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Yang J, Cong N, Shi D, Chen S, Zhang Z, Zhao P. Siwu decoction exerts a phytoestrogenic osteoprotective effect on postmenopausal osteoporosis via the estrogen receptor/phosphatidylinositol 3-kinase/serine/threonine protein kinase pathway. JOURNAL OF ETHNOPHARMACOLOGY 2024; 332:118366. [PMID: 38763371 DOI: 10.1016/j.jep.2024.118366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 04/13/2024] [Accepted: 05/17/2024] [Indexed: 05/21/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Siwu decoction (SWD) is widely used in gynecological diseases, such as peripheral menopause syndrome, premature ovarian failure, and menstrual disorder. However, the mechanism of SWD on postmenopausal osteoporosis (PMOP) remains unclear. AIM OF THE STUDY To discover the phytoestrogenic osteoprotective effect of SWD on PMOP. MATERIALS AND METHODS The potential mechanism of SWD on PMOP was filtered through network pharmacology research. The potential mechanism was verified in MC3T3-E1 cell lines in vitro. CCK8 assay was conducted to assess cell proliferation and the expressions of ER/PI3K/AKT pathway were analyzed using Western blot. Female F-344 rats were chosen to set up the PMOP model. The osteoprotective effect of SWD in vivo was evaluated using Hematoxylin-eosin staining, TRAP staining, Goldner staining and DXA. The potential mechanism was verified in vivo through Western blot and immunohistochemistry. RT-qPCR was conducted to unveil the expressions of osteogenesis genes. RESULTS Network pharmacology research showed that ER/PI3K/AKT pathway may be the potential mechanism of SWD on PMOP. SWD promoted the proliferation of osteoblasts and regulated the protein expressions of ER/PI3K/AKT pathway in vitro. SWD improved the morphological structure, bone mineralization and bone mineral density of femurs and suppressed osteoclastogenesis in PMOP rat model via ER/PI3K/AKT pathway in vivo. In addition, SWD regulated the mRNA expressions of osteogenesis-related genes. CONCLUSIONS SWD exerts a phytoestrogenic osteoprotective on PMOP by regulating ER/PI3K/AKT pathway, which marks it as a valuable medicine or supplement of PMOP.
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Affiliation(s)
- Jiadi Yang
- School of Life Sciences, Beijing University of Chinese Medicine, No.11 East Road, North 3rd Ring Road, Beijing, 100029, China.
| | - Nan Cong
- School of Life Sciences, Beijing University of Chinese Medicine, No.11 East Road, North 3rd Ring Road, Beijing, 100029, China; Department of Gynecology, The First Affiliated Hospital of Jinzhou Medical University, No.2, Section 5, Renmin Street, Guta District, Jinzhou, 121000, China.
| | - Danning Shi
- School of Life Sciences, Beijing University of Chinese Medicine, No.11 East Road, North 3rd Ring Road, Beijing, 100029, China.
| | - Si Chen
- School of Life Sciences, Beijing University of Chinese Medicine, No.11 East Road, North 3rd Ring Road, Beijing, 100029, China.
| | - Zeye Zhang
- School of Life Sciences, Beijing University of Chinese Medicine, No.11 East Road, North 3rd Ring Road, Beijing, 100029, China.
| | - Piwen Zhao
- School of Life Sciences, Beijing University of Chinese Medicine, No.11 East Road, North 3rd Ring Road, Beijing, 100029, China.
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2
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Pan T, Liu F, Hao X, Wang S, Wasi M, Song JH, Lewis VO, Lin PP, Moon B, Bird JE, Panaretakis T, Lin SH, Wu D, Farach-Carson MC, Wang L, Zhang N, An Z, Zhang XHF, Satcher RL. BIGH3 mediates apoptosis and gap junction failure in osteocytes during renal cell carcinoma bone metastasis progression. Cancer Lett 2024; 596:217009. [PMID: 38849015 DOI: 10.1016/j.canlet.2024.217009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 05/26/2024] [Accepted: 05/30/2024] [Indexed: 06/09/2024]
Abstract
Renal cell carcinoma (RCC) bone metastatis progression is driven by crosstalk between tumor cells and the bone microenvironment, which includes osteoblasts, osteoclasts, and osteocytes. RCC bone metastases (RCCBM) are predominantly osteolytic and resistant to antiresorptive therapy. The molecular mechanisms underlying pathologic osteolysis and disruption of bone homeostasis remain incompletely understood. We previously reported that BIGH3/TGFBI (transforming growth factor-beta-induced protein ig-h3, shortened to BIGH3 henceforth) secreted by colonizing RCC cells drives osteolysis by inhibiting osteoblast differentiation, impairing healing of osteolytic lesions, which is reversible with osteoanabolic agents. Here, we report that BIGH3 induces osteocyte apoptosis in both human RCCBM tissue specimens and in a preclinical mouse model. We also demonstrate that BIGH3 reduces Cx43 expression, blocking gap junction (GJ) function and osteocyte network communication. BIGH3-mediated GJ inhibition is blocked by the lysosomal inhibitor hydroxychloroquine (HCQ), but not osteoanabolic agents. Our results broaden the understanding of pathologic osteolysis in RCCBM and indicate that targeting the BIGH3 mechanism could be a combinational strategy for the treatment of RCCBM-induced bone disease that overcomes the limited efficacy of antiresorptives that target osteoclasts.
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Affiliation(s)
- Tianhong Pan
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Fengshuo Liu
- Departments of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Xiaoxin Hao
- Departments of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Shubo Wang
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Murtaza Wasi
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Jian H Song
- Departments of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Valerae O Lewis
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Patrick P Lin
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Bryan Moon
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Justin E Bird
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Theocharis Panaretakis
- Departments of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sue-Hwa Lin
- Departments of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; Departments of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Danielle Wu
- Department of Diagnostic and Biomedical Sciences, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX, USA; Departments of Bioengineering, Rice University, Houston, TX, USA
| | - Mary C Farach-Carson
- Department of Diagnostic and Biomedical Sciences, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX, USA; Departments of BioSciences, Rice University, Houston, TX, USA; Departments of Bioengineering, Rice University, Houston, TX, USA
| | - Liyun Wang
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Ningyan Zhang
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, USA
| | - Zhiqiang An
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, USA
| | - Xiang H-F Zhang
- Departments of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA; Departments of Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, USA; Departments of Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA; Departments of McNair Medical Institute, Baylor College of Medicine, Houston, TX, USA
| | - Robert L Satcher
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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3
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Ma L, Wang W, Xu G, Li H, Liu F, Shao H, Zhang X, Ma Y, Li G, Li H, Gao S, Ling P. Connexin 43 in the function and homeostasis of osteocytes: a narrative review. ANNALS OF JOINT 2023; 9:10. [PMID: 38529291 PMCID: PMC10929443 DOI: 10.21037/aoj-23-65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 11/29/2023] [Indexed: 03/27/2024]
Abstract
Background and Objective Connexin 43 (Cx43) is the main gap junction (GJ) protein and hemichannel protein in bone tissue. It is involved in the formation of hemichannels and GJs and establishes channels that can communicate directly to exchange substances and signals, affecting the structure and function of osteocytes. CX43 is very important for the normal development of bone tissue and the establishment and balance of bone reconstruction. However, the molecular mechanisms by which CX43 regulates osteoblast function and homeostasis have been less well studied, and this article provides a review of research in this area. Methods We searched the PubMed, EMBASE, Cochrane Library, and Web of Science databases for studies published up to June 2023 using the keywords Connexin 43/Cx43 and Osteocytes. Screening of literatures according to inclusion and exclusion guidelines and summarized the results. Key Content and Findings Osteocytes, osteoblasts, and osteoclasts all express Cx43 and form an overall network through the interaction between GJs. Cx43 is not only involved in the mechanical response of bone tissue but also in the regulation of signal transduction, which could provide new molecular markers and novel targets for the treatment of certain bone diseases. Conclusions Cx43 is expressed in osteoblasts, osteoclasts, and osteoclasts and plays an important role in regulating the function, signal transduction, and mechanotransduction of osteocytes. This review offers a new contribution to the literature by summarizing the relationship between Cx43, a key protein of bone tissue, and osteoblasts.
