The Neuroprotective Roles of Sonic Hedgehog Signaling Pathway in Ischemic Stroke

Ischemic stroke is characterized by high morbidity, mortality and disability rate worldwide. Because of its complexity in pathogenesis and lack of effective therapeutic strategies and drugs, great breakthrough has not yet been made in the treatment of cerebral ischemic stroke. Therefore, to explore a more effective and safer therapeutic strategy for cerebral ischemic stroke has been the focus of numerous researchers. Neuroprotective effects of sonic hedgehog (Shh) signaling pathway in ischemic stroke have been reported in recent studies, but have not been fully elucidated. In our review, we elaborate the roles of Shh signaling in ischemic stroke from different aspects, including oxidative stress, excitotoxicity, neuroinflammation, apoptosis, angiogenesis, neuroplasticity, neurogenesis, astrogliosis and oligodendrogenesis. Meanwhile, Shh signaling based therapeutic approaches for cerebral ischemic stroke are also included in our review. We hope it will benefit the readers to better understand the roles of Shh signaling pathway in cerebral ischemic stroke and provide more comprehensive insights for basic research and novel strategies for the clinical treatment of cerebral ischemic stroke.     

能量代谢信号通路对缺血性脑卒中神经保护作用的研究进展

据近几年研究发现,能量代谢通路中的关键酶,如AMPK、Sirt1、PGC-1α、NAMPT,在控制缺血再灌注引起的钙离子超载、兴奋性氨基酸毒性、过氧化应激等损伤途径中发挥重要的作用,并且对缺血性神经起到保护作用。分别介绍这些能量代谢通路中的关键蛋白在缺血性神经保护中的作用机制,旨在为缺血性脑卒中的治疗提供新思路。     

Epistasis Analysis for Estrogen Metabolic and Signaling Pathway Genes on Young Ischemic Stroke Patients

Background

Endogenous estrogens play an important role in the overall cardiocirculatory system. However, there are no studies exploring the hormone metabolism and signaling pathway genes together on ischemic stroke, including sulfotransferase family 1E (SULT1E1), catechol-O-methyl-transferase (COMT), and estrogen receptor α (ESR1).

Methods

A case-control study was conducted on 305 young ischemic stroke subjects aged ≦ 50 years and 309 age-matched healthy controls. SULT1E1 -64G/A, COMT Val158Met, ESR1 c.454−397 T/C and c.454−351 A/G genes were genotyped and compared between cases and controls to identify single nucleotide polymorphisms associated with ischemic stroke susceptibility. Gene-gene interaction effects were analyzed using entropy-based multifactor dimensionality reduction (MDR), classification and regression tree (CART), and traditional multiple regression models.

Results

COMT Val158Met polymorphism showed a significant association with susceptibility of young ischemic stroke among females. There was a two-way interaction between SULT1E1 -64G/A and COMT Val158Met in both MDR and CART analysis. The logistic regression model also showed there was a significant interaction effect between SULT1E1 -64G/A and COMT Val158Met on ischemic stroke of the young (P for interaction = 0.0171). We further found that lower estradiol level could increase the risk of young ischemic stroke for those who carry either SULT1E1 or COMT risk genotypes, showing a significant interaction effect (P for interaction = 0.0174).

Conclusions

Our findings support that a significant epistasis effect exists among estrogen metabolic and signaling pathway genes and gene-environment interactions on young ischemic stroke subjects.     

缺血后处理对大鼠局灶性脑缺血再灌注损伤时TLR4 信号通路表达的影响

目的:观察缺血后处理对大鼠局灶性脑缺血再灌注损伤后TLR4通路表达的影响。方法:成年健康雄性SD大鼠110只,随机分为假手术组(sham组)(n=10)、缺血再灌注组(I/R组)和后处理组(IP组),后两组又依据缺血再灌注6h、12h、24h、48h、72h不同的时间点再分五个亚组。对各组行神经行为学评分,脑组织梗死体积测量,TUNEL技术检测神经细胞凋亡的情况,免疫组织化学技术观察各组大鼠脑组织TLR4、NF-κB和TNF-α蛋白的表达,原位杂交方法检测各组大鼠脑组织TLR4mRNA、NF-κBmRNA的表达。结果:缺血后处理可下调TLR4、NF-κB、TNF-α细胞炎性因子的表达,抑制细胞凋亡、减少脑梗死体积,改善神经行为。结论:后处理可通过抑制TLR4信号通路表达,减少脑梗死体积,改善神经功能。     

