating that found in Hajdu–Cheney syndrome, exhibit marked osteopenia because of increased osteoclast number and bone resorption. Hairy and enhancer of split 1 (HES1) is a Notch target gene and a transcriptional modulator that determines osteoclast cell fate decisions. Transcript levels of Hes1 increase in Notch2tm1.1Ecan bone marrow–derived macrophages (BMMs) as they mature into osteoclasts, suggesting a role in osteoclastogenesis. To determine whether HES1 is responsible for the phenotype of Notch2tm1.1Ecan mice and the skeletal manifestations of Hajdu–Cheney syndrome, Hes1 was inactivated in Ctsk-expressing cells from Notch2tm1.1Ecan mice. Ctsk encodes the protease cathepsin K, which is expressed preferentially by osteoclasts. We found that the osteopenia of Notch2tm1.1Ecan mice was ameliorated, and the enhanced osteoclastogenesis was reversed in the context of the Hes1 inactivation. Microcomputed tomography revealed that the downregulation of Hes1 in Ctsk-expressing cells led to increased bone volume/total volume in female mice. In addition, cultures of BMMs from CtskCre/WT;Hes1Δ/Δ mice displayed a decrease in osteoclast number and size and decreased bone-resorbing capacity. Moreover, activation of HES1 in Ctsk-expressing cells led to osteopenia and enhanced osteoclast number, size, and bone resorptive capacity in BMM cultures. Osteoclast phenotypes and RNA-Seq of cells in which HES1 was activated revealed that HES1 modulates cell–cell fusion and bone-resorbing capacity by supporting sealing zone formation. In conclusion, we demonstrate that HES1 is mechanistically relevant to the skeletal manifestation of Notch2tm1.1Ecan mice and is a novel determinant of osteoclast differentiation and function.
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Affiliation(s)
- Jungeun Yu
- Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, USA; UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, USA
| | - Lauren Schilling
- UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, USA
| | - Tabitha Eller
- UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, USA
| | - Ernesto Canalis
- Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, USA; UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, USA; Department of Medicine, UConn Health, Farmington, Connecticut, USA.
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5
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Couasnay G, Madel MB, Lim J, Lee B, Elefteriou F. Sites of Cre-recombinase activity in mouse lines targeting skeletal cells. J Bone Miner Res 2021; 36:1661-1679. [PMID: 34278610 DOI: 10.1002/jbmr.4415] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/12/2021] [Accepted: 07/15/2021] [Indexed: 12/22/2022]
Abstract
The Cre/Lox system is a powerful tool in the biologist's toolbox, allowing loss-of-function and gain-of-function studies, as well as lineage tracing, through gene recombination in a tissue-specific and inducible manner. Evidence indicates, however, that Cre transgenic lines have a far more nuanced and broader pattern of Cre activity than initially thought, exhibiting "off-target" activity in tissues/cells other than the ones they were originally designed to target. With the goal of facilitating the comparison and selection of optimal Cre lines to be used for the study of gene function, we have summarized in a single manuscript the major sites and timing of Cre activity of the main Cre lines available to target bone mesenchymal stem cells, chondrocytes, osteoblasts, osteocytes, tenocytes, and osteoclasts, along with their reported sites of "off-target" Cre activity. We also discuss characteristics, advantages, and limitations of these Cre lines for users to avoid common risks related to overinterpretation or misinterpretation based on the assumption of strict cell-type specificity or unaccounted effect of the Cre transgene or Cre inducers. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Greig Couasnay
- Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA
| | | | - Joohyun Lim
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Florent Elefteriou
- Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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6
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Phlpp1 is induced by estrogen in osteoclasts and its loss in Ctsk-expressing cells does not protect against ovariectomy-induced bone loss. PLoS One 2021; 16:e0251732. [PMID: 34143773 PMCID: PMC8213150 DOI: 10.1371/journal.pone.0251732] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 05/02/2021] [Indexed: 11/19/2022] Open
Abstract
Prior studies demonstrated that deletion of the protein phosphatase Phlpp1 in Ctsk-Cre expressing cells enhances bone mass, characterized by diminished osteoclast activity and increased coupling to bone formation. Due to non-specific expression of Ctsk-Cre, the definitive mechanism for this observation was unclear. To further define the role of bone resorbing osteoclasts, we performed ovariectomy (Ovx) and Sham surgeries on Phlpp1 cKOCtsk and WT mice. Micro-CT analyses confirmed enhanced bone mass of Phlpp1 cKOCtsk Sham females. In contrast, Ovx induced bone loss in both groups, with no difference between Phlpp1 cKOCtsk and WT mice. Histomorphometry demonstrated that Ovx mice lacked differences in osteoclasts per bone surface, suggesting that estradiol (E2) is required for Phlpp1 deficiency to have an effect. We performed high throughput unbiased transcriptional profiling of Phlpp1 cKOCtsk osteoclasts and identified 290 differentially expressed genes. By cross-referencing these differentially expressed genes with all estrogen response element (ERE) containing genes, we identified IGFBP4 as potential estrogen-dependent target of Phlpp1. E2 induced PHLPP1 expression, but reduced IGFBP4 levels. Moreover, genetic deletion or chemical inhibition of Phlpp1 was correlated with IGFBP4 levels. We then assessed IGFBP4 expression by osteoclasts in vivo within intact 12-week-old females. Modest IGFBP4 immunohistochemical staining of TRAP+ osteoclasts within WT females was observed. In contrast, TRAP+ bone lining cells within intact Phlpp1 cKOCtsk females robustly expressed IGFBP4, but levels were diminished within TRAP+ bone lining cells following Ovx. These results demonstrate that effects of Phlpp1 conditional deficiency are lost following Ovx, potentially due to estrogen-dependent regulation of IGFBP4.
