Engineered MgO nanoparticles for cartilage-bone synergistic therapy.

The emerging therapeutic strategies for osteoarthritis (OA) are shifting toward comprehensive approaches that target periarticular tissues, involving both cartilage and subchondral bone. This shift drives the development of single-component therapeutics capable of acting on multiple tissues and cells. Magnesium, an element essential for maintaining skeletal health, shows promise in treating OA. However, the precise effects of magnesium on cartilage and subchondral bone are not yet clear. Here, we investigated the therapeutic effect of Mg2+ on OA, unveiling its protective effects on both cartilage and bone at the cellular and animal levels. The beneficial effect on the cartilage-bone interaction is primarily mediated by the PI3K/AKT pathway. In addition, we developed poly(lactic-co-glycolic acid) (PLGA) microspheres loaded with nano-magnesium oxide modified with stearic acid (SA), MgO&SA@PLGA, for intra-articular injection. These microspheres demonstrated remarkable efficacy in alleviating OA in rat models, highlighting their translational potential in clinical applications.

Osteocyte-derived sclerostin impairs cognitive function during ageing and Alzheimer's disease progression.

Ageing increases susceptibility to neurodegenerative disorders, such as Alzheimer's disease (AD). Serum levels of sclerostin, an osteocyte-derived Wnt-ß-catenin signalling antagonist, increase with age and inhibit osteoblastogenesis. As Wnt-ß-catenin signalling acts as a protective mechanism for memory, we hypothesize that osteocyte-derived sclerostin can impact cognitive function under pathological conditions. Here we show that osteocyte-derived sclerostin can cross the blood-brain barrier of old mice, where it can dysregulate Wnt-ß-catenin signalling. Gain-of-function and loss-of-function experiments show that abnormally elevated osteocyte-derived sclerostin impairs synaptic plasticity and memory in old mice of both sexes. Mechanistically, sclerostin increases amyloid ß (Aß) production through ß-catenin-ß-secretase 1 (BACE1) signalling, indicating a functional role for sclerostin in AD. Accordingly, high sclerostin levels in patients with AD of both sexes are associated with severe cognitive impairment, which is in line with the acceleration of Αß production in an AD mouse model with bone-specific overexpression of sclerostin. Thus, we demonstrate osteocyte-derived sclerostin-mediated bone-brain crosstalk, which could serve as a target for developing therapeutic interventions against AD.

Inflammatory Fibroblast-Like Synoviocyte-Derived Exosomes Aggravate Osteoarthritis via Enhancing Macrophage Glycolysis.

The severity of osteoarthritis (OA) and cartilage degeneration is highly associated with synovial inflammation. Although recent investigations have revealed a dysregulated crosstalk between fibroblast-like synoviocytes (FLSs) and macrophages in the pathogenesis of synovitis, limited knowledge is available regarding the involvement of exosomes. Here, increased exosome secretion is observed in FLSs from OA patients. Notably, internalization of inflammatory FLS-derived exosomes (inf-exo) can enhance the M1 polarization of macrophages, which further induces an OA-like phenotype in co-cultured chondrocytes. Intra-articular injection of inf-exo induces synovitis and exacerbates OA progression in murine models. In addition, it is demonstrated that inf-exo stimulation triggers the activation of glycolysis. Inhibition of glycolysis using 2-DG successfully attenuates excessive M1 polarization triggered by inf-exo. Mechanistically, HIF1A is identified as the determinant transcription factor, inhibition of which, both pharmacologically or genetically, relieves macrophage inflammation triggered by inf-exo-induced hyperglycolysis. Furthermore, in vivo administration of an HIF1A inhibitor alleviates experimental OA. The results provide novel insights into the involvement of FLS-derived exosomes in OA pathogenesis, suggesting that inf-exo-induced macrophage dysfunction represents an attractive target for OA therapy.

Elimination of Senescent Osteocytes by Bone-Targeting Delivery of ß-Galactose-Modified Maytansinoid Prevents Age-Related Bone Loss.

