Advanced glycation end products impair bone marrow mesenchymal stem cells osteogenesis in periodontitis with diabetes via FTO-mediated N6-methyladenosine modification of sclerostin.

BACKGROUND: Diabetes mellitus (DM) and periodontitis are two prevalent diseases with mutual influence. Accumulation of advanced glycation end products (AGEs) in hyperglycemia may impair cell function and worsen periodontal conditions. N6-methyladenosine (m6A) is an important post-transcriptional modification in RNAs that regulates cell fate determinant and progression of diseases. However, whether m6A methylation participates in the process of periodontitis with diabetes is unclear. Thus, we aimed to investigate the effects of AGEs on bone marrow mesenchymal stem cells (BMSCs), elucidate the m6A modification mechanism in diabetes-associated periodontitis. METHODS: Periodontitis with diabetes were established by high-fat diet/streptozotocin injection and silk ligation. M6A modifications in alveolar bone were demonstrated by RNA immunoprecipitation sequence. BMSCs treated with AGEs, fat mass and obesity associated (FTO) protein knockdown and sclerostin (SOST) interference were evaluated by quantitative polymerase chain reaction, western blot, immunofluorescence, alkaline phosphatase and Alizarin red S staining. RESULTS: Diabetes damaged alveolar bone regeneration was validated in vivo. In vitro experiments showed AGEs inhibited BMSCs osteogenesis and influenced the FTO expression and m6A level in total RNA. FTO knockdown increased the m6A levels and reversed the AGE-induced inhibition of BMSCs differentiation. Mechanically, FTO regulated m6A modification on SOST transcripts, and AGEs affected the binding of FTO to SOST transcripts. FTO knockdown accelerated the degradation of SOST mRNA in presence of AGEs. Interference with SOST expression in AGE-treated BMSCs partially rescued the osteogenesis by activating Wnt Signaling. CONCLUSIONS: AGEs impaired BMSCs osteogenesis by regulating SOST in an m6A-dependent manner, presenting a promising method for bone regeneration treatment of periodontitis with diabetes.

Increased serum α-tocopherol acetate mediated by gut microbiota ameliorates alveolar bone loss through the STAT3 signalling pathway in diabetic periodontitis.

AIM: To evaluate whether and how gut microbiota-meditated metabolites regulate alveolar bone homeostasis in diabetic periodontitis (DP). MATERIALS AND METHODS: Lactobacillus casei (L. casei) was employed as a positive modulator of gut microbiota in DP mice. The destruction of alveolar bone was evaluated. Untargeted metabolomics was conducted to screen out the pivotal metabolites. A co-housing experiment was conducted to determine the connection between the gut microbiota and alpha-tocopherol acetate (α-TA). α-TA was applied to DP mice to investigate its effect against alveolar bone loss. Human periodontal ligament cells (hPDLCs) and human gingival fibroblasts (HGFs) were extracted for the in vitro experiment. Transcriptomic analysis and immunohistochemistry were performed to detect the major affected signalling pathways. RESULTS: Positive regulation of the gut microbiota significantly attenuated alveolar bone loss and increased the serum α-TA level. The alteration in gut microbiota composition could affect the serum α-T (the hydrolysates of α-TA) level. α-TA could alleviate alveolar bone destruction in DP mice and α-T exert beneficial effects on hPDLCs and HGFs. Mechanistically, the STAT3 signalling pathway was the pivotal pathway involved in the protective role of α-TA. CONCLUSIONS: The gut microbiota-α-TA-STAT3 axis plays an important role in the regulation of diabetic alveolar bone homeostasis.

Oxidative stress state inhibits exosome secretion of hPDLCs through a specific mechanism mediated by PRMT1.

