Trophic factors for Parkinson's disease: To live or let die

Trophic factors show great promise in laboratory studies as potential therapies for PD. However, multiple double‐blind, clinical trials have failed to show benefits in comparison to a placebo control. This article will review the scientific rationale for testing trophic factors in PD, the results of the different clinical trials that have been performed to date, and the possible explanations for these failed outcomes. We will also consider future directions and the likelihood that trophic factors will become a viable therapy for patients with PD. © 2015 International Parkinson and Movement Disorder Society     

针刺对背根节神经元GDNF表达的影响

目的 研究部分去背根及针刺对背根神经节神经元胶质细胞源性神经营养因子（GDNF）表达的影响。方法 制作猫备用背根模型并针刺备用根支配区的两组穴位，足三里和悬钟，伏兔和三阴交。针刺7d后取备用背根节用GDNF抗血清（1：1000）行免疫组织化学染色。分别计数各组大，中，小阳性神经元的数值。结果 非手术组GDNF阳性神经元数量为55％。其中大神经元为25％，中神经元为14％，小神经元为16％，术后非针刺组，阳性神经元总数为35％，较非手术组明显下降（P＜0．05），主要为大神经元（5％）减少，而阳性少（13％），小神经元（17％）数量变化不明显，但染色明显加深。针刺组GDNF阳性神经元数量又明显增加至90％，其中阳性大神经元28％，中神经元17％，小神经元45％。结论 背根节GDNF阳性大神经元数量在去部分背根术后7d显著下降，而针刺可逆转这种变化。GDNF阳性中，小神经元数量在术后7d并无明显变化，但针刺后表达显著增加。     

大鼠骨髓基质细胞分泌胶质细胞源性神经营养因子的研究

目的研究骨髓基质细胞(BMSCs)能否分泌胶质细胞源性神经营养因子(GDNF)及其分泌规律，为进一步探讨BMSCs治疗帕金森病(PD)大鼠模型的作用机制提供实验依据。方法取较高纯度的BMSCs进行培养，通过RT—PCR和ELISA法，分别从mRNA和细胞蛋白水平测定体外培养BMSCs的上清液和细胞蛋白中GDNF的含量。结果通过RT-PCR法检测结果显示在mRNA水平，BMSCs中有GDNF的表达。在蛋白水平，采用ELISA法在培养第3天以后的培养液和细胞蛋白中均可检测到GDNF，并随着时间的延长，培养液和细胞蛋白中GDNF浓度明显升高。结论BMSCs具有分泌GDNF的能力，细胞分泌可能受周围环境和自身生长状况的影响，其分泌是非持续性的。GDNF浓度的升高不仅与BMSCs细胞数量增加有关，还与细胞本身分泌能力的增强有关。     

Down-regulation of GFRalpha-1 expression by antisense oligodeoxynucleotide aggravates thermal hyperalgesia in a rat model of neuropathic pain

Glial cell line-derived neurotrophic factor (GDNF) has been hypothesized to play an important role in the modulation of nociceptive signals especially during neuropathic pain. The present study examined the expression of GDNF and GFRalpha-1 (the high-affinity receptor of GDNF) in dorsal root ganglions (DRG) in a rat model of neuropathic pain induced by chronic constriction injury (CCI) to the sciatic nerve. In order to address the role of GDNF and GFRalpha-1 in neuropathic pain, antisense oligodeoxynucleotide (ODN) specifically against GFRalpha-1 was intrathecally administered to result in down-regulation of GFRalpha-1 expression. The results showed that both the protein and mRNA levels of GDNF and GFRalpha-1 were significantly increased after CCI, while the thermal hyperalgesia of neuropathic pain rats could be significantly aggravated by antisense ODN treatment, but not by normal saline (NS) or mismatch ODN treatment. The present study demonstrated that endogenous GDNF and GFRalpha-1 might play an anti-hyperalgesic role in neuropathic pain of rats. In addition, we found a down-regulation of somatostatin (SOM) in DRG and spinal dorsal horn after expression of GFRalpha-1 was knocked down, which suggested the possible relationship between the anti-hyperalgesic effect of GDNF and GFRalpha-1 on neuropathic pain and endogenous SOM.     