The accumulation of senescent cells in bone during aging contributes to senile osteoporosis, and clearance of senescent cells by senolytics could effectively alleviate bone loss. However, the applications of senolytics are limited due to their potential toxicities. Herein, small extracellular vesicles (sEVs) have been modified by incorporating bone-targeting peptide, specifically (AspSerSer)6 , to encapsulate galactose-modified Maytansinoids (DM1). These modified vesicles are referred to as (AspSerSer)6 -sEVs/DM1-Gal, and they have been designed to specifically clear the senescent osteocytes in bone tissue. In addition, the elevated activity of lysosomal ß-galactosidase in senescent osteocytes, but not normal cells in bone tissue, could break down DM1-Gal to release free DM1 for selective elimination of senescent osteocytes. Mechanically, DM1 could disrupt tubulin polymerization, subsequently inducing senescent osteocytes apoptosis. Further, administration of bone-targeting senolytics to aged mice could alleviate aged-related bone loss without non-obvious toxicity. Overall, this bone-targeting senolytics could act as a novel candidate for specific clearance of senescent osteocytes, ameliorating age-related bone loss, with a promising therapeutic potential for senile osteoporosis.

Overexpression of fibroblast growth factor receptor 2 in bone marrow mesenchymal stem cells enhances osteogenesis and promotes critical cranial bone defect regeneration.

Background: Reconstruction of cranial bone defects is one of the most challenging problems in reconstructive surgery, and several biological tissue engineering methods have been used to promote bone repair, such as genetic engineering of bone marrow mesenchymal stem cells (BMSCs). Fibroblast growth factor receptor 2 (Fgfr2) is an important regulator of bone construction and can be used as a potential gene editing site. However, its role in the osteogenesis process of BMSCs remains unclear. This article clarifies the function of Fgfr2 in BMSCs and explores the role of Fgfr2-overexpressed BMSCs carried by light-induced porous hydrogel (GelMA) in the repair of cranial bone defects. Methods: Lenti-virus was used to overexpress Fgfr2 in BMSCs, and cell counting kit-8, transwell, and flow cytometry assays were conducted to investigate the proliferation, migration, and characteristics. After 0, 3, 7, and 10 days of osteogenic or chondrogenic induction, the changes in osteogenic and chondrogenic ability were detected by real-time PCR, western blot, alkaline phosphatase staining, alizarin Red staining, and alcian blue staining. To investigate the viability of BMSCs carried by GelMA, calcein and propyl iodide staining were carried out as well. Finally, a critical cranial bone defect model was established in 6-week-old male mice and micro-computerized tomography, masson staining, and immunohistochemistry of OCN were conducted to test the bone regeneration properties of implanting Fgfr2-overexpressed BMSCs with GelMA in cranial bone defects over 6 weeks. Results: Overexpression of Fgfr2 in BMSCs significantly promoted cell proliferation and migration and increased the percentage of CD200+CD105+ cells. After osteogenic and chondrogenic induction, Fgfr2 overexpression enhanced both osteogenic and chondrogenic ability. Furthermore, in cranial bone defect regeneration, BMSCs carried by light-induced GelMA showed favorable biocompatibility, and Fgfr2-overexpressed BMSCs induced superior cranial bone regeneration compared to a normal BMSCs group and an untreated blank group. Conclusion: In vitro, Fgfr2 enhanced the proliferation, migration, and stemness of BMSCs and promoted osteogenesis and chondrogenesis after parallel induction. In vivo, BMSCs with Fgfr2 overexpression carried by GelMA showed favorable performance in treating critical cranial bone defects. This study clarifies the multiple functions of Fgfr2 in BMSCs and provides a new method for future tissue engineering.

ZBTB7C m6A modification incurred by METTL3 aberration promotes osteosarcoma progression.

Aberrant N6-methyladenosine (m6A) modification of mRNAs contributes significantly to the epigenetic tumorigenesis, however, its precise role and the key targets in osteosarcoma (OS) are not defined. Here we reported that selective METTL3 (methyltransferase like 3) elevation and the consequential increase of m6A modification causally affect OS progression. The fast-growing OS cells displayed preferential upregulation of METTL3 and increased m6A modification. Conversely, m6A inhibition by 3-deazaadenosine, siRNA-mediated METTL3 knockdown or a METTL3-selective inhibitor STM2457 effectively inhibits OS cell growth and induced OS cell apoptosis. Further investigation revealed that an oncogenic protein ZBTB7C was likely a critical m6A target that mediated the oncogenic effects. ZBTB7C mRNA contains a typical m6A motif of high confidence and its mRNA and protein were enriched with increased m6A modification in OS samples/cells. In an OS xenograft model, STM2457 or siRNA-mediated METTL3 knockdown effectively lowed ZBTB7C abundance. More importantly, the anti-OS effects of STM2457 were significantly reduced when ZBTB7C was overexpressed by lentivirus. Together, our results demonstrate that the METTL3 aberration and the resultant ZBTB7C m6A modification form an important epigenetic regulatory loop that promotes OS progression, and targeting the METTL3/ZBTB7C axis may provide novel insights into the potential strategies for OS therapy.

