Joaquin N. Lugo, Ph.D. - US grants

People with Fetal Alcohol Sydrome (FAS) are known to have cognitive deficits. However, in comparison to individuals with similar cognitive deficits but were not exposed to alcohol, FAS individuals show more deficits in social behavior. This observation and others have lead to the question of how alcohol affects social behavior. In addition, the amygdala is thought to play an important role in social behavior and is adversely affected by the perinatal-alcohol exposure. This research will investigate the effect of prenatal alcohol exposure during three trimester equivalents on the amygdala. Unbiased-stereology will be used to compare volume differences in the amygdala nuclei. It is goal of this experiment to provide evidence for a neural mechanism for the deficits induced by alcohol exposure during development. In addition, possible gender differences will also be investigated.

[unreadable] DESCRIPTION (provided by applicant): Prolonged, continuous seizure activity (status epilepticus) is associated with significant mortality and morbidity, particularly in children. In humans and animal models of epilepsy the immature brain is highly susceptible to seizures. The neurotransmitter systems in the developing brain are weighted toward excitation and the inhibitory systems present in developing brain to dampen excitation are not well characterized. In adult brain potassium channels are major determinants of membrane excitability in neurons. One particular potassium channel, Kv4.2 is localized to the dendrites of hippocampal neurons where they form the transient A-type K+ current. In this region where the neurons receive synaptic input, the voltage-dependent activation of Kv4.2 channels provides a critical mechanism for regulating postsynaptic excitability. A number of voltage-dependent potassium channels are not expressed early in developing brain; however our pilot studies show that Kv4.2 channels are expressed at adult levels in immature brain. Thus, we hypothesize that the potassium channel Kv4.2 is expressed early in development and may be critical for dampening excitability in the immature brain. We propose the following aims: Aim 1: Investigation of the role of Kv4.2 channels in the regulation of excitability in the immature brain. We will evaluate expression levels and localization of Kv4.2 channel subunits in immature compared with adult mice. To assess the role of Kv4.2 channels in seizure susceptibility in immature brain we will perform convulsant stimulation in Kv4.2 knockout compared with heterozygote and wildtype mice. Aim 2: Investigation of the role of Kv4.2 channels in the development of long-term changes after early-life seizures. We will evaluate whether early-life status epilepticus leads to more profound long-term alterations in Kv4.2 knockout compared to wildtype and heterozygous mice. Long-term parameters that we will monitor are development of spontaneous seizures, neuroanatomical changes in hippocampus, and spatial learning deficits. The overall goal of this proposal to elucidate candidate mechanisms involved in regulating excitability and seizure susceptibility in immature brain and the long-term consequences of early-life status epilepticus. Relevance: Status epilepticus (uncontrollable continuous seizures) is one of the most common diagnoses for children transported to the Pediatric Intensive Care Units at a number of major children's hospitals and is associated with serious long-term consequences. Our studies are anticipated to provide insights into the mechanisms involved in regulating seizure susceptibility and status epilepticus in the developing brain and thereby may identify novel candidate targets for therapeutics in childhood epilepsy. [unreadable] [unreadable] [unreadable]

