Honokiol exerts protective effects on neural myelin sheaths after compressed spinal cord injury by inhibiting oligodendrocyte apoptosis through regulation of ER-mitochondrial interactions.

OBJECTIVE: To investigate the effect of honokiol on demyelination after compressed spinal cord injury (CSCI) and it's possible mechanism. DESIGN: Animal experiment study. SETTING: Institute of Neuroscience of Chongqing Medical University. INTERVENTIONS: Total of 69 Sprague-Dawley (SD) rats were randomly divided into 3 groups: sham group (n=15), honokiol group (n=27) and vehicle group (n=27). After established CSCI model by a custom-made compressor successfully, the rats of sham group were subjected to the limited laminectomy without compression; the rats of honokiol group were subjected to CSCI surgery and intraperitoneal injection of 20 mg/kg honokiol; the rats of vehicle group were subjected to CSCI surgery and intraperitoneal injection of an equivalent volume of saline.Outcome measures: The locomotor function of each group was assessed using the Basso, Beattie and Bresnahan (BBB) rating scale. The pathological changes of myelinated nerve fibers of spinal cord in 3 groups were detected by osmic acid staining and transmission electron microcopy (TME). Immunofluorescence and Western blot were used to research the experessions of active caspase-3, caspase-12, cytochrome C and myelin basic protein (MBP) respectively. RESULTS: In the vehicle group, the rats became paralyzed and spastic after injury, and the myelin sheath became swollen and broken down along with decreased number of myelinated nerve fibers. Western blot analysis manifested that active caspase-3, caspase-12 and cytochrome C began to increase 1 d after injury while the expression of MBP decreased gradually. After intervened with honokiol for 6 days, compared with the vehicle group, the locomotor function and the pathomorphological changes of myelin sheath of the CSCD rats were improved with obviously decreased expression of active caspase-3, caspase-12 and cytochrome C. CONCLUSIONS: Honokiol may improve locomotor function and protect neural myelin sheat from demyelination via prevention oligodendrocytes (OLs) apoptosis through mediate endoplasmic reticulum (ER)-mitochondria pathway after CSCI.

Adenosine A2A Receptor in Bone Marrow-Derived Cells Mediated Macrophages M2 Polarization via PPARγ-P65 Pathway in Chronic Hypoperfusion Situation.

Background: The role of adenosine A2A receptor (A2AR) in the ischemic white matter damage induced by chronic cerebral hypoperfusion remains obscure. Here we investigated the role of A2AR in the process of macrophage polarizations in the white matter damage induced by chronic cerebral hypoperfusion and explored the involved signaling pathways. Methods: We combined mouse model and macrophage cell line for our study. White matter lesions were induced in A2AR knockout mice, wild-type mice, and chimeric mice generated by bone marrow cells transplantation through bilateral common carotid artery stenosis. Microglial/macrophage polarization in the corpus callosum was detected by immunofluorescence. For the cell line experiments, RAW264.7 macrophages were treated with the A2AR agonist CHS21680 or A2AR antagonist SCH58261 for 30 min and cultured under low-glucose and hypoxic conditions. Macrophage polarization was examined by immunofluorescence. The expression of peroxisome proliferator activated receptor gamma (PPARγ) and transcription factor P65 was examined by western blotting and real-time polymerase chain reaction (RT-PCR). Inflammatory cytokine factors were assessed by enzyme-linked immunosorbent assay (ELISA) and RT-PCR. Results: Both global A2AR knockout and inactivation of A2AR in bone marrow-derived cells enhanced M1 marker expression in chronic ischemic white matter lesions. Under low-glucose and hypoxic conditions, CGS21680 treatment promoted macrophage M2 polarization, increased the expression of PPARγ, P65, and interleukin-10 (IL-10) and suppressed the expression of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). The CGS21680-induced upregulation of P65 and IL-10 was abolished in macrophages upon PPARγ knockdown. The downregulation of TNF-α and IL-1ß by CGS21680 was less affected by PPARγ knockdown. Conclusions: In the cerebral hypoperfusion induced white matter damage, A2AR signaling in bone marrow-derived cells induces macrophage M2 polarization and increases the expression of the anti-inflammatory factor IL-10 via the PPARγ-P65 pathway, both of which might explain its neuroprotective effect.

Integrative transcriptome analysis identified a BMP signaling pathway-regulated lncRNA AC068643.1 in IDH mutant and wild-type glioblastomas.

