miR-342-5p Regulates Neural Stem Cell Proliferation and Differentiation Downstream to Notch Signaling in Mice.

Notch signaling is critically involved in neural development, but the downstream effectors remain incompletely understood. In this study, we cultured neurospheres from Nestin-Cre-mediated conditional Rbp-j knockout (Rbp-j cKO) and control embryos and compared their miRNA expression profiles using microarray. Among differentially expressed miRNAs, miR-342-5p showed upregulated expression as Notch signaling was genetically or pharmaceutically interrupted. Consistently, the promoter of the miR-342-5p host gene, the Ena-vasodilator stimulated phosphoprotein-like (Evl), was negatively regulated by Notch signaling, probably through HES5. Transfection of miR-342-5p promoted the differentiation of neural stem cells (NSCs) into intermediate neural progenitors (INPs) in vitro and reduced the stemness of NSCs in vivo. Furthermore, miR-342-5p inhibited the differentiation of neural stem/intermediate progenitor cells into astrocytes, likely mediated by targeting GFAP directly. Our results indicated that miR-342-5p could function as a downstream effector of Notch signaling to regulate the differentiation of NSCs into INPs and astrocytes commitment.

Hif-1α and Hif-2α differentially regulate Notch signaling through competitive interaction with the intracellular domain of Notch receptors in glioma stem cells.

Hypoxia contributes to GSC expansion principally through Hif-1α and Hif-2α, but how these two factors work together has not been completely understood. We show that hypoxia promoted proliferation, self-renewal and inhibited the conversion of GSCs into INP-like cells through activating Notch signaling. Further data suggested that Hif-2α interacted with NICD and repressed the activity of Notch signaling, in contrast to the role of Hif-1α in Notch signaling. Together, our findings suggest that Hif-1α and Hif-2α competitively bind to NICD and dynamically regulate the activation of Notch signaling in GSCs likely depending on different oxygen tensions, providing improved therapeutic opportunities for malignant gliomas.

Osthole attenuates spinal cord ischemia-reperfusion injury through mitochondrial biogenesis-independent inhibition of mitochondrial dysfunction in rats.

BACKGROUND: Osthole, the main bioactive compounds isolated from the traditional Chinese medical herb broad Cnidium monnieri (L.) cusson, has been shown to exert spectrum of pharmacologic activities. The aim of this study was to investigate the potential neuroprotective effects of osthole against spinal cord ischemia-reperfusion injury in rats. MATERIALS AND METHODS: Osthole was administrated at the concentration of 0.1, 1, 10, 50, or 200 mg/kg (intraperitoneally) 1 h before spinal cord ischemia. The effects on spinal cord injury were measured by spinal cord water content, infarct volume, hematoxylin and eosin staining, and neurologic assessment. Mitochondria were purified from injured spinal cord tissue to determine mitochondrial function. RESULTS: We found that treatment with osthole (10 and 50 mg/kg) significantly decreased spinal cord water content and infarct volume, preserved normal motor neurons, and improved neurologic functions. These protective effects can be also observed even if the treatment was delayed to 4 h after reperfusion. Osthole treatment preserved mitochondrial membrane potential level, reduced reactive oxygen species production, increased adenosine triphosphate generation, and inhibited cytochrome c release in mitochondrial samples. Moreover, osthole increased mitochondria respiratory chain complex activities in spinal cord tissue, with no effect on mitochondrial DNA content and the expression of mitochondrial-specific transcription factors. CONCLUSIONS: All these findings demonstrate the neuroprotective effect of osthole in spinal cord ischemia-reperfusion injury model and suggest that oshtole-induced neuroprotection was mediated by mitochondrial biogenesis-independent inhibition of mitochondrial dysfunction.

The role of mitochondrial calcium uniporter in neuroprotection in traumatic brain injury.

