Simultaneous lipidomic and transcriptomic profiling in mouse brain punches of acute epileptic seizure model compared to controls

Abstract

In this study, we report the development of a dual extraction protocol for RNA and lipids, including phospholipids, endocannabinoids, and arachidonic acid, at high spatial resolution, e.g., brain punches obtained from whole frozen brains corresponding to four brain subregions: dorsal hippocampus, ventral hippocampus, basolateral amygdala, and hypothalamus. This extraction method combined with LC/multiple reaction monitoring for lipid quantifi-cation and quantitative PCR for RNA investigation allows lipidomic and transcriptomic profiling from submilligram amounts of tissue, thus benefiting the time and animal costs for analysis and the data reliability due to prevention of biological variability between animal batches and/or tissue heterogeneity, as compared with profiling in distinct animal batches. Moreover, the method allows a higher extraction efficiency and integrity preservation for RNA, while allowing concurrently quantitative analysis of low and high abundant lipids. The method was applied for brain punches obtained 1 h after kainic acid-induced epileptic seizures in mice (n = 10) compared with controls (n = 10), and enabled the provision of valuable new insights into the subregional lipid and RNA changes with epilepsy, highlighting its potential as a new viable tool in quantitative neurobiology.

Mice lacking L‐12/15‐lipoxygenase show increased mortality during kindling despite demonstrating resistance to epileptogenesis

“…First, it seems unlikely that a reduction in L‐12/15‐LO metabolite formation explains the increase in convulsive seizure threshold seen in the acute paradigm. High levels of the L‐12/15‐LO AA metabolites 12‐ and 15‐ hydroxyeicosatetraenoic acid (HETE) are produced in brain post‐seizure, suggesting that they might be anti‐ rather than pro‐seizure genic. Consistent with this notion is the observation that 12‐HETE reduces L‐ and N‐type Ca 2+ channel activity in rat cortical neurons and calcium accumulation in rat mossy fiber nerve endings .…”

“…Release of polyunsaturated fatty acids (PUFAs), including arachidonic acid (AA), from cell membranes stores is linked to excitatory neuronal activity, and this is increased markedly by aberrant epileptiform activity . AA is a substrate for major PUFA‐metabolizing enzymatic families including lipoxygenase (LO) and cyclooxygenase (COX), each of which catalyze its oxidation into eicosanoids—lipid mediators that act locally or distally to enact a broad range of physiological effects .…”

“…AA is a substrate for major PUFA‐metabolizing enzymatic families including lipoxygenase (LO) and cyclooxygenase (COX), each of which catalyze its oxidation into eicosanoids—lipid mediators that act locally or distally to enact a broad range of physiological effects . High levels of both COX and LO reaction products have been demonstrated in brain postseizure . As compared to COX [for review see], the role of LO and/or its metabolites in epilepsy and epileptogenesis has received little attention.…”

Recent advances in mass spectrometry imaging for multiomics application in neurology

“…MSI has been widely used in mapping lipids in mouse brain tissues, including fatty acids (Hirahara et al, ; Ibrahim et al, ; Lerner et al, ; Wu, Comi, Li, Rubakhin, & Sweedler, ; Zhou et al, ), ceramides (Barbacci et al, ; Muller et al, ; Nielsen et al, ; Woods et al, ), cardiolipins (Amoscato et al, ; Sparvero et al, ), phospholipids (Angel, Spraggins, Baldwin, & Caprioli, ; Guo et al, ; Hama et al, ; Hankin et al, ; Jadoul et al, ; Janfelt et al, ; Koizumi et al, ; Landgraf et al, ; Matsumoto et al, , ; Miyawaki et al, ; Shanta et al, ; Smith et al, ; Sparvero et al, ; Sugiura et al, ; Wang et al, ; Wang, Wang, & Han, ; Whitehead et al, ; Zaima et al, ), and sphingolipids (Caughlin et al, , ; Caughlin, Park, Yeung, Cechetto, & Whitehead, ; Chan et al, ; Dufresne et al, ; Ermini et al, ; Goto‐Inoue et al, ; Jackson et al, , ; Jones et al, ; Meriaux, Franck, Wisztorski, Salzet, & Fournier, ; Sugiura, Shimma, Konishi, Yamada, & Setou, ; Weishaupt, Caughlin, Yeung, & Whitehead, ; Whitehead et al, ). Gangliosides, amphipathic molecules composed of a ceramide lipid anchor linked to an oligosaccharide, are sialic acid‐containing glycosphingolipids and play numerous important roles in neuronal functions.…”

Mapping Molecular Datasets Back to the Brain Regions They are Extracted from: Remembering the Native Countries of Hypothalamic Expatriates and Refugees

“…Nakazawa et al (2013) [298] took the rather novel approach of performing both transcriptomics and peptidomics on separate sets of whole hypothalamic extracts (a “cross-omics” approach), and reported consensus results from both methods for oxytocin up-regulation in association with intracerebroventricular relaxin administration in rats. Recently, “cross-omics” approaches have been extended to combined transcriptomics/lipidomics of hypothalamus [252]. …”