METTL3-mediated N6-methyladenosine modification of STAT5A promotes gastric cancer progression by regulating KLF4.

N6-methyladenosine (m6A) is the predominant post-transcriptional RNA modification in eukaryotes and plays a pivotal regulatory role in various aspects of RNA fate determination, such as mRNA stability, alternative splicing, and translation. Dysregulation of the critical m6A methyltransferase METTL3 is implicated in tumorigenesis and development. Here, this work showed that METTL3 is upregulated in gastric cancer tissues and is associated with poor prognosis. METTL3 methylates the A2318 site within the coding sequence (CDS) region of STAT5A. IGF2BP2 recognizes and binds METTL3-mediated m6A modification of STAT5A through its GXXG motif in the KH3 and KH4 domains, leading to increased stability of STAT5A mRNA. In addition, both METTL3 and IGF2BP2 are positively correlated with STAT5A in human gastric cancer tissue samples. Helicobacter pylori infection increased the expression level of METTL3 in gastric cancer cells, thereby leading to the upregulation of STAT5A. Functional studies indicated that STAT5A overexpression markedly enhances the proliferation and migration of GC cells, whereas STAT5A knockdown has inhibitory effects. Further nude mouse experiments showed that STAT5A knockdown effectively inhibits the growth and metastasis of gastric cancer in vivo. Moreover, as a transcription factor, STAT5A represses KLF4 transcription by binding to its promoter region. The overexpression of KLF4 can counteract the oncogenic impact of STAT5A. Overall, this study highlights the crucial role of m6A in gastric cancer and provides potential therapeutic targets for gastric cancer.

Pleurotus eryngii root waste and soybean meal co-fermented protein improved the growth, immunity, liver and intestinal health of largemouth bass (Micropterus salmoides).

The present study aimed to evaluate the effect of king oyster mushroom (Pleurotus eryngii) root waste and soybean meal co-fermented protein (CFP) on growth performance, feed utilization, immune status, hepatic and intestinal health of largemouth bass (Micropterus salmoides). Largemouth bass (12.33 ± 0.18 g) were divided into five groups, fed with diets containing 0 %, 5 %, 10 %, 15 % and 20 % CFP respectively for 7 weeks. The growth performance and dietary utilization were slightly improved by the supplementation of CFP. In addition, improved immunoglobulin M (IgM) content and lysozyme activity in treatments confirm the enhancement of immunity in fish by the addition of CFP, especially in fish fed 20 % CFP (P < 0.05). Furthermore, CFP significantly improved liver GSH (glutathione) content in groups D10 and D15 (P < 0.05), and slightly improved total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity while slightly reduced malondialdehyde (MDA) content. Simultaneously, the upregulation of lipolysis-related genes (PPARα, CPT1 and ACO) expression and downregulation of lipid synthesis-related genes (ACC and DGAT1) expression was recorded in the group D20 compared with the control (P < 0.05), which were consistent with the decreased liver lipid contents, suggests that lipid metabolism was improved by CFP. In terms of intestinal structural integrity, ameliorated intestinal morphology in treatments were consistent with the upregulated Occludin, Claudin-1 and ZO-1 genes expression. The intestinal pro-inflammatory cytokines (TNF-α and IL-8) expression were suppressed while the anti-inflammatory cytokines (IL-10 and TGF-ß) were activated in treatments. The expression of antimicrobial peptides (Hepcidin-1, Piscidin-2 and Piscidin-3) and intestinal immune effectors (IgM and LYZ) were slightly up-regulated in treatments. Additionally, the relative abundance of intestinal beneficial bacteria (Firmicutes) increased while the relative abundance of potential pathogenic bacteria (Fusobacterium and Proteobacteria) decreased, which indicated that the intestinal microbial community was well-reorganized by CFP. In conclusion, dietary CFP improves growth, immunity, hepatic and intestinal health of largemouth bass, these data provided a theoretical basis for the application of this novel functional protein ingredient in fish.

Ubiquitin-specific Protease 35 Promotes Gastric Cancer Metastasis by Increasing the Stability of Snail1.

