Biology subjects

Nagy, P.

Publications and source records attributed to Nagy, P..

7 recordsLinked to original sources

bioRxiv2025

Soluble, but not precursor EGF induces intracrine signaling of the EGFR

EGFR is a transmembrane receptor tyrosine kinase regulating growth and survival in epithelial tissues. Its ligand, the epidermal growth factor (EGF), is produced as a membrane-anchored precursor (preEGF) that is proteolytically cleaved to release soluble EGF (sEGF). EGFR overexpression can convert it from a physiological regulator into an oncogenic driver. Therapeutic strategies targeting EGFR include monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs). Although mAbs such as cetuximab initially block EGFR activity, tumors often develop resistance. Recent findings indicate that sEGF can activate EGFR within intracellular vesicles, promoting intracrine signaling that sustains proliferation despite extracellular inhibition. Here, we investigated the mechanism of intracrine EGFR signaling in the Golgi apparatus using confocal microscopy, FRET and fluorescence correlation spectroscopy. sEGF, but not preEGF, bound and induced EGFR dimerization and phosphorylation. Erlotinib, a membrane permeable TKI, effectively blocked phosphorylation, whereas extracellular cetuximab did not. These findings imply sEGF-induced intracrine EGFR signaling in the Golgi. Our results may shed light on a potential resistance mechanism to antibody treatment.

biophysics↗

bioRxiv2024

Temporal expectations modulate coupling between frontal and sensory brain areas

Temporal prediction enhances perceptual processing by aligning neural excitability with expected sensory events. While local oscillatory mechanisms are known to support timing, less is understood about how large-scale functional brain networks dynamically coordinate predictive processes. In particular, it remains unclear how functional connectivity (FC)--the integration of information into network hubs--differs during expectation formation (post-cue) versus outcome evaluation (post-target), and how this varies across levels of predictability. To investigate this, we recorded electroencephalogram (EEG) while participants performed a cued auditory target-detection task with varying temporal predictability (80% and 50%). Event-related potential (ERP) results revealed that implicit temporal predictability primarily modulated later evaluative processes (P3b, frontal negativity), rather than early sensory components, consistent with context updating under uncertainty. FC was analyzed using a data-driven approach based on Normalized Directed Transfer Entropy (NDTE) applied to EEG difference waveforms between high- and low-predictability conditions. Connectivity was examined separately for the post-cue and post-target periods to distinguish prediction and evaluation phases. Behaviorally, higher temporal predictability facilitated faster reaction times. Connectivity analyses revealed largely overlapping but somewhat distinct network dynamics for prediction and evaluation phases of the signal processing.

neuroscience↗

bioRxiv2024

Interpersonal Synchronization in Mother-Child Dyads: Neural and Motor Coupling as a Mechanism for Motor Learning and Development in Preschoolers

Interpersonal movement synchrony (IMS) and brain-to-brain coupling play a crucial role in social behavior across species. In humans, IMS is often studied in structured tasks that require specific body movements, while spontaneous, unstructured movements have received less attention. In this study, we investigated both structured and spontaneous motor coordination in mother-child dyads. We recorded upper-body kinematics and dual-EEG from mothers and their preschool children during motor tasks and spontaneous face-to-face interactions. Our findings show that mother-child dyads synchronize their movements and neural activity, particularly in gamma band oscillations. This motor and neural synchrony evolves across task repetitions, with a strong correlation between motor and neural measures. Further, we observed that only motor synchronization was significantly related to the childs motor development stage, as assessed by the Movement Assessment Battery for Children. These results suggest that gamma band brain-to-brain coupling reflects joint motor coordination and mutual adaptation shaped by structured tasks and spontaneous interpersonal interactions.

neuroscience↗

bioRxiv2024

Sulfite oxidase deficiency causes persulfidation loss and H2S release

Sulfite oxidase (SOX) deficiency is a rare inborn error of cysteine metabolism resulting in severe neurological damage. In patients, sulfite accumulates to toxic levels causing a raise in downstream products S-sulfocysteine (SSC), mediating excitotoxicity, and thiosulfate, a catabolic intermediate/product of H2S metabolism. Here, we report a full-body knock-out mouse model for SOX deficiency (SOXD) with a severely impaired phenotype. Amongst the urinary biomarkers, thiosulfate showed a 45-fold accumulation in SOXD mice representing the major excreted S-metabolite. Consistently, we found increased plasma H2S, which was derived from sulfite-induced release from persulfides as demonstrated in vitro and in vivo. Mass spectrometric analysis of total protein persulfidome identified a major loss of persulfidation in 20% of the proteome affecting enzymes in amino acids and fatty acid metabolism. Urinary amino acid profiles indicate metabolic rewiring suggesting partial reversal of the TCA cycle thus identifying a novel contribution of H2S metabolism and persulfidation in SOXD.

