Advances in regenerative medicine applications of tetrahedral framework nucleic acid-based nanomaterials: an expert consensus recommendation

With the emergence of DNA nanotechnology in the 1980s, self-assembled DNA nanostructures have attracted considerable attention worldwide due to their inherent biocompatibility, unsurpassed programmability, and versatile functions. Especially promising nanostructures are tetrahedral framework nucleic acids(t FNAs), first proposed by Turberfield with the use of a one-step annealing approach. Benefiting from their various merits, such as simple synthesis, high reproducibility, structural stability, cellular internalization, tissue permeability, and editable functionality, t FNAs have been widely applied in the biomedical field as threedimensional DNA nanomaterials. Surprisingly, t FNAs exhibit positive effects on cellular biological behaviors and tissue regeneration,which may be used to treat inflammatory and degenerative diseases. According to their intended application and carrying capacity,t FNAs could carry functional nucleic acids or therapeutic molecules through extended sequences, sticky-end hybridization,intercalation, and encapsulation based on the Watson and Crick principle. Additionally, dynamic t FNAs also have potential applications in controlled and targeted therapies. This review summarized the latest progress in pure/modified/dynamic t FNAs and demonstrated their regenerative medicine applications. These applications include promoting the regeneration of the bone,cartilage, nerve, skin, vasculature, or muscle and treating diseases such as bone defects, neurological disorders, joint-related inflammatory diseases, periodontitis, and immune diseases.

Bioengineering breakthroughs:The impact of stem cell models on advanced therapy medicinal product development

The burgeoning field of bioengineering has witnessed significant strides due to the advent of stem cell models,particularly in their application in advanced therapy medicinal products(ATMPs).In this review,we examine the multifaceted impact of these developments,emphasizing the potential of stem cell models to enhance the sophistication of ATMPs and to offer alternatives to animal testing.Stem cell-derived tissues are particularly promising because they can reshape the preclinical landscape by providing more physiologically relevant and ethically sound platforms for drug screening and disease modelling.We also discuss the critical challenges of reproducibility and accuracy in measurements to ensure the integrity and utility of stem cell models in research and application.Moreover,this review highlights the imperative of stem cell models to align with regulatory standards,ensuring using stem cells in ATMPs translates into safe and effective clinical therapies.With regulatory approval serving as a gateway to clinical adoption,the collaborative efforts between scientists and regulators are vital for the progression of stem cell applications from bench to bedside.We advocate for a balanced approach that nurtures innovation within the framework of rigorous validation and regulatory compliance,ensuring that stem cell-base solutions are maximized to promote public trust and patient health in ATMPs.

Hepatoprotective effects of baicalein against CCl 4-induced acute liver injury in mice

AIM:To investigate the hepatoprotective effect of baicalein against carbon tetrachloride(CCl 4)-induced liver damage in mice.METHODS:Mice were orally administered with baicalein after CCl 4 injection,and therapeutic baicalein was given twice a day for 4 d.The anti-inflammation effects of baicalein were assessed directly by hepatic histology and serum alanine aminotranferease and aspartate aminotransferase measurement.Proliferating cell nuclear antigen was used to evaluate the effect of baicalein in promoting hepatocyte proliferation.Serum interleukin(IL)-6,IL-1β and tumor necrosis factor-α(TNF-α) levels were measured by enzyme-linked immunosorbent assay and liver IL-6,TNF-α,transforming growth factor-α(TGF-α),hepatocyte growth factor(HGF) and epidermal growth factor(EGF) genes expression were determined by quantitative real-time polymerase chain reaction.RESULTS:CCl4-induced acute liver failure model offers a survival benefit in baicalein-treated mice.The data indicated that the mRNA levels of IL-6 and TNF-α significantly increased within 12 h after CCl 4 treatment in baicalein administration groups,but at 24,48 and 72 h,the expression of IL-6 and TNF-α was kept at lower levels compared with the control.The expression of TGF-α,HGF and EGF was enhanced dramatically in baicalein administration group at 12,24,48 and 72 h.Furthermore,we found that baicalein significantly elevated the serum level of TNF-α and IL-6 at the early phase,which indicated that baicalein could facilitate the initiating events in liver regeneration.CONCLUSION:Baicalein may be a therapeutic candidate for acute liver injury.Baicalein accelerates liver regeneration by regulating TNF-α and IL-6 mediated pathways.

