Biology subjects

Von Kriegsheim, A.

Publications and source records attributed to Von Kriegsheim, A..

9 recordsLinked to original sources

bioRxiv2025

LIMD1 Loss Confers a GPX4-Dependent Cell State in Lung Cancer

LIMD1 (LIM domains containing 1) is a bona-fide tumour suppressor gene frequently lost during the early stages of non-small cell lung cancer (NSCLC) development, resulting in a worse outcome for LIMD1-deficient patients. LIMD1 deficiency is present in approximately 50% of NSCLC cases, representing at least 21,000 patients in the United Kingdom and 1.2 million worldwide. During cancer progression, cells can accumulate genetic changes that render them more dependent on certain genes for their survival. By performing CRISPR-Cas9 dropout screens, we identified GPX4 as a novel vulnerability in LIMD1 deficient LUAD cells. By targeting GPX4 using RNA interference (RNAi) and pharmacological intervention in our isogenic LUAD lines along with a non-transformed lung cell line, we validated GPX4 as a novel dependency in LIMD1 deficient cells. GPX4 is a key defence mechanism against ferroptosis, an iron-dependent form of regulated cell death. This state of increased ferroptosis susceptibility upon LIMD1 loss is due to increased basal reactive oxygen species levels and lipid peroxidation. Importantly, targeting GPX4 with ferroptosis inducing agents in NSCLC patients with LIMD1 loss may represent a novel therapeutic strategy.

cancer biology↗

bioRxiv2025

Dysproteostasis primes pancreatic epithelial state changes in KRAS-mediated oncogenesis

Pre-malignant transformation of pancreatic acinar cells by oncogenic Kras is dependent upon stochastic emergence of metaplastic cell states, through unknown mechanisms. We reveal that an early, transcriptionally-mediated effect of Kras is sporadic failure of proteostatic ER-phagy. Genetically-altered mice deficient in ER-phagy demonstrate that this event co-operates with Kras to drive acinar-ductal metaplasia (ADM) and subsequent cancer. Mechanistically, proteomics and high-resolution imaging uncover pathologic aggregation of a subset of ER proteins, including the injury marker REG3B, resulting from failure to physically interact with the ER-phagy receptor CCPG1. Spatial transcriptomics demonstrate that the appearance of sporadic intracellular aggregates upon Kras activation marks rare acinar cells existing in an injured, ADM-primed state. Importantly, engineered mutants of REG3B establish that aggregate formation is sufficient to directly engender this epithelial cell state. Pancreatic cancer can thus arise from stochastic pathologic protein aggregates that are influenced by and co-operate with an oncogene.

cancer biology↗

bioRxiv2024

Pharmacological inhibition of 11βhydroxysteroid dehydrogenase type 1 after myocardial infarction targets extracellular matrix processing and preserves cardiac function in a translational mini-pig model

Background and PurposePlasma glucocorticoids (GCs) increase acutely after myocardial infarction (MI), thereafter tissue levels are amplified selectively within cells expressing 11{beta}Hydroxysteroid Dehydrogenase type 1 (11{beta}HSD1) that regenerates active GCs from circulating metabolites. GCs initially protect cardiomyocytes and prevent excessive inflammation after MI but can also suppress subsequent wound repair leading to functional decline. The present study aimed to investigate the potential of pharmacological 11{beta}HSD1 inhibition after MI to prevent deterioration of cardiac function and its impact on wound repair. Experimental ApproachAdult female Gottingen mini-pigs underwent percutaneous balloon MI/reperfusion and were randomised to receive either oral 11{beta}HSD1 inhibitor AZD8329 (n=11), or vehicle (n=9), from 2 until 27 days later, with concurrent administration of clinically relevant therapeutic intervention (anti-platelet, statin and ACE inhibitor). Key ResultsAZD8329 treatment increased plasma accumulation of cortisone substrate consistent with successful 11{beta}HSD1 inhibition. Gadolinium-enhanced MRI showed equivalent infarct size in both groups prior to commencing treatment. 28 days after MI cardiac function and LV area were preserved in the AZD8329 treated group relative to vehicle. There was no impact of 11{beta}HSD1 inhibitor on neovascularisation or infarct area. Mass spectrometry imaging revealed AZD8329 binding to the healing infarct and altered regulation of extracellular matrix (ECM) processing was highlighted by birefringence microscopy and proteomic analysis. Conclusions and ImplicationsPharmacological inhibition of 11{beta}HSD1 after MI prevents deterioration of cardiac function and detrimental remodelling. 11{beta}HSD1 inhibitors have safely reached phase 2 clinical trials in diabetes and dementia and could be repurposed as an addition to standard care after MI to prevent the development of heart failure. Bullet Point Summary What is already known?O_LIGCs are released from the adrenal gland after MI, but also regenerated within the heart from circulating precursors by the enzyme 11{beta}HSD1 in cardiomyocytes, fibroblasts and macrophages. C_LIO_LIGenetic suppression of Hsd11b1 expression in the mouse promotes neovascularisation, prevents infarct expansion during infarct repair after MI and the development of heart failure. C_LI What does this study add?O_LIOral pharmacological inhibition of 11{beta}HSD1 after MI/reperfusion in a translational mini-pig model of MI receiving concurrent clinically relevant therapy prevents cardiac functional deterioration and adverse ventricular remodelling over the following 4 weeks. C_LIO_LIMass spectrometry imaging reveals target engagement of the 11{beta}HSD1i in the repairing infarct. C_LIO_LIThe mechanism is independent of neovascularisation but does involve modification of extracellular matrix remodelling during repair and scar formation. C_LI What is the clinical significance?O_LITissue 11{beta}HSD1 expression is increased in aging when the risk of MI is higher. C_LIO_LIPharmacological inhibitors of 11{beta}HSD1 have safely reached phase 2 clinical trials for dementia and metabolic disease and could be repurposed for use post-MI to prevent the development of heart failure. C_LI

