Lars Tönges

Fasudil attenuates aggregation of α-synuclein in models of Parkinson’s disease

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder, yet disease-modifying treatments do not currently exist. Rho-associated protein kinase (ROCK) was recently described as a novel neuroprotective target in PD. Since alpha-synuclein (α-Syn) aggregation is a major hallmark in the pathogenesis of PD, we aimed to evaluate the anti-aggregative potential of pharmacological ROCK inhibition using the isoquinoline derivative Fasudil, a small molecule inhibitor already approved for clinical use in humans. Fasudil treatment significantly reduced α-Syn aggregation in vitro in a H4 cell culture model as well as in a cell-free assay. Nuclear magnetic resonance spectroscopy analysis revealed a direct binding of Fasudil to tyrosine residues Y133 and Y136 in the C-terminal region of α-Syn. Importantly, this binding was shown to be biologically relevant using site-directed mutagenesis of these residues in the cell culture model. Furthermore, we evaluated the impact of long-term Fasudil treatment on α-Syn pathology in vivo in a transgenic mouse model overexpressing human α-Syn bearing the A53T mutation (α-SynA53T mice). Fasudil treatment improved motor and cognitive functions in α-SynA53T mice as determined by CatwalkTM gait analysis and novel object recognition (NOR), without apparent side effects. Finally, immunohistochemical analysis revealed a significant reduction of α-Syn pathology in the midbrain of α-SynA53T mice after Fasudil treatment. Our results demonstrate that Fasudil, next to its effects mediated by ROCK-inhibition, directly interacts with α-Syn and attenuates α-Syn pathology. This underscores the translational potential of Fasudil as a disease-modifying drug for the treatment of PD and other synucleinopathies.

Classification of advanced stages of Parkinson’s disease: translation into stratified treatments

Advanced stages of Parkinson’s disease (advPD) still impose a challenge in terms of classification and related stage-adapted treatment recommendations. Previous concepts that define advPD by certain milestones of motor disability apparently fall short in addressing the increasingly recognized complexity of motor and non-motor symptoms and do not allow to account for the clinical heterogeneity that require more personalized approaches. Therefore, deep phenotyping approaches are required to characterize the broad-scaled, continuous and multidimensional spectrum of disease-related motor and non-motor symptoms and their progression under real-life conditions. This will also facilitate the reasoning for clinical care and therapeutic decisions, as neurologists currently have to refer to clinical trials that provide guidance on a group level; however, this does not always account for the individual needs of patients. Here, we provide an overview on different classifications for advPD that translate into critical phenotypic patterns requiring the differential therapeutic adjustments. New concepts refer to precision medicine approaches also in PD and first studies on genetic stratification for therapeutic outcomes provide a potential for more objective treatment recommendations. We define novel treatment targets that align with this concept and make use of emerging device-based assessments of real-life information on PD symptoms. As these approaches require empowerment of patients and integration into treatment decisions, we present communication strategies and decision support based on new technologies to adjust treatment of advPD according to patient demands and safety.

Deferiprone Rescues Behavioral Deficits Induced by Mild Iron Exposure in a Mouse Model of Alpha-Synuclein Aggregation

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder, and its causes remain unknown. A major hallmark of the disease is the increasing presence of aggregated alpha-synuclein (aSyn). Furthermore, there is a solid consensus on iron (Fe) accumulation in several regions of PD brains during disease progression. In our study, we focused on the interaction of Fe and aggregating aSyn in vivo in a transgenic mouse model overexpressing human aSyn bearing the A53T mutation (prnp.aSyn.A53T). We utilized a neonatal iron-feeding model to exacerbate the motor phenotype of the transgenic mouse model. Beginning from day 100, mice were treated with deferiprone (DFP), a ferric chelator that is able to cross the blood–brain barrier and is currently used in clinics as treatment for hemosiderosis. Our paradigm resulted in an impairment of the learning abilities in the rotarod task and the novel object recognition test. DFP treatment significantly improved the performance in both tasks. Although this was not accompanied by alterations in aSyn aggregation, our results support DFP as possible therapeutic option in PD.

