Autophagy and myocardial ischemia/reperfusion injury

Autophagy is a lysosome-dependent degradative pathway which is characterized by cytoplasmic vacuolization. However, it is not just a simple degradative pathway. Research shows that autophagy is related to many diseases, such as neurodegenerative disease, malignant tumor, ageing, pathogenic microorganism infection, myocardial ischemia/reperfusion injury and so on. Autophagy exactly exists in myocardial ischemia/reperfusion injury, and it becomes a new research hotspot. This review will focus on the occurrence and development of autophagy and its role, signal transduction and research status in myocardial ischemia/reperfusion injury.     

Autophagy and tumor

Autophagy is a vacuolar process of cytoplasmic degradation by lysosome which ubiquitously occurring in all eukaryotic cells. The researches of autophagy have made great progress with the development of the yeast model and genetic technology. This review will summarize the determination of autophagy, its relationship with apoptosis and its role in the tumor treatment in order to give a comprehensive understanding of the function of autophagy.     

Changes of aquaporin expression in blood-brain barrier induced by glioma cells

AIM:To investigate the effects of glioma cells on aquaporin expression in blood-brain barrier and their importance in pathophysiology.METHODS:A blood-brain barrier model was established by coculture of ECV304 and astrocytesin vitro. HPLC was used to determine the change of water transport ofin vitroblood-brain barrier model after the influence of glioma cells. The expression levels of AQP1 and AQP4 were analyzed by semiquatitative RT-PCR.RESULTS:Glioma cells decreased expression level of AQP4 of astrocytes and induced abnormal expression of aquaporin-1 in endothelial cell line. The water transport ofin vitroblood-brain barrier model from luminal side to abluminal side was increased after coculture with glioma cells.CONCLUSION:The vasogenic brain edema induced by glioma cells may not be the result of hyperpermeability of blood-brain barrier to macromolecules in plasma. The changes of aquaporin expression may be the molecular basis of brain edema induced by glioma cells.     

Expression of B7-H4 in human glioma tissues and its clinical significance

AIM: To investigate the expression of B7-H4 in human glioma tissues and its clinical significance. METHODS: The histological staging of 150 cases of human glioma tissues was determined by HE staining. Immunohistochemistry was performed to study the protein level of B7-H4 in 150 human glioma specimens. Furthermore, the relationships between the expression level of B7-H4 and clinicopathological parameters, as well as patients survival rate, were analyzed. RESULTS: HE staining result indicated that there were 12 cases staged as stage I, 50 cases stage II, 39 cases stage III and 49 cases stage IV in 150 glioma specimens. Ninety-seven cases highly expressed B7-H4 in total 150 glioma samples with a 64.7% high expression rate. The histological grade of the tissues with high B7-H4 expression was mostly III~IV. There were 53 cases with low B7-H4 expression in the total 150 glioma patients with a 35.3% low expression rate. The histological grade of the tissues with low B7-H4 expression was mostly I~II. The B7-H4 expression was related to the age of the patients (P<0.01) and the pathological grade of glioma (P<0.01), but not related to the location of glioma (P>0.05). Kaplan-Meier survival curves demonstrated that increased B7-H4 expression was associated with shorter overall survival time (P<0.01). Multivariate Cox regression analysis revealed that B7-H4, age, sex and pathological grade were independent prognostic factors in glioma patients. CONCLUSION: B7-H4 is expressed in most of glioma tissues. B7-H4 may be a novel prognostic biomarker and a new target of molecular therapy for gliomas.     

Roles of microRNAs in glioma

MicroRNAs (miRNAs) are critical regulators of gene expression. These small, non-coding RNAs are believed to regulate more than one third of protein-coding genes, and have been implicated in the control of many biological processes, including the biology of glioma. The functional significance in some of the miRNAs begins to emerge. This paper reviews the biogenesis of miRNAs, their roles in neuronal development and tumorigenesis of gliomas, and their contribution as tumor biomarkers. Research in this area is quickly gathering pace and is illuminating important aspects of the diseases that may ultimately lead to novel therapeutic interventions, as well as diagnostic and prognostic tools for brain tumors.     

