Effect of α-synuclein on the promoter activity of tyrosine hydroxylase gene

Objective To approach the associated mechanism by which α-synuclein （α-Syn） might regulate the metabolism of dopamine. Methods A DNA fragment, located at --495 to ＋25 of the human tyrosine hydroxylase （TH） gene, was amplified by PCR and inserted into the pGL3-Basic luciferase reporter vector. The recombinant plasmid pGL3-THprom was transfected into a dopammergic cell line MES23.5 or a α-Syn over-expressed MES23.5 （named MES23.5/hα-Syn^＋）. The promoter activity was detected by the Dual Luciferase Assay System. Results The luciferase activities in the MES23.5 cells transfected with pGl.,3-Basic, pGL3-THprom, and pGL3-Control vectors were 5.60±0.67, 26.80±4.11, and 32.90±4.75, respectively. On the other hand, the luciferase activity of pGL3-THprom in the MES23.5 （26.80±4.11） was significantly higher than that in the MES23.5/hα-Syn^＋（14.40±0.61） （P〈0.01）. Conclusion These results indicate that the -495 to ＋25 region in the TH gene possesses promoter activity for controlling the gene expression, and that α-Syn may negatively regulate the metabolism of dopamine by affecting the function of TH promoter as a trans-acting factor.

Verbascoside promotes the regeneration of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra

Tyrosine hydroxylase is a key enzyme in dopamine biosynthesis. Change in tyrosine hydroxylase expression in the nigrostriatal system is closely related to the occurrence and development of Parkinson＇s disease. Verbascoside, an extract from Radix Rehmanniae Praeparata has been shown to be clinically effective in treating Parkinson＇s disease. However, the underlying mechanisms remain unclear. It is hypothesized that the effects of verbascoside on Parkinson＇s disease are related to tyrosine hydroxylase expression change in the nigrostriatal system. Rat models of Parkinson＇s disease were established and verbascoside（60 mg/kg） was administered intraperitoneally once a day. After 6 weeks of verbascoside treatment, rat rotational behavior was alleviated; tyrosine hydroxylase m RNA and protein expression and the number of tyrosine hydroxylase-immunoreactive neurons in the rat right substantia nigra were significantly higher than the Parkinson＇s model group. These findings suggest that the mechanism by which verbascoside treats Parkinson＇s disease is related to the regeneration of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra.

舒肌汤对L-DOPA诱发的帕金森病肌僵直大鼠的作用及其脑组织TH、DA含量和FosB、p-ERK蛋白的影响

目的:观察舒肌汤对左旋多巴(Levodopa,L-DOPA)诱发的帕金森病(Parkinson’s disease,PD)肌僵直模型大鼠的影响,并探讨其作用机制。方法:L-DOPA诱导建立PD肌僵直大鼠模型,随机分为模型组(等体积生理盐水),舒肌汤低、中、高剂量组(10、20、40 g/kg),同时设假手术组(等体积生理盐水)作为对照,每组6只大鼠,每天灌胃给药1次,连续给药28 d。给药完成后通过旋转次数实验、翻正反射实验、肌电图检测行为学表现。免疫组化检测脑组织酪氨酸羟化酶(tyrosine hydroxylase,TH)表达水平。ELISA检测脑纹状体组织多巴胺(dopamine,DA)和TH的含量。Western blot检测脑纹状体组织FBJ鼠科骨肉瘤病毒癌基因同源物B(FBJ Murine Osteosarcoma Viral Oncogene Homolog B,FosB)、磷酸化细胞外信号调节激酶(phosphorylation-extracellular signal-regulated kinase,p-ERK)蛋白表达水平。结果:与假手术组相比,模型组大鼠旋转次数、翻正反射时间与评分、肌肉动作电位波幅和潜伏期显著升高或延长(P<0.01),MCV显著降低(P<0.01);与模型组相比,舒肌汤组大鼠旋转次数、翻正反射时间与评分、肌肉动作电位波幅和潜伏期显著降低或缩短(P<0.05),MCV显著升高(P<0.01)。免疫组化结果显示舒肌汤可上调脑组织TH表达水平;ELISA结果显示舒肌汤可上调DA和TH含量。Western blot结果显示舒肌汤可下调FosB、p-ERK蛋白表达水平。结论:舒肌汤对帕金森病模型大鼠肌僵直有显著疗效,其作用机制可能与上调DA和TH含量、下调FosB、p-ERK蛋白表达有关。

