Eldecalcitol prevented OVX-induced osteoporosis through inhibiting BMSCs senescence by regulating the SIRT1-Nrf2 signal

6'-O-caffeoylarbutin attenuates D-galactose-induced brain and liver damage in aging mice via regulating SIRT1/NF-κB pathway

BACKGROUND

Aging-related liver and brain damage caused by oxidative stress and inflammation significantly impacts health and quality of life. Natural bioactive compounds, such as 6'-O-caffeoylarbutin (CA), which is primarily distributed in Vaccinium species, have been studied for their antioxidant and anti-inflammatory properties. This study aims to investigate the protective effect on liver and brain damage induced by D-galactose (D-gal) in mice and to explore its potential molecular mechanisms.

PURPOSE

This study aims to investigate the protective effects of CA on D-galactose (D-gal)-induced liver and brain damage in mice and to explore its potential molecular mechanisms.

METHODS

CA was prepared from Vaccinium dunalianum and identified using UHPLC-ESI-HR-MS/MS. Molecular docking and network pharmacology analysis were performed to predict the binding of CA with SIRT1 and NF-κB1 targets. In vivo, a D-gal-induced aging mouse model was established to evaluate the biochemical, oxidative stress, and inflammatory parameters. The effects of CA on oxidative stress and inflammation were examined through enzymatic activity assays, cytokine level measurements, and histopathological analysis. Western blotting was used to validate the involvement of the SIRT1/NF-κB pathway.

RESULTS

CA treatment significantly alleviated liver and brain damage in D-gal-induced mice by decreasing AChE, AST, and ALT activities, improving organ indices, and reducing histopathological alterations. CA enhanced antioxidant defense by increasing SOD, CAT, and T-AOC activities, elevating GSH levels, and decreasing MDA content. Furthermore, CA suppressed the inflammatory response by downregulating IL-6 and TNF-α levels. Mechanistically, CA inhibited NF-κB p65 phosphorylation and suppressed iNOS and COX-2 expression, likely via activation of the SIRT1 protein.

CONCLUSION

This study demonstrates that CA protects against D-gal-induced oxidative stress and inflammation in liver and brain tissues via the SIRT1/NF-κB pathway, supporting its potential as a bioactive compound for preventing aging-related liver and brain damage.

Antisenescence therapies for age-related bone loss: Target factors, medicines, biomedical materials

Progress in living conditions and medical technology have extended the human life span such that population aging, and thus the development of multi-system degenerative diseases, has become a major problem in many countries. Bone is a metabolically dynamic tissue and bone aging is closely related to a shift in the balance between bone resorption and bone formation. The resulting loss of bone mass and bone mechanical properties in older adults place them at risk of injury and premature death. Cellular senescence occurs in response to endogenous and exogenous stresses that lead to permanent cell cycle arrest and, thus, to tissue degeneration and dysfunction. Senescence in the bone microenvironment, as occurs during aging, induces a decline in bone formation. Research into the treatment of bone aging has therefore focused on the senescence process. This review begins with a summary of the key events in cellular senescence and bone aging and then examines recent progress in the targeting of cellular senescence, both to treat aging-related bone diseases. Novel therapeutic agents, natural products, and innovative biomedical materials are considered. Our discussion concludes by considering areas of future research.

Nanomaterials-Based Drug Delivery Systems for Therapeutic Applications in Osteoporosis

