Targeting foamy macrophages by manipulating ABCA1 expression to facilitate lesion healing in the injured spinal cord.

Spinal cord injury (SCI) triggers a complex cascade of events, including myelin loss, neuronal damage, neuroinflammation, and the accumulation of damaged cells and debris at the injury site. Infiltrating bone marrow derived macrophages (BMDMϕ) migrate to the epicenter of the SCI lesion, where they engulf cell debris including abundant myelin debris to become pro-inflammatory foamy macrophages (foamy Mϕ), participate neuroinflammation, and facilitate the progression of SCI. This study aimed to elucidate the cellular and molecular mechanisms underlying the functional changes in foamy Mϕ and their potential implications for SCI. Contusion at T10 level of the spinal cord was induced using a New York University (NYU) impactor (5 g rod from a height of 6.25 mm) in male mice. ABCA1, an ATP-binding cassette transporter expressed by Mϕ, plays a crucial role in lipid efflux from foamy cells. We observed that foamy Mϕ lacking ABCA1 exhibited increased lipid accumulation and a higher presence of lipid-accumulated foamy Mϕ as well as elevated pro-inflammatory response in vitro and in injured spinal cord. We also found that both genetic and pharmacological enhancement of ABCA1 expression accelerated lipid efflux from foamy Mϕ, reduced lipid accumulation and inhibited the pro-inflammatory response of foamy Mϕ, and accelerated clearance of cell debris and necrotic cells, which resulted in functional recovery. Our study highlights the importance of understanding the pathologic role of foamy Mϕ in SCI progression and the potential of ABCA1 as a therapeutic target for modulating the inflammatory response, promoting lipid metabolism, and facilitating functional recovery in SCI.

Distributed Consensus Estimation for Networked Multi-Sensor Systems under Hybrid Attacks and Missing Measurements.

Cyber-security research on networked multi-sensor systems is crucial due to the vulnerability to various types of cyberattacks. For the development of effective defense measures, attention is required to gain insight into the complex characteristics and behaviors of cyber attacks from the attacker's perspective. This paper aims to tackle the problem of distributed consensus estimation for networked multi-sensor systems subject to hybrid attacks and missing measurements. To account for both random denial of service (DoS) attacks and false data injection (FDI) attacks, a hybrid attack model on the estimator-to-estimator communication channel is presented. The characteristics of missing measurements are defined by random variables that satisfy the Bernoulli distribution. Then a modified consensus-based distributed estimator, integrated with the characteristics of hybrid attacks and missing measurements, is presented. For reducing the computational complexity of the optimal distributed estimation method, a scalable suboptimal distributed consensus estimator is designed. Sufficient conditions are further provided for guaranteeing the stability of the proposed suboptimal distributed estimator. Finally, a simulation experiment on aircraft tracking is executed to validate the effectiveness and feasibility of the proposed algorithm.

FKBP10 promotes proliferation of glioma cells via activating AKT-CREB-PCNA axis.

BACKGROUND: Although the availability of therapeutic options including temozolomide, radiotherapy and some target agents following neurosurgery, the prognosis of glioma patients remains poor. Thus, there is an urgent need to explore possible targets for clinical treatment of this disease. METHODS: Tissue microarrays and immunohistochemistry were used to detect FKBP10, Hsp47, p-AKT (Ser473), p-CREB (Ser133) and PCNA expression in glioma tissues and xenografts. CCK-8 tests, colony formation assays and xenograft model were performed to test proliferation ability of FKBP10 in glioma cells in vitro and in vivo. Quantitative reverse transcriptase-PCR, western-blotting, GST-pull down, co-immunoprecipitation and confocal-immunofluorescence staining assay were used to explore the molecular mechanism underlying the functions of overexpressed FKBP10 in glioma cells. RESULTS: FKBP10 was highly expressed in glioma tissues and its expression was positively correlates with grade, poor prognosis. FKBP10-knockdown suppressed glioma cell proliferation in vitro and subcutaneous/orthotopic xenograft tumor growth in vivo. Silencing of FKBP10 reduced p-AKT (Ser473), p-CREB (Ser133), PCNA mRNA and PCNA protein expression in glioma cells. FKBP10 interacting with Hsp47 enhanced the proliferation ability of glioma cells via AKT-CREB-PCNA cascade. In addition, correlation between these molecules were also found in xenograft tumor and glioma tissues. CONCLUSIONS: We showed for the first time that FKBP10 is overexpressed in glioma and involved in proliferation of glioma cells by interacting with Hsp47 and activating AKT-CREB-PCNA signaling pathways. Our findings suggest that inhibition of FKBP10 related signaling might offer a potential therapeutic option for glioma patients.

