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Montaño-Rodriguez AR, Schorling T, Andressoo JO. Striatal GDNF Neurons Chemoattract RET-Positive Dopamine Axons at Seven Times Farther Distance Than Medium Spiny Neurons. Cells 2024; 13:1059. [PMID: 38920687 PMCID: PMC11202212 DOI: 10.3390/cells13121059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/08/2024] [Accepted: 06/12/2024] [Indexed: 06/27/2024] Open
Abstract
Glial cell line-derived neurotrophic factor (GDNF) is among the strongest dopamine neuron function- and survival-promoting factors known. Due to this reason, it has clinical relevance in dopamine disorders such as Parkinson's disease and schizophrenia. In the striatum, GDNF is exclusively expressed in interneurons, which make up only about 0.6% of striatal cells. Despite clinical significance, histological analysis of striatal GDNF system arborization and relevance to incoming dopamine axons, which bear its receptor RET, has remained enigmatic. This is mainly due to the lack of antibodies able to visualize GDNF- and RET-positive cellular processes; here, we overcome this problem by using knock-in marker alleles. We find that GDNF neurons chemoattract RET+ axons at least seven times farther in distance than medium spiny neurons (MSNs), which make up 95% of striatal neurons. Furthermore, we provide evidence that tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis, is enriched towards GDNF neurons in the dopamine axons. Finally, we find that GDNF neuron arborizations occupy approximately only twelve times less striatal volume than 135 times more abundant MSNs. Collectively, our results improve our understanding of how endogenous GDNF affects striatal dopamine system function.
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Affiliation(s)
- Ana Rosa Montaño-Rodriguez
- Department of Pharmacology, Faculty of Medicine, Helsinki Institute of Life Science, University of Helsinki, 00290 Helsinki, Finland; (A.R.M.-R.); (T.S.)
| | - Tabea Schorling
- Department of Pharmacology, Faculty of Medicine, Helsinki Institute of Life Science, University of Helsinki, 00290 Helsinki, Finland; (A.R.M.-R.); (T.S.)
| | - Jaan-Olle Andressoo
- Department of Pharmacology, Faculty of Medicine, Helsinki Institute of Life Science, University of Helsinki, 00290 Helsinki, Finland; (A.R.M.-R.); (T.S.)
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society (NVS), Karolinska Institutet, 17177 Stockholm, Sweden
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Xu W, Ding Z, Song Z, Wang J, Zhang J, Zou W. Overexpression of GDNF in Spinal Cord Attenuates Morphine Analgesic Tolerance in Rats with Bone Cancer Pain. Brain Sci 2022; 12:brainsci12091188. [PMID: 36138924 PMCID: PMC9496664 DOI: 10.3390/brainsci12091188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/22/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
Bone cancer pain (BCP) is one of the typical and distressing symptoms in cancer patients. Morphine is a widely used analgesic drug for BCP; however, long-term morphine administration will lead to analgesic tolerance. Our previous study indicated that spinal glial cell line-derived neurotrophic factor (GDNF) exerts analgesic effects in rats with BCP. In this study, BCP was established by inoculated Walker 256 carcinoma cells into rat tibias, while morphine tolerance (MT) was induced by intrathecally injecting morphine twice daily from the 9th to 15th postoperative day (POD) in BCP rats. The BCP rats developed mechanical and thermal hyperalgesia on POD 5 and it lasted to POD 15. The analgesic effect of morphine was decreased after repeat administration. Western blots and immunochemistry tests showed that GDNF was gradually decreased in the spinal cord after the development of MT in rats with BCP, and GDNF was colocalized with the μ opioid receptor (MOR) in the superficial laminate of the spinal cords. The overexpression of GDNF by lentivirus significantly attenuated MT, and restored the expression of MOR in the spinal cord. In summary, our results suggest that the reduction of GDNF expression participated in the development of MT in rats with BCP and could be a promising therapeutic option for BCP.
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Affiliation(s)
- Wei Xu
- Department of Anesthesiology, The Maternal and Child Health Hospital of Hunan Province, Changsha 410010, China
| | - Zhuofeng Ding
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Zongbin Song
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Jian Wang
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Jie Zhang
- Department of Anesthesiology, The Maternal and Child Health Hospital of Hunan Province, Changsha 410010, China
- Correspondence: ; Tel.: +86-13787246060
| | - Wangyuan Zou
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha 410008, China
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Inactivation of the GATA Cofactor ZFPM1 Results in Abnormal Development of Dorsal Raphe Serotonergic Neuron Subtypes and Increased Anxiety-Like Behavior. J Neurosci 2020; 40:8669-8682. [PMID: 33046550 DOI: 10.1523/jneurosci.2252-19.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 09/17/2020] [Accepted: 09/25/2020] [Indexed: 12/14/2022] Open
Abstract
Serotonergic neurons in the dorsal raphe (DR) nucleus are associated with several psychiatric disorders including depression and anxiety disorders, which often have a neurodevelopmental component. During embryonic development, GATA transcription factors GATA2 and GATA3 operate as serotonergic neuron fate selectors and regulate the differentiation of serotonergic neuron subtypes of DR. Here, we analyzed the requirement of GATA cofactor ZFPM1 in the development of serotonergic neurons using Zfpm1 conditional mouse mutants. Our results demonstrated that, unlike the GATA factors, ZFPM1 is not essential for the early differentiation of serotonergic precursors in the embryonic rhombomere 1. In contrast, in perinatal and adult male and female Zfpm1 mutants, a lateral subpopulation of DR neurons (ventrolateral part of the DR) was lost, whereas the number of serotonergic neurons in a medial subpopulation (dorsal region of the medial DR) had increased. Additionally, adult male and female Zfpm1 mutants had reduced serotonin concentration in rostral brain areas and displayed increased anxiety-like behavior. Interestingly, female Zfpm1 mutant mice showed elevated contextual fear memory that was abolished with chronic fluoxetine treatment. Altogether, these results demonstrate the importance of ZFPM1 for the development of DR serotonergic neuron subtypes involved in mood regulation. It also suggests that the neuronal fate selector function of GATAs is modulated by their cofactors to refine the differentiation of neuronal subtypes.SIGNIFICANCE STATEMENT Predisposition to anxiety disorders has both a neurodevelopmental and a genetic basis. One of the brainstem nuclei involved in the regulation of anxiety is the dorsal raphe, which contains different subtypes of serotonergic neurons. We show that inactivation of a transcriptional cofactor ZFPM1 in mice results in a developmental failure of laterally located dorsal raphe serotonergic neurons and changes in serotonergic innervation of rostral brain regions. This leads to elevated anxiety-like behavior and contextual fear memory, alleviated by chronic fluoxetine treatment. Our work contributes to understanding the neurodevelopmental mechanisms that may be disturbed in the anxiety disorder.
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MANF Ablation Causes Prolonged Activation of the UPR without Neurodegeneration in the Mouse Midbrain Dopamine System. eNeuro 2020; 7:ENEURO.0477-19.2019. [PMID: 32005751 PMCID: PMC7053174 DOI: 10.1523/eneuro.0477-19.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 01/08/2023] Open
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER) localized protein that regulates ER homeostasis and unfolded protein response (UPR). The biology of endogenous MANF in the mammalian brain is unknown and therefore we studied the brain phenotype of MANF-deficient female and male mice at different ages focusing on the midbrain dopamine system and cortical neurons. We show that a lack of MANF from the brain led to the chronic activation of UPR by upregulation of the endoribonuclease activity of the inositol-requiring enzyme 1α (IRE1α) pathway. Furthermore, in the aged MANF-deficient mouse brain in addition the protein kinase-like ER kinase (PERK) and activating transcription factor 6 (ATF6) branches of the UPR pathways were activated. Neuronal loss in neurodegenerative diseases has been associated with chronic ER stress. In our mouse model, increased UPR activation did not lead to neuronal cell loss in the substantia nigra (SN), decrease of striatal dopamine or behavioral changes of MANF-deficient mice. However, cortical neurons lacking MANF were more vulnerable to chemical induction of additional ER stress in vitro. We conclude that embryonic neuronal deletion of MANF does not cause the loss of midbrain dopamine neurons in mice. However, endogenous MANF is needed for maintenance of neuronal ER homeostasis both in vivo and in vitro.
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Lindahl M, Chalazonitis A, Palm E, Pakarinen E, Danilova T, Pham TD, Setlik W, Rao M, Võikar V, Huotari J, Kopra J, Andressoo JO, Piepponen PT, Airavaara M, Panhelainen A, Gershon MD, Saarma M. Cerebral dopamine neurotrophic factor-deficiency leads to degeneration of enteric neurons and altered brain dopamine neuronal function in mice. Neurobiol Dis 2019; 134:104696. [PMID: 31783118 PMCID: PMC7000201 DOI: 10.1016/j.nbd.2019.104696] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/07/2019] [Accepted: 11/24/2019] [Indexed: 12/13/2022] Open
Abstract
Cerebral dopamine neurotrophic factor (CDNF) is neuroprotective for nigrostriatal dopamine neurons and restores dopaminergic function in animal models of Parkinson’s disease (PD). To understand the role of CDNF in mammals, we generated CDNF knockout mice (Cdnf−/−), which are viable, fertile, and have a normal life-span. Surprisingly, an age-dependent loss of enteric neurons occurs selectively in the submucosal but not in the myenteric plexus. This neuronal loss is a consequence not of increased apoptosis but of neurodegeneration and autophagy. Quantitatively, the neurodegeneration and autophagy found in the submucosal plexus in duodenum, ileum and colon of the Cdnf−/− mouse are much greater than in those of Cdnf+/+ mice. The selective vulnerability of submucosal neurons to the absence of CDNF is reminiscent of the tendency of pathological abnormalities to occur in the submucosal plexus in biopsies of patients with PD. In contrast, the number of substantia nigra dopamine neurons and dopamine and its metabolite concentrations in the striatum are unaltered in Cdnf−/− mice; however, there is an age-dependent deficit in the function of the dopamine system in Cdnf−/− male mice analyzed. This is observed as D-amphetamine-induced hyperactivity, aberrant dopamine transporter function, and as increased D-amphetamine-induced dopamine release demonstrating that dopaminergic axon terminal function in the striatum of the Cdnf−/− mouse brain is altered. The deficiencies of Cdnf−/− mice, therefore, are reminiscent of those seen in early stages of Parkinson’s disease.
