Search results for " potential"

The interplay between genetic and bioelectrical signaling permits a spatial regionalisation of membrane potentials in model multicellular ensembles

2016

AbstractThe single cell-centred approach emphasises ion channels as specific proteins that determine individual properties, disregarding their contribution to multicellular outcomes. We simulate the interplay between genetic and bioelectrical signals in non-excitable cells from the local single-cell level to the long range multicellular ensemble. The single-cell genetic regulation is based on mean-field kinetic equations involving the mRNA and protein concentrations. The transcription rate factor is assumed to depend on the absolute value of the cell potential, which is dictated by the voltage-gated cell ion channels and the intercellular gap junctions. The interplay between genetic and ele…

Cell-cell bioelectrical interactions and local heterogeneities in genetic networks: a model for the stabilization of single-cell states and multicell…

2018

Genetic networks operate in the presence of local heterogeneities in single-cell transcription and translation rates. Bioelectrical networks and spatio-temporal maps of cell electric potentials can influence multicellular ensembles. Could cell-cell bioelectrical interactions mediated by intercellular gap junctions contribute to the stabilization of multicellular states against local genetic heterogeneities? We theoretically analyze this question on the basis of two well-established experimental facts: (i) the membrane potential is a reliable read-out of the single-cell electrical state and (ii) when the cells are coupled together, their individual cell potentials can be influenced by ensemb…

The mitochondrial antioxidant SS-31 increases SIRT1 levels and ameliorates inflammation, oxidative stress and leukocyte-endothelium interactions in t…

2018

AbstractThere is growing focus on mitochondrial impairment and cardiovascular diseases (CVD) in type 2 diabetes (T2D), and the development of novel therapeutic strategies in this context. It is unknown whether mitochondrial-targeting antioxidants such as SS-31 protect sufficiently against oxidative damage in diabetes. We aimed to evaluate if SS-31 modulates SIRT1 levels and ameliorates leukocyte-endothelium interactions, oxidative stress and inflammation in T2D patients. Anthropometric and metabolic parameters were studied in 51 T2D patients and 57 controls. Production of mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential, glutathione content, leukocyte-endotheliu…

Transformation of Amorphous Polyphosphate Nanoparticles into Coacervate Complexes: An Approach for the Encapsulation of Mesenchymal Stem Cells.

2018

Inorganic polyphosphate [polyP] has proven to be a promising physiological biopolymer for potential use in regenerative medicine because of its morphogenetic activity and function as an extracellular energy-donating system. Amorphous Ca2+ -polyP nanoparticles [Ca-polyP-NPs] are characterized by a high zeta potential with -34 mV (at pH 7.4). This should contribute to the stability of suspensions of the spherical nanoparticles (radius 94 nm), but make them less biocompatible. The zeta potential decreases to near zero after exposure of the Ca-polyP-NPs to protein/peptide-containing serum or medium plus serum. Electron microscopy analysis reveals that the particles rapidly change into a coacerv…

Cytotoxicity of 18 Cameroonian medicinal plants against drug sensitive and multi-factorial drug resistant cancer cells

2018

Abstract Ethnopharmacological relevance Cameroonian medicinal plants are traditionally used to treat many ailments, including cancer and related diseases. Cancer is characterized as a condition with complex signs and symptoms. It has been recommended that ethnopharmacological usages such as immune and skin disorders, inflammatory, infectious, parasitic and viral diseases should be taken into account when selecting plants for anticancer screenings, since these reflect disease states bearing relevance to cancer or cancer-like symptoms. Aim of the study The present study aims at investigating 20 methanol extracts from 15 Cameroonian medicinal plants on a panel of human cancer cell lines, inclu…

2016

Neuronal activity has been shown to be essential for the proper formation of neuronal circuits, affecting developmental processes like neurogenesis, migration, programmed cell death, cellular differentiation, formation of local and long-range axonal connections, synaptic plasticity or myelination. Accordingly, neocortical areas reveal distinct spontaneous and sensory-driven neuronal activity patterns already at early phases of development. At embryonic stages, when immature neurons start to develop voltage-dependent channels, spontaneous activity is highly synchronized within small neuronal networks and governed by electrical synaptic transmission. Subsequently, spontaneous activity pattern…

Alterations in reelin and reelin receptors in Down syndrome.

2019

Reelin is an extracellular matrix glycoprotein that modulates synaptic function and plasticity, with a crucial role in neuronal migration. Changes in the expression of this protein have been reported in neurodegenerative diseases, such as Alzheimer's disease (AD). This molecule is produced by Cajal-Retzius neurons during development and by inhibitory neurons in the adult nervous system. Individuals with Down syndrome (DS) present an early development of AD; therefore, we analyzed the alterations in this molecule and its receptors in the murine model for DS Ts65Dn as well as in human with DS. We performed immunofluorescence analysis for reelin and its receptors very-low-density lipoprotein r…

Homeostatic interplay between electrical activity and neuronal apoptosis in the developing neocortex

2017

An intriguing feature of nervous system development in most animal species is that the initial number of generated neurons is higher than the number of neurons incorporated into mature circuits. A substantial portion of neurons is indeed eliminated via apoptosis during a short time window - in rodents the first two postnatal weeks. While it is well established that neurotrophic factors play a central role in controlling neuronal survival and apoptosis in the peripheral nervous system (PNS), the situation is less clear in the central nervous system (CNS). In postnatal rodent neocortex, the peak of apoptosis coincides with the occurrence of spontaneous, synchronous activity patterns. In this …

Allopregnanolone augments epileptiform activity of an in-vitro mouse hippocampal preparation in the first postnatal week.

2019

Abstract In the immature brain the neurotransmitter γ-amino butyric acid (GABA) mediates a membrane depolarization and can contribute to both, inhibition and excitation. Therefore the consequences of a positive modulation of GABA(A) receptors by neurosteroids on epileptiform activity are hard to predict. In order to analyze whether neurosteroids attenuate or exaggerate epileptiform activity in the immature brain, we investigated the effect of the neurosteroid allopregnanolone on epileptiform activity in an in-toto hippocampus preparation of early postnatal mice (postnatal days 4–7) using field potential recordings. These in-vitro experiments revealed that 0.5 μmol/L allopregnanolone had no …

Binge-like ethanol treatment in adolescence impairs autophagy and hinders synaptic maturation: Role of TLR4.

2018

Abstract Adolescence is a developmental period of brain maturation in which remodeling and changes in synaptic plasticity and neural connectivity take place in some brain regions. A different mechanism participates in adolescent brain maturation, including autophagy processes that play a role in synaptic development and plasticity. Alcohol is a neurotoxic compound whose abuse in adolescence causes TLR4 response activation by triggering neuroinflammation, neural damage and behavioral alterations. However, the potential participation of autophagy in long-term neurochemical and cognitive dysfunctions induced by binge ethanol drinking in adolescence is uncertain. We therefore evaluated whether …