Influence of Janus Kinase Inhibitors on the Neuronal Activity as a Proof-of-Concept Model for Itch.

BACKGROUND: Itching is considered to be a subjective symptom of the activation of neurosensory structures by different signal molecules and trigger factors. The signaling cascades responsible for it are closely linked to inflammatory processes. This explains why itching also occurs in many inflammatory diseases. One of these signaling cascades is mediated by Janus kinases (JAKs). Recently, it could be shown on a molecular level that Janus kinase 1 (JAK1) directly activates frontal cortex neurons and thus can cause chronic itching. OBJECTIVES: This study deals with the influence of different JAK inhibitors (JAKi) on the activity of chip-based neural networks of cultured frontal cortex neurons by investigating neurophysiological activity parameters. This in vitro model provides information on dose-dependent effects of model substances with different specificity regarding the inhibition of different JAKs. METHODS: Tofacitinib (pan-JAKi), baricitinib (JAK1/2i), and upadacitinib (JAK1i) in a concentration range from 10 nmol/L to 50 µmol/L were tested in a microelectrode array neurochip culture system. RESULTS: The results show that the inhibition of the neuronal activity of frontal cortex neurons increases with JAK1 selectivity and is dependent on concentration. CONCLUSION: These observations are supported by data from clinical studies in atopic dermatitis and psoriasis. The clinical relevance of these results must be proven by further clinical studies with subjective and objective parameters for itching.

Ginkgo biloba L. (Ginkgoaceae) Leaf Extract Medications From Different Providers Exhibit Differential Functional Effects on Mouse Frontal Cortex Neuronal Networks.

Background: Details of the extraction and purification procedure can have a profound impact on the composition of plant-derived extracts, and thus on their efficacy and safety. So far, studies with head-to-head comparison of the pharmacology of Ginkgo extracts rendered by different procedures have been rare. Objective: The objective of this study was to explore whether Ginkgo biloba L. (Ginkgoaceae) leaf extract medications of various sources protect against amyloid beta toxicity on primary mouse cortex neurons growing on microelectrode arrays, and whether the effects differ between different Ginkgo extracts. Design: Our brain-on-chip platform integrates microelectrode array data recorded on neuronal tissue cultures from embryonic mouse cortex. Amyloid beta 42 (Aß42) and various Ginkgo extract preparations were added to the networks in vitro before evaluation of electrophysiological parameters by multi-parametric analysis. A Multi-variate data analysis, called Effect Score, was designed to compare effects between different products. Results: The results show that Ginkgo extracts protected against Aß42-induced electrophysiological alterations. Different Ginkgo extracts exhibited different effects. Of note, the reference Ginkgo biloba L. (Ginkgoaceae) leaf medication Tebonin had the most pronounced rescuing effect. Conclusion: Here, we show for the first time a side-by-side analysis of a large number of Ginkgo medications in a relevant in vitro system modeling early functional effects induced by amyloid beta peptides on neuronal transmission and connectivity. Ginkgo biloba L. (Ginkgoaceae) leaf extract from different manufactures exhibit differential functional effects in this neural network model. This in-depth analysis of functional phenotypes of neurons cultured on MEAs chips allows identifying optimal plant extract formulations protecting against toxin-induced functional effects in vitro.

Improvement of impaired electrical activity in NPC1 mutant cortical neurons upon DHPG stimulation detected by micro-electrode array.

Niemann-Pick Type C1 (NPC1) disease is an autosomal recessive neurodegenerative disease characterized by an excessive accumulation of unesterified cholesterol in late endosomes/lysosomes. Patients with NPC1 disease show a series of symptoms in neuropathology, including a gradually increased loss of motor control and seizures. However, mechanism of the neurological manifestations in NPC1 disease is not fully understood yet. In this study, we utilized the micro-electrode array (MEA) to analyze the spontaneous extracellular electrical activity in cultivated cortical neurons of the NPC1 mutant (NPC1-/-) mouse. Our results show a decrease of the spontaneous electrical activity in NPC1-/- neuronal network when compared to wild type neurons, as indicated by the decreased spike rate, burst rate, event rate, and the increased burst period and event period. Application of 3,5-dihydroxyphenylglycine (DHPG), a specific agonist of group I metabotropic glutamate receptors, improved the electrical activity of the NPC1-/- neuronal network, suggesting that DHPG can be used as a potential therapeutic strategy for recovery of the electrical activity in NPC1 disease.