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7
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Molstad DHH, Mattson AM, Begun DL, Westendorf JJ, Bradley EW. Hdac3 regulates bone modeling by suppressing osteoclast responsiveness to RANKL. J Biol Chem 2021; 295:17713-17723. [PMID: 33454009 DOI: 10.1074/jbc.ra120.013573] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 09/30/2020] [Indexed: 11/06/2022] Open
Abstract
Hdac3 is a lysine deacetylase that removes acetyl groups from histones and additional proteins. Although Hdac3 functions within mesenchymal lineage skeletal cells are defined, little is known about Hdac3 activities in bone-resorbing osteoclasts. In this study we conditionally deleted Hdac3 within Ctsk-expressing cells and examined the effects on bone modeling and osteoclast differentiation in mice. Hdac3 deficiency reduced femur and tibia periosteal circumference and increased cortical periosteal osteoclast number. Trabecular bone was likewise reduced and was accompanied by increased osteoclast number per trabecular bone surface. We previously showed that Hdac3 deacetylates the p65 subunit of the NF-κB transcriptional complex to decrease DNA-binding and transcriptional activity. Hdac3-deficient osteoclasts demonstrate increased K310 NF-κB acetylation and NF-κB transcriptional activity. Hdac3-deficient osteoclast lineage cells were hyper-responsive to RANKL and showed elevated ex vivo osteoclast number and size and enhanced bone resorption in pit formation assays. Osteoclast-directed Hdac3 deficiency decreased cortical and trabecular bone mass parameters, suggesting that Hdac3 regulates coupling of bone resorption and bone formation. We surveyed a panel of osteoclast-derived coupling factors and found that Hdac3 suppression diminished sphingosine-1-phosphate production. Osteoclast-derived sphingosine-1-phosphate acts in paracrine to promote bone mineralization. Mineralization of WT bone marrow stromal cells cultured with conditioned medium from Hdac3-deficient osteoclasts was markedly reduced. Expression of alkaline phosphatase, type 1a1 collagen, and osteocalcin was also suppressed, but no change in Runx2 expression was observed. Our results demonstrate that Hdac3 controls bone modeling by suppressing osteoclast lineage cell responsiveness to RANKL and coupling to bone formation.
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Affiliation(s)
- David H H Molstad
- Department of Orthopedics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Anna M Mattson
- Departments of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Dana L Begun
- Departments of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Jennifer J Westendorf
- Departments of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA; Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Elizabeth W Bradley
- Department of Orthopedics, University of Minnesota, Minneapolis, Minnesota, USA; Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, USA.
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8
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Dodington DW, Yumol JL, Yang J, Pollock-Tahiri E, Sivasubramaniyam T, Sacco SM, Schroer SA, Li YE, Le H, Ward WE, Woo M. JAK2-IGF1 axis in osteoclasts regulates postnatal growth in mice. JCI Insight 2021; 6:137045. [PMID: 33682794 PMCID: PMC8021113 DOI: 10.1172/jci.insight.137045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 01/20/2021] [Indexed: 11/30/2022] Open
Abstract
Osteoclasts are specialized cells of the hematopoietic lineage that are responsible for bone resorption and play a critical role in musculoskeletal disease. JAK2 is a key mediator of cytokine and growth factor signaling; however, its role in osteoclasts in vivo has yet to be investigated. To elucidate the role of JAK2 in osteoclasts, we generated an osteoclast-specific JAK2-KO (Oc-JAK2-KO) mouse using the Cre/Lox-P system. Oc-JAK2-KO mice demonstrated marked postnatal growth restriction; however, this was not associated with significant changes in bone density, microarchitecture, or strength, indicating that the observed phenotype was not due to alterations in canonical osteoclast function. Interestingly, Oc-JAK2-KO mice had reduced osteoclast-specific expression of IGF1, suggesting a role for osteoclast-derived IGF1 in determination of body size. To directly assess the role of osteoclast-derived IGF1, we generated an osteoclast-specific IGF1-KO mouse, which showed a similar growth-restricted phenotype. Lastly, overexpression of circulating IGF1 by human transgene rescued the growth defects in Oc-JAK2-KO mice, in keeping with a causal role of IGF1 in these models. Together, our data show a potentially novel role for Oc-JAK2 and IGF1 in the determination of body size, which is independent of osteoclast resorptive function.
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Affiliation(s)
- David W. Dodington
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | | | - Jiaqi Yang
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Evan Pollock-Tahiri
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Tharini Sivasubramaniyam
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | | | - Stephanie A. Schroer
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Yujin E. Li
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Helen Le
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Wendy E. Ward
- Department of Kinesiology and
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Minna Woo
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Institute of Medical Science and Department of Immunology and
- Division of Endocrinology and Metabolism, Department of Medicine, University Health Network/Sinai Health System, University of Toronto, Toronto, Ontario, Canada
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9
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McDonald MM, Khoo WH, Ng PY, Xiao Y, Zamerli J, Thatcher P, Kyaw W, Pathmanandavel K, Grootveld AK, Moran I, Butt D, Nguyen A, Corr A, Warren S, Biro M, Butterfield NC, Guilfoyle SE, Komla-Ebri D, Dack MRG, Dewhurst HF, Logan JG, Li Y, Mohanty ST, Byrne N, Terry RL, Simic MK, Chai R, Quinn JMW, Youlten SE, Pettitt JA, Abi-Hanna D, Jain R, Weninger W, Lundberg M, Sun S, Ebetino FH, Timpson P, Lee WM, Baldock PA, Rogers MJ, Brink R, Williams GR, Bassett JHD, Kemp JP, Pavlos NJ, Croucher PI, Phan TG. Osteoclasts recycle via osteomorphs during RANKL-stimulated bone resorption. Cell 2021; 184:1330-1347.e13. [PMID: 33636130 PMCID: PMC7938889 DOI: 10.1016/j.cell.2021.02.002] [Citation(s) in RCA: 153] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 11/20/2020] [Accepted: 02/01/2021] [Indexed: 02/02/2023]
Abstract
Osteoclasts are large multinucleated bone-resorbing cells formed by the fusion of monocyte/macrophage-derived precursors that are thought to undergo apoptosis once resorption is complete. Here, by intravital imaging, we reveal that RANKL-stimulated osteoclasts have an alternative cell fate in which they fission into daughter cells called osteomorphs. Inhibiting RANKL blocked this cellular recycling and resulted in osteomorph accumulation. Single-cell RNA sequencing showed that osteomorphs are transcriptionally distinct from osteoclasts and macrophages and express a number of non-canonical osteoclast genes that are associated with structural and functional bone phenotypes when deleted in mice. Furthermore, genetic variation in human orthologs of osteomorph genes causes monogenic skeletal disorders and associates with bone mineral density, a polygenetic skeletal trait. Thus, osteoclasts recycle via osteomorphs, a cell type involved in the regulation of bone resorption that may be targeted for the treatment of skeletal diseases.