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Affiliation(s)
- Maria Lindahl
- Institute of Biotechnology, HiLIFE Unit, Viikinkaari 5D, FI-00014, University of Helsinki, Finland.
| | | | - Erik Palm
- Institute of Biotechnology, HiLIFE Unit, Viikinkaari 5D, FI-00014, University of Helsinki, Finland
| | - Emmi Pakarinen
- Institute of Biotechnology, HiLIFE Unit, Viikinkaari 5D, FI-00014, University of Helsinki, Finland
| | - Tatiana Danilova
- Institute of Biotechnology, HiLIFE Unit, Viikinkaari 5D, FI-00014, University of Helsinki, Finland
| | - Tuan D Pham
- Department of Pathology & Cell Biology, Columbia University, NY, New York, USA
| | - Wanda Setlik
- Department of Pathology & Cell Biology, Columbia University, NY, New York, USA
| | - Meenakshi Rao
- Department of Pathology & Cell Biology, Columbia University, NY, New York, USA
| | - Vootele Võikar
- Neuroscience Center/Laboratory Animal Center, Mustialankatu 1, FI-00014, University of Helsinki, Finland
| | - Jatta Huotari
- Institute of Biotechnology, HiLIFE Unit, Viikinkaari 5D, FI-00014, University of Helsinki, Finland
| | - Jaakko Kopra
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, Viikinkaari 5E, FI-00014, University of Helsinki, Finland
| | - Jaan-Olle Andressoo
- Institute of Biotechnology, HiLIFE Unit, Viikinkaari 5D, FI-00014, University of Helsinki, Finland
| | - Petteri T Piepponen
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, Viikinkaari 5E, FI-00014, University of Helsinki, Finland
| | - Mikko Airavaara
- Institute of Biotechnology, HiLIFE Unit, Viikinkaari 5D, FI-00014, University of Helsinki, Finland
| | - Anne Panhelainen
- Institute of Biotechnology, HiLIFE Unit, Viikinkaari 5D, FI-00014, University of Helsinki, Finland
| | - Michael D Gershon
- Department of Pathology & Cell Biology, Columbia University, NY, New York, USA
| | - Mart Saarma
- Institute of Biotechnology, HiLIFE Unit, Viikinkaari 5D, FI-00014, University of Helsinki, Finland
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6
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Albert K, Voutilainen MH, Domanskyi A, Piepponen TP, Ahola S, Tuominen RK, Richie C, Harvey BK, Airavaara M. Downregulation of tyrosine hydroxylase phenotype after AAV injection above substantia nigra: Caution in experimental models of Parkinson's disease. J Neurosci Res 2018; 97:346-361. [PMID: 30548446 DOI: 10.1002/jnr.24363] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 11/19/2018] [Accepted: 11/19/2018] [Indexed: 12/14/2022]
Abstract
Adeno-associated virus (AAV) vector-mediated delivery of human α-synuclein (α-syn) gene in rat substantia nigra (SN) results in increased expression of α-syn protein in the SN and striatum which can progressively degenerate dopaminergic neurons. Therefore, this model is thought to recapitulate the neurodegeneration in Parkinson's disease. Here, using AAV to deliver α-syn above the SN in male and female rats resulted in clear expression of human α-syn in the SN and striatum. The protein was associated with moderate behavioral deficits and some loss of tyrosine hydroxylase (TH) in the nigrostriatal areas. However, the immunohistochemistry results were highly variable and showed little to no correlation with behavior and the amount of α-syn present. Expression of green fluorescent protein (GFP) was used as a control to monitor gene delivery and expression efficacy. AAV-GFP resulted in a similar or greater TH loss compared to AAV-α-syn and therefore an additional vector that does not express a protein was tested. Vectors with double-floxed inverse open reading frame (DIO ORF) encoding fluorescent proteins that generate RNA that is not translated also resulted in TH downregulation in the SN but showed no significant behavioral deficits. These results demonstrate that although expression of wild-type human α-syn can cause neurodegeneration, the variability and lack of correlation with outcome measures are drawbacks with the model. Furthermore, design and control selection should be considered carefully because of conflicting conclusions due to AAV downregulation of TH, and we recommend caution with having highly regulated TH as the only marker for the dopamine system.
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Affiliation(s)
- Katrina Albert
- Institute of Biotechnology, Program of Developmental Biology, University of Helsinki, Helsinki, Finland
| | - Merja H Voutilainen
- Institute of Biotechnology, Program of Developmental Biology, University of Helsinki, Helsinki, Finland
| | - Andrii Domanskyi
- Institute of Biotechnology, Program of Developmental Biology, University of Helsinki, Helsinki, Finland
| | - T Petteri Piepponen
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland
| | - Sari Ahola
- Institute of Biotechnology, Program of Developmental Biology, University of Helsinki, Helsinki, Finland
| | - Raimo K Tuominen
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland
| | - Christopher Richie
- Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, Maryland
| | - Brandon K Harvey
- Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, Maryland
| | - Mikko Airavaara
- Institute of Biotechnology, Program of Developmental Biology, University of Helsinki, Helsinki, Finland
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7
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Renko JM, Bäck S, Voutilainen MH, Piepponen TP, Reenilä I, Saarma M, Tuominen RK. Mesencephalic Astrocyte-Derived Neurotrophic Factor (MANF) Elevates Stimulus-Evoked Release of Dopamine in Freely-Moving Rats. Mol Neurobiol 2018; 55:6755-6768. [PMID: 29349573 PMCID: PMC6061195 DOI: 10.1007/s12035-018-0872-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/07/2018] [Indexed: 01/12/2023]
Abstract
Neurotrophic factors (NTFs) hold potential as disease-modifying therapies for neurodegenerative disorders like Parkinson's disease. Glial cell line-derived neurotrophic factor (GDNF), cerebral dopamine neurotrophic factor (CDNF), and mesencephalic astrocyte-derived neurotrophic factor (MANF) have shown neuroprotective and restorative effects on nigral dopaminergic neurons in various animal models of Parkinson's disease. To date, however, their effects on brain neurochemistry have not been compared using in vivo microdialysis. We measured extracellular concentration of dopamine and activity of dopamine neurochemistry-regulating enzymes in the nigrostriatal system of rat brain. NTFs were unilaterally injected into the striatum of intact Wistar rats. Brain microdialysis experiments were performed 1 and 3 weeks later in freely-moving animals. One week after the treatment, we observed enhanced stimulus-evoked release of dopamine in the striatum of MANF-treated rats, but not in rats treated with GDNF or CDNF. MANF also increased dopamine turnover. Although GDNF did not affect the extracellular level of dopamine, we found significantly elevated tyrosine hydroxylase (TH) and catechol-O-methyltransferase (COMT) activity and decreased monoamine oxidase A (MAO-A) activity in striatal tissue samples 1 week after GDNF injection. The results show that GDNF, CDNF, and MANF have divergent effects on dopaminergic neurotransmission, as well as on dopamine synthetizing and metabolizing enzymes. Although the cellular mechanisms remain to be clarified, knowing the biological effects of exogenously administrated NTFs in intact brain is an important step towards developing novel neurotrophic treatments for degenerative brain diseases.
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Affiliation(s)
- Juho-Matti Renko
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, 00014, Helsinki, Finland.
| | - Susanne Bäck
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, 00014, Helsinki, Finland
| | - Merja H Voutilainen
- Institute of Biotechnology, Research Program in Developmental Biology, University of Helsinki, Viikinkaari 5D, P.O. Box 56, 00014, Helsinki, Finland
| | - T Petteri Piepponen
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, 00014, Helsinki, Finland
| | - Ilkka Reenilä
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, 00014, Helsinki, Finland
| | - Mart Saarma
- Institute of Biotechnology, Research Program in Developmental Biology, University of Helsinki, Viikinkaari 5D, P.O. Box 56, 00014, Helsinki, Finland
| | - Raimo K Tuominen
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, 00014, Helsinki, Finland
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Tammimäki A, Aonurm-Helm A, Männistö PT. Delayed O-methylation of l-DOPA in MB-COMT-deficient mice after oral administration of l-DOPA and carbidopa. Xenobiotica 2018; 48:325-331. [PMID: 28375049 DOI: 10.1080/00498254.2017.1315781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 04/02/2017] [Indexed: 06/07/2023]
Abstract
1. Catechol-O-methyltransferase (COMT) is involved in the O-methylation of l-DOPA, dopamine, and other catechols. The enzyme is expressed in two isoforms: soluble (S-COMT), which resides in the cytoplasm, and membrane-bound (MB-COMT), which is anchored to intracellular membranes. 2. To obtain specific information on the functions of COMT isoforms, we studied how a complete MB-COMT deficiency affects the total COMT activity in the body, peripheral l-DOPA levels, and metabolism after l-DOPA (10 mg kg-1) plus carbidopa (30 mg kg-1) administration by gastric tube in wild-type (WT) and MB-COMT-deficient mice. l-DOPA and 3-O-methyl-l-DOPA (3-OMD) levels were assayed in plasma, duodenum, and liver. 3. We showed that the selective lack of MB-COMT did not alter the total COMT activity, COMT enzyme kinetics, l-DOPA levels, or the total O-methylation of l-DOPA but delayed production of 3-OMD in plasma and peripheral tissues.
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Affiliation(s)
- Anne Tammimäki
- a Division of Pharmacology and Pharmacotherapy , Faculty of Pharmacy, University of Helsinki , Finland and
| | - Anu Aonurm-Helm
- b Division of Pharmacology and Toxicology , Institute of Biomedicine and Translational Medicine, Faculty of Medicine, University of Tartu , Tartu , Estonia
| | - Pekka T Männistö
- a Division of Pharmacology and Pharmacotherapy , Faculty of Pharmacy, University of Helsinki , Finland and
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Combination of CDNF and Deep Brain Stimulation Decreases Neurological Deficits in Late-stage Model Parkinson's Disease. Neuroscience 2018; 374:250-263. [PMID: 29408408 DOI: 10.1016/j.neuroscience.2018.01.052] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/22/2017] [Accepted: 01/25/2018] [Indexed: 12/17/2022]
Abstract
Several neurotrophic factors (NTF) are shown to be neuroprotective and neurorestorative in pre-clinical animal models for Parkinson's disease (PD), particularly in models where striatal dopamine neuron innervation partially exists. The results of clinical trials on late-stage patients have been modest. Subthalamic deep brain stimulation (STN DBS) is a proven treatment for a selected group of advanced PD patients. The cerebral dopamine neurotrophic factor (CDNF) is a promising therapeutic protein, but its effects in animal models of late-stage PD have remained under-researched. The interactions of NTF and STN DBS treatments have not been studied before. We found that a nigral CDNF protein alone had only a marginal effect on the behavioral deficits in a late-stage hemiparkinsonian rat model (6-OHDA MFB). However, CDNF improved the effect of acute STN DBS on front limb use asymmetry at 2 and 3 weeks after CDNF injection. STN lesion-modeling chronic stimulation-had an additive effect in reducing front limb use in the cylinder test and apomorphine-induced rotation. The combination of CDNF and acute STN DBS had a favorable effect on striatal tyrosine hydroxylase. This study presents a novel additive beneficial effect of NTF and STN DBS, which might be explained by the interaction of DBS-induced endogenous NTFs and exogenously injected CDNF. SNpc can be reached via similar trajectories used in clinical STN DBS, and this interaction is an important area for future studies.
