Mechanically induced M2 macrophages are involved in bone remodeling of the midpalatal suture during palatal expansion.

BACKGROUND: Palatal expansion is a common way of treating maxillary transverse deficiency. Under mechanical force, the midpalatal suture is expanded, causing local immune responses. This study aimed to determine whether macrophages participate in bone remodeling of the midpalatal suture during palatal expansion and the effects on bone remodeling. METHODS: Palatal expansion model and macrophage depletion model were established. Micro-CT, histological staining, and immunohistochemical staining were used to investigate the changes in the number and phenotype of macrophages during palatal expansion as well as the effects on bone remodeling of the midpalatal suture. Additionally, the effect of mechanically induced M2 macrophages on palatal osteoblasts was also elucidated in vitro. RESULTS: The number of macrophages increased significantly and polarized toward M2 phenotype with the increase of the expansion time, which was consistent with the trend of bone remodeling. After macrophage depletion, the function of osteoblasts and bone formation at the midpalatal suture were impaired during palatal expansion. In vitro, conditioned medium derived from M2 macrophages facilitated osteogenic differentiation of osteoblasts and decreased the RANKL/OPG ratio. CONCLUSIONS: Macrophages through polarizing toward M2 phenotype participated in midpalatal suture bone remodeling during palatal expansion, which may provide a new idea for promoting bone remodeling from the perspective of regulating macrophage polarization.

A Streptococcus suis Strain Δcps/ssna-msly (P353L)-SC19 Provides Cross-Protection against Serotypes 2 and 9 Strain Challenges in a Mouse Model.

Streptococcus suis is an important zoonotic pathogen that mainly causes meningitis, septicemia, and arthritis. Due to the limited cross-protection between numerous serotypes, the existing inactive vaccines in clinical use fail to offer sufficient protection. In this study, a gene deletion-attenuated strain Δcps/ssna-msly (P353L)-SC-19 was constructed by deleting cps and ssna genes from the epidemic strain SC-19 with a mutation of SLY (P353L). The safety of Δcps/ssna-msly (P353L)-SC-19 was confirmed in both in vitro and in vivo experiments. We further demonstrated that immunization with Δcps/ssna-msly (P353L)-SC-19 induced significant cellular immunity and humoral immunity in mice and protected against infections caused by type 2 strain SC-19 (100% protection) and type 9 strain S29 (50% protection), while also preventing meningitis induced by S29. This study highlights the potential of using CPS-deficient strains to achieve cross-protection against different Streptococcus suis serotypes and develop a promising universal live vaccine.

Nerve growth factor promote osteogenic differentiation of dental pulp stem cells through MEK/ERK signalling pathways.

Nerve growth factor (NGF) and its receptor, tropomyosin receptor kinase A (TrkA), are known to play important roles in the immune and nervous system. However, the effects of NGF on the osteogenic differentiation of dental pulp stem cells (DPSCs) remain unclear. This study aimed to investigate the role of NGF on the osteogenic differentiation of DPSCs in vitro and the underlying mechanisms. DPSCs were cultured in osteogenic differentiation medium containing NGF (50 ng/mL) for 7 days. Then osteogenic-related genes and protein markers were analysed using qRT-PCR and Western blot, respectively. Furthermore, addition of NGF inhibitor and small interfering RNA (siRNA) transfection experiments were used to elucidate the molecular signalling pathway responsible for the process. NGF increased osteogenic differentiation of DPSCs significantly compared with DPSCs cultured in an osteogenic-inducing medium. The NGF inhibitor Ro 08-2750 (10 µM) and siRNA-mediated gene silencing of NGF receptor, TrkA and ERK signalling pathways inhibitor U0126 (10 µM) suppressed osteogenic-related genes and protein markers on DPSCs. Furthermore, our data revealed that NGF-upregulated osteogenic differentiation of DPSCs may be associated with the activation of MEK/ERK signalling pathways via TrkA. Collectively, NGF was capable of promoting osteogenic differentiation of DPSCs through MEK/ERK signalling pathways, which may enhance the DPSCs-mediated bone tissue regeneration.

