Dados do Trabalho

Título

Phosphoproteomic characterization of brain tissue from patients with mesial temporal lobe epilepsy: a window into disease mechanism and progression

Introdução

Introduction: Mesial temporal lobe epilepsy (MTLE) accounts for around 40% of all epilepsies in adult patients, many of whom do not respond to treatment with antiseizure medication. It is well known that protein phosphorylation regulates several essential functions, including brain development and normal neuronal activity. Using large-scale phosphoproteomics, it is possible to identify multiple phosphorylation sites in proteins obtained from normal and disease tissues at distinct stages. Identifying differences in protein phosphorylation may lead to new insights into the underlying mechanisms of disease.

Objetivo

Objective: To determine the phosphoproteome of brain tissue obtained by surgery of patients with pharmacoresistant MTLE.

Método

Methods: We used state-of-the-art mass spectrometry-based proteomics, using a Thermo ScientificTM Orbitrap EclipseTM TribridTM to evaluate the amygdala, hippocampus, and temporal lobe of patients with MTLE divided into two groups: i) less than 20 years of disease duration (n=5), and ii) more than 40 years of disease at the time of epilepsy surgery (n=7). All surgical specimens had confirmed hippocampal sclerosis (HS) by histopathological examination. Data obtained were analyzed using the ProteomeDiscoverer 2.4 and R software.

Resultados

Results: Overall, the phosphoproteome was not different in the two groups of patients divided by disease duration. However, there were differences among the three structures analyzed, especially the loss of phosphorylation sites in the hippocampus. Furthermore, hippocampal dephosphorylation was observed in proteins involved in abnormal myelination, neurogenesis, and synaptic signaling in neurons and glial cells. Also, kinase activity analysis indicates the downregulation of three MAPK kinases of the Ras-Raf-MEK-ERK pathway in the hippocampus.

Conclusão

Conclusions: Our results indicate that changes in protein phosphorylation are a relevant and still unexplored post-translational mechanism regulating gene function in MTLE+HS. However, we found no evidence that changes in protein phosphorylation is linked to HS's progression.

Palavras-chave

Mesial Temporal Lobe Epilepsy; Phosphoproteomics; Hippocampal Sclerosis