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Svarcbahs R, Julku UH, Norrbacka S, Myöhänen TT. Removal of prolyl oligopeptidase reduces alpha-synuclein toxicity in cells and in vivo. Sci Rep 2018; 8:1552. [PMID: 29367610 PMCID: PMC5784134 DOI: 10.1038/s41598-018-19823-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/09/2018] [Indexed: 01/09/2023] Open
Abstract
Prolyl oligopeptidase (PREP) inhibition by small-molecule inhibitors can reduce alpha-synuclein (aSyn) aggregation, a key player in Parkinson's disease pathology. However, the significance of PREP protein for aSyn aggregation and toxicity is not known. We studied this in vivo by using PREP knock-out mice with viral vector injections of aSyn and PREP. Animal behavior was studied by locomotor activity and cylinder tests, microdialysis and HPLC were used to analyze dopamine levels, and different aSyn forms and loss of dopaminergic neurons were studied by immunostainings. Additionally, PREP knock-out cells were used to characterize the impact of PREP and aSyn on autophagy, proteasomal system and aSyn secretion. PREP knock-out animals were nonresponsive to aSyn-induced unilateral toxicity but combination of PREP and aSyn injections increased aSyn toxicity. Phosphorylated p129, proteinase K resistant aSyn levels and tyrosine hydroxylase positive cells were decreased in aSyn and PREP injected knock-out animals. These changes were accompanied by altered dopamine metabolite levels. PREP knock-out cells showed reduced response to aSyn, while cells were restored to wild-type cell levels after PREP overexpression. Taken together, our data suggests that PREP can enhance aSyn toxicity in vivo.
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Affiliation(s)
- Reinis Svarcbahs
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, 00014, Helsinki, Finland
| | - Ulrika H Julku
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, 00014, Helsinki, Finland
| | - Susanna Norrbacka
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, 00014, Helsinki, Finland
| | - Timo T Myöhänen
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, 00014, Helsinki, Finland.
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11
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Nigral injection of a proteasomal inhibitor, lactacystin, induces widespread glial cell activation and shows various phenotypes of Parkinson's disease in young and adult mouse. Exp Brain Res 2017; 235:2189-2202. [PMID: 28439627 DOI: 10.1007/s00221-017-4962-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 04/19/2017] [Indexed: 12/18/2022]
Abstract
Proteinaceous inclusions, called Lewy bodies, are used as a pathological hallmark for Parkinson's disease (PD). Lewy bodies contain insoluble α-synuclein (aSyn) and many other ubiquitinated proteins, suggesting a role for protein degradation system failure in the PD pathogenesis. Indeed, proteasomal dysfunction has been linked to PD but commonly used in vivo toxin models, such as 6-OHDA or MPTP, do not have a significant effect on the proteasomal system or protein aggregation. Therefore, we wanted to study the characteristics of a proteasomal inhibitor, lactacystin, as a PD model on young and adult mice. To study this, we performed stereotactic microinjection of lactacystin above the substantia nigra pars compacta in young (2 month old) and adult (12-14 month old) C57Bl/6 mice. Motor behavior was measured by locomotor activity and cylinder tests, and the markers of neuroinflammation, aSyn, and dopaminergic system were assessed by immunohistochemistry and HPLC. We found that lactacystin induced a Parkinson's disease-like motor phenotype 5-7 days after injection in young and adult mice, and this was associated with widespread neuroinflammation based on glial cell markers, aSyn accumulation in substantia nigra, striatal dopamine decrease, and loss of dopaminergic cell bodies in the substantia nigra and terminals in the striatum. When comparing young and adult mice, adult mice were more sensitive for dopaminergic degeneration after lactacystin injection that further supports the use of adult mice instead of young when modeling neurodegeneration. Our data showed that lactacystin is useful in modeling various aspects of Parkinson's disease, and taken together, our findings emphasize the role of a protein degradation deficit in Parkinson's disease pathology, and support the use of proteasomal inhibitors as Parkinson's disease models.
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12
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Prolyl Oligopeptidase Regulates Dopamine Transporter Phosphorylation in the Nigrostriatal Pathway of Mouse. Mol Neurobiol 2016; 55:470-482. [PMID: 27966077 DOI: 10.1007/s12035-016-0339-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 11/30/2016] [Indexed: 12/17/2022]
Abstract
Alpha-synuclein is the main component of Lewy bodies, a histopathological finding of Parkinson's disease. Prolyl oligopeptidase (PREP) is a serine protease that binds to α-synuclein and accelerates its aggregation in vitro. PREP enzyme inhibitors have been shown to block the α-synuclein aggregation process in vitro and in cellular models, and also to enhance the clearance of α-synuclein aggregates in transgenic mouse models. Moreover, PREP inhibitors have induced alterations in dopamine and metabolite levels, and dopamine transporter immunoreactivity in the nigrostriatal tissue. In this study, we characterized the role of PREP in the nigrostriatal dopaminergic and GABAergic systems of wild-type C57Bl/6 and PREP knockout mice, and the effects of PREP overexpression on these systems. Extracellular concentrations of dopamine and protein levels of phosphorylated dopamine transporter were increased and dopamine reuptake was decreased in the striatum of PREP knockout mice, suggesting increased internalization of dopamine transporter from the presynaptic membrane. Furthermore, PREP overexpression increased the level of dopamine transporters in the nigrostriatal tissue but decreased phosphorylated dopamine transporters in the striatum in wild-type mice. Our results suggest that PREP regulates the function of dopamine transporter, possibly by controlling the phosphorylation and transport of dopamine transporter into the striatum or synaptic membrane.
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Svarcbahs R, Julku UH, Myöhänen TT. Inhibition of Prolyl Oligopeptidase Restores Spontaneous Motor Behavior in the α-Synuclein Virus Vector-Based Parkinson's Disease Mouse Model by Decreasing α-Synuclein Oligomeric Species in Mouse Brain. J Neurosci 2016; 36:12485-12497. [PMID: 27927963 PMCID: PMC6601975 DOI: 10.1523/jneurosci.2309-16.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/19/2016] [Accepted: 10/21/2016] [Indexed: 02/07/2023] Open
Abstract
Decreased clearance of α-synuclein (aSyn) and aSyn protein misfolding and aggregation are seen as major factors in the pathogenesis of Parkinson's disease (PD) and other synucleinopathies that leads to disruption in neuronal function and eventually to cell death. Prolyl oligopeptidase (PREP) can accelerate the aSyn aggregation process, while inhibition of PREP by a small molecule inhibitor decreases aSyn oligomer formation and enhances its clearance via autophagy in different aSyn overexpressing cell types and in transgenic PD animal models. In this study, we investigated the impact of chronic PREP inhibition by a small molecule inhibitor, 4-phenylbutanoyl-l-prolyl-2(S)-cyanopyrrolidine (KYP-2047), on aSyn oligomerization, clearance, and underlying spontaneous motor behavior in a virus vector-based aSyn overexpression mouse model 4 weeks after aSyn microinjections and after the onset of symptomatic forepaw bias. Following 4 weeks of PREP inhibition, we saw an improved spontaneous forelimb use in mice that correlated with a decreased immunoreactivity against oligomer-specific forms of aSyn. Additionally, KYP-2047 had a trend to enhance dopaminergic systems activity. Our results suggest that PREP inhibition exhibits a beneficial effect on the aSyn clearance and aggregation in a virus mediated aSyn overexpression PD mouse model and that PREP inhibitors could be a novel therapeutic strategy for synucleinopathies. SIGNIFICANCE STATEMENT Alpha-synuclein (aSyn) has been implicated in Parkinson's disease, with aSyn aggregates believed to exert toxic effects on neurons, while prolyl oligopeptidase (PREP) has been shown to interact with aSyn both in cells and cell free conditions, thus enhancing its aggregation. We demonstrate the possibility to abolish motor imbalance caused by aSyn viral vector injection with chronic 4 week PREP inhibition by a potent small-molecule PREP inhibitor, 4-phenylbutanoyl-l-prolyl-2(S)-cyanopyrrolidine (KYP-2047). Treatment was initiated postsymptomatically, 4 weeks after aSyn injection. KYP-2047-treated animals had a significantly decreased amount of oligomeric aSyn particles and improved dopamine system activity compared to control animals. To our knowledge, this is the first time viral overexpression of aSyn has been countered and movement impairments abolished after their onset.
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Affiliation(s)
- Reinis Svarcbahs
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, FI-00014 Helsinki, Finland
| | - Ulrika H Julku
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, FI-00014 Helsinki, Finland
| | - Timo T Myöhänen
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, FI-00014 Helsinki, Finland
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14
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Peltola MA, Kuja-Panula J, Liuhanen J, Võikar V, Piepponen P, Hiekkalinna T, Taira T, Lauri SE, Suvisaari J, Kulesskaya N, Paunio T, Rauvala H. AMIGO-Kv2.1 Potassium Channel Complex Is Associated With Schizophrenia-Related Phenotypes. Schizophr Bull 2016; 42:191-201. [PMID: 26240432 PMCID: PMC4681558 DOI: 10.1093/schbul/sbv105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The enormous variability in electrical properties of neurons is largely affected by a multitude of potassium channel subunits. Kv2.1 is a widely expressed voltage-dependent potassium channel and an important regulator of neuronal excitability. The Kv2.1 auxiliary subunit AMIGO constitutes an integral part of the Kv2.1 channel complex in brain and regulates the activity of the channel. AMIGO and Kv2.1 localize to the distinct somatodendritic clusters at the neuronal plasma membrane. Here we have created and characterized a mouse line lacking the AMIGO gene. Absence of AMIGO clearly reduced the amount of the Kv2.1 channel protein in mouse brain and altered the electrophysiological properties of neurons. These changes were accompanied by behavioral and pharmacological abnormalities reminiscent of those identified in schizophrenia. Concomitantly, we have detected an association of a rare, population-specific polymorphism of KV2.1 (KCNB1) with human schizophrenia in a genetic isolate enriched with schizophrenia. Our study demonstrates the involvement of AMIGO-Kv2.1 channel complex in schizophrenia-related behavioral domains in mice and identifies KV2.1 (KCNB1) as a strong susceptibility gene for schizophrenia spectrum disorders in humans.
