Johanna von Gerichten

Dr Johanna von Gerichten


Postdoctoral Researcher
Analytical Chemistry, Lipid Analysis, Lipidomics, Mass Spectrometry, GC or LC-MS(/MS)

About

My qualifications

2012
B.Sc. Biological Chemistry
University of Applied Sciences Mannheim, Germany
2014
M.Sc. Biomedical Science and Technology
University of Applied Sciences Mannheim, Germany

Previous roles

01 July 2014 - 31 July 2018
PhD student - Development of Mass Spectrometric Methods for Tissue Imaging and LC-based Quantification of Glycosphingolipids/Gangliosides including Tay-Sachs disease based Neuraminidase-deficient Mouse Models and Human Gut Microbiota -
German Cancer Research Center (DKFZ), Heidelberg, Germany

Academic networks

    Publications

    C Paget , S Deng, D Soulard, D Priestman, S Speca, J von Gerichten, A Speak, A Saroha, Y Pewzner-Jung, A Futerman, T Mallevaey, C Faveeuw, X Gu, F Platt , R Sandhoff, F Trottein (2019) TLR9-mediated dendritic cell activation uncovers mammalian ganglioside species with specific ceramide backbones that activate invariant natural killer T cells
    CD1d-restricted invariant natural killer T (NKT) cells represent a heterogeneous population of lipid-reactive T cells that are involved in many immune responses, mediated through T-cell receptor (TCR)–dependent and/or independent activation. Although numerous microbial lipid antigens (Ags) have been identified, several lines of evidence have suggested the existence of relevant Ags of endogenous origin. However, the identification of their precise nature as well as the molecular mechanisms involved in their generation are still highly controversial and ill defined. Here, we identified two mammalian gangliosides—namely monosialoganglioside GM3 and disialoganglioside GD3—as endogenous activators for mouse NKT cells. These glycosphingolipids are found in Toll-like receptor-stimulated dendritic cells (DC) as several species varying in their -acyl fatty chain composition. Interestingly, their ability to activate NKT cells is highly dependent on the ceramide backbone structure. Thus, both synthetic GM3 and GD3 comprising a d18:1-C24:1 ceramide backbone were able to activate NKT cells in a CD1d-dependent manner. GM3 and GD3 are not directly recognized by the NKT TCR and required the Ag presenting cell intracellular machinery to reveal their antigenicity. We propose a new concept in which NKT cells can rapidly respond to pre-existing self-molecules after stress-induced structural changes in CD1d-expressing cells. Moreover, these gangliosides conferred partial protection in the context of bacterial infection. Thus, this report identified new biologically relevant lipid self-Ags for NKT cells.
    iiNiiiii
    I Morace, R Pilz, G Federico, R Jennemann, D Krunic, V Nordström, J von Gerichten, C Marsching, I Schießl, J Müthing, C Wunder, L Johannes, R Sandhoff, H-J Gröne (2019) Renal globotriaosylceramide facilitates tubular albumin absorption and its inhibition protects against acute kidney injury
    To elucidate the physiologic function of renal  (Gb3/CD77), which up-to-date has been associated exclusively with  binding, we have analyzed renal function in Gb3-deficient mice. Gb3  KO (Gb3S−/−) mice displayed an increased renal  and low molecular weight protein excretion compared to WT. Gb3 localized at the brush border and within vesicular structures in WT proximal tubules and has now been shown to be closely associated with the receptor complex megalin/cubilin and with albumin uptake. In two clinically relevant mouse models of  caused by  as seen in  and the  , Gb3S−/− mice showed a preserved renal function and morphology, compared to WT. Pharmacologic inhibition of glucosylceramide-based , including Gb3, in WT mice corroborated the results of genetically Gb3-deficient mice. In conclusion, our data significantly advance the current knowledge on the physiologic and pathophysiologic role of Gb3 in proximal tubules, showing an involvement in the reabsorption of filtered albumin, myoglobin and the aminoglycoside gentamicin.
    S Herzer, C Hagan, J von Gerichten, V Dieterle, B Munteanu, R Sandhoff, C Hopf and V Nordström (2018) Deletion of Specific Sphingolipids in Distinct Neurons Improves Spatial Memory in a Mouse Model of Alzheimer’s Disease
