TY - JOUR A1 - Majumder, Snigdha A1 - Jugovic, Isabelle A1 - Saul, Domenica A1 - Bell, Luisa A1 - Hundhausen, Nadine A1 - Seal, Rishav A1 - Beilhack, Andreas A1 - Rosenwald, Andreas A1 - Mougiakakos, Dimitrios A1 - Berberich-Siebelt, Friederike T1 - Rapid and Efficient Gene Editing for Direct Transplantation of Naive Murine Cas9\(^+\) T Cells JF - Frontiers in Immunology N2 - Gene editing of primary T cells is a difficult task. However, it is important for research and especially for clinical T-cell transfers. CRISPR/Cas9 is the most powerful gene-editing technique. It has to be applied to cells by either retroviral transduction or electroporation of ribonucleoprotein complexes. Only the latter is possible with resting T cells. Here, we make use of Cas9 transgenic mice and demonstrate nucleofection of pre-stimulated and, importantly, of naive CD3\(^+\) T cells with guideRNA only. This proved to be rapid and efficient with no need of further selection. In the mixture of Cas9\(^+\)CD3\(^+\) T cells, CD4\(^+\) and CD8\(^+\) conventional as well as regulatory T cells were targeted concurrently. IL-7 supported survival and naivety in vitro, but T cells were also transplantable immediately after nucleofection and elicited their function like unprocessed T cells. Accordingly, metabolic reprogramming reached normal levels within days. In a major mismatch model of GvHD, not only ablation of NFATc1 and/or NFATc2, but also of the NFAT-target gene IRF4 in naïve primary murine Cas9\(^+\)CD3\(^+\) T cells by gRNA-only nucleofection ameliorated GvHD. However, pre-activated murine T cells could not achieve long-term protection from GvHD upon single NFATc1 or NFATc2 knockout. This emphasizes the necessity of gene-editing and transferring unstimulated human T cells during allogenic hematopoietic stem cell transplantation. KW - CRISPR/Cas9 KW - gRNA-only KW - GvHD KW - metabolism KW - NFAT KW - naive T-cell gene editing KW - T-cell transfer KW - IRF4 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-242896 SN - 1664-3224 VL - 12 ER - TY - JOUR A1 - Zink, Miriam A1 - Seewald, Anne A1 - Rohrbach, Mareike A1 - Brodehl, Andreas A1 - Liedtke, Daniel A1 - Williams, Tatjana A1 - Childs, Sarah J. A1 - Gerull, Brenda T1 - Altered expression of TMEM43 causes abnormal cardiac structure and function in zebrafish JF - International Journal of Molecular Sciences N2 - Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disease caused by heterozygous missense mutations within the gene encoding for the nuclear envelope protein transmembrane protein 43 (TMEM43). The disease is characterized by myocyte loss and fibro-fatty replacement, leading to life-threatening ventricular arrhythmias and sudden cardiac death. However, the role of TMEM43 in the pathogenesis of ACM remains poorly understood. In this study, we generated cardiomyocyte-restricted transgenic zebrafish lines that overexpress eGFP-linked full-length human wild-type (WT) TMEM43 and two genetic variants (c.1073C>T, p.S358L; c.332C>T, p.P111L) using the Tol2-system. Overexpression of WT and p.P111L-mutant TMEM43 was associated with transcriptional activation of the mTOR pathway and ribosome biogenesis, and resulted in enlarged hearts with cardiomyocyte hypertrophy. Intriguingly, mutant p.S358L TMEM43 was found to be unstable and partially redistributed into the cytoplasm in embryonic and adult hearts. Moreover, both TMEM43 variants displayed cardiac morphological defects at juvenile stages and ultrastructural changes within the myocardium, accompanied by dysregulated gene expression profiles in adulthood. Finally, CRISPR/Cas9 mutants demonstrated an age-dependent cardiac phenotype characterized by heart enlargement in adulthood. In conclusion, our findings suggest ultrastructural remodeling and transcriptomic alterations underlying the development of structural and functional cardiac defects in TMEM43-associated cardiomyopathy. KW - TMEM43 KW - arrhythmogenic cardiomyopathy KW - zebrafish KW - CRISPR/Cas9 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286025 SN - 1422-0067 VL - 23 IS - 17 ER - TY - JOUR A1 - Gmach, Philipp A1 - Bathe-Peters, Marc A1 - Telugu, Narasimha A1 - Miller, Duncan C. A1 - Annibale, Paolo T1 - Fluorescence spectroscopy of low-level endogenous β-adrenergic receptor expression at the plasma membrane of differentiating human iPSC-derived cardiomyocytes JF - International Journal of Molecular Sciences N2 - The potential of human-induced pluripotent stem cells (hiPSCs) to be differentiated into cardiomyocytes (CMs) mimicking adult CMs functional morphology, marker genes and signaling characteristics has been investigated since over a decade. The evolution of the membrane localization of CM-specific G protein-coupled receptors throughout differentiation has received, however, only limited attention to date. We employ here advanced fluorescent spectroscopy, namely linescan Fluorescence Correlation Spectroscopy (FCS), to observe how the plasma membrane abundance of the β\(_1\)- and β\(_2\)-adrenergic receptors (β\(_{1/2}\)-ARs), labelled using a bright and photostable fluorescent antagonist, evolves during the long-term monolayer culture of hiPSC-derived CMs. We compare it to the kinetics of observed mRNA levels in wildtype (WT) hiPSCs and in two CRISPR/Cas9 knock-in clones. We conduct these observations against the backdrop of our recent report of cell-to-cell expression variability, as well as of the subcellular localization heterogeneity of β-ARs in adult CMs. KW - GPCR KW - β-adrenergic receptors KW - hiPSC-CM KW - cardiomyocyte KW - fluorescence correlation spectroscopy KW - FCS KW - fluorescence KW - CRISPR/Cas9 KW - differentiation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-288277 SN - 1422-0067 VL - 23 IS - 18 ER - TY - JOUR A1 - Engstler, Markus A1 - Beneke, Tom T1 - Gene editing and scalable functional genomic screening in Leishmania species using the CRISPR/Cas9 cytosine base editor toolbox LeishBASEedit JF - eLife N2 - CRISPR/Cas9 gene editing has revolutionised loss-of-function experiments in Leishmania, the causative agent of leishmaniasis. As Leishmania lack a functional non-homologous DNA end joining pathway however, obtaining null mutants typically requires additional donor DNA, selection of drug resistance-associated edits or time-consuming isolation of clones. Genome-wide loss-of-function screens across different conditions and across multiple Leishmania species are therefore unfeasible at present. Here, we report a CRISPR/Cas9 cytosine base editor (CBE) toolbox that overcomes these limitations. We employed CBEs in Leishmania to introduce STOP codons by converting cytosine into thymine and created http://www.leishbaseedit.net/ for CBE primer design in kinetoplastids. Through reporter assays and by targeting single- and multi-copy genes in L. mexicana, L. major, L. donovani, and L. infantum, we demonstrate how this tool can efficiently generate functional null mutants by expressing just one single-guide RNA, reaching up to 100% editing rate in non-clonal populations. We then generated a Leishmania-optimised CBE and successfully targeted an essential gene in a plasmid library delivered loss-of-function screen in L. mexicana. Since our method does not require DNA double-strand breaks, homologous recombination, donor DNA, or isolation of clones, we believe that this enables for the first time functional genetic screens in Leishmania via delivery of plasmid libraries. KW - CRISPR/Cas9 KW - Leishmania KW - cytosine base editor (CBE) toolbox KW - gene editing KW - scalable functional genomic screening KW - LeishBASEedit Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-350002 VL - 12 ER -