Accumulation of extracellular elastin-derived peptides disturbed neuronal morphology and neuron-microglia crosstalk in aged brain.

Extracellular elastin-derived peptides (EDPs) accumulate in the aging brain and have been associated with vascular dementia and Alzheimer's disease (AD). The activation of inflammatory processes in glial cells with EDP treatment has received attention, but not in neurons. To properly understand EDPs' pathogenic significance, the impact on neuronal function and neuron-microglia crosstalk was explored further. Among the EDP molecules, Val-Gly-Val-Ala-Pro-Gly (VGVAPG) is a typical repeating hexapeptide. Here, we observed that EDPs-VGVAPG influenced neuronal survival and morphology in a dose-dependent manner. High concentrations of VGVAPG induced synapse loss and microglia hyperactivation in vivo and in vitro. Following EDP incubation, galectin 3 (Gal-3) released by neurons served as a chemokine, attracting microglial engulfment. Blocking Gal-3 and EDP binding remedied synapse loss in neurons and phagocytosis in microglia. In response to the accumulation of EDPs, proteomics in matrix remodeling and cytoskeleton dynamics, such as a disintegrin and metalloproteinase (ADAM) family, were engaged. These findings in extracellular EDPs provided more evidence for the relationship between aging and neuron dysfunction, increasing the insight of neuroinflammatory responses and the development of new specialized extracellular matrix remolding-targeted therapy options for dementia or other neurodegenerative disease.

Renal Clearable Nanodots-Engineered Erythrocytes with Enhanced Circulation and Tumor Accumulation for Photothermal Therapy of Hepatocellular Carcinoma.

Living cell-mediated nanodelivery system is considered a promising candidate for targeted antitumor therapy; however, their use is restricted by the adverse interactions between carrier cells and nanocargos. Herein, a novel erythrocyte-based nanodelivery system is developed by assembling renal-clearable copper sulfide (CuS) nanodots on the outer membranes of erythrocytes via a lipid fusion approach, and demonstrate that it is an efficient photothermal platform against hepatocellular carcinoma. After intravenous injection of the nanodelivery system, CuS nanodots assembled on erythrocytes can be released from the system, accumulate in tumors in response to the high shear stress of bloodstream, and show excellent photothermal antitumor effect under the near infrared laser irradiation. Therefore, the erythrocyte-mediated nanodelivery system holds many advantages including prolonged blood circulation duration and enhanced tumor accumulation. Significantly, the elimination half-life of the nanodelivery system is 74.75 ± 8.77 h, which is much longer than that of nanodots (33.56 ± 2.36 h). Moreover, the other two kinds of nanodots can be well assembled onto erythrocytes to produce other erythrocyte-based hitchhiking platforms. Together, the findings promote not only the development of novel erythrocyte-based nanodelivery systems as potential platforms for tumor treatment but also their further clinical translation toward personalized healthcare.

The role of retinoic acid receptor-related orphan receptors in skeletal diseases.

Bone homeostasis, depending on the balance between bone formation and bone resorption, is responsible for maintaining the proper structure and function of the skeletal system. As an important group of transcription factors, retinoic acid receptor-related orphan receptors (RORs) have been reported to play important roles in bone homeostasis by regulating the transcription of target genes in skeletal cells. On the other hand, the dysregulation of RORs often leads to various skeletal diseases such as osteoporosis, rheumatoid arthritis (RA), and osteoarthritis (OA). Herein, we summarized the roles and mechanisms of RORs in skeletal diseases, aiming to provide evidence for potential therapeutic strategies.

Effect of recombinant human fibroblast growth factor 21 on the mineralization of cementoblasts and its related mechanism.

