Molecular Medicine最新文献

Post-transcriptional RNA modifications have emerged as critical regulators of stemness, cellular plasticity, adaptation to stress and transformation. Amongst these the N6-methyladenosine (m⁶A) modification orchestrates a wide range of physiological processes; yet its contribution to metabolic regulation remains poorly addressed. In the present study, differential proteomics revealed enrichment of core components of the m⁶A machinery, viz. WTAP (writer) and IGF2BP3 (reader) in stem-like cells of the mesenchymal subtype of High-Grade Serous Ovarian Carcinoma (HGSC). Intriguingly, components of de novo cholesterol biosynthesis were also enriched. In investigating the suggested link between m⁶A regulation and sterol metabolism, we established a m⁶A-dependent stabilization of transcripts encoding rate-limiting de novo cholesterol biosynthetic enzymes by IGF2BP3 towards sustaining cholesterol production. Disruption of this cross-regulation by pharmacological inhibition impaired cell survival, self-renewal, and migration. Analyses of datasets from The Cancer Genome Atlas (TCGA) assigned a clinical significance to this regulatory axis through correlation of elevated expression of de novo cholesterol biosynthetic genes with poor progression-free survival of serous ovarian carcinoma patients. IGF2BP3 knock down, and chemical blockade of de novo cholesterol biosynthesis, both alone or in combination, achieved attenuated disease progression, in vivo. Effectively, our study links RNA modifications with metabolic reprogramming in the HGSC mesenchymal subtype through delineation of a m⁶A-IGF2BP3-cholesterol biosynthesis axis-mediated regulation of tumor cell stemness and aggression.

Background: Maternal fructose intake induces harmful effects in progeny. However, this sugar is not contraindicated during pregnancy. On the other hand, the use of low-calorie sweeteners, such as tagatose, is increasing. Thus, we have studied whether the consumption of tagatose compared to fructose affects lipid metabolism in the offspring of mothers which were supplemented with fructose during their pregnancy.

Methods: Three-month-old male rat offspring from control or fructose mothers received liquid 10% fructose or tagatose for 21 days. A control group (without any additive) was also included. Biochemical and molecular parameters were determined in plasma, tissues and feces.

Results: Both tagatose and fructose consumption caused hypertriglyceridemia in descendants of fructose-fed mothers. Whereas fructose consumption led to a greater hepatic lipogenesis, tagatose supplementation provoked a higher enterohepatic bile acids recirculation, and therefore a higher intestinal lipid absorption and assembly. However, plasma GLP1, a molecule that affects lipid intestinal absorption, was unchanged. Curiously, FGF21, a molecule which regulates lipid and carbohydrate metabolism and is sensitive to GLP1, was augmented in plasma and liver of tagatose-supplemented descendants regardless of their maternal diet. Interestingly, Angiotensin II (Ang II), which can induce FGF21 production, was increased in plasma of all animals supplemented with tagatose. However, the deleterious effects of Ang II were effectively reversed by FGF21 in males from control mothers, but not in descendants of fructose-fed dams.

Conclusions: Maternal fructose consumption determines the response of the offspring to tagatose intake, causing an increased intestinal lipid absorption, and metabolic changes that are characteristic of metabolic syndrome such as dyslipidaemia, steatosis and oxidative stress.

Background: PD-L1 immunotherapy plays a crucial role in cancer treatment, but PD-L1 peptide vaccines have low immunogenicity. A potent peptide derived from the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a significant adjuvant effect, which may increase the immunogenicity of the PD-L1 peptide. This study evaluates whether the PD-L1-SARS peptide enhances PD-L1 immunotherapy and analyzes its potential synergistic effects with anti-PD-L1 antibodies.

Methods: In vivo experiments compared prevention, therapy, and combination therapy using PD-L1 versus PD-L1-SARS peptides in mice. Cytokine multiplex arrays, ELISpot, and IHC were used to evaluate adjuvant effects. Molecular docking (hypothesis-generating), RNA-seq, and LC-MS/MS were used to explore putative mechanisms.

Results: The PD-L1-SARS peptide enhanced the Th1 immune response and increased CD8 and Th17 cell infiltration, effectively inhibiting tumor growth and liver metastasis. Additionally, it promoted M1 macrophage polarization and improved anti-PD-L1 antibody efficacy. Proteomics and bioinformatic analyses were consistent with IFN-γ-linked pathways, and an exploratory docking screen nominated candidate receptors/pathways potentially connecting the adjuvant motif to innate sensing.

