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Abstract Tau seed amplification assays (SAAs) directly measure the seeding activity of tau and would therefore be ideal biomarkers for clinical trials targeting seeding-competent tau in Alzheimer’s disease (AD). However, the precise relationship between tau seeding measured by SAA and the levels of pathological forms of tau in the AD brain remains unknown. We developed a new tau SAA based on full-length 0N3R tau with sensitivity in the low fg/ml range and used it to characterize 103 brain samples from three independent cohorts. Tau seeding clearly discriminated between AD and control brain samples. Interestingly, seeding was absent in Progressive Supranuclear Palsy (PSP) putamen, suggesting that our tau SAA did not amplify 4R tau aggregates from PSP brain. The specificity of our tau SAA for AD brain was further supported by analysis of matched hippocampus and cerebellum samples. While seeding was detected in hippocampus from Braak stages I-II, no seeding was present in AD cerebellum that is devoid of tau inclusions. Analysis of 40 middle frontal gyrus samples encompassing all Braak stages showed that tau SAA seeding activity gradually increased with Braak stage. This relationship between seeding activity and the presence of tau inclusions in AD brain was further supported by robust correlations between tau SAA results and the levels of phosphorylated tau212/214, phosphorylated tau181, aggregated tau, and sarkosyl-insoluble tau. Strikingly, we detected tau seeding in the middle frontal gyrus already at Braak stage II-III, suggesting that tau SAA can detect tau pathology earlier than conventional immunohistochemical staining. In conclusion, our data suggest a quantitative relationship between tau seeding activity and pathological forms of tau in the human brain and provides an important basis for further development of tau SAA for accessible human samples.

Background: Anticholinergic adverse effects pose a relevant threat to patients, in particular elderly and cognitively impaired patients. Patients with Parkinsonian syndromes are especially at risk from anticholinergic adverse effects due to the often-required complex drug therapy. Aims: The aim of this study was to evaluate the potential effect of the anticholinergic burden on motor and non-motor symptoms in Parkinson’s disease and atypical Parkinsonian syndromes. Methods: This cross-sectional, monocentric retrospective data analysis included 151 patients with Parkinson’s disease (PD), 63 with progressive supranuclear palsy (PSP), and 36 with multiple system atrophy (MSA). The anticholinergic burden of patients’ medications was determined using two established scores: the Anticholinergic Drug Scale (ADS) and the German Anticholinergic Burden Scale (GABS). These scores were compared between the different diseases and correlated with several disease-specific scores. Results: Anticholinergic burden was higher in patients with PD, in particular, compared to PSP. In the PD group, anticholinergic burden showed a weak correlation with almost all analyzed clinical scores and the number of administered drugs. The UMSARS I and II showed a significant correlation with the anticholinergic burden in MSA patients. In general, the GABS-measured anticholinergic burden was significantly higher compared to the ADS-measured. Conclusions: The calculated anticholinergic burden affected motor and non-motor symptoms in patients with various Parkinsonian syndromes poorly. Since the GABS also contains basic anti-parkinsonian drugs, this score tended to overestimate the anticholinergic burden in patients with Parkinsonian syndromes and, therefore, seemed less appropriate for this application.

Pathogenic variants in the Parkin-gene (PRKN) are among the most common genetic causes of early onset Parkinson's disease (EOPD). Patients with EOPD can present with atypical clinical features and misdiagnosis is frequent. Here, we report a clinical phenotype with atypical signs and symptoms of a 35-year-old male patient with EOPD caused by a compound heterozygous PRKN-gene deletion of exons 2 and 4. After the initial diagnosis of stiff person syndrome, the patient was admitted to our department for a second opinion after 8 years of untreated disease progression. The patient presented with prominent spastic paraparesis pronounced on the right side and hyperreflexia as well as Parkinsonism with rigidity predominantly affecting the upper limbs, bradykinesia, and resting tremor. In the diagnostic assessment, magnetic evoked potentials to the anterior tibial muscles showed a low amplitude on the right side, compatible with pyramidal tract disturbance. However, an MRI of the head and the spine did not show any pathologies or atrophy. A [123I] FP-CIT SPECT scan revealed profoundly and left-pronounced reduced striatal uptake suggesting a neurodegenerative Parkinson's syndrome. Even though an acute levodopa challenge did not show marked improvement of symptoms, the chronic levodopa challenge with up to 450 mg/day significantly reduced the rigidity and bradykinesia. Surprisingly, spastic paraparesis and hyperreflexia diminished under dopaminergic treatment. Finally, genetic analysis by next-generation sequencing via copy number variant analysis (CNV) and multiplex ligation-dependent probe amplification (MLPA) confirmed compound heterozygous deletions of exons 2 and 4 in the PRKN-gene. As presented in this case, the awareness of atypical clinical symptoms of EOPD is essential to prevent misdiagnosis in young patients.

Abstract Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a curative treatment for hematologic malignancies. Acute and chronic graft-versus-host disease (GvHD) are the major immune-mediated complications after alloHSCT. However, there is controversy whether neurologic complications after alloHSCT might represent manifestations of GvHD. We report three patients who acquired distinct, severe immune-mediated peripheral or central nervous system diseases after alloHSCT without other, concomitant GvHD manifestations. One patient had been diagnosed with B-cell chronic lymphocytic leukemia and two patients with high risk myelodysplastic syndrome. Patient #1 presented as LGI1- and GAD-IgG positive immune-mediated encephalitis, patient #2 was diagnosed with MOG-IgG positive encephalomyelitis, and patient #3 had chronic inflammatory polyneuropathy associated with SSA(Ro)-IgG positive Sjögren’s syndrome. 100% donor chimerism was detectable in the peripheral blood in all three. The specific antibodies were undetectable in donors’ and patients’ blood before alloHSCT suggesting that the antibodies had arisen from the transplanted donor immune system. Early intensive immunotherapy led to improvement of clinical symptoms and stability of the neurological disease, however, at the cost of losing the graft-versus-malignancy effect in one patient. In conclusion, we provide evidence of isolated, severe allo-immune diseases of the peripheral and central nervous system as complications of alloHSCT (“neuro-GvHD”). Interdisciplinary surveillance and thorough diagnostic work-up are needed for early diagnosis and treatment of neuro-immunologic complications after alloHSCT to improve the otherwise poor outcome.

