Hedgehog signaling regulates bone homeostasis through orchestrating osteoclast differentiation and osteoclast-osteoblast coupling.

Imbalance of bone homeostasis induces bone degenerative diseases such as osteoporosis. Hedgehog (Hh) signaling plays critical roles in regulating the development of limb and joint. However, its unique role in bone homeostasis remained largely unknown. Here, we found that canonical Hh signaling pathway was gradually augmented during osteoclast differentiation. Genetic inactivation of Hh signaling in osteoclasts, using Ctsk-Cre;Smof/f conditional knockout mice, disrupted both osteoclast formation and subsequent osteoclast-osteoblast coupling. Concordantly, either Hh signaling inhibitors or Smo/Gli2 knockdown stunted in vitro osteoclast formation. Mechanistically, Hh signaling positively regulated osteoclast differentiation via transactivation of Traf6 and stabilization of TRAF6 protein. Then, we identified connective tissue growth factor (CTGF) as an Hh-regulatory bone formation-stimulating factor derived from osteoclasts, whose loss played a causative role in osteopenia seen in CKO mice. In line with this, recombinant CTGF exerted mitigating effects against ovariectomy induced bone loss, supporting a potential extension of local rCTGF treatment to osteoporotic diseases. Collectively, our findings firstly demonstrate that Hh signaling, which dictates osteoclast differentiation and osteoclast-osteoblast coupling by regulating TRAF6 and CTGF, is crucial for maintaining bone homeostasis, shedding mechanistic and therapeutic insights into the realm of osteoporosis.

Primary bone tumor detection and classification in full-field bone radiographs via YOLO deep learning model.

OBJECTIVES: Automatic bone lesions detection and classifications present a critical challenge and are essential to support radiologists in making an accurate diagnosis of bone lesions. In this paper, we aimed to develop a novel deep learning model called You Only Look Once (YOLO) to handle detecting and classifying bone lesions on full-field radiographs with limited manual intervention. METHODS: In this retrospective study, we used 1085 bone tumor radiographs and 345 normal bone radiographs from two centers between January 2009 and December 2020 to train and test our YOLO deep learning (DL) model. The trained model detected bone lesions and then classified these radiographs into normal, benign, intermediate, or malignant types. The intersection over union (IoU) was used to assess the model's performance in the detection task. Confusion matrices and Cohen's kappa scores were used for evaluating classification performance. Two radiologists compared diagnostic performance with the trained model using the external validation set. RESULTS: In the detection task, the model achieved accuracies of 86.36% and 85.37% in the internal and external validation sets, respectively. In the DL model, radiologist 1 and radiologist 2 achieved Cohen's kappa scores of 0.8187, 0.7927, and 0.9077 for four-way classification in the external validation set, respectively. The YOLO DL model illustrated a significantly higher accuracy for intermediate bone tumor classification than radiologist 1 (95.73% vs 88.08%, p = 0.004). CONCLUSIONS: The developed YOLO DL model could be used to assist radiologists at all stages of bone lesion detection and classification in full-field bone radiographs. KEY POINTS: • YOLO DL model can automatically detect bone neoplasms from full-field radiographs in one shot and then simultaneously classify radiographs into normal, benign, intermediate, or malignant. • The dataset used in this retrospective study includes normal bone radiographs. • YOLO can detect even some challenging cases with small volumes.

Pericyte-derived exosomal miR-210 improves mitochondrial function and inhibits lipid peroxidation in vascular endothelial cells after traumatic spinal cord injury by activating JAK1/STAT3 signaling pathway.

