Extracellular vesicles contain filamentous alpha-synuclein and facilitate the propagation of Parkinson's pathology.

Parkinson's disease (PD) is characterized by the pathological deposition of a-synuclein (a-syn) inclusions, known as Lewy bodies/neurites. Emerging evidence suggests that extracellular vesicles (EVs) play a role in facilitating the spreading of Lewy pathology between the peripheral nervous system and the central nervous system. We analyzed serum EVs obtained from patients with PD (n = 142), multiple system atrophy (MSA) (n = 18), progressive supranuclear palsy (PSP) (n = 28), rapid eye movement sleep behavior disorder (n = 31), and controls (n = 105). While we observed a significant reduction in the number of EVs in PD compared to controls (p = 0.006), we also noted a substantial increase in filamentous α-synuclein within EVs in PD compared to controls (p < 0.0001), MSA (0.012), and PSP (p = 0.03). Further analysis unveiled the role of EVs in facilitating the transmission of filamentous α-synuclein between neurons and from peripheral blood to the CNS. These findings highlight the potential utility of serum α-synuclein filaments within EVs as diagnostic markers for synucleinopathies and underscore the significance of EVs in promoting the dissemination of filamentous α-synuclein throughout the entire body.

Reversible Pisa syndrome caused by chronic subdural hematoma in a patient with Parkinson's disease: a case report.

BACKGROUND: Pisa syndrome (PS), characterized by lateral trunk flexion, is quite common in patients with Parkinson's disease (PD). Patients with PS are older and have a significantly longer disease duration, more severe motor phenotype, ongoing combined treatment with levodopa and dopamine agonists, and higher levodopa equivalent daily dose. We describe here, to the best of our knowledge, the first case of a woman with PD who developed acute-onset PS caused by chronic subdural hematoma (CSDH). CASE PRESENTATION: A 70-year-old woman developed acute-onset lateral flexion of her trunk to the left side while standing, and she was admitted to our hospital. One month before, she had a mild head trauma with loss of consciousness. At 65 years of age, she noticed difficulty with walking and clumsiness with her hands. She was diagnosed as having PD (Hoehn and Yahr stage 2) and levodopa was initiated. Her symptoms were markedly improved. At 67 years of age, she developed orthostatic hypotension and was treated sequentially with fluids, compression stockings, and midodrine. Urgently performed brain computed tomography (CT) showed a CSDH in the right hemisphere resulting in a marked compression of the hemisphere. After surgical evacuation, her PS disappeared. She has fully recovered to her preoperative level of function. CONCLUSION: The present case provides a valuable insight, that is, the mesial frontal lobe and its connections from the posterior parietal cortex play crucial roles in maintaining the body schema and in the pathophysiology of PS. This case suggests that CSDH should be considered when clinicians examine acute-onset PS, even in patients with neurodegenerative disorders such as PD. Appropriate patient triage and timely neurosurgical intervention should be considered.

Astrocytes Protect Human Dopaminergic Neurons from α-Synuclein Accumulation and Propagation.

The pathologic hallmark of Parkinson's disease is the accumulation of α-synuclein-containing Lewy bodies/neurites almost exclusively in neurons, and rarely in glial cells. However, emerging evidence suggests that glia such as astrocytes play an important role in the development of α-synuclein pathology. Using induced pluripotent stem-derived dopaminergic neurons and astrocytes from healthy subjects and patients carrying mutations in lysosomal ATP13A2, a monogenic form of synucleinopathy, we found that astrocytes rapidly internalized α-synuclein, and exhibited higher lysosomal degradation rates compared with neurons. Moreover, coculturing astrocytes and neurons led to decreased accumulation of α-synuclein in neurons and consequently diminished interneuronal transfer of α-synuclein. These protective functions of astrocytes were attenuated by ATP13A2 deficiency, suggesting that the loss of ATP13A2 function in astrocytes at least partially contributes to neuronal α-synuclein pathology. Together, our results highlight the importance of lysosomal function in astrocytes in the pathogenesis of synucleinopathies.SIGNIFICANCE STATEMENT While most neurodegenerative disorders are characterized by the accumulation of aggregated mutant proteins exclusively in neurons, the contribution of glial cells in this process remains poorly explored. Here, we demonstrate that astrocytes contribute to the removal of extracellular α-synuclein and that disruption of this pathway caused by mutations in the Parkinson's disease-linked gene ATP13A2 result in α-synuclein accumulation in human dopaminergic neurons. We found that astrocytes also protect neurons from α-synuclein propagation, whereas ATP13A2 deficiency in astrocytes compromises this protective function. These results highlight astrocyte-mediated α-synuclein clearance as a potential therapeutic target in disorders characterized by the accumulation of α-synuclein, including Parkinson's disease.