Total flavonoids of hawthorn leaves promote motor function recovery via inhibition of apoptosis after spinal cord injury

Flavonoids have been reported to have therapeutic potential for spinal cord injury.Hawthorn leaves have abundant content and species of total flavonoids,and studies of the effects of the total flavonoids of hawthorn leaves on spinal cord injury have not been published in or outside China.Therefore,Sprague-Dawley rats were used to establish a spinal cord injury model by Allen's method.Rats were intraperitoneally injected with 0.2 m L of different concentrations of total flavonoids of hawthorn leaves(5,10,and 20 mg/kg)after spinal cord injury.Injections were administered once every 6 hours,three times a day,for 14 days.After treatment with various concentrations of total flavonoids of hawthorn leaves,the Basso,Beattie,and Bresnahan scores and histological staining indicated decreases in the lesion cavity and number of apoptotic cells of the injured spinal cord tissue;the morphological arrangement of the myelin sheath and nerve cells tended to be regular;and the Nissl bodies in neurons increased.The Basso,Beattie,and Bresnahan scores of treated spinal cord injury rats were increased.Western blot assays showed that the expression levels of pro-apoptotic Bax and cleaved caspase-3 were decreased,but the expression level of the anti-apoptotic Bcl-2 protein was increased.The improvement of the above physiological indicators showed a dose-dependent relationship with the concentration of total flavonoids of hawthorn leaves.The above findings confirm that total flavonoids of hawthorn leaves can reduce apoptosis and exert neuroprotective effects to promote the recovery of the motor function of rats with spinal cord injury.This study was approved by the Ethics Committee of the Guangxi Medical University of China(approval No.201810042)in October 2018.

Pathological mechanisms and therapeutic outlooks for arthrofibrosis

Arthrofibrosis is a fibrotic joint disorder that begins with an inflammatory reaction to insults such as injury,surgery and infection.Excessive extracellular matrix and adhesions contract pouches,bursae and tendons,cause pain and prevent a normal range of joint motion,with devastating consequences for patient quality of life.Arthrofibrosis affects people of all ages,with published rates varying.The risk factors and best management strategies are largely unknown due to a poor understanding of the pathology and lack of diagnostic biomarkers.However,current research into the pathogenesis of fibrosis in organs now informs the understanding of arthrofibrosis.The process begins when stress signals stimulate immune cells.The resulting cascade of cytokines and mediators drives fibroblasts to differentiate into myofibroblasts,which secrete fibrillar collagens and transforming growth factor-β(TGF-β).Positive feedback networks then dysregulate processes that normally terminate healing processes.We propose two subtypes of arthrofibrosis occur:active arthrofibrosis and residual arthrofibrosis.In the latter the fibrogenic processes have resolved but the joint remains stiff.The best therapeutic approach for each subtype may differ significantly.Treatment typically involves surgery,however,a pharmacological approach to correct dysregulated cell signalling could be more effective.Recent research shows that myofibroblasts are capable of reversing differentiation,and understanding the mechanisms of pathogenesis and resolution will be essential for the development of cell-based treatments.Therapies with significant promise are currently available,with more in development,including those that inhibit TGF-βsignalling and epigenetic modifications.This review focuses on pathogenesis of sterile arthrofibrosis and therapeutic treatments.

Protein microarray analysis of cytokine expression changes in distal stumps after sciatic nerve transection

