@article{AgranovskyDolyaGorboulevetal.1981, author = {Agranovsky, A. A. and Dolya, V. V. and Gorboulev, Valentin G. and Kozlov, J. V. and Atabekov, J. G.}, title = {Aminoacylation of barley stripe mosaic virus RNA: polyadenylate-containing RNA has a 3'-terminal tyrosine-accepting structure}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32566}, year = {1981}, abstract = {Barley stripe mosaic virus (BSMV) RNA which was previously reported to contain poly(A) sequences (Agranovsky et al., 1978) can be specifically esterified with tyrosine in vitro in the presence of an aminoacyl-tRNA synthetase fraction from wheat embryos. All the three RNA components of the BSMV strain with a three-component genome (Norwich) and both RNA components of a two-component strain (Russian) can be tyrosylated. The poly(A)-containing (bound to oligo(dT)-cellulose) and poly(A)-deficient(not bound to oligo(dT)-cellulose) fractions of BSMV RNA display a similar amino acidaccepting ability. The nucleotide sequence which accepts tyrosine is coupled with the intact genomic polyadenylated BSMV RNA. The viral RNA isolated after sucrose density gradient centrifugation under drastic denaturing conditions retains its aminoacylating activity, which suggests that this activity is not due to the presence in a BSMV RNA preparation of a tyrosine tRNA associated with BSMV RNA. Inhibition of aminoacylation of the 3'-oxidized (treated with sodium metaperiodate) BSMV RNA suggests that the tyrosine-accepting structure is localized at the 3' terminus of BSMV RNA molecules. It is shown that segments of different lengths obtained upon random fragmentation can be tyrosylated. The 3'-terminal (tyrosine-accepting) poly(A)+ segments can be isolated. The shortest segments of viral RNA capable of being aminoacylated [i.e., containing both tRNA-like structure and poly(A)] consists of approximately 150-200 nucleotides. The analysis of the oligonucleotides derived from individual BSMV RNA components labeled with 32P at the 3' end revealed two types of 3'-terminal sequences different from poly(A). It is suggested that a poly(A) sequence is intercalated between a 3'-terminal tyrosineaccepting structure and the 5'-terminal portion of poly(A)+ BSMV RNA.}, language = {en} } @article{AktasUpcinHenkeetal.2019, author = {Aktas, Bertal H. and Upcin, Berin and Henke, Erik and Padmasekar, Manju and Qin, Xuebin and Erg{\"u}n, S{\"u}leyman}, title = {The Best for the Most Important: Maintaining a Pristine Proteome in Stem and Progenitor Cells}, series = {Stem Cells International}, journal = {Stem Cells International}, doi = {10.1155/2019/1608787}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227769}, pages = {1-20}, year = {2019}, abstract = {Pluripotent stem cells give rise to reproductively enabled offsprings by generating progressively lineage-restricted multipotent stem cells that would differentiate into lineage-committed stem and progenitor cells. These lineage-committed stem and progenitor cells give rise to all adult tissues and organs. Adult stem and progenitor cells are generated as part of the developmental program and play critical roles in tissue and organ maintenance and/or regeneration. The ability of pluripotent stem cells to self-renew, maintain pluripotency, and differentiate into a multicellular organism is highly dependent on sensing and integrating extracellular and extraorganismal cues. Proteins perform and integrate almost all cellular functions including signal transduction, regulation of gene expression, metabolism, and cell division and death. Therefore, maintenance of an appropriate mix of correctly folded proteins, a pristine proteome, is essential for proper stem cell function. The stem cells' proteome must be pristine because unfolded, misfolded, or otherwise damaged proteins would interfere with unlimited self-renewal, maintenance of pluripotency, differentiation into downstream lineages, and consequently with the development of properly functioning tissue and organs. Understanding how various stem cells generate and maintain a pristine proteome is therefore essential for exploiting their potential in regenerative medicine and possibly for the discovery of novel approaches for maintaining, propagating, and differentiating pluripotent, multipotent, and adult stem cells as well as induced pluripotent stem cells. In this review, we will summarize cellular networks used by various stem cells for generation and maintenance of a pristine proteome. We will also explore the coordination of these networks with one another and their integration with the gene regulatory and signaling networks.