脾非淋巴细胞条件培养液作用于颈上节的实验观察

探讨脾非淋巴细胞是否能够产生具有生物活性的神经营养因子。分离ＢＡＬＢ／ｃ小鼠非淋巴细胞并进行原代培养,收集培养上清液作为条件培养液孵育新生小鼠颈上节６０ｈ。结果显示,对对照培养液相比,条件培养液能够地促进体外培养中颈上节交感神经生长的发育,且这一作用在不同程度上可被抗ＮＧＦ和ＮＴ－３抗体特异性阻断。免疫组化染色证实培养的脾非淋巴细胞中抗神经生长因子（ＮＦＧ）和神经营养素－３（ＮＴ－３）免疫反应产物     

人脑胶质瘤尿激酶型纤溶酶原激活因子基因表达及意义

目的 探讨尿激酶型纤溶酶原激活因子（ｕＰＡ）基因在人脑胶质瘤中的表达及临床意义。方法 采用Ｎｏｒｔｈｅｒｎ印迹分子杂交和免疫组方法检测４３例人脑胶质瘤和５例正常脑组织ｕＰＡ ｍＲＮＡ的蛋白表达,并与临床床生物学参数进行综合分析。结果 上述组织或细胞均可表达２．５Ｋｂ的ｕＰＡ ｍＲＮＡ转录物,高级另胶质瘤较低级别和正常脑组织ｕＰＡ ｍＲＮＡ表达水平明显增高（Ｐ〈０．０１）,低级别胶质瘤与正常脑组织的     

青霉素对体外培养鼠脑γ－氨基丁酸能神经元及胶质细胞的影响

以免疫细胞化学方法观察了分离培养４天、１０天鼠大脑皮层、海马ＧＡＢＡ能神经元以及ＧＦＡＰ免疫反应阳性星形胶质细胞对大剂量致痫剂青霉素（Ｐｅｎｉｃｉｌｉｎ，ＰＥＮ）的反应。结果大剂量ＰＥＮ（３００μ／ｍｌ培养液）可引起培养海马及皮层γ－氨基丁酸（γ－ａｍｉｎｏｂｕｔｙｒｉｃａｃｉｄ，ＧＡＢＡ）能神经元数目明显减少，星形胶质细胞显著增生，且尤以海马胶质细胞增生明显。提示：（１）脑内尤其海马区星形胶质细胞增生与癫痫发生、发展有一定的关系；（２）传统致痫剂ＰＥＮ可能是通过抑制ＧＡＢＡ能神经元功能、刺激星形胶质细胞增生，从而导致癫痫发作     

延髓呼吸中枢损伤后神经营养因子基因表达特点的免疫组化研究

目的为临床应用神经营养因子（ｎｅｕｒｏｔｒｏｐｈｉｃｆａｃｔｏｒｓ,ＮＴＦｓ）疗法治疗脑干呼吸中枢损伤提供理论和实验研究基础。方法实验动物采用ＳＤ大鼠,以直流电解损毁法建立一侧延髓呼吸中枢损伤动物模型,采用免疫组化染色法对损伤后不同时间点ＮＴＦｓ基因的表达特点进行了研究。结果神经营养素－３（ｎｅｕｒｏｔｒｏｐｈｉｎ－３,ＮＴ－３）和神经生长因子（ｎｅｒｖｅｇｒｏｗｔｈｆａｃｔｏｒ,ＮＧＦ）的表达最为活跃,脑源性神经营养因子（ｂｒａｉｎ－ｄｅｒｉｖｅｄｎｅｕｒｏｔｒｏｐｈｉｃｆａｃｔｏｒ,ＢＤＮＦ）和成纤维细胞生长因子（ｆｉｂｒｏｂｌａｓｔｇｒｏｗｔｈｆａｃｔｏｒ,ＦＧＦ）也有一定表达。结论在延髓呼吸中枢的局灶性损伤后,ＮＴ－３、ＮＧＦ、ＢＤＮＦ和ＦＧＦ可能在延髓呼吸神经元受损后的自我保护及修复中发挥了活跃的作用     