Remarkable inhibition effects of afatinib alone or combining with paclitaxel in esophageal squamous cell carcinoma.

BACKGROUND AND AIM: Chemotherapy drugs do not work well in esophageal squamous cell carcinoma (ESCC), and none of the targeted drugs have been applied in clinic. This study aims to identify effective targeted drugs and related biomarkers for the treatment of ESCC. METHODS: The effect of 40 Food and Drug Administration-approved small-molecule inhibitors was first tested in five ESCC cell lines. CCK8 assays and xenografts derived from ESCC cell lines were performed to evaluate the anti-ESCC effects of inhibitors or chemotherapeutic agents in vitro and in vivo, respectively. Immunohistochemistry was utilized to analyze the p-EGFR expression in tissues. Western blot combining with gray analysis was conducted to detect the expression of interest protein. Flow cytometry and immunofluorescence assay were used to analyze apoptosis, cell cycle, and mitotic changes after drug treatment. RESULTS: Afatinib showed remarkable effects on inhibiting ESCC cells with higher expression of p-EGFR. Results from combinatorial screening in ESCC cells expressing lower phosphorylation level of EGFR showed that paclitaxel and afatinib presented a significant synergistic inhibitory effect (P < 0.001). Molecular analysis revealed that paclitaxel sensitized afatinib by activating EGFR, and afatinib in combination with paclitaxel effectively blocked MAPK pathway and induced G2/M cell arrest and apoptosis that is an indicator of mitotic catastrophe. CONCLUSIONS: Our data demonstrate that afatinib is an effective drug for patients with ESCC expressing higher phosphorylation level of EGFR. And for patients with lower p-EGFR in tumors, paclitaxel in combination with afatinib might be a promising therapeutic strategy in ESCC.

PEBP4 promoted the growth and migration of cancer cells in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most common malignancies in the world. Numerous studies have linked the activation of AKT to the progression of PDAC. Phosphatidylethanolamine-binding protein 4 (PEBP4) has been reported to be upregulated in various cancer types. However, its expression pattern and biological functions in PDAC are unknown. In this study, it was found that the messenger RNA (mRNA) and protein level of PEBP4 was elevated in PDAC samples. Forced expression of PEBP4 in PDAC cell lines promoted cell growth and migration, while downregulation of PEBP4 in PDAC cells by RNA interference (RNAi) inhibited the growth, migration, and metastasis of the cancer cells. PEBP4 interacted with AKT and promoted the phosphorylation of serine 473 in AKT. Collectively, this study suggested that PEBP4 might promote the progression of PDAC through activating AKT signaling and PEBP4 might be a promising therapeutic target for PDAC treatment.

KLF2 is downregulated in pancreatic ductal adenocarcinoma and inhibits the growth and migration of cancer cells.

Members of the Kruppel-like factor (KLF) family have been considered as the tumor suppressors for their inhibitory effects on cell proliferation. Dysregulation of KLF2, a member of KLF family, has been observed in various cancer types. However, its expression pattern and functions in the pancreatic ductal adenocarcinoma (PDAC) are unknown. In this study, we examined the expression of KLF2 in PDAC clinical samples and evaluated the functions of KLF2 in the progression of PDAC. KLF2 is shown to be downregulated in PDAC clinical samples and overexpression of KLF2 inhibits the growth, migration, and metastasis of PDAC cancer cells. KLF2 interacts with beta-catenin and negatively regulates the beta-catenin/TCF signaling. Taken together, this study suggests the suppressive functions of KLF2 in PDAC.

Catalase-Laden Microdevices for Cell-Mediated Enzyme Delivery.

