Melatonin-induced demethylation of antioxidant genes increases antioxidant capacity through RORα in cumulus cells of prepubertal lambs

Effects of melatonin supplementation on oxidative stress, and inflammatory biomarkers in diabetic patients with chronic kidney disease: a double-blind, randomized controlled trial

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) is a progressive illness linked to higher rates of morbidity and death. One of the main causes of CKD is diabetes mellitus (DM), and oxidative stress is essential to the disease's development. It has been demonstrated that the natural antioxidant melatonin reduces inflammation and oxidative damage in renal tissues. Given the lack of robust evidence, this double-blind clinical trial sought to investigate the effects of melatonin supplementation on oxidative stress and inflammatory markers in diabetic CKD patients.

MATERIALS AND METHODS

This trial included 41 diabetic patients with CKD (stages 3-4) from Shariati Hospital, Tehran, Iran. For ten weeks, participants were randomized to receive either a placebo or 5 mg of melatonin twice a day. Baseline characteristics, dietary intake, physical activity, and anthropometric measurements were recorded. Oxidative stress (TAC, TOS, MDA) and inflammatory markers (IL-6, hs-CRP) were measured before and after the intervention. Statistical analysis was performed using SPSS, with significance set at p < 0.05.

RESULTS

The 10-week trial was completed by 41 participants in total, and no adverse effects were noted. Dietary intake, physical activity, and anthropometric parameters did not significantly differ between the melatonin and control groups in baseline characteristics. Melatonin supplementation decreased oxidative stress and inflammatory biomarkers, including hs-CRP, MDA, TOS, and IL-6. However, these changes were not statistically significant.

CONCLUSION

Our study showed that melatonin supplementation did not significantly affect oxidative stress or inflammatory markers, including TAC, TOS, MDA, IL-6, and hs-CRP, in diabetic patients with CKD. Despite a decrement in TOS, MDA, IL-6, and hs-CRP levels after 10 weeks, this was not statistically significant. Further studies with larger sample sizes, greater dosages, and longer follow-up periods are recommended.

Effects of different Lys/Met ratios on the antioxidant capacity, tissue morphology, and fatty acid composition of subcutaneous fat in Tibetan sheep on low-protein diets: a lipidomic analysis

Introduction

This study employed lipidomics to investigate the effects of varying lysine (Lys)- to-methionine (Met) ratios on the antioxidant capacity, tissue morphology, and fatty acid composition of subcutaneous fat in Tibetan sheep fed a low-protein diet.

Methods

Ninety healthy male Tibetan sheep of similar body weight were randomly allocated into three groups. These sheep were fed a low-protein diet containing Lys/Met ratios of 1:1, 2:1, and 3:1. Ultra-High Performance Liquid Chromatography-tandem Mass Spectrometry (UHPLC-MS/MS) was employed to explore the changes in various lipid subclasses in subcutaneous adipose tissue. The expression of genes associated with adipogenesis, antioxidant capacity, and fatty acid metabolism was also examined.

Results

The results indicated that the 1:1 Lys/Met group exhibited significantly higher antioxidant capacity (glutathione peroxidase, GSH-Px), with more orderly adipocyte arrangement, uniform cell size, and a general increase in unsaturated fatty acid levels. Additionally, several lipid molecules associated with the phenotype (Antioxidant index and fatty acid content) were identified, namely, DG(38:3e) + Na, PE(17:1_22:2)-H, PI(17:0_20:3)-H, TG(33:0e) + NH4, Cer(d14:0_17:1) + H, and CL(81:13)-2H. Furthermore, the findings showed that the upregulation of PPARγ, FASN, FAD4, CPT1A, and GPX4 can enhance adipocyte differentiation and lipid accumulation, thereby improving metabolic function in subcutaneous adipose tissue via the regulation of lipid metabolism and oxidative defense mechanisms.

Discussion

In summary, this study provides a theoretical foundation for optimizing precision feeding strategies for Tibetan sheep, offering crucial data to support enhancements in production efficiency and meat quality.

Melatonin-Derived Carbon Dots with Free Radical Scavenging Property for Effective Periodontitis Treatment via the Nrf2/HO-1 Pathway

Periodontitis is a chronic inflammatory disease closely associated with reactive oxygen species (ROS) involvement. Eliminating ROS to control the periodontal microenvironment and alleviate the inflammatory response could potentially serve as an efficacious therapy for periodontitis. Melatonin (MT), renowned for its potent antioxidant and anti-inflammatory characteristics, is frequently employed as an ROS scavenger in inflammatory diseases. However, the therapeutic efficacy of MT remains unsatisfactory due to the low water solubility and poor bioavailability. Carbon dots have emerged as a promising and innovative nanomaterial with facile synthesis, environmental friendliness, and low cost. In this study, melatonin-derived carbon dots (MT-CDs) were successfully synthesized via the hydrothermal method. The MT-CDs have good water solubility and biocompatibility and feature excellent ROS-scavenging capacity without additional modification. The in vitro experiments proved that MT-CDs efficiently regulated intracellular ROS, which maintained mitochondrial homeostasis and suppressed the production of inflammatory mediators. Furthermore, findings from the mouse model of periodontitis indicated that MT-CDs significantly inhibited the deterioration of alveolar bone and reduced osteoclast activation and inflammation, thereby contributing to the regeneration of damaged tissue. In terms of the mechanism, MT-CDs may scavenge ROS, thereby preventing cellular damage and the production of inflammatory factors by regulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. The findings will offer a vital understanding of the advancement of secure and effective ROS-scavenging platforms for more biomedical applications.