}, language = {en} } @article{AppeltMenzelCubukovaGuentheretal.2017, author = {Appelt-Menzel, Antje and Cubukova, Alevtina and G{\"u}nther, Katharina and Edenhofer, Frank and Piontek, J{\"o}rg and Krause, Gerd and St{\"u}ber, Tanja and Walles, Heike and Neuhaus, Winfried and Metzger, Marco}, title = {Establishment of a Human Blood-Brain Barrier Co-culture Model Mimicking the Neurovascular Unit Using Induced Pluri- and Multipotent Stem Cells}, series = {Stem Cell Reports}, volume = {8}, journal = {Stem Cell Reports}, number = {4}, doi = {10.1016/j.stemcr.2017.02.021}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170982}, pages = {894-906}, year = {2017}, abstract = {In vitro models of the human blood-brain barrier (BBB) are highly desirable for drug development. This study aims to analyze a set of ten different BBB culture models based on primary cells, human induced pluripotent stem cells (hiPSCs), and multipotent fetal neural stem cells (fNSCs). We systematically investigated the impact of astrocytes, pericytes, and NSCs on hiPSC-derived BBB endothelial cell function and gene expression. The quadruple culture models, based on these four cell types, achieved BBB characteristics including transendothelial electrical resistance (TEER) up to 2,500 Ω cm\(^{2}\) and distinct upregulation of typical BBB genes. A complex in vivo-like tight junction (TJ) network was detected by freeze-fracture and transmission electron microscopy. Treatment with claudin-specific TJ modulators caused TEER decrease, confirming the relevant role of claudin subtypes for paracellular tightness. Drug permeability tests with reference substances were performed and confirmed the suitability of the models for drug transport studies.}, language = {en} } @article{ArndtHoffackerZellmeretal.2014, author = {Arndt, Andreas and Hoffacker, Peter and Zellmer, Konstantin and Goecer, Oktay and Recks, Mascha S. and Kuerten, Stefanie}, title = {Conventional Housing Conditions Attenuate the Development of Experimental Autoimmune Encephalomyelitis}, series = {PLoS ONE}, volume = {9}, journal = {PLoS ONE}, number = {6}, doi = {10.1371/journal.pone.0099794}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119603}, pages = {e99794}, year = {2014}, abstract = {BACKGROUND: The etiology of multiple sclerosis (MS) has remained unclear, but a causative contribution of factors outside the central nervous system (CNS) is conceivable. It was recently suggested that gut bacteria trigger the activation of CNS-reactive T cells and the development of demyelinative disease. METHODS: C57BL/6 (B6) mice were kept either under specific pathogen free or conventional housing conditions, immunized with the myelin basic protein (MBP)-proteolipid protein (PLP) fusion protein MP4 and the development of EAE was clinically monitored. The germinal center size of the Peyer's patches was determined by immunohistochemistry in addition to the level of total IgG secretion which was assessed by ELISPOT. ELISPOT assays were also used to measure MP4-specific T cell and B cell responses in the Peyer's patches and the spleen. Ear swelling assays were performed to determine the extent of delayed-type hypersensitivity reactions in specific pathogen free and conventionally housed mice. RESULTS: In B6 mice that were actively immunized with MP4 and kept under conventional housing conditions clinical disease was significantly attenuated compared to specific pathogen free mice. Conventionally housed mice displayed increased levels of IgG secretion in the Peyer's patches, while the germinal center formation in the gut and the MP4-specific TH17 response in the spleen were diminished after immunization. Accordingly, these mice displayed an attenuated delayed type hypersensitivity (DTH) reaction in ear swelling assays. CONCLUSIONS: The data corroborate the notion that housing conditions play a substantial role in the induction of murine EAE and suggest that the presence of gut bacteria might be associated with a decreased immune response to antigens of lower affinity. This concept could be of importance for MS and calls for caution when considering the therapeutic approach to treat patients with antibiotics."