Exosomes derived from BMSCs in osteogenic differentiation promote type H blood vessel angiogenesis through miR-150-5p mediated metabolic reprogramming of endothelial cells.

Osteogenesis is tightly coupled with angiogenesis spatiotemporally. Previous studies have demonstrated that type H blood vessel formed by endothelial cells with high expression of CD31 and Emcn (CD31hi Emcnhi ECs) play a crucial role in bone regeneration. The mechanism of the molecular communication around CD31hi Emcnhi ECs and bone mesenchymal stem cells (BMSCs) in the osteogenic microenvironment is unclear. This study indicates that exosomes from bone mesenchymal stem cells with 7 days osteogenic differentiation (7D-BMSCs-exo) may promote CD31hi Emcnhi ECs angiogenesis, which was verified by tube formation assay, qRT-PCR, Western blot, immunofluorescence staining and µCT assays etc. in vitro and in vivo. Furthermore, by exosomal miRNA microarray and WGCNA assays, we identified downregulated miR-150-5p as the most relative hub gene coupling osteogenic differentiation and type H blood vessel angiogenesis. With bioinformatics assays, dual luciferase reporter experiments, qRT-PCR and Western blot assays, SOX2(SRY-Box Transcription Factor 2) was confirmed as a novel downstream target gene of miR-150-5p in exosomes, which might be a pivotal mechanism regulating CD31hi Emcnhi ECs formation. Additionally, JC-1 immunofluorescence staining, Western blot and seahorse assay results showed that the overexpression of SOX2 could shift metabolic reprogramming from oxidative phosphorylation (OXPHOS) to glycolysis to enhance the CD31hi Emcnhi ECs formation. The PI3k/Akt signaling pathway might play a key role in this process. In summary, BMSCs in osteogenic differentiation might secrete exosomes with low miR-150-5p expression to induce type H blood vessel formation by mediating SOX2 overexpression in ECs. These findings might reveal a molecular mechanism of osteogenesis coupled with type H blood vessel angiogenesis in the osteogenic microenvironment and provide a new therapeutic target or cell-free remedy for osteogenesis impaired diseases.

EF1α-associated protein complexes affect dendritic spine plasticity by regulating microglial phagocytosis in Fmr1 knock-out mice.

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability. There is no specific treatment for FXS due to the lack of therapeutic targets. We report here that Elongation Factor 1α (EF1α) forms a complex with two other proteins: Tripartite motif-containing protein 3 (TRIM3) and Murine double minute (Mdm2). Both EF1α-Mdm2 and EF1α-TRIM3 protein complexes are increased in the brain of Fmr1 knockout mice as a result of FMRP deficiency, which releases the normal translational suppression of EF1α mRNA and increases EF1α protein levels. Increased EF1α-Mdm2 complex decreases PSD-95 ubiquitination (Ub-PSD-95) and Ub-PSD-95-C1q interaction. The elevated level of TRIM3-EF1α complex is associated with decreased TRIM3-Complement Component 3 (C3) complex that inhibits the activation of C3. Both protein complexes thereby contribute to a reduction in microglia-mediated phagocytosis and dendritic spine pruning. Finally, we created a peptide that disrupts both protein complexes and restores dendritic spine plasticity and behavioural deficits in Fmr1 knockout mice. The EF1α-Mdm2 and EF1α-TRIM3 complexes could thus be new therapeutic targets for FXS.

Small-molecule targeting AMPA-mediated excitotoxicity has therapeutic effects in mouse models for multiple sclerosis.

While most research and treatments for multiple sclerosis (MS) focus on autoimmune reactions causing demyelination, it is possible that neurodegeneration precedes the autoimmune response. Hence, glutamate receptor antagonists preventing excitotoxicity showed promise in MS animal models, though blocking glutamate signaling prevents critical neuronal functions. This study reports the discovery of a small molecule that prevents AMPA-mediated excitotoxicity by targeting an allosteric binding site. A machine learning approach was used to screen for small molecules targeting the AMPA receptor GluA2 subunit. The lead candidate has potent effects in restoring neurological function and myelination while reducing the immune response in experimental autoimmune encephalitis and cuprizone MS mouse models without affecting basal neurotransmission or learning and memory. These findings facilitate development of a treatment for MS with a different mechanism of action than current immune modulatory drugs and avoids important off-target effects of glutamate receptor antagonists. This class of MS therapeutics could be useful as an alternative or complementary treatment to existing therapies.

