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International Journal of Molecular... Aug 2024The ubiquitin (Ub)‑proteasome system (UPS) plays a pivotal role in maintaining protein homeostasis and function to modulate various cellular processes including... (Review)
Review
The ubiquitin (Ub)‑proteasome system (UPS) plays a pivotal role in maintaining protein homeostasis and function to modulate various cellular processes including skeletal cell differentiation and bone homeostasis. The Ub ligase E3 promotes the transfer of Ub to the target protein, especially transcription factors, to regulate the proliferation, differentiation and survival of bone cells, as well as bone formation. In turn, the deubiquitinating enzyme removes Ub from modified substrate proteins to orchestrate bone remodeling. As a result of abnormal regulation of ubiquitination, bone cell differentiation exhibits disorder and then bone homeostasis is affected, consequently leading to osteoporosis. The present review discussed the role and mechanism of UPS in bone remodeling. However, the specific mechanism of UPS in the process of bone remodeling is still not fully understood and further research is required. The study of the mechanism of action of UPS can provide new ideas and methods for the prevention and treatment of osteoporosis. In addition, the most commonly used osteoporosis drugs that target ubiquitination processes in the clinic are discussed in the current review.
Topics: Humans; Osteoporosis; Ubiquitination; Animals; Ubiquitin; Proteasome Endopeptidase Complex; Bone Remodeling; Ubiquitin-Protein Ligases
PubMed: 38940355
DOI: 10.3892/ijmm.2024.5392 -
Frontiers in Pharmacology 2024Although caffeine generally offers benefits to human health, its impact on bone metabolism remains unclear. This study aimed to systematically evaluate the long-term...
Although caffeine generally offers benefits to human health, its impact on bone metabolism remains unclear. This study aimed to systematically evaluate the long-term effects of caffeine administration on osteoclasts, osteoblasts, and ovariectomy-induced postmenopausal osteoporosis (OP). Our findings revealed that 3.125 and 12.5 μg/mL caffeine inhibited RANKL-mediated osteoclastogenesis in RAW 264.7 cells through the MAPK and NF-κB pathways, accompanied by the inactivation of nuclear translocation of nuclear factor NFATc1. Similarly, 3.125 and 12.5 μg/mL of caffeine modulated MC3T3-E1 osteogenesis via the AKT, MAPK, and NF-κB pathways. However, 50 μg/mL of caffeine promoted the phosphorylation of IκBα, P65, JNK, P38, and AKT, followed by the activation of NFATc1 and the inactivation of Runx2 and Osterix, ultimately disrupting the balance between osteoblastogenesis and osteoclastogenesis. studies showed that gavage with 55.44 mg/kg caffeine inhibited osteoclastogenesis, promoted osteogenesis, and ameliorated bone loss in ovariectomized mice. Conversely, long-term intake of high-dose caffeine (110.88 mg/kg) disrupted osteogenesis activity and promoted osteoclastogenesis, thereby disturbing bone homeostasis. Collectively, these findings suggest that a moderate caffeine intake (approximately 400 mg in humans) can regulate bone homeostasis by influencing both osteoclasts and osteoblasts. However, long-term high-dose caffeine consumption (approximately 800 mg in humans) could have detrimental effects on the skeletal system.
PubMed: 38939843
DOI: 10.3389/fphar.2024.1405173 -
Journal of Periodontology Jun 2024Diabetes is one of the major inflammatory comorbidities of periodontitis via 2-way interactions. Cystathionine γ-lyase (CTH) is a pivotal endogenous enzyme synthesizing...
BACKGROUND
Diabetes is one of the major inflammatory comorbidities of periodontitis via 2-way interactions. Cystathionine γ-lyase (CTH) is a pivotal endogenous enzyme synthesizing hydrogen sulfide (HS), and CTH/HS is crucially implicated in modulating inflammation in various diseases. This study aimed to explore the potential role of CTH in experimental periodontitis under a hyperglycemic condition.
METHODS
CTH-silenced and normal human periodontal ligament cells (hPDLCs) were cultured in a high glucose and Porphyromonas gingivalis lipopolysaccharide (P.g-LPS) condition. The effects of CTH on hPDLCs were assessed by Cell Counting Kit 8 (CCK8), real-time quantitative polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA). The model of experimental periodontitis under hyperglycemia was established on both Cth and wild-type (WT) mice, and the extent of periodontal destruction was assessed by micro-CT, histology, RNA-Seq, Western blot, tartrate-resistant acid phosphatase (TRAP) staining and immunostaining.
