gamma2-msh and Inflammation

The neuro-immuno-cutaneous-endocrine network is not a simple construct featuring organ systems intimately involved in the bridge between body and mind. Mind-body influences are bi-directional and the skin should be considered an active neuroimmunoendocrine interface, where effector molecules of neuropeptides act as common words used in a dynamic dialogue between brain, immune system and skin. Gamma-melanocyte stimulating hormone (gamma-MSH), one of the principal neuroimmunomodulating peptides, seems to exercise some control on the cutaneous inflammatory process, through a central action mediated by descending anti-inflammatory neural pathways and via local direct influence on inflammatory cells infiltrating the dermis, such as monocytes, macrophages and neutrophils. Gamma-MSH down-regulates the production of proinflammatory cytokines, while the production of the anti-inflammatory cytokine IL-10 is stimulated by gamma-MSH. Finally, gamma-MSH seems to regulate the expression of surface molecules in immunocompetent cells. Thus, further studies may lead to the use of gamma-MSH as an important anti-inflammatory agent in clinical dermatology.

Topics: Brain; Dermatitis; Endocrine System; gamma-MSH; Humans; Inflammation; Neuroimmunomodulation; Skin

Atherosclerosis is a chronic inflammatory disease of the arteries. The disease is initiated by endothelial dysfunction that allows the transport of leukocytes and low-density lipoprotein into the vessel wall forming atherosclerotic plaques. The melanocortin system is an endogenous peptide system that regulates, for example, energy homeostasis and cardiovascular function. Melanocortin treatment with endogenous or synthetic melanocortin peptides reduces body weight, protects the endothelium and alleviates vascular inflammation, but the long-term effects of melanocortin system activation on atheroprogression remain largely unknown. In this study, we evaluated the effects of transgenic melanocortin overexpression in a mouse model of atherosclerosis. Low-density lipoprotein receptor-deficient mice overexpressing alpha- and gamma

Topics: alpha-MSH; Animals; Aorta; Atherosclerosis; Cytokines; Diet, Western; Female; gamma-MSH; Gene Expression; Glucose Intolerance; Homeostasis; Immunohistochemistry; Inflammation; Male; Melanocortins; Mice; Mice, Knockout; Mice, Transgenic; Plaque, Atherosclerotic; Receptors, LDL; Vasoconstriction; Vasodilation

This study was aimed to investigate the mechanisms of the modulation effect of activation of spinal Mas-related gene C (MrgC) receptors on hyperalgesia induced by intraplantar (i.pl.) injection of (Tyr6)-γ2-MSH-6-12 (MSH) or complete Freund's adjuvant (CFA). Paw withdrawal latency test and immunohistochemistry were used to observe the effect of intrathecal (i.t.) administration of MSH or BAM8-22, two selective agonists of MrgC receptor, in hyperalgesia in rats. The results showed that i.t. administration of MSH inhibited acute hyperalgesic response induced by i.pl. application of MSH, while did not change thermal nociceptive threshold in naïve rats. The i.t. administration of MSH also attenuated CFA-induced inflammatory hyperalgesia. However, i.t. administration of the μ-opioid receptor (MOR) antagonist CTAP blocked the induction of delayed anti-hyperalgesia by MSH. The i.t. injection of BAM8-22 at a dose of 30 nmol evidently reduced the number of CFA-evoked nitric oxide synthase (NOS)-positive neurons and the expression of calcitonin gene-related peptide (CGRP)-immunoreactivity positive nerve fibers at L3-L5 segments of the spinal cord. These results suggest that the activation of MrgC receptor in CFA-induced inflammation reduces inflammatory hyperalgesia through inactivation of NOS neurons and down-regulation of CGRP expressions, and generates delayed but long-lasting anti-nociception through the endogenous activation of MOR via indirect mechanisms. Agonists for MrgC receptors may, therefore, represent a new class of antihyperalgesics for treating inflammatory pain because of the highly specific expression of their targets.

Topics: Animals; Down-Regulation; Freund's Adjuvant; gamma-MSH; Hyperalgesia; Inflammation; Injections, Spinal; Pain Measurement; Peptide Fragments; Rats; Receptors, G-Protein-Coupled; Spinal Cord

Central autonomic and neuroendocrine activities are important components of the host response to bacterial inflammation. We demonstrate that intravenous infusion of gamma(2)-melanocyte-stimulating hormone (gamma(2)-MSH), a potent autonomic regulating peptide, prevents lipopolysaccharide (LPS)-induced hypotension and tachycardia, and modulates the ACTH response to endotoxin. In the hypothalamic paraventricular nucleus, a major neuroendocrine and autonomic center, gamma(2)-MSH inhibits LPS-induced increases in CRF mRNA levels, but does not suppress LPS-augmented arginine vasopressin heteronuclear RNA expression. In the locus coeruleus, a brainstem noradrenergic center, gamma(2)-MSH inhibits LPS-induced increases in tyrosine hydroxylase mRNA levels. Gamma(2)-MSH inhibits LPS-induced IL-1beta gene expression in the brain, pituitary and thymus, and prevents increases in plasma NO levels. These findings reveal that gamma(2)-MSH attenuates systemic inflammatory responses to endotoxin and suggest that modulation of central autonomic and neuroendocrine activities by gamma(2)-MSH contributes to its anti-inflammatory effects.

Topics: Adrenocorticotropic Hormone; Animals; Arginine Vasopressin; Autonomic Nervous System; Bacterial Infections; Brain; Corticotropin-Releasing Hormone; gamma-MSH; Hypotension; Hypothalamo-Hypophyseal System; Inflammation; Interleukin-1; Lipopolysaccharides; Male; Nitric Oxide; Rats; Rats, Sprague-Dawley; RNA, Messenger; Tachycardia; Tyrosine 3-Monooxygenase