Serum amyloid P component (SAP) modulates antidepressant effects through promoting membrane insertion of the serotonin transporter.

Serum amyloid P component (SAP) is a universal constituent of human amyloid deposits including those in Alzheimer's disease. SAP has been observed to be elevated in patients with depression, and higher SAP levels are associated with better response to the antidepressant escitalopram. The mechanisms underlying these clinical observations remain unclear. We examined the effect of SAP on serotonin transporter (SERT) expression and localization using Western blot, confocal microscopy, and positron emission tomography with the radioligand [11C]DASB. We also investigated the effect of SAP on treatment response to escitalopram in mice with the forced swim test (FST), a classical behaviour paradigm to assess antidepressant effects. SAP reduced [11C]DASB binding as an index of SERT levels, consistent with Western blots showing decreased total SAP protein because of increased protein degradation. In conjunction with the global decrease in SERT levels, SAP also promotes VAMP-2 mediated SERT membrane insertion. SAP levels are correlated with behavioural despair and SSRI treatment response in mice with FST. In MDD patients, the SAP and membrane SERT levels are correlated with response to SSRI treatment. SAP has complex effects on SERT levels and localization, thereby modulating the effect of SSRIs, which could partially explain clinical variability in antidepressant treatment response. These results add to our understanding of the mechanism for antidepressant drug action, and with further work could be of clinical utility.

Fabrication of BMP-2-peptide-Deferoxamine- and QK-peptide-functionalized nanoscaffolds and their application for bone defect treatment.

The microenvironment in the healing process of large bone defects requires suitable conditions to promote osteogenesis and angiogenesis. Coaxial electrospinning is a mature method in bone tissue engineering (BTE) and allows functional modification. Appropriate modification methods can be used to improve the bioactivity of scaffolds for BTE. In this study, coaxial electrospinning with QK peptide (a Vascular endothelial growth factor mimetic peptide) and BMP-2 peptide-DFO (BD) was performed to produce double-modified PQBD scaffolds with vascularizing and osteogenic features. The morphology of coaxially electrospun scaffolds was verified by scanning electron microscopy (SEM) and transmission electron microscopy. Laser scanning confocal microscopy and Fourier transform infrared spectroscopy confirmed that BD covalently bound to the surface of the P and PQ scaffolds. In vitro, the PQBD scaffold promoted the adhesion and proliferation of bone marrow stromal cells (BMSCs). Both QK peptide and BD showed sustainable release and preservation of biological activity, enhancing the osteogenic differentiation of BMSCs and the migration of human umbilical vein endothelial cells and promoting angiogenesis. The combined ability of these factors to promote osteogenesis and angiogenesis is superior to that of each alone. In vivo, the PQBD scaffold was implanted into the bone defect, and after 8 weeks, the defect area was almost completely covered by new bone tissue. Histology showed more mature bone tissue and more blood vessels. PQBD scaffolds promote both angiogenesis and osteogenesis, offering a promising approach to enhance bone regeneration in the treatment of large bone defects.

The GR-FKBP51 interaction modulates fear memory but not spatial or recognition memory.

The glucocorticoid receptor (GR) forms a protein complex with FKBP51 that is increased in post-traumatic stress disorder (PTSD) and by fear conditioned learning. Disrupting the GR-FKBP51 complex with a synthetic peptide can block the storage or retrieval of fear conditioned memories, which could be a novel approach to the alleviate fear associated memory in PTSD. However, a potential unacceptable side effect could be the impairment of other types of memory. Thus, we investigated the effect of disrupting the GR-FKBP51 complex on recognition memory using the novel object and displaced object recognition tasks, spatial memory in the Morris water maze, and on social interaction in Crawley's three-chamber social interaction test. We did not observe adverse effects on these other types of memory and conclude that the GR-FKBP51 interaction remains a promising target for treating psychiatric disorders characterized by unwanted aversive memories such as in PTSD.

Sex Differences in Dopamine Receptor Signaling in Fmr1 Knockout Mice: A Pilot Study.