RESULTS
CTH mRNA expression increased in hPDLCs in response to increasing concentration of P.g-LPS stimulation in a high glucose medium. With reference to WT mice, Cth mice with experimental periodontitis under hyperglycemia exhibited reduced bone loss, decreased leukocyte infiltration and hindered osteoclast formation, along with reduced expression of proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in periodontal tissue. RNA-seq-enriched altered NF-κB pathway signaling in healthy murine gingiva with experimental periodontitis mice under hyperglycemia. Accordingly, phosphorylation of p65 (P-p65) was alleviated in CTH-silenced hPDLCs, leading to decreased expression of IL6 and TNF. CTH knockdown inhibited activation of nuclear factor kappa-B (NF-κB) pathway and decreased production of proinflammatory cytokines under high glucose and P.g-LPS treatment.
CONCLUSION
The present findings suggest the potential of CTH as a therapeutic target for tackling periodontitis in diabetic patients.
PubMed: 38937859
DOI: 10.1002/JPER.23-0811 -
Biochimica Et Biophysica Acta.... Jun 2024Postmenopausal women experience bone loss and weight gain. To date, crosstalk between estrogen receptor signals and nuclear factor-κB (NF-κB) has been reported, and...
Postmenopausal women experience bone loss and weight gain. To date, crosstalk between estrogen receptor signals and nuclear factor-κB (NF-κB) has been reported, and estrogen depletion enhances bone resorption by osteoclasts via NF-κB activation. However, it is unclear when and in which tissues NF-κB is activated after menopause, and how NF-κB acts as a common signaling molecule for postmenopausal weight gain and bone loss. Therefore, we examined the role of NF-κB in bone and energy metabolism following menopause. NF-κB reporter mice, which can be used to measure NF-κB activation in vivo, were ovariectomized (OVX) and the luminescence intensity after OVX increased in the metaphyses of the long bones and perigonadal white adipose tissue, but not in the other tissues. OVX was performed on wild-type (WT) and p65 mutant knock-in (S534A) mice, whose mutation enhances the transcriptional activity of NF-κB. Weight gain with worsening glucose tolerance was significant in S534A mice after OVX compared with those of WT mice. The bone density of the sham group in WT or S534A mice did not change, whereas in the S534A-OVX group it significantly decreased due to the suppression of bone formation and increase in bone marrow adipocytes. Disulfiram, an anti-alcoholic drug, suppressed OVX-induced activation of NF-κB in the metaphyses of long bones and white adipose tissue (WAT), as well as weight gain and bone loss. Overall, the activation of NF-κB in the metaphyses of long bones and WAT after OVX regulates post-OVX weight gain and bone loss (241 words).
PubMed: 38936515
DOI: 10.1016/j.bbadis.2024.167320 -
Advanced Biology Jun 2024New-QiangGuYin (N-QGY), the addition of sea buckthorn on the basis of QGY formula, is herbal formula widely used clinically in China for the treatment of osteoporosis...
New-QiangGuYin (N-QGY), the addition of sea buckthorn on the basis of QGY formula, is herbal formula widely used clinically in China for the treatment of osteoporosis (OP), but its mechanism warrants further exploration. The mechanisms of QGY and N-QGY in the treatment of OP are probed from the perspective of osteoclast-osteoblast balance. Thirty Sprague-Dawley rats are randomly divided into N-QGY group, QGY group, and Control group. Beyond control rats that orally took normal saline, other rats are orally administered with isometric N-QGY or QGY twice every day for 3 days. The drug-containing serum and control serum are prepared and their effects on osteoclast-derived exosome secretion are determined by bicinchoninic acid assay (BCA), nanoparticle tracking analysis, and Western blot. GW4869 and Interleukin-1β (IL-1β) are adopted as the exosome inhibitor and inducer, respectively. Exosome uptake, cell counting kit-8, alkaline phosphatase (ALP) staining, alizarin red staining, enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, and Western blot are performed to examine the effects of altered osteoclast exosome content on osteogenic differentiation of mesenchymal stem cells (MSCs). N-QGY, QGY, and GW4869 inhibit osteoclast-derived exosome secretion and exosome uptake by MSCs, whereas IL-1β exerted the opposite effects (p < 0.05). Different from IL-1β, N-QGY, QGY, and GW4869 partially elevated MSC viability, osteocalcin secretion, ALP, RUNX Family Transcription Factor 2 (RUNX2) and Osteopontin (OPN) expressions, and calcium deposition in the osteoclast-MSCs coculture system (p < 0.05). Mechanically, osteoclasts increased Notum protein level but decreased β-catenin level, which is enhanced by IL-1β but is reversed by GW4869, QGY, and N-QGY (p < 0.05). And the effect of N-QGY is more conspicuous than that of QGY (P<0.05). N-QGY-containing serum inhibits exosome levels in osteoclasts, thereby enhancing osteogenic differentiation of MSCs via inhibition of Notum protein and promotion of β-catenin protein.
