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Endocrine Reviews May 2023Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and...
Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and interpretation of these markers, which include commonly used bone formation markers (bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide); and commonly used resorption markers (serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen, and tartrate-resistant acid phosphatase type 5b). BTMs are usually measured by enzyme-linked immunosorbent assay or automated immunoassay. Sources contributing to BTM variability include uncontrollable factors (eg, age, gender, ethnicity) and controllable factors, particularly relating to collection conditions (eg, fasting/feeding state, and timing relative to circadian rhythms, menstrual cycling, and exercise). Pregnancy, season, drugs, and recent fracture(s) can also affect BTMs. BTMs correlate with other methods of assessing bone turnover, such as bone biopsies and radiotracer kinetics, and can usefully contribute to diagnosis and management of several diseases such as osteoporosis, osteomalacia, Paget's disease, fibrous dysplasia, hypophosphatasia, primary hyperparathyroidism, and chronic kidney disease-mineral bone disorder.
Topics: Humans; Collagen Type I; Acid Phosphatase; Alkaline Phosphatase; Bone Remodeling; Biology; Bone Resorption
PubMed: 36510335
DOI: 10.1210/endrev/bnac031 -
Tartrate-resistant acid phosphatase 5 promotes pulmonary fibrosis by modulating β-catenin signaling.Nature Communications Jan 2022Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease with limited therapeutic options. Tartrate-resistant acid phosphatase 5 (ACP5) performs a...
Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease with limited therapeutic options. Tartrate-resistant acid phosphatase 5 (ACP5) performs a variety of functions. However, its role in IPF remains unclear. Here, we demonstrate that the levels of ACP5 are increased in IPF patient samples and mice with bleomycin (BLM)-induced pulmonary fibrosis. In particular, higher levels of ACP5 are present in the sera of IPF patients with a diffusing capacity of the lungs for carbonmonoxide (DLCO) less than 40% of the predicted value. Additionally, Acp5 deficiency protects mice from BLM-induced lung injury and fibrosis coupled with a significant reduction of fibroblast differentiation and proliferation. Mechanistic studies reveal that Acp5 is upregulated by transforming growth factor-β1 (TGF-β1) in a TGF-β receptor 1 (TGFβR1)/Smad family member 3 (Smad3)-dependent manner, after which Acp5 dephosphorylates p-β-catenin at serine 33 and threonine 41, inhibiting the degradation of β-catenin and subsequently enhancing β-catenin signaling in the nucleus, which promotes the differentiation, proliferation and migration of fibroblast. More importantly, the treatment of mice with Acp5 siRNA-loaded liposomes or Acp5 inhibitor reverses established lung fibrosis. In conclusions, Acp5 is involved in the initiation and progression of pulmonary fibrosis and strategies aimed at silencing or suppressing Acp5 could be considered as potential therapeutic approaches against pulmonary fibrosis.
Topics: Animals; Bleomycin; Carbon Monoxide; Cell Differentiation; Cell Movement; Cell Proliferation; Disease Models, Animal; Fibroblasts; Gene Expression Regulation; Humans; Lung; Male; Mice; Phosphorylation; Pulmonary Fibrosis; RNA, Small Interfering; Respiratory Function Tests; Signal Transduction; Smad3 Protein; Tartrate-Resistant Acid Phosphatase; Transforming Growth Factor beta1; beta Catenin
PubMed: 35013220
DOI: 10.1038/s41467-021-27684-9 -
Cell Proliferation Oct 2022The main target of current drugs for alleviating bone loss is osteoclasts. However, the long-term application of such drugs will also cause side effects. Therefore, it...
OBJECTIVES
The main target of current drugs for alleviating bone loss is osteoclasts. However, the long-term application of such drugs will also cause side effects. Therefore, it is of great need to develop new and safer therapeutics for osteoporosis. In recent years, drug development based on gut microbiota has gradually attracted attention. This manuscript investigates the inhibitory effect of urolithin B (UB) on osteoclastogenesis and differentiation in vitro and in ovariectomized (OVX) mice.
MATERIALS AND METHODS
CCK-8 was used to analyse the cytotoxicity of UB; BMMs cells were differentiated into osteoclasts by RANKL, and respectively treated with 1, 5, and 25 μmol/L UB during this process. After one week of intervention, tartrate-resistant acid phosphatase (TRAP) staining was used to analyse the number and average area of osteoclasts. F-actin staining and immunofluorescence staining were conducted to evaluate the morphology and function of osteoclasts. Bone resorption function of osteoclasts was detected by Pit Formation Assay. The expression of osteoclast-related protein genes in RAW264.7 cells were investigated via western blot and RT-PCR assays. Western blot analysis of RANKL-mediated activation of MAPK/NF-κB pathway after 0, 5, 15, 30, 60 min of intervention. For in vivo experiments, OVX mice received intraperitoneal injection of 10, 50 mg/kg every two days, 8 weeks later, the femurs of mice were taken for morphological analysis, and the serum content of CTX-1, a bone metabolism index, was analysed.