BACKGROUND AND OBJECTIVES: Periodontitis, the most common chronic inflammation characterized by persistent alveolar bone resorption in the periodontitis, affects almost half of the adult population worldwide. Oxidative stress is one of the pathophysiological mechanisms underlying periodontitis, which affects the occurrence and development of periodontitis. Exosomes are increasingly recognized as vehicles of intercellular communication and are closely related to periodontitis. However, the effects of oxidative stress on exosome secretion and the specific mechanisms remain elusive in human periodontal ligament cells (hPDLCs). The relationship between exosome secretion and the osteogenic differentiation of hPDLCs also needs to be investigated. METHODS: Isolated PDLSCs were identified using flow cytometry. Osteogenesis was measured using alizarin red staining and ALP staining. Expression of exosomal markers and PRMT1 was analyzed using western blot. Immunofluorescence was used to measure exosome uptake and the expression of EEA1. RESULTS: The secretion capacity of exosomes was markedly suppressed under oxidative stress. Protein arginine methyltransferase 1 (PRMT1) has been strongly associated with both oxidative stress and inflammation, and PRMT1 was significantly upregulated under oxidative stress conditions. Lentivirus-mediated overexpression of PRMT1 caused a significant reduction in the secretion of exosomes, but multivesicular bodies (MVBs) containing a large number of intraluminal vesicles (ILVs) were increased. Rab11a and Rab27a expression, which mediate MVBs fusion with cell membranes, decreased, although this phenomenon was restored after knocking down PRMT1 expression under oxidative stress. CONCLUSIONS: These results indicated that PRMT1 mediated a decrease in exosome secretion of hPDLCs. The decrease in Rab11a and Rab27a leads to a large accumulation of MVBs in cells and is one of the main reasons for impaired exosome secretion. The decrease in osteogenic differentiation of hPDLCs caused by H2 O2 may originate in part from the inhibition of exosome secretion.

C-reactive protein perturbs alveolar bone homeostasis: An experimental study of periodontitis and diabetes in the rat.

AIM: To explore the role of C-reactive protein (CRP) in periodontitis and diabetes and its mechanism in alveolar bone homeostasis. MATERIALS AND METHODS: In vivo, normal, and Crp knockout (KO) rats were randomly divided into control, diabetes, periodontitis, and diabetes and periodontitis groups, respectively. The diabetes model was established using a high-fat diet combined with streptozotocin injection. The periodontitis model was established by ligature combined with lipopolysaccharide (LPS) injection. Alveolar bones were analysed using micro-computed tomography, histology, and immunohistochemistry. In vitro, human periodontal ligament cells (hPDLCs) were treated with LPS and high glucose. CRP knockdown lentivirus or CRP overexpression adenovirus combined with a PI3K/AKT signalling inhibitor or agonist were used to explore the regulatory mechanism of CRP in osteogenesis and osteoclastogenesis of hPDLCs, as evidenced by alkaline phosphatase staining, Western blot, and quantitative polymerase chain reaction. RESULTS: In periodontitis and diabetes, CRP KO decreased the alveolar bone loss and the expression levels of osteoclastogenic markers, while increasing the expression levels of osteogenic markers. CRP constrained osteogenesis while promoting the osteoclastogenesis of hPDLCs via PI3K/AKT signalling under high glucose and pro-inflammatory conditions. CONCLUSIONS: CRP inhibits osteogenesis and promotes osteoclastogenesis via PI3K/AKT signalling under diabetic and pro-inflammatory conditions, thus perturbing alveolar bone homeostasis.

LIPUS inhibited the expression of inflammatory factors and promoted the osteogenic differentiation capacity of hPDLCs by inhibiting the NF-κB signaling pathway.