Summary: In amyotrophic lateral sclerosis (ALS) motor neurons (MNs) undergo dying-back, where the distal axon degenerates before the soma. The hexanucleotide repeat expansion (HRE) in C9ORF72 is the most common genetic cause of ALS, but the mechanism of pathogenesis is largely unknown with both gain- and loss-of-function mechanisms being proposed. To better understand C9ORF72-ALS pathogenesis, we generated isogenic induced pluripotent stem cells. MNs with HRE in C9ORF72 showed decreased axonal trafficking compared with gene corrected MNs. However, knocking out C9ORF72 did not recapitulate these changes in MNs from healthy controls, suggesting a gain-of-function mechanism. In contrast, knocking out C9ORF72 in MNs with HRE exacerbated axonal trafficking defects and increased apoptosis as well as decreased levels of HSP70 and HSP40, and inhibition of HSPs exacerbated ALS phenotypes in MNs with HRE. Therefore, we propose that the HRE in C9ORF72 induces ALS pathogenesis via a combination of gain- and loss-of-function mechanisms. : Sterneckert and colleagues generated isogenic induced pluripotent stem cell lines and demonstrated that MNs with hexanucleotide repeat expansion (HRE) in C9ORF72 show reduced axonal trafficking, which is not recapitulated by knocking out C9ORF72 in MNs from healthy individuals. In contrast, knocking out C9ORF72 exacerbated phenotypes in MNs with HRE, suggesting that both gain- and loss-of-function mechanisms contribute to C9ORF72-ALS. Keywords: C9ORF72, induced pluripotent stem cells, amyotrophic lateral sclerosis, gene editing, disease modeling, axonal trafficking, heat shock proteins, HSP70, HSP40

Multiple system atrophy of the parkinsonian type (MSA-P) is a rare, fatal neurodegenerative disease with sporadic onset. It is still unknown if MSA-P is a primary oligodendropathy or caused by neuronal pathophysiology leading to severe, α-synuclein-associated neurodegeneration, mainly in the striatum. In this study, we generated and differentiated induced pluripotent stem cells (iPSCs) from patients with the clinical diagnosis of probable MSA-P (n = 3) and from three matched healthy controls into GABAergic striatal medium spiny neurons (MSNs). We found a significantly elevated release and neuronal distribution for α-synuclein, as well as hypoexcitability in the MSNs derived from the MSA-P patients compared to the healthy controls. These data suggest that the striatal hypoexcitable neurons of MSA-P patients contribute to a pathological α-synuclein burden which is likely to spread to neighboring cells and projection targets, facilitating disease progression.

Abstract Objective Mutations in Fused in Sarcoma (FUS or TLS) are the fourth most prevalent in Western European familial amyotrophic lateral sclerosis (ALS) populations and have been associated with causing both early and very late disease onset. FUS aggregation, DNA repair deficiency, and genomic instability are contributors to the pathophysiology of FUS‐ALS, but their clinical significance per se and their influence on the clinical variability have yet to be sufficiently investigated. The aim of this study was to analyze genotype–phenotype correlations and malignancy rates in a newly compiled FUS‐ALS cohort. Methods We cross‐sectionally reviewed FUS‐ALS patient histories in a multicenter cohort with 36 novel cases and did a meta‐analysis of published FUS‐ALS cases reporting the largest genotype–phenotype correlation of FUS‐ALS. Results The age of onset (median 39 years, range 11–80) was positively correlated with the disease duration. C‐terminal domain mutations were found in 90%. Among all, P525L and truncating/ frameshift mutations most frequently caused juvenile onset, rapid disease progression, and atypical ALS often associated with negative family history while the R521 mutation site was associated with late disease onset and pure spinal phenotype. Malignancies were found in one of 40 patients. Interpretation We report the largest genotype–phenotype correlation of FUS‐ALS, which enables a careful prediction of the clinical course in newly diagnosed patients. In this cohort, FUS‐ALS patients did not have an increased risk for malignant diseases.

Objective: Parkinson’s disease (PD) is the second most common neurodegenerative disease in the elderly. In early stages of PD, patients typically display normal brain magnet resonance imaging (MRI) in routine screening. Advanced imaging approaches are necessary to discriminate early PD patients from healthy controls. In this study, microstructural changes in relevant brain regions of early PD patients were investigated by using quantitative MRI methods.Methods: Cerebral MRI at 3T was performed on 20 PD patients in early stages and 20 age and sex matched healthy controls. Brain relative proton density, T1, T2, and T2′ relaxation times were measured in 14 regions of interest (ROIs) in each hemisphere and compared between patients and controls to estimate PD related alterations.Results: In comparison to matched healthy controls, the PD patients revealed decreased relative proton density in contralateral prefrontal subcortical area, upper and lower pons, in ipsilateral globus pallidus, and bilaterally in splenium corporis callosi, caudate nucleus, putamen, thalamus, and mesencephalon. The T1 relaxation time was increased in contralateral prefrontal subcortical area and centrum semiovale, putamen, nucleus caudatus and mesencephalon, whereas T2 relaxation time was elevated in upper pons bilaterally and in centrum semiovale ipsilaterally. T2′ relaxation time did not show significant changes.Conclusion: Early Parkinson’s disease is associated with a distinct profile of brain microstructural changes which may relate to clinical symptoms. The quantitative MR method used in this study may be useful in early diagnosis of Parkinson’s disease. Limitations of this study include a small sample size and manual selection of the ROIs. Atlas-based or statistical mapping methods would be an alternative for an objective evaluation. More studies are necessary to validate the measurement methods for clinical use in diagnostics of early Parkinson’s disease.

Somatosensory low threshold mechanoreceptors (LTMRs) sense innocuous mechanical forces, largely through specialized axon termini termed sensory nerve endings, where the mechanotransduction process initiates upon activation of mechanotransducers. In humans, a subset of sensory nerve endings is enlarged, forming bulb-like expansions, termed bulbous nerve endings. There is no in vitro human model to study these neuronal endings. Piezo2 is the main mechanotransducer found in LTMRs. Recent evidence shows that Piezo1, the other mechanotransducer considered absent in dorsal root ganglia (DRG), is expressed at low level in somatosensory neurons. We established a differentiation protocol to generate, from iPSC-derived neuronal precursor cells, human LTMR recapitulating bulbous sensory nerve endings and heterogeneous expression of Piezo1 and Piezo2. The derived neurons express LTMR-specific genes, convert mechanical stimuli into electrical signals and have specialized axon termini that morphologically resemble bulbous nerve endings. Piezo2 is concentrated within these enlarged axon termini. Some derived neurons express low level Piezo1, and a subset co-express both channels. Thus, we generated a unique, iPSCs-derived human model that can be used to investigate the physiology of bulbous sensory nerve endings, and the role of Piezo1 and 2 during mechanosensation.