The etiology of osteoporosis is rooted in the disruption of the intricate equilibrium between bone formation and bone resorption processes. Nevertheless, the conventional anti-osteoporotic medications and hormonal therapeutic regimens currently employed in clinical practice are associated with a multitude of adverse effects, thereby constraining their overall therapeutic efficacy and potential. Recently, nanomaterials have emerged as a promising alternative due to their minimal side effects, efficient drug delivery, and ability to enhance bone formation, aiding in restoring bone balance. This review delves into the fundamental principles of bone remodeling and the bone microenvironment, as well as current clinical treatment approaches for osteoporosis. It subsequently explores the research status of nanomaterial-based drug delivery systems for osteoporosis treatment, encompassing inorganic nanomaterials, organic nanomaterials, cell-mimicking carriers and exosomes mimics and emerging therapies targeting the osteoporosis microenvironment. Finally, the review discusses the potential of nanomedicine in treating osteoporosis and outlines the future trajectory of this burgeoning field. The aim is to provide a comprehensive reference for the application of nanomaterial-based drug delivery strategies in osteoporosis therapy, thereby fostering further advancements and innovations in this critical area of medical research.

ED-71 promotes osseointegration of titanium implants in a rat model of GIOP by alleviating the effects of dexamethasone on bone remodeling in a SIRT1-dependent manner

OBJECTIVE

Glucocorticoid-induced osteoporosis (GIOP), a common complication of glucocorticoid usage, plays a critical role in the success of dental implant restoration by affecting osseointegration. Eldecalcitol (ED-71) prevents GIOP; however, its role in the osseointegration of implants under GIOP conditions remains elusive.

METHODS

Dexamethasone was used to establish a rat model of GIOP. Subsequently, mini-implant surgery was performed on the femur. GIOP rats were administered ED-71 via gavage to assess its role in the osseointegration of titanium implants under GIOP conditions. MC3T3-E1 and RAW264.7 cells were utilized to explore the molecular mechanism of ED-71 in ameliorating disorder of bone remodeling caused by dexamethasone.

RESULTS

The administration of ED-71 promoted the formation of newly formed woven bone and the resolution of inflammation around titanium implants. In vitro experiments indicated that ED-71 ameliorated dexamethasone-induced dysfunction of osteoblasts and osteoclasts by increasing the expression level of sirtuin 1 (SIRT1). Inhibition of SIRT1 by selisistat counteracts the regulatory effects of ED-71 on dexamethasone-induced disorder of bone remodeling. Molecular docking and Western blotting revealed that the neurogenic locus notch homolog protein and nuclear factor kappa B signaling pathways are essential for the effects of ED-71 on dexamethasone-induced disorder of bone remodeling.

CONCLUSION

ED-71 promoted implant osseointegration in a rat model of GIOP by alleviating the effects of dexamethasone on bone remodeling in a SIRT1-dependent manner.

Rejuvenation of Bone Marrow Mesenchymal Stem Cells: Mechanisms and Their Application in Senile Osteoporosis Treatment

Bone marrow mesenchymal stromal cells (BM-MSCs) are multipotent cells present in bone marrow; they play a crucial role in the process of bone formation. Cellular senescence is defined as a stable state of cell cycle arrest that impairs the functioning of cells. Research has shown that aging triggers a state of senescence in BM-MSCs, leading to a reduced capacity for osteogenic differentiation and the accumulation of senescent cells, which can accelerate the onset of various diseases. Therefore, it is essential to explore mechanisms and strategies for the rejuvenation of senescent BM-MSCs. Senile osteoporosis (SOP) is a metabolic bone disease characterized by reduced bone formation. The senescence of BM-MSCs is considered one of the most important factors in the occurrence and development of SOP. Therefore, the rejuvenation of BM-MSCs for the treatment of SOP represents a promising strategy. This work provides a summary of the functional alterations observed in senescent BM-MSCs and a systematic review of the mechanisms that facilitate the rejuvenation of senescent BM-MSCs. Additionally, we analyze the progress in and the limitations associated with the application of rejuvenated senescent BM-MSCs to treat SOP, with the aim of providing new insights for the prevention and treatment of SOP.

Asperuloside alleviates osteoporosis by promoting autophagy and regulating Nrf2 activation

BACKGROUND

Osteoporosis is a metabolic bone disease that has a common occurrence in postmenopausal women. Asperuloside (ASP) has been reported to exert anti-inflammatory and anti-oxidative effects in numerous diseases, such as rheumatoid arthritis and acute lung injury. However, whether ASP plays a role in osteoporosis has not been addressed.