OBJECTIVES: To investigate the effect of recombinant human fibroblast growth factor 21 (rhFGF21) on the proliferation and mineralization of cementoblasts and its mechanism. METHODS: Hematoxylin eosin, immunohistochemical staining, and immunofluorescence were used to detect the expression and distribution of fibroblast growth factor 21 (FGF21) in rat periodontal tissues and cementoblasts (OCCM-30), separately. Cell Counting Kit-8 was used to detect the proliferation of OCCM-30 under treatment with rhFGF21. Alkaline phosphatase staining and Alizarin Red staining were used to detect the mineralization state of OCCM-30 after 3 and 7 days of mineralization induction. The transcription and protein expression of the osteogenic-related genes Runx2 and Osterix were detected by real-time quantitative polymerase chain reaction (PCR) and Western blot analysis. The expression levels of genes of transforming growth factor ß (TGFß)/bone morphogenetic protein (BMP) signaling pathway in OCCM-30 were detected through PCR array analysis. RESULTS: FGF21 was expressed in rat periodontal tissues and OCCM-30. Although rhFGF21 had no significant effect on the proliferation of OCCM-30, treatment with 50 ng/mL rhFGF21 could promote the mineralization of OCCM-30 cells after 7 days of mineralization induction. The transcriptional levels of Runx2 and Osterix increased significantly at 3 days of mineralization induction and decreased at 5 days of mineralization induction. Western blot analysis showed that the protein expression levels of Runx2 and Osterix increased during mineralization induction. rhFGF21 up-regulated Bmpr1b protein expression in cells. CONCLUSIONS: rhFGF21 can promote the mineralization ability of OCCM-30. This effect is related to the activation of the TGFß/BMP signaling pathway.

Recent advances of antioxidant low-dimensional carbon materials for biomedical applications.

As the primary cause of many tissue damage and diseases, reactive oxygen species (ROS) and reactive nitrogen species (RNS) are well known to be extremely harmful to a variety of biological components in cells including lipids, proteins and DNA. Numerous antioxidative nanomaterials have been artificially designed and rationally synthesized to protect cells from the oxidative damage caused by reactive oxygen species/reactive nitrogen species. Recent studies demonstrate that low dimensional carbon antioxidative nanomaterials have received a lot of attention owing to their tiny nanoscales and unique physicochemical property. As a result, a brief overview of recent advancements in antioxidant low-dimensional carbon materials is provided. Typically, carbon nanomaterials are classified according to their nanostructure dimensions, which are zero-dimension, one-dimension, and two-dimension. Last but not least, the challenges and perspectives of these high-performance low-dimensional materials in biomedical fields and further clinical usages are discussed as well.

Zeolites: A series of promising biomaterials in bone tissue engineering.

As an important worldwide medical issue, bone defect exhibits a variety of physical and psychological consequences on sufferers. Some features of clinical treatments including bone grafting and limb shortening are not satisfactory. Recently, bone tissue engineering has been considered as the most effective approach to dealing with the issue of bone deformities. Meanwhile, a variety of biomaterials have been rationally designed and created for the bone regeneration and tissue repairing. Among all these admirable biomaterials for bone remodeling, zeolite-based materials can serve as efficient scaffold candidates with excellent osteo-inductivity. In addition, the porous nature and high biocompatibility of zeolites endow them with the ability as ideal substrates for cell adhesion and proliferation. More importantly, zeolites are investigated as potential coating materials for implants because they have been proven to increase osteo-conductivity and aid in local elastic modeling. Last but not least, zeolites can also be used to treat bone disorders and act as dietary supplements during the practical applications. Accordingly, numerous benefits of zeolite prompt us to summarize their recent biomedical progress including but not limited to the distinguishing characteristics, broad classifications, as well as promising usages in bone tissue engineering.

A sustained-release Trametinib bio-multifunction hydrogel inhibits orthodontically induced inflammatory root resorption.