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Affiliation(s)
- Marjaana A. Peltola
- Neuroscience Center, University of Helsinki, Helsinki, Finland;,*To whom correspondence should be addressed; Neuroscience Center, PO Box 56 (Viikinkaari 4), FI-00014 University of Helsinki, Helsinki, Finland; tel: +358-2941-57649, fax: +358-2941-57620, e-mail:
| | | | - Johanna Liuhanen
- Public Health Genomics Unit, National Institute for Health and Welfare, Helsinki, Finland
| | - Vootele Võikar
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Petteri Piepponen
- Division of Pharmacology and Toxicology, University of Helsinki, Helsinki, Finland
| | - Tero Hiekkalinna
- Public Health Genomics Unit, National Institute for Health and Welfare, Helsinki, Finland;,Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Tomi Taira
- Neuroscience Center, University of Helsinki, Helsinki, Finland;,Department of Biosciences, University of Helsinki, Helsinki, Finland;,Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Sari E. Lauri
- Neuroscience Center, University of Helsinki, Helsinki, Finland;,Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Jaana Suvisaari
- Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki, Finland
| | | | - Tiina Paunio
- Public Health Genomics Unit, National Institute for Health and Welfare, Helsinki, Finland;,Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland;,Department of Psychiatry, Institute of Clinical Medicine, University of Helsinki, Helsinki, Finland
| | - Heikki Rauvala
- Neuroscience Center, University of Helsinki, Helsinki, Finland
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15
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Kumar A, Kopra J, Varendi K, Porokuokka LL, Panhelainen A, Kuure S, Marshall P, Karalija N, Härma MA, Vilenius C, Lilleväli K, Tekko T, Mijatovic J, Pulkkinen N, Jakobson M, Jakobson M, Ola R, Palm E, Lindahl M, Strömberg I, Võikar V, Piepponen TP, Saarma M, Andressoo JO. GDNF Overexpression from the Native Locus Reveals its Role in the Nigrostriatal Dopaminergic System Function. PLoS Genet 2015; 11:e1005710. [PMID: 26681446 PMCID: PMC4682981 DOI: 10.1371/journal.pgen.1005710] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Accepted: 11/06/2015] [Indexed: 12/14/2022] Open
Abstract
Degeneration of nigrostriatal dopaminergic system is the principal lesion in Parkinson’s disease. Because glial cell line-derived neurotrophic factor (GDNF) promotes survival of dopamine neurons in vitro and in vivo, intracranial delivery of GDNF has been attempted for Parkinson’s disease treatment but with variable success. For improving GDNF-based therapies, knowledge on physiological role of endogenous GDNF at the sites of its expression is important. However, due to limitations of existing genetic model systems, such knowledge is scarce. Here, we report that prevention of transcription of Gdnf 3’UTR in Gdnf endogenous locus yields GDNF hypermorphic mice with increased, but spatially unchanged GDNF expression, enabling analysis of postnatal GDNF function. We found that increased level of GDNF in the central nervous system increases the number of adult dopamine neurons in the substantia nigra pars compacta and the number of dopaminergic terminals in the dorsal striatum. At the functional level, GDNF levels increased striatal tissue dopamine levels and augmented striatal dopamine release and re-uptake. In a proteasome inhibitor lactacystin-induced model of Parkinson’s disease GDNF hypermorphic mice were protected from the reduction in striatal dopamine and failure of dopaminergic system function. Importantly, adverse phenotypic effects associated with spatially unregulated GDNF applications were not observed. Enhanced GDNF levels up-regulated striatal dopamine transporter activity by at least five fold resulting in enhanced susceptibility to 6-OHDA, a toxin transported into dopamine neurons by DAT. Further, we report how GDNF levels regulate kidney development and identify microRNAs miR-9, miR-96, miR-133, and miR-146a as negative regulators of GDNF expression via interaction with Gdnf 3’UTR in vitro. Our results reveal the role of GDNF in nigrostriatal dopamine system postnatal development and adult function, and highlight the importance of correct spatial expression of GDNF. Furthermore, our results suggest that 3’UTR targeting may constitute a useful tool in analyzing gene function. Intracranial delivery of GDNF has been attempted for Parkinson’s disease (PD) treatment but with variable success. For improving GDNF-based therapies, knowledge on physiological role of endogenous GDNF at the sites of its expression is important. However, due to limitations of existing genetic model systems, such knowledge is scarce. Here, we utilize an innovative genetic approach by targeting the 3’UTR regulation of Gdnf in mice. Such animals express elevated levels of Gdnf exclusively in natively Gdnf-expressing cells, enabling dissection of endogenous GDNF functions in vivo. We show that endogenous GDNF regulates dopamine system development and function and protects mice in a rodent PD model without side effects associated with ectopic GDNF applications. Further, we report how GDNF levels regulate kidney development and identify microRNAs which control GDNF expression. Our study highlights the importance of correct spatial expression of GDNF and opens a novel approach to study gene function in mice.
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Affiliation(s)
- Anmol Kumar
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Jaakko Kopra
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Kärt Varendi
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | | | - Anne Panhelainen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Satu Kuure
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Pepin Marshall
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nina Karalija
- Department of Histology and Cell Biology, Umeå University, Umeå, Sweden
| | - Mari-Anne Härma
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Carolina Vilenius
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Kersti Lilleväli
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Triin Tekko
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Jelena Mijatovic
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Nita Pulkkinen
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Madis Jakobson
- Department of Biochemistry and Developmental Biology, Institute of Biomedicine, University of Helsinki, Helsinki, Finland
| | - Maili Jakobson
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Roxana Ola
- Department of Biochemistry and Developmental Biology, Institute of Biomedicine, University of Helsinki, Helsinki, Finland
| | - Erik Palm
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Maria Lindahl
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Ingrid Strömberg
- Department of Histology and Cell Biology, Umeå University, Umeå, Sweden
| | - Vootele Võikar
- Neuroscience Center and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - T. Petteri Piepponen
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Mart Saarma
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Jaan-Olle Andressoo
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- * E-mail:
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16
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Kopra J, Vilenius C, Grealish S, Härma MA, Varendi K, Lindholm J, Castrén E, Võikar V, Björklund A, Piepponen TP, Saarma M, Andressoo JO. GDNF is not required for catecholaminergic neuron survival in vivo. Nat Neurosci 2015; 18:319-22. [PMID: 25710828 DOI: 10.1038/nn.3941] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jaakko Kopra
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Carolina Vilenius
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Shane Grealish
- Wallenberg Neuroscience Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Mari-Anne Härma
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Kärt Varendi
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Jesse Lindholm
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Eero Castrén
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Vootele Võikar
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Anders Björklund
- Wallenberg Neuroscience Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - T Petteri Piepponen
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Mart Saarma
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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17
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Li QQ, Sun CY, Luo YX, Xue YX, Meng SQ, Xu LZ, Chen N, Deng JH, Zhai HF, Kosten TR, Shi J, Lu L, Sun HQ. A conjugate vaccine attenuates morphine- and heroin-induced behavior in rats. Int J Neuropsychopharmacol 2015; 18:pyu093. [PMID: 25522425 PMCID: PMC4376548 DOI: 10.1093/ijnp/pyu093] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Currently approved medications for opioid addiction have shown clinical efficacy, but undesired side effects, dependence induced by the medications themselves, and low treatment compliance necessitate the need for novel therapies. METHODS A novel morphine-keyhole limpet hemocyanin conjugate vaccine was synthesized with 6-glutarylmorphine as the hapten and a lengthened linker of 6 carbon atoms. The titer and specificity of the triggered antibody were assessed by enzyme-linked immunosorbent assay. The effects of the vaccine on the morphine-induced elevation of dopamine levels in the nucleus accumbens were determined by high-performance liquid chromatography. The effects of the vaccine on morphine-induced locomotor sensitization and heroin-primed reinstatement of heroin self-administration were also assessed. RESULTS After subcutaneous administration in rats, the vaccine triggered a high antibody titer, with comparable specificity for morphine, 6-acetylmorphine, and heroin, but no interaction with dissimilar therapeutic opioid compounds, including buprenorphine, naloxone, and nalorphine, was observed. The vaccine significantly prevented the elevation of dopamine levels in the nucleus accumbens induced by a single morphine challenge. Moreover, the vaccine prevented the expression of morphine-induced locomotor sensitization and heroin-primed reinstatement of heroin seeking, suggesting its potential for preventing relapse. CONCLUSION These results demonstrate that active immunization with the present vaccine induces a robust morphine/heroin-specific antibody response in rats and attenuates the behavioral effects of morphine and heroin.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Lin Lu
- Peking University Sixth Hospital/Institute of Mental Health (Dr Li, Ms C.-Y. Sun, Dr Luo, Ms Meng, Mr Xu, Ms Deng, Drs Lu, and H.-Q. Sun), and National Institute on Drug Dependence, Peking University, Beijing, China (Drs Dr Li, Ms C.-Y. Sun, Dr Luo, Dr Xue, Ms Meng, Mr Xu, Ms Chen, Ms Deng, Drs Zhai, Shi, and Lu); Institute for Food and Drug Safety Evaluation, National Institutes for Food and Drug Control, Beijing, China (Dr Li); Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China (Drs Lu and H.-Q. Sun); Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas (Dr Kosten)
| | - Hong-Qiang Sun
- Peking University Sixth Hospital/Institute of Mental Health (Dr Li, Ms C.-Y. Sun, Dr Luo, Ms Meng, Mr Xu, Ms Deng, Drs Lu, and H.-Q. Sun), and National Institute on Drug Dependence, Peking University, Beijing, China (Drs Dr Li, Ms C.-Y. Sun, Dr Luo, Dr Xue, Ms Meng, Mr Xu, Ms Chen, Ms Deng, Drs Zhai, Shi, and Lu); Institute for Food and Drug Safety Evaluation, National Institutes for Food and Drug Control, Beijing, China (Dr Li); Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China (Drs Lu and H.-Q. Sun); Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas (Dr Kosten)
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18
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Galli S, Lopes DM, Ammari R, Kopra J, Millar SE, Gibb A, Salinas PC. Deficient Wnt signalling triggers striatal synaptic degeneration and impaired motor behaviour in adult mice. Nat Commun 2014; 5:4992. [PMID: 25318560 PMCID: PMC4218967 DOI: 10.1038/ncomms5992] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 08/15/2014] [Indexed: 12/31/2022] Open
Abstract
Synapse degeneration is an early and invariant feature of neurodegenerative diseases. Indeed, synapse loss occurs prior to neuronal degeneration and correlates with the symptom severity of these diseases. However, the molecular mechanisms that trigger synaptic loss remain poorly understood. Here we demonstrate that deficient Wnt signalling elicits synaptic degeneration in the adult striatum. Inducible expression of the secreted Wnt antagonist Dickkopf1 (Dkk1) in adult mice (iDkk1) decreases the number of cortico-striatal glutamatergic synapses and of D1 and D2 dopamine receptor clusters. Synapse loss occurs in the absence of axon retraction or cell death. The remaining excitatory terminals contain fewer synaptic vesicles and have a reduced probability of evoked transmitter release. IDkk1 mice show impaired motor coordination and are irresponsive to amphetamine. These studies identify Wnts as key endogenous regulators of synaptic maintenance and suggest that dysfunction in Wnt signalling contributes to synaptic degeneration at early stages in neurodegenerative diseases.
