Updated Understanding of the Glial-Vascular Unit in Central Nervous System Disorders / 神经科学通报·英文版

The concept of the glial-vascular unit (GVU) was raised recently to emphasize the close associations between brain cells and cerebral vessels, and their coordinated reactions to diverse neurological insults from a "glio-centric" view. GVU is a multicellular structure composed of glial cells, perivascular cells, and perivascular space. Each component is closely linked, collectively forming the GVU. The central roles of glial and perivascular cells and their multi-level interconnections in the GVU under normal conditions and in central nervous system (CNS) disorders have not been elucidated in detail. Here, we comprehensively review the intensive interactions between glial cells and perivascular cells in the niche of perivascular space, which take part in the modulation of cerebral blood flow and angiogenesis, formation of the blood-brain barrier, and clearance of neurotoxic wastes. Next, we discuss dysfunctions of the GVU in various neurological diseases, including ischemic stroke, spinal cord injury, Alzheimer's disease, and major depression disorder. In addition, we highlight the possible therapies targeting the GVU, which may have potential clinical applications.

Digoxin Ameliorates Glymphatic Transport and Cognitive Impairment in a Mouse Model of Chronic Cerebral Hypoperfusion / 神经科学通报·英文版

The glymphatic system plays a pivotal role in maintaining cerebral homeostasis. Chronic cerebral hypoperfusion, arising from small vessel disease or carotid stenosis, results in cerebrometabolic disturbances ultimately manifesting in white matter injury and cognitive dysfunction. However, whether the glymphatic system serves as a potential therapeutic target for white matter injury and cognitive decline during hypoperfusion remains unknown. Here, we established a mouse model of chronic cerebral hypoperfusion via bilateral common carotid artery stenosis. We found that the hypoperfusion model was associated with significant white matter injury and initial cognitive impairment in conjunction with impaired glymphatic system function. The glymphatic dysfunction was associated with altered cerebral perfusion and loss of aquaporin 4 polarization. Treatment of digoxin rescued changes in glymphatic transport, white matter structure, and cognitive function. Suppression of glymphatic functions by treatment with the AQP4 inhibitor TGN-020 abolished this protective effect of digoxin from hypoperfusion injury. Our research yields new insight into the relationship between hemodynamics, glymphatic transport, white matter injury, and cognitive changes after chronic cerebral hypoperfusion.

Effect of 14,15-EET on Inflammatory Responses of BV2 Cells After Oxygen and Glucose Depriviation/Reoxygenation / 医药导报

Objective To explore the effect of 14,15-epoxyeicosatrienoic acids (14,15-EET) on the inflammatory response of BV2 cells under oxygen and glucose depriviation/reoxygenation (OGD/R) conditions.Methods BV2 cells were randomly divided into three groups,blank control group,vehicle control group,and 14,15-EET group.Under treatment of 14,15-EET,the concentration of inflammatory factor in BV2 cell culture media was detected by ELISA at different time points (reoxygenation for 0,3,6,12,24 h) after OGD1h.The viability of BV2 cells was detected by MTT assay at different time points.At the same conditions,using Transwell migration experiment,migration ability of BV2 cells was observed.Results The 14,15-EET group had the lower levels of inflammatory factor secretion,lower viability and weaker ability of migration than the vehicle control group.The above results were most statistically significant at OGD1h/R12h.Conclusion 14,15-EET can inhibit the inflammation of BV2 cells induced by the injury of OGD reperfusion.

Small RNA interference-mediated gene silencing of TREK-1 potassium channel in cultured astrocytes / 华中科技大学学报（医学）（英德文版）

This study was aimed to examine the effect of TREK-1 silencing on the function of astrocytes. Three 21-nucleotide small interfering RNA (siRNA) duplexes (siT1, siT2, siT3) targeting TREK-1 were constructed. Cy3-labeled dsRNA oligmers were used to determine the transfection efficiency in cultured astrocytes. TREK-1-specific siRNA duplexes (siT1, siT2, siT3) at the optimal concentration were transfected into cultured astrocytes, and the most efficient siRNA was identified by the method of immunocytochemical staining and Western blotting. The proliferation of astrocytes tranfected with TREK-1-targeting siRNA under hypoxia condition was measured by fluorescence-activated cell sorting (FACS). The results showed that TREK-1 was expressed in cultured astrocytes. The dsRNA oligmers targeting TREK-1 could be transfected efficiently in cultured astrocytes and down-regulate the expression of TREK-1 in astrocytes. Moreover, the down-regulation of TREK-1 in astrocytes contributed to the proliferation of astrocytes under hypoxia condition as determined by cell cycle analysis. It was concluded that siRNA is a powerful technique that can be used to knockdown the expression of TREK-1 in astrocytes, which helps further investigate the function of TREK-1 channel in astrocytes under physicological and pathological condition.