TH基因变异致多巴反应性肌张力障碍二例

例1女性,8岁,主因独立行走不能6年余,于2011年8月10日至我院神经内科门诊就诊。患儿于出生后约15月龄时(2004年10月)受凉后发热(约39℃)而出现肢体活动差,表现为四肢活动减少,独自站立不能,症状呈进行性加重,尤以受凉、上呼吸道感染后症状明显加重。2岁时仍无法独立行走,需他人扶行,并出现四肢关节挛缩,症状有日间波动性,晨轻暮重。曾于外院就诊,具体检查和诊断不详,未予治疗。家属诉患儿出生史及1岁以内语言、运动等生长发育史均正常;父母非近亲婚配,否认家族中有类似疾病病史。

Tyrosine Hydroxylase as a Target for Deltamethrin in the Nigrostriatal Dopaminergic Pathway

Objective To study the effects of deltamethrin on tyrosine hydroxylase in nigrostriatum of male rats. Methods Sprague-Dawley rats were daily treated with deltamethrin at 6.25 or 12.5 mg/kg body weight by gavage for 10 days. Then HPLC-fluorescence detection was used to analyze the contents of dopamine （DA）, 3,4-dihydmxyphenylacetic acid （DOPAC） and homoranillic acid （HVA） in substantial nigra and striatum. The activities of tyrosine hydroxylase （TH） were also detected by HPLC-fluorescence detection. TH mRNA or TH protein levels were measured by RT-PCR and immunohistochemistry method. Results The content of DA in stfiatum was significantly decreased by the treatments, suggesting an inhibition of DA synthesis by deltamethrin. The contents of DA metabolites DOPAC and HVA increased, indicating increased dopamine turnover. Furthermore, deltamethrin significantly decreased the activity, as well as the mRNA and protein levels of TH. Conclusions These findings reveal a novel aspect of deltamethfin neurotoxicity and suggest tyrosine hydroxylase as a molecular target of deltamethin on dopamine metabolism in the nigrostriatal pathway.

Tyrosine hydroxylase expression in the midbrain of Parkinson's disease model rats treated with Xifeng Dingchan decoction

This study showed that abnormal behavioral changes were greatly improved in rats displaying Parkinson＇s disease-like symptoms after intragastric administration of Xifeng Dingchan decoction at 15, 7.5, 3.75 g/kg per day. In addition, tyrosine hydroxylase mRNA expression in the substantia nigra of the midbrain was up-regulated, and tyrosine hydroxylase content in the midbrain ventral tegmentum and substantia nigra pars compacta was also increased. The effect of administration of Xifeng Dingchan decoction at 7.5 g/kg per day was similar to that of Madopar at 67.5 mg/kg per day. These results indicate that the therapeutic effect of Xifeng Dingchan decoction on Parkinson＇s disease is associated with the up-regulated protein and mRNA expression of tyrosine hydroxylase in the midbrain.

CHCHD2 Thr61Ile mutation impairs F1F0-ATPase assembly in in vitro and in vivo models of Parkinson's disease