METHODS

In vivo, ovariectomy (OVX) was used to induce mouse osteoporosis. Then, the mice were treated with 20 and 40 mg/kg ASP. In vitro, MC3T3-E1 cells were treated with 0, 1, 10, 20, 40 and 80 µM ASP. We chose 20 and 40 µM for further experiments due to no significant effects on cell viability.

RESULTS

The data indicated that ASP reduced osteoporosis in OVX mice and promoted osteogenic differentiation and mineralization in MC3T3-E1 cells. In addition, we explored that ASP protected against osteoporosis via inducing autophagy and activating Nrf2.

CONCLUSION

ASP alleviates OVX-induced osteoporosis by promoting autophagy and regulating Nrf2 activation.

Syringin protects high glucose-induced BMSC injury, cell senescence, and osteoporosis by inhibiting JAK2/STAT3 signaling

BACKGROUND

Acanthopanax senticosus (Rupr. et Maxim.) is commonly used in Traditional Chinese Medicine. Syringin is a major ingredient of phenolic glycoside in Acanthopanax senticosus.

OBJECTIVE

This study was performed to investigate whether Syringin could protect high glucose-induced bone marrow mesenchymal stem cells (BMSCs) injury, cell senescence, and osteoporosis by inhibiting JAK2/STAT3 signaling.

METHODS

BMSCs isolated from both the tibia and femur of mice were induced for osteogenesis. The cell senescence was induced using the high glucose medium. The cells were treated with 10 and 100 μmol/l Syringin. Immunohistochemistry staining was performed to determine the β-galactosidase (SA-β-gal) levels in differentially treated BMSCs. MTT assay and flow cytometry analysis were also performed to assess cell viability and cell cycle. The level of ROS in cells with different treatment was measured by using flow cytometry with DCF-DA staining. Calcium deposition and mineralized matrices were detected with alizarin red and ALP staining, respectively. Osteogenesis related genes OCN, ALP, Runx2, and BMP-2 were detected by RT-PCR. Levels of senescence-related proteins including p53 and p21, as well as JAK2, p-JAK2, STAT3, and p-STAT3 were detected by Western blot analysis.

RESULTS

Syringin treatment reversed the phenotypes of senescence caused by high glucose in BMSCs, including the arrest of G0/G1 cell cycle, enhanced SA-β-gal activity, and impaired cell growth. Syringin also decreased the elevated ROS production and the levels of p53, p21, and JAK2/STAT3 signaling activation. In addition, Syringin also enhanced the osteogenic potential determined by ARS and ALP staining, as well as increasing OCN, ALP, Runx2, and BMP-2 expressions.

CONCLUSION

Syringin protects high glucose-induced BMSC injury, cell senescence, and osteoporosis by inhibiting JAK2/STAT3 signaling.

Bazi Bushen attenuates osteoporosis in SAMP6 mice by regulating PI3K-AKT and apoptosis pathways

Osteoporosis (OP), a systemic skeletal disease, is characterized by low bone mass, bone tissue degradation and bone microarchitecture disturbance. Bazi Bushen, a Chinese patented medicine, has been demonstrated to be effective in attenuating OP, but the pharmacological mechanism remains predominantly unclear. In this study, the senescence-accelerated mouse prone 6 (SAMP6) model was used to explore bone homeostasis and treated intragastrically for 9 weeks with Bazi Bushen. In vivo experiments showed that Bazi Bushen treatment not only upregulated the levels of bone mineral density and bone mineral content but also increased the content of RUNX2 and OSX. Furthermore, the primary culture of bone mesenchymal stem cells (BMSCs) in SAMP6 mice was used to verify the effects of Bazi Bushen on the balance of differentiation between osteoblasts and adipocytes, as well as ROS and aging levels. Finally, the pharmacological mechanism of Bazi Bushen in attenuating OP was investigated through network pharmacology and experimental verification, and we found that Bazi Bushen could significantly orchestrate bone homeostasis and attenuate the progression of OP by stimulating PI3K-Akt and inhibiting apoptosis. In summary, our work sheds light on the first evidence that Bazi Bushen attenuates OP by regulating PI3K-AKT and apoptosis pathways to orchestrate bone homeostasis.

