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Flat bands in 2D twisted materials are key to the realization of correlation-related exotic phenomena. However, a flat band often was achieved in the large system with a very small twist angle, which enormously increases the computational and experimental complexity. In this work, we proposed group-V twisted bilayer materials, including P, As, and Sb in the ß phase with large twist angles. The band structure of twisted bilayer materials up to 2524 atoms has been investigated by a deep learning method DeepH, which significantly reduces the computational time. Our results show that the bandgap and the flat bandwidth of twisted bilayer ß-P, ß-As, and ß-Sb reduce gradually with the decreasing of twist angle, and the ultra-flat band with bandwidth approaching 0 eV is achieved. Interestingly, we found that a twist angle of 9.43° is sufficient to achieve the band flatness for ß-As comparable to that of twist bilayer graphene at the magic angle of 1.08°. Moreover, we also find that the bandgap reduces with decreasing interlayer distance while the flat band is still preserved, which suggests interlayer distance as an effective routine to tune the bandgap of flat band systems. Our research provides a feasible platform for exploring physical phenomena related to flat bands in twisted layered 2D materials.
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In the repair of maxillofacial bone defects, autogenous craniofacial bone can often provide superior clinical results over long bone grafts. Most current studies have focused on the osteogenic differences between alveolar bone marrow (ABM) and long bone marrow (LBM), however, studies about the angiogenic differences between the two are currently lacking. We downloaded single-cell RNA sequencing (scRNA-seq) of mouse ABM and LBM respectively from the public database, and the data were processed by using Seurat package. CellphoneDB2 results showed that macrophages had the strongest interaction with mesenchymal stem cells (MSCs) and endothelial cells (ECs). ELISA results confirmed that ABM macrophages secreted a higher level of vascular endothelial growth factor A (Vegfa) compared to LBM macrophages, which further promoted angiogenesis of ECs and MSCs. Using SCENIC package, six key transcription factors (TFs) were identified to regulate the difference between ABM and LBM macrophages, and activating transcription factor 4 (Atf4) was confirmed to be more expressed in ABM macrophages by polymerase chain reaction (PCR) and western blot (WB), with predicted target genes including Vegfa. Besides, the result of scRNA-seq implied ABM macrophages more in M1 status than LBM macrophages, which was confirmed by the following experiments. From the results of another assay for transposase accessible chromatin sequencing (ATAC-seq) and RNA-seq about M1 macrophages, Atf4 was also confirmed to regulate the M1 polarization. So, we suspected that Atf4 regulated the different expression of Vegfa between ABM and LBM macrophages by activating M1 polarization. After knocking down Atf4, the expression of M1 polarization markers and Vegfa were downregulated and vasculogenic differences were eliminated, which were subsequently reversed by the addition of LPS/IFN-γ. Our study might provide a new idea to improve the success rate of autologous bone grafting and treatment of oral diseases.
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Fator 4 Ativador da Transcrição , Fator A de Crescimento do Endotélio Vascular , Animais , Camundongos , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Sequenciamento de Cromatina por Imunoprecipitação , Células Endoteliais/metabolismo , Macrófagos/metabolismo , RNA/metabolismo , RNA-Seq , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
INTRODUCTION: This retrospective clinical study investigated the clinical changes of maxillary central incisor and alveolar bone in Class II Division 2 nonextraction treatment with fixed appliances or clear aligners on the basis of cone-beam computed tomography. METHODS: Fifty-nine Chinese Han patients with similar demographic characteristics were collected from a conventional bracket group, a self-ligating bracket group, and a clear aligner group. All measurements about root resorption and alveolar bone thickness on the cone-beam computed tomography images were tested. Changes between pretreatment and posttreatment were evaluated by paired-sample t test. The variation among the 3 groups was compared by 1-way analysis of variance. RESULTS: The resistance center of the maxillary central incisor showed upward or forward movement, and the axial inclination was increased in 3 groups (P <0.0001). Root volume loss in the clear aligner group (23.68 ± 4.82 mm3) was significantly less than that in the fixed appliances group (28.24 ± 6.44 mm3 in the conventional bracket group, 28.17 ± 6.07 mm3 in the self-ligating bracket group) (P <0.05). All 3 groups showed a significant decrease in palatal alveolar bone and total bone thickness at all 3 levels at posttreatment. In contrast, labial bone thickness significantly increased except for crestal level l. Among the 3 groups, the clear aligner group had a prominent increase in labial bone thickness at the apical level (P = 0.0235). CONCLUSIONS: Clear aligner treatment for Class II Division 2 malocclusions could effectively reduce the incidence of fenestration and root resorption. Our findings will be beneficial to comprehensively understand the effectiveness of different appliances for Class II Division 2 malocclusions treatment.