Mitochondrial dysfunction is a significant pathological alte ration that occurs in Parkinson's disease(PD),and the Thr61lle(T61I)mutation in coiled-coil helix coiled-coil helix domain containing 2(CHCHD2),a crucial mitochondrial protein,has been reported to cause Parkinson's disease.FIFO-ATPase participates in the synthesis of cellular adenosine triphosphate(ATP)and plays a central role in mitochondrial energy metabolism.However,the specific roles of wild-type(WT)CHCHD2 and T611-mutant CHCHD2 in regulating F1FO-ATPase activity in Parkinson's disease,as well as whether CHCHD2 or CHCHD2 T61I affects mitochondrial function through regulating F1FO-ATPase activity,remain unclea r.Therefore,in this study,we expressed WT CHCHD2 and T61l-mutant CHCHD2 in an MPP^(+)-induced SH-SY5Y cell model of PD.We found that CHCHD2 protected mitochondria from developing MPP^(+)-induced dysfunction.Under normal conditions,ove rexpression of WT CHCHD2 promoted F1FO-ATPase assembly,while T61I-mutant CHCHD2 appeared to have lost the ability to regulate F1FO-ATPase assembly.In addition,mass spectrometry and immunoprecipitation showed that there was an interaction between CHCHD2 and F1FO-ATPase.Three weeks after transfection with AAV-CHCHD2 T61I,we intraperitoneally injected 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine into mice to establish an animal model of chronic Parkinson's disease and found that exogenous expression of the mutant protein worsened the behavioral deficits and dopaminergic neurodegeneration seen in this model.These findings suggest that WT CHCHD2 can alleviate mitochondrial dysfunction in PD by maintaining F1F0-ATPase structure and function.

Treatment time influences the effects of a low-frequency pulsed electric field on synthesis of tyrosine hydroxylase and dopamine in PC12 cells

BACKGROUND： Electromagnetic radiation can influence dopamine （DA） synthesis in brain tissues or ceils, but electromagnetic frequencies, intensities, and radiation time can produce different effects. In addition, the signal pathway by which electromagnetic radiation influences DA synthesis remains controversial. OBJECTIVE： To determine tyrosine hydroxylase （TH） expression in PC12 cells and DA levels in cell culture media after different periods of low-frequency pulsed electric field （LF-PEF） stimulation, and to determine how LF-PEF signaling stimulates TH synthesis using inhibitors. DESIGN, TIME AND SETTING： A parallel, controlled, cell experiment was performed at the Laboratory of Cell Biology, School of Life Science, East China Normal University, between January and October 2006. MATERIALS： PC12 cells were purchased from the Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, China. Nerve growth factor was purchased from PeproTech, USA. The protein kinase A inhibitor, H-89, and mitogen-activated protein kinase kinase inhibitor, U0126, were purchased from Sigma, USA. METHODS： （1） Following routine culture in Dulbecco＇s modified eagle medium, primary PC12 cells were stimulated under LF-PEF （pulse frequency 50.Hz, pulse width 20 μs, peak field strength 1 V/m） for 5, 10, 15, 20, and 30 minutes. （2） Inhibitors （H-89 or U0126, 1 μmol/L） were added 30 minutes before LF-PEF stimulation for 10 minutes. MAIN OUTCOME MEASURES： （1） TH expression was determined by Western blot in PC12 cells at 0.5, 1,2, 3, and 4 days after LF-PEF stimulation. Similarly, DA was measured by high-performance liquid chromatography in media at 2, 3, 4, or 5 days after LF-PEE （2） TH expression was detected 1 day after H-89 or U0126 treatment and LF-PEE RESULTS： （1） Short-term LF-PEF stimulation （5 and 10 minutes） increased TH expression and media DA levels after short-term culture （2 days） （P 〈 0.01）, but both parameters decreased with longer culture （3 4 days） （P 〈 0.01）. Long-term LF-PEF stimulation （15, 20, or 30 minutes） decreased TH and DA synthesis, followed by a rapid increase （P 〈 0.01）. （2） H89 could completely inhibit TH expression in PC12 cells stimulated by LF-PEF for 10 minutes, while the inhibition rate of U0126 was 53.2%. CONCLUSION： Short-term LF-PEF first promotes then inhibits, while long-term LF-PEF first inhibits then promotes, TH and DA synthesis. LF-PEF stimulation regulates TH expression primarily by activating protein kinase A to regulate DA synthesis.

