Biology subjects

Hecker, M.

Publications and source records attributed to Hecker, M..

11 recordsLinked to original sources

bioRxiv2026

miR-378a and NPNT coordinate autophagy regulation in podocytes through mTOR and MAPK signaling

Autophagy is a critical homeostatic mechanism in podocytes, maintaining cellular integrity under stress and proteostatic challenges. Dysregulation of autophagy has been implicated in different glomerular diseases such as diabetes and membranous glomerulonephropathy (MGN), yet the underlying molecular drivers remain incompletely understood. We identified microRNA-378a (miR-378a), previously found upregulated in MGN, as a functional enhancer of autophagic flux in human podocytes and tubular epithelial cells. While miR-378a did not directly alter transcription of canonical autophagy genes (ATG2A, ATG5, ATG7, ATG12), it increased autophagic flux through suppression of mTOR phosphorylation at Ser2448. Given that NPNT is a miR-378a target and a key glomerular basement membrane component, we investigated its role in autophagy regulation. NPNT knockdown reduced ATG2A, ATG7, and BCN1 expression, but paradoxically increased autophagic flux, independent of mTOR, accompanied by enhanced ERK1/2 phosphorylation. These findings reveal a dual-layered regulatory network in which miR-378a promotes autophagy via mTOR inhibition, whereas NPNT modulates autophagy probably through MAPK-dependent signaling. Our results highlight the complex interplay between miRs, extracellular matrix components, and intracellular signaling pathways in podocyte autophagy. Dysregulation of these pathways in kidney disease may reflect both adaptive and maladaptive responses, providing mechanistic insights and potential therapeutic targets to preserve glomerular filtration barrier integrity in immune-mediated kidney disease.

cell biology↗

bioRxiv2026

Mitochondrial COX4I2 drives pericyte-dependent inflammation and emphysema

Chronic obstructive pulmonary disease (COPD) is characterized by neutrophilic inflammation, emphysema, and mild pulmonary hypertension (PH). Oxidative/nitrosative stress are key drivers, but specific mitochondrial mechanisms remain unclear. We show increased expression of the regulatory mitochondrial cytochrome c oxidase subunit 4 isoform 2 (COX4I2) in an early murine model and human COPD. After 8 months of cigarette smoke exposure, Cox4i2-/- mice were completely protected from emphysema but not from PH, associated with reduced nitrosative stress, inflammation, and apoptosis. Using a novel Cox4i2 reporter mouse and in situ hybridization of human lungs, COX4I2 was detected in precapillary ACTA2+ cells and capillary pericytes. COX4I2 promotes mitochondrial reactive oxygen species (mtROS) production in these cells, thereby enhancing neutrophil migration and alveolar type II cell apoptosis, and modulates angiogenesis. In contrast to Cox4i2-/-, mitochondria-targeted antioxidant MitoQ reversed emphysema and PH, suggesting pericyte-specific regulation of COPD pathologies and mtROS inhibition as a therapeutic approach in COPD. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=124 SRC="FIGDIR/small/703513v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@83bca4org.highwire.dtl.DTLVardef@d5ebaborg.highwire.dtl.DTLVardef@632d1borg.highwire.dtl.DTLVardef@1267a13_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2024

Sub-chronic and acute toxicity of 6PPD-quinone to early-life stage rainbow trout (Oncorhynchus mykiss)

