We have recently uncovered the role of a key pathway activated by ethanol exposure, which regulates changes in BK channel surface expression involved in persistent forms of alcohol tolerance. The canonical Wnt/ß-catenin pathway regulates BK channel surface expression in a protein synthesis-dependent manner. This key regulatory pathway has been the focus of intense study in the field of cancer research and thus affords us clinically tested drugs for future studies which can be applied with the novel intent of preventing and treating alcohol dependency.
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To probe the association between alcohol tolerance and learning and memory further I designed a series of experiments carried out in collaboration with Dr. Quirk’s laboratory at the Medical Science Campus of the University of Puerto Rico. Using our single episodic in-vivo ethanol exposure, after fear conditioning but prior to extinction, resulted in specific impairment of fear extinction in behavioral assays indicating there may be specific effect of alcohol on the basolateral amygdala (BLA). Studies have shown the AKT/GSK-3/ß-catenin cascade within the amygdala are genetically determined molecular correlates associated to the severity of PTSD-like symptoms. Therefore, future experiments will determine if the observed impairment in extinction learning is due to alcohol deregulation of Wnt/ß-catenin signaling in the BLA. This is the subject of my NIH-R21 grant submission in 2016. To date there are no publications associating a single episodic alcohol exposure with the development of PTSD-like symptoms. Thus, my project presents a unique insight into how less pathologic patterns of drinking behavior may impact the development of anxiety disorders after a traumatic event. These finding may provide novel approaches for clinical prevention and treatment of alcohol abuse associated disorders such as PTSD.
Experiments are underway to determine the functional activation of ß-catenin via reporter assays using both the Topflash construct with multiple TCF/LEF-binding sites in the promoter of a firefly luciferase reporter gene and the derived Fopflash construct with mutated TCF/ LEF-binding sites. These assays will help determine if ß-catenin transcriptional regulation occurs in response to EtOH and/or miRNA regulation.