Effect of EZH2 regulating Wnt/β-catenin signaling pathway on apoptosis of brain glioma cells

AIM: To investigate the effect of enhancer of zeste homolog 2 (EZH2) regulating Wnt/β-catenin signaling pathway on the apoptosis of brain glioma cell lines. METHODS: The expression level of EZH2 in glioma cell lines U87, H4 and U251 and normal human astrocytes (NHA) was detected by RT-qPCR and Western blot. The EZH2 siRNA and siRNA control were transfected into the H4 cells. The cell viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. Caspase-3 activity was detected by spectrophotometry. The expression levels of the key protein β-catenin of the Wnt/β-catenin signaling pathway and the downstream target molecule c-Myc were determined by Western blot. After the H4 cells transfected with EZH2 siRNA were treated with an activator of Wnt/β-catenin signaling pathway, the apoptosis rate was measured by flow cytometry, and the expression of β-catenin and c-Myc was determined by Western blot. RESULTS: The mRNA and protein expression levels of EZH2 in the glioma cell lines U87, H4 and U251 were significantly higher than those in NHA (P<0.05). The expression of EZH2 at mRNA and protein levels in the H4 cells was higher than that in U87 cells and U251 cells (P<0.05). EZH2 siRNA obviously inhibited the expression of EZH2 at mRNA and protein levels in the H4 cells. Knockdown of EZH2 expression decreased the viability of H4 cells, the apoptotic rate was significantly increased, and the activity of caspase-3 was significantly increased in the cells (P<0.05). Knockdown of EZH2 expression also inhibited the expression of β-catenin and c-Myc. The activator of Wnt/β-catenin signaling pathway reduced the apoptosis rate of H4 cells induced by down-regulation of EZH2, and reduced the activity of caspase-3 in the cells. CONCLUSION: EZH2 is over-expressed in glioma cells. Down-regulation of EZH2 expression induces apoptosis of glioma cells by inhibiting the activation of Wnt/β-catenin signaling pathway.     

芍药黑斑病病原菌鉴定及其对杀菌剂敏感性分析

对在江苏省扬州市芍药(Paeonialactiflora)叶片上发现的一种黑斑病,采集其病叶,分离和纯化病原物,根据柯赫氏法则明确其致病性。基于病原物形态特征和多基因(r DNA-ITS、endo PG、OPA2-1、Alt a 1)序列联合分析,鉴定该病原物为链格孢(Alternaria alternata)。该病原菌的最适生长条件是:温度为28℃,p H 7.0,最适碳源为可溶性淀粉,最适氮源为硝酸钾。室内毒力测定发现,在测试的4种杀菌剂中,嘧菌酯和吡唑醚菌酯乳油对病原菌离体生长的抑制作用较强,而戊唑醇和异菌脲对其生长的抑制作用较差。     

Effect of down-regulation of X-box binding protein 1 gene expression on viability and apoptosis of glioma cells