}, language = {en} } @article{ArtyukovaGorboulevRodionovaetal.1985, author = {Artyukova, E. V. and Gorboulev, Valentin G. and Rodionova, N. P. and Krylov, A. V. and Atabekov, J. G.}, title = {Comparative study of structural peculiarities and translation of potexvirus RNAs}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-46985}, year = {1985}, abstract = {Structural peculiarities of the S'-end segments of genomic RNA were studied in F potato virus (F-PV) and white clover mosaic virus (WCMV). The methods of affinity chromatography on oligo(dT) cellulose and oligonucleotide mapping revealed a prolonged (up to 210 nucleotides) polyadenyl sequence at the 3'-end of F-PV RNA. A polyadenyl sequence is missing at the 3'end of WCMV RNA. A study of the translation products of WCMV and F-PV RNAs in a oe11-free protein-synthesizing system derived from rabbit reticulocytes showed that polypeptides electrophoretically comigrating with a structural protein of either virus were synthesized alongside high-molecular-weight polypeptides (M\(_r\)\(\approx\) 180-150 kdaltons).}, language = {en} } @article{AscheidBaumannFunkeetal.2023, author = {Ascheid, David and Baumann, Magdalena and Funke, Caroline and Volz, Julia and Pinnecker, J{\"u}rgen and Friedrich, Mike and H{\"o}hn, Marie and Nandigama, Rajender and Erg{\"u}n, S{\"u}leyman and Nieswandt, Bernhard and Heinze, Katrin G. and Henke, Erik}, title = {Image-based modeling of vascular organization to evaluate anti-angiogenic therapy}, series = {Biology Direct}, volume = {18}, journal = {Biology Direct}, doi = {10.1186/s13062-023-00365-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357242}, year = {2023}, abstract = {In tumor therapy anti-angiogenic approaches have the potential to increase the efficacy of a wide variety of subsequently or co-administered agents, possibly by improving or normalizing the defective tumor vasculature. Successful implementation of the concept of vascular normalization under anti-angiogenic therapy, however, mandates a detailed understanding of key characteristics and a respective scoring metric that defines an improved vasculature and thus a successful attempt. Here, we show that beyond commonly used parameters such as vessel patency and maturation, anti-angiogenic approaches largely benefit if the complex vascular network with its vessel interconnections is both qualitatively and quantitatively assessed. To gain such deeper insight the organization of vascular networks, we introduce a multi-parametric evaluation of high-resolution angiographic images based on light-sheet fluorescence microscopy images of tumors. We first could pinpoint key correlations between vessel length, straightness and diameter to describe the regular, functional and organized structure observed under physiological conditions. We found that vascular networks from experimental tumors diverted from those in healthy organs, demonstrating the dysfunctionality of the tumor vasculature not only on the level of the individual vessel but also in terms of inadequate organization into larger structures. These parameters proofed effective in scoring the degree of disorganization in different tumor entities, and more importantly in grading a potential reversal under treatment with therapeutic agents. The presented vascular network analysis will support vascular normalization assessment and future optimization of anti-angiogenic therapy.}, language = {en} } @article{BailNotzRovitusoetal.2017, author = {Bail, Kathrin and Notz, Quirin and Rovituso, Damiano M. and Schampel, Andrea and Wunsch, Marie and Koeniger, Tobias and Schropp, Verena and Bharti, Richa and Scholz, Claus-Juergen and Foerstner, Konrad U. and Kleinschnitz, Christoph and Kuerten, Stefanie}, title = {Differential effects of FTY720 on the B cell compartment in a mouse model of multiple sclerosis.