GFP,TH双基因在NIH-3T3细胞及帕金森病大鼠脑内的表达

目的以绿色荧光蛋白（ＧＦＰ）作为一个标记,观察ＧＦＰ标记的ＨＴＨ１基因修饰的ＮＩＨ－３Ｔ３细胞在体外及植入脑内后的生长情况,判断ＧＦＰ基因能否作为一种新的筛选标记基因。方法构建同时表达ＧＦＰ和ＨＴＨ１双基因的多基因表达载体ＧＣ－ＧＦＰ－Ｐ－ＨＴＨ１－ＳＮ。并转染ＮＩＨ－３Ｔ３细胞,且移植入Ｐａｒｋｉｎｓｏｎ病模型大鼠纹状体内。结果用荧光显微镜、流式细胞仪、免疫组化、ｗｅｓｔｅｒｎｂｌｏｔｉｎｇ等方法均检测到ＧＦＰ、ＨＴＨ１在体外和脑内的表达。结论ＧＦＰ可作为一个筛选标记基因,可对目的基因或植入细胞的其他功能性产物的表达进行观察和检测。     

急性脑梗死患者血浆纤溶酶原激活剂抑制物活性及其启动子区 …

目的 探讨纤溶酶原激活剂抑制物（ＰＡＩ－１）活性和启动子基因多态性在急性脑梗死发病过程中的作用。方法 通过等位基因特异性寡核苷酸斑点要交技术，测定１０７例急性脑梗死患者和９５名健康人的白细胞ＰＡＩ－１启动子区４Ｇ／５Ｇ多态性位点的基因型，用发色底物法测定血浆ＰＡＩ－１活性。结果 脑梗死组血浆ＰＡＩ－１活性明显高于对照组，病例组和组织中４Ｇ／４Ｇ基因型患者的ＰＡＩ－１活性水平最高，４Ｇ／５Ｇ基因型次     

人脑胶质瘤免疫抑制因子研究

实验表明人脑胶质瘤原代培养细胞及４个人脑恶性胶质瘤体外细胞系细胞培养上清液（Ｓｕ－ｐｅｒｎａｔａｎｔ，ＳＮ）显著抑制植物血凝素ＰＨＡ－Ｐ刺激的正常人或胶质瘤患者自体和异体外周血淋巴细胞增殖。我们发现用抗转化生长因子－β_２（ＴＧＦ－β_２）单克隆抗体可显著降低胶质瘤ＳＮ的免疫抑制活性。４个人脑胶质瘤体外细胞系应用抗ＴＧＦ－β_２单抗免疫组化染色呈阳性反应，３例正常脑组织呈阴性反应。Ｎｏｒｔｈｅｒｎ杂交实验表明上述４个人脑胶质瘤体外细胞系均表达６ｋｂ的ＴＧＦ－β_２ｍＲＮＡ，而４例人胎脑则无表达。这些结果提示人脑胶质瘤细胞可以自体分泌免疫抑制因子抑制患者的免疫功能，而这抑制因子的主要成份是ＴＧＦ－β_２。     

青霉素对体外培养鼠脑γ—氨基丁酸能神经元及胶质细胞的影响

经免疫细胞化学方法观察了分离培养４天，、１０天鼠大脑皮层、海马ＧＡＢＡ能神经元以及ＧＦＡＰ免疫反应阳性星形胶质细胞对大剂量致痫剂青霉素的反应。结果大剂量ＰＥＮ可引起培养海马及皮层γ－氨基丁酸能神经元数目明显减少，星形胶质细胞显著增生，且尤以海马胶质细胞增生明显。提示：（１）脑内尤其海马区星形胶南细胞增生与癫痫发生，发展有一定的关系。（２）传统致痫剂ＰＥＮ可能是通过抑制ＧＡＢＡ能神经元功能、刺激星形     

Alzheimer病的病理与临床诊断

对生前经过痴呆调查与临床诊断的９例老人院住院老人死亡后进行尸解神经病理学观察。结果发现９例尸检脑均有不同程度的萎缩与锥全细胞减少，脂褐素沉积，胶质细胞增生，淀粉样小体存在。其中３例尚在皮层与海在量老年斑（ＳＰｓ）与神经原纤维缠结（ＮＴＦｓ），病理确诊为Ａｌａｈｅｉｍｅｒ病（ＡＤ）；其余６例明确为非Ａｌｚｈｅｉｍｅｒ病老年脑（ＮＡＤ）。该病理结果与临床诊断全部痊愈，提示ＮＩＮＣＤＳ－ＡＤＲＤＡ之ＡＤ     