PubMed: 38935529
DOI: 10.1002/adbi.202400166 -
Amino Acids Jun 2024Exogenous polyamines, including putrescine (PUT), spermidine (SPD), and spermine (SPM), and the irreversible inhibitor of the rate-limiting enzyme ornithine...
Exogenous polyamines, including putrescine (PUT), spermidine (SPD), and spermine (SPM), and the irreversible inhibitor of the rate-limiting enzyme ornithine decarboxylase (ODC) of polyamine biosynthesis, α-difluoromethylornithine (DFMO), are implicated as stimulants for bone formation. We demonstrate in this study the osteogenic potential of exogenous polyamines and DFMO in human osteoblasts (hOBs), murine monocyte cell line RAW 264.7, and an ovariectomized rat model. The effect of polyamines and DFMO on hOBs and RAW 264.7 cells was studied by analyzing gene expression, alkaline phosphatase (ALP) activity, tartrate-resistant acid phosphatase (TRAP) activity, and matrix mineralization. Ovariectomized rats were treated with polyamines and DFMO and analyzed by micro computed tomography (micro CT). The mRNA level of the early onset genes of osteogenic differentiation, Runt-related transcription factor 2 (Runx2) and ALP, was significantly elevated in hOBs under osteogenic conditions, while both ALP activity and matrix mineralization were enhanced by exogenous polyamines and DFMO. Under osteoclastogenic conditions, the gene expression of both receptor activator of nuclear factor-κB (RANK) and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) was reduced, and TRAP activity was suppressed by exogenous polyamines and DFMO in RAW 264.7 cells. In an osteoporotic animal model of ovariectomized rats, SPM and DFMO were found to improve bone volume in rat femurs, while trabecular thickness was increased in all treatment groups. Results from this study provide in vitro and in vivo evidence indicating that polyamines and DFMO act as stimulants for bone formation, and their osteogenic effect may be associated with the suppression of osteoclastogenesis.
Topics: Animals; Mice; Osteoclasts; Osteogenesis; Rats; Humans; Cell Differentiation; Eflornithine; Female; Polyamines; Osteoblasts; RAW 264.7 Cells; Ovariectomy; Rats, Sprague-Dawley; Spermidine
PubMed: 38935136
DOI: 10.1007/s00726-024-03403-8 -
Indian Journal of Dental Research :... Jan 2024Periodontitis and type 2 diabetes are chronic inflammatory diseases that increase inflammatory Interleukin-6 (IL-6) levels that induce the production of advanced...
BACKGROUND
Periodontitis and type 2 diabetes are chronic inflammatory diseases that increase inflammatory Interleukin-6 (IL-6) levels that induce the production of advanced glycation end products (AGEs) causing receptor activator of nuclear factor-kappa B ligand (RANKL) expression on osteoclasts, contributing to further alveolar bone destruction.
AIM
To assess the role and diagnostic potential of salivary IL-6 (SIL-6) in the detection and evaluation of chronic periodontitis (CP) and tooth loss in type 2 diabetes mellitus (T2DM).
MATERIALS AND METHODS
This cross-sectional study comprised 240 subjects aged 30-69 years with minimum of 15 natural teeth. Fasting, unstimulated whole saliva was collected, full-mouth intra-oral examination and periodontal evaluation were performed using PCP-UNC 15 probe and glycaemic (HbA1c) levels were analysed by high-performance liquid chromatography (HPLC) method. Subjects were categorised into four groups of 60 participants each: Group 1 (controls); Group 2 (CP); Group 3 (T2DM with CP); Group 4 (T2DM with CP and tooth loss). Salivary IL-6 levels were quantitatively assessed by enzyme-linked immune sorbent assay method.
RESULTS
Average SIL-6 levels were significantly elevated in Group 4 (T2DM with CP and tooth loss) (P = 0.001) and in severe periodontitis (P = 0.001). Karl Pearson Correlation found a significant association between average SIL-6 and average periodontal pocket depth (APPD) (r = 0.180), average clinical attachment loss ≥3 mm (ACAL3) (r = 0.289) and severity of periodontitis (r = 0.3228). The receiver operating characteristic (ROC) curve depicted an overall sensitivity of 53.3%, specificity of 68.6% and accuracy of 60% in the detection and assessment of CP in T2DM with tooth loss.
CONCLUSION
IL-6 in saliva is a valuable, non-invasive biomarker in the detection and evaluation of CP in T2DM with tooth loss.
Topics: Humans; Chronic Periodontitis; Middle Aged; Interleukin-6; Saliva; Biomarkers; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Tooth Loss; Adult; Male; Aged
PubMed: 38934745
DOI: 10.4103/ijdr.ijdr_112_23 -
Cell Biology International Jun 2024This study explores the potential role and mechanism of Ginsenoside Rb3 (Rb3) in modulating osteoclastogenesis induced by human periodontal ligament fibroblasts (hPLFs)...
