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Skelton AM, Cohen DJ, Boyan BD, Schwartz Z. Osteoblast-Derived Matrix Vesicles Exhibit Exosomal Traits and a Unique Subset of microRNA: Their Caveolae-Dependent Endocytosis Results in Reduced Osteogenic Differentiation. Int J Mol Sci 2023; 24:12770. [PMID: 37628952 PMCID: PMC10454939 DOI: 10.3390/ijms241612770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
Matrix vesicles (MVs) are nano-sized extracellular vesicles that are anchored in the extracellular matrix (ECM). In addition to playing a role in biomineralization, osteoblast-derived MVs were recently suggested to have regulatory duties. The aims of this study were to establish the characteristics of osteoblast-derived MVs in the context of extracellular vesicles like exosomes, assess their role in modulating osteoblast differentiation, and examine their mechanism of uptake. MVs were isolated from the ECM of MG63 human osteoblast-like cell cultures and characterized via enzyme activity, transmission electron microscopy, nanoparticle tracking analysis, Western blot, and small RNA sequencing. Osteoblasts were treated with MVs from two different culture conditions (growth media [GM]; osteogenic media [OM]) to evaluate their effects on the differentiation and production of inflammatory markers and on macrophage polarization. MV endocytosis was assessed using a lipophilic, fluorescent dye and confocal microscopy with the role of caveolae determined using methyl-β-cyclodextrin. MVs exhibited a four-fold enrichment in alkaline phosphatase specific activity compared to plasma membranes; were 50-150 nm in diameter; possessed exosomal markers CD63, CD81, and CD9 and endosomal markers ALIX, TSG101, and HSP70; and were selectively enriched in microRNA linked to an anti-osteogenic effect and to M2 macrophage polarization. Treatment with GM or OM MVs decreased osteoblast differentiation. Osteoblasts endocytosed MVs using a mechanism that involves caveolae. These results support the hypothesis that osteoblasts produce MVs that participate in the regulation of osteogenesis.
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Affiliation(s)
- Anne M. Skelton
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; (A.M.S.); (B.D.B.)
| | - D. Joshua Cohen
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA;
| | - Barbara D. Boyan
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; (A.M.S.); (B.D.B.)
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA;
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Zvi Schwartz
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA;
- Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Joshua Cohen D, ElBaradie K, Boyan BD, Schwartz Z. Sex-specific effects of 17β-estradiol and dihydrotestosterone (DHT) on growth plate chondrocytes are dependent on both ERα and ERβ and require palmitoylation to translocate the receptors to the plasma membrane. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159028. [PMID: 34416391 DOI: 10.1016/j.bbalip.2021.159028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/19/2021] [Accepted: 08/13/2021] [Indexed: 11/24/2022]
Abstract
Rat costochondral cartilage growth plate chondrocytes exhibit cell sex-specific responses to 17β-estradiol (E2), testosterone, and dihydrotestosterone (DHT). Mechanistically, E2 and DHT stimulate proliferation and extracellular matrix synthesis in chondrocytes from female and male rats, respectively, by signaling through protein kinase C (PKC) and phospholipase C (PLC). Estrogen receptors (ERα; ERβ) and androgen receptors (ARs) are present in both male and female cells, but it is not known whether they interact to elicit sex-specific signaling. We used specific agonists and antagonists of these receptors to examine the relative contributions of ERs and ARs in membrane-mediated E2 signaling in female chondrocytes and DHT signaling in male chondrocytes. PKC activity in female chondrocytes was stimulated by agonists of ERα and ERβ and required intact caveolae; PKC activity was inhibited by the E2 enantiomer and by an inhibitor of ERβ. Western blots of cell lysates co-immunoprecipitated for ERα suggested the formation of a complex containing both ERα and ERß with E2 treatment. DHT and DHT agonists activated PKC in male cells, while AR inhibition blocked the stimulatory effect of DHT on PKC. Inhibition of ERα and ERβ also blocked PKC activation by DHT. Western blots of whole-cell lysates, plasma membranes, and caveolae indicated the translocation of AR to the plasma membrane and specifically to caveolae with DHT treatment. These results suggest that E2 and DHT promote chondrocyte differentiation via the ability of ARs and ERs to form a complex. The results also indicate that intact caveolae and palmitoylation of the membrane receptor(s) or membrane receptor complex containing ERα and ERβ is required for E2 and DHT membrane-associated PKC activity in costochondral cartilage cells.
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Affiliation(s)
- D Joshua Cohen
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Khairat ElBaradie
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30033, USA
| | - Barbara D Boyan
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30033, USA.
| | - Zvi Schwartz
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA; Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Sarem M, Otto O, Tanaka S, Shastri VP. Cell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesis. Stem Cell Res Ther 2019; 10:10. [PMID: 30630531 PMCID: PMC6329065 DOI: 10.1186/s13287-018-1103-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 12/03/2018] [Accepted: 12/09/2018] [Indexed: 01/09/2023] Open
Abstract
Background Although mesenchymal stem/stromal cell (MSC) chondrogenic differentiation has been thoroughly investigated, the rudiments for enhancing chondrogenesis have remained largely dependent on external cues. Focus to date has been on extrinsic variables such as soluble signals, culture conditions (bioreactors), and mechanical stimulation. However, the role of intrinsic mechanisms of MSC programming-based mechanobiology remains to be explored. Since aggregation of MSCs, a prerequisite for chondrogenesis, generates tension within the cell agglomerate, we inquired if the initial number of cells forming the aggregate (aggregate cell number (ACN)) can impact chondrogenesis. Methods Aggregates of varying ACN were formed using well-established centrifugation approach. Progression of chondrogenic differentiation in the aggregates was assessed over 3 weeks in presence and absence of transforming growth factor-beta 1 (TGF-β1). Mechanical properties of the cells were characterized using high-throughput real-time deformability cytometry (RT-DC), and gene expression was analyzed using Affymetrix gene array. Expression of molecular markers linked to chondrogenesis was assessed using western blot and immunofluorescence. Results Reducing ACN from 500 k to 70 k lead to activation and acceleration of the chondrogenic differentiation, independent of soluble chondro-inductive factors, which involves changes to β-catenin-dependent TCF/LEF transcriptional activity and expression of anti-apoptotic protein survivin. RT-DC analysis revealed that stiffness and size of cells within aggregates are modulated by ACN. A direct correlation between progression of chondrogenesis and emergence of stiffer cell phenotype was found. Affymetrix gene array analysis revealed a downregulation of genes associated with lipid synthesis and regulation, which could account for observed changes in cell stiffness. Immunofluorescence and western blot analysis revealed that increasing ACN upregulates the expression of lipid raft protein caveolin-1, a β-catenin binding partner, and downregulates the expression of N-cadherin. As a demonstration of the relevance of these findings in MSC-based strategies for skeletal repair, it is shown that implanting aggregates within collagenous matrix not only decreases the necessity for high cell numbers but also leads to marked improvement in the quality of the deposited tissue. Conclusions This study presents a simple and donor-independent strategy to enhance the efficiency of MSC chondrogenic differentiation and identifies changes in cell mechanics coincident with MSC chondrogenesis with potential translational applications. Electronic supplementary material The online version of this article (10.1186/s13287-018-1103-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Melika Sarem
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier Str.31, 79104, Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, 79104, Freiburg, Germany.,Helmholtz Virtual Institute on Multifunctional Biomaterials for Medicine, Kantstr. 55, 14513, Teltow, Germany
| | - Oliver Otto
- Centre for Innovation Competence - Humoral Immune Response in Cardiovascular Diseases, University of Greifswald, Fleischmannstr. 42-44, 17489, Greifswald, Germany
| | - Simon Tanaka
- Computational Biology Group, D-BSSE, ETH Zürich, Mattenstrasse 26, 4058, Basel, Switzerland
| | - V Prasad Shastri
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier Str.31, 79104, Freiburg, Germany. .,BIOSS Centre for Biological Signaling Studies, University of Freiburg, 79104, Freiburg, Germany. .,Helmholtz Virtual Institute on Multifunctional Biomaterials for Medicine, Kantstr. 55, 14513, Teltow, Germany.