Orthodontic tooth movement (OTM) is a bone reconstruction process. In most cases, OTM could induce root resorption as a common side effect, called orthodontically induced inflammatory root resorption (OIIRR). OIIRR affects tooth health and interferes with the stability of orthodontic treatment. Osteoclasts, which perform bone resorption in OTM, attack cementum, causing OIIRR. Many signaling pathways are involved in the maturation and differentiation of osteoclasts, among which the ERK1/2 is one of the important pathways. In this experiment, we added Trametinib (Tra), a specific inhibitor of ERK1/2, to catechol-modified chitosan (CHI-C) and oxidized dextran (ODex) to form a CCOD-Trametinib composite hydrogel (CCOD-Tra) to prevent OIIRR. CCOD-Tra exhibited good biocompatibility, injectability, strong adhesion, good hemostatic function and sustained release of Tra. We performed local injection of CCOD-Tra into the periodontal tissues of rats. CCOD-Tra firmly adhered to the periodontal tissues and then released Tra to establish a good biological environment and maintain a drug concentration at a high level around the roots for a long time. H&E, TRAP, immunochemistry staining and micro-CT indicated that CCOD-Tra had a good effect in terms of preventing OIIRR. Cell experiments showed that CCOD-Tra reduced the expression of TRAP, MMP-9 and C-FOS in osteoclast cells through the ERK1/2 signaling pathway to inhibit the differentiation and maturation of osteoclasts. Based on the above results, we concluded that CCOD-Tra had the ability to prevent OIIRR, the high adhesion and injectability of CCOD may provide better therapeutic ideas for clinical prevention of OIIRR.

Protein-Inorganic Hybrid Nanoflowers as Efficient Biomimetic Antibiotics in the Treatment of Bacterial Infection.

Nanozymes have been developed as new generation of biomimetic antibiotics against wound infection. However, most of new-developed nanozymes based on inorganic particles or hybrid ones usually originate from incompatible raw materials or unwanted metal salts, highly limiting their further biomedical usages. To overcome above drawbacks, it is highly required to develop novel nanozymes with great antibacterial activity by using biocompatible reagents and endogenous metal species as raw materials. Here, we demonstrated that bovine serum albumin enwrapped copper phosphate-based protein-inorganic hybrid nanoflowers possessed intrinsic peroxidase-like activity, which could be used as efficient biomimetic antibiotics against bacterial infection via the nanozyme-mediated generation of high toxic reactive oxygen species (ROS). With the admirable peroxidase-like activity, our nanoflowers could efficiently kill drug-resistance bacteria under physiological conditions, improve the wound healing after pathogen-induced infection, as well as avoid the potential tissue injury in time. Comprehensive toxicity exploration of these nanoflowers indicated their high biocompatibility and excellent biosafety. Our current strategy toward the design of protein-inorganic hybrid nanozymes with high biosafety and few side effects could provide a new paradigm for the development of nanozyme-based antibacterial platform in future.

IL1ß inhibits differentiation of cementoblasts via microRNA-325-3p.

Cementum regeneration is considered the gold standard for the treatment of periodontitis. As one of the most important primary proinflammatory cytokines, interleukin 1ß (IL1ß) plays an essential role during the early stage of periodontitis and its amounts simultaneously increase dramatically during this stage. Though promising, the differentiation of cementoblasts upon IL1ß-induced inflammation of the microenvironment and the relative interaction mechanism are still unknown. Here, we found that IL1ß inhibited cementoblast differentiation and microRNA-325-3p (miR-325-3p) was increased during IL1ß-stimulated cementoblasts. Bioinformatics analysis and luciferase reporter assay demonstrated miR-325-3p targeted runt-related transcription factor 2 directly. Transfection of miR-325-3p suppressed cementoblast differentiation in vitro and the formation of cementum-like tissues in vivo. The inhibitor of miR-325-3p could mitigate the above effects induced by IL1ß. Accordingly, our finding suggests a critical role of miR-325-3p in linking inflammation to impaired cementum regeneration and provides a potential possibility for applying miR-325-3p inhibitors in the treatment of periodontitis-related bone loss.

MicroRNA-378-3p/5p represses proliferation and induces apoptosis of oral squamous carcinoma cells via targeting KLK4.

