Project description:The mechanical properties of solid tumors influence tumor cell phenotype and ability to invade into surrounding tissues. Using bioengineered scaffolds to provide a matrix microenvironment for patient-derived glioblastoma (GBM) spheroids, this study demonstrates that a soft, brain-like matrix induces GBM cells to shift to a glycolysis-weighted metabolic state which supports invasive behavior. We first show that orthotopic murine GBM tumors are stiffer than peri-tumoral brain tissues, but tumor stiffness is heterogenous where tumor edges are softer than the tumor core. Then, we developed three-dimensional scaffolds with µ-compressive moduli resembling either stiffer, tumor core or softer, peri-tumoral brain tissue. We demonstrate that the softer matrix microenvironment induces a shift in GBM cell metabolism toward glycolysis which manifests in lower proliferation rate and increased migration activities. Finally, we show that these mechanical cues are transduced from the matrix via CD44 and integrin receptors to induce metabolic and phenotypic changes in cancer cells.
Project description:Spliceosomal snRNA are key components of small nuclear ribonucleoprotein particles (snRNPs), the building blocks of the spliceosome. The biogenesis of snRNPs is a complex process involving multiple cellular and subcellular compartments, the details of which are yet to be described. In short, the snRNA is exported to the cytoplasm as 3‘-end extended precursor (pre-snRNA), where it acquires a heptameric Sm ring. The SMN complex which catalyses this step, recruits Sm proteins and assembles them around the pre-snRNA at the single stranded Sm site. After additional modification, the complex is re-imported into the nucleus where the final maturation step occurs. Our modeling suggests that during the cytoplasmic stage of maturation pre-snRNA assumes a compact secondary structure containing Near Sm site Stem (NSS) which is not compattible with the formation of the Sm ring. To validate our in silico predictions we employed selective 2'-hydroxyl acylation analyzed by primer extension sequencing (SHAPE-Seq) on U2 snRNA in vivo, ex vivo and in vitro, and U4 pre-snRNA in vitro. For the in vivo experiment HeLa cells were incubated for 10 min at 37°C with NAI or DMSO to final concentration 200 mM. RNA was isolated using Trizol (Sigma) and 200 µl chloroform and precipitated with ethanol at -20°C overnight. For the ex vivo experiment, RNA was isolated from HeLa cells after Protease K treatment at room temperature for 45 min. After incubation, RNA was isolated using equilibrated phenol/chloroform/isoamyl alcohol buffered by folding buffer (110 mM HEPES pH 8.0, 110 mM KCl, 11 mM MgCl2) and cleaned on a PD-10 column according to the manufacturer’s instructions. Isolated RNA was treated with 100mM NAI or DMSO for 10 min at 37°C. For the in vitro experiment, U2WT and U4 pre-snRNA were transcribed by T7 polymerase followed by DNase I (30 min at 37 °C) and Proteinase K (30 min at 37°C) treatments. U2 snRNA was purified on 30 kDa Amicon columns, folded for 30 min at 37°C in 57 mM MgCl2 and incubated with 100 mM NAI at 37°C for 10 min. DMSO was used as a negative control. U4 pre-snRNA was purified on Superdex 200 Increase 10/300GL, folded for 30 min at 37°C in 60 mM MgCl2 and incubated with 100 mM NAI at 37°C for 10 min. DMSO was used as a negative control. All prepared RNA samples (in vitro, ex vivo, in vivo) were used for reverse transcription with the gene-specific primer 5’-CGTTCCTGGAGGTACTGCAA for U2 snRNA and 5’- AAAAATTCAGTCTCCG for U4 pre-snRNA. We used SHAPE MaP buffer (50 mM Tris-HCl pH 8.0, 75 mM KCl, 10 mM DTT, 0.5 mM dNTP, 6 mM MnCl2) and SuperScript II (Invitrogen). Amplicons for snRNAs were generated using gene-specific forward and reverse primers. Importantly, the primers include Nextera adaptors required for downstream library construction. PCR reaction products were cleaned using Monarch PCR&DNA Clean-up Kits. Remaining Illumina adaptor sequences were added using the PCR MasterMix and index primers provided in the NexteraXT DNA Library Preparation Kit (Illumina) according to the manufacturer’s protocol. Libraries were quantified using Qubit (Invitrogen) and BioAnalyzer (Agilent). Amplicons were sequenced on a NextSeq 500/550 platform using a 150 cycle mid-output kit. All sequencing data was analyzed using the ShapeMapper 2 analysis pipeline1. The ‘—amplicon’ and ‘—primers’ flags were used, along with sequences of gene-specific handles PCR primers, to ensure primer binding sites are excluded from reactivity calculations. Default read-depth thresholds of 5000x were used. Analysis of statistically significant reactivity differences between ex vivo and in vivo-determined SHAPE reactivities was performed using the DeltaSHAPE automated analysis tool and default settings2. 1. Busan, S. & Weeks, K.M. Accurate detection of chemical modifications in RNA by mutational profiling (MaP) with ShapeMapper 2. RNA 24, 143-148 (2018). 2. Smola, M.J., Rice, G.M., Busan, S., Siegfried, N.A. & Weeks, K.M. Selective 2'-hydroxyl acylation analyzed by primer extension and mutational profiling (SHAPE-MaP) for direct, versatile and accurate RNA structure analysis. Nat Protoc 10, 1643-69 (2015).
