Biology subjects

Kuznetsova, T.

Publications and source records attributed to Kuznetsova, T..

7 recordsLinked to original sources

bioRxiv2026

Glycometabolic, inflammatory and exocrine plasma proteins predict cancer in individuals with cardiovascular disease

Cancer development is preceded by systemic immune, metabolic and tissue perturbation. We asked whether a minimal circulating-protein signature anticipates incident cancer in patients with atheromatous cardiovascular disease (ACVD) exposed to tobacco. Discovery used a nested case-control set drawn from the longitudinal FLEMENGHO cohort (n=156; 38 incident lung cancers). Multi-omic profiling returned a two-step classifier: four proteins, smoking status, personal cancer history. Preprocessing constants, classifiers and both thresholds were fixed before transfer to PREVALUNG (n=397; 58 incident cancers, 26 of them lung). There, low O-GlcNAcase (OGA) with low interleukin-6 (IL-6) defined a very-low-risk stratum holding 1 of 58 cancers (sensitivity 98.3%, negative predictive value 98.8%); low chymotrypsin C (CTRC) with high beta microseminoprotein (MSMB) defined a high-risk stratum in which 15 of 28 participants developed cancer. No additional omic feature (metabolomic, immunophenotypic, clonal-haematopoietic or metagenomic) was retained as a reproducible improvement to the classifier under our selection framework. Discrimination was greater for cancers diagnosed more than 12 months after sampling than for near-term cancers (AUC 0.766, 95% CI 0.671-0.857, versus 0.589, 0.485-0.692), arguing against performance being driven principally by occult disease. These estimates are conditional on the cancer frequency of this population. They require prospective confirmation before any imaging schedule is changed.

cancer biology↗

bioRxiv2025

A CROP-seq screen of histone modifying enzymes reveals histone demethylase Kdm5c regulates inflammatory macrophage activation.

BackgroundMacrophages adopt activation states along a spectrum from pro- to anti-inflammatory, enabling appropriate responses to pathogens and environmental cues. Dysregulated inflammatory macrophage activation contributes to diseases including sepsis, rheumatoid arthritis, cancer, and atherosclerosis. Epigenetic processes such as DNA methylation and histone modification prime macrophages for activation, and several histone modifying enzymes (HMEs) have been implicated in this regulation. ObjectiveTo systematically identify histone modifying enzymes that regulate inflammatory macrophage activation. MethodsWe performed a CRISPR knockout screen with single-cell RNA-seq readout (CROP-seq) targeting 92 macrophage-expressed HMEs in immortalized LPS-activated mouse bone marrow-derived macrophages (BMDMs). The resulting single-cell transcriptomes were analyzed to identify significant perturbations. Kdm5c was selected for experimental validation in mouse BMDMs, and its expression pattern was compared with macrophage subsets from human atherosclerotic plaques using scRNA-seq data. ResultsThe CROP-seq screen identified Prmt6, Carm1, Kat2b, and Kdm5c as top regulators of inflammatory macrophage activation. Validation in a KO cell line revealed loss of Kdm5c suppressed inflammatory tone at baseline but led to an exaggerated transcriptional response to LPS stimulation, indicating a role for Kdm5c in balancing tonic and inducible activation. A weighted gene module derived from Kdm5c-deficient macrophages was enriched in inflammatory macrophages in human atherosclerotic plaques. ConclusionOur findings demonstrate the value of CROP-seq screening to dissect the epigenetic control of macrophage activation. We also identify Kdm5c-mediated histone demethylation as a key mechanism modulating inflammatory macrophage activation.

molecular biology↗

bioRxiv2023

Extracellular Matrix Regulates Neuronal Chloride Concentration via K+-Cl--Cotransporter 2

The neuronal intracellular chloride concentration [Cl-]i is critical for {gamma}-aminobutyric acid type A (GABAA) receptor-mediated transmission. Degradation of the extracellular matrix (ECM) is associated with raised [Cl-]I but neither the mechanisms underlying this effect nor the consequences for GABA- mediated transmission are well understood. Hitherto it has been unclear how to reconcile the effect of the ECM on [Cl-]i with the established role of cation-chloride cotransporters in setting [Cl-]I. In the present work we clarify the role of the ECM in the control of neuronal [Cl-]i. By measuring [Cl-]i in central neurons from male rats we show that the ECM affects basal [Cl-]i as well as the rate of Cl- extrusion after a high load. The mechanism is not via impermeant anions but through regulation of K+-Cl--cotransporter 2 (KCC2). ECM degradation is accompanied by an N-type Ca2+-channel- and calpain-dependent reduction in the amount of KCC2 protein, increased basal [Cl-]i, reduced Cl- extrusion capacity as well as by reduced inhibitory, or even an excitatory, effect of intense GABAA- receptor mediated trans mission. This implies a previously unrecognized pathway for the control of neuronal [Cl-]i and excitability by the ECM. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=144 SRC="FIGDIR/small/527837v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@1ee0d30org.highwire.dtl.DTLVardef@1a3eb1aorg.highwire.dtl.DTLVardef@a00b44org.highwire.dtl.DTLVardef@143b43f_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2023

Heparan sulfates regulate axonal excitability and context generalization through Ca2+/calmodulin-dependent protein kinase II