Atrophic skeletal muscle fibre-derived small extracellular vesicle miR-690 inhibits satellite cell differentiation during ageing.

BACKGROUND: Sarcopenia is a common and progressive skeletal muscle disorder characterized by atrophic muscle fibres and contractile dysfunction. Accumulating evidence shows that the number and function of satellite cells (SCs) decline and become impaired during ageing, which may contribute to impaired regenerative capacity. A series of myokines/small extracellular vesicles (sEVs) released from muscle fibres regulate metabolism in muscle and extramuscular tissues in an autocrine/paracrine/endocrine manner during muscle atrophy. It is still unclear whether myokines/sEVs derived from muscle fibres can affect satellite cell function during ageing. METHODS: Aged mice were used to investigate changes in the myogenic capacity of SCs during ageing-induced muscle atrophy. The effects of atrophic myotube-derived sEVs on satellite cell differentiation were investigated by biochemical methods and immunofluorescence staining. Small RNA sequencing was performed to identify differentially expressed sEV microRNAs (miRNAs) between the control myotubes and atrophic myotubes. The target genes of the miRNA were predicted by bioinformatics analysis and verified by luciferase activity assays. The effects of identified miRNA on the myogenic capacity of SCs in vivo were investigated by intramuscular injection of adeno-associated virus (AAV) to overexpress or silence miRNA in skeletal muscle. RESULTS: Our study showed that the myogenic capacity of SCs was significantly decreased (50%, n = 6, P < 0.001) in the tibialis anterior muscle of aged mice. We showed that atrophic myotube-derived sEVs inhibited satellite cell differentiation in vitro (n = 3, P < 0.001) and in vivo (35%, n = 6, P < 0.05). We also found that miR-690 was the most highly enriched miRNA among all the screened sEV miRNAs in atrophic myotubes [Log2 (Fold Change) = 7, P < 0.001], which was verified in the atrophic muscle of aged mice (threefold, n = 6, P < 0.001) and aged men with mean age of 71 ± 5.27 years (2.8-fold, n = 10, P < 0.001). MiR-690 can inhibit myogenic capacity of SCs by targeting myocyte enhancer factor 2, including Mef2a, Mef2c and Mef2d, in vitro (n = 3, P < 0.05) and in vivo (n = 6, P < 0.05). Specific silencing of miR-690 in the muscle can promote satellite cell differentiation (n = 6, P < 0.001) and alleviate muscle atrophy in aged mice (n = 6, P < 0.001). CONCLUSIONS: Our study demonstrated that atrophic muscle fibre-derived sEV miR-690 may inhibit satellite cell differentiation by targeting myocyte enhancer factor 2 during ageing.

Heterozygous LRP1 deficiency causes developmental dysplasia of the hip by impairing triradiate chondrocytes differentiation due to inhibition of autophagy.

Developmental dysplasia of the hip (DDH) is one of the most common congenital skeletal malformations; however, its etiology remains unclear. Here, we conducted whole-exome sequencing in eight DDH families followed by targeted sequencing of 68 sporadic DDH patients. We identified likely pathogenic variants in the LRP1 (low-density lipoprotein receptor-related protein 1) gene in two families and seven unrelated patients. All patients harboring the LRP1 variants presented a typical DDH phenotype. The heterozygous Lrp1 knockout (KO) mouse (Lrp1+/-) showed phenotypes recapitulating the human DDH phenotypes, indicating Lrp1 loss of function causes DDH. Lrp1 knockin mice with a missense variant corresponding to a human variant identified in DDH (Lrp1R1783W) also presented DDH phenotypes, which were milder in heterozygotes and severer in homozygotes than those of the Lrp1 KO mouse. The timing of triradiate cartilage development was brought forward 1 or 2 wk earlier in the LRP-deficient mice, which leads to malformation of the acetabulum and femoral head. Furthermore, Lrp1 deficiency caused a significant decrease of chondrogenic ability in vitro. During the chondrogenic induction of mice bone marrow stem cells and ATDC5 (an inducible chondrogenic cell line), Lrp1 deficiency caused decreased autophagy levels with significant ß-catenin up-regulation and suppression of chondrocyte marker genes. The expression of chondrocyte markers was rescued by PNU-74654 (a ß-catenin antagonist) in an shRNA-Lrp1-expressed ATDC5 cell. Our study reveals a critical role of LRP1 in the etiology and pathogenesis of DDH, opening an avenue for its treatment.

