Dexmedetomidine-Induced Contraction in the Isolated Endothelium-Denuded Rat Aorta Involves PKC-δ-mediated JNK Phosphorylation

Vasoconstriction mediated by the highly selective alpha-2 adrenoceptor agonist dexmedetomidine leads to transiently increased blood pressure and severe hypertension. The dexmedetomidine-induced contraction involves the protein kinase C (PKC)-mediated pathway. However, the main PKC isoform involved in the dexmedetomidine-induced contraction remains unknown. The goal of this in vitro study was to examine the specific PKC isoform that contributes to the dexmedetomidine-induced contraction in the isolated rat aorta. The endothelium-denuded rat aorta was suspended for isometric tension recording. Dexmedetomidine dose-response curves were generated in the presence or absence of the following inhibitors: the pan-PKC inhibitor, chelerythrine; the PKC-α and -β inhibitor, Go6976; the PKC-α inhibitor, safingol; the PKC-β inhibitor, ruboxistaurin; the PKC-δ inhibitor, rottlerin; the c-Jun NH₂-terminal kinase (JNK) inhibitor, SP600125; and the myosin light chain kinase inhibitor, ML-7 hydrochloride. Western blot analysis was used to examine the effect of rottlerin on dexmedetomidine-induced PKC-δ expression and JNK phosphorylation in rat aortic vascular smooth muscle cells (VSMCs) and to investigate the effect of dexmedetomidine on PKC-δ expression in VSMCs transfected with PKC-δ small interfering RNA (siRNA) or control siRNA. Chelerythrine as well as SP600125 and ML-7 hydrochloride attenuated the dexmedetomidine-induced contraction. Go6976, safingol, and ruboxistaurin had no effect on the dexmedetomidine-induced contraction, whereas rottlerin inhibited the dexmedetomidine-induced contraction. Dexmedetomidine induced PKC-δ expression, whereas rottlerin and PKC-δ siRNA transfection inhibited dexmedetomidine-induced PKC-δ expression. Dexmedetomidine also induced JNK phosphorylation, which was inhibited by rottlerin. Taken together, these results suggest that the dexmedetomidine-induced contraction involves PKC-δ-dependent JNK phosphorylation in the isolated rat aorta.     

ShcC proteins: Brain aging and beyond

To date, most studies of Shc family of signaling adaptor proteins have been focused on the near-ubiquitously expressed ShcA, indicating its relevance to age-related diseases and longevity. Although the role of the neuronal ShcC protein is much less investigated, accumulated evidence suggests its importance for neuroprotection against such aging-associated conditions as brain ischemia and oxidative stress. Here, we summarize more than decade of studies on the ShcC expression and function in normal brain, age-related brain pathologies and immune disorders with a focus on the interactions of ShcC with signaling proteins/pathways, and the possible implications of these interactions for changes associated with aging.     

腺病毒介导CNTF基因转染嗅鞘细胞移植对视神经损伤大鼠GAP-43表达影响

目的:通过检测大鼠视神经损伤后生长相关蛋白(GAP-43)的表达变化观察腺病毒介导睫状神经营养因子(ciliary neurotrophic factor,CNTF)基因转染的嗅鞘细胞(olfactory ensheathing cells,OECs)移植对颅内段视神经损伤后神经纤维长距离再生的促进作用.方法:建立额下显微外科入路大鼠颅内段视神经损伤动物模型并分组,构建腺病毒介导CNTF基因转染的嗅鞘细胞并移植入动物眼玻璃体内,检测GAP-43表达的积分光密度值.结果:成功培养分离出稳定分泌腺病毒介导CNTF基因的嗅鞘细胞,CNTF治疗组和OECs-CNTF治疗组GAP-43表达较损伤对照组显著增加(P<0.01), OECs(嗅鞘细胞)-CNTF组较单纯CNTF治疗组GAP-43表达明显增加,两组间差异明显(P<0.05).结论:腺病毒介导CNTF转染嗅鞘细胞移植对大鼠颅内段视神经损伤后神经纤维长距离再生具有明显的促进作用.     

Different methods for inducing adipose-derived stem cells to differentiate into Schwann-like cells

Introduction

The aim of the study was to explore an effective method to induce adipose-derived stem cells (ADSCs) to differentiate into Schwann-like cells in vitro.

Material and methods

Reagents were applied in two different ways (Dezawa inducing method and modified inducing method) in which inducers including β-mercaptoethanol (β-ME), all-trans-retinoic acid (ATRA), type I collagenase, forskolin, heregulin, basic fibroblast growth factor (BFGF) and brain-derived neurotrophic factor (BDNF) were used in different ways to induce ADSCs of rats to differentiate into Schwann-like cells. After induction, the cell morphologic characteristics and the cellular immunohistochemical staining positive rate of anti-S100 and anti-GFAP (glial fibrillary acidic protein) antibodies and the gray value of immunocytochemical dye with anti-S100 and anti-GFAP antibodies and cell activity measured by the MTT method were compared with each other to evaluate the induction effects.

Results

Both methods can induce differentiation of ADSCs of rats into Schwann-like cells, but the cellular morphology of the modified method was more similar to Schwann cells than that of the Dezawa inducing method, there was a higher cellular immunohistochemical staining positive rate and staining grey value in immunocytochemical dye with anti-S100 and anti-GFAP antibodies, and less damage in the cell activity of the modified inducing method than that of the Dezawa inducing method.