    Alzheimer’s disease (AD) is characterized by progressive neurodegeneration and a concomitant loss of synapses and cognitive abilities. Recently, we have proposed that an alteration of neuronal membrane lipid microdomains increases neuronal resistance toward amyloid-β stress in cultured neurons and protects from neurodegeneration in a mouse model of AD. Lipid microdomains are highly enriched in a specific subclass of glycosphingolipids, termed gangliosides. The enzyme glucosylceramide synthase (GCS) catalyzes the rate-limiting step in the biosynthesis of these gangliosides. The present work now demonstrates that genetic GCS deletion in subsets of adult forebrain neurons significantly improves the spatial memory and counteracts the loss of dendritic spines in the hippocampal dentate gyrus of 5x familial AD mice (5xFAD//f/f//Thy1-CreERT2//EYFP mice), when compared to 5xFAD//f/f littermates (5xFAD mice). Aberrantly activated glial cells and their expression of pro-inflammatory cytokines have emerged as the major culprits for synaptic loss in AD. Typically, astrocytic activation is accompanied by a thickening of astrocytic processes, which impairs astrocytic support for neuronal synapses. In contrast to 5xFAD mice, 5xFAD//f/f//Thy1-CreERT2//EYFP display a less pronounced thickening of astrocytic processes and a lower expression of tumor necrosis factor-α and interleukin 1-α in the hippocampus. Thus, this work further emphasizes that GCS inhibition may constitute a potential therapeutic target against AD.
    UgcgUgcgUgcg
    V Seyrantepe, S A Demir, Z K Timur, J Von Gerichten, C Marsching, E Erdemli, E Oztas, K Takahashi, K Yamaguchi, N A Buket, D Demir, T Dalkara, K Erich, C Hopf, R Sandhoff, T Miyagi (2018) Murine Sialidase Neu3 facilitates GM2 degradation and bypass in mouse model of Tay-Sachs disease
    Tay-Sachs disease is a severe  disorder caused by mutations in , the gene that encodes for the  of lysosomal  A (HEXA), which converts GM2 to . Unexpectedly, / mice have a normal  and show no obvious neurological impairment until at least one year of age. These mice catabolize stored  using sialidase(s) to remove  and form the  GA2, which is further processed by β-hexosaminidase B. Therefore, the presence of the  (s) allows the consequences of the  defect to be bypassed. To determine if the sialidase NEU3 contributes to GM2 ganglioside degradation, we generated a mouse model with combined deficiencies of HEXA and NEU3. The // mice were healthy at birth, but died at 1.5 to 4.5 months of age.  and  of the brains of // mice revealed the abnormal accumulation of GM2 ganglioside. Histological and immunohistochemical analysis demonstrated cytoplasmic  in the neurons. Electron microscopic examination of the brain, kidneys and  revealed pleomorphic inclusions of many small vesicles and complex lamellar structures. The // mice exhibited progressive  with neuronal loss, , and . Slow movement, ataxia, and tremors were the prominent neurological abnormalities observed in these mice. Furthermore, radiographs revealed abnormalities in the skeletal bones of the // mice. Thus, the // mice mimic the neuropathological and clinical abnormalities of the classical early-onset Tay-Sachs patients, and provide a suitable model for the future pre-clinical testing of potential treatments for this condition.
    J von Gerichten, K Schlosser, D Lamprecht, I Morace, M Eckhardt, D Wachten, R Jennemann, H-J Gröne, M Mack, and R Sandhoff (2017) Diastereomer-specific quantification of bioactive hexosylceramides from bacteria and mammals
    Mammals synthesize, cell-type specifically, the diastereomeric hexosylceramides, -galactosylceramide (GalCer) and -glucosylceramide (GlcCer), which are involved in several diseases, such as sphingolipidosis, diabetes, chronic kidney diseases, or cancer. In contrast, Bacteroides fragilis, a member of the human gut microbiome, and the marine sponge, Agelas mauritianus, produce -GalCer, one of the most potent stimulators for invariant natural killer T cells. To dissect the contribution of these individual stereoisomers to pathologies, we established a novel hydrophilic interaction chromatography-based LC-MS2 method and separated (R > 1.5) corresponding diastereomers from each other, independent of their lipid anchors. Testing various bacterial and mammalian samples, we could separate, identify (including the lipid anchor composition), and quantify endogenous -GlcCer, -GalCer, and -GalCer isomers without additional derivatization steps. Thereby, we show a selective decrease of -GlcCers versus -GalCers in cell-specific models of GlcCer synthase-deficiency and an increase of specific -GlcCers due to loss of -glucoceramidase 2 activity. Vice versa, -GalCer increased specifically when cerebroside sulfotransferase (Gal3st1) was deleted. We further confirm -GalCer as substrate of globotriaosylceramide synthase for galabiaosylceramide synthesis and identify additional members of the human gut microbiome to contain immunogenic -GalCers. Finally, this method is shown to separate corresponding hexosylsphingosine standards, promoting its applicability in further investigations
    A Fülöp, D S, K Erich, J von Gerichten, P van Hoogevest, R Sandhoff & C Hopf (2016) Molecular imaging of brain localization of liposomes in mice using MALDI mass spectrometry
