BACKGROUND： To date, a complete protein expression profile of the midbrain substantia nigra in a mouse model of chronic Parkinson＇s disease, induced by 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine （MPTP）, does ...BACKGROUND： To date, a complete protein expression profile of the midbrain substantia nigra in a mouse model of chronic Parkinson＇s disease, induced by 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine （MPTP）, does not exist. In addition, there are no reports of analysis of differential protein expression. OBJECTIVE： To separate and evaluate MPTP-induced differential protein expression through the use of proteomics in the substantia nigra of a mouse model of chronic Parkinson＇s disease. DESIGN： Randomized controlled animal study. SETTING： Department of Neurology, the First Affiliated Hospital, Chongqing Medical University. MATERIALS： Sixteen 8-10-week old, healthy, male, C57BL mice, weighing 20-25 g, and of clean grade, were provided by the Experimental Animal Center of Chongqing Medical University. The experimental animals were disposed according to ethical criteria. MPTP was provided by Sigma Company, USA; Pdquest 2D image analysis software and gelatum/irradiance image analysis system （ChemiDoc XRS） by Bio-Rad, USA; and Voyager DE-PROMALD1-TOF-MS mass spectroscopy analyzer by AB1 Company, USA. METHODS： This study was performed in Chongqing Neurological Laboratory between November 2006 and July 2007. Mice were randomly divided into model and control groups, with 8 mice in each group. Mice in the model group were received a subcutaneous injection of MPTP （25 mg＆g）, twice a week, for five successive weeks, to establish a chronic Parkinson＇s disease model. Mice in the control group received the same volume of a subcutaneous saline injection at the same time points. Mice were sacrificed by anesthesia to rapidly obtain the midbrain for protein separation of the substantia nigra. MAIN OUTCOME MEASURES： （1） 2-ED handbook （Bio-Rad Company） was referenced for two-dimensional electrophoresis, （2） PDQUEST8,0 analytical electrophoresis pattern was adopted to evaluate differential protein expression. （3） Peptide mass finger print map and data were retrieved on http：//www.prospector.ucsf.edu to compare differential substantia nigral protein expression in the two groups. RESULTS： Two-dimensional gel electrophoresis of substantia nigra tissue indicated that there were 33 differential protein expressions between the two groups. Three new proteins were evaluated, including α -enolase, which exhibited regulated expression, tumor necrosis factor ligand superfamily member 4, and cyclin-dependent kinase inhibitor 1B. CONCLUSION： There are three proteins that exhibit differential expression in the substantia nigra- α -enolase, tumor necrosis factor ligand superfamily member 4, and cyclin-dependent kinase inhibitor 1B.展开更多
Accumulating studies suggest that neuroinflammation characterized by microglial overactivation plays a pivotal role in the pathogenesis of Parkinson’s disease.As such,inhibition of microglial overactivation might be ...Accumulating studies suggest that neuroinflammation characterized by microglial overactivation plays a pivotal role in the pathogenesis of Parkinson’s disease.As such,inhibition of microglial overactivation might be a promising treatment strategy to delay the onset or slow the progression of Parkinson’s disease.Ginsenoside Rbl,the most active ingredient of ginseng,reportedly exerts neuroprotective effects by suppressing inflammation in vitro.The present study aimed to evaluate the neuroprotective and anti-inflammatory effects of ginsenoside Rbl in a lipopolysaccharide-induced rat Parkinson’s disease model.Rats were divided into four groups.In the control group,sham-operated rats were intraperitoneally administered normal saline for 14 consecutive days.In the ginsenoside Rbl group,ginsenoside Rb1(20 mg/kg)was intraperitoneally injected for 14 consecutive days after sham surgery.In the lipopolysaccharide group,a single dose of lipopolysaccharide was unilaterally microinjected into the rat substantial nigra to establish the Parkinson’s disease model.Lipopolysaccharide-injected rats were treated with normal saline for 14 consecutive days.In the ginsenoside Rbl +lipopolysaccharide group,lipopolysaccharide was unilaterally microinjected into the rat substantial nigra.Subsequently,ginsenoside Rbl was intraperitoneally injected for 14 consecutive days.To investigate the therapeutic effects of ginsenoside Rbl,behavioral tests were performed on day 15 after lipopolysaccharide injection.We found that ginsenoside Rbl treatment