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Affiliation(s)
- Michelle M McDonald
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Weng Hua Khoo
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Pei Ying Ng
- Bone Biology & Disease Laboratory, School of Biomedical Sciences, University of Western Australia, Nedlands, WA, Australia
| | - Ya Xiao
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Jad Zamerli
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Peter Thatcher
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Wunna Kyaw
- Immunology Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | | | - Abigail K Grootveld
- Immunology Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Imogen Moran
- Immunology Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Danyal Butt
- Immunology Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Akira Nguyen
- Immunology Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Alexander Corr
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Sean Warren
- Cancer, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Maté Biro
- EMBL Australia, Single Molecule Science Node, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Natalie C Butterfield
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion & Reproduction, Imperial College London, London, UK
| | - Siobhan E Guilfoyle
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion & Reproduction, Imperial College London, London, UK
| | - Davide Komla-Ebri
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion & Reproduction, Imperial College London, London, UK
| | - Michael R G Dack
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion & Reproduction, Imperial College London, London, UK
| | - Hannah F Dewhurst
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion & Reproduction, Imperial College London, London, UK
| | - John G Logan
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion & Reproduction, Imperial College London, London, UK
| | - Yongxiao Li
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Sindhu T Mohanty
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Niall Byrne
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Rachael L Terry
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Marija K Simic
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Ryan Chai
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Julian M W Quinn
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Scott E Youlten
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Jessica A Pettitt
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - David Abi-Hanna
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Rohit Jain
- Immune Imaging Program, Centenary Institute, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Wolfgang Weninger
- Immune Imaging Program, Centenary Institute, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Mischa Lundberg
- The University of Queensland Diamantina Institute, University of Queensland, Woolloongabba, QLD, Australia; Transformational Bioinformatics, Commonwealth Scientific and Industrial Research Organisation, Sydney, NSW, Australia
| | | | | | - Paul Timpson
- Cancer, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Woei Ming Lee
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Paul A Baldock
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Michael J Rogers
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Robert Brink
- St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia; Immunology Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Graham R Williams
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion & Reproduction, Imperial College London, London, UK
| | - J H Duncan Bassett
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion & Reproduction, Imperial College London, London, UK
| | - John P Kemp
- The University of Queensland Diamantina Institute, University of Queensland, Woolloongabba, QLD, Australia; Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Nathan J Pavlos
- Bone Biology & Disease Laboratory, School of Biomedical Sciences, University of Western Australia, Nedlands, WA, Australia
| | - Peter I Croucher
- Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia.
| | - Tri Giang Phan
- St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia; Immunology Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia.
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10
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Selective deletion of the receptor for CSF1, c-fms, in osteoclasts results in a high bone mass phenotype, smaller osteoclasts in vivo and an impaired response to an anabolic PTH regimen. PLoS One 2021; 16:e0247199. [PMID: 33607650 PMCID: PMC7895546 DOI: 10.1371/journal.pone.0247199] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/02/2021] [Indexed: 11/26/2022] Open
Abstract
The receptor for Colony Stimulating Factor 1 (CSF1), c-fms, is highly expressed on mature osteoclasts suggesting a role for this cytokine in regulating the function of these cells. Consistent with this idea, in vitro studies have documented a variety of effects of CSF1 in mature osteoclasts. To better define the role of CSF1 in these cells, we conditionally deleted c-fms in osteoclasts (c-fms-OC-/-) by crossing c-fmsflox/flox mice with mice expressing Cre under the control of the cathepsin K promoter. The c-fms-OC-/- mice were of normal weight and had normal tooth eruption. However, when quantified by DXA, bone mass was significantly higher in the spine and femur of female knock out mice and in the femurs of male knock out mice. MicroCT analyses of femurs showed that female c-fms-OC-/- mice had significantly increased trabecular bone mass with a similar trend in males and both sexes demonstrated significantly increased trabecular number and reduced trabecular spacing. Histomorphometric analysis of the femoral trabecular bone compartment demonstrated a trend towards increased numbers of osteoclasts, +26% in Noc/BPm and +22% in OcS/BS in the k/o animals but this change was not significant. However, when the cellular volume of osteoclasts was quantified, the c-fms-OC-/- cells were found to be significantly smaller than controls. Mature osteoclasts show a marked spreading response when exposed to CSF1 in a non-gradient fashion. However, osteoclasts freshly isolated from c-fms-OC-/- mice had a near complete abrogation of this response. C-fms-OC-/- mice treated with (1–34)hPTH 80 ng/kg/d in single daily subcutaneous doses for 29 days showed an attenuated anabolic response in trabecular bone compared to wild-type animals. Taken together, these data indicate an important non-redundant role for c-fms in regulating mature osteoclast function in vivo.
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11
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Abstract
The Cre-LoxP technology permits gene ablation in specific cell lineages, at chosen differentiation stages of this lineage and in an inducible manner. It has allowed tremendous advances in our understanding of skeleton biology and related pathophysiological mechanisms, through the generation of loss/gain of function or cell tracing experiments based on the creation of an expanding toolbox of transgenic mice expressing the Cre recombinase in skeletal stem cells, chondrocytes, osteoblasts, or osteoclasts. In this chapter, we provide an overview of the different Cre-LoxP systems and Cre mouse lines used in the bone field, we discuss their advantages, limitations, and we outline best practices to interpret results obtained from the use of Cre mice.
