bioRxiv Science⌕ Search

Biology subjects

Renner, S.

Publications and source records attributed to Renner, S..

12 recordsLinked to original sources

A high-throughput compound screen identifies multiple druggable targets in Plasmodium falciparum transmission stages

Most antimalarials are ineffective against the sexual transmission stages, known as gametocytes, of the malaria parasite Plasmodium falciparum. Their low sensitivity to drugs is attributed to limited compound uptake and a poorly understood form of cellular quiescence. Our current understanding of druggable transmission-blocking processes is therefore limited. Based on genetically engineered parasites that facilitate the mass production of synchronous mature gametocytes, we developed a high throughput drug screening platform that allowed us to test more than 50,000 compounds for gametocytocidal effects in one day. By screening a diversity-oriented library, we identified over 40 molecules that kill mature gametocytes in the low nanomolar range. Using resistance selection coupled to whole genome sequencing and drug-target interaction modelling, we followed up on three chemically tractable compounds that are also highly active against asexual parasites and prevent gametocyte transmission to mosquitoes. We show that the compound ONX-0914, a specific inhibitor of the {beta}5i/LMP7 subunit of human immunoproteasomes, targets the parasite proteasomal {beta}5 subunit. In contrast, the compounds CR-1-31-B and brusatol interfere with translation by targeting eukaryotic initiation factor 4A (eIF4A) and the peptidyl transferase center (PTC) of the 80S ribosome, respectively. Interestingly, parasite resistance to brusatol, a broad-spectrum antitumor drug, is linked to the differential modification of specific rRNA bases near the ribosomal A-site, mediated by altered base specificity of a rRNA methyltransferase. In summary, we successfully combined high-throughput compound screening with drug target deconvolution to reveal the targets and mode-of-action for three potent gametocytocidal molecules and discover the mechanism of resistance to the anti-tumorigenic drug brusatol. In addition to critically advancing our understanding of mature gametocyte biology and druggable processes in P. falciparum transmission stages, our observations made with brusatol-resistant parasites may become relevant for anti-cancer drug research.

molecular biology↗

The road to nowhere: geolocation-by-genotype traces large-scale yellow-browed warbler vagrancy to central Siberia

Vagrant animals - individuals found far outside their normal range - offer powerful natural experiments for understanding migratory mechanisms. The yellow-browed warbler (Phylloscopus inornatus) provides perhaps the best-yet example, typically migrating from Siberia to South/Southeast Asia yet found in increasingly large numbers in Western Europe. This represents a strikingly unresolved evolutionary puzzle: why do so many migrants consistently move in almost the complete wrong direction? A critical first step toward solving this enigma is determining where these birds come from. If vagrants came from the proximal western range edge this would imply simple disorientation, whilst a more easterly origin could imply large-scale reverse misorientation. Here, we develop a geolocation-by-genotype algorithm for low-coverage whole-genome resequencing data collected from feathers. Our method identifies spatially informative SNPs; clusters them to account for covariance in allele frequency through space; and employs a bootstrapped maximum-likelihood framework to estimate spatial origin with uncertainty. Applied to more than 80 European-caught birds, our results place their origin in central Siberia (118{degrees}E; 89-134{degrees}E [95% CI]); over 2000km east of the western range edge. These results suggest mass misorientation in a near-reverse direction, and highlight the yellow-browed warbler as an exceptional system for probing the mechanism, ontogeny and evolution of migration.

animal behavior and cognition↗

Screening of a chemogenetic library unveils dual-stage antimalarials with low cytotoxicity

The global effort to eradicate malaria requires the development of drugs with novel mechanisms of action and differentiated pharmacological profiles. Both liver and blood phases of Plasmodium infection are essential for disease progression and transmission, making them primary targets for therapeutic intervention. In this study, we established a dual-luciferase reporter assay to simultaneously assess Plasmodium berghei liver-stage development and host cell viability. Screening a library of bioactive small molecules with annotated human targets revealed several inhibitors with potent liver-stage activity and minimal cytotoxicity. Further profiling against P. falciparum asexual blood stages identified compounds with dual-stage activity, underscoring their potential utility for development as either prophylactic or therapeutic agents. Knowledge of their human targets will facilitate investigation into host- or parasite- directed antimalarial mechanisms, thereby accelerating both biological insight and rational drug development. Our findings constitute a valuable resource for research on malaria biology and the discovery of next-generation antimalarials.

