Transcriptional signatures of Itk-deficient CD3+, CD4+ and CD8+ T-cells

<p>Abstract</p> <p>Background</p> <p>The Tec-family kinase Itk plays an important role during T-cell activation and function, and controls also conventional versus innate-like T-cell development. We have characterized the transcriptome of Itk-deficient CD3⁺T-cells, including CD4⁺and CD8⁺subsets, using Affymetrix microarrays.</p> <p>Results</p> <p>The largest difference between Itk^-/-and Wt CD3⁺T-cells was found in unstimulated cells, e.g. for killer cell lectin-like receptors. Compared to anti-CD3-stimulation, anti-CD3/CD28 significantly decreased the number of transcripts suggesting that the CD28 co-stimulatory pathway is mainly independent of Itk. The signatures of CD4⁺and CD8⁺T-cell subsets identified a greater differential expression than in total CD3⁺cells. Cyclosporin A (CsA)-treatment had a stronger effect on transcriptional regulation than Itk-deficiency, suggesting that only a fraction of TCR-mediated calcineurin/NFAT-activation is dependent on Itk. Bioinformatic analysis of NFAT-sites of the group of transcripts similarly regulated by Itk-deficiency and CsA-treatment, followed by chromatin-immunoprecipitation, revealed NFATc1-binding to the <it>Bub1</it>, <it>IL7R, Ctla2a</it>, <it>Ctla2b</it>, and <it>Schlafen1 </it>genes. Finally, to identify transcripts that are regulated by Tec-family kinases in general, we compared the expression profile of Itk-deficient T-cells with that of Btk-deficient B-cells and a common set of transcripts was found.</p> <p>Conclusion</p> <p>Taken together, our study provides a general overview about the global transcriptional changes in the absence of Itk.</p

Novel endosomolytic compounds enable highly potent delivery of antisense oligonucleotides

The therapeutic and research potentials of oligonucleotides (ONs) have been hampered in part by their inability to effectively escape endosomal compartments to reach their cytosolic and nuclear targets. Splice-switching ONs (SSOs) can be used with endosomolytic small molecule compounds to increase functional delivery. So far, development of these compounds has been hindered by a lack of high-resolution methods that can correlate SSO trafficking with SSO activity. Here we present in-depth characterization of two novel endosomolytic compounds by using a combination of microscopic and functional assays with high spatiotemporal resolution. This system allows the visualization of SSO trafficking, evaluation of endosomal membrane rupture, and quantitates SSO functional activity on a protein level in the presence of endosomolytic compounds. We confirm that the leakage of SSO into the cytosol occurs in parallel with the physical engorgement of LAMP1-positive late endosomes and lysosomes. We conclude that the new compounds interfere with SSO trafficking to the LAMP1-positive endosomal compartments while inducing endosomal membrane rupture and concurrent ON escape into the cytosol. The efficacy of these compounds advocates their use as novel, potent, and quick-acting transfection reagents for antisense ONs

ANKRD54 preferentially selects Bruton's Tyrosine Kinase (BTK) from a Human Src-Homology 3 (SH3) domain library

Bruton's Tyrosine Kinase (BTK) is a cytoplasmic protein tyrosine kinase with a fundamental role in B-lymphocyte development and activation. The nucleocytoplasmic shuttling of BTK is specifically modulated by the Ankyrin Repeat Domain 54 (ANKRD54) protein and the interaction is known to be exclusively SH3-dependent. To identify the spectrum of the ANKRD54 SH3-interactome, we applied phage-display screening of a library containing all the 296 human SH3 domains. The BTK-SH3 domain was the prime interactor. Quantitative western blotting analysis demonstrated the accuracy of the screening procedure. Revealing the spectrum and specificity of ANKRD54-interactome is a critical step toward functional analysis in cells and tissues.Peer reviewe

Specific dsDNA recognition by a mimic of the DNA binding domain of the c-Myc/Max transcription factor

We here report on the synthesis of the first mimic of the DNA binding domain of the c-Myc/Max-bHLH-ZIP transcription factor able to selectively recognize its cognate E-box sequence 50'-CACGTG-3' through the major groove of the double-stranded DNA. The designed peptidosteroid conjugate was shown to be effective as DNA binder in the presence of excess competitor DNA

