Fascin-1 limits myosin activity in microglia to control mechanical characterization of the injured spinal cord.

BACKGROUND: Mechanical softening of the glial scar region regulates axonal regeneration to impede neurological recovery in central nervous system (CNS) injury. Microglia, a crucial cellular component of the glial scar, facilitate neuronal survival and neurological recovery after spinal cord injury (SCI). However, the critical mechanical characterization of injured spinal cord that harmonizes neuroprotective function of microglia remains poorly understood. METHODS: Spinal cord tissue stiffness was assessed using atomic force microscopy (AFM) in a mouse model of crush injury. Pharmacological depletion of microglia using PLX5622 was used to explore the effect of microglia on mechanical characterization. Conditional knockout of Fascin-1 in microglia (Fascin-1 CKO) alone or in combination with inhibition of myosin activity was performed to delve into relevant mechanisms of microglia regulating mechanical signal. Immunofluorescence staining was performed to evaluate the related protein levels, inflammatory cells, and neuron survival after SCI. The Basso mouse scale score was calculated to assess functional recovery. RESULTS: Spinal cord tissue significantly softens after SCI. Microglia depletion or Fascin-1 knockout in microglia limits tissue softening and alters mechanical characterization, which leads to increased tissue pathology and impaired functional recovery. Mechanistically, Fascin-1 inhibits myosin activation to promote microglial migration and control mechanical characterization after SCI. CONCLUSIONS: We reveal that Fascin-1 limits myosin activity to regulate mechanical characterization after SCI, and this mechanical signal should be considered in future approaches for the treatment of CNS diseases.

Integrated genetic analysis of diabetic complications: Bioinformatics insights into foot ulcers, neuropathy and peripheral artery disease.

Diabetic foot ulcers (DFU), diabetic peripheral neuropathy (DPN) and peripheral arterial disease (PAD) are common complications of diabetes mellitus, while diabetic peripheral neuropathy and peripheral arterial disease contribute to the pathogenesis of diabetic foot ulcers, and the pathogenic mechanisms between these three diseases still need further investigation. The keywords 'diabetic foot ulcer', 'diabetic peripheral neuropathy' and 'atherosclerosis' were used to search for related gene sets in the GEO database. Differentially expressed genes (DEGs) were screened and analysed for GO, KEGG and enrichR functional enrichment. Potential three disease biomarkers were identified by SVM-SVM-RFE and LASSO regression analysis. The results were also validated using external datasets and discriminability was measured by area under the ROC curve (AUC). Finally, biomarkers and co-upregulated genes were analysed through the GSEA and Attie Laboratories diabetes databases. A total of 11 shared genes (KRT16, CD24, SAMD9L, SRGAP2, FGL2, GPR34, DDIT4, NFE2L3, FBLN5, ANXA3 and CPA3), two biomarkers (SAMD9L and FGL2) and one co-upregulated gene (CD24) were screened. GO and KEGG pathway analysis of DEGs, enrichr enrichment analysis of shared differential genes and GSEA analysis of biomarkers showed that these significant genes were mainly focused on vasoregulatory, inflammatory-oxidative stress and immunomodulatory pathways. In this study, we used bioinformatics to investigate the intrinsic relationship and potential mechanisms of three common lower extremity complications of diabetes and identified two pivotal genes using the LASSO model and the SVM-RFE algorithm, which will further help clinicians to understand the relationship between diabetic complications, improve the diagnosis and treatment of diabetic foot problems and help doctors to identify the potential risk factors of diabetic foot.

Myelin Debris Impairs Tight Junctions and Promotes the Migration of Microvascular Endothelial Cells in the Injured Spinal Cord.

Clearance of myelin debris caused by acute demyelination is an essential process for functional restoration following spinal cord injury (SCI). Microvascular endothelial cells, acting as "amateur" phagocytes, have been confirmed to engulf and degrade myelin debris, promoting the inflammatory response, robust angiogenesis, and persistent fibrosis. However, the effect of myelin debris engulfment on the function of endothelial tight junctions (TJs) remains unclear. Here, we demonstrate that myelin debris uptake impairs TJs and gap junctions of endothelial cells in the lesion core of the injured spinal cord and in vitro, resulting in increased permeability and leakage. We further show that myelin debris acts as an inducer to regulate the endothelial-to-mesenchymal transition in a dose-dependent manner and promotes endothelial cell migration through the PI3K/AKT and ERK signaling pathways. Together, our results indicate that myelin debris engulfment impairs TJs and promotes the migration of endothelial cells. Accelerating myelin debris clearance may help maintain blood-spinal cord barrier integrity, thus facilitating restoration of motor and sensory function following SCI.

