Biology subjects

Kuttler, F.

Publications and source records attributed to Kuttler, F..

6 recordsLinked to original sources

bioRxiv2026

Aggregate Deep Visual Proteomics reveals selective organization of α-synuclein inclusions

-Synuclein inclusions, the lesions typical of Parkinson's disease, have been interpreted as protective deposits, toxic species or failed degradation products, each predicting a different composition and correlating that enrichment with neuron dysfunction and eventual degeneration. Distinguishing them requires measuring what an inclusion concentrates relative to the cell that built it. Here we developed Aggregate Deep Visual Proteomics, which uses ultrasensitive mass spectrometry to profile laser-microdissected inclusions against the remainder of the same cell or a matched host. In HEK293 cells, iPSC-derived dopaminergic neurons and post-mortem patient brain, each inclusion concentrated a selective subset of its cell's proteome, independent of abundance and dominated by membrane, in neurons largely presynaptic. Inclusions took up whole assemblies, with subunits moving together in 421 of 438 complexes, and the V-ATPase alone was enriched in all three systems. Degradation cargo stayed with the receptors that route it, consistent with sequestration and failed degradation acting together. Neuritic and somatic inclusions differed, the former rich in UBQLN2 and the latter in intermediate filaments. In the cell line, phosphorylated -synuclein was tenfold higher in the inclusion than in the rest of the cell, with about one third of the rise already present before an inclusion was visible. Measured against its host, the composition of an inclusion becomes a readout of how it formed and a source of candidate markers and therapeutic targets.

biochemistry↗

bioRxiv2023

Repression of Aurora kinase B prevents growth and tissue invasion in medulloblastoma

Novel treatment strategies are required to overcome therapy-associated sequelae in survivors of pediatric medulloblastoma (MB) while maintaining therapeutic efficacy. The tissue impact on drug response in MB is not well understood and drug profiling in the physiological context of the tissue may reveal novel therapy targets. To gain insights into the growth and dissemination behavior of the MB tumor cells under treatment, we combined three-dimensional cell culture screening with ex vivo organotypic cerebellum slice co-culture (OCSC), which allowed assessing tumor cell behavior in the tissue context. We screened a panel of 274 kinase inhibitors and identified aurora kinase B (AURKB) as a potential anti-invasion drug target in MB. We validated tumor suppressive activities of the AURKB inhibitor (AURKBi) barasertib and the structurally unrelated compound GSK-1070916 in cerebellum slice culture models for SHH, Grp3 and Grp4 MB at nanomolar concentrations. We confirmed the necessity of AURKB for tumor growth through genetic suppression of AURKB by siRNA in the tissue context. We revealed that the combination of AURKBi with the SRC/BCR-ABL inhibitor dasatinib acts synergistically to repress tumor growth and invasiveness in the SHH MB cell model ONS76, but not in Grp3 MB cells. Finally, we demonstrate that pharmacological repression of AURKB in the tissue context is as effective as X-ray irradiation to repress tumor growth. Our data highlight that AURKBi is equally efficient as irradiation, suggesting that pharmacological targeting of AURKB may constitute a novel means to overcome radiotherapy limitations in patients younger than three years. Importance of the studyOur data demonstrate anti-tumor activity of AURKB inhibitors in the tissue context for MB tumor cells that are in vitro resistant to the treatment. This indication of a tissue component to drug response contributes critical insights for drug response profiling for brain tumors. AURKB inhibitors barasertib and GSK-1070916 block growth and invasiveness of SHH, Grp3 and Grp4 MB tumor cells as well as primary ATRT. Importantly, AURKBi is equally efficient as irradiation. In conclusion, a tissue component contributes to sensitivity to AURKB inhibition and pharmacological targeting of AURKB may constitute a novel means to overcome radiotherapy limitations in patients younger than three years. Key pointsO_LIAURKB is essential for in tissue growth of MB. C_LIO_LIInactivation of AURKB causes p53 upregulation and decreased in tissue growth and dissemination. C_LIO_LIAURKB inhibition in the tissue context is as effective as irradiation to restrict tumor cell growth. C_LI

cancer biology↗

bioRxiv2021

Arrayed multicycle drug screens identify broadly acting chemical inhibitors for repurposing against SARS CoV 2

Coronaviruses (CoVs) circulate in humans and animals, and expand their host range by zoonotic and anthroponotic transmissions. Endemic human CoVs, such as 229E and OC43 cause limited respiratory disease, and elicit short term anti-viral immunity favoring recurrent infections. Yet, severe acute respir-atory syndrome (SARS)-CoV-2 spreads across the globe with unprecedented impact on societies and economics. The world lacks broadly effective and affordable anti-viral agents to fight the pandemic and reduce the death toll. Here, we developed an image-based multicycle replication assay for focus for-mation of -coronavirus hCoV-229E-eGFP infected cells for screening with a chemical library of 5440 compounds arrayed in 384 well format. The library contained about 39% clinically used compounds, 26% in phase I, II or III clinical trials, and 34% in preclinical development. Hits were counter-selected against toxicity, and challenged with hCoV-OC43 and SARS-CoV-2 in tissue culture and human bronchial and nasal epithelial explant cultures from healthy donors. Fifty three compounds inhibited hCoV-229E-GFP, 39 of which at 50% effective concentrations (EC50) < 2M, and were at least 2-fold separated from toxicity. Thirty nine of the 53 compounds inhibited the replication of hCoV-OC43, while SARS-CoV-2 was inhibited by 11 compounds in at least two of four tested cell lines. Six of the 11 compounds are FDA-approved, one of which is used in mouth wash formulations, and five are systemic and orally available. Here, we demonstrate that methylene blue (MB) and mycophenolic acid (MPA), two broadly available low cost compounds, strongly inhibited shedding of infectious SARS-CoV-2 at the apical side of the cultures, in either pre- or post-exposure regimens, with somewhat weaker effects on viral RNA release indicated by RT-qPCR measurements. Our study illustrates the power of full cycle screens in repurposing clinical compounds against SARS-CoV-2. Importantly, both MB and MPA reportedly act as immunosuppressants, making them interesting candidates to counteract the cytokine storms affecting COVID-19 patients.