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Reichrath J, Saternus R, Vogt T. Endocrine actions of vitamin D in skin: Relevance for photocarcinogenesis of non-melanoma skin cancer, and beyond. Mol Cell Endocrinol 2017; 453:96-102. [PMID: 28526240 DOI: 10.1016/j.mce.2017.05.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 05/01/2017] [Accepted: 05/01/2017] [Indexed: 11/20/2022]
Abstract
The skin represents a pivotal organ for the human body's vitamin D endocrine system, being both the site of ultraviolet (UV)-B-induced vitamin D synthesis and a target tissue for the pluripotent effects of 1,25(OH)2D3 and other biologically active vitamin D metabolites. As many other steroid hormones, 1,25(OH)2D3 exerts its effects via two independent signal transduction pathways: the classical genomic and the non-genomic pathway. While non-genomic effects of 1,25(OH)2D3 are in part exerted via effects on intracellular calcium, genomic effects are mediated by the vitamin D receptor (VDR). Recent findings convincingly support the concept of a new function of the VDR as a tumor suppressor in skin, with key components of the vitamin D endocrine system, including VDR, CYP24A1, CYP27A1, and CYP27B1 being strongly expressed in non-melanoma skin cancer (NMSC). It has now been shown that anti-tumor effects of VDR, that include some of its ligand-induced growth-regulatory effects, are at least in part mediated by interacting in a highly coordinated manner with the p53 family (p53/p63/p73) in response to a large number of alterations in cell homeostasis, including UV-induced DNA damage, a hallmark for skin photocarcinogenesis. Considering the relevance of the vitamin D endocrine system for carcinogenesis of skin cancer, it is not surprising that low 25(OH)D serum concentrations and genetic variants (SNPs) of the vitamin D endocrine system have been identified as potential risk factors for occurrence and prognosis of skin malignancies. In conclusion, an increasing body of evidence now convincingly supports the concept that the vitamin D endocrine system is of relevance for photocarcinogenesis and progression of NMSC and that its pharmacologic modulation by vitamin D, 1,25(OH)2D3, and analogs represents a promising new strategy for prevention and/or treatment of these malignancies.
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Affiliation(s)
- Jörg Reichrath
- Center for Clinical and Experimental Photo-Dermatology and Department of Dermatology, The Saarland University Hospital, 66421 Homburg, Germany.
| | - Roman Saternus
- Center for Clinical and Experimental Photo-Dermatology and Department of Dermatology, The Saarland University Hospital, 66421 Homburg, Germany
| | - Thomas Vogt
- Center for Clinical and Experimental Photo-Dermatology and Department of Dermatology, The Saarland University Hospital, 66421 Homburg, Germany
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Hsu SL, Cheng JH, Wang CJ, Ko JY, Hsu CH. Extracorporeal Shockwave Therapy Enhances Expression of Pdia-3 Which Is a Key Factor of the 1α,25-Dihydroxyvitamin D 3 Rapid Membrane Signaling Pathway in Treatment of Early Osteoarthritis of the Knee. Int J Med Sci 2017; 14:1220-1230. [PMID: 29104478 PMCID: PMC5666555 DOI: 10.7150/ijms.20303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 07/05/2017] [Indexed: 11/17/2022] Open
Abstract
The goal of our research was demonstrated that multiple molecules in microenvironments of the early osteoarthritis (OA) joint tissue may be actively responded to extracorporeal shockwave therapy (ESWT) treatment, which potentially regulated biological function of chondrocytes and synovial cells in early OA knee. We demonstrated that shockwave treatment induced the expression of protein-disulfide isomerase-associated 3 (Pdia-3) which was a significant mediator of the 1α,25-Dihydroxyvitamin D 3 (1α,25(OH)2D3) rapid signaling pathway, using two-dimensional electrophoresis, histological analysis and quantitative polymerase chain reaction (qPCR). We observed that the expression of Pdia-3 at 2 weeks was significantly higher than that of other group at 4, 8, and 12 weeks post-shockwave treatment in early OA rat knee model. The other factors of the rapid membrane signaling pathway, including extracellular signal-regulated protein kinases 1 (ERK1), osteopontin (OPG), alkaline phosphatase (ALP), and matrix metallopeptidase 13 (MMP13) were examined and were found to be significantly increased at 2 weeks post-shockwave treatment by qPCR in early OA of the knee. Our proteomic data revealed significant Pdia-3 expression in microenvironments of OA joint tissue that could be actively responded to ESWT, which may potentially regulate the biological functions of chondrocytes and osteoblasts in the treatment of the early OA of the knee.
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Affiliation(s)
- Shan-Ling Hsu
- Center for Shockwave Medicine and Tissue Engineering.,Department of Orthopedic Surgery
| | - Jai-Hong Cheng
- Center for Shockwave Medicine and Tissue Engineering.,Medical Research, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Ching-Jen Wang
- Center for Shockwave Medicine and Tissue Engineering.,Department of Orthopedic Surgery
| | - Jih-Yang Ko
- Center for Shockwave Medicine and Tissue Engineering.,Department of Orthopedic Surgery
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Choudhary D, Pandey A, Adhikary S, Ahmad N, Bhatia C, Bhambhani S, Trivedi PK, Trivedi R. Genetically engineered flavonol enriched tomato fruit modulates chondrogenesis to increase bone length in growing animals. Sci Rep 2016; 6:21668. [PMID: 26917158 PMCID: PMC4768317 DOI: 10.1038/srep21668] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 01/26/2016] [Indexed: 11/19/2022] Open
Abstract
Externally visible body and longitudinal bone growth is a result of proliferation of chondrocytes. In growth disorder, there is delay in the age associated increase in height. The present study evaluates the effect of extract from transgenic tomato fruit expressing AtMYB12 transcription factor on bone health including longitudinal growth. Constitutive expression of AtMYB12 in tomato led to a significantly enhanced biosynthesis of flavonoids in general and the flavonol biosynthesis in particular. Pre-pubertal ovary intact BALB/c mice received daily oral administration of vehicle and ethanolic extract of wild type (WT-TOM) and transgenic AtMYB12-tomato (MYB12-TOM) fruits for six weeks. Animal fed with MYB12-TOM showed no inflammation in hepatic tissues and normal sinusoidal Kupffer cell morphology. MYB12-TOM extract significantly increased tibial and femoral growth and subsequently improved the bone length as compared to vehicle and WT-TOM. Histomorphometry exhibited significantly wider distal femoral and proximal tibial growth plate, increased number and size of hypertrophic chondrocytes in MYB12-TOM which corroborated with micro-CT and expression of BMP-2 and COL-10, marker genes for hypertrophic cells. We conclude that metabolic reprogramming of tomato by AtMYB12 has the potential to improve longitudinal bone growth thus helping in achievement of greater peak bone mass during adolescence.
