4-hydroxy-2-nonenal and Neural-Tube-Defects

Maternal diabetes-induced birth defects remain a significant health problem. Studying the effect of natural compounds with antioxidant properties and minimal toxicities on diabetic embryopathy may lead to the development of new and safe dietary supplements. Punicalagin is a primary polyphenol found in pomegranate juice, which possesses antioxidant, anti-inflammatory and anti-tumorigenic properties, suggesting a protective effect of punicalagin on diabetic embryopathy. Here, we examined whether punicalagin could reduce high glucose-induced neural tube defects (NTDs), and if this rescue occurs through blockage of cellular stress and caspase activation. Embryonic day 8.5 (E8.5) mouse embryos were cultured for 24 or 36 h with normal (5 mM) glucose or high glucose (16.7 mM), in presence or absence of 10 or 20 μM punicalagin. 10 μM punicalagin slightly reduced NTD formation under high glucose conditions; however, 20 μM punicalagin significantly inhibited high glucose-induced NTD formation. Punicalagin suppressed high glucose-induced lipid peroxidation marker 4-hydroxynonenal, nitrotyrosine-modified proteins, and lipid peroxides. Moreover, punicalagin abrogated endoplasmic reticulum stress by inhibiting phosphorylated protein kinase ribonucleic acid (RNA)-like ER kinase (p-PERK), phosphorylated inositol-requiring protein-1α (p-IRE1α), phosphorylated eukaryotic initiation factor 2α (p-eIF2α), C/EBP-homologous protein (CHOP), binding immunoglobulin protein (BiP) and x-box binding protein 1 (XBP1) mRNA splicing. Additionally, punicalagin suppressed high glucose-induced caspase 3 and caspase 8 cleavage. Punicalagin reduces high glucose-induced NTD formation by blocking cellular stress and caspase activation. These observations suggest punicalagin supplements could mitigate the teratogenic effects of hyperglycemia in the developing embryo, and possibly prevent diabetes-induced NTDs.

Topics: Aldehydes; Animals; Antioxidants; Caspases; DNA-Binding Proteins; Dose-Response Relationship, Drug; eIF-2 Kinase; Embryo, Mammalian; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Endoribonucleases; Eukaryotic Initiation Factor-2; Female; Gene Expression Regulation; Glucose; Heat-Shock Proteins; Hydrolyzable Tannins; Lipid Peroxidation; Mice; Mice, Inbred C57BL; Neural Tube; Neural Tube Defects; Oxidative Stress; Phosphorylation; Pregnancy; Protein Serine-Threonine Kinases; Regulatory Factor X Transcription Factors; Transcription Factor CHOP; Transcription Factors; X-Box Binding Protein 1

Copper-deficient rat embryos are characterized by brain and heart anomalies, low superoxide dismutase activity, and high superoxide anion concentrations. One consequence of increased superoxide anions can be the formation of peroxynitrite, a strong biological oxidant. To investigate developmentally important features of copper deficiency, GD 8.5 mouse embryos from copper-adequate and copper-deficient dams were cultured in media that were adequate or deficient in copper. After 48 h, copper-deficient embryos exhibited brain and heart anomalies, and a high incidence of yolk sac vasculature abnormalities compared to controls. Immunohistochemistry of 4-hydroxynonenal and 8-hydroxy-2'-deoxyguanosine for lipid and DNA damage, respectively, was similar between groups. In contrast, 3-nitrotyrosine, taken as a measure of protein nitration, was markedly higher in the neuroepithelium of the anterior neural tube of copper-deficient embryos than in controls. Repletion of copper-deficient media with copper, or supplementation with copper-zinc superoxide dismutase, Tiron, or glutathione peroxidase did not ameliorate the abnormal development, but did decrease 3-nitrotyrosine in neuroepithelium of copper-deficient embryos. These data support the concept that while copper deficiency compromises oxidant defense and increases protein nitration, additional mechanisms, e.g., altered nitric oxide metabolism may contribute to copper-deficiency-induced teratogenesis.

Topics: 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Brain; Copper; Deoxyguanosine; DNA Damage; Epithelium; Female; Fetal Development; Glutathione Peroxidase; Growth Inhibitors; Heart Defects, Congenital; Indicators and Reagents; Lipids; Mice; Neural Tube Defects; Peroxynitrous Acid; Pregnancy; Superoxide Dismutase; Superoxides; Tyrosine