The alteration in cellular Ca(2+) homeostasis is one of the key mechanisms contributing to secondary neuronal damage and altered physiology during the process of traumatic brain injury (TBI). However, there is considerable uncertainty about the efficacy of calcium channel blockers in randomized, controlled, clinical trials. In the physiological condition, cellular Ca(2+) homeostasis occurs through repetitive bursts of rising intracellular Ca(2+) that, sometimes are referred to as Ca(2+) oscillations. Mitochondria are intimately involved in the spatiotemporal tuning of cellular Ca(2+) signaling mainly through mitochondrial Ca(2+) uniporter (MCU). Excessive Ca(2+) uptake by the mitochondria through MCU is a key event in mitochondrial dysfunction and cell death in TBI. Selective inhibition of MCU has showed a promising cardioprotection and neuroprotection effect in many preclinical studies. Based on these preclinical results, the selective inhibition of MCU may be a new strategy for neuroprotection in TBI patients.

Notch signaling contributes to the maintenance of both normal neural stem cells and patient-derived glioma stem cells.

BACKGROUND: Cancer stem cells (CSCs) play an important role in the development and recurrence of malignant tumors including glioma. Notch signaling, an evolutionarily conserved pathway mediating direct cell-cell interaction, has been shown to regulate neural stem cells (NSCs) and glioma stem cells (GSCs) in normal neurogenesis and pathological carcinogenesis, respectively. However, how Notch signaling regulates the proliferation and differentiation of GSCs has not been well elucidated. METHODS: We isolated and cultivate human GSCs from glioma patient specimens. Then on parallel comparison with NSCs, we inhibited Notch signaling using γ-secretase inhibitors (GSI) and assessed the potential functions of Notch signaling in human GSCs. RESULTS: Similar to the GSI-treated NSCs, the number of the primary and secondary tumor spheres from GSI-treated GSCs decreased significantly, suggesting that the proliferation and self-renewal ability of GSI-treated GSCs were attenuated. GSI-treated GSCs showed increased differentiation into mature neural cell types in differentiation medium, similar to GSI-treated NSCs. Next, we found that GSI-treated tumor spheres were composed of more intermediate progenitors instead of CSCs, compared with the controls. Interestingly, although inhibition of Notch signaling decreased the ratio of proliferating NSCs in long term culture, we found that the ratio of G2+M phase-GSCs were almost undisturbed on GSI treatment within 72 h. CONCLUSIONS: These data indicate that like NSCs, Notch signaling maintains the patient-derived GSCs by promoting their self-renewal and inhibiting their differentiation, and support that Notch signal inhibitor GSI might be a prosperous candidate of the treatment targeting CSCs for gliomas, however, with GSI-resistance at the early stage of GSCs cell cycle.

Hemorrhagic pituitary macroadenoma: characteristics, endoscopic endonasal transsphenoidal surgery, and outcomes.

PURPOSE: This study aims to assess the effect of endoscopic endonasal transsphenoidal surgery (EETSS) of hemorrhagic pituitary macroadenoma (HPMA). PATIENTS AND METHODS: We retrospectively reviewed 52 cases with HPMA collected from the Xijing Hospital from April 1995 to April 2009. There were 39 males and 13 females, ranging in age from 18 to 79 years (average 51.6 years). Patients presented with headache or acute ophthalmological symptoms after adenoma hemorrhage. Computed tomography (CT) scan and magnetic resonance imaging (MRI) showed pituitary macroadenoma with hemorrhage in all cases. Twenty-eight adenomas showed marked suprasellar extension, 19 showed moderate extension, and another 5 showed slight extension. All patients were promptly treated by emergency EETSS, usually within 24 h after hospitalization. RESULTS: Total removal of tumor was achieved in 46 cases (88.5%), and subtotal removal in 6 cases (11.5%). Postoperative radiotherapy and reoperation of the tumor were required in five patients with either residual or relapsed tumors. Follow-up ranged from 8 to 93 months (mean 41.6 months) for 43 cases. Visual acuity and visual field recovery and improvement was recorded in 92.1% and 94.3% of patients who had preoperative visual symptoms, respectively. CONCLUSIONS: The majority of macroadenomas are hemorrhagic, and they often occur in middle-aged, male subjects. Detection by imaging in the setting of pituitary apoplexy accurately predicts the nature of the apoplectic process and helps to guide the type and timing of surgery. Early EETSS is the most effective therapy and significantly improves visual outcomes and systemic conditions.

