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Parkinson's disease (PD) is the second most common neurodegenerative disease and is typically associated with progressive motor and non-motor dysfunctions. Currently, dopamine replacement therapy is mainly used to relieve the motor symptoms, while its long-term application can lead to various complications and does not cure the disease. Numerous studies have demonstrated that many brain-gut peptides have neuroprotective effects in vivo and in vitro, and may be a promising treatment for PD. In recent years, some progress has been made in studies on the neuroprotective effects of some newly-discovered brain-gut peptides, such as glucagon-like peptide 1, pituitary adenylate cyclase activating polypeptide, nesfatin-1, and ghrelin. However, there is still no systematic review on the neuroprotective effects common to these peptides. Thus, here we review the neuroprotective effects and the associated mechanisms of these four peptides, as well as other brain-gut peptides related to PD, in the hope of providing new ideas for the treatment of PD and related clinical research.
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The pathogenesis of the second major neurodegenerative disorder, Parkinson's disease (PD), is closely associated with the dysfunction of potassium (K) channels. Therefore, PD is also considered to be an ion channel disease or neuronal channelopathy. Mounting evidence has shown that K channels play crucial roles in the regulations of neurotransmitter release, neuronal excitability, and cell volume. Inhibition of K channels enhances the spontaneous firing frequency of nigral dopamine (DA) neurons, induces a transition from tonic firing to burst discharge, and promotes the release of DA in the striatum. Recently, three K channels have been identified to protect DA neurons and to improve the motor and non-motor symptoms in PD animal models: small conductance (SK) channels, A-type K channels, and K7/KCNQ channels. In this review, we summarize the physiological and pharmacological effects of the three K channels. We also describe in detail the laboratory investigations regarding K channels as a potential therapeutic target for PD.
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Animals , Humans , Parkinson Disease , Metabolism , Potassium Channels , MetabolismABSTRACT
Objective To modify a classic two-vessel occlusion (2VO) modeling method in order to decrease the systematic errors in the behavioral experiments such as Morris water maze.Methods Thirty-two adult male Wistar rats were randomly allocated into classic 2VO model,modified model,sham operation and sham ligation groups (n =8 in each group).Only the bilateral common carotid arteries were ligated in the classic 2VO model group; the common carotid arteries were clipped intermittently,and the origins of pterygopalatine arteries of the internal carotid arteries were high selectively ligated in the modified model group; the common carotid arteries were only ligated intermittently in the sham ligation group; and only the common carotid arteries and the upper segment of pterygopalatine artery branches were separated in the sham operation group.The rat behavior was evaluated using the pupillary light reflex,Morris water maze and eight-arm radial maze.HE staining was used to observe the histological changes.Results The Morris water maze escape latency (F =72.169 - 163.102,all P ＜ 0.001) and the number of reference memory errors of eight-arm radial maze (F =33.515-74.726,all P ＜0.001) in the modified model and the classic 2VO model groups were longer and higher than those in the sham operation group.The pupillary light reflex of the rats was lost in the classic 2VO model group and the pupillary light reflex of the rats was normal in other groups.The reaching platform time in the classic 2VO model group was significantly longer than that in the modified model and sham operation groups (P ＜0.001).The percentage of target quadrant dwell time was also decreased significantly (at day 7 after procedure:F =13.770,P ＜0.001 ; at day 90 after procedure:F =14.780,P ＜0.001).HE staining showed pathological changes such as the cells decrease in hippocampal CA1 region and leukoaraiosis in the modified model and the classic 2VO model groups.In addition,there were more vacuole-like changes in the rat optic nerve region in the classic 2VO model group,while there were no such changes in the modified model group.Conclusions Establishing vascular dementia model with permanent occlusion of bilateral internal carotid arteries after intermittent occlusion of bilateral carotid arteries could avoid severe visual impairment in rats.In the Morris water maze and eight-arm maze test,the modified model rats showed significant decrease in learning and memory abilities and had hippocampal damage.
