TARPγ8-Dependent Allosteric Modulation of AMPA Receptor Function
Supervisor Name
Mohammad Qneibi
Supervisor Email
mqneibi@najah.edu
University
An-Najah National University
Research field
Medical Sciences
Bio
Dr. Mohammad Qneibi earned a doctorate in neurochemistry from the State University of New York, Albany. Dr. Qneibi then pursued postdoctoral training at Yale University School of Medicine and Hebrew University-Hadassah School of Medicine. He joined the faculty at An-Najah University in 2016. He is the Director/Founder of the Center for Neuroscience Research and an Associate Professor in the Biomedical Sciences Department. Dr. Qneibi's research focuses on membrane proteins on the cell's surface. Extracellular signals, such as neurotransmitters, hormones, and sensory stimuli, regulate the activity of all cells. These signals are transmitted into the cell's interior via membrane receptor proteins. The primary research interest in my lab is understanding the mechanisms by which these membrane proteins facilitate signal transmission and transduction. He is particularly interested in the kinetic and molecular mechanisms of protein function, as well as how protein-protein and protein-drug interactions influence structure and function. In addition, he is working to develop more effective inhibitors/potentiators to regulate membrane protein function. In the long run, he expects his research will provide a better understanding of the mechanisms of action of these molecular machines and valuable insights for developing molecular devices that can be used as diagnostic and detection tools for disease treatment and the study of signal transduction pathways. Dr. Qneibi's research takes an interdisciplinary approach, combining electrophysiology, neuroscience, molecular biology, biochemical and biophysical chemistry, and membrane protein-specific rapid kinetic techniques.
Description
This project investigates the pharmacological effects of eight dibenzobarrelene-derived compounds, designated ND-1 to ND-8, on AMPA receptors. These receptors mediate much of the rapid excitatory signaling in the central nervous system, and their activity is influenced by auxiliary proteins such as TARPγ8. Understanding how new compounds affect AMPA receptors requires examining both their ability to inhibit receptor currents and their effects on the timing of receptor activation, desensitization, and recovery. The study therefore aims to characterize the ND compounds and determine how receptor composition and the presence of TARPγ8 influence their activity. The experimental component uses HEK293T cells expressing GluA2 or GluA2/GluA3 AMPA receptors, with and without TARPγ8, creating four receptor configurations for comparison. Whole-cell patch-clamp recordings measure the electrical currents generated when these receptors are stimulated with glutamate. Each compound is tested across a range of concentrations to establish concentration-response relationships, estimate its inhibitory potency, and quantify its effect on peak-current amplitude. Perampanel serves as the reference inhibitor, allowing the effects of the new compounds to be evaluated against an established AMPA-receptor modulator. Beyond measuring current inhibition, the study examines how the compounds alter receptor kinetics. Desensitization measurements assess how rapidly receptor responses decline during continued glutamate exposure, while deactivation measurements assess how rapidly currents decay after glutamate is removed. Paired-pulse experiments examine recovery from desensitization, determining how quickly receptors regain their ability to respond to a subsequent stimulus. These measurements help distinguish compounds that primarily reduce current amplitude from those that also substantially alter the duration and recovery of receptor responses. Additional experiments assess receptor selectivity by comparing activity at AMPA receptors with activity at kainate and NMDA receptors. Potential off-target effects are also examined through hERG-channel testing. The computational component uses molecular docking to predict how the ND compounds may interact with the perampanel-associated allosteric pocket. Predicted binding poses, interacting residues, and docking scores are examined alongside the experimental findings to explore possible structural explanations for differences between compounds. The project integrates electrophysiological measurements, concentration-response and kinetic modeling, statistical comparisons, and molecular docking to characterize the compounds’ effects across receptor configurations. Particular attention is given to identifying informative analogues, understanding the influence of TARPγ8, and distinguishing inhibitory potency from effects on receptor kinetics and recovery.