Oral squamous cell carcinoma (OSCC) is one of the most common types of head and neck neoplasm. Down-regulation of hsa-microRNA-378 (miR-378) has been proved in OSCC tissues, suggesting that miR-378 might play crucial roles in the progression of OSCC. The present study aimed to evaluate the effect of miR-378-3p/5p on the proliferation and apoptosis of OSCC in vitro and in vivo. According to the results, lentivirus-mediated overexpression of miR-378 lowered the colony formation efficiency, blocked cell cycle progression, and decreased the percentage of Ki-67 positive cells, whereas knockdown of miR-378-3p/5p led to the opposite results. Furthermore, the apoptosis of OSCC cells was induced by the overexpression of miR-378 as evidenced by decreasing Bcl-2/Bax ratio, increasing cleaved caspase-9, cleaved caspase-3, and cleaved PARP levels, and promoting the release of cytochrome c into the cytoplasm. However, the above results were reversed by miR-378-3p/5p silencing. In addition, the overexpression of miR-378 inhibited the activation of PI3K/AKT signalling pathway. Conversely, miR-378-3p/5p knockdown resulted in the inactivation of PI3K/AKT signalling pathway. Mechanically, we validated that miR-378-3p/5p could target kallikrein-related peptidase 4 (KLK4), and enforced overexpression of KLK4 counteracted miR-378 overexpression-induced apoptosis. Finally, tumourigenesis in nude mice was suppressed by the overexpression of miR-378, which was promoted by miR-378-3p/5p silencing. Taken together, these results suggest that miR-378 may be a potential target in the diagnoses and treatment of OSCC.

Xingfu Bao et al. The Effect on Proliferation and Differentiation of Cementoblast by Using Sclerostin as Inhibitor. Int. J. Mol. Sci. 2013, 14, 21140.

The authors wish to make the following correction to this paper [...].

Sema6A-plexin-A2 axis stimulates RANKL-induced osteoclastogenesis through PLCγ-mediated NFATc1 activation.

Recently, several plexins and semaphorins have been associated with osteoclastogenesis, a vital process for bone remodeling. Plexin-A2 is implicated in bone homeostasis, however, whether it plays a role in osteoclastogenesis and the underlying mechanism remain unknown. We show that plexin-A2 expression is upregulated during RANKL-induced osteoclastogenesis. In addition, the soluble Sema6A fused with IgG1 Fc region (Fc-Sema6A) interacts with plexin-A2 from cell lysates of osteoclasts, suggesting that plexin-A2 acts as a receptor of Sema6A in osteoclasts. Moreover, Sema6A treatment stimulates RANKL-induced osteoclastogenesis, and this effect is abolished when plexin-A2 is neutralized, which illustrates an indispensable role of plexin-A2 in mediating Sema6A effect on osteoclastogenesis. Mechanistically, Sema6A-plexin-A2 axis enhances RANKL-induced activation of PLCγ as well as downstream target NFATc1, one master transcriptional factor of osteoclastogenesis. Lastly, inhibition of PLCγ by pharmacological inhibitor U73122 abrogates Sema6A-stimulated NFATc1 activation and RANKL-induced osteoclastogenesis, thus demonstrating that the PLCγ-mediated NFATc1 activation accounts for the promotive role of Sema6A-plexin-A2 axis in RANKL-induced osteoclastogenesis. Taken together, this study uncovers a novel role of Sema6A and plexin-A2 in osteoclastogenesis, and also offers them as possible therapeutic targets in the intervention of osteolytic diseases.

Polydopamine Nanoparticles as Efficient Scavengers for Reactive Oxygen Species in Periodontal Disease.

Antioxidative therapy has been considered an efficient strategy for the treatment of a series of excessive reactive oxygen species (ROS)-triggered diseases, including oxidative-stress-induced periodontal disease. However, current natural enzymes and nanozymes often show their high specificity toward given ROS and have insufficient antioxidative effects against multiple ROS generated in the diseases process. Meanwhile, multienzyme-based antioxidant defense systems are usually confined by the complicated synthesis as well as potential unwanted residue and toxicity. Various supports are highly needed to immobilize natural enzymes and antioxidants during the biorelated usages due to their low operational stability and difficulty of reuse. To overcome these limitations, we develop a high-performance platform by using biodegradable polydopamine nanoparticles (PDA NPs) as smart ROS scavengers in oxidative stress-induced periodontal disease. Although PDA-based materials are well-known to eliminate ROS both in vitro and in vivo, their antioxidative performance in periodontal disease and relative mechanisms have yet to be well-explored. In this study, PDA NPs can act as ROS scavengers in dental specialties with ideal outcomes. Spectroscopic and in vitro experiments provide strong evidence for the roles of PDA NPs in scavenging multiple ROS and suppressing ROS-induced inflammation reactions. In addition to the above investigations, the results from a murine periodontitis model clearly demonstrate the feasibility of PDA NPs as robust antioxidants with which to remove ROS and decrease periodontal inflammation without any side effects. Taken together, the results from our present study will provide valuable insight into the development of safe and efficient antioxidant defense platforms for further biomedical uses.

