title: Punicalagin exerts protective effect against high glucose-induced cellular stress and neural tube defects.
abstract: 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.
authors.affiliation: Department of Obstetrics, Gynecology & Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Jianxiang
authors.initials: J
authors.lastname: Zhong
authors.affiliation: Department of Obstetrics, Gynecology & Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: E Albert
authors.initials: EA
authors.lastname: Reece
authors.affiliation: Department of Obstetrics, Gynecology & Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA. Electronic address: pyang@upi.umaryland.edu.
authors.forename: Peixin
authors.initials: P
authors.lastname: Yang
mesh_terms: D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D020169:Caspases / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian / Q000187:drug effects; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D005947:Glucose; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D047348:Hydrolyzable Tannins / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D054259:Neural Tube / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D009436:Neural Tube Defects / Q000139:chemically induced / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D018384:Oxidative Stress / Q000187:drug effects*; D010766:Phosphorylation; D011247:Pregnancy; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D000071701:Regulatory Factor X Transcription Factors; D051742:Transcription Factor CHOP / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D000071717:X-Box Binding Protein 1; D019892:eIF-2 Kinase / Q000235:genetics / Q000378:metabolism
chemical_list: D000447:Aldehydes; D000975:Antioxidants; D020169:Caspases; D004268:DNA-Binding Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; D004722:Endoribonucleases; D015852:Eukaryotic Initiation Factor-2; D005947:Glucose; D006360:Heat-Shock Proteins; D047348:Hydrolyzable Tannins; D017346:Protein Serine-Threonine Kinases; D000071701:Regulatory Factor X Transcription Factors; D051742:Transcription Factor CHOP; D014157:Transcription Factors; D000071717:X-Box Binding Protein 1; D019892:eIF-2 Kinase; C497250:Ddit3 protein, mouse; C000605544:Xbp1 protein, mouse; C115642:punicalagin; C510185:Ern1 protein, mouse; C027576:4-hydroxy-2-nonenal
keywords: Caspase activation; Endoplasmic reticulum stress; High glucose; Neural tube defects; Oxidative stress; Punicalagin