Enzymes have been used to treat various human diseases and traumas. However, the therapeutic utility of free enzymes is impeded by their short circulation time, lack of targeting ability, immunogenicity, and inability to cross biological barriers. Cell-mediated drug delivery approach offers the unique capability to overcome these limitations, but the traditional cell-mediated enzyme delivery techniques suffer from drawbacks such as risk of intracellular degradation of and low loading capacity for the payload enzyme. This article presents the development of a novel cell-mediated enzyme delivery technique featuring the use of micrometer-sized disk-shaped particles termed microdevices. The microdevices are fabricated by layer-by-layer assembly and soft lithography with catalase being used as a model therapeutic enzyme. The amount of catalase in the microdevices can be controlled with the number of catalase layers. Catalase in the microdevices is catalytically active, and active catalase is slowly released from the microdevices. Moreover, cell-microdevice complexes are produced by attaching the catalase-laden microdevices to the external surface of both K562 cells and mouse embryonic stem cells. This technique is potentially applicable to other enzymes and cells and promises to be clinically useful.

Anti-Inflammatory Mechanism of Neural Stem Cell Transplantation in Spinal Cord Injury.

Neural stem cell (NSC) transplantation has been proposed to promote functional recovery after spinal cord injury. However, a detailed understanding of the mechanisms of how NSCs exert their therapeutic plasticity is lacking. We transplanted mouse NSCs into the injured spinal cord seven days after SCI, and the Basso Mouse Scale (BMS) score was performed to assess locomotor function. The anti-inflammatory effects of NSC transplantation was analyzed by immunofluorescence staining of neutrophil and macrophages and the detection of mRNA levels of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and interleukin-12 (IL-12). Furthermore, bone marrow-derived macrophages (BMDMs) were co-cultured with NSCs and followed by analyzing the mRNA levels of inducible nitric oxide synthase (iNOS), TNF-α, IL-1ß, IL-6 and IL-10 with quantitative real-time PCR. The production of TNF-α and IL-1ß by BMDMs was examined using the enzyme-linked immunosorbent assay (ELISA). Transplanted NSCs had significantly increased BMS scores (p < 0.05). Histological results showed that the grafted NSCs migrated from the injection site toward the injured area. NSCs transplantation significantly reduced the number of neutrophils and iNOS+/Mac-2+ cells at the epicenter of the injured area (p < 0.05). Meanwhile, mRNA levels of TNF-α, IL-1ß, IL-6 and IL-12 in the NSCs transplantation group were significantly decreased compared to the control group. Furthermore, NSCs inhibited the iNOS expression of BMDMs and the release of inflammatory factors by macrophages in vitro (p < 0.05). These results suggest that NSC transplantation could modulate SCI-induced inflammatory responses and enhance neurological function after SCI via reducing M1 macrophage activation and infiltrating neutrophils. Thus, this study provides a new insight into the mechanisms responsible for the anti-inflammatory effect of NSC transplantation after SCI.

Clinicopathological Parameters Influence Assessment of FDG SPECT in Gastric Cancer.

BACKGROUND/AIMS: To investigate the clinicopathological parameters influencing assessment of FDG SPECT in gastric cancer. METHODOLOGY: The frames of FDG SPECT and clinical data of 105 patients with gastric cancer were collected. The univariate and multivariate analyses were performed to assess the relationship between the visual assessment, SUV(max) and clinicopathological parameters. RESULTS: There were statistically significant in tumor size and pT stage between the positive and negative group (p < 0.01), while there was no statistically significant in gender, age, tumor localization, pN stage, histological type, adenocarcinoma differentiation (p > 0.05). Tumor size and pT stage were independent factors associated with visual assessment at multivariate analyses (p < 0.05). SUV(max) was positively correlated with age, tumor size and pT stage, respectively (p < 0.01). There was no statistically significant of SUV(max) in gender, tumor localization, pN stage, histological type, adenocarcinoma differentiation (p > 0.05). Age, tumor size and pT stage were independent factors related to SUV(max) (p < 0.05). CONCLUSIONS: Tumor size and depth of invasion were clinicopathological parameters influencing FDG SPECT assessment in gastric cancer independently. The relationship between tumor size, depth of invasion, expression of GLUT-1 and FDG imaging should be determined by further research.

Identifying the role of microRNAs in spinal cord injury.