Tyrosine hydroxylase and Lewy body molecules immunoreactivity in the SNC neurons of an AS/AGU mutantrat

The AS/AGU rat has a recessive single point mutation in the gene coding for the gamma isoform of protein kinase C (PKC-γ) resulting in a failure to release dopamine in the striatum and impaired movement including a staggering gait, difficulty in initiating movement and a slight whole body tremor. This study examined the levels tyrosine hydroxylase, ubiquitin and parkin in individual SNC cell bodies, there was no evidence of a reduction in tyrosine hydroxylase levels although levels of ubiquitin and parkin were elevated in the cytoplasm. The findings support the hypothesis that the initial bar to dopamine availability in the striatum is reduced release, with substantia nigra cell death being a later phenomenon.

COEXISTENCE OF FOS-LIKE PROTEIN IN TYROSINE HYDROXYLASE-LIKE IMMUNOREACTIVE NEURONS IN THE HINDBRAIN OF ARTS FOLLOWING PERIPHERAL ELECTRICAL STIMULATION

In the present study we have found that proto-oncogene c-fos protein can expressin the noradrenergic neurons of rat hindbrain following peripheral electrical stimulation. Ratswere given peripheral electrical stimulation via thin stainless steel pins inserted into the pointsnear knee joint (S36) and ankle joint (Sp6) which mimic the manipulation of electroacupuncture(EA) performed in humans. Animals were perfused for double staining immunohistochemistry 2hafter the termination of EA. In rats subjected to EA stimulation Fos-like protein was found in thetyrosine hydroxylase (TH)-like immunoreactive neurons in rat hindbrain. The Fos and TH coex-isting neurons were distributed in the locus coeruleus, solitary tract nucleus, ventrolateral medul-la, periaqeductal gray, as well as superior colliculus. The percentage of the coexisting neuronscompared with the total number of neurons containing Fos-like protein in these nuclei rangedfrom 6% to 32%. The results suggest that the noradrenergic neurons in these regions may be ac-tivted by acupuncture stimulation.

Tyrosine hydroxylase gene transfections to different sites of striatum in the rat model of Parkinson’s disease

The use of gene therapy has been intensively studied as a potential method to treat Parkinson’s disease (PD) and other degenerative brain diseases. However, the effects of experimental measures and approaches on the outcome of gene delivery or on the physiological state of target tissues have not been analyzed as much and systematically. Therefore, we have infused adenovirus vectors expressing either a therapeutic tyrosine hydroxylase (TH) gene or a lacZ reporter gene into striatum in a rat model of PD. The experimental procedures were tested using the Ad lacZ vector in order to optimize concentrations, volumes, infusion speeds and transfection times. The expression of Ad lacZ vector was lower and declined earlier in the lesioned than unlesioned striatum suggesting that the lesion affects on the transfection efficiency and outcome of gene transfection. The effect of three different approaches of Ad TH vector transfection was compared: 1) the delivery of Ad TH gene vector alone into one single site of striatum, 2) the delivery of Ad TH gene vector alone into multiple sites of striatum, and 3) the delivery of Ad TH gene vector into one site of striatum followed by a continuous infusion of tetrahydrobiopterin (BH4) cofactor with a mini pump. There was a small and transient unsignificant decrease in the turning behavior when the Ad TH vector was delivered into one site of the striatum. Simultaneous infusion into several sites or together with BH4 cofactor did not improve more the effect of gene delivery. Thus, although the effects were unsignificant, the Ad TH transfection seemed to decrease the turning behavior in the rat model of PD and the optimal effect was seen at some specific doses and time points. Furthermore, the outcome of gene therapy could depend in addition to the amount and efficacy of gene vectors also on the physiological state and experimental strategies.