The role of glial cell line-derived neurotrophic factor (GDNF) and integrins for invasion and metastasis in human pancreatic cancer cells

BACKGROUND AND OBJECTIVES: It is generally accepted that the malignancy of pancreatic cancer is dependent upon the extent of invasion as well as metastasis. However, the factors and mechanisms are incompletely understood. We investigated whether glial cell lined-derived neurotrophic factor (GDNF) enhances the invasive and adhesive behaviors of pancreatic cancer cells by altering of the expression of integrins. METHODS: The expression of the GDNF receptor in pancreatic cancer cell lines (SW1990 and Capan-2) was confirmed by RT-PCR. Then we determined the expression of integrin subunits and the alteration of their expression by GDNF using flow-cytometric analysis and a cellular enzyme-linked immunosorbent assay (CELISA). Adhesion and invasion assay were performed to investigate whether increased integrin expression affected the interaction between cancer cells and ECM proteins. RESULTS: The GDNF receptor subunits were expressed in pancreatic cancer cells. GDNF enhanced the expression of some of the integrin subunits and increased their adhesive and invasive abilities. The enhanced expression and associated increase in adhesive and invasive abilities were inhibited by blocking the GDNF receptor or the integrin beta1 subunit. CONCLUSION: The enhancement of integrin expression by GDNF signaling through the GDNF receptor strongly influences invasion and adhesion to ECM proteins by pancreatic cancer cells.     

Early changes of LIFR and gp130 in sciatic nerve and muscle of diabetic mice

Peripheral neuropathy is a common complication of diabetes mediated by alterations of growth factors. Members of the neuropoietic cytokine family, which include IL-6, LIF, and CNTF among others, have been shown to be important regulators of peripheral nerves and the muscles that they innervate. To investigate their potential role in diabetic nerve and muscle, we studied the expression of the shared receptor subunits, LIFR and gp130 in a mouse model of streptozotocin (STZ)-induced diabetes. The results of Western blotting and densitometric analysis showed that both LIFR and gp130 protein expression were increased in diabetic sciatic nerve compared to control mice at early time points following STZ injection. In diabetic gastrocnemius muscle, LIFR and gp130 were increased from 3 days to 24 weeks following STZ injection. In contrast, both LIFR and gp130 protein expression were decreased in diabetic soleus muscle at 3-days post-injection. Our results suggest that hyperglycemia results in changes to nerve and muscle soon after the onset of diabetes and that cytokines may play a role in this process.     

GDNF基因修饰的神经干细胞抑制脑卒中后大鼠的Caspase-3表达

目的研究胶质源性神经营养因子(glial cell line-derived neural factor,GDNF)基因修饰的神经干细胞(neuralstem cells,NSCs)移植对脑卒中后大鼠缺血侧脑组织内半胱氨酰天冬氨酸特异性蛋白酶-3(cysteinyl aspartate specific protein-ase-3,caspase-3)表达的影响,探讨GDNF基因修饰的神经干细胞(GDNF/NSCs)移植对大鼠脑卒中的神经保护作用机制。方法取新生大鼠脑组织分离培养NSCs,收集第6代前的NSCs备用。用重组腺病毒GDNF转染神经干细胞,制备GDNF/NSCs。暂时性阻塞大鼠大脑中动脉制备脑卒中模型,3d后,用脑立体定位仪向卒中侧侧脑室分别给予NSCs、GDNF/NSCs和生理盐水。再灌注时间1周、2周、3周、5周、7周后处死大鼠(n=3)。裂解卒中侧脑组织,离心后得到脑组织蛋白样品,通过蛋白免疫印迹(Western Blotting)检测Caspase-3表达。结果 GDNF/NSCs、NSCs、NS各组caspase-3的表达在1周、2周、3周、5周、7周各时间点均逐渐降低。NSCs组、GDNF/NSCs组显著低于NS组(P<0.01;P<0.001);GDNF/NSCs组明显低于NSCs组(P<0.01)。结论 GDNF/NSCs移植治疗脑卒中的机制可能与抑制caspase-3表达有关。     