ED-71 Ameliorates Bone Loss in Type 2 Diabetes Mellitus by Enhancing Osteogenesis Through Upregulation of the Circadian Rhythm Coregulator BMAL1

Purpose

Bone loss is a common complication of type 2 diabetes mellitus (T2DM). Circadian rhythms play a significant role in T2DM and bone remodeling. Eldecalcitol (ED-71), a novel active vitamin D analog, has shown promise in ameliorating T2DM. We aimed to investigate whether the circadian rhythm coregulator BMAL1 mediates the anti-osteoporotic effect of ED-71 in T2DM and its associated mechanisms.

Methods

A T2DM mouse model was established using high-fat diet (HDF) and streptozotocin (STZ) injection, and blood glucose levels were monitored weekly. HE staining, Masson staining, and Micro-CT were performed to assess the changes in bone mass. IHC staining and IF staining were used to detect osteoblast status and BMAL1 expression and RT-qPCR was applied to detect the change of oxidative stress factors. In vitro, high glucose (HG) stimulation was used to simulate the cell environment in T2DM. RT-qPCR, Western blot, IF, ALP staining and AR staining were used to detect osteogenic differentiation and SIRT1/GSK3β signaling pathway. DCFH-DA staining was used to detect reactive oxygen species (ROS) levels.

Results

ED-71 increased bone mass and promoted osteogenesis in T2DM mice. Moreover, ED-71 inhibited oxidative stress and promoted BMAL1 expression in osteoblasts The addition of STL1267, an agonist of the BMAL1 transcriptional repressor protein REV-ERB, reversed the inhibitory effect of ED-71 on oxidative stress and the promotional effect on osteogenic differentiation. In addition, ED-71 facilitated SIRT1 expression and reduced GSK3β activity. The inhibition of SIRT1 with EX527 partially attenuated ED-71's effects, whereas the GSK3β inhibitor LiCl further enhanced ED-71's positive effects on BMAL1 expression.

Conclusion

ED-71 ameliorates bone loss in T2DM by upregulating the circadian rhythm coregulator BMAL1 and promoting osteogenesis through inhibition of oxidative stress. The SIRT1/GSK3β signaling pathway is involved in the regulation of BMAL1.

Qianggu concentrate: unlocking bone protection power via antioxidative SIRT1/NRF2/HO-1 pathways in type 2 diabetic osteoporosis

Background

Qianggu Concentrate (QGHJ), a traditional Chinese medicine, is extensively used to treat Type 2 Diabetic Osteoporosis (T2DOP). Despite its widespread use, research on its therapeutic mechanisms within T2DOP is notably scarce.

Objective

To explore QGHJ's osteoprotection in T2DOP rats and BMSCs, focusing on the antioxidant activation of SIRT1/NRF2/HO-1 and NRF2 nuclear migration.

Methods

QGHJ constituent analysis was performed using UPLC-HRMS. Safety, bone-health efficacy, and glucose metabolic effects in T2DOP rats were evaluated via general condition assessments, biomarker profiling, micro-CT, biomechanics, staining methods, and ELISA, supplemented by RT-qPCR and Western blot. BMSCs' responses to QGHJ under oxidative stress, including viability, apoptosis, and osteogenic differentiation, were determined using CCK-8, flow cytometry, ALP/ARS staining, and molecular techniques. The modulation of the SIRT1/NRF2/HO-1 pathway by QGHJ was explored through oxidative stress biomarkers, immunofluorescence, and Western blot assays.

