Targeting ferroptosis suppresses osteocyte glucolipotoxicity and alleviates diabetic osteoporosis

Faecalibacterium prausnitzii prevents age-related heart failure by suppressing ferroptosis in cardiomyocytes through butyrate-mediated LCN2 regulation

Aging is a primary driver of the escalating prevalence of heart failure (HF). Age-associated gut microbiota dysbiosis has been implicated in various age-related diseases, yet its role in age-related HF remains largely unexplored. In this study, we sought to explore the potential link between age-related gut microbiota alterations and HF in the elderly. We analyzed a publicly available single-cell sequencing dataset, which revealed markedly increased ferroptosis activity in cardiac myocytes of elderly individuals compared to their younger counterparts. Notably, treatment with the ferroptosis inhibitor, ferrostatin-1, mitigated cardiac ferroptosis and prevented cardiac dysfunction in aging rats. Furthermore, fecal microbiota transplantation from elderly HF patients significantly increased cardiac ferroptosis activity and induced cardiac dysfunction in healthy recipient rats. Integrated 16S rRNA sequencing and PCR quantification revealed a marked depletion of Faecalibacterium prausnitzii (F. prausnitzii) in elderly individuals, with a more pronounced decline in elderly patients with HF. Oral administration of F. prausnitzii or its metabolite butyrate effectively attenuated age-related HF through inhibiting ferroptosis. Additionally, gene-editing techniques were employed to generate F. prausnitzii BCoAT mutant deficient in butyrate production. Intriguingly, the protective effect was lost in the butyrate-deficient F. prausnitzii strain. Mechanistically, butyrate reduced intracellular iron accumulation and suppressed ferroptosis by downregulating LCN2 expression in senescent cardiomyocytes. Our findings highlight the critical role of aged microbiota-induced ferroptosis in HF and propose F. prausnitzii or butyrate may serve as potential targets for the prevention and treatment of age-related HF.

Iron dysregulation, ferroptosis, and oxidative stress in diabetic osteoporosis: Mechanisms, bone metabolism disruption, and therapeutic strategies

Diabetic osteoporosis (DOP) is a common complication in diabetes, driven by hyperglycemia-induced metabolic disturbances, chronic inflammation, and oxidative stress. This review describes the critical role of iron metabolism dysregulation in DOP pathogenesis, focusing on ferroptosis, a novel iron-dependent cell death pathway characterized by lipid peroxidation and reactive oxygen species (ROS) overproduction. Diabetic conditions exacerbate iron overload, impairing osteoblast function and enhancing osteoclast activity, while triggering ferroptosis in bone cells. Ferroptosis not only accelerates osteoblast apoptosis but also amplifies osteoclast-mediated bone resorption, synergistically promoting bone loss. Furthermore, chronic inflammation and oxidative stress disrupt the balance between bone formation and resorption, with elevated pro-inflammatory cytokines (e.g., tumor necrosis factor-α, interleukin-6) and ROS exacerbating cellular dysfunction. Therapeutic strategies targeting iron metabolism (e.g., deferoxamine) and ferroptosis inhibition (e.g., nuclear factor erythroid 2-related factor 2/heme oxygenase-1 pathway activation, antioxidants like melatonin) demonstrate potential to mitigate DOP progression. Future research should prioritize personalized interventions, clinical trials of iron chelators and antioxidants, and mechanistic studies to refine therapeutic approaches. This review provides a comprehensive framework for understanding DOP pathogenesis and highlights innovative strategies to improve bone health in diabetic patients.

METTL9 mediated N1-Histidine methylation of SLC39A7 confers ferroptosis resistance and inhibits adipogenic differentiation in mesenchymal stem cells

Osteoporosis is a prevalent systemic metabolic disease, and an imbalance in the adipogenic and osteogenic differentiation of mesenchymal stem cells (MSCs) plays a crucial role in its pathogenesis. Thus, elucidating the mechanisms that regulate MSC lineage allocation is urgently needed. METTL9 was recently characterized as a novel N1-histidine methyltransferase that performs a wide range of functions. however, the role of METTL9 in the imbalance of MSC differentiation in osteoporosis remains unclear. In this study, we found that METTL9 expression was downregulated in osteoporosis, and further adipogenic functional experiments revealed that METTL9 negatively regulated the adipogenic differentiation of MSCs both in vitro and in vivo. Mechanistically, METTL9 mediated methylation of SLC39A7 at the His45 and His49 residues suppressed ferroptosis through the endoplasmic reticulum (ER) stress regulatory protein kinase R-like endoplasmic reticulum kinase (PERK)/ATF4 signaling pathway and the downstream protein SLC7A11. Moreover, SLC7A11 transported cystine for intracellular glutathione synthesis, eliminating intracellular reactive oxygen species (ROS) and inhibiting MSC adipogenic differentiation. Additionally, METTL9 overexpression significantly alleviated bone loss in ovariectomy (OVX) model mice. In summary, our results suggest that the METTL9/SLC39A7 axis may be a promising diagnostic and therapeutic target for osteoporosis.

Outer membrane vesicles of Porphyromonas gingivalis impede bone regeneration by inducing ferroptosis via the Hippo-YAP signaling pathway

BACKGROUND

Although increasing evidence confirms that oral microbiota imbalance is a critical factor inhibiting bone regeneration, the specific mechanisms have remained unexplored. This study aims to use periodontitis as a model of oral microbiota imbalance to investigate the specific mechanisms that inhibit bone regeneration in extraction sockets.

METHODS

Cone Beam Computed Tomography (CBCT) data of extraction sockets were collected from patients with and without periodontitis to confirm the influence of the periodontitis microenvironment on bone regeneration in extraction sockets. Furthermore, GW4869-pretreated Porphyromonas gingivalis (Pg) and normal Pg were used to build a periodontitis model, and then the bone regeneration in extraction sockets under these conditions was detected by H&E staining, Masson's staining and micro-CT analysis. In vitro, the effect of Pg-derived OMVs on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) was examined. RNA sequencing, FerroOrange, malondialdehyde assay, transmission electron microscopy, qRT‒PCR, and western blotting analysis were performed.

RESULTS

CBCT analysis showed that periodontitis significantly inhibited new bone formation in the extraction sockets in patients. Micro-CT and Histological analysis revealed that inhibiting OMVs released from Pg alleviated the inhibition of bone regeneration in extraction sockets under Pg imbalance. Moreover, Pg-derived OMVs treatment deteriorated bone regeneration in extraction sockets. In vitro, results showed that Pg-derived OMVs inhibited osteogenic differentiation of BMSCs. Furthermore, the results indicated a significant upregulation of ferroptosis in OMVs-treated BMSCs. Notably, targeting ferroptosis promoted osteogenic differentiation of BMSCs and bone regeneration in extraction sockets, as compared with the OMVs-treated group. Mechanistic studies have shown that Pg-derived OMVs promoted BMSCs ferroptosis via the Hippo- Yes-associated protein (YAP) pathway.

CONCLUSION

This study shows that a Pg microbiota imbalance inhibits bone regeneration by secreting OMVs from Pg to induce ferroptosis in BMSCs. Mechanically, we illustrated that OMVs induce ferroptosis through the Hippo-YAP pathway. These findings might provide a new insight and potential therapeutic target to promote bone regeneration under oral microbiota imbalance.

A promising approach to diabetic osteoporosis: oxymatrine's effects on gut microbiota and osteoblasts

OBJECTIVES

Oxymatrine (OMT), a quinolizidine alkaloid derived from Sophora flavescens Ait., has demonstrated therapeutic potential in type 2 diabetes mellitus (T2DM). This study aimed to investigate its effects on diabetic osteoporosis (DOP) and explore the underlying mechanisms involving gut microbiota and osteogenic regulation.

METHODS

In a rat model of T2DM, intragastric Oxymatrine was used to study trabecular bone repair through bone microstructure and histopathology analyses. Changes in gut microbiota, especially Gram-negative bacteria releasing lipopolysaccharides (LPS), were assessed via 16S rRNA sequencing. miRNA sequencing on LPS-induced rat osteoblasts, with and without Oxymatrine, explored osteoblast proliferation, mineralization, and the miR-539-5p/OGN/Runx2 pathway.

RESULTS

The administration of OMT resulted in an enhancement of diabetic osteopathy by reversing trabecular bone loss and modifying the composition of gut microbiota, specifically affecting Gram-negative bacteria that release LPS into the bloodstream. miRNA sequencing revealed that miR-539-5p, which was upregulated in LPS-induced ROBs, was downregulated following OMT treatment. Furthermore, OMT was found to promote osteoblast proliferation and mineralization under conditions of LPS exposure and modulate the miR-539-5p/OGN/Runx2 signaling pathway.

CONCLUSIONS

OMT improves diabetic osteoporosis by altering gut microbiota, decreasing LPS release, and enhancing osteoblast growth and differentiation through the miR-539-5p/OGN/Runx2 pathway, suggesting its potential as a treatment.

TBBPA induced hepatocyte ferroptosis by PCBP1-mediated ferritinophagy

Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant and has been identified as emerging widespread pollutants. Ferroptosis, a recently characterized form of iron-dependent cell death, is related to a wide range of liver diseases. Ferritinophagy as a novel selective form of autophagy functions in iron processing is essential to induce ferroptosis. Poly(rC)-binding protein 1 (PCBP1) is an iron chaperone involved in iron loading to ferritin. Nevertheless, the potential health risk caused by TBBPA in mammals is unknown. Thus, this study is conducted to explore the molecular mechanism of TBBPA-induced liver injury and the unique role of PCBP1 in it. In this study, we found that TBBPA exposure caused hepatic pathological injury and hepatocyte mitochondrial morphological changes, such as decreased or absent mitochondrial crest, ruptured mitochondrial membranes and mitochondrial shrinkage. The result showed that TBBPA exposure exacerbated glutathione depletion and lipid peroxidation, which are hallmarks of ferroptosis. Consistent with the results in vivo, TBBPA exposure activated ferritinophagy and upregulated indicators related to ferroptosis in hepatocytes. Of note, overexpression of PCBP1 inhibited TBBPA-induced ferroptosis by reducing overstimulated ferritinophagy. Here, we uncover a new mechanism whereby TBBPA triggers hepatocyte ferroptosis through the activation of ferritinophagy. Of note, we identify PCBP1 as critical for liver iron homeostasis, link this molecule to liver disease. Taken together, our findings provide a new therapeutic strategy and potential target for the treatment of liver disease.