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Affiliation(s)
- Dharmendra Choudhary
- CSIR-Central Drug Research Institute (CSIR-CDRI), Endocrinology Division, Jankipuram Extension, Sitapur Road, Lucknow-226031, INDIA
| | - Ashutosh Pandey
- CSIR-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow-226 001, INDIA
| | - Sulekha Adhikary
- CSIR-Central Drug Research Institute (CSIR-CDRI), Endocrinology Division, Jankipuram Extension, Sitapur Road, Lucknow-226031, INDIA
| | - Naseer Ahmad
- CSIR-Central Drug Research Institute (CSIR-CDRI), Endocrinology Division, Jankipuram Extension, Sitapur Road, Lucknow-226031, INDIA
| | - Chitra Bhatia
- CSIR-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow-226 001, INDIA
| | - Sweta Bhambhani
- CSIR-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow-226 001, INDIA
| | - Prabodh Kumar Trivedi
- CSIR-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow-226 001, INDIA
| | - Ritu Trivedi
- CSIR-Central Drug Research Institute (CSIR-CDRI), Endocrinology Division, Jankipuram Extension, Sitapur Road, Lucknow-226031, INDIA
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7
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Doroudi M, Olivares-Navarrete R, Boyan BD, Schwartz Z. A review of 1α,25(OH)2D3 dependent Pdia3 receptor complex components in Wnt5a non-canonical pathway signaling. J Steroid Biochem Mol Biol 2015; 152:84-8. [PMID: 25845934 DOI: 10.1016/j.jsbmb.2015.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 03/16/2015] [Accepted: 04/02/2015] [Indexed: 11/17/2022]
Abstract
Wnt5a and 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] regulate endochondral ossification. 1α,25(OH)2D3 initiates its calcium-dependent effects via its membrane-associated receptor, protein disulfide isomerase A3 (Pdia3). 1α,25(OH)2D3 binding to Pdia3 triggers the interaction between Pdia3 and phospholipase A2 (PLA2)-activating protein (PLAA), resulting in downstream activation of calcium/calmodulin-dependent protein kinase II (CaMKII), PLA2, and protein kinase C (PKC). Wnt5a initiates its calcium-dependent effects via binding its receptors Frizzled2 (FZD2) and Frizzled5 (FZD5) and receptor tyrosine kinase-like orphan receptor 2 (ROR2), activating intracellular calcium release and stimulating PKC and CaMKII. Recent efforts to determine the inter-relation between Wnt5a and 1α,25(OH)2D3 signaling pathways have demonstrated that Wnt5a signals through a CaMKII/PLA2/PGE2/PKC cascade in chondrocytes and osteoblasts in which the components of the Pdia3 receptor complex were required. Furthermore, ROR2, but not FZD2 or FZD5, was required to mediate the calcium-dependent actions of 1α,25(OH)2D3. This review provides evidence that 1α,25(OH)2D3 and Wnt5a mediate their calcium-dependent pathways via similar receptor components and proposes that these pathways may interact since they are competing for the same receptor complex components.
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Affiliation(s)
- Maryam Doroudi
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Rene Olivares-Navarrete
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Barbara D Boyan
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA; Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Zvi Schwartz
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA; Department of Periodontics, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78284, USA
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Doroudi M, Schwartz Z, Boyan BD. Membrane-mediated actions of 1,25-dihydroxy vitamin D3: a review of the roles of phospholipase A2 activating protein and Ca(2+)/calmodulin-dependent protein kinase II. J Steroid Biochem Mol Biol 2015; 147:81-4. [PMID: 25448737 PMCID: PMC4323845 DOI: 10.1016/j.jsbmb.2014.11.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/13/2014] [Accepted: 11/02/2014] [Indexed: 12/11/2022]
Abstract
The secosteroid 1α,25-dihydroxy vitamin D3 [1α,25(OH)2D3] acts on cells via classical steroid hormone receptor-mediated gene transcription and by initiating rapid membrane-mediated signaling pathways. In its membrane-initiated pathway, after 1α,25(OH)2D3 interacts with protein disulfide isomerase, family A, member 3 (Pdia3) in caveolae, phospholipase A2 (PLA2) and protein kinase C (PKC) are activated. Recent efforts to determine the signaling proteins involved in the 1α,25(OH)2D3 signal from Pdia3 to PLA2 have indicated that phospholipase A2 activating protein (PLAA) and Ca(2+)/calmodulin-dependent kinase II (CaMKII) are required. PLAA is located in caveolae, where it interacts with Pdia3 and caveolin-1 (Cav-1) to initiate rapid signaling via CaMKII, activating PLA2, leading to activation of protein kinase C (PKC) and PKC-dependent responses.
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Affiliation(s)
- Maryam Doroudi
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, U.S.A
| | - Zvi Schwartz
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, U.S.A
- Department of Periodontics, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78284, U.S.A
| | - Barbara D. Boyan
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, U.S.A
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, U.S.A
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, U.S.A
- Address for Correspondence: Barbara D. Boyan, Ph.D., School of Engineering, Virginia Commonwealth University, 601 West Main Street, Richmond, VA 23284-3068, Phone: 804-828-0190, FAX: 804-828-9866,
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Doroudi M, Plaisance MC, Boyan BD, Schwartz Z. Membrane actions of 1α,25(OH)2D3 are mediated by Ca(2+)/calmodulin-dependent protein kinase II in bone and cartilage cells. J Steroid Biochem Mol Biol 2015; 145:65-74. [PMID: 25263660 DOI: 10.1016/j.jsbmb.2014.09.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 09/12/2014] [Accepted: 09/16/2014] [Indexed: 01/05/2023]
Abstract
1α,25(OH)2D3 regulates osteoblasts and chondrocytes via its membrane-associated receptor, protein disulfide isomerase A3 (Pdia3) in caveolae. 1α,25(OH)2D3 binding to Pdia3 leads to phospholipase-A2 (PLA2)-activating protein (PLAA) activation, stimulating cytosolic PLA2 and resulting in prostaglandin E2 (PGE2) release and PKCα activation, subsequently stimulating differentiation. However, how PLAA transmits the signal to cPLA2 is unknown. Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII) activation is required for PLA2 activation in vascular smooth muscle cells, suggesting a similar role in 1α,25(OH)2D3-dependent signaling. The aim of the present study is to evaluate the roles of CaM and CaMKII as mediators of 1α,25(OH)2D3-stimulated PLAA-dependent activation of cPLA2 and PKCα, and downstream biological effects. The results indicated that 1α,25(OH)2D3 and PLAA-peptide increased CaMKII activity within 9 min. Silencing Cav-1, Pdia3 or Plaa in osteoblasts suppressed this effect. Similarly, antibodies against Plaa or Pdia3 blocked 1α,25(OH)2D3-dependent CaMKII. Caveolae disruption abolished activation of CaMKII by 1α,25(OH)2D3 or PLAA. CaMKII-specific and CaM-specific inhibitors reduced cPLA2 and PKC activities, PGE2 release and osteoblast maturation markers in response to 1α,25(OH)2D3. Camk2a-silenced but not Camk2b-silenced osteoblasts showed comparable effects. Immunoprecipitation showed increased interaction of CaM and PLAA in response to 1α,25(OH)2D3. The results indicate that membrane actions of 1α,25(OH)2D3 via Pdia3 triggered the interaction between PLAA and CaM, leading to dissociation of CaM from caveolae, activation of CaMKII, and downstream PLA2 activation, and suggest that CaMKII plays a major role in membrane-mediated actions of 1α,25(OH)2D3.
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Affiliation(s)
- Maryam Doroudi
- School of Biology, Georgia Institute of Technology, 310 Ferst Drive NW, Atlanta, GA 30332, USA
| | - Marc C Plaisance
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Drive NW, Atlanta, GA 30332, USA
| | - Barbara D Boyan
- School of Biology, Georgia Institute of Technology, 310 Ferst Drive NW, Atlanta, GA 30332, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Drive NW, Atlanta, GA 30332, USA; Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, 601 West Main Street, Richmond, VA 23284, USA.
| | - Zvi Schwartz
- Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, 601 West Main Street, Richmond, VA 23284, USA
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Abstract
1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] is crucial for normal skeletal development and bone homeostasis. Protein disulfide isomerase family A, member 3 (PDIA3) mediates 1α,25(OH)2D3 initiated-rapid membrane signaling in several cell types. To understand its role in regulating skeletal development, we generated Pdia3-deficient mice and examined the physiologic consequence of Pdia3-disruption in embryos and Pdia3+/− heterozygotes at different ages. No mice homozygous for the Pdia3-deletion were found at birth nor were there embryos after E12.5, indicating that targeted disruption of the Pdia3 gene resulted in early embryonic lethality. Pdia3-deficiency also resulted in skeletal manifestations as revealed by µCT analysis of the tibias. In comparison to wild type mice, Pdia3 heterozygous mice displayed expanded growth plates associated with decreased tether formation. Histomorphometry also showed that the hypertrophic zone in Pdia3+/− mice was more cellular than seen in wild type growth plates. Metaphyseal trabecular bone in Pdia3+/− mice exhibited an age-dependent phenotype with lower BV/TV and trabecular numbers, which was most pronounced at 15 weeks of age. Bone marrow cells from Pdia3+/− mice exhibited impaired osteoblastic differentiation, based on reduced expression of osteoblast markers and mineral deposition compared to cells from wild type animals. Collectively, our findings provide in vivo evidence that PDIA3 is essential for normal skeletal development. The fact that the Pdia3+/− heterozygous mice share a similar growth plate and bone phenotype to nVdr knockout mice, suggests that PDIA3-mediated rapid membrane signaling might be an alternative mechanism responsible for 1α,25(OH)2D3’s actions in regulating skeletal development.
