In-vitro Approaches to Investigate the Detrimental Effect of Light on Dopaminergic Neurons.

Our recent study revealed that fluorescent lamp light can penetrate deep into the brain of mice and rats leading to the development of typical histological characteristics associated with Parkinson's disease such as the loss of dopamine neurons in the substantia nigra. Monochromatic LED lights were thus used in this work to deepen our knowledge on the effects of the major wavelength peaks of fluorescent light on mouse and human dopaminergic cells. In particular, we exposed immortalized dopaminergic MN9D neuronal cells, primary cultures of mouse mesencephalic dopaminergic cells and human dopaminergic neurons differentiated from induced pluripotent stem cells (hiPSC) to different LED light wavelengths.

Melanocortin receptor 4 as a new target in melanoma therapy: Anticancer activity of the inhibitor ML00253764 alone and in association with B-raf inhibitor vemurafenib.

The aim of our study is to investigate in vitro and in vivo MC4R as a novel target in melanoma using the selective antagonist ML00253764 (ML) alone and in combination with vemurafenib, a B-rafV600E inhibitor. The human melanoma B-raf mutated A-2058 and WM 266-4 cell lines were used. An MC4R null A-2058 cell line was generated using a CRISPR/Cas9 system.

Morphological alterations of the reticular thalamic nucleus in Engrailed-2 knockout mice.

The reticular thalamic nucleus (Rt) is a sheet of neurons that surrounds the dorsal thalamus laterally, along its dorso-ventral and rostro-caudal axes. It consists of inhibitory neurons releasing gamma-aminobutyric acid (GABA). This nucleus participates in the circuitry between the thalamus and the cerebral cortex, and its impairment is associated with neuro-psychiatric disorders.

Rho-inhibition and neuroprotective effect on rotenone-treated dopaminergic neurons in vitro.

Mesencephalic cell cultures are a good model to study the vulnerability of dopaminergic neurons and reproduce, in vitro, experimental models of Parkinson's disease. Rotenone associated as an environmental neurotoxin related to PD, is able to provoke dopaminergic neuron degeneration by inhibiting complex I of the mitochondrial respiratory chain and by inducing accumulation of α-synuclein. Recently, rotenone has been described to activate RhoA, a GTPase protein.

Melanocortin Receptor-4 and Glioblastoma Cells: Effects of the Selective Antagonist ML00253764 Alone and in Combination with Temozolomide In Vitro and In Vivo.

Currently, no description of melanocortin receptor-4 (MC4R) expression or activity is available in human cancer cells, including glioblastoma (GBM). The aim of this study is to evaluate the presence of MC4Rs in GBM cells and the selective inhibition of their activity through the MC4R antagonist ML00253764 alone and in association with temozolomide in vitro and in vivo. MC4R genotyping and gene expression were performed on human GBM cells (U-87 and U-118) with real-time PCR.

Fluorescent light induces neurodegeneration in the rodent nigrostriatal system but near infrared LED light does not.

We investigated the effects of continuous artificial light exposure on the mouse substantia nigra (SN). A three month exposure of C57Bl/6J mice to white fluorescent light induced a 30% reduction in dopamine (DA) neurons in SN compared to controls, accompanied by a decrease of DA and its metabolites in the striatum. After six months of exposure, neurodegeneration progressed slightly, but the level of DA returned to the basal level, while the metabolites increased with respect to the control.

Effect of itraconazole on mouse mesencephalic neurons.

Neuronal cells have complex geometrical shapes, long processes such as axons and dendrites, and as a response to specific stimuli, they go through polarized neuronal migration that influences connectivity and information processing. Recently, it has been discovered that itraconazole, a widely used systemic antifungal drug, has an effect on cell morphology, acting as an inhibitor of the morphogen Sonic Hedgehog (Shh) and of the mammalian target of rapamycin mTOR pathways. In this paper we evaluated the effect of itraconazole on mouse mesencephalic dopaminergic neurons following their neurite outgrowth and functional activity by [(3)H] DA uptake.

Serotonin abnormalities in Engrailed-2 knockout mice: New insight relevant for a model of Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is a congenital neurodevelopmental behavioral disorder that appears in early childhood. Recent human genetic studies identified the homeobox transcription factor, Engrailed 2 (EN2), as a possible ASD susceptibility gene. En2 knockout mice (En2-/-) display subtle cerebellar neuropathological changes and reduced levels of tyrosine hydroxylase, noradrenaline and serotonin in the hippocampus and cerebral cortex similar to those ones which have been observed in the ASD brain.