RESULTS
UB could inhibit the osteoclast differentiation of rankl-induced bone marrow macrophages (BMMs) and RAW264.7 cells in vitro, suppress the uptake activity of hydroxyapatite and expression of osteoclast-related gene MMP9, CTSK, NFATc1 and c-fos. Furthermore, UB repressed the rankl-induced phosphorylation and degradation of IκB and the phosphorylation of P65 in the NF-κB pathway of RAW264.7 cells, and also down-regulated the phosphorylation level of ERK in the MAPK pathway. For in vivo studies, UB-treated OVX mice showed more significant improved various parameters of distal femur compared with the control group, with fewer NFATc1, MMP9 and TRAP-positive osteoclasts in bone tissues, and less serum content of CTX-1.
CONCLUSION
Urolithin B attenuated bone loss in OVX mice by inhibiting the formation and activation of osteoclasts via down-regulation of the ERK/NF-κB signalling pathway.
Topics: Actins; Animals; Cell Differentiation; Coumarins; Hydroxyapatites; Matrix Metalloproteinase 9; Mice; NF-kappa B; NFATC Transcription Factors; Osteoclasts; Osteogenesis; Osteoporosis; RANK Ligand; Sincalide; Tartrate-Resistant Acid Phosphatase
PubMed: 35708050
DOI: 10.1111/cpr.13291 -
Nature Apr 2022Human telomerase is a RNA-protein complex that extends the 3' end of linear chromosomes by synthesizing multiple copies of the telomeric repeat TTAGGG. Its activity is a...
Human telomerase is a RNA-protein complex that extends the 3' end of linear chromosomes by synthesizing multiple copies of the telomeric repeat TTAGGG. Its activity is a determinant of cancer progression, stem cell renewal and cellular aging. Telomerase is recruited to telomeres and activated for telomere repeat synthesis by the telomere shelterin protein TPP1. Human telomerase has a bilobal structure with a catalytic core ribonuclear protein and a H and ACA box ribonuclear protein. Here we report cryo-electron microscopy structures of human telomerase catalytic core of telomerase reverse transcriptase (TERT) and telomerase RNA (TER (also known as hTR)), and of telomerase with the shelterin protein TPP1. TPP1 forms a structured interface with the TERT-unique telomerase essential N-terminal domain (TEN) and the telomerase RAP motif (TRAP) that are unique to TERT, and conformational dynamics of TEN-TRAP are damped upon TPP1 binding, defining the requirements for recruitment and activation. The structures further reveal that the elements of TERT and TER that are involved in template and telomeric DNA handling-including the TEN domain and the TRAP-thumb helix channel-are largely structurally homologous to those in Tetrahymena telomerase, and provide unique insights into the mechanism of telomerase activity. The binding site of the telomerase inhibitor BIBR1532 overlaps a critical interaction between the TER pseudoknot and the TERT thumb domain. Numerous mutations leading to telomeropathies are located at the TERT-TER and TEN-TRAP-TPP1 interfaces, highlighting the importance of TER-TERT and TPP1 interactions for telomerase activity, recruitment and as drug targets.
Topics: Binding Sites; Cryoelectron Microscopy; Humans; Protein Binding; Shelterin Complex; Tartrate-Resistant Acid Phosphatase; Telomerase; Telomere; Telomere-Binding Proteins
PubMed: 35418675
DOI: 10.1038/s41586-022-04582-8 -
Journal of Orthopaedic Translation Nov 2022Osteoporosis (OP) is a systemic metabolic bone disease characterized by decreased bone mass and destruction of bone microstructure, which tends to result in enhanced...
BACKGROUND
Osteoporosis (OP) is a systemic metabolic bone disease characterized by decreased bone mass and destruction of bone microstructure, which tends to result in enhanced bone fragility and related fractures. The postmenopausal osteoporosis (PMOP) has a relatively high proportion, and numerous studies reveal that estrogen-deficiency is related to the imbalance of gut microbiota (GM), impaired intestinal mucosal barrier function and enhanced inflammatory reactivity. However, the underlying mechanisms remain unclear and the existing interventions are also scarce.
