Biology subjects

Lagies, S.

Publications and source records attributed to Lagies, S..

6 recordsLinked to original sources

bioRxiv2026

The microbiome determines the phenotype in CTLA-4 insufficient mice and men

CTLA-4 (haplo)insufficiency displays incomplete penetrance and phenotypic heterogeneity, indicating the involvement of additional disease modifiers beyond the genetic defect. Microbiome analyses reveal a positive association between disease severity and intestinal dysbiosis, highlighting the microbiome as a critical contributor. To investigate this relationship mechanistically, we generated Ctla4/- wildlings harboring a natural microbiota. Unlike specific pathogen free (SPF) counterparts, which remain healthy, Ctla4/- wildlings spontaneously develop disease phenotypes resembling human CTLA-4 haploinsufficiency. Disease onset is followed by reduced microbial diversity and expansion of pathobionts. Integrative immunophenotyping shows that the natural microbiota synergizes with Ctla4 haploinsufficiency to reshape innate and adaptive immune compartments, generating a sustained pro-inflammatory milieu and reduced CTLA-4 expression in the cecum. Furthermore, microbiota-derived metabolites promote inflammatory cytokine production in both murine and human primary T cells via NF-{kappa}B activation. Collectively, Ctla4/- wildlings constitute an effective model for dissecting microbiome-immune crosstalk in CTLA-4 (haplo)insufficiency and for exploring therapeutic strategies.

immunology↗

bioRxiv2026

Lipotoxic fingerprints in clinically relevant postoperative pancreatic fistula: fatty acid driven cytotoxicity targets cells involved in anastomotic healing

Background & AimsClinically relevant postoperative pancreatic fistula (CR-POPF) remains a major cause of morbidity following pancreatic surgery, potentially due to fatty acid release by lipase activity. This study investigated how the biochemical composition of CR-POPF effluents drives cellular injury and transcriptional stress responses. MethodsDrain effluents from 14 patients undergoing pancreatoduodenectomy (7 with CR-POPF and 7 controls) were analyzed using gas chromatography-mass spectrometry. Candidate lipids were tested on human foreskin fibroblasts, mesothelial cells, and pancreatic epithelial cells using viability and cytotoxicity assays. Effluents were applied directly to cultures, and RNA sequencing was performed on cells exposed to the two most cytotoxic CR-POPF samples. ResultsMetabolomic profiling revealed lipolytic traits characterized by long-chain saturated fatty acids, including palmitic and stearic acid, and the palmitic acid monoacylglycerol monopalmitin, in drain effluents. These fatty acids accounted for over 70% of the variance in multivariate metabolomic analyses between CR-POPF and control groups. Dose-response assays confirmed concentration-dependent cytotoxicity (p < 0.0001), with a subtoxic threshold of 0.2 mM. Two effluents (AES1448 and GR1479) consistently reduced cell viability across models (F > 19, p < 0.0001). Transcriptomic profiling showed enrichment of inflammatory, unfolded-protein, and stress-response pathways, along with suppression of proliferation modules. GR1479 induced metabolic adaptation, whereas AES1448 and monopalmitin triggered overt lipotoxic stress. ConclusionsLipolysis-derived lipids may mediate stromal and mesothelial injury in CR-POPF. Integrating metabolomic, functional, and transcriptomic data uncovers a spectrum of cellular responses, spanning from adaptive remodeling to lipolysis-driven proteotoxic stress. These findings support lipid toxicity as a biochemical property of CR-POPF and a potential target for prevention. SynopsisThis study identifies long-chain saturated fatty acids in postoperative pancreatic effluents as key mediators of cytotoxic and inflammatory stress. Integrating metabolomic and transcriptomic analyses link effluent composition directly to cellular injury and impaired healing after pancreatic surgery. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=72 SRC="FIGDIR/small/705517v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@2ba175org.highwire.dtl.DTLVardef@752522org.highwire.dtl.DTLVardef@d8f823org.highwire.dtl.DTLVardef@8acb7f_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG

cell biology↗

bioRxiv2023

A universal preservation protocol for multi-omic and histological analysis of kidney tissue

Biobanking of tissue from clinically obtained kidney biopsies for later use with multi-omic and imaging techniques is an inevitable step to overcome the need of disease model systems and towards translational medicine. Hence, collection protocols ensuring integration into daily clinical routines using preservation media not requiring liquid nitrogen but instantly preserving kidney tissue for clinical and scientific analyses are of paramount importance. Thus, we modified a robust single nucleus dissociation protocol for kidney tissue stored snap frozen or in the preservation media RNAlater and CellCover. Using porcine kidney tissue as surrogate for human kidney tissue, we conducted single nucleus RNA sequencing with the Chromium 10X Genomics platform. The resulting data sets from each storage condition were analyzed to identify any potential variations in transcriptomic profiles. Furthermore, we assessed the suitability of the preservation media for additional analysis techniques (proteomics, metabolomics) and the preservation of tissue architecture for histopathological examination including immunofluorescence staining. In this study, we show that in daily clinical routines the RNAlater facilitates the collection of highly preserved kidney biopsies and enables further analysis with cutting-edge techniques like single nucleus RNA sequencing, proteomics, and histopathological evaluation. Only metabolome analysis is currently restricted to snap frozen tissue. This work will contribute to build tissue biobanks with well-defined cohorts of the respective kidney disease that can be deeply molecularly characterized, opening new horizons for the identification of unique cells, pathways and biomarkers for the prevention, early identification, and targeted therapy of kidney diseases.