A large number of chemokines,cytokines,other trophic factors and the extracellular matrix molecules form a favorable microenvironment for peripheral nerve regeneration.This microenvironment is one of the major factors for regenerative success.Therefore,it is important to investigate the key molecules and regulators affecting nerve regeneration after peripheral nerve injury.However,the identities of specific cytokines at various time points after sciatic nerve injury have not been determined.The study was performed by transecting the sciatic nerve to establish a model of peripheral nerve injury and to analyze,by protein microarray,the expression of different cytokines in the distal nerve after injury.Results showed a large number of cytokines were up-regulated at different time points post injury and several cytokines,e.g.,ciliary neurotrophic factor,were downregulated.The construction of a protein-protein interaction network was used to screen how the proteins interacted with differentially expressed cytokines.Kyoto Encyclopedia of Genes and Genomes pathway and Gene ontology analyses indicated that the differentially expressed cytokines were significantly associated with chemokine signaling pathways,Janus kinase/signal transducers and activators of transcription,phosphoinositide 3-kinase/protein kinase B,and notch signaling pathway.The cytokines involved in inflammation,immune response and cell chemotaxis were up-regulated initially and the cytokines involved in neuronal apoptotic processes,cell-cell adhesion,and cell proliferation were up-regulated at 28 days after injury.Western blot analysis showed that the expression and changes of hepatocyte growth factor,glial cell line-derived neurotrophic factor and ciliary neurotrophic factor were consistent with the results of protein microarray analysis.The results provide a comprehensive understanding of changes in cytokine expression and changes in these cytokines and classical signaling pathways and biological functions during Wallerian degeneration,as well as a basis for potential treatments of peripheral nerve injury.The study was approved by the Institutional Animal Care and Use Committee of the Chinese PLA General Hospital,China(approval number:2016-x9-07)in September 2016.

Safety of intrathecal injection of Wharton's jellyderived mesenchymal stem cells in amyotrophic lateral sclerosis therapy

Animal experiments have confirmed that mesenchymal stem cells can inhibit motor neuron apoptosis and inflammatory factor expression and increase neurotrophic factor expression. Therefore, mesenchymal stem cells have been shown to exhibit prospects in the treatment of amyotrophic lateral sclerosis. However, the safety of their clinical application needs to be validated. To investigate the safety of intrathecal injection of Wharton's jelly-derived mesenchymal stem cells in amyotrophic lateral sclerosis therapy, 43 patients(16 females and 27 males, mean age of 57.3 years) received an average dose of 0.42 × 106 cells/kg through intrathecal administration at the cervical, thoracic or lumbar region depending on the clinical symptoms. There was a 2 month interval between two injections. The adverse events occurring during a 6-month treatment period were evaluated. No adverse events occurred. Headache occurred in one case only after first injection of stem cells. This suggests that intrathecal injection of Wharton's Jelly-derived mesenchymal stem cells is well tolerated in patients with amyotrophic lateral sclerosis. This study was approved by the Bioethical Committee of School of Medicine, University of Warmia and Mazury in Olsztyn, Poland(approval No. 36/2014 and approval No. 8/2016). This study was registered with the ClinicalTrials.gov(identifier: NCT02881476)on August 29, 2016.

Bioinformatic analysis of cytokine expression in the proximal and distal nerve stumps after peripheral nerve injury

In our previous study,we investigated the dynamic expression of cytokines in the distal nerve stumps after peripheral nerve injury using microarray analysis,which can characterize the dynamic expression of proteins.In the present study,we used a rat model of right sciatic nerve transection to examine changes in the expression of cytokines at 1,7,14 and 28 days after injury using protein microarray analysis.Interleukins were increased in the distal nerve stumps at 1–14 days post nerve transection.However,growth factors and growth factor-related proteins were mainly upregulated in the proximal nerve stumps.The P-values of the inflammatory response,apoptotic response and cell-cell adhesion in the distal stumps were higher than those in the proximal nerve stumps,but the opposite was observed for angiogenesis.The number of cytokines related to axons in the distal stumps was greater than that in the proximal stumps,while the percentage of cytokines related to axons in the distal stumps was lower than that in the proximal nerve stumps.Visualization of the results revealed the specific expression patterns and differences in cytokines in and between the proximal and distal nerve stumps.Our findings offer potential therapeutic targets and should help advance the development of clinical treatments for peripheral nerve injury.Approval for animal use in this study was obtained from the Animal Ethics Committee of the Chinese PLA General Hospital on September 7,2016(approval No.2016-x9-07).