The differentiation of human induced pluripotent stem cells (hiPSCs) into specific cell types for disease modeling and restorative therapies is a key research agenda and offers the possibility to obtain patient-specific cells of interest for a wide range of diseases. Basal forebrain cholinergic neurons (BFCNs) play a particular role in the pathophysiology of Alzheimer’s dementia and isolated dystonias. In this work, various directed differentiation protocols based on monolayer neural induction were tested for their effectiveness in promoting a ventral telencephalic phenotype and generating BFCN. Ventralizing factors [i.e., purmorphamine and Sonic hedgehog (SHH)] were applied at different time points, time intervals, and concentrations. In addition, caudal identity was prevented by the use of a small molecule XAV-939 that inhibits the Wnt-pathway. After patterning, gene expression profiles were analyzed by quantitative PCR (qPCR). Rostro-ventral patterning is most effective when initiated simultaneously with neural induction. The most promising combination of patterning factors was 0.5 μM of purmorphamine and 1 μM of XAV-939, which induces the highest expression of transcription factors specific for the medial ganglionic eminence, the source of GABAergic inter- and cholinergic neurons in the telencephalon. Upon maturation of cells, the immune phenotype, as well as electrophysiological properties were investigated showing the presence of marker proteins specific for BFCN (choline acetyltransferase, ISL1, p75, and NKX2.1) and GABAergic neurons. Moreover, a considerable fraction of measured cells displayed mature electrophysiological properties. Synaptic boutons containing the vesicular acetylcholine transporter (VACHT) could be observed in the vicinity of the cells. This work will help to generate basal forebrain interneurons from hiPSCs, providing a promising platform for modeling neurological diseases, such as Alzheimer’s disease or Dystonia.

The H1 haplotype of the microtubule-associated protein tau (MAPT) gene is a common genetic risk factor for some neurodegenerative diseases such as progressive supranuclear palsy, corticobasal degeneration, and Parkinson’s disease. The molecular mechanism causing the increased risk for the named diseases, however, remains unclear. In this paper, we present a valuable tool of eight small molecule neural precursor cell lines (smNPC) homozygous for the MAPT haplotypes (four H1/H1 and four H2/H2 cell lines), which can be used to identify MAPT-dependent phenotypes. The employed differentiation protocol is fast due to overexpression of NEUROGENIN-2 and therefore suitable for high-throughput approaches. A basic characterization of all human cell lines was performed, and their TAU and α-SYNUCLEIN profiles were compared during a differentiation time of 30 days. We could identify higher levels of conformationally altered TAU in cell lines carrying the H2 haplotype. Additionally, we found increased expression levels of α-SYNUCLEIN in H1/H1 cells. With this resource, we aim to fill a gap in neurodegenerative disease modeling with induced pluripotent stem cells (iPSC) for sporadic tauopathies.

DYT-THAP1 dystonia (formerly DYT6) is an adolescent-onset dystonia characterized by involuntary muscle contractions usually involving the upper body. It is caused by mutations in the gene THAP1 encoding for the transcription factor Thanatos-associated protein (THAP) domain containing apoptosis-associated protein 1 and inherited in an autosomal-dominant manner with reduced penetrance. Alterations in the development of striatal neuronal projections and synaptic function are known from transgenic mice models. To investigate pathogenetic mechanisms, human induced pluripotent stem cell (iPSC)-derived medium spiny neurons (MSNs) from two patients and one family member with reduced penetrance carrying a mutation in the gene THAP1 (c.474delA and c.38G > A) were functionally characterized in comparison to healthy controls. Calcium imaging and quantitative PCR analysis revealed significantly lower Ca2+ amplitudes upon GABA applications and a marked downregulation of the gene encoding the GABAA receptor alpha2 subunit in THAP1 MSNs indicating a decreased GABAergic transmission. Whole-cell patch-clamp recordings showed a significantly lower frequency of miniature postsynaptic currents (mPSCs), whereas the frequency of spontaneous action potentials (APs) was elevated in THAP1 MSNs suggesting that decreased synaptic activity might have resulted in enhanced generation of APs. Our molecular and functional data indicate that a reduced expression of GABAA receptor alpha2 subunit could eventually lead to limited GABAergic synaptic transmission, neuronal disinhibition, and hyperexcitability of THAP1 MSNs. These data give pathophysiological insight and may contribute to the development of novel treatment strategies for DYT-THAP1 dystonia.

A major proportion of people with Parkinson’s disease (PwP) in Germany has written an advance directive (AD). Unfortunately, these ADs are unclear for PD-specific endpoints. We previously established consensus-based recommendations for disease-specific content of an AD in PwP. However, the implementation of those recommendations and the consulting of AD creation and modification in PwP remains to be evaluated. This study aimed to investigate the practical use of PD-specific recommendations for ADs in outpatient settings. A total of 87 physicians (45 general practitioners (GPs) and 42 neurologists, 10% response rate) answered a self-constructed semiquantitative questionnaire. The participants were asked to evaluate the suggested PD-specific recommendations for ADs and the supply of palliative care in the outpatient setting. Overall, the vast majority of treating physicians agreed on the usefulness of the newly constructed PD-specific recommendations. Consultations to discuss information about PD-specific ADs were scarce with short durations. Only 24% of participating physicians implemented the PD-specific recommendations in their daily practice. GPs and neurologists agreed on the benefit of disease-specific recommendations for ADs. In future, a more general integration of these recommendations in routine care might improve specific AD creation of PwP and advanced care planning.

Progressive supranuclear palsy (PSP) is an atypical Parkinson syndrome with axial akinetic-rigid symptoms, early postural instability, and ocular motor impairments. Patients experience a rapid loss of autonomy and care dependency; thus, caregivers must assist in the activities of daily living early in the course of the disease. Caregiver burden is an extremely important factor in disease management. However, there are no specific questionnaires for assessment of caregiver burden in PSP. This study aims to validate the Parkinson’s disease caregiver burden questionnaire (PDCB) as a specific measure of caregiver burden in PSP. PSP patients were assessed by the PSP rating scale, PSP quality-of-life questionnaire (PSP-QoL), Montreal cognitive assessment test (MoCA), and geriatric depression scale (GDS-15). Caregivers filled out the short form 36-health survey, GDS-15, PDCB, and the caregiver burden inventory (CBI). 22 patient caregiver pairs completed the study. PDCB showed a highly significant correlation with the CBI (r 0.911; p

Anti-NMDA receptor encephalitis is the most common type of antibody mediated autoimmune encephalitis (AIE). Patients often develop neuropsychiatric symptoms and seizures, women are affected about four times more than men, and in about 50% the disease is associated with a neoplasia, especially teratomas of the ovary. We describe the case of a 20-year-old woman suffering from a severe therapy refractory course of anti-NMDA receptor encephalitis. Treatment included glucocorticoids, plasma exchange, intravenous immunoglobulins, rituximab, and bortezomib without clinical improvement. Due to a therapy refractive course 28 weeks after disease onset, the patient received 10 cycles of daratumumab. Therapy escalation was performed with the anti-CD38 monoclonal antibody daratumumab as off label treatment, based on the therapy of refractory myeloma and led to an improvement of her clinical status. She spent about 200 days on the intensive care unit, followed by several weeks on the intermediate care unit with close follow ups every 4–6 weeks afterward. During follow-up, the patient was able to resume everyday and self-care activities, reflected by the modified Rankin scale (mRS) and Barthel index. Because this disease is potentially life threatening and can lead to irreversible brain atrophy, development of further therapy strategies are of great importance. Our case describes a successful treatment for therapy refractory anti-NMDA receptor encephalitis using the anti-CD38 antibody daratumumab.