Increased Lysosomal Exocytosis Induced by Lysosomal Ca2+ Channel Agonists Protects Human Dopaminergic Neurons from α-Synuclein Toxicity.

The accumulation of misfolded proteins is a common pathological feature of many neurodegenerative disorders, including synucleinopathies such as Parkinson's disease (PD), which is characterized by the presence of α-synuclein (α-syn)-containing Lewy bodies. However, although recent studies have investigated α-syn accumulation and propagation in neurons, the molecular mechanisms underlying α-syn transmission have been largely unexplored. Here, we examined a monogenic form of synucleinopathy caused by loss-of-function mutations in lysosomal ATP13A2/PARK9. These studies revealed that lysosomal exocytosis regulates intracellular levels of α-syn in human neurons. Loss of PARK9 function in patient-derived dopaminergic neurons disrupted lysosomal Ca2+ homeostasis, reduced lysosomal Ca2+ storage, increased cytosolic Ca2+, and impaired lysosomal exocytosis. Importantly, this dysfunction in lysosomal exocytosis impaired α-syn secretion from both axons and soma, promoting α-syn accumulation. However, activation of the lysosomal Ca2+ channel transient receptor potential mucolipin 1 (TRPML1) was sufficient to upregulate lysosomal exocytosis, rescue defective α-syn secretion, and prevent α-syn accumulation. Together, these results suggest that intracellular α-syn levels are regulated by lysosomal exocytosis in human dopaminergic neurons and may represent a potential therapeutic target for PD and other synucleinopathies.SIGNIFICANCE STATEMENT Parkinson's disease (PD) is the second most common neurodegenerative disease linked to the accumulation of α-synuclein (α-syn) in patient neurons. However, it is unclear what the mechanism might be. Here, we demonstrate a novel role for lysosomal exocytosis in clearing intracellular α-syn and show that impairment of this pathway by mutations in the PD-linked gene ATP13A2/PARK9 contributes to α-syn accumulation in human dopaminergic neurons. Importantly, upregulating lysosomal exocytosis by increasing lysosomal Ca2+ levels was sufficient to rescue defective α-syn secretion and accumulation in patient neurons. These studies identify lysosomal exocytosis as a potential therapeutic target in diseases characterized by the accumulation of α-syn, including PD.

Shared Metabolic Profile of Caffeine in Parkinsonian Disorders.

OBJECTIVE: The objective of this study was to determine comprehensive metabolic changes of caffeine in the serum of patients with parkinsonian disorders including Parkinson's disease (PD), progressive supranuclear palsy (PSP), and multiple system atrophy (MSA) and to compare this with healthy control serum. METHODS: Serum levels of caffeine and its 11 downstream metabolites from independent double cohorts consisting of PD (n = 111, 160), PSP (n = 30, 19), MSA (n = 23, 17), and healthy controls (n = 43, 31) were examined by liquid chromatography-mass spectrometry. The association of each metabolite with clinical parameters and medication was investigated. Mutations in caffeine-associated genes were investigated by direct sequencing. RESULTS: A total of 9 metabolites detected in more than 50% of participants in both cohorts were decreased in 3 parkinsonian disorders compared with healthy controls without any significant association with age at sampling, sex, or disease severity (Hoehn and Yahr stage and Unified Parkinson's Disease Rating Scale motor section) in PD, and levodopa dose or levodopa equivalent dose in PSP and MSA. Of the 9 detected metabolites, 8 in PD, 5 in PSP, and 3 in MSA were significantly decreased in both cohorts even after normalizing to daily caffeine consumption. No significant genetic variations in CYP1A2 or CYP2E1 were detected when compared with controls. CONCLUSION: Serum caffeine metabolic profiles in 3 parkinsonian diseases show a high level of overlap, indicative of a common potential mechanism such as caffeine malabsorption from the small intestine, hypermetabolism, increased clearance of caffeine, and/or reduced caffeine consumption. © 2020 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