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Affiliation(s)
- Liang Ma
- Department of Orthopedics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
- Post-doctoral Station of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Wenzhao Wang
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Guixuan Xu
- Department of Pathology and Medical Research Center, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Hao Li
- Department of Joint Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Fei Liu
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
| | - Huarong Shao
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
| | - Xiuhua Zhang
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
| | - Yuxia Ma
- Post-doctoral Station of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Gang Li
- Department of Orthopedics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Hui Li
- Department of Operating Room, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Shuzhong Gao
- Post-doctoral Station of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Peixue Ling
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
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4
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Plotkin LI, Asad I, Kritikos AE, Sanz N. Role of Cx43 on the Bone Cell Generation, Function, and Survival. Bioelectricity 2023; 5:188-195. [PMID: 37746312 PMCID: PMC10517329 DOI: 10.1089/bioe.2023.0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2023] Open
Abstract
The presence of gap junction intercellular communication structures in bone cells has been known since the early 1970s, further confirmed by Doty and Marotti at the structural level in the 1980-1990s. Work by Civitelli, Donahue, and others showed the expression of Cx43 at the mRNA and protein levels in all bone cell types: osteoclasts (bone resorbing cells), osteoblasts (bone forming cells), and osteocytes (mature osteoblasts embedded in the bone matrix that regulate the function of both osteoclasts and osteoblasts). While Cx45, Cx46, and Cx37 were also shown to be expressed in bone cells, most studies have focused on Cx43, the most abundant member of the connexin (Cx) family of proteins expressed in bone. The role of Cx43 has been shown to be related to the formation of gap junction intercellular channels, to unopposed hemichannels, and to channel independent functions of the molecule. Cx43 participates in the response of bone cells to pharmacological, hormonal, and mechanical stimuli, and it is involved in the skeletal phenotype with old age. Human and murine studies have shown that mutations of Cx43 lead to oculodentodigital dysplasia and craniometaphyseal dysplasia, both conditions associated with abnormalities in the skeleton. However, whereas substantial advances have been made on the skeletal role of Cx43, further research is needed to understand the basis for the effects of mutated Cx43 and potential ways to prevent the effects of these mutations on bone.
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Affiliation(s)
- Lilian I. Plotkin
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Roudebush Veterans Administration Medical Center, Indianapolis, Indiana, USA
- Indiana Center for Musculoskeletal Health, Indianapolis, Indiana, USA
| | - Iqra Asad
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Alex E. Kritikos
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Natasha Sanz
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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5
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Xu J, Cao B, Li C, Li G. The recent progress of endocrine therapy-induced osteoporosis in estrogen-positive breast cancer therapy. Front Oncol 2023; 13:1218206. [PMID: 37483519 PMCID: PMC10361726 DOI: 10.3389/fonc.2023.1218206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 06/23/2023] [Indexed: 07/25/2023] Open
Abstract
Breast cancer is a significant global health concern, and the discovery of endocrine therapy has played a crucial role in the treatment of estrogen-positive breast cancer. However, these therapies are often associated with osteoporosis-related adverse events, which increase the risk of fractures in breast cancer patients and can result in limited mobility and reduced quality of life. Previous studies have shown that osteoporosis is essential side effects of the breast cancer therapy, although the exact mechanisms remain mostly unclear. Current clinical treatments, such as bisphosphonates, cause side effects and may impact the therapeutic response to endocrine drugs. In this review, we explore the likelihood of endocrine therapy-induced osteoporosis in estrogen-positive breast cancer therapy and discuss the involved mechanisms as well as the therapeutic potential of drugs and drug combination strategies.
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Affiliation(s)
| | | | - Chunyu Li
- *Correspondence: Chunyu Li, ; Guohui Li,
| | - Guohui Li
- *Correspondence: Chunyu Li, ; Guohui Li,
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Mao L, Wang L, Xu J, Zou J. The role of integrin family in bone metabolism and tumor bone metastasis. Cell Death Discov 2023; 9:119. [PMID: 37037822 PMCID: PMC10086008 DOI: 10.1038/s41420-023-01417-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 04/12/2023] Open
Abstract
Integrins have been the research focus of cell-extracellular matrix adhesion (ECM) and cytokine receptor signal transduction. They are involved in the regulation of bone metabolism of bone precursor cells, mesenchymal stem cells (MSCs), osteoblasts (OBs), osteoclasts (OCs), and osteocytes. Recent studies expanded and updated the role of integrin in bone metabolism, and a large number of novel cytokines were found to activate bone metabolism pathways through interaction with integrin receptors. Integrins act as transducers that mediate the regulation of bone-related cells by mechanical stress, fluid shear stress (FSS), microgravity, hypergravity, extracellular pressure, and a variety of physical factors. Integrins mediate bone metastasis of breast, prostate, and lung cancer by promoting cancer cell adhesion, migration, and survival. Integrin-mediated targeted therapy showed promising prospects in bone metabolic diseases. This review emphasizes the latest research results of integrins in bone metabolism and bone metastasis and provides a vision for treatment strategies.
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Affiliation(s)
- Liwei Mao
- School of Kinesiology, Shanghai University of Sport, 200438, Shanghai, China
| | - Lian Wang
- School of Kinesiology, Shanghai University of Sport, 200438, Shanghai, China
| | - Jiake Xu
- School of Biomedical Sciences, The University of Western Australia, WA, 6009, Perth, Australia
| | - Jun Zou
- School of Kinesiology, Shanghai University of Sport, 200438, Shanghai, China.
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7
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Yang J, Liu L, Oda Y, Wada K, Ago M, Matsuda S, Hattori M, Goto T, Kawashima Y, Matsuzaki Y, Taketani T. Highly-purified rapidly expanding clones, RECs, are superior for functional-mitochondrial transfer. Stem Cell Res Ther 2023; 14:40. [PMID: 36927781 PMCID: PMC10022310 DOI: 10.1186/s13287-023-03274-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
BACKGROUND Mitochondrial dysfunction caused by mutations in mitochondrial DNA (mtDNA) or nuclear DNA, which codes for mitochondrial components, are known to be associated with various genetic and congenital disorders. These mitochondrial disorders not only impair energy production but also affect mitochondrial functions and have no effective treatment. Mesenchymal stem cells (MSCs) are known to migrate to damaged sites and carry out mitochondrial transfer. MSCs grown using conventional culture methods exhibit heterogeneous cellular characteristics. In contrast, highly purified MSCs, namely the rapidly expanding clones (RECs) isolated by single-cell sorting, display uniform MSCs functionality. Therefore, we examined the differences between RECs and MSCs to assess the efficacy of mitochondrial transfer. METHODS We established mitochondria-deficient cell lines (ρ0 A549 and ρ0 HeLa cell lines) using ethidium bromide. Mitochondrial transfer from RECs/MSCs to ρ0 cells was confirmed by PCR and flow cytometry analysis. We examined several mitochondrial functions including ATP, reactive oxygen species, mitochondrial membrane potential, and oxygen consumption rate (OCR). The route of mitochondrial transfer was identified using inhibition assays for microtubules/tunneling nanotubes, gap junctions, or microvesicles using transwell assay and molecular inhibitors. RESULTS Co-culture of ρ0 cells with MSCs or RECs led to restoration of the mtDNA content. RECs transferred more mitochondria to ρ0 cells compared to that by MSCs. The recovery of mitochondrial function, including ATP, OCR, mitochondrial membrane potential, and mitochondrial swelling in ρ0 cells co-cultured with RECs was superior than that in cells co-cultured with MSCs. Inhibition assays for each pathway revealed that RECs were sensitive to endocytosis inhibitor, dynasore. CONCLUSIONS RECs might serve as a potential therapeutic strategy for diseases linked to mitochondrial dysfunction by donating healthy mitochondria.
