Activation of eNOS in endothelial cells exposed to ionizing radiation involves components of the DNA damage response pathway

Abstract

In this study, the involvement of ataxia telangiectasia mutated (ATM) kinase and heat shock protein 90 (HSP90) in endothelial nitric oxide synthase (eNOS) activation was investigated in X-irradiated bovine aortic endothelial cells. The activity of nitric oxide synthase (NOS) and the phosphorylation of serine 1179 of eNOS (eNOS-Ser1179) were significantly increased in irradiated cells. The radiation-induced increases in NOS activity and eNOS-Ser1179 phosphorylation levels were significantly reduced by treatment with either an ATM inhibitor (Ku-60019) or an HSP90 inhibitor (geldanamycin). Geldanamycin was furthermore found to suppress the radiation-induced phosphorylation of ATM-Ser1181. Our results indicate that the radiation-induced eNOS activation in bovine aortic endothelial cells is regulated by ATM and HSP90.

Differentiation of Human Induced Pluripotent or Embryonic Stem Cells Decreases the DNA Damage Repair by Homologous Recombination

“…There was no difference in the levels of DNA DSB damage induced by ionizing radiation between stem and differentiated cells, indicating that susceptibility to initial damage is independent of differentiation status ( Figure S1 C). Overall, these results are consistent with previous reports observed in various primary and cancer cells ( Fionda et al., 2015 , Nagane et al., 2015 , Oleson et al., 2014 ).

Figure 2 Nitric Oxide Induced Stem Cell Differentiation and DNA Damage Response (A) Partially differentiated cells (d7 EBs) were exposed to the NO donor NOC-18 (5 μM) on days 7, 9, 11, and 13, and the cells were harvested on day 14 for RNA sample analysis by real-time qPCR for NKx2.5.

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Sulfasalazine, an inhibitor of the cystine-glutamate antiporter, reduces DNA damage repair and enhances radiosensitivity in murine B16F10 melanoma

“…Western blotting was performed as previously described, with some modifications [ 13 ]. For B16F10 and MEF, cells were collected and lysed in modified RIPA buffer (50 mM Tris-HCl [pH 7.4], 150 mM NaCl, 1 mM ethylenediaminetetraacetic acid, 1% NP-40, 0.1% sodium dodecyl sulfate (SDS), 0.1% sodium deoxycholate, and protease inhibitor cocktail) following sonication using a Bioruptor UCD-200 (BM Equipment, Tokyo, Japan) at low intensity for 3 min.…”

Mechanisms for Radioprotection by Melatonin; Can it be Used as a Radiation Countermeasure?

“…NO can be produced by some types of nitric oxide synthases, including neuronal NOS (nNOS), endothelial NOS (eNOS) and iNOS [124]. However, studies have shown that iNOS is primarily responsible for NO production following exposure to IR [125,126]. After exposure to IR, NO can inhibit Ogg1 activity via nitrosylation of the zinc-finger motif of this enzyme [127,128].…”