Biology subjects

Schmitz, M. L.

Publications and source records attributed to Schmitz, M. L..

4 recordsLinked to original sources

bioRxiv2025

High Precision Quantification of small RNA Slicing Activity - Native Index Ligation-based Targeted Degradome Sequencing (NIL-TDS)

RNA interference (RNAi) is an effective and precise regulatory mechanism in eukaryotes in which small RNAs mediate endonucleolytic slicing of complementary target mRNAs. Despite the potential of RNAi for human therapeutics and crop bio-protection, analytical platforms to quantitatively validate the slicing activities of small RNAs remain limited. Here, we present NIL-TDS, a cost-effective method that combines RNA ligase-mediated PCR with Nanopore Sequencing for direct, rapid, and high-resolution detection and quantification of sRNA-mediated slicing events. Using NIL-TDS, we quantitatively detected minute changes in Ath-mir400 mediated slicing of PPR1 in heat and salt stressed Arabidopsis plants. We further demonstrate the broader applicability of NIL-TDS by detecting rare slicing events in a mammalian system. Of relevance for malignancy of certain cancers, and tumor progression and metastasis, NIL-TDS further confirmed miR-196-HOXB8 interactions in lung cancer cells and discovered a novel miR-7162-HOXA10-AS slicing site. These findings demonstrate the sensitivity of NIL-TDS for uncovering small RNA mediated regulatory mechanisms of gene expression and disease progression in eukaryotes. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=83 SRC="FIGDIR/small/679503v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@adef35org.highwire.dtl.DTLVardef@1339570org.highwire.dtl.DTLVardef@1980652org.highwire.dtl.DTLVardef@1c732ef_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2025

Synergistic targeting of cancer cells through simultaneous inhibition of key metabolic enzymes

As cancer cell specific rewiring of metabolic networks creates potential therapeutic opportunities, we conducted a synthetic lethal screen utilizing inhibitors of metabolic pathways. Simultaneous administration of (R)-GNE-140 and BMS-986205 (Linrodostat) preferentially halted proliferation of ovarian cancer cells, but not of their non-oncogenically transformed progenitor cells. While (R)-GNE-140 inhibits lactate dehydrogenase (LDH)A/B and thus effective glycolysis, BMS-986205, in addition to its known inhibitory activity on Indoleamine 2,3-dioxygenase (IDO1), also restricts oxidative phosphorylation (OXPHOS), as revealed here. BMS-986205, which is being tested in multiple Phase III clinical trials, inhibits the ubiquinone reduction site of respiratory complex I and thus compromises mitochondrial ATP production. The energetic catastrophe caused by simultaneous interference with glycolysis and OXPHOS resulted in either cell death or the induction of senescence in tumor cells, with the latter being eliminated by senolytics. The frequent synergy observed with combined inhibitor treatment was comprehensively confirmed through testing on tumor cell lines from the DepMap panel and on human colorectal cancer organoids. These experiments revealed highly synergistic activity of the compounds in a third of the tested tumor cell lines, correlating with alterations in genes with known roles in metabolic regulation and demonstrating the therapeutic potential of metabolic intervention.

cancer biology↗

bioRxiv2024

The proximity-based protein interaction landscape of the transcription factor p65 NF-kappaB/RELA and its gene-regulatory logics

The protein interactome of p65 / RELA, the most active subunit of the transcription factor (TF) NF-{kappa}B, has not been previously determined in living cells. Using p65-miniTurbo fusion proteins, we identified by biotin tagging > 350 RELA interactors from untreated and IL-1-stimulated cells, including many TFs (47 % of all interactors) and > 50 epigenetic regulators belonging to different classes of chromatin remodeling complexes. According to point mutants of p65, the interactions primarily require intact dimerization rather than DNA binding properties. A targeted RNAi screen for 38 interactors and subsequent functional transcriptome and bioinformatics studies identified gene regulatory (sub)networks, each controlled by RELA in combination with one of the TFs ZBTB5, GLIS2, TFE3 / TFEB or S100A8 / A9. The remarkably large, dynamic and versatile high resolution interactome of RELA and its gene-regulatory logics provides a rich resource and a new framework for explaining how RELA cooperativity determines gene expression patterns. HighlightsO_LIIdentification of > 350 largely dimerization-dependent interactors of p65 / RELA by miniTurboID C_LIO_LIThe interactome is dominated by transcription factors and epigenetic regulator complexes C_LIO_LIFunctional validation of 38 high confidence interactors by targeted siRNA screen C_LIO_LIIdentification of genetic networks regulated by RELA and six of its interactors in the IL-1 response C_LI

molecular biology↗

bioRxiv2020

Inhibiting coronavirus replication in cultured cells by chemical ER stress

Coronaviruses (CoVs) are important human pathogens for which no specific treatment is available. Here, we provide evidence that pharmacological reprogramming of ER stress pathways can be exploited to suppress CoV replication. We found that the ER stress inducer thapsigargin efficiently inhibits coronavirus (HCoV-229E, MERS-CoV, SARS-CoV-2) replication in different cell types, (partially) restores the virus-induced translational shut-down, and counteracts the CoV-mediated downregulation of IRE1 and the ER chaperone BiP. Proteome-wide data sets revealed specific pathways, protein networks and components that likely mediate the thapsigargin-induced antiviral state, including HERPUD1, an essential factor of ER quality control, and ER-associated protein degradation complexes. The data show that thapsigargin hits a central mechanism required for CoV replication, suggesting that thapsigargin (or derivatives thereof) may be developed into broad-spectrum anti-CoV drugs. One Sentence Summary / Running titleSuppression of coronavirus replication through thapsigargin-regulated ER stress, ERQC / ERAD and metabolic pathways

immunology↗