Abstract:Biotransformation of glucose in organs includes multiple pathways, while quantitative evaluation of percentages of its utilization for individual pathways and their spatial heterogeneity in vivo remain unknown. Imaging MS (IMS) and metabolomics combined with a focused microwave irradiation for rapidly fixing tissue metabolism allowed us to quantify and visualize metabolic fluxes of glucose-derived metabolites in the mouse brain in vivo. At 15 min after the intraperitoneal injection of (13) C6 -labeled glucose,… Show more
“…We investigated the distribution of lactate within E9.5 embryos using matrix-assisted laser desorption/ ionization-imaging mass spectrometry (MALDI-IMS), a useful method for visualizing the spatial distribution of individual biomolecules at a spatial resolution of ∼30 µm pitch on intact tissues (Bailey et al, 2015;Hamilton et al, 2015;Sugiura et al, 2014). Fresh frozen embryos were sectioned and analyzed by MALDI-IMS.…”
Section: Transition Of Embryonic Metabolome Profiles During Cbmentioning
Adapting the energy metabolism state to changing bioenergetic demands is essential for mammalian development accompanying massive cell proliferation and cell differentiation. However, it remains unclear how developing embryos meet the changing bioenergetic demands during the chorioallantoic branching (CB) stage, when the maternal-fetal exchange of gases and nutrients is promoted. In this study, using metabolome analysis with mass-labeled glucose, we found that developing embryos redirected glucose carbon flow into the pentose phosphate pathway via suppression of the key glycolytic enzymes PFK-1 and aldolase during CB. Concomitantly, embryos exhibited an increase in lactate pool size and in the fractional contribution of glycolysis to lactate biosynthesis. Imaging mass spectrometry visualized lactate-rich tissues, such as the dorsal or posterior neural tube, somites and head mesenchyme. Furthermore, we found that the heterochronic gene Lin28a could act as a regulator of the metabolic changes observed during CB. Perturbation of glucose metabolism rewiring by suppressing Lin28a downregulation resulted in perinatal lethality. Thus, our work demonstrates that developing embryos rewire glucose metabolism following CB for normal development.
“…We investigated the distribution of lactate within E9.5 embryos using matrix-assisted laser desorption/ ionization-imaging mass spectrometry (MALDI-IMS), a useful method for visualizing the spatial distribution of individual biomolecules at a spatial resolution of ∼30 µm pitch on intact tissues (Bailey et al, 2015;Hamilton et al, 2015;Sugiura et al, 2014). Fresh frozen embryos were sectioned and analyzed by MALDI-IMS.…”
Section: Transition Of Embryonic Metabolome Profiles During Cbmentioning
Adapting the energy metabolism state to changing bioenergetic demands is essential for mammalian development accompanying massive cell proliferation and cell differentiation. However, it remains unclear how developing embryos meet the changing bioenergetic demands during the chorioallantoic branching (CB) stage, when the maternal-fetal exchange of gases and nutrients is promoted. In this study, using metabolome analysis with mass-labeled glucose, we found that developing embryos redirected glucose carbon flow into the pentose phosphate pathway via suppression of the key glycolytic enzymes PFK-1 and aldolase during CB. Concomitantly, embryos exhibited an increase in lactate pool size and in the fractional contribution of glycolysis to lactate biosynthesis. Imaging mass spectrometry visualized lactate-rich tissues, such as the dorsal or posterior neural tube, somites and head mesenchyme. Furthermore, we found that the heterochronic gene Lin28a could act as a regulator of the metabolic changes observed during CB. Perturbation of glucose metabolism rewiring by suppressing Lin28a downregulation resulted in perinatal lethality. Thus, our work demonstrates that developing embryos rewire glucose metabolism following CB for normal development.
“…Comparison of labile metabolites distributions using di erent sampling methods. 14) e FMW-treatment successfully suppressed these changes and resulted in high quality distribution images. (FMW; focused microwave irradiation, ISF; in-situ freezing, and PEF; posteuthanized freezing method)…”
Section: )mentioning
confidence: 99%
“…Quantitatively, the ATP concentration in the PEF treated tissue was dramatically decreased by 1/10 compared to that for FMW treated tissue. 14) TISSUE THICKNESS e thickness of tissue slices can be an important factor. Comparison of labile metabolites distributions using di erent sampling methods.…”
Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) can be used to visualize the distribution of biomolecules (proteins, peptides, metabolites) and drugs on tissue surfaces. In MALDI-IMS, sample preparation is crucial for successful results. A variety of conditions, such as tissue sampling methods, tissue thickness and matrix application procedure can have an impact on the results. In this review, we summarize each sample preparation step in an orderly sequence with practical examples. In addition, we discuss the importance of the organic solvent used in the matrix solution. e composition of the organic solvent used in the matrix solution is critical for achieving a high sensitivity in this procedure.
“…In one study, Sugiura et al, 26) we demonstrated that FMW treatment is an essential process for investigation of glucoseoriginated metabolic pathways in vivo using MS both for imaging and quanti cation.…”
Section: Fmw Is Essential For Analysis Of Glucose Metabolism In Vivo mentioning
confidence: 99%
“…In particular, we have developed several key techniques, including (i) a sample preparation procedure that eliminates the common e ect of postmortem (PM) degradation of labile metabolites, 26) and (ii) on-tissue derivatization of metabolites that could enhance the analyte ionization e ciency. 27) ese techniques have enabled visualization of diverse metabolite species, including not only abundant phospholipids [28][29][30] but also metabolites present in trace amounts such as minor amino acids, 31) nucleotides, 32,33) neurotransmitters, [34][35][36] and bioactive lipids, 37) in various tissues of diseased model animals (as summarized in Fig.…”
In vivo concentrations of cellular signaling mediators such as in ammatory mediators are normally maintained at very low levels due to their strong ability to induce a biological response. e production, di usion, and decomposition of such mediators are spatio-temporally regulated. erefore, in order to understand biochemical basis of disease progression and develop new therapeutic strategies, it is important to understand the spatiotemporal dynamics of the signaling mediators in vivo, during the progression of disorders, e.g., chronic in ammatory diseases; however, the lack of e ective imaging technology has made it di cult to determine their localizations in vivo. Such characterization requires technical breakthroughs, including molecular imaging methods that are sensitive enough to detect low levels of metabolites in the heterogeneous tissue regions in diseased organs. We and other groups have attempted to ll this technical gap by developing highly sensitive imaging mass spectrometry (IMS) technologies. To date, we have established two key techniques toward this goal, including (i) a sample preparation procedure that has eliminated the problem of the postmortem degradation of labile metabolites, and (ii) on-tissue derivatization of metabolites, which can enhance analyte ionization e ciency. Here, we review recent progress in the development of these technologies as well as how the highly sensitive IMS technique has contributed to increasing understanding of the biochemical basis of disease mechanisms, discovery of new diagnostic markers, and development of new therapies.Please cite this article as: Mass Spectrom (Tokyo) 2015; 4(1): A0040
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.