Extracellular electrophysiology on clonal human β-cell spheroids

BackgroundPancreatic islets are important in nutrient homeostasis and improved cellular models of clonal origin may very useful especially in view of relatively scarce primary material. Close 3D contact and coupling between β-cells are a hallmark of physiological function improving signal/noise ratios. Extracellular electrophysiology using micro-electrode arrays (MEA) is technically far more accessible than single cell patch clamp, enables dynamic monitoring of electrical activity in 3D organoids and recorded multicellular slow potentials (SP) provide unbiased insight in cell-cell coupling.ObjectiveWe have therefore asked whether 3D spheroids enhance clonal β-cell function such as electrical activity and hormone secretion using human EndoC-βH1, EndoC-βH5 and rodent INS-1 832/13 cells.MethodsSpheroids were formed either by hanging drop or proprietary devices. Extracellular electrophysiology was conducted using multi-electrode arrays with appropriate signal extraction and hormone secretion measured by ELISA. ResultsEndoC-βH1 spheroids exhibited increased signals in terms of SP frequency and especially amplitude as compared to monolayers and even single cell action potentials (AP) were quantifiable. Enhanced electrical signature in spheroids was accompanied by an increase in the glucose stimulated insulin secretion index. EndoC-βH5 monolayers and spheroids gave electrophysiological profiles similar to EndoC-βH1, except for a higher electrical activity at 3 mM glucose, and exhibited moreover a biphasic profile. Again, physiological concentrations of GLP-1 increased AP frequency. Spheroids also exhibited a higher secretion index. INS-1 cells did not form stable spheroids, but overexpression of connexin 36, required for cell-cell coupling, increased glucose responsiveness, dampened basal activity and consequently augmented the stimulation indexConclusionIn conclusion, spheroid formation enhances physiological function of the human clonal β-cell lines and these models may provide surrogates for primary islets in extracellular electrophysiology

Vertical Organic Electrochemical Transistors and Electronics for Low Amplitude Micro‐Organ Signals

Electrical signals are fundamental to key biological events such as brain activity, heartbeat, or vital hormone secretion. Their capture and analysis provide insight into cell or organ physiology and a number of bioelectronic medical devices aim to improve signal acquisition. Organic electrochemical transistors (OECT) have proven their capacity to capture neuronal and cardiac signals with high fidelity and amplification. Vertical PEDOT:PSS-based OECTs (vOECTs) further enhance signal amplification and device density but have not been characterized in biological applications. An electronic board with individually tuneable transistor biases overcomes fabrication induced heterogeneity in device metrics and allows quantitative biological experiments. Careful exploration of vOECT electric parameters defines voltage biases compatible with reliable transistor function in biological experiments and provides useful maximal transconductance values without influencing cellular signal generation or propagation. This permits successful application in monitoring micro-organs of prime importance in diabetes, the endocrine pancreatic islets, which are known for their far smaller signal amplitudes as compared to neurons or heart cells. Moreover, vOECTs capture their single-cell action potentials and multicellular slow potentials reflecting micro-organ organizations as well as their modulation by the physiological stimulator glucose. This opens the possibility to use OECTs in new biomedical fields well beyond their classical applications.Transistors multimodaux sensibles aux ions à polymères ambivalents pour biocapteurs hybridesCapteurs bio-électroniques intégrant l'algorithme des îlots pour le contrôle de la glycémie en boucle ouverte et fermé

Capteurs bio-électroniques pour le contrôle de la glycémie en boucle ouverte et fermée