CD8+ T-cell encephalitis mimicking PRES in AIDS: a case report.

BACKGROUND: Diverse mechanisms including infections, autoimmune inflammatory reactions, neoplasms, and degeneration are involved in the central nervous system in cases of acquired immune deficiency syndrome. In such cases, it is difficult to determine the precise pathogenesis by radiological examination and laboratory testing. CASE PRESENTATION: We report a 37-year-old Japanese woman who had untreated hypertension and gender identity disorder and had been taking testosterone injections since she was 19 years old. She developed a headache and visual field deficits together with elevated blood pressure. According to radiological findings, she was initially suspected as having posterior reversible encephalopathy syndrome in the right parieto-occipital lobe with reversible cerebral vasoconstriction syndrome. Human immunodeficiency virus antibody was positive and the CD4+ T-lymphocyte count was 140 cells/µl. Therefore, antiretroviral therapy was started. Antiretroviral therapy suppressed the activity of acquired immune deficiency syndrome but worsened her visual symptoms and expanding radiological lesions. Brain biopsy led to the diagnosis of CD8+ encephalitis, and she also fulfilled the diagnosis of paradoxical immune reconstitution inflammatory syndrome. Corticosteroid therapy alleviated her symptoms. CONCLUSIONS: This is a rare case of CD8+ encephalitis, with an exacerbation owing to paradoxical immune reconstitution inflammatory syndrome after antiretroviral therapy, which radiologically mimicked posterior reversible encephalopathy syndrome. Corticosteroid therapy was effective; thus, it is important to provide a pathological diagnosis in such cases.

Cytomegalovirus-associated encephalomyelitis in an immunocompetent adult: a two-stage attack of direct viral and delayed immune-mediated invasions. case report.

BACKGROUND: It is clinically rare to find cytomegalovirus (CMV)-associated encephalomyelitis in immunocompetent adults. Here, we present the case of an adult patient who developed acute transverse myelitis that was followed by immune-mediated disseminated encephalomyelitis. CASE PRESENTATION: A 38-year-old man developed acute paraplegia with paresthesia below the level of the T7-8 dermatome. Both brain and spinal cord MRIs performed at admission appeared normal. Corticosteroid therapy was initiated, with the later addition of high-dose intravenous immunoglobulins. After polymerase chain reaction analysis indicated the presence of CMV DNA in his cerebrospinal fluid (CSF), anti-viral therapy was added. Forty days after symptom onset, despite an initial positive response to this therapy, he developed dysarthria and truncal ataxia. Repeated magnetic resonance imaging scans demonstrated progressively expanding lesions involving not only the spinal cord but also the cerebral white matter, suggestive of extensive immune-mediated demyelination involving the central nervous system (CNS), as is observed in acute disseminated encephalomyelitis (ADEM). CONCLUSION: This case report underscores the importance of careful patient observation following the initial diagnosis of a CMV-associated CNS infection, such as transverse myelitis, on the possibility that post-infectious ADEM may appear.

Good's syndrome with opportunistic infection of the central nervous system: a case report.