SU16f inhibits fibrotic scar formation and facilitates axon regeneration and locomotor function recovery after spinal cord injury by blocking the PDGFRß pathway.

BACKGROUND: Excessively deposited fibrotic scar after spinal cord injury (SCI) inhibits axon regeneration. It has been reported that platelet-derived growth factor receptor beta (PDGFRß), as a marker of fibrotic scar-forming fibroblasts, can only be activated by platelet-derived growth factor (PDGF) B or PDGFD. However, whether the activation of the PDGFRß pathway can mediate fibrotic scar formation after SCI remains unclear. METHODS: A spinal cord compression injury mouse model was used. In situ injection of exogenous PDGFB or PDGFD in the spinal cord was used to specifically activate the PDGFRß pathway in the uninjured spinal cord, while intrathecal injection of SU16f was used to specifically block the PDGFRß pathway in the uninjured or injured spinal cord. Immunofluorescence staining was performed to explore the distributions and cell sources of PDGFB and PDGFD, and to evaluate astrocytic scar, fibrotic scar, inflammatory cells and axon regeneration after SCI. Basso Mouse Scale (BMS) and footprint analysis were performed to evaluate locomotor function recovery after SCI. RESULTS: We found that the expression of PDGFD and PDGFB increased successively after SCI, and PDGFB was mainly secreted by astrocytes, while PDGFD was mainly secreted by macrophages/microglia and fibroblasts. In addition, in situ injection of exogenous PDGFB or PDGFD can lead to fibrosis in the uninjured spinal cord, while this profibrotic effect could be specifically blocked by the PDGFRß inhibitor SU16f. We then treated the mice after SCI with SU16f and found the reduction of fibrotic scar, the interruption of scar boundary and the inhibition of lesion and inflammation, which promoted axon regeneration and locomotor function recovery after SCI. CONCLUSIONS: Our study demonstrates that activation of PDGFRß pathway can directly induce fibrotic scar formation, and specific blocking of this pathway would contribute to the treatment of SCI.

Gankyrin activates the hedgehog signalling to drive metastasis in osteosarcoma.

Gankyrin is a regulatory subunit of the 26-kD proteasome complex and promotes the occurrence and progression of many malignancies. However, the role of gankyrin in osteosarcoma (OS) metastasis remains unclear. Hedgehog signalling has been shown to regulate stem cell homeostasis and cancer metastasis, but the mechanisms that activate this pathway in OS are still poorly understood. Here, a series of in vitro and in vivo assays were carried out to explore the function and mechanism of gankyrin regulating Hedgehog signalling in OS. We demonstrated that gankyrin promotes migration, invasion and regulates the expression of some stemness factors by up-regulating Gli1 in OS. Importantly, our data showed an interaction between gankyrin and Gli1. Moreover, gankyrin suppresses the ubiquitin-mediated degradation of Gli1 protein in OS. Gankyrin also significantly promotes the lung metastasis of OS in vivo. Our findings suggest that gankyrin drives metastasis and regulates the expression of some stemness factors in osteosarcoma by activating Hedgehog signalling, indicating that drug screening for compounds targeting gankyrin may contribute to the development of novel and effective therapies for OS.

Copper(II)-Catalyzed Direct C-H (Hetero)arylation at the C3 Position of Indoles Assisted by a Removable N,N-Bidentate Auxiliary Moiety.

The regioselective arylation of inert C3-H bonds in indoles reacting with arylboronates via effective copper-mediated catalysis with the aid of a facile and removable 2-pyridinylisopropyl (PIP) group without ligand participation is reported. This newly established method features high compatibility with diverse functional groups between coupling partners, including both indole substrates and arylboron reagents, consequentially leading to operational simplicity and providing access to generate the desired arylated products in good to excellent yields of up to 97%. Synthetically, the PIP-derived amide moiety could subsequently be readily removed under mild reaction conditions to produce useful indole carboxylic acids for further transformation.

