Melatonin as potential inducer of Th17 cell differentiation

Bioinformatics and Network Pharmacology Identify the Therapeutic Role and Potential Mechanism of Melatonin in AD and Rosacea

Rosacea is significantly associated with dementia, particularly Alzheimer’s disease (AD). However, the common underlying molecular mechanism connecting these two diseases remains limited. This study aimed to reveal the common molecular regulatory networks and identify the potential therapeutic drugs for rosacea and AD. There were 747 overlapped DEGs (ol-DEGs) that were detected in AD and rosacea, enriched in inflammation-, metabolism-, and apoptosis-related pathways. Using the TF regulatory network analysis, 37 common TFs and target genes were identified as hub genes. They were used to predict the therapeutic drugs for rosacea and AD using the DGIdb/CMap database. Among the 113 predicted drugs, melatonin (MLT) was co-associated with both RORA and IFN-γ in AD and rosacea. Subsequently, network pharmacology analysis identified 19 pharmacological targets of MLT and demonstrated that MLT could help in treating AD/rosacea partly by modulating inflammatory and vascular signaling pathways. Finally, we verified the therapeutic role and mechanism of MLT on rosacea in vivo and in vitro. We found that MLT treatment significantly improved rosacea-like skin lesion by reducing keratinocyte-mediated inflammatory cytokine secretion and repressing the migration of HUVEC cells. In conclusion, this study contributes to common pathologies shared by rosacea and AD and identified MLT as an effective treatment strategy for rosacea and AD via regulating inflammation and angiogenesis.

Overexpression of ASMT likely enhances the resistance of transgenic sheep to brucellosis by influencing immune-related signaling pathways and gut microbiota

Melatonin is a pleiotropic molecule with a variety of biological functions, which include its immunoregulatory action in mammals. Brucellosis is a worldwide endemic zoonotic disease caused by the Brucella, which not only causes huge economic losses for the livestock industry but also impacts human health. To target this problem, in current study, two marker-free transgenic sheep overexpressing melatonin synthetic enzyme ASMT (acetylserotonin O-methyltransferase) gene were generated and these melatonin enrich transgenic sheep were challenged by Brucella infection. The results showed that the serum melatonin concentration was significantly higher in transgenic sheep than that of wild type (726.92 ± 70.6074 vs 263.10 ± 34.60 pg/mL, P < .05). Brucella challenge test showed that two thirds (4/6) of the wild-type sheep had brucellosis, while none of the transgenic sheep were infected. Whole-blood RNA-seq results showed that differential expression genes (DEGs) were significantly enriched in natural killer cell-mediated cytotoxicity, phagosome, antigen processing, and presentation signaling pathways in overexpression sheep. The DEGs of toll-like receptors (TLRs) and NOD-like receptors (NLRs) families were verified by qPCR and it showed that TLR1, TLR2, TLR7, CD14, NAIP, and CXCL8 expression levels in overexpression sheep were significantly higher and NLRP1, NLRP3, and TNF expression levels were significantly lower than those of wild type. The rectal feces were subjected to 16S rDNA amplicon sequencing, and the microbial functional analysis showed that the transgenic sheep had significantly lower abundance of microbial genes related to infectious diseases compared to the wild type, indicating overexpression animals are likely more resistant to infectious diseases than wild type. Furthermore, exogenous melatonin treatment relieved brucellosis inflammation by upregulating anti-inflammatory cytokines IL-4 and downregulating pro-inflammatory IL-2, IL-6, and IFN-γ. Our preliminary results provide an informative reference for the study of the relationship between melatonin and brucellosis.

Association of Melatonin Pathway Gene's Single-Nucleotide Polymorphisms with Systemic Lupus Erythematosus in a Chinese Population

Objectives

This study was to investigate the association of melatonin (MTN) pathway gene's single-nucleotide polymorphisms (SNPs) with susceptibility to systemic lupus erythematosus (SLE).

Methods

We recruited 495 SLE patients and 493 healthy controls, 11 tag SNPs in MTN receptor 1a (MTNR1a), MTNR1b, and arylalkylamine N-acetyltransferase (AANAT) genes were genotyped and analyzed. Serum MTN concentration was determined by enzyme-linked immunosorbent assay (ELISA) kits.

Results

Two SNPs of AANAT gene (rs8150 and rs3760138) associated with the risk of SLE; CC carriers of rs8150 had a lower risk as compared to GG (OR = 0.537, 95% CI: 0.361, 0.799), whereas GG carrier in rs3760138 had an increased risk (OR = 1.823, 95% CI: 1.154, 2.880) compared to TT. However, we did not find any genetic association between the other nine SNPs with SLE risk. Case-only analysis showed associations of rs2165667 and rs1562444 with arthritis, rs10830962 with malar rash, rs3760138 with immunological abnormality, and rs8150 with hematological abnormality. Furthermore, a significant difference between plasma MTN levels with different genotypes of rs1562444 was observed. Haplotype analyses revealed that haplotype of CCTAT, CTAGT, and GGG was significantly associated with the increased risk in SLE susceptibility, but TCTAT and CTG appeared to be a protective haplotype.