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Affiliation(s)
- Florent Elefteriou
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
- Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA.
| | - Greig Couasnay
- Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA
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12
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Li S, He T, Wu D, Zhang L, Chen R, Liu B, Yuan J, Tickner J, Qin A, Xu J, Rong L. Conditional Knockout of PKC-δ in Osteoclasts Favors Bone Mass Accrual in Males Due to Decreased Osteoclast Function. Front Cell Dev Biol 2020; 8:450. [PMID: 32582715 PMCID: PMC7295979 DOI: 10.3389/fcell.2020.00450] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/13/2020] [Indexed: 02/06/2023] Open
Abstract
Protein kinase C delta (PKC-δ) functions as an important regulator in bone metabolism. However, the precise involvement of PKC-δ in the regulation of osteoclasts remains elusive. We generated an osteoclast specific PKC-δ knockout mouse strain to investigate the function of PKC-δ in osteoclast biology. Bone phenotype was investigated using microcomputed tomography. Osteoclast and osteoblast parameters were assessed using bone histomorphometry, and analysis of osteoclast formation and function with osteoclastogensis and hydroxyapatite resorption assays. The molecular mechanisms by which PKC-δ regulated osteoclast function were dissected by Western Blotting, TUNEL assay, transfection and transcriptome sequencing. We found that ablation of PKC-δ in osteoclasts resulted in an increase in trabecular and cortical bone volume in male mice, however, the bone mass phenotype was not observed in female mice. This was accompanied by decreased osteoclast number and surface, and Cathepsin-K protein levels in vivo, as well as decreased osteoclast formation and resorption in vitro in a male-specific manner. PKC-δ regulated androgen receptor transcription by binding to its promoter, moreover, PKC-δ conditional knockout did not increase osteoclast apoptosis but increased MAPK signaling and enhanced androgen receptor transcription and expression, finally leding to significant alterations in gene expression and signaling changes related to extracellular matrix proteins specifically in male mice. In conclusion, PKC-δ plays an important role in osteoclast formation and function in a male-specific manner. Our work reveals a previously unknown target for treatment of gender-related bone diseases.
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Affiliation(s)
- Shangfu Li
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, Guangzhou, China.,Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, Guangzhou, China
| | - Tianwei He
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, Guangzhou, China.,Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, Guangzhou, China
| | - Depeng Wu
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, Guangzhou, China.,Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, Guangzhou, China
| | - Liangming Zhang
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, Guangzhou, China.,Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, Guangzhou, China
| | - Ruiqiang Chen
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, Guangzhou, China.,Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, Guangzhou, China
| | - Bin Liu
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, Guangzhou, China.,Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, Guangzhou, China
| | - Jinbo Yuan
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Jennifer Tickner
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - An Qin
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiake Xu
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Limin Rong
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, Guangzhou, China.,Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, Guangzhou, China
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13
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Kohara Y, Haraguchi R, Kitazawa R, Kitazawa S. Knockdown of Lrp1 in RAW264 cells inhibits osteoclast differentiation and osteoclast-osteoblast interactions in vitro. Biochem Biophys Res Commun 2020; 523:961-965. [PMID: 31964526 DOI: 10.1016/j.bbrc.2020.01.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 01/11/2020] [Indexed: 12/28/2022]
Abstract
Low density lipoprotein receptor-related protein 1 (LRP1), a multifunctional cell surface protein, is expressed in bone marrow-derived macrophages. While LRP1 is thought to be a suppressor of osteoclast differentiation at late stages, its function at early stages remains unclear. Here we demonstrate that Lrp1 stable knockdown by lentiviral short hairpin RNA in macrophage cell line RAW264 cells inhibited RANKL-induced osteoclast formation and osteoclastic master transcription factor Nfatc1 mRNA expression as assessed by quantitative RT-PCR. Furthermore, knockdown of the Lrp1 gene suppressed not only differentiation, but also proliferation, and inhibitory effects on osteoblastic ALP activity by osteoclast-derived humoral factors. Thus, we propose that LRP1 in macrophages is required for both differentiation into osteoclasts and osteoclast-osteoblast interactions.
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Affiliation(s)
- Yukihiro Kohara
- Department of Molecular Pathology, Ehime University Graduate School of Medicine, Shitsukawa, Toon City, Ehime, 791-0295, Japan.
| | - Ryuma Haraguchi
- Department of Molecular Pathology, Ehime University Graduate School of Medicine, Shitsukawa, Toon City, Ehime, 791-0295, Japan
| | - Riko Kitazawa
- Department of Molecular Pathology, Ehime University Graduate School of Medicine, Shitsukawa, Toon City, Ehime, 791-0295, Japan; Division of Diagnostic Pathology, Ehime University Hospital, Shitsukawa, Toon City, Ehime, 791-0295, Japan
| | - Sohei Kitazawa
- Department of Molecular Pathology, Ehime University Graduate School of Medicine, Shitsukawa, Toon City, Ehime, 791-0295, Japan
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14
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Roberts JL, Liu G, Paglia DN, Kinter CW, Fernandes LM, Lorenzo J, Hansen MF, Arif A, Drissi H. Deletion of
Wnt5a
in osteoclasts results in bone loss through decreased bone formation. Ann N Y Acad Sci 2020; 1463:45-59. [DOI: 10.1111/nyas.14293] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/25/2019] [Accepted: 12/04/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Joseph L. Roberts
- Department of Orthopaedics Emory University School of Medicine Atlanta Georgia
| | - Guanglu Liu
- Department of Orthopaedics Emory University School of Medicine Atlanta Georgia
| | - David N. Paglia
- Department of Orthopaedics, New Jersey Medical School Rutgers University Newark New Jersey
| | | | | | - Joseph Lorenzo
- Department of Medicine and Department of Orthopaedic Surgery University of Connecticut Health Farmington Connecticut
