A06 - Linking lipid metabolism to inflammation in models of demyelinating injury

https://rdp.sfb274.de/ (Research Data Platform) https://gepris.dfg.de/gepris/projekt/408885537 (DFG Gepris entry) The central nervous system (CNS) is a terminally differentiated tissue, where any insult carries a heightened risk - yet the tissue response to these insults is variable and can range from irreversible destruction to almost complete recovery. The rules that instruct these divergent outcomes are still unknown. The aim of this CRC is therefore to understand the biology of the multicellular ...

After demyelinating injury of the central nervous system, resolution of the mounting acute inflammation is crucial for the initiation of a regenerative response. Here, we aim to identify fatty acids and lipid mediators that govern the balance of inflammatory reactions within demyelinating lesions. Using lipidomics, we identify bioactive lipids in the resolution phase of inflammation with markedly elevated levels of n-3 polyunsaturated fatty acids. Using fat-1 transgenic mice, which convert n-6 ...

Understanding the complexity of cellular function within a tissue necessitates the combination of multiple phenotypic readouts. Here, we developed a method that links spatially-resolved gene expression of single cells with their ultrastructural morphology by integrating multiplexed error-robust fluorescence in situ hybridization (MERFISH) and large area volume electron microscopy (EM) on adjacent tissue sections. Using this method, we characterized in situ ultrastructural and transcriptional ...

Oligodendrocytes extend numerous cellular processes that wrap multiple times around axons to generate lipid-rich myelin sheaths. Myelin biogenesis requires an enormously productive biosynthetic machinery for generating and delivering these large amounts of newly synthesized lipids. Yet, a complete understanding of this process remains elusive. Utilizing volume electron microscopy, we demonstrate that the oligodendroglial endoplasmic reticulum (ER) is enriched in developing myelin, extending into ...

Corpus callosum dissections were lysed in 300 µL STET lysis buffer (1% (v/v) Triton X-100, 150 mM NaCl, 2 mM EDTA, 50 mM TrisHCl pH 7.5) with a Precellys Evolution homogenizer (Bertin, Germany) using 0.5 mL soft tissue homogenization kit CK14 applying two cycles of 30 s with a speed of 6500rpm. After 15 min incubation on ice, samples were centrifuged at 16,000×g for 15 min to remove undissolved material and cell debris. The supernatant was transferred to a fresh protein lobind tube (Eppendorf, ...

After demyelinating injury of the central nervous system, resolution of the mounting acute innate inflammation is crucial for the initiation of a regenerative response. To identify factors in lesion recovery after demyelination injury, we used a toxin-induced model, in which a single dose of lysolecithin is injected into the corpus callosum to induce a focal demyelinating lesion. Afterwards, we investigated the proteome of demyelinating lesions at different time points post injection (dpi) in a ...

Current spatial transcriptomics methods provide molecular and spatial information but no morphological readout. Here, we present STEM - a method that correlates multiplexed error-robust FISH with electron microscopy from neighboring tissue sections of the same sample. STEM links transcriptional and spatial organization of single cells with ultrastructural morphology of the tissue in vivo. Using STEM to characterize demyelinated white-matter lesions allowed us to link morphology of myelin-laden ...

Tryptic in solution digestion of the purified myelin fraction was performed according to the filter-aided sample preparation (FASP) protocol (Erwig et al., 2019) originally described by Manza et al., 2005; followed by LC-MS-analysis. In brief, purified myelin fractions corresponding to 10 µg myelin protein were dissolved and lysed in lysis buffer (1% ASB-14, 7 M urea, 2 M thiourea. 10 mM DTT 0.1 M Tris pH 8.5). Homogenised samples were diluted with lysis buffer containing 2% CHAPS to reduce ASB-14 ...