Little is known about the early pathogenic events by which mutant superoxide dismutase 1 (SOD1) causes amyotrophic lateral sclerosis (ALS). This lack of mechanistic understanding is a major barrier to the development and evaluation of efficient therapies. Although protein aggregation is known to be involved, it is not understood how mutant SOD1 causes degeneration of motoneurons (MNs). Previous research has relied heavily on the overexpression of mutant SOD1, but the clinical relevance of SOD1 overexpression models remains questionable. We used a human induced pluripotent stem cell (iPSC) model of spinal MNs and three different endogenous ALS-associated SOD1 mutations (D90Ahom, R115Ghet or A4Vhet) to investigate early cellular disturbances in MNs. Although enhanced misfolding and aggregation of SOD1 was induced by proteasome inhibition, it was not affected by activation of the stress granule pathway. Interestingly, we identified loss of mitochondrial, but not lysosomal, integrity as the earliest common pathological phenotype, which preceded elevated levels of insoluble, aggregated SOD1. A super-elongated mitochondrial morphology with impaired inner mitochondrial membrane potential was a unifying feature in mutant SOD1 iPSC-derived MNs. Impaired mitochondrial integrity was most prominent in mutant D90Ahom MNs, whereas both soluble disordered and detergent-resistant misfolded SOD1 was more prominent in R115Ghet and A4Vhet mutant lines. Taking advantage of patient-specific models of SOD1-ALS in vitro, our data suggest that mitochondrial dysfunction is one of the first crucial steps in the pathogenic cascade that leads to SOD1-ALS and also highlights the need for individualized medical approaches for SOD1-ALS.

Objective: We report the case of a young woman with postinfectious onset of myasthenia gravis after COVID-19 with mild respiratory symptoms and anosmia/ageusia 1 month before admission to our neurological department.Methods: Patient data were derived from medical records of Hannover Medical School, Germany. Written informed consent was obtained from the patient.Results: The 21-year-old female patient presented with subacute, vertically shifted double vision evoked by right sided partial oculomotor paresis and ptosis. About 4 weeks earlier she had suffered from mild respiratory symptoms, aching limbs and head without fever, accompanied by anosmia/ageusia. During the persistence of the latter symptoms for around 10 days the patient had already noticed “tired eyes” and fluctuating double vision. Clinical assessment including a positive test with edrophonium chloride and increased acetylcholine receptor antibodies related the ocular manifestation etiologically to myasthenia gravis. Antibodies (IgA/IgG) against SARS-CoV-2 using three different serological tests (Abbott, DiaSorin, Euroimmun) were detected in serum suggesting this specific coronavirus as previously infectious agent in our patient. The myasthenic syndrome was treated successfully with intravenous immunoglobulins and oral pyridostigmine.Conclusion: This is the first case presentation of postinfectious myasthenia gravis as neurological complication in a COVID-19 patient.

Parkinson’s disease (PD) is a progressive neurodegenerative disorder resulting in reduced health-related quality of life (HR-QoL) of people with PD (PwP) and their caregivers. Furthermore, there is an accumulating burden on caregivers of patients in advanced stages of the disease. In previous studies, motor- and non-motor-symptoms of PwP have been identified to contribute to reduced HR-QoL and an increased caregiver burden. This cross-sectional observational study aimed to study the influence of neuropsychiatric symptoms measured with the Scale for Evaluation of Neuropsychiatric Disorders in Parkinson’s Disease (SEND-PD) questionnaire on the HR-QoL of PwP, as well as the caregiver burden. Analyses revealed a significant association between SEND-PD subscale mood/apathy and reduced HR-QoL in PwP, measured by the Parkinson’s disease quality of life questionnaire (PDQ-8) (p < 0.001). Furthermore, mood/apathy was significantly correlated with caregiver burden (p = 0.001) in the multiple linear regression analysis. Hence, neuropsychiatric symptoms were found to have a profound impact on the HR-QoL of PwP, as well as on caregiver burden. Since neuropsychiatric symptoms were one of the main predictors for caregiver burden, physicians of PwP should treat these symptoms to stabilize caregiver burden, as well as HR-QoL in PwP and their caregivers.

Abnormal cytoplasmic aggregates of FUS are a hallmark of some forms of amyotrophic lateral sclerosis (ALS). Here, using neurons derived from patients with FUS-ALS, the authors demonstrate that impairment of PARP-dependent DNA damage signaling is an event that occurs upstream of neurodegeneration and cytoplasmic aggregate formation in FUS-ALS.

The SARS-CoV-2 pandemic has affected the daily life of the worldwide population since 2020. Links between the newly discovered viral infection and the pathogenesis of neurodegenerative diseases have been investigated in different studies. This review aims to summarize the literature concerning COVID-19 and Parkinson’s disease (PD) to give an overview on the interface between viral infection and neurodegeneration with regard to this current topic. We will highlight SARS-CoV-2 neurotropism, neuropathology and the suspected pathophysiological links between the infection and neurodegeneration as well as the psychosocial impact of the pandemic on patients with PD. Some evidence discussed in this review suggests that the SARS-CoV-2 pandemic might be followed by a higher incidence of neurodegenerative diseases in the future. However, the data generated so far are not sufficient to confirm that COVID-19 can trigger or accelerate neurodegenerative diseases.