Deubiquitinase (DUB) dysregulation is closely associated with multiple diseases, including tumors. In this study, we used data from The Cancer Genome Atlas and Gene Expression Omnibus databases to analyze the expression of 51 ubiquitin-specific proteases (USPs) in gastric cancer (GC) tissues and adjacent non-neoplastic tissues. The Kaplan-Meier Plotter database was used to analyze the association of the differentially expressed USPs with the overall survival of patients with GC. The results showed that five USPs (USP5, USP10, USP13, USP21, and USP35) were highly expressed in GC tissues and were associated with poor prognosis in patients with GC. Because the epithelial-mesenchymal transition enables epithelial cells to acquire mesenchymal features and contributes to poor prognosis, we investigated whether these USPs had regulatory effects on the key epithelial-mesenchymal transition transcription factor Snail1. Our results showed that USP35 exhibited the most significant regulation on Snail1. Overexpression of USP35 increased and its knockdown decreased Snail1 protein levels. Mechanistically, USP35 interacted with Snail1 and removed its polyubiquitinated chain, thereby increasing its stability. Furthermore, USP35 promoted the invasion and migration of GC cells depending on its DUB activity. USP35 knockdown exhibited the opposite effect. Snail1 depletion partially abrogated the biological effects of USP35. Experiments using nude mouse tail vein injections indicated that wild-type USP35, but not the catalytically inactive USP35-C450A mutant, dramatically enhanced cell colonization and tumorigenesis in the lungs of mice. In addition, USP35 positively correlated with Snail1 expression in clinical GC tissues. Helicobacter pylori infection increased USP35 and Snail1 expression levels. Altogether, we found that USP35 can deubiquitinate Snail1 and increase its expression, thereby contributing to the malignant progression of GC. Therefore, USP35 may serve as a viable target for GC treatment.

USP13 deubiquitinates and stabilizes cyclin D1 to promote gastric cancer cell cycle progression and cell proliferation.

The reversible post-translational modifications of protein ubiquitination and deubiquitination play a crucial regulatory role in cellular homeostasis. Deubiquitinases (DUBs) are responsible for the removal of ubiquitin from the protein substrates. The dysregulation of the DUBs may give rise to the occurrence and development of tumors. In this study, we investigated the gastric cancer (GC) data from the TCGA and GEO databases and found that ubiquitin-specific protease USP13 was significantly up-regulated in GC samples. The higher expression of USP13 was associated with the worse prognosis and shorter overall survival (OS) of GC patients. Enforced expression of USP13 in GC cells promoted the cell cycle progression and cell proliferation in an enzymatically dependent manner. Conversely, suppression of USP13 led to GC cell cycle arrest in G1 phase and the inhibition of cell proliferation. Nude mouse experiments indicated that depletion of USP13 in GC cells dramatically suppressed tumor growth in vivo. Mechanistically, USP13 physically bound to the N-terminal domain of cyclin D1 and removed its K48- but not K63-linked polyubiquitination chain, thereby stabilizing and increasing cyclin D1. Furthermore, re-expression of cyclin D1 partially reversed the cell cycle arrest and cell proliferation inhibition induced by USP13 depletion in GC cells. Additionally, USP13 protein abundance was positively correlated with the protein level of cyclin D1 in human GC tissues. Taken together, our data demonstrate that USP13 deubiquitinates and stabilizes cyclin D1, thereby promoting cell cycle progression and cell proliferation in GC. These findings suggest that USP13 might be a promising therapeutic target for the treatment of GC.

Analysis of differential metabolites and metabolic pathways in adipose tissue of tree shrews (Tupaia belangeri) under gradient cooling acclimation.

In order to investigate the influence of gradient cooling acclimation on body mass regulation in tree shrews (Tupaia belangeri), white adipose tissue (WAT) and brown adipose tissue (BAT) in T. belangeri between the control group and gradient cooling acclimation group on day 56 were collected, body mass, food intake, thermogenic capacity, differential metabolites, and related metabolic pathways in WAT and BAT were measured, the changes of differential metabolites were analyzed by non-targeted metabolomics method based on liquid chromatography-mass spectrometry. The results shown that gradient cooling acclimation significantly increased body mass, food intake, resting metabolic rate (RMR), non-shivering thermogenesis (NST), and masses of WAT and BAT. 23 significant differential metabolites in WAT between the gradient cooling acclimation group and the control group, of which the relative contents of 13 differential metabolites were up-regulated and 10 differential metabolites were down-regulated. 27 significant differential metabolites in BAT, of which 18 differential metabolites decreased and 9 differential metabolites increased. 15 differential metabolic pathways in WAT, 8 differential metabolic pathways in BAT, and 4 differential metabolic pathways involved in both WAT and BAT, including Purine metabolism, Pyrimidine metabolism, Glycerol phosphate metabolism, Arginine and proline metabolism, respectively. All of the above results suggested that T. belangeri could use different metabolites of adipose tissue to withstand low temperature environments and enhance their survival.