大鼠局灶性脑缺血再灌注后GDNF mRNA及其蛋白表达的变化

目的 观察大鼠脑缺血再灌注后缺血半暗带皮质脑源性神经营养因子(GDNF) mRNA和蛋白的表达变化.方法 采用线栓法制作局灶性脑缺血大鼠(MCAO)模型,用原位杂交法和免疫组化法观察脑缺血后3、6、12 h及l、3、7d共6个时间点GDNFmRNA及其蛋白的表达变化.结果 缺血半暗带GDNFmRNA及其蛋白的表达均于缺血灌注后3h开始明显上升,6h达高峰,12 h表达开始减弱(P＜0.05或P＜0.01),3-d后降至正常水平.结论 脑缺血再灌注后缺血半暗带GDNFmRNA及蛋白表达均明显增加可能参与了脑缺血后神经保护.     

Distribution of acid sphingomyelinase in rodent and non-human primate brain after intracerebroventricular infusion

One treatment approach for lysosomal storage diseases (LSDs) is the systemic infusion of recombinant enzyme. Although this enzyme replacement is therapeutic for the viscera, many LSDs have central nervous system (CNS) components that are not adequately treated by systemic enzyme infusion. Direct intracerebroventricular (ICV) infusion of a high concentration of recombinant human acid sphingomyelinase (rhASM) into the CNS over a prolonged time frame (hours) has shown therapeutic efficacy in a mouse model of Niemann–Pick A (NP/A) disease. To evaluate whether such an approach would translate to a larger brain, rhASM was infused into the lateral ventricles of both rats and Rhesus macaques, and the resulting distribution of enzyme characterized qualitatively and quantitatively. In both species, ICV infusion of rhASM resulted in parenchymal distribution of enzyme at levels that were therapeutic in the NP/A mouse model. Enzyme distribution was global in nature and exhibited a relatively steep gradient from the cerebrospinal fluid compartment to the inner parenchyma. Additional optimization of an ICV delivery approach may provide a therapeutic option for LSDs with neurologic involvement.     

大鼠骨髓间充质干细胞体外向肠神经细胞分化及胶质细胞源神经营养因子表达的变化

目的 探讨大鼠骨髓间充质干细胞向肠神经分化的条件及胶质细胞源神经营养因子(glial cellline-derived neurotrophic factor,GDNF)及其受体RET基因表达的变化.方法 体外培养大鼠骨髓间充质干细胞(bone marrow stromal cells,BMSCs),传至第四代,进行诱导分化.以10ng/ml GDNF和10%FBS的稀释胎肠培养基(fetal gut culture medium,FCCM)以及仅含有10 ng/ml GDNF的L-DMEM诱导7 d,对照组为含10%FBS的L-DMEM完全培养液,免疫组化的方法鉴定细胞的神经特异性烯醇化酶(neural specific enolase,NSE)、血管活性肠肽(vasoactive intestinal peptide,VIP)及一氧化氮合酶(nit ric oxide synthase,nNOS)的表达.RT-PCR检测GDNF及RET mRNA的变化,Westem Blot方法检测GDNF蛋白的表达情况.结果 BMSCs能在体外成功培养及纯化,诱导7 d后,实验组均可见NSE、VIP及nNOS的表达,两实验组的阳性率有统计学差异,而对照组为阴性.RT-PCR检测示,BMSCs向肠神经细胞诱导后,GDNF表达显著增强,并促使RET基因表达Western Blot结果提示,诱导后的细胞GDNF在蛋白水平上表达增强.结论 GDNF联合FCCM可诱导BMSCs分化为肠神经细胞,在向神经细胞分化的过程中,能促进GDNF表达的增强,并促使RET基因的表达,GDNF-RET信号通路在肠神经分化过程中可能发挥着重要作用.