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Má Oclusão Classe II de Angle , Aparelhos Ortodônticos Removíveis , Reabsorção da Raiz , Humanos , Incisivo/diagnóstico por imagem , Estudos Retrospectivos , Má Oclusão Classe II de Angle/diagnóstico por imagem , Má Oclusão Classe II de Angle/terapia , Aparelhos Ortodônticos Fixos , Tomografia Computadorizada de Feixe Cônico , Maxila/diagnóstico por imagemRESUMO
PURPOSE: To compare a novel vacuum suction ureteroscopic laser lithotripsy (VS-URS) with traditional ureteroscopic laser lithotripsy (T-URS) for impacted upper ureteral stones and to better define the potential benefits of VS-URS. METHODS: Between May 2019 and March 2021, 158 patients with impacted upper ureteral stones underwent ureteroscopic holmium-YAG laser lithotripsy. Of these, 76 underwent VS-URS and 82 underwent T-URS. In VS-URS procedures, the vacuum suction device is composed of a 5F ureteral catheter and a tee joint. The ureteral catheter is linked to the vacuum aspirator by the sidearm of the tee joint, and a 200 µm fiber is inserted through the tee joint and the ureteral catheter into the stone site for lithotripsy. RESULTS: When compared to the T-URS group, the VS-URS group had a shorter mean operation time (38.18 ± 6.37 min vs. 46.65 ± 5.66 min; P = 0.000), lower fever rate (3.9% vs. 14.6%; P < 0.022), less stone retropulsion (5.3% vs. 18.3%; P = 0.012), lower extra management rate (6.58% vs. 21.95%; P = 0.006), and a higher stone-free rate of the first postoperative day (88.2% vs. 72.0%; P = 0.011). There were no significant differences in stone-free rates 1 month after surgery between groups (94.7% vs. 92.7%; P = 0.748). CONCLUSIONS: VS-URS is an effective modality for impacted upper ureteral stones, and has a shorter operating time, lower fever rate, less stone retropulsion, and a higher primary stone-free rate compared with T-URS.
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Litotripsia a Laser , Litotripsia , Cálculos Ureterais , Humanos , Litotripsia/métodos , Litotripsia a Laser/métodos , Sucção , Resultado do Tratamento , Cálculos Ureterais/cirurgia , Ureteroscopia/métodos , VácuoRESUMO
Mechanical force across sutures is able to promote suture osteogenesis. Orthodontic clinics often use this biological characteristic of sutures to treat congenital cranio-maxillofacial malformations. However, the underlying mechanisms still remain poorly understood. Craniofacial sutures provide a special growth source and support primary sites of osteogenesis. Here, we isolated rat sagittal suture cells (rSAGs), which had mesenchymal stem cell characteristics and differentiating abilities. Cells were then subjected to mechanical tension (5% elongation, 0.5 Hz; sinusoidal waveforms) showing that mechanical tension could enhance osteogenic differentiation but hardly affect proliferation of rSAGs. Besides, mechanical tension could increase Rho-associated kinase (ROCK) expression and enhance transcriptional coactivator with PDZ-binding motif (TAZ) nuclear translocation. Inhibiting ROCK expression could suppress tension-induced osteogenesis and block tension-induced upregulation of nuclear TAZ. In addition, our results indicated that TAZ had direct combination sites with runt-related transcription factor 2 (Runx2) in rSAGs, and knock-downed TAZ simultaneously decreased the expression of Runx2 no matter with or without mechanical tension. In summary, our findings demonstrated that the multipotency of rSAGs in vitro could give rise to early osteogenic differentiation under mechanical tension, which was mediated by ROCK-TAZ signal axis.