Mendelian randomization analysis of the association between human blood cell traits and uterine polyps.

Human blood cells (HBCs) play essential roles in multiple biological processes but their roles in development of uterine polyps are unknown. Here we implemented a Mendelian randomization (MR) analysis to investigate the effects of 36 HBC traits on endometrial polyps (EPs) and cervical polyps (CPs). The random-effect inverse-variance weighted method was adopted as standard MR analysis and three additional MR methods (MR-Egger, weighted median, and MR-PRESSO) were used for sensitivity analyses. Genetic instruments of HBC traits was extracted from a large genome-wide association study of 173,480 individuals, while data for EPs and CPs were obtained from the UK Biobank. All samples were Europeans. Using genetic variants as instrumental variables, our study found that both eosinophil count (OR 0.85, 95% CI 0.79-0.93, P = 1.06 × 10-4) and eosinophil percentage of white cells (OR 0.84, 95% CI 0.77-0.91, P = 2.43 × 10-5) were associated with decreased risk of EPs. The results were robust in sensitivity analyses and no evidences of horizontal pleiotropy were observed. While we found no significant associations between HBC traits and CPs. Our findings suggested eosinophils might play important roles in the pathogenesis of EPs. Besides, out study provided novel insight into detecting uterine polyps biomarkers using genetic epidemiology approaches.

Metabolomics on serum levels and liver of male Tupaia belangeri from 12 locations in China by GC-MS.

OBJECTIVES: To investigate adaptive strategies of Tupaia belangeri to environmental factors in different populations, 12 locations were selected, including higher and lower altitude areas. RESULTS: Total of 96 and 90 metabolites were annotated in serum and liver respectively, which were mainly concentrated in primary metabolites. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) showed that the locations were divided into two groups in serum metabolites, but each group had a few samples overlap. The samples of each group overlap to some degree in the liver metabolites. The tricarboxylic acid (TCA) cycle occupies a central position in metabolism. The concentrations of TCA intermediates, lipid metabolites and amino acid metabolites were higher in higher altitude areas, and the concentrations of carbohydrate and glycolysis intermediates were higher in lower altitude areas. CONCLUSIONS: Different areas adapted to the changes of environmental and altitude by regulating the concentration of metabolites in serum and liver, and revealed the adaptive mechanism of T. belangeri in different living environments.

Behavioral neuroimaging in birds using PET.

BACKGROUND: Birds comprise the most diverse group of terrestrial vertebrates. This success likely is related to the evolution of powered flight over 75 mya. Modern approaches for studying brain function, however, have yet to be fully adapted and applied to birds, especially as they relate to specific behaviors including flight. New method: We have developed a comprehensive set of in vivo experimental methods utilizing PET imaging with F-18 labeled fluorodeoxyglucose (FDG) to study regional changes in metabolism specifically related to flight, yet applicable to other behaviors as well. It incorporates approaches for selection of species, behavioral/imaging paradigm, animal preparation, radiotracer injection route, image quantification, and image analysis via an enhanced brain atlas. We also carried out preliminary modeling studies to better understand tracer kinetics. RESULTS: The methods were successful in identifying brain regions statistically associated with flight using only 8 animals. Peak brain uptake of FDG between birds and rodents is similar despite much higher blood glucose levels in birds. We also confirmed that brain uptake of FDG steadily decreases after the initial peak and provide evidence that it may be related to greater dephosphorylation of FDG phosphate than that observed in mammals. Comparison with existing methods: FDG PET has been used in only a few studies of the bird brain. We introduce a new species, more realistic flight behavior, paired (test/retest) design, and improved quantification and analysis approaches. CONCLUSIONS: The proposed imaging protocol is non-invasive yet sensitive to regional metabolic changes in the bird brain related to behavior.