Results

UPLC-HRMS identified flavonoids, monoterpenes, and isoflavones as QGHJ's key compounds. In vivo, QGHJ proved safe and effective for T2DOP rats, enhancing bone mineral density, microenvironment, and biomechanical properties without impairing vital organs. It modulated bone markers PINP, TRACP 5b, RUNX2 and PPARγ, favoring bone anabolism and reduced catabolism, thus optimizing bone integrity. QGHJ also regulated glycemia and mitigated insulin resistance. In vitro, it preserved BMSCs' viability amidst oxidative stress, curbed apoptosis, and fostered osteogenesis with regulated RUNX2/PPARγ expression. Mechanistic insights revealed QGHJ activated the SIRT1/NRF2/HO-1 pathway, augmented NRF2 nuclear translocation, and enhanced the antioxidative response, promoting bone health under stress.

Conclusion

In T2DOP rat and BMSCs oxidative stress models, QGHJ's bone protection is anchored in its antioxidative mechanisms via the SIRT1/NRF2/HO-1 pathway activation and NRF2 nuclear translocation.

Sirt1: An Increasingly Interesting Molecule with a Potential Role in Bone Metabolism and Osteoporosis

Osteoporosis (OP) is a common metabolic bone disease characterized by low bone mass, decreased bone mineral density, and degradation of bone tissue microarchitecture. However, our understanding of the mechanisms of bone remodeling and factors affecting bone mass remains incomplete. Sirtuin1 (SIRT1) is a nicotinamide adenine dinucleotide-dependent deacetylase that regulates a variety of cellular metabolisms, including inflammation, tumorigenesis, and bone metabolism. Recent studies have emphasized the important role of SIRT1 in bone homeostasis. This article reviews the role of SIRT1 in bone metabolism and OP and also discusses therapeutic strategies and future research directions for targeting SIRT1.

ED-71 Improves Bone Mass in Ovariectomized Rats by Inhibiting Osteoclastogenesis Through EphrinB2-EphB4-RANKL/OPG Axis

Purpose

Estrogen deficiency is the main reason of postmenopausal osteoporosis. Eldecalcitol (ED-71) is a new active vitamin D analogue clinically used in the treatment of postmenopausal osteoporosis. We aimed to investigate whether EphrinB2-EphB4 and RANKL/RANK/OPG signaling cooperate in mediating the process of osteoporosis by ED-71.

Methods

In vivo, the ovariectomized (OVX) rats were administered orally with 30 ng/kg ED-71 once a day for 8 weeks. HE staining, Masson staining and Immunofluorescence staining were used to evaluate bone mass, bone formation, osteoclastogenesis associated factors and the expression of EphrinB2, EphB4, RANKL and OPG. In vitro, H2O2 stimulation was used to simulate the cell environment in osteoporosis. Immunofluorescence, quantitative real time PCR (qRT-PCR), enzyme-linked immunosorbent assay (ELISA) and Western Blot were applied to detect the expression of EphrinB2, EphB4, RANKL and OPG. In osteoblasts, EphB4 was knocked down by EphB4 small-interfering RNA (siRNA) transfection. LY294002 (PI3K inhibitor) or ARQ092 (AKT inhibitor) was used to block PI3K/AKT pathway. An indirect co-culture system of osteoblasts and osteoclasts was established. The mRNA and protein expression of osteoclastogenes is associated factors were tested by qRT-PCR and Western Blot.

Results

ED-71 increased bone mass and decreased the number of osteoclasts in OVX rats. Moreover, ED-71 promoted the expression of EphrinB2, EphB4, and decreased the RANKL/OPG ratio in osteoblasts. Osteoclastogenesis was restrained when osteoclasts were indirectly co-cultured with ED-71-treated osteoblasts. After silencing of EphB4 expression in osteoblasts, ED-71 inhibited the expression of P-PI3K and P-AKT and increased the ratio of RANKL/OPG. This reversed the inhibitory effect of ED-71 on osteoclastogenes. Therefore, in ED-71-inhibited osteoclastogenes, EphB4 is a key factor affecting the secretion of RANKL and OPG by osteoblasts. EphB4 suppressed the RANKL/OPG ratio through activating PI3K/AKT signaling in osteoblasts.