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Affiliation(s)
- Soledad Galli
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Douglas M. Lopes
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Rachida Ammari
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Jaakko Kopra
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki 00014, Finland
| | - Sarah E. Millar
- Department of Dermatology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Alasdair Gibb
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Patricia C. Salinas
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
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19
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Mice deficient in transmembrane prostatic acid phosphatase display increased GABAergic transmission and neurological alterations. PLoS One 2014; 9:e97851. [PMID: 24846136 PMCID: PMC4028278 DOI: 10.1371/journal.pone.0097851] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 04/25/2014] [Indexed: 02/06/2023] Open
Abstract
Prostatic acid phosphatase (PAP), the first diagnostic marker and present therapeutic target for prostate cancer, modulates nociception at the dorsal root ganglia (DRG), but its function in the central nervous system has remained unknown. We studied expression and function of TMPAP (the transmembrane isoform of PAP) in the brain by utilizing mice deficient in TMPAP (PAP−/− mice). Here we report that TMPAP is expressed in a subpopulation of cerebral GABAergic neurons, and mice deficient in TMPAP show multiple behavioral and neurochemical features linked to hyperdopaminergic dysregulation and altered GABAergic transmission. In addition to increased anxiety, disturbed prepulse inhibition, increased synthesis of striatal dopamine, and augmented response to amphetamine, PAP-deficient mice have enlarged lateral ventricles, reduced diazepam-induced loss of righting reflex, and increased GABAergic tone in the hippocampus. TMPAP in the mouse brain is localized presynaptically, and colocalized with SNARE-associated protein snapin, a protein involved in synaptic vesicle docking and fusion, and PAP-deficient mice display altered subcellular distribution of snapin. We have previously shown TMPAP to reside in prostatic exosomes and we propose that TMPAP is involved in the control of GABAergic tone in the brain also through exocytosis, and that PAP deficiency produces a distinct neurological phenotype.
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20
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Savolainen MH, Richie CT, Harvey BK, Männistö PT, Maguire-Zeiss KA, Myöhänen TT. The beneficial effect of a prolyl oligopeptidase inhibitor, KYP-2047, on alpha-synuclein clearance and autophagy in A30P transgenic mouse. Neurobiol Dis 2014; 68:1-15. [PMID: 24746855 DOI: 10.1016/j.nbd.2014.04.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 03/14/2014] [Accepted: 04/08/2014] [Indexed: 12/15/2022] Open
Abstract
The misfolding and aggregation of α-synuclein (aSyn) eventually lead to an accumulation of toxic forms that disturb normal neuronal function and result in cell death. aSyn rich inclusions are seen in Parkinson's disease, dementia with Lewy bodies and other synucleinopathies. Prolyl oligopeptidase (PREP) can accelerate the aggregation process of aSyn and the inhibition of PREP leads to a decreased amount of aggregated aSyn in cell models and in aSyn transgenic mice. In this study, we investigated the effect of 5- and 28-day PREP inhibitor (KYP-2047) treatments on a mouse strain carrying a point mutation in the aSyn coding gene. Following PREP inhibition, we found a decrease in high molecular-weight oligomeric aSyn and a concomitant increase in the amount of the autophagosome marker, LC3BII, suggesting enhanced macroautophagy (autophagy) and aSyn clearance by KYP-2047. Moreover, 28-day treatment with KYP-2047 caused significant increases in striatal dopamine levels. In cell culture, overexpression of PREP reduced the autophagy. Furthermore, the inhibition of PREP normalized the changes on autophagy markers (LC3BII and p62) caused by an autophagy inhibition or aSyn overexpression, and induced the expression of beclin 1, a positive regulator of autophagy. Taken together, our results suggest that PREP inhibition accelerates the clearance of protein aggregates via increased autophagy and thus normalizes the cell functions in vivo and in vitro. Therefore, PREP inhibition may have future potential in the treatment of synucleinopathies.
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Affiliation(s)
- Mari H Savolainen
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, 00014, Finland; Optogenetics and Transgenic Technology Core, National Institute of Drug Abuse, Baltimore, MD, USA
| | - Christopher T Richie
- Optogenetics and Transgenic Technology Core, National Institute of Drug Abuse, Baltimore, MD, USA
| | - Brandon K Harvey
- Optogenetics and Transgenic Technology Core, National Institute of Drug Abuse, Baltimore, MD, USA
| | - Pekka T Männistö
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, 00014, Finland
| | | | - Timo T Myöhänen
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, 00014, Finland; Department of Neuroscience, Georgetown University Medical Center, Washington DC, USA.
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21
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Characterization of the structural and functional determinants of MANF/CDNF in Drosophila in vivo model. PLoS One 2013; 8:e73928. [PMID: 24019940 PMCID: PMC3760817 DOI: 10.1371/journal.pone.0073928] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/24/2013] [Indexed: 11/28/2022] Open
Abstract
Mammalian MANF and CDNF proteins are evolutionarily conserved neurotrophic factors that can protect and repair mammalian dopaminergic neurons in vivo. In Drosophila, the sole MANF protein (DmManf) is needed for the maintenance of dopaminergic neurites and dopamine levels. Although both secreted and intracellular roles for MANF and CDNF have been demonstrated, very little is known about the molecular mechanism of their action. Here, by using a transgenic rescue approach in the DmManf mutant background we show that only full-length MANF containing both the amino-terminal saposin-like and carboxy-terminal SAP-domains can rescue the larval lethality of the DmManf mutant. Independent N- or C-terminal domains of MANF, even when co-expressed together, fail to rescue. Deleting the signal peptide or mutating the CXXC motif in the C-terminal domain destroys the activity of full-length DmManf. Positively charged surface amino acids and the C-terminal endoplasmic reticulum retention signal are necessary for rescue of DmManf mutant lethality when DmManf is expressed in a restricted pattern. Furthermore, rescue experiments with non-ubiquitous expression reveals functional differences between the C-terminal domain of human MANF and CDNF. Finally, DmManf and its C-terminal domain rescue mammalian sympathetic neurons from toxin-induced apoptosis in vitro demonstrating functional similarity of the mammalian and fly proteins. Our study offers further insights into the functional conservation between invertebrate and mammalian MANF/CDNF proteins and reveals the importance of the C-terminal domain for MANF activity in vivo.
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Hutchinson MR, Watkins LR. Why is neuroimmunopharmacology crucial for the future of addiction research? Neuropharmacology 2013; 76 Pt B:218-27. [PMID: 23764149 DOI: 10.1016/j.neuropharm.2013.05.039] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 05/13/2013] [Accepted: 05/23/2013] [Indexed: 12/13/2022]
Abstract
A major development in drug addiction research in recent years has been the discovery that immune signaling within the central nervous system contributes significantly to mesolimbic dopamine reward signaling induced by drugs of abuse, and hence is involved in the presentation of reward behaviors. Additionally, in the case of opioids, these hypotheses have advanced through to the discovery of the novel site of opioid action at the innate immune pattern recognition receptor Toll-like receptor 4 as the necessary triggering event that engages this reward facilitating central immune signaling. Thus, the hypothesis of major proinflammatory contributions to drug abuse was born. This review will examine these key discoveries, but also address several key lingering questions of how central immune signaling is able to contribute in this fashion to the pharmacodynamics of drugs of abuse. It is hoped that by combining the collective wisdom of neuroscience, immunology and pharmacology, into Neuroimmunopharmacology, we may more fully understanding the neuronal and immune complexities of how drugs of abuse, such as opioids, create their rewarding and addiction states. Such discoveries will point us in the direction such that one day soon we might successfully intervene to successfully treat drug addiction. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
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Affiliation(s)
- Mark R Hutchinson
- Discipline of Physiology, School of Medical Sciences, University of Adelaide, Level 5, Medical School South, Frome Rd, Adelaide, South Australia 5005, Australia.
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Catechol-O-methyltransferase (COMT) protein expression and activity after dopaminergic and noradrenergic lesions of the rat brain. PLoS One 2013; 8:e61392. [PMID: 23613844 PMCID: PMC3628796 DOI: 10.1371/journal.pone.0061392] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 03/08/2013] [Indexed: 11/19/2022] Open
Abstract
The occurrence of catechol-O-methyltransferase (COMT) in presynaptic neurons remains controversial. This study utilized dopaminergic and noradrenergic toxins to assess the presence of COMT in the presynaptic neurons originating from the substantia nigra, ventral tegmental area or locus coeruleus. Destruction of dopaminergic and noradrenergic neurons was assessed by measuring the dopamine and noradrenaline content in the projection areas of these neurons. Additionally, COMT protein expression and activity were examined in several projection areas to determine whether there are any changes in COMT values. Colocalization studies were done to identify COMT-containing postsynaptic neurons. Despite successful lesioning of dopaminergic and noradrenergic neurons, no changes in COMT protein expression or activity could be noted. These results strongly suggest that COMT is not present in presynaptic dopaminergic and noradrenergic neurons. There was a high colocalization of COMT with the GABAergic marker of short neurons both in the striatum and cortex but only a weak, if any, with the cholinergic marker in the cortex.