缺血后处理对大鼠局灶性脑缺血再灌注损伤时TLR4信号通路表达的影响

目的：观察缺血后处理对大鼠局灶性脑缺血再灌注损伤后TLR4通路表达的影响。方法：成年健康雄性SD大鼠110只,随机分为假手术组（sham组）（n=10）、缺血再灌注组（I／R组）和后处理组（IP组）,后两组又依据缺血再灌注6h、12h、24h、48h、72h不同的时间点再分五个亚组。对各组行神经行为学评分,脑组织梗死体积测量,TUNEL技术检测神经细胞凋亡的情况,免疫组织化学技术观察各组大鼠脑组织TLR4、NF—KB和TNF—a蛋白的表达,原位杂交方法检测各组大鼠脑组织TLR4mRNA、NF-KBmRNA的表达。结果：缺血后处理可下调TLR4、NF-KB、TNF-a细胞炎性因子的表达,抑制细胞凋亡、减少脑梗死体积,改善神经行为。结论：后处理可通过抑制TLR4信号通路表达,减少脑梗死体积,改善神经功能。     

Antidepressant Like Effect of Ascorbic Acid in Mice: Possible Involvement of NO-sGC-cGMP Signaling

The present study was designed to determine the antidepressant like activity of ascorbic acid (AA) in mice. Further the influence of NO-sGC-cGMP signaling in the antidepressant like effect of AA in mice was determined. Male swiss albino mice were used in the present study. Mice in the control group received saline and fluoxetine (10 mg/kg, i.p.) was used as the standard antidepressant drug. AA (50, 100 and 150 mg/kg, i.p.) was administered to the mice and depression related behavior were determined using tail suspension test (TST) and forced swim test (FST). Further the whole brain nitrite and serotonin levels were also determined. It was observed that the administration of AA (100 mg/kg, i.p.) reversed the depression like behavior in mice in TST and FST. AA (100 mg/kg, i.p.) treatment decreased the level of nitrite and increased the level of serotonin in the brain of mice significantly as compared to control. Further the behavioral and neurochemical effect of AA (50 mg/kg, i.p) was studied in NO modulator [NO donor: L-Arginine (50 mg/kg, i.p); NO-sGC inhibitor: methylene blue (1 mg/kg, i.p.) and cGMP modulator: sildenafil (1 mg/kg, i.p.)] pretreated mice. It was observed that the pretreatment of NO donor and cGMP modulator counteracted the effect conferred by AA (50 mg/kg, i.p). While the pretreatment of NO-sGC inhibitor potentiated the effect conferred by AA (50 mg/kg, i.p). The present study suggested that the AA confer antidepressant like effect in mice and NO-sGC-cGMP signaling pathway influence the antidepressant like effect of AA in mice.

     

Proteomic Identification of DNA-PK Involvement within the RET Signaling Pathway

Constitutive activation of the Rearranged during Transfection (RET) proto-oncogene leads to the development of MEN2A medullary thyroid cancer (MTC). The relatively clear genotype/phenotype relationship seen with RET mutations and the development of MEN2A is unusual in the fact that a single gene activity can drive the progression towards metastatic disease. Despite knowing the oncogene responsible for MEN2A, MTC, like most tumors of neural crest origin, remains largely resistant to chemotherapy. Constitutive activation of RET in a SK-N-MC cell line model reduces cell sensitivity to chemotherapy. In an attempt to identify components of the machinery responsible for the observed RET induced chemoresistance, we performed a proteomic screen of histones and associated proteins in cells with a constitutively active RET signaling pathway. The proteomic approach identified DNA-PKcs, a DNA damage response protein, as a target of the RET signaling pathway. Active DNA-PKcs, which is phosphorylated at site serine 2056 and localized to chromatin, was elevated within our model. Treatment with the RET inhibitor RPI-1 significantly reduced s2056 phosphorylation in RET cells as well as in a human medullary thyroid cancer cell line. Additionally, inhibition of DNA-PKcs activity diminished the chemoresistance observed in both cell lines. Importantly, we show that activated DNA-PKcs is elevated in medullary thyroid tumor samples and that expression correlates with expression of RET in thyroid tumors. These results highlight one mechanism by which RET signaling likely primes cells for rapid response to DNA damage and suggests DNA-PKcs as an additional target in MTC.     