BACKGROUND: Spinal cord injury (SCI) remains a significant health concern, with limited available treatment options. This condition poses significant medical, economic, and social challenges. SCI is typically categorized into primary and secondary injuries. Inflammation, oxidative stress, scar formation, and the immune microenvironment impede axon regeneration and subsequent functional restoration. Numerous studies have shown that the destruction of the blood-brain barrier (BBB) and microvessels is a crucial factor in severe secondary injury. Additionally, reactive oxygen species (ROS)-induced lipid peroxidation significantly contributes to endothelial cell death. Pericytes are essential constituents of the BBB that share the basement membrane with endothelial cells and astrocytes. They play a significant role in the establishment and maintenance of BBB. RESULTS: Immunofluorescence staining at different time points revealed a consistent correlation between pericyte coverage and angiogenesis, suggesting that pericytes promote vascular repair via paracrine signaling. Pericytes undergo alterations in cellular morphology and the transcriptome when exposed to hypoxic conditions, potentially promoting angiogenesis. We simulated an early ischemia-hypoxic environment following SCI using glucose and oxygen deprivation and BBB models. Co-culturing pericytes with endothelial cells improved barrier function compared to the control group. However, this enhancement was reduced by the exosome inhibitor, GW4869. In vivo injection of exosomes improved BBB integrity and promoted motor function recovery in mice following SCI. Subsequently, we found that pericyte-derived exosomes exhibited significant miR-210-5p expression based on sequencing analysis. Therefore, we performed a series of gain- and loss-of-function experiments in vitro. CONCLUSION: Our findings suggest that miR-210-5p regulates endothelial barrier function by inhibiting JAK1/STAT3 signaling. This process is achieved by regulating lipid peroxidation levels and improving mitochondrial function, suggesting a potential mechanism for restoration of the blood-spinal cord barrier (BSCB) after SCI.

Comparison of Total Laminectomy and Pedicle Screw Internal Fixation with Ultrasonic- and Microscopic-Assisted Laminectomy Replantation for Tumors of the Lumbar Spinal Canal: A Retrospective Study of 60 Cases from a Single Center.

BACKGROUND Total laminectomy with pedicle screw internal fixation is the most common surgical procedure for patients with primary tumors arising in the spinal canal, but the procedure has several limitations. This study aimed to compare total laminectomy and pedicle screw internal fixation with ultrasound- and microscope-assisted laminectomy replantation surgery in patients with tumors of the lumbar spinal canal. MATERIAL AND METHODS A retrospective study was conducted. Sixty patients with tumor spinal canal were admitted to our hospital. Patients in group A (n=32) underwent total laminectomy and pedicle screw internal fixation; patients in group B (n=28) underwent laminectomy replantation with ultrasonic and microscopic assistance. Operative time, intraoperative blood loss, operative segment, length of hospital stay, postoperative length of bed rest, and visual analog scale (VAS) score after surgery were analyzed. RESULTS Hospital stay and postoperative bed rest time of patients in group B were shorter than those in group A (P=0.004). Intraoperative blood loss, postoperative drainage volume, and postoperative pain relief of group B were significantly lower than those of group A (P=0.000). There was no significant difference in postoperative pathological results between the 2 groups (P=0.901). CONCLUSIONS Ultrasound- and microscope-assisted laminectomy replantation resulted in the reduced intraoperative blood loss, postoperative drainage volume, length of hospital stay, and postoperative VAS pain score, compared with total laminectomy and pedicle screw internal fixation for the surgical removal of tumors of the lumbar spinal canal.

The Angelman syndrome protein Ube3a is required for polarized dendrite morphogenesis in pyramidal neurons.

Pyramidal neurons have a highly polarized dendritic morphology, characterized by one long apical dendrite and multiple short basal dendrites. They function as the primary excitatory cells of the mammalian prefrontal cortex and the corticospinal tract. However, the molecular mechanisms underlying the development of polarized dendrite morphology in pyramidal neurons remain poorly understood. Here, we report that the Angelman syndrome (AS) protein ubiquitin-protein ligase E3A (Ube3a) plays an important role in specifying the polarization of pyramidal neuron dendritic arbors in mice. shRNA-mediated downregulation of Ube3a selectively inhibited apical dendrite outgrowth and resulted in impaired dendrite polarity, which could be rescued by coexpressing mouse Ube3a isoform 2, but not isoform 1 or 3. Ube3a knockdown also disrupted the polarized distribution of the Golgi apparatus, a well established cellular mechanism for asymmetric dendritic growth in pyramidal neurons. Furthermore, downregulation of Ube3a completely blocked Reelin-induced rapid deployment of Golgi into dendrite. Consistently, we also observed selective inhibition of apical dendrite outgrowth in pyramidal neurons in a mouse model of AS. Overall, these results show that Ube3a is required for the specification of the apical dendrites and dendrite polarization in pyramidal neurons, and suggest a novel pathological mechanism for AS.

CNS cell-derived exosome signatures as blood-based biomarkers of neurodegenerative diseases.

