Nuclear localization of endothelial nitric oxide synthase and nitric oxide production attenuates aphidicolin-induced endothelial cell death

Jung Hyun Park, Du Hyong Cho, Yun Jin Hwang, Young Min Choi, Jee Young Lee, Inho Jo

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1 Scopus citations


Aphidicolin represses DNA replication by inhibiting DNA polymerase α and δ, which leads to cell cycle arrest and cell damage. Nitric oxide (NO) generated by endothelial NO synthase (eNOS) plays an essential role in maintenance of endothelial integrity including endothelial cell (EC) survival. Previously, we reported that aphidicolin increases NO production in bovine aortic ECs (BAECs). However, the role of aphidicolin-induced NO on EC viability and its molecular mechanism remain to be elucidated. Treatment with 20 μM aphidicolin for 24 h reduced BAEC viability by ~40%, which was accompanied by increased NO production, phosphorylation of eNOS at Ser1179 (p-eNOS-Ser1179), and eNOS protein expression. The aphidicolin-increased eNOS expression and p-eNOS-Ser1179 were not altered by 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N'-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA-AM), a cell permeable and specific intracellular Ca2+ chelator. Co-treatment with 2-phenyl-4, 4, 5, 5,-tetramethylimidazoline-1-oxyl 3-oxide (PTIO), an NO scavenger, or Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME), a NOS inhibitor, exacerbated aphidicolin-stimulated BAEC death. Knockdown of eNOS gene expression using siRNA aggravated aphidicolin-induced BAEC death. However, exogenous NO donors including S-nitroso-L-glutathione (GSNO) or diethylenetriamine NONOate (DETA NO) had no effect on aphidicolin-decreased BAEC viability and aggravated BAEC viability at higher doses. Interestingly, aphidicolin accumulated eNOS protein in the active form, p-eNOS-Ser1179, in the nucleus. When cells were ectopically transfected with a wild-type (WT)-eNOS gene, aphidicolin induced significant localization of the protein product in the nucleus. Additionally, aphidicolin-elicited cell death was significantly reversed in WT-eNOS gene-transfected BAECs. Furthermore, overexpression of the eNOS gene containing nuclear localization signal (NLS) but not nuclear export signal (NES) significantly attenuated aphidicolin-induced BAEC death. When G2A-eNOS mutant lacking myristoylation at Gly2 was transfected, its intracellular distribution became diffuse and included the nucleus. Finally, expression of N-myristoyltransferase 2 (NMT2) but not NMT1 significantly decreased in aphidicolin-treated BAECs. Taken together, our results suggest that aphidicolin attenuates BAEC death in part by increasing nuclear eNOS localization and NO production.

Original languageEnglish
Pages (from-to)12-19
Number of pages8
JournalNitric Oxide - Biology and Chemistry
StatePublished - 1 May 2021

Bibliographical note

Funding Information:
This work was supported by National Research Foundation grants ( 2018R1A2B2002062 , 2018R1D1A1B07050732 , and 2017R1D1A1B03034131 ) from the Korean government and by an RP-Grant in 2017 from Ewha Womans University .

Publisher Copyright:
© 2021 Elsevier Inc.


  • Aphidicolin
  • Endothelial cell death
  • NO
  • Nucleus
  • eNOS


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