N-(1,3-Dimethylbutyl)-N-phenyl-p-phenylenediamine-quinone (6PPD-Q) is a derivative of rubber tires which leaches into surface waters when tire particles are swept into roadway runoff. 6PPD-Q has been identified as a potential cause of urban runoff mortality syndrome in coho salmon, and subsequent research has determined a wide species variation in toxicity among fishes. While adult rainbow trout are known to be sensitive, there is limited research on their early-life stages. Given that early-life stages of fish are often more sensitive than adults, the aim of these studies was to assess the acute and sub-chronic toxicity of 6PPD-Q in early-life stage rainbow trout. Rainbow trout alevins were exposed from hatch until 28 days post-hatch (dph) to time-weighted average 6PPD-Q concentrations ranging from 0.06-2.35 g/L. From these studies, a 28-day median lethal dose (LC50) of 0.56 g/L was derived. Morphological deformities were observed during the exposure period, including pooling of blood in the caudal fin. A follow-up acute study with exogenously feeding rainbow trout fry revealed a 96-hour LC50 of 0.47 g/L. These studies indicate that early-life stage rainbow trout are more sensitive than previously studied sub-adults, with exogenously feeding fry being the most sensitive life stage studied so far, and that sub-chronic exposure to 6PPD-Q can result in developmental abnormalities. This research highlights the importance of utilizing early-life stage studies to determine the most sensitive benchmark concentrations and their value in determining sub-lethal effects.

pharmacology and toxicology↗

bioRxiv2024

Xenometabolome of Early-Life Stage Salmonids Exposed to 6PPD-Quinone

N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) is a ubiquitous transformation product (TP) derived from the rubber tire antioxidant N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and is acutely toxic to certain species of Salmonidae. Not all salmonids are sensitive to acute lethality caused by 6PPD-Q, with 6PPD-Q potency varying by several orders of magnitude among teleosts. The main driver(s) of species sensitivity differences is (are) a pressing question, with one area of interest examining whether differences in teleosts ability to biotransform and detoxify 6PPD-Q could be a key factor. This study utilized liquid-chromatography high-resolution mass spectrometry (LC-HRMS) to assess biotransformation and metabolome-wide effects of 6PPD-Q on early-life stage salmonids, including two sensitive species, rainbow trout (Oncorhynchus mykiss) and lake trout (Salvelinus namaycush), and one tolerant species, brown trout (Salmo trutta). Three phase I TPs and seven phase II TPs were detected, with differences in peak areas revealing that brown trout had the greatest ability to detoxify 6PPD-Q. Monohydroxylated TPs were verified using co-developed analytical standards that will be of use for future biomonitoring and exposure assessment. Several endogenous metabolites were found to be dysregulated in rainbow and lake trout, indicative of mitochondrial dysfunction, altered metabolism, and disrupted membrane permeability. Results of this study indicate a difference in the biotransformation capability of 6PPD-Q among Salmonidae fish species and subsequent unique metabolome responses. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=62 SRC="FIGDIR/small/598661v2_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@1931a42org.highwire.dtl.DTLVardef@a0f446org.highwire.dtl.DTLVardef@10540d0org.highwire.dtl.DTLVardef@1e21b49_HPS_FORMAT_FIGEXP M_FIG C_FIG SynopsisInter-species salmonid differences in the biotransformation capability of 6PPD-Q leads to sensitivity variability and subsequent unique metabolome responses.

pharmacology and toxicology↗

bioRxiv2024

Acute and sub-chronic toxicity of 6PPD-quinone to early-life stage lake trout (Salvelinus namaycush)

N-(1,3-Dimethylbutyl)-N-phenyl-p-phenylenediamine-quinone (6PPD-q) is a rubber-tire derivative which leaches into surface waters from roadway runoff, from tire particles and has been identified as a possible driver of urban runoff mortality syndrome in coho salmon. Sensitivity to this toxicant is highly variable across fish species and life stages. With environmental concentrations meeting or exceeding toxicity thresholds in sensitive fishes, the potential for ecologically relevant effects is significant. There is currently no data regarding the sensitivity of lake trout (Salvelinus namaycush) to 6PPD-q. As early-life stages of fishes are typically more sensitive than adults, the goal of these studies was to evaluate the acute and sub-chronic toxicity of 6PPD-q to early-life stage lake trout. Alevins exposed from hatch until 45 days post hatch (dph) to time-weighted average 6PPD-q concentrations ranging from 0.22-13.5 g/L exhibited a 45-day median lethal dose (LC50) of 0.39 g/L. Deformities throughout growth were observed, with a unique pooling of blood observed in the caudal fin and eye. A subsequent acute study with exogenously feeding lake trout fry determined a 96-hr LC50 of 0.50 g/L. From these studies we can conclude that lake trout alevins and exogenously feeding fry are sensitive to 6PPD-q, which underscores the relevance of this chemical to inland freshwater ecosystems.

physiology↗

bioRxiv2024

Underlying molecular effects to behavioral consequences present line of evidence for zebrafish eye development and function alteration by crude oil exposure.