Conclusions

The effect of the modified method to induce ADSCs to differentiate into Schwann-like cells in vitro is superior to that of the Dezawa inducing method.     

糖尿病并发症相关基因醛糖还原酶酵母细胞模型的建立

目的 构建由绿色荧光蛋白（GFP）标记的糖尿病慢性并发症相关基因醛糖还原酶（AR）表达载体，并在酵母细胞中表达，建立AR抑制剂筛选模型。方法 构建AR与GFP的嵌合基因，将此AR：：GFP嵌合基因克隆到酵母表达载体pYEX-BX中，再将重组载体pYEX-BX-AR：：GFP转化至酵母宿主菌INVSC1，在SC-UD选择性培养基中表达AR：：GFP。结果 PCR扩增出约l106bp大小片段，为AR基因片段；RT-PCR在酵母细胞中检测到ARmRNA的表达；经CuS04诱导后可见AR：：GFP融合蛋白的绿色荧光；诱导剂CuSO4终浓度在100～200μmol／L范围内相对荧光强度较高，细胞密度适中；培养基SC-UD的pH值为6左右最适合细胞生长和荧光表达。结论 AR：：GFP在酿酒酵母中成功地表达，酵母细胞是研究目的基因功能与表达的良好模式菌。     

祛湿化瘀方通过调节AMPK活性改善高脂饮食诱导的实验性脂肪肝肝脏脂肪代谢

目的:研究祛湿化瘀方对高脂饮食诱导的大鼠脂肪肝AMPK蛋白活性及其相关脂肪代谢靶蛋白活性的影响,以探讨该方防治实验性脂肪肝的作用机制。方法:采用高脂饲料饮食诱导大鼠脂肪肝模型,造模大鼠给予高脂饮食4周后,按随机数字表随机分为模型组及祛湿化瘀方组,分别灌胃给予饮用水及中药祛湿化瘀方4周。实验8周末取材后观察:1)肝组织三酰甘油(Triglyceride,TG)、游离脂肪酸(Free Fatty Acid,FFA)含量,2)肝组织病理变化(HE染色、油红染色),3)肝组织腺苷酸活化的蛋白激酶(AMP-Activated K inase,AMPK)及磷酸化AMPK、肝组织总蛋白及核蛋白固醇调节元件结合蛋白-1c(Sterol Regulatory Element Binding Protein-1c、SREBP-1c)、肝组织总蛋白及核蛋白碳水化合物反应元件结合蛋白(Carbohydrate Response Element Binding Protein、ChREBP)含量、肝组织乙酰辅酶A羧化酶(Acety1 Co A Carboxylase,ACCase)及磷酸化ACC蛋白含量,4)肝组织AMPKα1、AMPKα2、SREBP-1、ACCα、SREBP-1c及ChREBP基因表达水平。结果:1)模型组肝组织TG、FFA含量显著升高,肝组织出现明显大泡样脂肪变性;模型组肝组织AMPK蛋白磷酸化水平降低、核蛋白SREBP-1与ChREBP表达增加、ACC蛋白磷酸化水平降低蛋白活性升高。2)祛湿化瘀方组肝组织TG、FFA含量较模型组显著降低,肝组织炎症及脂肪变性程度减轻;祛湿化瘀方能显著升高肝组织AMPK、ACC蛋白磷酸化水平、降低核蛋白SREBP-1及ChREBP含量。结论:祛湿化瘀方通过调节AMPK活性及其相关靶蛋白活性改善高脂饮食诱导的大鼠脂肪肝肝脂肪代谢,这可能是该方有效防治实验性脂肪肝的重要作用机制之一。     

白香丹胶囊对PMDD肝气逆证模型大鼠海马NMDAR1亚基蛋白分布及表达的影响

目的：以PMDD肝气逆证模型大鼠为载体,研究PMDD肝气逆证的病机以及白香丹胶囊对本病的干预机制。方法：改进情志刺激为主多因素分段刺激造模法,复制PMDD肝气逆证大鼠模型;用白香丹胶囊和氟西汀分散片予以干预,最后进行旷场实验评价模型;免疫荧光技术和蛋白印迹技术检测大鼠海马CA1、CA3区NMDAR1受体亚基分布情况及表达水平。结果：模型组大鼠与正常组相比较,其旷场实验的运动总距离明显增加（P<0.001）、中央区域的进入次数及停留在中央区域的时间显著减少（P<0.01）,海马CA1、CA3区细胞呈现稀疏杂乱的分布状态,且同氟西汀组一样,其NMDAR1蛋白表达量明显降低;白香丹组大鼠与模型组相比较,其旷场实验的运动总距离明显降低（P<0.05）、中央区域的进入次数和停留在中央区域的时间明显增多（P<0.05）,而氟西汀组与之相比,除了运动总距离明显降低（P<0.05）,其它指标不存在显著性差异,同氟西汀组一样,白香丹组大鼠海马CA1、CA3区细胞分布、排列无显著异常,但其NMDAR1蛋白表达量显著升高（P<0.0001）;氟西汀组大鼠与白香丹组相比较,其NMDAR1蛋白表达量明显降低（P<0.05）。结论：情志刺激为主多因素分段刺激造模法对大鼠学习记忆能力的损伤机制可能与大鼠海马CA1、CA3区神经细胞的减少和NMDAR1亚基的表达量降低有关,白香丹胶囊通过调整NMDAR1蛋白表达量纠正上述异常改变,从而改善大鼠的学习记忆能力。