| | - Marc F. Hansen
- Center for Molecular Medicine University of Connecticut Health Farmington Connecticut
| | - Abul Arif
- Department of Orthopaedics Emory University School of Medicine Atlanta Georgia
| | - Hicham Drissi
- Department of Orthopaedics Emory University School of Medicine Atlanta Georgia
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15
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Mattson AM, Begun DL, Molstad DHH, Meyer MA, Oursler MJ, Westendorf JJ, Bradley EW. Deficiency in the phosphatase PHLPP1 suppresses osteoclast-mediated bone resorption and enhances bone formation in mice. J Biol Chem 2019; 294:11772-11784. [PMID: 31189651 DOI: 10.1074/jbc.ra119.007660] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/24/2019] [Indexed: 12/21/2022] Open
Abstract
Enhanced osteoclast-mediated bone resorption and diminished formation may promote bone loss. Pleckstrin homology (PH) domain and leucine-rich repeat protein phosphatase 1 (Phlpp1) regulates protein kinase C (PKC) and other proteins in the control of bone mass. Germline Phlpp1 deficiency reduces bone volume, but the mechanisms remain unknown. Here, we found that conditional Phlpp1 deletion in murine osteoclasts increases their numbers, but also enhances bone mass. Despite elevating osteoclasts, Phlpp1 deficiency did not increase serum markers of bone resorption, but elevated serum markers of bone formation. These results suggest that Phlpp1 suppresses osteoclast formation and production of paracrine factors controlling osteoblast activity. Phlpp1 deficiency elevated osteoclast numbers and size in ex vivo osteoclastogenesis assays, accompanied by enhanced expression of proto-oncogene C-Fms (C-Fms) and hyper-responsiveness to macrophage colony-stimulating factor (M-CSF) in bone marrow macrophages. Although Phlpp1 deficiency increased TRAP+ cell numbers, it suppressed actin-ring formation and bone resorption in these assays. We observed that Phlpp1 deficiency increases activity of PKCζ, a PKC isoform controlling cell polarity, and that addition of a PKCζ pseudosubstrate restores osteoclastogenesis and bone resorption of Phlpp1-deficient osteoclasts. Moreover, Phlpp1 deficiency increased expression of the bone-coupling factor collagen triple helix repeat-containing 1 (Cthrc1). Conditioned growth medium derived from Phlpp1-deficient osteoclasts enhanced mineralization of ex vivo osteoblast cultures, an effect that was abrogated by Cthrc1 knockdown. In summary, Phlpp1 critically regulates osteoclast numbers, and Phlpp1 deficiency enhances bone mass despite higher osteoclast numbers because it apparently disrupts PKCζ activity, cell polarity, and bone resorption and increases secretion of bone-forming Cthrc1.
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Affiliation(s)
- Anna M Mattson
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - Dana L Begun
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - David H H Molstad
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - Margaret A Meyer
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - Merry Jo Oursler
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55901.,Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55901.,Kogod Center on Aging, Mayo Clinic, Rochester, Minnesota 55901
| | - Jennifer J Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55901
| | - Elizabeth W Bradley
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901 .,Department of Biomedical Engineering and Physiology, Mayo Clinic, Rochester, Minnesota 55901
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16
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Abstract
PURPOSE Transgenic Cre lines are a valuable tool for conditionally inactivating or activating genes to understand their function. Here, we provide an overview of Cre transgenic models used for studying gene function in bone cells and discuss their advantages and limitations, with particular emphasis on Cre lines used for studying osteocyte and osteoclast function. RECENT FINDINGS Recent studies have shown that many bone cell-targeted Cre models are not as specific as originally thought. To ensure accurate data interpretation, it is important for investigators to test for unexpected recombination events due to transient expression of Cre recombinase during development or in precursor cells and to be aware of the potential for germ line recombination of targeted genes as well as the potential for unexpected phenotypes due to the Cre transgene. Although many of the bone-targeted Cre-deleter strains are imperfect and each model has its own limitations, their careful use will continue to provide key advances in our understanding of bone cell function in health and disease.
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Affiliation(s)
- Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, 650 E. 25th Street, Kansas, MO, 64108, USA.
| | - Yixia Xie
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, 650 E. 25th Street, Kansas, MO, 64108, USA
| | - Lora A Shiflett
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, 650 E. 25th Street, Kansas, MO, 64108, USA
| | - Yasuyoshi Ueki
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, 650 E. 25th Street, Kansas, MO, 64108, USA
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17
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Huynh H, Wan Y. mTORC1 impedes osteoclast differentiation via calcineurin and NFATc1. Commun Biol 2018; 1:29. [PMID: 30271915 PMCID: PMC6123628 DOI: 10.1038/s42003-018-0028-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 03/06/2018] [Indexed: 12/26/2022] Open
Abstract
Rapamycins are immunosuppressant and anti-cancer drugs that inhibit the kinase mTOR. Clinically, they often cause bone pain, bone necrosis, and high bone turnover, yet the mechanisms are unclear. Here we show that mTORC1 activity is high in osteoclast precursors but downregulated upon RANKL treatment. Loss-of-function genetic models reveal that while early Raptor deletion in hematopoietic stem cells blunts osteoclastogenesis due to compromised proliferation/survival, late Raptor deletion in osteoclast precursors instead augments osteoclastogenesis. Gain-of-function genetic models by TSC1 deletion in HSCs or osteoclast precursors cause constitutive mTORC1 activation, impairing osteoclastogenesis. Pharmacologically, rapamycin treatment at low but clinically relevant doses exacerbates osteoclast differentiation and bone resorption, leading to bone loss. Mechanistically, RANKL inactivates mTORC1 via calcineurin-mediated mTORC1 dephosphorylation, consequently activating NFATc1 by reducing mTORC1-mediated NFATc1 phosphorylation. These findings uncover biphasic roles of mTORC1 in osteoclastogenesis, dosage-dependent effects of rapamycin on bone, and a previously unrecognized calcineurin-mTORC1-NFATc1 phosphorylation-regulatory signaling cascade.