[Minimally invasive neurosurgery for removal of pituitary adenomas by neuroendoscope aided with sellar floor reconstruction].

OBJECTIVE: To evaluate the effect of surgical technique and clinical curative effect for a unilateral endonasal-transsphenoidal approach in the removal of pituitary adenomas (PAs) by an endoscope-assisted technique with sellar floor reconstruction. METHODS: Between April 2001 and March 2009, 426 consecutive patients underwent extended neuroendoscopic unilateral endonasal transsphenoidal surgery. The series consisted of 54 (12.7%) as I type of Pas and 105 (24.6%) II type, 181(42.5%) III type and 86 (20.2%) IV type according to Hardy's classification criteria of pituitary adenoma. RESULTS: Tumor removal, as assessed by intraoperative findings and postoperative magnetic resonance imaging or CT scans, revealed complete tumor removal in 370 cases (86.9%) and subtotal tumor removal in 32 cases (7.5%) were achieved. Partial removal was carried out in the remaining 24 cases (5.6%) with fibrous tumor. Three patients (0.7%) had postoperative death in this group. Twenty-four patients (5.6%) had a postoperative cerebrospinal fluid leak that required repair operations. Six patients (1.4%) experienced a sphenoid mucositis and meningitis and they were cured by medical therapy. CONCLUSION: The slightly soft texture of PAs with or without a limited suprasellar extension and without involvement of vascular structures, may be resected through such an extended neuroendoscopic transsphenoidal approach. Intraoperative angled endoscope is a useful adjunct for safe removals.

Endoscopic endonasal transsphenoidal surgery for invasive pituitary adenoma.

Invasive pituitary adenomas (IPA) involving the skull base extend from the sella region, and invade surrounding structures. In the present study, we reviewed the therapeutic efficacy in a group of patients with IPA treated with endoscopic endonasal transsphenoidal surgery. Data from 78 IPA patients at our hospital were retrospectively reviewed. The diagnostic modalities, surgical techniques, and outcomes were reviewed. Diagnosis was confirmed by endocrinological profile and CT or MRI in all patients. Surgery was performed via an endoscopic endonasal transsphenoidal approach. Thirty-five patients (44.9%) had hormonally active tumors, and 43 (55.1%) had nonfunctioning tumors. Complete removal of the tumor was achieved in 62 patients (79.5%) and subtotal removal in 12 (15.4%); partial removal was achieved in the remaining four patients (5.1%) who had fibrous or dumbbell-shaped adenomas. The mean follow-up was 43.2 months in 65 patients and the clinical symptoms in all patients improved to varying degrees. In 52 patients, the tumors completely disappeared on follow-up imaging. Visual symptoms improved in 96.4% of the patients who had presented with visual impairment. These surgical results show that endoscopic endonasal transsphenoidal surgery for resection of IPA has advantages. We suggest that the endoscopic endonasal transsphenoidal surgery method is a safe, minimally invasive and efficient surgical technique for removal of IPA, providing good visualization of the operative field, generally complete tumor removal, short procedure duration, and minimal postoperative complications.

Emergency transsphenoidal surgery for hemorrhagic pituitary adenomas.

