FAR591 promotes the pathogenesis and progression of SONFH by regulating Fos expression to mediate the apoptosis of bone microvascular endothelial cells

The specific pathogenesis of steroid-induced osteonecrosis of the femoral head(SONFH)is still not fully understood,and there is currently no effective early cure.Understanding the role and mechanism of long noncoding RNAs(lnc RNAs)in the pathogenesis of SONFH will help reveal the pathogenesis of SONFH and provide new targets for its early prevention and treatment.In this study,we first confirmed that glucocorticoid(GC)-induced apoptosis of bone microvascular endothelial cells(BMECs)is a pre-event in the pathogenesis and progression of SONFH.Then,we identified a new lnc RNA in BMECs via lnc RNA/m RNA microarray,termed Fosassociated linc RNA ENSRNOT00000088059.1(FAR591).FAR591 is highly expressed during GC-induced BMEC apoptosis and femoral head necrosis.Knockout of FAR591 effectively blocked the GC-induced apoptosis of BMECs,which then alleviated the damage of GCs to the femoral head microcirculation and inhibited the pathogenesis and progression of SONFH.In contrast,overexpression of FAR591 significantly promoted the GC-induced apoptosis of BMECs,which then aggravated the damage of GCs to the femoral head microcirculation and promoted the pathogenesis and progression of SONFH.Mechanistically,GCs activate the glucocorticoid receptor,which translocates to the nucleus and directly acts on the FAR591 gene promoter to induce FAR591 gene overexpression.Subsequently,FAR591 binds to the Fos gene promoter(–245–51)to form a stable RNA:DNA triplet structure and then recruits TATA-box binding protein associated factor 15 and RNA polymerase II to promote Fos expression through transcriptional activation.Fos activates the mitochondrial apoptotic pathway by regulating the expression of Bcl-2 interacting mediator of cell death(Bim)and P53 upregulated modulator of apoptosis(Puma)to mediate GC-induced apoptosis of BMECs,which leads to femoral head microcirculation dysfunction and femoral head necrosis.In conclusion,these results confirm the mechanistic link between lnc RNAs and the pathogenesis of SONFH,which helps reveal the pathogenesis of SONFH and provides a new target for the early prevention and treatment of SONFH.

3D-bioprinted anisotropic bicellular living hydrogels boost osteochondral regeneration via reconstruction of cartilage–bone interface

Reconstruction of osteochondral(OC)defects represents an immense challenge due to the need for synchronous regeneration of special stratified tissues.The revolutionary innovation of bioprinting provides a robust method for precise fabrication of tissue-engineered OCs with hierarchical structure;however,their spatial living cues for simultaneous fulfilment of osteogenesis and chondrogenesis to reconstruct the cartilage-bone interface of OC are underappreciated.Here,inspired by natural OC bilayer features,anisotropic bicellular living hydrogels(ABLHs)simultaneously embedding articular cartilage progenitor cells(ACPCs)and bone mesenchymal stem cells(BMSCs)in stratified layers were precisely fabricated via two-channel extrusion bioprinting.The optimum formulation of the 7%GelMA/3%AlgMA hydrogel bioink was demonstrated,with excellent printability at room temperature and maintained high cell viability.Moreover,the chondrogenic ability of ACPCs and the osteogenic ability of BMSCs were demonstrated in vitro,confirming the inherent differential spatial regulation of ABLHs.

Irisin-loaded electrospun core-shell nanofibers as calvarial periosteum accelerate vascularized bone regeneration by activating the mitochondrial SIRT3 pathway

The scarcity of native periosteum poses a significant clinical barrier in the repair of critical-sized bone defects.The challenge of enhancing regenerative potential in bone healing is further compounded by oxidative stress at the fracture site.However,the introduction of artificial periosteum has demonstrated its ability to promote bone regeneration through the provision of appropriate mechanical support and controlled release of proosteogenic factors.In this study,a poly(L-lactic acid)(PLLA)/hyaluronic acid(HA)-based nanofibrous membrane was fabricated using the coaxial electrospinning technique.The incorporation of irisin into the core-shell structure of PLLA/HA nanofibers(PLLA/HA@Irisin)achieved its sustained release.In vitro experiments demonstrated that the PLLA/HA@Irisin membranes exhibited favorable biocompatibility.The osteogenic differentiation of bone marrow mesenchymal stem cells(BMMSCs)was improved by PLLA/HA@Irisin,as evidenced by a significant increase in alkaline phosphatase activity and matrix mineralization.Mechanistically,PLLA/HA@Irisin significantly enhanced the mitochondrial function of BMMSCs via the activation of the sirtuin 3 antioxidant pathway.To assess the therapeutic effectiveness,PLLA/HA@Irisin membranes were implanted in situ into critical-sized calvarial defects in rats.The results at 4 and 8 weeks post-surgery indicated that the implantation of PLLA/HA@Irisin exhibited superior efficacy in promoting vascularized bone formation,as demonstrated by the enhancement of bone matrix synthesis and the development of new blood vessels.The results of our study indicate that the electrospun PLLA/HA@Irisin nanofibers possess characteristics of a biomimetic periosteum,showing potential for effectively treating critical-sized bone defects by improving the mitochondrial function and maintaining redox homeostasis of BMMSCs.

