240 Characterization of leukocyte glucocorticoid receptor translocation in response to physical stress

Physical stress provides an easily manipulated experimental model that allows for the study of interactions between the neuroendocrine and immune systems. Severe exercise elicits marked alterations in circulating stress hormones, causing shifts in leukocyte mobilization and function both during and after exercise. Circulating levels of glucocorticoids and their receptors are known to be altered by acute and chronic exercise. Cortisol binds to the cytosolic glucocorticoid receptors (GCRs) in leukocytes resulting in GC-mediated immunosuppression. Long-term GCRs dysfunction in leukocytes can enhance susceptibility to autoimmune and inflammatory diseases. This study examined physiological cortisol release with strenuous exercise, and measured GCR translocations in peripheral blood T lymphocytes and total leukocytes before and after intense exercise using multispectral imaging flow cytometry. Blood samples were collected before and after intense exercise from 8 healthy participants. The cytosolic levels of FITC-GCRs, GC-GCR complex nuclear (Vybrant Dye) and mitochondria (MitoTrackerRed) translocations were determined for total leukocytes (Leu) and CD3+ lymphocytes. The image-based measurement showed that there was a biphasic response in GCR translocation to the nucleus on the CD3+GCRDim lymphocytes before (88%), immediately after (36%) and 30-min (90%) after exercise. There was no change in the CD3+GCRBright lymphocytes. The GCR nuclear translocation on GCRDim Leu expressed a biphasic trend, pre (74%), immediately post (25%) and 30-min (80%) post exercise. The GCRBright Leu had shown a decreased in GCR translocation over time. It was observed that a portion of the GCRDim lymphocytes and GCRDim Leu translocated to the mitochondria after exercise stress. Our data provide insights into the pathophysiological role and mechanisms of cortisol and GCRs on immune cells under subclinical physical stress. This method is particularly important in understanding the GC-induced apoptosis via mitochondria translocation and GC-mediated immunosuppression through nuclear translocation in inflammatory diseases.