Anti-EGFR ScFv functionalized exosomes delivering LPCAT1 specific siRNAs for inhibition of lung cancer brain metastases.

Brain metastasis (BM) is one of the leading causes of cancer-related deaths in patients with advanced non-small cell lung cancer (NSCLC). However, limited treatments are available due to the presence of the blood-brain barrier (BBB). Upregulation of lysophosphatidylcholine acyltransferase 1 (LPCAT1) in NSCLC has been found to promote BM. Conversely, downregulating LPCAT1 significantly suppresses the proliferation and metastasis of lung cancer cells. In this study, we firstly confirmed significant upregulation of LPCAT1 in BM sites compared to primary lung cancer by analyzing scRNA dataset. We then designed a delivery system based on a single-chain variable fragment (scFv) targeting the epidermal growth factor receptor (EGFR) and exosomes derived from HEK293T cells to enhance cell-targeting capabilities and increase permeability. Next, we loaded LPCAT1 siRNA (siLPCAT1) into these engineered exosomes (exoscFv). This novel scFv-mounted exosome successfully crossed the BBB in an animal model and delivered siLPCAT1 to the BM site. Silencing LPCAT1 efficiently arrested tumor growth and inhibited malignant progression of BM in vivo without detectable toxicity. Overall, we provided a potential platform based on exosomes for RNA interference (RNAi) therapy in lung cancer BM.

Prediction of preoperative microvascular invasion by dynamic radiomic analysis based on contrast-enhanced computed tomography.

PURPOSE: Microvascular invasion (MVI) is a common complication of hepatocellular carcinoma (HCC) surgery, which is an important predictor of reduced surgical prognosis. This study aimed to develop a fully automated diagnostic model to predict pre-surgical MVI based on four-phase dynamic CT images. METHODS: A total of 140 patients with HCC from two centers were retrospectively included (training set, n = 98; testing set, n = 42). All CT phases were aligned to the portal venous phase, and were then used to train a deep-learning model for liver tumor segmentation. Radiomics features were extracted from the tumor areas of original CT phases and pairwise subtraction images, as well as peritumoral features. Lastly, linear discriminant analysis (LDA) models were trained based on clinical features, radiomics features, and hybrid features, respectively. Models were evaluated by area under curve (AUC), accuracy, sensitivity, specificity, positive and negative predictive values (PPV and NPV). RESULTS: Overall, 86 and 54 patients with MVI- (age, 55.92 ± 9.62 years; 68 men) and MVI+ (age, 53.59 ± 11.47 years; 43 men) were included. Average dice coefficients of liver tumor segmentation were 0.89 and 0.82 in training and testing sets, respectively. The model based on radiomics (AUC = 0.865, 95% CI: 0.725-0.951) showed slightly better performance than that based on clinical features (AUC = 0.841, 95% CI: 0.696-0.936). The classification model based on hybrid features achieved better performance in both training (AUC = 0.955, 95% CI: 0.893-0.987) and testing sets (AUC = 0.913, 95% CI: 0.785-0.978), compared with models based on clinical and radiomics features (p-value < 0.05). Moreover, the hybrid model also provided the best accuracy (0.857), sensitivity (0.875), and NPV (0.917). CONCLUSION: The classification model based on multimodal intra- and peri-tumoral radiomics features can well predict HCC patients with MVI.

Profibrogenic macrophage-targeted delivery of mitochondrial protector via exosome formula for alleviating pulmonary fibrosis.

Pulmonary fibrosis (PF) is a devastating lung disease with limited treatment options. During this pathological process, the profibrogenic macrophage subpopulation plays a crucial role, making the characterization of this subpopulation fundamentally important. The present study revealed a positive correlation between pulmonary macrophages with higher mitochondrial mass (Mømitohigh) and fibrosis. Among the Mømitohigh subpopulation of CD206+ M2, characterized by higher expression of dynamin 1-like (Drp1), as determined by flow cytometry and RNA-seq analysis, a therapeutic intervention was developed using an exosome-based formula composed of pathfinder and therapeutics. A pathfinder exosome called "exosomeMMP19 (ExoMMP19)", was constructed to display matrix metalloproteinase-19 (MMP19) on the surface to locally break down the excessive extracellular matrix (ECM) in the fibrotic lung. A therapeutic exosome called "exosome therapeutics (ExoTx)", was engineered to display D-mannose on the surface while encapsulating siDrp1 inside. Prior delivery of ExoMMP19 degraded excessive ECM and thus paved the way for ExoTx to be delivered into Mømitohigh, where ExoTx inhibited mitochondrial fission and alleviated PF. This study has not only identified Mømitohigh as profibrotic macrophages but it has also provided a potent strategy to reverse PF via a combination of formulated exosomes.