Molecular biomarkers require the reproducible capture of disease-associated changes and are ideally sensitive, specific and accessible with minimal invasiveness to patients. Exosomes are a subtype of extracellular vesicles that have gained attention as potential biomarkers. They are released by all cell types and carry molecular cargo that reflects the functional state of the cells of origin. These characteristics make them an attractive means of measuring disease-related processes within the central nervous system (CNS), as they cross the blood-brain barrier (BBB) and can be captured in peripheral blood. In this review, we discuss recent progress made toward identifying blood-based protein and RNA biomarkers of several neurodegenerative diseases from circulating, CNS cell-derived exosomes. Given the lack of standardized methodology for exosome isolation and characterization, we discuss the challenges of capturing and quantifying the molecular content of exosome populations from blood for translation to clinical use.

Tyro3 promotes the maturation of glutamatergic synapses.

The receptor tyrosine kinase Tyro3 is abundantly expressed in neurons of the neocortex, hippocampus, and striatum, but its role in these cells is unknown. We found that neuronal expression of this receptor was markedly up-regulated in the postnatal mouse neocortex immediately prior to the final development of glutamatergic synapses. In the absence of Tyro3, cortical and hippocampal synapses never completed end-stage differentiation and remained electrophysiologically and ultrastructurally immature. Tyro3-/- cortical neurons also exhibited diminished plasma membrane expression of the GluA2 subunits of AMPA-type glutamate receptors, which are essential to mature synaptic function. Correspondingly, GluA2 membrane insertion in wild-type neurons was stimulated by Gas6, a Tyro3 ligand widely expressed in the postnatal brain. Behaviorally, Tyro3-/- mice displayed learning enhancements in spatial recognition and fear-conditioning assays. Together, these results demonstrate that Tyro3 promotes the functional maturation of glutamatergic synapses by driving plasma membrane translocation of GluA2 AMPA receptor subunits.

Periodic static compression of micro-strain pattern regulates endochondral bone formation.

Introduction: Developmental engineering based on endochondral ossification has been proposed as a potential strategy for repairing of critical bone defects. Bone development is driven by growth plate-mediated endochondral ossification. Under physiological conditions, growth plate chondrocytes undergo compressive forces characterized by micro-mechanics, but the regulatory effect of micro-mechanical loading on endochondral bone formation has not been investigated. Methods: In this study, a periodic static compression (PSC) model characterized by micro-strain (with 0.5% strain) was designed to clarify the effects of biochemical/mechanical cues on endochondral bone formation. Hydrogel scaffolds loaded with bone marrow mesenchymal stem cells (BMSCs) were incubated in proliferation medium or chondrogenic medium, and PSC was performed continuously for 14 or 28 days. Subsequently, the scaffold pretreated for 28 days was implanted into rat femoral muscle pouches and femoral condylar defect sites. The chondrogenesis and bone defect repair were evaluated 4 or 10 weeks post-operation. Results: The results showed that PSC stimulation for 14 days significantly increased the number of COL II positive cells in proliferation medium. However, the chondrogenic efficiency of BMSCs was significantly improved in chondrogenic medium, with or without PSC application. The induced chondrocytes (ichondrocytes) spontaneously underwent hypertrophy and maturation, but long-term mechanical stimulation (loading for 28 days) significantly inhibited hypertrophy and mineralization in ichondrocytes. In the heterotopic ossification model, no chondrocytes were found and no significant difference in terms of mineral deposition in each group; However, 4 weeks after implantation into the femoral defect site, all scaffolds that were subjected to biochemical/mechanical cues, either solely or synergistically, showed typical chondrocytes and endochondral bone formation. In addition, simultaneous biochemical induction/mechanical loading significantly accelerated the bone regeneration. Discussion: Our findings suggest that microstrain mechanics, biochemical cues, and in vivo microenvironment synergistically regulate the differentiation fate of BMSCs. Meanwhile, this study shows the potential of micro-strain mechanics in the treatment of critical bone defects.

Applying Convolutional Neural Network to Predict Soil Erosion: A Case Study of Coastal Areas.

The development of ecological restoration projects is unsatisfactory, and soil erosion is still a problem in ecologically restored areas. Traditional soil erosion studies are mostly based on satellite remote sensing data and traditional soil erosion models, which cannot accurately characterize the soil erosion conditions in ecological restoration areas (mainly plantation forests). This paper uses high-resolution unmanned aerial vehicle (UAV) images as the base data, which could improve the accuracy of the study. Considering that traditional soil erosion models cannot accurately express the complex relationships between erosion factors, this paper applies convolutional neural network (CNN) models to identify the soil erosion intensity in ecological restoration areas, which can solve the problem of nonlinear mapping of soil erosion. In this study area, compared with the traditional method, the accuracy of soil erosion identification by applying the CNN model improved by 25.57%, which is better than baseline methods. In addition, based on research results, this paper analyses the relationship between land use type, vegetation cover, and slope and soil erosion. This study makes five recommendations for the prevention and control of soil erosion in the ecological restoration area, which provides a scientific basis and decision reference for subsequent ecological restoration decisions.

