Biology subjects

Csanyi, G.

Publications and source records attributed to Csanyi, G..

3 recordsLinked to original sources

bioRxiv2026

Loss of the Coronary Artery Disease Risk Gene Leiomodin1 in Vascular Smooth Muscle Cells Triggers Rapid Onset Coronary Atherosclerosis

BackgroundAtherosclerosis is the primary underlying cause of coronary artery disease (CAD). Leiomodin1 is a vascular smooth muscle cell (VSMC)-restricted CAD risk gene whose role in coronary artery pathophysiology is unknown. Global loss of Leiomodin1 causes lethal neonatal visceral myopathy, requiring unique approaches for study in VSMCs. MethodsSeveral distinct Leiomodin1 mutant mouse models were generated by clustered regularly interspaced short palindromic repeats (CRISPR). Control (Lmod1WT) and VSMC-restricted Lmod1 knockout (Lmod1SMKO) mice were subjected to various atherogenic regimens. Atherosclerosis and LMOD1 expression in mouse and human coronary arteries were assessed by histopathology and confocal immunofluorescence microscopy. Coronary arteries from Lmod1WT and Lmod1SMKO mice were analyzed with assorted stains and antibodies, immunogold lineage tracing, spatial metabolomics/transcriptomics, and single-cell RNA sequencing (scRNA-seq). Mouse aortic SMCs from Lmod1WT and Lmod1SMKO mice were subjected to lipid loading with lentiviruses expressing wild-type Lmod1, a nucleation deficient Leiomodin1 (Lmod1ND), or a short hairpin RNA (shRNA) targeting Thrombospondin (Thbs1). ResultsUnder atherogenic conditions, Lmod1SMKO mice displayed unremarkable vessels in several organs but developed diffuse and occlusive coronary atherosclerosis. No such disease was observed in Lmod1WT mice. Time-course studies documented lipid insudation and VSMC foam cell formation in the coronary arteries of Lmod1SMKO mice as early as six days post-regimen. Immunogold lineage tracing demonstrated 46% of coronary plaque cells being of VSMC origin, with most showing evidence of lipid uptake. An intronic deletion of Lmod1, containing a conserved region where the single nucleotide variant associated with CAD exists, showed attenuated LMOD1 expression; heterozygous Lmod1SMKO mice, with a similar reduction in LMOD1, showed no CAD. Spatial metabolomics uncovered multiple lipid species within coronary atheromata of Lmod1SMKO mice, and spatial/scRNA-seq of similar coronary lesions disclosed altered lipid pathways with a consistent elevation in Thbs1. In vitro mechanistic studies revealed lipid accumulation in Lmod1SMKO VSMCs that was rescued by Lmod1WT, Lmod1ND, and Thbs1 shRNA. VSMC-restricted expression of Lmod1ND in mice resulted in negligible coronary atherosclerosis. ConclusionsUnder proatherogenic conditions, Lmod1SMKO mice present with rapidly manifesting coronary atherosclerosis that appears to be independent of the actin nucleation function of LMOD1. Targeting Thbs1 represents a viable strategy to mitigate VSMC foam cell formation. Clinical PerspectiveO_ST_ABSWhat is new?C_ST_ABSO_LIVascular smooth muscle cell (VSMC) loss of Leiomodin1 (Lmod1) causes diffuse and occlusive coronary atherosclerosis in mice, with little or no such disease in other vascular beds. C_LIO_LIA novel immunogold lineage tracing assay shows VSMC migration to the intima as early as six days following an atherogenic regimen, and quantitative studies demonstrate that 46% of coronary plaque cells are of SMC origin. C_LIO_LIThe coronary phenotype appears to be independent of LMOD1s actin nucleation activity, but VSMC lipid uptake is thrombospondin-dependent. C_LI What are the clinical implications?O_LILMOD1 is an annotated smooth muscle cell-restricted risk allele for human coronary artery disease (CAD), offering new insight into the role of smooth muscle cells in atherogenesis. C_LIO_LIThe rapidly manifesting CAD phenotype in Lmod1 knockout mice enables expedited testing of novel therapeutics to mitigate disease progression. C_LIO_LINew insight into LMOD1 pathobiology will help inform further SNV interrogation of the LMOD1 locus for CAD risk in patients. C_LI

pathology↗

bioRxiv2024

Loss of Neurofibromin Induces Inflammatory Macrophage Phenotypic Switch and Retinal Neovascularization via GLUT1 Activation