Geometric constraint-triggered collagen expression mediates bacterial-host adhesion.

Cells living in geometrically confined microenvironments are ubiquitous in various physiological processes, e.g., wound closure. However, it remains unclear whether and how spatially geometric constraints on host cells regulate bacteria-host interactions. Here, we reveal that interactions between bacteria and spatially constrained cell monolayers exhibit strong spatial heterogeneity, and that bacteria tend to adhere to these cells near the outer edges of confined monolayers. The bacterial adhesion force near the edges of the micropatterned monolayers is up to 75 nN, which is ~3 times higher than that at the centers, depending on the underlying substrate rigidities. Single-cell RNA sequencing experiments indicate that spatially heterogeneous expression of collagen IV with significant edge effects is responsible for the location-dependent bacterial adhesion. Finally, we show that collagen IV inhibitors can potentially be utilized as adjuvants to reduce bacterial adhesion and thus markedly enhance the efficacy of antibiotics, as demonstrated in animal experiments.

Spatiotemporal Modulated Scaffold for Endogenous Bone Regeneration via Harnessing Sequentially Released Guiding Signals.

The design of a scaffold that can regulate the sequential differentiation of bone marrow mesenchymal stromal cells (BMSCs) according to the endochondral ossification (ECO) mechanism is highly desirable for effective bone regeneration. In this study, we successfully fabricated a dual-networked composite hydrogel composed of gelatin and hyaluronic acid (termed GCDH-M), which can sequentially release chondroitin sulfate (CS) and magnesium/silicon (Mg/Si) ions to provide spatiotemporal guidance for chondrogenesis, angiogenesis, and osteogenesis. The fast release of CS is from the GCDH hydrogel, and the sustained releases of Mg/Si ions are from poly(lactide-co-glycolide) microspheres embedded in the hydrogel. There is a difference in the release rates between CS and ions, resulting in the ability for the fast release of CS and sustained release of ions. The dual networks between the modified gelatin and hyaluronic acid via covalent bonding and host-guest interactions render the hydrogel with some dynamic feature to meet the differentiation development of BMSCs laden inside the hydrogel, i.e., transforming into a chondrogenic phenotype, further to a hypertrophic phenotype and eventually to an osteogenic phenotype. As evidenced by the results of in vitro and in vivo evaluations, this GCDH-M composite hydrogel was proved to be able to create an optimal microenvironment for embedded BMSCs responding to the sequential guiding signals, which aligns with the rhythm of the ECO process and ultimately boosts bone regeneration. The promising outcome achieved with this innovative hydrogel system sheds light on novel scaffold design targeting bone tissue engineering.

Exosome-Based Mitochondrial Delivery of circRNA mSCAR Alleviates Sepsis by Orchestrating Macrophage Activation.

Sepsis is one of the most common causes of death, which is closely related to the uncontrolled systemic inflammation. Dysregulation of M1 macrophage polarization is the primary contributor to serious inflammation. In this study, it is revealed that the murine homologue of circRNA SCAR (steatohepatitis-associated circRNA ATP5B regulator), denoted as circRNA mSCAR hereafter, decreases in the macrophages of septic mice, which correlates with the excessive M1 polarization. To restore circRNA mSCAR in mitochondria, exosomes encapsulated with circRNA mSCAR are further electroporated with poly-D-lysine-graft-triphenylphosphine (TPP-PDL), and thus TPP-PDL facilitates the bound circRNA delivered into mitochondria when the exosomes engulf by the recipient cells. In in vivo septic mouse model and in vitro cell model, it is shown that the exosome-based mitochondria delivery system delivers circRNA mSCAR into mitochondria preferentially in the macrophages, favoring macrophage polarization toward M2 subtype. Accordingly, the systemic inflammation is attenuated by exosome-based mitochondrial delivery of circRNA mSCAR, together with alleviated mortality. Collectively, the results uncover the critical role of circRNA mSCAR in sepsis, and provide a promising approach to attenuate sepsis via exosome-based mitochondrial delivery of circRNA mSCAR.