Resveratrol Pretreatment Decreases Ischemic Injury and Improves Neurological Function Via Sonic Hedgehog Signaling After Stroke in Rats

Resveratrol has neuroprotective effects for ischemic cerebral stroke. However, its neuroprotective mechanism for stroke is less well understood. Beneficial actions of the activated Sonic hedgehog (Shh) signaling pathway in stroke, such as improving neurological function, promoting neurogenesis, anti-oxidative, anti-apoptotic, and pro-angiogenic effects, have been noted, but relatively little is known about the role of Shh signaling in resveratrol-reduced cerebral ischemic injury after stroke. The present study tests whether the Shh pathway mediates resveratrol to decrease cerebral ischemic injury and improve neurological function after stroke. We observed that resveratrol pretreatment significantly improved neurological function, decreased infarct volume, enhanced vitality, and reduced apoptosis of neurons in vivo and vitro after stroke. Meanwhile, expression levels of Shh, Ptc-1, Smo, and Gli-1 mRNAs were significantly upregulated and Gli-1 was relocated to the nucleus. Intriguingly, in vivo and in vitro inhibition of the Shh signaling pathway with cyclopamine, a Smo inhibitor, completely reversed the above effects of resveratrol. These results suggest that decreased cerebral ischemic injury and improved neurological function by resveratrol may be mediated by the Shh signaling pathway.     

Cardioembolism and Involvement of the Insular Cortex in Patients with Ischemic Stroke

BackgroundTo evaluate whether topographical characteristics of insular involvement in ischemic stroke are associated with cardioembolism.ConclusionsIn cases of stroke in the MCA territory, involvement of the insular cortex may be associated with a risk of cardioembolism.     

RISK and SAFE Signaling Pathway Involvement in Apolipoprotein A-I-Induced Cardioprotection

Recent findings indicate that apolipoprotein A-I (ApoA-I) may be a protective humoral mediator involved in remote ischemic preconditioning (RIPC). This study sought to determine if ApoA-I mediates its protective effects via the RISK and SAFE signaling pathways implicated in RIPC. Wistar rats were allocated to one of the following groups. Control: rats were subjected to myocardial ischemia/reperfusion (I/R) without any further intervention; RIPC: four cycles of limb I/R were applied prior to myocardial ischemia; ApoA-I: 10 mg/Kg of ApoA-I were intravenously injected prior to myocardial ischemia; ApoA-I + inhibitor: pharmacological inhibitors of RISK/SAFE pro-survival kinase (Akt, ERK1/2 and STAT-3) were administered prior to ApoA-I injection. Infarct size was significantly reduced in the RIPC group compared to Control. Similarly, ApoA-I injection efficiently protected the heart, recapitulating RIPC-induced cardioprotection. The ApoA-I protective effect was associated with Akt and GSK-3β phosphorylation and substantially inhibited by pretreatment with Akt and ERK1/2 inhibitors. Pretreatment with ApoA-I in a rat model of I/R recapitulates RIPC-induced cardioprotection and shares some similar molecular mechanisms with those of RIPC-involved protection of the heart.     

急性缺血性脑卒中临床路径管理模式的优化及实践

目的 评价优化后急性缺血性脑卒中临床路径管理模式的优越性。方法 随机选取医院实施急性缺血性脑卒中治疗临床路径管理优化前后收治的急性脑梗死患者各200例,采用回顾性分析比较各组患者的相关指标。结果 路径优化管理后,患者诊疗等待时间缩短,疾病规范诊疗比率进一步提高,医护工作量大大减少,患者满意度进一步提高。结论 实施临床路径能够改善医疗质量,更好地利用医疗资源。临床路径优化后医疗质量进一步提高。     

PLC—IP3信号途径参与花粉管伸长调控的显微注射实验

以百合（Ｌｉｌｉｕｍ ｄａｖｉｄｉｉ Ｄｕｃｈ．）花粉为材料,通过显微注射肌醇磷脂信使系统中重要组成成分或其抗体,研究该信使系统牟花粉管伸长的影响。发现显微注射动物来源磷脂酶Ｃ（ＰＬＣ）β１－３抗体显著抑制花粉管的伸长生长,而注射ＰＬＣβ４抗体对花粉管伸长无影响;显微注射三磷酸肌醇（ＩＰ３）,可显著促进花粉管伸长生长;显微注射动物来源的ＩＰ３Ｒ２、ＩＰ３Ｒ３抗体可显著抑制花粉管伸长生长,而注射ＩＰ     

The Involvement of PLC-IP3 Signaling Pathway in Pollen Tube Growth

The effect of phospholipase C (PLC) signaling pathway on lily (Lilium davidii Duch.) pollen tube elongation was examined by means of microinjection. Pollen tube elongation was inhibited by microinjecting antibodies against animal PLCβ1-3 or inositol-1,4,5-triphosphate receptor （IP3R2, 3）, but was not affected by antibodies against animal PLCβ4 or IP3R1. Pollen tube elongation was also stimulated significantly by microinjecting IP3. The results suggest that PLC-IP3 signaling pathway might present in pollen system and be involved in pollen tube growth.     