Our previous studies demonstrated that enzymatic removal of highly sulfated heparan sulfates with heparinase 1 impaired axonal excitability and reduced expression of ankyrin G at the axon initial segments in the CA1 region of the hippocampus ex vivo, impaired context discrimination in vivo, and elevated Ca2+/calmodulin-dependent protein kinase II (CaMKII) activity in vitro. Here, we show that in vivo delivery of heparinase 1 in the CA1 region of the hippocampus elevated autophosphorylation of CaMKII 24 hours after injection in mice. Patch-clamp recording in CA1 neurons revealed no significant heparinase effects on the amplitude or frequency of miniature excitatory and inhibitory postsynaptic currents, while the threshold for action potential generation was increased and fewer spikes were generated in response to current injection. Delivery of heparinase on the next day after contextual fear conditioning induced context overgeneralization 24 hours after injection. Co-administration of heparinase with the CaMKII inhibitor (autocamtide-2-related inhibitory peptide) rescued neuronal excitability and expression of ankyrin G at the axon initial segment. It also restored context discrimination, suggesting a key role of CaMKII in neuronal signaling downstream of heparan sulfate proteoglycans and highlighting a link between impaired CA1 pyramidal cell excitability and context generalization during recall of contextual memories.

neuroscience↗

bioRxiv2022

Multiphoton holographic photostimulation induces potassium-dependent spike silencing in label-free mouse cortex in vivo

Multiphoton microscopy allows measurement of network activity as well as the manipulation of cell type specific or functionally identified neuronal subpopulations with optogenetic holographic stimulation. When neurons co-express an activity reporter (e.g. calcium or voltage-sensitive indicators) and an (excitatory or inhibitory) opsin, such "all optical" interrogation approaches in vivo allows to draw causal links between function of cell-type specific microcircuits and behaviour. However, the net effects of near-infrared stimulation on network activity per se remain to be adequately investigated in vivo. Here we show that multicell holographic photostimulation with near-infrared radiation with total powers to sample used in current literature halves the spike rate of the non-illuminated neurons in label-free mouse cortex in vivo. The effect is not mediated by GABA release, but depends on NIR-dependent gating of potassium channels as it is absent when neurons are intracellularly perfused with the broad potassium channel blocker cesium ions, and are possibly mediated by heating. The phenomenon may contribute to set an upper limit to holographic photostimulation efficacy, calls for the need to control the effects of holographic stimulation protocols per se in label free preparations, and might be of relevance to interpret the therapeutical effects on infrared stimulation in psychiatry and neurology. Highlights- Holographic multi-cell, infrared illumination halves spike rates of no-target neurons - The effect happens with total powers to sample used in "all-optical" literature - Infrared-driven spike killing is GABA-independent but depends on potassium channels

neuroscience↗

bioRxiv2021

Visual stimulation with blue wavelength light drives V1 effectively eliminating stray light contamination during two-photon calcium imaging

BACKGROUNDBrain visual circuits are often studied in vivo by imaging Ca2+ indicators with green-shifted emission spectra. Polychromatic white visual stimuli have a spectrum that partially overlaps indicators emission spectra, resulting in significant contamination of calcium signals. NEW METHODTo overcome light contamination problems we choose blue visual stimuli, having a spectral composition not overlapping with Ca2+ indicators emission spectrum. To compare visual responsiveness to blue and white stimuli we used electrophysiology (visual evoked potentials-VEPs) and 3D acousto-optic two-photon(2P) population Ca2+ imaging in mouse primary visual cortex (V1). RESULTSVEPs in response to blue and white stimuli had comparable peak amplitudes and latencies. Ca2+ imaging revealed that the populations of neurons responding to blue and white stimuli were largely overlapping, that their responses had similar amplitudes, and that functional response properties such as orientation and direction selectivities were also comparable. COMPARISON WITH EXISTING METHODSMasking or shielding the microscope are often used to minimize the contamination of Ca2+ signal by white light, but they are time consuming, bulky and thus can limit experimental design, particularly in the more and more frequently used awake set-up. Blue stimuli not interfering with imaging allow to omit shielding without affecting V1 physiological responsiveness. CONCLUSIONSOur results show that the selected blue light stimuli evoke physiological responses comparable to those evoked by white stimuli in mouse V1. This will make complex designs of imaging experiments in behavioral set-ups easier, and facilitate the combination of Ca2+ imaging with electrophysiology and optogenetics. HighlightsO_LIWhite and blue light trigger VEPs with similar amplitudes and latencies in mouse V1 C_LIO_LIBlue-and white-responding neurons are two largely overlapping neuronal populations C_LIO_LIBlue and white evoke Ca2+ responses similar in magnitude and latency C_LIO_LIBlue and white evoke Ca2+ responses similar in orientation/direction selectivity C_LIO_LIBlue stimuli could be an alternative to white ones in behavior and opto-physiological tests C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=149 SRC="FIGDIR/small/433182v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@66c0a2org.highwire.dtl.DTLVardef@1f0cce9org.highwire.dtl.DTLVardef@1ce97borg.highwire.dtl.DTLVardef@24a3f1_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2019

An Inflammatory Clock Predicts Multi-morbidity, Immunosenescence and Cardiovascular Aging in Humans

While many diseases of aging have been linked to the immunological system, immune metrics with which to identify the most at-risk individuals are lacking. Here, we studied the blood immunome of 1001 individuals age 8-96 and derived an inflammatory clock of aging (iAge), which tracked with multi-morbidity and immunosenescence. In centenarians, iAge was on average, 40 years lower than their corresponding chronological age. The strongest contributor to this metric was the chemokine CXCL9, which was involved in cardiac aging, affected vascular function, and down-regulated Sirtuin-3, a longevity-associated molecule. Thus, our results identify an important link between inflammatory molecules and pathways known to govern lifespan.

immunology↗