Glioblastomas (GBMs) are classified into isocitrate dehydrogenase (IDH) mutant (IDH MT) and wild-type (IDH WT) subtypes, and each is associated with distinct tumor behavior and prognosis. The present study aimed to investigate differentially expressed long non-coding (lnc)RNAs and mRNAs between IDH MT and IDH WT GBMs, as well as to explore the interaction and potential functions of these RNAs. A total of 132 GBM samples with RNA profiling data (10 IDH MT and 122 IDH WT cases) were obtained from The Cancer Genome Atlas, and 62/78 and 142/219 up/downregulated lncRNAs and mRNAs between IDH MT and IDH WT GBMs were identified, respectively. Multivariate Cox analysis of the dysregulated lncRNAs/mRNAs identified three-lncRNA and fifteen-mRNA signatures with independent prognostic value, indicating that these RNAs may serve roles in determining distinct tumor behaviors and prognosis of patients with IDH MT/WT GBMs. Functional analysis of the three lncRNAs revealed that they were primarily associated with cell stemness or differentiation. Pearson's correlation analysis revealed that the protective lncRNA AC068643.1 was significantly positively correlated with two key bone morphogenetic protein (BMP) signaling-associated mRNAs, Bone morphogenetic protein 2 (BMP2) and Myostatin (MSTN), from the 15 mRNAs. Further in vitro studies demonstrated that BMP2 and MSTN directly stimulated AC068643.1 expression. In conclusion, the present study identified a BMP signaling pathway-regulated lncRNA AC068643.1, which may contribute to the different tumor behaviors observed between IDH MT and IDH WT GBMs.

[AQP4 expression in the brains of patients with glioblastoma and its association with brain edema].

OBJECTIVE: To investigate the expression of aquaporin-4 (AQP4) in the brains of patients with glioblastoma and its association with brain edema. METHODS: Immunofluorescence cytochemistry and western blot tests were performed to detect the expression of AQP4 in the brain tumors and the adjacent tissues in 30 patients with glioblastoma. The association between AQP4 and the extent of brain edema was analysed. RESULTS: The AQP4 immunoreactive cells were mainly astrocytes in the brains, which were extensively distributed in the intracytoplasm. Higher expressions of AQP4 were found in the brain tumors and adjacent tissues in the patients with glioblastoma than in the normal controls (P<0.05). More AQP4 were distributed in the tumor adjacent tissues than in the tumors (P<0.05). The AQP4 was positively correlated with the extent of brain edema. CONCLUSION: AQP4 overexpress in the brain tumors and adjacent tissues, which is associated with the extent of brain edema. Cytotoxic and vasogenic edemas may coexist in the cerebral edema induced by glioblastoma.

MiR-206 is down-regulated and suppresses cell proliferation by targeting FOXP1 in brain gliomas.

Aberrant expression of miR-206 has been repeatedly found and demonstrated to play crucial roles in cancers. However, the role of miR-206 in brain glioma remains unclear. To address this issue, we detected miR-206 expression of 60 gliomas and 18 normal peritumor tissues, and found that miR-206 is significantly down-regulated in gliomas. Further in silico analysis of 198 glioma samples from the Chinese Glioma Genome Atlas (CGGA) indicated that miR-206 is significantly down-regulated in high grade gliomas and that miR-206 predicts favorable patients' prognosis. Notably, we found that miR-206 expression is negatively correlated with Ki-67 staining, indicating a proliferative inhibition of miR-206 in gliomas. To explore the crucial role of miR-206 in gliomas, we constructed miR-206 stably overexpressed LN229 glioma cell lines and found that the proliferation is significantly inhibited. Through flow cytometry (FCM) analyses, we found that the apoptotic rate is increased and the cell cycle is arrested in LN229 cells after overexpression of miR-206. Bioinformatic analysis, qPCR, western blot and luciferase assay indicated that the Forkhead Box Protein 1 (FOXP1) is a direct target of miR-206 in gliomas. Overexpression of FOXP1 could partially rescue the proliferative inhibition in the miR-206 stably overexpressed LN229 cells. In summary, our results suggest that miR-206 might function as a tumor suppressor of gliomas by inhibition of proliferation and could serve as a promising candidate for therapeutic applications in glioma by targeting FOXP1.

p53-Mediated oligodendrocyte apoptosis initiates demyelination after compressed spinal cord injury by enhancing ER-mitochondria interaction and E2F1 expression.

Oligodendrocyte apoptosis mediated demyelination is a pathological change characteristic of compressed spinal cord injury (CSCI). However, the mechanism of demyelination due to oligodendrocyte apoptosis is not known. In this study, after successfully establishing a rat CSCI model using a custom-made compressor, we investigated the pathological changes, MBP expression, as well as apoptosis-related protein (p53, active caspase-3) expression to determine whether or not apoptosis and demyelination occurred after injury. To understand the possible mechanism of oligodendrocyte apoptosis, caspase-12 and cytochrome C were analyzed to explore the relationship between oligodendrocyte apoptosis and endoplasmic reticulum(ER)-mitochondria interaction. The transcription factor, E2F1, was also detected by immunofluorescence and Western blot assays. The results showed that CSCI increased the expression levels of p53, E2F1 and active caspase-3 followed by the swelling and breakdown of myelin sheaths. The number of myelinated nerve fibers also decreased with down-regulated expression of MBP. Expression levels of caspase-12 and cytochrome C were enhanced along with a reduction in the number of oligodendrocytes. After treatment of CSCI in rats with Pifithrin-µ(PFT-µ), a specific inhibitor of p53, pathomorphological changes of myelin sheath improved significantly. Expression levels of E2F1, active caspase-3, caspase-12 and cytochrome C were down-regulated, consistent with reduced the number of apoptotic oligodendrocytes. These results demonstrated that over-expression of p53 could mediate oligodendrocyte apoptosis thus resulting in demyelination in two ways; by enhancing ER-mitochondria interaction and by triggering the E2F1 mediated apoptosis pathway.