In diabetes mellitus (DM), continuous glucose monitoring (CGM) linked to insulindelivery presents a major advance but is still limited by current algorithms and thenature of glucose sensors. DIABLO is a multidisciplinary project from diabetology, isletbiology, and microelectronics to automation control, with the objective to establish anew model of CGM (i) by high-resolution techniques to decipher and model islet'sendogenous algorithms, (ii) by design of novel control algorithms inspired byaeronautics and (iii) by the proof of concept of maintaining glucose homeostasis bythis hybrid biosensor. DIABLO will impact research by multi-physics system modellingand healthcare technology as well as life quality in DM by novel algorithms and aninnovative module for the artificial pancreas. The project will also advance for DM andother chronic diseases monitoring of stem-cell derived therapeutic means and thedevelopment of Organs-on-Chip.Les technologies de mesure continue de la glycémie (CGM) et d'insulinothérapierévolutionnent le traitement du diabetes mellitus (DM). Les capteurs sont toutefoislimités à la mesure de glucose et les algorithmes d'insulinothérapie sont améliorables.DIABLO rassemble des diabétologues et des spécialistes de la biologie des îlots, dela microélectronique et de l'automatique, pour développer un nouvel outil de CGM.DIABLO propose: (i) des techniques de mesure et un capteur bio-électronique hauterésolution pour décoder les algorithmes endogènes des îlots,; (ii) de nouveauxalgorithmes de contrôle robustes et tolérants aux fautes, inspirés par l'avionique ; (iii)la démonstration in vivo de la capacité du capteur bio-électronique à maintenirl'homéostasie du glucose. DIABLO aura un impact sur le traitement du DM et ledéveloppement de pancréas artificiels, et facilitera aussi les approches thérapeutiquesà base de cellules souches en permettant leur caractérisation fine in situ

Biosensors for open and closed-loop glycemia control

Les technologies de mesure continue de la glycémie (CGM) et d'insulinothérapierévolutionnent le traitement du diabetes mellitus (DM). Les capteurs sont toutefoislimités à la mesure de glucose et les algorithmes d'insulinothérapie sont améliorables.DIABLO rassemble des diabétologues et des spécialistes de la biologie des îlots, dela microélectronique et de l'automatique, pour développer un nouvel outil de CGM.DIABLO propose: (i) des techniques de mesure et un capteur bio-électronique hauterésolution pour décoder les algorithmes endogènes des îlots,; (ii) de nouveauxalgorithmes de contrôle robustes et tolérants aux fautes, inspirés par l'avionique ; (iii)la démonstration in vivo de la capacité du capteur bio-électronique à maintenirl'homéostasie du glucose. DIABLO aura un impact sur le traitement du DM et ledéveloppement de pancréas artificiels, et facilitera aussi les approches thérapeutiquesà base de cellules souches en permettant leur caractérisation fine in situ.In diabetes mellitus (DM), continuous glucose monitoring (CGM) linked to insulindelivery presents a major advance but is still limited by current algorithms and thenature of glucose sensors. DIABLO is a multidisciplinary project from diabetology, isletbiology, and microelectronics to automation control, with the objective to establish anew model of CGM (i) by high-resolution techniques to decipher and model islet'sendogenous algorithms, (ii) by design of novel control algorithms inspired byaeronautics and (iii) by the proof of concept of maintaining glucose homeostasis bythis hybrid biosensor. DIABLO will impact research by multi-physics system modellingand healthcare technology as well as life quality in DM by novel algorithms and aninnovative module for the artificial pancreas. The project will also advance for DM andother chronic diseases monitoring of stem-cell derived therapeutic means and thedevelopment of Organs-on-Chip

Biosensors for open and closed-loop glycemia control

Les technologies de mesure continue de la glycémie (CGM) et d'insulinothérapierévolutionnent le traitement du diabetes mellitus (DM). Les capteurs sont toutefoislimités à la mesure de glucose et les algorithmes d'insulinothérapie sont améliorables.DIABLO rassemble des diabétologues et des spécialistes de la biologie des îlots, dela microélectronique et de l'automatique, pour développer un nouvel outil de CGM.DIABLO propose: (i) des techniques de mesure et un capteur bio-électronique hauterésolution pour décoder les algorithmes endogènes des îlots,; (ii) de nouveauxalgorithmes de contrôle robustes et tolérants aux fautes, inspirés par l'avionique ; (iii)la démonstration in vivo de la capacité du capteur bio-électronique à maintenirl'homéostasie du glucose. DIABLO aura un impact sur le traitement du DM et ledéveloppement de pancréas artificiels, et facilitera aussi les approches thérapeutiquesà base de cellules souches en permettant leur caractérisation fine in situ.In diabetes mellitus (DM), continuous glucose monitoring (CGM) linked to insulindelivery presents a major advance but is still limited by current algorithms and thenature of glucose sensors. DIABLO is a multidisciplinary project from diabetology, isletbiology, and microelectronics to automation control, with the objective to establish anew model of CGM (i) by high-resolution techniques to decipher and model islet'sendogenous algorithms, (ii) by design of novel control algorithms inspired byaeronautics and (iii) by the proof of concept of maintaining glucose homeostasis bythis hybrid biosensor. DIABLO will impact research by multi-physics system modellingand healthcare technology as well as life quality in DM by novel algorithms and aninnovative module for the artificial pancreas. The project will also advance for DM andother chronic diseases monitoring of stem-cell derived therapeutic means and thedevelopment of Organs-on-Chip