microbiology↗

Accounting for spatial interactions in the upscaling of ecosystem services

O_LIMaps of ecosystem service (ES) supply are frequently used to guide spatial planning, policy making, and ecosystem management. However, these are typically based upon coarse land-cover proxies. This approach lacks a strong mechanistic basis, and neglects spatial biodiversity dynamics and interactions among landscape properties that can modify ES provision. C_LIO_LIWe present an analytical framework for ES upscaling that incorporates spatial interactions between landscape properties to determine ES supply. The resulting models can be viewed as a spatially informed ES production function. The approach comprises seven steps that include several elements absent from most existing approaches, notably a procedure for identifying geodata variables that represent the true mechanistic drivers, the inclusion of spatial interactions in the upscaling model, and modification following expert feedback on the selected model. C_LIO_LIWe demonstrate the approach using two example ES from German grasslands: biodiversity conservation and water supply. We show that the inclusion of spatial interactions in the upscaling model improved model predictions from 15% to 33% depending on the ES evaluated. In addition, inclusion of spatial interactions led to reduced error associated with the upscaled estimates. C_LIO_LIBy overcoming several shortcomings of existing, upscaling approaches we generate resulting maps of ES supply that can more reliably inform spatial planning Further, the underlying models allow for simulation of changes in the drivers of ES supply and estimation of respective outcomes. These advantages have the potential to better link detailed local-scale ecological understanding and land management with large-scale ES supply mapping, and thus better inform decision making and spatial planning. C_LI

ecology↗

Benchmarking porcine pancreatic ductal organoids for drug screening applications

Primary human pancreatic ductal organoids (HPDO) have emerged as a model to study pancreas biology and disease. Yet, donor material availability, and a lack of extensive benchmarking limits the range of applications. To address this gap, we established porcine pancreatic ductal organoids (PPDO) as a system from an easily obtainable source to model pancreatic ductal/progenitor biology. We benchmarked PPDO to HPDO and primary porcine pancreas using single-cell RNA sequencing (scRNA-Seq). We observed no overt phenotypic differences in PPDO derived from distinct developmental stages, with a WNT signaling enriched population characterizing PPDO. PPDO exhibited differentiation potential towards mature ductal cells and limited potential towards endocrine lineages. We used PPDO as a platform to assess the safety of FDA-approved drugs and showed conserved toxicity of statins and -adrenergic receptor inhibitors between PPDO and HPDO cultures. Overall, our results highlight the PPDO as a model for mammalian duct/progenitor applications.

developmental biology↗

Cell type-focused compound screen in human organoids reveals molecules and pathways controlling cone photoreceptor death

Human organoids that mirror their corresponding organs in cell-type diversity present an opportunity to perform large-scale screens for compounds that protect disease-affected or damage healthy cell types. However, such screens have not yet been performed. Here, we generated 20,000 human retinal organoids with GFP-labeled cone photoreceptors. Since degeneration of cones is a leading cause of blindness, we induced cone death and screened 2,707 compounds with known targets, for those that saved cones or those that further damaged cones. We identified inhibitors of CK1 or MAPK11 that protected cones, HSP90 inhibitors that saved cones in the short term but damaged them in the longer term, and broad HDAC inhibition by many compounds that significantly damaged cones. This work provides a database for cone-damaging compounds and describes compounds that can be starting points to develop neuroprotection for cones in diseases such as macular degeneration.

neuroscience↗

Screening in serum-derived medium reveals differential response to compounds targeting metabolism

INTRODUCTION INTRODUCTION RESULTS DISCUSSION KEY RESOURCES TABLE CONTACT FOR REAGENT AND... EXPERIMENTAL MODEL AND SUBJECT... METHOD DETAILS QUANTIFICATION AND STATISTICAL... Data resources DATA AND SOFTWARE AVAILABILITY AUTHOR CONTRIBUTIONS DECLARATION OF INTERESTS REFERENCES Studies of cancer cells in standard culture conditions have long been used as a tractable tool for drug discovery. Cell culture provides unparalleled experimental flexibility, scalability, and low cost to identify and understand the response to cancer therapeutics; however, drug responses in culture are not always predictive of drug response in animal models or in patients1 ...

cancer biology↗

Tyrosine kinase inhibitors trigger lysosomal damage-associated cell lysis to activate the NLRP3 inflammasome