Acetaldehyde and parkinsonism: role of CYP450 2E1.

The present review update the relationship between acetaldehyde (ACE) and parkinsonism with a specific focus on the role of P450 system and CYP 2E1 isozyme particularly. We have indicated that ACE is able to enhance the parkinsonism induced in mice by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, a neurotoxin able to damage the nigrostriatal dopaminergic pathway. Similarly diethyldithiocarbamate, the main metabolite of disulfiram, a drug widely used to control alcoholism, diallylsulfide (DAS) and phenylisothiocyanate also markedly enhance the toxin-related parkinsonism.

A novel method to produce immobilised biomolecular concentration gradients to study cell activities: design and modelling.

It is well known that many cell functions are activated by chemical signals with a time and space-dependent profile. To mimic these profiles in vitro, it is necessary to develop a system that is able to generate concentration gradients with a resolution similar to that perceived by cells, which is around nanomolar with a spatial resolution of a few tens of microns. Many devices capable of generating steady-state concentration gradients have been developed using continuous flow micro-fluidic techniques.

Human dental pulp stem cells protect mouse dopaminergic neurons against MPP+ or rotenone.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive death of substantia nigra dopaminergic neurons that results in a regional loss of striatal dopamine (DA) levels. Dental pulp contains ex vivo-expandable cells called dental pulp stem cells (DPSCs), with the capacity to differentiate into multiple cell lineages. More interestingly, due to their embryonic origin, DPSCs express neurotrophic factors such as brain-derived neurotrophic factor, nerve growth factor and glial cell-derived neurotrophic factor.

Apomorphine offers new insight into dopaminergic neuron vulnerability in mesencephalic cultures.

The mechanism by which the dopamine neurons of the substantia nigra pars compacta degenerate in Parkinson's disease, is partly unknown. Dopamine could be implicated in this phenomenon, and in order to explain its toxicity several hypotheses have been suggested. The similarity between apomorphine and dopamine as regards their chemical, pharmacological and toxicological properties provided a basis for investigating the nature of the toxicity of the former agent.

Role of CYP2E1 in the mouse model of MPTP toxicity.

It has been shown that diethyldithiocarbamate (DDC) potentiates 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity in mice as a result of increased levels of 1-methyl-4-phenylpyridinium ion (MPP(+)) in the striatum. Brain CYP2E1 inhibition by DDC in C57Bl mice was responsible for increased toxicity and striatal MPP(+) accumulation. However, CYP2E1-null mice did not show any enhanced sensitivity to MPTP or any MPP(+) accumulation.

Involvement of cytochrome P450 2E1 in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of Parkinson's disease.

Elucidation of the biochemical steps leading to the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced degeneration of the nigrostriatal dopamine (DA) pathway has provided new clues to the pathophysiology of Parkinson's disease. In line with the enhancement of MPTP toxicity by diethyldithiocarbamate (DDC), here we demonstrate how other cytochrome P450 (CYP) 2E1 inhibitors, such as diallyl sulphide (DAS) and phenylethylisothiocyanate (PIC), also potentiate the selective DA neurone degeneration in C57/bl mice. In addition, we show that CYP 2E1 is present in the brain and in the basal ganglia of this mouse strain, as measured by RT-PCR, western blot analysis and immunohistochemistry.

Dose-dependent induction of apoptosis by R-apomorphine in CHO-K1 cell line in culture.

A variety of mechanisms have been proposed as explanations for the distinctive neuropathology of Parkinson's disease, such as increased iron levels, increased oxidant stress or decreased antioxidant defences. The vulnerability of dopamine-containing neurons towards cell death has attracted much attention to the dopamine molecule itself as one of the probable neurotoxic factors leading to neurodegeneration. The similarity between apomorphine and dopamine with regards to their chemical, pharmacological and toxicological properties provided a basis for investigating the nature of the toxicity of the former agent.

Dextromethorphan prevents the diethyldithiocarbamate enhancement of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity in mice.

In this report we show that dextromethorphan, a non-opioid cough suppressant, prevents the neurodegeneration of dopaminergic neurons in the substantia nigra of mice treated with diethyldithiocarbamate (DDC) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). This effect is further substantiated by the assessment of dopamine (DA) content in the striatum of these animals. Dextromethorphan does not attenuate the striatal DA fall induced by MPTP alone but completely prevents DDC-induced enhancement after the combined treatment.