Cartilage-inspired self-assembly glycopeptide hydrogels for cartilage regeneration via ROS scavenging

Cartilage injury represents a frequent dilemma in clinical practice owing to its inherently limited self-renewal capacity.Biomimetic strategy-based engineered biomaterial,capable of coordinated regulation for cellular and microenvironmental crosstalk,provides an adequate avenue to boost cartilage regeneration.The level of oxidative stress in microenvironments is verified to be vital for tissue regeneration,yet it is often overlooked in engineered biomaterials for cartilage regeneration.Herein,inspired by natural cartilage architecture,a fibril-network glycopeptide hydrogel(Nap-FFGRGD@FU),composed of marine-derived polysaccharide fucoidan(FU)and naphthalenephenylalanine-phenylalanine-glycine-arginine-glycine-aspartic peptide(Nap-FFGRGD),was presented through a simple supramolecular self-assembly approach.The Nap-FFGRGD@FU hydrogels exhibit a native cartilage-like architecture,characterized by interwoven collagen fibers and attached proteoglycans.Beyond structural simulation,fucoidan-exerted robust biological effects and Arg-Gly-Asp(RGD)sequence-provided cell attachment sites realized functional reinforcement,synergistically promoted extracellular matrix(ECM)production and reactive oxygen species(ROS)elimination,thus contributing to chondrocytes-ECM harmony.In vitro co-culture with glycopeptide hydrogels not only facilitated cartilage ECM anabolic metabolism but also scavenged ROS accumulation in chondrocytes.Mechanistically,the chondro-protective effects induced by glycopeptide hydrogels rely on the activation of endogenous antioxidant pathways associated with nuclear factor erythroid 2-related factor 2(NRF2).In vivo implantation of glycopeptide hydrogels successfully improved the de novo cartilage generation by 1.65-fold,concomitant with coordinately restructured subchondral bone structure.Collectively,our ingeniously crafted bionic glycopeptide hydrogels simultaneously rewired chondrocytes’function by augmenting anabolic metabolism and rebuilt ECM microenvironment via preserving redox equilibrium,holding great potential for cartilage tissue engineering.

Substrate stiffness modulates bone marrow-derived macrophage polarization through NF-κB signaling pathway

The stiffness of the extracellular matrix(ECM)plays an important role in regulating the cellular programming.However,the mechanical characteristics of ECM affecting cell differentiation are still under investigated.Herein,we aimed to study the effect of ECM substrate stiffness on macrophage polarization.We prepared polyacrylamide hydrogels with different substrate stiffness,respectively.After the hydrogels were confirmed to have a good biocompatibility,the bone marrow-derived macrophages(BMMs)from mice were incubated on the hydrogels.With simulated by the low substrate stiffness,BMMs displayed an enhanced expression of CD86 on the cell surface and production of reactive oxygen species(ROS)in cells,and secreted more IL-1βand TNF-αin the supernatant.On the contrary,stressed by the medium stiffness,BMMs expressed more CD206,produced less ROS,and secreted more IL-4 and TGF-β.In vivo study by delivered the hydrogels subcutaneously in mice,more CD68+CD86+cells around the hydrogels with the low substrate stiffness were observed while more CD68+CD206+cells near by the middle stiffness hydrogels.In addition,the expressions of NIK,phosphorylated p65(pi-p65)and phosphorylated IκB(pi-IκB)were significantly increased after stimulation with low stiffness in BMMs.Taken together,these findings demonstrated that substrate stiffness could affect macrophages polarization.Low substrate stiffness promoted BMMs to shift to classically activated macrophages(M1)and the middle one to alternatively activated macrophages(M2),through modulating ROS-initiated NF-κB pathway.Therefore,we anticipated ECM-based substrate stiffness with immune modulation would be under consideration in the clinical applications if necessary.

High-resolution sea surface wind speeds of Super Typhoon Lekima (2019) retrieved by Gaofen-3 SAR

Gaofen-3(GF-3)is the first Chinese spaceborne multi-polarization synthetic aperture radar(SAR)instrument at C-band(5.43 GHz).In this paper,we use data collected from GF-3 to observe Super Typhoon Lekima(2019)in the East China Sea.Using a VH-polarized wide ScanSAR(WSC)image,ocean surface wind speeds at 100m horizontal resolution are obtained at 21:56:59 UTC on 8 August 2019,with the maximum wind speed,38.9 m·s^(-1).Validating the SAR-retrieved winds with buoymeasured wind speeds,we find that the root mean square error(RMSE)is 1.86 m·s^(-1),and correlation coefficient,0.92.This suggests that wind speeds retrieved from GF-3 SAR are reliable.Both the European Centre for MediumRange Weather Forecasts(ECMWF)fine grid operational forecast products with spatial resolution,and China Global/Regional Assimilation and Prediction Enhance System(GRAPES)have good performances on surface wind prediction under weak wind speed condition(<24 m·s^(-1)),but underestimate the maximum wind speed when the storm is intensified as a severe tropical storm(>24m·s^(-1)).With respect to SAR-retrieved wind speeds,the RMSEs are 5.24 m·s^(–1) for ECMWF and 5.17 m·s^(–1) for GRAPES,with biases of 4.16 m·s^(–1) for ECMWF and 3.84 m·s^(-1)for GRAPES during Super Typhoon Lekima(2019).