}, series = {Journal of Neuroinflammation}, volume = {14}, journal = {Journal of Neuroinflammation}, number = {148}, doi = {10.1186/s12974-017-0924-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157869}, year = {2017}, abstract = {Background: MP4-induced experimental autoimmune encephalomyelitis (EAE) is a mouse model of multiple sclerosis (MS), which enables targeted research on B cells, currently much discussed protagonists in MS pathogenesis. Here, we used this model to study the impact of the S1P1 receptor modulator FTY720 (fingolimod) on the autoreactive B cell and antibody response both in the periphery and the central nervous system (CNS). Methods: MP4-immunized mice were treated orally with FTY720 for 30 days at the peak of disease or 50 days after EAE onset. The subsequent disease course was monitored and the MP4-specific B cell/antibody response was measured by ELISPOT and ELISA. RNA sequencing was performed to determine any effects on B cell-relevant gene expression. S1P\(_{1}\) receptor expression by peripheral T and B cells, B cell subset distribution in the spleen and B cell infiltration into the CNS were studied by flow cytometry. The formation of B cell aggregates and of tertiary lymphoid organs (TLOs) was evaluated by histology and immunohistochemistry. Potential direct effects of FTY720 on B cell aggregation were studied in vitro. Results: FTY720 significantly attenuated clinical EAE when treatment was initiated at the peak of EAE. While there was a significant reduction in the number of T cells in the blood after FTY720 treatment, B cells were only slightly diminished. Yet, there was evidence for the modulation of B cell receptor-mediated signaling upon FTY720 treatment. In addition, we detected a significant increase in the percentage of B220\(^{+}\) B cells in the spleen both in acute and chronic EAE. Whereas acute treatment completely abrogated B cell aggregate formation in the CNS, the numbers of infiltrating B cells and plasma cells were comparable between vehicle- and FTY720-treated mice. In addition, there was no effect on already developed aggregates in chronic EAE. In vitro B cell aggregation assays suggested the absence of a direct effect of FTY720 on B cell aggregation. However, FTY720 impacted the evolution of B cell aggregates into TLOs. Conclusions: The data suggest differential effects of FTY720 on the B cell compartment in MP4-induced EAE.}, language = {en} } @article{BeheraJainGangulietal.2022, author = {Behera, Ananyaashree and Jain, Preeti and Ganguli, Geetanjali and Biswas, Mainak and Padhi, Avinash and Pattanaik, Kali Prasad and Nayak, Barsa and Erg{\"u}n, S{\"u}leyman and Hagens, Kristine and Redinger, Natalja and Saqib, Mohd and Mishra, Bibhuti B. and Schaible, Ulrich E. and Karnati, Srikanth and Sonawane, Avinash}, title = {Mycobacterium tuberculosis acetyltransferase suppresses oxidative stress by inducing peroxisome formation in macrophages}, series = {International Journal of Molecular Sciences}, volume = {23}, journal = {International Journal of Molecular Sciences}, number = {5}, issn = {1422-0067}, doi = {10.3390/ijms23052584}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284080}, year = {2022}, abstract = {Mycobacterium tuberculosis (Mtb) inhibits host oxidative stress responses facilitating its survival in macrophages; however, the underlying molecular mechanisms are poorly understood. Here, we identified a Mtb acetyltransferase (Rv3034c) as a novel counter actor of macrophage oxidative stress responses by inducing peroxisome formation. An inducible Rv3034c deletion mutant of Mtb failed to induce peroxisome biogenesis, expression of the peroxisomal β-oxidation pathway intermediates (ACOX1, ACAA1, MFP2) in macrophages, resulting in reduced intracellular survival compared to the parental strain. This reduced virulence phenotype was rescued by repletion of Rv3034c. Peroxisome induction depended on the interaction between Rv3034c and the macrophage mannose receptor (MR). Interaction between Rv3034c and MR induced expression of the peroxisomal biogenesis proteins PEX5p, PEX13p, PEX14p, PEX11β, PEX19p, the peroxisomal membrane lipid transporter ABCD3, and catalase. Expression of PEX14p and ABCD3 was also enhanced in lungs from Mtb aerosol-infected mice. This is the first report that peroxisome-mediated control of ROS balance is essential for innate immune responses to Mtb but can be counteracted by the mycobacterial acetyltransferase Rv3034c. Thus, peroxisomes represent interesting targets for host-directed therapeutics to tuberculosis.}, language = {en} } @article{BielmeierRothSchmittetal.2021, author = {Bielmeier, Christina B. and Roth, Saskia and Schmitt, Sabrina I. and Boneva, Stefaniya K. and Schlecht, Anja and Vallon, Mario and Tamm, Ernst R. and Erg{\"u}n, S{\"u}leyman and Neueder, Andreas and Braunger, Barbara M.