Rho Kinase Inhibition with Fasudil in the SOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis—Symptomatic Treatment Potential after Disease Onset

Despite an improved understanding of the genetic background and the pathomechanisms of amyotrophic lateral sclerosis (ALS) no novel disease-modifying therapies have been successfully implemented in clinical routine. Riluzole still remains the only clinically approved substance in human ALS treatment with limited efficacy. We have previously identified pharmacological rho kinase (ROCK) inhibitors as orally applicable substances in SOD1.G93A transgenic ALS mice (SOD1G93A), which are able to extend survival time and improve motor function after presymptomatic treatment. Here, we have evaluated the therapeutic effect of the orally administered ROCK inhibitor Fasudil starting at a symptomatic disease stage, more realistically reflecting the clinical situation. Oral Fasudil treatment was initiated at a symptomatic stage at 80 days of life (d80) with 30 or 100 mg/kg body weight in both female and male mice. While baseline neurological scoring and survival were not influenced, Fasudil significantly improved motor behavior in male mice. Spinal cord pathology of motoneurons (MN) and infiltrating microglial cells (MG) at disease end-stage were not significantly modified. Although treatment after symptom onset was less potent than treatment in asymptomatic animals, our study shows the therapeutic benefits of this well-tolerated substance, which is already in clinical use for other indications.

Modulation of Microglial Activity by Rho-Kinase (ROCK) Inhibition as Therapeutic Strategy in Parkinson’s Disease and Amyotrophic Lateral Sclerosis

Neurodegenerative diseases are characterized by the progressive degeneration of neurons in the central and peripheral nervous system (CNS, PNS), resulting in a reduced innervation of target structures and a loss of function. A shared characteristic of many neurodegenerative diseases is the infiltration of microglial cells into affected brain regions. During early disease stages microglial cells often display a rather neuroprotective phenotype, but switch to a more pro-inflammatory neurotoxic phenotype in later stages of the disease, contributing to the neurodegeneration. Activation of the Rho kinase (ROCK) pathway appears to be instrumental for the modulation of the microglial phenotype: increased ROCK activity in microglia mediates mechanisms of the inflammatory response and is associated with improved motility, increased production of reactive oxygen species (ROS) and release of inflammatory cytokines. Recently, several studies suggested inhibition of ROCK signaling as a promising treatment option for neurodegenerative diseases. In this review article, we discuss the contribution of microglial activity and phenotype switch to the pathophysiology of Parkinson’s disease (PD) and Amyotrophic lateral sclerosis (ALS), two devastating neurodegenerative diseases without disease-modifying treatment options. Furthermore, we describe how ROCK inhibition can influence the microglial phenotype in disease models and explore ROCK inhibition as a future treatment option for PD and ALS.

Elemental fingerprint as a cerebrospinal fluid biomarker for the diagnosis of Parkinson's disease

The diagnosis of Parkinsons disease (PD) still lacks objective diagnostic markers independent of clinical criteria. Cerebrospinal fluid (CSF) samples from 36 PD and 42 age‐matched control patients were subjected to inductively coupled plasma‐sector field mass spectrometry and a total of 28 different elements were quantified. Different machine learning algorithms were applied to the dataset to identify a discriminating set of elements yielding a novel biomarker signature. Using 19 stably detected elements, the extreme gradient tree boosting model showed the best performance in the discrimination of PD and control patients with high specificity and sensitivity (78.6% and 83.3%, respectively), re‐classifying the training data to 100%. The 10 times 10‐fold cross‐validation yielded a good area under the receiver operating characteristic curve of 0.83. Arsenic, magnesium, and selenium all showed significantly higher mean CSF levels in the PD group compared to the control group (p = 0.01, p = 0.04, and p = 0.03). Reducing the number of elements to a discriminating minimum, we identified an elemental cluster (Se, Fe, As, Ni, Mg, Sr), which most importantly contributed to the sample discrimination. Selenium was identified as the element with the highest impact within this cluster directly followed by iron. After prospective validation, this elemental fingerprint in the CSF could have the potential to be used as independent biomarker for the diagnosis of PD. Next to their value as a biomarker, these data also argue for a prominent role of these highly discriminating six elements in the pathogenesis of PD.