Different Forms of Regulated Cell Death in Type-2-Diabetes-Mellitus-Related Osteoporosis: A Focus on Mechanisms and Therapeutic Strategies

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder with a high prevalence and challenging treatment options. It significantly affects the function of various organs, including bones, and imposes substantial social and economic costs. Chronic hyperglycemia, insulin resistance, and abnormalities in glucolipid metabolism can lead to cellular damage within the body. Bone dysfunction represents a significant characteristic of diabetic osteoporosis (DOP). Recent studies confirm that cell death is a critical factor contributing to bone damage. Regulated cell death (RCD) is a highly controlled process that involves numerous proteins and specific signaling cascades. RCD processes, including apoptosis, autophagy, necroptosis, pyroptosis, ferroptosis, and cuproptosis, may be linked to the dysfunction of bone cells in T2DM. In this review, the cell death types of bone cell populations during the pathogenic process of DOP were explored, and the link between cellular RCD processes and the pathogenesis of DOP was further explored. In addition, the research progress on targeting RCD for DOP was summarized in this paper. This may provide a foundation for additional explorations and drug development, as well as new therapeutic concepts for the clinical management of DOP.

Dieckol ameliorates inflammatory response via inhibition of CHI3L1 expression in collagen-induced arthritis rats

BACKGROUND

Dieckol (DEK), the main phlorotannin of brown algal, has been regarded as a powerful anti-inflammatory agent in various diseases. Rheumatoid arthritis (RA) is a typical inflammatory autoimmune disease affecting synovial joints. However, the pharmaceutical effect of DEK on RA is still waiting to be unveiled.

METHODS

A collagen-induced arthritis (CIA) rat model was established and DEK was administered intraperitoneally for three weeks. Paw swelling and histologic analysis were performed to evaluate CIA progression. Inflammatory cytokine and oxidative biomarker expression were assessed by real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). Vascular endothelial growth factor A (VEGFA) expression in synovial joint was assessed by immunoblotting and immunofluorescent (IF) staining. TdT-mediated dUTP nick-end labeling (TUNEL) staining was used to evaluate chondrocyte apoptosis. Western blot assay was performed to determine the expression level of nuclear erythroid-derived 2-like 2 (Nrf2), chitinase 3-like protein 1(CHI3L1) and apoptosis-specific proteins. Finally, CHI3L1 overexpression was used to explore its essential role in the biological effect of DEK in vivo.

RESULTS

DEK treatment significantly ameliorates paw swelling, inflammatory cell infiltration, chondrocyte apoptosis and vascular pannus formation in CIA rats. Moreover, inflammatory cytokine and oxidative biomarker expression was also attenuated by DEK treatment. Notably, DEK treatment obviously promoted Nrf2 nuclear import and CHI3L1 expression in synovial joint. Overexpression of CHI3L1 by AVV-mediated transfection abrogated the pharmaceutical effect of DEK in vivo.

CONCLUSION

This study provides a promising translational potential of DEK as an anti-rheumatic drug facilitating RA clinical treatment.

Fullerol Initiates Stem Cell-Nanomaterials Interactions for Enhanced Tissue Regeneration via Clathrin-Mediated Endocytosis and Nuclear Factor Erythroid 2-Related Factor 2 Signaling

The advancement of nanomedicine requires a thorough understanding of the intrinsic bioactivity and molecular interactions of nanomaterials for safe and effective clinical applications, which remains lacking for most currently developed nanomaterials. Here, we uncover the unique intrinsic bioactivity and regulatory mechanisms of carbon-based fullerol nanomaterials through high-throughput molecular analysis and explore their therapeutic potential for tissue regeneration using tissue engineering approaches. Fullerol exhibits intrinsic pro-differentiation and antioxidant properties that enhance the osteogenesis and chondrogenesis of MSCs. Mechanistically, proteomic analysis combined with small-molecule inhibition studies reveals that fullerol is internalized by MSCs via clathrin-mediated endocytosis and activates NRF2 signaling, thereby exerting antioxidant effects that restore impaired MSC viability and differentiation under oxidative stress. Leveraging these unique bioactivities, we develop a fullerol-functionalized hydrogel with feasible physicochemical properties and triple biological functions in antioxidant, pro-osteogenic, and pro-chondrogenic effects and confirm its great regenerative capacity for both cartilage and subchondral bone by promoting structural restoration and improving functional recovery in a rat osteochondral defect model. Our findings offer new insights into the intricate interactions between stem cells and nanomaterials at the cellular and molecular levels and broaden the potential biomedical applications of fullerol for future cartilage and bone regeneration therapies.

Mechanistic insights into cadmium-induced nephrotoxicity: NRF2-Driven HO-1 activation promotes ferroptosis via iron overload and oxidative stress in vitro

Cadmium (Cd), a pervasive environmental toxicant, poses significant threats to human and animal health through multi-organ toxicity. While ferroptosis has been implicated in Cd-induced pathologies, the molecular mechanisms underlying Cd-mediated nephrotoxicity remain poorly understood. This study elucidates the ferroptosis pathway in CdCl2-exposed PK-15 cells and murine kidney, characterized by iron overload, lipid peroxidation, and mitochondrial dysfunction, which were ameliorated by ferroptosis inhibitor ferrostatin-1. Transcriptomic analysis revealed substantial upregulation of heme oxygenase-1 (HO-1) following CdCl2 exposure. Mechanistically, CdCl2 triggered nuclear translocation of nuclear factor erythroid 2-related factor-2 (NRF2), subsequently activating HO-1 transcription. Over-activated HO-1 catalyzes the decomposition of heme and releases free iron, accompanied with the degradation of ferritin heavy chain 1 (FTH1) induced by CdCl2 exposure, which leads to intracellular iron overload and excessive lipid peroxides production through Fenton reaction, resulting in ferroptosis ultimately. In vivo validation confirmed NRF2/HO-1-mediated ferroptosis in CdCl2-induced murine nephrotoxicity. Both pre-treatment with HO-1 competitive inhibitor Zinc protoporphyrin IX (ZnPP) and knockout of HO-1 gene remarkably alleviated PK-15 cells against ferroptosis induced by CdCl2 treatment. Our findings demonstrate that Cd exposure initiates NRF2-mediated HO-1 overexpression, driving iron-dependent lipid peroxidation and subsequent ferroptosis. This mechanistic insight provides potential therapeutic targets for mitigating Cd-induced renal damage, advancing our understanding of heavy metal toxicity and its cellular consequences.

Prevotella copri-mediated caffeine metabolism involves ferroptosis of osteoblasts in osteoarthritis

There is a positive causality between coffee consumption and osteoarthritis (OA); however, whether gut microbiota is involved needs to be discussed. Here, we observed that in caffeine consumers, fecal Prevotella copri abundance was positively correlated with subchondral bone mass, serum caffeine concentration was negatively correlated with bone mass, and fecal P. copri was negatively correlated with serum caffeine. In the OA model, caffeine intake aggravated articular cartilage destruction, bone mass loss, and intestinal barrier damage; on the contrary, paraxanthine intake reversed the above lesions. Importantly, after the intestinal P. copri supplement, caffeine-induced lesions in OA mice were effectively alleviated. Mechanically, P. copri has the potential to metabolize caffeine into paraxanthine, and this effect could alleviate the ferroptosis of osteoblast in the OA model. This study screened out that P. copri, an endogenous bacteria, has the ability to metabolize caffeine and revealed its effects on OA progression.IMPORTANCEThere is positive causality between coffee consumption and osteoarthritis (OA). Caffeine exposure is responsible for the reduction of bone mass and restrained osteoblast function. Prevotella copri abundance is exhausted in gut and positively correlated with subchondral bone mass in coffee consumption patients with OA. Supplement of intestinal P. copri alleviates caffeine-induced subchondral bone loss. P. copri has the potential to metabolize caffeine into paraxanthine, and this effect alleviates ferroptosis of osteoblast. Our study illustrated that intestinal P. copri possibly serves as a novel promising treatment for coffee consumers with OA.

Localized Intense Uptake in the Skull on 18F-Flortaucipir PET/CT

18F-Flortaucipir, as a classical Tau protein visualizer, has been widely used in the diagnosis of neurodegenerative diseases, especially Alzheimer disease. This report describes a case of intense uptake of 18F-Flortaucipir at 2 sites of reduced bone mineral density in the skull, but no radioactivity uptake was seen on 18F-FDG and 18F-Florbetapir PET/CT imaging at the same lesion sites. The mechanism behind 18F-Flortaucipir uptake in focal osteopenia remains unclear. This study provides evidence for the mechanism of the above phenomenon.