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11
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Doroudi M, Boyan BD, Schwartz Z. Rapid 1α,25(OH)₂D ₃ membrane-mediated activation of Ca²⁺/calmodulin-dependent protein kinase II in growth plate chondrocytes requires Pdia3, PLAA and caveolae. Connect Tissue Res 2014; 55 Suppl 1:125-8. [PMID: 25158196 DOI: 10.3109/03008207.2014.923882] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
1α,25-Dihydroxy vitamin D3 [1α,25(OH)2D3] regulates growth zone chondrocytes (GC) via classical steroid hormone receptor-mediated gene transcription and by initiating rapid membrane-mediated signaling pathways. 1α,25(OH)2D3 initiates its membrane effects via its specific membrane-associated receptor (Pdia3) in caveolae. 1α,25(OH)2D3 binding to Pdia3 leads to phospholipase-A2 (PLA2)-activating protein (PLAA) activation, stimulating PLA2, resulting in prostaglandin E2 (PGE2) release and protein kinase C activation. Recently, we reported that 1α,25(OH)2D3 rapidly activates Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in GC cells. However, the roles of Pdia3, PLAA and caveolae in 1α,25(OH)2D3-dependent rapid activation of CaMKII are not clear. The aim of the present study was to evaluate the roles of Pdia3, PLAA and caveolae in 1α,25(OH)2D3 membrane-stimulated CaMKII activation. Pre-treating chondrocytes from the growth zone of the rat costochondral cartilage with antibodies against PLAA or Pdia3 blocked activation of CaMKII by 1α,25(OH)2D3. PLAA peptide rapidly activated CaMKII in GC cells. Caveolae disruption abolished CaMKII activation in response to 1α,25(OH)2D3 or PLAA peptide treatment. Immunoprecipitation studies showed increased CaM binding to PLAA in response to 1α,25(OH)2D3. The results indicated that Pdia3, PLAA and caveolae are required for rapid 1α,25(OH)2D3 membrane-mediated activation of CaMKII. 1α,25(OH)2D3 signaling via Pdia3 receptor triggered the interaction between PLAA and CaM suggesting that CaM may play a major role linking PLAA to CaMKII in membrane-mediated actions of 1α,25(OH)2D3.
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Affiliation(s)
- Maryam Doroudi
- School of Biology, Georgia Institute of Technology , Atlanta, GA , USA and
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Doroudi M, Olivares-Navarrete R, Hyzy SL, Boyan BD, Schwartz Z. Signaling components of the 1α,25(OH)2D3-dependent Pdia3 receptor complex are required for Wnt5a calcium-dependent signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2365-75. [PMID: 24946135 DOI: 10.1016/j.bbamcr.2014.06.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 06/06/2014] [Accepted: 06/09/2014] [Indexed: 11/25/2022]
Abstract
Wnt5a and 1α,25(OH)2D3 are important regulators of endochondral ossification. In osteoblasts and growth plate chondrocytes, 1α,25(OH)2D3 initiates rapid effects via its membrane-associated receptor protein disulfide isomerase A3 (Pdia3) in caveolae, activating phospholipase A2 (PLA2)-activating protein (PLAA), calcium/calmodulin-dependent protein kinase II (CaMKII), and PLA2, resulting in protein kinase C (PKC) activation. Wnt5a initiates its calcium-dependent effects via intracellular calcium release, activating PKC and CaMKII. We investigated the requirement for components of the Pdia3 receptor complex in Wnt5a calcium-dependent signaling. We determined that Wnt5a signals through a CaMKII/PLA2/PGE2/PKC cascade. Silencing or blocking Pdia3, PLAA, or vitamin D receptor (VDR), and inhibition of calmodulin (CaM), CaMKII, or PLA2 inhibited Wnt5a-induced PKC activity. Wnt5a activated PKC in caveolin-1-silenced cells, but methyl-beta-cyclodextrin reduced its stimulatory effect. 1α,25(OH)2D3 reduced stimulatory effects of Wnt5a on PKC in a dose-dependent manner. In contrast, Wnt5a had a biphasic effect on 1α,25(OH)2D3-stimulated PKC activation; 50ng/ml Wnt5a caused a 2-fold increase in 1α,25(OH)2D3-stimulated PKC but higher Wnt5a concentrations reduced 1α,25(OH)2D3-stimulated PKC activation. Western blots showed that Wnt receptors Frizzled2 (FZD2) and Frizzled5 (FZD5), and receptor tyrosine kinase-like orphan receptor 2 (ROR2) were localized to caveolae. Blocking ROR2, but not FZD2 or FZD5, abolished the stimulatory effects of 1α,25(OH)2D3 on PKC and CaMKII. 1α,25(OH)2D3 membrane receptor complex components (Pdia3, PLAA, caveolin-1, CaM) interacted with Wnt5a receptors/co-receptors (ROR2, FZD2, FZD5) in immunoprecipitation studies, interactions that changed with either 1α,25(OH)2D3 or Wnt5a treatment. This study demonstrates that 1α,25(OH)2D3 and Wnt5a mediate their effects via similar receptor components and suggests that these pathways may interact.
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Affiliation(s)
- Maryam Doroudi
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Rene Olivares-Navarrete
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Sharon L Hyzy
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Barbara D Boyan
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA; Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, USA.
| | - Zvi Schwartz
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA; Department of Periodontics, The University of Texas Health Science Center at San Antonio, San Antonio, TX, 78284, USA
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Abstract
Traditionally, steroid hormones such as the vitamin D3 metabolites, testosterone and dihydrotesterone, and 17β-estradiol act through cytosolic and nuclear receptors that directly interact with DNA to alter gene transcription and regulate cellular development. However, recent studies focused on rapid and membrane effects of steroid hormones have given invaluable insight into their non-classical mechanisms of action. In some cases, the traditional receptors were implicated as acting also in the plasma membrane as membrane-associated receptors. However, recent data have demonstrated the presence of an alternative splicing variant to traditional estrogen receptor α known as ERα36, which is present in the plasma membranes of several different cell types including several cancer cell types and even in some normal cells including cartilage and bone cells. The physiological effects that result from the membrane activation of ERα36 may vary from one cell type to another, but the mechanism of action appears to use similar pathways such as the activation of various protein kinases and phospholipases leading to the activation of signaling cascades that result in rapid, non-genomic responses. These rapid responses can affect cell proliferation and apoptotic signaling, indirectly activate downstream genomic signaling through phosphorylation cascades of transcription factors, and crosstalk with classical pathways via interaction with classical receptors. This review describes the data from the last several years and discusses the non-classical, rapid, and membrane-associated cellular responses to steroid hormones, particularly 17β-estradiol, through the classical receptors ERα and ERβ and various non-classical receptors, especially estrogen receptor-α36 (ERα36).
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Affiliation(s)
- Reyhaan A Chaudhri
- School of Biology, Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA 30332, USA; Atlanta Clinical and Translational Science Institute, Emory University, 1440 Clifton Rd NE, Atlanta, GA 30322, USA
| | - Nofrat Schwartz
- Department of Otolaryngology, Meir Hospital, Tchernichovsky 59, Kfar Saba 44299, Israel
| | - Khairat Elbaradie
- School of Biology, Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA 30332, USA; Department of Zoology, Tanta University, 69 Tout Ankh Amoon St, Tanta 31111, Egypt
| | - Zvi Schwartz
- School of Engineering, Virginia Commonwealth University, 601 West Main Street, Suite 331, Richmond, VA 23284, USA; Department of Periodontics, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MSC 7894, San Antonio, TX 78229, USA
| | - Barbara D Boyan
- School of Biology, Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA 30332, USA; School of Engineering, Virginia Commonwealth University, 601 West Main Street, Suite 331, Richmond, VA 23284, USA.