}, title = {Transcriptional profiling identifies upregulation of neuroprotective pathways in retinitis pigmentosa}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {12}, issn = {1422-0067}, doi = {10.3390/ijms22126307}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260769}, year = {2021}, abstract = {Hereditary retinal degenerations like retinitis pigmentosa (RP) are among the leading causes of blindness in younger patients. To enable in vivo investigation of cellular and molecular mechanisms responsible for photoreceptor cell death and to allow testing of therapeutic strategies that could prevent retinal degeneration, animal models have been created. In this study, we deeply characterized the transcriptional profile of mice carrying the transgene rhodopsin V20G/P23H/P27L (VPP), which is a model for autosomal dominant RP. We examined the degree of photoreceptor degeneration and studied the impact of the VPP transgene-induced retinal degeneration on the transcriptome level of the retina using next generation RNA sequencing (RNASeq) analyses followed by weighted correlation network analysis (WGCNA). We furthermore identified cellular subpopulations responsible for some of the observed dysregulations using in situ hybridizations, immunofluorescence staining, and 3D reconstruction. Using RNASeq analysis, we identified 9256 dysregulated genes and six significantly associated gene modules in the subsequently performed WGCNA. Gene ontology enrichment showed, among others, dysregulation of genes involved in TGF-β regulated extracellular matrix organization, the (ocular) immune system/response, and cellular homeostasis. Moreover, heatmaps confirmed clustering of significantly dysregulated genes coding for components of the TGF-β, G-protein activated, and VEGF signaling pathway. 3D reconstructions of immunostained/in situ hybridized sections revealed retinal neurons and M{\"u}ller cells as the major cellular population expressing representative components of these signaling pathways. The predominant effect of VPP-induced photoreceptor degeneration pointed towards induction of neuroinflammation and the upregulation of neuroprotective pathways like TGF-β, G-protein activated, and VEGF signaling. Thus, modulation of these processes and signaling pathways might represent new therapeutic options to delay the degeneration of photoreceptors in diseases like RP.}, language = {en} } @article{BielmeierSchmittKleefeldtetal.2022, author = {Bielmeier, Christina B. and Schmitt, Sabrina I. and Kleefeldt, Nikolai and Boneva, Stefaniya K. and Schlecht, Anja and Vallon, Mario and Tamm, Ernst R. and Hillenkamp, Jost and Erg{\"u}n, S{\"u}leyman and Neueder, Andreas and Braunger, Barbara M.}, title = {Deficiency in retinal TGFβ signaling aggravates neurodegeneration by modulating pro-apoptotic and MAP kinase pathways}, series = {International Journal of Molecular Sciences}, volume = {23}, journal = {International Journal of Molecular Sciences}, number = {5}, issn = {1422-0067}, doi = {10.3390/ijms23052626}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-283971}, year = {2022}, abstract = {Transforming growth factor β (TGFβ) signaling has manifold functions such as regulation of cell growth, differentiation, migration, and apoptosis. Moreover, there is increasing evidence that it also acts in a neuroprotective manner. We recently showed that TGFβ receptor type 2 (Tgfbr2) is upregulated in retinal neurons and M{\"u}ller cells during retinal degeneration. In this study we investigated if this upregulation of TGFβ signaling would have functional consequences in protecting retinal neurons. To this end, we analyzed the impact of TGFβ signaling on photoreceptor viability using mice with cell type-specific deletion of Tgfbr2 in retinal neurons and M{\"u}ller cells (Tgfbr2\(_{ΔOC}\)) in combination with a genetic model of photoreceptor degeneration (VPP). We examined retinal morphology and the degree of photoreceptor degeneration, as well as alterations of the retinal transcriptome. In summary, retinal morphology was not altered due to TGFβ signaling deficiency. In contrast, VPP-induced photoreceptor degeneration was drastically exacerbated in double mutant mice (Tgfbr2\(_{ΔOC}\); VPP) by induction of pro-apoptotic genes and dysregulation of the MAP kinase pathway. Therefore, TGFβ signaling in retinal neurons and M{\"u}ller cells exhibits a neuroprotective effect and might pose promising therapeutic options to attenuate photoreceptor degeneration in humans.}, language = {en} }