Biology subjects

Kozhevnikova, E.

Publications and source records attributed to Kozhevnikova, E..

6 recordsLinked to original sources

bioRxiv2026

Bayesian Network Analysis Identifies PREX1 as a Master Regulator of Cytoskeletal Disruption in Inflammatory Bowel Disease

BackgroundInflammatory bowel diseases are complex multifactorial and polygenic conditions with incompletely understood etiology. Transcriptomic and metabolomic studies reveal hundreds of genes and metabolites associated with the inflammatory dowel diseases (IBD), while about 240 genetic loci are associated with these diseases. IBD are accompanied by numerous epithelial lesions including epithelial cells damage and barrier dysfunction. Recent studies suggest that cytoskeleton dysregulation underlies these aspects of IBD. We have previously shown that the disruption of cortical actin filaments and microvilli degeneration are characteristic of Muc2 mouse IBD model. MethodsWe used transmission electron microscopy to evaluate ultrastructural defects in the intestinal epithelium of IBD patients. A probabilistic graphical model (Bayesian network) was employed in order to identify the key gene network hierarchy that might define cytoskeletal architecture among other regulatory events in IBD. The Bayesian network was based on preselected key node genes from open access transcriptomic data obtained in patients with Crohns disease. ResultsElectron microscopy of IBD patients demonstrated disruption of the brush border ultrastructure, similar to the microvillar defects previously described in Muc2 colitis model mice. We highlighted a list of genes contributing to actin polymerization and bundling, of which PREX1 were further confirmed using the transcriptome data obtained from Muc2 mice. ConclusionOur study underscores the utility of Bayesian network analysis in complex cellular phenotypes that helped to identify potential target genes responsible for cortical cytoskeleton and microvilli disruption upon chronic intestinal inflammation.

bioinformatics↗

bioRxiv2026

F-actin dynamics couples sphingolipid metabolism to epithelial barrier integrity in chronic colitis

BackgroundIntestinal barrier dysfunction is a hallmark of inflammatory bowel diseases (IBD). This condition causes intoxication and immune hyperactivation. Understanding the events underlying epithelial barrier disruption during chronic inflammation is key to developing barrier-restoring therapies. Filamentous actin (F-actin) is essential for maintaining polarity and junctional integrity. However, the contribution of F-actin dynamics to IBD-associated barrier dysfunction remains unclear. ObjectiveWe aimed to examine actin cytoskeleton integrity during chronic colitis across mouse models and human patients and identify potential regulators of cytoskeleton dynamics. DesignF-actin and junctional proteins were analyzed in three models of chronic colitis (Muc2 KO, DSS-induced colitis, adoptive transfer colitis) using confocal microscopy. Claudin-3 interactors were identified by immunoprecipitation and proteomics. Intestinal organoids were used to assess the effect of F-actin disruption on barrier integrity. Metabolomic and gene expression analyses identified candidate pathways, further validated by chemical inhibition. Biopsies from patients with ulcerative colitis (UC) were examined using transmission electron microscopy and confocal microscopy. ResultsDisrupted actin dynamics emerged as a critical driver of epithelial barrier dysfunction in chronic colitis. An imbalance between polymeric and monomeric actin impaired barrier integrity in vivo and in 3D organoids. Immunoprecipitation identified actin and associated factors as the primary interactors of claudin-3 with reduced interaction during inflammation. Ceramide metabolism was revealed as a potential regulator of F-actin and intestinal barrier. In UC patients, we confirmed concurrent disruption of junctions and F-actin. ConclusionsF-actin dysregulation contributes to barrier dysfunction in IBD and targeting its modulators, including ceramide biosynthesis, represents a novel therapeutic strategy. WHAT IS ALREADY KNOWN ON THIS TOPICO_LIEpithelial damage and increased paracellular permeability are key characteristics of inflammatory bowel diseases. C_LIO_LIParacellular permeability is partially attributed to the downregulation of junction proteins but this mechanism does not explain all clinical observations. C_LIO_LIIn the Muc2 KO mouse model of chronic colitis, F-actin organization and membrane localization of tight junction protein claudin-3 are disrupted, although protein expression levels remain unchanged. C_LI WHAT THIS STUDY ADDSO_LIF-actin dynamics is impaired in the intestinal epithelium across three different mouse models of chronic colitis and IBD patients. C_LIO_LIDisruption of F-actin dynamics leads to impaired membrane localization of tight and adherens junction proteins and increased intestinal epithelial permeability in vivo and in colonic organoids. C_LIO_LIInhibition of ceramide biosynthesis rescues F-actin polymerization and intestinal barrier integrity in mouse chronic colitis models. C_LI HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICYO_LITargeting F-actin dynamics is a promising approach to improve gut epithelial integrity. C_LIO_LI"Ceramide-F-actin-junction" axis is proposed as one of the mechanisms behind epithelial barrier disruption in colitis. Therapeutic targeting of this axis represents a promising path for restoring gut integrity. C_LI