remarkably reduced apomorphine-induced rotations in lipopolysaccharide-treated rats compared with the lipopolysaccharide group.To investigate the neurotoxicity of lipopolysaccharide and potential protective effect of ginsenoside Rbl,contents of dopamine and its metabolites in the striatum were measured by high-performance liquid chromatography.Compared with the lipopolysaccharide group,ginsenoside Rbl obviously attenuated the lipopolysaccharide-induced depletion of dopamine and its metabolites in the striatum.To further explore the neuroprotective effect of ginsenoside Rbl against lipopolysaccharide-induced neurotoxicity,immunohistochemistry and western blot assay of tyrosine hydroxylase were performed to evaluate dopaminergic neuron degeneration in the substantial nigra par compacta.The results showed that lipopolysaccharide injection caused a large loss of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra and a significant decrease in overall tyrosine hydroxylase expression.However,ginsenoside Rb1 noticeably reversed these changes.To investigate whether the neuroprotective effect of ginsenoside Rbl was associated with inhibition of lipopolysaccharide-induced microglial activation,we examined expression of the microglia marker Iba-1.Our results confirmed that lipopolysaccharide injection induced a significant increase in Iba-1 expression in the substantia nigra;however,ginsenoside Rbl effectively suppressed lipopolysaccharide-induced microglial overactivation.To elucidate the inhibitory mechanism of ginsenoside Rb1,we examined expression levels of inflammatory mediators(tumor necrosis factor-a,interleukin-1β,inducible nitric oxide synthase,and cyclooxygenase 2)and phosphorylation of nuclear factor kappa B signaling-related proteins(IκB,IKK)in the substantia nigra with enzyme-linked immunosorbent and western blot assays.Our results revealed that compared with the control group,phosphorylation and expression of inflammatory mediators IκB and IKK in the substantia nigra of lipopolysaccharide group rats were significantly increased;whereas,ginsenoside Rbl obviously reduced lipopolysaccharide-induced changes on the lesioned side of the substantial nigra par compacta.These findings confirm that ginsenoside Rbl can inhibit inflammation induced by lipopolysaccharide injection into the substantia nigra and protect dopaminergic neurons,which may be related to its inhibition of the nuclear factor kappa B signaling pathway.This study was approved by the Experimental Animal Ethics Committee of Shandong University of China in April 2016(approval No.KYLL-2016-0148).展开更多
L-DOPA is the primary drug used to treat Parkinson’s disease (PD) symptoms, but motor side effects limit its long term use. Previous experimental studies show that L-DOPA acts on supersensitive D1 receptors in the ba...L-DOPA is the primary drug used to treat Parkinson’s disease (PD) symptoms, but motor side effects limit its long term use. Previous experimental studies show that L-DOPA acts on supersensitive D1 receptors in the basal ganglia to induce extracellular signal-regulated kinases 1 and 2 (ERK1/2), a pair of MAP-kinase proteins that may be involved in induction of motor side effects. Since GABA is known to be intimately involved in basal ganglia function, we investigated whether elevating GABA levels via a GABA-transaminase (GABA-T) inhibitor affects the L-DOPA-induced ERK1/2 phosphorylation in the striatum and substantia nigra (SN) using a rat model of PD. Unilateral dopaminergic lesions of median forebrain bundle neurons were done using the neurotoxin 6-hydroxydopamine. Rats were prescreened for the extent of the lesion by apomorphine-induced rotation test. Lesioned rats were treated with aminooxyacetic acid (AOAA, a GABA-T inhibitor), L-DOPA, or in combination. Immunohistochemistry of tyrosine hydroxylase (TH, a direct indicator of dopaminergic lesion), substance P (SP, an indirect marker that decreases after lesion), and phospho-ERK1/2 was done using slices at the level of striatum and SN. Unilateral dopaminergic lesioned rats, as expected, exhibited >90% TH loss and a modest SP loss in the striatum and SN. L-DOPA alone induced a 343% and 330% increase in phospho-ERK1/2 in the striatum and SN, respectively. We report here a novel finding that pretreatment with AOAA attenuated the L-DOPA induced increase in phospho-ERK1/2 by 62% and 68% in the striatum and SN, respectively, suggesting a DA-GABA-ERK1/2 link in the therapeutic and/or side effects of L-DOPA.展开更多