Inhibition of HMOX1 alleviates diabetic cardiomyopathy by targeting ferroptosis

Diabetic cardiomyopathy (DCM) is an important complication of chronic diabetes mellitus. However, its pathologic process and pathogenesis have not been fully elucidated. This study aims to investigate the role of ferroptosis in DCM and clarify the effect of heme oxygenase-1 (HMOX1) on DCM by targeting ferroptosis. In vivo, an animal model of DCM is established by subjecting mice to a high-fat diet (HFD) combined with low-dose streptozotocin (STZ) injection. We induce an in vitro DCM model by exposing H9C2 cells to high glucose and palmitic acid. Transcriptome sequencing reveals that the differentially expressed genes (DEGs) are enriched primarily in fatty acid metabolism and mitochondrial fatty acid β-oxidation, which are closely related to ferroptosis. The experimental results show that the diabetic microenvironment induces ferroptosis both in vivo and in vitro. Western blot analysis reveals the decreased expressions of the antioxidant proteins GPX4, SLC7A11 and ferritin in the DCM group. However, qPCR demonstrates the elevated expressions of the ferroptosis markers PTGS2 and ACSL4. Biochemical indicators further support the occurrence of ferroptosis, with increased levels of malondialdehyde (MDA) and lactate dehydrogenase (LDH), along with decreased level of glutathione (GSH). In vitro, intervention with high glucose and palmitic acid in H9C2 cells results in ferroptosis, which is reversed by ferrostatin-1 (Fer-1). Results show the elevated expression of HMOX1 in DCM. Moreover, knockdown of HMOX1 ameliorates ferroptosis, thereby alleviating diabetic cardiomyopathy by reducing cardiac fibrosis and improving cardiac function. Our study elucidates the role of HMXO1 in DCM pathogenesis and provides a potential therapeutic strategy for clinical treatment.

Evaluation of proanthocyanidins in treating Type 2 diabetic osteoporosis via SIRT6/Nrf2/GPX4 pathways

This study investigates the therapeutic potential of proanthocyanidins (PAC) in addressing Type 2 diabetic osteoporosis (T2DOP) by activating the SIRT6/Nrf2/GPX4 signaling pathways. T2DOP is characterized by compromised bone structure and heightened oxidative stress, where ferroptosis plays a pivotal role. Utilizing a T2DOP mouse model and MC3T3-E1 cells under high glucose conditions, we evaluated the impact of PAC on bone health and iron homeostasis. Our results, obtained through micro-CT, histological staining, Western blot, and immunofluorescence analyses, revealed reductions in bone density and decreased GPX4 expression in T2DOP conditions, indicating ferroptosis and oxidative stress. However, PAC treatment improved trabecular bone structure, reduced bone marrow adipocytes, decreased oxidative stress, and enhanced expression of key osteogenic proteins. These findings highlight PAC's potential in mitigating T2DOP through the SIRT6/Nrf2/GPX4 pathways, offering promising therapeutic insights for managing diabetic osteoporosis.

Protective effects of Tanshinone IIA preconditioning against hypobaric hypoxia-induced lung injury in a rat model

Tanshinone IIA (Tan-IIA), derived from Salvia miltiorrhiza, has been used in traditional Chinese medicine to treat cardiovascular diseases and pulmonary hypertension. This study investigates the potential of Tan-IIA preconditioning as a protective strategy against hypoxia-induced lung injury. Male Sprague-Dawley rats (200 ± 25 g) were divided into four groups: normoxia, normoxia with Tan-IIA, hypobaric hypoxia, and hypobaric hypoxia with Tan-IIA. Tan-IIA was administered intraperitoneally at doses of 10, 20, and 40 mg/kg body weight one hour before exposure to hypobaric hypoxia (simulated altitude of 25,000 feet for 48 h). Pulmonary edema was assessed by measuring transvacuolar leakage of sodium fluorescein dye and lung water content. Exposure to hypoxia triggered redox imbalances, inflammation, and changes in levels of nitric oxide (NOx), endothelin- 1, and Na/K ATPase, which contributed to pulmonary edema. Tan-IIA preconditioning, particularly at 20 mg/kg, was effective in reversing these disturbances. Tan-IIA modulated the expression of key signaling molecules, including c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38, as well as downstream activator protein- 1 (AP- 1) subunits (Jun and Fos), thus reducing inflammation. Its protective effects were partly due to increased NO levels and decreased endothelin, which lowered pulmonary vasoconstriction and permeability, respectively. Additionally, enhanced Na/K ATPase expression via hypoxia-inducible factor- 1 (HIF- 1) and AP- 1 pathways promoted alveolar fluid clearance, while interactions between nuclear factor erythroid 2-related factor 2 (Nrf2) and c-Jun highlighted the anti-oxidative properties of Tanshinone IIA. These findings demonstrate that Tanshinone IIA preconditioning protects against hypoxia-induced lung injury by mitigating pulmonary leakage. This highlights its potential therapeutic application in hypoxic lung conditions.

Bioinformatics-Based Analysis of Ferroptosis-Related Biomarkers and the Prediction of Drugs Affecting the Adipogenic Differentiation of MSCs

Background: The imbalance between the osteogenic and adipogenic differentiation of mesenchymal stem cells (MSCs) is a key factor in the progression of osteoporosis; therefore, it is crucial to study the regulatory mechanisms that maintain this balance. Ferroptosis is a form of regulated cell death caused by the accumulation of lipid peroxides and is closely associated with various diseases. Changes in intracellular oxidative stress levels can affect the lineage allocation of MSCs. However, it remains unclear whether the disruption of intracellular oxidative stress levels caused by ferroptosis can influence the osteogenic-adipogenic differentiation balance of MSCs, and the mechanism underlying this influence in osteoporosis has not been fully elucidated. This study is the first to demonstrate through in vitro cell experiments that inhibiting ferroptosis can decrease the adipogenic differentiation of MSCs. Methods and Results: Through bioinformatics analysis, differentially expressed genes (DEGs) associated with the adipogenic differentiation of MSCs were identified from the GEO database. We then intersected these differentially expressed genes with a ferroptosis-related gene dataset and identified 118 ferroptosis-related differentially expressed genes (FRDEGs). Additionally, we explored the functional roles of FRDEGs through GO and KEGG analyses and found that these genes significantly impacted intracellular oxidative stress. Furthermore, we identified 10 key FRDEGs via protein-protein interaction (PPI) analysis. The diagnostic performance of these genes was evaluated by plotting receiver operating characteristic (ROC) curves, and the reliability of the diagmodel was validated using data from osteoporosis patients. We then constructed a mouse osteoporosis model and validated the mRNA expression levels of key FRDEGs via qRT-PCR, which revealed significant differences in expression in the osteoporosis group. Finally, molecular docking technology was used to identify two small molecules from the DrugBank database that are able to negatively regulate MSC adipogenic differentiation by inhibiting ferroptosis. Conclusions: The identified FRDEGs and small molecules offer novel diagnostic markers and therapeutic candidates for osteoporosis.

An update on bone in diabetes

PURPOSE OF REVIEW

As the prevalence of diabetes mellitus (DM) increases due to urbanization, aging populations, and lifestyle changes, it is crucial to understand the mechanisms, diagnosis, and treatment of diabetes-related bone disorders. This review highlights recent advancements in the field and explores their implications for clinical practice and research.

RECENT FINDINGS

Recent studies have elucidated the complex interplay between diabetes and bone health, emphasizing the roles of advanced glycation end-products (AGEs), inflammation, oxidative stress, senescence, and molecular signaling pathways such as Wnt, mammalian target of rapamycin (mTOR), and exosome-mediated mechanisms. Key findings highlight the significance of bone marrow adipose tissue (BMAT) in bone metabolism and the impact of sarcopenia on fracture risk. Novel diagnostic tools, including miRNA biomarkers and emerging therapeutic strategies like exosome-based therapies and glycogen synthase kinase 3 beta (GSK3β) inhibitors, offer promising opportunities for improving bone health in diabetic patients.

SUMMARY

The findings underscore the need for integrated strategies for managing diabetes-related bone complications. Clinicians should prioritize early screening, lifestyle interventions, and personalized pharmacological treatments to mitigate fracture risk and improve bone health in diabetic patients. Future research should focus on optimizing diagnostic tools and developing targeted therapies to address the unique challenges of bone disorders related to diabetes.

Molecular mechanisms and targeted therapy of progranulin in metabolic diseases

Progranulin (PGRN) is a secreted glycoprotein with cytokine-like properties, exerting tripartite mechanisms of inflammation suppression, tissue repair promotion, and metabolic regulation. This multifaceted functionality positions PGRN as a potential "multi-effect therapeutic strategy" for metabolic disorders characterised by cartilage degradation and imbalanced bone remodelling, potentially establishing it as a novel therapeutic target for such conditions. Osteoarthritis, rheumatoid arthritis, intervertebral disc degeneration, osteoporosis, periodontitis, and diabetes-related complications-representing the most prevalent metabolic diseases-currently lack effective treatments due to incomplete understanding of their precise pathogenic mechanisms. Recent studies have revealed that PGRN expression levels are closely associated with the onset and progression of these metabolic disorders. However, the exact regulatory role of PGRN in these diseases remains elusive, partly owing to its tissue-specific actions and context-dependent dual roles (anti-inflammatory vs. pro-inflammatory). In this review, we summarise the structure and functions of PGRN, explore its involvement in neurological disorders, immune-inflammatory diseases, and metabolic conditions, and specifically focus on its molecular mechanisms in metabolic diseases. Furthermore, we consolidate advances in targeting PGRN and the application of its engineered derivative, Atsttrin, in metabolic bone disorders. We also discuss potential unexplored mechanisms through which PGRN may exert influence within this field or other therapeutic domains. Collectively, this work aims to provide a new framework for elucidating PGRN's role in disease pathogenesis and advancing strategies for the prevention and treatment of metabolic disorders.