Crude oil can affect the normal eye development and swimming behavior of fish embryos. In this study 0-4 hours post fertilization (hpf) zebrafish (Danio rerio) embryos were exposed to low, sublethal concentrations of water-accommodated fractions (WAF) of a naphthenic North Sea crude oil alone and in combination with a third-generation chemical dispersant. Effects on eye development and function at the transcript, histological, morphological, and behavioral level were assessed relative to untreated control specimen at 119 hpf. Exposed embryos swam significantly less during the dark phases of the light/dark transition test. Eye size of zebrafish embryos was significantly smaller in groups exposed to crude oil WAFs. Zebrafish retina histology revealed that, among other structural alterations, the outer nuclear layer, containing photoreceptor cells relevant for normal visual functioning, was significantly thinner in exposed embryos. Transcriptome analysis revealed that several genes involved in eye development and function (opsins and crystallins) were dysregulated upon oil exposure. The molecular effects on gene expression and eye histology results form a novel line of evidence that explains the observed effects of crude oil on the swimming activity of exposed fish embryos. The present study is in line with recent findings highlighting the importance of ocular toxicity in developing embryos exposed to petroleum samples at environmentally relevant and non-lethal concentrations without visible malformations. The study suggests that oculotoxicity should be considered as a major toxicity pathway alongside to the well-established cardiotoxicity.

developmental biology↗

bioRxiv2023

NFAT5-dependent transcriptional stress control of endothelial cells prevents maladaptive remodeling of pulmonary arterioles in the hypoxic lung

AimsChronic hypoxia causes detrimental structural alterations in the lung, which are partially dependent on stress responses of the endothelium. In this context, we revealed that hypoxia-exposed murine lung endothelial cells (MLEC) activate nuclear factor of activated T-cells 5 (NFAT5) - a transcription factor that adjusts the cellular transcriptome to cope with multiple environmental stressors. Here, we studied the functional relevance of NFAT5 for the control of hypoxia-induced transcription in MLEC. Methods and ResultsTargeted ablation of Nfat5 in endothelial cells did not evoke phenotypic abnormalities in normoxia-exposed mice. However, MLEC in Nfat5-deficient mice up-regulated energy- and protein-metabolism-associated gene expression under normobaric hypoxia (10% O2) for seven days as evidenced by microarray- and scRNA-seq-based analyses. Moreover, loss of NFAT5 boosted the expression and release of platelet-derived growth factor B (Pdgfb) - a HIF1-regulated driver of vascular smooth muscle cell (VSMC) growth - in capillary MLEC of hypoxia-exposed mice, which was accompanied by exaggerated coverage of distal pulmonary arterioles by VSMC, increased pulmonary vascular resistance and impaired right ventricular functions. In vitro, knockout of Nfat5 in cultured MLEC stimulated Pdgfb expression and release after exposure to hypoxia and amplified binding of HIF1 in the Pdgfb promoter region. ConclusionCollectively, our study identifies NFAT5 as a protective transcription factor required to rapidly adjust the transcriptome of MLEC to hypoxia. Specifically, NFAT5 restricts HIF1-mediated Pdgfb expression and consequently limits muscularization and resistance of pulmonary arterioles. HighlightsO_LIHypoxia stimulates the transcriptional activity of NFAT5 in MLEC. C_LIO_LILoss of NFAT5 in hypoxia-exposed MLEC results in EC subtype-specific maladaption of growth factor-, energy- and protein-metabolism-associated gene expression. C_LIO_LISpecifically, NFAT5-deficient capillary lung EC unleash HIF1-regulated Pdgfb expression and release, which results in excessive coverage of pulmonary arterioles by VSMC. C_LIO_LINFAT5-dependent control of early stress responses of capillary MLEC is required to limit the increase in pulmonary vascular resistance and impairment of right ventricular functions. C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=166 SRC="FIGDIR/small/563022v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@c9be61org.highwire.dtl.DTLVardef@f1d7cforg.highwire.dtl.DTLVardef@18f795forg.highwire.dtl.DTLVardef@695601_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2023