High drug loading hydrophobic cross-linked dextran microspheres as novel drug delivery systems for the treatment of osteoarthritis

Drug delivery via intra-articular(IA)injection has proved to be effective in osteoarthritis(OA)therapy,limited by the drug efficiency and short retention time of the drug delivery systems(DDSs).Herein,a series of modified cross-linked dextran(Sephadex,S0)was fabricated by respectively grafting with linear alkyl chains,branched alkyl chains or aromatic chain,and acted as DDSs after ibuprofen(Ibu)loading for OA therapy.This DDSs expressed sustained drug release,excellent anti-inflammatory and chondroprotective effects both in IL-1βinduced chondrocytes and OA joints.Specifically,the introduction of a longer hydrophobic chain,particularly an aromatic chain,distinctly improved the hydrophobicity of S0,increased Ibu loading efficiency,and further led to significantly improving OA therapeutic effects.Therefore,hydrophobic microspheres with greatly improved drug loading ratio and prolonged degradation rates show great potential to act as DDSs for OA therapy.

Isolated cryptococcal osteomyelitis of the ulna in an immunocompetent patient:A case report

BACKGROUND Cryptococcal osteomyelitis is a bone infection caused by cryptococcus.As an opportunistic infection,bone cryptococcosis usually occurs in patients with immunodeficiency diseases or in those undergoing immunosuppressive therapy and often displays characteristics of disseminated disease.Isolated cryptococcal osteomyelitis is extremely unusual in immunocompetent person.The pathogenic fungus often invades vertebrae,femur,tibia,rib,clavicle,pelvis,and humerus,but the ulna is a rare target.CASE SUMMARY A 79-year-old woman complaining of chronic pain,skin ulceration and a sinus on her right forearm was admitted,and soon after was diagnosed with cryptococcal osteomyelitis in the right ulna.Unexpectedly,she was also found to have apparently normal immunity.After treatment with antifungal therapy combined with surgery debridement,the patient’s osteomyelitis healed with a satisfactory outcome.CONCLUSION Although rare,cryptococcal osteomyelitis should be considered in the differential diagnosis of osteolytic lesions even in immunocompetent patients,and good outcomes can be expected if early definitive diagnosis and etiological treatment are established.

Genome-wide identification and spatiotemporal expression profiling of zinc finger SWIM domain-containing protein family genes

The biological function of the novel zinc-finger SWIM domain-containing protein family(ZSWIM)during embryonic development remains elusive.Here,we conducted a genome-wide analysis to explore the evolutionary processes of the ZSWIM gene family members in mice,Xenopus tropicalis,zebrafish,and humans.We identified nine putative ZSWIM genes in the human and mouse genome,eight in the Xenopus genome,and five in the zebrafish genome.Based on multiple sequence alignment,three members,ZSWIM5,ZSWIM6,and ZSWIM8,demonstrated the highest homology across all four species.Using available RNA sequencing(RNAseq)data,ZSWIM genes were found to be widely expressed across different tissues,with distinct tissuespecific properties.To identify the functions of the ZSWIM protein family during embryogenesis,we examined temporal and spatial expression patterns of zswim family genes in Xenopus embryos.Quantitative real-time polymerase chain reaction(qRT-PCR)revealed that each member had a distinct expression profile.Whole-mount in situ hybridization showed that both zswim1 and zswim3 were maternally expressed genes;zswim5 and zswim6were expressed throughout embryogenesis and displayed dynamic expression in the brain,eyes,somite,and bronchial arch at the late tailbud stages;zswim7 was detected in the eye area;zswim8 showed a dynamic expression pattern during the tailbud stages,with expression detected in the brain,eyes,and somite;zswim9 was faintly expressed throughout embryonic development.This study provides a foundation for future research to delineate the functions of ZSWIM gene members.