Parkinson’s disease (PD) is a neurodegenerative disease which gives a person a high risk of becoming care-dependent. During disease progression, the amount of care concerning activities of daily living can increase, possibly resulting in transition of the people with Parkinson’s disease (PwP) to a care facility. However, there is a lack of knowledge concerning the factors leading to institutionalization of PwP and the consequences for them and their informal caregivers. The aim of this cross-sectional retrospective study was to investigate reasons leading to the transition into an institutional care facility, the process of decision-making and its effects on PwP symptoms and caregiver burden. Participating PwP had to be institutionalized for at most one year after transition at study inclusion. Participants completed a range of semiquantitative questionnaires as well as the caregiving tasks questionnaire. Fourteen patient–caregiver pairs were included. PwP suffered from late-stage PD symptoms with high dependence on help, experiencing several hospitalizations before transition. Analyses revealed a significant decrease in caregiver burden and depressive symptoms of the caregivers after PwP institutionalization. Factors influencing the transition were, e.g., fear of PwP health issues and concerns about caregivers’ health. This study presents new insights into the process of institutionalization and its influence on caregiver burden, including aspects for discussions of physicians with PwP and their caregivers for counselling the decision to move to institutional care.

Parkinson’s disease (PD) is a neurodegenerative disorder, which leads to reduced health-related quality of life (HR-QoL) and autonomy in advanced stages of the disease. Hence, people with PD (PwPD) are in need of help, which is often provided by informal caregivers, especially spouses. This might influence the relationship satisfaction in patients and their spousal caregivers. Additionally, previous studies have shown that a reduced relationship satisfaction may result in mental disorders and reduced physical health. The aim of this study is to identify factors influencing PwPD and their caregivers’ relationship satisfaction in a cross-sectional observational study. Analyses revealed an overall satisfying relationship, measured by the Quality of Marriage Index, in PwPD (n = 84) and their caregivers (n = 79). Relationship satisfaction in PwPD mildly decreased with reduced HR-QoL and more severe depressive symptoms. Reduced relationship satisfaction in caregivers was significantly associated with decreased HR-QoL, higher caregiver burden, more severe depressive symptoms and increased neuropsychiatric symptoms in PwPD. Further studies are needed to investigate the influence of the identified factors over time and if relationship satisfaction has a reciprocal impact on caregiver burden, HR-QoL as well as mental and physical health.

Amyotrophic lateral sclerosis (ALS) leads to selective loss of motor neurons. Using motor neurons derived from induced pluripotent stem cells from patients with ALS and FUS mutations, the authors demonstrate that axonal transport deficits that are observed in these cells can be rescued by HDAC6 inhibition.

Anti-NMDA receptor encephalitis is a rare and often therapy-responsive autoimmune disease that usually affects young adults and causes neuropsychiatric symptoms. Here, we describe a 69-year-old patient who developed anti-NMDA receptor encephalitis while being under adequate immunosuppressive therapy following liver transplantation. Although a broad spectrum of different immunotherapies was applied and anti-NMDA receptor antibody titers gradually decreased, the clinical course could not be affected positively. Autoimmune encephalitis after transplantation is only described in a few cases and not well-recognized. Our case adds further evidence for anti-NMDA receptor encephalitis as the cause of neuropsychiatric symptoms even under immunosuppressive therapy in a post-transplant setting.

Objective: To estimate alterations in neurometabolic profile of patients with early stage Parkinson's disease (PD) by using a short echo-time whole brain magnetic resonance spectroscopic imaging (wbMRSI) as possible biomarker for early diagnosis and monitoring of PD.Methods: 20 PD patients in early stage (H&Y ≤ 2) without evidence of severe other diseases and 20 age and sex matched healthy controls underwent wbMRSI. In each subject brain regional concentrations of metabolites N-acetyl-aspartate (NAA), choline (Cho), total creatine (tCr), glutamine (Gln), glutamate (Glu), and myo-inositol (mIns) were obtained in atlas-defined lobar structures including subcortical basal ganglia structures (the left and right frontal lobes, temporal lobes, parietal lobes, occipital lobes, and the cerebellum) and compared between patients and matched healthy controls. Clinical characteristics of the PD patients were correlated with spectroscopic findings.Results: In comparison to controls the PD patients revealed altered lobar metabolite levels in all brain lobes contralateral to dominantly affected body side, i.e., decreases of temporal NAA, Cho, and tCr, parietal NAA and tCr, and frontal as well as occipital NAA. The frontal NAA correlated negatively with the MDS-UPDRS II (R = 22120.585, p = 0.008), MDS-UPDRS IV (R = −0.458, p = 0.048) and total MDS-UPDRS scores (R = −0.679, p = 0.001).Conclusion: In early PD stages metabolic alterations are evident in all contralateral brain lobes demonstrating that the neurodegenerative process affects not only local areas by dopaminergic denervation, but also the functional network within different brain regions. The wbMRSI-detectable brain metabolic alterations reveal the potential to serve as biomarkers for early PD.

Background: Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection with JC-virus (JCV), a papova-virus, affecting mostly oligodendrocytes and the white matter of the central nervous system. Progressive Multifocal Leukoencephalopathy (PML) almost exclusively occurs in immunocompromised patients based on different underlying conditions of severe cellular immunodeficiency such as HIV/AIDS, secondary to neoplastic and autoimmune diseases, or during immunosuppressive therapy.Case presentation: We present the case of an otherwise healthy and immunocompetent patient without immunosuppressive therapy who was admitted with hemianopsia to the right side, sensory aphasia and changes of behavior. Magnet resonance imaging (MRI) and laboratory testing confirmed the diagnosis of PML, although functional tests did not show any evidence for cellular immunodeficiency. Extensive immunological tests did not reveal an apparent immunodeficiency. During symptomatic therapy the patient developed seizures which were assumed to be caused by a spontaneous immune reconstitution inflammatory syndrome (IRIS) demonstrated by MRI. We added a high dose of intravenous corticosteroids to the antiepileptic treatment and seizures ended shortly thereafter. However, the impairments of vision, behavior and language persisted.Conclusions: Our case report highlights that an apparently immunocompetent patient can develop PML and IRIS spontaneously. Therefore, MRI should be applied immediately whenever a rapid progression of PML symptoms occurs as treatment of IRIS with corticosteroids can result in a marked clinical improvement.

Parkinson’s disease (PD) is a progressive neurodegenerative movement disorder with an increased morbidity and mortality. People with PD (PwP) may suffer from decreased quality of life due to various motor and nonmotor symptoms. To a huge proportion, PwP have written an advance directive (AD); however, the content of these forms in regard to PD-specific complications is unclear. The aim of this study was to qualitatively and quantitatively analyze ADs of PwP in Germany. ADs of PwP were analyzed in a German sample of members of the German PD patient association. Participants completed a questionnaire about their AD and sent a copy of their AD to the study center for detailed analyses. ADs were qualitatively and quantitatively analyzed for general and PD-specific aspects and usefulness concerning treatment decisions. 82 PwP were included in the study, and in 76, an AD could be analyzed. Family members, notaries, lawyers, and general physicians mainly counseled writing of the ADs. 4 PwP consulted a neurologist to establish a specific AD for PD. In the analysis, ADs displayed a good specificity for general aspects, but they were unspecific to PD in the vast majority of cases. PwP should be encouraged to create an AD early in their disease and adapt it in the course of the disease. PD-specific aspects for an AD could be details in relation to dopaminergic therapies at the end of life, management of non-oral advanced therapies, neuropsychiatric symptoms, dementia, and swallowing disturbances.