Toxicokinetic Characterization of the Inter-Species Differences in 6PPD-Quinone Toxicity Across Seven Fish Species: Metabolite Identification and Semi-Quantification

N-(1,3-Dimethylbutyl)-N-Phenyl-P-Phenylenediamine-Quinone (6PPD-Q) is a recently identified contaminant that originates from the oxidation of the tire anti-degradant 6PPD. 6PPD-Q is acutely toxic to select salmonids at environmentally relevant concentrations, while other fish species display tolerance to concentrations surpassing those measured in the environment. The reasons for these marked differences in sensitivity are presently unknown. The objective of this research was to explore potential toxicokinetic drivers of species sensitivity by characterizing biliary metabolites of 6PPD-Q in sensitive and tolerant fishes. For the first time, we identified an O-glucuronide metabolite of 6PPD-Q using high-resolution mass spectrometry. The semi-quantified levels of this metabolite in tolerant species or life stages, including white sturgeon (Acipenser transmontanus), chinook salmon (Oncorhynchus tshawytscha), westslope cutthroat trout (Oncorhynchus clarkia lewisi) and non-fry life stages of Atlantic salmon (Salmo salar), were greater than those in sensitive species, including coho salmon (Oncorhynchus kisutch), brook trout (Salvelinus fontinalis), and rainbow trout (Oncorhynchus mykiss), suggesting that tolerant species might more effectively detoxify 6PPD-Q. Thus, we hypothesize that differences in species sensitivity are a result of differences in basal expression of biotransformation enzyme across various fish species. Moreover, the semi-quantification of 6PPD-Q metabolites in bile extracted from wild-caught fish might be a useful biomarker of exposure to 6PPD-Q, thereby being invaluable to environmental monitoring and risk assessment.

pharmacology and toxicology↗

bioRxiv2022

Pan-cancer proteomic map of 949 human cell lines reveals principles of cancer vulnerabilities

The proteome provides unique insights into biology and disease beyond the genome and transcriptome. Lack of large proteomic datasets has restricted identification of new cancer biomarkers. Here, proteomes of 949 cancer cell lines across 28 tissue types were analyzed by mass spectrometry. Deploying a clinically-relevant workflow to quantify 8,498 proteins, these data capture evidence of cell type and post-transcriptional modifications. Integrating multi-omics, drug response and CRISPR-Cas9 gene essentiality screens with a deep learning-based pipeline revealed thousands of protein-specific biomarkers of cancer vulnerabilities. Proteomic data had greater power to predict drug response than the equivalent portion of the transcriptome. Further, random downsampling to only 1,500 proteins had limited impact on predictive power, consistent with protein networks being highly connected and co-regulated. This pan-cancer proteomic map (ProCan-DepMapSanger), available at https://cellmodelpassports.sanger.ac.uk, is a comprehensive resource revealing principles of protein regulation with important implications for future clinical studies.

systems biology↗

bioRxiv2022

Resource requirements for ecotoxicity testing: A comparison of traditional and new approach methods