The Role of Tryptophan Catabolism along the Kynurenine Pathway in Acute Ischemic Stroke

Post-stroke inflammation may induce upregulation of the kynurenine (KYN) pathway for tryptophan (TRP) oxidation, resulting in neuroprotective (kynurenic acid, KA) and neurotoxic metabolites (3-hydroxyanthranillic acid, 3-HAA). We investigated whether activity of the kynurenine pathway in acute ischemic stroke is related to initial stroke severity, long-term stroke outcome and the ischemia-induced inflammatory response. Plasma concentrations of TRP and its metabolites were measured in 149 stroke patients at admission, at 24 h, at 72 h and at day 7 after stroke onset. We evaluated the relation between the KYN/TRP ratio, the KA/3-HAA ratio and stroke severity, outcome and inflammatory parameters (C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and neutrophil/lymphocyte ratio (NLR)). KYN/TRP but not KA/3-HAA correlated with the NIHSS score and with the infarct volume. Patients with poor outcome had higher mean KYN/TRP ratios than patients with more favourable outcome. The KYN/TRP ratio at admission correlated with CRP levels, ESR and NLR. The activity of the kynurenine pathway for tryptophan degradation in acute ischemic stroke correlates with stroke severity and long-term stroke outcome. Tryptophan oxidation is related to the stroke-induced inflammatory response.     

Proteomic Analysis of Differential Proteins Related to Anti-nociceptive Effect of Electroacupuncture in the Hypothalamus Following Neuropathic Pain in Rats

Increasing evidence has been accumulated for the effectiveness of acupuncture therapy in relieving pain. However, there are limited data on regulation of protein expression after electroacupuncture (EA) intervention. Thus, the present study is designed to determine changes in protein expression following EA stimulation in rats with sciatic nerve chronic constrictive injury (CCI) induced neuropathic pain. Sixty Wistar rats were equally randomized into normal control group, CCI group, and CCI with EA stimulation (EA) group. The CCI model was established by ligature of the left sciatic nerve. EA stimulation was applied at Zusanli (ST36) and Yanglingquan (GB34) in the EA group. Differentially expressed hypothalamic proteins in the three groups were identified by 2-D gel electrophoresis and matrix-assisted laser desorption/ionization time of flight mass spectrometry. The functional clustering and pathway of the identified proteins were analyzed by Mascot software. Results showed that, after CCI, the thermal pain threshold of the affected hind footpad was decreased and was reversed gradually by 12 sessions of EA treatment. Following EA intervention, there were 17 hypothalamic proteins identified with significant changes in the expression (>twofold). Three gene-ontologies (oxidoreductase activity, oxidation reduction, and protein binding) were enriched, while there was a significant regulation of glycolysis/gluconeogenesis/hexose metabolism pathway. These data demonstrate that EA intervention can attenuate pain via regulation of expression of multiple proteins in the hypothalamus. Further, hypothalamic glucose metabolism may be important in supporting energy and neurotransmitter homeostasis in the effects of EA intervention.     

Docosahexaenoic Acid Signaling Modulates Cell Survival in Experimental Ischemic Stroke Penumbra and Initiates Long-Term Repair in Young and Aged Rats

Background

Docosahexaenoic acid, a major omega-3 essential fatty acid family member, improves behavioral deficit and reduces infarct volume and edema after experimental focal cerebral ischemia. We hypothesize that DHA elicits neuroprotection by inducing AKT/p70S6K phosphorylation, which in turn leads to cell survival and protects against ischemic stroke in young and aged rats.