Fragile X syndrome (FXS) is an X-chromosome-linked dominant genetic disorder that causes a variable degree of cognitive dysfunction and developmental disability. Current treatment is symptomatic and no existing medications target the specific cause of FXS. As with other X-linked disorders, FXS manifests differently in males and females, including abnormalities in the dopamine system that are also seen in Fmr1-knockout (KO) mice. We investigated sex differences in dopamine signaling in Fmr1-KO mice in response to L-stepholidine, a dopamine D1 receptor agonist and D2 receptor antagonist. We found significant sex differences in basal levels of phosphorylated protein kinase A (p-PKA) and glycogen synthase kinase (GSK)-3ß in wild type mice that were absent in Fmr1-KO mice. In wild-type mice, L-stepholidine increased p-PKA in males but not female mice, decreased p-GSK-3 in female mice and increased p-GSK-3 in male mice. Conversely, in Fmr1-KO mice, L-stepholidine increased p-PKA and p-GSK-3ß in females, and decreased p-PKA and p-GSK-3ß in males.

Hsa-circ-0007292 promotes the osteogenic differentiation of posterior longitudinal ligament cells via regulating SATB2 by sponging miR-508-3p.

Ossification of the posterior longitudinal ligament (OPLL) is a disorder with multiple pathogenic mechanisms and leads to different degrees of neurological symptoms. Recent studies have revealed that non-coding RNA (ncRNA), including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), could influence the development of OPLL. Nevertheless, the molecular mechanisms linking circular RNAs (circRNAs) and the progression of OPLL is still unknown. The current research explored the expression profiles of OPLL-related circRNAs by microarray analysis, and applied qRT-PCR to validate the results. Subsequently, we confirmed the upregulation of hsa_circ_0007292 in OPLL cells by qRT-PCR and validated the circular characteristic of hsa_circ_0007292 by Sanger sequencing. Fluorescence in situ hybridization (FISH) unveiled that hsa_circ_0007292 was predominantly located in the cytoplasm. Functionally, gain-of-function and loss-of-function experiments showed that hsa_circ_0007292 promoted the osteogenic differentiation of OPLL cells. Mechanistically, the interaction of hsa_circ_0007292 and miR-508-3p was predicted and validated by bioinformatics analysis, dual-luciferase reporter assays, and Ago2 RNA immunoprecipitation (RIP). Similarly, we validated the correlation between miR-508-3p and SATB2. Furthermore, rescue experiments were performed to prove that hsa_circ_0007292 acted as a sponge for miR-508-3p, and SATB2 was revealed to be the target gene of miR-508-3p. In conclusion, our research shows that hsa_circ_0007292 regulates OPLL progression by the miR-508-3p/SATB2 pathway. Our results indicate that hsa_circ_0007292 can be used as a promising therapeutic target for patients with OPLL.

Disrupting the α7nAChR-NR2A protein complex exerts antidepressant-like effects.

Major depressive disorder (MDD) is associated with significant morbidity and mortality. Most antidepressant medications target the serotonin and norepinephrine transporters, but a significant minority of patients do not respond to treatment and novel therapeutic targets are needed. We previously identified a protein complex composed of the α7 nicotinic acetylcholine receptor (nAChR) and NMDA glutamate receptors (NMDARs), through which α7nAChR upregulates NMDAR function. Disruption of the α7nAChR-NMDAR complex with an interfering peptide blocked α7nAChR-mediated upregulation of NMDAR function and cue-induced reinstatement of nicotine seeking in rat models of relapse. Here we report that disrupting the α7nAChR-NMDAR complex with the interfering peptide also has antidepressant-like effects in the forced swim test (FST), a common rat behaviour screening test for antidepressant effects. Furthermore, the interfering peptide significantly increases extracellular signal-regulated kinase (ERK) activity in the animals subjected to the FST. Our results provide a novel potential therapeutic target for the development of new antidepressant medications.

The PIF1-miR408-PLANTACYANIN repression cascade regulates light-dependent seed germination.