Parkinson’s disease (PD) is characterized by degeneration of nigrostriatal dopamine (DA) neurons. The primary drug used to treat PD symptoms is L-DOPA, but side effects such as dyskinesias limit its use. Previous fin...Parkinson’s disease (PD) is characterized by degeneration of nigrostriatal dopamine (DA) neurons. The primary drug used to treat PD symptoms is L-DOPA, but side effects such as dyskinesias limit its use. Previous findings show that L-DOPA treatment induces extracellular signal-regulated kinase (ERK1/2), a MAP-kinase protein. γ-aminobutyric acid (GABA) is intimately involved in basal ganglia function. Our previous study using a unilaterally lesioned rat model of PD indicated that elevating GABA levels by GABA transaminase inhibitor, aminooxyacetic acid significantly attenuated L-DOPA-induced ERK phosphorylation in the striatum and substantia nigra (SN). The aim of the present study was to assess the role of GABA-A and GABA-B receptor by using a selective agonists, muscimol and baclofen respectively, on L-DOPA-induced ERK phosphorylation in the striatum and SN. Unilaterally 6-OHDA-lesioned rats were prescreened by apomorphine induced rotation test for the extent of DA loss. Lesioned rats were treated with L-DOPA alone or after muscimol or baclofen pretreatment. Appropriate control groups were used. Phospho-ERK levels, tyrosine hydroxylase (to ascertain DA loss) and substance P (an indirect marker for DA loss) levels were assessed by immunohistochemistry using coronal slices at the level of striatum and SN. L-DOPA administration induced a robust increase (>300%) in phospho-ERK1/2 levels in the striatum and SN. Muscimol as well as baclofen pretreatment attenuated the L-DOPA-induced increase in phospho-ERK1/2 levels by >60% in the striatum and SN. Muscimol and baclofen pretreatment also greatly reduced the number of L-DOPA induced phospho-ERK1/2 stained cells in the striatum as well as the contralateral rotational behavior. The present data taken together with our previous study indicate that the L-DOPA induced increase in ERK1/2 is attenuated by GABA via a GABA-A and GABA-B receptor linked mechanism. The study provides further insight into a dopamine-GABA-ERK interaction in the therapeutic and/or side effects of L-DOPA in the basal ganglia.展开更多
Previous studies have shown that neural stem cell transplantation has the potential to treat Parkinson’s disease,but its specific mechanism of action is still unclear.Stromal cell-derived factor-1 and its receptor,ch...Previous studies have shown that neural stem cell transplantation has the potential to treat Parkinson’s disease,but its specific mechanism of action is still unclear.Stromal cell-derived factor-1 and its receptor,chemokine receptor 4(CXCR4),are important regulators of cell migration.We speculated that the CXCR4/stromal cell-derived factor 1 axis may be involved in the therapeutic effect of neural stem cell transplantation in the treatment of Parkinson’s disease.A Parkinson’s disease rat model was injected with 6-hydroxydopamine via the right ascending nigrostriatal dopaminergic pathway,and then treated with 5μL of neural stem cell suspension(1.5×104/L)in the right substantia nigra.Rats were intraperitoneally injected once daily for 3 days with 1.25 mL/kg of the CXCR4 antagonist AMD3100 to observe changes after neural stem cell transplantation.Parkinson-like behavior in rats was detected using apomorphine-induced rotation.Immunofluorescence staining was used to determine the immunoreactivity of tyrosine hydroxylase,CXCR4,and stromal cell-derived factor-1 in the brain.Using quantitative real-time polymerase chain reaction,the mRNA expression of stromal cell-derived factor-1 and CXCR4 in the right substantia nigra were measured.In addition,western blot assays were performed to analyze the protein expression of stromal cell-derived factor-1 and CXCR4.Our results demonstrated that neural stem cell transplantation noticeably reduced apomorphine-induced rotation,increased the mRNA and protein expression of stromal cell-derived factor-1 and CXCR4 in the right substantia nigra,and enhanced the immunoreactivity of tyrosine hydroxylase,CXCR4,and stromal cell-derived factor-1 in the brain.Injection of AMD3100 inhibited the aforementioned effects.These findings suggest that the stromal cell-derived factor-1/CXCR4 axis may play a significant role in the therapeutic effect of neural stem cell transplantation in a rat model of Parkinson’s disease.This study was approved by the Animal Care and Use Committee of Kunming Medical University,China(approval No.SYXKK2015-0002)on April 1,2014.展开更多