? DESCRIPTION (provided by applicant): One of the most significant consequences of developmental epilepsy is the long-term effect on behavior in children. Children who have epilepsy early in life have a higher rate of mental retardation, learning disabilities, and share a high comorbidity with autism. Mutations in the mammalian target of rapamycin (mTOR) signaling pathway are associated with higher rate of epilepsy, autism, and cognitive impairments. Therefore, abnormal activation of the mTOR signaling pathway may be an important mechanism underlying the behavioral outcomes of developmental epilepsy. The long-term goal is to identify the molecular correlates for the social behavior and other behavioral abnormalities that occur after early-life seizures and to develop therapeutic targets to treat thes behavioral abnormalities. This hypothesis has been formulated on pilot data that show a link between early-life seizures and the development of social behavior deficits in a mouse model of epilepsy. These mice demonstrate deficits in learning and memory and have upregulation of mTOR pathway signaling in the hippocampus. Guided by the pilot data presented in this proposal and the hypothesis that seizures induced at different developmental periods induce autistic-like behavioral outcomes and correlated changes in the mTOR signaling pathway, this proposal will involve the following two aims: 1) Identify the autism-like behavioral deficits and deficits in learning and memory in mice that had status epilepticus or multiple seizures during early-life or in adulthood. 2) Identify the mTOR signaling proteins and synaptic proteins that are altered in mice that had status epilepticus or multiple seizures during early-life or in adulthood. The approach is innovative because it seeks to examine the wider behavioral spectrum of the behavioral consequences due to seizures using two seizure models. The research proposed will also examine a pathway that has shown great promise to reduce/eliminate seizures but has received less attention in terms of behavioral consequences after seizures. We will also examine the pre-and postsynaptic changes that occur with aberrant mTOR activation. The proposed research is significant because it will be the first step in a continuum of research that will systematically identify the autistic- like behavioral changes and alterations in the mTOR signaling pathway that occur after seizures. It is the ultimate goal of this proposal to provide possible pharmacological treatments for the behavioral and molecular alterations in individuals with autism and epilepsy. Furthermore, the work outlined in this proposal will provide research opportunities for undergraduates to engage in hands-on biomedical research that will provide insights into the relationship between epilepsy and autism.

One of the most significant consequences of developmental epilepsy is the long-term effect on behavior. Children who have epilepsy have a higher rate of learning disabilities and share a high comorbidity with autism. Mutations in the mammalian target of rapamycin (mTOR) signaling pathway and fragile x mental retardation protein (FMRP) are associated with higher rate of epilepsy, autism, and cognitive impairments. Therefore, abnormal activation of mTOR and FMRP may be an important mechanism underlying the behavioral outcomes of developmental epilepsy and autism. The long-term goal is to identify the molecular correlates for the social behavior and other behavioral abnormalities that occur after early-life seizures in a monogenic model of autism and to develop therapeutic targets to treat these behavioral abnormalities. This hypothesis has been formulated on pilot data that show a link between early-life seizures and the development of social behavior deficits in a monogenic mouse model of epilepsy. These mice demonstrate deficits in learning and memory and have upregulation of mTOR signaling in the hippocampus. Guided by the pilot data presented in this proposal and the hypothesis that seizures during early development in mice with deletion of FMR1 will have autistic-like behavioral outcomes and correlated changes in the mTOR signaling pathway and synaptodendritic alterations, this proposal will involve the following two aims.1) Identify the autism-like behavioral deficits and deficits in learning and memory in FMR1 wildtype, hemizygous, and knockout mice that had status epilepticus (SE) or multiple seizures during early-life. 2) Identify the mTOR signaling proteins and synaptic proteins that are altered in FMR1 wildtype, hemizygous, and knockout mice that had a single event of SE or multiple seizures during early-life. We will examine these changes in male (wildtype and knockout) and female mice (wildtype, hemizygous, and homozygous). The approach is innovative because will be the first step in a continuum of research that will systematically examine whether superimposing seizures on a monogenic condition leads to aberrant alterations in synaptodendritic changes. The research proposed will also examine a pathway that has shown great promise to reduce/eliminate seizures but has received less attention in terms of behavioral consequences after seizures. We will also examine the pre-and postsynaptic changes that occur with aberrant mTOR activation. The proposed research is significant because we will compare the effect of seizures induced in early development in a monogenic model of ASD and to examine cognitive deficits and autism behavioral features: social, repetitive, and communication. The ultimate goal of this proposal is to provide possible pharmacological treatments for the behavioral and molecular alterations in individuals with autism and epilepsy. Furthermore, the work outlined in this proposal will provide research opportunities for undergraduates to engage in hands-on biomedical research that will provide insights into the relationship between epilepsy and autism.