Synthesis of indolo[2,1-α]isoquinoline derivatives via metal-free radical cascade cyclization.

In the present studies, we describe a convenient and efficient protocol for the synthesis of the indolo[2,1-α]isoquinoline core structure through the reaction of 2-aryl-N-acryloyl indoles and aryl or alkyl α-keto acids under air environment in four hours. The developed approach features broad substrate scope and good functional group tolerance under mild reaction conditions without a metal catalyst participation. A series of valuable indolo[2,1-α] isoquinoline derivatives bearing various functional groups were synthesized using this method in good to excellent yields. Based on a series of control experiments, a radical pathway was proposed to explain the experiment.

Copper(II)-catalysed direct C3-H esterification of indoles assisted by an N,N-bidentate auxiliary moiety.

The regioselective direct C3-esterification of indoles with OXA is developed in an efficient reaction with carboxylic acids using the catalyst CuBr2 and oxidants Ag2CO3 and K2S2O8. The simple experimental procedure is proved to be broadly applicable to a range of substrates, including aromatic and aliphatic acids, and the corresponding products were obtained in good yields up to 87%. At the same time, it provides a valuable approach to produce C3-benzyl derivatives of indoles through reaction with benzyl carboxylic acid under the same reaction conditions.

Immunomodulatory Activity of Low Molecular-Weight Peptides from Nibea japonica in RAW264.7 Cells via NF-κB Pathway.

In this study, a low molecular-weight (Mw) peptide named NJP (<1 kDa), was purified from a protein hydrolysate of Nibea japonica by ultrafiltration, and its immunomodulatory effect on RAW264.7 cells was evaluated. The lactate dehydrogenase (LDH) and MTT assays were performed to explore the cytotoxicity of NJP. The results showed that NJP promoted cell proliferation and had no significant toxic effects on RAW264.7 cells. Moreover, the cells formed multiple pseudopodia indicating that they were in activated state. Further tests showed that NJP significantly promoted phagocytic capacity, and the secretion of proinflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1ß (IL-1ß). It also increased the synthesis of nitric oxide (NO) by upregulating inducible nitric oxide synthase (iNOS) protein level. Flow cytometry revealed that NJP promoted cell cycle progression and increased the percentage of cells in G0/G1 phase. NJP promoted IκBα degradation, p65 and nuclear factor (NF)-κB activation and translocation by up-regulating IKKα/ß protein expression. In conclusion, these results indicated that NJP exerts immunomodulatory effects on RAW264.7 cells through the NF-κB signaling pathway. Therefore, NJP can be incorporated in the production of functional foods or nutraceuticals.

Physicochemical Properties and Biocompatibility Evaluation of Collagen from the Skin of Giant Croaker (Nibea japonica).

Collagen and collagen peptides are widely used as cosmetic ingredients. In the present study, acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from giant croaker (Nibea japonica) skin. The proline hydroxylation rates of ASC and PSC were 38.1% and 39.3%. The denaturation temperatures (Td) were approximately 34.5 °C for both ASC and PSC. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fourier transform infrared spetroscopy (FTIR) demonstrated that ASC and PSC were mainly type I collagen. Furthermore, As, Pb and Hg contents in the extracted collagen were lower than the national standards of China. In addition, collagen had good moisture absorption and retention properties when compared to glycerol. The collagen was also not cytotoxic to NIH-3T3 fibroblast cells, indicating that Nibea japonica skin collagen can be utilized in cosmetic applications.

Temperature-controlled transparent-film heater based on silver nanowire-PMMA composite film.