Reprogramming Mitochondrial Metabolism in Synovial Macrophages of Early Osteoarthritis by a Camouflaged Meta-Defensome.

Osteoarthritis (OA) is a low-grade inflammatory and progressive joint disease, and its progression is closely associated with an imbalance in M1/M2 synovial macrophages. Repolarizing pro-inflammatory M1 macrophages into the anti-inflammatory M2 phenotype is emerging as a strategy to alleviate OA progression but is compromised by unsatisfactory efficiency. In this study, the reprogramming of mitochondrial dysfunction is pioneered with a camouflaged meta-Defensome, which can transform M1 synovial macrophages into the M2 phenotype with a high efficiency of 82.3%. The meta-Defensome recognizes activated macrophages via receptor-ligand interactions and accumulates in the mitochondria through electrostatic attractions. These meta-Defensomes are macrophage-membrane-coated polymeric nanoparticles decorated with dual ligands and co-loaded with S-methylisothiourea and MnO2 . Meta-Defensomes are demonstrated to successfully reprogram the mitochondrial metabolism of M1 macrophages by scavenging mitochondrial reactive oxygen species and inhibiting mitochondrial NO synthase, thereby increasing mitochondrial transcription factor A expression and restoring aerobic respiration. Furthermore, meta-Defensomes are intravenously injected into collagenase-induced osteoarthritis mice and effectively suppress synovial inflammation and progression of early OA, as evident from the Osteoarthritis Research Society International score. Therefore, reprogramming the mitochondrial metabolism can serve as a novel and practical approach to repolarize M1 synovial macrophages. The camouflaged meta-Defensomes are a promising therapeutic agent for impeding OA progression in tclinic.

METTL3-mediated m6A modification of ATG7 regulates autophagy-GATA4 axis to promote cellular senescence and osteoarthritis progression.

OBJECTIVE: The aim of the study was to investigate the role and regulatory mechanisms of fibroblast-like synoviocytes (FLSs) and their senescence in the progression of osteoarthritis (OA). METHODS: Synovial tissues from normal patients and patients with OA were collected. Synovium FLS senescence was analysed by immunofluorescence and western blotting. The role of methyltransferase-like 3 (METTL3) in autophagy regulation was explored using N6-methyladenosine (m6A)-methylated RNA and RNA immunoprecipitation assays. Mice subjected to destabilisation of the medial meniscus (DMM) surgery were intra-articularly injected with or without pAAV9 loaded with small interfering RNA (siRNA) targeting METTL3. Histological analysis was performed to determine cartilage damage. RESULTS: Senescent FLSs were markedly increased with the progression of OA in patients and mouse models. We determined that impaired autophagy occurred in OA-FLS, resulting in the upregulation of senescence-associated secretory phenotype (SASP). Re-establishment of autophagy reversed the senescent phenotype by suppressing GATA4. Further, we observed for the first time that excessive m6A modification negatively regulated autophagy in OA-FLS. Mechanistically, METTL3-mediated m6A modification decreased the expression of autophagy-related 7, an E-1 enzyme crucial for the formation of autophagosomes, by attenuating its RNA stability. Silencing METTL3 enhanced autophagic flux and inhibited SASP expression in OA-FLS. Intra-articular injection of synovium-targeted METTL3 siRNA suppressed cellular senescence propagation in joints and ameliorated DMM-induced cartilage destruction. CONCLUSIONS: Our study revealed the important role of FLS senescence in OA progression. Targeted METTL3 inhibition could alleviate the senescence of FLS and limit OA development in experimental animal models, providing a potential strategy for OA therapy.

Genomic and GWAS analyses demonstrate phylogenomic relationships of Gossypium barbadense in China and selection for fibre length, lint percentage and Fusarium wilt resistance.