Ferulic Acid Enhances Oocyte Maturation and the Subsequent Development of Bovine Oocytes

Improving the quality of oocytes matured in vitro is integral to enhancing the efficacy of in vitro embryo production. Oxidative stress is one of the primary causes of quality decline in oocytes matured in vitro. In this study, ferulic acid (FA), a natural antioxidant found in plant cell walls, was investigated to evaluate its impact on bovine oocyte maturation and subsequent embryonic development. Bovine cumulus-oocyte complexes (COCs) were treated with different concentrations of FA (0, 2.5, 5, 10, 20 μM) during in vitro maturation (IVM). Compared to the control group, supplementation with 5 μM FA significantly enhanced the maturation rates of bovine oocytes and the expansion of the cumulus cells area, as well as the subsequent cleavage and blastocyst formation rates after in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT). Furthermore, FA supplementation was observed to effectively decrease the levels of ROS in bovine oocytes and improve their mitochondrial function. Our experiments demonstrate that FA can maintain the levels of antioxidants (GSH, SOD, CAT) in oocytes, thereby alleviating the oxidative stress induced by H2O2. RT-qPCR results revealed that, after FA treatment, the relative mRNA expression levels of genes related to oocyte maturation (GDF-9 and BMP-15), cumulus cell expansion (HAS2, PTX3, CX37, and CX43), and embryo pluripotency (OCT4, SOX2, and CDX2) were significantly increased. In conclusion, these findings demonstrate that FA supplementation during bovine oocyte IVM can enhance oocyte quality and the developmental potential of subsequent embryos.

Melatonin: A Potential Regulator of DNA Methylation

The pineal gland-derived indoleamine hormone, melatonin, regulates multiple cellular processes, ranging from chronobiology, proliferation, apoptosis, and oxidative damage to pigmentation, immune regulation, and mitochondrial metabolism. While melatonin is best known as a master regulator of the circadian rhythm, previous studies also have revealed connections between circadian cycle disruption and genomic instability, including epigenetic changes in the pattern of DNA methylation. For example, melatonin secretion is associated with differential circadian gene methylation in night shift workers and the regulation of genomic methylation during embryonic development, and there is accumulating evidence that melatonin can modify DNA methylation. Since the latter one impacts cancer initiation, and also, non-malignant diseases development, and that targeting DNA methylation has become a novel intervention target in clinical therapy, this review discusses the potential role of melatonin as an under-investigated candidate epigenetic regulator, namely by modulating DNA methylation via changes in mRNA and the protein expression of DNA methyltransferases (DNMTs) and ten-eleven translocation (TET) proteins. Furthermore, since melatonin may impact changes in the DNA methylation pattern, the authors of the review suggest its possible use in combination therapy with epigenetic drugs as a new anticancer strategy.

GPX4: The hub of lipid oxidation, ferroptosis, disease and treatment

Glutathione peroxidase 4 (GPx4) moonlights as structural protein and antioxidase that powerfully inhibits lipid oxidation. In the past years, it is considered as a key regulator of ferroptosis, which takes role in the lipid and amine acid metabolism and influences the cell aging, oncogenesis, and cell death. More and more evidences show that targeting GPX4-induced ferroptosis is a promising strategy for disease therapy, especially cancer treatment. In view of these, we generalize the function of GPX4 and regulatory mechanism between GPX4 and ferroptosis, discuss its roles in the disease pathology, and focus on the recent advances of disease therapeutic potential.

TBX2 affects proliferation, apoptosis and cholesterol generation by regulating mitochondrial function and autophagy in bovine cumulus cell

BACKGROUND

T-box transcription factor 2 (TBX2) is a member of T-box gene family whose members are highly conserved in evolution and encoding genes and are involved in the regulation of developmental processes. The encoding genes play an important role in growth and development. Although TBX2 has been widely studied in cancer cell growth and development, its biological functions in bovine cumulus cells remain unclear.

OBJECTIVES

This study aimed to investigate the regulatory effects of TBX2 in bovine cumulus cells.

METHODS

TBX2 gene was knockdown with siRNA to clarify the function in cellular physiological processes. Cell proliferation and cycle changes were determined by xCELLigence cell function analyzer and flow cytometry. Mitochondrial membrane potential and autophagy were detected by fluorescent dye staining and immunofluorescence techniques. Western blot and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) were used to detect the expression changes of proliferation and autophagy-related proteins. Aadenosine triphosphate (ATP) production, glucose metabolism, and cholesterol synthesis of cumulus cells were measured by optical density and chemiluminescence analysis.

RESULTS

After inhibition of TBX2, the cell cycle was disrupted. The levels of apoptosis, ratio of light chain 3 beta II/I, and reactive oxygen species were increased. The proliferation, expansion ability, ATP production, and the amount of cholesterol secreted by cumulus cells were significantly decreased.

CONCLUSIONS

TBX2 plays important roles in regulating the cells' proliferation, expansion, apoptosis, and autophagy; maintaining the mitochondrial function and cholesterol generation of bovine cumulus cells.