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Subunidade alfa 1 de Fator de Ligação ao Core/genética , Suturas Cranianas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Osteogênese/genética , Transativadores/genética , Quinases Associadas a rho/genética , Animais , Diferenciação Celular/genética , Suturas Cranianas/crescimento & desenvolvimento , Suturas Cranianas/patologia , Fenômenos Mecânicos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Ratos , Transdução de Sinais/genética , Proteínas com Motivo de Ligação a PDZ com Coativador TranscricionalRESUMO
Osteocytes sense extracellular mechanical stimuli and transduce them into biochemical signals to regulate bone remodeling. The function is also evidenced in orthodontic tooth movement. But the underlying mechanisms haven't been clarified. Autophagy is an evolutionarily conserved cellular catabolic process which affects cellular secretory capabilities. We hypothesized that mechanical force activated osteocyte autophagy through TFE3-related signaling and further promoted osteocyte-mediated osteoclastogenesis. In the present study, we demonstrated that osteocyte autophagy was activated under mechanical compressive force using murine orthodontic tooth movement model since the number of LC3B-positive osteocytes increased by 3-fold in the compression side. In addition, both in vitro mechanical compression and chemical autophagy agonist increased the secretion of RANKL in osteocytes by 3-fold and 4-fold respectively, which is a crucial cytokine for osteoclastogenesis. Lastly, conditioned medium collected from compressed osteocytes promoted the development of osteoclasts. These results suggest that osteocytes could promote osteoclastogenesis via autophagy-mediated RANKL secretion under mechanical compressive force. Our research might provide evidence for exploring methods to accelerate tooth movement in clinic.
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Autofagia/fisiologia , Osteócitos/metabolismo , Osteogênese/fisiologia , Ligante RANK/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Linhagem Celular , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais/fisiologia , Estresse Mecânico , Técnicas de Movimentação DentáriaRESUMO
Designing smart scaffolds to reduce administration dosage under the premise of functional healing of bone defects to avoid the severe side effects associated with BMP-2 treatments is one of the essential goals in bone tissue engineering. Here, we report a novel biodegradable PLGA/PSBMA composite as the scaffold for bone tissue engineering. The introduction of zwitterionic PSBMA components can alter the intrinsic burst degradation behavior of PLGA and enable a sustained degradation of the scaffold over the time. The PLGA/PSBMA scaffold can sequester rhBMP-2 and enable a sustained release of the sequestered rhBMP-2 with preserved bioactivity. Furthermore, PLGA/PSBMA scaffolds were able to guide robust healing of critical-sized nonunion calvarial defects (5 mm) at an ultralow dose of 400 ng/scaffold, at which level successful healing of critical-sized bone defects has never been reported. These findings indicate the PLGA/PSBMA scaffolds as novel high-efficiency rhBMP-2 delivery vehicles for bone tissue engineering, and the concept of utilizing the material, which is capable of maintaining the bioactivity of the proteins in the preparation of scaffolds, may open a new avenue for the design of smart scaffolds/vehicles for high-efficiency protein/bioactive drug therapies.