Hemorrhagic pituitary adenoma (HPA) is an acute clinical event in neurosurgery. Emergency surgical decompression is the most effective treatment. We retrospectively reviewed 65 cases collected from the Xijing Institute of Clinical Neuroscience from 1995 to 2005 with HPA. The majority of the patients (81.5%) experienced the acute symptoms of pituitary apoplexy including headache, ocular paresis, visual field deficits and hypopituitarism. On imaging features, 34 adenomas (52.3%) showed marked suprasellar extension, 17 (26.2%) showed moderate extension, and 6 (9.2%) had slight extension, another eight (12.3%) were intrasellar. All patients were treated promptly by emergency surgical decompression usually within 24h after the hospitalization. Twenty four patients operated on by the traditional transsphenoidal microsurgery; whereas 41 patients operated on by the endoscopic endonasal transsphenoidal surgery. Total removal of tumors was achieved in 59 cases (90.8%) and subtotal removal in 6 cases (9.2%). Postoperative radiotherapy, suppressive drug therapy and endocrine replacement therapy were required in seven patients with either remaining tumor or tumor recurrence. In a median follow-up period of 49 months for 54 cases, most patients' clinical symptoms had markedly improved. Visual acuity and visual fields improved in 88.4% and 92.7% of the patients who had preoperative visual symptoms, respectively. The majority of the HPA often occurred in patients with macroadenomas. With emergency surgical treatment, most patients with HPA could have quick improvement of symptoms, especially for altered consciousness and visual acuity or visual fields impairments.

[Inhibition of growth and angiogenesis of U251 cell xenograft in vivo by short hairpin RNA targeting survivin gene].

OBJECTIVE: To observe the impact of specific short hairpin RNA (shRNA) targeting survivin gene on tumorigenesis and angiogenesis of human brain glioblastoma U251 cells in vivo of nude mice. METHODS: U251 cells, U251-SR cells transfected stably with shRNA eukaryotic expression vector pWH1-SR targeting survivin gene, and U251-P cells transfected stably with blank pWH1 vector, were inoculated respectively into subcutaneous tissue in flank of 15 nude mice (each group 5 mice), and the tumor growth status was observed and measured. Protein expressions of survivin, proliferating cell nuclear antigen (PCNA) and factor VIII related antigen (F VIII RAg) were investigated by immunohistochemistry SABC method, apoptotic cells were screened by TUNEL method, furthermore proliferative index (PI), apoptotic index (AI) and microvessel density (MVD) were measured respectively in each group of tumor specimens. RESULTS: Comparing with those in U251 and U251-P groups, in U251-SR group, the tumorigenesis time delayed, tumor grew slowly, both tumor volume and tumor weight decreased significantly (P < 0.01 for both); Survivin protein expression was down-regulated markedly; PI and MVD decreased significantly, whereas AI increased remarkably (P < 0.01 for all). CONCLUSIONS: The specific shRNA targeting survivin gene can inhibit significantly tumorigenesis and angiogenesis of U251 cells in vivo.

[Endoscopic endonasal transsphenoidal approach for pituitary adenomas].

OBJECTIVE: To assess the clinical curative effect of the endonasal transsphenoidal approach for removing pituitary adenoma (PA) under neuroendoscope-assisted. METHODS: There were 215 patients who had undergone neuroendoscopic transsphenoidal surgery. Each patient received CT or MRI examination which showed the size and surrounding structural of tumor. RESULTS: Among the 215 patients, 190 cases (88.4%) had total removal, 17 cases (7.9%) achieved subtotal removal and the remaining 8 cases (3.7%) with fibrous tumor was carried out partial removal. Two patients (0.9%) died after operation. Postoperative follow-up period was 1 to 10 months (the average was 3.5 months). In 182 patients, 150 cases (90.9%) got vision recovered rapidly compared with their preoperative symptoms, such as diminished acuities and visual field defects, and 15 cases (9.1%) had gotten improvements to some extend among 165 who diagnosed as pituitary macroadenoma (PMaA); There were 17 patients who diagnosed as microadenoma (PMiA) showed that the pituitary dyshormonism recovered gradually. CONCLUSIONS: The endonasal transsphenoidal surgery under the neuroendoscope-assisted appears to be a safe, effective and micro-invasive method for PA.

Survivin expression and its relation with proliferation, apoptosis, and angiogenesis in brain gliomas.