To prevent and treat Parkinson＇s disease in its early stages,it is essential to be able to detect the degree of early dopaminergic neuron degeneration.Dopamine transporters（DAT） in the striatum regulate synaptic do...To prevent and treat Parkinson＇s disease in its early stages,it is essential to be able to detect the degree of early dopaminergic neuron degeneration.Dopamine transporters（DAT） in the striatum regulate synaptic dopamine levels,and striatal ^99mTc-TRODAT-1 single-photon emission computed tomography（-SPECT） imaging is a marker for presynaptic neuronal degeneration.However,the association between the degree of dopaminergic degeneration and in vivo ^99mTc-TRODAT-1 SPECT imaging is unknown.Therefore,this study investigated the association between the degree of 6-hydroxydopamine（6-OHDA）-induced dopaminergic degeneration and DAT imaging using^99mTc-TRODAT-1 SPECT in rats.Different degrees of nigrostriatal dopamine depletion were generated by injecting different doses of 6-OHDA（2,4,and 8 μg） into the right medial forebrain bundle.The degree of nigrostriatal dopaminergic neuron degeneration was assessed by rotational behavior and immunohistochemical staining.The results showed that striatal ^99mTc-TRODAT-1 binding was significantly diminished both in the ipsilateral and the contralateral sides in the 4 and 8 μg 6-OHDA groups,and that DAT ^99mTc-TRODAT-1 binding in the ipsilateral striatum showed a high correlation to apomorphine-induced rotations at 8 weeks post-lesion（r = –0.887,P 〈 0.01）.There were significant correlations between DAT ^99mTc-TRODAT-1 binding in the ipsilateral striatum and the amount of tyrosine hydroxylase immunoreactive neurons in the ipsilateral substantia nigra in the 2,4,and 8 μg 6-OHDA groups at 8 weeks post-lesion（r = 0.899,P 〈 0.01）.These findings indicate that striatal DAT imaging using ^99mTc-TRODAT-1 is a useful technique for evaluating the severity of dopaminergic degeneration.展开更多
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 Parkin...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.展开更多
基金the National Natural Science Foundation of China, No. 30370499
文摘BACKGROUND： To date, a complete protein expression profile of the midbrain substantia nigra in a mouse model of chronic Parkinson＇s disease, induced by 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine （MPTP）, does not exist. In addition, there are no reports of analysis of differential protein expression. OBJECTIVE： To separate and evaluate MPTP-induced differential protein expression through the use of proteomics in the substantia nigra of a mouse model of chronic Parkinson＇s disease. DESIGN： Randomized controlled animal study. SETTING： Department of Neurology, the First Affiliated Hospital, Chongqing Medical University. MATERIALS： Sixteen 8-10-week old, healthy, male, C57BL mice, weighing 20-25 g, and of clean grade, were provided by the Experimental Animal Center of Chongqing Medical University. The experimental animals were disposed according to ethical criteria. MPTP was provided by Sigma Company, USA; Pdquest 2D image analysis software and gelatum/irradiance image analysis system （ChemiDoc XRS） by Bio-Rad, USA; and Voyager DE-PROMALD1-TOF-MS mass spectroscopy analyzer by AB1 Company, USA. METHODS： This study was performed in Chongqing Neurological Laboratory between November 2006 and July 2007. Mice were randomly divided into model and control groups, with 8 mice in each group. Mice in the model group were received a subcutaneous injection of MPTP （25 mg＆g）, twice a week, for five successive weeks, to establish a chronic Parkinson＇s disease model. Mice in the control group received the same volume of a subcutaneous saline injection at the same time points. Mice were sacrificed by anesthesia to rapidly obtain the midbrain for protein separation of the substantia nigra. MAIN OUTCOME MEASURES： （1） 2-ED handbook （Bio-Rad Company） was referenced for two-dimensional electrophoresis, （2） PDQUEST8,0 analytical electrophoresis pattern was adopted to evaluate differential protein expression. （3） Peptide mass finger print map and data were retrieved on http：//www.prospector.ucsf.edu to compare differential substantia nigral protein expression in the two groups. RESULTS： Two-dimensional gel electrophoresis of substantia nigra tissue indicated that there were 33 differential protein expressions between the two groups. Three new proteins were evaluated, including α -enolase, which exhibited regulated expression, tumor necrosis factor ligand superfamily member 4, and cyclin-dependent kinase inhibitor 1B. CONCLUSION： There are three proteins that exhibit differential expression in the substantia nigra- α -enolase, tumor necrosis factor ligand superfamily member 4, and cyclin-dependent kinase inhibitor 1B.
