المؤلفون: Mona E. Arnold, Larissa Schoeneburg, Markus Lamla, Alexander J. C. Kuehne

المصدر: Molecules, Vol 29, Iss 5, p 995 (2024)

مصطلحات موضوعية: triaryl methyl radicals, light-emitting radicals, cell culture, charge transfer states, photoluminescence quantum yield, Organic chemistry, QD241-441

الوصف: Stable tris(trichlorophenyl)methyl radicals have gained interest as all-organic bioimaging agents combining fluorescent and paramagnetic properties. However, cellular uptake has so far only been reported for nanoparticles, because molecular hydrophobic trityl radicals are not soluble in aqueous media. Here, we report the synthesis and characterization of new water-soluble tris(trichlorophenyl)methyl radical derivatives exhibiting red doublet emission. Solubility in water is achieved through functionalization with oligoethylene glycol (OEG) chains. The emission behavior of OEG functionalized trityl radicals is studied in polar environments. Donor-functionalization with carbazole evokes a charge-transfer excited state that is efficiently quenched in polar solvents. In contrast, click-reaction mediated attachment of OEG-azide and trityl acetylene furnishes a triazole functionalized radical with locally excited states and emission in water. Confocal fluorescence microscopy proves successful uptake of the material by macrophages in cell culture, showing the potential of our water soluble trityl radical for fluorescence bioimaging.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/1420-3049/29/5/995Test; https://doaj.org/toc/1420-3049Test

الوصول الحر: https://doaj.org/article/4dc53c5c12e14e7283f92ce1ee01f326Test

المؤلفون: Onofrio Zirafi, Kyeong-Ae Kim, Ludger Ständker, Katharina B. Mohr, Daniel Sauter, Anke Heigele, Silvia F. Kluge, Eliza Wiercinska, Doreen Chudziak, Rudolf Richter, Barbara Moepps, Peter Gierschik, Virag Vas, Hartmut Geiger, Markus Lamla, Tanja Weil, Timo Burster, Andreas Zgraja, Francois Daubeuf, Nelly Frossard, Muriel Hachet-Haas, Fabian Heunisch, Christoph Reichetzeder, Jean-Luc Galzi, Javier Pérez-Castells, Angeles Canales-Mayordomo, Jesus Jiménez-Barbero, Guillermo Giménez-Gallego, Marion Schneider, James Shorter, Amalio Telenti, Berthold Hocher, Wolf-Georg Forssmann, Halvard Bonig, Frank Kirchhoff, Jan Münch

المصدر: Cell Reports, Vol 11, Iss 5, Pp 737-747 (2015)

مصطلحات موضوعية: Biology (General), QH301-705.5

الوصف: CXCL12-CXCR4 signaling controls multiple physiological processes and its dysregulation is associated with cancers and inflammatory diseases. To discover as-yet-unknown endogenous ligands of CXCR4, we screened a blood-derived peptide library for inhibitors of CXCR4-tropic HIV-1 strains. This approach identified a 16 amino acid fragment of serum albumin as an effective and highly specific CXCR4 antagonist. The endogenous peptide, termed EPI-X4, is evolutionarily conserved and generated from the highly abundant albumin precursor by pH-regulated proteases. EPI-X4 forms an unusual lasso-like structure and antagonizes CXCL12-induced tumor cell migration, mobilizes stem cells, and suppresses inflammatory responses in mice. Furthermore, the peptide is abundant in the urine of patients with inflammatory kidney diseases and may serve as a biomarker. Our results identify EPI-X4 as a key regulator of CXCR4 signaling and introduce proteolysis of an abundant precursor protein as an alternative concept for chemokine receptor regulation.

وصف الملف: electronic resource

العلاقة: http://www.sciencedirect.com/science/article/pii/S2211124715003526Test; https://doaj.org/toc/2211-1247Test

الوصول الحر: https://doaj.org/article/6f4fd359e6c246c58166a8fdf0934801Test

المؤلفون: Markus Lamla, Josef Högel, Dieter Kaufmann, Ralf Kemkemer, Kevin Mellert, Michael Uhl

المصدر: Genes, Vol 2, Iss 3, Pp 562-577 (2011)

مصطلحات موضوعية: splicing, noise, splice errors, mRNA processing, Genetics, QH426-470

الوصف: In human pre-mRNA splicing, infrequent errors occur resulting in erroneous splice products as shown in a genome-wide approach. One characteristic subgroup consists of products lacking one cassette exon. The noise in the splicing process, represented by those misspliced products, can be increased by cold shock treatment or by inhibiting the nonsense mediated decay. Here, we investigated whether the splicing noise frequency increases with age in vivo in peripheral bloods cells or in vitro in cultured and aged fibroblasts from healthy donors. Splicing noise frequency was measured for four erroneously skipped NF1 exons and one exon of RABAC1, AATF and PCGF2 by RT-qPCR. Measurements were validated in cultured fibroblasts treated with cold shock or puromycin. Intragenic but not interpersonal differences were detected in splicing noise frequencies in vivo in peripheral blood cells of 11 healthy donors (15 y–85 y) and in in vitro senescent fibroblasts from three further donors. No correlation to the age of the donors was found in the splicing noise frequencies. Our data demonstrates that splicing error frequencies are not altered by age in peripheral blood cells or in vitro aged fibroblasts in the tested exons of the four investigated genes, indicating a high importance of correct splicing in these proliferating aged cells.

وصف الملف: electronic resource

العلاقة: http://www.mdpi.com/2073-4425/2/3/562Test/; https://doaj.org/toc/2073-4425Test

الوصول الحر: https://doaj.org/article/768097d6b00c4bff8493cac65296d90dTest

المؤلفون: Kevin Mellert, Markus Lamla, Klaus Scheffzek, Rainer Wittig, Dieter Kaufmann

المصدر: PLoS ONE, Vol 7, Iss 12, p e52473 (2012)

مصطلحات موضوعية: Medicine, Science

الوصف: Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin) into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI) treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP) mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro.

وصف الملف: electronic resource

العلاقة: http://europepmc.org/articles/PMC3528648?pdf=renderTest; https://doaj.org/toc/1932-6203Test

الوصول الحر: https://doaj.org/article/132d8778fc81408ea408ce1c6ca2be3dTest