ROCK inhibition in models of neurodegeneration and its potential for clinical translation

Neurodegenerative disorders like Parkinsons disease, Alzheimers disease, or amyotrophic lateral sclerosis are affecting a rapidly increasing population worldwide. While common pathomechanisms such as protein aggregation, axonal degeneration, dysfunction of protein clearing and an altered immune response have been characterized, no disease-modifying therapies have been developed so far. Interestingly, a significant involvement of the Rho kinase (ROCK) signaling pathway has been described in all of these mechanisms making it a promising target for new therapeutic approaches. In this article, we first review current knowledge of the involvement of ROCK in neurodegenerative disorders and the utility of its inhibition as a disease-modifying therapy in different neurodegenerative disorders. After a detailed description of the biochemical characteristics of ROCK and its molecular interactors, differences of ROCK-expression under physiological and pathological conditions are compared. Next, different pharmacological and molecular-genetic strategies to inhibit ROCK-function are discussed, focusing on pharmacological ROCK-inhibitors. The role of the ROCK-pathway in cellular processes that are central in neurodegenerative disorders pathology like axonal degeneration, autophagy, synaptic and glial function is explained in detail. Finally, all available data on ROCK-inhibition in different animal models of neurodegenerative disorders is reviewed and first approaches for translation into human patients are discussed. Taken together, there is now extensive evidence from preclinical studies in several neurodegenerative disorders that characterize ROCK as a promising drug target for further translational research in neurodegenerative disorders.

Coronal Transcranial Sonography and M-Mode Tremor Frequency Determination in Parkinson's Disease and Essential Tremor: Coronal TCS and MTFD in PD and ET

The axial mesencephalic transcranial sonography plane is an established and sensitive diagnostic tool for the differentiation of Parkinsons disease and essential tremor. However, the substantia nigra can also be depicted in a second coronal examination plane, whose diagnostic value has not yet been evaluated. Furthermore, the M‐mode tremor frequency determination represents another sonographic tool, which might yield additional diagnostic value.

Charakteristika und Dynamik der stationären Behandlung von Parkinson-Patienten in Deutschland