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Affiliation(s)
- HoangDinh Huynh
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Yihong Wan
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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18
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Nakamichi Y, Udagawa N, Suda T, Takahashi N. Mechanisms involved in bone resorption regulated by vitamin D. J Steroid Biochem Mol Biol 2018; 177:70-76. [PMID: 29146302 DOI: 10.1016/j.jsbmb.2017.11.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/26/2017] [Accepted: 11/12/2017] [Indexed: 12/31/2022]
Abstract
Active forms of vitamin D enhance osteoclastogenesis in vitro and in vivo through the vitamin D receptor (VDR) in osteoblast-lineage cells consisting of osteoblasts and osteocytes. This pro-resorptive activity was evident basically with higher concentrations of active vitamin D than those expected in physiological conditions. Nevertheless, vitamin D compounds have been used in Japan for treating osteoporosis to increase bone mineral density (BMD). Of note, the increase in BMD by long-term treatment with pharmacological (=near-physiological) doses of vitamin D compounds was caused by the suppression of bone resorption. Therefore, whether vitamin D expresses pro-resorptive or anti-resorptive properties seems to be dependent on the treatment protocols. We established osteoblast lineage-specific and osteoclast-specific VDR conditional knockout (cKO) mice using Osterix-Cre transgenic mice and Cathepsin K-Cre knock-in mice, respectively. According to our observation using these cKO mouse lines, neither VDR in osteoblast-lineage cells nor that in osteoclasts played important roles for osteoclastogenesis and bone resorption at homeostasis. However, using our cKO lines, we observed that VDR in osteoblast-lineage cells, but not osteoclasts, was involved in the anti-resorptive properties of pharmacological doses of vitamin D compounds in vivo. Two different osteoblast-lineage VDR cKO mouse lines were reported. One is a VDR cKO mouse line using alpha 1, type I collagen (Col1a1)-Cre transgenic mice (here we call Col1a1-VDR-cKO mice) and the other is that using dentin matrix protein 1 (Dmp1)-Cre transgenic mice (Dmp1-VDR-cKO mice). Col1a1-VDR-cKO mice exhibited slightly increased bone mass due to lowered bone resorption. In contrast, Dmp1-VDR-cKO mice exhibited no difference in BMD in agreement with our results regarding Ob-VDR-cKO mice. Here we discuss contradictory results and multiple modes of actions of vitamin D in bone resorption in detail. (279 words).
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Affiliation(s)
- Yuko Nakamichi
- Institute for Oral Science, Matsumoto Dental University, Shiojiri, Nagano 399-0781, Japan.
| | - Nobuyuki Udagawa
- Department of Biochemistry, Matsumoto Dental University, Shiojiri, Nagano 399-0781, Japan
| | - Tatsuo Suda
- Research Center for Genomic Medicine, Saitama Medical University, Saitama 350-1241, Japan
| | - Naoyuki Takahashi
- Institute for Oral Science, Matsumoto Dental University, Shiojiri, Nagano 399-0781, Japan
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19
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Okamoto K, Nakashima T, Shinohara M, Negishi-Koga T, Komatsu N, Terashima A, Sawa S, Nitta T, Takayanagi H. Osteoimmunology: The Conceptual Framework Unifying the Immune and Skeletal Systems. Physiol Rev 2017; 97:1295-1349. [DOI: 10.1152/physrev.00036.2016] [Citation(s) in RCA: 241] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 03/29/2017] [Accepted: 04/04/2017] [Indexed: 12/13/2022] Open
Abstract
The immune and skeletal systems share a variety of molecules, including cytokines, chemokines, hormones, receptors, and transcription factors. Bone cells interact with immune cells under physiological and pathological conditions. Osteoimmunology was created as a new interdisciplinary field in large part to highlight the shared molecules and reciprocal interactions between the two systems in both heath and disease. Receptor activator of NF-κB ligand (RANKL) plays an essential role not only in the development of immune organs and bones, but also in autoimmune diseases affecting bone, thus effectively comprising the molecule that links the two systems. Here we review the function, gene regulation, and signal transduction of osteoimmune molecules, including RANKL, in the context of osteoclastogenesis as well as multiple other regulatory functions. Osteoimmunology has become indispensable for understanding the pathogenesis of a number of diseases such as rheumatoid arthritis (RA). We review the various osteoimmune pathologies, including the bone destruction in RA, in which pathogenic helper T cell subsets [such as IL-17-expressing helper T (Th17) cells] induce bone erosion through aberrant RANKL expression. We also focus on cellular interactions and the identification of the communication factors in the bone marrow, discussing the contribution of bone cells to the maintenance and regulation of hematopoietic stem and progenitors cells. Thus the time has come for a basic reappraisal of the framework for understanding both the immune and bone systems. The concept of a unified osteoimmune system will be absolutely indispensable for basic and translational approaches to diseases related to bone and/or the immune system.
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Affiliation(s)
- Kazuo Okamoto
- Department of Osteoimmunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Tomoki Nakashima
- Department of Osteoimmunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Masahiro Shinohara
- Department of Osteoimmunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Takako Negishi-Koga
- Department of Osteoimmunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Noriko Komatsu
- Department of Osteoimmunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Asuka Terashima
- Department of Osteoimmunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Shinichiro Sawa
- Department of Osteoimmunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Takeshi Nitta
- Department of Osteoimmunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Hiroshi Takayanagi
- Department of Osteoimmunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
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Jin YR, Stohn JP, Wang Q, Nagano K, Baron R, Bouxsein ML, Rosen CJ, Adarichev VA, Lindner V. Inhibition of osteoclast differentiation and collagen antibody-induced arthritis by CTHRC1. Bone 2017; 97:153-167. [PMID: 28115279 PMCID: PMC6746321 DOI: 10.1016/j.bone.2017.01.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/05/2017] [Accepted: 01/20/2017] [Indexed: 01/12/2023]
Abstract
Collagen triple helix repeat-containing1 (Cthrc1) has previously been implicated in osteogenic differentiation and positive regulation of bone mass, however, the underlying mechanisms remain unclear. Here we characterized the bone phenotype of a novel Cthrc1 null mouse strain using bone histomorphometry, μCT analysis and functional readouts for bone strength. In male Cthrc1 null mice both trabecular bone as well as cortical bone formation was impaired, whereas in female Cthrc1 null mice only trabecular bone parameters were altered. Novel and highly specific monoclonal antibodies revealed that CTHRC1 is expressed by osteocytes and osteoblasts, but not osteoclasts. Furthermore, Cthrc1 null mice exhibited increased bone resorption with increased number of osteoclast and increased osteoclast activity together with enhanced expression of osteoclastogenic genes such as c-Fos, Rankl, Trap, and Nfatc1. Differentiation of bone marrow-derived monocytes isolated from Cthrc1 null mice differentiated into osteoclasts as effectively as those from wildtype mice. In the presence of CTHRC1 osteoclastogenic differentiation of bone marrow-derived monocytes was dramatically inhibited as was functional bone resorption by osteoclasts. This process was accompanied by downregulation of osteoclastogenic marker genes, indicating that extrinsically derived CTHRC1 is required for such activity. In vitro, CTHRC1 had no effect on osteogenic differentiation of bone marrow stromal cells, however, calvarial osteoblasts from Cthrc1 null mice exhibited reduced osteogenic differentiation compared to osteoblasts from wildtypes. In a collagen antibody-induced arthritis model Cthrc1 null mice suffered significantly more severe inflammation and joint destruction than wildtypes, suggesting that CTHRC1 expressed by the activated synoviocytes has anti-inflammatory effects. Mechanistically, we found that CTHRC1 inhibited NFκB activation by preventing IκBα degradation while also inhibiting ERK1/2 activation. Collectively our studies demonstrate that CTHRC1 secreted from osteocytes and osteoblasts functions as an inhibitor of osteoclast differentiation via inhibition of NFκB-dependent signaling. Furthermore, our data suggest that CTHRC1 has potent anti-inflammatory properties that limit arthritic joint destruction.