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Doroudi M, Chen J, Boyan BD, Schwartz Z. New insights on membrane mediated effects of 1α,25-dihydroxy vitamin D3 signaling in the musculoskeletal system. Steroids 2014; 81:81-7. [PMID: 24291576 DOI: 10.1016/j.steroids.2013.10.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1α,25-Dihydroxy vitamin D3 [1α,25(OH)2D3] acts on cells via classical steroid hormone receptor-mediated gene transcription and by initiating rapid membrane-mediated signaling pathways. Two receptors have been implicated to play roles in 1α,25(OH)2D3 mediated rapid signaling, the classical nuclear vitamin D receptor (VDR) and protein disulfide isomerase, family A, member 3 (Pdia3). Long term efforts to investigate the roles of these two receptors demonstrated thatPdia3 is located in caveolae, where it interacts with phospholipase A2 (PLA2) activating protein (PLAA) and caveolin-1 (Cav-1) to initiate rapid signaling via Ca(++)/calmodulin-dependent protein kinase II (CaMKII), PLA2, phospholipase C (PLC), protein kinase C (PKC), and ultimately the ERK1/2 family of mitogen activated protein kinases (MAPK). VDR is present on the plasma membrane, and it is required for 1α,25(OH)2D3 induced rapid activation of Src. PDIA3+/- mice demonstrate an impaired musculoskeletal phenotype. Moreover, our studies examining mineralization of pre-osteoblasts in 3D culture have shown the physiological importance of Pdia3 and VDR interaction: knockdown of Pdia3 or VDR is characterized by impaired mineralization of the constructs.
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Affiliation(s)
- Maryam Doroudi
- School of Biology, Georgia Institute of Technology, 310 Ferst Dr. NW, Atlanta, GA, USA
| | - Jiaxuan Chen
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA; Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Barbara D Boyan
- School of Biology, Georgia Institute of Technology, 310 Ferst Dr. NW, Atlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA; School of Engineering, Virginia Commonwealth University, 601 West Main Street, Richmond, VA, USA
| | - Zvi Schwartz
- School of Engineering, Virginia Commonwealth University, 601 West Main Street, Richmond, VA, USA; Department of Periodontics, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
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15
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Plasma membrane Pdia3 and VDR interact to elicit rapid responses to 1α,25(OH)2D3. Cell Signal 2013; 25:2362-73. [DOI: 10.1016/j.cellsig.2013.07.020] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 07/19/2013] [Indexed: 12/29/2022]
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16
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Chen J, Lobachev KS, Grindel BJ, Farach-Carson MC, Hyzy SL, El-Baradie KB, Olivares-Navarrete R, Doroudi M, Boyan BD, Schwartz Z. Chaperone properties of pdia3 participate in rapid membrane actions of 1α,25-dihydroxyvitamin d3. Mol Endocrinol 2013; 27:1065-77. [PMID: 23660595 DOI: 10.1210/me.2012-1277] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Protein disulfide isomerase family A, member 3 (Pdia3) mediates many of the plasma membrane (PM)-associated rapid responses to 1α,25-dihydroxyvitamin D3 (1α,25[OH]2D3). It is not well understood how Pdia3, which is an endoplasmic reticulum (ER) chaperone, functions as a PM receptor for 1α,25(OH)2D3. We mutated 3 amino acids (K214 and R282 in the calreticulin interaction site and C406 in the isomerase catalytic site), which are important for Pdia3's ER chaperone function, and examined their role in responses to 1α,25(OH)2D3. Pdia3 constructs with and without the ER retention signal KDEL were used to investigate the PM requirement for Pdia3. Finally, we determined whether palmitoylation and/or myristoylation were required for Pdia3-mediated responses to 1α,25(OH)2D3. Overexpressing the Pdia3 R282A mutant in MC3T3-E1 cells increased PM phospholipase A2-activating protein, Rous sarcoma oncogene (c-Src), and caveolin-1 but blocked increases in 1α,25(OH)2D3-stimulated protein kinase C (PKC) seen in cells overexpressing wild-type Pdia3 (Pdia3Ovr cells). Cells overexpressing Pdia3 with K214A and C406S mutations had PKC activity comparable to untreated controls, indicating that the native response to 1α,25(OH)2D3 also was blocked. Overexpressing Pdia3[-KDEL] increased PM localization and augmented baseline PKC, but the stimulatory effect of 1α,25(OH)2D3 was comparable to that seen in wild-type cultures. In contrast, 1α,25(OH)2D3 increased prostaglandin E2 in Pdia3[±KDEL] cells. Although neither palmitoylation nor myristoylation was required for PM association of Pdia3, myristoylation was needed for PKC activation. These data indicate that both the chaperone functional domains and the subcellular location of Pdia3 control rapid membrane responses to 1α,25(OH)2D3.
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Affiliation(s)
- Jiaxuan Chen
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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17
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Elbaradie KB, Wang Y, Boyan BD, Schwartz Z. Sex-specific response of rat costochondral cartilage growth plate chondrocytes to 17β-estradiol involves differential regulation of plasma membrane associated estrogen receptors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1165-72. [DOI: 10.1016/j.bbamcr.2012.12.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 12/29/2012] [Accepted: 12/30/2012] [Indexed: 12/17/2022]
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18
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Doroudi M, Schwartz Z, Boyan BD. Phospholipase A2 activating protein is required for 1α,25-dihydroxyvitamin D3 dependent rapid activation of protein kinase C via Pdia3. J Steroid Biochem Mol Biol 2012; 132:48-56. [PMID: 22484374 DOI: 10.1016/j.jsbmb.2012.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 02/12/2012] [Accepted: 03/06/2012] [Indexed: 11/25/2022]
Abstract
1α,25-Dihydroxyvitamin D(3) (1,25D3) regulates musculoskeletal cells via two different mechanisms: vitamin D receptor (VDR)-dependent gene transcription and rapid membrane-signaling via VDR as well as protein disulfide isomerase, family A, member 3 (Pdia3). In chondrocytes from the costochondral cartilage growth zone (GC), ligand binding to Pdia3 causes a rapid increase in phospholipase A(2) (PLA(2)) activity leading to release of arachidonic acid and formation of lysophospholipid (LPL). LPL activates phospholipase C (PLC), and resulting inositol trisphosphate (IP(3)) and diacylglycerol contribute to PKCα activation and downstream activation of ERK1/2. PLA(2) activating protein (PLAA) is increased in the growth zone of rat growth plates suggesting that it mediates the 1,25D3-dependent pathway. This study examined the role of PLAA in mediating 1,25D3-dependent PKC activation using GC cells and MC3T3-E1 wild-type and PLAA-silenced osteoblasts as models. PLAA, Pdia3, and caveolin-1 (Cav-1) were detected in plasma membranes and caveolae of GC and MC3T3-E1 cells. Pdia3-immunoprecipitated samples were positive for PLAA only after 1,25D3 treatment. Cav-1 was detected when immunoprecipitated with anti-Pdia3 and anti-PLAA in both vehicle and 1,25D3 treated cells. These observations were confirmed by immunohistochemistry. 1,25D3 failed to activate PLA(2) and PKC or cause PGE(2) release in PLAA-silenced cells. PLAA-antibody successfully blocked the PLAA protein and consequently suppressed PKC activity in GC and MC3T3-E1 cells. Crosslinking studies confirmed the localization of PLAA on the extracellular face on the plasma membrane in untreated MC3T3-E1 cells. Taken together, our results suggest that PLAA is an important mediator of 1α,25(OH)(2)D(3) rapid membrane mediated signaling. 1α,25(OH)(2)D(3) likely causes conformational changes bringing Pdia3 into proximity with PLAA, and aiding in transducing the signal from caveolae to the plasma membrane.