pharmacology and toxicology↗

bioRxiv2024

Paralog protein compensation preserves protein-protein interaction networks following gene loss in cancer

Proteins operate within dense interconnected networks, where interactions are necessary both for stabilising proteins and for enabling them to execute their molecular functions. Remarkably, protein-protein interaction networks operating within tumour cells continue to function despite widespread genetic perturbations. Previous work has demonstrated that tumour cells tolerate perturbations of paralogs better than perturbations of singleton genes, but the mechanisms behind this genetic robustness remains poorly understood. Here, we systematically profile the proteomic response of tumours and tumour cell lines to gene loss. We find many examples of active compensation, where deletion of one paralog results in increased abundance of another, and collateral loss, where deletion of one paralog results in reduced abundance of another. Compensation is enriched among sequence-similar paralog pairs that are central in the protein-protein interaction network and widely conserved across evolution. Compensation is also significantly more likely to be observed for gene pairs with a known synthetic lethal relationship. Our results support a model whereby loss of one gene results in increased protein abundance of its paralog, stabilising the protein-protein interaction network. Consequently, tumour cells may become dependent on the paralog for survival, creating potentially targetable vulnerabilities.

systems biology↗

bioRxiv2023

Identification of a P62-TIF-IA axis that drives nucleolar fusion and the senescence associated secretory phenotype

Two key characteristics of senescent cells are nucleolar fusion and secretion of a plethora of pro-inflammatory cytokines called the senescence-associated secretory phenotype (SASP). The SASP is dependent on NF-{kappa}B but the initial trigger, and links with nucleoli, are unclear. Using multiple in vitro and in vivo models, we show that an early response to oncogene- and therapy-induced senescence (OIS and TIS) is nuclear/nucleolar accumulation of the PolI complex component, TIF-IA. This accumulation is essential for nucleolar fusion, the SASP and senescence, independent of rDNA transcription. We show that in steady state, TIF-IA is targeted for autophagic degradation by the p62 cargo receptor and that accumulation in senescence occurs as a consequence of ATM activation, which disrupts the p62-TIF-IA interaction. In mice, TIF-IA accumulates in colonic mucosa with age, which is further enhanced in the nfkb1-/- model of accelerated ageing. Together, these results reveal a p62-TIF-IA nucleolar stress axis that regulates the SASP and senescence, and that warrants further investigation as an anti-ageing target.

molecular biology↗

bioRxiv2023

Planar cell polarity is essential for the architectural patterning of the mammalian biliary tree.

In the developing liver, bipotent epithelial progenitor cells known as hepatoblasts undergo lineage segregation to form the two major epithelial cell types, hepatocytes that constitute the bulk of the liver parenchyma and biliary epithelial cells (cholangiocytes) which comprise the bile duct, a complex tubular network which is critical for normal liver function. Notch and TGF{beta} signalling promote the formation of a sheet of biliary epithelial cells, the ductal plate that organises into discontinuous tubular structures. How these structures elongate and connect to form a continuous duct remains undefined. Here, we show that the planar cell polarity protein, VANGL2 is expressed late in intrahepatic bile duct development and patterns the formation of cell-cell contacts between biliary cells. The patterning of these cell contacts regulates the normal polarisation of the actin cytoskeleton within biliary cells and loss of Vangl2-function results in the abnormal distribution of cortical actin remodelling resulting in the failure of bile duct formation. Planar cell polarity is a critical step in the post-specification sculpture of the bile duct and is essential for establishing normal tissue architecture.

developmental biology↗

bioRxiv2022

Rapid and specific degradation of endogenous proteins in mouse models using auxin-inducible degrons

