Lysophosphatidic acid produced by hen egg white lysophospholipase D induces vascular development on extraembryonic membranes

Discovery of Spoilage Markers for Chicken Eggs Using Liquid Chromatography-High Resolution Mass Spectrometry-Based Untargeted and Targeted Foodomics

The current approaches remain insufficient for measuring chicken egg spoilage or present analytical limitations. This study aimed to complement the existing analyses and identify novel markers using liquid chromatography-high resolution mass spectrometry-based foodomics strategies. In the discovery set, comparative untargeted metabolomics was utilized to identify marker candidates in microbially inoculated chicken eggs. Markers were annotated by spectral matching with authentic standards, experimental libraries, or in silico fragmentation. In the validation set, targeted metabolomics was employed to verify the markers in stored chicken eggs from five farms. Statistical differences at a p-value < 0.001 revealed increases in lactic and 3-hydroxybutyric acids and decreases in phosphocholine, LPE(O-18:1), LPC(16:0), and LPC(18:0) in stored eggs. Receiver operating characteristic curve analysis of the six combined markers yielded an AUC of 0.956 and a sensitivity and specificity of ∼90%. Four phospholipids were highlighted as a novel class of spoilage markers. Our findings may contribute to further industrial implementation, benefiting the quality assurance and food safety of poultry egg production.

LPA receptor signaling: pharmacology, physiology, and pathophysiology

Lysophosphatidic acid (LPA) is a small ubiquitous lipid found in vertebrate and nonvertebrate organisms that mediates diverse biological actions and demonstrates medicinal relevance. LPA's functional roles are driven by extracellular signaling through at least six 7-transmembrane G protein-coupled receptors. These receptors are named LPA1-6 and signal through numerous effector pathways activated by heterotrimeric G proteins, including Gi/o, G12/13, Gq, and Gs LPA receptor-mediated effects have been described in numerous cell types and model systems, both in vitro and in vivo, through gain- and loss-of-function studies. These studies have revealed physiological and pathophysiological influences on virtually every organ system and developmental stage of an organism. These include the nervous, cardiovascular, reproductive, and pulmonary systems. Disturbances in normal LPA signaling may contribute to a range of diseases, including neurodevelopmental and neuropsychiatric disorders, pain, cardiovascular disease, bone disorders, fibrosis, cancer, infertility, and obesity. These studies underscore the potential of LPA receptor subtypes and related signaling mechanisms to provide novel therapeutic targets.

Evaluation of the in vivo antioxidative activity of redox nanoparticles by using a developing chicken egg as an alternative animal model

Antioxidants have been demonstrated to exert beneficial effects as pharmacotherapies for cardiovascular diseases. The in vitro systems generally employed to evaluate antioxidants, however, are limited by having no appreciable in vivo redox status of the antioxidants. Therefore, we used our developing chicken egg model to evaluate the in vivo antioxidative activity of a redox nanoparticle possessing 2,2,6,6-tetramethylpiperidine-1-oxyl (RNP(O)). The 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH) elicited strong oxidative stress and its LD50 value for chick embryos was 3.5±0.9mg/egg. The low molecular weight nitroxide compound, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL), which is known to have the highest level of antioxidant activity, showed no significant protective effect against AAPH-induced embryo lethality. On the contrary, RNP(O) had potent protective effects against AAPH-induced embryo lethality. Moreover, RNP(O) could significantly suppress the production of lipid peroxides in chick serum induced by hydrocortisone. Since RNP(O) has a longer retention time in blood than TEMPOL, RNP(O) may protect the embryo against lethal oxidative stress by suppressing lipid peroxidation. The validity of in vivo experiments using developing chicken eggs was supported by our data, where RNP(O) was determined to elicit strong antioxidative activity in vivo, irrespective of the lack of a significant difference in the in vitro activity between low-molecular weight TEMPOL and RNP(O). Our results support the use of the developing chicken egg model to evaluate the potential in vivo antioxidative activity of RNP(O).