BACKGROUND AND OBJECTIVES: As a chronic infectious disease, periodontitis could lead to tooth and bone loss. Low-intensity pulsed ultrasound (LIPUS) is a safe, noninvasive treatment method to effectively inhibit inflammation and promote bone differentiation. However, the application of LIPUS in curing periodontitis is still rare. Our study aimed to explore the ability of LIPUS to inhibit inflammatory factors and promote the osteogenic differentiation capacity of human periodontal ligament cells (hPDLCs), and its underlying mechanism. MATERIAL AND METHODS: Human periodontal ligament cells were obtained and cultured from the premolar tissue samples for experiments. First, hPDLCs were treated for 24 hours using lipopolysaccharide (LPS) and then exposed to LIPUS (10 mW/cm2 , 30 mW/cm2 , 60 mW/cm2 , and 90 mW/cm2 ) to determine the appropriate intensity to inhibit expression of the inflammatory factors interleukin-6 (IL-6) and interleukin-8 (IL-8) expression. The expression of IL-6 and IL-8 was detected by real-time PCR and enzyme-linked immunosorbent assay. The safety of the most appropriate intensity of LIPUS was tested by a cell counting kit 8 test and an apoptosis assay. Then, LPS-induced hPDLCs were treated in osteogenic medium for 7-21 days with or without LIPUS (90 mW/cm2 , 30 min/d) stimulation. The osteogenic genes RUNX2, OPN, OSX, and OCN were measured by real-time PCR. Additionally, osteogenic differentiation capacity was determined using alkaline phosphatase (ALP) staining, ALP activity analysis, and Alizarin red staining. The activity of the nuclear factor-kappa B (NF-κB) signaling pathway was determined by western blotting, real-time PCR, immunofluorescence, and pathway blockade assays. RESULTS: Lipopolysaccharide significantly upregulated the production and gene expression of IL-6 and IL-8, while LIPUS stimulation significantly inhibited IL-6 and IL-8 expression in an intensity-dependent manner. LIPUS (90 mW/cm2 ) was chosen as the most appropriate intensity, and there was no detrimental influence on cell proliferation and status with or without osteogenic medium. In addition, consecutive stimulation with LIPUS (90 mW/cm2 ) for 30 min/d for 7 days could also inhibit IL-6 and IL-8 gene expression, upregulate the expression of the osteogenesis-related genes RUNX2, OPN, OSX, and OCN, and promote osteogenic differentiation capacity in osteogenic medium in inflamed hPDLCs. The NF-κB signaling pathway was inhibited with LIPUS (90 mW/cm2 ) via inhibition of the phosphorylation of IκBα and the translocation of p65 into the nucleus in inflamed hPDLCs. Additional investigations of the NF-κB inhibitor, BAY 11-7082, revealed that LIPUS (90 mW/cm2 ) acted similarly to BAY 11-7802 to inhibit the NF-κB signaling pathway and increase osteogenesis-related genes and promote the osteogenic differentiation capacity of inflamed hPDLCs. CONCLUSION: Low-intensity pulsed ultrasound (90 mW/cm2 ) stimulation could be a safe method to inhibit IL-6 and IL-8 in hPDLCs by inhibiting the NF-κB signaling pathway. The effect of LIPUS (90 mW/cm2 ) and BAY 11-7082 on LPS-induced inflammation demonstrated that both of these agents were capable of promoting osteogenesis-related gene expression and osteogenic differentiation in hPDLCs, suggesting that the effect of LIPUS on the promotion of osteogenic activity could be mediated in part through its ability to inhibit the NF-κB signal pathway. Hence, LIPUS could be a potential therapeutic method to cure periodontitis.

Effect of metformin on human periodontal ligament stem cells cultured with polydopamine-templated hydroxyapatite.

Polydopamine-templated hydroxyapatite (tHA) is a type of nano-biomaterial that can promote osteogenesis in bone tissue engineering. However, high concentrations of tHA stimulate production of reactive oxygen species (ROS), resulting in cell injury and apoptosis. Metformin has been demonstrated to activate the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, which induces autophagy and decreases ROS production to prevent apoptosis. The present study was performed to investigate the potential application of tHA in combination with metformin in periodontal bone tissue engineering. Human periodontal ligament stem cells (hPDLSCs) were exposed to tHA in the presence or absence of metformin, and cytocompatibility and osteogenesis were detected by related assays. Additionally, the autophagy signaling pathway was analyzed by western blotting. Polydopamine-templated hydroxyapatite, in combination with metformin, substantially reduced ROS production and apoptosis, and enhanced proliferation and osteogenic differentiation of hPDLSCs. Enhanced levels of microtubule-associated protein 1 light chain 3 II and Beclin-1 were observed after exposure to tHA plus metformin. Expression of phosphorylated AMPK was increased and that of phosphorylated mammalian target of rapamycin (mTOR) was decreased after exposure to tHA plus metformin. Taken together, our results demonstrate that tHA, combined with metformin, increases the viability of hPDLSCs via the AMPK/mTOR signaling pathway by regulating autophagy and further improving the osteogenic effect.