Isolation, identification, molecular and pathogenicity characteristics of an infectious laryngotracheitis virus from Hubei province, China.

Multiple outbreaks of avian infectious laryngotracheitis (ILT) in chickens, both domestically and internationally, have been directly correlate to widespread vaccine use in affected countries and regions. Phylogenetic and recombination event analyses have demonstrated that avian infectious laryngotracheitis virus (ILTV) field strains are progressively evolving toward the chicken embryo-origin (CEO) vaccine strain. Even with standardized biosecurity measures and effective prevention and control strategies implemented on large-scale farms, continuous ILT outbreaks result in significant economic losses to the poultry industry worldwide. These outbreaks undoubtedly hinder efforts to control and eradicate ILTV in the future. In this study, an ILTV isolate was successfully obtained by laboratory PCR detection and virus isolation from chickens that exhibited dyspnea and depression on a broiler farm in Hubei Province, China. The isolated strain exhibited robust propagation on chorioallantoic membranes of embryonated eggs, but failed to establish effective infection in chicken hepatocellular carcinoma (LMH) cells. Phylogenetic analysis revealed a unique T441P point mutation in the gJ protein of the isolate. Animal experiments confirmed the virulence of this strain, as it induced mortality in 6-wk-old chickens. This study expands current understanding of the epidemiology, genetic variations, and pathogenicity of ILTV isolates circulating domestically, contributing to the elucidate of ILTV molecular basis of pathogenicity and development of vaccine.

Mechanical force induces mitophagy-mediated anaerobic oxidation in periodontal ligament stem cells.

BACKGROUND: The preference for glucose oxidative mode has crucial impacts on various physiological activities, including determining stem cell fate. External mechanical factors can play a decisive role in regulating critical metabolic enzymes and pathways of stem cells. Periodontal ligament stem cells (PDLSCs) are momentous effector cells that transform mechanical force into biological signals during the reconstruction of alveolar bone. However, mechanical stimuli-induced alteration of oxidative characteristics in PDLSCs and the underlying mechanisms have not been fully elucidated. METHODS: Herein, we examined the expression of LDH and COX4 by qRT-PCR, western blot, immunohistochemistry and immunofluorescence. We detected metabolites of lactic acid and reactive oxygen species for functional tests. We used tetramethylrhodamine methyl ester (TMRM) staining and a transmission electron microscope to clarify the mitochondrial status. After using western blot and immunofluorescence to clarify the change of DRP1, we further examined MFF, PINK1, and PARKIN by western blot. We used cyclosporin A (CsA) to confirm the regulation of mitophagy and ceased the stretching as a rescue experiment. RESULTS: Herein, we ascertained that mechanical force could increase the level of LDH and decrease the expression of COX4 in PDLSCs. Simultaneously, the yield of reactive oxygen species (ROS) in PDLSC reduced after stretching, while lactate acid augmented significantly. Furthermore, mitochondrial function in PDLSCs was negatively affected by impaired mitochondrial membrane potential (MMP) under mechanical force, and the augment of mitochondrial fission further induced PRKN-dependent mitophagy, which was confirmed by the rescue experiments via blocking mitophagy. As a reversible physiological stimulation, the anaerobic preference of PDLSCs altered by mechanical force could restore after the cessation of force stimulation. CONCLUSIONS: Altogether, our study demonstrates that PDLSCs under mechanical force preferred anaerobic oxidation induced by the affected mitochondrial dynamics, especially mitophagy. Our findings support an association between mechanical stimulation and the oxidative profile of stem cells, which may shed light on the mechanical guidance of stem cell maintenance and commitment, and lay a molecular foundation for periodontal tissue regeneration.