Microgroove Cues Guiding Fibrogenesis of Stem Cells via Intracellular Force.

Groove patterns are widely used in material surface modifications. However, the independent role of ditches/ridges in regulating fibrosis of soft tissues is not well-understood, especially the lack of linkage evidence in vitro and in vivo. Herein, two kinds of combinational microgroove chips with the gradient ditch/ridge width were fabricated by photolithography technology, termed R and G groups, respectively. In group R, the ridge width was 1, 5, 10, and 30 µm, with a ditch width of 30 µm; in group G, the groove width was 5, 10, 20, and 30 µm, and the ridge width was 5 µm. The effect of microgrooves on the morphology, proliferation, and expression of fibrous markers of stem cells was systematically investigated in vitro. Moreover, thicknesses of fibrous capsules were evaluated after chips were implanted into the muscular pouches of rats for 5 months. The results show that microgrooves have almost no effect on cell proliferation but significantly modulate the morphology of cells and focal adhesions (FAs) in vitro, as well as fibrosis differentiation. In particular, the differentiation of stem cells is attenuated after the intracellular force caused by stress fibers and FAs is interfered by drugs, such as rotenone and blebbistatin. Histological analysis shows that patterns of high intracellular force can apparently stimulate soft tissue fibrosis in vivo. This study not only reveals the specific rules and mechanisms of ditch/ridge regulating stem cell behaviors but also offers insight into tailoring implant surface patterns to induce controlled soft tissue fibrosis.

Dynamic base stations selection method for passive location based on GDOP.

For the problem of passive location in mobile cellular network, base stations (BSs) selection can improve positioning accuracy. Through the analysis of base station layout in cellular networks, using Geometric Dilution of Precision (GDOP) as the optimization objective, we propose a Dynamic Base Stations Selection (DBSS) method in a cellular unit. This method enables the system to dynamically select the positioning base station when positioning target in the detection area. DBSS mainly include three steps: nearest base station calculation, layout of base stations analysis, and base station selection based on the target location. We mainly focus on the derivation of four-base station dynamic selection (DBSS4) and five-base station dynamic selection (DBSS5) algorithms. In simulation experiments, DBSS4 algorithm and DBSS5algorithm were compared with the state-of-the-art of BSs selection methods. The results show that our proposed method can achieve the exhaustive search in cellular cells and reduce more than 20% of the GDOP cumulative positioning error compared with the fixed four-base station selection algorithm. Meanwhile, the proposed method is more efficient, requires less running time and floating-point operations (FLOPs) than other comparison algorithm, and is independent of localization algorithms.

Predicting Groundwater Indicator Concentration Based on Long Short-Term Memory Neural Network: A Case Study.

Prediction of groundwater quality is an essential step for sustainable utilization of water resources. Most of the related research in the study area focuses on water distribution and rational utilization of resources but lacks results on groundwater quality prediction. Therefore, this paper introduces a prediction model of groundwater quality based on a long short-term memory (LSTM) neural network. Based on groundwater monitoring data from October 2000 to October 2014, five indicators were screened as research objects: TDS, fluoride, nitrate, phosphate, and metasilicate. Considering the seasonality of water quality time series data, the LSTM neural network model was used to predict the groundwater index concentrations in the dry and rainy periods. The results suggest the model has high accuracy and can be used to predict groundwater quality. The mean absolute errors (MAEs) of these parameters are, respectively, 0.21, 0.20, 0.17, 0.17, and 0.20. The root mean square errors (RMSEs) are 0.31, 0.29, 0.28, 0.27, and 0.31, respectively. People can be given early warnings and take measures according to the forecast situation. It provides a reference for groundwater management and sustainable utilization in the study area in the future and also provides a new idea for coastal cities with similar hydrogeological conditions.

A 3D bioprinted nano-laponite hydrogel construct promotes osteogenesis by activating PI3K/AKT signaling pathway.

