ARC in Peripheral Blood EVs – A Novel Biomarker of Brain Inhibition/Excitation Imbalance in Temporal Lobe Epilepsy
Abstract number :
1.465
Submission category :
2. Translational Research / 2C. Biomarkers
Year :
2022
Submission ID :
2232967
Source :
www.aesnet.org
Presentation date :
12/3/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:28 AM
Authors :
James Castellano, MD, PhD – University of Pittsburgh; Perla Moreno Castilla, PhD – National Institute on Aging; Alexus Sieger, PA-C – University of Pittsburgh; Hallie Williams, PA-C – University of Pittsburgh; Cathy Van Every, RN – University of Pittsburgh; Alexandra Zyznewsky, NP – University of Pittsburgh; Peter Rapp, PhD – National Institute on Aging
This is a Late-Breaking abstract.
Rationale: The immediate-early gene ARC is rapidly and transiently induced following excitatory neuronal activity including maximal electroconvulsive shock treatment. ARC mRNA is selectively transcribed following patterned neuronal activity and rapidly trafficked to dendrites where it preferentially accumulates at active synapses for local translation. Arc has been detected in blood extracellular vesicles (EVs) of rats and has been shown to change with age-related cognitive impairment and hippocampal pathology. Here, we seek to test the hypotheses that there are differences in the levels of Arc contained in EV in patients with temporal lobe epilepsy compared to patients with psychogenic nonepileptic seizures (PNES).
Methods: Plasma samples from Control (PNES) and Temporal Lobe Epilepsy groups were obtained during epilepsy monitoring unit admission. Temporal lobe epilepsy diagnosis was supported by semiology, ictal and interictal electrophysiology, as well as imaging. PNES diagnosis was confirmed by capture of typical events with a non-epileptiform EEG. Samples were stored until EVs were isolated by ultracentrifugation. Two steps of centrifugation consisting in 4 h at 32,500 rpm at 4°C. Afterwards, the supernatant was decanted to allow the EV pellet to dry and pellets were resuspended to quantify Arc protein content by denaturing gel electrophoresis and Western blot. Chemiluminescent signals were quantified using a fluorescent Imager. Primary antibodies used in the current study were Arc (Santa Cruz, 17839 and Synaptic Systems, 156003), Alix (Cell Signaling, 92880S), Flotilin-1 (Cell Signaling, 18634), CD63 (Thermo Fisher Scientific, A15712), and CD9 (Thermo Fisher Scientific, 17-0098-42).
Results: Arc protein is present in circulating EVs and Peripheral Arc-EVs are increased in patients with temporal lobe epilepsy
Conclusions: These findings suggest that the levels of the synaptic protein Arc contained in EVs in peripheral blood may provide a noninvasive biomarker for disrupted inhibition/excitation imbalances in temporal lobe epilepsy.
Funding: NeuroNEXT U24NS107166; NIA Intramural Funds
Translational Research