Catch bond-inspired hydrogels with repeatable and loading rate-sensitive specific adhesion.

Biological receptor-ligand adhesion governed by mammalian cells involves a series of mechanochemical processes that can realize reversible, loading rate-dependent specific interfacial bonding, and even exhibit a counterintuitive behavior called catch bonds that tend to have much longer lifetimes when larger pulling forces are applied. Inspired by these catch bonds, we designed a hydrogen bonding-meditated hydrogel made from acrylic acid-N-acryloyl glycinamide (AA-NAGA) copolymers and tannic acids (TA), which formed repeatable specific adhesion to polar surfaces in an ultra-fast and robust way, but hardly adhered to nonpolar materials. It demonstrated up to five-fold increase in shear adhesive strength and interfacial adhesive toughness with external loading rates varying from 5 to 500 mm min-1. With a mechanochemical coupling model based on Monte Carlo simulations, we quantitatively revealed the nonlinear dependence of rate-sensitive interfacial adhesion on external loading, which was in good agreement with the experimental data. Likewise, the developed hydrogels were biocompatible, possessed antioxidant and antibacterial properties and promoted wound healing. This work not only reports a stimuli-responsive hydrogel adhesive suitable for multiple biomedical applications, but also offers an innovative strategy for bionic designs of smart hydrogels with loading rate-sensitive specific adhesion for various emerging areas including flexible electronics and soft robotics.

"All-in-One" Exosome Engineering Strategy for Effective Therapy of Familial Hypercholesterolemia.

Exosomes serve as a promising therapeutic nanoplatform. However, the exosomes produced by donor cells are a heterogeneous group, with only a small portion having high therapeutic efficacy. Specific isolation of the subpopulation with high efficacy is important for lowering the dose and minimizing toxicity. In this study, we loaded target mRNA and displayed specific Flag in engineered exosomes simultaneously. Briefly, the donor cells were transfected with plasmid expressing a fusion protein Flag-TCS-PTGFRN-CTSL-MCP, namely, exosome sorter. During biogenesis, the RNA-binding motif MCP can specifically bind with MS2-containing RNA and sort the target RNA into the lumen of exosomes. Anti-Flag magnetic beads can capture and thus purify the engineered exosomes via recognition of the Flag on the surface of exosomes. After purification, the Flag could be cleaved by thrombin treatment while MCP can be separated from the fusion protein by CTSL autocleavage upon exosome acidification, minimizing the side effects and augmenting the therapeutic effects. By the proof-of-concept experiment, the exosome sorter-based "all-in-one" strategy was confirmed effective in both the encapsulation of therapeutic mRNA (Ldlr-MS2) into exosomes and the subsequent purification. The purified Ldlr-MS2-containing exosomes had much higher efficacy in alleviating atherosclerosis, in comparison with the bulk exosomes, confirming the advantage of the proposed "all-in-one" strategy.

ROS triggered local delivery of stealth exosomes to tumors for enhanced chemo/photodynamic therapy.

BACKGROUND: Exosomes are recognized as effective platforms for targeted delivery for their high physicochemical stability and biocompatibility. However, most of the exosomes are inevitably and rapidly cleared by mononuclear phagocytic system (MPS) during cancer therapy. How to engineer exosome to enhance the delivery efficiency is being intensively explored. In this study, we have constructed mPEG2000-TK-CP05 decorated exosomes as effective delivery platforms to achieve enhanced photodynamic/chemical cancer therapy. RESULTS: Exosomes were coated with CP05-TK-mPEG2000, in which CP05 is a peptide with high affinity to exosomal CD63 and TK could be cleaved by ROS. The resulted exosomes, namely stealth Exo, were electroporated to load RB (photosensitizer Rose Bengal) and Dox (Doxorubicin). We verified that the Stealth Exo@RB (Stealth Exo additionally loaded with RB) could escape MPS while accumulate in the tumor region efficiently in the xenograft model when laser irradiation conducted locally. Additionally, we revealed that the Stealth Exo serves as an efficient platform for Dox delivery. Dox, together with the RB mediated photodynamic therapy induce tumor cell damage synergistically in the tumor region. Moreover, the proposed switchable stealth exosomes minimized the dose of toxic Dox and thus allowed robust tumor immune response. CONCLUSIONS: Our results indicated that the proposed Stealth Exo greatly improves both the accessibility and efficiency of drug delivery, with minimal chemical or genetic engineering. The proposed Stealth Exo serve as a promising and powerful drug delivery nanoplatform in cancer treatment.