Trim21 depletion alleviates bone loss in osteoporosis via activation of YAP1/β-catenin signaling

Despite the diverse roles of tripartite motif(Trim)-containing proteins in the regulation of autophagy,the innate immune response,and cell differentiation,their roles in skeletal diseases are largely unknown.We recently demonstrated that Trim21 plays a crucial role in regulating osteoblast(OB)differentiation in osteosarcoma.However,how Trim21 contributes to skeletal degenerative disorders,including osteoporosis,remains unknown.First,human and mouse bone specimens were evaluated,and the results showed that Trim21 expression was significantly elevated in bone tissues obtained from osteoporosis patients.Next,we found that global knockout of the Trim21 gene(KO,Trim2^(1-/-))resulted in higher bone mass compared to that of the control littermates.We further demonstrated that loss of Trim21 promoted bone formation by enhancing the osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)and elevating the activity of OBs;moreover,Trim21 depletion suppressed osteoclast(OC)formation of RAW264.7 cells.In addition,the differentiation of OCs from bone marrow-derived macrophages(BMMs)isolated from Trim21^(-/-)and Ctsk-cre;Trim21^(f/f)mice was largely compromised compared to that of the littermate control mice.Mechanistically,YAP1/β-catenin signaling was identified and demonstrated to be required for the Trim21-mediated osteogenic differentiation of BMSCs.More importantly,the loss of Trim21 prevented ovariectomy(OVX)-and lipopolysaccharide(LPS)-induced bone loss in vivo by orchestrating the coupling of OBs and OCs through YAP1 signaling.Our current study demonstrated that Trim21 is crucial for regulating OB-mediated bone formation and OC-mediated bone resorption,thereby providing a basis for exploring Trim21 as a novel dual-targeting approach for treating osteoporosis and pathological bone loss.

Cellular Mechanism of Mouse Atrial Development

During the development of mammalian heart, the left and right atria play an important role in cardiovascular circulation. The embryonic atrium is mainly formed by the differentiation of progenitor cells and the proliferation of cardiomyocytes, while the postnatal atrium is primarily shaped by the increase in the volume of cardiomyocytes. Cell proliferation and differentiation of atrial development is the basis for its functions such as “blood reservoir” and “supplementary pump”. Deep understanding the cellular mechanism of atrial development is imperative to explore the causes of common congenital arrhythmia heart diseases such as atrial fibrillation. We used genetically engineered mouse reproduction knowledge, lineage tracing method based on CreloxP system, molecular biology and immunofluorescence technology to track the cardiomyocyte lineage of Nppa-GFP mouse line with stereo fluorescence microscope and ultra-high-speed confocal microscope. Besides the atrium of Nppa-CreER;Rosa26 tdTomato mouse was examined during embryonic (E10.5 - E18.5) and postnatal (P0, P3, P5, P7, P14, P28, P8w) stage. Immunofluorescence results revealed that Nppa-positive cells labeled TNNI3-positive cardiomyocytes and protruded into the atrial cavity at the beginning of E11.5 - E12.0 and during subsequent development to form Nppa-positive myocardial trabeculae. Thick comb-shaped myocardium was observed after birth, and we suspect that this was particularly important for the normal contractile activity and pumping function of the atrium. Additionally, non-single origin of Nppa-positive trabecular myocardiocytes were revealed through Tamoxifen-induced lineage tracing experiment. Our findings reveal proliferation dynamics and non-comprehensive fate decisions of cardiomyocytes that produce the distinct architecture of the atrium chamber.

Extracellular matrix from human umbilical cordderived mesenchymal stem cells as a scaffold for peripheral nerve regeneration

The extracellular matrix,which includes collagens,laminin,or fibronectin,plays an important role in peripheral nerve regeneration.Recently,a Schwann cell-derived extracellular matrix with classical biomaterial was used to mimic the neural niche.However,extensive clinical use of Schwann cells remains limited because of the limited origin,loss of an autologous nerve,and extended in vitro culture times.In the present study,human umbilical cord-derived mesenchymal stem cells（h UCMSCs）,which are easily accessible and more proliferative than Schwann cells,were used to prepare an extracellular matrix.We identified the morphology and function of h UCMSCs and investigated their effect on peripheral nerve regeneration.Compared with a non-coated dish tissue culture,the h UCMSC-derived extracellular matrix enhanced Schwann cell proliferation,upregulated gene and protein expression levels of brain-derived neurotrophic factor,glial cell-derived neurotrophic factor,and vascular endothelial growth factor in Schwann cells,and enhanced neurite outgrowth from dorsal root ganglion neurons.These findings suggest that the h UCMSC-derived extracellular matrix promotes peripheral nerve repair and can be used as a basis for the rational design of engineered neural niches.

