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Nature Jul 2023The specific loss of midbrain dopamine neurons (mDANs) causes major motor dysfunction in Parkinson's disease, which makes cell replacement a promising therapeutic...
The specific loss of midbrain dopamine neurons (mDANs) causes major motor dysfunction in Parkinson's disease, which makes cell replacement a promising therapeutic approach. However, poor survival of grafted mDANs remains an obstacle to successful clinical outcomes. Here we show that the surgical procedure itself (referred to here as 'needle trauma') triggers a profound host response that is characterized by acute neuroinflammation, robust infiltration of peripheral immune cells and brain cell death. When midbrain dopamine (mDA) cells derived from human induced pluripotent stem (iPS) cells were transplanted into the rodent striatum, less than 10% of implanted tyrosine hydroxylase (TH) mDANs survived at two weeks after transplantation. By contrast, TH grafted cells mostly survived. Notably, transplantation of autologous regulatory T (T) cells greatly modified the response to needle trauma, suppressing acute neuroinflammation and immune cell infiltration. Furthermore, intra-striatal co-transplantation of T cells and human-iPS-cell-derived mDA cells significantly protected grafted mDANs from needle-trauma-associated death and improved therapeutic outcomes in rodent models of Parkinson's disease with 6-hydroxydopamine lesions. Co-transplantation with T cells also suppressed the undesirable proliferation of TH grafted cells, resulting in more compact grafts with a higher proportion and higher absolute numbers of TH neurons. Together, these data emphasize the importance of the initial inflammatory response to surgical injury in the differential survival of cellular components of the graft, and suggest that co-transplanting autologous T cells effectively reduces the needle-trauma-induced death of mDANs, providing a potential strategy to achieve better clinical outcomes for cell therapy in Parkinson's disease.
Topics: Humans; Dopamine; Dopaminergic Neurons; Mesencephalon; Neuroinflammatory Diseases; Parkinson Disease; Tyrosine 3-Monooxygenase; T-Lymphocytes, Regulatory; Cell- and Tissue-Based Therapy; Animals; Mice; Rats; Oxidopamine; Graft Survival; Cell Death; Induced Pluripotent Stem Cells; Neostriatum; Time Factors; Cell Proliferation; Treatment Outcome
PubMed: 37438521
DOI: 10.1038/s41586-023-06300-4 -
Cell Reports Jun 2023Disturbed motor control is a hallmark of Parkinson's disease (PD). Cortico-striatal synapses play a central role in motor learning and adaption, and brain-derived...
Disturbed motor control is a hallmark of Parkinson's disease (PD). Cortico-striatal synapses play a central role in motor learning and adaption, and brain-derived neurotrophic factor (BDNF) from cortico-striatal afferents modulates their plasticity via TrkB in striatal medium spiny projection neurons (SPNs). We studied the role of dopamine in modulating the sensitivity of direct pathway SPNs (dSPNs) to BDNF in cultures of fluorescence-activated cell sorting (FACS)-enriched D1-expressing SPNs and 6-hydroxydopamine (6-OHDA)-treated rats. DRD1 activation causes enhanced TrkB translocation to the cell surface and increased sensitivity for BDNF. In contrast, dopamine depletion in cultured dSPN neurons, 6-OHDA-treated rats, and postmortem brain of patients with PD reduces BDNF responsiveness and causes formation of intracellular TrkB clusters. These clusters associate with sortilin related VPS10 domain containing receptor 2 (SORCS-2) in multivesicular-like structures, which apparently protects them from lysosomal degradation. Thus, impaired TrkB processing might contribute to disturbed motor function in PD.
Topics: Animals; Humans; Rats; Brain-Derived Neurotrophic Factor; Corpus Striatum; Dopamine; Medium Spiny Neurons; Oxidopamine; Parkinson Disease; Receptor, trkB; Receptors, Dopamine D1
PubMed: 37252844
DOI: 10.1016/j.celrep.2023.112575 -
Cell Reports. Medicine Oct 2023Dyskinesia is involuntary movement caused by long-term medication with dopamine-related agents: the dopamine agonist 3,4-dihydroxy-L-phenylalanine (L-DOPA) to treat...