This study explores the potential role and mechanism of Ginsenoside Rb3 (Rb3) in modulating osteoclastogenesis induced by human periodontal ligament fibroblasts (hPLFs) within the periodontitis microenvironment. We investigated the anti-inflammatory effects of Rb3 on hPLFs stimulated with Porphyromonas gingivalis lipopolysaccharide (P.g-LPS) utilizing quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay techniques. Moreover, the functional role of Rb3 in hPLFs-induced osteoclast formation was assessed by treating human bone marrow-derived macrophages (hBMMs) with conditioned medium from hPLFs, followed by analyses through qPCR, western blot analysis, and staining for tartrate-resistant acid phosphatase (TRAP) and phalloidin. The impact of Rb3 on the activation of the STAT3 signaling pathway was determined via western blot analysis. Results indicated that Rb3 treatment significantly suppressed the upregulation of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, MCP-1, and IL-18) at both gene and protein levels in hPLFs induced by P.g-LPS. Furthermore, conditioned medium from Rb3 plus P.g-LPS treated hPLFs notably decreased the number of TRAP-positive cells, actin ring formations, and the expression of osteoclast marker genes (including CTSK, NFATC1, and ACP5). Rb3 also inhibited the P.g-LPS-induced activation of the STAT3 pathway, with the activation of STAT3 partially reversing the effects of Rb3 on inflammation and osteoclast differentiation. Collectively, Rb3 ameliorates inflammation in P.g-LPS-stimulated hPLFs and reduces hPLFs-induced osteoclastogenesis by inhibiting the STAT3 signaling pathway, suggesting its potential as a therapeutic agent for periodontitis.
PubMed: 38934258
DOI: 10.1002/cbin.12201 -
Acta Endocrinologica (Bucharest,... 2023Reactive oxygen species (ROS) produced under oxidative stress is important for osteoclastogenesis. As a major member of the metallothionein (MT) family, metallothionein2...
CONTEXT AND OBJECTIVE
Reactive oxygen species (ROS) produced under oxidative stress is important for osteoclastogenesis. As a major member of the metallothionein (MT) family, metallothionein2 (MT2) can scavenge ROS in osteoblasts. However, the role of MT2 in osteoclastogenesis and ROS production in osteoclast precursors (OCPs) is unknown.
MATERIAL AND METHODS
In this study, we first investigated MT2 expression level in osteoporotic model mice. Next, we explored the roles of MT2 in osteoclastic differentiation and ROS production in OCPs. Ultimately, via rescue assays based on hydrogen peroxide (HO), the significance of ROS in MT-2-regulated osteoclastic differentiation was further elucidated.
RESULTS
Compared with sham operated (Sham) mice, ovariectomized (OVX) mice displayed bone marrow primary OCPs (Ly6C+CD11b-) having higher ROS levels and lower MT2 expression. MT2 overexpression inhibited the formation of mature osteoclasts, while MT2 knockdown was contrary. Moreover, MT2 overexpression inhibited ROS production in OCPs, while MT2 knockdown exhibited the opposite effects. Notably, the inhibitory effect of MT2 overexpression on osteoclastogenesis and ROS production was blocked by the addition of HO.
CONCLUSION
MT2 inhibits osteoclastogenesis through repressing ROS production in OCPs, which indicates that the strategy of upregulating MT2 in OCPs may be applied to the clinical treatment of osteoclastic bone loss.
PubMed: 38933247
DOI: 10.4183/aeb.2023.447 -
Diagnostic Cytopathology Jun 2024Tenosynovial giant cell tumors (TGCTs) arise from the synovium of joint, bursa, and tendon sheath. Diffuse type often affects large joints, has higher recurrence rates,...
Tenosynovial giant cell tumors (TGCTs) arise from the synovium of joint, bursa, and tendon sheath. Diffuse type often affects large joints, has higher recurrence rates, metastases, and malignant transformation potential compared to the localized type. The cytopathology of TGCT, a fibrohistiocytic neoplasm distinct from other giant cell-rich soft tissue tumors, is rarely reported. Here we describe cytomorphology of a case of TGCT that was initially diagnosed on fine-needle aspiration cytology (FNAC) consisting of a mixture of singly scattered polygonal or spindle mononuclear cells with hemosiderin laden macrophages, inflammatory cells, and a population of multinucleated osteoclast-like giant cells. Persistent symptoms and repeat excision were consistent with high-grade malignant transformation of the TGCT. Atypical cytologic features in a recurrent, infiltrative, or a metastatic lesion should raise suspicion for malignancy.
PubMed: 38932656
DOI: 10.1002/dc.25338