We fabricated a high-performance film heater based on a silver nanowire and polymethyl methacrylate (Ag NW-PMMA) composite film, which was synthesized with the assistance of mechanical lamination and an in situ transfer method. The films exhibit excellent conductivity, high figure of merit, and strong adhesion of percolation network to substrate. By controlling NW density, we prepared the films with a transmittance of 44.9-85.0% at 550 nm and a sheet resistance of 0.13-1.40 Ω sq-1. A stable temperature ranging from 130 °C-40 °C was generated at 3.0 V within 10-30 s, indicating that the resulting film heaters show a rapid thermal response, low driving voltage and stable temperature recoverability. Furthermore, we demonstrated the applications of the film heater in defrosting and a physical therapeutic instrument. A fast defrosting on the composite film with a transmittance of 88% was observed by applying a 9 V driving voltage for 20 s. Meanwhile, we developed a physical therapeutic instrument with two modes of thermotherapy and electronic-pulse massage by using the composite films as two electrodes, greatly decreasing the weight and power consumption compared to a traditional instrument. Therefore, Ag NW-PMMA film can be a promising candidate for diversified heating applications.

MoS2@MWCNTs with Rich Vacancy Defects for Effective Piezocatalytic Degradation of Norfloxacin via Innergenerated-H2O2: Enhanced Nonradical Pathway and Synergistic Mechanism with Radical Pathway.

Molybdenum disulfide (MoS2)-based materials for piezocatalysis are unsatisfactory due to their low actual piezoelectric coefficient and poor electrical conductivity. Herein, 1T/3R phase MoS2 grown in situ on multiwalled carbon nanotubes (MWCNTs) was proposed. MoS2@MWCNTs exhibited the interwoven morphology of thin nanoflowers and tubes, and the piezoelectric response of MoS2@MWCNTs was 4.07 times higher than that of MoS2 via piezoresponse force microscopy (PFM) characterization. MoS2@MWCNTs exhibited superior activity with a 91% degradation rate of norfloxacin (NOR) after actually working 24 min (as for rhodamine B, reached 100% within 18 min) by pulse-mode ultrasonic vibration-triggered piezocatalysis. It was found that piezocatalysis for removing pollutants was attributed to the synergistic effect of free radicals (•OH and O2•-) and nonfree radical (1O2, key role) pathways, together with the innergenerated-H2O2 promoting the degradation rate. 1O2 can be generated by electron transfer and energy transfer pathways. The presence of oxygen vacancies (OVs) induced the transformation of O2 to 1O2 by triplet energy transfer. The fast charge transfer in MoS2@MWCNTs heterostructure and the coexistence of sulfur vacancies and OVs enhanced charge carrier separation resulting in a prominent piezoelectric effect. This work opens up new avenues for the development of efficient piezocatalysts that can be utilized for environmental purification.

Pigment epithelium­derived factor inhibits proliferation, invasion and angiogenesis, and induces ferroptosis of extravillous trophoblasts by targeting Wnt­ß­catenin/VEGF signaling in placenta accreta spectrum.

Placenta accreta spectrum (PAS) is one of the most dangerous complications in obstetrics, which can lead to severe postpartum bleeding and shock, and even necessitate uterine removal. The abnormal migration and invasion of extravillous trophoblast cells (EVTs) and enhanced neovascularization occurring in an uncontrolled manner in time and space are closely related to the abnormal expression of pro­angiogenic and anti­angiogenic factors. The pigment epithelium­derived factor (PEDF) is a multifunctional regulatory factor that participates in several important biological processes and is recognized as the most efficient inhibitor of angiogenesis. The present study aimed to explore the effects of PEDF on EVT phenotypes and the underlying mechanisms in PAS. HTR­8/SVneo cells were transfected to overexpress or knock down PEDF. Cell proliferation and invasion were assessed using Cell Counting Kit­8, 5­ethynyl­2'­deoxyuridine and Transwell assays. In vitro angiogenesis was analyzed using tube formation assays. The degree of ferroptosis was assessed by evaluating the levels of lipid reactive oxygen species, total iron, Fe2+, malondialdehyde and reduced glutathione using commercial kits. The expression levels of biomarkers of ferroptosis, angiogenesis, cell proliferation and Wnt signaling were examined by western blotting. PEDF overexpression decreased the proliferation, invasion and angiogenesis, and induced ferroptosis of EVTs. Activation of Wnt signaling with BML­284 and overexpression of vascular endothelial growth factor (VEGF) reversed the PEDF overexpression­induced suppression of cell proliferation, invasion and tube formation. PEDF overexpression­induced ferroptosis was also decreased by Wnt agonist treatment and VEGF overexpression. It was predicted that PEDF suppressed the proliferation, invasion and angiogenesis, and increased ferroptosis in EVTs by decreasing Wnt­ß­catenin/VEGF signaling. The findings of the present study suggested a novel regulatory mechanism of the phenotypes of EVTs and PAS.