Dyskinesia is involuntary movement caused by long-term medication with dopamine-related agents: the dopamine agonist 3,4-dihydroxy-L-phenylalanine (L-DOPA) to treat Parkinson's disease (L-DOPA-induced dyskinesia [LID]) or dopamine antagonists to treat schizophrenia (tardive dyskinesia [TD]). However, it remains unknown why distinct types of medications for distinct neuropsychiatric disorders induce similar involuntary movements. Here, we search for a shared structural footprint using magnetic resonance imaging-based macroscopic screening and super-resolution microscopy-based microscopic identification. We identify the enlarged axon terminals of striatal medium spiny neurons in LID and TD model mice. Striatal overexpression of the vesicular gamma-aminobutyric acid transporter (VGAT) is necessary and sufficient for modeling these structural changes; VGAT levels gate the functional and behavioral alterations in dyskinesia models. Our findings indicate that lowered type 2 dopamine receptor signaling with repetitive dopamine fluctuations is a common cause of VGAT overexpression and late-onset dyskinesia formation and that reducing dopamine fluctuation rescues dyskinesia pathology via VGAT downregulation.
Topics: Mice; Animals; Dopamine Agonists; Levodopa; Dopamine; Antiparkinson Agents; Parkinsonian Disorders; Dyskinesia, Drug-Induced; Oxidopamine; gamma-Aminobutyric Acid
PubMed: 37774703
DOI: 10.1016/j.xcrm.2023.101208 -
Journal of Extracellular Vesicles Nov 2023Extracellular vesicles (EVs) play a crucial role in intercellular communication, participating in the paracrine trophic support or in the propagation of toxic molecules,...
Extracellular vesicles (EVs) play a crucial role in intercellular communication, participating in the paracrine trophic support or in the propagation of toxic molecules, including proteins. RTP801 is a stress-regulated protein, whose levels are elevated during neurodegeneration and induce neuron death. However, whether RTP801 toxicity is transferred trans-neuronally via EVs remains unknown. Hence, we overexpressed or silenced RTP801 protein in cultured cortical neurons, isolated their derived EVs (RTP801-EVs or shRTP801-EVs, respectively), and characterized EVs protein content by mass spectrometry (MS). RTP801-EVs toxicity was assessed by treating cultured neurons with these EVs and quantifying apoptotic neuron death and branching. We also tested shRTP801-EVs functionality in the pathologic in vitro model of 6-Hydroxydopamine (6-OHDA). Expression of RTP801 increased the number of EVs released by neurons. Moreover, RTP801 led to a distinct proteomic signature of neuron-derived EVs, containing more pro-apoptotic markers. Hence, we observed that RTP801-induced toxicity was transferred to neurons via EVs, activating apoptosis and impairing neuron morphology complexity. In contrast, shRTP801-EVs were able to increase the arborization in recipient neurons. The 6-OHDA neurotoxin elevated levels of RTP801 in EVs, and 6-OHDA-derived EVs lost the mTOR/Akt signalling activation via Akt and RPS6 downstream effectors. Interestingly, EVs derived from neurons where RTP801 was silenced prior to exposing them to 6-OHDA maintained Akt and RPS6 transactivation in recipient neurons. Taken together, these results suggest that RTP801-induced toxicity is transferred via EVs, and therefore, it could contribute to the progression of neurodegenerative diseases, in which RTP801 is involved.
Topics: Transcription Factors; Oxidopamine; Proteomics; Proto-Oncogene Proteins c-akt; Extracellular Vesicles
PubMed: 37932242
DOI: 10.1002/jev2.12378 -
Journal of Ethnopharmacology Mar 2024Piper longum L., a medicinal and food homologous herb, has a traditional history of use in treating gastrointestinal and neurological disorders. Piperine (PIP) the main...
ETHNOPHARMACOLOGICAL RELEVANCE
Piper longum L., a medicinal and food homologous herb, has a traditional history of use in treating gastrointestinal and neurological disorders. Piperine (PIP) the main alkaloid of P. longum, exists neuroprotective effects on various animal models of Parkinson's disease (PD). Nevertheless, the underlying mechanism, particularly the role of PIP in promoting gut-brain autophagy for α-Synuclein (α-Syn) degradation in PD, remains incompletely understood.
AIM OF THE STUDY
To explore the role of PIP in regulating the gut-brain autophagy signaling pathway to reduce α-Syn levels in both the colon and substantia nigra (SN) of PD model rats.