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Affiliation(s)
- Jiahao Yang
- Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1, Enya, Izumo, Shimane, 693-8501, Japan
| | - Lu Liu
- Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1, Enya, Izumo, Shimane, 693-8501, Japan.,Faculty of Nursing, Inner Mongolia Medical University, Hohhot, Inner Mongolia, China
| | - Yasuaki Oda
- Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1, Enya, Izumo, Shimane, 693-8501, Japan
| | - Keisuke Wada
- Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1, Enya, Izumo, Shimane, 693-8501, Japan
| | - Mako Ago
- Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1, Enya, Izumo, Shimane, 693-8501, Japan
| | - Shinichiro Matsuda
- Department of Medical Oncology, Shimane University Hospital, Izumo, Shimane, Japan
| | - Miho Hattori
- Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1, Enya, Izumo, Shimane, 693-8501, Japan
| | - Tsukimi Goto
- Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1, Enya, Izumo, Shimane, 693-8501, Japan
| | - Yuki Kawashima
- Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1, Enya, Izumo, Shimane, 693-8501, Japan
| | - Yumi Matsuzaki
- Department of Life Science, Faculty of Medicine, Shimane University, Izumo, Shimane, Japan
| | - Takeshi Taketani
- Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1, Enya, Izumo, Shimane, 693-8501, Japan.
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Li G, Zhang L, Lu Z, Yang B, Yang H, Shang P, Jiang JX, Wang D, Xu H. Connexin 43 Channels in Osteocytes Are Necessary for Bone Mass and Skeletal Muscle Function in Aged Male Mice. Int J Mol Sci 2022; 23:13506. [PMID: 36362291 PMCID: PMC9654692 DOI: 10.3390/ijms232113506] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/24/2022] [Accepted: 11/03/2022] [Indexed: 09/26/2023] Open
Abstract
Osteoporosis and sarcopenia (termed "Osteosarcopenia"), the twin-aging diseases, are major contributors to reduced bone mass and muscle weakness in the elderly population. Connexin 43 (Cx43) in osteocytes has been previously reported to play vital roles in bone homeostasis and muscle function in mature mice. The Cx43-formed gap junctions (GJs) and hemichannels (HCs) in osteocytes are important portals for the exchange of small molecules in cell-to-cell and cell-to-extracellular matrix, respectively. However, the roles of Cx43-based GJs and HCs in both bone and muscle aging are still unclear. Here, we used two transgenic mouse models with overexpression of the dominant negative Cx43 mutants primarily in osteocytes driven by the 10-kb Dmp1 promoter, R76W mice (inhibited gap junctions but enhanced hemichannels) and Δ130-136 mice (both gap junction and hemichannels are inhibited), to determine the actions of Cx43-based hemichannels (HCs) and gap junctions (GJs) in the regulation of bone and skeletal muscle from aged mice (18 months) as compared with those from adult mice (10 months). We demonstrated that enhancement of Cx43 HCs reduces bone mass due to increased osteoclast surfaces while the impairment of Cx43 HCs increases osteocyte apoptosis in aged mice caused by reduced PGE2 levels. Furthermore, altered mitochondrial homeostasis with reduced expression of Sirt-1, OPA-1, and Drp-1 resulted in excessive ROS level in muscle soleus (SL) of aged transgenic mice. In vitro, the impairment of Cx43 HCs in osteocytes from aged mice also promoted muscle collagen synthesis through activation of TGFβ/smad2/3 signaling because of reduced PGE2 levels in the PO CM. These findings indicate that the enhancement of Cx43 HCs while GJs are inhibited reduces bone mass, and the impairment of Cx43 HCs inhibits PGE2 level in osteocytes and this reduction promotes muscle collagen synthesis in skeletal muscle through activation of TGFβ/smad2/3 signaling, which together with increased ROS level contributes to reduced muscle force in aged mice.
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Affiliation(s)
- Guobin Li
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
- College of Life Sciences, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Lan Zhang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Zhe Lu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Baoqiang Yang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Hui Yang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Peng Shang
- Key Laboratory for Space Bioscience and Biotechnology, Research and Development Institute in Shenzhen, Northwestern Polytechnical University, Shenzhen 518057, China
| | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Dong’en Wang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Huiyun Xu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
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9
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Zhao D, Hua R, Riquelme MA, Cheng H, Guda T, Xu H, Gu S, Jiang JX. Osteocytes regulate bone anabolic response to mechanical loading in male mice via activation of integrin α5. Bone Res 2022; 10:49. [PMID: 35851577 PMCID: PMC9293884 DOI: 10.1038/s41413-022-00222-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 05/25/2022] [Accepted: 06/13/2022] [Indexed: 12/18/2022] Open
Abstract
Physical mechanical stimulation can maintain and even increase bone mass. Here, we report an important role of osteocytic integrin α5 in regulating the anabolic response of bone to mechanical loading using an Itga5 conditional gene knockout (cKO) mouse model. Integrin α5 gene deletion increased apoptotic osteocytes and reduced cortical anabolic responses to tibial compression including decreased endosteal osteoblasts and bone formation, and increased endosteal osteoclasts and bone resorption, contributing to the decreased bone area fraction and biomechanical properties, leading to an enlarged bone marrow area in cKO mice. Similar disruption of anabolic responses to mechanical loading was also detected in cKO trabecular bone. Moreover, integrin α5 deficiency impeded load-induced Cx43 hemichannel opening, and production and release of PGE2, an anabolic factor, resulting in attenuated effects of the loading on catabolic sclerostin (SOST) reduction and anabolic β-catenin increase. Together, this study shows an indispensable role of integrin α5 in osteocytes in the anabolic action of mechanical loading on skeletal tissue through activation of hemichannels and PGE2-evoked gene expression. Integrin α5 could act as a potential new therapeutic target for bone loss, especially in the elderly population with impeded mechanical sensitivity.
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Affiliation(s)
- Dezhi Zhao
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Rui Hua
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Manuel A Riquelme
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Hongyun Cheng
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Teja Guda
- Department of Biomedical Engineering and Chemical Engineering, University of Texas, San Antonio, TX, USA
| | - Huiyun Xu
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Sumin Gu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA.
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10
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Bolamperti S, Villa I, Rubinacci A. Bone remodeling: an operational process ensuring survival and bone mechanical competence. Bone Res 2022; 10:48. [PMID: 35851054 PMCID: PMC9293977 DOI: 10.1038/s41413-022-00219-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 05/02/2022] [Accepted: 05/15/2022] [Indexed: 12/12/2022] Open
Abstract
Bone remodeling replaces old and damaged bone with new bone through a sequence of cellular events occurring on the same surface without any change in bone shape. It was initially thought that the basic multicellular unit (BMU) responsible for bone remodeling consists of osteoclasts and osteoblasts functioning through a hierarchical sequence of events organized into distinct stages. However, recent discoveries have indicated that all bone cells participate in BMU formation by interacting both simultaneously and at different differentiation stages with their progenitors, other cells, and bone matrix constituents. Therefore, bone remodeling is currently considered a physiological outcome of continuous cellular operational processes optimized to confer a survival advantage. Bone remodeling defines the primary activities that BMUs need to perform to renew successfully bone structural units. Hence, this review summarizes the current understanding of bone remodeling and future research directions with the aim of providing a clinically relevant biological background with which to identify targets for therapeutic strategies in osteoporosis.