Small RNA interference-mediated gene silencing of TREK-1 potassium channel in cultured astrocytes / 华中科技大学学报（医学）（英德文版）

This study was aimed to examine the effect of TREK-1 silencing on the function of astrocytes. Three 21-nucleotide small interfering RNA (siRNA) duplexes (siT1, siT2, siT3) targeting TREK-1 were constructed. Cy3-labeled dsRNA oligmers were used to determine the transfection efficiency in cultured astrocytes. TREK-1-specific siRNA duplexes (siT1, siT2, siT3) at the optimal concentration were transfected into cultured astrocytes, and the most efficient siRNA was identified by the method of immunocytochemical staining and Western blotting. The proliferation of astrocytes tranfected with TREK-1-targeting siRNA under hypoxia condition was measured by fluorescence-activated cell sorting (FACS). The results showed that TREK-1 was expressed in cultured astrocytes. The dsRNA oligmers targeting TREK-1 could be transfected efficiently in cultured astrocytes and down-regulate the expression of TREK-1 in astrocytes. Moreover, the down-regulation of TREK-1 in astrocytes contributed to the proliferation of astrocytes under hypoxia condition as determined by cell cycle analysis. It was concluded that siRNA is a powerful technique that can be used to knockdown the expression of TREK-1 in astrocytes, which helps further investigate the function of TREK-1 channel in astrocytes under physicological and pathological condition.

Capillary electrophoresis analysis of hydrogen peroxide induced apoptosis in PC12 cells.

Apoptosis is a highly regulated and controlled process of cell death that plays a fundamental role in many biological processes. Abnormal apoptosis of cells is closely related to some diseases such as cancer. Development of a simple and effective method to detect apoptosis is of great importance. In the present paper, capillary electrophoresis (CE) method was applied to distinguish cell apoptosis and necrosis of rat pheochromocytoma (PC12) cells treated by hydrogen peroxide by characterizing the DNA fragmentation. Firstly, effects of separation conditions (voltage, polymer concentration, temperature and injection time) on DNA separation were studied using 100 bp DNA ladders as the analyte. Under optimal separation condition (polyacrylamide coated capillaries: 57.5 cm x 75 microm i.d., effective length: 50 cm; running buffer: 1x TBE containing 2% PVP and 1.2% HEC; separation voltage: 5 kV; temperature: 25 degrees C; electrokinetic injection: 10 kV x 10 s), CE was used to monitor the progress of hydrogen peroxide induced apoptosis of PC12 cells by analyze DNA fragmentation. It was found that normal, apoptotic and neurotic cells had distinct DNA fragmentation patterns analyzed by CE. The results by CE were tested by other current methods (DAPI nuclei staining, flow cytometry analysis and TUNEL) to detect apoptosis and correlated well with those methods. Results show that CE can distinguish cell apoptosis and necrosis, quantify the degree of apoptosis in cells and have advantages of high efficiency, fast sample analysis speed, minute sample consumption and reliable results, which provides an accessorial method in the research of multiple diseases with abnormal apoptosis such as cancer and neurodegenerative diseases.

Nonlinear function retention model in weak acid anion chromatography.

A nonlinear function retention model for anion chromatography is developed, which is able to predict the retention behavior of polyvalent weak acid anions using sodium hydroxide as eluent. The relationship between the retention factors of phosphate and resorcinol and eluent concentration was studied with sodium hydroxide as the eluent. Both retention factors of the analyte anions first increase then decrease with the increase of sodium hydroxide concentration. The estimated values agree with the measured values with correlation coefficients for phosphate and resorcinol of 0.9920 and 0.9916, respectively, which shows the nonlinear function model is a useful addition to the theory of anion chromatography. The model is able to optimize the separation of polyvalent weak acid anions.

The dynamic changes of ATP content in rat cerebral cortex after transient ischemia followed by reperfusion / 临床神经病学杂志

Objective To investigate the dynamic changes of ATP content in rat cerebral cortex after transient ischemia followed by reperfusion and the relationship between the change of energy and the recovery of neural function.Methods The rats were subjected to 10 min of middle cerebral artery occlusion (MCAO). At the time point of 0 h, 1 h, 3 h, 6 h, 12 h, 24 h and 72 h after reperfusion, ATP contents of frontal and parietal cortex were measured by capillary zone electrophoresis.Results At the end of 10 min ischemia, ATP content fell dramatically to less than 20% of the control level. After reperfusion, ATP content recovered gradually. After 1 h, 3 h, 6 h and 12 h of reperfusion, ATP content returned to 70.5%, 65.7%, 84.8% and 86.9% of the control level ( P=0.052, 0.030, 0.332 and 0.491). From 24 h on until 72 h after reperfusion, ATP content decreased again, reaching half of the control level ( P=0.003 and P=0.023). After 10 min ischemia, limb function recovered gradually and completely at last. From 24 h on until 72 h after reperfusion, unwillingness of action and eating was found.Conclusions The recovery of cellular energy system function is delayed even though the reperfusion is in time after transient cerebral ischemia. Furthermore, secondary failure of cellular energy system function occurrs with the reperfusion proceeding. These phenomena are probably responsible for the delayed recovery of neural function after cerebral ischemia in spite of reperfusion.