The role of oxidative stress in ovarian aging: a review

Ovarian aging refers to the process by which ovarian function declines until eventual failure. The pathogenesis of ovarian aging is complex and diverse; oxidative stress (OS) is considered to be a key factor. This review focuses on the fact that OS status accelerates the ovarian aging process by promoting apoptosis, inflammation, mitochondrial damage, telomere shortening and biomacromolecular damage. Current evidence suggests that aging, smoking, high-sugar diets, pressure, superovulation, chemotherapeutic agents and industrial pollutants can be factors that accelerate ovarian aging by exacerbating OS status. In addition, we review the role of nuclear factor E2-related factor 2 (Nrf2), Sirtuin (Sirt), mitogen-activated protein kinase (MAPK), protein kinase B (AKT), Forkhead box O (FoxO) and Klotho signaling pathways during the process of ovarian aging. We also explore the role of antioxidant therapies such as melatonin, vitamins, stem cell therapies, antioxidant monomers and Traditional Chinese Medicine (TCM), and investigate the roles of these supplements with respect to the reduction of OS and the improvement of ovarian function. This review provides a rationale for antioxidant therapy to improve ovarian aging.

Human fertility and sleep disturbances: A narrative review

INTRODUCTION

Many factors may be hidden behind the global fertility decline observed in Western countries. Alongside the progressively increased age of infertile couples, environmental and behavioural factors, including non-optimal lifestyle habits, should be considered. Among these, sleep disorders have been suggested to be linked to human fertility.

METHODS

This is a narrative review, describing first sleep physiology, its disturbances, and the tools able to quantify sleep dysfunction. Then, we consider all available studies aimed at investigating the connection between sleep disorders and human fertility, providing a comprehensive view on this topic.

RESULTS

Forty-two studies investigating the relationship between sleep habits and human reproduction were included. All the published evidence was grouped according to the aspect of human fertility considered, i.e. i) female reproductive functions, ii) male reproductive functions, iii) natural conception and iv) assisted reproduction. For each of the sub-groups considered, the connection between sleep dysregulation and human fertility was classified according to specific sleep characteristics, such as sleep duration, quality, and habits. In addition, possible physio-pathological mechanisms proposed to support the link between sleep and fertility were summarized.

CONCLUSION

This review summarizes the most relevant findings about the intricate and still largely unknown network of molecular pathways involved in the regulation of circadian homeostasis, to which sleep contributes, essential for reproductive physiology. Thus, many mechanisms seem correlate sleep disorders to reproductive health, such as adrenal activation, circadian dysregulation, and genetic influences. This review highlights the need to properly designed trials on the topic.

Effects of Melatonin on the Transcriptome of Human Granulosa Cells, Fertilization and Blastocyst Formation

Melatonin is a promising reagent that can improve assisted reproductive technology (ART) outcomes in infertility patients. However, melatonin is not effective for all infertile patients, and it remains unclear for which patients melatonin would be effective. This study examined the effects of melatonin on ART outcomes and examined its mechanisms. Melatonin increased the fertilization rate in patients whose fertilization rates in the previous cycle were less than 50%, but not in patients whose fertilization rates were more than 50% in the previous cycle. Melatonin increased the blastocyst formation rate in patients whose embryo development rates in the previous cycle were less than 50%, but not in patients whose embryo development rates were more than 50% in the previous cycle. To clarify its mechanisms, transcriptome changes by melatonin treatment in granulosa cells (GCs) of the patients were examined by RNA-sequence. Melatonin treatment altered the transcriptomes of GCs of patients with poor ART outcomes so that they were similar to the transcriptomes of patients with good ART outcomes. The altered genes were associated with the inhibition of cell death and T-cell activity, and the activation of steroidogenesis and angiogenesis. Melatonin treatment was effective for patients with poor fertilization rates and poor embryo development rates in the previous ART cycle. Melatonin alters the GCs transcriptome and, thus, their functions, and this could improve the oocyte quality, leading to good ART outcomes.

Melatonin treatment during chronic hypoxic gestation improves neonatal cerebrovascular function

BACKGROUND

Fetal chronic hypoxia is associated with blood flow redistribution and oxidative damage in the brain, leading to increased perinatal morbimortality. Melatonin reduces oxidative stress, improves vascular function, and has neuroprotective effects.

OBJECTIVES

This study aimed to determine the effects of an oral melatonin treatment to pregnant ewes at high-altitude, on the cerebrovascular function of their neonates.

STUDY DESIGN

Ten high-altitude pregnant sheep received either vehicle or melatonin (10 mg/d) during the last third of gestation until delivery. Postnatal daily hemodynamic measurements were recorded from lambs until 12 days old. In addition, lambs were submitted to a graded oxygenation protocol to assess cerebrovascular responses. Subsequently, lambs were euthanized, and middle cerebral arteries (MCA) were collected for vascular function, protein levels, and morphostructural analyses.

RESULTS

Antenatal treatment doubled plasma levels of melatonin in pregnant ewes. Melatonin increased carotid flow and decreased carotid vascular resistance in the lambs by the end of the first week. Furthermore, melatonin increased MCA's maximal vasoconstrictor and vasodilator responses, associated with nitric oxide-dependent and independent mechanisms.

CONCLUSIONS

An oral treatment with melatonin during pregnancy promotes postnatal cerebral perfusion in chronically hypoxic neonates. Melatonin is a potential treatment for cerebrovascular dysfunction due to perinatal chronic hypoxia.