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Affiliation(s)
- Simona Bolamperti
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Isabella Villa
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Alessandro Rubinacci
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy.
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11
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Fernández-Olivares A, Durán-Jara E, Verdugo DA, Fiori MC, Altenberg GA, Stehberg J, Alfaro I, Calderón JF, Retamal MA. Extracellular Cysteines Are Critical to Form Functional Cx46 Hemichannels. Int J Mol Sci 2022; 23:7252. [PMID: 35806258 PMCID: PMC9266770 DOI: 10.3390/ijms23137252] [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: 05/10/2022] [Revised: 06/16/2022] [Accepted: 06/18/2022] [Indexed: 12/10/2022] Open
Abstract
Connexin (Cxs) hemichannels participate in several physiological and pathological processes, but the molecular mechanisms that control their gating remain elusive. We aimed at determining the role of extracellular cysteines (Cys) in the gating and function of Cx46 hemichannels. We studied Cx46 and mutated all of its extracellular Cys to alanine (Ala) (one at a time) and studied the effects of the Cys mutations on Cx46 expression, localization, and hemichannel activity. Wild-type Cx46 and Cys mutants were expressed at comparable levels, with similar cellular localization. However, functional experiments showed that hemichannels formed by the Cys mutants did not open either in response to membrane depolarization or removal of extracellular divalent cations. Molecular-dynamics simulations showed that Cys mutants may show a possible alteration in the electrostatic potential of the hemichannel pore and an altered disposition of important residues that could contribute to the selectivity and voltage dependency in the hemichannels. Replacement of extracellular Cys resulted in "permanently closed hemichannels", which is congruent with the inhibition of the Cx46 hemichannel by lipid peroxides, through the oxidation of extracellular Cys. These results point to the modification of extracellular Cys as potential targets for the treatment of Cx46-hemichannel associated pathologies, such as cataracts and cancer, and may shed light into the gating mechanisms of other Cx hemichannels.
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Affiliation(s)
- Ainoa Fernández-Olivares
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile; (A.F.-O.); (I.A.)
| | - Eduardo Durán-Jara
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile;
| | - Daniel A. Verdugo
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 7780272, Chile; (D.A.V.); (J.S.)
| | - Mariana C. Fiori
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6551, USA; (M.C.F.); (G.A.A.)
| | - Guillermo A. Altenberg
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6551, USA; (M.C.F.); (G.A.A.)
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 7780272, Chile; (D.A.V.); (J.S.)
| | - Iván Alfaro
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile; (A.F.-O.); (I.A.)
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago 7690000, Chile
| | - Juan Francisco Calderón
- Centro de Genética y Genómica, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile
| | - Mauricio A. Retamal
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile; (A.F.-O.); (I.A.)
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago 7690000, Chile
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7690000, Chile
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12
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Tao ZS, Li TL, Wei S. Probucol promotes osteoblasts differentiation and prevents osteoporosis development through reducing oxidative stress. Mol Med 2022; 28:75. [PMID: 35764958 PMCID: PMC9238135 DOI: 10.1186/s10020-022-00503-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 06/21/2022] [Indexed: 12/13/2022] Open
Abstract
Probucol (PBC) is a potent cholesterol-lowering drug and has been studied extensively for its powerful antioxidative stress. The purpose of this study is to investigate the role of PBC in ovariectomized rat model and to explore the mechanism of osteogenic differentiation of MC3TE-E1 Cells. RT-qPCR and Immunofluorescence were used to measure the expression level of SOD2, SIRT1, intracellular oxidative stress levels and osteogenic markers proteins. Moreover, CCK-8 assay was conducted to detect cell viability. Alizarin red staining and alkaline phosphatase staining were applied to examine osteogenic function and calcium deposits. The ovariectomized rat model was set up successfully and HE staining were employed to examine femoral trabeculae tissue. Our results showed that PBC suppressed MC3TE-E1 resist oxidative stress to promote osteogenic differentiation. Additionally, it was confirmed that PBC promoted osteogenic differentiation of MC3TE-E1 through inhibiting oxidative stress. Further study indicated that PBC exerted its beneficial function by suppressing oxidative stress-mediated alter bone metabolism to alleviate osteoporosis in vivo. Our research suggested that the PBC-modulated oxidative stress inhibition is responsible for activation of the process of osteogenic differentiation, providing a novel insight into the treatment of osteoporosis.
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Affiliation(s)
- Zhou-Shan Tao
- Department of Orthopedics, The First Affiliated Hospital of Wannan Medical College, Yijishan Hospital, No. 2, Zhe Shan Xi Road, Wuhu, 241001, Anhui, People's Republic of China.
| | - Tian-Lin Li
- Department of Orthopedics, The First Affiliated Hospital of Wannan Medical College, Yijishan Hospital, No. 2, Zhe Shan Xi Road, Wuhu, 241001, Anhui, People's Republic of China
| | - Shan Wei
- School of Mechanical Engineering, Anhui Polytechnic University, Wuhu, 241000, People's Republic of China.,Additive Manufacturing Institute of Anhui Polytechnic University, Anhui Polytechnic University, Wuhu, 241000, People's Republic of China
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13
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Hua R, Gu S, Jiang JX. Connexin 43 Hemichannels Regulate Osteoblast to Osteocyte Differentiation. Front Cell Dev Biol 2022; 10:892229. [PMID: 35693933 PMCID: PMC9184820 DOI: 10.3389/fcell.2022.892229] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022] Open
Abstract
Connexin 43 (Cx43) is the predominant connexin subtype expressed in osteocytes. Osteocytes, accounting for 90%–95% of total bone cells, function as orchestrators coordinating balanced activity between bone-resorbing osteoclasts and bone-forming osteoblasts. In this study, two newly developed osteocytic cell lines, OCY454 and IDG-SW3, were used to determine the role of Cx43 gap junctions and hemichannels (HCs) in the regulation of osteoblast to osteocyte differentiation. We found that the Cx43 level was substantially increased during the differentiation of IDG-SW3 cells and is also much higher than that of OCY454 cells. We knocked down Cx43 expression using the lentiviral CRISPR/Cas9 approach and inhibition of Cx43 HCs using Cx43 (E2) antibody in IDG-SW3 cells. Cx43 knockdown (KD) or Cx43 HC inhibition decreased gene expression for osteoblast and osteocyte markers, including alkaline phosphatase, type I collagen, dentin matrix protein 1, sclerostin, and fibroblast growth factor 23, whereas increasing the osteoclastogenesis indicator and the receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) ratio at early and late differentiation stages. Moreover, mineralization was remarkably attenuated in differentiated Cx43-deficient IDG-SW3 cells compared to ROSA26 control. The conditioned medium collected from fully differentiated IDG-SW3 cells with Cx43 KD promoted osteoclastogenesis of RAW264.7 osteoclast precursors. Our results demonstrated that Cx43 HCs play critical roles in osteoblast to osteocyte differentiation process and regulate osteoclast differentiation via secreted factors.