An Enzyme Cascade-Triggered Fluorogenic and Chromogenic Reaction Applied in Enzyme Activity Assay and Immunoassay.

An enzyme cascade-triggered reaction with novel signal generation mechanism is beneficial for the development and insight of the enzyme cascade, which is extensively used for signal transduction in potential applications. Inspired by the fluorogenic and chromogenic reaction between dopamine and resorcinol, and the specific catalytic properties of alkaline phosphatase (ALP) and tyrosinase, we designed and synthesized an unconventional substrate of ALP, named p-aminoethyl-phenyl phosphate disodium salt (PAPP). As expected, the ALP and tyrosinase-incubated PAPP solution exhibited pale yellow with intense blue fluorescence upon addition of resorcinol, owing to the ALP-catalyzed transformation of PAPP into an intermediate tyramine, and the tyrosinase-catalyzed hydroxylation of tyramine to dopamine, as well as the specific reaction between dopamine and resorcinol. Therefore, an enzyme cascade system has been developed herein based on the ALP and tyrosinase coupled enzymes-triggered fluorogenic and chromogenic reaction. According to the direct relationship between the activity of ALP/tyrosinase and absorbance/fluorescence intensity of the resultant solution, the proposed enzyme cascade-triggered reaction was utilized for assaying ALP and tyrosinase activity with fluorometric and colorimetric dual-readout signals. Furthermore, such enzyme cascade catalysis process was integrated into the ALP-based cascade enzyme-linked immunosorbent assay with dual-readout signals, resulting in the sensitive detection of cardiac troponin I in diluted serum.

Alkaline Phosphatase Assay Based on the Chromogenic Interaction of Diethanolamine with 4-Aminophenol.

Diethanolamine (DEA) has been extensively utilized as an alkaline buffer in current assays of alkaline phosphatase (ALP) activity in the past decades. While playing the role of a buffer, the chemical reactivity of DEA has been widely ignored in such assays. Herein, we report an interesting chromogenic interaction between DEA and 4-aminophenol (AP) in the presence of H2O for the first time, which inspires us to develop a novel DEA-participated ALP activity assay by using 4-aminophenyl phosphate (APP) as a substrate. This APP/DEA-based colorimetric approach has been proved to be comparable and even superior to the conventional p-nitrophenyl phosphate (pNPP)-based one, especially in the low ALP activity region, due to its higher sensitivity. The clear response mechanism and excellent sensing performance ensure that it can be further applied to determining ALP activity in real biological samples, screening potential ALP inhibitors in vitro, establishing ALP-enabled ELISA, and even fluorophore-assisted fluorescent ALP activity assay. It is demonstrated that this strategy not only possesses a good feasibility, but also exhibits a promising outlook for a series of ALP-related and -extended detections.

In Situ Fluorogenic and Chromogenic Reactions for the Sensitive Dual-Readout Assay of Tyrosinase Activity.