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Affiliation(s)
- Maryam Doroudi
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
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19
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Boyan BD, Chen J, Schwartz Z. Mechanism of Pdia3-dependent 1α,25-dihydroxy vitamin D3 signaling in musculoskeletal cells. Steroids 2012; 77:892-6. [PMID: 22569272 DOI: 10.1016/j.steroids.2012.04.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 04/14/2012] [Accepted: 04/25/2012] [Indexed: 12/29/2022]
Abstract
1α,25-Dihydroxy vitamin D3 [1,25(OH)2D3] acts on cells through traditional steroid hormone receptor-mediated gene transcription and by initiating rapid membrane-associated signaling pathways. Two receptors have been implicated in rapid signaling by 1,25(OH)2D3, the classical nuclear vitamin D receptor (VDR) and the more recently identified protein disulfide isomerase, family A, member 3 (Pdia3). Our lab along with other groups has established various tools to investigate the role of these two receptors, including gene knock-out, conditional knock-out, silencing, and over-expression in various model systems (growth plate chondrocytes, osteoblastic cells, chick intestinal epithelial cells, mouse embryoid bodies, extracellular matrix vesicles and isolated cell membranes). The data demonstrate the requirement for Pdia3 in 1,25(OH)2D3 induced phospholipase A2 (PLA2) and protein kinase C (PKC) activation and downstream responses. Pdia3+/- heterozygote mice also exhibit both cartilage and bone defects. VDR is present on the plasma membrane and one VDR-/- mouse strain lacks transcaltachia, although 1,25(OH)2D3 induced PKC activation and transcaltachia are not affected in another VDR-/- mouse strain. In the context of osteoblast differentiation, both receptors are expressed during osteogenic commitment of embryoid bodies and silencing of each causes a more mature osteoblast phenotype in MC3T3-E1 pre-osteoblasts. Pdia3 exists in caveolae, where it interacts with PLA2 activating protein (PLAA) and caveolin-1 to initiate rapid signaling via PLA2, phospholipase C (PLC), PKC, and ultimately the ERK1/2 family of mitogen activated protein kinases (MAPK). Using the growth plate chondrocyte and matrix vesicle models, we have demonstrated that Pdia3-dependent signaling in response to 1,25(OH)2D3 regulates growth plate physiology.
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Affiliation(s)
- Barbara D Boyan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
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20
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Regulatory mechanism of transforming growth factor beta receptor type II degradation by interleukin-1 in primary chondrocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:983-6. [PMID: 22425785 DOI: 10.1016/j.bbamcr.2012.02.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 02/27/2012] [Accepted: 02/28/2012] [Indexed: 11/22/2022]
Abstract
Interleukin-1β (IL-1β), a key-cytokine in osteoarthritis, impairs TGFβ signaling through TβRII down-regulation by increasing its degradation. Here, we investigated the molecular mechanism that controls TßRII fate in IL-1ß treated cells. Chondrocytes were treated with IL-1ß in the presence of different inhibitors. TßRII and Cav-1 expression were assayed by Western blot and RT-PCR. We showed that IL-1ß-induced degradation of TßRII is dependent on proteasome and on its internalization in caveolae. In addition, IL-1ß enhances Cav-1 expression, a major constituent of lipid raft. In conclusion, we enlighten a new mechanism by which IL-1ß antagonizes TGFß pathway and propose a model of TßRII turnover regulation upon IL-1ß treatment.
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21
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Sequeira VB, Rybchyn MS, Tongkao-On W, Gordon-Thomson C, Malloy PJ, Nemere I, Norman AW, Reeve VE, Halliday GM, Feldman D, Mason RS. The role of the vitamin D receptor and ERp57 in photoprotection by 1α,25-dihydroxyvitamin D3. Mol Endocrinol 2012; 26:574-82. [PMID: 22322599 DOI: 10.1210/me.2011-1161] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
UV radiation (UVR) is essential for formation of vitamin D(3), which can be hydroxylated locally in the skin to 1α,25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)]. Recent studies implicate 1,25-(OH)(2)D(3) in reduction of UVR-induced DNA damage, particularly thymine dimers. There is evidence that photoprotection occurs through the steroid nongenomic pathway for 1,25-(OH)(2)D(3) action. In the current study, we tested the involvement of the classical vitamin D receptor (VDR) and the endoplasmic reticulum stress protein 57 (ERp57), in the mechanisms of photoprotection. The protective effects of 1,25-(OH)(2)D(3) against thymine dimers were abolished in fibroblasts from patients with hereditary vitamin D-resistant rickets that expressed no VDR protein, indicating that the VDR is essential for photoprotection. Photoprotection remained in hereditary vitamin D-resistant rickets fibroblasts expressing a VDR with a defective DNA-binding domain or a mutation in helix H1 of the classical ligand-binding domain, both defects resulting in a failure to mediate genomic responses, implicating nongenomic responses for photoprotection. Ab099, a neutralizing antibody to ERp57, and ERp57 small interfering RNA completely blocked protection against thymine dimers in normal fibroblasts. Co-IP studies showed that the VDR and ERp57 interact in nonnuclear extracts of fibroblasts. 1,25-(OH)(2)D(3) up-regulated expression of the tumor suppressor p53 in normal fibroblasts. This up-regulation of p53, however, was observed in all mutant fibroblasts, including those with no VDR, and with Ab099; therefore, VDR and ERp57 are not essential for p53 regulation. The data implicate the VDR and ERp57 as critical components for actions of 1,25-(OH)(2)D(3) against DNA damage, but the VDR does not require normal DNA binding or classical ligand binding to mediate photoprotection.
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Affiliation(s)
- Vanessa B Sequeira
- Department of Physiology, School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia 2006
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22
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St-Arnaud R, Naja RP. Vitamin D metabolism, cartilage and bone fracture repair. Mol Cell Endocrinol 2011; 347:48-54. [PMID: 21664253 DOI: 10.1016/j.mce.2011.05.018] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 04/26/2011] [Accepted: 05/02/2011] [Indexed: 12/19/2022]
Abstract
The 1,25-(OH)(2)D metabolite mediates the endocrine actions of vitamin D by regulating in the small intestine the expression of target genes that play a critical role in intestinal calcium absorption. The major role of the vitamin D hormone on bone is indirect and mediated through its endocrine function on mineral homeostasis. However, genetic manipulation of the expression of Cyp27b1 or the VDR in chondrocytes strongly support a direct role for locally synthesized 1,25(OH)(2)D, acting through the VDR, in vascular invasion and osteoclastogenesis during endochondral bone development. Cells from the growth plate respond to the 24,25-(OH)(2)D and 1,25-(OH)(2)D metabolites in a cell maturation-dependent manner and the effects of 1,25-(OH)(2)D are thought to be mediated through binding to the membrane-associated receptor PDIA3 (protein disulfide isomerase associated 3). The physiological relevance of membrane-mediated 1,25-(OH)(2)D signaling is emerging and is discussed. Finally, preliminary results suggest that mice deficient for Cyp24a1 exhibit a delay in bone fracture healing and support a role for 24,25-(OH)(2)D in mammalian fracture repair.
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Affiliation(s)
- René St-Arnaud
- Genetics Unit, Shriners Hospital for Children, Montreal, Quebec, Canada H3G 1A6.
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23
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Bell TD, Demay MB, Burnett-Bowie SAM. The biology and pathology of vitamin D control in bone. J Cell Biochem 2011; 111:7-13. [PMID: 20506379 DOI: 10.1002/jcb.22661] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Vitamin D is a steroid pro-hormone, whose active metabolite binds the vitamin D receptor (VDR) which, in turn, binds to DNA sequences on target genes as a heterodimer with the retinoid-X receptor, resulting in regulation of gene expression. The vitamin D pro-hormone can be synthesized in the skin, in response to ultraviolet radiation; however, dietary sources have become increasingly important as a result of cultural changes over the past few centuries. Based on its initial discovery as an anti-rachitic factor, studies of the role of vitamin D and its receptor have largely focused on the skeleton. Investigations into the pathophysiologic basis and therapeutic responses of skeletal disorders associated with impaired vitamin D action have led to the identification of the molecular pathways involved in hormone activation and regulation of gene expression by the liganded VDR. These studies have also demonstrated that the skeletal actions of the VDR and its ligand are largely redundant if normal mineral ion homeostasis can be maintained by other means. However, investigations in animal models with tissue-specific ablation of the VDR or the enzyme required for hormone activation have demonstrated novel actions in skeletal tissues. The active vitamin D metabolite has been shown to have both paracrine and endocrine actions in other tissues as well.