Myoclonus-dystonia (DYT-SGCE, formerly DYT11) is characterized by alcohol-sensitive, myoclonic-like appearance of fast dystonic movements. It is caused by mutations in the SGCE gene encoding ε-sarcoglycan leading to a dysfunction of this transmembrane protein, alterations in the cerebello-thalamic pathway and impaired striatal plasticity. To elucidate underlying pathogenic mechanisms, we investigated induced pluripotent stem cell (iPSC)-derived striatal medium spiny neurons (MSNs) from two myoclonus-dystonia patients carrying a heterozygous mutation in the SGCE gene (c.298T>G and c.304C>T with protein changes W100G and R102X) in comparison to two matched healthy control lines. Calcium imaging showed significantly elevated basal intracellular Ca2+ content and lower frequency of spontaneous Ca2+ signals in SGCE MSNs. Blocking of voltage-gated Ca2+ channels by verapamil was less efficient in suppressing KCl-induced Ca2+ peaks of SGCE MSNs. Ca2+ amplitudes upon glycine and acetylcholine applications were increased in SGCE MSNs, but not after GABA or glutamate applications. Expression of voltage-gated Ca2+ channels and most ionotropic receptor subunits was not altered. SGCE MSNs showed significantly reduced GABAergic synaptic density. Whole-cell patch-clamp recordings displayed elevated amplitudes of miniature postsynaptic currents and action potentials in SGCE MSNs. Our data contribute to a better understanding of the pathophysiology and the development of novel therapeutic strategies for myoclonus-dystonia.

Parkinson’s disease (PD) is a slowly progressive neurodegenerative movement disorder that leads to impairments in activities of daily living. In addition to reducing patients’ quality of life, this disease also affects caregivers’ well-being. Until recently, caregiver burden was mainly assessed by generic questionnaires, which do not take the characteristics of the chronic disease into consideration. In the case of PD, this issue has been addressed by the introduction of the “Parkinson’s disease caregiver burden” questionnaire (PDCB). Data on longitudinal trajectories of caregiver burden are still missing in the literature. In this study, we assessed the one-year trajectory of caregiver burden by the PDCB as a disease-specific questionnaire. Further, gender-specific aspects of caregiver burden were analyzed by applying a caregiver task questionnaire. PDCB total score (n = 84 patients and caregivers) did not significantly change from baseline (30.4) to one year at follow-up (31.5). No significant difference was detected between female and male caregivers in global burden and-specific caregiver tasks. Our data showed only a mild increase of caregiver burden in the timeframe of one year. Gender-specific differences do not seem to impact-specific caregiver tasks in the presented study population.

Patients with dystonia experience unusual postures and disfigurement. The aim of the study was to examine changes in the body concept in relation to quality of life and severity of dystonia. Our cohort consisted of 20 patients with idiopathic dystonia resistant to medical therapy who were planned for pallidal deep brain stimulation. The results were compared to 25 healthy controls. The patients were assessed with Frankfurt Body Concept Scale, Short Form 36 (SF-36) Health Survey, Hamilton Depression Scale, Beck Depression Inventory, Social Phobia Inventory and Social Interaction Anxiety Scale. The disease severity was evaluated with Burke–Fahn–Marsden Dystonia Rating Scale and Toronto Western Spasmodic Torticollis Rating Scale. Patients with dystonia had a significantly impaired body concept in eight out of nine subscales in comparison to healthy controls. The differences were most pronounced for the subscales general health, body care, physical efficacy, sexuality and physical appearance (p < 0.001). Furthermore, all eight subscales of SF-36 exhibited significantly lower values in patients with dystonia compared to controls. We also found significant positive correlations between SF-36 and body concept subscales. Impairment of body concept was not associated with disease severity or levels of social anxiety symptoms. However, there was a significant association between self-rated depression and disease severity. Our patients suffered from increased depression and social anxiety symptoms except social interaction anxiety. We conclude that patients with dystonia have significant body concept impairment that interferes with quality of life in both physical and emotional domains. Future studies should focus on assessing these symptoms after adequate therapeutic management of motor symptoms.

Parkinson’s disease (PD) is the second most frequent neurodegenerative disease of people who are beyond 50 years of age. People with PD (PwP) suffer from a large variety of motor and non-motor symptoms resulting in reduced health-related quality of life (HR-QoL). In the last two decades, alexithymia was identified as an additional non-motor symptom in PD. Alexithymia is defined as a cognitive affective disturbance resulting in difficulty to identify and distinguish feelings from bodily sensations of emotional arousal. In PD, the frequency of patients suffering of alexithymia is increased compared to healthy controls. The aim of the present study was to determine the relationship of alexithymia to HR-QoL of the PwP and caregiver burden of the corresponding caregiver. This cross-sectional questionnaire-based study used disease specific questionnaires for HR-QoL and caregiver burden. In total 119 PwP and their corresponding caregivers were included in the study. HR-QoL of the PwP correlated significantly with alexithymia (p < 0.001), especially the sub-components “identifying feelings” (p < 0.001) and “difficulties describing feelings” (p = 0.001). Caregiver burden also correlated significantly with PwP alexithymia (p < 0.001). However, caregiver burden was associated with sub-components “identifying feelings” (p < 0.008) and “external oriented thinking” (p < 0.004). These data support the importance of alexithymia as a non-motor symptom in PD.

Parkinson’s disease (PD) is a neurodegenerative movement disorder with progressive impairments in activities of daily living. With disease progression, people with PD (PwP) need more help and care from their spouses or professional caregivers. Identifying factors that help caregivers to cope with their burden is needed to frame future interventions for PwP caregivers. Mindfulness and psychological flexibility might be factors contributing to resilience against the burden of giving care. In this cross-sectional questionnaire-based study, 118 PwP and their respective primary caregivers were included. Caregivers reported moderate burden and only mild depressive symptoms. Mindfulness measured by the Mindfulness Attention and Awareness scale (p 0.003) and psychological flexibility measured by Acceptance and Actions Questionnaire II (p 0.001) correlated negatively with caregiver burden. Data from this study indicate mindfulness and psychological flexibility are factors contributing to resilience against caregiver burden. Future interventions to reduce burden in PwP caregivers might be improved by the inclusion of mindfulness training programs.