Spinal cord injury (SCI) is medically and socioeconomically debilitating, and effective treatments are lacking. The elucidation of the pathophysiological mechanisms underlying SCI is essential for developing effective treatments for SCI. MicroRNAs (miRNAs) are small non-coding RNA molecules (18-24 nucleotides long) that regulate gene expression by interacting with specific target sequences. Recent studies suggest that miRNAs can act as post-transcriptional regulators to inhibit mRNA translation. Bioinformatic analyses indicate that the altered expression of miRNAs has an effect on critical processes of SCI physiopathology, including astrogliosis, oxidative stress, inflammation, apoptosis, and neuroplasticity. Therefore, the study of miRNAs may provide new insights into the molecular mechanisms of SCI. Current studies have also provided potential therapeutic clinical applications that involve targeting mRNAs to treat SCI. This review summarizes the biogenesis and function of miRNAs and the roles of miRNAs in SCI. We also discuss the potential therapeutic applications of miRNA-based interventions for SCI.

Effects of different sera conditions on olfactory ensheathing cells in vitro.

Transplantation of olfactory ensheathing cells (OEC) is a promising therapy in spinal cord injury (SCI) treatment. However, the therapeutic efficacy of this method is unstable due to unknown reasons. Considering the alterations in the culture environment that occur during OEC preparation for transplantation, we hypothesize that these changes may cause variations in the curative effects of this method. In this study, we compared OEC cultured in medium containing different types and concentrations of serum. After purification and passage, the OEC were cultured for 7 days in different media containing 5%, 10%, 15% or 20% fetal bovine serum (FBS) or rat serum (RS), or the cells were cultured in FBS-containing medium first, followed by medium containing RS. In another group, the OEC were first cultured in 10% FBS for 3 days and then cultured with rat spinal cord explants with 10% RS for another 4 days. An MTT assay and P75 neurotrophin receptor immunofluorescence staining were used to examine cell viability and OEC numbers, respectively. The concentration of neurotrophin-3 (NT-3), which is secreted by OEC into the culture supernatant, was detected using the enzyme-linked immunosorbent assay (ELISA). RT-PCR was applied to investigate the NT-3 gene expression in OEC according to different groups. Compared with FBS, RS reduced OEC proliferation in relation to OEC counts (χ2 = 166.279, df = 1, p < 0.01), the optical density (OD) value in the MTT assay (χ2 = 34.730, df = 1, p < 0.01), and NT-3 concentration in the supernatant (χ2 = 242.997, df = 1, p < 0.01). OEC cultured with spinal cord explants secreted less NT-3 than OEC cultured alone (F = 9.611, df = 5.139, p < 0.01). Meanwhile, the order of application of different sera was not influential. There was statistically significant difference in NT-3 gene expression among different groups when the serum concentration was 15% (χ2 = 64.347, df = 1, p < 0.01). In conclusion, different serum conditions may be responsible for the variations in OEC proliferation and function.

Progress in process parameters and mechanism research of polymer emulsion preparation.

As a new type of concrete admixture, polymer emulsion is mainly used to strengthen the properties of concrete by adhesion and physical and chemical crosslinking with cement in concrete. Under the background of construction in the new era, it is of great significance to elucidate all aspects of concrete performance under the action of polymer emulsion. In this paper, the main formation process of polymer emulsion is reviewed, the influence of synthetic materials required for polymerization on the polymerization process is discussed, and the regulating effects of reaction temperature, reaction time, admixtures, and treatment methods on the synthesis process of polymer emulsion are analyzed. The action mechanism of polymer emulsion on concrete was deeply investigated, and the synthesis method was studied to provide an important experimental and theoretical basis for the preparation of new emulsion materials and the process of emulsion polymerization. The problems of polymer emulsion raw materials, synthetic conditions, and synthetic methods are introduced. The future development trend of polymer emulsion is predicted and the future research ideas are put forward.

Security Analysis for Dynamic State Estimation of Power Systems With Measurement Delays.