Project description:Analysis of 80 glioblastoma specimen of patients treated within clinical trials and 4 samples of "normal" brain tissue (non-tumoral). The data was used to identify factors of resistance to a chemoradiation therapy protocol of radiotherapy and concomitant and adjuvant temozolomide (alkylating agent). Experiment Overall Design: 80 glioblastoma specimen and 4 non-tumoral brain samples
Project description:GL261-derived glioblastoma stem cells (GSCs) form aggressive tumors when implanted into the brains of C57BL/6 mice. We used snRNA-Seq to analyze GL261 and GL261-GSCs as well as tumor samples of 7 and 28 days of development.
Project description:In this project, we isolate U1 snRNA associated proteins in Arabidopsis thaliana. We used an antisense oligonucleotide specific for the U1 snRNA and analyzed associated proteins by mass spectrometry. As a control, the same experiments were performed with U2 snRNA- and lacZ-specifc antisense oligonucleotides.
Project description:The outbreak-causing monkeypox virus of 2022 (2022 MPXV) is classified as a clade IIb strain and phylogenetically distinct from prior endemic MPXV strains (clades I or IIa), suggesting that its virological properties may also differ. Here, we used human keratinocytes and induced pluripotent stem cell-derived colon organoids to examine the efficiency of viral growth in these cells and the MPXV infection-mediated host responses. MPXV replication was much more productive in keratinocytes than in colon organoids. We observed that MPXV infections, regardless of strain, caused cellular dysfunction and mitochondrial damage in keratinocytes. Notably, a significant increase in the expression of hypoxia-related genes was observed specifically in 2022 MPXV-infected keratinocytes. Our comparison of virological features between 2022 MPXV and prior endemic MPXV strains revealed signaling pathways potentially involved with the cellular damages caused by MPXV infections and highlights host vulnerabilities that could be utilized as protective therapeutic strategies against human mpox in the future.
Project description:The World Health Organization Classification of Hematolymphoid Tumors (WHO) and the International Consensus Classification (ICC) of 2022 introduced major changes to the definition of CMML. To assess qualitative and quantitative implications for patient care, we started with 3,311 established CMML cases (according to WHO 2017 criteria) and included also 2,130 oligomonocytosis cases fulfilling the new CMML diagnostic criteria. Applying both classification systems from 2022, 356 and 241 of oligomonocytosis cases were newly classified as myelodysplastic (MD)-CMML (WHO and ICC 2022, respectively), most of which were diagnosed as MDS according to WHO 2017. Importantly, 1.5 times more oligomonocytosis cases were classified as CMML according to WHO 2022 than based on ICC, due to different diagnostic criteria. Genetic analyses of the newly classified CMML cases showed a distinct mutational profile with strong enrichment of MDS-typical alterations, resulting in a transcriptional subgroup separated from established MD- and myeloproliferative (MP)-CMML. Despite a different cytogenetic, molecular, immunophenotypic, and transcriptional landscape, no differences in overall survival were found between newly classified and established MD-CMML cases. To the best of our knowledge, this study represents the most comprehensive analysis of routine CMML cases to date, both in terms of clinical characterization and transcriptomic analysis, placing newly classified CMML cases on a disease continuum between MDS and previously established CMML.
Project description:We used snRNA-seq to investigate an entire adult mammalian heart of BL6 mice. Whole hearts were harvested from 4 male mice (12 weeks) after cervical dislocation. The hearts were pooled and nuclei isolated using the Nuclei PURE Prep isolation kit (Sigma-Aldrich, Darmstadt, Germany) according to the manufacturer’s protocol. Sequencing was conducted by Genewiz (Leipzig, Germany) on the 10xGenomics system. Single nuclei were captured in droplet emulsions and snRNA-seq libraries were constructed as per the 10x Genomics protocol using GemCode Single-Cell 3′ Gel Bead and Library V3 Kit. RNA was controlled for sufficient quality on an Agilent 2100 Bioanalyzer system and quantified using a Qubit Fluorometer.