BACKGROUNDnParkinsons disease is the most common neurodegenerative movement disorder and the fastest-growing neurological disease in the world. The diagnostic spectrum, demographic characteristics, comorbidities and case number developments of inpatient treatment in Germany with resulting implications for patient care have so far been insufficiently investigated.nnnMETHODSnData from the diagnosis-related groups (DRG) statistics were analyzed in patients with a main and secondary diagnosis of primary Parkinsons syndrome (PS), secondary PS or other degenerative disease of the basal ganglia. For the reporting years 2010-2015, the dataset comprised 1,520,366 patient cases from 413 districts/independent cities throughout Germany.nnnRESULTSnIn 2015, mostly patients with moderate and severe primary PS were hospitalized (64.7%) often exhibiting motor fluctuations as well as marked medical and psychiatric comorbidities. Vascular parkinsonism was the most frequent secondary PS (36.6%) and progressive supranuclear palsy was the leading diagnosis in the other disorders of the basal ganglia (51.9%). Primary PS as axa0secondary diagnosis was found in many internal medicine hospitalizations. The inpatient case numbers for primary PS increased significantly from the years 2010 to 2015 and rural regions were particularly affected.nnnCONCLUSIONnThe number of inpatient cases of Parkinsons disease is greatly increasing in Germany and mainly affects patients with severe motor complications and secondary parkinsonian syndromes. Particularly in rural areas, there is axa0risk of overburdening the treatment infrastructure, so that both outpatient and inpatient sectors must be strengthened. Axa0limitation of the study is the analysis of only DRG coded data, whose quality could be improved in subsequent examinations by comparison with the current diagnostic criteria of the specialist societies.ZusammenfassungHintergrundDie Parkinson-Erkrankung ist die häufigste neurodegenerative Bewegungsstörung und weltweit am schnellsten zunehmende neurologische Erkrankung. Das Diagnosespektrum, demographische Charakteristika, Komorbiditäten und Fallzahlentwicklungen stationärer Behandlungen in Deutschland mit resultierenden Implikationen für die Patientenversorgung sind bisher nur unzureichend untersucht.UntersuchungsmethodeDaten der DRG-Statistik wurden hinsichtlich der Patientenfälle mit Haupt- und Nebendiagnose eines primären Parkinson-Syndroms (PS), sekundären PS oder einer sonstigen degenerativen Krankheit der Basalganglien analysiert. Der Datensatz umfasste für die Berichtsjahre 2010 bis 2015 deutschlandweit 1.520.366 Patientenfälle aus 413 Kreisen/kreisfreien Städten.ErgebnisseVon Patienten mit primärem PS wurden im Jahr 2015 vorwiegend solche mit mäßiger und schwerer Beeinträchtigung stationär behandelt (64,7u202f%), die häufig Wirkungsfluktuationen sowie relevante internistische und psychiatrische Begleiterkrankungen aufweisen. Bei den sekundären PS dominierte das vaskuläre PS (36,6u202f%) und bei den sonstigen Erkrankungen der Basalganglien die progressive supranukleäre Ophthalmoplegie (51,9u202f%) als atypische Parkinson-Erkrankung. Zahlreiche internistische Aufnahmen erheben die Nebendiagnose primäres PS. In den Jahren 2010 bis 2015 steigen die Fallzahlen für das primäre PS deutlich an und insbesondere ländliche Regionen sind betroffen.SchlussfolgerungDie Fallzahlen für die stationäre Versorgung von Patienten mit Parkinson-Erkrankungen nehmen in Deutschland stark zu und betreffen vor allem Patienten mit schweren motorischen Komplikationen und sekundären PS. Insbesondere in ländlichen Regionen droht eine Überforderung der Behandlungsinfrastruktur, sodass der ambulante und stationäre Sektor gestärkt werden müssen. Eine Limitation der Studie besteht in der Analyse reiner DRG-Diagnosedaten, deren Qualität in nachfolgenden Untersuchungen durch Abgleich mit den Diagnosekriterien der Fachgesellschaften verbessert werden kann.AbstractBackgroundParkinson’s disease is the most common neurodegenerative movement disorder and the fastest-growing neurological disease in the world. The diagnostic spectrum, demographic characteristics, comorbidities and case number developments of inpatient treatment in Germany with resulting implications for patient care have so far been insufficiently investigated.MethodsData from the diagnosis-related groups (DRG) statistics were analyzed in patients with a main and secondary diagnosis of primary Parkinson’s syndrome (PS), secondary PS or other degenerative disease of the basal ganglia. For the reporting years 2010–2015, the dataset comprised 1,520,366 patient cases from 413 districts/independent cities throughout Germany.ResultsIn 2015, mostly patients with moderate and severe primary PS were hospitalized (64.7%) often exhibiting motor fluctuations as well as marked medical and psychiatric comorbidities. Vascular parkinsonism was the most frequent secondary PS (36.6%) and progressive supranuclear palsy was the leading diagnosis in the other disorders of the basal ganglia (51.9%). Primary PS as axa0secondary diagnosis was found in many internal medicine hospitalizations. The inpatient case numbers for primary PS increased significantly from the years 2010 to 2015 and rural regions were particularly affected.ConclusionThe number of inpatient cases of Parkinson’s disease is greatly increasing in Germany and mainly affects patients with severe motor complications and secondary parkinsonian syndromes. Particularly in rural areas, there is axa0risk of overburdening the treatment infrastructure, so that both outpatient and inpatient sectors must be strengthened. Axa0limitation of the study is the analysis of only DRG coded data, whose quality could be improved in subsequent examinations by comparison with the current diagnostic criteria of the specialist societies.

miR-182-5p and miR-183-5p Act as GDNF Mimics in Dopaminergic Midbrain Neurons

Parkinson’s disease (PD) is the second-most-frequent neurodegenerative disorder worldwide. One major hallmark of PD is the degeneration of dopaminergic (DA) neurons in the substantia nigra. Glial cell line-derived neurotrophic factor (GDNF) potently increases DA neuron survival in models of PD; however, the underlying mechanisms are incompletely understood. MicroRNAs (miRNAs) are small, non-coding RNAs that are important for post-transcriptional regulation of gene expression. Using small RNA sequencing, we show that GDNF specifically increases the expression of miR-182-5p and miR-183-5p in primary midbrain neurons (PMNs). Transfection of synthetic miR-182-5p and miR-183-5p mimics leads to increased neurite outgrowth and mediates neuroprotection of DA neurons in vitro and in vivo, mimicking GDNF effects. This is accompanied by decreased expression of FOXO3 and FOXO1 transcription factors and increased PI3K-Akt signaling. Inhibition of endogenous miR-182-5p or miR-183-5p in GDNF-treated PMNs attenuated the pro-DA effects of GDNF. These findings unveil an unknown miR-mediated mechanism of GDNF action and suggest that targeting miRNAs is a new therapeutic avenue to PD phenotypes.