Formation of molecular species of mitochondrial cardiolipin. 1. A novel transacylation mechanism to shuttle fatty acids between sn-1 and sn-2 positions of multiple phospholipid species

Lipids are critical for the regulation and control of cellular function, membrane dynamics, and signal transduction. The systematic identifi cation and analysis of all cellular lipids in a biological sample is embodied by the rapidly developing fi eld of lipidomics, which has been enabled by recent advances in mass spectrometry ( 1-3 ). A multidimensional MS-based shotgun lipidomics (MDMS-SL) approach for analysis of cellular lipidomes has been demonstrated as one of the most systematic and quantitative high-throughput platforms for global lipidomics capable of analyzing thousands of lipid molecular species directly from the lipid extracts of biological tissues ( 4, 5 ). Analysis of lipidomic data requires extensive use of bioinformatics and computational algorithms for the accurate identifi cation and quantifi cation of lipid molecular species and classes ( 5-9 ). However, most advances in bioinformatics in lipidomics have largely focused on lipid identifi cation rather than interpretation of alterations in biological function resulting in adaptive or pathologic changes in lipid metabolism ( 10 ). Thus, development of bioinformatic and systems biology approaches for the interpretation of lipidomic networks would signifi cantly advance the understanding of the roles of lipids in biological systems ( 3 ).Cardiolipin is a complex polyglycerophospholipid found almost exclusively in mitochondrial membranes of eukaryotic organisms ( 11 ). Cardiolipin is intricately involved in the effi cient production of ATP through utilizing the proton gradient as well as maintaining mitochondrial functionality ( 12-14 ). The diversity of cardiolipin molecular species varies markedly between tissues as well as among Abstract Cardiolipin is a class of mitochondrial specifi c phospholipid, which is intricately involved in mitochondrial functionality. Differences in cardiolipin species exist in a variety of tissues and diseases. It has been demonstrated that the cardiolipin profi le is a key modulator of the functions of many mitochondrial proteins. However, the chemical mechanism(s) leading to normal and/or pathological distribution of cardiolipin species remain elusive. Herein, we describe a novel approach for investigating the molecular mechanism of cardiolipin remodeling through a dynamic simulation. This approach applied data from shotgun lipidomic analyses of the heart, liver, brain, and lung mitochondrial lipidomes to model cardiolipin remodeling, including relative content, regiospecifi city, and isomeric composition of cardiolipin species. Generated cardiolipin profi les were nearly identical to those determined by shotgun lipidomics. Importantly, the simulated isomeric compositions of cardiolipin species were further substantiated through product ion analysis. Finally, unique enzymatic activities involved in cardiolipin remodeling were assessed from the parameters used in the dynamic simulation of cardiolipin profi les. Collectively, we described, verifi ed, and demonstrated a novel approach by integrating both lipidomic ana...

Section: Discussionsupporting

confidence: 80%

Dynamic simulation of cardiolipin remodeling: greasing the wheels for an interpretative approach to lipidomics

Kiebish

Bell

Yang

et al. 2010

“…This observation complements the well-established data linking morbidity and reduced CL by showing that there exists a range of mitochondrial changes in which CL undergoes a potentially compensatory response and a range (e.g., phosphatidylethanolamine and phosphatidylcholine) to MLCL via a phospholipid-lysophospholipid transacylase termed tafazzin (64)(65)(66)(67)(68)(69)(70).…”

Section: More Than a Target-regulated Response To Environmental Infl mentioning

confidence: 57%

Dietary macronutrients modulate the fatty acyl composition of rat liver mitochondrial cardiolipins

Stavrovskaya

Bird

Marur

et al. 2013

Supplementary key words mitochondria • ubiquinones • saturated fatty acids • trans fatty acids • monounsaturated fatty acids • polyunsaturated fatty acids • glycemic index • lipidomicsCardiolipins (CLs) are a subclass of phospholipids unique to mitochondria. Each CL is a dimeric phospholipid consisting of two phosphatidyl head groups, connected on a glycerol backbone, and four fatty acyl chains ( 1-3 ). Unlike most membrane phospholipids, CLs are predominantly found in the mitochondrial inner membrane and at contact sites between the inner and outer mitochondrial membrane. CLs comprise ‫ف‬ 25% of total phospholipids in the mitochondrial inner membrane ( 1-3 ). Mammalian CL has been reported to contain primarily ( ‫ف‬ 85%) 18:2 (linoleic) acyl side chains ( 2, 4, 5 ) that mediate the high affi nity of CL to inner mitochondrial membrane proteins ( 3, 6, 7 ).CLs play multiple key roles in the regulation of mitochondrial metabolism ( 2, 3, 8-10 ). These functions include maintenance of proper mitochondrial quaternary structure, regulation of essential enzymatic activities involved in electron transport and oxidative phosphorylation, and assembly of respiratory supercomplexes. In particular, CL is required for the proper functioning of mitochondrial respiratory complexes I, III, IV (cytochrome oxidase), ATP synthase ( 6,(11)(12)(13)(14)(15)(16)(17)(18)(19), cardiolipin synthase ( 20 ), and several transporters in the inner mitochondrial membrane [e.g., the ADP/ATP translocator ( 10, 18, 21 ), phosphate transporter ( 22 ), pyruvate transporter ( 23 ), and carnitine/ acylcarnitine carrier ( 24 )

“…MLCL and DLCL were further analyzed by 1 H-NMR and the spectra compared with previously reported results ( Fig. 5 ) ( 21 ). The peak at 5.0 ppm corresponds to the protons at the sn -2 position and shifts upfi eld with hydrolysis of the acyl chain.…”

Section: Downloaded Frommentioning

confidence: 99%

Monolysocardiolipin: improved preparation with high yield

Kim

Hoppel

2011

the sn -2 position. Because CL has two sn -2 acyl chains, the reaction preferentially generates dilysocardiolipin (DLCL) by hydrolyzing both sn -2 chains ( 9 ). Therefore, the yield of MLCL depends both on the reaction conditions and stopping the reaction when MLCL is at a maximum. Recently, Boldyrev et al. ( 18 ) reported preparing MLCL with a signifi cantly improved yield (39%), but the reaction procedure is complicated.A previous report mentioned using ethanol as solvent to make MLCL ( 19 ). Herein, we extend that report, describing a simple, high-yielding preparation of MLCL using methanol as the reaction solvent. DLCL also was prepared stoichiometrically in methanol. The synthesized MLCL and DLCL were fully characterized using ESI-MS/MS and NMR. EXPERIMENTAL PROCEDURES