Melatonin attenuates chronic intermittent hypoxia-induced intestinal barrier dysfunction in mice.

BACKGROUND AND PURPOSE: Chronic intermittent hypoxia (CIH) triggers subclinical intestinal barrier disruption prior to systemic low-grade inflammation. Increasing evidence suggests therapeutic effects of melatonin on systemic inflammation and gut microbiota remodelling. However, whether and how melatonin alleviates CIH-induced intestinal barrier dysfunction remains unclear. EXPERIMENTAL APPROACH: C57BL/6 J mice and Caco-2 cell line were treated. We evaluated gut barrier function spectrophotometrically using fluorescein isothiocyanate (FITC)-labelled dextran. Immunohistochemical and immunofluorescent staining were used to detect morphological changes in the mechanical barrier. Western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) revealed the expression of tight junctions, signal transducer and activator of transcription 3 (STAT3) levels. 16 S rRNA analysis of the colonic contents microflora. Flow cytometry was used to detect cytokines and Th17 cells with and without melatonin supplementation. KEY RESULTS: We found that CIH could induce colonic mucosal injury, including reduction in the number of goblet cells and decrease the expression of intestinal tight junction proteins. CIH could decrease the abundance of the beneficial genera Clostridium, Akkermansia, and Bacteroides, while increasing the abundance of the pathogenic genera Desulfovibrio and Bifidobacterium. Finally, CIH facilitated Th17 differentiation via the phosphorylation of signal transducer and activator of transcription 3 (STAT3) in vitro and elevated the circulating pro-inflammatory cytokine in vivo. Melatonin supplementation ameliorated CIH-induced intestinal mucosal injury, gut microbiota dysbiosis, enteric Th17 polarization, and systemic low-grade inflammation reactions mentioned-above. CONCLUSION AND IMPLICATIONS: Melatonin attenuated CIH-induced intestinal barrier dysfunction by regulating gut flora dysbiosis, mucosal epithelium integrity, and Th17 polarization via STAT3 signalling.

Selenium-GPX4 axis protects follicular helper T cells from ferroptosis.

Follicular helper T (TFH) cells are a specialized subset of CD4+ T cells that essentially support germinal center responses where high-affinity and long-lived humoral immunity is generated. The regulation of TFH cell survival remains unclear. Here we report that TFH cells show intensified lipid peroxidation and altered mitochondrial morphology, resembling the features of ferroptosis, a form of programmed cell death that is driven by iron-dependent accumulation of lipid peroxidation. Glutathione peroxidase 4 (GPX4) is the major lipid peroxidation scavenger and is necessary for TFH cell survival. The deletion of GPX4 in T cells selectively abrogated TFH cells and germinal center responses in immunized mice. Selenium supplementation enhanced GPX4 expression in T cells, increased TFH cell numbers and promoted antibody responses in immunized mice and young adults after influenza vaccination. Our findings reveal the central role of the selenium-GPX4-ferroptosis axis in regulating TFH homeostasis, which can be targeted to enhance TFH cell function in infection and following vaccination.

A novel tumor suppressor CECR2 down regulation links glutamine metabolism contributes tumor growth in laryngeal squamous cell carcinoma.

PURPOSE: Glutamine plays an important role in tumor metabolism and progression. This research aimed to find out how Gln exert their effects on laryngeal squamous cell carcinoma (LSCC). METHODS: Cell proliferation was measured by CCK8 and EdU assay, mitochondrial bioenergetic activity was measured by mitochondrial stress tests. Gene expression profiling was revealed by RNA sequencing and validated by RT-qPCR. In LSCC patients, protein expression in tumor and adjacent tissues was examined and scored by IHC staining. RNAi was performed by stably expressed shRNA in TU177 cells. In vivo tumor growth analysis was performed using a nude mouse tumorigenicity model. RESULTS: Gln deprivation suppressed TU177 cell proliferation, which was restored by αKG supplementation. By transcriptomic analysis, we identified CECR2, which encodes a histone acetyl-lysine reader, as the downstream target gene for Gln and αKG. In LSCC patients, the expression of CECR2 in tumors was lower than adjacent tissues. Furthermore, deficiency of CECR2 promoted tumor cell growth both in vitro and in vivo, suggesting it has tumor suppressor effects. Besides, cell proliferation inhibited by Gln withdrawal could be restored by CECR2 depletion, and the proliferation boosted by αKG supplementation could be magnified either, suggested that CECR2 feedback suppressed Gln and αKG's effect on tumor growth. Transcriptomic profiling revealed CECR2 regulated the expression of a series of genes involved in tumor progression. CONCLUSION: We confirmed the Gln-αKG-CECR2 axis contributes to tumor growth in LSCC. This finding provided a potential therapeutic opportunity for the use of associated metabolites as a potential treatment for LSCC.

Efficacy of melatonin for sleep disturbance in middle-aged primary insomnia: a double-blind, randomised clinical trial.

BACKGROUND: The aim of this study was to determine the efficacy of exogenous melatonin supplementation for sleep disturbances in patients with middle-aged primary insomnia. METHODS: This is a randomized double-blind, placebo-controlled parallel study. Participants were recruited from Tianlin community, Xuhui district, Shanghai. Ninety-seven consecutive middle-aged patients with primary insomnia were randomized to receive 3 mg fast-release melatonin (n = 51) or placebo (n = 46) for four-weeks. Objective sleep parameters tested by overnight polysomnography, subjective sleep performance and daytime somnolence obtained from the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI) and Epworth Sleepiness Scale (ESS) were obtained at baseline and after treatment. Treatment was taken daily 1 h before bedtime. Serious adverse events and side-effects were monitored. RESULTS: Melatonin supplementation significantly decreased early wake time [-30.63min (95% CI, -53.92 to -7.34); P = 0.001] and percentage of N2 sleep [-7.07% (95% CI, -13.47% to -0.68%); P = 0.031]. However, melatonin had no significant effect on other objective sleep parameters including sleep latency, sleep efficiency, wake during the sleep and percent of N1, N3 and REM sleep. Melatonin had no effect on insomnia symptoms and severity on the PSQI [1.53(95% CI, -0.55 to 3.61); p = 0.504]; ISI [0.81 (95% CI, -2.27 to 3.88); p = 0.165] and ESS [-0.83 (95% CI, -3.53 to 1.88); p = 0.147]. No serious adverse events were reported. CONCLUSIONS: Melatonin supplementation over a four-week period is effective and safe in improving some aspects of objective sleep quality such as total sleep time, percentage of rapid eye movement and early morning wake time in middle-aged patients with insomnia. TRIAL REGISTRATION: Identifier: ChiCTR-TRC-13003997; Prospectively registered on 2 December 2013.