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Affiliation(s)
- Yong-Ri Jin
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, United States
| | - J Patrizia Stohn
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, United States
| | - Qiaozeng Wang
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, United States
| | - Kenichi Nagano
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, United States
| | - Roland Baron
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, United States
| | - Mary L Bouxsein
- Beth Israel Deaconess Medical Center, Boston, MA, United States
| | - Clifford J Rosen
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, United States
| | | | - Volkhard Lindner
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, United States.
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21
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Abstract
Foxn1 (forkhead box N1), also known as the nude gene or winged-helix nude (Whn), is a forkhead transcription factor thought to be restricted to keratinocytes in the skin and thymus. Consistent with this tissue distribution, spontaneous or targeted mutation of Foxn1 results in the absence of both hair and a thymus. Genetic manipulation of the Foxn1 locus thus represents a powerful tool for tissue specific gene control in the skin and thymus, and tools such as Cre recombinase under control of the Foxn1 locus are widely used for this purpose. Unexpectedly, we show that Foxn1[Cre] exhibits unexpected activity in male germ cells, resulting in ubiquitous targeting of loxP-flanked alleles in all tissues in offspring from Foxn1[Cre] expressing male mice. Inheritance of recombined loxP alleles occurs independently of Cre inheritance (i.e., offspring lacking Cre nonetheless exhibit recombined alleles), suggesting that Foxn1[Cre] induced recombination in male germ cells must occur prior to meiosis in diploid germ cells. Together with previously published data, our results show that Foxn1, and alleles under its control, are expressed in the pre-meiotic male germline, revealing a new tool for germline targeting of genes, and raising important concerns for gender selection when using Foxn1 regulatory elements.
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22
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Zhu M, Sun BH, Saar K, Simpson C, Troiano N, Dallas SL, Tiede-Lewis LM, Nevius E, Pereira JP, Weinstein RS, Tommasini SM, Insogna KL. Deletion of Rac in Mature Osteoclasts Causes Osteopetrosis, an Age-Dependent Change in Osteoclast Number, and a Reduced Number of Osteoblasts In Vivo. J Bone Miner Res 2016; 31:864-73. [PMID: 26496249 PMCID: PMC4826801 DOI: 10.1002/jbmr.2733] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 10/16/2015] [Accepted: 10/20/2015] [Indexed: 12/30/2022]
Abstract
Rac1 and Rac2 are thought to have important roles in osteoclasts. Therefore, mice with deletion of both Rac1 and Rac2 in mature osteoclasts (DKO) were generated by crossing Rac1(flox/flox) mice with mice expressing Cre in the cathepsin K locus and then mating these animals with Rac2(-/-) mice. DKO mice had markedly impaired tooth eruption. Bone mineral density (BMD) was increased 21% to 33% in 4- to 6-week-old DKO mice at all sites when measured by dual-energy X-ray absorptiometry (DXA) and serum cross-linked C-telopeptide (CTx) was reduced by 52%. The amount of metaphyseal trabecular bone was markedly increased in DKO mice, but the cortices were very thin. Spinal trabecular bone mass was increased. Histomorphometry revealed significant reductions in both osteoclast and osteoblast number and function in 4- to 6-week-old DKO animals. In 14- to 16-week-old animals, osteoclast number was increased, although bone density was further increased. DKO osteoclasts had severely impaired actin ring formation, an impaired ability to generate acid, and reduced resorptive activity in vitro. In addition, their life span ex vivo was reduced. DKO osteoblasts expressed normal differentiation markers except for the expression of osterix, which was reduced. The DKO osteoblasts mineralized normally in vitro, indicating that the in vivo defect in osteoblast function was not cell autonomous. Confocal imaging demonstrated focal disruption of the osteocytic dendritic network in DKO cortical bone. Despite these changes, DKO animals had a normal response to treatment with once-daily parathyroid hormone (PTH). We conclude that Rac1 and Rac2 have critical roles in skeletal metabolism.