Pyrrolidine dithiocarbamate sensitizes U251 brain glioma cells to temozolomide via downregulation of MGMT and BCL-XL.

The current study investigated the effect of pyrrolidine dithiocarbamate (PDTC) on the proliferation, apoptosis, cell cycle and sensitivity to temozolomide (TMZ) of the U251 glioma cell line. Proliferation, apoptosis and cell cycle analysis of U251 cells following treatment with PDTC and TMZ was determined by an MTT assay and flow cytometry, respectively. The mRNA and protein expression levels of O-6-methylguanine-DNA methyltransferase (MGMT), B-cell lymphoma extra-large (BCL-XL) and survivin were further determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting analysis. The results revealed that treatment with TMZ, PDTC and TMZ + PDTC significantly inhibited cell proliferation, induced apoptosis and contributed to cell cycle arrest in U251 cells. A combination of PDTC and TMZ induced the highest rates of proliferation inhibition and apoptosis. PDTC treatment markedly reduced the expression levels of MGMT, BCL-XL and survivin. The expression levels of MGMT and BCL-XL, were significantly upregulated by TMZ but not by combination treatment of TMZ and PDTC. The results of the present study suggest that treatment with PDTC inhibits cell proliferation, induces apoptosis and cell cycle arrest, and enhances sensitivity to TMZ in U251 cells, which is partly induced by downregulation of MGMT and BCL-XL.

Risk Factors for the Rupture of Middle Cerebral Artery Bifurcation Aneurysms Using CT Angiography.

BACKGROUND AND PURPOSE: To investigate the clinical and morphological characteristics associated with risk factors for the rupture of bifurcation-type middle cerebral artery aneurysms (MCAAs). METHODS: A total of 169 consecutive patients with 177 bifurcation-type MCAAs were reviewed from August 2011 to January 2016. Based on the clinical and morphologic characteristics findings, the risk factors of aneurysm rupture were assessed using statistical methods. RESULTS: Age, cerebral atherosclerosis, no hypertension, hypertension grade 2 and coronary artery disease (CAD) were negatively correlated with aneurysm rupture. The mean diameter (MD) of the parent and two daughter arteries was negatively correlated with rupture. Aneurysms with irregularity, depth, width, maximum size, aspect ratio, depth-to-width ratio, bottleneck factor, and size ratio were positively correlated with rupture. The multivariate logistic regression model revealed that irregular shape (odds ratio (OR) 2.697) and aspect ratio (OR 3.723) were significantly and positively correlated with rupture, while cerebral atherosclerosis (OR 0.033), CAD (OR 0.080), and MD (OR 0.201) were negatively correlated with rupture. Receiver operating characteristic analysis revealed that the threshold value of the aspect ratio and MD were 0.96 and 2.43 mm, respectively. CONCLUSIONS: Cerebral atherosclerosis and CAD are protective factors against rupture. Morphological characteristics such as an aneurysm with an irregular shape, a high aspect ratio (>0.96) and a small MD (<2.43 mm) are likely better predictors of rupture.

Microarray analysis of the aberrant microRNA expression pattern in gliomas of different grades.

Previous studies have focused on miRNA expression in brain gliomas. However, both the expression pattern of miRNAs in gliomas of different grades and various miRNAs involved in malignant progression of gliomas are poorly understood. In the present study, we used miRNA microarray-based screening to investigate the miRNA expression profile in gliomas, which was further verified by qRT-PCR in selected miRNAs. In total, we found 13 differentially expressed miRNAs between gliomas and their matched surrounding tissues. Among them, 12 miRNAs were upregulated and only one (miR-4489) was downregulated compared with the control. Furthermore, the lower expression level of miR-4489 was confirmed by qRT-PCR in 26 glioma samples. Our microarray result revealed 8, 9 and 15 aberrantly expressed miRNAs in gliomas of World Health Organization (WHO) grade II-IV, respectively. Gene Ontology (GO) and Pathway analysis indicated that target genes of the 13 miRNAs were significantly enriched in central nervous system- and tumor-related biological processes and signaling pathways. The dysregulated miRNAs identified in the present study contribute to the tumorigenesis and malignant progression of gliomas and may serve as useful markers for advanced glioma pathological grading and prognosis.