Lewandowska Hanna, Meczyńska Sylwia, Sochanowicz Barbara, Sadło Jarosław, Kruszewski Marcin
Department of Radiobiology and Health Protection, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195, Warsaw, Poland.
J Biol Inorg Chem. 2007 Mar;12(3):345-52. doi: 10.1007/s00775-006-0192-8. Epub 2006 Nov 29.
Dinitrosyl non-heme-iron complexes (DNIC) are found in many nitric oxide producing tissues. A prerequisite of DNIC formation is the presence of nitric oxide, iron and thiol/imidazole groups. The aim of this study was to investigate the role of the cellular labile iron pool in the formation of DNIC in erythroid K562 cells. The cells were treated with a nitric oxide donor in the presence of a permeable (salicylaldehyde isonicotinoyl hydrazone) or a nonpermeable (desferrioxamine mesylate) iron chelator and DNIC formation was recorded using electron paramagnetic resonance. Both chelators inhibited DNIC formation up to 50% after 6 h of treatment. To further investigate the role of lysosomal iron in DNIC formation, we prevented lysosomal proteolysis by pretreatment of whole cells with NH4Cl. Pretreatment with NH4Cl inhibited the formation of DNIC in a time-dependent manner that points to the importance of the degradation of iron metalloproteins in DNIC formation in vivo. Fractionation of the cell content after treatment with the nitric oxide donor revealed that DNIC is formed predominantly in the endosomal/lysosomal fraction. Taken together, these data indicate that lysosomal iron plays a crucial role in DNIC formation in vivo. Degradation of iron-containing metalloproteins seems to be important for this process.
二亚硝酰基非血红素铁配合物（DNIC）存在于许多产生一氧化氮的组织中。DNIC形成的一个先决条件是存在一氧化氮、铁和硫醇/咪唑基团。本研究的目的是调查细胞内不稳定铁池在红系K562细胞中DNIC形成过程中的作用。在可渗透的（水杨醛异烟酰腙）或不可渗透的（甲磺酸去铁胺）铁螯合剂存在下，用一氧化氮供体处理细胞，并使用电子顺磁共振记录DNIC的形成。处理6小时后，两种螯合剂均将DNIC的形成抑制了50%。为了进一步研究溶酶体铁在DNIC形成中的作用，我们用NH4Cl对全细胞进行预处理，以防止溶酶体蛋白水解。用NH4Cl预处理以时间依赖性方式抑制了DNIC的形成，这表明铁金属蛋白的降解在体内DNIC形成过程中具有重要意义。用一氧化氮供体处理后对细胞内容物进行分级分离，结果显示DNIC主要在内体/溶酶体部分形成。综上所述，这些数据表明溶酶体铁在体内DNIC形成过程中起着关键作用。含铁金属蛋白的降解似乎对这一过程很重要。