Methods and Results

Rats underwent 2 h of middle cerebral artery occlusion (MCAo). DHA, neuroprotectin D1 (NPD1) or vehicle (saline) was administered 3 h after onset of stroke. Neurological function was evaluated on days 1, 2, 3, and 7. DHA treatment improved functional recovery and reduced cortical, subcortical and total infarct volumes 7 days after stroke. DHA also reduced microglia infiltration and increased the number of astrocytes and neurons when compared to vehicle on days 1 and 7. Increases in p473 AKT and p308 AKT phosphorylation/activation were observed in animals treated with DHA 4 h after MCAo. Activation of other members of the AKT signaling pathway were also observed in DHA treated animals including increases in pS6 at 4 h and pGSK at 24 h. DHA or NPD1 remarkably reduced total and cortical infarct in aged rats. Moreover, we show that in young and aged rats DHA treatment after MCAo potentiates NPD1 biosynthesis. The phosphorylation of p308 AKT or pGSK was not different between groups in aged rats. However, pS6 expression was increased with DHA or NPD1 treatment when compared to vehicle.

Conclusions

We suggest that DHA induces cell survival, modulates the neuroinflammatory response and triggers long term restoration of synaptic circuits. Both DHA and NPD1 elicited remarkable protection in aged animals. Accordingly, activation of DHA signaling might provide benefits in the management of ischemic stroke both acutely as well as long term to limit ensuing disabilities.     

Electroacupuncture Promotes Autophagy by Regulating the AKT/mTOR Signaling Pathway in Temporal Lobe Epilepsy

Neurochemical Research - Temporal lobe epilepsy (TLE) is a complex neurological disease, and its occurrence and development are closely related to the autophagy signaling pathway. However, the...     

应用手持激光器建立光化学法脑梗死动物模型

目的应用手持激光器作为光源建立光化学法局灶性脑梗死动物模型。方法将36只SD大鼠随机分为4组,即A组：开骨窗至硬脑膜,不注射玫瑰红,手持激光器照射5rain;B组：开骨窗至硬脑膜,注射玫瑰红,手持激光器照射5min;C组：保留颅骨内板,注射玫瑰红,手持激光器照射5min;D组：开骨窗至硬脑膜,注射玫瑰红,冷光源照射40rain。于术后24、48h对各组大鼠进行神经功能的行为学评分,进行MR扫描,术后48h处死动物,TTC染色测量梗死体积,光镜下观察病理改变,比较各组的模型制作成功率。结果不同方法进行动物模型制作时,24h神经功能的行为学评分有显著性差异,48h后差异消失。头部MR扫描显示,A组未见脑梗死形成,B组、c组全部有脑梗死灶形成,D组仅部分大鼠形成梗死灶,但体积明显较B、C组小,另外C组有2例合并硬膜外血肿。TTC染色A组未见梗死灶形成,B组、C组可见恒定的梗死灶,D组仅部分形成梗死灶。B、C、D组模型制作成功率分别为100％、80％、50％,将B组、C组合并为手持激光器组,与冷光源组（D组）比较,两种方法间有显著性差异（P=0．026）。结论应用手持激光器作为照射光源与冷光源相比,有更高的模型制作成功率。     

Low Density Lipoprotein Receptor-related Protein 1 Promotes Anti-apoptotic Signaling in Neurons by Activating Akt Survival Pathway

The low density lipoprotein receptor-related protein 1 (LRP1) is a multi-ligand receptor abundantly expressed in neurons. Previous work has shown that brain LRP1 levels are decreased during aging and in Alzheimer disease. Although mounting evidence has demonstrated a role for LRP1 in the metabolism of apolipoprotein E/lipoprotein and amyloid-β peptide, whether LRP1 also plays a direct role in neuronal survival is not clear. Here, we show that LRP1 expression is critical for the survival of primary neurons under stress conditions including trophic withdrawal, the presence of apoptosis inducers, or amyloid-β-induced neurotoxicity. Using lentiviral short hairpin RNA to knock down endogenous LRP1 expression, we showed that a depletion of LRP1 leads to an activation of caspase-3 and increased neuronal apoptosis, an effect that was rescued by a caspase-3 inhibitor. A correlation between decreased Akt phosphorylation and the activation of caspase-3 was demonstrated in LRP1 knocked down neurons. Notably, LRP1 knockdown decreased insulin receptor levels in primary neurons, suggesting that decreased neuronal survival might be a consequence of an impaired insulin receptor signaling pathway. Correspondingly, both insulin receptor and phospho-Akt levels were decreased in LRP1 forebrain knock-out mice. These results demonstrate that LRP1 mediates anti-apoptotic function in neurons by regulating insulin receptor and the Akt survival pathway and suggest that restoring LRP1 expression in Alzheimer disease brain might be beneficial to inhibiting neurodegeneration.