This article is centered on the cybersecurity research of dynamic state estimation for power systems with measurement delays. Relying on mixed measurements from phasor measurement units (PMUs) and remote terminal units (RTUs), a delayed measurement model is constructed. A modified state estimator based on the Kalman filter (KF) is designed, which can obtain the optimal estimated states under measurement delays. Moreover, the measurement data transmitted from the sensor to the estimator are vulnerable to cyberattacks. Especially, false data-injection (FDI) attacks are frequently encountered in the power system state estimation (PSSE) process. In the case of measurement delays, an FDI attack strategy is designed to interfere with the state estimator and evade detection by the chi-square detector. By utilizing the attacked estimated information and the uncorrupted measurement information, two measurement residual vectors are designed. According to these two residual vectors, a chi-square-based attack detection method is proposed, which has the ability to detect the attack without being affected by the delayed measurements. The proposed KF algorithm and attack detection method are implemented on an IEEE 14-bus system and they are confirmed to be effective and feasible.

Event-Based Adaptive NN Fixed-Time Cooperative Formation for Multiagent Systems.

This article focuses on the fixed-time formation control problem for nonlinear multiagent systems (MASs) with dynamic uncertainties and limited communication resources. Under the framework of the backstepping method, a time-varying formation function is introduced in the controller design. To attain the prescribed transient and steady-state performance of MASs, a fixed-time prescribed performance function (FTPPF) is designed and the further coordinate transformation addressing the zero equilibrium point problem is removed. To achieve better approximating performance, a neural network (NN)-based composite dynamic surface control (CDSC) strategy is proposed, where the CDSC scheme is consisted of prediction errors and serial-parallel estimation models. According to the signals generated by the estimation models, disturbance observers are established to overcome the difficulty from approximating errors and mismatched disturbances. Moreover, an improved dynamic event-triggered mechanism and varying threshold parameters are constructed to reduce the signal transmission frequency. Via the Lyapunov stability theory, all the signals in the closed-loop system are semi-globally uniformly ultimately bounded. Finally, the simulation results verify the effectiveness of the developed CDSC strategy.

Extracellular vesicle-derived miR-511-3p from hypoxia preconditioned adipose mesenchymal stem cells ameliorates spinal cord injury through the TRAF6/S1P axis.

Extracellular vesicle (EV) from hypoxic adipose tissue-derived mesenchymal stem cells (AD-MSCs) play critical roles in spinal cord injury (SCI) by transferring miRNAs to target cells through fusion with the cell membrane. However, the role of miR-511-3p within the AD-MSCs -derived EV in SCI is largely unknown. Western blotting results demonstrated the secretion of EVs derived from AD-MSCs under hypoxia (Hyp-EVs) was more than those under normoxia (Nor-EVs), and miR-511-3p expression was more enriched in Hyp-EVs. PC12 cells were stimulated with lipopolysaccharide (LPS) to induce cell damage. AD-MSCs were transfected with miR-511-3p mimic or miR-511-3p inhibitor to induce EVs-miR-511-3p overexpression or silencing. Cells treated with Hyp-EVs-miR-511-3p mimic reduced LPS-induced apoptosis, alleviated inflammation and promoted proliferation, while cells treated with Hyp-EVs-miR-511-3p inhibitor aggravated LPS-induced apoptosis and inflammation, and suppressed proliferation. Luciferase reporter gene assay revealed tumor necrosis factor receptor-associated factor 6 (TRAF6) was a target downstream gene of miR-511-3p. A series of gain- and loss-of-function experiments verified that TRAF6 could antagonize the effects of Hyp-EVs-miR-511-3p on inflammation, cell apoptosis and viability. Furthermore, cells treated with CYM5541, an agonist of sphingosine-1-phosphate receptor 3 (S1PR3), reversed the inhibitory effect of Hyp-EVs-miR-511-3p mimic on S1PR3 expression, inflammation and cell apoptosis. Finally, intravenously injection of Hyp-EVs-miR-511-3p mimic into SCI model rats obviously reduced inflammation and promoted neurological function recovery. In conclusion, EVs-derived miR-511-3p from hypoxia preconditioned AD-MSCs ameliorates SCI via TRAF6/S1P/NF-κB pathway, which indicates that miR-511-3p may be a potential therapeutic target for SCI.

Traditional Chinese medicine together with high-dose vitamin C improves the therapeutic effect of western medicine against COVID-19.

