The ral exchange factor rgl2 promotes cardiomyocyte survival and inhibits cardiac fibrosis

Literature-Based Discovery to Elucidate the Biological Links between Resistant Hypertension and COVID-19

Multiple studies have reported new or exacerbated persistent or resistant hypertension in patients previously infected with COVID-19. We used literature-based discovery to identify and prioritize multi-scalar explanatory biology that relates resistant hypertension to COVID-19. Cross-domain text mining of 33+ million PubMed articles within a comprehensive knowledge graph was performed using SemNet 2.0. Unsupervised rank aggregation determined which concepts were most relevant utilizing the normalized HeteSim score. A series of simulations identified concepts directly related to COVID-19 and resistant hypertension or connected via one of three renin-angiotensin-aldosterone system hub nodes (mineralocorticoid receptor, epithelial sodium channel, angiotensin I receptor). The top-ranking concepts relating COVID-19 to resistant hypertension included: cGMP-dependent protein kinase II, MAP3K1, haspin, ral guanine nucleotide exchange factor, N-(3-Oxododecanoyl)-L-homoserine lactone, aspartic endopeptidases, metabotropic glutamate receptors, choline-phosphate cytidylyltransferase, protein tyrosine phosphatase, tat genes, MAP3K10, uridine kinase, dicer enzyme, CMD1B, USP17L2, FLNA, exportin 5, somatotropin releasing hormone, beta-melanocyte stimulating hormone, pegylated leptin, beta-lipoprotein, corticotropin, growth hormone-releasing peptide 2, pro-opiomelanocortin, alpha-melanocyte stimulating hormone, prolactin, thyroid hormone, poly-beta-hydroxybutyrate depolymerase, CR 1392, BCR-ABL fusion gene, high density lipoprotein sphingomyelin, pregnancy-associated murine protein 1, recQ4 helicase, immunoglobulin heavy chain variable domain, aglycotransferrin, host cell factor C1, ATP6V0D1, imipramine demethylase, TRIM40, H3C2 gene, COL1A1+COL1A2 gene, QARS gene, VPS54, TPM2, MPST, EXOSC2, ribosomal protein S10, TAP-144, gonadotropins, human gonadotropin releasing hormone 1, beta-lipotropin, octreotide, salmon calcitonin, des-n-octanoyl ghrelin, liraglutide, gastrins. Concepts were mapped to six physiological themes: altered endocrine function, 23.1%; inflammation or cytokine storm, 21.3%; lipid metabolism and atherosclerosis, 17.6%; sympathetic input to blood pressure regulation, 16.7%; altered entry of COVID-19 virus, 14.8%; and unknown, 6.5%.

Cytoprotective effects of the medicinal herb Astragalus membranaceus on lipopolysaccharide‑exposed cells

Astragalus membranaceus (AM) is a traditional Chinese medicinal herb, whose cytoprotective effects remain largely unknown. Here, the bacterial endotoxin lipopolysaccharide (LPS) was applied to a human pulmonary type II-like epithelial lung adenocarcinoma cell line, a human umbilical vein endothelial cell line, and a human bladder carcinoma cell line to construct in vitro models of intracellular oxidative stress. The authors assayed the cellular and mitochondrial cytoprotective effects of varying doses of AM root extract upon these cell lines. The cell lines were cultured as follows: LPS-only group, four LPS+AM groups treated with various AM concentrations plus LPS, and an untreated control group. Flow cytometry was used to assess apoptosis and cell cycle progression. A 2′,7′-dichlorofluorescein-diacetate assay was used to quantitate reactive oxygen species (ROS) generation. Mitochondrial membrane potential (Δψ_mit) was analyzed by Rhodamine 123 assay. Western blotting was performed to detect cleaved caspase-3, p53, and B cell lymphoma (Bcl)-2 levels. Across all cell lines, LPS significantly elevated apoptosis rates, shifted cells to S/G2 phase, increased ROS production, reduced Δψ_mit, upregulated cleaved caspase-3, upregulated p53, and downregulated Bcl-2 relative to controls (all P<0.05). As a general trend, increasing AM concentrations produced progressively greater reductions in the apoptosis rate, greater reductions in S/G2 phase %, greater reductions in ROS production, greater increases in Δψ_mit, greater reductions in cleaved caspase-3 and p53 expression, and greater increases in Bcl-2 expression. AM treatment protects human pulmonary and bladder epithelial cells, in addition to human endothelial cells, from LPS-induced apoptosis, in a dose-dependent manner.

DNA methylation patterns associated with oxidative stress in an ageing population

Background

Oxidative stress has been related to type 2 diabetes (T2D) and cardiovascular disease (CVD), the leading global cause of death. Contributions of environmental factors such as oxidative stress on complex traits and disease may be partly mediated through changes in epigenetic marks (e.g. DNA methylation). Studies relating differential methylation with intermediate phenotypes and disease endpoints may be useful in identifying additional candidate genes and mechanisms involved in disease.

Methods

To investigate the role of epigenetic variation in oxidative stress marker levels and subsequent development of CVD and T2D, we performed analyses of genome-wide DNA methylation in blood, ten markers of oxidative stress (total glutathione [TGSH], reduced glutathione [GSH], oxidised glutathione [GSSG], GSSG to GSH ratio, homocysteine [HCY], oxidised low-density lipoprotein (oxLDL), antibodies against oxLDL [OLAB], conjugated dienes [CD], baseline conjugated dienes [BCD]-LDL and total antioxidant capacity [TAOC]) and incident disease in up to 966 age-matched individuals.

Results

In total, we found 66 cytosine-guanine (CpG) sites associated with one or more oxidative stress markers (false discovery rate [FDR] <0.05). These sites were enriched in regulatory regions of the genome. Genes annotated to CpG sites showed enrichment in annotation clusters relating to phospho-metabolism and proteins with pleckstrin domains. We investigated the contribution of oxidative stress-associated CpGs to development of cardiometabolic disease. Methylation variation at CpGs in the 3'-UTR of HIST1H4D (cg08170869; histone cluster 1, H4d) and in the body of DVL1 (cg03465880; dishevelled-1) were associated with incident T2D events during 10 years of follow-up (all permutation p-values <0.01), indicating a role of epigenetic regulation in oxidative stress processes leading to development or progression of diabetes. Methylation QTL (meQTL) analysis showed significant associations with genetic sequence variants in cis at 28 (42%) of oxidative stress phenotype-associated sites (FDR < 0.05). Integrating cis-meQTLs with genotype-phenotype associations indicated that genetic effects on oxidative stress phenotype at one locus (cg07547695; BCL2L11) may be mediated through DNA methylation.

Conclusions

In conclusion, we report novel associations of DNA methylation with oxidative stress, some of which also show evidence of a relation with T2D incidence.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-016-0235-0) contains supplementary material, which is available to authorized users.