Light-dependent seed germination is a vital process for many seed plants. A decisive event in light-induced germination is degradation of the central repressor PHYTOCHROME INTERACTING FACTOR 1 (PIF1). The balance between gibberellic acid (GA) and abscisic acid (ABA) helps to control germination. However, the cellular mechanisms linking PIF1 turnover to hormonal balancing remain elusive. Here, employing far-red light-induced Arabidopsis thaliana seed germination as the experimental system, we identified PLANTACYANIN (PCY) as an inhibitor of germination. It is a blue copper protein associated with the vacuole that is both highly expressed in mature seeds and rapidly silenced during germination. Molecular analyses showed that PIF1 binds to the miR408 promoter and represses miR408 accumulation. This in turn posttranscriptionally modulates PCY abundance, forming the PIF1-miR408-PCY repression cascade for translating PIF1 turnover to PCY turnover during early germination. Genetic analysis, RNA-sequencing, and hormone quantification revealed that PCY is necessary and sufficient to maintain the PIF1-mediated seed transcriptome and the low-GA-high-ABA state. Furthermore, we found that PCY domain organization and regulation by miR408 are conserved features in seed plants. These results revealed a cellular mechanism whereby PIF1-relayed external light signals are converted through PCY turnover to internal hormonal profiles for controlling seed germination.

Ibrutinib alleviates LPS-induced neuroinflammation and synaptic defects in a mouse model of depression.

Previous studies have demonstrated a close association between an altered immune system and major depressive disorders, and inhibition of neuroinflammation may represent an alternative mechanism to treat depression. Recently, the anti-inflammatory activity of ibrutinib has been reported. However, the effect of ibrutinib on neuroinflammation-induced depression and its underlying mechanism has not been comprehensively studied. Therefore, we aimed to elucidate the potential anti-depressive role and mechanism of ibrutinib against neuroinflammation-induced depression and synaptic defects. Our results showed that ibrutinib treatment significantly reduced lipopolysaccharide (LPS)-induced depressive-like behaviors and neuroinflammation via inhibiting NF-kB activation, decreasing proinflammatory cytokine levels, and normalizing redox signaling and its downstream components, including Nrf2, HO-1, and SOD2, as well as glial cell activation markers, such as Iba-1 and GFAP. Further, ibrutinib treatment inhibited LPS-activated inflammasome activation by targeting NLRP3/P38/Caspase-1 signaling. Interestingly, LPS reduced the number of dendritic spines and expression of BDNF, and synaptic-related markers, including PSD95, snap25, and synaptophysin, were improved by ibrutinib treatment in the hippocampal area of the mouse brain. In conclusion, our findings suggest that ibrutinib can alleviate neuroinflammation and synaptic defects, suggesting it has antidepressant potential against LPS-induced neuroinflammation and depression.

A modular programmed biphasic dual-delivery system on 3D ceramic scaffolds for osteogenesis in vitro and in vivo.

Single-factor delivery is the most common characteristic of bone tissue engineering techniques. However, bone regeneration is a complex process requiring multiple factors and specialized release mechanisms. Therefore, the development of a dual-delivery system allowing for programmed release kinetics would be highly desirable. Improvement of the molarity and versatility of the delivery system has rarely been studied. Herein, we report the development of a novel, modular programmed biphasic dual-release system (SCB), carrying a BMP2 and an engineered collagen I-derived recognition motif (Stath-DGEA), with a self-remodification feature on hydroxyapatite (HA)-based materials. The SCB system was loaded onto an additive manufactured (AM) scaffold in order to evaluate its bifactor osteogenic potential and its biphasic release behavior. Further, the biomechanical properties of the scaffold were studied by using the fluid-structure interaction (FSI) method. Section fluorescent labeling revealed that the HA scaffold has a relatively higher density and efficiency. Additionally, the results of the release and inhibition experiment suggested that the SCB system could facilitate the sustained release of therapeutic levels of two factors during the initial stage of implantation, thereby exhibiting a rapid high-dose release pattern at a specific time point during the second stage. The FSI prediction model indicated that the scaffold provides an excellent biomimetic mechanical and fluid dynamic microenvironment to promote osteogenesis. Our results indicated that incorporation of BMP2 with Stath-DGEA in the biphasic SCB system could have a synergetic effect in promoting the adhesion, proliferation, and differentiation of bone marrow mesenchymal stem cells (BMSCs) in vitro, under staged stimulations. Further, in vivo studies in both ectopic and orthotopic rat models showed that the SCB system loaded onto an AM scaffold could enhance osteointegration and osteoinduction throughout the osteogenic process. Thus, the novel synthetic SCB system described herein used on an AM scaffold provides a biomimetic extracellular environment that enhances bone regeneration and is a promising multifunctional, dual-release platform.