OBJECTIVES: Traditional Chinese medicine has been reported to be effective in the treatment of epidemic diseases. Here, we aimed to investigate the effects of combined therapy of Chinese and western medicine on coronavirus disease 2019 (COVID-19). METHODS: A total of 60 patients diagnosed with COVID-19 were enrolled. Both the ordinary and severely affected patients were randomly divided into Groups A-C each with 10 cases each. The patients in Group A-C received Western medicine, Western medicine + traditional Chinese medicine, and Western medicine + traditional Chinese medicine + high dose of vitamin C, respectively. The time of disease recovery, symptoms disappearance, chest CT improvement, and tongue amelioration was recorded. Leukocyte, neutrophil and lymphocyte were monitored, as well as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalitonin (PCT), inflammatory factors, partial pressure of oxygen and carbon dioxide (PaCO2) and oxygenation index (PaO2). Urinary tract stones, liver function, and other side-effects such as gastrointestinal dysfunction were also investigated. RESULTS: Traditional Chinese medicine enhanced the effect of Western medicine, including the reduction of CRP, ESR, PCT, and inflammatory factors, and the increase of leukocyte, neutrophil, and lymphocyte counts, and the improvement of respiratory rate, PaO2, PaCO2, and oxygenation index. Traditional Chinese medicine combined with high-dose Vitamin C therapy more effectively shortened the time of disease recovery, symptom disappearance, chest CT improvement, and tongue amelioration. CONCLUSIONS: a combined therapy of Western medicine, traditional Chinese medicine, and high dose of Vitamin C results in a most effective outcome in the treatment of COVID-19.

[Construction of recombinant plasmid pIRES-GM-CSF-IL-21 and its therapeutic effect on orthotopically transplanted liver cancer in mice].

OBJECTIVE: To construct a recombinant plasmid pIRES-GM-CSF-IL-21, and to investigate its antitumor effect on tumors in the mice. METHODS: Fifty Bal b/c mice were included in this study. Cultured hepatoma H22 cells were inoculated in the left lobe of the liver to develop orthotopically transplanted liver tumor models. The mice with orthotopically transplanted liver tumor were randomly divided into 5 groups (n = 10): (1) Each mouse received injection of recombinant plasmid pIRES-GM-CSF-IL-21; (2) Received injection of plasmid pIRES-GM-CSF; (3) pIRES-IL-21; (4) Received injection of ampty plasmid pIRES (H22/neo group); (5) Received injection of PBS (H22 group) via the tail vein, respectively. Therefore, the anti-tumor effect was induced by both GM-CSF and IL-21, or by either of them alone. The serum levels of IFN-γ and IL-2 were detected by ELISA, and the cytotoxicity of spleen NK and CTL cells were tested by MTT colorimetry. RESULTS: Comparing with the H22 and H22/Neo groups, the tumor weight in the mice of H22/GM-CSF group was (0.603 ± 0.223) g, H22/IL21-treated group (0.583 ± 0.290) g and H22/GM-CSF-IL21-treated group (0.303 ± 0.323) g, significantly lower than that in the H22 group [(1.591 ± 0.280) g] and H22/Neo group [(1.489 ± 0.155) g]. Among them the tumor growth was most significantly inhibited in the H22/GM-CSF-IL-21 group (0.303 ± 0.323) g, compared with that of H22 and H22/neo groups (P < 0.01). But there was no significant difference between the tumor weights of the H22/GM-CSF group and H22/IL-21 group, and between the tumor weights of the H22 and H22/Neo groups (P > 0.05). The levels of IFN-γ and IL-2 in peripheral blood of mouse models treated with H22/GM-CSF-IL-21 were significantly increased than that in the H22/GM-CSF group and H22/IL-21 group (all P < 0.01), but significantly decreased in the H22group and H22/Neo group (P < 0.01). The anti-tumor activity of splenic NK cells and CTLs in the H22/GM-CSF-IL21 group was significantly enhanced (P < 0.01), compared with the significantly decreased in the H22 and H22/Neo groups. CONCLUSIONS: Our results demonstrate apparent antitumor effect of the plasmid pIRES-GM-CSF-IL-21 on the orthotopically transplanted liver tumor in mice. The combination of both pIRES-GM-CSF and IL-21 is more effective than that of pIRES/IL21 or pIRES/GM-CSF treatment alone. In addition, the plasmid pIRES-GM-CSF-IL-21 can also promote the secretion of IFN-γ and IL-2 in vivo, and enhance the cytotoxic activity of splenic NK and CTLs against the transplanted liver tumor.