Controlled magnesium ion delivery system for in situ bone tissue engineering.

Magnesium cation (Mg2+) has been an emerging therapeutic agent for inducing vascularized bone regeneration. However, the therapeutic effects of current magnesium (Mg) -containing biomaterials are controversial due to the concentration- and stage-dependent behavior of Mg2+. Here, we first provide an overview of biochemical mechanism of Mg2+ in various concentrations and suggest that 2-10 mM Mg2+in vitro may be optimized. This review systematically summarizes and discusses several types of controlled Mg2+ delivery systems based on polymer-Mg composite scaffolds and Mg-containing hydrogels, as well as their design philosophy and several parameters that regulate Mg2+ release. Given that the continuous supply of Mg2+ may prevent biomineral deposition in the later stage of bone regeneration and maturation, we highlight the controlled delivery of Mg2+ based dual- or multi-ions system, especially for the hierarchical therapeutic ion release system, which shows enhanced biomineralization. Finally, the remaining challenges and perspectives of Mg-containing biomaterials for future in situ bone tissue engineering are discussed as well.

Stent Selection in Preoperative Biliary Drainage for Patients With Operable Pancreatic Cancer Receiving Neoadjuvant Therapy: A Meta-Analysis and Systematic Review.

With the increasing use of neoadjuvant therapy (NAT) in patients with pancreatic cancer to reduce tumor burden on prognosis, preoperative biliary drainage (PBD) is becoming increasingly necessary. The aim of this study was to summarize the latest evidence and compare the clinical efficacy of metal stents (MS) and plastic stents (PS) in patients undergoing neoadjuvant therapy for operable pancreatic cancer. Eligible studies were searched in PubMed, Embase and Cochrane Library from their inception to September 2021. In this study, RevMan 5.4 was used to perform the analyses. Two randomized controlled trials (RCTs) and six retrospective studies with 316 patients were included. All patients had pancreatic cancer and received NAT before surgical resection. Meta-analysis showed that the rate of endoscopic reintervention in MS (26/143, 18%) group was lower than that of PS (122/153, 80%) group (P < 0.05). The rate of stent-related complications in MS group was lower (18/118, 15%) than that of PS (52/117, 44%) group (P = 0.02). But there were no significant differences in operative time, operative blood loss, overall postoperative complications, postoperative hospitalization days and total medical costs between the two groups. For operable pancreatic cancer patients undergoing NAT surgery, MS was preferred over PS in terms of the incidence of endoscopic reintervention and stent-related complications. More clinical trials are needed in the future to confirm these data with higher levels of evidence.

Catalpol modulating the crosstalking between mesenchymal stromal cells and macrophages via paracrine to enhance angiogenesis and osteogenesis.

Due to the inflammatory responses associated with defect occurrence and materials implantation, immunoregulation has emerged as a promising strategy to enhance bone regeneration. It has been widely reported that a material could facilitate osteogenesis if it can guide macrophages to anti-inflammatory M2 phenotype, vice versa, a substrate will influence macrophage phenotype if it is osteoinductive. However, few studies have looked into the intercellular crosstalking directly. Herein, the compound catalpol was selected for its multiple functions to study the interactions between bone marrow mesenchymal stromal cells (BMSCs) and macrophages. This iridoid glucoside exhibits excellent anti-inflammatory and osteoinductive activities. The effects of catalpol on mediating M1/M2 polarization of macrophages, inhibiting osteoclast differentiation, promoting osteogenesis and angiogenesis were systematically investigated to correlate the biological responses of BMSCs and macrophages. To extend its in vivo application, the catalpol was then loaded onto an electrospun polylactide/gelatin composite fibrous mesh and subcutaneously implanted to evaluate the local inflammation and ectopic osteogenesis. The results revealed that the functions of catalpol displayed in modulating cellular behaviors are via cell paracrine to strengthen intercellular crosstalking, hence demonstrating that catalpol itself could serve as a promising bioactive stimulator for bone tissue engineering.