Sea Island cotton (Gossypium barbadense) is the source of the world's finest fibre quality cotton, yet relatively little is understood about genetic variations among diverse germplasms, genes underlying important traits and the effects of pedigree selection. Here, we resequenced 336 G. barbadense accessions and identified 16 million SNPs. Phylogenetic and population structure analyses revealed two major gene pools and a third admixed subgroup derived from geographical dissemination and interbreeding. We conducted a genome-wide association study (GWAS) of 15 traits including fibre quality, yield, disease resistance, maturity and plant architecture. The highest number of associated loci was for fibre quality, followed by disease resistance and yield. Using gene expression analyses and VIGS transgenic experiments, we confirmed the roles of five candidate genes regulating four key traits, that is disease resistance, fibre length, fibre strength and lint percentage. Geographical and temporal considerations demonstrated selection for the superior fibre quality (fibre length and fibre strength), and high lint percentage in improving G. barbadense in China. Pedigree selection breeding increased Fusarium wilt disease resistance and separately improved fibre quality and yield. Our work provides a foundation for understanding genomic variation and selective breeding of Sea Island cotton.

Network Pharmacology-Based Strategy for the Investigation of the Anti-Osteoporosis Effects and Underlying Mechanism of Zhuangguguanjie Formulation.

As the society is aging, the increasing prevalence of osteoporosis has generated huge social and economic impact, while the drug therapy for osteoporosis is limited due to multiple targets involved in this disease. Zhuangguguanjie formulation (ZG) is extensively used in the clinical treatment of bone and joint diseases, but the underlying mechanism has not been fully described. This study aimed to examine the therapeutic effect and potential mechanism of ZG on postmenopausal osteoporosis. The ovariectomized (OVX) mice were treated with normal saline or ZG for 4 weeks after ovariectomy following a series of analyses. The bone mass density (BMD) and trabecular parameters were examined by micro-CT. Bone remodeling was evaluated by the bone histomorphometry analysis and ELISA assay of bone turnover biomarkers in serum. The possible drug-disease common targets were analyzed by network pharmacology. To predict the potential biological processes and related pathways, GO/KEGG enrichment analysis was performed. The effects of ZG on the differentiation phenotype of osteoclasts and osteoblasts and the predicted pathway were verified in vitro. The results showed that ZG significantly improved the bone mass and micro-trabecular architecture in OVX mice compared with untreated OVX mice. ZG could promote bone formation and inhibit bone resorption to ameliorate ovariectomy-induced osteoporosis as evidenced by increased number of osteoblast (N.Ob/Tb.Pm) and decreased number of osteoclast (N.Oc/Tb.Pm) in treated group compared with untreated OVX mice. After identifying potential drug-disease common targets by network pharmacology, GO enrichment analysis predicted that ZG might affect various biological processes including osteoblastic differentiation and osteoclast differentiation. The KEGG enrichment analysis suggested that PI3K/Akt and mTOR signaling pathways could be the possible pathways. Furthermore, the experiments in vitro validated our findings. ZG significantly down-regulated the expression of osteoclast differentiation markers, reduced osteoclastic resorption, and inhibited the phosphorylation of PI3K/Akt, while ZG obviously up-regulated the expression of osteogenic biomarkers, promoted the formation of calcium nodules, and hampered the phosphorylation of 70S6K1/mTOR, which can be reversed by the corresponding pathway activator. Thus, our study suggested that ZG could inhibit the PI3K/Akt signaling pathway to reduce osteoclastic bone resorption as well as hamper the mTORC1/S6K1 signaling pathway to promote osteoblastic bone formation.

Evaluating the bio-application of biomacromolecule of lignin-carbohydrate complexes (LCC) from wheat straw in bone metabolism via ROS scavenging.