Effects of different concentrations of eugenol in maturation medium on bovine oocytes, oxidative status and preimplantation embryos

ContextEugenol is a bioactive compound with defined attributes, including a role in reducing oxidative stress. Therefore, it is an interesting candidate for in vitro embryo production that has an environment that favours the formation of reactive oxygen species.AimThe objective of the study was to evaluate different concentrations of eugenol in bovine oocytes during in vitro maturation to observe the oxidative status and embryonic development.MethodsOocytes were allocated into five groups: control (without antioxidant), 100μM cysteamine, 83μM eugenol (E83), 100μM eugenol and 120μM eugenol. Three experiments were performed with 23 replicates. Oocytes were evaluated for metaphase II, first polar body, cytoplasmic maturation, cumulus cell expansion and viability. Oxidative status was measured by mitochondrial membrane potential, reactive oxygen species and glutathione. Oocytes were artificially activated and cultured in vitro.Key resultsThe presence of eugenol at 83μM improved the metaphase II rate compared with all treatments (P&lt;0.05). E83 and 100μM cysteamine improved first polar body extrusion, cumulus cell expansion, viability and mitochondrial aggregation rates (P&lt;0.05). All antioxidant treatments resulted in increased cytoplasmic maturation and decreased mitochondrial membrane potential (P&lt;0.05). Reactive oxygen species levels decreased, and glutathione levels increased with E83 and 100μM cysteamine treatments (P&lt;0.05). Finally, the E83 group increased the cleavage rates, embryo development, number of expanded blastocysts and number of blastomeres (P&lt;0.05).ConclusionsA low concentration of eugenol (83μM) is sufficient to generate a significant effect, attenuating the oxidative status and optimising in vitro maturation and embryo development.ImplicationsThis study provides information of a new natural antioxidant with defined concentration, 83μM eugenol, representing a lower cost alternative capable of improving the efficiency of in vitro embryo production in cattle.

The Role and Mechanism of Oxidative Stress and Nuclear Receptors in the Development of NAFLD

The overproduction of reactive oxygen species (ROS) and consequent oxidative stress contribute to the pathogenesis of acute and chronic liver diseases. It is now acknowledged that nonalcoholic fatty liver disease (NAFLD) is characterized as a redox-centered disease due to the role of ROS in hepatic metabolism. However, the underlying mechanisms accounting for these alternations are not completely understood. Several nuclear receptors (NRs) are dysregulated in NAFLD, and have a direct influence on the expression of a set of genes relating to the progress of hepatic lipid homeostasis and ROS generation. Meanwhile, the NRs act as redox sensors in response to metabolic stress. Therefore, targeting NRs may represent a promising strategy for improving oxidation damage and treating NAFLD. This review summarizes the link between impaired lipid metabolism and oxidative stress and highlights some NRs involved in regulating oxidant/antioxidant turnover in the context of NAFLD, shedding light on potential therapies based on NR-mediated modulation of ROS generation and lipid accumulation.

Roles of melatonin in the field of reproductive medicine

Melatonin, mostly released by the pineal gland, is a circadian rhythm-regulated and multifunctional hormone. Great advances in melatonin research have been made, including its role in rhythms of the sleep-wake cycle, retardation of ageing processes, as well as antioxidant or anti-inflammatory functions. Melatonin can scavenge free radicals such as reactive oxygen species (ROS), a key factor in reproductive functions. Melatonin plays an important role in oocyte maturation, fertilization and embryonic development as well. The concurrent use of melatonin increases the number of mature oocytes, the fertilization rate, and number of high-quality embryos, which improves the clinical outcome of assisted reproductive technology (ART). This review discusses the relationship between melatonin and human reproductive function, and potential clinical applications of melatonin in the field of reproductive medicine.

Melatonin promotes in vitro maturation of vitrified-warmed mouse GV oocytes potentially by modulating MAD2 protein expression of SAC component through MTRs

Previous studies have shown that melatonin (MT) can ameliorate vitrification-inflicted damage in mouse germinal vesicle (GV) oocytes, however, the key mechanistic basis of this improvement still remains poorly understood. This study was conducted to investigate whether MT can improve in vitro developmental potential of vitrified-warmed GV oocytes through its receptors. The fresh oocytes were randomly divided into four groups: untreated (control group, F), vitrified by open-pulled straw method (vitrification group, V), vitrification group with 100 nmol/L MT supplementation (vitrification + MT group, VM), and with 100 nmol/L MT plus 100 nmol/L luzindole administration (vitrification + MT + luzindole group, VML) or with 50 nmol/L ramelteon addition (vitrification + ramelteon group; VR). After warming, oocytes were cultured in vitro, and MT receptors (MTRs), MAD2 (mitotic arrest deficient 2), Securin and CyclinB1 protein levels and spindle morphology were evaluated. The ratio of oocytes developed to the metaphase I (MI) and metaphase II (MII) stages was also assessed. The results showed that after vitrification-warming, the in vitro maturation rate of GV oocytes was significantly lower compared to the control (F) group. Vitrification also significantly impaired the spindle morphology, decreased the protein level of MTRs and Securin, and decreased MAD2 levels in MI oocytes. However, when MT or ramelteon (MTRs agonist) were added (group wise) to warming and maturation media, the maturation rate of GV oocytes was significantly increased, the normal proportion of the spindle morphology increased, and the expression level of MAD2 increased in their resulting MI oocytes compared to the vitrification group. However, following addition of both MT and ramelteon, the maturation rate of GV oocyte showed no significant difference between VML and vitrification groups. The spindle morphology and MAD2 levels in MI oocytes were comparable to the vitrification group but differed significantly from the VM group. Taken together, finding of the present study shows that MT (100 nmol/L) can ameliorate the in vitro maturation of vitrified-warmed mouse GV oocytes, potentially by improving the spindle morphology, modulating MAD2 protein level and promoting the development of MI stage oocytes through MTRs.