Role of Adipose Tissue Derived Exosomes in Metabolic Disease.

Adipose tissues perform physiological functions such as energy storage and endocrine, whose dysfunction will lead to severe metabolic disorders. Accumulating evidences show that exosomes can meditate communications between different tissues by transporting nucleic acids, proteins and other biological factors. More importantly, exosomes secreted by adipose tissue function as critical contributing factors that elucidate specific mechanisms in metabolic disturbance such as obesity, adipose inflammation and diabetes etc. Adipose tissue is the major source of circulating exosomal miRNAs. miRNA secreted from adipose tissues not only altered in patients with metabolic disease, but also result in an increase in metabolic organ talk. Here we have reviewed the latest progress on the role of adipose tissue derived exosomes roles in metabolic disorders. Moreover, the current obstacles hindering exosome-based therapeutic strategies have also been discussed.

A real-world study of infectious complications of venetoclax combined with decitabine or azacitidine in adult acute myeloid leukemia.

PURPOSE: The purpose of this study was to identify the incidence, sites and main pathogens, and risk factors for infectious complications occurring in patients with adult acute myeloid leukemia (AML) during the first course of venetoclax combined with decitabine or azacitidine. METHODS: A retrospective cohort analysis was performed of 81 patients with AML older than 14 years who received the first cycle of venetoclax combined with a hypomethylating agent (HMA) between March 2018 and March 2021 at our institution. Infectious complications, if any, were documented. RESULTS: Among a total of 81 cases of AML, 59 (72.8%) patients occurred infections, including fever without an identifiable source (28.8%), clinically documented infections (40.7%), and microbiologically documented infections (30.5%). The most commonly isolated organism in culture was Candida albicans, followed by Klebsiella pneumonia, and Pseudomonas aeruginosa. The 4-week and 8-week mortality rates were 3.7% and 7.4%, respectively. In multivariate analysis, a high proportion of blasts in bone marrow, decreased hemoglobin level, and fever with or without a documented infection at baseline were significant independent risk factors for infectious complications. CONCLUSION: Compared with conventional chemotherapy, the incidence of infectious complications of venetoclax combined with decitabine or azacitidine significantly decreased. Pretreatment high leukemia burden and fever were independent risk factors for infections.

Construction of multifunctional cell aggregates in angiogenesis and osteogenesis through incorporating hVE-cad-Fc-modified PLGA/ß-TCP microparticles for enhancing bone regeneration.

Multicellular aggregates have been widely utilized for regenerative medicine; however, the heterogeneous structure and undesired bioactivity of cell-only aggregates hinder their clinical translation. In this study, we fabricated an innovative kind of microparticle-integrated cellular aggregate with multifunctional activities in angiogenesis and osteogenesis, by combining stem cells from human exfoliated deciduous teeth (SHEDs) and bioactive composite microparticles. The poly(lactide-co-glycolide) (PLGA)-based bioactive microparticles (PTV microparticles) were ∼15 µm in diameter, with dispersed ß-tricalcium phosphate (ß-TCP) nanoparticles and surface-modified vascular endothelialcadherin fusion protein (hVE-cad-Fc). After co-culturing with microparticles in U-bottomed culture plates, SHEDs could firmly attach to the microparticles with a homogeneous distribution. The PTV microparticle-integrated SHED aggregates (PTV/SHED aggregates) showed significant positive CD31 and ALP expression, as well as the significantly upregulated osteogenesis makers (Runx2, ALP, and OCN) and angiogenesis makers (Ang-1 and CD31), compared with PLGA, PLGA/ß-TCP (PT) and PLGA/hVE-cad-Fc (PV) microparticle-integrated SHED aggregates. Finally, in mice, 3 mm calvarial defects filled with the PTV microparticle-integrated SHED aggregates achieved abundant vascularized neo-bone regeneration within 4 weeks. Overall, we believe that these multifunctional PTV/SHED aggregates could be used as modules for bottom-up regenerative medicine, and provide a promising method for vascularized bone regeneration.

Adoptive transfer of metabolically reprogrammed macrophages for atherosclerosis treatment in diabetic ApoE -/- mice.

