Biology subjects

Chlopicki, S.

Publications and source records attributed to Chlopicki, S..

6 recordsLinked to original sources

bioRxiv2026

Lanifibranor (IVA-337) - a pan-PPAR agonist suppresses TGF-β1-induced cardiac fibrosis and rescues cardiomyocyte function

Background: Cardiac fibrosis is a hallmark of many cardiovascular diseases, driven by sustained fibroblast activation and excessive extracellular matrix deposition, leading to myocardial stiffening and impaired contractility. Current therapies inadequately address this process. This study evaluated the antifibrotic potential of lanifibranor, a balanced pan-peroxisome proliferator-activated receptors (PPARs) agonist, in TGF-beta1-induced cardiac fibrosis. Methods: Human cardiac microtissues, along with 2D and 3D cardiac fibroblast and cardiomyocyte cultures, were used to assess cell viability, structure, metabolism, contractility, and gene expression. Results: Lanifibranor reduced TGF-beta1-induced fibrosis by limiting fibroblast activation and matrix deposition without affecting viability. In fibroblasts, these effects were associated with partial restoration of mitochondrial respiration and reduced focal adhesion maturation. In cardiac microtissues, lanifibranor improved contraction kinetics, decreased profibrotic transcriptional activity, and preserved bioenergetic homeostasis despite altered nucleotide balance. In cardiomyocytes, treatment normalized contractility and calcium handling while maintaining metabolic stability. Conclusions: Lanifibranor attenuates TGF-beta1-driven cardiac fibrosis by combining antifibrotic effects with metabolic and functional improvements in human models.

pharmacology and toxicology↗

bioRxiv2024

Endothelial miR-34a deletion guards against aneurysm development despite endothelial dysfunction

ObjectivesOur previous study reported a reciprocal link between NRF2, a stress-responsive cytoprotective transcription factor, and aortic and endothelial cell (EC) ageing. We also found that NRF2 transcriptional knockout (tKO) mice are prone to abdominal aortic aneurysm (AAA) development. Given that miRNA-34a is a marker of ageing, in this study we explored its relationship with NRF2 and its role in vascular function and AAA formation. Approach and resultsThe experiments were performed in primary human aortic endothelial cells (HAECs) from young and aged donors and mice devoid of NRF2 transcriptional activity and endothelial miR-34a. The normolipidemic mice were challenged with angiotensin II (Ang II) to develop AAA. We show that premature NRF2-dependent aging of aortic endothelial cells (ECs) depends on miR-34a. Infusion of hypertensive Ang II in mice increases miR-34a in the aortic endothelial layer and serum, especially in mice which develop AAA. Mice deficient in endothelial miR-34a (miR-34a{Delta}EC) display severe EC dysfunction. Despite that, such mice are protected from AAA development, also on the NRF2 tKO background. Ang II infusion increases proliferation of intimal ECs in these mice. The protective effect of endothelial miR-34a deletion on AAA formation is reversed by rapamycin that suppresses EC proliferation. MTA2, but not SIRT1, is a direct target of miR-34a abrogating Ang II-induced EC proliferation. ConclusionsThese findings reveal that AAA development in NRF2 tKO mice relies on endothelial miR-34a overexpression. Deletion of endothelial miR-34a protects mice from AAA despite inducing endothelial cell dysfunction. The fine-tuning of EC proliferation may play a therapeutic role in the treatment of aneurysm.

pathology↗

bioRxiv2024

Endogenously produced hydrogen cyanide serves as a novel mammalian gasotransmitter