Cyclodextrin-peptide conjugates for sequence specific DNA binding

Synthetic models of bZIP transcription factors have been developed with the capability of specific DNA recognition. Our design is based on the CuAAC mediated conjugation of basic region Leucine Zipper peptides to different derivatives of alpha,beta and gamma-cyclodextrins equipped with azide functionalities. Thorough optimization of reaction conditions allowed convergent and simultaneous conjugation of two long unprotected cationic peptides to cyclodextrin-bis azide derivatives. The resulting constructs were shown to specifically recognize their cognate DNA sequence with nM affinities. In comparison with previously developed TF models, the derivatives described here combine the enhanced DNA binding capabilities with an easy and convergent synthetic route

Expression Analysis in Multiple Muscle Groups and Serum Reveals Complexity in the MicroRNA Transcriptome of the mdx Mouse with Implications for Therapy

MicroRNAs (miRNAs) are a class of small RNAs that regulate gene expression and are implicated in wide-ranging cellular processes and pathological conditions including Duchenne muscular dystrophy (DMD). We have compared differential miRNA expression in proximal and distal limb muscles, diaphragm, heart and serum in the mdx mouse relative to wild-type controls. Global transcriptome analysis revealed muscle-specific patterns of differential miRNA expression as well as a number of changes common between tissues, including previously identified dystromirs. In the case of miR-31 and miR-34c, upregulation of primary-miRNA transcripts, precursor hairpins and all mature miRNAs derived from the same transcript or miRNA cluster, strongly suggests transcriptional regulation of these miRNAs. The most striking differences in differential miRNA expression were between muscle tissue and serum. Specifically, miR-1, miR-133a, and miR-206 were highly abundant in mdx serum but downregulated or modestly upregulated in muscle, suggesting that these miRNAs are promising disease biomarkers. Indeed, the relative serum levels of these miRNAs were normalized in response to peptide-phosphorodiamidate morpholino oligonucleotide (PMO) mediated dystrophin restoration therapy. This study has revealed further complexity in the miRNA transcriptome of the mdx mouse, an understanding of which will be valuable in the development of novel therapeutics and for monitoring their efficacy

Micro-minicircle Gene Therapy: Implications of Size on Fermentation, Complexation, Shearing Resistance, and Expression

The minicircle (MC), composed of eukaryotic sequences only, is an interesting approach to increase the safety and efficiency of plasmid-based vectors for gene therapy. In this paper, we investigate micro-MC (miMC) vectors encoding small regulatory RNA. We use a construct encoding a splice-correcting U7 small nuclear RNA, which results in a vector of 650 base pairs (bp), as compared to a conventional 3600 bp plasmid carrying the same expression cassette. Furthermore, we construct miMCs of varying sizes carrying different number of these cassettes. This allows us to evaluate how size influences production, super-coiling, stability and efficiency of the vector. We characterize coiling morphology by atomic force microscopy and measure the resistance to shearing forces caused by an injector device, the Biojector. We compare the behavior of miMCs and plasmids in vitro using lipofection and electroporation, as well as in vivo in mice. We here show that when the size of the miMC is reduced, the formation of dimers and trimers increases. There seems to be a lower size limit for efficient expression. We demonstrate that miMCs are more robust than plasmids when exposed to shearing forces, and that they show extended expression in vivo

Correlating In Vitro Splice Switching Activity With Systemic In Vivo Delivery Using Novel ZEN-modified Oligonucleotides

Splice switching oligonucleotides (SSOs) induce alternative splicing of pre-mRNA and typically employ chemical modifications to increase nuclease resistance and binding affinity to target pre-mRNA. Here we describe a new SSO non-base modifier (a naphthyl-azo group, “ZEN™”) to direct exon exclusion in mutant dystrophin pre-mRNA to generate functional dystrophin protein. The ZEN modifier is placed near the ends of a 2′-O-methyl (2′OMe) oligonucleotide, increasing melting temperature and potency over unmodified 2′OMe oligonucleotides. In cultured H2K cells, a ZEN-modified 2′OMe phosphorothioate (PS) oligonucleotide delivered by lipid transfection greatly enhanced dystrophin exon skipping over the same 2′OMePS SSO lacking ZEN. However, when tested using free gymnotic uptake in vitro and following systemic delivery in vivo in dystrophin deficient mdx mice, the same ZEN-modified SSO failed to enhance potency. Importantly, we show for the first time that in vivo activity of anionic SSOs is modelled in vitro only when using gymnotic delivery. ZEN is thus a novel modifier that enhances activity of SSOs in vitro but will require improved delivery methods before its in vivo clinical potential can be realized