The role of melatonin in the cells of the innate immunity: a review

Abstract

Melatonin is the major secretory product synthesized and secreted by the pineal gland and shows both a wide distribution within phylogenetically distant organisms from bacteria to humans and a great functional versatility. In recent years, a considerable amount of experimental evidence has accumulated showing a relationship between the nervous, endocrine, and immune systems. The molecular basis of the communication between these systems is the use of a common chemical language. In this framework, currently melatonin is considered one of the members of the neuroendocrineimmunological network. A number of in vivo and in vitro studies have documented that melatonin plays a fundamental role in neuroimmunomodulation. Based on the information published, it is clear that the majority of the present data in the literature relate to lymphocytes; thus, they have been rather thoroughly investigated, and several reviews have been published related to the mechanisms of action and the effects of melatonin on lymphocytes. However, few studies concerning the effects of melatonin on cells belonging to the innate immunity have been reported. Innate immunity provides the early line of defense against microbes and consists of both cellular and biochemical mechanisms. In this review, we have focused on the role of melatonin in the innate immunity. More specifically, we summarize the effects and action mechanisms of melatonin in the different cells that belong to or participate in the innate immunity, such as monocytes-macrophages, dendritic cells, neutrophils, eosinophils, basophils, mast cells, and natural killer cells.

A Double-Blind, Placebo-Controlled Trial Related to the Effects of Melatonin on Oxidative Stress and Inflammatory Parameters of Obese Women

“…Melatonin (N-acetyl-5-methoxytryptamine) in mammals is synthesized in several cells, tissues, and organs mainly for local utilization (autocrine and paracrine actions) and the circulating melatonin is mostly provided by the pineal gland [11,12]. It is known that melatonin is responsible for regulation of circadian rhythms, immune responses and mood, and reduces oxidative stress [13][14][15][16]. The roles of melatonin in obesity management have been studied in animal models of diet-induced obesity.…”

Melatonin: a possible link between the presence of artificial light at night and reductions in biological fitness

“…Similarly, a number of studies have found melatonin plays a fundamental role in immune-modulation, but this has been explored almost exclusively in vertebrates (for recent reviews see [71][72][73]). The immune-modulatory effect of melatonin on the adaptive vertebrate immune system is supported by the existence of specific melatonin receptors in immune organs as well as immunocompetent cells, with its role in innate immunity recently proposed [71]. This latter finding is of particular interest from the invertebrate perspective, because while invertebrates lack an adaptive immune response, their innate immune system, particularly that of the insects, is highly effective and has cellular recognition and defensive pathways that are comparable with vertebrates (for a comprehensive coverage of the discipline see [74]).…”

“…Melatonin supplementation experiments generally reveal a positive effect of melatonin on survival in both vertebrates and invertebrates [67][68][69][70]. Similarly, a number of studies have found melatonin plays a fundamental role in immune-modulation, but this has been explored almost exclusively in vertebrates (for recent reviews see [71][72][73]). The immune-modulatory effect of melatonin on the adaptive vertebrate immune system is supported by the existence of specific melatonin receptors in immune organs as well as immunocompetent cells, with its role in innate immunity recently proposed [71].…”

Melatonin and ubiquitin: what’s the connection?

“…Many of the effects of melatonin on the immune system and on inflammation also are mediated by nf-κB [74,87,88]. Melatonin reduces nf-κB binding in spleen [89].…”