BACKGROUND: An unbalance of cell proliferation and cell apoptosis is an important mechanism in carcinogenesis, and angiogenesis also plays a crucial role in tumorigenesis. Recently, survivin has been identified as an important member of the inhibitor of apoptosis protein (IAP) family. Although it has been shown that survivin is highly expressed in gliomas, and is associated with tumorigenesis, progression, and poor prognosis of gliomas, as yet the relation of survivin expression with proliferation, apoptosis, and angiogenesis of gliomas it is still unclear. METHODS: Eighty-three cases of brain glioma were chosen and protein expressions of survivin and proliferating cell nuclear antigen (PCNA) in glioma cells and Factor VIII-related antigen (FVIII-RAg) in vascular endothelial cells were investigated by immunohistochemistry. Apoptotic cells of brain glioma were screened by TdT-mediated dUTP nick end-labeling (TUNEL), and survivin immunoreactivity score (IRS), proliferative index (PI), apoptotic index (AI), overall daily growth (ODG), and microvessel density (MVD) in brain gliomas were measured. RESULTS: The survivin IRS, PI, AI, ODG, and MVD of brain gliomas were 3.75 +/- 3.89, 28.39 +/- 19.49%, 1.00 +/- 0.80%, 12.19 +/- 10.21%, and 62.75 +/- 31.50, respectively, and all of them increased markedly with an increase in the pathologic grade of brain gliomas (P < 0.001 for all). PI, ODG, and MVD in the survivin-positive group were significantly higher than those in the survivin-negative group (P < 0.001 for all). PI, ODG, and MVD were positively correlated with survivin IRS (P < 0.001 for all). Although there was no significant difference between AI in the survivin-positive group or in the survivin-negative group (P = 0.108), AI was inversely correlated with survivin IRS (P = 0.005). CONCLUSIONS: Survivin is overexpressed in brain gliomas, which may play an important role in malignant proliferation, antiapoptosis, and angiogenesis of brain gliomas.

[Neuroendoscope-assisted endonasal-transsphenoidal surgery for pituitary neoplasms].

OBJECTIVE: To evaluate the effect of curative effect of endonasal transsphenoidal approach for removal of pituitary neoplasms (PNs) assisted by neuroendoscopy. METHODS: Seventy-eight consecutive PNs patients with sellar mass causing compression of optic nerve and optic chiasm shown by MRI or CT underwent tumor removal via the endonasal transsphenoidal approach with the help of neuroendoscope. RESULTS: Total removal of tumor in 71 cases (91.0%) and subtotal removal in 5 cases (6.4%) were achieved. Partial removal was carried out in the remaining 2 cases (2.6%) with fibrous tumor. There was no postoperative death. Follow-up with a median of 3 months in 67 patients revealed that preoperative diminished acuity caused by optic nerve compression was recovered in 64 cases (95.5%), and improved in 3 cases (4.5%). Among the 62 patients with preoperative visual field defects, postoperative recovery was achieved in 60 cases (96.8%), and improvement in 2 cases (3.2%). CONCLUSION: Endonasal transsphenoidal approach assisted by neuroendoscopy is an effective minimally invasive method for removing the PNs. Changing the angle of the endoscope intraoperatively helps removing the tumor safely and completely.

[Research on relationship of survivin gene expression with malignant proliferation and apoptosis of brain glioma].