AIM: To investigate the effect of down-regulation of X-box binding protein 1 (XBP1) expression on the viability and apoptosis of glioma cells. METHODS: The mRNA expression of XBP1 in the glioma tissues was detected by qPCR. Small interfering RNA (siRNA) interfering with XBP1 expression (XBP1-siRNA) was transfected into human brain glioma U251 cells. At the same time, control group (the cells without special treatment) and negative control (NC-siRNA) group (transfected with siRNA without any interference) were set up. The mRNA expression of XBP1 in the 3 groups 48 h after transfection was detected by qPCR. The protein levels of XBP1, proliferating cell nuclear antigen (PCNA), B-cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated X protein (Bax), cyclin D1 (cyclin D1), phosphatidylinositol 3-kinase (PI3K) and phosphorylated Akt (p-Akt) were determined by Western blot. The cell viability was measured by CCK-8 assay. The cell cycle distribution and apoptosis were analyzed by flow cytometry. RESULTS: The expression level of XBP1 in the glioma tissues was significantly higher than that in the tumor adjacent tissues (P<0.05). The XBP1 expression at mRNA and protein levels was significantly decreased in the cells transfected with XBP1-siRNA (P<0.05). No statistically significant difference of the cell viability, cell cycle, apoptotic rate and the protein levels of PCNA, Bcl-2, Bax, cyclin D1, PI3K and p-Akt between NC-siRNA group and control group was observed. Compared with control group, the cell viability, S-phase cells and the protein levels of PCNA, Bcl-2, cyclin D1, PI3K, and p-Akt in XBP1-siRNA group were decreased significantly, and the apoptotic rate, G₀/G₁-phase cells and Bax protein expression were significantly increased (P<0.05). CONCLUSION: Down-regulation of XBP1 gene expression in brain glioma cells reduces the viability of cancer cells, blocks the cells in G₁ phase and promote apoptosis. The mechanism is related to the inhibition of PI3K/Akt signaling pathway.     

miR-205 inhibits invasion of glioma cells via targeting TBX18

AIM: To explore the expression pattern of microRNA-205 (miR-205) in glioma tissues and its role in the invasion of glioma cells. METHODS: The expression of miR-205 and TBX18 was detected by real-time PCR and immunohistochemical observation, respectively. Transwell assay was used to examine the invasion change of U251 glioma cells after miR-205 overexpression via miR-205 mimics or decrease in miR-205 expression by miR-205 inhibitor. The target of miR-205 was searched by bioinformatics analysis combined with experimental analysis. The protein level of TBX18 was determined by Western blotting after siRNA transfection and Transwell assay was conducted. RESULTS: miR-205 expression was downregulated in 82.6% of detected glioma tissues and TBX18 was significantly overexpressed in glioma tissues compared with normal tissues. miR-205 overexpression remarkably inhibited the invasion potential of U251 glioma cells with a decrease in the invasive cells (P<0.01), while inhibition of miR-205 significantly enhanced the invasion ability of U251 cells. Mechanically, miR-205 directly targeted TBX18 and downregulation of TBX18 also significantly inhibited the invasion potential of U251 cells with a decrease in the invasive cells (P<0.01). CONCLUSION: miR-205 expression is decreased in glioma, and miR-205 inhibits glioma cell invasion via targeting TBX18. Our research contributes to the mechanisms responsible for glioma invasion and provides theoretical base for developing new therapeutic strategy to treat glioma.     

Effect of autophagy in traumatic brain injury

Autophagy is a metabolic process of eukaryotic cells. When lacking of nutrient and energy, the cells obtain biosynthetic materials by degrading the organelles and recycling the proteins to maintain homeostasis. Traumatic brain injury (TBI) is a common kind of mechanic injury, usually with a poor outcome. Accumulated evidence indicates that the activity of autophagy increases after TBI. However, its implication for nervous tissue is still controversy. On one hand, autophagy exerts a protective effect on the neural cells. On the other hand, autophagy can also induce cell death exacerbating neural injury. This review focuses on the processes of autophagy and its roles in TBI, which may provide some novel therapeutic strategies.     

Clinical significance of 4-1BBL protein expression in human glioma tissues

AIM: To investigate the expression of 4-1BBL(CD137L) protein in human glioma tissues, and to analyze its clinical significance. METHODS: The expression levels of 4-1BBL protein in 82 human glioma specimens were measured by the method of immunohistochemistry. The correlation of 4-1BBL protein level with histopathologic features and survival time was analyzed. RESULTS: 4-1BBL protein positive cells were observed in human brain astrocytic tumors, which were not found in meningioma and normal brain tissues. In our study, the expression of 4-1BBL protein in 3 cases of normal brain tissues was negative. The expression of 4-1BBL protein in 31 cases of glioma specimens were positive, and total positive rate was 37.8% (31/82). The expression of 4-1BBL protein was related to the survival time and age of the patients, but not related to the pathological grade of glioma. Statistically, the patients with positive expression of 4-1BBL protein had longer survival time (P<0.05). CONCLUSION: Expression of 4-1BBL protein may have reference value to predict the prognosis of patients with glioma.     