Small, gaseous molecules, known as gasotransmitters (NO, CO, H2S), are produced endogenously in mammalian cells and serve important biological roles. Hydrogen cyanide, traditionally considered a cytotoxic molecule in mammals, serves as an endogenous mediator in several plants and bacterial species. Here we show that low concentrations of cyanide are generated endogenously in mouse liver and human hepatocytes. Cyanide production is stimulated by glycine, occurs at the low pH of lysosomes and requires peroxidase activity. Cyanide, in turn, is detectable in several cellular compartments. Cyanide is also detectable basally in the blood of mice; its levels increase after treatment of the animals with glycine. Rhodanese activity regulates endogenous cyanide levels. Cyanide, when generated endogenously at an optimal level, exerts stimulatory effects on mitochondrial bioenergetics, cell metabolism and cell proliferation. Dysregulation of endogenous cyanide, either below or above optimal levels, impairs cellular bioenergetics. The regulatory effects of cyanide are in part mediated by posttranslational modification of cysteine residues via protein cyanylation; cyanylated protein residues can be detected basally, and increase after treatment with glycine. Controlled low-dose cyanide supplementation exhibits cytoprotective effects, as demonstrated in hypoxia and reoxygenation models in vitro and in vivo. However, pathologically elevated cyanide production, as demonstrated in nonketotic hyperglycinemia - an autosomal recessive disease of glycine metabolism - is deleterious to the cells.

biochemistry↗

bioRxiv2023

Diosmetin alleviates liver inflammation by improving liver sinusoidal endothelial cell dysfunction.

Background & AimsTumor necrosis factor-alpha (TNF) induces pro-inflammatory activation in liver sinusoidal endothelial cells (LSEC) and liver inflammation. However, knowledge about whether modulating LSEC activation can alleviate liver inflammation is scarce. This study aimed to establish and validate an animal model mimicking LSEC dysfunction observed in patients with elevated plasma levels of TNF, and explore whether vasoactive flavonoid diosmetin could serve as a therapeutic agent for liver inflammation. Approach & ResultsGenetic deletion of Mcpip1 in myeloid leukocytes (Mcpip1fl/flLysMCre) resulted in the development of systemic and liver inflammation in mice. Symptoms were compared with those in liver samples from obese humans with elevated TNF. Mice were treated with diosmetin, and its effectiveness in alleviating liver inflammation was evaluated. Elevated TNF correlated with reduced Mcpip1 expression in peripheral blood mononuclear cells and LSEC dysfunction in obese patients. Mcpip1 knockout in myeloid cells in mice replicated molecular signs observed in human samples. Diosmetin efficiently reduced LSEC activation and liver inflammation in Mcpip1fl/flLysMCre mice. Diosmetins effects may stem from inhibiting NF-{kappa}B-p50 subunit production in TNF-activated endothelial cells. ConclusionsDiosmetin treatment efficiently restricted liver inflammation, despite ongoing systemic inflammation, by diminishing LSEC dysfunction. Mcpip1fl/flLysMCre mice mimic symptoms of liver inflammation observed in humans and can be useful in studies on new anti-inflammatory therapies for the liver. We show that diosmetin, a vasoactive flavonoid that is successfully used in the clinic to treat chronic venous insufficiency, has also strong anti-inflammatory properties in the liver. This suggests that diosmetin treatment may be tested in humans as a supportive therapy for liver inflammation. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=186 HEIGHT=200 SRC="FIGDIR/small/563468v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@1c1c841org.highwire.dtl.DTLVardef@1425cb9org.highwire.dtl.DTLVardef@1d583aaorg.highwire.dtl.DTLVardef@b71f40_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2020

Deletion of Mcpip1 in Mcpip1AlbKO mice recapitulates the phenotype of human primary biliary cholangitis