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Objective To study the methylation status of secreted frizzled-related protein (SFRP) 1 and SFRP2 genes in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) and the relationship between the methylation status of the two genes and the development of HCC.Methods Using methylation-specific polymerase chain reaction (MSP) to detect methylation status of SFRP1 and SFRP2 genes of 45 specimens of HCC tissue and adjacent non-tumorous liver tissue from HCC patients during operations,and 6 normal liver tissues from patients with cholecystolithiasis or hepatic hemangiomas. The data were analyzed by chi-square test and Fisher exact test. Results SFRP1 gene methylation was detected in 28 HCC tissues and 16 adjacent non-tumorous liver tissues,accounted for 62.2% and 35.6%,respectively;and SFRP2 gene methylation was detected in 23 HCC tissues and 13 adjacent non-tumorous liver tissues,accounted for 51.1% and 28.9%,respectively;while no methylation was detected in 6 samples of normal liver tissues. There was no significant difference between the methylation of SFRP1 and SFRP2 genes in HCC tissues and gender,age,HBV serum markers,types of adjacent non-tumorous liver tissues,metastasis and pathological stage (P＞0.05).The abnormal methylation status between SFRP1 and SFRP2 genes was linear correlated in HCC tissues (r=0.381,P=0.01).Conclusion Hypermethylation of SFRP1 and SFRP2 genes frequently occurs in HBV-related HCC,which may be an important molecular biomarker for prediction of hepatocarcinogenesis in the future.
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Objective To detect the integration of hepatitis B virus (HBV) DNA in HBVrelated human hepatocellular carcinomas (HCC). Methods Extracted DNA from the liver tissue samples and amplified by nested polymerase chain reaction (PCR) with specially designed U-base primers. According to the known genes and human Alu repeat sequences (Alu repeat) , primers were designed respectively. Integrated clones combined target HBV DNA and the adjacent cell gene sequences were established by PCR and products were sequenced by biotechnology companies.Accurate locations of HBV genes integrated in the human genomes were analyzed by national center for biotechnology information (NCBI) basic local alignment search tool (BLAST) and Map Viewer search. Results In 24 HBsAg positive HCC samples, 15 cases showed the integrations of HBV fragment. And the other 8 samples didn't show any evidence of integration. Among 14 samples with integration, forward insertions of HBV DNA into the host chromosomal DNA were found in 10 samples and reverse insertions were found in 8 samples while both forward and reverse insertions were found in 5 samples. Analysis from viral-cellular junctions suggested that the integrations were all happened with truncated viral DNA and could be in any locus of X gene. Conclusion HBV DNA integration is not distributed evenly throughout the host genome.
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Aim The present study is designed to elucidate the protective effect of Polysaccharide from Spirulina Platensis(PSP) on dopaminergic neurons of MPTP-induced Parkinsons disease model in C57BL mice.Methods C57BL mice were divided into 5 groups:control group,MPTP group,PSP 200 mg?kg-1 plus MPTP group,PSP 400 mg?kg-1 plus MPTP group,and PSP 800 mg?kg-1 plus MPTP group.Immunohistochemistry assay,RT-PCR,and HPLC-ECD were used to detect the immunoreactivity of tyrosine hydroxylase(TH) and dopamine transporters(DAT),the expression of TH mRNA and DAT mRNA in substantia nigra(SN),the content of dopamine(DA) and its metabolites,i.e.3,4-dihydroxyphenyl acetic acid(DOPAC) and homovanilic acid(HVA) in striatum(Str).Results The result showed that,compared with control group,the TH and DAT immunoreactive stain in MPTP group was significantly decreased(P
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Objective To construct a vector carrying tyrosine hydroxylase (TH) and glial cell line-derived neurotrophic factor (GDNF) in order to establish a new gene therapy method in Parkinson's disease. Methods Human TH gene fragment from the plasmid pWAV2-TH was cloned into pIRES to construct pIRES-TH. The mouse GDNF gene, amplified by PCR was inserted into pIRES-TH to construct pIRES-TH-GDNF. Restriction analysis and nucleotide sequencing were used to confirm the structure of pIRES-TH-GDNF. Then MES23.5 cells were transfected with this eukaryon vector using Lipofectamine TM2000. The expression of TH and GDNF in mRNA and protein levels were detected by RT-PCR and immunofluorescence after G418 selection. Results The 2 objective fragments were inserted into pIRES correctly. RT-PCR and immunofluorescence results showed that TH and GDNF were highly expressed in MES23.5 cells. Conclusion The plasmid pIRES-TH-GDNF is constructed successfully and can express TH and GDNF in vitro.