MDH2 is an RNA binding protein involved in downregulation of sodium channel Scn1a expression under seizure condition.

Voltage-gated sodium channel α-subunit type I (NaV1.1, encoded by SCN1A gene) plays a critical role in the excitability of brain. Downregulation of SCN1A expression is associated with epilepsy, a common neurological disorder characterized by recurrent seizures. Here we reveal a novel role of malate dehydrogenase 2 (MDH2) in the posttranscriptional regulation of SCN1A expression under seizure condition. We identified that MDH2 was an RNA binding protein that could bind two of the four conserved regions in the 3' UTRs of SCN1A. We further showed that knockdown of MDH2 or inactivation of MDH2 activity in HEK-293 cells increased the reporter gene expression through the 3' UTR of SCN1A, and MDH2 overexpression decreased gene expression by affecting mRNA stability. In the hippocampus of seizure mice, the upregulation of MDH2 expression contributed to the decrease of the NaV1.1 levels at posttranscriptional level. In addition, we showed that the H2O2 levels increased in the hippocampus of the seizure mice, and H2O2 could promote the binding of MDH2 to the binding sites of Scn1a gene, whereas ß-mercaptoethanol decreased the binding capability, indicating an important effect of the seizure-induced oxidation on the MDH2-mediated downregulation of Scn1a expression. Taken together, these data suggest that MDH2, functioning as an RNA-binding protein, is involved in the posttranscriptional downregulation of SCN1A expression under seizure condition.

dl-3n-butylphthalide prevents stroke via improvement of cerebral microvessels in RHRSP.

The purpose of the study is to establish a model of cold-induced stroke in hypertensive rats, and to study the preventive effect of dl-3n-butylphthalide ( NBP ) on stroke. Stroke-prone renovascular hypertension(RHRSP) was created in Sprague-Dawley rats. The animals were assigned randomly to NBP, aspirin treated and vehicle control group, with administration of the medications for 7 days, and then subjected to cold treatment in an environmentally controlled chamber for 3 days to induce the occurrence of stroke. The incidence of stroke, the volume of the brain lesion, patency of the microvessels by FITC-dextran perfusion and the number of microvessels by immunohisochemical detection of vwF were investigated. Cold induced different types of stroke in RHRSP. The incidence of ischemic stroke and the volume of the infarct were decreased, and the perfused microvessels were increased with NBP pretreatment. Our data suggest that NBP prevents cold-induced ischemic stroke via improvement of cerebral microvessels.

Efficient gene transfection in the neurotypic cells by star-shaped polymer consisting of ß-cyclodextrin core and poly(amidoamine) dendron arms.

In order to develop the effective vectors that had high gene transfection capability and low cytotoxicity in the neuronal cells, we tested the star-shaped polymer consisting of ß-cyclodextrin core and poly(amidoamine) (PAMAM) dendron arms [ß-CD-(D3)7] as the vector to transfect the human neuroblastoma SH-SY5Y cells. The physicochemical properties of the ß-CD-(D3)7/plasmid DNA (pDNA) complexes were characterized by using gel electrophoresis, dynamic light scattering, transmission electron microscopy and zeta-potential experiments. Among the human neuroblastoma SH-SY5Y cells, ß-CD-(D3)7/pDNA complex demonstrated a lower toxicity compared to those of PAMAM (G=4, with an ethylenediamine core)/pDNA complex. When the N/P ratio was over 20, it was observed that PAMAM had a faster increment in toxicity compared to ß-CD-(D3)7. Fluorescent image, confocal microscopy image and flow cytometry showed that ß-CD-(D3)7/pDNA complexes had significantly higher transgene activity than that of PAMAM/pDNA complexes. For example, the transfection efficiency was 20% and 7.5% for ß-CD-(D3)7/pDNA and PAMAM/pDNA complexes, respectively. These results indicated that ß-CD-(D3)7 might be a promising candidate for neurotypic cells gene delivery with the characteristics of good biocompatibility, relatively high gene transfection capability and potential in vivo gene delivery ability.

[Changes in endothelial cellular adhesion molecule mRNA expressions in the cerebral blood vessels of rats with prestroke condition caused by simulated cold wave].

OBJECTIVE: To study the changes in the mRNA expression of endothelial cellular adhesion molecules in the cerebral blood vessels in rats with prestroke condition caused by simulated cold wave. METHODS: Two-kidney two-clip renovascular hypertension was induced in 48 male SD rats, which were subsequently randomly assigned into cold wave exposure and non-exposed group (n=24). Each group was further divided into 4 sub-groups according to their systolic blood pressure, namely the sham-operated group with blood pressure (BP)<140 mmHg, mild hypertensive group with BP of 160-199 mmHg, moderate hypertensive group with BP of 200-219 mmHg, and severe hypertensive group with BP no less than 220 mmHg. Cold wave exposure was simulated by housing the rats in an artificial climate chamber with 3 cycles of 12 h light at 22 degrees celsius; and 12 h dark at 4 degrees celsius;. The non-exposed group was kept at 22 degrees celsius; throughout the experiment. After the exposure, the rats were sacrificed and the tissues of the frontal lobe were slice into 2.0-mm-thick coronal sections for real-time RT-PCR detection of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and p-selectin mRNA expressions. The 5.0-microm-thick frozen sections from the bregma section underwent in situ hybridization of VCAM-1, ICAM-1, and p-selectin. The other sections were stained with HE to observe the infarct lesions, and the rats with cerebral infraction were excluded from the statistical analysis. RESULTS: In rats with cold wave exposure-induced prestroke condition and BP <220 mmHg, VCAM-1, ICAM-1, and p-selectin mRNA expressions all increased compared with those in the non-exposed group. In rats with BP>or=220 mmHg and cold exposure, the expressions all decreased to some extent compared with those in the non-exposed treatment. In the non-exposed rats, a positive correlation of BP to VCAM-1, ICAM-1, and p-selectin mRNA expressions were noted, and this correlation was also found in cold-wave-exposed rats with BP <220 mmHg; VCAM-1, ICAM-1, and p-selectin mRNA expressions decreased dramatically in the exposed rats with BP >or=220 mmHg compared with those in rats with BP <220 mmHg. CONCLUSION: Persistent and severe hypertension impairs the modulatory function of the cerebral vascular endothelia, which is a prerequisite for the stroke vulnerability. The modulatory function deteriorates as the BP further increases.