    Phospholipids have excellent biocompatibility and are therefore often used as main components of liposomal drug carriers. In traditional bioanalytics, the  distribution of liposomal drug carriers is assessed using radiolabeled liposomal constituents. This study presents matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) as an alternative, label-free method for  molecular imaging of liposomal drug carriers in mouse tissue. To this end, indocyanine green as cargo and two liposomal markers, 1,2-dipalmitoyl--glycero-3-phosphoglycerol (DPPG) and 1,2-distearoyl--glycero-3-phosphoethanolamine conjugated with monodisperse polyethylene glycol (PEG36-DSPE) were incorporated into liposomal carriers and administered to mice. We used MALDI MSI of the two lipid markers in both positive and negative ion mode for visualization of liposome integrity and distribution in mouse organs. Additional MSI of hemoglobin in the same tissue slice and pixel-by-pixel computational analysis of co-occurrence of lipid markers and hemoglobin served as indicator of liposome localization either in parenchyma or in blood vessels. Our proof-of-concept study suggests that liposomal components and indocyanine green distributed into all investigated organs.
    in-vivoex-vivosnsn
    B. A. Fielding,P. C. Calder,N. A. Irvine,E. A. Miles,K. A. Lillycrop,J. von Gerichten,G. C. Burdge, (2019) How does polyunsaturated fatty acid biosynthesis regulate T-lymphocyte function?
    Impaired regulation of immune function characterised by chronic inflammation together with a declining protective immune response is a major challenge to healthy ageing. It is therefore important to understand the mechanisms that regulate immune function and the impact of ageing upon such processes. Appropriate induction and resolution of the immune response require adequate availability of polyunsaturated fatty acids (PUFAs) for incorporation into cell membranes. However, humans are unable to synthesise PUFAs  and are dependent upon dietary intake for pre-formed PUFAs or synthesis by the liver from the essential fatty acids, linoleic acid (LA, 18:2-6) and alpha-linolenic acid (aLNA, 18:3-3). We have shown that activation of peripheral blood mononuclear cells increases PUFA biosynthesis from essential fatty acids via a mechanism that involves altered epigenetic regulation of a key gene in the pathway. Moreover, induction of PUFA synthesis is directly involved in the regulation of lymphocyte activation and proliferation. The aim of the Biotechnology and Biological Sciences Research Council responsive mode award described in this paper, ‘How does polyunsaturated fatty acid biosynthesis regulate T-lymphocyte function?’, is to determine how PUFA biosynthesis regulates T-cell function and the effect of ageing on this process. The project will identify points of regulation in the biosynthetic pathway and how these might influence the capacity for up-regulation of PUFA synthesis in older individuals. We will use stable isotope tracers of LA and aLNA to determine whether newly synthesised PUFAs are preferential substrates for synthesis of lipid mediators and whether they are involved in formation of membrane microdomains that mediate cell signalling.
    de novonn
    Johanna von Gerichten, Annette L. West, Nicola A. Irvine, Elizabeth A. Miles, Philip C. Calder, Karen A. Lillycrop, Barbara A. Fielding, and Graham C. Burdge (2021) The Partitioning of Newly Assimilated Linoleic and α-Linolenic Acids Between Synthesis of Longer-Chain Polyunsaturated Fatty Acids and Hydroxyoctadecaenoic Acids Is a Putative Branch Point in T-Cell Essential Fatty Acid Metabolism
    Longer-chain polyunsaturated fatty acids (LCPUFAs) ≥20 carbons long are required for leukocyte function. These can be obtained from the diet, but there is some evidence that leukocytes can convert essential fatty acids (EFAs) into LCPUFAs. We used stable isotope tracers to investigate LCPUFA biosynthesis and the effect of different EFA substrate ratios in human T lymphocytes. CD3+ T cells were incubated for up to 48 h with or without concanavalin A in media containing a 18:2n-6:18:3n-3 (EFA) ratio of either 5:1 or 8:1 and [13C]18:3n-3 plus [d5]18:2n-6. Mitogen stimulation increased the amounts of 16:1n-7, 18:1n-9, 18:2n-6, 20:3n-6, 20:4n-6, 18:3n-3, and 20:5n-3 in T cells. Expression of the activation marker CD69 preceded increased  and  mRNA expression and increased amounts of [d5]20:2n-6 and [13C]20:3n-3 at 48 h. In addition, 22-carbon n-6 or n-3 LCPUFA synthesis was not detected, consistent with the absence of  expression. An EFA ratio of 8:1 reduced 18:3n-3 conversion and enhanced 20:2n-6 synthesis compared to a 5:1 ratio. Here, [d5]9- and [d5]-13-hydroxyoctadecadienoic (HODE) and [13C]9- and [13C]13-hydroxyoctadecatrienoic acids (HOTrE) were the major labelled oxylipins in culture supernatants; labelled oxylipins ≥20 carbons were not detected. An EFA ratio of 8:1 suppressed 9- and 13-HOTrE synthesis, but there was no significant effect on 9- and 13-HODE synthesis. These findings suggest that partitioning of newly assimilated EFA between LCPUFA synthesis and hydroxyoctadecaenoic acid may be a metabolic branch point in T-cell EFA metabolism that has implications for understanding the effects of dietary fats on T lymphocyte function.
    FADS2FADS1ELOVL2