Temporal and spatial effects on C-reactive protein's regulation of inducible nitric oxide synthase production in periodontal disease.

BACKGROUND: Inducible nitric oxide synthase (iNOS) is associated with inflammation and osteoclastic differentiation in periodontal disease. This study was conducted to compare the time-dependent variation in iNOS production between the gingiva and other periodontal tissues and to explore the potential association with C-reactive protein (CRP) in early periodontal disease. METHODS: Ligature-induced periodontal disease models (0-14 days) were established in wild-type and CRP knockout rats. Changes in CRP, iNOS, and autophagy levels were examined in the gingiva and other periodontal tissues. Macrophages were treated with lipopolysaccharide and chloroquine to explore the role of autophagy in iNOS production. iNOS, CRP, and autophagy-related proteins were analyzed using Western blotting, immunostaining, and enzyme-linked immunosorbent assays. mRNA expression was detected by quantitative real-time polymerase chain reaction. Hematoxylin and eosin staining was used for histological analysis. Cathepsin K immunostaining and microcomputed tomography of the maxillae were performed to compare alveolar bone resorption. RESULTS: iNOS and CRP levels increased rapidly in periodontal tissues, as observed on Day 2 of ligature, then decreased more rapidly in the gingiva than in other periodontal tissues. CRP deficiency did not prevent iNOS generation, but effectively accelerated iNOS reduction and delayed alveolar bone loss. The CRP effect on iNOS was accompanied by a change in autophagy, which was reduced by CRP knockout. CONCLUSIONS: The regulation of iNOS by CRP shows temporospatial variation in early periodontal disease and is potentially associated with autophagy. These findings may contribute to the early detection and targeted treatment of periodontal disease.

Knockdown of SIRT3 perturbs protective effects of irisin against bone loss in diabetes and periodontitis.

A well-recognized risk factor for periodontitis, diabetes mellitus (DM) aggravates periodontal disease with increasing alveolar bone loss. As a novel myokine, irisin is closely linked with bone metabolism. Nonetheless, the effects of irisin on periodontitis under diabetic conditions and the underlying mechanisms remain poorly understood. Here, we showed that local irisin treatment ameliorates alveolar bone loss and oxidative stress, increases SIRT3 expression within periodontal tissues of our experimentally-induced diabetes and periodontitis (DP) rat models. By culturing the periodontal ligament cells (PDLCs) in vitro, we found that irisin could partially rescue inhibited cell viability, mitigate accumulated intracellular oxidative stress, ameliorate mitochondrial dysfunctions, and restore disturbed osteogenic and osteoclastogenic capacities of PDLCs when exposed to high glucose and pro-inflammatory stimulation. Furthermore, lentivirus-mediated SIRT3 knockdown was employed to unravel the underlying mechanism by which SIRT3 mediated irisin's beneficial effects on PDLCs. Meanwhile, in SIRT3-deficient mice, irisin treatment did not protect against alveolar bone destruction and oxidative stress accumulation in DP models, which underlined the crucial role of SIRT3 in mediating the positive effects of irisin on DP. Our findings, for the first time, revealed that irisin attenuates alveolar bone loss and oxidative stress via activation of the SIRT3 signaling cascade, and highlighted its therapeutic potential for the treatment of DP.

Low-intensity pulsed ultrasound regulates osteoblast-osteoclast crosstalk via EphrinB2/EphB4 signaling for orthodontic alveolar bone remodeling.