Histone deacetylase SIRT1 and cell autophagy

.Sirtuin 1 (SIRT1), one of the nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylases, plays an important role in regulating cell cycle, cell aging, apoptosis and metabolism. Autophagy, a vital basic phenomenon that wildly exists in eukaryotic cells, plays an important part in waste scavenging, structure reestablishment, growth and development. In recent years, more and more attention has been paid to the connection between SIRT1 and autophagy. Clarifying the relationship between SIRT1 and autophagy will be of great importance in preventing and controlling aging-related diseases. This article overviews its research advancement.     

Research progress of glioma cell origin

Glioma, a common primary brain tumor, is considered to be incurable, and easy to relapse. The median survival of the patients with glioma after treatment is only 15 to 19 months. The high heterogeneity of glioma is the main reason leading to poor clinical treatment, and the underlying mechanism is closely related to the cell origin of glioma. Therefore, to elucidate the cell origin of glioma is important to further study the mechanism of tumor formation and develop effective treatment programs. For a long time, studies have attempted to speculate on the cell origin of glioma based on the morphological characteristics, but agreements still haven't been reached. This review focuses on the most probable origin cells, such as neural stem cells, astrocytes, oligodendrocyte progenitor cells and neurons.     

Nuciferine promotes autophagy and reduces macrophage foaming by inhibiting PI3K/Akt/mTOR signaling pathway

AIM To investigate the effect of nuciferine （NUF) on the formation of foam cells and its possible molecular mechanism. METHODS Human monocyte-macrophage cell line THP-1 was induced by oxidized low-density lipoprotein (Ox-LDL) to establish foam cell model, and simultaneously treated with NUF at 5, 10 or 20 μmol/L. Oil red O staining was used and total cholesterol content was measured to observe the effect of NUF on foam cell formation. Autophagy flow was detected by immunofluorescence, and autophagosomes were detected by transmission electron microscopy. The protein levels of microtubule-associated protein 1 light chain 3 (LC3), P62, phosphorylated protein kinase B (p-Akt) and phosphorylated mammalian target of rapamycin (p-mTOR) were determined by Western blot. 3-Methyladenine (3-MA), an autophagy inhibitor, was used to inhibit autophagy and to observe whether NUF inhibited foam cell formation by regulating autophagy. RESULTS Compared with control group, the intracellular lipid deposition and total cholesterol content in Ox-LDL group were increased. Compared with Ox-LDL group, the intracellular lipid deposition and total cholesterol content in NUF group were decreased, while autophagy flow and number of autophagosomes were increased. The inhibitory effect of NUF on cell foaming was weakened after 3-MA treatment. Moreover, NUF decreased the protein levels of p-mTOR and p-Akt. CONCLUSION Nuciferine may promote autophagy by inhibiting phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR signaling pathway, thus reducing intracellular lipid deposition and formation of foam cells.     

Effects of chemotherapy on free radicals in the rat glioma

AIM: To observe the role of free radicals in the inhibitory effect of chemotherapy on glioma cells. METHODS: C6 glioma cells were cultured in vitro, and treated with carmustine (B), teniposide (V), or/and nimodipine (N). Furthermore, the glioma-bearing rats were treated with B plus N, B+V+lisplatin (D)+N, or B+V+D+N+angiotensin Ⅱ. The MDA content and superoxide dismutase (SOD) activity in the culture supernatant and cortical brain tissue were assayed. RESULTS: B, V and N significantly decreased MDA content and SOD activity in the supernatant of glioma cell culture and C6 glioma cells. Chemotherapy reduced MDA content and increased SOD activity in the cortical brain tissue of tumor-bearing rats, with highest efficiency in B+V+D+N+angiotensin Ⅱ group. The survival time of tumor-bearing rats in B+V+D+N+angiotensin Ⅱ group was longer than that in other chemotherapy group. CONCLUSION: The antitumor effects of combined chemotherapy may be involved in the free radical metabolism.     