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Affiliation(s)
- Taison D Bell
- Department of Internal Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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24
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Majkova Z, Toborek M, Hennig B. The role of caveolae in endothelial cell dysfunction with a focus on nutrition and environmental toxicants. J Cell Mol Med 2011; 14:2359-70. [PMID: 20406324 PMCID: PMC2965309 DOI: 10.1111/j.1582-4934.2010.01064.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Complications of vascular diseases, including atherosclerosis, are the number one cause of death in Western societies. Dysfunction of endothelial cells is a critical underlying cause of the pathology of atherosclerosis. Lipid rafts, and especially caveolae, are enriched in endothelial cells, and down-regulation of the caveolin-1 gene may provide protection against the development of atherosclerosis. There is substantial evidence that exposure to environmental pollution is linked to cardiovascular mortality, and that persistent organic pollutants can markedly contribute to endothelial cell dysfunction and an increase in vascular inflammation. Nutrition can modulate the toxicity of environmental pollutants, and evidence suggests that these affect health and disease outcome associated with chemical insults. Because caveolae can provide a regulatory platform for pro-inflammatory signalling associated with vascular diseases such as atherosclerosis, we suggest a link between atherogenic risk and functional changes of caveolae by environmental factors such as dietary lipids and organic pollutants. For example, we have evidence that endothelial caveolae play a role in uptake of persistent organic pollutants, an event associated with subsequent production of inflammatory mediators. Functional properties of caveolae can be modulated by nutrition, such as dietary lipids (e.g. fatty acids) and plant-derived polyphenols (e.g. flavonoids), which change activation of caveolae-associated signalling proteins. The following review will focus on caveolae providing a platform for pro-inflammatory signalling, and the role of caveolae in endothelial cell functional changes associated with environmental mediators such as nutrients and toxicants, which are known to modulate the pathology of vascular diseases.
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Affiliation(s)
- Zuzana Majkova
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY, USA
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Chen J, Olivares-Navarrete R, Wang Y, Herman TR, Boyan BD, Schwartz Z. Protein-disulfide isomerase-associated 3 (Pdia3) mediates the membrane response to 1,25-dihydroxyvitamin D3 in osteoblasts. J Biol Chem 2010; 285:37041-50. [PMID: 20843786 DOI: 10.1074/jbc.m110.157115] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein-disulfide isomerase-associated 3 (Pdia3) is a multifunctional protein hypothesized to be a membrane receptor for 1,25(OH)(2)D(3). In intestinal epithelium and chondrocytes, 1,25(OH)(2)D(3) stimulates rapid membrane responses that are different from genomic effects via the vitamin D receptor (VDR). In this study, we show that 1,25(OH)(2)D(3) stimulates phospholipase A(2) (PLA(2))-dependent rapid release of prostaglandin E(2) (PGE(2)), activation of protein kinase C (PKC), and regulation of bone-related gene transcription and mineralization in osteoblast-like MC3T3-E1 cells (WT) via a mechanism involving Pdia3. Pdia3 was present in caveolae based on co-localization with lipid rafts and caveolin-1. In Pdia3-silenced (Sh-Pdia3) cells, 1,25(OH)(2)D(3) failed to stimulate PKC and PGE(2) responses; in Pdia3-overexpressing cells (Ov-Pdia3), responses to 1,25(OH)(2)D(3) were augmented. Downstream mediators of Pdia3, PLA(2)-activating protein (PLAA) and arachidonic acid, stimulated similar PKC activation in wild-type, Sh-Pdia3, and Ov-Pdia3 cells supporting the hypothesis that Pdia3 mediates the membrane action of 1,25(OH)(2)D(3). Treatment of MC3T3-E1 cells with 1,25(OH)(2)D(3) for 9 min stimulated rapid phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and increased expression of alkaline phosphatase, MMP-13, and osteopontin but decreased expression of osteocalcin, osteoprotegerin (mRNA and protein), and smad2. These effects were attenuated in Sh-Pdia3 cells. Sh-Pdia3 cells produced higher numbers of von Kossa-positive nodules and alizarin red-positive nodules compared with WT cells with or without 1,25(OH)(2)D(3) treatment whereas Ov-Pdia3 did not show any mineralization. Our data suggest Pdia3 is an important initiator of 1,25(OH)(2)D(3)-stimulated membrane signaling pathways, which have both genomic and non genomic effects during osteoblast maturation.
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Affiliation(s)
- Jiaxuan Chen
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0363, USA
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Wang Y, Chen J, Lee CSD, Nizkorodov A, Riemenschneider K, Martin D, Hyzy S, Schwartz Z, Boyan BD. Disruption of Pdia3 gene results in bone abnormality and affects 1alpha,25-dihydroxy-vitamin D3-induced rapid activation of PKC. J Steroid Biochem Mol Biol 2010; 121:257-60. [PMID: 20576531 DOI: 10.1016/j.jsbmb.2010.05.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 05/05/2010] [Accepted: 05/10/2010] [Indexed: 11/27/2022]
Abstract
1,25-dihydroxy-vitamin D3 [1alpha,25(OH)2D3] is a critical regulator of bone development. Protein disulfide isomerase A3 (Pdia3) is a multifunctional protein that has been associated with rapid membrane-initiated signalling by 1alpha,25(OH)2D3 in several cell types. To identify the physiological roles of Pdia3 in skeletal development, we generated Pdia3-deficient mice. No homozygous mice were observed at birth, indicating that the targeted disruption of the Pdia3 gene resulted in embryonic lethality. Pdia3 deficiency also resulted in skeletal manifestations as revealed by muCT analysis of femurs from 15-week-old heterozygous mice. The Pdia3+/- mice had increased metaphyseal bone volume and trabeculae compared to Pdia3+/+ mice. In contrast, the area and thickness of cortical bone at the femoral mid-diaphysis of Pdia3+/+ mice significantly exceeded that of Pdia3+/- mice. In vitro studies in osteoblast-like MC3T3-E1 cells showed that silencing of Pdia3 abolished 1alpha,25(OH)2D3-induced rapid activation of protein kinase C (PKC) while overexpression of Pdia3 resulted in augmentation of PKC activity by 1alpha,25(OH)2D3. Taken together, these data indicated that Pdia3 plays a crucial role in 1alpha,25(OH)2D3-regulated bone formation and the Pdia3-PKC signalling pathway might be involved in this process.
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Affiliation(s)
- Yun Wang
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
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27
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Lee CSD, Moyer HR, Gittens RAI, Williams JK, Boskey AL, Boyan BD, Schwartz Z. Regulating in vivo calcification of alginate microbeads. Biomaterials 2010; 31:4926-34. [PMID: 20363022 DOI: 10.1016/j.biomaterials.2010.03.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Accepted: 02/28/2010] [Indexed: 11/18/2022]
Abstract
Alginate calcification has been previously reported clinically and during animal implantation; however no study has investigated the mechanism, extensively characterized the mineral, or evaluated multiple methods to regulate or eliminate mineralization. In the present study, alginate calcification was first studied in vitro: calcium-crosslinked alginate beads sequestered surrounding phosphate while forming traces of hydroxyapatite. Calcification in vivo was then examined in nude mice using alginate microbeads with and without adipose stem cells (ASCs). Variables included the delivery method, site of delivery, sex of the animal, time in vivo, crosslinking solution, and method of storage prior to delivery. Calcium-crosslinked alginate microbeads mineralized when injected subcutaneously or implanted intramuscularly after 1-6 months. More extensive analysis with histology, microCT, FTIR, XRD, and EDS showed calcium phosphate deposits throughout the microbeads with surface mineralization that closely matched hydroxyapatite found in bone. Incorporating 25 mm bisphosphonate reduced alginate calcification whereas using barium chloride eliminated mineralization. Buffering the crosslinking solution with HEPES at pH 7.3 while washing and storing samples in basal media prior to implantation also eliminated calcification in vivo. This study shows that alginate processing prior to implantation can significantly influence bulk hydroxyapatite formation and presents a method to regulate alginate calcification.
