Journal of Pineal Research最新文献

Melatonin is involved in biological adverse stress response and enhances the ability of yeast to adapt to adverse conditions. This study investigated the mechanism of exogenous melatonin addition to Saccharomyces cerevisiae (S. cerevisiae) under copper stress. The results indicated that the addition of excessive exogenous melatonin (100 mg/L) led to the accumulation of maltose and trehalose in S. cerevisiae, which slowed glucose metabolism and further suppressed the alcoholic fermentation process. The cell morphology, cell wall structure, and the organelle morphology of S. cerevisiae EC1118 under copper stress improved with the addition of 1 μg/mL of melatonin. The results of gas chromatography–mass spectrometry (GC–MS) indicated that melatonin induced more creamy and waxy flavors in the fermentation broth, whereas excessive melatonin led to the production of unpleasant fats with a coconut oil smell. The metabolomics results showed that melatonin promoted the synthesis of Cup1p and increased copper resistance by upregulating the sulfur-containing amino acids methionine and cysteine. Furthermore, lipid peroxidation and DNA damage were alleviated through the upregulation of AFMK, which protected the integrity of the cell membrane, thereby the physiological mechanism of alleviating copper stress was achieved. Overall, moderate amounts of melatonin reduced the contraction of cells caused by copper stress and promoted the production of flavor substances. This study holds theoretical and practical importance for wine making and industrial wine production under copper stress.

Patients with chronic kidney disease (CKD) are at increased risk of acute kidney injury following exposure to contrast media. We evaluated the effect of melatonin, a potent antioxidant, as a protective strategy against contrast-induced acute kidney injury (CI-AKI), with a focus on molecular mechanisms. We randomized patients with an eGFR < 60 mL/min/1.73 m² undergoing coronary angiography (CAG) into melatonin (10 mg twice daily) or placebo groups. Treatment started 48 h before CAG and continued for a total of 6 days. Peripheral blood mononuclear cells (PBMCs) were collected at baseline, at the time of CAG, and at 6, 24, 48, 72 h, and Day 30 post-procedure. The primary outcome was the incidence of CI-AKI; secondary outcomes included kidney function, oxidative stress, mitochondrial function, and cell death pathways. Forty patients were randomized into either the treatment or placebo group. All subsequent analyses were conducted on an as-treat basis. The incidence of CI-AKI was significantly lower in the melatonin group compared to the placebo group (25% vs. 60%, p = 0.025). The melatonin group showed a significantly smaller percentage change in plasma neutrophil gelatinase-associated lipocalin (NGAL) at all time points. In the PBMC study, cellular oxidative stress was significantly reduced in the melatonin group at each time point, and mitochondrial oxidative stress was lower at 48–72 h. Mitochondrial respiration improved significantly, and both necrosis and necroptosis were reduced at 24 h. Melatonin administration effectively reduced the incidence of CI-AKI in CKD patients undergoing CAG. This protective effect was associated with decreased oxidative stress, enhanced mitochondrial function, and reduced cell death, suggesting melatonin as a promising preventive strategy for CI-AKI.

Trial Registration: TCTR20210123004

Selenium has the function of bio-stimulating hormone. However, the underlying physiological and molecular mechanisms of melatonin and abscisic acid as secondary messengers in improving cold tolerance by selenium are limited. This study investigated the effects of selenite on the cold stress of cucumber seedlings. The results showed that the content of endogenesis abscisic acid significantly changed with exogenous application of selenite under cold stress. Interestingly, we found that the content of iron significantly changed in this process. Iron uptake and distribution may be the important reason of selenium alleviates cold injury of cucumber seedlings. Whole genes transcriptome was used for screening key genes on leaf and root of cucumber seedlings. To determine the interrelation between abscisic acid and melatonin in selenite alleviating cold stress, abscisic acid inhibitor fluridone and melatonin synthesis inhibitor p-chlorophenylalanine were used for in-depth study. The results indicate that melatonin as upstream signal of ABA involved in selenium enhanced cucumber cold tolerance. The results of yeast single hybridization, EMSA, LUC, and overexpression transgenic showed that the transcription factor CsGATA3 regulates the expression of CsCOMT1 in vitro and in vivo and affects melatonin content. This study provides a theoretical basis for cucumber cultivation and breeding.