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Regeneração Óssea , Alicerces Teciduais , Animais , Proteína Morfogenética Óssea 2 , Osso e Ossos , Osteogênese , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Ratos , Proteínas Recombinantes , Engenharia TecidualRESUMO
2D ferromagnets, such as CrX3 (X = Cl, Br and I), have been attracting extensive attention since they provide novel platforms to fundamental physics and device applications. Integrating CrX3 with other electrodes and substrates is an essential step to their device realization. Therefore, it is important to understand the interfacial properties between CrX3 and other 2D materials. As an illustrative example, we have investigated the heterostructures between CrX3 and graphene (CrX3/Gr) by first-principles calculations. We found a unique Schottky contact type with strongly spin-dependent barriers in CrX3/Gr. This can be understood by synergistic effects between the exchange splitting of the semiconductor band of CrX3 and interlayer charge transfer. The spin-asymmetry of Schottky barriers may result in different tunneling rates of spin-up and down electrons, and then lead to spin-polarized current, namely the spin-filter (SF) effect. Moreover, by introducing X vacancies into CrX3/Gr, an ohmic contact forms in the spin-up direction. It may enhance the transport of spin-up electrons, and improve the SF effect. Our systematic study reveals the unique interfacial properties of CrX3/Gr, and provides a theoretical view of the understanding and designing of spintronic devices based on magnetic vdW heterostructures.
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OBJECTIVE: To study the application of ponderal index (PI), body mass index (BMI), mid-arm circumference/head circumference (MAC/HC), and Clinical Assessment of Nutritional Status (CANS) score in assessing the nutritional status of neonates at birth, and to find a simple and reliable scheme for the assessment of fetal nutritional status. METHODS: PI, BMI, MAC/HC, and CANS were used to assess the nutritional status of full-term infants and preterm infants shortly after birth. The assessment results of these methods were analyzed. RESULTS: Among the 678 full-term infants, 61, 102, 47, and 131 were diagnosed with malnutrition by PI, BMI, MAC/HC, and CANS respectively. Among the 140 preterm infants, 30, 87, 9, and 112 were diagnosed with malnutrition by PI, BMI, MAC/HC, and CANS respectively. The combination of BMI and CANS had a detection rate of 99.3% in full-term infants and 100% in preterm infants. Compared with the single method, the combination significantly improved the detection rate of malnutrition (P < 0.05), while there was no significant difference between the combination of BMI+CANS and the combination of PI+BMI+CANS (P > 0.05). CONCLUSIONS: The combination of BMI+CANS can reduce the rate of missed diagnosis of fetal malnutrition. It is therefore a simple and reliable method for the assessment of fetal malnutrition.
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Transtornos da Nutrição Fetal/diagnóstico , Avaliação Nutricional , Índice de Massa Corporal , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Estado NutricionalRESUMO
The recent experimental discovery of intrinsic ferromagnetism in single-layer CrI3 opens a new avenue to low-dimensional spintronics. However, the low Curie temperature, TC â¼ 45 K, is still a large obstacle to its realistic device application. In this work, we demonstrate that the TC and magnetic moment of CrX3 (X = Br, I) can be enhanced simultaneously by coupling them to buckled two-dimensional Mene (M = Si, Ge) to form magnetic van der Waals (vdW) heterostructures. Our first-principles calculations reveal that n-doping of CrX3, induced by a significant spin-dependent interlayer charge-transfer from Mene, is responsible for the drastic enhancement of TC and magnetic moment. Furthermore, the diversified electronic properties including half-metallicity and semi-conductivity with a configuration-dependent energy gap are also predicted in this novel vdW heterostructure, implying broad potential applications in spintronics. Our study suggests that vdW engineering may be an efficient way to tune the magnetic properties of 2D magnets, and Mene/CrX3 magnetic vdW heterostructures are wonderful candidates in spintronics and nanoelectronics devices.