genomics↗

bioRxiv2021

Photoaffinity capture compounds to profile the Magic Spot Nucleotide interactomes

Magic Spot Nucleotides (MSN) regulate the stringent response, a highly conserved bacterial stress adaptation mechanism, enabling survival when confronted with adverse external challenges. In times of antibiotic crisis, a detailed understanding of the stringent response is of critical importance, as potentially new targets for pharmacological intervention could be identified. In this study, we delineate the MSN interactome in Escherichia coli and Salmonella typhimurium cell lysates applying a family of trifunctional photoaffinity capture compounds. We introduce different MSN probes covering diverse phosphorylation patterns, such as pppGpp, ppGpp, and pGpp. Our chemical proteomics approach provides datasets of diverse putative MSN receptors both from cytosolic and membrane fractions that, upon validation, unveil new MSN targets. We find, for example, that the dinucleoside polyphosphate hydrolase activity of the non-Nudix hydrolase ApaH is potently inhibited by pppGpp, which itself is converted to pGpp by ApaH. The photoaffinity capture compounds described herein will be useful to identify MSN interactomes under varying conditions and across bacterial species. TOC O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=44 SRC="FIGDIR/small/472736v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@15cfc02org.highwire.dtl.DTLVardef@1a4ec1borg.highwire.dtl.DTLVardef@88fd27org.highwire.dtl.DTLVardef@1a42248_HPS_FORMAT_FIGEXP M_FIG Molecular fishing: a family of trifunctional photoaffinity capture compounds enables the identification of Magic Spot Nucleotide receptors by a chemoproteomics approach. C_FIG

biochemistry↗

bioRxiv2020

The Gb3-enriched CD59/flotillin plasma membrane domain regulates host cell invasion by Pseudomonas aeruginosa

The opportunistic pathogen Pseudomonas aeruginosa is responsible for a high number of acute and chronic hospital-acquired infections. As it develops more and more resistances against existing antibiotics, P. aeruginosa has been placed highest on the global priority list of antibiotic-resistant bacteria for which alternative treatments are urgently needed. Former studies have highlighted the crucial role of the bacterial lectin LecA and the host cell glycosphingolipid globotriaosylceramide (Gb3) for the cellular uptake of P. aeruginosa into epithelial cells via the lipid zipper mechanism. To further characterize the host cell plasma membrane domain for LecA-driven attachment and invasion, we analyzed the protein and lipid composition of pulled-down membrane domains for novel interaction partners of LecA by mass spectrometry. We unraveled a predilection of LecA for binding to saturated Gb3 species in the extracellular membrane leaflet and an induction of dynamic phosphatidylinositol (3,4,5)-trisphosphate clusters at the intracellular leaflet co-localizing with sites of LecA binding. Moreover, we identified the GPI-anchored protein CD59 and flotillins, known as cargo and eponymous component of flotillin-assisted endocytosis, as LecA interaction partners. Depletion of each of these host cell proteins resulted in more than 50% of reduction in invasiveness of the P. aeruginosa strain PAO1 highlighting the importance of this LecA-induced plasma membrane domain. Our strategy to reduce the complexity of host-pathogen interactions by first identifying interaction partners of a single virulence factor and subsequently transferring these findings to the bacterium has been proven to be a successful approach in elucidating the molecular mechanisms of bacterial infections.

cell biology↗

bioRxiv2020

ZBTB18 interacts with CTBP2 and represses SREBP genes to inhibit fatty acid synthesis in glioblastoma

Enhanced fatty acid synthesis is a hallmark of tumors, including glioblastoma. SREBF1/2 regulate the expression of enzymes involved in fatty acid and cholesterol synthesis. Yet, little is known about the precise mechanism regulating SREBP gene expression in glioblastoma. Here, we show that a novel interaction between the co-activator/co-repressor CTBP and the tumor suppressor ZBTB18 regulates the expression of SREBP genes. Our study points at CTBP1/2 and LSD1 as co-activators of SREBP genes whose complex functional activity is altered by ZBTB18. ZBTB18 binding to the SREBP gene promoters is associated with reduced LSD1 demethylase activity of H3 active marks leading to increased di-methylation of lysine 4 (H3K4me2). Concomitantly, we observed increased di-methylation of lysine 9 (H3K9me2), and decrease of the active mark H3K4me3 with consequent repression of the SREBP genes. In line with our findings, lipidomic analysis shows a reduction of several phospholipid species upon ZBTB18 expression. Our results outline a new epigenetic mechanism enrolled by ZBTB18 and its cofactors to regulate fatty acid synthesis that could be targeted to treat glioblastoma patients.

cancer biology↗