BACKGROUND: Immunodeficiency with a thymoma (Good's syndrome) is a rare condition occurring in patients with adult-onset hypogammaglobulinemia that is progressive after the removal of thymoma. Recently, we encountered a patient with Good's syndrome who suddenly developed opportunistic encephalitis 4 years after the resection of thymoma without a history of infectious complications. CASE PRESENTATION: A 58-year-old man, who underwent surgery to remove a thymoma at the age of 54, was admitted because of speech difficulties. A brain MRI showed multiple lesions involving the frontal lobes, but the CSF finding was normal. Acyclovir was empirically administered, and fever as well as his neurological symptoms fully recovered within a few days. However, 1 week after admission, motor aphasia and mild right hemiparesis reappeared. MRI showed that the lesion involving the left cingulate gyrus expanded in size, and revealed an abnormal signal intensity lesion in the left corona radiata. Laboratory examination found increased CMV pp65 antigen-positive lymphocytes in serum. Antiviral therapy using ganciclovir and immunoglobulin replacement therapy was started. The patient has since been free from any neurological symptoms for 1 year, and lesions demonstrated by MRI are gradually improving. CONCLUSION: Early recognition of this rare condition and prompt initiation of therapy are crucially important. Awareness of immunodeficiency in a patient after removal of thymoma may help neurologists to consider the possibility that opportunistic infection may be the cause of cerebral lesions.

Subacute Progressive Hearing Loss and Lower Body Parkinsonism in Primary Sjögren's Syndrome.

In primary Sjögren's syndrome, it is extremely rare to observe subacute progressive lower-body parkinsonism with severe sensory hearing loss responsive to corticosteroid therapy. Sjögren's syndrome can cause heterogeneous symptoms; therefore, its diagnosis and introduction of treatment are prone to be delayed, particularly in cases without sicca symptoms or seronegative cases, which are more likely to be seen in patients with neurological complications. This report may help clinicians identify atypical early neurological symptoms in primary Sjögren's syndrome.

Comorbid alpha synucleinopathies in idiopathic normal pressure hydrocephalus.

OBJECTIVE: This study aimed to determine the prevalence and clinical features of Parkinson's disease (PD)/PD dementia (PD/PDD) or dementia with Lewy bodies (DLB) in idiopathic normal pressure hydrocephalus (iNPH). METHODS: Patients with iNPH who were admitted to the Department of Neurology, Juntendo University School of Medicine over the past 10 years have been retrospectively analyzed. The diagnosis of iNPH and concomitant PD/PDD or DLB was established using diagnostic criteria. Motor symptoms were assessed by the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) III. 123I-ioflupane single-photon emission computed tomography (DaT-SPECT) and cerebrospinal fluid (CSF) real-time quaking-induced conversion (RT-QuIC)-based assay were performed for alpha synuclein aggregation. RESULTS: Overall, 79 patients met the criteria for iNPH, of which 34 developed iNPH without accompanying disorders (iNPHa; 43%), 23 developed iNPH with comorbid PD/PDD (iNPHc + PD/PDD; 29.1%), and 8 developed iNPH with comorbid DLB (iNPHc + DLB; 10.1%). Significant differences in facial expansion and upper-limb parkinsonism were observed with a comorbidity of either PD/PDD or DLB. The specific binding ratio (SBR) of DaTscan was reduced in iNPHa (p = 0.02), but it reduced further with comorbid PD/PDD (p < 0.01) or DLB (p < 0.01). RT-QuIC was positive for all 13 comorbid PD/PDD and negative for all 19 iNPHa. CONCLUSION: These results highlight that synucleinopathies coexist with iNPH. These can be differentiated by performing DaTscan and RT-QuIC, which can affect its clinical features.

Genotype-phenotype correlation of Parkinson's disease with PRKN variants.