Auxin-inducible degrons are a chemical genetic tool for targeted protein degradation and are widely used to study protein function in cultured mammalian cells. Here, we develop CRISPR-engineered mouse lines that enable rapid and highly specific degradation of tagged endogenous proteins in vivo. Most but not all cell types are competent for degradation. Using mouse genetics, we show that degradation kinetics depend upon the dose of the tagged protein, ligand, and the E3 ligase subunit Tir1. Rapid degradation of condensin I and condensin II - two essential regulators of mitotic chromosome structure - revealed that both complexes are individually required for cell division in precursor lymphocytes, but not in their differentiated peripheral lymphocyte derivatives. This generalisable approach provides unprecedented temporal control over the dose of endogenous proteins in mouse models, with implications for studying essential biological pathways and modelling drug activity in mammalian tissues. HighlightsO_LIAuxin-inducible degradation of endogenously tagged proteins in living mice and a range of primary cells. C_LIO_LIMost but not all cell types are competent for degradation C_LIO_LIDosage of the tagged protein, E3 ligase substrate receptor and ligand can all determine degradation kinetics C_LIO_LIRapid degradation of condensin subunits in lymphocytes reveals stage-specific requirements during cell division C_LI

genetics↗

bioRxiv2021

Nitrogen partitioning between branched-chain amino acids and urea cycle enzymes sustains renal cancer progression

Metabolic reprogramming is critical for tumor initiation and progression. However, the exact impact of specific metabolic changes on cancer progression is poorly understood. Here, we combined multi-omics datasets of primary and metastatic clonally related clear cell renal cancer cells (ccRCC) and generated a computational tool to explore the metabolic landscape during cancer progression. We show that a VHL loss-dependent reprogramming of branched-chain amino acid catabolism is required to maintain the aspartate pool in cancer cells across all tumor stages. We also provide evidence that metastatic renal cancer cells reactivate argininosuccinate synthase (ASS1), a urea cycle enzyme suppressed in primary ccRCC, to enable invasion in vitro and metastasis in vivo. Overall, our study provides the first comprehensive elucidation of the molecular mechanisms responsible for metabolic flexibility in ccRCC, paving the way to the development of therapeutic strategies based on the specific metabolism that characterizes each tumor stage. HighlightsO_LIBranched-chain amino acids catabolism is reprogrammed in ccRCC tumors C_LIO_LIBCAT-dependent transamination supplies nitrogen for de novo biosynthesis of amino acids including aspartate and asparagine in ccRCC C_LIO_LIAspartate produced downstream of BCAT is used specifically by metastatic cells through argininosuccinate synthase (ASS1) and argininosuccinate lyase (ASL) to generate arginine, providing a survival advantage in the presence of microenvironments with rate limiting levels of arginine C_LIO_LIASS1 is re-expressed in metastatic 786-M1A through epigenetic remodeling and it is sensitive to arginine levels C_LIO_LISilencing of ASS1 impairs the metastatic potential in vitro and in vivo of ccRCC cells C_LI

cancer biology↗

bioRxiv2021

Disruption of the TCA cycle reveals an ATF4-dependent integration of redox and amino acid metabolism

The Tricarboxylic Acid Cycle (TCA) cycle is arguably the most critical metabolic cycle in physiology and exists as an essential interface coordinating cellular metabolism, bioenergetics, and redox homeostasis. Despite decades of research, a comprehensive investigation into the consequences of TCA cycle dysfunction remains elusive. Here, we targeted two TCA cycle enzymes, fumarate hydratase (FH) and succinate dehydrogenase (SDH), and combined metabolomics, transcriptomics, and proteomics analyses to fully appraise the consequences of TCA cycle inhibition (TCAi) in kidney epithelial cells. Our comparative approach shows that TCAi elicits a convergent rewiring of redox and amino acid metabolism dependent on the activation of ATF4 and the integrated stress response (ISR). Furthermore, we also uncover a divergent metabolic response, whereby acute FHi, but not SDHi, can maintain asparagine levels via reductive carboxylation and maintenance of cytosolic aspartate synthesis. Our work highlights an important interplay between the TCA cycle, redox biology and amino acid homeostasis. HighlightsO_LITCA cycle inhibition promotes GSH synthesis and impairs de novo aspartate and proline synthesis C_LIO_LIDisruption of mitochondrial thiol redox homeostasis phenocopies TCA cycle inhibition by promoting GSH synthesis and impairing proline and aspartate synthesis C_LIO_LIAcute FHi, but not SDHi, can maintain asparagine levels via reductive carboxylation and maintenance of cytosolic aspartate synthesis C_LIO_LITCA cycle inhibition mimics an amino acid deprivation-type response and activates ATF4 via the integrated stress response to maintain redox and amino acid homeostasis C_LI

biochemistry↗