刮痧对鱼藤酮诱导的帕金森病大鼠行为学及黑质区TH水平和炎症因子的影响

目的观察刮痧对鱼藤酮诱导的帕金森病(PD)模型大鼠行为学及黑质酪氨酸羟化酶(TH)、核因子κB(NF-κB)、γ干扰素(IFN-γ)、白细胞介素-1β(IL-1β)的影响,探究刮痧干预PD可能的作用机制。方法32只SD雄性大鼠随机分为假手术组、模型组、药物组和刮痧组,每组8只。模型组、药物组和刮痧组大鼠采用颈背部皮下注射鱼藤酮(1 mg·kg^(-1))建立PD大鼠模型。药物组每天给予美多芭灌胃(50 mg·kg^(-1)),刮痧组隔日刮痧1次,刮12次,共计23 d。造模前、造模后、干预结束观察大鼠行为学改变;干预结束,采用Western blot和免疫荧光检测黑质区TH表达,免疫组化法检测黑质TH、NF-κB表达,ELISA法检测中脑黑质NF-κB、IFN-γ、IL-1β含量,HE染色观察纹状体区细胞形态。结果与假手术组相比,模型组大鼠行为学评分(3.42±1.248),5 min内运动总距离缩短(P<0.0001),起点停留时间延长(P<0.05),悬尾5 min内静止时间明显延长(P<0.001),中脑黑质TH表达减少(P<0.001),黑质NF-κB、IFN-γ、IL-1β含量均增加(P<0.0001),纹状体区细胞肿胀明显(P<0.05)。与模型组相比,刮痧组大鼠5 min内运动总距离增加(P<0.05)、起点停留时间缩短(P<0.05)、悬尾5 min内静止时间缩短(P<0.05),黑质区TH表达增加(P<0.05),黑质NF-κB、IFN-γ、IL-1β含量均下降(P<0.05),纹状体区细胞肿胀情况改善(P<0.0001)。刮痧组与药物组相比,各项指标差异均无统计学意义。结论刮痧可改善鱼藤酮诱导的PD大鼠的运动功能障碍,其机制可能与下调炎性因子表达,抑制神经炎性反应,减少多巴胺能神经元丢失,发挥神经保护作用有关。

Dark rearing maintains tyrosine hydroxylase expression in retinal amacrine cells following optic nerve transection

The present study examined changes in retinal tyrosine hydroxylase （TH） expression in rats having undergone optic nerve transection and housed under a normal day/night cycle or in the dark. The aim was to investigate the effects of amacrine cells on axonal regeneration in retinal ganglion cells and on the synapses that transmit visual signals. The results revealed that retinal TH expression gradually decreased following optic nerve transection in rats housed under a normal day/night cycle reaching a minimum at 5 days. In contrast, retinal TH expression decreased to a minimum at 1 day following optic nerve transection in dark reared rats, gradually increasing afterward and reaching a normal level at 5 7 days. The number of TH-positive synaptic particles correlated with the TH levels indicating that dark rearing can help maintain TH expression during the synaptic degeneration stage （5 7 days after optic nerve injury） in retinal amacrine cells.

Single-nuclei RNA sequencing uncovers heterogenous transcriptional signatures in Parkinson's disease associated with nuclear receptor-related factor 1 defect

Previous studies have found that deficiency in nuclear receptor-related factor 1(Nurr1),which participates in the development,differentiation,survival,and degeneration of dopaminergic neurons,is associated with Parkinson s disease,but the mechanism of action is perplexing.Here,we first asce rtained the repercussion of knocking down Nurr1 by pe rforming liquid chromatography coupled with tandem mass spectrometry.We found that 231 genes were highly expressed in dopaminergic neurons with Nurr1 deficiency,14 of which were linked to the Parkinson’s disease pathway based on Kyoto Encyclopedia of Genes and Genomes analysis.To better understand how Nurr1 deficiency autonomously invokes the decline of dopaminergic neurons and elicits Parkinson’s disease symptoms,we performed single-nuclei RNA sequencing in a Nurr1 LV-shRNA mouse model.The results revealed cellular heterogeneity in the substantia nigra and a number of activated genes,the preponderance of which encode components of the major histocompatibility Ⅱ complex.Cd74,H2-Ab1,H2-Aα,H2-Eb1,Lyz2,Mrc1,Slc6α3,Slc47α1,Ms4α4b,and Ptprc2 were the top 10 diffe rentially expressed genes.Immunofluorescence staining showed that,after Nurr1knockdown,the number of CD74-immunoreactive cells in mouse brain tissue was markedly increased.In addition,Cd74 expression was increased in a mouse model of Parkinson’s disease induced by treatment with 6-hydroxydopamine.Ta ken togethe r,our res ults suggest that Nurr1 deficiency results in an increase in Cd74 expression,thereby leading to the destruction of dopaminergic neuro ns.These findings provide a potential therapeutic target for the treatment of Parkinson’s disease.