MATERIALS AND METHODS
Behavioral experiments were conducted to assess the impact of PIP on 6-hydroxydopamine (6-OHDA)-induced PD rats. The intestinal microbiome composition and intestinal metabolites were analyzed by metagenomics and GC-MS/MS. The auto-phagosomes were visualized by transmission electron microscopy. Immunohistochemistry, immunofluorescence, and western blotting were performed to assess the levels of tyrosine hydroxylase (TH), α-Syn, LC3II/LC3I, p62, and the PI3K/AKT/mTOR pathway in both the SN and colon of the rats. The pathway-related inhibitor and agonist were used to verify the autophagy mechanism in the SH-SY5Y cells overexpressing A53T mutant α-Syn (A53T-α-Syn).
RESULTS
PIP improved autonomic movement and gastrointestinal dysfunctions, reduced α-Syn aggregation and attenuated the loss of dopaminergic neurons in 6-OHDA-induced PD rats. After oral administration of PIP, the radio of LC3II/LC3I increased and the expression of p62 was degraded, as well as the phosphorylation levels of PI3K, AKT and mTOR decreased in the SN and colon of rats. The effect of PIP on reducing A53T-α-Syn through the activation of the PI3K/AKT/mTOR-mediated autophagy pathway was further confirmed in A53T-α-Syn transgenic SH-SY5Y cells. This effect could be inhibited by the autophagy inhibitor bafilomycin A1 and the PI3K agonist 740 Y-P.
CONCLUSIONS
Our findings suggested that PIP could protect neurons by activating autophagy to degrade α-Syn in the SN and colon, which were related to the suppression of PIP on the activation of PI3K/AKT/mTOR signaling pathway.
Topics: Rats; Humans; Animals; Parkinson Disease; alpha-Synuclein; Proto-Oncogene Proteins c-akt; Phosphatidylinositol 3-Kinases; Oxidopamine; Tandem Mass Spectrometry; Neuroblastoma; Alkaloids; TOR Serine-Threonine Kinases; Brain; Autophagy; Piperidines; Benzodioxoles; Polyunsaturated Alkamides
PubMed: 38158101
DOI: 10.1016/j.jep.2023.117628 -
International Journal of Molecular... Jul 2023Parkinson's Disease (PD), treated with the dopamine precursor l-3,4-dihydroxyphenylalanine (L-DOPA), displays motor and non-motor orofacial manifestations. We...
Parkinson's Disease (PD), treated with the dopamine precursor l-3,4-dihydroxyphenylalanine (L-DOPA), displays motor and non-motor orofacial manifestations. We investigated the pathophysiologic mechanisms of the lateral pterygoid muscles (LPMs) and the trigeminal system related to PD-induced orofacial manifestations. A PD rat model was produced by unilateral injection of 6-hydroxydopamine into the medial forebrain bundle. Abnormal involuntary movements (dyskinesia) and nociceptive responses were determined. We analyzed the immunodetection of Fos-B and microglia/astrocytes in trigeminal and facial nuclei and morphological markers in the LPMs. Hyperalgesia response was increased in hemiparkinsonian and dyskinetic rats. Hemiparkinsonism increased slow skeletal myosin fibers in the LPMs, while in the dyskinetic ones, these fibers decreased in the contralateral side of the lesion. Bilateral increased glycolytic metabolism and an inflammatory muscle profile were detected in dyskinetic rats. There was increased Fos-B expression in the spinal nucleus of lesioned rats and in the motor and facial nucleus in L-DOPA-induced dyskinetic rats in the contralateral side of the lesion. Glial cells were increased in the facial nucleus on the contralateral side of the lesion. Overall, spinal trigeminal nucleus activation may be associated with orofacial sensorial impairment in Parkinsonian rats, while a fatigue profile on LPMs is suggested in L-DOPA-induced dyskinesia when the motor and facial nucleus are activated.
Topics: Rats; Animals; Levodopa; Dyskinesia, Drug-Induced; Corpus Striatum; Parkinsonian Disorders; Parkinson Disease; Oxidopamine; Brain Stem; Disease Models, Animal; Antiparkinson Agents
PubMed: 37569642
DOI: 10.3390/ijms241512270 -
BMC Biology Nov 2023Diets high in saturated fat and sugar, termed "Western diets," have been associated with several negative health outcomes, including increased risk for neurodegenerative...
