Oxidation of Plasmalogen, Low-Density Lipoprotein and RAW 264.7 Cells by Photoactivatable Atomic Oxygen Precursors
摘要:
AbstractThe oxidation of lipids by endogenous or environmental reactive oxygen species (ROS) generates a myriad of different lipid oxidation products that have important roles in disease pathology. The lipid oxidation products obtained in these reactions are dependent upon the identity of the reacting ROS. The photoinduced deoxygenation of various aromatic heterocyclic oxides has been suggested to generate ground state atomic oxygen (O[3P]) as an oxidant; however, very little is known about reactions between lipids and O(3P). To identify lipid oxidation products arising from the reaction of lipids with O(3P), photoactivatable precursors of O(3P) were irradiated in the presence of lysoplasmenylcholine, low‐density lipoprotein and RAW 264.7 cells under aerobic and anaerobic conditions. Four different aldehyde products consistent with the oxidation of plasmalogens were observed. The four aldehydes were: tetradecanal, pentadecanal, 2‐hexadecenal and hexadecanal. Depending upon the conditions, either pentadecanal or 2‐hexadecenal was the major product. Increased amounts of the aldehyde products were observed in aerobic conditions.
Photoinduced DNA cleavage by atomic oxygen precursors in aqueous solutions
作者:James Korang、Ismaila Emahi、Whitney R. Grither、Sara M. Baumann、Dana A. Baum、Ryan D. McCulla
DOI:10.1039/c3ra41597j
日期:——
Reactive oxygen species are known to induce DNA strand cleavage and have been explored as treatments for cancer. The development of aqueous-soluble dibenzothiophene-S-oxide (DBTO) derivatives has made it possible to investigate the mechanism of DNA cleavage by these photoactivatable precursors of atomic oxygen. In addition to the release of atomic oxygen, DBTO can also undergo other processes such as α-cleavage. An objective of this work was to establish whether the extent of strand scission could be attributed to a direct reaction between atomic oxygen and DNA. To accomplish this aim, the extent of strand cleavage upon irradiation of three different DBTO derivatives was measured by the conversion of circular pUC19 plasmid (Form I) to nicked (Form II) as monitored by gel electrophoresis. The interaction of the sulfoxides with DNA was systematically studied by optical melt and fluorescence anisotropy experiments. Thiols are susceptible to rapid oxidation by atomic oxygen, and thus, glutathione was used as a ROS scavenger to determine if DNA cleavage was induced by the release of atomic oxygen. The results from these experiments indicated atomic oxygen was at least partially responsible for the observed strand scission.
Oxidation of Plasmalogen, Low-Density Lipoprotein and RAW 264.7 Cells by Photoactivatable Atomic Oxygen Precursors
作者:Max T. Bourdillon、Benjamin A. Ford、Ashley T. Knulty、Colleen N. Gray、Miao Zhang、David A. Ford、Ryan D. McCulla
DOI:10.1111/php.12201
日期:2014.3
AbstractThe oxidation of lipids by endogenous or environmental reactive oxygen species (ROS) generates a myriad of different lipid oxidation products that have important roles in disease pathology. The lipid oxidation products obtained in these reactions are dependent upon the identity of the reacting ROS. The photoinduced deoxygenation of various aromatic heterocyclic oxides has been suggested to generate ground state atomic oxygen (O[3P]) as an oxidant; however, very little is known about reactions between lipids and O(3P). To identify lipid oxidation products arising from the reaction of lipids with O(3P), photoactivatable precursors of O(3P) were irradiated in the presence of lysoplasmenylcholine, low‐density lipoprotein and RAW 264.7 cells under aerobic and anaerobic conditions. Four different aldehyde products consistent with the oxidation of plasmalogens were observed. The four aldehydes were: tetradecanal, pentadecanal, 2‐hexadecenal and hexadecanal. Depending upon the conditions, either pentadecanal or 2‐hexadecenal was the major product. Increased amounts of the aldehyde products were observed in aerobic conditions.
Photodeoxygenation of Dibenzothiophene <i>S</i>-Oxide Derivatives in Aqueous Media
作者:James Korang、Whitney R. Grither、Ryan D. McCulla
DOI:10.1021/ja100147b
日期:2010.3.31
Depending upon conditions, a variable amount of oxidation of the hydroxymethyl substituent into an aldehyde was observed to accompany deoxygenation. Analysis of the photoproducts indicated the deoxygenation occurred by at least two different pH-sensitive mechanisms. Underbasicconditions, photoinduced electron transfer yielding a hydroxysulfuranyl radical that decomposed by heterolytic S-O cleavage was thermodynamically
使用原子氧 (O((3)P)) 作为水中的强氧化剂一直缺乏简便、有效的来源。已建议将芳族亚砜光脱氧到有机溶剂中的相应硫化物,以低量子产率生产 O((3)P)。4,6-二羟甲基二苯并噻吩 S-氧化物和 2,8-二羟甲基二苯并噻吩 S-氧化物在水中的光解导致脱氧的量子产率明显高于有机溶剂。根据条件,观察到羟甲基取代基氧化成醛的变化量伴随脱氧。光产物的分析表明,脱氧作用是由至少两种不同的 pH 敏感机制引起的。在基本条件下,光致电子转移产生羟基硫烷基自由基,通过异裂 SO 裂解分解在热力学上是可行的。随着溶液的 pH 值降低,预计光致电子转移的热力学将变得越来越不利。因此,在中性和酸性 pH 值下,怀疑 SO 键断裂机制。观察到的光脱氧量子产率的增加与伴随 SO 键断裂的电荷分离一致。在有氧条件下烯烃的氧化裂解表明 O((3)P) 是在这些条件下的光解过程中产生的;然而,可能会形成离散的 O(*-)/HO(*),尤其是在低