Small Extracellular Vesicles from Periodontal Ligament Stem Cells Primed by Lipopolysaccharide Regulate Macrophage M1 Polarization via miR-433-3p Targeting TLR2/TLR4/NF-κB.

Lipopolysaccharide (LPS) is regarded as the main pathogenic factor of periodontitis. Mesenchymal stem cell-derived small extracellular vesicles (sEVs) play a key role in a variety of physiological and pathological processes. This study investigated the effects of sEVs derived from periodontal ligament stem cells (PDLSCs) pretreated with LPS on macrophage polarization and the underlying mechanisms. PDLSCs were treated with LPS (1 µg/mL) for 24 h, and sEVs were harvested by gradient centrifugation method. Macrophages were incubated with sEVs for 24 h, followed by examination of the expression profiles of inflammatory and anti-inflammatory cytokines, and polarization markers. Furthermore, microarray analysis, western blot test, and microRNA inhibitor transfection experiments were used to elucidate the molecular signaling pathway responsible for the process. The results showed that sEVs derived from LPS-preconditioning PDLSCs could significantly increase the expression of M1 markers and inflammatory cytokines, whereas decreased the expression of M2 markers and anti-inflammatory cytokines. Mechanistic analysis showed that TLR2/TLR4/NF-κB p65 pathway was involved in M1 polarization of macrophages, and microRNA-433-3p played a role, at least in part, in the course. Collectively, LPS could promote the macrophages into M1 status via TLR2/TLR4/NF-κB p65 signaling pathway partly by sEV-mediated microRNA-433-3p, which could be a potential therapeutic target for periodontitis.

Three-Dimensional Evaluation Effects of Microimplant-Assisted Rapid Palatal Expansion on the Upper Airway Volume: A Systematic Review and Meta-Analysis.

Microimplant-assisted rapid palatal expansion is increasingly used clinically; however, the effect on the upper airway volume in patients with maxillary transverse deficiency has not been thoroughly evaluated yet. The following electronic databases were searched up to August 2022: Medline via Ovid, Scopus, Embase, Web of Science, Cochrane Library, Google Scholar, and ProQuest. The reference lists of related articles were also reviewed by manual search. The Revised Cochrane Risk of Bias Tool for randomized trials (ROB2) and the Risk of Bias in non-randomized Studies of Interventions (ROBINS-I) tool were used to evaluate the risks of bias of the included studies. The mean differences (MD) and 95% confidence intervals (CI) of changes in nasal cavity and upper airway volume were analyzed using a random-effects model, and subgroup and sensitivity analyses were also performed. Two reviewers independently completed the process of screening studies, extracting data, and assessing the quality of studies. In total, twenty-one studies met the inclusion criteria. After assessing the full texts, only thirteen studies were included, with nine studies selected for quantitative synthesis. Oropharynx volume increased significantly after immediate expansion (WMD: 3156.84; 95% CI: 83.63, 6230.06); however, there was no significant change in nasal volume (WMD: 2527.23; 95% CI: -92.53, 5147.00) and nasopharynx volume (WMD: 1138.29; 95% CI: -52.04, 2328.61). After retention a period, significant increases were found in nasal volume (WMD: 3646.27; 95% CI: 1082.77, 6209.77) and nasopharynx volume (WMD: 1021.10; 95% CI: 597.11, 1445.08). However, there was no significant change after retention in oropharynx volume (WMD: 789.26; 95% CI: -171.25, 1749.76), palatopharynx volume (WMD: 795.13; 95% CI: -583.97, 2174.22), glossopharynx volume (WMD: 184.50; 95% CI: -1745.97, 2114.96), and hypopharynx volume (WMD: 39.85; 95% CI: -809.77, 889.46). MARPE appears to be linked with long-term increases in nasal and nasopharyngeal volume. However, high-quality clinical trials are required to further verify the effects of MARPE treatment on the upper airway.