Chronic granulomatous disease (CGD) is a rare genetic immunodeficiency, which is characterized by recurrent severe bacterial and fungal infections caused by a defect in phagocytic cells due to loss of superoxide production. The disease usually manifests within the first years of life. Early diagnosis allows therapeutic intervention to improve the limited life expectancy. Nevertheless, only half of the patients exceed the age of 25. Here, we present the case of a 41-year old female patient who presented with an extensive spinal cord infection and atypical pneumonia mimicking tuberculosis. The medical history with recurrent granulomatous infections and microbiological findings with multiple unusual opportunistic pathogens was the key to the diagnosis of CGD, which is exceptionally rare first diagnosed in patients in the fifth decade of life. The late diagnosis in this case was likely due to the lack of knowledge of the disease by the treating teams before but not because the patient did not have typical CGD infections along her life. The extensive progressive developing granulomas in our patient with fatal outcome raise the question of early immunosuppressive therapy in addition to anti-infectious treatment. We recommend appropriate CGD diagnostics in adult patients with unclear granulomatous diseases of the nervous system.

BackgroundParkinson’s disease (PD) is the second most frequent neurodegenerative disease of the elderly. Patients suffer from various motor and non-motor symptoms leading to reduced health-related quality of life (HRQOL) and an increased mortality. Their loss of autonomy due to dementia, psychosis, depression, motor impairments, falls, and swallowing deficits defines a phase when palliative care interventions might help to sustain or even improve quality of life.ObjectiveThe aim of this study was to investigate the current status of palliative care implementation and quality of life in a local cohort of advanced PD patients in order to frame and improve future care.Methods76 geriatric patients with advanced idiopathic PD meeting the inclusion criteria for palliative care interventions were clinically evaluated by neurological examination using Movement Disorders Society Unified Parkinson’s Disease Rating Scale, Barthel Index, Montreal Cognitive Assessment Test, and a structured interview concerning palliative care implementation.ResultsHRQOL is severely reduced in our cohort of geriatric advanced PD patients. We found motor deficits, impairment of activities of daily living, depression, and cognitive decline as most relevant factors determining decreased HRQOL. Only 2.6% of our patients reported present implementation of palliative care. By contrast, 72% of the patients indicated an unmet need for palliative care.ConclusionQuality of life is dramatically affected in advanced PD patients. However, we found palliative care to be implemented extremely rare in their treatment concept. Therefore, geriatric patients suffering from advanced PD should be enrolled for palliative care to provide adequate and holistic treatment which may improve or sustain their quality of life.

Abnormalities in the somatosensory system are increasingly being recognized in patients with dystonia. The aim of this study was to investigate whether sensory abnormalities are confined to the dystonic body segments or whether there is a wider involvement in patients with idiopathic dystonia. For this purpose, we recruited 20 patients, 8 had generalized, 5 had segmental dystonia with upper extremity involvement, and 7 had cervical dystonia. In total, there were 13 patients with upper extremity involvement. We used Quantitative Sensory Testing (QST) at the back of the hand in all patients and at the shoulder in patients with cervical dystonia. The main finding on the hand QST was impaired cold detection threshold (CDT), dynamic mechanical allodynia (DMA), and thermal sensory limen (TSL). The alterations were present on both hands, but more pronounced on the side more affected with dystonia. Patients with cervical dystonia showed a reduced CDT and hot detection threshold (HDT), enhanced TSL and DMA at the back of the hand, whereas the shoulder QST only revealed increased cold pain threshold and DMA. In summary, QST clearly shows distinct sensory abnormalities in patients with idiopathic dystonia, which may also manifest in body regions without evident dystonia. Further studies with larger groups of dystonia patients are needed to prove the consistency of these findings.

Direct reprogramming from somatic to neural cell types has become an alternative to induced pluripotent stem cells. Most protocols employ viral expression systems, posing the risk of random genomic integration. Recent developments led to plasmid-based protocols, lowering this risk. However, these protocols either relied on continuous presence of a variety of small molecules or were only able to reprogram murine cells. We therefore established a reprogramming protocol based on vectors containing the Epstein-Barr virus (EBV)-derived oriP/EBNA1 as well as the defined expression factors Oct3/4, Sox2, Klf4, L-myc, Lin28, and a small hairpin directed against p53. We employed a defined neural medium in combination with the neurotrophins bFGF, EGF and FGF4 for cultivation without the addition of small molecules. After reprogramming, cells demonstrated a temporary increase in the expression of endogenous Oct3/4. We obtained induced neural stem cells (iNSC) 30 days after transfection. In contrast to previous results, plasmid vectors as well as a residual expression of reprogramming factors remained detectable in all cell lines. Cells showed a robust differentiation into neuronal (72%) and glial cells (9% astrocytes, 6% oligodendrocytes). Despite the temporary increase of pluripotency-associated Oct3/4 expression during reprogramming, we did not detect pluripotent stem cells or non-neural cells in culture (except occasional residual fibroblasts). Neurons showed electrical activity and functional glutamatergic synapses. Our results demonstrate that reprogramming adult human fibroblasts to iNSC by plasmid vectors and basic neural medium without small molecules is possible and feasible. However, a full set of pluripotency-associated transcription factors may indeed result in the acquisition of a transient (at least partial) pluripotent intermediate during reprogramming. In contrast to previous reports, the EBV-based plasmid system remained present and active inside the cells at all time points.

Human induced pluripotent stem cells (hiPSCs) are promising sources for regenerative therapies like the replacement of dopaminergic neurons in Parkinson's disease. They offer an unlimited cell source that can be standardized and optimized to produce applicable cell populations to gain maximal functional recovery. In the present study, human cord blood-derived iPSCs (hCBiPSCs) were differentiated into dopaminergic neurons utilizing two different in vitro protocols for neural induction: (protocol I) by fibroblast growth factor (FGF-2) signaling, (protocol II) by bone morphogenetic protein (BMP)/transforming growth factor (TGF-β) inhibition. After maturation, in vitro increased numbers of tyrosine hydroxylase (TH)-positive neurons (7.4% of total cells) were observed by protocol II compared to 3.5% in protocol I. Furthermore, 3 weeks after transplantation in hemiparkinsonian rats in vivo, a reduced number of undifferentiated proliferating cells was achieved with protocol II. In contrast, proliferation still occurred in protocol I-derived grafts, resulting in tumor-like growth in two out of four animals 3 weeks after transplantation. Protocol II, however, did not increase the number of TH + cells in the striatal grafts of hemiparkinsonian rats. In conclusion, BMP/TGF-β inhibition was more effective than FGF-2 signaling with regard to dopaminergic induction of hCBiPSCs in vitro and prevented graft overgrowth in vivo.