METHODS
In this study, we established a mouse model induced by ovariectomy (OVX) and conducted fecal microbiota transplantation (FMT) by gavage every day for 8 weeks. Subsequently, the bone mass and microarchitecture of mice were evaluated by the micro computed tomography (Micro-CT). The intestinal permeability, pro-osteoclastogenic cytokines expression, osteogenic and osteoclastic activities were detected by the immunohistological analysis, histological examination, enzyme-linked immunosorbent assay (ELISA) and western blot analysis accordingly. Additionally, the composition and abundance of GM were assessed by 16S rRNA sequencing and the fecal short chain fatty acids (SCFAs) level was measured by metabolomics.
RESULTS
Our results demonstrated that FMT inhibited the excessive osteoclastogenesis and prevented the OVX-induced bone loss. Specifically, compared with the OVX group, FMT enhanced the expressions of tight junction proteins (zonula occludens protein 1 (ZO-1) and Occludin) and suppressed the release of pro-osteoclastogenic cytokines (tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β)). Furthermore, FMT also optimized the composition and abundance of GM, and increased the fecal SCFAs level (mainly acetic acid and propionic acid).
CONCLUSIONS
Collectively, based on GM-bone axis, FMT prevented the OVX-induced bone loss by correcting the imbalance of GM, improving the SCFAs level, optimizing the intestinal permeability and suppressing the release of pro-osteoclastogenic cytokines, which may be an alternative option to serve as a promising candidate for the prevention and treatment of PMOP in the future.
THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE
This study indicates the ingenious involvement of GM-bone axis in PMOP and the role of FMT in reshaping the status of GM and ameliorating the bone loss in OVX-induced mice. FMT might serve as a promising candidate for the prevention and treatment of PMOP in the future.
PubMed: 36196151
DOI: 10.1016/j.jot.2022.08.003 -
Biochemistry and Biophysics Reports Jul 2021Serpinb1a, a serine protease inhibitor family protein, has been implicated in immunoregulation and several metabolic disorders, such as diabetes and obesity; however,...
Serpinb1a, a serine protease inhibitor family protein, has been implicated in immunoregulation and several metabolic disorders, such as diabetes and obesity; however, its roles in bone remain unknown. Therefore, we herein investigated the physiological functions of Serpinb1a in osteoclastic and osteoblastic differentiation using mouse cell lines. Serpinb1a overexpression markedly reduced the number of tartrate-resistant acid phosphatase (TRAP)- and calcitonin receptor-positive multinucleated cells increased by receptor activator nuclear factor κB ligand (RANKL) in mouse preosteoclastic RAW 264.7 cells. Moreover, it significantly decreased the mRNA levels of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), TRAP and cathepsin K in these cells. Regarding osteoblasts, Serpinb1a overexpression significantly reduced the mRNA levels of alkaline phosphatase (ALP) and osteocalcin as well as ALP activity induced by bone morphogenetic protein-2 (BMP-2) in mouse mesenchymal ST2 cells, although it did not alter osteoblast differentiation in mouse osteoblastic MC3T3-E1 cells. Concerning the pathophysiological relevance of Serpinb1a, Serpinb1a mRNA levels were decreased in the soleus and gastrocnemius muscles of mice 4 weeks after bilateral sciatic nerve resection. In conclusion, we herein revealed for the first time that Serpinb1a inhibited osteoclast formation induced by RANKL in RAW 264.7 cells and suppressed BMP-2-induced ALP activity in ST2 cells.
PubMed: 33997318
DOI: 10.1016/j.bbrep.2021.101004 -
Bioactive Materials Mar 2023The disability, mortality and costs due to ionizing radiation (IR)-induced osteoporotic bone fractures are substantial and no effective therapy exists. Ionizing...
The disability, mortality and costs due to ionizing radiation (IR)-induced osteoporotic bone fractures are substantial and no effective therapy exists. Ionizing radiation increases cellular oxidative damage, causing an imbalance in bone turnover that is primarily driven heightened activity of the bone-resorbing osteoclast. We demonstrate that rats exposed to sublethal levels of IR develop fragile, osteoporotic bone. At reactive surface sites, cerium ions have the ability to easily undergo redox cycling: drastically adjusting their electronic configurations and versatile catalytic activities. These properties make cerium oxide nanomaterials fascinating. We show that an engineered artificial nanozyme composed of cerium oxide, and designed to possess a higher fraction of trivalent (Ce) surface sites, mitigates the IR-induced loss in bone area, bone architecture, and strength. These investigations also demonstrate that our nanozyme furnishes several mechanistic avenues of protection and selectively targets highly damaging reactive oxygen species, protecting the rats against IR-induced DNA damage, cellular senescence, and elevated osteoclastic activity and . Further, we reveal that our nanozyme is a previously unreported key regulator of osteoclast formation derived from macrophages while also directly targeting bone progenitor cells, favoring new bone formation despite its exposure to harmful levels of IR . These findings open a new approach for the specific prevention of IR-induced bone loss using synthesis-mediated designer multifunctional nanomaterials.