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14
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An S, Zheng S, Cai Z, Chen S, Wang C, Li Y, Deng Z. Connexin43 in Musculoskeletal System: New Targets for Development and Disease Progression. Aging Dis 2022; 13:1715-1732. [DOI: 10.14336/ad.2022.0421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/21/2022] [Indexed: 11/18/2022] Open
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15
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Osteocytic Connexin Hemichannels Modulate Oxidative Bone Microenvironment and Breast Cancer Growth. Cancers (Basel) 2021; 13:cancers13246343. [PMID: 34944962 PMCID: PMC8699531 DOI: 10.3390/cancers13246343] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 11/16/2022] Open
Abstract
Osteocytes, the most abundant bone cell types embedded in the mineral matrix, express connexin 43 (Cx43) hemichannels that play important roles in bone remodeling and osteocyte survival. Estrogen deficiency decreases osteocytic Cx43 hemichannel activity and causes a loss in osteocytes' resistance to oxidative stress (OS). In this study, we showed that OS reduced the growth of both human (MDA-MB-231) and murine (Py8119) breast cancer cells. However, co-culturing these cells with osteocytes reduced the inhibitory effect of OS on breast cancer cells, and this effect was ablated by the inhibition of Cx43 hemichannels. Py8119 cells were intratibially implanted in the bone marrow of ovariectomized (OVX) mice to determine the role of osteocytic Cx43 hemichannels in breast cancer bone metastasis in response to OS. Two transgenic mice overexpressing dominant-negative Cx43 mutants, R76W and Δ130-136, were adopted for this study; the former inhibits gap junctions while the latter inhibits gap junctions and hemichannels. Under normal conditions, Δ130-136 mice had significantly more tumor growth in bone than that in WT and R76W mice. OVX increased tumor growth in R76W but had no significant effect on WT mice. In contrast, OVX reduced tumor growth in Δ130-136 mice. To confirm the role of OS, WT and Δ130-136 mice were administered the antioxidant N-acetyl cysteine (NAC). NAC increased tumor burden and growth in Δ130-136 mice but not in WT mice. Together, the data suggest that osteocytes and Cx43 hemichannels play pivotal roles in modulating the oxidative microenvironment and breast cancer growth in the bone.
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16
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Reis J, Ramos A. In Sickness and in Health: The Oxygen Reactive Species and the Bone. Front Bioeng Biotechnol 2021; 9:745911. [PMID: 34888300 PMCID: PMC8650620 DOI: 10.3389/fbioe.2021.745911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 10/28/2021] [Indexed: 12/30/2022] Open
Abstract
Oxidative stress plays a central role in physiological and pathological bone conditions. Its role in signalment and control of bone cell population differentiation, activity, and fate is increasingly recognized. The possibilities of its use and manipulation with therapeutic goals are virtually unending. However, how redox balance interplays with the response to mechanical stimuli is yet to be fully understood. The present work summarizes current knowledge on these aspects, in an integrative and broad introductory perspective.
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Affiliation(s)
- Joana Reis
- Agronomic and Veterinary Sciences, School of Agriculture, Polytechnic Institute of Viana Do Castelo, Ponte de Lima, Portugal
| | - António Ramos
- TEMA, Mechanical Engineering Department, University of Aveiro, Aveiro, Portugal
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17
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Misiakiewicz-Has K, Pilutin A, Wiszniewska B. Influence of hormonal imbalance on the integrity of seminiferous epithelium in the testes of adult rats chronically exposed to letrozole and rats exposed to soya isoflavones during the prenatal period, lactation, and up to sexual maturity. Reprod Biol 2021; 21:100562. [PMID: 34555686 DOI: 10.1016/j.repbio.2021.100562] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 11/21/2022]
Abstract
The structural integrity of the germ cells in the seminiferous epithelium and the correct process of spermatogenesis are made possible by proteins that participate in the formation of different types of junctions. This study was performed on samples of the testes of 4 groups (2 experimental and 2 corresponding control) of male Wistar rats. In the first experimental group, the adult rats received letrozole - a nonsteroidal inhibitor of cytochrome P450 aromatase (P450arom). The second experimental group was exposed to soya isoflavones during the prenatal period, lactation, and up to sexual maturity. The aim of this study was to examine the immunoexpression of β-catenin, N-cadherin, occludin, connexin43, annexin V, and advanced glycation end products (AGE) in the seminiferous epithelium of rat testes with chronic estrogen deficiency and of rats exposed to soya isoflavones. Series of sections of the testes were stained using PAS and silver impregnation. Moreover, immunohistochemistry tests were performed. A semi-quantitative determination of protein immunoexpression was performed using Image J. The number of annexin V positive Sertoli cells per tubule were counted manually. Comparisons between the experimental and corresponding control groups were performed using a non-parametric Mann-Whitney U test. The most common alterations were prematurely sloughed germ cells in the lumen of the seminiferous tubules and invaginations of the seminiferous tubules. We observed a lower number of annexin V positive Sertoli cells and a lower expression of N-cadherin and occludin in the seminiferous epithelium of both groups of rats with hormonal imbalances. Moreover, a higher expression of AGE, a lower expression of connexin 43 and a lower amount of reticular fibers in the basal lamina of seminiferous tubules was present in rats treated with letrozole and a higher expression of β-catenin was found in rats exposed to soya isoflavones. The hormonal imbalance between androgens and estrogens resulted in a decreased number of annexin V positive Sertoli cells. This may be associated with a failed clearance of apoptotic germ cells that leads to disturbances in the blood-testis-barrier (BTB) by affecting the expression of junctional proteins in the seminiferous epithelium. Moreover, a decreased level of estrogens was also associated with an increased expression of AGEs and with a changed composition of basal lamina in the seminiferous tubules of rats. These changes could lead to germ cell sloughing and invaginations of the seminiferous tubules.
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Affiliation(s)
- K Misiakiewicz-Has
- Department of Histology and Embryology, Pomeranian Medical University in Szczecin, 70-111, Szczecin, Poland.
| | - A Pilutin
- Department of Histology and Embryology, Pomeranian Medical University in Szczecin, 70-111, Szczecin, Poland
| | - B Wiszniewska
- Department of Histology and Embryology, Pomeranian Medical University in Szczecin, 70-111, Szczecin, Poland
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18
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Lewis KJ, Cabahug-Zuckerman P, Boorman-Padgett JF, Basta-Pljakic J, Louie J, Stephen S, Spray DC, Thi MM, Seref-Ferlengez Z, Majeska RJ, Weinbaum S, Schaffler MB. Estrogen depletion on In vivo osteocyte calcium signaling responses to mechanical loading. Bone 2021; 152:116072. [PMID: 34171514 PMCID: PMC8316427 DOI: 10.1016/j.bone.2021.116072] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/15/2021] [Accepted: 06/20/2021] [Indexed: 11/27/2022]
Abstract
Microstructural adaptation of bone in response to mechanical stimuli is diminished with estrogen deprivation. Here we tested in vivo whether ovariectomy (OVX) alters the acute response of osteocytes, the principal mechanosensory cells of bone, to mechanical loading in mice. We also used super resolution microscopy (Structured Illumination microscopy or SIM) in conjunction with immunohistochemistry to assess changes in the number and organization of "osteocyte mechanosomes" - complexes of Panx1 channels, P2X7 receptors and CaV3 voltage-gated Ca2+ channels clustered around αvβ3 integrin foci on osteocyte processes. Third metatarsals bones of mice expressing an osteocyte-targeted genetically encoded Ca2+ indicator (DMP1-GCaMP3) were cyclically loaded in vivo to strains from 250 to 3000 με and osteocyte intracellular Ca2+ signaling responses were assessed in mid-diaphyses using multiphoton microscopy. The number of Ca2+ signaling osteocytes in control mice increase monotonically with applied strain magnitude for the physiological range of strains. The relationship between the number of Ca2+ signaling osteocytes and loading was unchanged at 2 days post-OVX. However, it was altered markedly at 28 days post-OVX. At loads up to 1000 με, there was a dramatic reduction in number of responding (i.e. Ca2+ signaling) osteocytes; however, at higher strains the numbers of Ca2+ signaling osteocytes were similar to control mice. OVX significantly altered the abundance, make-up and organization of osteocyte mechanosome complexes on dendritic processes. Numbers of αvβ3 foci also staining with either Panx 1, P2X7R or CaV3 declined by nearly half after OVX, pointing to a loss of osteocyte mechanosomes on the dendritic processes with estrogen depletion. At the same time, the areas of the remaining foci that stained for αvβ3 and channel proteins increased significantly, a redistribution of mechanosome components suggesting a potential compensatory response. These results demonstrate that the deleterious effects of estrogen depletion on skeletal mechanical adaptation appear at the level of mechanosensation; osteocytes lose the ability to sense small (physiological) mechanical stimuli. This decline may result at least partly from changes in the structure and organization of osteocyte mechanosomes, which contribute to the distinctive sensitivity of osteocytes (particularly their dendritic processes) to mechanical stimulation.