Lignin-carbohydrate complexes (LCC) arebiomacromolecules that can be obtained from different biomass. Even some works have shown the LCC can efficiently scavenge the intracellular and endogenous reactive oxygen species (ROS), while little work has been carried out to investigate the potential application of LCC for ROS-related treatment in biological filed, especially for the treatment of periprosthetic osteolysis in vivo. In this work, Lignin-rich (LCC-A) and carbohydrate-rich (LCC-B) fractions in wheat straw are isolated and used as the ROS scavenger to promote osteoblast differentiation and inhibit osteoclast differentiation. The chemical composition and structures are characterized by high performance anion exchange chromatography (HPAEC) and nuclear magnetic resonance (NMR) technologies (quantitative 13C NMR and 2D-HSQC NMR), respectively. The results showed LCC-A possesses higher in vitro ROS-scavenging ability than LCC-B (89.8% vs 57.8%) and to inhibit osteoclast differentiation, whereas LCC-B more significantly activates cellular antioxidant activities via the KEAP1-NRF2-ARE pathway (218.5% vs 438.0% in the level of HO-1), thus promoting osteoblast differentiation in an inflammatory environment. Moreover, the therapeutic administration of LCC-A and LCC-B for Ti-particle-induced osteolytic murine calvariae showed both of them positively regulate and restore the bone metabolism, while preventing calvaria impairment. Hence, LCC from wheat straw exhibits efficient bone protective effects, suggesting it may be used as the promising ROS scavenger for clinical treatment of periprosthetic osteolysis.

A Calmodulin-Like Gene (GbCML7) for Fiber Strength and Yield Improvement Identified by Resequencing Core Accessions of a Pedigree in Gossypium barbadense.

Sea Island cotton (Gossypium barbadense) is world-renowned for its superior natural fiber. Although fiber strength is one of the most important fiber quality traits, genes contributing to fiber strength are poorly understood. Production of sea island cotton also is inextricably linked to improving its relatively low yield, thus enhancing the importance of joint improvement of both fiber quality and yield. We used genomic variation to uncover the genetic evidence of trait improvement resulting from pedigree breeding of Sea Island cotton. This pedigree was aimed at improving fiber strength and yielded an elite cultivar, XH35. Using a combination of genome-wide association study (GWAS) and selection screens, we detected 82 putative fiber-strength-related genes. Expression analysis confirmed a calmodulin-like gene, GbCML7, which enhanced fiber strength in a specific haplotype. This gene is a major-effect gene, which interacts with a minor-effect gene, GbTUA3, facilitating the enhancement of fiber strength in a synergistic fashion. Moreover, GbCML7 participates in the cooperative improvement of fiber strength, fiber length, and fiber uniformity, though a slight compromise exists between the first two of these traits and the latter. Importantly, GbCML7 is shown to boost yield in some backgrounds by increasing multiple yield components to varying degrees, especially boll number. Our work provides valuable genomic evidence and a key genetic factor for the joint improvement of fiber quality and yield in Sea Island cotton.

Development of a novel polysaccharide-based iron oxide nanoparticle to prevent iron accumulation-related osteoporosis by scavenging reactive oxygen species.

In this work, the biological polysaccharide-based antioxidant polyglucose-sorbitol-carboxymethyl ether (PSC) was used as the precursor to synthesize Fe2O3@PSC nanoparticles, which are expected to scavenge excess reactive oxygen species (ROS) to inhibit osteogenesis and promote osteoclast differentiation in iron accumulation (IA)-related osteoporosis. The Fe2O3@PSC nanoparticles obtained were of a uniform particle size of 7.3 nm with elemental O/Fe/Cl/C at a ratio of 190:7:2:88. In addition, the Fe2O3@PSC nanoparticles showed the ability to supply equivalent amounts of iron as the typical iron agent ferric ammonium citrate (FAC) in vitro and in vivo. Importantly, the Fe2O3@PSC nanoparticles not only induced antioxidative MC3T3-E1 and Raw 264.7 cells to scavenge ROS but also promoted osteogenic differentiation by activating Akt-GSK-3ß-ß-catenin and inhibiting osteoclast differentiation by inhibiting the MAPK and NF-κB pathways in vitro. In vivo, no IA-related osteoporosis was induced in a mouse model when enough iron was supplied by the Fe2O3@PSC nanoparticles. Overall, the biological polysaccharide-based antioxidant PSC can supply iron and prevent IA-related osteoporosis, indicating that it is a promising novel iron agent for applications to treat iron deficiency diseases.