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Type-II van der Waals (vdW) heterostructures are considered as a class of competitive candidates of high-efficiency photovoltaic materials, due to their spontaneous electron-hole separation. However, most of the vdW heterostructures possess an indirect gap and a large band offset, which would lead to low photon-to-electron conversion efficiency. Taking an SbI3/BiI3 vdW heterostructure as an illustrative example, we propose interlayer compression and vertical electric field application as two effective strategies to modulate the electronic and photovoltaic properties of type-II vdW heterostructures. Our results reveal that a lattice-matched SbI3/BiI3 vdW heterostructure has an indirect band gap of 1.34 eV with the conduction band minimum (CBM) at the Γ point and the valence band maximum (VBM) between the Γ and M points. The power conversion efficiency (PCE) of an SbI3/BiI3-based excitonic solar cell (XSC) is predicted to be about 14.42%. When compressing the heterostructure along the vdW gap direction, the highest valence band state at the Γ point is lifted significantly and the VBM gradually approaches the Γ point, implying an indirect-direct gap transition. This interesting evolution can be attributed to the increasing k-dependent electronic hybridization of the pz orbitals of interlayer adjacent I atoms with a reduced interlayer distance. Moreover, the interlayer compression also enhances the PCE of the system monotonically. When applying a vertical electric field, the band alignment of the heterostructure undergoes a transition from type-II to type-I and then returns to type-II between 0.1 and 0.6 V Å-1. Meanwhile, the PCE of the SbI3/BiI3 XSC could be enhanced up to 21.63%. This work provides guidance for improving the electronic and photovoltaic properties of type-II vdW heterostructures.
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A simple, rapid and low-cost determination method of benzo(a)pyrene in fried and baked foods was proposed by high performance liquid chromatography combined with vesicular coacervative supramolecular solvent (SUPRAS) extraction. The vesicular coacervate was composed of 1-octanol and tetrabutylammonium bromide. 200 mg of dried samples with 600 µL SUPRAS could be mixed to extract benzo(a)pyrene. Neither evaporation nor further clean-up steps for the extracts were needed. The overall sample treatment took approximately 30 min, and several samples could be simultaneously treated using conventional lab equipment. Then, benzo(a)pyrene was analyzed via liquid chromatography-fluorescence detection. Parameters affecting the extraction efficiency were investigated and optimized. The results showed good linearity of benzo(a)pyrene with the coefficients of determination (R 2) of more than 0.9999 in the range of 0.1-50.0 µg/kg. The limit of detection of the method was 0.11 µg/kg. Recoveries for spiked samples in the range of 1-10 µg/kg were between 89.86 and 100.01%, with relative standard deviations from 1.20 to 3.20%. Benzo(a)pyrene was present in food samples (including instant noodles, biscuits, rice crust and fried bread stick) at concentrations in the range of 0.08-0.39 µg/kg according to the proposed method. The proposed pretreatment method significantly reduces the analysis time. Furthermore, the solventless approach is in accordance with the green chemistry development trend and has significant application prospects.
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Recently, atomically thin organic-inorganic hybrid perovskites have been synthesized experimentally, which opens up new opportunities for exploring their novel properties in the 2D limit. Based on the comparative density functional theory calculation with and without spin-orbit coupling effects, the stability, electronic structure, and carrier mobility of the two-dimensional organic-inorganic hybrid perovskites MAPbI3 (MA = CH3NH3) have been investigated systemically. Two single-unit-cell-thick 2D MAPbI3 terminated by PbI2 and CH3NH3I are constructed, and their thermodynamic stabilities are also evaluated using the first-principles constrained thermodynamics method. Our results indicate that both 2D MAPbI3 with different terminations can be stable under certain conditions and have a suitable direct bandgap. Moreover, they are also found to have termination-dependent band edge and carrier mobility. The acoustic-phonon-limited carrier mobilities estimated using the deformation theory and effective mass approximation are on the order of thousands of square centimeters per volt per second and also highly anisotropic. These results indicate that 2D MAPbI3 are competitive candidates for low-dimensional photovoltaic applications.
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With a similar electronic structure as that of platinum, molybdenum carbide (Mo2C) holds significant potential as a high performance catalyst across many chemical reactions. Empirically, the precise control of particle size, shape, and surface nature during synthesis largely determines the catalytic performance of nanoparticles, giving rise to the need of clarifying the underlying growth characteristics in the nucleation and growth of Mo2C. However, the high-temperature annealing involved during the growth of carbides makes it difficult to directly observe and understand the nucleation and growth processes. Here, we report on the use of advanced in situ transmission electron microscopy with atomic resolution to reveal a three-stage mechanism during the growth of Mo2C nanoparticles over a wide temperature range: initial nucleation via a mechanism consistent with spinodal decomposition, subsequent particle coalescence and monomer attachment, and final surface faceting to well-defined particles with minimum surface energy. These microscopic observations made under a heating atmosphere offer new perspectives toward the design of carbide-based catalysts, as well as the tuning of their catalytic performances.