DropLab: an automated magnetic digital microfluidic platform for sample-to-answer point-of-care testing-development and application to quantitative immunodiagnostics.

In point-of-care testing (POCT), tests are performed near patients and results are given rapidly for timely clinical decisions. Immunodiagnostic assays are one of the most important analyses for detecting and quantifying protein-based biomarkers. However, existing POCT immunodiagnostics mainly rely on the lateral flow assay (LFA), which has limited sensitivity or quantification capability. Although other immunodiagnostic assays, such as enzyme-linked immunosorbent assays (ELISAs), offer more sensitive and quantitative results, they require complex liquid manipulations that are difficult to implement in POCT settings by conventional means. Here, we show the development of DropLab, an automated sample-in-answer-out POCT immunodiagnostic platform based on magnetic digital microfluidic (MDM) technology. DropLab performs microbead-based ELISA in droplets to offer more sensitive and quantitative testing results. The intricate liquid manipulations required for ELISA are accomplished by controlling droplets with magnetic microbeads using MDM technology, which enables us to achieve full automation and easy operations with DropLab. Four ELISAs (the sample in triplicates and a negative control) can be run in parallel on the thermoformed disposable chip, which greatly improves the throughput and accuracy compared to those of other POCT immunodiagnostic devices. DropLab was validated by measuring two protein targets and one antibody target. The testing results showed that the limit of detection (LOD) of DropLab matched that of the conventional ELISA in a microwell plate. DropLab brings MDM one step closer to being a viable medical technology that is ready for real-world POCT applications.

Molecular Dynamics Simulation on Nanoindentation of M50 Bearing Steel.

M50 bearing steel has great potential for applications in the field of aerospace engineering, as it exhibits outstanding mechanical and physical properties. From a microscopic point of view, bearing wear originates from the microscopic region of the contact interface, which usually only contains hundreds or even several atomic layers. However, the existing researches seldom study the wear of M50 bearing steel on the microscopic scale. This study explored the atomic-scale modeling method of M50 bearing steel. Then molecular dynamics simulations of nanoindentation on the M50 bearing steel model were carried out to study the size effect of the mechanical behaviors. The simulation results show that with the change in the radius of the diamond indenter in the nanoindentation simulation, the calculated nanohardness decreases. According to the size effect, when the indentation radius is 200 nm, the hardness obtained by the simulation is about 9.26 GPa, and that of the M50 sample measured by the nanoindentation is 10.4 GPa. Then nanoindentation simulations were carried out at different temperatures. The main bearings of aero-engines generally work at 300-500 degrees Celsius. When the simulated temperature was increased from 300 K to 800 K, the hardness of the model decreased by 15%, and the model was more prone to plastic deformation. In this study, a new molecular dynamics modeling method for M50 bearing steel was proposed, and then nanoindentation simulation was carried out, and the nanoindentation experiment verified the correctness of the model. These results are beneficial to the basic understanding of the mechanical performance of M50 bearing steel.

Prognostic value of inflammatory markers for in-hospital mortality in intensive care patients with acute ischemic stroke: a retrospective observational study based on MIMIC-IV.