Development of nano-laponite as bioinks based on cell-loaded hydrogels has recently attracted significant attention for promoting bone defect repairs and regeneration. However, the underlying mechanisms of the positive function of laponite in hydrogel was not fully explored. In this study, the effect of 3D bioprinted nano-laponite hydrogel construct on bone regeneration and the potential mechanism was explored in vitro and in vivo. In vitro analyses showed that the 3D construct protected encapsulated cells from shear stresses during bioprinting, promoted cell growth and cell spreading, and BMSCs at a density of 107/mL exhibited an optimal osteogenesis potential. Osteogenic differentiation and ectopic bone formation of BMSCs encapsulated inside the 3D construct were explored by determination of calcium deposition and x-ray, micro-CT analysis, respectively. RNA sequencing revealed that activation of PI3K/AKT signaling pathway of BMSCs inside the laponite hydrogel significantly upregulated expression of osteogenic related proteins. Expression of osteogenic proteins was significantly downregulated when the PI3K/AKT pathway was inhibited. The 3D bioprinted nano-laponite hydrogel construct exhibited a superior ability for bone regeneration in rat bones with defects compared with groups without laponite as shown by micro-CT and histological examination, while the osteogenesis activity was weakened by applications of a PI3K inhibitor. In summary, the 3D bioprinted nano-laponite hydrogel construct promoted bone osteogenesis by promoting cell proliferation, differentiation through activation of the PI3K/AKT signaling pathway.

Nidogen1-enriched extracellular vesicles accelerate angiogenesis and bone regeneration by targeting Myosin-10 to regulate endothelial cell adhesion.

The technique bottleneck of repairing large bone defects with tissue engineered bone is the vascularization of tissue engineered grafts. Although some studies have shown that extracellular vesicles (EVs) derived from bone marrow mesenchymal stem cells (BMSCs) promote bone healing and repair by accelerating angiogenesis, the effector molecules and the mechanism remain unclear, which fail to provide ideas for the future research and development of cell-free interventions. Here, we found that Nidogen1-enriched EV (EV-NID1) derived from BMSCs interferes with the formation and assembly of focal adhesions (FAs) by targeting myosin-10, thereby reducing the adhesion strength of rat arterial endothelial cells (RAECs) to the extracellular matrix (ECM), and enhancing the migration and angiogenesis potential of RAECs. Moreover, by delivery with composite hydrogel, EV-NID1 is demonstrated to promote angiogenesis and bone regeneration in rat femoral defects. This study identifies the intracellular binding target of EV-NID1 and further elucidates a novel approach and mechanism, thereby providing a cell-free construction strategy with precise targets for the development of vascularized tissue engineering products.

The accuracy and learning curve of active and passive dynamic navigation-guided dental implant surgery: An in vitro study.

OBJECTIVES: Infrared dynamic navigation systems can be categorized into active and passive based on whether the surgical instruments can emit or only reflect light. This in vitro study aimed to compare the accuracy of implant placement and the learning curve of both active and passive dynamic navigation systems, using different registration methods. METHODS: Implants (n = 704) were placed in 64 sets of models and divided into active (Yizhime, DCARER, Suzhou, China) and passive (Iris-Clinic, EPED, Kaohsiung, China) dynamic navigation groups. Both marker point-based registration (M-PBR) and feature point-based registration (F-PBR) were employed for the two groups. Based on preoperative and postoperative cone-beam computed tomography imaging, the coronal, midpoint, apical, and angular deviations were analyzed from 2D and 3D views. The operation time was recorded for each group. RESULTS: The active dynamic navigation group exhibited significantly higher accuracy than the passive dynamic navigation group (angular deviation, 4.13 ± 2.39° versus 4.62 ± 3.32°; coronal global deviation, 1.48 ± 0.60 versus 1.86 ± 1.12 mm; apical global deviation, 1.75 ± 0.81 versus 2.20 ± 1.68 mm, respectively). Significant interaction effects were observed for both registration methods and four quadrants with different dynamic navigation systems. Learning curves for the two dynamic navigation groups approached each other after 12 procedures, and finally converged after 27 procedures. CONCLUSIONS: The accuracy of active dynamic navigation system was superior to that of passive dynamic navigation system. Different combinations of dynamic navigation systems, registration methods, and implanted quadrants displayed various interactions. CLINICAL SIGNIFICANCE: Our findings could provide guidance for surgeons in choosing an appropriate navigation system in various implant surgeries. Furthermore, the time required by surgeons to master the technique was calculated. Nevertheless, there are certain limitations in this in vitro study, and therefore further research is required.