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RATIONALE: Diffusion of an analyte is one of the main determinants of reduced sensitivity in an electrospray ionization (ESI) source. In this work, the relative responses of compounds and their stable isotope-labeled (SIL) products in different injection modes were compared to investigate the diffusion behavior of analytes in ESI, without influence of other factors. METHODS: Chloramphenicol (CAP) and D5 -CAP as well as melamine (Mel) and (13) C3 -Mel were used to illustrate the diffusion behavior in different operation modes and different ion sources, by comparing their relative responses in infusion mode and flow injection analysis (FIA) mode under variable temperature. RESULTS: In infusion mode, sample solution was introduced by syringe, and formed a stable and continuous signal. While in FIA mode, because of the huge difference in volume between the sample solution and the mobile phase, it is assumed that analyte ionizes and transmits in the gaseous phase created by the mobile phase. Analytes formed different concentration distributions in the two injection modes. The relative responses of CAP and D5 -CAP increased from 0.81 to 0.98 when the temperature was increased from 300 °C to 650 °C in infusion mode and decreased from 1.37 to 1.17 with increasing temperature in FIA mode. The opposite trends of the two injection modes were also obtained in positive operation modes and ion sources with different configuration. CONCLUSIONS: Opposite variation tendencies of relative responses of model samples and their stable isotope-labeled products with temperature were observed for infusion and FIA injection modes, indicating different diffusion behaviors in the two injection modes. These results provide a theoretical basis for ion source designing and better understanding of the ESI mechanism. Copyright © 2016 John Wiley & Sons, Ltd.
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The interaction between graphene and Ni(111) surface has been investigated systematically by density functional theory calculations, in which two different functionals PBE and optB88-vdW are used. PBE calculation indicates no binding between graphene and Ni(111) surface, while optB88-vdW, which is evidenced to consider van der Waals interaction reasonably, predicts the correct binding picture. The accurate potential energy surfaces suggest that top-fcc, bridge-top, and top-hcp are possible stable structures of graphene on Ni(111) surface, which are also found to have very close energies, in agreement with coexistence of different phases found experimentally. Different from PBE, the optB88-vdW functional predicts that top-fcc is the most stable configuration, following by bridge-top and then top-hcp, which is consistent with the surface distribution given by a statistical analysis of high-resolution scanning tunneling microscopy (STM) images. The Dirac points are destroyed in chemisorbed phases of all stable structures. Further analysis indicates that strong hybridization between Ni-3d and C-2p orbitals and asymmetry induced by substrate are responsible for the gap opening at K point. The detailed binding mechanisms have been analysed using differential charge density and the STM images.
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Following the publication of the above article, a concerned reader drew to the Editor's attention that certain of the Transwell invasion assay data shown in Fig. 7B on p. 451 were strikingly similar to data that had appeared in Fig. 3D in a previously published paper written by different authors at a different research institute, which had been received at the journal Cancer Letters at around the same time, and which has subsequently been retracted [Gu J, Wang Y, Wang X, Zhou D, Shao C, Zhou M and He Z: Downregulation of lncRNA GAS5 confers tamoxifen resistance by activating miR222 in breast cancer. Cancer Lett 434: 110, 2018]. In addition, there were potentially anomalous features associated with the western blot and cell cycle data in this paper. In view of the fact that certain of the data in the above article were also submitted to a different journal within the space of a few days, the Editor of International Journal of Oncology has decided that this paper should be retracted from the publication. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Oncology 54: 443454, 2019; DOI: 10.3892/ijo.2018.4647].