Methylation-mediated down-regulation of microRNA-497-195 cluster confers osteogenic differentiation in ossification of the posterior longitudinal ligament of the spine via ADORA2A.

Aberrant expression of microRNAs (miRNAs) has been associated with spinal ossification of the posterior longitudinal ligament (OPLL). Our initial bioinformatic analysis identified differentially expressed ADORA2A in OPLL and its regulatory miRNAs miR-497 and miR-195. Hence, this study was conducted to clarify the functional relevance of miR-497-195 cluster in OPLL, which may implicate in Adenosine A2A (ADORA2A). PLL tissues were collected from OPLL and non-OPLL patients, followed by quantification of miR-497, miR-195 and ADORA2A expression. The expression of miR-497, miR-195 and/or ADORA2A was altered in posterior longitudinal ligament (PLL) cells, which then were stimulated with cyclic mechanical stress (CMS). We validated that ADORA2A was expressed highly, while miR-497 and miR-195 were down-regulated in PLL tissues of OPLL patients. miR-195 and miR-497 expression in CMS-treated PLL cells was restored by a demethylation reagent 5-aza-2'-deoxycytidine (AZA). Moreover, expression of miR-195 and miR-497 was decreased by promoting promoter CpG island methylation. ADORA2A was verified as the target of miR-195 and miR-497. Overexpression of miR-195 and miR-497 diminished expression of osteogenic factors in PLL cells by inactivating the cAMP/PKA signaling pathway via down-regulation of ADORA2A. Collectively, miR-497-195 cluster augments osteogenic differentiation of PLL cells by inhibiting ADORA2A-dependent cAMP/PKA signaling pathway.

The glucocorticoid receptor-FKBP51 complex contributes to fear conditioning and posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) can develop after exposure to severe psychological trauma, leaving patients with disabling anxiety, nightmares, and flashbacks. Current treatments are only partially effective, and development of better treatments is hampered by limited knowledge of molecular mechanisms underlying PTSD. We have discovered that the glucocorticoid receptor (GR) and FK506 binding protein 51 (FKBP51) form a protein complex that is elevated in PTSD patients compared with unaffected control subjects, subjects exposed to trauma without PTSD, and patients with major depressive disorder (MDD). The GR-FKBP51 complex is also elevated in fear-conditioned mice, an aversive learning paradigm that models some aspects of PTSD. Both PTSD patients and fear-conditioned mice had decreased GR phosphorylation, decreased nuclear GR, and lower expression of 14-3-3ε, a gene regulated by GR. We created a peptide that disrupts GR-FKBP51 binding and reverses behavioral and molecular changes induced by fear conditioning. This peptide reduces freezing time and increases GR phosphorylation, GR-FKBP52 binding, GR nuclear translocation, and 14-3-3ε expression in fear-conditioned mice. These experiments demonstrate a molecular mechanism contributing to PTSD and suggest that the GR-FKBP51 complex may be a diagnostic biomarker and a potential therapeutic target for preventing or treating PTSD.

The receptor-receptor interaction between mGluR1 receptor and NMDA receptor: a potential therapeutic target for protection against ischemic stroke.

Ischemic stroke is one of the leading causes of long-term disability worldwide. It arises when the blood flow to the brain is severely impaired, causing brain infarction. The current therapies for ischemic stroke are tissue plasminogen activator and mechanical thrombectomy, which re-establishes blood circulation to the brain but offers no neuroprotective effects. Excitotoxicity, particularly through the N-methyl-d-aspartate receptor (NMDAR), has been heavily implicated in the pathophysiology of brain infarction resulting from ischemic stroke. Here we investigated the interaction between NMDAR and metabotropic glutamate receptor 1 (mGluR1) as a novel target to develop potential neuroprotective agents for ischemic stroke. Through coimmunoprecipitation and affinity binding assay, we revealed that the interaction is mediated through 2 distinct sites on the mGluR1 C terminus. We then found that the disruption of mGluR1-GluN2A subunit of NMDAR (GluN2A) protected the primary mouse hippocampal neurons against NMDAR-mediated excitotoxicity and reversed the NMDAR-mediated regulation of ERK1/2 in rat hippocampal slices. The same protection was also observed in an animal model of ischemic stroke, alleviating brain infarction and yielding better motor recovery. These findings confirmed the existence of a receptor-receptor interaction between NMDAR and mGluR1, implicating this interconnection as a potential treatment target site for ischemic stroke.-Lai, T. K. Y., Zhai, D. Su, P., Jiang, A., Boychuk, J., Liu, F. The receptor-receptor interaction between mGluR1 receptor and NMDA receptor: a potential therapeutic target for protection against ischemic stroke.