Background & AimsPrimary biliary cholangitis (PBC) is an autoimmune disease characterized by progressive destruction of the intrahepatic bile ducts. The immunopathology of PBC involves excessive inflammation; therefore, negative regulators of inflammatory response, such as Monocyte Chemoattractant Protein-1-Induced Protein-1 (MCPIP1, alias Regnase1) may play important roles in the development of PBC. The aim of this work was to verify whether Mcpip1 expression protects against development of PBC. MethodsGenetic deletion of Zc3h12a was used to characterize the role of Mcpip1 in the pathogenesis of PBC. 6-52-week-old Mcpip1fl/fl and Mcpip1AlbKO mice were used for immunohistochemical, biochemical and molecular tests. ResultsWe found that Mcpip1 deficiency in the liver recapitulates most of the features of human PBC, in contrast to mice with Mcpip1 deficiency in myeloid cells (Mcpip1LysMKO mice), which present with robust myeloid cell-driven systemic inflammation. In Mcpip1AlbKO livers, intrahepatic bile ducts displayed proliferative changes with inflammatory infiltration, bile duct destruction, and fibrosis leading to cholestasis. In plasma, increased concentrations of IgG, IgM, and AMA autoantibodies (anti-PDC-E2) were detected. Interestingly, the phenotype of Mcpip1AlbKO mice was robust in 6-week-old and 52-week-old mice, but milder in 12-24-week-old mice, suggesting early prenatal origin of the phenotype and age-dependent progression of the disease. Hepatic transcriptome analysis of 6-week-old and 24-week-old Mcpip1AlbKO mice showed 812 and 8 differentially expressed genes (DEGs), respectively, compared with age-matched control mice, and revealed a distinct set of genes compared to those previously associated with development of PBC. ConclusionsThe phenotype of Mcpip1AlbKO mice recapitulates most of the features of human PBC, and demonstrates early prenatal origin and age-dependent progression of PBC. Therefore, Mcpip1AlbKO mice provide a unique model for the study of PBC. Lay summaryDeletion of hepatic Mcpip1 in Mcpip1AlbKO mice leads to development of PBC that recapitulates phenotype of human patients. These animals, show early prenatal origin and age-dependent progression of the disease. Thus, Mcpip1AlbKO mice provide a unique model for studying PBC.

pathology↗

bioRxiv2018

Extracellular Adenine Nucleotide and Adenosine Metabolism in Calcific Aortic Valve Disease

Extracellular nucleotide catabolism contributes to immunomodulation, cell differentiation and tissue mineralization by controlling nucleotide and adenosine concentrations and its purinergic effects. Disturbances of purinergic signaling in valves may lead to its calcification. This study aimed to investigate the side-specific changes in extracellular nucleotide and adenosine metabolism in the aortic valve during calcific aortic valve disease (CAVD) and to identify the individual enzymes that are involved in these pathways as well as their cellular origin.\n\nStenotic aortic valves were characterized by reduced levels of extracellular ATP removal and impaired production of adenosine. Respectively, already reduced levels of extracellular adenosine were immediately degraded further due to the elevated rate of adenosine deamination. For the first time, we revealed that this metabolic pattern was observed only on the fibrosa surface of stenotic valve that is consistent with the mineral deposition on the aortic side of the valve. Furthermore, we demonstrated that non-stenotic valves expressed mostly ecto-nucleoside triphosphate diphosphohydrolase 1 (eNTPD1) and ecto-5nucleotidase (e5NT), while stenotic valves ecto-nucleotide pyrophosphatase/ phosphodiesterase 1, alkaline phosphatase and ecto-adenosine deaminase (eADA). On the surface of endothelial cells, isolated from non-stenotic valves, high activities of eNTPD1 and e5NT were found. Whereas, in valvular interstitial cells, eNPP1 activity was also detected. Stenotic valve immune infiltrate was an additional source of eADA. We demonstrated the presence of A1, A2a and A2b adenosine receptors in both, non-stenotic and stenotic valves with diminished expression of A2a and A2b in the former.\n\nExtracellular nucleotide and adenosine metabolism that involves complex ecto-enzyme pathways and adenosine receptor signaling were adversely modified in CAVD. In particular, diminished activities of eNTPD1 and e5NT with the increase in eADA that originated from valvular endothelial and interstitial cells as well as from immune inflitrate may affect aortic valve extracellular nucleotide concentrations to favor a proinflammatory milieu, highlighting a potential mechanism and target for CAVD therapy.

biochemistry↗