Background: Acute ischemic stroke (AIS) is a primary cause of death and disability worldwide. Four markers that can be readily determined from peripheral blood, namely, the systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and total bilirubin, were measured in this study. We examined the relationship between the SII and in-hospital mortality after AIS and evaluated which of the above four indicators was most accurate for predicting in-hospital mortality after AIS. Methods: We selected patients from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database who were aged >18 years and who were diagnosed with AIS on admission. We collected the patients' baseline characteristics, including various clinical and laboratory data. To investigate the relationship between the SII and in-hospital mortality in patients with AIS, we employed the generalized additive model (GAM). Differences in in-hospital mortality between the groups were summarized by the Kaplan-Meier survival analysis and the log-rank test. The receiver operating characteristic (ROC) curve analysis was used to assess the accuracy of the four indicators (SII, NLR, PLR, and total bilirubin) for predicting in-hospital mortality in patients with AIS. Results: The study included 463 patients, and the in-hospital mortality rate was 12.31%. The GAM analysis showed a positive correlation between the SII and in-hospital mortality in patients with AIS, but the correlation was not linear. Unadjusted Cox regression identified a link between a high SII and an increased probability of in-hospital mortality. We also found that patients with an SII of >1,232 (Q2 group) had a considerably higher chance of in-hospital mortality than those with a low SII (Q1 group). The Kaplan-Meier analysis demonstrated that patients with an elevated SII had a significantly lower chance of surviving their hospital stay than those with a low SII. According to the results of the ROC curve analysis, the in-hospital mortality of patients with AIS predicted by the SII had an area under the ROC curve of 0.65, which revealed that the SII had a better discriminative ability than the NLR, PLR, and total bilirubin. Conclusion: The in-hospital mortality of patients with AIS and the SII were positively correlated, but not linearly. A high SII was associated with a worse prognosis in patients with AIS. The SII had a modest level of discrimination for forecasting in-hospital mortality. The SII was slightly better than the NLR and significantly better than the PLR and total bilirubin for predicting in-hospital mortality in patients with AIS.

DropCarba - An automated magnetic digital microfluidic platform for rapid phenotypic testing of carbapenemase-producing Gram-negative bacilli.

Carbapenemase-producing Gram-negative bacilli (CPGNB) is a type of antibiotic-resistant pathogens that often lead to severe clinical consequences. Phenotypic tests, such as Carba NP and blue Carba, are able to detect the resistant mechanism and provide rapid detection of carbapenemase producers to potentially guide personalized therapy. However, these tests require relatively tedious hands-on fluidic operations, and the assay format is ill-suited for automation and parallelization for improved throughput. In this study, we report an automated magnetic digital microfluidics-based platform, known as DropCarba, for parallel CPGNB detection in droplets. It automates the entire carbapenemase testing process and eliminates the need for almost all hands-on fluidic operations, which ensures high consistency and minimizes human errors with a simple "press-and-go" operation. DropCarba was validated with a large number of bacterial isolates of various Enterobacterales species (200 strains in total with 100 CPGNB and 100 non-resistant strains) in a blinded manner, and the results agree well with the benchmark Carba NP. DropCarba, with its full automation, simple operation, reduced reagent consumption, parallelization processing, and scalable manufacturing, will greatly improve CPGNB screening and make a valuable contribution to our fight against antibiotic resistance.

Image-based real-time feedback control of magnetic digital microfluidics by artificial intelligence-empowered rapid object detector for automated in vitro diagnostics.

In vitro diagnostics (IVD) plays a critical role in healthcare and public health management. Magnetic digital microfluidics (MDM) perform IVD assays by manipulating droplets on an open substrate with magnetic particles. Automated IVD based on MDM could reduce the risk of accidental exposure to contagious pathogens among healthcare workers. However, it remains challenging to create a fully automated IVD platform based on the MDM technology because of a lack of effective feedback control system to ensure the successful execution of various droplet operations required for IVD. In this work, an artificial intelligence (AI)-empowered MDM platform with image-based real-time feedback control is presented. The AI is trained to recognize droplets and magnetic particles, measure their size, and determine their location and relationship in real time; it shows the ability to rectify failed droplet operations based on the feedback information, a function that is unattainable by conventional MDM platforms, thereby ensuring that the entire IVD process is not interrupted due to the failure of liquid handling. We demonstrate fundamental droplet operations, which include droplet transport, particle extraction, droplet merging and droplet mixing, on the MDM platform and show how the AI rectify failed droplet operations by acting upon the feedback information. Protein quantification and antibiotic resistance detection are performed on this AI-empowered MDM platform, and the results obtained agree well with the benchmarks. We envision that this AI-based feedback approach will be widely adopted not only by MDM but also by other types of digital microfluidic platforms to offer precise and error-free droplet operations for a wide range of automated IVD applications.