As a well-known copper-containing oxidase, tyrosinase has been anticipated to serve as the biomarker of skin diseases. We describe here an exquisite label-free fluorescent and colorimetric dual-readout assay of its activity, inspired by the specific oxidation ability of monophenolamine substrates to catecholamines and a unique fluorogenic reaction between resorcinol and catecholamines. By employing commercially available tyramine as the model substrate (dopamine as the product), it is found that the tyrosinase-incubated tyramine solution exhibits obvious pale yellow with intense blue fluorescence in the presence of resorcinol and O2, where the absorbance and fluorescence intensity are directly related to the concentration of added tyrosinase (i.e., the amount of conversion of tyramine to dopamine). The overall process of sensing tyrosinase activity takes less than 100 min at ambient temperature and pressure conditions with exceedingly simple operation procedure, explicit response mechanism, and formation of fluorophore with high quantum yield from scratch. Furthermore, such a convenient, rapid, cost-effective, and highly sensitive dual-readout assay exhibits promising prospect for the tyrosinase activity in extensive bioassays and clinic research as well as in screening potential tyrosinase inhibitors.

Strontium promotes cementoblasts differentiation through inhibiting sclerostin expression in vitro.

Cementogenesis, performed by cementoblasts, is important for the repair of root resorption caused by orthodontic treatment. Based on recent studies, strontium has been applied for osteoporosis treatment due to its positive effect on osteoblasts. Although promising, the effect of strontium on cementoblasts is still unclear. So the aim of this research was to clarify and investigate the effect of strontium on cementogenesis via employing cementoblasts as model. A series of experiments including MTT, alkaline phosphatase activity, gene analysis, alizarin red staining, and western blot were carried out to evaluate the proliferation and differentiation of cementoblasts. In addition, expression of sclerostin was checked to analyze the possible mechanism. Our results show that strontium inhibits the proliferation of cementoblasts with a dose dependent manner; however, it can promote the differentiation of cementoblasts via downregulating sclerostin expression. Taking together, strontium may facilitate cementogenesis and benefit the treatment of root resorption at a low dose.

Effect of silica-based nanomaterials and their derivate with PEGylation on cementoblasts.

The applications of silica-based nanomaterials in dental fields as multifunctional scaffolds and carriers have been widely documented in recent years. However, toxicity of this type of nanoparticles in dental cells has not been elucidated in detail. The aim of present study was to investigate the effects of naked and PEGylated silica nanoparticles on cementoblasts. Methods including MTT assay, apoptosis, LDH, as well as ROS analysis were introduced in our study. Moreover, ALP analysis and alizarin red staining were additionally performed to indicate the influence of SiO2 and PEG-SiO2 on cementoblast differentiation. Results obtained from our designs and experiments demonstrated that naked silica nanoparticles could induce more cell toxicity than PEG-SiO2 nanoparticles, indicating PEGylation could efficiently reduce in vitro toxicity from several sections including ROS, LDH, and other important routes. Based on above results, we concluded that it was so necessary to process PEGylation while silica-based materials were applied in biomedicine and related fields including dental area.

Lithium chloride attenuates root resorption during orthodontic tooth movement in rats.

Root resorption is a common side effect of orthodontic treatment. In the current study, lithium chloride (LiCl), a Wnt signaling activator, was examined to determine its effect on root resorption. In total, 10 Sprague Dawley rats were randomly allocated into the experimental group (EG) and control group (CG). Each group consisted of five subjects. By using closed nickel-titanium coil springs, a 50-g force was applied between the upper incisors and the maxillary right first molars in order to mimic orthodontic biomechanics in the EG and CG for 14 days. During the 14 days, the EG rats were gavage-fed 200 mg/kg LiCl every 48 h. Next, digital radiographs were captured using a micro-computational tomography scanner. The movement of the maxillary first molars and the root resorption area ratio were measured electronically on the digital radiographs. The outcomes were analyzed using ANOVA. Following 14 days of experimental force application, all rats had spaces of varying sizes between the first and second right maxillary molars. The average distance measured in the CG was slightly higher than in the EG, however, the difference was not found to be statistically significant (P=0.224). Root resorption craters were observed in the groups following the experiment. Rough cementum areas were observed on the mesial surface of the distobuccal and distopalatal roots. The mean root resorption area ratio of CG was significantly greater than EG (P<0.05). Results of the present study indicate that LiCl can attenuate orthodontically induce root resorption during orthodontic tooth movement. The effect of LiCl on tooth movement is insignificant.