体外培养大鼠星形胶质细胞受损后的激活与反应性胶质化

用鼠脑星形胶质细胞（ＡＳ）原代培养技术建立体外ＡＳ机械性损伤模型。以ｃ—Ｆｏｘｓ、ｂＦＧＦ、ＰＣＮＡ、ＧＦＡＰ—ｍＲＮＡ、ＧＦＡＰ和Ｍｙｏｓｉｎ作为观察指标研究反应性星形胶质化的形成机制。结果显示：１．ｃ—Ｆｏｓ蛋白于损伤后４５ｍｉｎ即有阳性表达，伤后２ｈ消失；２．损伤后２ｈ，损伤边缘的ＡＳ开始表达ｂＦＧＦ，１２ｈ达高峰，２ｄ后表达强度开始回落；３．损伤边缘的部分ＡＳ于损伤后２ｈ开始表达ＰＣＮＡ，伤后１ｄ，ＰＣＮＡ阳性的ＡＳ沿损伤边缘呈列兵式整齐排列，２ｄ后ＰＣＮＡ阳性的ＡＳ分布于损伤周围区域；４．损伤后４ｈ，损伤边缘的ＡＳ开始表达Ｍｙｏｓｉｎ，并逐渐增加，而且朝向损伤区胞浆突起的阳性表达强于背向损伤区的突起；５．损伤边缘的ＡＳ于损伤后６ｈ开始表达ＧＦＡＰ—ｍＲＮＡ，１ｄ达高峰，２ｄ开始回落，３ｄ则只在少数ＡＳ中可检出ＧＦＡＰ—ｍＲＮＡ；６．损伤后１ｄ，ＧＦＡＰ表达明显增强，胞体肥大并向损伤区伸出粗大突起，２ｄＧＦＡＰ达高峰，３ｄ肥大ＡＳ的胞体和突起覆盖损伤区；７．在体外ＡＳ机械性损伤模型上，在没有神经元和其它复杂因素影响的条件下，ＡＳ对损伤的主要反应是胞体的肥大、突起的粗大，并能独立形成反应性星形胶质化。     

Ceramide-enhanced urokinase-type plasminogen activator (uPA) release is mediated by protein kinase C in cultured microglia

As described previously, a relatively high dose of neurotrophins increased the release of urokinase-type plasminogen activator (uPA) from cultured microglia. This biological response is suggested to be caused by ceramide, which is a metabolite of nerve growth factor low-affinity receptor (NGFRp75)-associated sphingomyelin turnover. Therefore, in the present study, we examined the effect of ceramide on the release of uPA from cultured microglia. Treatment of the cells with permeable C8-ceramide (D-erythro-Sphingosine, N-octanoyl-) enhanced uPA release in a dose-dependent manner. This effect of C8-ceramide was mimicked by treatment with bacterial sphingomyelinase. A pharmacological study using a specific PKC activator, phorbol-12-myristate-13-acetate, and a protein kinase C (PKC) inhibitor, bisindolylmaleimide, showed that PKC activation is required in order to release uPA from ceramide-stimulated microglia as well as from nonstimulated microglia. Further study using a specific conventional PKC (cPKC) activator, 1-oleoyl-2-acetyl-sn-glycerol (OAG), and a specific cPKC inhibitor, G? 6976, suggested that PKC-delta and/or -epsilon is involved in uPA release. As opposed to the apoptotic pathway, however, no activation of c-Jun N-terminal kinase and nuclear factor kappa B was observed in C8-ceramide-stimulated microglia. The findings suggest that uPA release from microglia is regulated by a mechanism in which PKC-delta and/or -epsilon are activated and further signals are transduced subsequently.     