Persons with neurofibromatosis type 1 (NF1), a tumor predisposition syndrome, are largely protected from diabetes and exhibit evidence of enhanced glucose metabolism, which is replicated in mice harboring Nf1 mutations. A hallmark of NF1-associated neurofibromas and sarcomas is the high density of inflammatory macrophages and targeting macrophages appears efficacious in models of NF1. Inflammatory macrophages rely on glycolysis to rapidly generate ATP; thus, identifying whether neurofibromin, the protein encoded by the NF1 gene, controls glucose uptake and/or glycolysis in macrophages is therapeutically compelling. Using neurofibromin-deficient macrophages and macrophage-specific Nf1 knockout mice, we demonstrate that neurofibromin complexes with glucose transporter 1 (GLUT1) to restrain its activity and that loss of neurofibromin permits Akt2 to facilitate GLUT1 translocation to the membrane in macrophages. In turn, glucose internalization and glycolysis are highly up regulated and provoke putative reparative (M2) macrophages to undergo inflammatory phenotypic switch. Inflammatory M1 macrophages and inflammatory-like M2 macrophages invest the perivascular stroma of tumors and induce pathologic angiogenesis in mice harboring macrophage-specific Nf1 deletion. These studies identify a clear mechanism for the enhanced glycolysis and low risk for diabetes observed in persons with NF1 and provide a novel therapeutic target for manifestations of NF1.

cell biology↗

bioRxiv2023

Hepatocyte-specific disruption of soluble epoxide hydrolase attenuates abdominal aortic aneurysm formation: novel role of the liver in aneurysm pathogenesis

IntroductionInflammation is a key pathogenic feature of abdominal aortic aneurysm (AAA). Soluble epoxide hydrolase (sEH) is a pro-inflammatory enzyme that converts cytochrome P450-derived epoxides of fatty acids to the corresponding diols, and pharmacological inhibition of sEH prevented AAA formation. Both cytochrome P450 enzymes and sEH are highly expressed in the liver. Here, we investigated the role of hepatic sEH in AAA using a selective pharmacological inhibitor of sEH and hepatocyte-specific Ephx2 (which encodes sEH gene) knockout (KO) mice in two models of AAA [angiotensin II (AngII) infusion and calcium chloride (CaCl2) application]. Methods and resultssEH expression and activity were strikingly higher in mouse liver compared with aorta and further increased the context of AAA, in conjunction with elevated expression of the transcription factor Sp1 and the epigenetic regulator Jarid1b, which have been reported to positively regulate sEH expression. Pharmacological sEH inhibition, or liver-specific sEH disruption, achieved by crossing sEH floxed mice with albumin-cre mice, prevented AAA formation in both models, concomitant with reduced expression of hepatic sEH as well as complement factor 3 (C3) and serum amyloid A (SAA), liver-derived factors linked to AAA formation. Moreover, sEH antagonism markedly reduced C3 and SAA protein accumulation in the aortic wall. Co-incubation of liver ex vivo with aneurysm-prone aorta resulted in induction of sEH in the liver, concomitant with upregulation of Sp1, Jarid1b, C3 and SAA gene expression, suggesting that the aneurysm-prone aorta secretes factors that activate sEH and downstream inflammatory signaling in the liver. Using an unbiased proteomic approach, we identified a number of dysregulated proteins [e.g., plastin-2, galectin-3 (gal-3), cathepsin S] released by aneurysm-prone aorta as potential candidate mediators of hepatic sEH induction. ConclusionWe provide the first direct evidence of the livers role in orchestrating AAA via the enzyme sEH. These findings not only provide novel insight into AAA pathogenesis, but they have potentially important implications with regard to developing effective medical therapies for AAA.

pharmacology and toxicology↗