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BACKGROUND: Craniofacial skeletal deformities can be addressed by applying tensile force to sutures to prompt sutural bone formation. The intricate process of mechanical modulation in craniofacial sutures involves complex biomechanical signal transduction. The small GTPase Ras homolog gene family member A (RhoA) functions as a key mechanotransduction protein, orchestrating the dynamic assembly of the cytoskeleton by activating the Rho-associated coiled-coil containing protein kinase (ROCK). Transcriptional coactivator with PDZ-binding motif (TAZ) serves as a crucial mediator in the regulation of genes and the orchestration of biological functions within the mechanotransduction signaling pathway. However, the role of RhoA/ROCK-TAZ in trans-sutural distraction osteogenesis has not been reported. METHODS: We utilized pre-osteoblast-specific RhoA deletion mice to establish an in vivo calvarial trans-sutural distraction model and an in vitro mechanical stretch model for pre-osteoblasts isolated from neonatal mice. Micro-CT and histological staining were utilized to detect the formation of new bone in the sagittal suture of the skull as well as the activation of RhoA, Osterix and TAZ. The activation of ROCK-limk-cofilin and the nuclear translocation of TAZ in pre-osteoblasts under mechanical tension were detected through Western blot, qRT-PCR, and immunofluorescence. RESULTS: The osteogenic differentiation of pre-osteoblasts was facilitated by mechanical tension through the activation of RhoA and Rho-associated kinase (ROCK), while ablation of RhoA impaired osteogenesis by inhibiting pre-osteoblast differentiation after suture expansion. Furthermore, inhibiting RhoA expression could block tensile-stimulated nuclear translocation of TAZ by preventing F-actin assembly through ROCK-LIM-domain kinase (LIMK)-cofilin pathway. In addition, the TAZ agonist TM-25659 could attenuate impaired osteogenesis caused by ablation of RhoA in pre-osteoblasts by increasing TAZ nuclear accumulation. CONCLUSIONS: This study demonstrates that mechanical stretching promotes the osteogenic differentiation of pre-osteoblasts in trans-sutural distraction osteogenesis, and this process is mediated by the RhoA/ROCK-TAZ signaling axis. Overall, our results may provide an insight for potential treatment strategies for craniosynostosis patients through trans-sutural distraction osteogenesis.
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Osteogênese por Distração , Osteogênese , Crânio , Quinases Associadas a rho , Proteína rhoA de Ligação ao GTP , Animais , Proteína rhoA de Ligação ao GTP/metabolismo , Quinases Associadas a rho/metabolismo , Camundongos , Crânio/metabolismo , Osteoblastos/metabolismo , Osteoblastos/citologia , Diferenciação Celular , Transdução de Sinais , Mecanotransdução Celular , Suturas Cranianas/metabolismo , Fator de Transcrição Sp7/metabolismo , Fator de Transcrição Sp7/genética , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional , Proteínas Adaptadoras de Transdução de SinalRESUMO
Protein A affinity chromatographic materials are widely used in clinical medicine and biomedicine because of their specific interactions with immunoglobulin G (IgG). Both the characteristics of the matrix, such as its structure and morphology, and the surface modification method contribute to the affinity properties of the packing materials. The specific, orderly, and oriented immobilization of protein A can reduce its steric hindrance with the matrix and preserve its bioactive sites. In this study, four types of affinity chromatographic materials were obtained using agarose and polyglycidyl methacrylate (PGMA) spheres as substrates, and multifunctional epoxy and maleimide groups were used to fix protein A. The effects of the ethylenediamine concentration, reaction pH, buffer concentration, and other conditions on the coupling efficiency of protein A and adsorption performance of IgG were evaluated. Multifunctional epoxy materials were prepared by converting part of the epoxy groups of the agarose and PGMA matrices into amino groups using 0.2 and 1.6 mol/L ethylenediamine, respectively. Protein A was coupled to the multifunctional epoxy materials using 5 mmol/L borate buffer (pH 8) as the reaction solution. When protein A was immobilized on the substrates by maleimide groups, the agarose and PGMA substrates were activated with 25% (v/v) ethylenediamine for 16 h to convert all epoxy groups into amino groups. The maleimide materials were then converted into amino-modified materials by adding 3 mg/mL 