Effects of selective type I and II adrenal steroid agonists on immune cell distribution.
ABSTRACT Adrenal steroids exert their effects through two distinct adrenal steroid receptor subtypes; the high affinity type I, or mineralocorticoid, receptor and the lower affinity type II, or glucocorticoid, receptor. Adrenal steroids have well known effects on immune cell distribution, and although both type I and II receptors are expressed in immune cells and tissues, few data exist on the relative effects mediated through these two receptor subtypes. Accordingly, we administered selective type I and II adrenal steroid receptor agonists to young adult male Sprague-Dawley rats for 7 days and then measured immune cell distribution in the peripheral blood and spleen. Results were compared with those of similar studies using the naturally occurring glucocorticoid of the rat, corticosterone, which binds both type I and II receptors. The majority of the well characterized effects of adrenal steroids on peripheral blood immune cells (increased neutrophils and decreased lymphocytes and monocytes) were reproduced by the type II receptor agonist, RU28362. RU28362 decreased the numbers of all lymphocyte subsets [T-cells, B-cells, and natural killer (NK) cells] to very low absolute levels. The largest relative decrease (i.e. in percentage) was seen in B-cells, whereas NK cells exhibited the least relative decrease and actually showed a 2-fold increase in relative percentage during RU28362 treatment. Similar to RU28362, the type I receptor agonist, aldosterone, significantly reduced the number of lymphocytes and monocytes. In contrast to RU28362, however, aldosterone significantly decreased the number of neutrophils. Moreover, aldosterone decreased the number of T-helper cells and NK cells, while having no effect on the number of B-cells or T-suppressor/cytotoxic cells. Corticosterone at physiologically relevant concentrations had potent effects on immune cell distribution, which were indistinguishable from those of the type II receptor agonist, RU28362. Taken together, these results indicate that effects of adrenal steroids on immune cell distribution are dependent on the receptor subtype involved as well as the specific cell type targeted. These factors allow for varied and complex effects of adrenal steroids on the immune system under physiological conditions.
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ABSTRACT: The glucocorticoid RU 28362 was employed to identify glucocorticoid receptors in the olfactory mucosa of the guinea-pig. Results demonstrate significant binding of RU 28362 and suggest that the olfactory mucosa is a target site for glucocorticoid action.Chemical Senses 07/1997; 22(3):313-9. DOI:10.1093/chemse/22.3.313 · 3.28 Impact Factor
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ABSTRACT: Delayed-type hypersensitivity (DTH) reactions represent cell-mediated immune responses that exert important immunoprotective (resistance to viruses, bacteria, and fungi) or immunopathological (allergic or autoimmune hypersensitivity) effects. We initially utilized the skin DTH response as an experimental in vivo model to study neuro-endocrine-immune interactions in rodents. We hypothesized that just as an acute stress response prepares the cardiovascular and musculoskeletal systems for fight or flight, it may also prepare the immune system for challenges which may be imposed by a stressor. The skin DTH model allowed us to examine the effects of stress at the time of primary and secondary exposure to antigen. Studies showed that acute (2h) stress experienced before primary or secondary antigen exposure induces a significant enhancement of skin DTH. Importantly, this enhancement involved innate as well as adaptive immune mechanisms. Adrenalectomy eliminated the stress-induced enhancement of DTH. Acute administration of physiological (stress) concentrations of corticosterone and/or epinephrine to adrenalectomized animals enhanced skin DTH. Compared with controls, DTH sites from acutely stressed or hormone-injected animals showed significantly greater erythema and induration, numbers of infiltrating leukocytes, and levels of cytokine gene expression. In contrast to acute stress, chronic stress was immunosuppressive. Chronic exposure to corticosterone, or acute exposure to dexamethasone significantly suppressed skin DTH. These results suggest that during acute stress, endogenous stress hormones enhance skin immunity by increasing leukocyte trafficking and cytokine gene expression at the site of antigen entry. While these results are discussed from a mechanistic and clinical relevance perspective, it is acknowledged that much work remains to be done to elucidate the precise mechanisms mediating these bi-directional effects of stress and stress hormones and their clinical ramifications.Brain Behavior and Immunity 01/2003; 16(6):785-98. DOI:10.1016/S0889-1591(02)00036-3 · 6.13 Impact Factor
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ABSTRACT: : It is widely believed that stress suppresses immune function and increases susceptibility to infections and cancer. Paradoxically, stress is also known to exacerbate allergic, autoimmune, and inflammatory diseases. These observations suggest that stress may have bidirectional effects on immune function, being immunosuppressive in some instances and immunoenhancing in others. It has recently been shown that in contrast to chronic stress that suppresses or dysregulates immune function, acute stress can be immunoenhancing. Acute stress enhances dendritic cell, neutrophil, macrophage, and lymphocyte trafficking, maturation, and function and has been shown to augment innate and adaptive immune responses. Acute stress experienced prior to novel antigen exposure enhances innate immunity and memory T-cell formation and results in a significant and long-lasting immunoenhancement. Acute stress experienced during antigen reexposure enhances secondary/adaptive immune responses. Therefore, depending on the conditions of immune activation and the immunizing antigen, acute stress may enhance the acquisition and expression of immunoprotection or immunopathology. In contrast, chronic stress dysregulates innate and adaptive immune responses by changing the type 1-type 2 cytokine balance and suppresses immunity by decreasing leukocyte numbers, trafficking, and function. Chronic stress also increases susceptibility to skin cancer by suppressing type 1 cytokines and protective T cells while increasing suppressor T-cell function. We have suggested that the adaptive purpose of a physiologic stress response may be to promote survival, with stress hormones and neurotransmitters serving as beacons that prepare the immune system for potential challenges (eg, wounding or infection) perceived by the brain (eg, detection of an attacker). However, this system may exacerbate immunopathology if the enhanced immune response is directed against innocuous or self-antigens or dysregulated following prolonged activation, as seen during chronic stress. In view of the ubiquitous nature of stress and its significant effects on immunoprotection and immunopathology, it is important to further elucidate the mechanisms mediating stress-immune interactions and to meaningfully translate findings from bench to bedside.Allergy Asthma and Clinical Immunology 03/2008; 4(1):2-11. DOI:10.1186/1710-1492-4-1-2