基金supported by the Medical and Health Technology Development Plan of Shandong Province of China,No.2011HD009(to AHW)the Chinese Medicine Science and Technology Development Plan Project of Shandong Province of China,No.2017-163(to AHW)+1 种基金the Natural Science Foundation of Shandong Province of China,No.ZR2016HP23(to AHW)the Science and Technology Development Plan Project of Taian City of China,No.2017NS0151(to XCS)
文摘Accumulating studies suggest that neuroinflammation characterized by microglial overactivation plays a pivotal role in the pathogenesis of Parkinson’s disease.As such,inhibition of microglial overactivation might be a promising treatment strategy to delay the onset or slow the progression of Parkinson’s disease.Ginsenoside Rbl,the most active ingredient of ginseng,reportedly exerts neuroprotective effects by suppressing inflammation in vitro.The present study aimed to evaluate the neuroprotective and anti-inflammatory effects of ginsenoside Rbl in a lipopolysaccharide-induced rat Parkinson’s disease model.Rats were divided into four groups.In the control group,sham-operated rats were intraperitoneally administered normal saline for 14 consecutive days.In the ginsenoside Rbl group,ginsenoside Rb1(20 mg/kg)was intraperitoneally injected for 14 consecutive days after sham surgery.In the lipopolysaccharide group,a single dose of lipopolysaccharide was unilaterally microinjected into the rat substantial nigra to establish the Parkinson’s disease model.Lipopolysaccharide-injected rats were treated with normal saline for 14 consecutive days.In the ginsenoside Rbl +lipopolysaccharide group,lipopolysaccharide was unilaterally microinjected into the rat substantial nigra.Subsequently,ginsenoside Rbl was intraperitoneally injected for 14 consecutive days.To investigate the therapeutic effects of ginsenoside Rbl,behavioral tests were performed on day 15 after lipopolysaccharide injection.We found that ginsenoside Rbl treatment remarkably reduced apomorphine-induced rotations in lipopolysaccharide-treated rats compared with the lipopolysaccharide group.To investigate the neurotoxicity of lipopolysaccharide and potential protective effect of ginsenoside Rbl,contents of dopamine and its metabolites in the striatum were measured by high-performance liquid chromatography.Compared with the lipopolysaccharide group,ginsenoside Rbl obviously attenuated the lipopolysaccharide-induced depletion of dopamine and its metabolites in the striatum.To further explore the neuroprotective effect of ginsenoside Rbl against lipopolysaccharide-induced neurotoxicity,immunohistochemistry and western blot assay of tyrosine hydroxylase were performed to evaluate dopaminergic neuron degeneration in the substantial nigra par compacta.The results showed that lipopolysaccharide injection caused a large loss of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra and a significant decrease in overall tyrosine hydroxylase expression.However,ginsenoside Rb1 noticeably reversed these changes.To investigate whether the neuroprotective effect of ginsenoside Rbl was associated with inhibition of lipopolysaccharide-induced microglial activation,we examined expression of the microglia marker Iba-1.Our results confirmed that lipopolysaccharide injection induced a significant increase in Iba-1 expression in the substantia nigra;however,ginsenoside Rbl effectively suppressed lipopolysaccharide-induced microglial overactivation.To elucidate the inhibitory mechanism of ginsenoside Rb1,we examined expression levels of inflammatory mediators(tumor necrosis factor-a,interleukin-1β,inducible nitric oxide synthase,and cyclooxygenase 2)and phosphorylation of nuclear factor kappa B signaling-related proteins(IκB,IKK)in the substantia nigra with enzyme-linked immunosorbent and western blot assays.Our results revealed that compared with the control group,phosphorylation and expression of inflammatory mediators IκB and IKK in the substantia nigra of lipopolysaccharide group rats were significantly increased;whereas,ginsenoside Rbl obviously reduced lipopolysaccharide-induced changes on the lesioned side of the substantial nigra par compacta.These findings confirm that ginsenoside Rbl can inhibit inflammation induced by lipopolysaccharide injection into the substantia nigra and protect dopaminergic neurons,which may be related to its inhibition of the nuclear factor kappa B signaling pathway.This study was approved by the Experimental Animal Ethics Committee of Shandong University of China in April 2016(approval No.KYLL-2016-0148).