The Role of Ferroptosis in Osteoporosis and Advances in Chinese Herbal Interventions

OP, a systemic bone disorder marked by reduced bone mass and heightened fracture risk, poses a significant global health burden, particularly among aging populations. Current treatments, including bisphosphonates and calcium supplementation, are limited by adverse effects and incomplete efficacy. Emerging research highlights ferroptosis-an iron-dependent cell death driven by lipid peroxidation-as a critical contributor to OP pathogenesis, characterized by dysregulated iron metabolism, oxidative stress, and lipid peroxide accumulation, which disrupt bone remodeling by impairing osteoblast function and enhancing osteoclast activity. This review elucidates the mechanistic interplay between ferroptosis and OP subtypes (diabetic osteoporosis (DOP), glucocorticoid-induced (GIOP), and postmenopausal osteoporosis (PMOP)) and evaluates the efficacy of Chinese herbal interventions in mitigating ferroptosis-driven bone loss. Key findings reveal that excess iron exacerbates lipid peroxidation via the Fenton reaction, while glutathione peroxidase 4 (GPX4) inactivation and system Xc- inhibition amplify oxidative damage. In DIOP, hyperglycemia-induced ROS and advanced glycation end products suppress osteogenesis, countered by melatonin and naringenin via nuclear factor -related factor 2 (Nrf2)/GPX4 activation. GIOP involves dexamethasone-mediated GPX4 downregulation, mitigated by exosomes and melatonin through phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling. PMOP driven by estrogen deficiency-induced iron overload is alleviated by aconitine and icariin (ICA) via nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and signal transducer and activator of transcription 3 (STAT3) pathways. Chinese herbs, including active compounds (quercetin, gastrodin, ICA, etc.) and formulations (Bugu Shengsui Capsule, Erxian Decoction (EXD), etc.), regulate iron metabolism, enhance antioxidant defenses (Nrf2/heme oxygenase 1(HO-1)), and inhibit lipid peroxidation, effectively restoring bone homeostasis. These findings underscore ferroptosis as a pivotal mechanism in OP progression and highlight the therapeutic promise of Chinese herbs in bridging traditional medicine with modern mechanistic insights. Future research should prioritize elucidating precise molecular targets, optimizing formulations, and validating clinical efficacy to address current therapeutic gaps.

Three-dimensional matrix stiffness-based stem cell soil: Tri-phase biomechanical structure promoted human dental pulp stem cells to achieve pulpodentin regeneration

The regeneration of the pulp-dentine complex is characterized by organizational diversity, with both dentine and pulp being essential for regenerating a complete tooth-like structure. Matrix stiffness plays a crucial role in guiding the multi-lineage differentiation of stem cells during the regeneration process. However, human dental pulp stem cell (HDPSCs) differentiation via three-dimensional (3D) matrix stiffness is still ambiguous. This study employed gelatin methacryloyl hydrogels of varying stiffness to investigate their effects on HDPSCs differentiation, and constructing a Tri-Phase Biomechanical Structure. The effects of 3D stiffness on HDPSCs proliferation, morphology, differentiation, and biomineralization were examined. The underlying mechanisms were analyzed by RNA sequencing (RNA-seq). At the same time, the comprehensive effects of 3D matrix stiffness-induced HDPSCs paracrine signals on periapical cells (endothelial cells, macrophages and fibroblasts) were evaluated. In vitro, high stiffness promoted dentin differentiation, medium stiffness supported vascular differentiation, and low stiffness enhanced vascularization of peri-apical cells through paracrine signals. In vivo, treated dentin matrixes implanted in nude mice further confirmed that this Tri-Phase Biomechanical Structure effectively promoted crownward dentin formation, pulp-like regeneration within root canals, and integration with periapical tissues. These findings highlight that understanding HDPSCs responses to 3D matrix stiffness is crucial for guiding targeted, efficient regeneration of a tooth-like pulpodentin complex.

The protection of nicotinamide riboside against diabetes mellitus-induced bone loss via OXPHOS

Diabetes mellitus is a global disease that results in various complications, including diabetic osteoporosis. Prior studies have indicated a correlation between low levels of nicotinamide adenine dinucleotide (NAD+) and diabetes-related complications. Nicotinamide riboside (NR), a widely utilized precursor vitamin of NAD+, has been demonstrated to enhance age-related osteoporosis through the Sirt1/FOXO/β-catenin pathway in osteoblast progenitors. However, the impact of NR on bone health in diabetes mellitus remains unclear. In this study, we assessed the potential effects of NR on bone in diabetic mice. NR was administered to high-fat diet (HFD)/streptozotocin (STZ)-induced type 2 diabetic mice (T2DM), and various parameters, including metabolic indicators, bone quality, bone metabolic markers, and RNA sequences, were measured. Our findings confirmed that HFD/STZ-induced T2DM impaired bone microstructures, resulting in bone loss. NR effectively ameliorated insulin resistance, improved bone microarchitecture, and bone quality, reduced bone resorption, enhanced the Forkhead box O (FOXO) signaling pathway, mitigated the nuclear factor kappa B (NF-kB) signaling pathway, and ameliorated the disorder of the oxidative phosphorylation process (OXPHOS) in diabetic mice. In conclusion, NR demonstrated the capacity to alleviate T2DM-induced bone loss through the modulation of OXPHOS in type 2 diabetic mice. Our results underscore the potential of NR as a therapeutic target for addressing T2DM-related bone metabolism and associated diseases. Further cell-based studies under diabetic conditions, such as in vitro cultures of key cell types (e.g., osteoblasts and osteoclasts), are necessary to validate these findings.

Scutellarin Alleviates Bone Marrow Mesenchymal Stromal Cellular Senescence via the Ezh2-Nrf2 Signalling Axis in Diabetes-Induced Bone Loss

Currently, there is no specific treatment for diabetes-induced osteoporosis (DOP). Our study identified diabetes-induced cellular senescence, marked by elevated activity of senescence-associated β-galactosidase. Targeting senescent cells holds promise for osteoporosis treatment. We demonstrated that scutellarin (SCU) effectively mitigated bone loss in DOP mice, and co-treatment with SCU significantly reduced diabetes-induced senescence in LepR+MSCs. Furthermore, our research highlighted the role of Nrf2 in SCU's anti-senescence effects on bone. The deletion of Nrf2 impaired SCU's ability to alleviate DOP. Mechanistically, SCU enhances Ezh2 expression and increases H3K27me3 activity at the Keap1 promoter region, leading to Keap1 repression and enhanced Nrf2-ARE signalling. Additionally, SCU notably inhibited cellular senescence and diabetes-related osteoporosis, these effects were significantly reduced in Ezh2LepRcre conditional knockout models. These findings suggest that the Ezh2-Nrf2 signalling axis is crucial for mediating SCU's beneficial effects in this context. Overall, our discoveries provide insights into the mechanisms underlying DOP and propose a potential preventive strategy for this condition.

Epimedium brevicornum Maxim alleviates diabetes osteoporosis by regulating AGE-RAGE signaling pathway

OBJECTIVES

Epimedium brevicornum Maxim (EP) has a history of utilization in Chinese traditional medicine for the treatment of bone diseases. However, the precise mechanism by which EP extract (EPE) operates in Diabetes osteoporosis (DOP) remains ambiguous. The study was aimed to explore the effects and underlying mechanisms of EPE on DOP, with particular emphasis on the AGE-RAGE pathway.

METHODS

The DOP model was induced through a combination of a high-sugar and high-fat diet along with streptozotocin injection. Following treatment with EPE, blood glucose levels, body weight, and serum biomarkers were measured. The trabecular microstructure of the femur was analyzed using micro-CT tomography and H&E staining. Bioinformatics techniques, including network pharmacology and molecular docking, were utilized to identify key targets of EP for DOP. The predicted targets and pathways were further validated through RT-PCR, TSA analysis ELISA, and western blotting (WB), respectively.

RESULTS

The findings from animal experiments indicate that EPE has a positive impact on weight and blood glucose levels, particularly in reversing the decrease and disordered arrangement of bone trabeculae. Bioinformatics analysis reveals the involvement of the AGE-RAGE pathways in the treatment of DOP with EPE. Subsequent animal validation experiments demonstrate that EPE can regulate key proteins AGE-RAGE pathway, resulting in reducing the inflammatory factors and apoptosis, including advanced Glycation End-products (RGEs), receptor for Advanced Glycation End-products (RAGE), Interleukin-6 (IL-6), Interleukin-1β (IL-1β), Nuclear Factor Kappa B (NF-κB), BCL2-Associated X protein (Bax), B-cell lymphoma 2(Bcl2), and etc. CONCLUSION: This study provides clear evidence that EPE mitigates DOP through enhancement of the AGE-RAGE pathways, offering innovative insights and approaches for clinical utilization.

Integrated Phenotypic and Transcriptomic Analyses of Osteoporosis in Type 2 Diabetic Mice

Background: Type 2 diabetes (T2D) is a global metabolic condition associated with complications of multiple organs, including the bone. However, the exact impact of T2D on bone along the disease progression, particularly in the early phase, remains largely unknown. Methods: Four-week and sixteen-week high-fat diet (HFD) feeding-induced T2D mouse models were established, and the glucose metabolic status was examined. Bone mass was evaluated by micro-computed tomography (micro-CT), and immunofluorescent (IF) staining was performed for bone histomorphometry with enzyme-linked immunosorbent assay (ELISA) determining serum markers. RNA sequencing analysis was performed to examine the transcriptome of bone, and single-cell RNA-sequencing (scRNA-seq) analysis was further applied. Bone marrow mesenchymal stem cells (BMMSCs) were isolated and analyzed for functional behaviors. Results: The occurrence of glucose metabolic disorders was confirmed at both four weeks and sixteen weeks of HFD feeding, showing increased blood glucose levels with impaired glucose tolerance and insulin sensitivity. Notably, early T2D osteoporosis symptoms were detected at four weeks, especially in the trabecular bone, demonstrating reduced bone mass and mineral density. Histological analysis confirmed that bone remodeling and immune-related inflammation were also altered in T2D mice, remarkably at the early phase, mainly reflected by suppressed bone formation, stimulated bone resorption, increased macrophages, and elevated tumor necrosis factor-alpha (TNF-α) levels. Transcriptomic sequencing further demonstrated significant yet distinct changes in the gene expression profile of bone during T2D progression, which confirmed the histological findings. Notably, overlapping genes with altered expression at four weeks and sixteen weeks of T2D compared to the respective control were identified, and bone marrow scRNA-seq analysis indicated many of them were expressed in BMMSCs, suggesting BMMSCs critically involved in T2D osteoporosis. Dysregulated molecular profiles and functional abnormalities of BMMSCs in T2D mice were validated by ex vivo assays, showing early and persistent occurrence of impaired colony-forming and proliferative capacities with biased differentiation potential. Conclusions: These findings elucidate the bone lesion phenotype in T2D, particularly at the early phase, uncover changes in gene expression profiles of bone during T2D progression, and clarify the functional alterations in bone stem cells, providing a basis for subsequent research and the development of treatment strategies.