Atherosclerosis is characterized by inflammation in the arterial wall, which is known to be exacerbated by diabetes. Therapeutic repression of inflammation is a promising strategy for treating atherosclerosis. In this study, we showed that diabetes aggravated atherosclerosis in apolipoproteinE knockout (ApoE -/-) mice, in which increased expression of long-chain acyl-CoA synthetase 1 (Acsl1) in macrophages played an important role. Knockdown of Acsl1 in macrophages (Mφ shAcsl1 ) reprogrammed macrophages to an anti-inflammatory phenotype, especially under hyperglycemic conditions. Injection of Mφ shAcsl1 reprogrammed macrophages into streptozotocin (STZ)-induced diabetic ApoE -/- mice (ApoE -/-+ STZ) alleviated inflammation locally in the plaque, liver and spleen. Consistent with the reduction in inflammation, plaques became smaller and more stable after the adoptive transfer of reprogrammed macrophages. Taken together, our findings indicate that increased Acsl1 expression in macrophages play a key role in aggravated atherosclerosis of diabetic mice, possibly by promoting inflammation. Adoptive transfer of Acsl1 silenced macrophages may serve as a potential therapeutic strategy for atherosclerosis.

Bioinspired porous microspheres for sustained hypoxic exosomes release and vascularized bone regeneration.

Exosomes derived from mesenchymal stem cells (MSCs) have demonstrated regenerative potential for cell-free bone tissue engineering, nevertheless, certain challenges, including the confined therapeutic potency of exosomes and ineffective delivery method, are still persisted. Here, we confirmed that hypoxic precondition could induce enhanced secretion of exosomes from stem cells from human exfoliated deciduous teeth (SHEDs) via comprehensive proteomics analysis, and the corresponding hypoxic exosomes (H-Exo) exhibited superior potential in promoting cellular angiogenesis and osteogenesis via the significant up-regulation in focal adhesion, VEGF signaling pathway, and thyroid hormone synthesis. Then, we developed a platform technology enabling the effective delivery of hypoxic exosomes with sustained release kinetics to irregular-shaped bone defects via injection. This platform is based on a simple adsorbing technique, where exosomes are adsorbed onto the surface of injectable porous poly(lactide-co-glycolide) (PLGA) microspheres with bioinspired polydopamine (PDA) coating (PMS-PDA microspheres). The PMS-PDA microspheres could effectively adsorb exosomes, show sustained release of H-Exo for 21 days with high bioactivity, and induce vascularized bone regeneration in 5-mm rat calvarial defect. These findings indicate that the hypoxic precondition and PMS-PDA porous microsphere-based exosome delivery are efficient in inducing tissue regeneration, hence facilitating the clinical translation of exosome-based therapy.

Brain functional connectivities that mediate the association between childhood traumatic events, and adult mental health and cognition.

BACKGROUND: Childhood traumatic events are risk factors for psychopathology, but large-scale studies of how childhood traumatic events relate to mental health and cognition in adulthood, and how the brain is involved, are needed. METHODS: The associations between childhood traumatic events (such as abuse and neglect, and defined by the 'Childhood Trauma' questions in the UK Biobank database) and brain functional connectivity, mental health problems, and cognitive performance were investigated by a univariate correlation analysis with 19,535 participants aged 45-79 from the UK Biobank dataset. The results were replicated with 17,747 independent participants in the second release from the same dataset. FINDINGS: Childhood traumatic events were significantly associated with mental health problems in adulthood including anxiety (r=0.19, p<1.0 × 10-323), depression (r=0.21, p<1.0 × 10-323), and self-harm (r=0.24, p<1.0 × 10-323), and with adult cognitive performance including fluid intelligence (r=-0.05, p=2.8 × 10-10) and prospective memory (r=-0.04, p=6.8 × 10-8). Functional connectivities of the medial and lateral temporal cortex, the precuneus, the medial orbitofrontal cortex; and the superior, middle and inferior prefrontal cortex extending back to precentral regions were negatively correlated with the childhood traumatic events (FDR corrected, p<0.01). These lower functional connectivities significantly mediated the associations between childhood traumatic events and addiction, anxiety, depression and well-being (all p<1.0 × 10-3), and cognitive performance. The association between childhood traumatic events and behavioural measures and functional connectivity were confirmed in a replication with different participants in the second release of the UK Biobank dataset. INTERPRETATION: Childhood traumatic events are strongly associated with adult mental health problems mediated by brain functional connectivities in brain areas involved in executive function, emotion, face processing, and memory. This understanding may help with prevention and treatment. FUNDING: Funding was provided by the National Key R&D Program of China (No. 2018YFC1312900 and No. 2019YFA0709502).