Near-Infrared Ratiometric Hemicyanine-Based pH Fluorescence Probe with Bone Targetability for Monitoring Bone Resorption.

Accurate detection of bone resorption is extremely important in the orthodontic treatment process as it can provide a basis for clinical treatment strategies. Recently, pH-responsive fluorescence probes have received tremendous attention in bone resorption monitoring owing to their high sensitivity, good specificity, and in situ and real-time detection capabilities, but there are still some shortcomings like the increase in the risk of osteonecrosis of the jaw by use of bisphosphonate as the bone-targeting moiety and the insufficient monitoring accuracy due to susceptibility to interference. Herein, we designed and synthesized a near-infrared ratiometric hemicyanine-based pH fluorescence probe (Hcy-Asp6) with fluorescence-imaging and pH-determining capabilities, and bone targetability for more reliably and safely monitoring the bone resorption in orthodontic treatment. In vitro optical performance tests of Hcy-Asp6 revealed that the probe had high sensitivity, excellent photostability, reversibility, and strong resistance to interference, and the probe suggested excellent bone-binding ability and biocompatibility in the bone-targeting evaluation and the cytotoxicity test. Furthermore, in vitro and in vivo bone resorption monitoring assays demonstrated that this probe can detect bone resorption by fluorescence imaging and quantitative monitoring of pH associated with the bone resorption. Thus, the results indicated that this probe possessing bone targetability and accurate bone resorption-monitoring capability has an extraordinarily great clinical potential to be employed for real-time monitoring of bone resorption in orthodontic treatment and could also serve as a reference in bone resorption monitoring for other bone resorption-related diseases.

Mechanical Force Modulates Alveolar Bone Marrow Mesenchymal Cells Characteristics for Bone Remodeling during Orthodontic Tooth Movement through Lactate Production.

Orthodontic tooth movement (OTM) relies on mechanical force-induced bone remodeling. As a metabolic intermediate of glycolysis, lactate has recently been discovered to participate in bone remodeling by serving as a signaling molecule. However, whether lactate could respond to mechanical stimulus during OTM, as well as whether lactate has an impact on the alveolar bone remodeling during orthodontics, remain to be further elucidated. In the current study, we observed physiologically elevated production of lactate along with increased osteogenic differentiation, proliferation, and migration of alveolar bone marrow mesenchymal cells (ABMMCs) under mechanical force. Inhibition of lactate, induced by cyclic mechanical stretch by GNE-140, remarkably suppressed the osteogenic differentiation, proliferation, and migration, yet enhanced apoptosis of ABMMCs. Mechanistically, these regulatory effects of lactate were mediated by histone lactylation. Taken together, our results suggest that force-induced lactate is involved in controlling bone remodeling-related cellular activities in ABMMCs and plays a vital role in the alveolar bone remodeling during OTM. Our findings indicate that lactate might be a critical modulator for alveolar bone remodeling during OTM, providing a novel therapeutic target for the purpose of more effectively controlling tooth movement and improving the stability of orthodontic results.

[Research Progress of Mesenchymal Stem Cells and Their Exosomes on Tumors].

In China, malignant tumor is the main cause of death in both urban and rural areas. Mesenchymal stem cells (MSCs) have multidirectional differentiation potential, self-renewal ability and good immunomodulatory properties. Exosomes, as important paracrine substances of MSCs, mediate information exchange and transmission between cells in tumor microenvironment and influence the occurrence and development of tumors. Recently, conflicting findings have been reported on the effects of MSCs and their exosomes on tumors. On the one hand, MSCs and their exosomes are tumorigenic and can target specific sites to inhibit tumor growth; On the other hand, there is also evidence that MSCs could affect tumor growth and migration as part of the tumor microenvironment. In this paper, we will review the relationship between MSCs and exosomes and tumorgenesis and development, as well as how MSCs and exosomes play different roles in tumorgenesis and development, in order to provide beneficial help for tumor diagnosis, prognosis and precise treatment.
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