Lysyl oxidase nanozyme-loaded hydrogel for sustained release and promotion of diabetic bone defect regeneration

The process of regenerating bone injuries in diabetic presents significant challenges because lysine oxidase (LOX), a key catalytic enzyme for collagen cross-linking, is inhibited in hyperglycemia. The supplementation of LOX is constrained by inadequate sources and diminished enzymatic activity, necessitating the development of effective alternatives for enhancing bone regeneration in diabetes. Herein, we reported a lysyl oxidase nanozyme (LON), derived from the catalytic domain of LOX. LON formed a stable coordination structure with the active center Cu2+ through histidine imidazolyl nitrogen and quinone oxygen, which is consistent with the conformation of the LOX. Our findings suggested that LON demonstrated the capacity to substitute LOX in promoting collagen synthesis and biomineralization. To enable sustained LON delivery, it was incorporated into a GelMA hydrogel (GH), forming a sustained-release reservoir known as LON-GelMA hydrogel (LONGH). Mechanism of LONGH promoting bone healing to accelerate the crosslinking and maturation stage of collagen were also explored, and the 23 genes closely associated with collagen regeneration and osteogenesis were found to be upregulated. The present investigation outcomes reveal that the engineered LONGH hydrogel presents a novel, simple, and commercially viable approach for bone regeneration, offering significant potential for clinical applications.

BMP9 alleviates iron accumulation-induced osteoporosis via the USP10/FOXO1/GPX4 axis

INTRODUCTION

Ferroptosis induced by iron accumulation can disrupt the physiological functions of bone marrow mesenchymal stem cells (BMSCs). BMP9 is an effective osteogenic factor. However, the role of BMP9 and its molecular mechanisms in osteoporosis induced by iron accumulation remain unclear.

OBJECTIVES

This study aims to explore the role and mechanism of BMP9 in alleviating iron accumulation induced osteoporosis.

METHODS

Clinical samples were collected to analyze the relationship between iron accumulation and osteoporosis. The effect of BMP9 on lipid peroxidation levels in BMSCs under iron accumulation conditions was assessed using C11-BODIPY staining, MitoSOX staining, MDA and SOD activity measurement. The osteogenic capacity of BMP9 in BMSCs under iron accumulation conditions was evaluated by measuring ALP activity and calcium nodule formation. The mechanisms of BMP9 in regulating BMSCs under iron accumulation conditions were explored through experiments including cycloheximide treatment, RT-PCR, Western blot, GST pull-down, ChIP, and CO-IP.

RESULTS

It was observed in human samples that serum ferritin levels were negatively correlated with the bone mineral density of the lumbar spine and femoral neck. Meanwhile, ferroptosis is considered a key factor affecting bone health. Further research indicated that BMP9 could inhibit ferroptosis in cells and animal models with iron accumulation, while also improving oxidative stress and osteogenic capacity. In-depth investigation of its mechanism reveals that BMP9 promotes the expression of USP10, which removes the K48-linked ubiquitin chains on FOXO1, inhibiting its excessive ubiquitination in the cytoplasm. This stabilization allows FOXO1 to accumulate in the cytoplasm and eventually re-enter the nucleus. This process activated the expression of the key inhibitor of cell death, GPX4, enhancing the cell's antioxidant response, reducing ferroptosis-induced damage to BMSCs, and promoting their osteogenic differentiation.

CONCLUSION

This study reveals that BMP9 inhibits ferroptosis through the USP10/FOXO1/GPX4 axis, providing a new therapeutic strategy for osteoporosis caused by iron accumulation.

Transcriptomic analysis revealed ferroptosis in ducklings with splenic necrosis induced by NDRV infection

Infection with novel duck reovirus (NDRV) results in severe splenic necrosis, leading to immunosuppression, secondary infections with other pathogens, and impairment of the immune effect of the vaccine. However, little is known about NDRV-induced spleen injury and its antagonistic mechanism on the host immune response. In this study, we conducted pathological and comparative transcriptomic analyses of NDRV-infected duck spleens. Our findings elucidated the histopathological progression of splenic necrotic foci formation following NDRV infection and identified splenic macrophages as the primary target cells. RNA-Seq analysis revealed differentially expressed genes that were enriched predominantly in immune system processes, signalling molecules and interactions, and pathways related to cell growth and necrosis. Notably, we observed a significant upregulation of ferroptosis during NDRV infection, characterized by the induction of specific metabolism-related genes such as TfR1, Hmox1, and STEAP3, alongside the downregulation of Fpn expression. Our findings collectively indicate the involvement of ferroptosis in spleen injury induced by NDRV infection. Investigating the mechanism of NDRV-induced ferroptosis in spleen macrophages will contribute to a comprehensive understanding of the pathogenesis associated with NDRV.

The role of programmed cell death in diabetes mellitus-induced erectile dysfunction: from mechanisms to targeted therapy

Diabetes mellitus (DM) is a chronic metabolic disease that often leads to vascular endothelial injury and peripheral neuropathy. Erectile dysfunction (ED), a common condition in andrology, is frequently associated with DM. The incidence of diabetes mellitus-induced ED (DMED) is second only to the cardiovascular complications of diabetes. Compared to other types of ED, DMED presents with more severe symptoms, rapid progression, and notable resistance to phosphodiesterase type 5 inhibitors (PDE5is). Various forms of programmed cell death (PCD)-including apoptosis, autophagy, pyroptosis, and ferroptosis-play pivotal roles in the pathogenesis of DMED. An exacerbation of DMED is linked to critical irritants like advanced glycation end-products (AGEs) and reactive oxygen species (ROS) in the corpus cavernosum tissue. These irritants can spark anomalous activations of diverse PCDs, which damage primary corpus cavernosum cells like cavernous nerve cells, endothelial cells, and myocytes, leading to ED. Hence, we reviewed current knowledge on the mechanisms and therapeutic potential of targeting PCDs in DMED, aiming to advance strategies for enhancing erectile function.

Enhanced SIRT3 expression restores mitochondrial quality control mechanism to reverse osteogenic impairment in type 2 diabetes mellitus

Osteoporosis represents a prevalent and debilitating comorbidity in patients diagnosed with type 2 diabetes mellitus (T2DM), which is characterized by suppressed osteoblast function and disrupted bone microarchitecture. In this study, we utilized male C57BL/6 J mice to investigate the role of SIRT3 in T2DM. Decreased SIRT3 expression and impaired mitochondrial quality control mechanism are observed in both in vitro and in vivo models of T2DM. Mechanistically, SIRT3 suppression results in hyperacetylation of FOXO3, hindering the activation of the PINK1/PRKN mediated mitophagy pathway and resulting in accumulation of dysfunctional mitochondria. Genetical overexpression or pharmacological activation of SIRT3 restores deacetylation status of FOXO3, thus facilitating mitophagy and ameliorating osteogenic impairment in T2DM. Collectively, our findings highlight the fundamental regulatory function of SIRT3 in mitochondrial quality control, crucial for maintaining bone homeostasis in T2DM. These insights not only enhance our understanding of the molecular mechanisms underlying diabetic osteoporosis but also identify SIRT3 as a promising therapeutic target for diabetic osteoporosis.

Methyltransferase-like 3 mediates m6A modification of heme oxygenase 1 mRNA to induce ferroptosis of renal tubular epithelial cells in acute kidney injury

Acute kidney injury (AKI) involves a series of syndromes characterized by a rapid increase in creatinine levels. Ferroptosis, as an iron-dependent mode of programmed cell death, reportedly participates in the pathogenesis of AKI. Methyltransferase-like 3 (METTL3)-mediated N6-methyladenosine (m6A) modification has been recently associated with various kidney diseases; however, the mechanism of METTL3 crosstalk with the molecules involved in ferroptosis is not clearly understood. Here, we investigated the crosstalk between METTL3-mediated m6A modification and ferroptosis in AKI. METTL3-mediated m6A modification was elevated in patients with AKI, folic acid-AKI mice, and tert-butyl hydrogen peroxide-stimulated TCMK-1 cells. Inhibition of METTL3 expression in vivo and in vitro alleviated the damage and ferroptosis in renal tubular cells. Methylated RNA immunoprecipitation sequencing showed that heme oxygenase 1 (Hmox1/HO-1) was the METTL3 target. RNA immunoprecipitation-qPCR indicated that anti-insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) could be used as a reader to bind to the methylated site of Hmox1 mRNA to maintain its stability. Hmox1 knockdown in vitro reduced the accumulation of iron ions and alleviated ferroptosis. METTL3 mediates the m6A modification of Hmox1 mRNA and maintains its stability in an IGF2BP3-dependent manner, which causes iron overload in renal tubular epithelial cells, leading to ferroptosis and AKI.