An aptamer-driven DNA nanodevice for improved delivery of synthetic immunostimulants

Efficient delivery of therapeutics to immune cells remains a formidable challenge for cancer immunotherapy.In this work,we demonstrate that an aptamer-driven DNA nanodevice,constructed through linkage of a synthetic immunostimulant(Toll-like receptor 9 agonist:CpG motif)to an aptamer,could significantly enhance the immunostimulatory activity by facilitating the uptake and retention of therapeutics in macrophages.Systemic administration of the DNA nanodevice results in efficient tumor growth inhibition in both breast cancer and melanoma mouse models.Our studies suggest that the DNA nanodevice leads to reeducation of tumor-associated macrophages and ultimately to reversing the tumor immune microenvironment.The strategy for aptamer-mediated and vehicle-free delivery of immunostimulatory oligonucleotides provides a potential platform for cancer immunotherapy.

Biophysical-driven piezoelectric and aligned nanofibrous scaffold promotes bone regeneration by re-establishing physiological electrical microenvironment

The initial healing stages of bone fracture is a complex physiological process involving a series of spatially and temporally overlapping events,including pathogen clearance,immunological modulation,and osteogenesis.In this study,we have developed a piezoelectric and aligned nanofibrous scaffold composed of ZnO@PCL/PVDF with multiple antibacterial,immunomodulatory,and osteogenic effects using electrospinning technology.This scaffold’s piezoelectric signal output under ultrasound(US)control can be similar to the physiological electrical signals of healthy bone tissue,creating a truly biomimetic electrical microenvironment in the bone defect.In vitro studies have shown that ZnO@PCL/PVDF scaffold significantly enhances the proliferation,migration,and osteogenic differentiation of MC3T3-E1 cells under piezoelectric drive provided by ultrasound.Furthermore,the scaffold exhibits inhibitory effects on the growth of E.coli and S.aureus,as well as the ability to induce M2 macrophage polarization,indicating potent antibacterial and immunomodulatory properties.In vivo experiments demonstrated that the ZnO@PCL/PVDF scaffold can accelerate the repair of mandibular defects in rats,effectively inhibit bacterial colonization,and reduce inflammatory responses.Altogether,this study confirms that the newly developed ZnO@PCL/PVDF scaffold effectively promotes bone repair by truly mimicking the endogenous electrical microenvironment and precisely regulating the temporospatial disorders of initial bone healing,thus providing a simple and effective solution for bone defects.

Role of integrin b1 and tenascin C mediate TGF-SMAD2/3 signaling in chondrogenic differentiation of BMSCs induced by type I collagen hydrogel

Cartilage defects may lead to severe degenerative joint diseases.Tissue engineering based on type I collagen hydrogel that has chondrogenic potential is ideal for cartilage repair.However,the underlying mechanisms of chondrogenic differentiation driven by type I collagen hydrogel have not been fully clarified.Herein,we explored potential collagen receptors and chondrogenic signaling pathways through bioinformatical analysis to investigate the mechanism of collagen-induced chondrogenesis.Results showed that the super enhancer-related genes induced by collagen hydrogel were significantly enriched in the TGF-b signaling pathway,and integrin-b1(ITGB1),a receptor of collagen,was highly expressed in bone marrow mesenchymal stem cells(BMSCs).Further analysis showed genes such as COL2A1 and Tenascin C(TNC)that interacted with ITGB1 were significantly enriched in extracellular matrix(ECM)structural constituents in the chondrogenic induction group.Knockdown of ITGB1 led to the downregulation of cartilage-specific genes(SOX9,ACAN,COL2A1),SMAD2 and TNC,as well as the downregulation of phosphorylation of SMAD2/3.Knockdown of TNC also resulted in the decrease of cartilage markers,ITGB1 and the SMAD2/3 phosphorylation but overexpression of TNC showed the opposite trend.Finally,in vitro and in vivo experiments confirmed the involvement of ITGB1 and TNC in collagen-mediated chondrogenic differentiation and cartilage regeneration.In summary,we demonstrated that ITGB1 was a crucial receptor for chondrogenic differentiation of BMSCs induced by collagen hydrogel.It can activate TGF-SMAD2/3 signaling,followed by impacting TNC expression,which in turn promotes the interaction of ITGB1 and TGF-SMAD2/3 signaling to enhance chondrogenesis.These may provide concernful support for cartilage tissue engineering and biomaterials development.

