Project Five: PACAP-CRF in postmortem human PTSD

The goal of Project 5 is to elucidate relationships among PACAP and CRF signaling, circadian rhythm regulation, and sex differences in the pathophysiology of PTSD from postmortem human brain.

Compelling evidence indicates that CRF and PACAP, as well as their interactions together, make critical contributions to stress responses, anxiety, circadian rhythm regulation, and the pathophysiological mechanisms of post-traumatic stress disorder (PTSD). The underlying neural circuitry involved is poorly understood, but important clues point to the bed nucleus of the stria terminalis (BNST), amygdala (AMG), dorsal anterior cingulate gyrus (dACG), and the hypothalamus (HPTh) as critical regulators of these functions. Current evidence indicates that CRF and PACAP mechanisms that contribute to PTSD may be sex-specific, raising the possibility that the underlying brain changes and potential therapeutic targets may differ in males and females. Current and preliminary data suggest that PACAP signaling may directly affect CRF expressing cells and that circadian expression of PACAP and its cognate receptor PAC1R, and their subsequent regulation of CRF systems, may vary during the course of the day. Such variations may potentially contribute to disruptions of sleep/wake cycles associated with DSM-defined illnesses including PTSD, major depression, and anxiety disorders. Surprisingly, virtually no information is available on cell-level expression of CRF and PACAP signaling pathways in the human AMG, BNST, dACG and HPTh, their relationships to circadian rhythms, and the involvement of CRF/PACAP interactions in the neuropathology of PTSD.

Our overarching hypothesis is that abnormalities affecting CRF/PACAP pathways in the BNST, AMG and dACG and HPTh contribute to the pathology of PTSD.