A RAPID FLUORIMETRIC DETERMINATION OF TYROSINE IN SERUM BY THE REACTION WITH CERIUM (Ⅳ)

A fluorimetric method for the determination of tyrosine in serum was proposed. The fluoriscence intensity is a linear function of tyrosine content in the range 0-1. 44ug/ml. The percentage of recovery was satisfactory.

电针结合天麻素对PD模型大鼠黑质TH、TNF-α表达的影响

目的观察电针结合天麻素对帕金森病(PD)大鼠黑质酪氨酸羟化酶(TH)和肿瘤坏死因子-α(TNF-α)表达的影响,探讨电针结合天麻素对PD的保护机制。方法将50只SD大鼠随机分为正常组、模型组、电针组、天麻素组和电针结合天麻素组,每组10只。PD动物模型采用颈背部皮下注射鱼藤酮来造模,天麻素组给予天麻素腹腔注射;电针组给予高频电针治疗;电针结合天麻素组先天麻素腹腔注射,再电针治疗;三组均治疗21 d。采用免疫组织化学法和Western Blot检测黑质TH和TNF-α的表达。结果与正常组相比,模型组大鼠黑质TH表达减少(P<0.01),天麻素、电针和电针结合天麻素治疗后TH表达增加(P<0.01);与天麻素组和电针组相比,电针结合天麻素组TH表达增加(P<0.05)。与正常组相比,模型组大鼠黑质TNF-α表达增加(P<0.01),天麻素、电针和电针结合天麻素治疗后黑质TNF-α表达减少(P<0.01),与天麻素组和电针组相比,电针结合天麻素组TNF-α表达减少(P<0.05)。结论电针结合天麻素可上调PD大鼠黑质TH表达,下调TNF-α表达,且作用强于天麻素或电针。

外周血酪氨酸羟化酶含量与首发抑郁症的相关性研究

目的探讨外周血酪氨酸羟化酶(TH)含量与首发抑郁症的相关性,为阐明抑郁症的临床诊断及发病机制提供科学依据。方法选取2021年7月至2022年9月在我院就诊的40例首发抑郁症患者为病例组,另选取在我院体检中心进行健康体检的46名健康者为对照组。两组研究对象均进行汉密尔顿焦虑量表(HAMA)和汉密尔顿抑郁量表(HAMD)评分,并采集外周血测定TH含量。比较两组的TH含量及在不同性别和不同年龄段中的含量;通过偏相关分析TH含量与HAMA、HAMD评分的相关性;通过受试者工作特征曲线(ROC)的曲线下面积(AUC)来评价TH对抑郁症的诊断价值。结果病例组的TH含量显著低于对照组(P<0.05)。病例组的HAMA、HAMD评分与TH含量呈负相关(P<0.05)。ROC曲线分析显示,TH预测抑郁症的AUC为0.660。结论外周血TH含量降低可能与首发抑郁症的发生和发展有关,可作为抑郁症的生物学标志,对预测抑郁症具有一定的临床价值。