Biomimetic melatonin-loaded silk fibroin/GelMA scaffold strengthens cartilage repair through retrieval of mitochondrial functions

Articular cartilage injury induced by collision or trauma is a common sports-related condition that may progress to pain,dysfunction,and secondary osteoarthritis(OA).Limited by self-renewal potential,cartilage regeneration faces a quandary while bio-inspired novel strategies are urgently required.In this study,by a soft freezing method and surface modification technique,a multi-functional silk fibroin(SF)plus gelatin methacrylate(GelMA)scaffold laden with melatonin(MT)was prepared.SF-GelMA@MT scaffold demonstrated enhanced biomechanical characteristics and long-acting melatonin release.In vitro treatment with SF-GelMA@MT induced the synthesis of cartilage extracellular matrix(ECM)components.Mechanistically,sustained release of melatonin yielded robust chondroprotective effects via improving mitochondrial polarization and antioxidant properties.SF-GelMA@MT implantation boosted cartilage renascence in a full-thickness cartilage defect model via mitochondria-associated sirtuins 1(SIRT1)-superoxide dismutase 2(SOD2)signaling pathway in vivo.In summary,this research proposed a welldesigned bionic composite scaffold that promotes cartilage regeneration via mitochondrial function enhancement,which is of tremendous potential for cartilage tissue engineering.

Incorporation of kartogenin and silk fibroin scaffolds promotes rat articular cartilage regeneration through enhancement of antioxidant functions

Treating articular cartilage defects in patients remains a challenging task due to the absence of blood vessels within the cartilage tissue.The regenerative potential is further compromised by an imbalance between anabolism and catabolism,induced by elevated levels of reactive oxygen species.However,the advent of tissue engineering introduces a promising strategy for cartilage regeneration,offering viable solutions such as mechanical support and controlled release of chondrogenic molecules or cytokines.In this study,we developed an antioxidant scaffold by incorporating natural silk fibroin(SF)and kartogenin(KGN)-loaded liposomes(SF-Lipo@KGN).The scaffold demonstrated appropriate pore size,connectivity,and water absorption and the sustained release of KGN was achieved through the encapsulation of liposomes.In vitro experiments revealed that the SF-Lipo@KGN scaffolds exhibited excellent biocompatibility,as evidenced by enhanced cell adhesion,migration,and proliferation of chondrocytes.The SF-Lipo@KGN scaffolds were found to stimulate cartilage matrix synthesis through the activation of the nuclear factor erythroid-2-related factor 2/heme oxygenase-1 antioxidant signaling pathway.In vivo experiments demonstrated the effective promotion of articular cartilage regeneration by the SF-Lipo@KGN scaffolds,which enhanced extracellular matrix anabolism and restored the intrinsic redox homeostasis.Overall,this study successfully developed biomimetic KGN-loaded scaffolds that restore cartilage redox homeostasis,indicating promising prospects for cartilage tissue engineering.

Selenium-modified bone cement promotes osteoporotic bone defect repair in ovariectomized rats by restoring GPx1-mediated mitochondrial antioxidant functions

Over-accumulation of reactive oxygen species(ROS)causes mitochondrial dysfunction and impairs the osteogenic potential of bone marrow-derived mesenchymal stem cells(BMMSCs).Selenium(Se)protects BMMSCs from oxidative stress-induced damage;however,it is unknown whether Se supplementation can promote the repair of osteoporotic bone defects by rescuing the impaired osteogenic potential of osteoporotic BMMSCs(OP-BMMSCs).In vitro treatment with sodium selenite(Na_(2)SeO_(3))successfully improved the osteogenic differentiation of OP-BMMSCs,as demonstrated by increased matrix mineralization and up-regulated osteogenic genes expression.More importantly,Na_(2)SeO_(3) restored the impaired mitochondrial functions of OP-BMMSCs,significantly up-regulated glutathione peroxidase 1(GPx1)expression and attenuated the intracellular ROS and mitochondrial superoxide.Silencing of Gpx1 completely abrogated the protective effects of Na_(2)SeO_(3) on mitochondrial functions of OP-BMMSCs,suggesting the important role of GPx1 in protecting OP-BMMSCs from oxidative stress.We further fabricated Se-modified bone cement based on silk fibroin and calcium phosphate cement(SF/CPC).After 8 weeks of implantation,Se-modified bone cement significantly promoted bone defect repair,evidenced by the increased new bone tissue formation and enhanced GPx1 expression in ovariectomized rats.These findings revealed that Se supplementation rescued mitochondrial functions of OP-BMMSCs through activation of the GPx1-mediated antioxidant pathway,and more importantly,supplementation with Se in SF/CPC accelerated bone regeneration in ovariectomized rats,representing a novel strategy for treating osteoporotic bone fractures or defects.