PubMed: 36185749
DOI: 10.1016/j.bioactmat.2022.09.011 -
Comparative Medicine Aug 2021() encodes a small neutral amino-acid exchanger and is the most well-studied glutamine transporter in cancer cells. To investigate the role of in osteoclastogenesis,...
() encodes a small neutral amino-acid exchanger and is the most well-studied glutamine transporter in cancer cells. To investigate the role of in osteoclastogenesis, we developed -deficient mice by using a conventional gene-targeting approach. The 5 mice showed no obvious abnormalities in growth. Glutamine uptake was assessed in and bone marrow cells stimulated with RANKL. The rate of glutamine uptake in bone marrow cells was reduced to 70% of that of cells from bone marrow. To confirm the involvement of in osteoclast formation, bone marrow cells derived from or mice were stimulated with RANKL and macrophage colony-stimulating factor and stained with tartrate-resistant acid phosphatase. The bone resorption activity and actin ring formation of stimulated cells were measured. The formation of multinucleated osteoclasts in bone marrow cells isolated from mice was severely impaired compared with those from mice. RANKL-induced expression of ERK, NFκB, p70S6K, and NFATc1 was suppressed in osteoclasts. These results show that plays an important role in osteoclast formation.
Topics: Amino Acid Transport System ASC; Animals; Bone Marrow Cells; Bone Resorption; Cell Differentiation; Mice; Minor Histocompatibility Antigens; Osteoclasts; Osteogenesis; Tartrate-Resistant Acid Phosphatase
PubMed: 34301346
DOI: 10.30802/AALAS-CM-21-000012 -
Cancer Letters Nov 2021The effects of bone metastatic cancer on the skeleton are well described, whereas less is known regarding the effects of non-metastatic bone cancer on bone. Here we...
The effects of bone metastatic cancer on the skeleton are well described, whereas less is known regarding the effects of non-metastatic bone cancer on bone. Here we investigated the effects of three non-bone metastatic cancer cachexia models, namely Colon-26 adenocarcinoma (C26), ES-2 ovarian cancer (ES-2), and Lewis lung carcinoma (LLC). Even though C26, ES-2 and LLC tumor growth resulted in comparable weight and muscle loss, the ES-2 and LLC hosts exhibited severe bone loss, whereas only modest bone loss was observed in the C26 bearers, correlating with increased TRAP osteoclasts in the femurs of ES-2 and LLC but not C26 hosts. Surprisingly, all three showed increased osteocyte lacunar area indicating osteocytic osteolysis and displayed dramatically increased osteocyte death, as well as empty lacunae. To test whether tumor-secreted factors were responsible for the observed effect, IDG-SW3 osteocyte cells were co-cultured with cancer cells in permeable trans-wells. Apoptosis was observed in the osteocyte cells exposed to all three cancer cell lines suggesting that all tumors were cytotoxic for osteocytes. In addition, the expression of the osteoclastic markers, Acp5, CtsK, Atp6v0d2 and Mmp13, was elevated in IDG-SW3 osteocytes exposed to tumor factors, supporting the in vivo observations of increased lacunar size due to osteocytic osteolysis. For the first time, we describe osteocytic bone destruction and extensive osteocyte cell death in non-bone metastatic cancer. These bone alterations, in conjunction with muscle wasting, may create a musculoskeletal system that is incapable of full recovery upon eradication of tumor. Co-treatment with bone preserving therapies should be considered.
Topics: Animals; Apoptosis; Bone Neoplasms; Bone and Bones; Carcinoma, Lewis Lung; Cathepsin K; Colonic Neoplasms; Female; Gene Expression Regulation, Neoplastic; Humans; Matrix Metalloproteinase 13; Mice; Neoplasm Metastasis; Osteoclasts; Osteocytes; Osteolysis; Ovarian Neoplasms; Tartrate-Resistant Acid Phosphatase; Vacuolar Proton-Translocating ATPases
PubMed: 34233150
DOI: 10.1016/j.canlet.2021.06.030