microbiology↗

bioRxiv2020

The FDA-approved drug Nelfinavir inhibits lytic cell-free transmission of human adenoviruses

Adenoviruses (AdVs) are prevalent and give rise to chronic and recurrent disease. The human AdV (HAdV) species B and C, such as HAdV-C2, C5 and B14, cause respiratory disease, and constitute a health threat for immuno-compromised individuals. HAdV-Cs are well known for lysing cells, owing to the E3 CR1-{beta}-encoded adenovirus death protein (ADP). We previously reported a high-throughput image-based screening framework and identified an inhibitor of HAdV-C2 multi-round infection, Nelfinavir Mesylate. Nelfinavir is the active ingredient of Viracept, an FDA-approved inhibitor of the human immuno-deficiency virus (HIV) aspartyl protease, and used to treat acquired immunodeficiency syndrome (AIDS). It is not effective against single round HAdV infections. Here, we show that Nelfinavir inhibits the lytic cell-free transmission of HAdV, indicated by the suppression of comet-shaped infection foci in cell culture. Comet-shaped foci occur upon convection-based transmission of cell-free viral particles from an infected cell to neighbouring uninfected cells. HAdV lacking ADP was insensitive to Nelfinavir, but gave rise to comet-shaped foci indicating that ADP enhances but is not required for cell lysis. This was supported by the notion that HAdV-B14 and B14p1 lacking ADP were highly sensitive to Nelfinavir, although HAdV-A31, B3, B7, B11, B16, B21, D8, D30 or D37 were less sensitive. Conspicuously, Nelfinavir uncovered slow-growing round-shaped HAdV-C2 foci, independent of neutralizing antibodies in the medium, indicative of non-lytic cell-to-cell transmission. Our study demonstrates the repurposing potential of Nelfinavir with post-exposure efficacy against different HAdVs, and describes an alternative non-lytic cell-to-cell transmission mode of HAdV. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/098061v1_ufig1.gif" ALT="Figure 1"> View larger version (85K): org.highwire.dtl.DTLVardef@8aa32corg.highwire.dtl.DTLVardef@1dea943org.highwire.dtl.DTLVardef@13aa2fborg.highwire.dtl.DTLVardef@a23352_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1.C_FLOATNO C_FIG

microbiology↗

bioRxiv2020

A full cycle anti-viral drug screen identifies a clinical compound against adenovirus infection

Human adenoviruses (HAdVs) are fatal to immuno-suppressed people, but no effective anti-HAdV therapy is available. Here, we present a novel image-based high-throughput screening (HTS) platform, which scores the full viral replication cycle from virus entry to dissemination of progeny. We analysed 1,280 small molecular weight compounds of the Prestwick Chemical Library (PCL) for interference with HAdV-C2 infection in a quadruplicate, blinded format, and included robust image analyses, and hit filtering. We present the entire set of the screening data including all the images, image analyses and data processing pipelines. The data are made available at the Image Data Repository (IDR) 1, accession number idr0081. Our screen identified Nelfinavir mesylate as an inhibitor of HAdV-C2 multi-round plaque formation, but not single round infection. Nelfinavir has been FDA-approved for anti-retroviral therapy in humans. Our results underscore the power of image-based full cycle infection assays in identifying viral inhibitors with clinical potential.

microbiology↗

bioRxiv2019

The process of Lewy body formation, rather than simply alpha-synuclein fibrillization, is the major driver of neurodegeneration in synucleinopathies

Parkinsons disease (PD) is characterized by the accumulation of misfolded alpha-synuclein (-syn) into intraneuronal inclusions named Lewy bodies (LB). Although it is widely believed that -syn plays a central role in the pathogenesis of PD and synucleinopathies, the processes that govern -syn fibrillization and LB formation in the brain remain poorly understood. In this work, we sought to reverse engineer LBs and dissect the spatiotemporal events involved in their biogenesis at the genetic, molecular, biochemical, structural, and cellular levels. Toward this goal, we took advantage of a seeding-based model of -syn fibril formation in primary neurons and further developed this model to generate the first neuronal model that reproduces the key events leading to LB formation; including seeding, fibrillization, and the formation of LB-like inclusions that recapitulate many of the biochemical, structural, and organizational features of LBs found in post-mortem human PD brain tissues. Next, we applied an integrative approach combining confocal and correlative light-electron microscopy (CLEM) imaging methods with biochemical profiling of -syn species and temporal proteomic and transcriptomic analyses to dissect the molecular events associated with LB formation and maturation and to elucidate their contributions to neuronal dysfunctions and neurodegeneration in PD and synucleinopathies. The results from these studies demonstrate that LB formation involves a complex interplay between -syn fibrillization, post-translational modifications, and interactions between -syn aggregates and membranous organelles, including mitochondria and the autophagosome and endolysosome. Furthermore, we demonstrate that the process of LB formation and maturation, rather than simply fibril formation, is the major driver of neurodegeneration through disruption of cellular functions and inducing mitochondria damage and deficits, as well as synaptic dysfunctions. Having a neuronal model that allows for unlinking of the key processes involved in LB formation is crucial for elucidating the molecular and cellular determinants of each process and their contributions to neuronal dysfunction and degeneration in PD and synucleinopathies. Such a model is essential to efforts to identify and investigate the mode of action and toxicity of drug candidates targeting -syn aggregation and LB formation.

neuroscience↗