CDKL5, a protein associated with rett syndrome, regulates neuronal morphogenesis via Rac1 signaling.

Mutations in cyclin-dependent kinase-like 5 (CDKL5), also known as serine/threonine kinase 9 (STK9), have been identified in patients with Rett syndrome (RTT) and X-linked infantile spasm. However, the function of CDKL5 in the brain remains unknown. Here, we report that CDKL5 is a critical regulator of neuronal morphogenesis. We identified a neuron-specific splicing variant of CDKL5 whose expression was markedly induced during postnatal development of the rat brain. Downregulating CDKL5 by RNA interference (RNAi) in cultured cortical neurons inhibited neurite growth and dendritic arborization, whereas overexpressing CDKL5 had opposite effects. Furthermore, knocking down CDKL5 in the rat brain by in utero electroporation resulted in delayed neuronal migration, and severely impaired dendritic arborization. In contrast to its proposed function in the nucleus, we found that CDKL5 regulated dendrite development through a cytoplasmic mechanism. In fibroblasts and in neurons, CDKL5 colocalized and formed a protein complex with Rac1, a critical regulator of actin remodeling and neuronal morphogenesis. Overexpression of Rac1 prevented the inhibition of dendrite growth caused by CDKL5 knockdown, and the growth-promoting effect of ectopically expressed CDKL5 on dendrites was abolished by coexpressing a dominant-negative form of Rac1. Moreover, CDKL5 was required for brain-derived neurotrophic factor (BDNF)-induced activation of Rac1. Together, these results demonstrate a critical role of CDKL5 in neuronal morphogenesis and identify a Rho GTPase signaling pathway which may contribute to CDKL5-related disorders.

[Regulation mechanism of breast cancer resistance protein by toremifene to reverse BCRP-mediated multidrug resistance in breast cancer cells].

OBJECTIVE: To explore the regulation mechanism of the reversal of breast cancer resistance protein-mediated multidrug resistance by toremifene. METHODS: Two recombinant plasmids (pcDNA3-promoter-BCRP and pcDNA3-CMV-BCRP) were designed to express the wild-type full-length BCRP cDNA enforced driven by its endogenous promoter containing a functional ERE and a CMV promoter as control, respectively. Two recombinant plasmids were transfected into ERα-positive MCF-7 and ERα-negative MDA-MB-231 breast cancer cell lines. Four kinds of BCRP expressing cell lines of MCF-7/Promoter-BCRP, MCF-7/CMV-BCRP, MDA-MB-231/Promoter-BCRP and MDA-MB-231/CMV-BCRP were established in which BCRP was promoted by the BCRP promoter and a CMV promoter as control, respectively. The drug resistant cells were treated with toremifene. Then RT-PCR, Western blot, mitoxantrone efflux assays and cytotoxicity assay were performed to detect the reversal function of BCRP by toremifene on the drug resistance cell lines. RESULTS: Toremifene significantly downregulated BCRP mRNA levels in a dose-dependent manner in ERα-positive MCF-7/Promoter-BCRP cells than that of untreated control cells. In MCF-7/Promoter-BCRP cells, toremifene at the dose of 0.1, 1 and 10 µmol/L decreased BCRP mRNA expression by 29.5% (P < 0.05), 68.1% (P < 0.01) and 97.4% (P < 0.01), respectively. After being treated with toremifene and 17ß-estradiol, the BCRP mRNA level in MCF-7/Promoter-BCRP cells was 64.2% ± 1.3%, significantly higher than that of toremifene treatment control cells (3.8% ± 0.2%,P < 0.01). Furthermore, the effect of toremifene on BCRP protein is similar in BCRP mRNA. Toremifene obviously increased the mitoxantrone fluorescence intensity and decreased the efflux activity by 47.3% (P < 0.05) in MCF-7/promoter-BCRP cells when compared with the untreated control, whereas intracellular accumulation of mitoxantrone obviously decreased and the efflux activity increased by 61.5% were observed in combination with 17ß-estradiol when compared with toremifene treatment alone. The results therefore suggested that toremifene reversed mitoxantrone resistance in MCF-7/Promoter-BCRP cells. However, in MCF-7/CMV-BCRP, MDA-MB-231/Promoter-BCRP and MDA-MB-231/CMV-BCRP cells, toremifene or in combination with 17ß-estradiol did not affect intracellular mitoxantrone uptake. CONCLUSION: Taken together, our findings indicate that expression of BCRP is downregulated by toremifene, via a novel transcriptional mechanism which might be involved in the ERE of BCRP promoter through ER-mediated to inactivate the transcription of BCRP gene.

