Introduction: Temporal Lobe Epilepsy (TLE) is a disorder caused by neuronal electrical imbalance, clinically manifested by spontaneous and recurrent seizures1,2. Its pathogenesis involves channelopathies of calcium channels, which contributes to hyperexcitability and hypersynchrony in TLE3 . About 30% of patients do not respond to drug treatment4 , making it necessary to develop new therapeutic alternatives, such as cell therapy. This work aimed to evaluate the modulation of mesenchymal stem cells (MSCs) in the calcium channel CACNA1G (Cav3.1) gene expression. Methods: MSCs were extracted from Wistar rats bone marrow and then cultured and transplanted intravenously and intranasally in the control and epileptic groups. The brain was collected 1 and 7 days after transplantation to analyze gene expression. Results: The analysis showed that treated animals had greater gene expression, compared to animals not treated in the epileptic and control group, in both days and administration routes. Furthermore, epileptic animals that were not treated had a low or negative expression of the gene. The epileptic rats that were treated, on the other hand, had a marked increase in gene expression e in the prefrontal cortex. Conclusion: This up-regulation noted on the treated groups raises the hypothesis that MSCs would be using these channels to modify the microenvironment5 , intensifying Cav.3.1 transcription and contributing to tissue regeneration by neurodifferentiation6,7. This is supported by the increase in the calcium influx present in the early stages of neuronal maturation8,9. Thus, MSCs can modulate gene expression in the pilocarpine-induced animal’s brain, making Cav3.1 a target to be explored in epilepsy.

Background: Temporal Lobe Epilepsy (TLE), by firing of neuronal populations, leads to spontaneous and recurrent seizures1 . As 30% of TLE patients do not respond to pharmacotherapy2,3, it is necessary to search for alternatives. Mesenchymal stem cells (MSCs) are an attractive approach in this context, due to their less invasive character and its ability to modulate diseased niches. Objective: Analyze the gene expression related to the cation-chloride cotransporter KCC2 in TLE induced by pilocarpine model in rats. Design and Setting: Experimental study, Brain Institute of Rio Grande do Sul. Methods: MSCs were extracted from the bone marrow of Wistar rats, cultured and transplanted intravenously and intranasally into healthy and epileptic Wistar rats. Results: It was observed a decrease in the expression of KCC2 in the brain of the animals at 1-day post-transplant, which refers to a down-regulation, and an increase at 7 days post-transplant, representing an up-regulation. The loss of function of KCC2 decreases the release of chloride with difficulty in inhibiting GABAergic inhibition, resulting in hyperexcitability of neuronal circuits. In this case, MSCs can promote rearrangement in gamma-aminobutyric acid-mediated inhibition, reducing hyperexcitability and hypersynchronicity. Hence, KCC2 down-regulation is associated with epileptiform activity, while up-regulation can be related to the MSCs effects. Also, KCC2 expression showed a kind of pattern at 1-day post- transplant in both routes of administration, providing the possibility that KCC2 can be explored as a biomarker for epilepsy. Conclusion: KCC2 is an important target for epilepsy, as well MSCs have a modulatory function on the levels of the expression of this gene in animals induced to status epilepticus by pilocarpine.

Introduction: temporal lobe epilepsy is a disorder in which synchronized and rhythmic neural firing causes spontaneous recurrent seizures (1). Refractoriness due to this condition reaches 30% of its carriers (2,3). The search for therapeutic alternatives to help cope with this disease are extremely important. Mesenchymal stem cells (MSCs) appear as a plausible treatment option, as they present a less invasive approach and due to their niche modulating character (4,5). Objectives: this study aimed to quantify the gene expression of cation-chloride cotransporter NKCC1 encoded by the SLC12A2 gene in the encephalic tissue of pilocarpine-induced epileptic rats (6,7). Design: experimental study, brain institute of Rio Grande do Sul. Methods: MSCs were obtained from the bone marrow of Wistar rats, cultured, and transplanted through intravenous injection into control and epileptic Wistar rats. The rats were divided between control group, MSCs treated group, and pilocarpine group, containing 8 individuals each (8). Expression analysis was performed using real-time polymerase chain reaction. Results: for both 1 day and 7 days post-transplantation, an increase in the NKCC1 expression in both control and epileptic treated groups as compared to its expression in untreated epileptic and control groups with special attention to the amygdala, the hippocampus and the prefrontal cortex. Conclusion: MSCs stimulated expression of NKCC1 in brain structures of rats induced by pilocarpine to epilepsy. This corroborates the hypothesis of neuroprotective effects and modulating properties of stem cells and may point to more mechanisms for investigating the functioning and collaboration of these cells as a treatment for epilepsy.

Introduction: Temporal Lobe Epilepsy (TLE) is the most common refractory epilepsy, and it is characterized by abnormal firing of a population of neurons in the brain, and by cognitive deficit1 . This abnormal intrinsic phenomenon can cause deregulation of the T-type calcium channels, increasing neuronal excitability, leading to structural changes in the Central Nervous System2 . Mesenchymal Stem Cells (MSCs) are a therapeutic alternative for the TLE for they can modulate neurotransmitters liberation, reducing neuronal death and increasing neurogenesis3,4,5. The present study analyzed MSCs effects on gene expression of T-type calcium channel CACNA1H in the brain of pilocarpine-induced TLE animal models. Methods: The MSCs were obtained from the bone marrow of Wistar rats, cultured, and transplanted intravenously and intranasally. The animals were separated into the following groups: control and pilocarpine-induced status epilepticus, then they were euthanized 1- and 7-days post-transplant for gene expression analysis. Results: The results show that 1-day post-transplant there was no difference in the CACNA1H gene expression between the MSC-treated pilocarpine groups and the control and untreated pilocarpine groups. Subsequently 7-days posttransplant, the treated groups showed greater expression of the gene in both means of administration. Moreover, there was an increase in CACNA1H gene expression in the prefrontal cortex of the treated pilocarpine group, which makes us conjecture a mechanism of greater need for its transcription in this area. Conclusion: Thus, MSCs were able to modulate the expression of the CACNA1H gene in the brain, increasing its importance as a target for future studies on epilepsy therapies involving cells.

Introduction: Temporal Lobe Epilepsy (TLE) can be identified by synchronized and rhythmic firing of neuronal populations that results in spontaneous and recurrent seizures in individuals affected by it1 . This type of epilepsy is clinically relevant because of its high incidence and refractoriness rate2,3. Thus, the search for therapeutic alternatives becomes important. Due to its benefits and less invasive administration, the mesenchymal stem cells (MSCs)4 appears as a possible therapeutic alternative, because can stimulate and provide a favorable niche for recovery based on their paracrine activities5 . Objectives: The present work aim to highlight the effect promoted by MSCs on the transcription of mRNA of the NKCC1 gene in the TLE induced by pilocarpine model in rats. NKCC1 plays a role in controlling the potential reversal of current and voltage signals executed by Gamma-aminobutyric acid receptors, contributing to inhibitory GABAergic efficacy6 . Design and setting: Experimental design was held at the Pontifical Catholic University of Rio Grande do Sul. Methods: Bone marrow cells were extracted from donor rats, then cultured and transplanted intranasally in animals induced to status epilepticus by pilocarpine7,11. Results: It was observed the ability of the MSCs to alter the amount of transcripts in the brain of the animals. When analyzing the stratified areas of the brain, an increase in NKCC1 expression12 was observed directly to the amygdalas and hippocampi, which are limbic lobe structures affected in epilepsy. Conclusion: MSCs had a modulatory function in the levels of gene expression of cation- chloride co-transporter NKCC1 during acute phase of epilepsy.