PROJECT SUMMARY
Temporal lobe epilepsy (TLE) is a leading cause of seizure disorders in adults and is associated with high risk
of memory deficits that can negatively impact day-to-day functioning and quality of life. Memory deficits are most
prevalent in those with pharmacoresistant mesial TLE and hippocampal sclerosis (MTLE-HS). However, a large
subset of patients with MTLE-HS paradoxically have intact memory performance, even with histopathological
evidence of marked hippocampal cell loss. Despite the high prevalence of memory impairment in patients with
TLE, very little is known about the underlying pathophysiological etiologies of such memory dysfunction and
there are no predictive biomarkers. Our long-term objectives are to identify peripheral biomarkers and to develop
individualized prognostication models for memory impairment in adults with TLE, which will aid the development
of evidence-based clinical trials to treat or prevent memory impairment in TLE. Previously, we identified genes
and proteins associated with important neurological functions, including processes essential for new memory
formation and implicated in neurodegenerative diseases. These genes and proteins are overexpressed in the
temporal lobe of patients with TLE and impaired memory compared to those with intact memory, despite the same
pathological substrate and disease severity.
In this proposal, we will identify molecular biomarkers for episodic memory dysfunction in TLE by performing
deep molecular profiling of a well-matched and carefully clinically-phenotyped prospective series of patients with
language-dominant MTLE-HS. Guided by our strong preliminary data, we propose the following specific aims:
Aim 1) to identify regional differences in transcript and protein expression in hippocampal and temporal
neocortical tissues between patients with and without episodic memory impairment; Aim 2) to ascertain cell-type-
specific differences in RNA expression in temporal lobe tissues between patients with and without memory
impairment; and Aim 3) to identify peripheral blood biomarkers for episodic memory impairment in TLE through
integrative analyses. The proposed research is innovative because we will broadly and deeply characterize the
brain transcriptome and targeted proteome in TLE, which has not been investigated previously, using resources
and expertise that are unique to the Cleveland Clinic Epilepsy Center, one of the largest surgical epilepsy centers
in the US. The impact of this project includes 1) the elucidation of molecular underpinnings for episodic memory
impairment in pharmacoresistant TLE and 2) the identification of predictive peripheral biomarkers of memory
dysfunction in TLE. These are crucial first steps in the effort to identify measurable markers and mechanisms of memory
impairment in TLE. The ultimate future goal is the development of personalized prognostication models and evidence-
based clinical trials to treat or prevent memory impairment in TLE, in order to improve day-to-day functioning
and quality of life. In addition, our findings will have important implications for other neurological disorders
associated with memory impairment due to predictably overlapping biological mechanisms.