Chronic Stress and Abdominal Pain: Novel Mechanisms Chronic stress activates the Hypothalamic-Pituitary-Adrenal (HPA) axis and is a known inducer of abdominal pain. Recent reports indicate that chronic psychological stress causes changes in epigenetic regulation of gene function in CNS regions associated with memory and mood. Epigenetics refers to stable and/or heritable changes in gene function without changes in the DNA sequence via DNA methylation, histone modification and chromatin remodeling. The field of epigenetics has emerged rapidly in the past decade based on seminal studies demonstrating genome-wide distribution of methylation and acetylation sites in primary cells and human cell lines. It is unknown whether chronic stress regulates peripheral pain pathways via epigenetic mechanisms. The endovanilloid transient receptor potential (TRP) pathway plays a pivotal role in pain transmission and the TRPV1 receptor is known to be regulated by endocannabinoids (CB) acting on CB1 receptors which inhibit TRPV1 function. Chronic stress down-regulates the function of the CB pathway resulting in up-regulation of TRPV1 receptor function and abdominal pain. We will examine the hypothesis that chronic stress induces visceral pain via epigenetic regulation of CB1 and TRPV1 receptors in a region- and cel- specific manner in dorsal root ganglion (DRG) neurons innervating pelvic organs but not the somatosensory distribution to the lower extremities. Specifically, our preliminary data support two highly novel hypotheses: 1. Chronic intermittent stress promotes DNMT1-mediated methylation of glucocorticoid receptor (GR) promoter sites resulting in decreased GR expression that is linked to reduced levels and function of the anti-nociceptive endocannabinoid CB1 receptor, and enhances histone acetylation linked to increased expression and function of the pro-nociceptive endovanilloid TRPV1 receptor in dorsal root ganglion (DRG) neurons;and 2. Chronic stress-induced, corticosterone (CORT)-mediated epigenetic changes are region- and cell-specific, and """"""""hardwired"""""""" to nociceptive DRGs innervating the GI tract (colon) vs. somatosensory (sciatic nerve) distribution. The hardwired expression pattern predisposes nociceptive neurons innervating the GI tract to hyperalgesia in response to colorectal distension in the setting of chronic intermittent stress. These studies will include the application of cuttin-edge methods to identify putative regulatory CpG methylation sites at the promoters of stress response genes and chromatin immunoprecipitation (ChIP) analysis of relevant histone modification targets. The subpopulation of nociceptive neurons will be identified using both immunohistochemical markers with retrograde labeling and laser capture microscopy to harvest distinct populations of DRG neurons in conjunction with quantitative single-cell PCR of relevant targets. Confirmation of the role of specific receptors and signal transduction pathways to the changes observed in CB and TRP pathways will be confirmed using targeted delivery of gene silencing (si-RNA) reagents in situ and correlation of these interventions with behavior, e.g. visceral motor response to colorectal distension. We will also examine whether the formation of CB1-TRPV1 receptor complexes plays a role in stress-associated visceral hyperalgesia in DRG neurons and transfected cells using FRET/TIRF microscopy and electrophysiological recordings. Clarifying the mechanisms underlying epigenetic regulation of chronic stress-induced visceral pain will have a significant impact on our understanding of how pain pathways are regulated and, likely, the management of functional pain disorders affecting the GI tract.

Public Health Relevance

The observation that there is an association between abnormal levels of stress and increased perception of abdominal pain is a well described and common complaint in clinical medicine. The pathways and mechanisms that underlie this process are poorly understood. The proposed studies will explore the highly novel hypothesis that changes in epigenetic regulation of peripheral pain pathways play a significant role in the enhanced perception of abdominal pain reported in the setting of chronic stress. The proposed studies will have a significant impact on our understanding of how pain pathways are regulated and the management of functional pain disorders affecting the GI tract.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
Project #
Application #
Study Section
Clinical, Integrative and Molecular Gastroenterology Study Section (CIMG)
Program Officer
Hamilton, Frank A
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Michigan Ann Arbor
Internal Medicine/Medicine
Schools of Medicine
Ann Arbor
United States
Zip Code
Fourie, Nicolaas H; Wang, Dan; Abey, Sarah K et al. (2017) Structural and functional alterations in the colonic microbiome of the rat in a model of stress induced irritable bowel syndrome. Gut Microbes 8:33-45
Sharkey, Keith A; Wiley, John W (2016) The Role of the Endocannabinoid System in the Brain-Gut Axis. Gastroenterology 151:252-66
Fourie, Nicolaas H; Peace, Ralph M; Abey, Sarah K et al. (2016) Perturbations of Circulating miRNAs in Irritable Bowel Syndrome Detected Using a Multiplexed High-throughput Gene Expression Platform. J Vis Exp :
Wiley, J W; Higgins, G A; Athey, B D (2016) Stress and glucocorticoid receptor transcriptional programming in time and space: Implications for the brain-gut axis. Neurogastroenterol Motil 28:12-25
Chang, Lin; Heitkemper, Margaret M; Wiley, John W et al. (2016) 2015 James W. Freston Single Topic Conference: A Renaissance in the Understanding and Management of Irritable Bowel Syndrome. Gastroenterology 151:e1-8
Hong, Shuangsong; Zheng, Gen; Wiley, John W (2015) Epigenetic regulation of genes that modulate chronic stress-induced visceral pain in the peripheral nervous system. Gastroenterology 148:148-157.e7
Zheng, Gen; Hong, Shuangsong; Hayes, John M et al. (2015) Chronic stress and peripheral pain: Evidence for distinct, region-specific changes in visceral and somatosensory pain regulatory pathways. Exp Neurol 273:301-11
Zheng, G; Wu, S-P; Hu, Y et al. (2013) Corticosterone mediates stress-related increased intestinal permeability in a region-specific manner. Neurogastroenterol Motil 25:e127-39