Toxicity testing is under transformation as it aims to harness the potential of New Approach Methods (NAMs) as alternative test methods that may be less resource intensive (i.e., fewer animals, cheaper costs, quicker assays) than traditional approaches while also providing more data and information. While many stakeholders are of the opinion that this unfolding transformation holds significant promise as a more efficient and ethical way forward, few studies have compared the resources required for NAMs versus those needed for traditional animal-based toxicity tests, particularly in the field of ecotoxicology. The objective was to compare resources needed for traditional animal-based ecotoxicity tests versus alternative tests using emergent NAMs. From a bibliometric review, we estimate that traditional tests for a single chemical cost $118,000 USD, require 135 animals, and take 8 weeks. In comparison, alternative tests cost $2,600, require 20 animals (or none), and take up to 4 weeks to test 16 (to potentially hundreds of) chemicals. Based on our analysis we conclude that NAMs in ecotoxicology can be more advantageous than traditional methods in terms of resources required (i.e., monetary costs, number of animals needed, and testing times). We note, however, that the evidence underpinning these conclusions is relatively sparse. Moving forward, groups developing and applying NAMs should provide more detailed accounts of the resources required. In addition, there is also a need for carefully designed case studies that demonstrate the domain of applicability of NAMs (and make comparisons to traditional tests) to ultimately build confidence among the user community.

pharmacology and toxicology↗

bioRxiv2020

V. longisporum elicits media-dependent secretome responses with a further capacity to distinguish between plant-related environments

Verticillia cause a vascular wilt disease affecting a broad range of economically valuable crops. The fungus enters its host plants through the roots and colonizes the vascular system. It requires extracellular proteins for a successful plant colonization. The exoproteome of the allodiploid Verticillium longisporum was analyzed upon cultivation in different media. Secreted fungal proteins were identified by label free LC-MS/MS screening. V. longisporum induced two main secretion patterns. One response pattern was elicited in various non-plant related environments. The second pattern includes the exoprotein responses to the plant-related media, pectin-rich simulated xylem medium and pure xylem sap, which exhibited similar but additional distinct features. These exoproteomes include a shared core set of 223 secreted and similarly enriched fungal proteins. The pectin-rich medium significantly induced the secretion of 144 proteins including a number of pectin degrading enzymes, whereas xylem sap triggered a smaller but unique fungal exoproteome pattern with 32 enriched proteins. The latter pattern included proteins with domains of known effectors, metallopeptidases and carbohydrate-active enzymes. The most abundant and uniquely enriched proteins of these different groups are the necrosis and ethylene inducing-like proteins Nlp2 and Nlp3, the cerato-platanin proteins Cp1 and Cp2, the metallopeptidases Mep1 and Mep2 and the CAZys Gla1, Amy1 and Cbd1. Deletion of the majority of the corresponding genes caused no phenotypic changes during ex planta growth or invasion and colonization of tomato plants. However, we discovered that the NLP2 and NLP3 deletion strains were compromised in plant infections. Overall, our exoproteome approach revealed that the fungus induces specific secretion responses in different environments. The fungus has a general response to non-plant related media whereas it is able to fine-tune its exoproteome in the presence of plant material. Importantly, the xylem sap-specific exoproteome pinpointed Nlp2 and Nlp3 as single effectors required for successful V. dahliae colonization. Author SummaryVerticillium spp. infect hundreds of different plants world-wide leading to enormous economic losses. Verticillium wilt is a disease of the vasculature. The fungus colonizes the xylem of its host plant where it exploits the vascular system to colonize the whole plant. Therefore, the fungus spends part of its lifetime in this nutrient-low and imbalanced environment where it is inaccessible for disease control treatments. This lifestyle as well requires the fungus to react to plant defense responses by secreting specific effector molecules to establish a successful infection. We addressed the differences in media-dependent secretion responses of Verticillium longisporum. We identified a broad response pattern induced by several media, and a similar response (but with some distinct differences) for the plant-related environments: the pectin-rich medium SXM and xylem sap from the host rapeseed. Importantly, we show that the necrosis and ethylene inducing-like proteins Nlp2 and Nlp3 are xylem sap-specific proteins that are required for full V. dahliae pathogenicity on tomato. These factors play a role during the colonization phase and represent potential targets for new control strategies for Verticillium wilt.

genetics↗