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Affiliation(s)
- Karl J Lewis
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States of America
| | - Pamela Cabahug-Zuckerman
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States of America
| | - James F Boorman-Padgett
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States of America
| | - Jelena Basta-Pljakic
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States of America
| | - Joyce Louie
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States of America
| | - Samuel Stephen
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States of America
| | - David C Spray
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Mia M Thi
- Orthopaedic Surgery, Albert Einstein College of Medicine, Bronx, NY, United States of America; Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Zeynep Seref-Ferlengez
- Orthopaedic Surgery, Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Robert J Majeska
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States of America
| | - Sheldon Weinbaum
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States of America
| | - Mitchell B Schaffler
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States of America.
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19
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Chen JH, Shen C, Oh H, Park JH. Exendin-4, a glucagon-like peptide receptor agonist, facilitates osteoblast differentiation via connexin43. Endocrine 2021; 72:672-680. [PMID: 33641073 DOI: 10.1007/s12020-021-02664-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/17/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate whether exendin-4 (Ex-4), a glucagon-like peptide 1 receptor (GLP-1R) agonist, affects connexin 43 (Cx43) expression in osteoblasts, and determine the specific mechanism underlying Cx43 modulation by Ex-4. METHODS Osteoblast-like MC3T3-E1 cells were treated with Ex-4 with or without GLP-1R antagonist. We assessed Cx43 expression using RT-PCR, western blotting, and confocal microscopy; visualized intercellular communication using Lucifer yellow dye transfer assay; evaluated osteoblast differentiation using alkaline phosphatase and Alizarin red S (ARS) staining. Cx43 silencing or overexpression was investigated via RNA-interference or adenovirus infection. The mechanism underlying Cx43 regulation by Ex-4 was determined via treatment with either Src kinase inhibitor, KX2-391, Akt activator, sc79, or inhibitor, LY294002. RESULTS Ex-4 treatment enhanced Cx43 expression and gap junctional intercellular communication in MC3T3-E1 cells. GLP-1R antagonist pretreatment abrogated the induction of Cx43 expression. Cx43 silencing significantly decreased ARS staining intensity in Ex-4-treated cells, whereas overexpression enhanced cell differentiation. Treatment with KX2-391 reduced both the Ex-4-induced increase of Cx43 expression and p-Akt protein levels. sc79 upregulated Cx43 expression, while LY294002 attenuated Cx43 upregulation by Ex-4. CONCLUSIONS Induced Cx43 expression in osteoblasts via the Src-Akt signaling pathway illustrates the underlying mechanism for promoting osteoblast differentiation by Ex-4.
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Affiliation(s)
- Jin Hong Chen
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jeonbuk National University Medical School, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea
| | - Chen Shen
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jeonbuk National University Medical School, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea
| | - Haram Oh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jeonbuk National University Medical School, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea
| | - Ji Hyun Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jeonbuk National University Medical School, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea.
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20
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Liu J, Chen C, Liu Z, Luo Z, Rao S, Jin L, Wan T, Yue T, Tan Y, Yin H, Yang F, Huang F, Guo J, Wang Y, Xia K, Cao J, Wang Z, Hong C, Luo M, Hu X, Liu Y, Du W, Luo J, Hu Y, Zhang Y, Huang J, Li H, Wu B, Liu H, Chen T, Qian Y, Li Y, Feng S, Chen Y, Qi L, Xu R, Tang S, Xie H. Extracellular Vesicles from Child Gut Microbiota Enter into Bone to Preserve Bone Mass and Strength. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2004831. [PMID: 33977075 PMCID: PMC8097336 DOI: 10.1002/advs.202004831] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Indexed: 05/02/2023]
Abstract
Recently, the gut microbiota (GM) has been shown to be a regulator of bone homeostasis and the mechanisms by which GM modulates bone mass are still being investigated. Here, it is found that colonization with GM from children (CGM) but not from the elderly (EGM) prevents decreases in bone mass and bone strength in conventionally raised, ovariectomy (OVX)-induced osteoporotic mice. 16S rRNA gene sequencing reveals that CGM reverses the OVX-induced reduction of Akkermansia muciniphila (Akk). Direct replenishment of Akk is sufficient to correct the OVX-induced imbalanced bone metabolism and protect against osteoporosis. Mechanistic studies show that the secretion of extracellular vesicles (EVs) is required for the CGM- and Akk-induced bone protective effects and these nanovesicles can enter and accumulate into bone tissues to attenuate the OVX-induced osteoporotic phenotypes by augmenting osteogenic activity and inhibiting osteoclast formation. The study identifies that gut bacterium Akk mediates the CGM-induced anti-osteoporotic effects and presents a novel mechanism underlying the exchange of signals between GM and host bone.
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21
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Yang Y, Liu W, Wei J, Cui Y, Zhang D, Xie J. Transforming growth factor-β1-induced N-cadherin drives cell-cell communication through connexin43 in osteoblast lineage. Int J Oral Sci 2021; 13:15. [PMID: 33850101 PMCID: PMC8044142 DOI: 10.1038/s41368-021-00119-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/29/2020] [Accepted: 02/01/2021] [Indexed: 02/05/2023] Open
Abstract
Gap junction (GJ) has been indicated to have an intimate correlation with adhesion junction. However, the direct interaction between them partially remains elusive. In the current study, we aimed to elucidate the role of N-cadherin, one of the core components in adhesion junction, in mediating connexin 43, one of the functional constituents in gap junction, via transforming growth factor-β1(TGF-β1) induction in osteoblasts. We first elucidated the expressions of N-cadherin induced by TGF-β1 and also confirmed the upregulation of Cx43, and the enhancement of functional gap junctional intercellular communication (GJIC) triggered by TGF-β1 in both primary osteoblasts and MC3T3 cell line. Colocalization analysis and Co-IP experimentation showed that N-cadherin interacts with Cx43 at the site of cell-cell contact. Knockdown of N-cadherin by siRNA interference decreased the Cx43 expression and abolished the promoting effect of TGF-β1 on Cx43. Functional GJICs in living primary osteoblasts and MC3T3 cell line were also reduced. TGF-β1-induced increase in N-cadherin and Cx43 was via Smad3 activation, whereas knockdown of Smad3 signaling by using siRNA decreased the expressions of both N-cadherin and Cx43. Overall, these data indicate the direct interactions between N-cadherin and Cx43, and reveal the intervention of adhesion junction in functional gap junction in living osteoblasts.