3-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS) dissolved in dimethyl sulfoxide (DMSO) and then suspended in 5 mmol/L borate buffer (pH 8). The maleimide groups reacted specifically with the C-terminal of the sulfhydryl group of recombinant protein A to achieve highly selective fixation on both the agarose and PGMA substrates. The adsorption performance of the affinity materials for IgG was improved by optimizing the bonding conditions of protein A, such as the matrix type, matrix particle size, and protein A content, and the adsorption properties of each affinity material for IgG were determined. The column pressure of the protein A affinity materials prepared using agarose or PGMA as the matrix via the maleimide method was subsequently evaluated at different flow rates. The affinity materials prepared with PGMA as the matrix exhibited superior mechanical strength compared with the materials prepared with agarose. Moreover, an excellent linear relationship between the flow rate and column pressure of 80 mL/min was observed for this affinity material. Subsequently, the effect of the particle size of the PGMA matrix on the binding capacity of IgG was investigated. Under the same protein A content, the dynamic binding capacity of the affinity materials on the PGMA matrix was higher when the particle size was 44-88 µm than when other particle sizes were used. The properties of the affinity materials prepared using the multifunctional epoxy and maleimide-modified materials were compared by synthesizing affinity materials with different protein A coupling amounts of 1, 2, 4, 6, 8, and 10 mg/mL. The dynamic and static binding capacities of each material for bovine IgG were then determined. The prepared affinity material was packed into a chromatographic column to purify IgG from bovine colostrum. Although all materials showed specific adsorption selectivity for IgG, the affinity material prepared by immobilizing protein A on the PGMA matrix with maleimide showed significantly better performance and achieved a higher dynamic binding capacity at a lower protein grafting amount. When the protein grafting amount was 15.71 mg/mL, the dynamic binding capacity of bovine IgG was 32.23 mg/mL, and the dynamic binding capacity of human IgG reached 54.41 mg/mL. After 160 cycles of alkali treatment, the dynamic binding capacity of the material reached 94.6% of the initial value, indicating its good stability. The developed method is appropriate for the production of protein A affinity chromatographic materials and shows great potential in the fields of protein immobilization and immunoadsorption material synthesis.
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Cromatografia de Afinidade , Proteína Estafilocócica A , Cromatografia de Afinidade/métodos , Proteína Estafilocócica A/química , Adsorção , Imunoglobulina G/química , Ácidos Polimetacrílicos/química , Sefarose/químicaRESUMO
Background: Predicting the outcome of oral squamous cell carcinoma (OSCC) is challenging due to its diverse nature and intricate causes. This research explores how lysosome-associated genes (LRGs) might forecast overall survival (OS) and correlate with immune infiltration in OSCC patients. Methods: We analyzed OSCC patients' LRGs' mRNA expression data and clinical details from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). Through univariate Cox regression, we pinpointed LRGs with prognostic potential. A signature comprising 12 LRGs linked to prognosis was developed via the Least Absolute Shrinkage and Selection Operator (LASSO) in a training dataset. Patients were classified as higher or lower risk based on their risk scores, and the prognostic independence of the risk score was assessed using multivariate analysis. The model's robustness and precision were confirmed through bioinformatics in the GEO test set. Differential gene expression analysis between risk groups highlighted functional disparities, while various immune evaluation methods elucidated immune differences. Results: The prognostic framework utilized 12 LRGs (SLC46A3, MANBA, NEU1, SDCBP, BRI3, TMEM175, CD164, GPC1, SFTPB, TPP1, Biglycan (BGN) and TMEM192), showing that higher risk was associated with poorer OS. This set of genes independently predicted OS in OSCC, linking LRGs to cellular adhesion and extracellular matrix involvement. Initial assessments using ssGSEA and CIBERSORT suggested that the adverse outcomes in the higher-risk cohort may be tied to immune system deregulation. Conclusion: Twelve-LRGs signature has been identified for OSCC prognosis prediction, offering novel directions for lysosome-targeted therapies against OSCC.