BACKGROUND
Diets high in saturated fat and sugar, termed "Western diets," have been associated with several negative health outcomes, including increased risk for neurodegenerative disease. Parkinson's disease (PD) is the second most prevalent neurodegenerative disease and is characterized by the progressive death of dopaminergic neurons in the brain. We build upon previous work characterizing the impact of high-sugar diets in Caenorhabditis elegans to mechanistically evaluate the relationship between high-sugar diets and dopaminergic neurodegeneration.
RESULTS
Adult high-glucose and high-fructose diets, or exposure from day 1 to 5 of adulthood, led to increased lipid content, shorter lifespan, and decreased reproduction. However, in contrast to previous reports, we found that adult chronic high-glucose and high-fructose diets did not induce dopaminergic neurodegeneration alone and were protective from 6-hydroxydopamine (6-OHDA) induced degeneration. Neither sugar altered baseline electron transport chain function and both increased vulnerability to organism-wide ATP depletion when the electron transport chain was inhibited, arguing against energetic rescue as a basis for neuroprotection. The induction of oxidative stress by 6-OHDA is hypothesized to contribute to its pathology, and high-sugar diets prevented this increase in the soma of the dopaminergic neurons. However, we did not find increased expression of antioxidant enzymes or glutathione levels. Instead, we found evidence suggesting downregulation of the dopamine reuptake transporter dat-1 that could result in decreased 6-OHDA uptake.
CONCLUSIONS
Our work uncovers a neuroprotective role for high-sugar diets, despite concomitant decreases in lifespan and reproduction. Our results support the broader finding that ATP depletion alone is insufficient to induce dopaminergic neurodegeneration, whereas increased neuronal oxidative stress may drive degeneration. Finally, our work highlights the importance of evaluating lifestyle by toxicant interactions.
Topics: Animals; Humans; Caenorhabditis elegans; Oxidopamine; Dopamine; Neurodegenerative Diseases; Nerve Degeneration; Dopaminergic Neurons; Adenosine Triphosphate; Sugars; Fructose; Glucose; Disease Models, Animal
PubMed: 37950228
DOI: 10.1186/s12915-023-01733-9 -
Biochimica Et Biophysica Acta.... Dec 2023Parkinson's disease (PD) is a neurodegenerative disease. Repetitive transcranial magnetic stimulation (rTMS) is a therapeutic tool in PD. High-throughput sequencing was...
Parkinson's disease (PD) is a neurodegenerative disease. Repetitive transcranial magnetic stimulation (rTMS) is a therapeutic tool in PD. High-throughput sequencing was performed to screen potential therapeutic targets in unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats. The candidate gene, Clec7a, was screened out and validated. Clec7a is a pattern recognition receptor involved in neuroinflammation. The higher expression of Clec7a was observed in the substantia nigra (SN) and striatum of PD rats with dopaminergic neurons damage and was mainly localized in the microglial. Adeno-associated virus (AAV)-mediated specific knockdown of Clec7a in microglial alleviated 6-OHDA induced motor deficits and nigrostriatal dopaminergic neuron damage of rats, as evidenced by the increase of tyrosine hydroxylase (TH) -positive neurons in SN, as well as dopaminergic nerve fibers in the striatum. Clec7a knockdown restrained the neuroinflammation by suppressing inflammatory factors (IFN-γ, TNF-α, IL-1β, IL-18, and IL-6) release in SN, which might result from enhanced Arg-1 expression (M2 polarization) and defective inducible nitric oxide synthase (iNOS) expression (M1 polarization). The same phenomena were also observed in the LPS inflammatory rat model of PD. In vitro, α-synuclein fibrils induced upregulation of Clec7a expression and microglia polarization to a pro-inflammatory state of BV2 cells, leading to increased release of cytokines. However, Clec7a knockdown reversed those changes and induced a shift to an anti-inflammatory phenotype in BV2 cells. In conclusion, our study suggested that Clec7a was involved in PD pathogenesis, and its inhibition might protect rats from PD by depressing neuroinflammation through microglial polarization.
Topics: Rats; Animals; Parkinson Disease; Neurodegenerative Diseases; Neuroinflammatory Diseases; Transcranial Magnetic Stimulation; Oxidopamine; Dopaminergic Neurons
PubMed: 37495085
DOI: 10.1016/j.bbadis.2023.166814 -
Journal of Neurochemistry Dec 2023L-Dopa, while treating motor symptoms of Parkinson's disease, can lead to debilitating L-Dopa-induced dyskinesias, limiting its use. To investigate the causative...
