Corticotropin-releasing hormone and inflammation

Area of Science:

• Neuroendocrinology
• Immunology
• Pharmacology

Background:

• Corticotropin-releasing hormone (CRH) regulates the stress response via the hypothalamic-pituitary-adrenal (HPA) axis.
• CRH influences the immune system indirectly through glucocorticoids and the sympathetic nervous system.
• Cytokines like TNF-alpha, IL-1, and IL-6 stimulate CRH secretion during inflammation.

Purpose of the Study:

• To investigate the direct role of CRH in inflammatory immune processes in vivo.
• To explore CRH and its receptors in various experimental and human inflammatory conditions.
• To assess the therapeutic potential of CRH receptor antagonists.

Main Methods:

• Systemic CRH immunoneutralization in carrageenin-induced inflammation models.
• Studies on streptococcal cell wall polysaccharide- and adjuvant-induced arthritis, and peptide R16-induced uveitis.
• Analysis of CRH, CRH mRNA, and CRH receptors in human inflammatory diseases (rheumatoid arthritis, Hashimoto thyroiditis, ulcerative colitis).
• Administration of antalarmin, a CRH receptor antagonist, in vivo.

Main Results:

• Inflamed tissues showed high levels of immunoreactive (IR) CRH, CRH mRNA, and CRH receptors, particularly in mast cells.
• Peripheral nervous system, including sympathetic neurons, contributes to CRH production at inflammatory sites.
• Antalarmin selectively antagonized CRH at CRHR1 receptors and inhibited CRH-stimulated ACTH release and inflammation in vivo.

Conclusions:

• CRH plays a direct role in inflammatory immune responses, acting on immune cells like mast cells.
• CRH production by immune cells and the peripheral nervous system contributes to inflammation.
• CRH receptor antagonists, such as antalarmin, offer a promising therapeutic strategy for inflammatory conditions mediated by CRHR1.