MicroRNA Deregulation Is Involved in Microglial Activation in the Pilocarpine Induced Epilepsy Model (IN9-2.003)

OBJECTIVE: The aim of the present study was to analyze the expression of miR-124 in the acute phase of the pilocarpine epilepsy model. Thus, investigating whether abnormalities of microglial activation, usually observed in this model, could be mediated by microRNA deregulation. BACKGROUND: MicroRNAs regulate gene expression and are important in many key biological functions such as development, oncogenesis and inflammation. One microRNA, miR-124, is known to be expressed exclusively in the central nervous system and has been implicated in the maintenance of microglial cells in a non-activated, or quiescent, state. It is well known that activation of microglia must be properly and tightly regulated to maintain normal tissue homeostasis, avoiding tissue damage. DESIGN/METHODS: We obtained total RNA from hippocampus of animals at 1, 3, 6, and 24 hours, as well as 5 days after induction of status epilepticus (SE), and from control animals. We quantified expression of miR-124 by quantitative real-time PCR. Only tissue obtained from rats which presented SE were used in our experiments. RESULTS: We found that expression of miR-124 significantly decreased after SE, about 60%, in comparison with control samples. MiR-124 expression was decreased already at 1h after SE and remained low until 5 days after SE. CONCLUSIONS: Our results indicate that regulation by microRNA, especially by miR-124, can play a role in microglia activation after SE induced by pilocarpine. Thus, opening the possibility of using microRNA-based therapies in epilepsy. Supported by: FAPESP. Disclosure: Dr. Matos has nothing to disclose. Dr. Peluzzo has nothing to disclose. Dr. Pascoal has nothing to disclose. Dr. Gilioli has nothing to disclose. Dr. Lopes-Cendes has nothing to disclose.