Recent advances in critical nodes of embryo engineering technology.

The normal development and maturation of oocytes and sperm, the formation of fertilized ova, the implantation of early embryos, and the growth and development of foetuses are the biological basis of mammalian reproduction. Therefore, research on oocytes has always occupied a very important position in the life sciences and reproductive medicine fields. Various embryo engineering technologies for oocytes, early embryo formation and subsequent developmental stages and different target sites, such as gene editing, intracytoplasmic sperm injection (ICSI), preimplantation genetic diagnosis (PGD), and somatic cell nuclear transfer (SCNT) technologies, have all been established and widely used in industrialization. However, as research continues to deepen and target species become more advanced, embryo engineering technology has also been developing in a more complex and sophisticated direction. At the same time, the success rate also shows a declining trend, resulting in an extension of the research and development cycle and rising costs. By studying the existing embryo engineering technology process, we discovered three critical nodes that have the greatest impact on the development of oocytes and early embryos, namely, oocyte micromanipulation, oocyte electrical activation/reconstructed embryo electrofusion, and the in vitro culture of early embryos. This article mainly demonstrates the efforts made by researchers in the relevant technologies of these three critical nodes from an engineering perspective, analyses the shortcomings of the current technology, and proposes a plan and prospects for the development of embryo engineering technology in the future.

Multidifferentiation potential of dental-derived stem cells.

Tooth-related diseases and tooth loss are widespread and are a major public health issue. The loss of teeth can affect chewing, speech, appearance and even psychology. Therefore, the science of tooth regeneration has emerged, and attention has focused on tooth regeneration based on the principles of tooth development and stem cells combined with tissue engineering technology. As undifferentiated stem cells in normal tooth tissues, dental mesenchymal stem cells (DMSCs), which are a desirable source of autologous stem cells, play a significant role in tooth regeneration. Researchers hope to reconstruct the complete tooth tissues with normal functions and vascularization by utilizing the odontogenic differentiation potential of DMSCs. Moreover, DMSCs also have the ability to differentiate towards cells of other tissue types due to their multipotency. This review focuses on the multipotential capacity of DMSCs to differentiate into various tissues, such as bone, cartilage, tendon, vessels, neural tissues, muscle-like tissues, hepatic-like tissues, eye tissues and glands and the influence of various regulatory factors, such as non-coding RNAs, signaling pathways, inflammation, aging and exosomes, on the odontogenic/osteogenic differentiation of DMSCs in tooth regeneration. The application of DMSCs in regenerative medicine and tissue engineering will be improved if the differentiation characteristics of DMSCs can be fully utilized, and the factors that regulate their differentiation can be well controlled.

Biological sealing and integration of a fibrinogen-modified titanium alloy with soft and hard tissues in a rat model.

Percutaneous or transcutaneous devices are important and unique, and the corresponding biological sealing at the skin-implant interface is the key to their long-term success. Herein, we investigated the surface modification to enhance biological sealing, using a metal sheet and screw bonded by biomacromolecule fibrinogen mediated via pre-deposited synthetic macromolecule polydopamine (PDA) as a demonstration. We examined the effects of a Ti-6Al-4V titanium alloy modified with fibrinogen (Ti-Fg), PDA (Ti-PDA) or their combination (Ti-PDA-Fg) on the biological sealing and integration with skin and bone tissues. Human epidermal keratinocytes (HaCaT), human foreskin fibroblasts (HFF) and preosteoblasts (MC3T3-E1), which are closely related to percutaneous implants, exhibited better adhesion and spreading on all the three modified sheets compared with the unmodified alloy. After three-week subcutaneous implantation in Sprague-Dawley (SD) rats, the Ti-PDA-Fg sheets could significantly attenuate the soft tissue response and promote angiogenesis compared with other groups. Furthermore, in the model of percutaneous tibial implantation in SD rats, the Ti-PDA-Fg screws dramatically inhibited epithelial downgrowth and promoted new bone formation. Hence, the covalent immobilization of fibrinogen through the precoating of PDA is promising for enhanced biological sealing and osseointegration of metal implants with soft and hard tissues, which is critical for an orthopedic percutaneous medical device.