Background: The limited regenerative potential of periodontal tissue remains a challenge in orthodontic treatment, especially with respect to alveolar bone remodeling. The dynamic balance between the bone formation of osteoblasts and the bone resorption of osteoclasts controls bone homeostasis. The osteogenic effect of low-intensity pulsed ultrasound (LIPUS) is widely accepted, so LIPUS is expected to be a promising method for alveolar bone regeneration. Osteogenesis is regulated by the acoustic mechanical effect of LIPUS, while the cellular perception, transduction mode and response regulation mechanism of LIPUS stimuli are still unclear. This study aimed to explore the effects of LIPUS on osteogenesis by osteoblast-osteoclast crosstalk and the underlying regulation mechanism. Methods: The effects of LIPUS on orthodontic tooth movement (OTM) and alveolar bone remodeling were investigated via rat model by histomorphological analysis. Mouse bone marrow mesenchymal stem cells (BMSCs) and bone marrow monocytes (BMMs) were purified and used as BMSC-derived osteoblasts and BMM-derived osteoclasts, respectively. The osteoblast-osteoclast co-culture system was used to evaluate the effect of LIPUS on cell differentiation and intercellular crosstalk by Alkaline phosphatase (ALP), Alizarin Red S (ARS), tartrate-resistant acid phosphatase (TRAP) staining, real-time quantitative PCR, western blotting and immunofluorescence. Results: LIPUS was found to improve OTM and alveolar bone remodeling in vivo, promote differentiation and EphB4 expression in BMSC-derived osteoblasts in vitro, particularly when cells were directly co-cultured with BMM-derived osteoclasts. LIPUS enhanced EphrinB2/EphB4 interaction between osteoblasts and osteoclasts in alveolar bone, activated the EphB4 receptor on osteoblasts membrane, transduced LIPUS-related mechanical signals to the intracellular cytoskeleton, and gave rise to the nuclear translocation of YAP in Hippo signaling pathway, thus regulating cell migration and osteogenic differentiation. Conclusions: This study shows that LIPUS modulates bone homeostasis by osteoblast-osteoclast crosstalk via EphrinB2/EphB4 signaling, which benefits the balance between OTM and alveolar bone remodeling.

Clostridium butyricum MIYAIRI 588 alleviates periodontal bone loss in mice with diabetes mellitus.

The gut microbiota is a bridge linking periodontitis and systemic diseases, such as diabetes mellitus (DM). The probiotic Clostridium butyricum MIYAIRI 588 (CBM588) is reportedly an effective therapeutic approach for gut dysbiosis. Here, in a mouse model, we explored the therapeutic effect of CBM588 on periodontal bone destruction in DM and DM-associated periodontitis (DMP), as well as the underlying mechanism. Micro-computed tomography revealed that DM and DMP both aggravated periodontal bone destruction, which was alleviated by intragastric supplementation with CBM588. Moreover, 16S rRNA sequencing and untargeted metabolite analysis indicated that CBM588 ameliorated DMP-triggered dysbiosis and led to reduced oxidative stress associated with elevated 4-hydroxybenzenemethanol (4-HBA) in serum. Furthermore, in vitro and in vivo experiments found that the metabolite 4-HBA promoted nuclear factor erythroid 2-related factor 2 (Nrf2) signaling activation and modulated the polarization of macrophages, thus ameliorating inflammatory bone destruction in DMP. Our study demonstrates the protective effects of CBM588 in DM-induced mice, with and without ligature-induced periodontitis. The mechanism involves regulation of the gut microbiota and restoration of the integrity of the gut barrier to alleviate oxidative damage by elevating serum 4-HBA. This study suggests the possibility of CBM588 as a therapeutic adjuvant for periodontal treatment in diabetes patients.

Extracellular vesicles derived from human dental mesenchymal stem cells stimulated with low-intensity pulsed ultrasound alleviate inflammation-induced bone loss in a mouse model of periodontitis.

Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have emerged as a new mode of intercellular crosstalk and are responsible for many of the therapeutic effects of MSCs. To promote the application of MSC-EVs, recent studies have focused on the manipulation of MSCs to improve the production of EVs and EV-mediated activities. The current paper details an optimization method using non-invasive low-intensity pulsed ultrasound (LIPUS) as the stimulation for improving oral MSC-EV production and effectiveness. Stem cells from apical papilla (SCAP), a type of oral mesenchymal stem cell, displayed intensity-dependent pro-osteogenic and anti-inflammatory responses to LIPUS without significant cytotoxicity or apoptosis. The stimuli increased the secretion of EVs by promoting the expression of neutral sphingomyelinases in SCAP. In addition, EVs from LIPUS-induced SCAP exhibited stronger efficacy in promoting the osteogenic differentiation and anti-inflammation of periodontal ligament cells in vitro and alleviating oral inflammatory bone loss in vivo. In addition, LIPUS stimulation affected the physical characteristics and miRNA cargo of SCAP-EVs. Further investigations indicated that miR-935 is an important mediator of the pro-osteogenic and anti-inflammatory capabilities of LIPUS-induced SCAP-EVs. Taken together, these findings demonstrate that LIPUS is a simple and effective physical method to optimize SCAP-EV production and efficacy.

Systemic antibiotics increase microbiota pathogenicity and oral bone loss.

Periodontitis is the most widespread oral disease and is closely related to the oral microbiota. The oral microbiota is adversely affected by some pharmacologic treatments. Systemic antibiotics are widely used for infectious diseases but can lead to gut dysbiosis, causing negative effects on the human body. Whether systemic antibiotic-induced gut dysbiosis can affect the oral microbiota or even periodontitis has not yet been addressed. In this research, mice were exposed to drinking water containing a cocktail of four antibiotics to explore how systemic antibiotics affect microbiota pathogenicity and oral bone loss. The results demonstrated, for the first time, that gut dysbiosis caused by long-term use of antibiotics can disturb the oral microbiota and aggravate periodontitis. Moreover, the expression of cytokines related to Th17 was increased while transcription factors and cytokines related to Treg were decreased in the periodontal tissue. Fecal microbiota transplantation with normal mice feces restored the gut microbiota and barrier, decreased the pathogenicity of the oral microbiota, reversed the Th17/Treg imbalance in periodontal tissue, and alleviated alveolar bone loss. This study highlights the potential adverse effects of long-term systemic antibiotics-induced gut dysbiosis on the oral microbiota and periodontitis. A Th17/Treg imbalance might be related to this relationship. Importantly, these results reveal that the periodontal condition of patients should be assessed regularly when using systemic antibiotics in clinical practice.

Portable Handheld "SkinPen" Loaded with Biomaterial Ink for In Situ Wound Healing.

In situ bioprinting has emerged as an attractive tool for directly depositing therapy ink at the defective area to adapt to the irregular wound shape. However, traditional bioprinting exhibits an obvious limitation in terms of an unsatisfactory bioadhesive effect. Here, a portable handheld bioprinter loaded with biomaterial ink is designed and named "SkinPen". Gelatin methacrylate (GelMA) and Cu-containing bioactive glass nanoparticles (Cu-BGn) serve as the main components to form the hydrogel ink, which displays excellent biocompatibility and antibacterial and angiogenic properties. More importantly, by introducing ultrasound and ultraviolet in a sequential programmed manner, the SkinPen achieves in situ instant gelation and amplified (more than threefold) bioadhesive shear strength. It is suggested that ultrasound-induced cavitation and the resulting topological entanglement contribute to the enhanced bioadhesive performance together. Combining the ultrasound-enhanced bioadhesion with the curative role of the hydrogel, the SkinPen shows a satisfactory wound-healing effect in diabetic rats. Given the detachable property of the SkinPen, the whole device can be put in a first-aid kit. Therefore, the application scenarios can be expanded to many kinds of accidents. Overall, this work presents a portable handheld SkinPen that might provide a facile but effective approach for clinical wound management.

Pyroptosis in periodontitis: From the intricate interaction with apoptosis, NETosis, and necroptosis to the therapeutic prospects.