[Expression of Semaphorin 3A after spinal cord injury].

OBJECTIVE: To investigate expression of Semaphorin 3A in rats after spinal cord injury and explore possible mechanism of inhibiting of axonal regeneration after SCI. METHODS: Forty healthy female SD rats, 8 weeks old, weighing (210.00±9.88) g, were randomly divided into control group(20 rats in group A) and model group(20 rats in group B). In control group, removal of T10 lamina and partial removal of T9 and T11 lamina were performed, and no further operation was performed on spinal cord (pseudo operation). In model group, the total T10 and partial T9, T11 partial lamina were incised and the spinal cord transection was performed to create animal models of spinal cord injury. The rats were perfused and spinal cord tissue obtained at 3, 7, 14, 28 and 42 days after surgery (4 rats in each group at each time point), respectively, and then HE staining was performed. Meanwhile, the expression of Semaphoring 3A was detected in accordance with the protocol of SP kit. RESULTS: After a simple spinal cord transection injury, hemorrhagic necrosis, localized edema, neurodegeneration, necrosis, and cyst formation occurred in the injured area, and glial scar formation occurred in glial cells. Semaphorin 3A expression levels in control group was low in the gray matter area. There was no expression of Semaphorin 3A in the injured area of spinal cord injury in model group 3 days after operation. On the 14th day, the expression of Semaphorin 3A in the injured area of spinal cord injury increased significantly and was at a high level. On the 28th day, the expression of Semaphorin 3A was moderate. On the 42th day, the positive expression of Semaphorin 3A returned to normal level. CONCLUSION: The increased expression of Semaphorin 3A after spinal cord injury may be one of the mechanisms that inhibit axonal regeneration.

Olfactory ensheathing cell transplantation alters the expression of chondroitin sulfate proteoglycans and promotes axonal regeneration after spinal cord injury.

Cell transplantation is a potential treatment for spinal cord injury. Olfactory ensheathing cells (OECs) play an active role in the repair of spinal cord injury as a result of the dual characteristics of astrocytes and Schwann cells. However, the specific mechanisms of repair remain poorly understood. In the present study, a rat model of spinal cord injury was established by transection of T10. OECs were injected into the site, 1 mm from the spinal cord stump. To a certain extent, OEC transplantation restored locomotor function in the hindlimbs of rats with spinal cord injury, but had no effect on the formation or volume of glial scars. In addition, OEC transplantation reduced the immunopositivity of chondroitin sulfate proteoglycans (neural/glial antigen 2 and neurocan) and glial fibrillary acidic protein at the injury site, and increased the immunopositivity of growth-associated protein 43 and neurofilament. These findings suggest that OEC transplantation can regulate the expression of chondroitin sulfate proteoglycans in the spinal cord, inhibit scar formation caused by the excessive proliferation of glial cells, and increase the numbers of regenerated nerve fibers, thus promoting axonal regeneration after spinal cord injury. The study was approved by the Animal Ethics Committee of the Medical College of Xi'an Jiaotong University, China (approval No. 2018-2048) on September 9, 2018.

Myelin Debris Stimulates NG2/CSPG4 Expression in Bone Marrow-Derived Macrophages in the Injured Spinal Cord.

Although the increased expression of members of the chondroitin sulfate proteoglycan family, such as neuron-glial antigen 2 (NG2), have been well documented after an injury to the spinal cord, a complete picture as to the cellular origins and function of this NG2 expression has yet to be made. Using a spinal cord injury (SCI) mouse model, we describe that some infiltrated bone marrow-derived macrophages (BMDMΦ) are early contributors to NG2/CSPG4 expression and secretion after SCI. We demonstrate for the first time that a lesion-related form of cellular debris generated from damaged myelin sheaths can increase NG2/CSPG4 expression in BMDMΦ, which then exhibit enhanced proliferation and decreased phagocytic capacity. These results suggest that BMDMΦ may play a much more nuanced role in secondary spinal cord injury than previously thought, including acting as early contributors to the NG2 component of the glial scar.