Expression of the urokinase plasminogen activator receptor (uPAR) and its ligand (uPA) in brain tissues of human immunodeficiency virus patients with opportunistic cerebral diseases

The urokinase plasminogen activator receptor (uPAR) and its ligand (uPA) play an important role in cell migration and extracellular proteolysis. We previously described uPAR/uPA overexpression in the cerebrospinal fluid (CSF) and brain tissues of patients with human immunodeficiency virus (HIV)-related cerebral diseases. In this study, we examined uPAR/uPA expression by immunohistochemistry (IHC) in brains of HIV patients with opportunistic cerebral lesions and in HIV-positive/negative controls. uPAR was found in macrophages/microglia with the highest levels in cytomegalo-virus (CMV) encephalitis, toxoplasmosis, and lymphomas; in cryptococcosis and progressive multifocal leukoencephalopathy (PML) cases, only a few positive cells were found and no positivity was observed in controls. uPA expression was demonstrated only in a few macrophages/microglia and lymphocytes in all the cases and HIV-positive controls without different pattern of distribution; no uPA immunostaining was found in cryptococcosis and HIV-negative controls. The higher expression of uPAR/uPA in most of the opportunistic cerebral lesions supports their role in these diseases, suggesting their contribution to tissue injury.     

Lipopolysaccharide differentially regulates microglial trk receptor and neurotrophin expression

Activated brain microglia play a pivotal role in inflammatory and degenerative disorders, mediating immune function and producing toxic and trophic agents. We previously reported that microglia express neurotrophins and that neurotrophin-3 (NT-3) increases microglial proliferation and phagocytosis, processes associated with cellular activation. However, mechanisms regulating responsiveness to NT-3 and expression of NT-3 in activated microglia remain undefined. To investigate mechanisms governing microglial responsiveness to neurotrophins, we determined whether microglia express trk C, the high-affinity receptor for NT-3, and whether the inflammatory agent lipopolysaccharide (LPS) regulates receptor expression. Trk C mRNA was expressed by unstimulated microglia, and both trk C mRNA and protein were dramatically increased by LPS. In contrast, expression of trk A, the high-affinity receptor for nerve growth factor (NGF), was down-regulated by LPS. Consequently, the same stimulus differentially influences responsiveness of microglia to distinct trophins. In addition, LPS induced microglial NT-3 expression, suggesting that increases in both the ligand and receptor modulate NT-3 effects on microglia. Regulation was specific, since brain-derived neurotrophic factor (BDNF) and NT-4/5 expression were unaltered by LPS. In sum, our findings raise the possibility that microglial NT-3 regulates their response to inflammation through autocrine mechanisms: LPS modulates both trk C and NT-3 which, in turn, regulate microglial function. J. Neurosci. Res. 54:117–122, 1998. © 1998 Wiley-Liss, Inc.     

Distinct populations of hypothalamic dopaminergic neurons exhibit differential responses to brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3)

We have previously demonstrated that differentiation of hypothalamic dopaminergic (DA) neurons can be induced in culture by their pituitary intermediate lobe target cells, through both membrane and diffusible factors. We also showed that subpopulations of DA neurons from the arcuate nucleus only, not the periventricular area, can respond to the target. Here we investigated the possibility that both neuronal subsets could also respond differentially to brain-derived neurotrophic factor (BDNF) or neurotrophin-3 (NT3). Addition of NT3, but not BDNF, enhanced growth and branching of neurites, tyrosine hydroxylase (TH) as well as increasing levels of cultured arcuate DA neurons. Conversely, BDNF, but not NT3, affected the same parameters in cultured periventricular DA neurons. The neurotrophins thus affect DA neurons in a structure and neuronal type-selective manner, since general neuronal markers were not affected by either neurotrophin. Neurotrophin effects were reversed by addition of specific antibodies directed against them or their respective receptors, TrkB or TrkC. By themselves, the antibodies inhibited development of DA neurons below that of control cultures, suggesting involvement of endogenous neurotrophins. BDNF and NT3 were indeed found in both arcuate and periventricular neurons and in the intermediate lobe. BDNF was always present as the mature peptide. The mature form of NT3 was only detected in the periventricular area; a precursor-like heavier form was present in all tissues studied. The present data suggest that NT3, but not BDNF, could participate in the differentiating action of intermediate lobe cells on arcuate DA neurons.     