Periodontitis is highly prevalent worldwide. It is characterized by periodontal attachment and alveolar bone destruction, which not only leads to tooth loss but also results in the exacerbation of systematic diseases. As such, periodontitis has a significant negative impact on the daily lives of patients. Detailed exploration of the molecular mechanisms underlying the physiopathology of periodontitis may contribute to the development of new therapeutic strategies for periodontitis and the associated systematic diseases. Pyroptosis, as one of the inflammatory programmed cell death pathways, is implicated in the pathogenesis of periodontitis. Progress in the field of pyroptosis has greatly enhanced our understanding of its role in inflammatory diseases. This review first summarizes the mechanisms underlying the activation of pyroptosis in periodontitis and the pathological role of pyroptosis in the progression of periodontitis. Then, the crosstalk between pyroptosis with apoptosis, necroptosis, and NETosis in periodontitis is discussed. Moreover, pyroptosis, as a novel link that connects periodontitis with systemic disease, is also reviewed. Finally, the current challenges associated with pyroptosis as a potential therapeutic target for periodontitis are highlighted.

Bibliometrics and visualization analysis regarding research on the development of microplastics.

Microplastics have caused considerable harm to the environment and threatened human health due to their strong adsorption and hard biodegradation. Therefore, the research of microplastic received increasing attention recently, producing numbers of related achievements. To comprehensively grasp the quantitative information of published papers on "microplastics," we analyzed the research progress and hotspots of "microplastics" through visualization software "VOSviewer." The results show that the number of literature on microplastics published from 2009 to 2019 increased exponentially (R2 = 0.9873). The top 10 cited references are mainly in "zooplankton ingesting microplastics," "microplastics in artificially cultivated bivalve," "microplastics in surface waters such as lakes," etc. The cutting-edge microplastics research is adsorption, biodegradation, ingestion and accumulation model, and toxicity analysis. In addition, the results predict that the combination of constructed wetland, biotechnology, and photocatalysis to remove microplastics will become new hotspots. The study provides researchers in microplastics with an overview of existing research and directional guidance for future research.

Proteomics and N-glycoproteomics analysis of an extracellular matrix-based scaffold-human treated dentin matrix.

Extracellular matrix (ECM)-based biomaterials developed from mammalian tissues have been successfully used in preclinical and clinical tissue engineering applications. We have previously reported about the applicability of dentin-based scaffold, treated dentin matrix (TDM), for tooth root regeneration. However, TDM protein composition has not been characterized. Here, we used a shotgun proteomic strategy to profile human TDM proteome. N-glycoproteins were enriched by lectin affinity chromatography and identified by mass spectrometry. The total human TDM proteome was compared with the previously published human dentin proteome, and bioinformatics analysis were performed accordingly. In total, 708 proteins were identified by mass spectrometry in human TDM, of which 208 were N-glycoproteins with 318 identified glycosylation sites. Collagens, proteoglycans, small integrin-binding ligand N-linked glycoproteins (SIBLINGs), and growth factors, such as COL1A1, biglycan, dentin sialoprotein, and transforming growth factor beta 1, were identified. Glycoproteins were enriched in "biological processes" Gene Ontology terms such as cellular process, biological regulation, response to stimulus, metabolic process, immune system process, and biological adhesion. Thus, our comprehensive study of the human TDM proteome revealed that dentin proteins are more heterogeneous than previously documented. Our findings provide clues for designing new biomaterials for tooth root regeneration and understanding dentin formation.

Smart surface coating of drug nanoparticles with cross-linkable polyethylene glycol for bio-responsive and highly efficient drug delivery.

Many drug molecules can be directly used as nanomedicine without the requirement of any inorganic or organic carriers such as silica and liposome nanostructures. This new type of carrier-free drug nanoparticles (NPs) has great potential in clinical treatment because of its ultra-high drug loading capacity and biodegradability. For practical applications, it is essential for such nanomedicine to possess robust stability and minimal premature release of therapeutic molecules during circulation in the blood stream. To meet this requirement, herein, we develop GSH-responsive and crosslinkable amphiphilic polyethylene glycol (PEG) molecules to modify carrier-free drug NPs. These PEG molecules can be cross-linked on the surface of the NPs to endow them with greater stability and the cross-link is sensitive to intracellular environment for bio-responsive drug release. With this elegant design, our experimental results show that the liberation of DOX from DOX-cross-linked PEG NPs is dramatically slower than that from DOX-non-cross-linked PEG NPs, and the DOX release profile can be controlled by tuning the concentration of the reducing agent to break the cross-link between PEG molecules. More importantly, in vivo studies reveal that the DOX-cross-linked PEG NPs exhibit favorable blood circulation half-life (>4 h) and intense accumulation in tumor areas, enabling effective anti-cancer therapy. We expect this work will provide a powerful strategy for stabilizing carrier-free nanomedicines and pave the way to their successful clinical applications in the future.