Enhancement of Cortical Network Activity in vitro and Promotion of GABAergic Neurogenesis by Stimulation with an Electromagnetic Field with a 150 MHz Carrier Wave Pulsed with an Alternating 10 and 16 Hz Modulation.

In recent years, various stimuli were identified capable of enhancing neurogenesis, a process which is dysfunctional in the senescent brain and in neurodegenerative and certain neuropsychiatric diseases. Applications of electromagnetic fields to brain tissue have been shown to affect cellular properties and their importance for therapies in medicine is recognized. In this study, differentiating murine cortical networks on multiwell microelectrode arrays were repeatedly exposed to an extremely low-electromagnetic field (ELEMF) with alternating 10 and 16 Hz frequencies piggy backed onto a 150 MHz carrier frequency. The ELEMF exposure stimulated the electrical network activity and intensified the structure of bursts. Further, the exposure to electromagnetic fields within the first 28 days in vitro of the differentiation of the network activity induced also reorganization within the burst structure. This effect was already most pronounced at 14 days in vitro after 10 days of exposure. Overall, the development of cortical activity under these conditions was accelerated. These functional electrophysiological changes were accompanied by morphological ones. The percentage of neurons in the neuron glia co-culture was increased without affecting the total number of cells, indicating an enhancement of neurogenesis. The ELEMF exposure selectively promoted the proliferation of a particular population of neurons, evidenced by the increased proportion of GABAergic neurons. The results support the initial hypothesis that this kind of ELEMF stimulation could be a treatment option for specific indications with promising potential for CNS applications, especially for degenerative diseases, such as Alzheimer's disease and other dementias.

Evaluation of drug-induced neurotoxicity based on metabolomics, proteomics and electrical activity measurements in complementary CNS in vitro models.

The present study was performed in an attempt to develop an in vitro integrated testing strategy (ITS) to evaluate drug-induced neurotoxicity. A number of endpoints were analyzed using two complementary brain cell culture models and an in vitro blood-brain barrier (BBB) model after single and repeated exposure treatments with selected drugs that covered the major biological, pharmacological and neuro-toxicological responses. Furthermore, four drugs (diazepam, cyclosporine A, chlorpromazine and amiodarone) were tested more in depth as representatives of different classes of neurotoxicants, inducing toxicity through different pathways of toxicity. The developed in vitro BBB model allowed detection of toxic effects at the level of BBB and evaluation of drug transport through the barrier for predicting free brain concentrations of the studied drugs. The measurement of neuronal electrical activity was found to be a sensitive tool to predict the neuroactivity and neurotoxicity of drugs after acute exposure. The histotypic 3D re-aggregating brain cell cultures, containing all brain cell types, were found to be well suited for OMICs analyses after both acute and long term treatment. The obtained data suggest that an in vitro ITS based on the information obtained from BBB studies and combined with metabolomics, proteomics and neuronal electrical activity measurements performed in stable in vitro neuronal cell culture systems, has high potential to improve current in vitro drug-induced neurotoxicity evaluation.

Amiodarone biokinetics, the formation of its major oxidative metabolite and neurotoxicity after acute and repeated exposure of brain cell cultures.

The difficulty in mimicking nervous system complexity and cell-cell interactions as well as the lack of kinetics information has limited the use of in vitro neurotoxicity data. Here, we assessed the biokinetic profile as well as the neurotoxicity of Amiodarone after acute and repeated exposure in two advanced rodent brain cell culture models, consisting of both neurons and glial cells organized in 2 or 3 dimensions to mimic the brain histiotypic structure and function. A strategy was applied to evidence the abiotic processes possibly affecting Amiodarone in vitro bioavailability, showing its ability to adsorb to the plastic devices. At clinically relevant Amiodarone concentrations, known to induce neurotoxicity in some patients during therapeutic treatment, a complete uptake was observed in both models in 24 h, after single exposure. After repeated treatments, bioaccumulation was observed, especially in the 3D cell model, together with a greater alteration of neurotoxicity markers. After 14 days, Amiodarone major oxidative metabolite (mono-N-desethylamiodarone) was detected at limited levels, indicating the presence of active drug metabolism enzymes (i.e. cytochrome P450) in both models. The assessment of biokinetics provides useful information on the relevance of in vitro toxicity data and should be considered in the design of an Integrated Testing Strategy aimed to identify specific neurotoxic alerts, and to improve the neurotoxicity assay predictivity for human acute and repeated exposure.