biochemistry↗

bioRxiv2023

The transcriptional response in mosquitoes distinguishes between fungi and bacteria but not Gram types

Mosquitoes are prolific vectors of human pathogens; a clear and accurate understanding of the organization of their antimicrobial defenses is crucial for informing the development of transmission control strategies. The canonical infection response in insects, as described in the insect model Drosophila melanogaster, is pathogen type-dependent, with distinct stereotypical responses to Gram-negative bacteria and Gram-positive bacteria/fungi mediated by the activation of the Imd and Toll pathways, respectively. To determine whether this pathogen-specific discrimination is shared by mosquitoes, we used RNAseq to capture the genome-wide transcriptional response of Aedes aegypti and Anopheles gambiae (s.l.) to systemic infection with Gram-negative bacteria, Gram-positive bacteria, yeasts, and filamentous fungi, as well as challenge with heat-killed Gram-negative, Gram-positive, and fungal pathogens. From the resulting data, we found that Ae. aegypti and An. gambiae both mount a core response to all categories of infection, and this response is highly conserved between the two species with respect to both function and orthology. When we compared the transcriptomes of mosquitoes infected with different types of bacteria, we observed that the intensity of the transcriptional response was correlated with both the virulence and growth rate of the infecting pathogen. Exhaustive comparisons of the transcriptomes of Gram-negative-challenged versus Gram-positive-challenged mosquitoes yielded no difference in either species. In Ae. aegypti, however, we identified transcriptional signatures specific to bacterial infection and to fungal infection. The bacterial infection response was dominated by the expression of defensins and cecropins, while the fungal infection response included the disproportionate upregulation of an uncharacterized family of glycine-rich proteins. These signatures were also observed in Ae. aegypti challenged with heat-killed bacteria and fungi, indicating that this species can discriminate between molecular patterns that are specific to bacteria and to fungi.

immunology↗

bioRxiv2021

A transcriptomic atlas of Aedes aegypti reveals detailed functional organization of major body parts and gut regional specializations in sugar-fed and blood-fed adult females

Mosquito vectors transmit numerous pathogens, but large gaps remain in our understanding of their physiology. To facilitate future explorations of mosquito biology, with specific attention to the major vector Aedes aegypti, we have created Aegypti-Atlas (http://aegyptiatlas.buchonlab.com/), an online resource hosting RNAseq profiles of Ae. Aegypti body parts (head, thorax, abdomen, gut, Malpighian tubules, and ovaries), gut regions (crop, proventriculus, anterior and posterior midgut, and hindgut), and a time course of blood meal digestion in the gut. Using Aegypti-Atlas, we provide new insights into the regionalization of gut function, blood feeding response, and immune defenses. We find that the anterior and posterior regions of the mosquito midgut possess clearly delineated digestive specializations which are preserved in the blood-fed state. Blood feeding initiates the sequential transcriptional induction and repression/depletion of multiple cohorts of peptidases throughout blood meal digestion. With respect to defense, immune signaling components, but not recognition or effector molecules, show enrichment in ovaries. Basal expression of antimicrobial peptides is dominated by two genes, holotricin and gambicin, that are expressed in the carcass and the digestive tissues, respectively, in a near mutually exclusive manner. In the midgut, gambicin and other immune effector genes are almost exclusively expressed in the anterior regions, while the posterior midgut exhibits the hallmarks of immune tolerance. Finally, in a cross-species comparison between the midguts of Ae. aegypti and Anopheles gambiae, we observe that regional digestive and immune specializations are closely conserved, indicating that our data may yield inferences that are broadly relevant to multiple mosquito vector species. We further demonstrate that the expression of orthologous genes is highly correlated, with the exception of a species signature comprising a small number of highly/disparately expressed genes. With this work, we show the potential of Aegypti-Atlas to unlock a more complete understanding of mosquito biology.

physiology↗

bioRxiv2020

Statin-boosted cellular uptake of penetratin due to reduced membrane dipole potential

Since cell penetrating peptides are promising tools for delivery of cargo into cells, factors limiting or facilitating their cellular uptake are intensely studied. Using labeling with pH-insensitive and pH-sensitive dyes we report that escape of penetratin from acidic endo-lysosomal compartments is retarded compared to its cellular uptake. The membrane dipole potential, known to alter transmembrane transport of charged molecules, is shown to be negatively correlated with the concentration of penetratin in the cytoplasmic compartment. Treatment of cells with therapeutically relevant concentrations of atorvastatin, an inhibitor of HMG-CoA reductase and cholesterol synthesis, significantly increased the release of penetratin from acidic endocytic compartments in two different cell types. This effect of atorvastatin correlated with its ability to decrease the membrane dipole potential. These results highlight the importance of the dipole potential in regulating cellular uptake of cell penetrating peptides and suggest a clinically relevant way of boosting this process.

cell biology↗