Nox1-inhibitor-based therapeutic approach to prevent Parkinson’s Disease progression

• Autor(a) principal: Diogo, João José Campos
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.6/12271
• topic: Cloreto de Colina; Doença do Parkinson; Inibidor Nox1; Nadph Oxidase; Neurónios Dopaminérgicos; Stress Oxidativo; Domínio/Área Científica::Engenharia e Tecnologia::Biotecnologia

Parkinson's disease (PD) is a neurodegenerative disease and is characterized by the loss of dopaminergic neurons in the nigrostriatal pathway, leading to a decrease in the levels of the neurotransmitter, dopamine. The loss of this type of neuron is associated with several pathological mechanisms, including a significant increase in oxidative stress, caused by an increase in the levels of reactive oxygen species (ROS) produced by the enzymes adenine and nicotinamide dinucleotide (NADPH) oxidases (NOX), and in particular by isoform 1 (NOX1). The currently available therapies aim to reduce the symptoms associated with the disease, and therapeutic approaches that reduce the progression of the disease associated with a large increase in the debilitating degree of patients and reduced response to symptomatic therapies, remain a need to be addressed. The use of specific NOX1 inhibitors, therefore, has a high therapeutic potential to reduce disease progression. Several NOX1 inhibitors have been tested by us, one of which has been shown to have a high dopaminergic neuroprotective potential. However, this inhibitor is not soluble in aqueous solvents, and the vehicle used for its dissolution has a high degree of toxicity to the nigrostriatal system in rodents. Thus, it was necessary, without changing the chemical structure of the inhibitory molecule, to reformulate this inhibitor to change its solubility characteristics. The reformulation achieved made the inhibitor soluble in saline, and in this work the objective was to test the cytotoxicity of the NOX1 inhibitor reformulation (RefN1inh) and to test its neuroprotective capacity in vitro models of PD induced by the exposure of the N27 cell line to two specific neurotoxins, 6-hydroxydopamine (6OHDA) and 1-methyl-4-phenylpyridinium (MPP+). The results of these tests, allowed to conclude that the presence of RefN1inh, did not induce a toxic effect in the neurons, having significantly reduced the neuronal death induced by both toxins. Since the basis of the reformulation includes the presence of choline chloride, complementary tests were carried out to exclude a possible contribution of this to the neuroprotective effect observed by RefN1inh. The results allowed us to conclude that choline chloride does not have a toxic effect on dopaminergic neurons, and is not able to reverse the neurotoxic effect of 6OHDA or MPP+, allowing to exclude its potential contribution to the protection exerted by RefN1inh. In short, all of these results allow us to ascertain that the reformulation did not alter the neuroprotective effect of N1inh, serving as a basis for advancing the validation of RefN1inh in vivo models of the disease.