Fingolimod (FTY720) Hinders Interferon-γ-Mediated Fibrotic Scar Formation and Facilitates Neurological Recovery After Spinal Cord Injury.

Following spinal cord injury (SCI), fibrotic scar inhibits axon regeneration and impairs neurological function recovery. It has been reported that T cell-derived interferon (IFN)-γ plays a pivotal role in promoting fibrotic scarring in neurodegenerative disease. However, the role of IFN-γ in fibrotic scar formation after SCI has not been declared. In this study, a spinal cord crush injury mouse was established. Western blot and immunofluorescence showed that IFN-γ was surrounded by fibroblasts at 3, 7, 14, and 28 days post-injury. Moreover, IFN-γ is mainly secreted by T cells after SCI. Further, in situ injection of IFN-γ into the normal spinal cord resulted in fibrotic scar formation and inflammation response at 7 days post-injection. After SCI, the intraperitoneal injection of fingolimod (FTY720), a sphingosine-1-phosphate receptor 1 (S1PR1) modulator and W146, an S1PR1 antagonist, significantly reduced T cell infiltration, attenuating fibrotic scarring via inhibiting IFN-γ/IFN-γR pathway, while in situ injection of IFN-γ diminished the effect of FTY720 on reducing fibrotic scarring. FTY720 treatment inhibited inflammation, decreased lesion size, and promoted neuroprotection and neurological recovery after SCI. These findings demonstrate that the inhibition of T cell-derived IFN-γ by FTY720 suppressed fibrotic scarring and contributed to neurological recovery after SCI.

Titanium dioxide nanotubes increase purinergic receptor P2Y6 expression and activate its downstream PKCα-ERK1/2 pathway in bone marrow mesenchymal stem cells under osteogenic induction.

Titanium dioxide (TiO2) nanotubes can improve the osseointegration of pure titanium implants, but this exact mechanism has not been fully elucidated. The purinergic receptor P2Y6 is expressed in bone marrow mesenchymal stem cells (BMSCs) and participates in the regulation of bone metabolism. However, it is unclear as to whether P2Y6 is involved in the osteogenic differentiation of BMSCs induced by TiO2 nanotubes. TiO2 nanotubes were prepared on the surface of titanium specimens using the anodizing method and characterized their features. Quantitative reverse transcriptase polymerase chain reaction and western blotting were used to detect the expression of P2Y6, markers of osteogenic differentiation, and PKCα-ERK1/2. A rat femoral defect model was established to evaluate the osseointegration effect of TiO2 nanotubes combined with P2Y6 agonists. The results showed that the average inner diameter of the TiO2 nanotubes increased with an increase in voltage (voltage range of 30-90V), and the expression of P2Y6 in BMSCs could be upregulated by TiO2 nanotubes in osteogenic culture. Inhibition of P2Y6 expression partially inhibited the osteogenic effect of TiO2 nanotubes and downregulated the activity of the PKCα-ERK1/2 pathway. When using in vitro and in vivo experiments, the osteogenic effect of TiO2 nanotubes when combined with P2Y6 agonists was more pronounced. TiO2 nanotubes promoted the P2Y6 expression of BMSCs during osteogenic differentiation and promoted osteogenesis by activating the PKCα-ERK1/2 pathway. The combined application of TiO2 nanotubes and P2Y6 agonists may be an effective new strategy to improve the osseointegration of titanium implants. STATEMENT OF SIGNIFICANCE: Titanium dioxide (TiO2) nanotubes can improve the osseointegration of pure titanium implants, but this exact mechanism has not been fully elucidated. The purinergic receptor P2Y6 is expressed in bone marrow mesenchymal stem cells (BMSCs) and participates in the regulation of bone metabolism. However, it is unclear as to whether P2Y6 is involved in the osteogenic differentiation of BMSCs induced by TiO2 nanotubes. For the first time, this study revealed the relationship between TiO2 nanotubes and purine receptor P2Y6, and further explored its mode of action, which may provide clues as to the regulatory role of TiO2 nanotubes on osteogenic differentiation of BMSCs. These findings will help to develop novel methods for guiding material design and biosafety evaluation of nano implants.