Early neurochemical modifications of monoaminergic systems in the R6/1 mouse model of Huntington's disease

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Cannabinoid 1/2 Receptor Activation Induces Strain-Dependent Behavioral and Neurochemical Changes in Genetic Absence Epilepsy Rats From Strasbourg and Non-epileptic Control Rats

: Childhood absence epilepsy (CAE) is characterized by absence seizures, which are episodes of lack of consciousness accompanied by electrographic spike-wave discharges. About 60% of children and adolescents with absence seizures are affected by major neuropsychological comorbidities, including anxiety. Endocannabinoids and monoamines are likely involved in the pathophysiology of these CAE psychiatric comorbidities. Here, we show that the synthetic cannabinoid receptor type 1/2 (CB1/2R) agonist WIN 55,212-2 (2 mg/kg) has a strain-dependent effect on anxiety-like and motor behavior when assess in the hole board test and cerebral monoaminergic levels in Genetic Absence Epilepsy Rats from Strasbourg (GAERS) and their non-epileptic control (NEC) rat strain. Using quantitative and Temporal pattern (T-pattern) analyses, we found that WIN 55,212-2 did not affect the emotional status of GAERS, but it was anxiolytic in NEC. Conversely, WIN 55,212-2 had a sedative effect in GAERS but was ineffective in NEC. Moreover, vehicle-treated GAERS more motivated to explore by implementing more complex and articulated strategies. These behavioral changes correlate with the reduction of 5-HT in the hippocampus and substantia nigra (SN) and noradrenaline (NA) in the entopeduncular nucleus (EPN) in vehicle-treated GAERS compared to NEC rats, which could contribute to their low anxiety status and hypermotility, respectively. On the other hand, the increased level of NA in the EPN and 5-HT in the SN is consistent with an activation of the basal ganglia output-mediated motor suppression observed in WIN 55,212-2-treated GAERS rats. These data support the view of a strain-dependent alteration of the endocannabinoid system in absence epilepsy by adding evidence of a lower emotional responsiveness and a basal ganglia hypersensitivity to cannabinoids in GAERS compared to NEC rats

Dynamic Uni- and Multicellular Patterns Encode Biphasic Activity in Pancreatic Islets

Biphasic secretion is an autonomous feature of many endocrine micro-organs to fulfill physiological demands. The biphasic activity of islet beta-cells maintains glucose homeostasis and is altered in type 2 diabetes. Nevertheless, underlying cellular or multicellular functional organizations are only partially understood. High-resolution noninvasive multielectrode array recordings permit simultaneous analysis of recruitment, of single-cell, and of coupling activity within entire islets in long-time experiments. Using this unbiased approach, we addressed the organizational modes of both first and second phase in mouse and human islets under physiological and pathophysiological conditions. Our data provide a new uni- and multicellular model of islet beta-cell activation: during the first phase, small but highly active beta-cell clusters are dominant, whereas during the second phase, electrical coupling generates large functional clusters via multicellular slow potentials to favor an economic sustained activity. Postprandial levels of glucagon-like peptide 1 favor coupling only in the second phase, whereas aging and glucotoxicity alter coupled activity in both phases. In summary, biphasic activity is encoded upstream of vesicle pools at the micro-organ level by multicellular electrical signals and their dynamic synchronization between beta-cells. The profound alteration of the electrical organization of islets in pathophysiological conditions may contribute to functional deficits in type 2 diabetes