LC/MS analysis of cardiolipins in substantia nigra and plasma of rotenone-treated rats: Implication for mitochondrial dysfunction in Parkinson's disease

Abstract

Exposure to rotenone in vivo results in selective degeneration of dopaminergic neurons and development of neuropathological features of Parkinson's disease. As rotenone acts as an inhibitor of mitochondrial respiratory complex I, we employed oxidative lipidomics to assess oxidative metabolism of a mitochondria-specific phospholipid, cardiolipin, in substantia nigra of exposed animals. We found a significant reduction of oxidizable PUFA-containing cardiolipin molecular species. We further revealed increased contents of mono-oxygenated cardiolipin species at late stages of the exposure. Notably, linoleic acid in sn-1 position was the major oxidation substrate yielding its mono-hydroxy- and epoxy-derivatives whereas more readily “oxidizable” fatty acid residues (arachidonic, docosahexaenoic acids) – remained non-oxidized. Elevated levels of PUFA cardiolipins were detected in plasma of rats exposed to rotenone. Characterization of oxidatively modified cardiolipin molecular species in substantia nirga and detection of PUFA-containing cardiolipin species in plasma may contribute to better understanding of the Parkinson's disease pathogenesis and lead to the development of new biomarkers of mitochondrial dysfunction associated with this disease.

Known unknowns of cardiolipin signaling: The best is yet to come

“…Recent developments in accurate mass and high sensitivity MS further expands the limits for identification and quantification of low abundance CL species in plasma and oxidized CL species in tissues [32, 41]. As an example, a newly developed Tribrid™ Ion-trap/Orbitrap™ technology (Fusion-Lumos, ThermoFisher Scientific) allows for unequivocal structural characterization of very low abundance oxidation products of CL with identification of the positions of oxygen-containing group in the fatty acyls in MS 3 spectra (Fig.…”

“…Intriguingly, a very high level of phospholipid specificity has been discovered as one of the most characteristic features of oxidation reactions triggered by these very different stimuli in different tissues with the common denominator – massive apoptosis. Mitochondrial CLs were found universally and most abundantly oxidized during injury associated with these insults [25, 41, 77, 80, 158]. Strikingly, CL oxidation turned to be non-random as well but had a pronounced specificity unrelated to the pattern of CL polyunsaturation.…”

“…Figure 1 compares the diversification and the preponderance of different molecular species of CL in the fish and bovine heart. The fish has a CL hetero-acylation that more closely resembles the diverse range of CL seen in the mammalian brain – which has the highest tissue diversification in mammalian tissues [39-41]. The enormous diversity of Cls in the heart of a fish (Northern Red Snapper) contrasts with extremely high dominance of homo-acylated tetralinoleoyl-CL in the bovine heart.…”

Therapies targeting lipid peroxidation in traumatic brain injury

“…Their short half-life makes them difficult to detect in biological samples. Nevertheless, recent developments in mass spectrometry-based oxidative lipidomics approaches make it possible to detect phospholipid hydroperoxides in plasma and tissue samples (Ji et al, 2012a); (Tyurin et al, 2010; Tyurina et al, 2015). Using this oxidative lipidomics approach, we have shown that lipid peroxidation is a nonrandom event after experimental and clinical TBI, and it is most prominent in the mitochondria early after injury as cytochrome c-catalyzed cardiolipin oxidation (Bayir et al, 2007b; Ji et al, 2012a).…”

Mitochondrial Redox Opto-Lipidomics Reveals Mono-Oxygenated Cardiolipins as Pro-Apoptotic Death Signals

“…(b) Unigram frequencies of observed oxidized acyl chains upon apoptosis induction by different stimuli highlight mono-oxygenated C18:2 CL species. A, NAO-light (current work); B, actinomycin D (2012); 61 C, actinomycin D (2014); 19 D, controlled cortical impact; 19 E, gamma irradiation (2008); 22 F, gamma irradiation (2009); 57 G, gamma irradiation (2011, in vitro ); 22 H, gamma irradiation (2011, in vivo ); 22 I, hyperoxia; 60 J, mechanical injury; 58 K, actinomycin D (current work); L, rotenone (2013); 56 M, rotenone (2015); 62 N, staurosporine; 65 O, single walled carbon nanotubes; 63 and P, whole body radiation. 19 In the inset boxplot, the same frequencies are shown by grouping the stimuli as follows: NAO-light (this work) in red, in vitro (B, C, F, G, J, K, L, and N) in blue, and in vivo (D, E, H, I, M, O, and P) in green.…”