The aspect ratio effect of drug nanocrystals on cellular internalization efficiency, uptake mechanisms, and in vitro and in vivo anticancer efficiencies.

In this paper, we investigated the aspect ratio (AR) effect of anticancer drug nanocrystals (NCs) on their cellular internalization efficiency, uptake mechanisms, biodistributions as well as in vitro and in vivo antitumor efficiencies. Both confocal imaging and flow cytometry show that shorter NCs with AR = 1.3 have a much faster cellular uptake rate and a much higher anticancer efficacy than longer NCs. All NCs with different ARs were found to enter the cells via an energy-dependent clathrin-mediated pathway. In vivo experiments indicate that NCs with higher ARs have a shorter half-life and are more easily captured by the liver, while the corresponding tumor uptake decreased. We also observed that NCs with the smallest AR have the highest therapeutic efficacy with appreciably less weight loss. These results would assist in the future design of drug NCs and may lead to the development of new drug nanostructures for biomedical applications.

Smart nanorods for highly effective cancer theranostic applications.

Combination of chemotherapy and photothermal therapy is considered to be a promising strategy for the next generation of cancer treatments. However, it has been limited by difficulties in obtaining high drug payload chemo-photothermal agents, and thus complete destruction of tumor without recurrence has never been achieved, unless they are conjugated with some targeting ligands for special targeted drug delivery. Herein, iron oxide nanoparticle (IONP)-doped 10-hydroxycamptothecin drug nanorods (HCPT NRs), with an organic conducting polymer poly(4-styrenesulfonate) (PEDOT) coating outside, are developed for cancer diagnosis and chemo-photothermal therapy. The drug-loading capacity of HCPT in the complex NRs reaches up to 72%, which is much higher than previously reported carrier-based nanocomposites. In vitro studies show that the resulting NRs demonstrate an excellent chemo-photothermal synergistic effect for tumor ablation. More importantly, 100% in vivo tumor elimination is achieved under a low laser power density of 1 W cm(-) (2) without weight loss and tumor recurrence. Moreover, IONP endow these drug nanocomposites with imaging capabilities, thus rendering the resulting HCPT-PEDOT NR an all-in-one processing system for diagnosis and treatment with low systematic toxicity.

Ultrabright and ultrastable near-infrared dye nanoparticles for in vitro and in vivo bioimaging.

We report a new strategy of using carrier-free pure near-infrared (NIR) dye nanoparticles (NPs) to achieve highly luminescent NIR fluorescent probes for in vitro and in vivo imaging. Bis(4-(N-(2-naphthyl)phenylamino) phenyl)-fumaronitrile (NPAPF) NPs are shown to exhibit favorable biocompatibility, wide-range pH stability (pH 4-10) and much more superior photostability than conventional dyes. Importantly, the combined merits of high dye loading content and aggregation-induced emission enhancement properties, endow the NIR probes with high brightness and a high quantum yield up to 14.9%. The NPAPF NPs can be readily conjugated with folic acid for targeted in vitro cell imaging. Applications of the NPs probes in high efficiency in vivo and ex vivo imaging were successfully demonstrated. Intense fluorescent signals of NPAPF NPs can be distinctly, selectively and spatially resolved in tumor sites with ultrahigh sensitivity, even with 5 ms exposure time, due to the preferentially accumulation of NPs in tumor sites through passive enhanced permeability and retention effect. The totality of results clearly demonstrate the exciting potential of the functionalized NPAPF NPs as a NIR fluorescent probe for in vitro and in vivo imaging and diagnostics.