OBJECTIVE: To investigate the expression level of inhibitor of apoptosis protein survivin gene in human brain glioma and its role in malignant proliferation and antiapoptosis of brain glioma. METHODS: Eighty-three cases of brain glioma specimen was chosen, protein expression of survivin and proliferating cell nuclear antigen (PCNA) was investigated by immunohistochemistry streptavidin-biotin complex (SABC) method, the immunoreactivity score (IRS) of survivin and the proliferative index (PI) were counted. Apoptotic cells were screened by TdT-mediated dUTP-biotin nick-end labeling (TUNEL) method, and the apoptotic index (AI) of brain glioma was calculated. RESULTS: The survivin IRS, PI and AI of brain glioma were 3.8 +/- 3.9, (28.4 +/- 19.5)% and (1.0 +/- 0.8)% respectively, and all of them were elevated with the increase of pathological grade of brain glioma (P < 0.01 for all). PI in survivin positive group was significantly higher than that in survivin negative group (P < 0.01), and PI was positively correlated with survivin IRS (r = 0.740, P < 0.01). There was no significant difference between AI in survivin positive group and that in survivin negative group (P > 0.05), however, AI was negatively correlated with survivin IRS (r = -0.307, P < 0.01). CONCLUSIONS: Survivin is overexpressed in brain glioma, and which may play important roles in malignant proliferation and antiapoptosis of brain glioma.

Facial nerve function after excision of large acoustic neuromas via the suboccipital retrosigmoid approach.

We review our results for facial nerve preservation in 105 patients with large acoustic neuromas (diameter 4.0 cm or larger) undergoing excision via the suboccipital retrosigmoid approach. Microneurosurgical techniques and facial nerve monitoring were used. Complete tumor removal was achieved in 91 cases (86.7%) and subtotal removal in 14 (13.3%). There were two postoperative deaths (1.9%). The facial nerve was preserved anatomically in 83 (79.1%) patients. Using the House-Brackmann grading system, facial nerve function was assessed immediately after surgery, at the time of discharge and 1 year after surgery. Excellent function (Grades I and II) was present in 41.0%, 41.8%, and 56.7% of patients at each time interval, respectively, with acceptable function (Grade I-IV) in 78.5% (68/87 cases) at follow-up assessment at one year. The suboccipital retrosigmoid approach resulted in good anatomical and functional preservation of the facial nerve during excision of large acoustic neuromas, with minimal other morbidity and low mortality. We recommend this approach for excision of large acoustic neuromas.

Calcium overloading in traumatic axonal injury by lateral head rotation: a morphological evidence in rat model.

The study investigated morphologically axonal calcium overloading and its relationship with axonal structural changes. Twelve SD rats were divided into an injury and a sham group. The rat model of traumatic axonal injury (TAI) by lateral head rotation was produced. The oxalate-pyroantimonate technique for calcium localization was used to process the rat's medulla oblongata tissues with thin sections observed electron-microscopically for axonal structure and calcium precipitates on it. The axonal damage in medulla oblongata appeared at 2 h post-injury, gradually became diffuse and severe, and continued to exist at 24 hours. At 2 hours, calcium precipitates were deposited on separated lamellae and axolemma, but were rarely distributed in the axoplasm. At 6 hours, calcium precipitates occurred on separated lamellae and axolemma in much higher density, but on axoplasm in extremely small amounts. Some axons, though lacking structural changes of the myelin sheath, sequestered plenty of calcium deposits on their swollen mitochondria. At 24 hours, damaged axons presented with much more severe lamellae separation and calcium deposits. Axonal calcium overloading developed in rat TAI model using lateral head rotation. This was significantly related to structural damage in the axons. These findings suggest the feasibility of using calcium antagonists in cope the management of human DAI in its very early stage.

[Endovascular treatment of intracranial aneurysms with mechanical detachable spiral-neurological].

OBJECTIVE: To evaluate the efficacy of endovascular treatment of intracranial aneurysms with mechanical detachable spiral-neurological (MDS-N). METHODS: Thirty-six patients with intracranial aneurysms were treated with MDS-N by Seldinger's approaches through femoral artery puncture. A catheter was sent into the aneurysm with proper-size MDS-N system and a spiral was pushed into the aneurysmal lumen. RESULTS: The aneurysms were completely occluded in 32 cases while partial occlusion was obtained in 4 patients. The parent arteries remained unobstructed. Follow-up of 3 - 6 months showed that all patients recovered well. No death or permanent serious complication occurred. CONCLUSION: Simple, safe, and low-cost, treatment of intracranial aneurysm with MDS-N is effective and suitable for use in larger hospital.