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Piltonen M, Savolainen M, Patrikainen S, Baekelandt V, Myöhänen TT, Männistö PT. Comparison of motor performance, brain biochemistry and histology of two A30P α-synuclein transgenic mouse strains. Neuroscience 2012; 231:157-68. [PMID: 23219665 DOI: 10.1016/j.neuroscience.2012.11.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 11/21/2012] [Accepted: 11/24/2012] [Indexed: 10/27/2022]
Abstract
Three point mutations in the SNCA gene encoding α-synuclein (aSyn) have been associated with autosomal dominant forms of Parkinson's disease. To better understand the role of the A30P mutant aSyn, we compared two transgenic mouse strains: a knock-in mouse with an introduced A30P point mutation in the wild-type (WT) gene (Snca(tm(A30P))) and a transgenic (Tg) mouse overexpressing the human A30P aSyn gene under the prion promoter [tg(Prnp-SNCA A30P)]. The brain aSyn load, motor performance, brain dopamine (DA) and sensitivity to 6-hydroxydopamine (6-OHDA) were studied in these mice. aSyn was evidently accumulating with age in all mice, particularly in tg(Prnp-SNCA A30P) Tg mice. There were no robust changes in basal locomotor activities of the mice of either line at 6 months, but after 1 year, tg(Prnp-SNCA A30P) Tg mice developed severe problems with vertical movements. However, the younger Tg mice had a reduced locomotor response to 1mg/kg of d-amphetamine. Snca(tm(A30P)) mice with the targeted mutation (Tm) were slightly hyperactive at all ages. Less 6-OHDA was required in tg(Prnp-SNCA A30P) Tg (1 μg) than in WT (3μg) mice for an ipsilateral rotational bias by d-amphetamine. That was not seen with the Snca(tm(A30P)) strain. A small dose of 6-OHDA (0.33 μg) led to contralateral rotations and elevated striatal DA in Tg/Tm mice of both lines but otherwise 6-OHDA-induced striatal DA depletion was similar in all mice, indicating no A30P-aSyn-related toxin sensitivity. 3,4-Dihydroxyphenylacetic acid/DA-ratio was elevated in tg(Prnp-SNCA A30P) mice, suggesting an enhanced DA turnover. This ratio and homovanillic acid/DA-ratio were declined in Snca(tm(A30P)) mice. Our results demonstrate that the two differently constructed A30P-aSyn mouse strains have distinct behavioral and biochemical characteristics, some of which are opposite. Since the two lines with the same background were not identically produced, the deviations found may be partially caused by factors other than aSyn-related genetic differences.
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Affiliation(s)
- M Piltonen
- Division of Pharmacology and Toxicology, Faculty of Pharmacy, P.O. Box 56, FIN-00014 University of Helsinki, Viikinkaari 5E, 00790 Helsinki, Finland.
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Song Z, Guo Q, Zhang J, Li M, Liu C, Zou W. Proteomic analysis of PKCγ-related proteins in the spinal cord of morphine-tolerant rats. PLoS One 2012; 7:e42068. [PMID: 22860055 PMCID: PMC3409149 DOI: 10.1371/journal.pone.0042068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 07/02/2012] [Indexed: 12/16/2022] Open
Abstract
Background Morphine tolerance is a common drawback of chronic morphine exposure, hindering use of this drug. Studies have shown that PKCã may play a key role in the development of morphine tolerance, although the mechanisms are not fully known. Methodology/Principal Findings In a rat model of morphine tolerance, PKCã knockdown in the spinal cord was successfully carried out using RNA interference (RNAi) with lentiviral vector-mediated short hairpin RNA of PKCã (LV-shPKCã). Spinal cords (L4-L5) were obtained surgically from morphine-tolerant (MT) rats with and without PKCã knockdown, for comparative proteomic analysis. Total proteins from the spinal cords (L4-L5) were extracted and separated using two-dimensional gel electrophoresis (2DGE); 2D gel images were analyzed with PDQuest software. Seven differential gel-spots were observed with increased spot volume, and 18 spots observed with decreased spot volume. Among these, 13 differentially expressed proteins (DEPs) were identified with matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), comparing between MT rats with and without PKCã knockdown. The DEPs identified have roles in the cytoskeleton, as neurotrophic factors, in oxidative stress, in ion metabolism, in cell signaling, and as chaperones. Three DEPs (GFAP, FSCN and GDNF) were validated with Western blot analysis, confirming the DEP data. Furthermore, using immunohistochemical analysis, we reveal for the first time that FSCN is involved in the development of morphine tolerance. Conclusions/Significance These data cast light on the proteins associated with the PKCã activity during morphine tolerance, and hence may contribute to clarification of the mechanisms by which PKCã influences MT.
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Affiliation(s)
- Zongbin Song
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, China
| | - Qulian Guo
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, China
| | - Jie Zhang
- Department of Anesthesiology, the Maternal and Child Health Hospital of Hunan Province, Changsha, China
| | - Maoyu Li
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha, China
| | - Chang Liu
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, China
| | - Wangyuan Zou
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, China
- * E-mail:
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Different Interactions of Prolyl Oligopeptidase and Neurotensin in Dopaminergic Function of the Rat Nigrostriatal and Mesolimbic Pathways. Neurochem Res 2012; 37:2033-41. [DOI: 10.1007/s11064-012-0825-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 06/05/2012] [Accepted: 06/08/2012] [Indexed: 10/28/2022]
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Mudò G, Mäkelä J, Liberto VD, Tselykh TV, Olivieri M, Piepponen P, Eriksson O, Mälkiä A, Bonomo A, Kairisalo M, Aguirre JA, Korhonen L, Belluardo N, Lindholm D. Transgenic expression and activation of PGC-1α protect dopaminergic neurons in the MPTP mouse model of Parkinson's disease. Cell Mol Life Sci 2012; 69:1153-65. [PMID: 21984601 PMCID: PMC11114858 DOI: 10.1007/s00018-011-0850-z] [Citation(s) in RCA: 203] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 08/31/2011] [Accepted: 09/22/2011] [Indexed: 10/17/2022]
Abstract
Mitochondrial dysfunction and oxidative stress occur in Parkinson's disease (PD), but little is known about the molecular mechanisms controlling these events. Peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) is a transcriptional coactivator that is a master regulator of oxidative stress and mitochondrial metabolism. We show here that transgenic mice overexpressing PGC-1α in dopaminergic neurons are resistant against cell degeneration induced by the neurotoxin MPTP. The increase in neuronal viability was accompanied by elevated levels of mitochondrial antioxidants SOD2 and Trx2 in the substantia nigra of transgenic mice. PGC-1α overexpression also protected against MPTP-induced striatal loss of dopamine, and mitochondria from PGC-1α transgenic mice showed an increased respiratory control ratio compared with wild-type animals. To modulate PGC-1α, we employed the small molecular compound, resveratrol (RSV) that protected dopaminergic neurons against the MPTP-induced cell degeneration almost to the same extent as after PGC-1α overexpression. As studied in vitro, RSV activated PGC-1α in dopaminergic SN4741 cells via the deacetylase SIRT1, and enhanced PGC-1α gene transcription with increases in SOD2 and Trx2. Taken together, the results reveal an important function of PGC-1α in dopaminergic neurons to combat oxidative stress and increase neuronal viability. RSV and other compounds acting via SIRT1/PGC-1α may prove useful as neuroprotective agents in PD and possibly in other neurological disorders.
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Affiliation(s)
- Giuseppa Mudò
- Department of Experimental Biomedicine and Clinical Neuroscience, Division of Human Physiology, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy
| | - Johanna Mäkelä
- Institute of Biomedicine, Biochemistry and Developmental Biology, University of Helsinki, 00014 Helsinki, Finland
| | - Valentina Di Liberto
- Department of Experimental Biomedicine and Clinical Neuroscience, Division of Human Physiology, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy
| | - Timofey V. Tselykh
- Institute of Biomedicine, Biochemistry and Developmental Biology, University of Helsinki, 00014 Helsinki, Finland
- Minerva Medical Research Institute, Biomedicum-2 Helsinki, Tukholmankatu 8, 00290 Helsinki, Finland
| | - Melania Olivieri
- Department of Experimental Biomedicine and Clinical Neuroscience, Division of Human Physiology, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy
| | - Petteri Piepponen
- Faculty of Pharmacy, Division of Pharmacology and Toxicology, University of Helsinki, 00014 Helsinki, Finland
| | - Ove Eriksson
- Institute of Biomedicine, Biochemistry and Developmental Biology, University of Helsinki, 00014 Helsinki, Finland
- Research Program Unit, Biomedicum Helsinki, University of Helsinki, 00014 Helsinki, Finland
| | - Annika Mälkiä
- Minerva Medical Research Institute, Biomedicum-2 Helsinki, Tukholmankatu 8, 00290 Helsinki, Finland
| | - Alessandra Bonomo
- Department of Experimental Biomedicine and Clinical Neuroscience, Division of Human Physiology, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy
| | - Minna Kairisalo
- Minerva Medical Research Institute, Biomedicum-2 Helsinki, Tukholmankatu 8, 00290 Helsinki, Finland
| | - Jose A. Aguirre
- Department of Human Physiology, School of Medicine, University of Malaga, 27071 Malaga, Spain
| | - Laura Korhonen
- Institute of Biomedicine, Biochemistry and Developmental Biology, University of Helsinki, 00014 Helsinki, Finland
- Minerva Medical Research Institute, Biomedicum-2 Helsinki, Tukholmankatu 8, 00290 Helsinki, Finland
| | - Natale Belluardo
- Department of Experimental Biomedicine and Clinical Neuroscience, Division of Human Physiology, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy
| | - Dan Lindholm
- Institute of Biomedicine, Biochemistry and Developmental Biology, University of Helsinki, 00014 Helsinki, Finland
- Minerva Medical Research Institute, Biomedicum-2 Helsinki, Tukholmankatu 8, 00290 Helsinki, Finland
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Coller JK, Hutchinson MR. Implications of central immune signaling caused by drugs of abuse: mechanisms, mediators and new therapeutic approaches for prediction and treatment of drug dependence. Pharmacol Ther 2012; 134:219-45. [PMID: 22316499 DOI: 10.1016/j.pharmthera.2012.01.008] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 01/12/2023]
Abstract
In the past two decades a trickle of manuscripts examining the non-neuronal central nervous system immune consequences of the drugs of abuse has now swollen to a significant body of work. Initially, these studies reported associative evidence of central nervous system proinflammation resulting from exposure to the drugs of abuse demonstrating key implications for neurotoxicity and disease progression associated with, for example, HIV infection. However, more recently this drug-induced activation of central immune signaling is now understood to contribute substantially to the pharmacodynamic actions of the drugs of abuse, by enhancing the engagement of classical mesolimbic dopamine reward pathways and withdrawal centers. This review will highlight the key in vivo animal, human, biological and molecular evidence of these central immune signaling actions of opioids, alcohol, cocaine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA). Excitingly, this new appreciation of central immune signaling activity of drugs of abuse provides novel therapeutic interventions and opportunities to identify 'at risk' individuals through the use of immunogenetics. Discussion will also cover the evidence of modulation of this signaling by existing clinical and pre-clinical drug candidates, and novel pharmacological targets. Finally, following examination of the breadth of central immune signaling actions of the drugs of abuse highlighted here, the current known common immune signaling components will be outlined and their impact on established addiction neurocircuitry discussed, thereby synthesizing a common neuroimmune hypothesis of addiction.