Conclusions

The present study supported the genetic association of MTN pathway genes with SLE susceptibility and specific clinical manifestations, suggesting the potential role of MTN pathway genes in the pathogenesis and development of SLE.

Pleiotropic roles of melatonin in endometriosis, recurrent spontaneous abortion, and polycystic ovary syndrome

Melatonin is a neurohormone synthesized from the aromatic amino acid tryptophan mainly by the pineal gland of mammals. Melatonin acts as a broad-spectrum antioxidant, powerful free radical scavenger, anti-inflammatory agent, anticarcinogenic factor, sleep inducer and regulator of the circadian rhythm, and potential immunoregulator. Melatonin and reproductive system are interrelated under both physiological and pathological conditions. Oxidative stress, inflammation, and immune dysregulation are associated with the pathogenesis of the female reproductive system which causes endometriosis (EMS), recurrent spontaneous abortion (RSA), and polycystic ovary syndrome (PCOS). Accumulating studies have indicated that melatonin plays pleiotropic and essential roles in these obstetrical and gynecological disorders and would be a candidate therapeutic drug to regulate inflammation and immune function and protect special cells or organs. Here, we systematically review the pleiotropic roles of melatonin in EMS, RSA, and PCOS to explore its pathological implications and treatment potential.

[Melatonin as an inducing factor for multiple sclerosis]

Melatonin is one of the most multifunctional regulators in the organism. It plays a key role in the control of nerve, endocrine, and immune systems. Due to hormone neuroprotective activity, the possibility is now discussed on its clinical usage in treating neurodegenerative diseases, including multiple sclerosis. At the same time, melatonin is an effective regulator of immune reactions, in part, the reactions toward autoantigens. In this respect, the subset ofT lymphocytes producing IL-17 (Th17) is of special interest. As the Th17 subset plays a key role iri multiple sclerosis pathogenesis, the immunomodulating hormone effects toward Th17, may, in theory, nullify its positive neuroprotective activity.

Melatonin antiproliferative effects require active mitochondrial function in embryonal carcinoma cells

Although melatonin oncostatic and cytotoxic effects have been described in different types of cancer cells, the specific mechanisms leading to its antitumoral effects and their metabolic context specificity are still not completely understood. Here, we evaluated the effects of melatonin in P19 embryonal carcinoma stem cells (CSCs) and in their differentiated counterparts, cultured in either high glucose medium or in a galactose (glucose-free) medium which leads to glycolytic suppression and increased mitochondrial metabolism. We found that highly glycolytic P19 CSCs were less susceptible to melatonin antitumoral effects while cell populations relying on oxidative metabolism for ATP production were more affected. The observed antiproliferative action of melatonin was associated with an arrest at S-phase, decreased oxygen consumption, down-regulation of BCL-2 expression and an increase in oxidative stress culminating with caspase-3-independent cell death. Interestingly, the combined treatment of melatonin and dichloroacetate had a synergistic effect in cells grown in the galactose medium and resulted in an inhibitory effect in the highly resistant P19 CSCs. Melatonin appears to exert its antiproliferative activity in P19 carcinoma cells through a mitochondrially-mediated action which in turn allows the amplification of the effects of dichloroacetate, even in cells with a more glycolytic phenotype.

Interleukin-17, oxidative stress, and inflammation: role of melatonin during Trypanosoma cruzi infection

Although the exact etiology of Chagas' disease remains unknown, the inflammatory process and oxidative stress are believed to be the main contributors to the dysfunction and pathogenesis during chronic Trypanosoma cruzi infection. Our hypothesis is that melatonin administered for 2 months daily could modulate the oxidative stress and the inflammatory response during the chronic infection. Flow cytometric analysis of macrophages and antigen-presenting cells (APC), expression of RT1B as well as LFA-1 and MCP-1 in CD4(+) and CD8(+) T cells and levels of interleukin-17A were assessed. The oxidative stress was evaluated through lipid peroxidation (LPO) analysis on the plasma of thiobarbituric acid-reactive substances (TBARS) and nitric oxide production. Decreased concentrations of nitrite and TBARS were found in infected and melatonin-treated animals, as well as a rising trend in the production of IL-17A as compared to infected and untreated counterparts. A significant decrease was found in the percentages of CD4(+) and CD8(+) T lymphocytes MCP-1 producers for infected and melatonin-treated rats. Reduced percentage of CD8(+) T cells producing LFA-1 was observed in control and melatonin-treated animals as compared to untreated rats. The cellular response of peritoneal APC cells and macrophages significantly dropped in infected and treated animals. As an endpoint, the use of antioxidant compounds such as melatonin emerges as a new and promising approach to control the oxidative stress during the chronic Chagas' disease partially mediated through the abrogation of LPO and the prevention of the inflammatory response and can be used for further investigation on treatment trials for other infectious diseases.