Direct interaction of the kringle domain of urokinase-type plasminogen activator (uPA) and integrin alpha v beta 3 induces signal transduction and enhances plasminogen activation

It has been questioned whether there are receptors for urokinase-type plasminogen activator (uPA) that facilitate plasminogen activation other than the high affinity uPA receptor (uPAR/CD87) since studies of uPAR knockout mice did not support a major role of uPAR in plasminogen activation. uPA also promotes cell adhesion, chemotaxis, and proliferation besides plasminogen activation. These uPA-induced signaling events are not mediated by uPAR, but mediated by unidentified, lower-affinity receptors for the uPA kringle. We found that uPA binds specifically to integrin alpha v beta 3 on CHO cells depleted of uPAR. The binding of uPA to alpha v beta 3 required the uPA kringle domain. The isolated uPA kringle domain binds specifically to purified, recombinant soluble, and cell surface alpha v beta 3, and other integrins (alpha 4 beta 1 and alpha 9 beta 1), and induced migration of CHO cells in an alpha v beta 3-dependent manner. The binding of the uPA kringle to alpha v beta 3 and uPA kringle-induced alpha v beta 3-dependent cell migration were blocked by homologous plasminogen kringles 1-3 or 1-4 (angiostatin), a known integrin antagonist. We studied whether the binding of uPA to integrin alpha v beta 3 through the kringle domain plays a role in plasminogen activation. On CHO cell depleted of uPAR, uPA enhanced plasminogen activation in a kringle and alpha v beta 3-dependent manner. Endothelial cells bound to and migrated on uPA and uPA kringle in an alpha v beta 3-dependent manner. These results suggest that uPA binding to integrins through the kringle domain plays an important role in both plasminogen activation and uPA-induced intracellular signaling. The uPA kringle-integrin interaction may represent a novel therapeutic target for cancer, inflammation, and vascular remodeling.     

Microglia isolated from rat brain secrete a urokinase-type plasminogen activator.

In a previous study, we found particular proteases which degrade myelin basic protein (MBP) in a conditioned medium of cultured rat brain microglia. The MBP degrading activity in microglial-conditioned medium (Mic-CM) increased markedly in the presence of plasminogen. By Sephadex G-150 column chromatography, plasminogen-dependent MBP degrading activity was eluted at the position of about 47 kDa and 28 kDa. Furthermore slight plasminogen-dependent protease activity in the presence of fibrin (tissue plasminogen activator activity) was detected at a molecular weight of about 68 kDa. The two molecular forms (47 kDa and 28 kDa) of plasminogen-dependent protease were demonstrated by casein-zymography, and it was suggested that they were urokinase type-plasminogen activators (uPA). This suggestion was confirmed by immunoblotting using anti-uPA antiserum. The unique 28 kDa type was considered to be produced from the 47 kDa form by limited proteolysis. Secretion of PA from microglia was demonstrated by cell zymography. In contrast, significant secretion of plasminogen activator inhibitor could not be detected in the Mic-CM. In addition, lipopolysaccharide significantly decreased the secretion of PA from microglia, while interleukin-1 and basic fibroblast growth factor enhanced the secretion.     

Effects of endogenous neurotrophins on sympathetic sprouting in the dorsal root ganglia and allodynia following spinal nerve injury

Peripheral nerve injury is often complicated by a chronic pain syndrome that is difficult to treat. In animal models of peripheral nerve injury, sympathetic nerve terminals in the dorsal root ganglia (DRG) sprout to form baskets around large diameter neurons, an anatomical change that has been implicated in the induction of neuropathic pain. In the present study, we have investigated whether neurotrophins derived from peripheral sources play any roles in sympathetic sprouting and neuropathic pain in a rat model of peripheral nerve injury. After transection of the left lumbar (L) 5 spinal nerve, antisera specific to neurotrophins were injected intraperitoneally twice a week for 2 weeks. The foot withdrawal response to von Frey hairs was examined on days 1, 3, 7, 10, and 14 postlesion. After completion of behavioral tests, sympathetic sprouting in DRG was examined by tyrosine hydroxylase (TH) immunohistochemistry. The number of TH-immunoreactive (ir) fibers and baskets around large neurons within the lesioned DRG was dramatically increased in the rats treated with control normal sheep serum. Antisera specific to nerve growth factor (NGF), neurotrophin-3 (NT3), and brain-derived neurotrophic factor (BDNF) significantly reduced the sympathetic sprouting and the formation of baskets. L5 spinal nerve lesion induced a significant increase in foot withdrawal responses to von Frey hair stimuli, which was attenuated by treatment of antisera to neurotrophins with a different time sequential. The effect of BDNF antiserum occurred earlier and lasted longer than those of NGF and NT3 antisera. These results implicate that peripherally derived neurotrophins are involved in the induction of sympathetic sprouting and neuropathic pain following peripheral nerve injury.