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Affiliation(s)
- Janet K Coller
- Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, South Australia 5005, Australia.
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Lahti L, Peltopuro P, Piepponen TP, Partanen J. Cell-autonomous FGF signaling regulates anteroposterior patterning and neuronal differentiation in the mesodiencephalic dopaminergic progenitor domain. Development 2012; 139:894-905. [PMID: 22278924 DOI: 10.1242/dev.071936] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The structure and projection patterns of adult mesodiencephalic dopaminergic (DA) neurons are one of the best characterized systems in the vertebrate brain. However, the early organization and development of these nuclei remain poorly understood. The induction of midbrain DA neurons requires sonic hedgehog (Shh) from the floor plate and fibroblast growth factor 8 (FGF8) from the isthmic organizer, but the way in which FGF8 regulates DA neuron development is unclear. We show that, during early embryogenesis, mesodiencephalic neurons consist of two distinct populations: a diencephalic domain, which is probably independent of isthmic FGFs; and a midbrain domain, which is dependent on FGFs. Within these domains, DA progenitors and precursors use partly different genetic programs. Furthermore, the diencephalic DA domain forms a distinct cell population, which also contains non-DA Pou4f1(+) cells. FGF signaling operates in proliferative midbrain DA progenitors, but is absent in postmitotic DA precursors. The loss of FGFR1/2-mediated signaling results in a maturation failure of the midbrain DA neurons and altered patterning of the midbrain floor. In FGFR mutants, the DA domain adopts characteristics that are typical for embryonic diencephalon, including the presence of Pou4f1(+) cells among TH(+) cells, and downregulation of genes typical of midbrain DA precursors. Finally, analyses of chimeric embryos indicate that FGF signaling regulates the development of the ventral midbrain cell autonomously.
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Affiliation(s)
- Laura Lahti
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
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30
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Impaired striatal dopamine output of homozygous Wfs1 mutant mice in response to [K+] challenge. J Physiol Biochem 2010; 67:53-60. [DOI: 10.1007/s13105-010-0048-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 09/21/2010] [Indexed: 12/18/2022]
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Käenmäki M, Tammimäki A, Garcia-Horsman JA, Myöhänen T, Schendzielorz N, Karayiorgou M, Gogos JA, Männistö PT. Importance of membrane-bound catechol-O-methyltransferase in L-DOPA metabolism: a pharmacokinetic study in two types of Comt gene modified mice. Br J Pharmacol 2010; 158:1884-94. [PMID: 19930170 DOI: 10.1111/j.1476-5381.2009.00494.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND AND PURPOSE Catechol-O-methyltransferase (COMT) metabolizes compounds containing catechol structures and has two forms: soluble (S-COMT) and membrane-bound (MB-COMT). Here we report the generation of a mouse line that expresses MB-COMT but not S-COMT. We compared the effects of deleting S-COMT only or both COMT forms on the pharmacokinetics of oral L-DOPA. EXPERIMENTAL APPROACH L-DOPA (10 mg kg(-1)) and carbidopa (30 mg kg(-1)) were given to mice by gastric tube, and samples were taken at various times. HPLC was used to measure L-DOPA in plasma and tissue samples, and dopamine and its metabolites in brain. Immunohistochemistry and Western blotting were used to characterize the distribution of COMT protein isoforms. KEY RESULTS Lack of S-COMT did not affect the levels of L-DOPA in plasma or peripheral tissues, whereas in the full COMT-knock-out mice, these levels were increased. The levels of 3-O-methyldopa were significantly decreased in the S-COMT-deficient mice. In the brain, L-DOPA levels were not significantly increased, and dopamine was increased only in females. The total COMT activity in the S-COMT-deficient mice was 22-47% of that in the wild-type mice. In peripheral tissues, female mice had lower COMT activity than the males. CONCLUSIONS AND IMPLICATIONS In S-COMT-deficient mice, MB-COMT in the liver and the duodenum is able to O-methylate about one-half of exogenous L-DOPA. Sexual dimorphism and activity of the two COMT isoforms seems to be tissue specific and more prominent in peripheral tissues than in the brain.
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Affiliation(s)
- M Käenmäki
- Division of Pharmacology and Toxicology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland.
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Mijatovic J, Piltonen M, Alberton P, Männistö PT, Saarma M, Piepponen TP. Constitutive Ret signaling is protective for dopaminergic cell bodies but not for axonal terminals. Neurobiol Aging 2009; 32:1486-94. [PMID: 19767128 DOI: 10.1016/j.neurobiolaging.2009.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 08/03/2009] [Accepted: 08/22/2009] [Indexed: 12/27/2022]
Abstract
Ret is the canonical signaling receptor for glial cell line-derived neurotrophic factor (GDNF), which has been shown to have neuroprotective effects when administered prior to neurotoxic challenge. A missense Meth918Thr mutation causes the constitutive activation of Ret, resulting in multiple endocrine neoplasia type 2 B (MEN2B). To clarify the role of Ret signaling in neuroprotection, we studied the effects of the neurotoxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 6-hydroxydopamine (6-OHDA) on the dopaminergic system of mice carrying the MEN2B mutation. We found that MEN2B mice were significantly more resistant to nigral tyrosine hydroxylase (TH)-positive cell loss induced by unilateral striatal 6-OHDA than Wt mice. However, 6-OHDA caused profound dopamine (DA) depletion in the striatum of both MEN2B and Wt mice. Systemic MPTP caused similar DA depletion and a decrease in TH-immunostaining in the striatum of MEN2B and Wt mice. Neither neurotoxin induced a compensatory increase in striatal metabolite/DA ratios in the MEN2B mice, possibly contributing to an increased amphetamine-induced turning behavior observed in behavioral assessments of these mice. Thus, our data suggest that activated Ret protects DA cell bodies in the substantia nigra pars compacta, but does not protect DA axons in the striatum.
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Affiliation(s)
- Jelena Mijatovic
- Division of Pharmacology and Toxicology, Faculty of Pharmacy, University of Helsinki, Finland.
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Carnicella S, Ahmadiantehrani S, Janak PH, Ron D. GDNF is an endogenous negative regulator of ethanol-mediated reward and of ethanol consumption after a period of abstinence. Alcohol Clin Exp Res 2009; 33:1012-24. [PMID: 19302086 DOI: 10.1111/j.1530-0277.2009.00922.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND We previously found that activation of the glial cell line-derived neurotrophic factor (GDNF) pathway in the ventral tegmental area (VTA) reduces ethanol-drinking behaviors. In this study, we set out to assess the contribution of endogenous GDNF or its receptor GFRalpha1 to the regulation of ethanol-related behaviors. METHODS GDNF and GFRalpha1 heterozygote mice (HET) and their wild-type littermate controls (WT) were used for the studies. Ethanol-induced hyperlocomotion, sensitization, and conditioned place preference (CPP), as well as ethanol consumption before and after a period of abstinence were evaluated. Blood ethanol concentration (BEC) was also measured. RESULTS We observed no differences between the GDNF HET and WT mice in the level of locomotor activity or in sensitization to ethanol-induced hyperlocomotion after systemic injection of a nonhypnotic dose of ethanol and in BEC. However, GDNF and GFRalpha1 mice exhibited increased place preference to ethanol as compared with their WT littermates. The levels of voluntary ethanol or quinine consumption were similar in the GDNF HET and WT mice, however, a small but significant increase in saccharin intake was observed in the GDNF HET mice. No changes were detected in voluntary ethanol, saccharin or quinine consumption of GFRalpha1 HET mice as compared with their WT littermates. Interestingly, however, both the GDNF and GFRalpha1 HET mice consumed much larger quantities of ethanol after a period of abstinence from ethanol as compared with their WT littermates. Furthermore, the increase in ethanol consumption after abstinence was found to be specific for ethanol as similar levels of saccharin intake were measured in the GDNF and GFRalpha1 HET and WT mice after abstinence. CONCLUSIONS Our results suggest that endogenous GDNF negatively regulates the rewarding effect of ethanol and ethanol-drinking behaviors after a period of abstinence.
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Affiliation(s)
- Sebastien Carnicella
- The Ernest Gallo Research Center, University of California-San Francisco, Emeryville, CA 94608, USA
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L-Dopa-induced desensitization depends on 5-hydroxytryptamine imbalance in hemiparkinsonian rats. Neuroreport 2009; 20:313-8. [DOI: 10.1097/wnr.0b013e328321e704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Evidence that DmMANF is an invertebrate neurotrophic factor supporting dopaminergic neurons. Proc Natl Acad Sci U S A 2009; 106:2429-34. [PMID: 19164766 DOI: 10.1073/pnas.0810996106] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In vertebrates the development and function of the nervous system is regulated by neurotrophic factors (NTFs). Despite extensive searches no neurotrophic factors have been found in invertebrates. However, cell ablation studies in Drosophila suggest trophic interaction between neurons and glia. Here we report the invertebrate neurotrophic factor in Drosophila, DmMANF, homologous to mammalian MANF and CDNF. DmMANF is expressed in glia and essential for maintenance of dopamine positive neurites and dopamine levels. The abolishment of both maternal and zygotic DmMANF leads to the degeneration of axonal bundles in the embryonic central nervous system and subsequent nonapoptotic cell death. The rescue experiments confirm DmMANF as a functional ortholog of the human MANF gene thus opening the window for comparative studies of this protein family with potential for the treatment of Parkinson's disease.
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Abstract
The glial cell line-derived neurotrophic factor (GDNF) is a secreted protein, best known for its role in the development of the central and peripheral nervous systems and the survival of adult dopaminergic neurons. More recently, accumulating evidence suggests that GDNF plays a unique role in negatively regulating the actions of drugs of abuse. In this article, we review these data and highlight the possibility that the GDNF pathway may be a promising target for the treatment of addiction.
