Biology subjects

Vesely, C.

Publications and source records attributed to Vesely, C..

3 recordsLinked to original sources

bioRxiv2025

Edited Filamin A in myeloid cells reduces intestinal inflammation and protects from colitis

Patho-mechanistic origins and disease dynamics of ulcerative colitis are still poorly understood. The actin-crosslinker Filamin A (FLNA) impacts cellular responses through interaction with cytosolic proteins. FLNA exists in two forms that differ only in one amino acid: genome-encoded FLNAQ and FLNAR - generated by post-transcriptional A-to-I editing. FLNA is edited in fibroblasts, smooth muscle- and endothelial cells in the colon. We identified the FLNA editing status as a key determinant of colitis severity. FLNA editing was highest in healthy colons and reduced during acute murine and human colitis. Mice that exclusively express edited FLNAR and do not downregulate editing upon challenge were highly resistant to DSS-induced colitis, whereas fully unedited FLNAQ animals developed severe inflammation. While the genetic induction of FLNA editing influenced transcriptional states of structural cells and the microbiome composition, we found that FLNAR exerts protection specifically via its influence on myeloid cells, which are not edited under physiological conditions. Introducing fixed, fully edited FLNAR did not hamper normal cell migration but reduced macrophage inflammation and rendered neutrophils less prone to NETosis. In conclusion, loss of FLNA editing correlates with colitis severity, and targeted FLNA editing of myeloid cells might serve as a novel therapeutic approach in intestinal inflammation. SummaryIn this study, Gawish et al. show that RNA editing of the actin cross-linker FLNA is similarly regulated in mice and humans and that the targeted induction of edited FLNAR in myeloid cells governs resistance to DSS-induced colitis, revealing its potential in IBD therapy.

molecular biology↗

bioRxiv2024

Human-derived microRNA 21 regulates indole and L-tryptophan biosynthesis transcripts in a prominent gut symbiont

In the gut, microRNAs (miRNAs) produced by intestinal epithelial cells are secreted into the lumen and can shape the composition and function of the gut microbiome. Crosstalk between gut microbes and the host plays a key role in irritable bowel syndrome (IBS) and inflammatory bowel diseases, yet little is known about how the miRNA-gut microbiome axis contributes to the pathogenesis of these conditions. In this study, we aimed to explore the ability of miR-21, a miRNA that we found decreased in stool samples from IBS patients, to associate with and regulate gut microbiome function. Incubation of human faecal microbiota with miR-21 revealed a rapid association with microbial cells, reproducible across multiple donor samples. Fluorescence-activated cell sorting and sequencing of microbial cells incubated with fluorescently-labelled miR-21 identified organisms belonging to the genera Bacteroides, Limosilactobacillus, Ruminococcus, or Coprococcus which predominantly interacted with miR-21. Surprisingly, these and other genera also interacted with a miRNA scramble control, suggesting that physical interaction and/or uptake of these miRNAs by gut microbiota is not sequence-dependent. Nevertheless, transcriptomic analysis of the gut commensal Bacteroides thetaiotaomicron revealed a miRNA sequence-specific effect on bacterial transcript levels. Supplementation of miR-21, but not of small RNA controls resulted in significantly altered levels of many cellular transcripts and increased transcription of a biosynthetic operon for indole and L-tryptophan, metabolites known to regulate host inflammation and colonic motility. Our study identifies a novel putative miR-21-dependent pathway of regulation of intestinal function through the gut microbiome with implications for gastrointestinal conditions.

microbiology↗

bioRxiv2018

Modulation of ADARs mRNA expression in congenital heart defect patients

Adenosine (A) to inosine (I) RNA editing, is a hydrolytic deamination reaction catalyzed by adenosine deaminase (ADAR) acting on RNA enzymes. RNA editing is a molecular process that involves the post-transcriptional modification of RNA transcripts. Interestingly, few studies have been carried out to determine the role of RNA editing in vascular disease. The current study found that in blood samples positive for congenital heart disease (CHD) ADAR1 and ADAR2 expression change at RNA level was opposite to each other. That is, an increase of ADAR1 mRNA was noticed in human CHD cases, whereas ADAR2 mRNA was vastly down-regulated. The increase in ADAR1 may be explained by the stress induced by CHD. The dramatic decrease in ADAR2 in CHD cases was unexpected and prompted further investigation into its effects on the heart. Therefore we performed expression analysis on a microarray data encompassing ischemic and non-Ischemic cardiomyopathy patient myocardial tissues. A strong down-regulation of ADAR2 was observed in both ischemic and especially non-ischemic cases. However, ADAR1 showed a mild increase in the case of non-ischemic myocardial tissues. To further explore the role of ADAR2 with respect to heart physiology. We selected a protein coding gene filamin B (FLNB). FLNB is known to play an important role in heart development. Although there were no observable changes in its expression, the editing levels of FLNB dropped dramatically in ADAR2-/- mice. We also performed miRNA profiling from ADAR2 -/- mice heart tissue revealed a decrease in expression of miRNAs. It is established that aberrant expression of these miRNAs is often associated with cardiac defects. This study proposes that sufficient amounts of ADAR2 might play a vital role in preventing cardiovascular defects.

molecular biology↗