B4GALT5 a sialylation-related genes associated with patient prognosis and immune microenvironment in ovarian cancer and pan-cancer.

BACKGROUND: Ovarian cancer (OC) is the predominant primary tumor in the human reproductive system. Abnormal sialylation has a significant impact on tumor development, metastasis, immune evasion, angiogenesis, and treatment resistance. B4GALT5, a gene associated with sialylation, plays a crucial role in ovarian cancer, and may potentially affect clinicopathological characteristics and prognosis. METHODS: We conducted a comprehensive search across TIMER, GEPIA2, GeneMANIA, and Metascape to obtain transcription profiling data of ovarian cancer from The Cancer Genome Atlas (TCGA). The expression of B4GALT5 was test by immunohistochemistry. To investigate the impact of B4GALT5 on growth and programmed cell death in OC cells, we performed transwell assays and western blots. RESULTS: The presence of B4GALT5 was strongly associated with an unfavorable outcome in OC. B4GALT5 significantly promoted the proliferation of OC cells. Upon analyzing gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), it was discovered that B4GALT5 played a crucial role in the extracellular matrix, particularly in collagen-containing structures, and exhibited correlations with ECM-receptor interactions, transcriptional dysregulation in cancer, as well as the interleukin-1 receptor signaling pathway. Furthermore, there is a clear link between B4GALT5 and the tumor immune microenvironment in OC. Moreover, B4GALT5 exhibits favorable expression levels across various types of cancers, including CHOL, KIRC, STAD and UCES. CONCLUSION: In conclusion, it is widely believed that B4GALT5 plays a pivotal role in the growth and progression of OC, with its heightened expression serving as an indicator of unfavorable outcomes. Moreover, B4GALT5 actively participates in shaping the cancer immune microenvironment within OC. This investigation has the potential to contribute significantly to a deeper understanding of the substantial involvement of B4GALT5 in human malignancies, particularly OCs.

Downregulation of B4GALT5 attenuates cardiac fibrosis through Lumican and Akt/GSK-3ß/ß-catenin pathway.

Virtually all forms of cardiac disease exhibit cardiac fibrosis as a common trait, which ultimately leads to adverse ventricular remodeling and heart failure. To improve the prognosis of heart disease, it is crucial to halt the progression of cardiac fibrosis. Protein function is intricately linked with protein glycosylation, a vital post-translational modification. As a fundamental member of the ß1,4-galactosyltransferase gene family (B4GALT), ß1,4-galactosyltransferase V (B4GALT5) is associated with various disorders. In this study, significant levels of B4GALT5 expression were observed in cardiac fibrosis induced by transverse aortic constriction (TAC) or TGFß1 and the activation of cardiac fibroblasts (CFs). Subsequently, by administering AAV9-shB4GALT5 injections to TAC animals, we were able to demonstrate that in vivo B4GALT5 knockdown decreased the transformation of CFs into myofibroblasts (myoFBs) and reduced the deposition of cardiac collagen fibers. In vitro tests revealed the same results. Conversely, both in vivo and in vitro experiments indicated that overexpression of B4GALT5 stimulates CFs activation and exacerbates cardiac fibrosis. Initially, we elucidated the primary mechanism by which B4GALT5 regulates the Akt/GSK-3ß/ß-catenin pathway and directly interacts with laminin, thereby affecting cardiac fibrosis. Our findings demonstrate that B4GALT5 promotes cardiac fibrosis through the Akt/GSK-3ß/ß-catenin pathway and reveal laminin as the target protein of B4GALT5.

UGCG modulates heart hypertrophy through B4GalT5-mediated mitochondrial oxidative stress and the ERK signaling pathway.

Mechanical pressure overload and other stimuli often contribute to heart hypertrophy, a significant factor in the induction of heart failure. The UDP-glucose ceramide glycosyltransferase (UGCG) enzyme plays a crucial role in the metabolism of sphingolipids through the production of glucosylceramide. However, its role in heart hypertrophy remains unknown. In this study, UGCG was induced in response to pressure overload in vivo and phenylephrine stimulation in vitro. Additionally, UGCG downregulation ameliorated cardiomyocyte hypertrophy, improved cardiomyocyte mitochondrial oxidative stress, and reduced the ERK signaling pathway. Conversely, UGCG overexpression in cardiomyocytes promoted heart hypertrophy development, aggravated mitochondrial oxidative stress, and stimulated ERK signaling. Furthermore, the interaction between beta-1,4-galactosyltransferase 5 (B4GalT5), which catalyses the synthesis of lactosylceramide, and UGCG was identified, which also functions as a synergistic molecule of UGCG. Notably, limiting the expression of B4GalT5 impaired the capacity of UGCG to promote myocardial hypertrophy, suggesting that B4GalT5 acts as an intermediary for UGCG. Overall, this study highlights the potential of UGCG as a modulator of heart hypertrophy, rendering it a potential target for combating heart hypertrophy.