The purpose of this study was to generate quadruple fluorescent protein (QFP) transgenic mice as a source for QFP-expressing neural stem and progenitor cells (NSCs/NPCs) that could be utilized as a tool for transplantation research. When undifferentiated, these NSCs only express cyan fluorescent protein (CFP); however, upon neuronal differentiation, the cells express yellow fluorescent protein (YFP). During astrocytic differentiation, the cells express green fluorescent protein (GFP), and during oligodendrocytic differentiation, the cells express red fluorescent protein (DsRed). Using immunocytochemistry, immunoblotting, flow cytometry and electrophysiology, quadruple transgenic NPCs (Q-NPCs) and GFP-sorted NPCs were comprehensively characterized in vitro. Overall, the various transgenes did not significantly affect proliferation and differentiation of transgenic NPCs in comparison to wild-type NPCs. In contrast to a strong CFP and GFP expression in vitro, NPCs did not express YFP and dsRed either during proliferation or after differentiation in vitro. GFP-positive sorted NPCs, expressing GFP under the control of the human GFAP promoter, demonstrated a significant improvement in astroglial differentiation in comparison to GFP-negative sorted NPCs. In contrast to non-sorted and GFP-positive sorted NPCs, GFP-negative sorted NPCs demonstrated a high proportion of neuronal differentiation and proved to be functional in vitro. At 6 weeks after the intracerebroventricular transplantation of Q-NPCs into neonatal wild-type mice, CFP/DCX (doublecortin) double-positive transplanted cells were observed. The Q-NPCs did not express any other fluorescent proteins and did not mature into neuronal or glial cells. Although this model failed to visualize NPC differentiation in vivo, we determined that activation of the NPC glial fibrillary acid protein (GFAP) promoter, as indicated by GFP expression, can be used to separate neuronal and glial progenitors as a valuable tool for transplantation studies.

BACKGROUND: RGS9-deficient mice show drug-induced dyskinesia but normal locomotor activity under unchallenged conditions. RESULTS: Genes related to Ca2+ signaling and their functions were regulated in RGS9-deficient mice. CONCLUSION: Changes in Ca2+ signaling that compensate for RGS9 loss-of-function can explain the normal locomotor activity in RGS9-deficient mice under unchallenged conditions. SIGNIFICANCE: Identified signaling components may represent novel targets in antidyskinetic therapy. The long splice variant of the regulator of G-protein signaling 9 (RGS9-2) is enriched in striatal medium spiny neurons and dampens dopamine D2 receptor signaling. Lack of RGS9-2 can promote while its overexpression prevents drug-induced dyskinesia. Other animal models of drug-induced dyskinesia rather pointed towards overactivity of dopamine receptor-mediated signaling. To evaluate changes in signaling pathways mRNA expression levels were determined and compared in wild-type and RGS9-deficient mice. Unexpectedly, expression levels of dopamine receptors were unchanged in RGS9-deficient mice, while several genes related to Ca2+ signaling and long-term depression were differentially expressed when compared to wild type animals. Detailed investigations at the protein level revealed hyperphosphorylation of DARPP32 at Thr34 and of ERK1/2 in striata of RGS9-deficient mice. Whole cell patch clamp recordings showed that spontaneous synaptic events are increased (frequency and size) in RGS9-deficient mice while long-term depression is reduced in acute brain slices. These changes are compatible with a Ca2+-induced potentiation of dopamine receptor signaling which may contribute to the drug-induced dyskinesia in RGS9-deficient mice.

BACKGROUND: Human fetal midbrain-derived neural progenitor cells (NPCs) may deliver a tissue source for drug screening and regenerative cell therapy to treat Parkinson's disease. While glutamate and GABA(A) receptors play an important role in neurogenesis, the involvement of glycine receptors during human neurogenesis and dopaminergic differentiation as well as their molecular and functional characteristics in NPCs are largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigated NPCs in respect to their glycine receptor function and subunit expression using electrophysiology, calcium imaging, immunocytochemistry, and quantitative real-time PCR. Whole-cell recordings demonstrate the ability of NPCs to express functional strychnine-sensitive glycine receptors after differentiation for 3 weeks in vitro. Pharmacological and molecular analyses indicate a predominance of glycine receptor heteromers containing α2β subunits. Intracellular calcium measurements of differentiated NPCs suggest that glycine evokes depolarisations mediated by strychnine-sensitive glycine receptors and not by D-serine-sensitive excitatory glycine receptors. Culturing NPCs with additional glycine, the glycine-receptor antagonist strychnine, or the Na(+)-K(+)-Cl(-) co-transporter 1 (NKCC1)-inhibitor bumetanide did not significantly influence cell proliferation and differentiation in vitro. CONCLUSIONS/SIGNIFICANCE: These data indicate that NPCs derived from human fetal midbrain tissue acquire essential glycine receptor properties during neuronal maturation. However, glycine receptors seem to have a limited functional impact on neurogenesis and dopaminergic differentiation of NPCs in vitro.

BackgroundVoltage-gated potassium (K(v)) channels are among the earliest ion channels to appear during brain development, suggesting a functional requirement for progenitor cell proliferation and/or differentiation. We tested this hypothesis, using human neural progenitor cells (hNPCs) as a model system.Methodology/principal findingsIn proliferating hNPCs a broad spectrum of K(v) channel subtypes was identified using quantitative real-time PCR with a predominant expression of the A-type channel K(v)4.2. In whole-cell patch-clamp recordings K(v) currents were separated into a large transient component characteristic for fast-inactivating A-type potassium channels (I(A)) and a small, sustained component produced by delayed-rectifying channels (I(K)). During differentiation the expression of I(A) as well as A-type channel transcripts dramatically decreased, while I(K) producing delayed-rectifiers were upregulated. Both K(v) currents were differentially inhibited by selective neurotoxins like phrixotoxin-1 and alpha-dendrotoxin as well as by antagonists like 4-aminopyridine, ammoniumchloride, tetraethylammonium chloride and quinidine. In viability and proliferation assays chronic inhibition of the A-type currents severely disturbed the cell cycle and precluded proper hNPC proliferation, while the blockade of delayed-rectifiers by alpha-dendrotoxin increased proliferation.Conclusions/significanceThese findings suggest that A-type potassium currents are essential for proper proliferation of immature multipotent hNPCs.