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Affiliation(s)
- Yueyi Yang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Wenjing Liu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - JieYa Wei
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yujia Cui
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Demao Zhang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management & West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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22
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Li Z, Gu S, Quan Y, Varadaraj K, Jiang JX. Development of a potent embryonic chick lens model for studying congenital cataracts in vivo. Commun Biol 2021; 4:325. [PMID: 33707565 PMCID: PMC7952907 DOI: 10.1038/s42003-021-01849-0] [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: 09/03/2020] [Accepted: 02/11/2021] [Indexed: 01/31/2023] Open
Abstract
Congenital cataracts are associated with gene mutations, yet the underlying mechanism remains largely unknown. Here we reported an embryonic chick lens model that closely recapitulates the process of cataract formation. We adopted dominant-negative site mutations that cause congenital cataracts, connexin, Cx50E48K, aquaporin 0, AQP0R33C, αA-crystallin, CRYAA R12C and R54C. The recombinant retroviruses containing these mutants were microinjected into the occlusive lumen of chick lenses at early embryonic development. Cx50E48K expression developed cataracts associated with disorganized nuclei and enlarged extracellular spaces. Expression of AQP0R33C resulted in cortical cataracts, enlarged extracellular spaces and distorted fiber cell organization. αA crystallin mutations distorted lens light transmission and increased crystalline protein aggregation. Together, retroviral expression of congenital mutant genes in embryonic chick lenses closely mimics characteristics of human congenital cataracts. This model will provide an effective, reliable in vivo system to investigate the development and underlying mechanism of cataracts and other genetic diseases.
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Affiliation(s)
- Zhen Li
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Sumin Gu
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Yumeng Quan
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Kulandaiappan Varadaraj
- grid.36425.360000 0001 2216 9681Department of Physiology and Biophysics, Stony Brook University, New York, NY USA
| | - Jean X. Jiang
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
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Intercellular mitochondrial transfer as a means of tissue revitalization. Signal Transduct Target Ther 2021; 6:65. [PMID: 33589598 PMCID: PMC7884415 DOI: 10.1038/s41392-020-00440-z] [Citation(s) in RCA: 126] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 11/04/2020] [Accepted: 11/24/2020] [Indexed: 01/31/2023] Open
Abstract
As the crucial powerhouse for cell metabolism and tissue survival, the mitochondrion frequently undergoes morphological or positional changes when responding to various stresses and energy demands. In addition to intracellular changes, mitochondria can also be transferred intercellularly. Besides restoring stressed cells and damaged tissues due to mitochondrial dysfunction, the intercellular mitochondrial transfer also occurs under physiological conditions. In this review, the phenomenon of mitochondrial transfer is described according to its function under both physiological and pathological conditions, including tissue homeostasis, damaged tissue repair, tumor progression, and immunoregulation. Then, the mechanisms that contribute to this process are summarized, such as the trigger factors and transfer routes. Furthermore, various perspectives are explored to better understand the mysteries of cell-cell mitochondrial trafficking. In addition, potential therapeutic strategies for mitochondria-targeted application to rescue tissue damage and degeneration, as well as the inhibition of tumor progression, are discussed.
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24
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Hua R, Zhang J, Riquelme MA, Jiang JX. Connexin Gap Junctions and Hemichannels Link Oxidative Stress to Skeletal Physiology and Pathology. Curr Osteoporos Rep 2021; 19:66-74. [PMID: 33403446 PMCID: PMC8174533 DOI: 10.1007/s11914-020-00645-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/16/2020] [Indexed: 12/15/2022]
Abstract
PURPOSE OF REVIEW The goal of this review is to provide an overview of the impact and underlying mechanism of oxidative stress on connexin channel function, and their roles in skeletal aging, estrogen deficiency, and glucocorticoid excess associated bone loss. RECENT FINDINGS Connexin hemichannel opening is increased under oxidative stress conditions, which confers a cell protective role against oxidative stress-induced cell death. Oxidative stress acts as a key contributor to aging, estrogen deficiency, and glucocorticoid excess-induced osteoporosis and impairs osteocytic network and connexin gap junction communication. This paper reviews the current knowledge for the role of oxidative stress and connexin channels in the pathogenesis of osteoporosis and physiological and pathological responses of connexin channels to oxidative stress. Oxidative stress decreases osteocyte viability and impairs the balance of anabolic and catabolic responses. Connexin 43 (Cx43) channels play a critical role in bone remodeling, mechanotransduction, and survival of osteocytes. Under oxidative stress conditions, there is a consistent reduction of Cx43 expression, while the opening of Cx43 hemichannels protects osteocytes against cell injury caused by oxidative stress.
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Affiliation(s)
- Rui Hua
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Jingruo Zhang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Manuel A Riquelme
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA.
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25
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Yin J, Xu J, Cheng R, Shao M, Qin Y, Yang H, Hu T. Role of connexin 43 in odontoblastic differentiation and structural maintenance in pulp damage repair. Int J Oral Sci 2021; 13:1. [PMID: 33414369 PMCID: PMC7791050 DOI: 10.1038/s41368-020-00105-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 10/31/2020] [Accepted: 12/02/2020] [Indexed: 02/05/2023] Open
Abstract
Dental pulp can initiate its damage repair after an injury of the pulp–dentin complex by rearrangement of odontoblasts and formation of newly differentiated odontoblast-like cells. Connexin 43 (Cx43) is one of the gap junction proteins that participates in multiple tissue repair processes. However, the role of Cx43 in the repair of the dental pulp remains unclear. This study aimed to determine the function of Cx43 in the odontoblast arrangement patterns and odontoblastic differentiation. Human teeth for in vitro experiments were acquired, and a pulp injury model in Sprague-Dawley rats was used for in vivo analysis. The odontoblast arrangement pattern and the expression of Cx43 and dentin sialophosphoprotein (DSPP) were assessed. To investigate the function of Cx43 in odontoblastic differentiation, we overexpressed or inhibited Cx43. The results indicated that polarized odontoblasts were arranged along the pulp–dentin interface and had high levels of Cx43 expression in the healthy teeth; however, the odontoblast arrangement pattern was slightly changed concomitant to an increase in the Cx43 expression in the carious teeth. Regularly arranged odontoblast-like cells had high levels of the Cx43 expression during the formation of mature dentin, but the odontoblast-like cells were not regularly arranged beneath immature osteodentin in the pulp injury models. Subsequent in vitro experiments demonstrated that Cx43 is upregulated during odontoblastic differentiation of the dental pulp cells, and inhibition or overexpression of Cx43 influence the odontoblastic differentiation. Thus, Cx43 may be involved in the maintenance of odontoblast arrangement patterns, and influence the pulp repair outcomes by the regulation of odontoblastic differentiation.