To investigate the prevalence and genotype-phenotype correlations of parkin RBR E3 ubiquitin protein ligase (PRKN) variants in Parkinson's disease (PD), we first included 2,527 patients with PD. Through the defined selection, we enrolled 2,322 patients, including 1,204 with familial and 1,118 with sporadic PD. We identified 242 patients harboring PRKN variants, which were thought to be susceptibility factors, comprising 137 patients with familial and 105 with sporadic PD; among the 26 identified variants, 13 were novel. We divided our cohort into 2 groups: heterozygote (hereafter called one-allele) and homozygote or compound heterozygote (hereafter called two-allele). The patients with two-allele were significantly younger at onset than those with one-allele. Six families harbored the complex forms of one- and two-allele in different individuals of the same family. The presence of two-allele reflected more frequent normal values of [123I] metaiodobenzylguanidine myocardial scintigraphy. The log-rank test revealed an exacerbation associated with two-allele over 15 years of the disease course. The patients with PRKN variants showed specific symptoms dependent on the number of mutated alleles.

Analysis of α-Synuclein in Exosomes.

Alpha synuclein (α-Syn), a presynaptic protein with unknown function, is accumulated in Lewy bodies/neurites that are one of the hallmark pathologies of Parkinson's disease (PD). Missense or multiplication mutations in SNCA, which codes α-Syn, result in a genetic form of PD, further indicating the involvement of α-Syn in PD pathogenesis. Recent pathological and experimental studies suggest that α-Syn possesses a secretory feature, as it is detected in the culture media, in the cerebrospinal fluid, and even in the blood. Secreted α-Syn can spread throughout the body and invade the CNS, disseminating the α-Syn associated pathology. Exosomes are small extracellular vesicles that carry many proteins, lipids, or miRNA. We and others have discovered α-Syn in exosomes and revealed that exosomes may regulate intracellular α-Syn levels by transporting outside the cells. In this chapter, we describe a protocol to measure α-Syn levels in exosomes.

Clinical manifestations of Parkinson's disease harboring VPS35 retromer complex component p.D620N with long-term follow-up.

INTRODUCTION: To identify and investigate patients with Parkinson's disease (PD) harboring VPS35 variants in Japan. METHODS: Using targeted gene panel screening, we analyzed 393 familial, 294 young-onset, and 52 late-onset sporadic PD patients derived from the Juntendo PD DNA bank, and obtained clinical information from the medical records on each patient in whom we found VPS35 p.D620N variants. RESULTS: We identified VPS35 p.D620N in three new patients: two patients with familial PD and one patient with sporadic PD. Additionally, we newly confirmed p.D620 from a patient of a family reported previously. The prevalence of familial PD was 0.7% (2/307), young-onset sporadic PD was 0.3% (1/294), and late-onset sporadic PD was 0% (0/52) in our cohort. Combining four patients with p.D620N from our previous reports, haplotype analysis indicated at least two founders in our cohort. Patients commonly showed a slow progression of parkinsonism with onset in middle or late age and mild parkinsonism with good response to levodopa and little cognitive decline even for more than 10 years of disease duration. Psychosis was occurred in two patients. One-half of patients required device-aided therapies such as deep brain stimulation or levodopa-carbidopa intestinal gel. Brain magnetic resonance imaging mostly showed normal findings, even at more than 10 years after onset. 123I-metaiodobenzylguanidine myocardial scintigraphy indicated normal heart-to-mediastinum ratio values among three of four patients. CONCLUSIONS: Patients with VPS35 p.D620N showed distinctive symptoms and neuroimaging. Our findings expand the clinical findings of patients with VPS35 variants.

Demyelinating Peripheral Neuropathy Due to Renal Cell Carcinoma.

Renal cell carcinoma (RCC) patients who develop a paraneoplastic syndrome may present with neuromuscular disorders. We herein report the case of a 50-year-old man who suffered from progressive gait disturbance and muscle weakness. The results of a nerve conduction study fulfilled the criteria of chronic inflammatory demyelinating polyneuropathy. An abdominal CT scan detected RCC, the pathological diagnosis of which was clear cell type. After tumor resection and a single course of intravenous immunoglobulin therapy, the patient's symptoms drastically improved over the course of one year. The patient's neurological symptoms preceded the detection of cancer. A proper diagnosis and the initiation of suitable therapies resulted in a favorable outcome.