Inflammasomes are intracellular protein complexes that control proteolytic maturation and secretion of inflammatory interleukin-1 (IL-1) family cytokines and are thus important in host defense. While some inflammasomes are activated simply by binding to pathogen-derived molecules, others, including those nucleated by NLRP3 and NLRP1, have more complex activation mechanisms that are not fully understood. We screened a library of small molecules to identify new inflammasome activators that might shed light on activation mechanisms. In addition to validating dipeptidyl peptidase (DPP) inhibitors as NLRP1 activators, we find that clinical tyrosine kinase inhibitors (TKIs) including imatinib and masitinib activate the NLRP3 inflammasome. Mechanistically, these TKIs cause lysosomal swelling and damage, leading to cathepsin-mediated destabilization of myeloid cell membranes and cell lysis. This is accompanied by potassium (K+) efflux, which activates NLRP3. Both lytic cell death and NLRP3 activation but not lysosomal damage induced by TKIs are prevented by the cytoprotectant high molecular weight polyethylene glycol (PEG). Our study establishes a screening method that can be expanded for inflammasome research and immunostimulatory drug development, and provides new insight into immunological off-targets that may contribute to efficacy or adverse effects of TKIs. One Sentence SummaryA functional small molecule screen identifies imatinib, masitinib and other tyrosine kinase inhibitors that destabilize myeloid cell lysosomes, leading to cell lysis and K+ efflux-dependent NLRP3 inflammasome activation.

immunology↗

DRUG-seq Provides Unbiased Biological Activity Readouts for Drug Discovery

Unbiased transcriptomic RNA-seq data has provided deep insights about biological processes. However, its impact in drug discovery has been narrow given high costs and low throughput. Proof-of-concept studies with Digital RNA with pertUrbation of Genes (DRUG)-seq demonstrated the potential to address this gap. We extended the DRUG-seq platform by subjecting it to rigorous testing and by adding an open-source analysis pipeline. The results demonstrate high reproducibility and ability to resolve the mechanism(s) of action for a diverse set of compounds. Overall, the protocol and open-source analysis pipeline are a step towards industrializing RNA-seq for high complexity transcriptomics studies performed at a saturating scale.

genomics↗

Sequential in vivo labeling of insulin secretory granule pools in INS-SNAP transgenic pigs

{beta}-cells produce, store and secrete insulin upon elevated blood glucose levels. Insulin secretion is a highly regulated process. The probability for insulin secretory granules to undergo fusion with the plasma membrane or being degraded is correlated with their age. However, the molecular features and stimuli connected to this behavior have not yet been fully understood. Furthermore, our understanding of {beta}-cell function is mostly derived from studies of ex vivo isolated islets and/or rodent models. To overcome this translational gap and study insulin secretory granule turnover in vivo, we have generated a transgenic pig model with the SNAP-tag fused to insulin. We demonstrate the correct targeting and processing of the tagged insulin and normal glycemic control of the pig model. Furthermore, we show specific single- and dual-color granular labeling of in vivo labeled pig pancreas. This model may provide unprecedented insights into the in vivo insulin secretory granule behavior in an animal close to humans.

cell biology↗

Chronic hyperglycaemia drives functional impairment of lymphocytes in diabetic INSC94Y transgenic pigs

People with diabetes mellitus have an increased risk for infections, however, there is still a critical gap in precise knowledge about altered immune mechanisms in this disease. Since diabetic INSC94Y transgenic pigs exhibit elevated blood glucose and a stable diabetic phenotype soon after birth, they provide a favourable model to explore functional alterations of immune cells in an early stage of diabetes mellitus in vivo. Hence, we investigated peripheral blood mononuclear cells (PBMC) of these diabetic pigs compared to non-transgenic wild-type littermates. We found a 5-fold decreased proliferative response of T cells in INSC94Y tg pigs to polyclonal T cell mitogen phytohaemagglutinin (PHA). Using label-free LC-MS/MS, a total of 2,704 proteins were quantified, and distinct changes in protein abundances in CD4+ T cells of early-stage diabetic pigs were detectable. Additionally, we found significant increases in mitochondrial oxygen consumption rate (OCR) and higher basal glycolytic activity in PBMC of diabetic INSC94Y tg pigs, indicating an altered metabolic immune cell phenotype in diabetics. Thus, our study provides new insights into molecular mechanisms of dysregulated immune cells triggered by permanent hyperglycaemia.

immunology↗

Gene-signatures predict biologically relevant dose-response potencies in phenotypic assays

Multiplexed gene-signature-based phenotypic assays are increasingly used for the identification and profiling of small molecule-tool compounds and drugs. Here we introduce a method (provided as R-package) for the quantification of the dose-response potency of a gene-signature as EC50 and IC50 values.\n\nTwo signaling pathways were used as models to validate our methods: beta-adrenergic agonistic activity on cAMP generation (dedicated dataset generated for this study) and EGFR inhibitory effect on cancer cell viability. In both cases, potencies derived from multi-gene expression data were highly correlated with orthogonal potencies derived from cAMP and cell growth readouts, and superior to potencies derived from single individual genes.\n\nOur results show that gene-signature potencies are a novel valid alternative to conventional readouts for compound potency quantification, in particular in scenarios where no other established readouts are available.

bioinformatics↗