cell biology↗

bioRxiv2023

Investigating social communication in mice: a Two-intruders test approach

Understanding the complex dynamics of social communication behaviors, such as exploration, communication, courtship, mating, and aggression in animal models is crucial to reveal key neural and hormonal mechanisms underlying these behaviors. The Two-intruders test is designed to investigate residents behavior toward a male and female intruders. During this test imitating natural conditions, several aspects of social interaction were investigated: exploration, courtship, mating, and aggressive behavior. As mating and aggression involve overlapping neural circuits, the behavioral setup testing both behaviors is best at reflecting their competitive nature. Our findings demonstrate that male mice exhibit strong preference to communicate with a female intruder, which correlates with baseline testosterone levels of test males. Relevant female preference in the Two-intruder test was also found in BALB/c males. Behavioral breakdown revealed the anogenital sniffing as a key behavioral feature that discriminates test male behavior toward intruders of different genders. At the same time, female preference was accompanied by neuronal activation in the ventromedial hypothalamus. We demonstrate that odor recognition underlies preference toward females in male residents, as experimental anosmia reduced communication with a female intruder. However, there was no correlation between female animal preference in the contact Two-intruder test and smell preference in the social odor preference test. We assume the Two-intruders test setup to be a useful tool to study the neurological basis of social communication in animal models. Combined with odor preference tests, this experimental paradigm can help to decipher neural circuits involved in social deficiency phenotypes in animal models of human diseases. Significance StatementThe Two-intruders test proves to be a highly reproducible and robust approach to assess social communication in mice. We demonstrate that the results obtained in this experimental setting replicate in different mouse groups and strains. This test is indispensable in studies assessing the competitive nature of male- and female-driven behaviors and the underlying neural mechanisms. Residents social interactions in the described here set up reflects odor processing and circulating testosterone - the key physiological drivers of animal communication with conspecifics. While easy to perform, this test provides a broad spectrum of behavioral patterns to study in the models of complex neurological diseases. Largely overseen in the literature as compared to the resident-intruder setup, the Two-intruders test can provide superior performance when used to understand the neural mechanisms of mating, aggression and social communication.

neuroscience↗

bioRxiv2023

Mouse Genome Editing from Scratch

Mouse genome modification requires costly equipment and highly skilled personnel to manipulate zygotes. A number of zygote electroporation techniques were reported to be highly efficient in gene delivery. One of these methods called i-GONAD (improved Genome-editing via Oviductal Nucleic Acids Delivery) describes electroporation-based gene transfer to zygotes in utero. Here we adopted this technology for mouse genome-editing from scratch minimizing the cost of equipment, operator skill and animal use. We chose the CRISPR/Cas9 system as a genome editing tool and i-GONAD as a gene delivery method to produce IL10 gene knockout in C57BL/6 mice. Four animals out of 13 delivered pups (30.8%) were genetically compromised at IL10 gene locus suggesting the feasibility of the approach. This report provides one of the possible technical settings for those who aim at establishing in-house mouse transgenesis pipeline at minimal cost from scratch. For citationPopova J.V., Bets V.D., Omelina E.S., Boldyreva L.V., Kozhevnikova E.N. Mouse Genome Editing from Scratch. Journal of Experimental Biology. Year; issue (number): page. DOI

bioengineering↗

bioRxiv2022

Colitis-associated intestinal microbiota regulates brain glycine and host behavior in mice.

Inflammatory bowel diseases (IBD) are chronic and relapsing inflammatory disorders of the gastrointestinal tract with complex etiology and no strategies for complete cure. IBD are often complicated by mental disorders like anxiety and depression, indicating substantial shifts in the gut-brain axis. However, the mechanisms connecting IBD to mental diseases are still under debate. Here we use Muc2 mutant mouse model of chronic colitis to uncouple the effects of the intestinal microbiota on host behavior from chronic inflammation in the gut. Muc2 mutant male mice exhibit high exploratory activity, reduced anxiety-related behaviors, impaired sensorimotor gating, and altered social preference towards males and females. Microbial transfer to wild-type mice via littermate co-housing shows that colitis-associated microbiota rather than inflammation per se defines behavioral features in Muc2 colitis model. Metagenomic profiling and combination of antibiotic treatments revealed that bacterial species Akkermansia muciniphila is associated with the behavioral phenotype in mutants, and that its intestinal abundance correlates with social preference towards males. Metabolomic analysis together with pharmacological inhibition of Gly and NMDA receptors helped us to determine that brain glycine is responsible for the behavioral phenotype in Muc2 mice. Blood and brain metabolic profiles suggest that microbiota-dependent changes in choline metabolism might be involved in regulation of central glycine neurotransmission. Taken together, our data demonstrates that colitis-associated microbiota controls anxiety, sensorimotor gating and social behavior via metabolic regulation of the brain glycinergic system, providing new venues to combat neurological complications of IBD.

animal behavior and cognition↗

bioRxiv2020

Evaluating aerosol and splatter following dental procedures

BackgroundDental procedures often produce aerosol and splatter which are potentially high risk for spreading pathogens such as SARS-CoV-2. The existing literature is limited. Objective(s)To develop a robust, reliable and valid methodology to evaluate distribution and persistence of dental aerosol and splatter, including the evaluation of clinical procedures. MethodsFluorescein was introduced into the irrigation reservoirs of a high-speed air-turbine, ultrasonic scaler and 3-in-1 spray and procedures performed on a mannequin in triplicate. Filter papers were placed in the immediate environment. The impact of dental suction and assistant presence were also evaluated. Samples were analysed using photographic image analysis, and spectrofluorometric analysis. Descriptive statistics were calculated and Pearsons correlation for comparison of analytic methods. ResultsAll procedures were aerosol and splatter generating. Contamination was highest closest to the source, remaining high to 1-1.5 m. Contamination was detectable at the maximum distance measured (4 m) for high-speed air-turbine with maximum relative fluorescence units (RFU) being: 46,091 at 0.5 m, 3,541 at 1.0 m, and 1,695 at 4 m. There was uneven spatial distribution with highest levels of contamination opposite the operator. Very low levels of contamination ([≤]0.1% of original) were detected at 30 and 60 minutes post procedure. Suction reduced contamination by 67-75% at 0.5-1.5 m. Mannequin and operator were heavily contaminated. The two analytic methods showed good correlation (r=0.930, n=244, p<0.001). ConclusionDental procedures have potential to deposit aerosol and splatter at some distance from the source, being effectively cleared by 30 minutes in our setting.

microbiology↗