文摘L-DOPA is the primary drug used to treat Parkinson’s disease (PD) symptoms, but motor side effects limit its long term use. Previous experimental studies show that L-DOPA acts on supersensitive D1 receptors in the basal ganglia to induce extracellular signal-regulated kinases 1 and 2 (ERK1/2), a pair of MAP-kinase proteins that may be involved in induction of motor side effects. Since GABA is known to be intimately involved in basal ganglia function, we investigated whether elevating GABA levels via a GABA-transaminase (GABA-T) inhibitor affects the L-DOPA-induced ERK1/2 phosphorylation in the striatum and substantia nigra (SN) using a rat model of PD. Unilateral dopaminergic lesions of median forebrain bundle neurons were done using the neurotoxin 6-hydroxydopamine. Rats were prescreened for the extent of the lesion by apomorphine-induced rotation test. Lesioned rats were treated with aminooxyacetic acid (AOAA, a GABA-T inhibitor), L-DOPA, or in combination. Immunohistochemistry of tyrosine hydroxylase (TH, a direct indicator of dopaminergic lesion), substance P (SP, an indirect marker that decreases after lesion), and phospho-ERK1/2 was done using slices at the level of striatum and SN. Unilateral dopaminergic lesioned rats, as expected, exhibited >90% TH loss and a modest SP loss in the striatum and SN. L-DOPA alone induced a 343% and 330% increase in phospho-ERK1/2 in the striatum and SN, respectively. We report here a novel finding that pretreatment with AOAA attenuated the L-DOPA induced increase in phospho-ERK1/2 by 62% and 68% in the striatum and SN, respectively, suggesting a DA-GABA-ERK1/2 link in the therapeutic and/or side effects of L-DOPA.
文摘Parkinson’s disease (PD) is characterized by degeneration of nigrostriatal dopamine (DA) neurons. The primary drug used to treat PD symptoms is L-DOPA, but side effects such as dyskinesias limit its use. Previous findings show that L-DOPA treatment induces extracellular signal-regulated kinase (ERK1/2), a MAP-kinase protein. γ-aminobutyric acid (GABA) is intimately involved in basal ganglia function. Our previous study using a unilaterally lesioned rat model of PD indicated that elevating GABA levels by GABA transaminase inhibitor, aminooxyacetic acid significantly attenuated L-DOPA-induced ERK phosphorylation in the striatum and substantia nigra (SN). The aim of the present study was to assess the role of GABA-A and GABA-B receptor by using a selective agonists, muscimol and baclofen respectively, on L-DOPA-induced ERK phosphorylation in the striatum and SN. Unilaterally 6-OHDA-lesioned rats were prescreened by apomorphine induced rotation test for the extent of DA loss. Lesioned rats were treated with L-DOPA alone or after muscimol or baclofen pretreatment. Appropriate control groups were used. Phospho-ERK levels, tyrosine hydroxylase (to ascertain DA loss) and substance P (an indirect marker for DA loss) levels were assessed by immunohistochemistry using coronal slices at the level of striatum and SN. L-DOPA administration induced a robust increase (>300%) in phospho-ERK1/2 levels in the striatum and SN. Muscimol as well as baclofen pretreatment attenuated the L-DOPA-induced increase in phospho-ERK1/2 levels by >60% in the striatum and SN. Muscimol and baclofen pretreatment also greatly reduced the number of L-DOPA induced phospho-ERK1/2 stained cells in the striatum as well as the contralateral rotational behavior. The present data taken together with our previous study indicate that the L-DOPA induced increase in ERK1/2 is attenuated by GABA via a GABA-A and GABA-B receptor linked mechanism. The study provides further insight into a dopamine-GABA-ERK interaction in the therapeutic and/or side effects of L-DOPA in the basal ganglia.
基金This work was supported by the National Natural Science Foundation of China (No. 30271441) Key Project of Shandong Educational Committee (J01 K03) and Qingdao Municipal Science & Technology Commission (02-1-KJ-YJ-49).