L-Dopa, while treating motor symptoms of Parkinson's disease, can lead to debilitating L-Dopa-induced dyskinesias, limiting its use. To investigate the causative relationship between neuro-inflammation and dyskinesias, we assessed if striatal M1 and M2 microglia numbers correlated with dyskinesia severity and whether the anti-inflammatories, minocycline and indomethacin, reverse these numbers and mitigate against dyskinesia. In 6-OHDA lesioned mice, we used stereology to assess numbers of striatal M1 and M2 microglia populations in non-lesioned (naïve) and lesioned mice that either received no L-Dopa (PD), remained non-dyskinetic even after L-Dopa (non-LID) or became dyskinetic after L-Dopa treatment (LID). We also assessed the effect of minocycline/indomethacin treatment on striatal M1 and M2 microglia and its anti-dyskinetic potential via AIMs scoring. We report that L-Dopa treatment leading to LIDs exacerbates activated microglia numbers beyond that associated with the PD state; the severity of LIDs is strongly correlated to the ratio of the striatal M1 to M2 microglial numbers; in non-dyskinetic mice, there is no M1/M2 microglia ratio increase above that seen in PD mice; and reducing M1/M2 microglia ratio using anti-inflammatories is anti-dyskinetic. Parkinson's disease is associated with increased inflammation, but this is insufficient to underpin dyskinesia. Given that L-Dopa-treated non-LID mice show the same ratio of M1/M2 microglia as PD mice that received no L-Dopa, and, given minocycline/indomethacin reduces both the ratio of M1/M2 microglia and dyskinesia severity, our data suggest the increased microglial M1/M2 ratio that occurs following L-Dopa treatment is a contributing cause of dyskinesias.
Topics: Rats; Mice; Animals; Levodopa; Parkinson Disease; Microglia; Minocycline; Rats, Sprague-Dawley; Corpus Striatum; Dyskinesias; Oxidopamine; Inflammation; Anti-Inflammatory Agents; Indomethacin; Antiparkinson Agents
PubMed: 37916541
DOI: 10.1111/jnc.15993 -
International Journal of Molecular... Jul 2023Danshen has been widely used for the treatment of central nervous system diseases. We investigated the effect of dihydroisotanshinone I (DT), a compound extracted from...
Danshen has been widely used for the treatment of central nervous system diseases. We investigated the effect of dihydroisotanshinone I (DT), a compound extracted from Danshen, as well as the corresponding mechanisms in an in vitro-based 6-OHDA-induced Parkinson's disease (PD) model. SH-SY5Y human neuroblastoma cell lines were pretreated with 6-hydroxydopamine (6-OHDA) and challenged with DT. Subsequently, the cell viability and levels of reactive oxygen species (ROS) and caspase-3 were analyzed. The effect of DT on the 6-OHDA-treated SH-SY5Y cells and the expression of the core circadian clock genes were measured using a real-time quantitative polymerase chain reaction. Our results indicated that DT attenuated the 6-OHDA-induced cell death in the SH-SY5Y cells and suppressed ROS and caspase-3. Moreover, DT reversed both the RNA and protein levels of and in the 6-OHDA-treated SH-SY5Y cells. Additionally, the inhibitor attenuated the effect of DT on and reduced the cell viability. The DT and activators activated and , and then reduced the death of the SH-SY5Y cells damaged by 6-OHDA. SIRT1 silencing was enhanced by DT and resulted in a BMAL1 downregulation and a reduction in cell viability. In conclusion, our investigation suggested that DT reduces cell apoptosis, including an antioxidative effect due to a reduction in ROS, and regulates the circadian genes by enhancing SIRT1 and suppressing BMAL1. DT may possess novel therapeutic potential for PD in the future, but further in vivo studies are still needed.
Topics: Humans; Parkinson Disease; Reactive Oxygen Species; Oxidopamine; Caspase 3; Sirtuin 1; ARNTL Transcription Factors; Cell Line, Tumor; Neuroblastoma; Apoptosis; Neuroprotective Agents
PubMed: 37446264
DOI: 10.3390/ijms241311088