Mechanisms of Ferroptosis in bone disease: A new target for osteoporosis treatment

Osteoporosis (OP) is a common disease in the elderly, characterized by decreased bone strength, reduced bone density, and increased fracture risk. There are two clinical types of osteoporosis: primary osteoporosis and secondary osteoporosis. The most common form is postmenopausal osteoporosis, which is caused by decreased estrogen production after menopause. Secondary osteoporosis, on the other hand, occurs when certain medications, diabetes, or nutritional deficiencies lead to a decrease in bone density. Ferroptosis, a new iron-dependent programmed cell death process, is critical in regulating the development of osteoporosis, but the underlying molecular mechanisms are complex. In the pathologic process of osteoporosis, several studies have found that ferroptosis may occur in osteocytes, osteoblasts, and osteoclasts, cell types closely related to bone metabolism. The imbalance of iron homeostasis in osteoblasts and excessive iron accumulation can promote lipid peroxidation through the Fenton reaction, which induces ferroptosis in osteoblasts and affects their role in regulating bone metabolism. Ferroptosis in osteoblasts inhibits bone formation and reduces the amount of new bone production. Osteoclast-associated ferroptosis abnormalities, on the other hand, may alter the homeostasis of bone resorption. In this paper, we start from the molecular mechanism of ferroptosis, and introduce the ways in which ferroptosis affects the physiological and pathological processes of the body. After that, the effects of ferroptosis on osteoblasts and osteoclasts will be discussed separately to elucidate the molecular mechanism between ferroptosis and osteoporosis, which will provide a new breakthrough for the prevention and treatment of osteoporosis and a more effective and better idea for the treatment strategy of osteoporosis.

Sympathetic innervation induces exosomal miR-125 transfer from osteoarthritic chondrocytes, disrupting subchondral bone homeostasis and aggravating cartilage damage in aging mice

INTRODUCTION

Osteoarthritis (OA) is a progressive disease that poses a significant threat to human health, particularly in aging individuals: Although sympathetic activation has been implicated in bone metabolism, its role in the development of OA related to aging remains poorly understood. Therefore, this study aimed to investigate how sympathetic regulation impacts aging-related OA through experiments conducted both in vivo and in vitro.

METHODS

To analyze the effect of sympathetic regulation on aging-related OA, we conducted experiments using various mouse models. These models included a natural aging model, a medial meniscus instability model, and a load-induced model, which were used to examine the involvement of sympathetic nerves. In order to evaluate the expression levels of β1-adrenergic receptor (Adrβ1) and sirtuin-6 (Sirt6) in chondrocytes of naturally aging OA mouse models, we performed assessments. Additionally, we investigated the influence of β1-adrenergic receptor knockout or treatment with a β1-adrenergic receptor blocker on the progression of OA in aging mice and detected exosome release and detected downstream signaling expression by inhibiting exosome release. Furthermore, we explored the impact of sympathetic depletion through tyrosine hydroxylase (TH) on OA progression in aging mice. Moreover, we studied the effects of norepinephrine(NE)-induced activation of the β1-adrenergic receptor signaling pathway on the release of exosomes and miR-125 from chondrocytes, subsequently affecting osteoblast differentiation in subchondral bone.

RESULTS

Our findings demonstrated a significant increase in sympathetic activity, such as NE levels, in various mouse models of OA including natural aging, medial meniscus instability, and load-induced models. Notably, we observed alterations in the expression levels of β1-adrenergic receptor and Sirt6 in chondrocytes in OA mouse models associated with natural aging, leading to an improvement in the progression of OA. Critically, we found that the knockout of β1-adrenergic receptor or treatment with a β1-adrenergic receptor blocker attenuated OA progression in aging mice and the degraded cartilage explants produced more exosome than the nondegraded ones, Moreover, sympathetic depletion through TH was shown to ameliorate OA progression in aging mice. Additionally, we discovered that NE-induced activation of the β1-adrenergic receptor signaling pathway facilitated the release of exosomes and miR-125 from chondrocytes, promoting osteoblast differentiation in subchondral bone.

CONCLUSION

In conclusion, our study highlights the role of sympathetic innervation in facilitating the transfer of exosomal miR-125 from osteoarthritic chondrocytes, ultimately disrupting subchondral bone homeostasis and exacerbating cartilage damage in aging mice. These findings provide valuable insights into the potential contribution of sympathetic regulation to the pathogenesis of aging-related OA.

Targeting PTGDS Promotes ferroptosis in peripheral T cell lymphoma through regulating HMOX1-mediated iron metabolism

BACKGROUND

Peripheral T cell lymphoma (PTCL) is characterized by high heterogeneity, strong aggressiveness, and extremely poor prognosis. Ferroptosis, a novel form of programmed cell death, has been involved in tumor development and targeting ferroptosis holds great potential for tumor therapy.

METHODS

Lentiviral transfection was performed to regulate gene expression, followed by Tandem mass tag (TMT)-mass spectrometry and RNA-sequencing. Tumor xenograft models were established for in vivo experiments.

RESULTS

High expression of prostaglandin D2 synthase (PTGDS) was closely associated with poor prognosis of PTCL patients. PTGDS knockdown and AT56 treatment significantly inhibited the progression of PTCL through regulating cell viability, proliferation, apoptosis, cell cycle and invasion in vitro and in vivo. We further revealed that targeting PTGDS promoted ferroptosis process and enhanced the sensitivity of PTCL cells to ferroptosis inducers Sorafenib in vitro and in vivo. Mechanically, PTGDS interacted with heme-degrading enzymes HMOX1, and targeting PTGDS increased the level of iron and induced ferroptosis in PTCL through promoting HMOX1-mediated heme catabolism and ferritin autophagy process. Through the construction of H25A mutation, the specific gene site of HMOX1 corresponding to its role was identified.

CONCLUSIONS

Taken together, our findings firstly identified that targeting PTGDS promotes the ferroptosis in PTCL through regulating HMOX1-mediated iron metabolism, and highlighted novel therapeutic strategies to improve the efficacy of ferroptosis-targeted therapy in PTCL patients.

Targeted Management of Diabetic Osteoporosis by Biocatalytic Cascade Reaction Nanoplatform

Diabetic osteoporosis (DOP) is a chronic complication of diabetes mellitus (DM) that impairs bone health, and effective management of DOP remains a formidable challenge. In this study, we developed a biocatalytic cascade nanoplatform, GOx@SrCaP-CAT-Tet, offering osteogenic, angiogenic, and anti-inflammatory activities for targeted DOP management. The platform includes glucose oxidase (GOx) and catalase (CAT), encapsulated in strontium-doped calcium phosphate (SrCaP), converting glucose into gluconic acid and hydrogen peroxide (H2O2), alleviating the hyperglycemia and promoting hypoxia-induced vascularization. Both the generated H2O2 and any overabundance of H2O2 in the DOP microenvironment can be scavenged by CAT, thus relieving inflammation. Via a surface modified with tetracycline (Tet) for bone targeting, the release of Sr2+, Ca2+, and PO43- can stimulate osteogenesis and suppress osteoclastogenesis, thereby hastening bone formation and reversing osteoporosis. This nanoplatform shows promise in managing DOP both in vitro and in vivo. Our findings open a new horizon for managing DOP through biocatalytic cascade reactions.

Ferroptosis in senescence and age-related diseases: pathogenic mechanisms and potential intervention targets

As the global population continues to age, the prevalence of age-related diseases is increasing, significantly influencing social and economic development, the stability of social security systems, and progress in medical technology. Ferroptosis, a recently discovered form of programmed cell death driven by iron-dependent lipid peroxidation, has emerged as a key area of research. Studies have revealed a strong association between ferroptosis and senescence. In this article, we systematically summarize the molecular mechanisms and associated signaling pathways underlying ferroptosis, emphasizing its pivotal role in the onset and progression of age-related diseases. By providing new perspectives, we aim to advance understanding of the pathogenesis of age-related diseases and guide the development of effective intervention strategies.

The Gut Microbiota Metabolite Butyrate Modulates Acute Stress-Induced Ferroptosis in the Prefrontal Cortex via the Gut-Brain Axis

Stress has been implicated in the onset of mental disorders such as depression, with the prefrontal cortex (PFC) playing a crucial role. However, the underlying mechanisms remain to be fully elucidated. Metabolites secreted by intestinal flora can enter the bloodstream and exert regulatory effects on the body. Consequently, this study aims to investigate the molecular mechanisms by which gut flora influences ferroptosis in PFC neurons, thereby affecting depression-like behavioral changes in mice subjected to acute stress. Initially, we established a mouse model of acute restraint stress (3-day duration) and verified that stress-induced ferroptosis of PFC neurons contributed to depression-like behavioral alterations in mice, as evidenced by morphological, behavioral, and molecular biology assessments. Subsequently, through fecal microbiota transplantation (FMT) experiments, we established a significant correlation between gut microbiota and ferroptosis of PFC neurons in acute stress-exposed mice. 16S rDNA sequencing identified butyric acid-producing bacteria, specifically g_Butyricimonas and its primary metabolite, butyric acid, as critical regulators of ferroptosis in PFC neurons in acutely stressed mice. Furthermore, the intervention of butyrate demonstrated its potential to ameliorate damage to the intestinal and blood-brain barriers in these mice. This intervention also mitigated depression-like behaviors induced by ferroptosis of PFC neurons by alleviating systemic inflammatory responses. The findings of this study indicate that acute stress-induced ferroptosis of PFC neurons plays a critical role in depression-like behavioral changes in mice. Additionally, the gut microbiota metabolite butyrate can modulate ferroptosis and depression-like behavioral changes through the gut-brain axis.

Investigating the molecular mechanisms of Jiangu Decoction in treating type 2 diabetic osteoporosis

ETHNOPHARMACOLOGICAL RELEVANCE

Type 2 diabetic osteoporosis (T2DOP) is a metabolic bone disease characterized by impaired bone structure and decreased bone strength in diabetic patients. Jiangu Decoction (JGD), a traditional Chinese poly-herbal formulation, has shown efficacy in mitigating osteoporosis (OP) and fractures caused by osteoporosis in diabetic patients in clinical trials. In addition, JGD has been proven to promote the proliferation of osteoblasts. However, the specific mechanisms underlying these effects remain unclear.

AIM OF THE STUDY

This study aimed to elucidate the molecular mechanisms underlying the therapeutic effects of JGD in treating T2DOP.