Author Correction: HIF1α inhibition facilitates Leflunomide-AHR-CRP signaling to attenuate bone erosion in CRP-aberrant rheumatoid arthritis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

HIF1α inhibition facilitates Leflunomide-AHR-CRP signaling to attenuate bone erosion in CRP-aberrant rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by progressive bone erosion. Leflunomide is originally developed to suppress inflammation via its metabolite A77 1726 to attenuate bone erosion. However, distinctive responsiveness to Leflunomide is observed among RA individuals. Here we show that Leflunomide exerts immunosuppression but limited efficacy in RA individuals distinguished by higher serum C-reactive protein (CRPHigher, CRPH), whereas the others with satisfactory responsiveness to Leflunomide show lower CRP (CRPLower, CRPL). CRP inhibition decreases bone erosion in arthritic rats. Besides the immunomodulation via A77 1726, Leflunomide itself induces AHR-ARNT interaction to inhibit hepatic CRP production and attenuate bone erosion in CRPL arthritic rats. Nevertheless, high CRP in CRPH rats upregulates HIF1α, which competes with AHR for ARNT association and interferes Leflunomide-AHR-CRP signaling. Hepatocyte-specific HIF1α deletion or a HIF1α inhibitor Acriflavine re-activates Leflunomide-AHR-CRP signaling to inhibit bone erosion. This study presents a precision medicine-based therapeutic strategy for RA.

Osteoblastic PLEKHO1 contributes to joint inflammation in rheumatoid arthritis.

BACKGROUND: Osteoblasts participating in the inflammation regulation gradually obtain concerns. However, its role in joint inflammation of rheumatoid arthritis (RA) is largely unknown. Here, we investigated the role of osteoblastic pleckstrin homology domain-containing family O member 1 (PLEKHO1), a negative regulator of osteogenic lineage activity, in regulating joint inflammation in RA. METHODS: The level of osteoblastic PLEKHO1 in RA patients and collagen-induced arthritis (CIA) mice was examined. The role of osteoblastic PLEKHO1 in joint inflammation was evaluated by a CIA model and a K/BxN serum-transfer arthritis (STA) model which were induced in osteoblast-specific Plekho1 conditional knockout mice and mice expressing high Plekho1 exclusively in osteoblasts, respectively. The effect of osteoblastic PLEKHO1 inhibition was explored in a CIA mice model and a non-human primate arthritis model. The mechanism of osteoblastic PLEKHO1 in regulating joint inflammation were performed by a series of in vitro studies. RESULTS: PLEKHO1 was highly expressed in osteoblasts from RA patients and CIA mice. Osteoblastic Plekho1 deletion ameliorated joint inflammation, whereas overexpressing Plekho1 only within osteoblasts exacerbated local inflammation in CIA mice and STA mice. PLEKHO1 was required for TRAF2-mediated RIP1 ubiquitination to activate NF-κB for inducing inflammatory cytokines production in osteoblasts. Moreover, osteoblastic PLEKHO1 inhibition diminished joint inflammation and promoted bone formation in CIA mice and non-human primate arthritis model. CONCLUSIONS: These data strongly suggest that the highly expressed PLEKHO1 in osteoblasts contributes to joint inflammation in RA. Targeting osteoblastic PLEKHO1 may exert dual therapeutic action of alleviating joint inflammation and promoting bone formation in RA.

Bushen Yijing Fang Reduces Fall Risk in Late Postmenopausal Women with Osteopenia: A Randomized Double-blind and Placebo-controlled Trial.

Falls in late postmenopausal women with osteopenia usually cause fractures with severe consequences. This 36-month randomized, double-blind and placebo-controlled trial with a 10-year observational follow-up study aimed to investigate the long-term effect of herbal formula Bushen Yijing Fang (BSYJF) on fall risk in the late postmenopausal women with osteopenia. 140 late postmenopausal women (Femoral neck T-score, -2.5~-2 SD) were recruited and randomized to orally receive calcium carbonate 300 mg daily with either BSYJF or placebo for 36 months. The effect was further investigated for another 10-year follow-up. During the 36-month administration, there were 12 falls in BSYJF group and 28 falls in placebo group, respectively, indicating 64% lower risk of falls (RR 0.36 [95% CI, 0.18 to 0.71]; P = 0.004) in BSYJF group. During the 10-year follow-up, 36% lower fall risk (RR 0.64 [95% CI, 0.46 to 0.89]; P = 0.009) was observed in BSYJF group. No significant difference was found in safety profile between two groups. Thirty-six-month administration of BSYJF reduced fall risk with an increase in bone mass, and its latent effect on fall risk was continually observed in the 10-year follow-up in late postmenopausal women with osteopenia. This clinical trial was registered at Chinese clinical trial registry (ChiCTR-IOR-16008942).