蛋白酶体抑制剂MG132对慢性缺氧致小鼠记忆损伤的作用及其机制

目的探讨蛋白酶体抑制剂MG132对慢性缺氧所致小鼠记忆功能损伤的作用及其机制。方法(1)利用低氧工作站构建小鼠中脑多巴胺能神经元MN9D细胞缺氧损伤模型。将MN9D细胞分为常氧组及缺氧12 h、24 h和48 h组,观察缺氧对MN9D细胞中酪氨酸羟化酶(TH)、泛素的K48链(Ub-K48)和Ub-K63表达的影响;将MN9D细胞分为常氧组、缺氧组、缺氧+MG132(25、50、100、200)μmol/L组,观察MG132对缺氧细胞中上述蛋白表达的影响。(2)利用低压舱建立低压缺氧小鼠记忆功能损伤模型。将C57小鼠随机分为常氧组、缺氧3 d组、缺氧21 d组,每组10只,观察低压低氧对小鼠中脑黑质致密部(SNc)TH、Ub-K48和Ub-K63表达的影响;将小鼠随机分为常氧组、缺氧21 d组、缺氧21 d+MG132组,每组8只,观察MG132对缺氧所致小鼠空间记忆损伤的影响。(3)采用Western blotting检测不同缺氧时长及MG132预处理再低氧处理的MN9D细胞中TH、Ub-K48和Ub-K63的蛋白表达水平;采用新物体识别测试检测各组小鼠记忆功能,免疫荧光染色检测SNc区TH阳性免疫反应面积百分比,Western blotting检测小鼠SNc区TH、Ub-K48和Ub-K63表达水平。结果(1)与常氧组比较,缺氧24 h组MN9D细胞中Ub-K48和Ub-K63表达水平增高(P<0.05),TH表达水平降低(P<0.05);各缺氧组Ub-K48/TH和Ub-K63/TH表达水平均增高(P<0.05)。与缺氧组比较,缺氧+MG132100μmol/L组和缺氧+MG132200μmol/L组MN9D细胞中Ub-K48/TH和Ub-K63/TH表达水平降低(P<0.05)。(2)与常氧组比较,缺氧3 d组和缺氧21 d组小鼠中脑SNc区TH表达水平降低(P<0.001),Ub-K48/TH和Ub-K63/TH表达水平升高(P<0.05);缺氧21 d组小鼠新物体识别指数降低(P<0.01),SNc区多巴胺能神经元TH阳性免疫反应面积百分比降低(P<0.05)。与缺氧21 d组比较,缺氧21 d+MG132组小鼠新物体识别指数升高(P<0.01)。结论蛋白酶体抑制剂MG132可改善慢性缺氧所致小鼠记忆损伤,其机制可能与抑制Ub-K48和Ub-K63,上调多巴胺能神经元TH表达有关。

美多巴和中药合用对帕金森病大鼠酪氨酸羟化酶(TH)及TH mRNA的影响

目的探讨中西药合用治疗帕金森病(PD)的作用机制。方法采用6-羟基多巴胺(6-OHDA)注射于脑右侧黑质造成偏侧PD模型,并采用中西药物(含美多巴135mg/Kg、中药为3.006g/ml)治疗,同时设立正常对照组、假手术组。用免疫组化和RT-PCR的方法观察对酪氨酸羟化酶(TH)阳性细胞及THmRNA表达的影响。结果中西药合用可以升高TH的含量,提高TH的活力,阻止或缓解6-OHDA对黑质及纹状体的损毁作用;THmRNA的表达亦明显增加,且与TH的变化趋势是一致的。结论中西药合用对TH含量的升高作用可能是通过影响TH mRNA而产生的。

家蚕酪氨酸羟化酶基因BmTh的表达及功能

酪氨酸羟化酶作为儿茶酚胺合成的限速酶,广泛存在于昆虫、哺乳动物和人类中,是其新陈代谢不可缺少的酶类。在其他昆虫中,酪氨酸羟化酶参与了黑色素的合成,并在昆虫外骨骼的硬化过程中发挥关键作用。为了研究家蚕Bombyxmori酪氨酸羟化酶基因的生理生化功能,本文对其基因结构、表达特征及功能进行了研究。基于家蚕基因组和基因芯片数据的生物信息学分析表明,BmTh位于家蚕1号染色体上,含有8个外显子,编码561个氨基酸。基因芯片数据显示在家蚕5龄第3天的头部和体壁组织中的表达量较高,RT-PCR验证结果与此一致。利用石蜡组织切片材料和RNA探针对BmTh进行表达定位,原位杂交结果显示在家蚕头部边缘和体壁上有明显的杂交信号。在幼虫发育至熟蚕时注射酪氨酸羟化酶抑制剂3-indole-L-tyrosine(3-IT),20mmol/L的浓度对幼虫几乎没有影响,50mmol/L的浓度导致幼虫变态不完全和化蛹困难,100mmol/L的浓度使幼虫致死且体色变黑。结果提示,BmTh对家蚕变态发育起重要作用,是家蚕正常发育不可缺少的关键基因。