Two melatonin treatments improve the conception rate after fixed-time artificial insemination in beef heifers following synchronisation of oestrous cycles using the CoSynch-56 protocol

OBJECTIVE

This study investigated the effect of melatonin administration in combination with the CoSynch-56 protocol on the conception rate after artificial insemination (AI) in beef heifers.

METHODS

Eighty-six beef heifers were allocated to four treatments in combination with CoSynch-56 treatment. All heifers, excluding the control group (CTR = 25), were injected with melatonin on day 1. The melatonin (MT = 20) and MT + human chorionic gonadotropin (MT + hCG = 21) groups received no further treatment with melatonin. Each heifer was treated with gonadotropin-releasing hormone (GnRH) on day 4, prostaglandin F2α (PGF2α) on day 11, and GnRH and AI 56 h later. The fourth group (2MT = 20) was injected again with melatonin concurrent with AI, and the MT + hCG group received hCG on day 19. Pregnancy diagnosis was performed using transrectal ultrasonography 45 days after AI and blood samples were collected via caudal venipuncture on days 0-1, 14-15, 24 and 59. Concentrations of progesterone (P4) and the activities of oxidative stress-related enzymes were determined using enzyme-linked immunosorbent assay.

RESULTS

The conception rate was greater in the 2MT group (75%) than in the other groups, while there was no significant difference among the CTR (44%), MT (45%) and MT + hCG (38.1%) groups. Treatment with melatonin increased superoxide dismutase and glutathione peroxidase activities and decreased malondialdehyde concentrations but did not significantly affect the concentration of P4.

CONCLUSION

Our results indicate that the administration of melatonin twice during the CoSynch-56 protocol may increase conception rates in beef heifers.

Characterization of Glutathione Peroxidase 4 in Rat Oocytes, Preimplantation Embryos, and Selected Maternal Tissues during Early Development and Implantation

This study aimed to describe glutathione peroxidase 4 (GPx4) in rat oocytes, preimplantation embryos, and female genital organs. After copulation, Sprague Dawley female rats were euthanized with anesthetic on the first (D1), third (D3), and fifth days of pregnancy (D5). Ovaries, oviducts, and uterine horns were removed, and oocytes and preimplantation embryos were obtained. Immunohistochemical, immunofluorescent, and Western blot methods were employed. Using immunofluorescence, we detected GPx4 in both the oocytes and preimplantation embryos. Whereas in the oocytes, GPx4 was homogeneously diffused, in the blastomeres, granules were formed, and in the blastocysts, even clusters were present mainly around the cell nuclei. Employing immunohistochemistry, we detected GPx4 inside the ovary in the corpus luteum, stroma, follicles, and blood vessels. In the oviduct, the enzyme was present in the epithelium, stroma, blood vessels, and smooth muscles. In the uterus, GPx4 was found in the endometrium, myometrium, blood vessels, and stroma. Moreover, we observed GPx4 positive granules in the uterine gland epithelium on D1 and D3 and cytoplasm of fibroblasts forming in the decidua on D5. Western blot showed the highest GPx4 levels in the uterus and the lowest levels in the ovary. Our results show that the GPx4 is necessary as early as in the preimplantation development of a new individual because we detected it in an unfertilized oocyte in a blastocyst and not only after implantation, as was previously thought.

RORα Regulates Odontoblastic Differentiation and Mediates the Pro-Odontogenic Effect of Melatonin on Dental Papilla Cells

Dental papilla cells (DPCs), precursors of odontoblasts, are considered promising seed cells for tissue engineering. Emerging evidence suggests that melatonin promotes odontoblastic differentiation of DPCs and affects tooth development, although the precise mechanisms remain unknown. Retinoid acid receptor-related orphan receptor α (RORα) is a nuclear receptor for melatonin that plays a critical role in cell differentiation and embryonic development. This study aimed to explore the role of RORα in odontoblastic differentiation and determine whether melatonin exerts its pro-odontogenic effect via RORα. Herein, we observed that RORα was expressed in DPCs and was significantly increased during odontoblastic differentiation in vitro and in vivo. The overexpression of RORα upregulated the expression of odontogenic markers, alkaline phosphatase (ALP) activity and mineralized nodules formation (p < 0.05). In contrast, odontoblastic differentiation of DPCs was suppressed by RORα knockdown. Moreover, we found that melatonin elevated the expression of odontogenic markers, which was accompanied by the upregulation of RORα (p < 0.001). Utilising small interfering RNA, we further demonstrated that RORα inhibition attenuated melatonin-induced odontogenic gene expression, ALP activity and matrix mineralisation (p < 0.01). Collectively, these results provide the first evidence that RORα can promote odontoblastic differentiation of DPCs and mediate the pro-odontogenic effect of melatonin.