Dually optimized polycaprolactone/collagen I microfiber scaffolds with stem cell capture and differentiation-inducing abilities promote bone regeneration.

Micro-nano based fibrous scaffolds have been extensively studied in regenerative medicine. Bone marrow stem cells (BMSCs) and BMP2-derived peptides, two other important components for tissue engineering, have been successfully used for bone regeneration. However, a scaffold that specifically captures BMSCs and delivers BMP2-derived peptides to promote osteogenic differentiation of enriched BMSCs has not been reported. In this study, a microfiber scaffold was constructed by coaxial electrospinning technology using a polyvinylpyrrolidone/bovine serum albumin/BMP2-derived peptide compound as the core solution and a polycaprolactone/collagen I compound as the shell solution. The scaffolds were further functionalized by covalent grafting of a BMSC affinity peptide (E7) to develop a dual drug release system for the delivery of the BMP2-derived peptide and E7. Structural analysis indicated that the microfibers had a uniform diameter and homogeneous core-shell structure. Fourier transform infrared spectroscopy (FTIR) revealed that E7 was covalently bonded onto the surface of the fibers. In vitro, the E7-modified scaffolds promoted the initial adhesion of BMSCs and were more favorable for BMSC survival. Furthermore, the BMP2-derived peptide loaded in the E7-modified scaffolds was released in a sustained manner and retained bioactivity, significantly improving the osteogenic differentiation of BMSCs. In vivo, scaffolds loaded with the BMP2-derived peptide and E7 (PCME scaffolds) led to enhanced new bone formation and defect closure in a rat calvarial defect model. Overall, the PCME scaffold simultaneously facilitated all three of the essential elements needed for bone tissue engineering, providing a promising method for bone regeneration.

A three-dimensional (3D) printed biomimetic hierarchical scaffold with a covalent modular release system for osteogenesis.

Hydroxyapatite (HA) ceramics are well known for their biocompatibility, bioactivity, and osteoconductive nature. However, limited hierarchical structure and lack of ease in modularity hinder the widespread application of conventional HA ceramics. By using three-dimensional printing (3DP) techniques with multiple materials, including HA, complex biological and mechanical architecture of natural organisms can be achieved through biomimetics. In this study, we designed an osteoid, biomimetic, hierarchical, porous HA ceramic 3D printed scaffold (3DPs). Further incorporation of a covalent, modular, controlled release system (CMR), based on Watson-Crick's complementary oligonucleotides, and was added to carry a bone morphogenetic protein-2 (BMP2) peptide. The choice of a HA biomimetic scaffold housing BMP2 protein fragments was selected to successfully promote osteogenesis both in vitro and in vivo. Scanning electron microscopy, micro-computed tomography analysis and computer fluid dynamics simulations of the 3DPs showed a uniform biomimetic hierarchical structure and an effective interior permeability. Active molecules were found bound with high stability and modular to the scaffold surface via the CMR system. After 7 days of incubation under physiological conditions, approximately 90% of active factors remained bound. Compared to control groups, the 3DPs-CMR-BMP2 group significantly enhanced cell proliferation and adhesion. Moreover, the 3DPs-CMR-BMP2 group exhibited more extensive and sustained osteogenic effects through upregulated expression of osteogenic factors and enhanced calcium deposition, as compared to study and control groups. Furthermore, ectopic osteogenesis and a critical calvarial defect model confirmed that the 3DPs-CMR-BMP2 group significantly promoted in vivo bone healing versus control. Thus, our results showed that biomimetic hierarchical 3DPs with a CMR system successfully promote cell proliferation, adhesion, differentiation and osteogenesis, on a continuous cycle. The biomimetic hierarchical 3DPs with a CMR system offers a promising multi-functional, bone substitute material for treatment of patients with bone defects.