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Affiliation(s)
- Jiaxin Yin
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Endodontics, School of Stomatology, Capital Medical University, Beijing, China
| | - Jue Xu
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Ran Cheng
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Meiying Shao
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Yuandong Qin
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hui Yang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China.
| | - Tao Hu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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26
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Hua R, Ni Q, Eliason TD, Han Y, Gu S, Nicolella DP, Wang X, Jiang JX. Biglycan and chondroitin sulfate play pivotal roles in bone toughness via retaining bound water in bone mineral matrix. Matrix Biol 2020; 94:95-109. [PMID: 33002580 DOI: 10.1016/j.matbio.2020.09.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/23/2020] [Accepted: 09/23/2020] [Indexed: 12/22/2022]
Abstract
Recent in vitro evidence shows that glycosaminoglycans (GAGs) and proteoglycans (PGs) in bone matrix may functionally be involved in the tissue-level toughness of bone. In this study, we showed the effect of biglycan (Bgn), a small leucine-rich proteoglycan enriched in extracellular matrix of bone and the associated GAG subtype, chondroitin sulfate (CS), on the toughness of bone in vivo, using wild-type (WT) and Bgn deficient mice. The amount of total GAGs and CS in the mineralized compartment of Bgn KO mouse bone matrix decreased significantly, associated with the reduction of the toughness of bone, in comparison with those of WT mice. However, such differences between WT and Bgn KO mice diminished once the bound water was removed from bone matrix. In addition, CS was identified as the major subtype in bone matrix. We then supplemented CS to both WT and Bgn KO mice to test whether supplemental GAGs could improve the tissue-level toughness of bone. After intradermal administration of CS, the toughness of WT bone was greatly improved, with the GAGs and bound water amount in the bone matrix increased, while such improvement was not observed in Bgn KO mice or with supplementation of dermatan sulfate (DS). Moreover, CS supplemented WT mice exhibited higher bone mineral density and reduced osteoclastogenesis. Interestingly, Bgn KO bone did not show such differences irrespective of the intradermal administration of CS. In summary, the results of this study suggest that Bgn and CS in bone matrix play a pivotal role in imparting the toughness to bone most likely via retaining bound water in bone matrix. Moreover, supplementation of CS improves the toughness of bone in mouse models.
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Affiliation(s)
- Rui Hua
- Department of Biochemistry and Structural Biology, UT Health, San Antonio, TX, USA
| | - Qingwen Ni
- Department of Physics, Texas A&M International University, Laredo, TX, USA
| | - Travis D Eliason
- Department of Materials Engineering, Southwest Research Institute, San Antonio, TX, USA
| | - Yan Han
- Department of Mechanical Engineering, University of Texas at San Antonio, TX, USA
| | - Sumin Gu
- Department of Biochemistry and Structural Biology, UT Health, San Antonio, TX, USA
| | - Daniel P Nicolella
- Department of Materials Engineering, Southwest Research Institute, San Antonio, TX, USA
| | - Xiaodu Wang
- Department of Mechanical Engineering, University of Texas at San Antonio, TX, USA.
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, UT Health, San Antonio, TX, USA.
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Qin L, Liu W, Cao H, Xiao G. Molecular mechanosensors in osteocytes. Bone Res 2020; 8:23. [PMID: 32550039 PMCID: PMC7280204 DOI: 10.1038/s41413-020-0099-y] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/07/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022] Open
Abstract
Osteocytes, the most abundant and long-lived cells in bone, are the master regulators of bone remodeling. In addition to their functions in endocrine regulation and calcium and phosphate metabolism, osteocytes are the major responsive cells in force adaptation due to mechanical stimulation. Mechanically induced bone formation and adaptation, disuse-induced bone loss and skeletal fragility are mediated by osteocytes, which sense local mechanical cues and respond to these cues in both direct and indirect ways. The mechanotransduction process in osteocytes is a complex but exquisite regulatory process between cells and their environment, between neighboring cells, and between different functional mechanosensors in individual cells. Over the past two decades, great efforts have focused on finding various mechanosensors in osteocytes that transmit extracellular mechanical signals into osteocytes and regulate responsive gene expression. The osteocyte cytoskeleton, dendritic processes, Integrin-based focal adhesions, connexin-based intercellular junctions, primary cilium, ion channels, and extracellular matrix are the major mechanosensors in osteocytes reported so far with evidence from both in vitro and in vitro studies. This review aims to give a systematic introduction to osteocyte mechanobiology, provide details of osteocyte mechanosensors, and discuss the roles of osteocyte mechanosensitive signaling pathways in the regulation of bone homeostasis.
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Affiliation(s)
- Lei Qin
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Wen Liu
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Huiling Cao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Guozhi Xiao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
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Zhang D, Li X, Pi C, Cai L, Liu Y, Du W, Yang W, Xie J. Osteoporosis-decreased extracellular matrix stiffness impairs connexin 43-mediated gap junction intercellular communication in osteocytes. Acta Biochim Biophys Sin (Shanghai) 2020; 52:517-526. [PMID: 32286624 DOI: 10.1093/abbs/gmaa025] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/20/2019] [Accepted: 02/24/2020] [Indexed: 02/05/2023] Open
Abstract
Osteocytes are the main sensitive and responsive cells for mechanical stimuli in bone. The connexin family enables them to communicate with each other via forming functional gap junctions. However, how osteoporosis-impaired extracellular mechanical property modulates gap junction intercellular communication in osteocytes remains elusive. In this study, we established an ovariectomy (OVX)-induced osteoporosis mouse model in vivo and a polydimethylsiloxane (PDMS)-based cell culture substrate model in vitro to explore the influence of extracellular matrix (ECM) stiffness on cell-to-cell communication in osteocytes. Firstly, we established an OVX-induced osteoporosis mouse model by characterizing the changes in radiography, morphology and histochemistry of femurs. Our results showed that osteoporosis decreased the bone matrix stiffness together with the changes including the loss of osteocytes and the decrease of protein markers. Meanwhile, the dendritic process interconnection and channel-forming protein, Cx43, were reduced in osteoporosis mice. Next we mimicked ECM stiffness changes in vitro by using PDMS substrates at ratios 1:5 for normal stiffness and 1:45 for osteoporosis stiffness. Our results showed that the decreased ECM stiffness reduced the number of dendritic processes in a single cell and gap junctions between adjacent osteocytes. We further detected the decreased expression of Cx43, in the substrate with decreased stiffness. Finally, we found that gap junction-based intercellular communication was reduced in living osteocytes in the substrate with decreased stiffness. This study demonstrates the correlation between ECM mechanical property and cell-to-cell communication in osteocytes and might pave the way for further exploration of osteoporosis in terms of biomechanics.
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Affiliation(s)
- Demao Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Xin Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Caixia Pi
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Linyi Cai
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Yang Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Wei Du
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Wenbin Yang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
- National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
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Abstract
Bone is the most frequent site of breast cancer and prostate cancer metastasis, and one of the most common sites of metastasis for many solid tumors. Once cancer cells colonize in the bone, it imposes a major clinical challenge for the treatment of the disease, and fatality rates increase drastically. Bone, the largest organ in the body, provides a fertile microenvironment enriched with nutrients, growth factors and hormones, a generous reward for cancer cells. Dependent on cancer type, cancer cells can cause osteoblastic (bone forming) or osteolytic lesions to promote the net resorption and/or release of growth factors from the bone extracellular matrix. These processes activate a "vicious cycle", leading to disruption of bone integrity and promoting cancer cell growth and migration. Cancer cells influence the bone microenvironment favoring their colonization and growth. In order to metastasize to the bone, cancer cells must first migrate from the site of origin, and once established within the bone, they must overcome the dormant inducing effects of resident cells. If successful, cancer cells can then colonize and continually disrupt bone homeostasis that is primarily maintained by osteocytes, the most abundant bone cell type. For example, it has been shown that exercise induces osteocytes to release anabolic factors that inhibit osteoclast resorptive activity, promote dormancy and the release of anti-cancer factors that inhibit breast cancer cell metastasis. In this review, we will summarize recent research findings and provide mechanistic insights related to the role of osteocytes in osteolytic metastasis.
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