Effects of melatonin on protecting against lung injury (Review)

Melatonin (MT; N-acetyl-5-methoxy-tryptamine), which has multiple effects and roles, is secreted from the pineal gland at night according to the daily rhythm. In addition to circadian regulation, MT has anti-inflammatory, antioxidant and anticancer functions. Recent studies postulated that MT serves a critical role in apoptosis, anti-ischemic reperfusion injury and anti-proliferative effects on various cells. The current review reported on the underlying mechanism behind the protective effect of MT on lung diseases, such as acute lung injury, acute respiratory distress syndrome, chronic obstructive pulmonary disease, lung ischemia-reperfusion injury, sepsis-induced lung injury and ventilator-induced lung injury. MT is considered an adjuvant with therapeutic drugs for preventing inflammation and is responsible for regulating patient sleep cycles in the intensive care unit. The current review described the anti-inflammatory and antioxidant efficiency of MT with a focus on the molecular mechanisms of action in various lung injuries.

The Roles of the miRNAome and Transcriptome in the Ovine Ovary Reveal Poor Efficiency in Juvenile Superovulation

Simple Summary

Using the technology of juvenile superovulation, more follicles can be acquired in juvenile animals than in adult animals. However, oocytes derived from the follicles of juvenile animals are usually of poor quality, meaning that they have lower levels of subsequent maturation and embryonic development. In the present study, we used an exogenous hormone treatment to stimulate Hu sheep in order to compare the differences in ovarian superovulation effects and serum hormone secretion in juvenile and adult sheep. Differentially expressed microRNA (miRNA) and messenger RNA (mRNA) from the ovaries of juvenile and adult Hu sheep were then investigated using high-throughput sequencing technology to reveal the formation mechanism of large numbers of follicles and poor oocyte quality in juvenile ovaries under superovulation treatment. We found that molecules of oar-miR-143 and follicle-stimulating hormone receptor (FSHR), among others, might regulate follicle formation, while oar-miR-485-3p, oar-miR-377-3p, and pentraxin 3 (PTX3), among others, may be associated with oocyte quality. The results will help us to identify miRNAs and mRNAs that could be used to predict ovarian superovulation potential and oocyte quality in the future.

Abstract

Juvenile superovulation can provide a wealth of oocyte material for embryo production, animal cloning, and genetic modification research, but embryos derived from juvenile oocytes show poor efficiency in subsequent developmental capacity. In order to reveal the formation mechanism of large numbers of follicles and poor oocyte quality in juvenile ovaries under superovulation treatment, differentially expressed microRNAs (miRNAs) and messenger RNAs (mRNAs) were characterized and investigated in the ovaries of lambs and adult sheep using high-throughput sequencing technology. The majority of differentially expressed miRNAs (337/358) were upregulated in lamb libraries. The expression levels of mRNAs related to hormone receptors (follicle-stimulating hormone receptor, FSHR; luteinizing hormone/choriogonadotropin receptor, LHCGR; estrogen receptor 1, ESR1), steroid hormone secretion (cytochrome P450 family 11 subfamily A member 1, CYP11A1; cytochrome P450 family 17 subfamily A member 1, CYP17A1; cytochrome P450 family 19 subfamily A member 1, CYP19A1), and oocyte quality (pentraxin 3, PTX3; BCL2 apoptosis regulator, BCL2; caspase 3, CASP3) were significantly different between the lamb and adult libraries. The miRNA aor-miR-143, which targets FSHR, was highly and differentially expressed, and PTX3 was predicted to be targeted by oar-miR-485-3p and oar-miR-377-3p in the ovine ovary. A considerable number of miRNAs were predicted to inhibit ESR1 expression in lamb ovaries. In conclusion, oar-miR-143 and FSHR molecules, among others, might regulate follicle formation, and oar-miR-485-3p, oar-miR-377-3p, and PTX3, among others, may be associated with oocyte quality. These identified miRNAs and mRNAs will be beneficial for the prediction of ovarian superovulation potential and screening of oocytes.

Ameliorative effect of melatonin on apoptosis, DNA fragmentation, membrane integrity and lipid peroxidation of spermatozoa in the idiopathic asthenoteratospermic men: In vitro

Fertility loss, recurrent spontaneous abortion and poor outcome in assisted reproductive techniques (ART) have been associated with DNA fragmentation. This work was achieved to evaluate the protective role of melatonin versus apoptosis, DNA fragmentation, membrane integrity and lipid peroxidation of spermatozoa from men with asthenoteratozoospermia (ATS). Some researchers maintain that melatonin can serve as a remedy for apoptosis induction, and it has an impressive effect on boosting the quality and quantity of spermatozoa. For this purpose, semen samples were collected from 50 ATS men and they were divided into control and melatonin (6 mM) groups at 2, 4, 6 and 24 hr. Concentrating on the reasons for apoptosis is an arduous process, but in the present study for this evaluation mitochondrial membrane potential (MMP), DNA fragmentation by TUNEL and sperm chromatin dispersion (SCD) methods and lipid peroxidation were carried out. Also, sperm viability was performed. In the control group, MDA, TUNEL-positive and SCD were significantly increased but viability and MMP of spermatozoa were significantly decreased. Moreover, in the melatonin group, TUNEL-positive, SCD and MDA levels were significantly decreased and viability and MMP significantly increased, compared to the control group. In outcome, melatonin prescription paves the way for apoptosis down-regulating in the ATS men.