Circadian Genes MBOAT2/CDA/LPCAT2/B4GALT5 in the Metabolic Pathway Serve as New Biomarkers of PACA Prognosis and Immune Infiltration.

Pancreatic cancer (PACA) is a highly malignant tumor with a poor prognosis. Recent studies have discovered substantial differences in the expression levels of several circadian genes in PACA samples compared to normal samples. The goal of this research was to find differentially expressed rhythm genes (DERGs) in PACA samples and determine their role in the development of PACA. A total of 299 DERGs were identified in PACA, including 134 downregulated genes and 165 upregulated genes. DERGs were significantly abundant in the metabolic pathway and immune response pathways, according to GO and KEGG analyses. Survival analyses showed that PACA patients who had higher expression levels of MBOAT2/CDA/LPCAT2/B4GALT5 had shorter overall survival times. Using cell assay verification, the mRNA levels of MBOAT2/CDA/LPCAT2/B4GALT5 in Patu-8988 and PNAC-1 cells were found to be significantly higher than those in HPDE6-C7 cells, which was in line with previous studies on PACA patient data. Through conducting univariate Cox analysis, it was determined that MBOAT2/CDA/LPCAT2/B4GALT5 expression, age and grade were all high-risk factors. The MBOAT2/CDA/LPCAT2/B4GALT5 genes were independently correlated with overall survival, according to the multivariate Cox analysis. The proportion of immune cells in PACA and normal samples significantly changed, according to the immune infiltration analysis. Furthermore, MBOAT2/CDA/LPCAT2/B4GALT5 expression levels were significantly related to the level of immune cell infiltration. The protein-protein interaction network of the MBOAT2/CDA/LPCAT2/B4GALT5 genes included 54 biological nodes and 368 interacting genes. In conclusion, the finding of these DERGs adds to the investigation of the molecular processes underlying the onset and progression of PACA. In the future, DERGs may serve as prognostic and diagnostic biomarkers as well as drug targets for chronotherapy in PACA patients.

Circ_0009910 sponges miR-491-5p to promote acute myeloid leukemia progression through modulating B4GALT5 expression and PI3K/AKT signaling pathway.

BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous group of leukemias with an overall poor prognosis. Circular RNAs (circRNAs) have been verified to play important regulatory roles in AML progression. However, the role and molecular mechanism of circ_0009910 in AML development have not be completely clarified. METHODS: The expression levels of circ_0009910, microRNA-491-5p (miR-491-5p), and ß-1, 4-galactosyltransferase 5 (B4GALT5) were measured by quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot. Cell proliferation and self-renewal ability were assessed via Cell Counting Kit-8 (CCK-8) and sphere formation assay. Cell cycle distribution and cell apoptosis were evaluated by flow cytometry. Caspase-3 activity was tested by Caspase-3 Activity Assay Kit. Western blot was used to examine the protein levels of autophagy-related markers and PI3K/AKT pathway-related markers. The interaction between miR-491-5p and circ_0009910 or B4GALT5 was confirmed by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay, or RNA pull-down assay. RESULTS: Circ_0009910 was highly expressed in AML tissues and cells. Silenced circ_0009910 could significantly inhibit the proliferation, sphere formation, and autophagy and promoted the apoptosis of AML cells. Circ_0009910 bound to miR-491-5p in AML cells, and circ_0009910 promoted AML progression partly through sponging miR-491-5p in vitro. B4GALT5 was a target of miR-491-5p, and miR-491-5p overexpression-mediated influences in AML cells were effectually overturned by the addition of B4GALT5 overexpression plasmid. Furthermore, circ_0009910 could regulate the expression of B4GALT5 by downregulating miR-491-5p in AML cells. Additionally, circ_0009910 could activate the PI3K/AKT signaling pathway by sponging miR-491-5p. CONCLUSION: Circ_0009910 could suppress the proliferation, sphere formation, and autophagy and accelerated apoptosis by modulating B4GALT5 expression and activating the PI3K/AKT signaling pathway via sponging miR-491-5p in AML cells, suggesting that circ_0009910 might be a potential biomarker for the treatment of AML.