Circadian rhythm disruption (CRD), stemming from sleep disorders and/or shift work, is a risk factor for reproductive dysfunction. CRD has been reported to disturb nocturnal melatonin signaling, which plays a crucial role in female reproduction as a circadian regulator and an antioxidant. The hypothalamic-pituitary-ovarian (HPO) axis regulates female reproduction, with luteinizing hormone (LH) pulse pattern playing a pivotal role in folliculogenesis and steroidogenesis. However, the effect of CRD on the HPO axis and the involvement of melatonin remains unclear. Female CBA/CaJ mice underwent CRD modeling, which involves alternating between standard light conditions and an 8-h advance schedule every 3 days for 8 weeks, whereas control mice were maintained under a standard 12:12-h light/dark (LD) cycle. Subsequent measurements of diurnal melatonin levels, LH pulse patterns assessments via serial tail-tip blood sampling and evaluations of ovarian function were conducted. CRD altered the circadian rhythms of wheel-running activity and melatonin secretion in mice and led to an augmented LH pulse pattern, evidenced by increased LH pulse frequency, mean LH levels, and pituitary LH beta-subunit (LHβ) expression, irregular estrous cycles, abnormal luteal function, altered endocrine function, and ovarian oxidative stress. Melatonin treatment (10 mg/kg/day for 4 weeks) significantly improved the HPO axis disorder in CRD mice, decreasing the enhanced LH pulse frequency and pituitary LHβ expression. These findings were further validated using an in vitro LβT2 cell perfusion model. Furthermore, melatonin restored ovarian function and scavenged reactive oxygen species, thereby preventing apoptosis and preserving ovarian function. This study offers new insights into the impact of CRD on the HPO axis and emphasizes the potential of melatonin supplementation in mitigating its effects on female reproduction.

Light environment in the Arctic differs widely with the seasons. Studies of relationships between objectively measured circadian phase and amplitude of light exposure and melatonin in community-dwelling Arctic residents are lacking. This investigation combines cross-sectional (n = 24–62) and longitudinal (n = 13–27) data from week-long actigraphy (with light sensor), 24-h salivary melatonin profiles, and proxies of metabolic health. Data were collected within the same week bracketing spring equinox (SE), and winter/summer solstices (WS/SS). Drastic seasonal differences in blue light exposure (BLE) corresponded to seasonal changes in the 24-h pattern of melatonin, which was phase delayed and reduced in normalized amplitude (NA) during WS/SS compared to SE. The extent of individual melatonin's acrophase and Dim Light Melatonin Onset (DLMO) change from SE to WS correlated with that from SE to SS. Although similar in extent and direction, melatonin phase changes versus SE were linked to morning BLE deficit in WS, contrasting to evening BLE excess in SS. Seasonal changes in sleep characteristics were closely associated with changes in the phases of BLE and melatonin. Proxies of metabolic health included triglycerides (TG), high-density lipoprotein cholesterol (HDL), TG/HDL ratio, and cortisol. Adverse seasonal changes in these proxies were associated with delayed acrophases of BLE and melatonin during WS and SS. TG and TG/HDL were higher in WS and SS than in SE, and cross-sectionally correlated with later melatonin and BLE acrophases, while lower HDL was associated with later BLE onset and later melatonin acrophase. Overall, this study shows that optimal 24-h patterns of light exposure during SE is associated with an earlier acrophase and a larger 24-h amplitude of melatonin, and that both features are linked to better metabolic health. Improving light hygiene, in particular correcting winter morning light deficit and summer evening light excess may help maintain metabolic health at high latitudes. Novel solutions for introducing proper circadian light hygiene such as human-centric light technologies should be investigated to address these issues in future studies.