Melatonin inhibits vascular endothelial cell pyroptosis by improving mitochondrial function via up-regulation and demethylation of UQCRC1

Atherosclerosis (AS) is a chronic inflammatory disease that involves cell death and endothelial dysfunction. Melatonin is an endocrine hormone with anti-inflammatory and anti-AS effects. However, the underlying molecular mechanisms for the anti-AS effects of melatonin are unknown. A previous study has shown that pyroptosis plays a detrimental role in the development of AS, therefore, this study was designed to investigate the anti-pyroptotic effects and potential mechanisms of melatonin in atherosclerotic endothelium. Our results show that melatonin attenuated the expression of genes related to pyroptosis, including NLRP3, caspase-1, and IL-1β, in human umbilical vein endothelial cells treated with oxidized low-density lipoprotein. Furthermore, melatonin up-regulated the expression of ten-eleven translocation 2 (TET2), inhibited the methylation of ubiquinol-cytochrome c reductase core protein 1 (UQCRC1), and reduced pyroptosis. The up-regulation of UQCRC1 by melatonin improved mitochondrial function, thereby inhibiting oxidative stress and endothelial cell pyroptosis. Collectively, our results indicate that melatonin prevents endothelial cell pyroptosis by up-regulating TET2 to inhibit the methylation of UQCRC1 and improving mitochondrial function.

Effect of melatonin supplementation on oxidative stress parameters: A systematic review and meta-analysis

BACKGROUND

Oxidative stress, defined as an imbalance between pro-oxidants and neutralizing antioxidants within the body, is a growing public health concern. Oxidative stress is involved in the progression of nearly all chronic diseases. Melatonin has been suggested to reduce oxidative stress by its potential radical scavenging properties.

OBJECTIVE

To determine the efficacy and safety of melatonin as a therapy for the improvement of oxidative stress parameters in randomized controlled trials.

METHODS

A systematic database search using Scopus, PubMed/Medline, EMBASE, Web of Science, the Cochrane Controlled Register of Trials and clinicaltrials.gov (https://clinicaltrials.gov) for studies published up to July 2020 was conducted. We included studies which investigated the effect of supplemental melatonin compared to placebo on oxidative stress parameters in unhealthy patients. Quantitative data synthesis was conducted using a random-effects model with standard mean difference (SMD) and 95 % confidence intervals (CI). Cochrane's Q and I² values were used to evaluate heterogeneity.

RESULTS

A total of 12 randomized controlled trials (RCTs) were eligible. The meta-analysis indicated an association between melatonin intake and a significant increase in total antioxidant capacity (TAC) (SMD: 0.76; 95 % CI: 0.30, 1.21; I² = 80.1 %), glutathione (GSH) levels (SMD: 0.57; 95 % CI: 0.32, 0.83; I² = 15.1 %), superoxide dismutase (SOD) (SMD: 1.38; 95 % CI: 0.13, 2.62; I² = 86.9 %), glutathione peroxidase (GPx) (SMD: 1.36; 95 % CI: 0.46, 2.30; I² = 89.3 %), glutathione reductase (GR) (SMD: 1.21; 95 % CI: 0.65, 1.77; I² = 00.0 %) activities, and a significant reduction in malondialdehyde (MDA) levels (SMD: -0.79; 95 % CI: -1.19, -0.39; I² = 73.1 %). Melatonin intake was not shown to significantly affect nitric oxide (NO) levels (SMD: -0.24; 95 % CI: -0.61, 0.14; I² = 00.0 %) or catalase (CAT) activity (SMD: -1.38; 95 % CI: -1.42, 4.18; I² = 96.6 %).

CONCLUSION

Melatonin intake was shown to have a significant impact on improving Oxidative stress parameters. However, future research through large, well-designed randomized controlled trials are required to determine the effect of melatonin on oxidative stress parameters in different age groups and different disease types.

Detection of the 23-bp nucleotide sequence mutation in retinoid acid receptor related orphan receptor alpha (RORA) gene and its effect on sheep litter size

Retinoid acid receptor related orphan receptor alpha (RORA) transcribes steroid-related genes to regulate estrogen synthesis. As an important reproductive trait, litter size relates to estrogen synthesis. Therefore, it is important to investigate the association between RORA gene and sheep litter size. In this study, one 23-bp nucleotide sequence mutation was identified in intron 1 of RORA gene in 532 female Australian White Sheep. Moreover, the polymorphic information content (PIC) values of this locus was 0.219. The litter size of ID genotype was significantly better than II genotype and DD genotype in the second born litter size (p < 0.05). This loci was related to third born litter size and the ID is the dominant genotype (p < 0.05). The association between combined genotypes and average litter size showed that sheep with heterozygote (ID) genotypes had larger lamb than homozygous (DD and II) genotypes. To sum, this study provided theoretical references for the comprehensively research of the function of RORA gene and the breeding of Australian White Sheep. The 23-bp indel variants could be considered as molecular markers for the second and third born litter size of sheep for MAS breeding.

Genome-Protecting Compounds as Potential Geroprotectors

Throughout life, organisms are exposed to various exogenous and endogenous factors that cause DNA damages and somatic mutations provoking genomic instability. At a young age, compensatory mechanisms of genome protection are activated to prevent phenotypic and functional changes. However, the increasing stress and age-related deterioration in the functioning of these mechanisms result in damage accumulation, overcoming the functional threshold. This leads to aging and the development of age-related diseases. There are several ways to counteract these changes: 1) prevention of DNA damage through stimulation of antioxidant and detoxification systems, as well as transition metal chelation; 2) regulation of DNA methylation, chromatin structure, non-coding RNA activity and prevention of nuclear architecture alterations; 3) improving DNA damage response and repair; 4) selective removal of damaged non-functional and senescent cells. In the article, we have reviewed data about the effects of various trace elements, vitamins, polyphenols, terpenes, and other phytochemicals, as well as a number of synthetic pharmacological substances in these ways. Most of the compounds demonstrate the geroprotective potential and increase the lifespan in model organisms. However, their genome-protecting effects are non-selective and often are conditioned by hormesis. Consequently, the development of selective drugs targeting genome protection is an advanced direction.