植物细胞选择性自噬研究进展

植物在生长发育和响应环境胁迫过程中不断产生受损的细胞器和蛋白质等,这些物质必须被及时且适宜的降解。其中,细胞自噬就是一个在进化上保守的主要降解途径。自噬体通过受体蛋白选择性地识别并靶向特异的组分和蛋白复合物,然后传递至液泡中降解,使其能够循环再利用,从而调节细胞内的关键反应过程。近些年的研究揭示了自噬在植物生命活动的多个过程中均发挥重要作用。本文中主要综述了植物细胞选择性自噬的最新研究进展,包括自噬体形成过程、货物识别、分类以及在生长发育、植物免疫和响应非生物胁迫中的作用。     

Effects of SRSF9/SRp30c on proliferation and migration abilities of glioma cells by regulating GRβ

AIM: To investigate the expression of serine-arginine-rich splicing factor 9/serine-arginine-rich protein 30c (SRSF9/SRp30c) and glucocorticoid receptor β (GRβ) in the glioma cells and the relationship of them. METHODS: Small interfering RNA (siRNA) was used to knock down the expression of SRSF9 in the U87 cells. Short hairpin RNA (shRNA) derived from lentivirus was used to establish U87 stable knockdown cell line. Fluorescence microscopy was used to observe and detect transfection efficiency. The expression of GRβ and SRSF9/SRp30c at mRNA and protein levels was determined by RT-qPCR and Western blot. The cell viability, colony formation ability and migration ability were measured by CCK-8 assay, colony formation assay and wound healing experiment. RESULTS: The mRNA and protein levels of SRSF9/SRp30c and GRβ in the U87 cells were both down-regulated after knockdown of SRSF9 (P<0.05). Fluorescence microscopic observation showed that a stable cell line was constructed successfully, and the transfection efficiency exceeded 80%. After knockdown of SRSF9 expression in the U87 cells, the cell viability and colony formation ability were reduced (P<0.05). The migration ability was weakened significantly after SRSF9 was knocked down (P<0.05). CONCLUSION: SRSF9/SRp30c may promote the proliferation and migration of the glioma cells by regulating GRβ.     

Role of autophagy inhibitor 3-methyladenine in the injury of U251 cells induced by H2O2

AIM: To investigate the role of autophagy inhibitor 3-methyladenine(3-MA) in the injury of U251 glioma cells induced by H₂O₂. METHODS: The following groups in this study were set up: control group, 10 mmol/L 3-MA group, 1 mmol/L H₂O₂ group and 1 mmol/L H₂O₂ +10 mmol/L 3-MA group. The viability of U251 cells in each group was detected by MTT assay. Autophagic vacuoles in the cells were observed by staining with MDC. The cells were stained with Hoechst 33342 to determine the chromatin condensation. Cell apoptotic ratio was measured by flow cytometry analysis. RESULTS: Compared with control group, no effect of 3-MA on the viability of U251 cells was observed. In H₂O₂ group, the cell viability decreased and cell apoptotic ratio increased.The autophagic vacuoles and nuclear chromatin condensation in the cells were also detected. Compared with H₂O₂ group, addition of 3-MA inhibited the increase in autophagic vacuoles but exacerbated the apoptosis. CONCLUSION: Autophagy inhibitor 3-MA inhibits autophagy partially, but exacerbates apoptosis in U251 cells, indicating that autophagy exerts protective effect in the process of injury in U251 cells induced by H₂O₂.     

Advances in microautophagy

Autophagy has been originally described as a key process which balances the survival and death of cells by regulating the proliferation. It is already known that macroautophagy, microautophagy and chaperone-mediated autophagy are the 3 subtypes. In this paper, we attempt to summarize the recent information about microautophagy.