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Affiliation(s)
- Meiling Zhu
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Ben-hua Sun
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Katarzyna Saar
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Christine Simpson
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Nancy Troiano
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine, New Haven, CT, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - LeAnn M Tiede-Lewis
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Erin Nevius
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - João P Pereira
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Robert S Weinstein
- Department of Internal Medicine, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Health Care System, Little Rock, AR, USA
| | - Steven M Tommasini
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine, New Haven, CT, USA
| | - Karl L Insogna
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
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Liu Z, Brown A, Fisher D, Wu Y, Warren J, Cui X. Tissue Specific Expression of Cre in Rat Tyrosine Hydroxylase and Dopamine Active Transporter-Positive Neurons. PLoS One 2016; 11:e0149379. [PMID: 26886559 PMCID: PMC4757100 DOI: 10.1371/journal.pone.0149379] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 02/01/2016] [Indexed: 12/20/2022] Open
Abstract
The rat is a preferred model system over the mouse for neurological studies, and cell type-specific Cre expression in the rat enables precise ablation of gene function in neurons of interest, which is especially valuable for neurodegenerative disease modeling and optogenetics. Yet, few such Cre rats are available. Here we report the characterization of two Cre rats, tyrosine hydroxylase (TH)-Cre and dopamine active transporter (DAT or Slc6a3)-Cre, by using a combination of immunohistochemistry (IHC) and mRNA fluorescence in situ hybridization (FISH) as well as a fluorescent reporter for Cre activity. We detected Cre expression in expected neurons in both Cre lines. Interestingly, we also found that in Th-Cre rats, but not DAT-Cre rats, Cre is expressed in female germ cells, allowing germline excision of the floxed allele and hence the generation of whole-body knockout rats. In summary, our data demonstrate that targeted integration of Cre cassette lead to faithful recapitulation of expression pattern of the endogenous promoter, and mRNA FISH, in addition to IHC, is an effective method for the analysis of the spatiotemporal gene expression patterns in the rat brain, alleviating the dependence on high quality antibodies that are often not available against rat proteins. The Th-Cre and the DAT-Cre rat lines express Cre in selective subsets of dopaminergic neurons and should be particularly useful for researches on Parkinson’s disease.
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Affiliation(s)
- Zhenyi Liu
- SAGE Labs, A Horizon Discovery Group Company, Saint Louis, MO, United States of America
| | - Andrew Brown
- SAGE Labs, A Horizon Discovery Group Company, Saint Louis, MO, United States of America
| | - Dan Fisher
- SAGE Labs, A Horizon Discovery Group Company, Saint Louis, MO, United States of America
| | - Yumei Wu
- SAGE Labs, A Horizon Discovery Group Company, Saint Louis, MO, United States of America
| | - Joe Warren
- SAGE Labs, A Horizon Discovery Group Company, Saint Louis, MO, United States of America
| | - Xiaoxia Cui
- SAGE Labs, A Horizon Discovery Group Company, Saint Louis, MO, United States of America
- * E-mail:
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24
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Ablation of Tak1 in osteoclast progenitor leads to defects in skeletal growth and bone remodeling in mice. Sci Rep 2014; 4:7158. [PMID: 25418008 PMCID: PMC4241509 DOI: 10.1038/srep07158] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 10/21/2014] [Indexed: 01/20/2023] Open
Abstract
Tak1 is a MAPKKK that can be activated by growth factors and cytokines such as RANKL and BMPs and its downstream pathways include NF-κB and JNK/p38 MAPKs. Tak1 is essential for mouse embryonic development and plays critical roles in tissue homeostasis. Previous studies have shown that Tak1 is a positive regulator of osteoclast maturation, yet its roles in bone growth and remodeling have not been assessed, as mature osteoclast-specific Tak1 deletion with Cstk-Cre resulted in runtedness and postnatal lethality. Here we generated osteoclast progenitor (monocyte)-specific Tak1 knockout mice and found that these mice show normal body weight, limb size and fertility, and osteopetrosis with severity similar to that of RANK or RANKL deficient mice. Mechanistically, Tak1 deficiency altered the signaling of NF-κB, p38MAPK, and Smad1/5/8 and the expression of PU.1, MITF, c-Fos, and NFATc1, suggesting that Tak1 regulates osteoclast differentiation at multiple stages via multiple signaling pathways. Moreover, the Tak1 mutant mice showed defects in skull, articular cartilage, and mesenchymal stromal cells. Ex vivo Tak1-/- monocytes also showed enhanced ability in promoting osteogenic differentiation of mesenchymal stromal cells. These findings indicate that Tak1 functions in osteoclastogenesis in a cell-autonomous manner and in osteoblastogenesis and chondrogenesis in non-cell-autonomous manners.
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25
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Miyazaki T, Iwasawa M, Nakashima T, Mori S, Shigemoto K, Nakamura H, Katagiri H, Takayanagi H, Tanaka S. Intracellular and extracellular ATP coordinately regulate the inverse correlation between osteoclast survival and bone resorption. J Biol Chem 2012; 287:37808-23. [PMID: 22988253 PMCID: PMC3488055 DOI: 10.1074/jbc.m112.385369] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 09/09/2012] [Indexed: 11/06/2022] Open
Abstract
Osteoclasts, highly differentiated bone-resorbing cells of hematopoietic origin, have two conflicting tendencies: a lower capacity to survive and a higher capacity to execute energy-consuming activities such as bone resorption. Here, we report that when compared with their precursors, mature mitochondria-rich osteoclasts have lower levels of intracellular ATP, which is associated with receptor activator of nuclear factor κ-B ligand (RANKL)-induced Bcl-x(L) down-regulation. Severe ATP depletion, caused by disrupting mitochondrial transcription factor A (Tfam) gene, leads to increased bone-resorbing activity despite accelerated apoptosis. Although AMP-activated protein kinase (AMPK) activation by ATP depletion is not involved in the regulation of osteoclast function, the release of ATP from intracellular stores negatively regulates bone-resorbing activity through an autocrine/paracrine feedback loop by altering cytoskeletal structures. Furthermore, osteoclasts derived from aged mice exhibit reduced mitochondrial DNA (mtDNA) and intracellular ATP levels with increased bone-resorbing activity, implicating the possible involvement of age-related mitochondrial dysfunction in osteoporosis. Thus, our study provides evidence for a mechanism underlying the control of cellular functions by reciprocal changes in intracellular and extracellular ATP, which regulate the negative correlation between osteoclast survival and bone resorption.
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Affiliation(s)
- Tsuyoshi Miyazaki
- Department of Geriatric Medicine, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
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