Importance of Melatonin in Assisted Reproductive Technology and Ovarian Aging

Melatonin is probably produced in all cells but is only secreted by the pineal gland. The pineal secretion of melatonin is determined by the light–dark cycle, and it is only released at night. Melatonin regulates biological rhythms via its receptors located in the suprachiasmatic nuclei of the hypothalamus. Melatonin also has strong antioxidant activities to scavenge free radicals such as reactive oxygen species (ROS). The direct free radical scavenging actions are receptor independent. ROS play an important role in reproductive function including in the ovulatory process. However, excessive ROS can also have an adverse effect on oocytes because of oxidative stress, thereby causing infertility. It is becoming clear that melatonin is located in the ovarian follicular fluid and in the oocytes themselves, which protects these cells from oxidative damage as well as having other beneficial actions in oocyte maturation, fertilization, and embryo development. Trials on humans have investigated the improvement of outcomes of assisted reproductive technology (ART), such as in vitro fertilization and embryo transfer (IVF-ET), by way of administering melatonin to patients suffering from infertility. In addition, clinical research has examined melatonin as an anti-aging molecule via its antioxidative actions, and its relationship with the aging diseases, e.g., Alzheimer’s and Parkinson’s disease, is also underway. Melatonin may also reduce ovarian aging, which is a major issue in assisted reproductive technology. This review explains the relationship between melatonin and human reproductive function, as well as the clinical applications expected to improve the outcomes of assisted reproductive technology such as IVF, while also discussing possibilities for melatonin in preventing ovarian aging.

Advances in Characterizing Recently-Identified Molecular Actions of Melatonin: Clinical Implications

Melatonin, N-acetyl-5-methoxy-tryptamine, was discovered to be a product of serotonin metabolism in the mammalian pineal gland where its synthesis is under control of the light:dark cycle. Besides its regulatory pathway involving ganglion cells in the retina, the neural connections between the eyes and the pineal gland include the master circadian clock, the suprachiasmatic nuclei, and the central and peripheral nervous systems. Since pineal melatonin is released into the blood and into the cerebrospinal fluid, it has access to every cell in an organism and it mediates system-wide effects. Subsequently, melatonin was found in several extrapineal organs and, more recently, perhaps in every cell of every organ. In contrast to the pinealocytes, non-pineal cells do not discharge melatonin into the blood; rather it is used locally in an intracrine, autocrine, or paracrine manner. Melatonin levels in non-pineal cells do not exhibit a circadian rhythm and do not depend on circulating melatonin concentrations although when animals are treated with exogenous melatonin it is taken up by presumably all cells. Mitochondria are the presumed site of melatonin synthesis in all cells; the enzymatic machinery for melatonin synthesis has been identified in mitochondria. The association of melatonin with mitochondria, because of its ability to inhibit oxidative stress, is very fortuitous since these organelles are a major site of damaging reactive oxygen species generation. In this review, some of the actions of non-pineal-derived melatonin are discussed in terms of cellular and subcellular physiology.

Antenatal melatonin modulates an enhanced antioxidant/pro-oxidant ratio in pulmonary hypertensive newborn sheep

Chronic hypobaric hypoxia during fetal and neonatal life induces neonatal pulmonary hypertension. Hypoxia and oxidative stress are driving this condition, which implies an increase generation of reactive oxygen species (ROS) and/or decreased antioxidant capacity. Melatonin has antioxidant properties that decrease oxidative stress and improves pulmonary vascular function when administered postnatally. However, the effects of an antenatal treatment with melatonin in the neonatal pulmonary function and oxidative status are unknown. Therefore, we hypothesized that an antenatal therapy with melatonin improves the pulmonary arterial pressure and antioxidant status in high altitude pulmonary hypertensive neonates. Twelve ewes were bred at high altitude (3600 m); 6 of them were used as a control group (vehicle 1.4% ethanol) and 6 as a melatonin treated group (10 mg d-1 melatonin in vehicle). Treatments were given once daily during the last third of gestation (100-150 days). Lambs were born and raised with their mothers until 12 days old, and neonatal pulmonary arterial pressure and resistance, plasma antioxidant capacity and the lung oxidative status were determined. Furthermore, we measured the pulmonary expression and activity for the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase, and the oxidative stress markers 8-isoprostanes, 4HNE and nitrotyrosine. Finally, we assessed pulmonary pro-oxidant sources by the expression and function of NADPH oxidase, mitochondria and xanthine oxidase. Melatonin decreased the birth weight. However, melatonin enhanced the plasma antioxidant capacity and decreased the pulmonary antioxidant activity, associated with a diminished oxidative stress during postnatal life. Interestingly, melatonin also decreased ROS generation at the main pro-oxidant sources. Our findings suggest that antenatal administration of melatonin programs an enhanced antioxidant/pro-oxidant status, modulating ROS sources in the postnatal lung.