MATERIALS AND METHODS

Liquid chromatography-mass spectrometry (LC-MS) was utilized to elucidate the chemical profile of JGD. A T2DOP mouse model (C57BL/6) was established by combining a high-fat diet with streptozotocin (STZ). Micro-computed tomography (micro-CT) imaging, three-point bending tests, and histological staining were utilized to assess alterations in bone mass, bone quality, and bone strength in mice. Mouse Calvaria 3T3-E1 (MC3T3-E1) cells were treated with 33 mmol/L D-glucose (HG), and the protective effect of JGD on the high glucose injury model was observed. Western blotting and qRT-PCR were employed to analyze alterations in biomarkers associated with the Keap1/Nrf2/HO-1 signaling pathway, both in vivo and in vitro.

RESULTS

A total of 909 compounds were identified in JGD using LC-MS. Subsequently, the function of JGD was evaluated both in vitro and in vivo. The findings indicated that JGD promoted bone formation, enhanced bone microstructure, and ameliorated diabetic symptoms in T2DOP mice. Additionally, JGD increased alkaline phosphatase (ALP) activity, facilitated bone mineralization, and upregulated the expression levels of osteogenic marker genes such as runt-related transcription factor 2 (Runx2), osteocalcin (Ocn), and collagen type 1 alpha (Col1a1). Importantly, JGD reduced oxidative stress levels and decreased the accumulation of reactive oxygen species by modulating the Keap1/Nrf2/HO-1 axis both in vivo and in vitro.

CONCLUSION

Our study suggests that JGD could alleviate T2DOP impairment, closely linked to the Keap1/Nrf2/HO-1 signaling pathway.

The application of procyanidins in diabetes and its complications: a review of preclinical studies

Diabetes mellitus (DM) and its various complications, including diabetic nephropathy, retinopathy, neuropathy, cardiovascular disease, and ulcers, pose significant challenges to global health. This review investigates the potential of procyanidins (PCs), a natural polyphenolic compound, in preventing and managing diabetes and its complications. PCs, recognized for their strong antioxidant, anti-inflammatory, and anti-hyperglycemic properties, play a crucial role in reducing oxidative stress and enhancing endothelial function, which are essential for managing diabetic complications. This review elucidates the molecular mechanisms by which PCs improve insulin sensitivity and endothelial health, thereby providing protection against the various complications of diabetes. The comprehensive analysis underscores the promising therapeutic role of PCs in diabetes care, indicating the need for further clinical studies to confirm and leverage their potential in comprehensive diabetes management strategies.

Fraxinellone-mediated targeting of cathepsin B leakage from lysosomes induces ferroptosis in fibroblasts to inhibit hypertrophic scar formation

BACKGROUND

Hypertrophic scar (HS) is a common fibrotic skin disorder characterized by the excessive deposition of extracellular matrix (ECM). Fibroblasts are the most important effector cells involved in HS formation. Currently no satisfactory treatment has been developed.

METHODS

The impact of fraxinellone (FRA) on the proliferation and migration capacity of human hypertrophic scar-derived fibroblasts (HSFs) was assessed by EdU proliferation, wound healing and transwell assays. Quantitative real-time PCR (qRT‒PCR), Western blot (WB), immunofluorescence staining and collagen gel contraction assays were performed to evaluate the collagen production and activation capacity of HSFs. Oxford Nanopore Technologies long-read RNA sequencing (ONT long-read RNA-seq) revealed the occurrence of ferroptosis in HSF and ferroptosis executioner-cathepsin B (CTSB). The mechanisms underlying FRA-induced HSF ferroptosis were examined through fluorescence staining, qRT‒PCR, WB and molecular docking study. The therapeutic efficacy of FRA was further validated in vivo using a rabbit ear scar model.

RESULTS

FRA treatment significantly suppressed the proliferation, migration, collagen production and activation capacity of HSFs. ONT long-read RNA-seq discovered that FRA modulated the expression of transcripts related to ferroptosis and lysosomes. Mechanistically, FRA treatment reduced the protein expression level of glutathione peroxidase 4 (GPX4) and induced the release of CTSB from lysosomes into the cytoplasm. CTSB further induced ferroptosis via spermidine/spermine-N1-acetyltransferase (SAT1)-mediated lipid peroxidation, mitochondrial damage and mitogen-activated protein kinase (MAPK) signalling pathway activation, eventually affecting the function of HSFs. Moreover, FRA treatment attenuated the formation of HS in rabbit ears via CTSB-mediated ferroptosis. The antifibrotic effects of FRA were abrogated by pretreatment with a CTSB inhibitor (CA-074-me).

CONCLUSIONS

This study reveals that FRA ameliorates HS by inducing CTSB leakage from lysosomes, causing SAT1-mediated lipid peroxidation, mitochondrial damage and MAPK signalling pathway activation, thus mediating HSF ferroptosis. Therefore, FRA could be a promising therapeutic agent for treating HS.

Ameliorating macrophage pyroptosis via ANXA1/NLRP3/Caspase-1/GSDMD pathway: Ac2-26/OGP-loaded intelligent hydrogel enhances bone healing in diabetic periodontitis

Craniofacial bone defect healing in periodontitis patients with diabetes background has long been difficult due to increased blood glucose levels which cause overproduction of reactive oxygen species (ROS) and a low pH environment. These conditions negatively affect the function of macrophages, worsen inflammation and oxidative stress, and ultimately, hinder osteoblasts' bone repair potential. In this study, we for the first time found that annexin A1 (ANXA1) expression in macrophages was reduced in a diabetic periodontitis (DP) environment, with the activation of the NLRP3/Caspase-1/GSDMD signaling pathway, and, eventually, increased macrophage pyroptosis. Next, we have developed a new GPPG intelligent hydrogel system which was ROS and pH responsive, and loaded with Ac2-26, an ANXA1 bioactive peptide, and osteogenic peptide OGP as well. We found that Ac2-26/OGP/GPPG can effectively reduce ROS, mitigates macrophage pyroptosis via the ANXA1/NLRP3/Caspase-1/GSDMD pathway and enhanced osteogenic differentiation. The effect of Ac2-26/OGP/GPPG in regulation of pyroptosis and bone defect repair was also further validated by animal experiments on periodontitis-induced tooth loss model in diabetic rats. To conclude, our study unveils the effect of ANXA1 on macrophage pyroptosis in periodontitis patients with diabetes, based on which we introduced a promising innovative hydrogel system for improvement of bone defects repair in DP patients via targeting macrophage pyroptosis and enhancing osteogenic potential.

Correlation Between Blood Glucose Fluctuations and Osteoporosis in Type 2 Diabetes Mellitus

The purpose of this review is to investigate the impacts of blood glucose fluctuations on diabetic osteoporosis, a complication of Type 2 diabetes mellitus (T2DM) that remains poorly understood. We reviewed the current evidence of the relationship between blood glucose fluctuations and diabetic osteoporosis in patients with T2DM. The findings indicate that blood glucose fluctuations may contribute to inhibiting the processes of bone formation and resorption, promoting diabetic osteoporosis and fractures in T2DM. Mechanistic studies, both in vitro and in vivo, reveal that these effects are largely mediated by oxidative stress, advanced glycation end products, inflammatory mediators, and multiple pathways inducing cell apoptosis or autophagy. Thus, maintaining the long-term stability of blood glucose levels emerges as a target to be pursued in clinical practice in order to safely reduce mean blood glucose and for its direct effects on osteoporosis and fractures in T2DM.

Regulation of enzymatic lipid peroxidation in osteoblasts protects against postmenopausal osteoporosis

Oxidative stress plays a critical role in postmenopausal osteoporosis, yet its impact on osteoblasts remains underexplored, limiting therapeutic advances. Our study identifies phospholipid peroxidation in osteoblasts as a key feature of postmenopausal osteoporosis. Estrogen regulates the transcription of glutathione peroxidase 4 (GPX4), an enzyme crucial for reducing phospholipid peroxides in osteoblasts. The deficiency of estrogen reduces GPX4 expression and increases phospholipid peroxidation in osteoblasts. Inhibition or knockout of GPX4 impairs osteoblastogenesis, while the elimination of phospholipid peroxides rescues bone formation and mitigates osteoporosis. Mechanistically, 4-hydroxynonenal, an end-product of phospholipid peroxidation, binds to integrin-linked kinase and triggers its protein degradation, disrupting RUNX2 signaling and inhibiting osteoblastogenesis. Importantly, we identified two natural allosteric activators of GPX4, 6- and 8-Gingerols, which promote osteoblastogenesis and demonstrate anti-osteoporotic effects. Our findings highlight the detrimental role of phospholipid peroxidation in osteoblastogenesis and underscore GPX4 as a promising therapeutic target for osteoporosis treatment.

Melanoma bone metastasis-induced osteocyte ferroptosis via the HIF1α-HMOX1 axis

Osteocytes are the main cells in mineralized bone tissue. Elevated osteocyte apoptosis has been observed in lytic bone lesions of patients with multiple myeloma. However, their precise contribution to bone metastasis remains unclear. Here, we investigated the pathogenic mechanisms driving melanoma-induced osteocyte death. Both in vivo models and in vitro assays were combined with untargeted RNA sequencing approaches to explore the pathways governing melanoma-induced osteocyte death. We could show that ferroptosis is the primary mechanism behind osteocyte death in the context of melanoma bone metastasis. HMOX1 was identified as a crucial regulatory factor in this process, directly involved in inducing ferroptosis and affecting osteocyte viability. We uncover a non-canonical pathway that involves excessive autophagy-mediated ferritin degradation, highlighting the complex relationship between autophagy and ferroptosis in melanoma-induced osteocyte death. In addition, HIF1α pathway was shown as an upstream regulator, providing a potential target for modulating HMOX1 expression and influencing autophagy-dependent ferroptosis. In conclusion, our study provides insight into the pathogenic mechanisms of osteocyte death induced by melanoma bone metastasis, with a specific focus on ferroptosis and its regulation. This would enhance our comprehension of melanoma-induced osteocyte death.