Conclusion

ED-71 inhibits osteoclastogenesis through EphrinB2-EphB4-RANKL/OPG axis, improving bone mass in ovariectomized rats. PI3K/AKT pathway is involved this process.

Eldecalcitol protected osteocytes against ferroptosis of D-gal-induced senescent MLO-Y4 cells and ovariectomized mice

BACKGROUND

Active vitamin D analog eldecalcitol is clinically applied in treatment of postmenopausal osteoporosis. This study aims to determine the role of eldecalcitol in the protection of osteocytes from senescence and the associated ferroptosis.

METHODS

The MLO-Y4 osteocytes were exposed to D-gal inducing senescence. The ovariectomized (OVX) mice treated with D-gal using as an aging inducer were intraperitoneally injected with eldecalcitol. The multiplexed confocal imaging, fluorescence in situ hybridization and transmission electron microscopy were applied in assessing osteocytic properties. Immunochemical staining and immunoblotting were carried out to detect abundance and expression of molecules.

RESULTS

The ablation of vitamin D receptor led to a reduction in amounts of osteocytes, a loss of dendrites, an increase in mRNA expression of SASP factors and in protein expression of senescent factors, as well as changes in mRNA expression of ferroptosis-related genes (PTGS2 & RGS4). Eldecalcitol reversed senescent phenotypes of MLO-Y4 cells shown by improving cell morphology and density, decreasing β-gal-positive cell accumulation, and down-regulating protein expression (P16, P21 & P53). Eldecalcitol reduced intracellular ROS and MDA productions, elevated JC-1 aggregates, and up-regulated expression of Nrf2 and GPX4. Eldecalcitol exhibited osteopreserve effects in D-gal-induced aging OVX mice. The confocal imaging displayed its improvement on osteocytic network organization. Eldecalcitol decreased the numbers of senescent osteocytes at tibial diaphysis by SADS assay and attenuated mRNA expression of SASP factors as well as down-regulated protein expression of senescence-related factors and restored levels of ferroptotic biomarkers in osteocytes-enriched bone fraction. It reduced 4-HNE staining area, stimulated Nrf2-positive staining, and promoted nuclear translocation of Nrf2 in osteocytes of mice as well as inhibited and promoted protein expression of 4-HNE and Nrf2, respectively, in osteocytes-enriched bone fraction.

CONCLUSIONS

The present study revealed the ameliorative effects of eldecalcitol on senescence and the associated ferroptosis of osteocytes, contributing to its preservation against osteoporosis of D-gal-induced senescent ovariectomized mice.

Mitigation of Cardiovascular Disease and Toxicity through NRF2 Signalling

Cardiovascular toxicity and diseases are phenomena that have a vastly detrimental impact on morbidity and mortality. The pathophysiology driving the development of these conditions is multifactorial but commonly includes the perturbance of reactive oxygen species (ROS) signalling, iron homeostasis and mitochondrial bioenergetics. The transcription factor nuclear factor erythroid 2 (NFE2)-related factor 2 (NRF2), a master regulator of cytoprotective responses, drives the expression of genes that provide resistance to oxidative, electrophilic and xenobiotic stresses. Recent research has suggested that stimulation of the NRF2 signalling pathway can alleviate cardiotoxicity and hallmarks of cardiovascular disease progression. However, dysregulation of NRF2 dynamic responses can be severely impacted by ageing processes and off-target toxicity from clinical medicines including anthracycline chemotherapeutics, rendering cells of the cardiovascular system susceptible to toxicity and subsequent tissue dysfunction. This review addresses the current understanding of NRF2 mechanisms under homeostatic and cardiovascular pathophysiological conditions within the context of wider implications for this diverse transcription factor.