Adipocytes harbor a glucosylceramide biosynthesis pathway involved in iNKT cell activation.

BACKGROUND: Natural killer T (NKT) cells in adipose tissue (AT) contribute to whole body energy homeostasis. RESULTS: Inhibition of the glucosylceramide synthesis in adipocytes impairs iNKT cell activity. CONCLUSION: Glucosylceramide biosynthesis pathway is important for endogenous lipid antigen activation of iNKT cells in adipocytes. SIGNIFICANCE: Unraveling adipocyte-iNKT cell communication may help to fight obesity-induced AT dysfunction. Overproduction and/or accumulation of ceramide and ceramide metabolites, including glucosylceramides, can lead to insulin resistance. However, glucosylceramides also fulfill important physiological functions. They are presented by antigen presenting cells (APC) as endogenous lipid antigens via CD1d to activate a unique lymphocyte subspecies, the CD1d-restricted invariant (i) natural killer T (NKT) cells. Recently, adipocytes have emerged as lipid APC that can activate adipose tissue-resident iNKT cells and thereby contribute to whole body energy homeostasis. Here we investigate the role of the glucosylceramide biosynthesis pathway in the activation of iNKT cells by adipocytes. UDP-glucose ceramide glucosyltransferase (Ugcg), the first rate limiting step in the glucosylceramide biosynthesis pathway, was inhibited via chemical compounds and shRNA knockdown in vivo and in vitro. ß-1,4-Galactosyltransferase (B4Galt) 5 and 6, enzymes that convert glucosylceramides into potentially inactive lactosylceramides, were subjected to shRNA knock down. Subsequently, (pre)adipocyte cell lines were tested in co-culture experiments with iNKT cells (IFNγ and IL4 secretion). Inhibition of Ugcg activity shows that it regulates presentation of a considerable fraction of lipid self-antigens in adipocytes. Furthermore, reduced expression levels of either B4Galt5 or -6, indicate that B4Galt5 is dominant in the production of cellular lactosylceramides, but that inhibition of either enzyme results in increased iNKT cell activation. Additionally, in vivo inhibition of Ugcg by the aminosugar AMP-DNM results in decreased iNKT cell effector function in adipose tissue. Inhibition of endogenous glucosylceramide production results in decreased iNKT cells activity and cytokine production, underscoring the role of this biosynthetic pathway in lipid self-antigen presentation by adipocytes.

The Immunological Regulation Roles of Porcine ß-1, 4 Galactosyltransferase V (B4GALT5) in PRRSV Infection.

B4GALT5, also known as ß-1, 4 galactosyltransferase V, is one of the members of ß-1, 4 galactosyltransferase gene (B4GALT) family, which was concerned with embryonic development, tumor generation, other malignant diseases. In this study, we firstly cloned porcine B4GALT (pB4GALT5) from porcine alveolar macrophages, and predicted the structural domain and function of seven porcine ß-1, 4 galactosyltransferase (I-VII) based on transcriptome analysis of PRRSV infected cells. Additionally, the upregulated porcine B4GALT5 expression was detected from PRRSV infected porcine alveolar macrophage (PAM) cells. The PRRSV proliferation were slightly inhibited in overexpression of pB4GALT5 transfected cells, the interaction of B4GALT5 and GP5 of PRRSV was firstly be detected by Co-IP, and the co-location between B4GALT5 and GP5 were also observed in golgi membranes by confocal microscopy. A significant increasing mRNA transcription, including inflammatory cytokines (IFN-α, IL-6, IL-18, IL-1ß, TNF-α) and some cell surface glycosylated protein involved in antigen present (MHC-I/II), cell adhesion and migration (chemokine MCP-1 and receptor CCR2; LFA-1, ICAM-1) were upregulated in B4GALT5 overexpressed PRRSV infected cells. Our results demonstrated that the regulation of pB4GALT5 plays an important roles in PRRSV proliferation and modification function in viral infection cells. And these results will make achievements by supporting the research of latent mechanisms of ß-1, 4 galactosyltransferase V in antiviral immunity.