Therapeutic Potential of Targeting Ferroptosis in Periprosthetic Osteolysis Induced by Ultra-High-Molecular-Weight Polyethylene Wear Debris

Background/Objectives: Periprosthetic osteolysis is the primary cause of arthroplasty failure in the majority of patients. Mechanistically, wear debris released from the articulating surfaces of a prosthesis initiates local inflammation and several modes of regulated cell death programs, such as ferroptosis, which represents a promising therapeutic target in various chronic inflammatory diseases. Thus, the current study aimed at exploring the therapeutic potential of targeting ferroptosis in a polyethylene-wear-debris-induced osteolysis model. Methods: Inverted cell culture model was used for stimulating the cells with wear debris in vitro, and calvarial osteolysis model was used for evaluating the therapeutic effects of inhibitors in vivo. Results: The immunostaining of periprosthetic bone tissues demonstrated a number of osteocytes expressing ferroptosis markers. Likewise, the expressions of ferroptosis markers were confirmed in polyethylene-wear-debris-stimulated osteocyte-like cells and primary osteoblasts in a direct stimulation model but not in an indirect stimulation model. Furthermore, polyethylene wear debris was implanted onto calvarial bone and mice were treated with the ferroptosis inhibitors DFO and Fer-1. These treatments alleviated the inflammatory and pathological bone resorption induced by the wear debris implantation. Conclusions: Our data broaden the knowledge of the pathogenesis of periprosthetic osteolysis and highlight ferroptosis as a promising therapeutic target.

MMP-9 responsive hydrogel promotes diabetic wound healing by suppressing ferroptosis of endothelial cells

Ferroptosis plays a crucial role in the progression of diabetic wounds, suggesting potential therapeutic strategies to target ferroptosis. Transient receptor potential ankyrin 1 (TRPA1) is a non-selective calcium channel that acts as a receptor for a variety of physical or chemical stimuli. Cinnamaldehyde (CA) is a specific TRPA1 agonist. In in vitro experiments, we observed that high glucose (HG) treatment induced endothelial cell ferroptosis, impairing cell function. CA successfully inhibited endothelial cell ferroptosis, improving migration, proliferation, and tube formation. Further mechanistic studies showed that CA-activated TRPA1-induced Ca2+ influx promoted the phosphorylation of calmodulin-dependent protein kinase II (CaMKII) and nuclear factor-E 2-related factor 2 (Nrf2) translocation, which contributed to the elevation of glutathione peroxidase 4 (GPX4), leading to the inhibition of endothelial cell ferroptosis. In addition, CA was incorporated into an MMP-9-responsive injectable duplex hybrid hydrogel (CA@HA-Gel), allowing its efficient sustained release into diabetic wounds in an inflammation-responsive manner. The results showed that CA@HA-Gel inhibited wound endothelial cell ferroptosis and significantly promoted diabetic wound healing. In summary, the results presented in this study emphasize the potential therapeutic application of CA@HA-Gel in the treatment of diseases associated with ferroptosis.

Natural Products in the Prevention of Degenerative Bone and Joint Diseases: Mechanisms Based on the Regulation of Ferroptosis

Degenerative bone and joint diseases (DBJDs), characterized by osteoporosis, osteoarthritis, and chronic inflammation of surrounding soft tissues, are systemic conditions primarily affecting the skeletal system. Ferroptosis, a programmed cell death pathway distinct from apoptosis, autophagy, and necroptosis. Accumulating evidence suggests that ferroptosis is intricately linked to the pathogenesis of DBJDs, and targeting its regulation could be beneficial in managing these conditions. Natural products, known for their anti-inflammatory and antioxidant properties, have shown unique advantages in preventing DBJDs, potentially through modulating ferroptosis. This article provides an overview of the latest research on ferroptosis, with a focus on its role in the pathogenesis of DBJDs and the therapeutic potential of natural products targeting this cell death pathway, offering novel insights for the prevention and treatment of DBJDs.

Mechanisms of Vitamins Inhibiting Ferroptosis

Ferroptosis is an iron-dependent form of cell death, which is characterized by the uncontrolled and overwhelming peroxidation of cell membrane lipids. Ferroptosis has been implicated in the progression of various pathologies, including steatotic liver, heart failure, neurodegenerative diseases, and diabetes. Targeted inhibition of ferroptosis provides a promising strategy to treat ferroptosis-related diseases. Multivitamins, including vitamins A, B, C, D, E, and K, have shown a good ability to inhibit ferroptosis. For example, vitamin A significantly upregulated the expression of several key ferroptotic gatekeepers genes through nuclear retinoic acid receptors and retinoic X receptors (RAR/RXR). Vitamin B6 could compensate for the impaired glutathione (GSH) levels and restore Glutathione peroxidase 4 (GPX4) expression in cells, ultimately inhibiting ferroptosis. Vitamin D could up-regulate the expression of several anti-ferroptosis proteins by activating vitamin D receptors. Vitamin E and hydroquinone vitamin K (VKH2) can directly inhibit the propagation of lipid peroxidation, thereby inhibiting ferroptosis. In this review, we summarize the currently understood mechanisms by which vitamins inhibit ferroptosis to provide reference information for future research on the development of ferroptosis inhibitors.

The Potential Regulatory Role of Ferroptosis in Orthodontically Induced Inflammatory Root Resorption

People, in increasing numbers, are seeking orthodontic treatment to correct malocclusion, while some of them are suffering from orthodontically induced inflammatory root resorption (OIIRR). Recent evidence suggests that the immune-inflammatory response occurring during bone remodeling may be responsible for OIIRR. Ferroptosis, a new type of programmed cell death (PCD), has been found to have a close interrelation with inflammation during disease progression. While ferroptosis has been extensively studied in bone-related diseases, its role in OIIRR is poorly understood. Considering that the tooth root shares a lot of similar characteristics with bone, it is reasonable to hypothesize that ferroptosis contributes to the development of OIIRR. Nevertheless, direct evidence supporting this theory is currently lacking. In this review, we introduced ferroptosis and elucidated the mechanisms underlying orthodontic tooth movement (OTM) and OIIRR, with a special focus on the pivotal role inflammation plays in these processes. Additionally, we covered recent research exploring the connections between inflammation and ferroptosis. Lastly, we emphasized the important regulatory function of ferroptosis in bone homeostasis. Further investigations are required to clarify the modulation mechanisms of ferroptosis in OIIRR and to develop novel and potential therapeutic strategies for the management of OIIRR.

Osteoblastic ferroptosis inhibition by small-molecule promoting GPX4 activation for peri-prosthetic osteolysis therapy

Peri-prosthesis osteolysis (PPO) represents the most severe complication of total joint arthroplasty (TJA) surgery and imposes the primary cause of prosthesis failure and subsequent revision surgery. Antiresorptive therapies are usually prescribed to treat PPO, especially for elderly people. Nevertheless, the efficacy of anti-osteoporotic medications remains constrained. Recent therapeutic strategies to promote periprosthetic osseointegration by restoring osteoblast function are considered more effective approaches. However, the precise mechanism underlying the inhibition of osteogenesis triggered by wear particles remains enigmatic. Herein, we demonstrate that wear particles inhibit osteoblast function by inducing ferroptosis to sabotage extracellular mineralization and arouse periprosthetic osteolysis. The suppression of ferroptosis could significantly rescue osteogenesis thus alleviating PPO. Furthermore, Glutathione Peroxidase 4 (GPX4) has been identified as a key target in regulating osteoblastic ferroptosis. By utilizing virtual screening techniques, we have successfully conducted a comprehensive screening of a natural compound known as Urolithin A (UA), which exhibits remarkable inhibition of osteoblastic ferroptosis while simultaneously promoting the process of osteogenesis through its precise targeting mechanism on GPX4. Meanwhile, UA improves the osteolytic conditions significantly in vivo even when the adjunction of titanium (Ti) nanoparticles. This strategy has great potential in treating peri-prosthesis osteolysis and potentially broadens the scope of clinical therapy.

Association between diabetes mellitus and trochanteric bone mineral density in individuals with osteoporotic fractures: a retrospective study

Background

The relationship between diabetes mellitus (DM) and bone mineral density (BMD) in patients with osteoporotic fractures (OPFs) remains complex and heterogeneous, specifically between the genders. This study aimed to explore the association between diabetes status and trochanteric BMD in a cohort of patients with OPFs and elucidate the differences between male and female patients.

Methods

This retrospective analysis was performed on 710 admitted patients aged 50 years or older with OPFs. In this study, the exposure variable was diabetes status. Trochanteric BMD comprised the dependent variable. While controlling for covariance influences, generalized estimating equations (GEE) were applied to examine the independent link between diabetes status and trochanteric BMD in OPFs patients. Moreover, a subgroup analysis was also conducted to validate the result's stability.

Results

A substantial positive association was noted between diabetes status and trochanteric BMD in diabetic patients, as determined by the fully adjusted model (β = 0.017, 95% CI 0.001 to 0.033, p = 0.035). Furthermore, the sex-specific analysis showed a significant positive relationship between diabetes status and trochanteric BMD in male patients (β = 0.040, 95% CI 0.006 to 0.075, p = 0.022), whereas no significant relationship was observed in female patients (β = 0.010, 95% CI -0.008 to 0.028, p = 0.256).

Conclusion

This study highlighted the significant sex differences in the impact of diabetes on trochanteric BMD among patients with OPFs. The male diabetic patients had higher trochanteric BMD than their non-diabetic counterparts; however, this association was not evident in female patients. Further research is necessary to understand the underlying mechanisms that contribute to these sex-specific differences and to evaluate the clinical implications of managing fracture risk in diabetic patients.