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Vihavainen T, Relander TRA, Leiviskä R, Airavaara M, Tuominen RK, Ahtee L, Piepponen TP. Chronic nicotine modifies the effects of morphine on extracellular striatal dopamine and ventral tegmental GABA. J Neurochem 2008; 107:844-54. [PMID: 18786163 DOI: 10.1111/j.1471-4159.2008.05676.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Previously, we have shown that 7-week oral nicotine treatment enhances morphine-induced behaviors and dopaminergic activity in the mouse brain. In this study, we further characterized the nicotine-morphine interaction in the mesolimbic and nigrostriatal dopaminergic systems, as well as in the GABAergic control of these systems. In nicotine-pretreated mice, morphine-induced dopamine release in the caudate putamen and nucleus accumbens was significantly augmented, as measured by microdialysis. Chronic nicotine treatment did not change basal extracellular concentrations of dopamine and its metabolites in the caudate putamen and nucleus accumbens, nor did it affect the rate of dopamine synthesis, as assessed by 3-hydroxybenzylhydrazine dihydrochloride-induced DOPA accumulation. GABAergic control of dopaminergic activity was studied by measuring extracellular GABA in the presence of nipecotic acid, an inhibitor of GABA uptake. Acute (0.3 mg/kg or 0.5 mg/kg i.p.) and chronic nicotine, as well as morphine (15 mg/kg s.c.) in control mice decreased nipecotic acid-induced increase in extracellular GABA in the ventral tegmental area/substantia nigra (VTA/SN). In contrast, in nicotine-treated mice, morphine increased GABA levels in the presence of nipecotic acid. We did not find any alterations in GABA(B)-receptor function after chronic nicotine treatment. Thus, our data show that chronic nicotine treatment sensitizes dopaminergic systems to morphine and affects GABAergic systems in the VTA/SN.
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Affiliation(s)
- Tanja Vihavainen
- Division of Pharmacology and Toxicology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland.
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Mijatovic J, Patrikainen O, Yavich L, Airavaara M, Ahtee L, Saarma M, Petteri Piepponen T. Characterization of the striatal dopaminergic neurotransmission in MEN2B mice with elevated cerebral tissue dopamine. J Neurochem 2008; 105:1716-25. [DOI: 10.1111/j.1471-4159.2008.05265.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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40
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Lack of robust protective effect of quercetin in two types of 6-hydroxydopamine-induced parkinsonian models in rats and dopaminergic cell cultures. Brain Res 2008; 1203:149-59. [PMID: 18329008 DOI: 10.1016/j.brainres.2008.01.089] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Revised: 01/29/2008] [Accepted: 01/31/2008] [Indexed: 11/21/2022]
Abstract
In the present study, we examined the ability of a flavonoid quercetin to prevent 6-hydroxydopamine (6-OHDA)-induced oxygen radical formation and cytotoxicity in vitro and neurotoxicity in vivo. Quercetin (10-100 microM) had an acute significant antioxidant effect against the 6-OHDA-induced (30 microM) oxygen radical formation in catecholaminergic SH-SY5Y neuroblastoma cells. Moreover, in these cells, quercetin at 10-50 microM had a significant protective effect against 6-OHDA though at 100 microM it was itself harmful to the cells. The possible effect of quercetin in preventing neurotoxicity in unilateral medial forebrain bundle (full nigral lesion) or striatal (partial lesion) 6-OHDA rat lesion models of Parkinson's disease was studied in three treatment schedules: a 7-day pre- or post-treatment or their combination. Rotational responses to apomorphine (0.1 mg/kg, subcutaneously) and d-amphetamine (2.5 mg/kg, intraperitoneally) were assessed at weeks 1 and 2 post-lesion. Quercetin had no consistent neuroprotective effect in either model at 50-200 mg/kg once a day or 100 mg/kg twice a day. Furthermore, no protection was observed in tyrosine hydroxylase positive nigral cell numbers, striatal fiber density or in striatal levels of dopamine. These in vitro and in vivo results cast doubt on the theory that quercetin exerts reliable neuroprotective effects against 6-OHDA-induced toxicity. In vitro, quercetin seems to be protective at low doses but damaging at high doses.
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Abstract
This paper is the 29th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning 30 years of research. It summarizes papers published during 2006 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurological disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367, United States.
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Rantamäki T, Hendolin P, Kankaanpää A, Mijatovic J, Piepponen P, Domenici E, Chao MV, Männistö PT, Castrén E. Pharmacologically diverse antidepressants rapidly activate brain-derived neurotrophic factor receptor TrkB and induce phospholipase-Cgamma signaling pathways in mouse brain. Neuropsychopharmacology 2007; 32:2152-62. [PMID: 17314919 DOI: 10.1038/sj.npp.1301345] [Citation(s) in RCA: 240] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Previous studies suggest that brain-derived neurotrophic factor and its receptor TrkB are critically involved in the therapeutic actions of antidepressant drugs. We have previously shown that the antidepressants imipramine and fluoxetine produce a rapid autophosphorylation of TrkB in the rodent brain. In the present study, we have further examined the biochemical and functional characteristics of antidepressant-induced TrkB activation in vivo. We show that all the antidepressants examined, including inhibitors of monoamine transporters and metabolism, activate TrkB rapidly in the rodent anterior cingulate cortex and hippocampus. Furthermore, the results indicate that acute and long-term antidepressant treatments induce TrkB-mediated activation of phospholipase-Cgamma1 (PLCgamma1) and increase the phosphorylation of cAMP-related element binding protein, a major transcription factor mediating neuronal plasticity. In contrast, we have not observed any modulation of the phosphorylation of TrkB Shc binding site, phosphorylation of mitogen-activated protein kinase or AKT by antidepressants. We also show that in the forced swim test, the behavioral effects of specific serotonergic antidepressant citalopram, but not those of the specific noradrenergic antidepressant reboxetine, are crucially dependent on TrkB signaling. Finally, brain monoamines seem to be critical mediators of antidepressant-induced TrkB activation, as antidepressants reboxetine and citalopram do not produce TrkB activation in the brains of serotonin- or norepinephrine-depleted mice. In conclusion, our data suggest that rapid activation of the TrkB neurotrophin receptor and PLCgamma1 signaling is a common mechanism for all antidepressant drugs.
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Affiliation(s)
- Tomi Rantamäki
- Neuroscience Center, University of Helsinki, PO box 56, 00014 Helsinki, Finland
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Mijatovic J, Airavaara M, Planken A, Auvinen P, Raasmaja A, Piepponen TP, Costantini F, Ahtee L, Saarma M. Constitutive Ret activity in knock-in multiple endocrine neoplasia type B mice induces profound elevation of brain dopamine concentration via enhanced synthesis and increases the number of TH-positive cells in the substantia nigra. J Neurosci 2007; 27:4799-809. [PMID: 17475787 PMCID: PMC6672089 DOI: 10.1523/jneurosci.5647-06.2007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ret is the common signaling receptor for glial cell line-derived neurotrophic factor (GDNF) and other ligands of the GDNF family that have potent effects on brain dopaminergic neurons. The Met918Thr mutation leads to constitutive activity of Ret receptor tyrosine kinase, causing the cancer syndrome called multiple endocrine neoplasia type B (MEN2B). We used knock-in MEN2B mice with the Ret-MEN2B mutation to study the effects of constitutive Ret activity on the brain dopaminergic system and found robustly increased concentrations of dopamine (DA) and its metabolites in the striatum, cortex, and hypothalamus. The concentrations of brain serotonin were not affected and those of noradrenaline were slightly increased only in the lower brainstem. Tyrosine hydroxylase (TH) protein levels were increased in the striatum and substantia nigra/ventral tegmental area (SN/VTA), and TH mRNA levels were increased in SN/VTA of MEN2B mice, suggesting that constitutive Ret activity increases DA levels by increasing its synthesis. Also, the striatal DA transporter protein levels in the MEN2B mice were increased, which agrees with increased sensitivity of these mice to the stimulatory effects of cocaine. In the SN pars compacta of homozygous MEN2B mice, we found a 26% increase in the number of TH-positive cells, but no differences were found in the VTA. Thus, we show here that the constitutive Ret activity in mice is sufficient to increase the number of dopaminergic neurons and leads to profound elevation of brain DA concentration. These data clearly suggest that Ret activity per se can have a direct biological function that actively changes and shapes the brain dopaminergic system.
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Affiliation(s)
- Jelena Mijatovic
- Division of Pharmacology and Toxicology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland.
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Airavaara M, Tuomainen H, Piepponen TP, Saarma M, Ahtee L. Effects of repeated morphine on locomotion, place preference and dopamine in heterozygous glial cell line-derived neurotrophic factor knockout mice. GENES BRAIN AND BEHAVIOR 2006; 6:287-98. [PMID: 16879618 DOI: 10.1111/j.1601-183x.2006.00260.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) has been shown to be involved in the maintenance of striatal dopaminergic neurons. Neurotrophic factors are crucial for the plasticity of central nervous system and may be involved in long-term responses to drug exposure. To study the effects of reduced GDNF on dopaminergic behaviour related to addiction, we compared the effects of morphine on locomotor activity, conditioned place preference (CPP) and extracellular accumbal dopamine in heterozygous GDNF knockout mice (GDNF+/-) with those in their wild-type (Wt) littermates. When morphine 30 mg/kg was administered daily for 4 days, tolerance developed towards its locomotor stimulatory action only in the GDNF+/- mice. A morphine 5 mg/kg challenge dose stimulated locomotor activity only in the GDNF+/- mice withdrawn for 96 h from repeated morphine treatment, whereas clear and similar sensitization of the locomotor response was seen after a 10 mg/kg challenge dose in mice of both genotypes. Morphine-induced CPP developed initially similarly in Wt and GDNF+/- mice, but it lasted longer in the Wt mice. The small challenge dose of morphine increased accumbal dopamine output slightly more in the GDNF+/- mice than in the Wt mice, but doubling the challenge dose caused a dose-dependent response only in the Wt mice. In addition, repeated morphine treatment counteracted the increase in the accumbal extracellular dopamine concentration we previously found in drug-naive GDNF+/- mice. Thus, reduced endogenous GDNF level alters the dopaminergic behavioural effects to repeatedly administered morphine, emphasizing the involvement of GDNF in the neuroplastic changes related to long-term effects of drugs of abuse.
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Affiliation(s)
- M Airavaara
- Division of Pharmacology and Toxicology, Faculty of Pharmacy, University of Helsinki, Finland.
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