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Affiliation(s)
- Christopher S D Lee
- Wallace H. Coulter Department of Biomedical Engineering and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA 30332-0363, USA
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28
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Nuclear translocation of the 1,25D3-MARRS (membrane associated rapid response to steroids) receptor protein and NFκB in differentiating NB4 leukemia cells. Exp Cell Res 2010; 316:1101-8. [DOI: 10.1016/j.yexcr.2010.01.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 12/30/2009] [Accepted: 01/05/2010] [Indexed: 11/23/2022]
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29
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Wang Y, Bella E, Lee CSD, Migliaresi C, Pelcastre L, Schwartz Z, Boyan BD, Motta A. The synergistic effects of 3-D porous silk fibroin matrix scaffold properties and hydrodynamic environment in cartilage tissue regeneration. Biomaterials 2010; 31:4672-81. [PMID: 20303584 DOI: 10.1016/j.biomaterials.2010.02.006] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2009] [Accepted: 02/02/2010] [Indexed: 11/30/2022]
Abstract
Autologous cell-based tissue engineering using three-dimensional porous scaffolds has provided a good option for the repair of cartilage defects. Silk fibroin-based scaffolds are naturally degradable materials with excellent biocompatibility and robust mechanical properties, indicating potential applications in cartilage tissue engineering. In this study, silk fibroin scaffolds prepared by freeze-drying (FD) and salt-leaching (SL300 and SL500) were fully characterized and used to study the effects of silk fibroin scaffold properties on chondrocyte attachment, proliferation and differentiation. The synergistic effects of scaffold properties and hydrodynamic environment generated by in vitro rocking culture were also investigated using static cultures as control. FD scaffolds with small pore size and lower porosity increased cell attachment but inhibited cell penetration and limited cell proliferation and differentiation. In contrast, SL scaffolds displaying a bigger pore size, higher porosity and crystallinity resulted in homogenous cell distribution, increasing cell proliferation and advanced chondrocyte differentiation in terms of their spherical morphology, predominant chondrogenic gene expression and abundant cartilaginous extracellular matrix production. A hydrodynamic environment was beneficial to chondrocyte proliferation, differentiation, and integrin gene expression in a pore size dependent manner with superior cartilage matrix production but limited hypertrophic differentiation obtained using chondrocyte-seeded SL500 scaffolds. Integrin alpha5beta1 might mediate these effects. Chondrocyte/SL500 silk fibroin constructs obtained under in vitro rocking culture might serve as an excellent implant for in vivo cartilage defect reparation.
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Affiliation(s)
- Yun Wang
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
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30
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The direct role of vitamin D on bone homeostasis. Arch Biochem Biophys 2008; 473:225-30. [PMID: 18424254 DOI: 10.1016/j.abb.2008.03.038] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 03/26/2008] [Accepted: 03/27/2008] [Indexed: 12/28/2022]
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Lee HJ, Ji Y, Paul S, Maehr H, Uskokovic M, Suh N. Activation of bone morphogenetic protein signaling by a Gemini vitamin D3 analogue is mediated by Ras/protein kinase C alpha. Cancer Res 2008; 67:11840-7. [PMID: 18089814 DOI: 10.1158/0008-5472.can-07-1549] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bone morphogenetic proteins (BMP) are members of the transforming growth factor-beta superfamily, and they play an important role for embryonic development, for bone and cartilage formation, and during carcinogenesis. We have previously shown that the novel Gemini vitamin D(3) analogue, Ro-438-3582 [Ro3582; 1 alpha,25-dihydroxy-20S,21(3-hydroxy-3-methylbutyl)-23-yne-26,27-hexafluorocholecalciferol], inhibited cell proliferation and activated the BMP/Smad signaling pathway in MCF10AT1 breast epithelial cells. In this report, we investigated the upstream signaling pathways responsible for the activation of BMP/Smad signaling by Ro3582. Among seven different serine/threonine kinase inhibitors that we tested, protein kinase C (PKC) inhibitors blocked the effects of Ro3582 on the phosphorylation of Smad1/5, mRNA synthesis for BMP-2 and BMP-6, and cell growth in MCF10AT1 cells. Overexpression of PKC alpha, but not PKC epsilon, PKC delta or PKC zeta isoforms, increased Ro3582-induced phosphorylation of Smad1/5, suggesting that PKC alpha mediates the activation of Smad signaling and inhibition of cell proliferation. Interestingly, the activation of Smad signaling by Ro3582 was shown in Ha-ras-transfected MCF10AT1 cells, but not in the parent cell line (MCF10A without Ras). Inhibiting Ras activity blocked the translocation of PKC alpha to the plasma membrane and the phosphorylation of Smad1/5 induced by Ro3582, indicating that Ras is necessary for the activation of PKC alpha and Smad signaling. In conclusion, Ro3582 inhibits cell proliferation and activates BMP/Smad signaling via a Ras and PKC alpha pathway in breast epithelial cells.
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Affiliation(s)
- Hong Jin Lee
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
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Rubin J, Schwartz Z, Boyan BD, Fan X, Case N, Sen B, Drab M, Smith D, Aleman M, Wong KL, Yao H, Jo H, Gross TS. Caveolin-1 knockout mice have increased bone size and stiffness. J Bone Miner Res 2007; 22:1408-18. [PMID: 17550335 DOI: 10.1359/jbmr.070601] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
UNLABELLED The skeletal phenotype of the cav-1(-/-) mouse, which lacks caveolae, was examined. muCT and histology showed increased trabecular and cortical bone caused by the gene deletion. Structural changes were accompanied by increased mechanical properties. Cell studies showed that cav-1 deficiency leads to increased osteoblast differentiation. These results suggest that cav-1 helps to maintain osteoblast progenitors in a less differentiated state. INTRODUCTION The absence of caveolin-1 in cellular membranes causes dysregulated signaling. To understand the role of the caveolar microdomain in bone homeostasis, we examined the skeletal phenotype of 5- and 8-wk-old cav-1(-/-) mice. MATERIALS AND METHODS High-resolution microCT imaging showed a region-specific effect of cav-1 deficiency on the skeleton. At 5 wk, cav-1(-/-) mice had increased epiphyseal bone volume (+58.4%, p = 0.05); at 8 wk, metaphyseal bone volume was increased by 77.4% (p = 0.008). Cortical bone at the femoral mid-diaphysis showed that the periosteal area of cav-1(-/-) mice significantly exceeded that of cav-1(+/+) mice by 23.9% and 16.3% at 5 and 8 wk, respectively, resulting in increased mechanical properties (I(max): +38.2%, p = 0.003 and I(mi): +23.7%, p = 0.03). RESULTS Histomorphometry complemented microCT results showing increased bone formation rate (BFR) at trabecular and cortical sites at 5 wk, which supported findings of increased bone at 8 wk in cav-1(-/-) mice. Formal mechanical testing of the femoral diaphysis confirmed increased bone structure: stiffness increased 33% and postyield deflection decreased 33%. Stromal cells from cav-1(-/-) marrow showed a 23% increase in von Kossa-positive nodules; osteoclastogenesis was also modestly increased in cav-1-deficient marrow. Knockdown of cav-1 with siRNA in wildtype stromal cells increased alkaline phosphatase protein and expression of osterix and Runx2, consistent with osteoblast differentiation. CONCLUSIONS These data suggest that cav-1 helps to maintain a less differentiated state of osteoblast progenitor cells, and the absence of cav-1 causes bone to mature more rapidly. Caveolin-1 may thus be a target for altering skeletal homeostasis.
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Affiliation(s)
- Janet Rubin
- Department of Medicine,University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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