ACSL1, CH25H, GPCPD1, and PLA2G12A as the potential lipid-related diagnostic biomarkers of acute myocardial infarction.

Lipid metabolism plays an essential role in the genesis and progress of acute myocardial infarction (AMI). Herein, we identified and verified latent lipid-related genes involved in AMI by bioinformatic analysis. Lipid-related differentially expressed genes (DEGs) involved in AMI were identified using the GSE66360 dataset from the Gene Expression Omnibus (GEO) database and R software packages. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted to analyze lipid-related DEGs. Lipid-related genes were identified by two machine learning techniques: least absolute shrinkage and selection operator (LASSO) regression and support vector machine recursive feature elimination (SVM-RFE). The receiver operating characteristic (ROC) curves were used to descript diagnostic accuracy. Furthermore, blood samples were collected from AMI patients and healthy individuals, and real-time quantitative polymerase chain reaction (RT-qPCR) was used to determine the RNA levels of four lipid-related DEGs. Fifty lipid-related DEGs were identified, 28 upregulated and 22 downregulated. Several enrichment terms related to lipid metabolism were found by GO and KEGG enrichment analyses. After LASSO and SVM-RFE screening, four genes (ACSL1, CH25H, GPCPD1, and PLA2G12A) were identified as potential diagnostic biomarkers for AMI. Moreover, the RT-qPCR analysis indicated that the expression levels of four DEGs in AMI patients and healthy individuals were consistent with bioinformatics analysis results. The validation of clinical samples suggested that 4 lipid-related DEGs are expected to be diagnostic markers for AMI and provide new targets for lipid therapy of AMI.

Neutralizing properties of LY315920 toward snake venom group I and II myotoxic phospholipases A2.

A need exists to develop specific and clinically useful inhibitors of toxic enzymes present in snake venoms, responsible for severe tissue damage and life-threatening effects occurring in thousands of people suffering envenomations globally. LY315920 (Varespladib, S-5920, A-001), a low molecular weight drug developed to inhibit several human secreted phospholipases A2 (PLA2s), was recently shown to also inhibit PLA2s in whole snake venoms with high potency, yet no studies have examined its direct effect on purified snake venom PLA2s. This work evaluated the ability of LY315920 to neutralize the enzymatic and toxic activities of three isolated PLA2 toxins of structural groups I (pseudexin) and II (crotoxin B and myotoxin I), and their corresponding whole venoms. In vitro, LY315920 inhibited the catalytic activity of these three enzymes upon a synthetic substrate. The drug also blocked their cytotoxic effect on cultured murine myotubes. In mice, preincubation of the toxins or venoms with LY315920, followed by their intramuscular injection, resulted in significant inhibition of muscle damage. Finally, immediate, independent injection of LY315920 at the site of toxin or venom inoculation also resulted in a large reduction of myonecrosis in the case of pseudexin and myotoxin-I, and of Pseudechis colletti and Bothrops asper whole venoms, suggesting a possible method of drug delivery in emergency situations. Present findings add evidence to suggest the possibility of using LY315920 as a field antidote in snakebites, aiming to limit the myonecrosis induced by many venom PLA2s in the clinical setting.

CC-PLA2-1 and CC-PLA2-2, two Cerastes cerastes venom-derived phospholipases A2, inhibit angiogenesis both in vitro and in vivo.

Integrins are essential in the complex multistep process of angiogenesis and are thus attractive targets for the development of antiangiogenic therapies. Integrins are antagonized by disintegrins and C-type lectin-like proteins, two protein families from snake venom. Here, we report that CC-PLA2-1 and CC-PLA2-2, two novel secreted phospholipases A(2) (PLA(2)) isolated from Cerastes cerastes venom, also showed anti-integrin activity. Indeed, both PLA(2)s efficiently inhibited human brain microvascular endothelial cell adhesion and migration to fibrinogen and fibronectin in a dose-dependent manner. Interestingly, we show that this anti-adhesive effect was mediated by alpha5beta1 and alphav-containing integrins. CC-PLA2s also impaired in vitro human brain microvascular endothelial cell tubulogenesis on Matrigel and showed antiangiogenic activity in vivo in chicken chorioallantoic membrane assay. The complete PLA(2) cDNAs were cloned from a venom gland cDNA library. Mature CC-PLA2-1 and CC-PLA2-2 contain 121 and 120 amino acids, respectively, including 14 cysteines each and showed 83% identity. Tertiary model structures of CC-PLA2-1 and CC-PLA2-2 were generated by homology modeling. This is thus the first study describing an antiangiogenic effect for snake venom PLA(2)s and reporting first clues to their mechanism of action on endothelial cells.

Elapid venom toxins: multiple recruitments of ancient scaffolds.

Nigroxins A and B, two myotoxic phospholipases A2 (PLA2s) from the venom of the American elapid Micrurus nigrocinctus, belong to a new PLA2 subclass. Their primary structures were established and compared with those of PLA2s that have already been studied with respect to myotoxic activity. The combination of amino acid residues Arg15, Ala100, Asn108 and a hydrophobic residue at position 109 is present exclusively in class I PLA2s that display myotoxic activity. These residues cluster within a surface region rich in positive charges and are suggested to play a role in the interaction with the target membrane of the muscle fibers. It is concluded that the myotoxic PLA2s resulted from recruitment of an ancient scaffold. Dendrotoxins and alpha-neurotoxins are similarly derived from other old structures, which are, however, now also present in nontoxic proteins that are widely distributed throughout the animal kingdom. The evolutionary pathways by which elapid PLA2s acquired myotoxicity and dendrotoxins acquired K+-channel blocker activity are traced. They demonstrate how existing scaffolds were adapted stepwise to serve toxic functions by exchange of a few surface-exposed residues.