Conclusions: Embedding a SARS-derived adjuvant-like motif within a PD-L1 peptide vaccine and delivering it in situ may re-condition the tumor microenvironment toward an immune-activating, Th1/Th17-biased state and complement PD-L1 blockade.

Background: Gastrointestinal acute radiation syndrome (GI-ARS) is characterized by disruption of the intestinal barrier function, leading to bacterial translocation and sepsis. Intestinal stem cells are highly radiosensitive and dramatically reduced after radiation injury. Clusterin (Clu)-positive revival stem cells contribute to the restoration of intestinal stem cells. Ghrelin, a gastric peptide hormone, has been shown to improve intestinal integrity in models of inflammatory enteropathy. In this study, we investigated the effects of ghrelin on intestinal stem cell recovery and its potential to mitigate radiation-induced intestinal injury.

Methods: Mice were subjected to 12 Gy partial body irradiation (PBI). Ghrelin at the doses of 2 to 6 nmol per mouse was administered daily for 4 consecutive days, starting at 24 h post-PBI, and survival was monitored for 30 days. To assess intestinal histology, cell proliferation, and intestinal stem cell markers, mice were treated with 6 nmol of ghrelin on days 1, 2, and 3 post-PBI, and on day 4 jejunal samples were collected for qPCR, immunofluorescence, and microcolony assays. Intestinal permeability was assessed in vivo by the leakage of gavage-fed 4-kDa FITC-dextran into the circulation.

Results: Ghrelin administration significantly improved 30-day survival rate following 12-Gy PBI in a dose-dependent manner. Treatment with ghrelin restored villus length and enhanced intestinal barrier integrity. Ghrelin also significantly increased the expression of proliferation markers in the jejunum. Microcolony assays revealed that ghrelin reversed the decrease in BrdU-positive cells following PBI. The mRNA and protein expression of intestinal stem cell markers was decreased after PBI but was restored by ghrelin treatment. Finally, ghrelin significantly increased the population of Clu⁺ population following irradiation.

Conclusions: These findings indicate that ghrelin mitigates radiation-induced intestinal injury by promoting the expansion of Clu⁺ revival stem cells and the recovery of intestinal stem cells. This study highlights the therapeutic potential and identifies the mechanism of action of ghrelin as a medical countermeasure against GI-ARS.

Background: This study explored the impact of vaginal microbes, metabolites, and METTL1-mediated m7G modification of BRCA1 mRNA on High-Grade Serous Ovarian Cancer (HGSOC).

Methods: METTL1 and BRCA1 expression levels were assessed via bioinformatics, Western blotting, and RT-qPCR. Their interaction was studied using RNA co-immunoprecipitation and RNA pull-down assays. The functions and mechanisms of METTL1 and BRCA1 in HGSOC were investigated through CCK-8 assays, flow cytometry, transwell migration assays, and nude mouse xenograft models. We analyzed vaginal microbial and metabolite differences in HGSOC patients with varying BRCA1 expression using 16 S rRNA sequencing and liquid chromatography. Associations were evaluated with Spearman correlation and heat maps, while molecular docking assessed key metabolite binding to METTL1. The roles and interactions of selected metabolites with METTL1/BRCA1 in HGSOC were validated through in vivo and in vitro experiments.

Results: In HGSOC, both METTL1 and BRCA1 were up-regulated. METTL1 enhanced BRCA1 expression via m7G modification, boosting cell proliferation and tumor growth. Elevated BRCA1 levels were associated with changes in vaginal microbiota, particularly increased Lactobacillus, and alterations in metabolic pathways. Correlation analysis indicated that Lactobacillus was significantly negatively correlated with 5-formamidoimidazole-4-carboxamide ribotide, inosine, cobalt-precorrin-7, and uridine, but positively correlated with L-lysine. The strongest correlation was with 5-formamidoimidazole-4-carboxamide ribotide. Molecular docking showed that this compound binds strongly to METTL1. Functional tests demonstrated that it inhibits HGSOC cell proliferation and tumor growth by disrupting METTL1-mediated m7G modification of BRCA1. Overexpression of METTL1 or BRCA1 negated its anti-tumor effects.

Conclusion: The vaginal microbial metabolite 5-formamidoimidazole-4-carboxamide ribotide reduces BRCA1 expression and slows HGSOC progression by modifying BRCA1 m7G through METTL1, suggesting its potential as an HGSOC treatment.