The potent osteo-inductive capacity of bioinspired brown seaweed-derived carbohydrate nanofibrous three-dimensional scaffolds

This study aimed to investigate the osteo-inductive capacity of a fucoidan polysaccharide network derived from brown algae on human adipose-derived stem cells(HA-MSCs)for bone regeneration.The physiochemical properties of the scaffold including surface morphology,surface chemistry,hydrophilicity,mechanical stiffness,and porosity were thoroughly characterized.Both in vitro and in vivo measurements implied a superior cell viability,proliferation,adhesion,and osteo-inductive performance of obtained scaffolds compared to using specific osteogenic induction medium with increased irregular growth of calcium crystallites,which mimic the structure of natural bones.That scaffold was highly biocompatible and suitable for cell cultures.Various examinations,such as quantification of mineralization,alkaline phosphatase,gene expression,and immunocytochemical staining of pre-osteocyte and bone markers confirmed that HAD-MSCs differentiate into osteoblasts,even without an osteogenic induction medium.This study provides evidence for the positive relationship and synergistic effects between the physical properties of the decellularized seaweed scaffold and the chemical composition of fucoidan in promoting the osteogenic differentiation of HA-MSCs.Altogether,the natural matrices derived from brown seaweed offers a sustainable,cost-effective,non-toxic bioinspired scaffold and holds promise for future clinical applications in orthopedics.

Chemical screen identifies a geroprotective role of quercetin in premature aging

Aging increases the risk of various diseases. The main goal of aging research is to find therapies that attenuate aging and alleviate aging-related diseases. In this study, we screened a natural product library for geroprotective compounds using Werner syndrome (WS) human mesenchymal stem cells (hMSCs), a premature aging model that we recently established. Ten candidate compounds were identified and quercetin was investigated in detail due to its leading effects. Mechanistic studies revealed that quercetin alleviated senescence via the enhancement of cell proliferation and restoration of heterochromatin architecture in WS hMSCs. RNA-sequencing analysis revealed the transcriptional commonalities and differences in the geroprotective effects by quercetin and Vitamin C. Besides WS hMSCs, quercetin also attenuated cellular senescence in Hutchinson-Gilford progeria syndrome (HGPS) and physiological-aging hMSCs. Taken together, our study identifies quercetin as a geroprotective agent against accelerated and natural aging in hMSCs, providing a potential therapeutic intervention for treating age-associated disorders.

Injectable ECM hydrogel for delivery of BMSCs enabled full-thickness meniscus repair in an orthotopic rat model

Meniscal injuries have poor intrinsic healing capability and are associated with the development of osteoarthritis.Decellularized meniscus extracellular matrix(mECM)has been suggested to be efficacious for the repair of meniscus defect.However,main efforts to date have been focused on the concentration,crosslinking density and anatomical region dependence of the mECM hydrogels on regulation of proliferation and differentiation of adult mesenchymal stem cells(MSCs)in vitro 2D or 3D culture.A systematic investigation and understanding of the effect of mECM on encapsulated MSCs response and integrative meniscus repair by in vivo rat subcutaneous implantation and orthotopic meniscus injury model will be highly valuable to explore its potential for clinical translation.In this study,we investigated the in situ delivery of rat BMSCs in an injectable mECM hydrogel to a meniscal defect in a SD rat model.Decellularized mECM retained essential proteoglycans and collagens,and significantly upregulated expression of fibrochondrogenic markers by BMSCs versus collagen hydrogel alone in vitro 3D cell culture.When applied to an orthotopic model of meniscal injury in SD rat,mECM is superior than collagen I scaffold in reduction of osteophyte formation and prevention of joint space narrowing and osteoarthritis development as evidenced by histology and micro-CT analysis.Taken together,these results indicate mECM hydrogel is a highly promising carrier to deliver MSCs for long-term repair of meniscus tissue,while preventing the development of osteoarthritis.