Dental resin composites with improved antibacterial and mineralization properties via incorporating zinc/strontium-doped hydroxyapatite as functional fillers.

This study intends to improve the antibacterial and mineralization performance of photocurable dental resin composites (DRCs) to reduce the possibility of repair failure caused by secondary caries. To the end, functionalized hydroxyapatite (HAp), including Zn-doped (Zn/HAp) and Sr-doped HAp (Sr/HAp), were added into the bisphenol A glycidyl methacrylate and triethylene glycol dimethacrylate mixture, providing the DRCs with antibacterial and mineralization capacity, respectively. By controlling the total amount of inorganic filler at 70 wt%, these HAp powders were introduced into the resin matrix with barium glass powder (BaGP), while the ratios of HAp to aGP varied from 0:70 to 8:62. And the 8 wt% of HAp could be pure HAp, Zn/HAp, Sr/HAp, or Zn/HAp +Sr/HAp in different ratios (i.e. 2:6, 4:4, 6:2). Though the fillers varied, the obtained DRCs displayed similar micro-morphology, flexural strength (∼110 MPa) and modulus (∼7 GPa), and Vickers hardness (∼65). When the doping amounts of Sr2+/Zn2+reached 15 mol% of Ca2+in the Sr/HAp and Zn/HAp, the DRCs displayed a high antibacterial activity by killing ∼95%Staphylococcus aureus, and induced rich mineral deposition on surface in simulated body fluid. The incorporation of the Zn/HAp and Sr/HAp into the DRCs did not cause significant cytotoxicity, with L929 fibroblasts remaining >99% viability as cultured in extracts made from the DRCs. Therein, the DRC preparations containing both Zn/HAp and Sr/HAp have achieved improvements in both the biomineralization and antibacterial performance, as well as, having sufficient mechanical properties and excellent biocompatibility for dental restoration.

Exosomes derived from reparative M2-like macrophages prevent bone loss in murine periodontitis models via IL-10 mRNA.

BACKGROUND: Periodontitis is characterized by progressive inflammation and alveolar bone loss resulting in tooth loss finally. Macrophages including pro-inflammatory M1-like macrophages and reparative M2-like macrophages play a vital role in inflammation and tissue homeostasis in periodontitis. Among them, reparative M2-like macrophages have been shown to promote tissue repair and prevent bone loss. However, the mechanism of reparative M2 macrophages-induced osteoprotective effect remains elusive. RESULTS: Exosomes from reparative M2-like macrophages (M2-Exos) were isolated and identified successfully. M2-Exos could promote bone marrow stromal cells (BMSCs) osteogenic differentiation while suppressing bone marrow derived macrophage (BMDM) osteoclast formation, and prohibit pathological alveolar bone resorption because of the intercellular communication via exosomes. High expression level of IL-10 mRNA was detected not only in reparative M2-like macrophages but also in M2-Exos. Meanwhile, IL-10 expression level in BMSCs or BMDM was also upregulated significantly after co-culturing with M2-Exos in a concentration-dependent manner. In vitro, recombinant IL-10 proteins had the ability to selectively promote osteogenic differentiation of BMSCs and hinder osteoclast differentiation of BMDM. Moreover, after treatment with M2-Exos and IL-10R antibody together, the capacity of promoting osteogenesis and suppressing osteoclastogenesis of M2-Exos was significantly reversed. In vivo experiments further showed that M2-Exos reduced alveolar bone resorption in mice with periodontitis via IL-10/IL-10R pathway. CONCLUSION: In conclusion, our results demonstrate that the reparative M2-like macrophages could promote osteogenesis while inhibiting osteoclastogenesis in vitro as well as protect alveolar bone against resorption in vivo significantly. M2-Exos could upregulate the IL-10 cytokines expression of BMSCs and BMDM via delivering exosomal IL-10 mRNA to cells directly, leading to activation of the cellular IL-10/IL-10R pathway to regulate cells differentiation and bone metabolism. These results might partly account for the mechanism of osteoprotective effect of reparative M2-like macrophages and provide a novel perspective and a potential therapeutic approach on improving alveolar resorption by M2-Exos.