基金supported by the National Natural Science Foundation of China,No.81241126(to XLD)and 81360197(to XLD)a grant from the Department of Science and Technology of Kunming Medical University in China,No.2013C227(to XLD)the Joint Special Fund for the Department of Science and Technology of Kunming Medical University in China,No.2014FB041(to XBS)
文摘Previous studies have shown that neural stem cell transplantation has the potential to treat Parkinson’s disease,but its specific mechanism of action is still unclear.Stromal cell-derived factor-1 and its receptor,chemokine receptor 4(CXCR4),are important regulators of cell migration.We speculated that the CXCR4/stromal cell-derived factor 1 axis may be involved in the therapeutic effect of neural stem cell transplantation in the treatment of Parkinson’s disease.A Parkinson’s disease rat model was injected with 6-hydroxydopamine via the right ascending nigrostriatal dopaminergic pathway,and then treated with 5μL of neural stem cell suspension(1.5×104/L)in the right substantia nigra.Rats were intraperitoneally injected once daily for 3 days with 1.25 mL/kg of the CXCR4 antagonist AMD3100 to observe changes after neural stem cell transplantation.Parkinson-like behavior in rats was detected using apomorphine-induced rotation.Immunofluorescence staining was used to determine the immunoreactivity of tyrosine hydroxylase,CXCR4,and stromal cell-derived factor-1 in the brain.Using quantitative real-time polymerase chain reaction,the mRNA expression of stromal cell-derived factor-1 and CXCR4 in the right substantia nigra were measured.In addition,western blot assays were performed to analyze the protein expression of stromal cell-derived factor-1 and CXCR4.Our results demonstrated that neural stem cell transplantation noticeably reduced apomorphine-induced rotation,increased the mRNA and protein expression of stromal cell-derived factor-1 and CXCR4 in the right substantia nigra,and enhanced the immunoreactivity of tyrosine hydroxylase,CXCR4,and stromal cell-derived factor-1 in the brain.Injection of AMD3100 inhibited the aforementioned effects.These findings suggest that the stromal cell-derived factor-1/CXCR4 axis may play a significant role in the therapeutic effect of neural stem cell transplantation in a rat model of Parkinson’s disease.This study was approved by the Animal Care and Use Committee of Kunming Medical University,China(approval No.SYXKK2015-0002)on April 1,2014.
基金supported by the National Natural Science Foundation of China,No.81571250
文摘To prevent and treat Parkinson＇s disease in its early stages,it is essential to be able to detect the degree of early dopaminergic neuron degeneration.Dopamine transporters（DAT） in the striatum regulate synaptic dopamine levels,and striatal ^99mTc-TRODAT-1 single-photon emission computed tomography（-SPECT） imaging is a marker for presynaptic neuronal degeneration.However,the association between the degree of dopaminergic degeneration and in vivo ^99mTc-TRODAT-1 SPECT imaging is unknown.Therefore,this study investigated the association between the degree of 6-hydroxydopamine（6-OHDA）-induced dopaminergic degeneration and DAT imaging using^99mTc-TRODAT-1 SPECT in rats.Different degrees of nigrostriatal dopamine depletion were generated by injecting different doses of 6-OHDA（2,4,and 8 μg） into the right medial forebrain bundle.The degree of nigrostriatal dopaminergic neuron degeneration was assessed by rotational behavior and immunohistochemical staining.The results showed that striatal ^99mTc-TRODAT-1 binding was significantly diminished both in the ipsilateral and the contralateral sides in the 4 and 8 μg 6-OHDA groups,and that DAT ^99mTc-TRODAT-1 binding in the ipsilateral striatum showed a high correlation to apomorphine-induced rotations at 8 weeks post-lesion（r = –0.887,P 〈 0.01）.There were significant correlations between DAT ^99mTc-TRODAT-1 binding in the ipsilateral striatum and the amount of tyrosine hydroxylase immunoreactive neurons in the ipsilateral substantia nigra in the 2,4,and 8 μg 6-OHDA groups at 8 weeks post-lesion（r = 0.899,P 〈 0.01）.These findings indicate that striatal DAT imaging using ^99mTc-TRODAT-1 is a useful technique for evaluating the severity of dopaminergic degeneration.
基金supported by the National Natural Science Foundation of China,No. 81971006 (to DSG)。
文摘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.