Chitosan-Gelatin Scaffolds Incorporating Decellularized Platelet-Rich Fibrin Promote Bone Regeneration.

Platelet-rich fibrin (PRF), which functions as a growth factor carrier, has been extensively used to promote soft and hard tissue repair. However, whether decellularized PRF (DPRF) maintains its bioactive effects is unknown. Chitosan/gelatin(C/G) base scaffolds display appropriate biocompatibility and mechanical properties, but they lack biological activity. Thus, the incorporation of DPRF into the C/G scaffold can theoretically improve both the bioactivity of the C/G scaffold and the strength of PRF. In this study, DPRF was prepared using a method combining repeated freeze-thawing and enzymatic digestion. Also, DPRF-loaded chitosan-gelatin scaffolds (C/G/DPRF) were fabricated, using C/G scaffolds as controls. The osteogenic potential of scaffolds was investigated in vitro and in vivo. Compared with the C/G scaffold, C/G/DPRF had a larger pore size (280.8 ± 11.7 µm vs 235.0 ± 11.6 µm; P < 0.05), increased water uptake ratio (13.90 ± 0.09 vs 11.05 ± 0.10; P < 0.05), and similar porosity (90.50 ± 0.87 vs 90.65 ± 0.67; P > 0.05) but reduced compressive modulus (0.81 ± 0.02 MPa vs 1.17 ± 0.05 MPa; P < 0.05). In vitro, C/G/DPRF scaffolds accelerated attachment, proliferation, and osteogenesis-related marker expression of bone marrow stem cells. In vivo, C/G/DPRF scaffolds led to enhanced bone healing and defect closure in a rat calvarial defect model. Thus, we concluded that DPRF remains bioactive and the prepared C/G/DPRF scaffold is a promising material for bone regeneration.

Specific Alterations in Astrocyte Properties via the GluA2-GAPDH Complex Associated with Multiple Sclerosis.

There is strong evidence indicating neuroinflammation is an important mediator in multiple sclerosis (MS), with astrogliosis playing a significant role in this process. Surprisingly, astrocytes exert paradoxical roles during disease development, but the mechanisms remain unknown. Previously, we have reported that administering an interfering peptide (GluA2-G-Gpep) which specifically disrupts the GluA2-GAPDH interaction rescued neurological symptoms in the EAE mouse model of MS. In this study, we validated that the GluA2-GAPDH complex was elevated in LPS-induced primary reactive astrocytes, and GluA2-G-Gpep treatment significantly reduced GFAP expression levels in both EAE mice and reactive astrocytes. Further in vivo and in vitro analyses revealed that GluA2-G-Gpep administration normalized EAAT1 and EAAT2 expression, rescued compromised blood-brain barrier integrity via AQP4, promoted actin reorganization and changed mitochondrial dynamics. These alterations may partially be explained by changes in the nuclear GAPDH and p53 transcription pathways. Our findings provide critical implications for understanding the astrocyte properties regulated by GluA2-GAPDH associated with MS, and insights for novel treatment options targeting at astrocytes.

Sesamin inhibits IL-1ß-stimulated inflammatory response in human osteoarthritis chondrocytes by activating Nrf2 signaling pathway.

Sesamin, a bioactive component extracted from sesame, has been reported to exert anti-inflammatory and anti-oxidant effects. In this study, we evaluated the anti-inflammatory effects of sesamin on IL-1ß-stimulated human osteoarthritis chondrocytes and investigated the possible mechanism. Results demonstrated that sesamin treatment significantly inhibited PGE2 and NO production induced by IL-1ß. Sesamin inhibited MMP1, MMP3, and MMP13 production in IL-1ß-stimulated chondrocytes. Sesamin also inhibited IL-1ß-induced phosphorylation of NF-κB p65 and IκBα. Meanwhile, sesamin was found to up-regulate the expression of Nrf2 and HO-1. However, Nrf2 siRNA reversed the anti-inflammatory effects of sesamin. In conclusion, our results suggested that sesamin showed anti-inflammatory effects in IL-1ß-stimulated chondrocytes by activating Nrf2 signaling pathway.