Biology subjects

Razani, B.

Publications and source records attributed to Razani, B..

11 recordsLinked to original sources

bioRxiv2026

Impaired proteostasis is an early feature of the diabetic heart in humans and mice

Diabetes and obesity increase cardiac lipid levels leading to cardiomyopathy and heart failure. We hypothesized that intermittent fasting would reduce cardiac lipid levels. Surprisingly, intermittent fasting increased myocardial triglyceride content, but rescued mortality and attenuated cardiomyopathy in mice overexpressing cardiomyocyte acyl-CoA synthetase 1 (MHC-ACSL1). Lipid overload caused cardiomyocyte accumulation of polyubiquitinated protein aggregates containing desmin, a scaffolding intermediate filament protein, which intermittent fasting prevented. Furthermore, intermittent fasting reversed elevated myocardial C16:0 ceramide content, and knockdown of ceramide synthase CerS5 and CerS6 reduced palmitate-induced protein aggregation, highlighting a role for C16:0 ceramides in this pathology. Conversely, impairing aggrephagy with cardiomyocyte-specific p62 ablation induced heart failure in mice fed a high-fat diet, with paradoxically reduced cardiac lipid content. Crucially, non-failing diabetic human hearts also exhibited protein aggregate pathology. Taken together, these results demonstrate that impaired proteostasis characterizes cardiomyopathy from cardiac lipid overload and identify a promising new therapeutic target for this condition.

molecular biology↗

bioRxiv2026

Single Cell Mapping Identifies CD14+ Macrophages as Central Orchestrators of CD8+ T Cell Driven Immune Niches in clinical Type 1 diabetes

The authors have withdrawn this manuscript after identifying an error in the annotation of donor disease status in one or more datasets used in the study. The error arose from inadequate or ambiguous disease-status labeling in the corresponding GEO dataset at NCBI. The authors personally communicated with the dataset depositor to verify the disease status of the relevant samples. Subsequent verification indicated that the deposited metadata required correction to accurately reflect the disease status of these samples, which may affect the results and interpretation of the study. The authors therefore took the initiative to work with the GEO/NCBI database administrators to correct the relevant sample annotations and are currently reassessing the analyses using the corrected metadata. The authors believe that withdrawal of the current version is appropriate until this reassessment is complete and a revised version can be prepared. This withdrawn version should not be cited or relied upon as a reference until a revised version is made available. Any questions regarding the withdrawal or ongoing reassessment should be directed to the corresponding author.

pathology↗

bioRxiv2025

Activated fatty acid synthesis pathway in macrophages propagates pathogenic fibroblast expansion after myocardial infarction

Metabolic pathways, such as fatty acid oxidation and oxidative phosphorylation, can modulate inflammatory cells. However, little is known about the effects of the fatty acid synthesis pathway in macrophages on inflammation and cardiac remodeling after myocardial infarction (MI). Using spatial metabolomics, here we show that cardiac macrophages residing in the infarct synthesize de novo fatty acids and increase the production of fatty acid enzymes including ACLY and FASN. Mice deficient in myeloid Acly and Fasn have improved cardiac function after MI and reduced fibrosis. Combining Cleavage Under Targets and Release Using Nuclease (CUT&RUN), RNA sequencing analysis of Acly-/-macrophages, and macrophage-specific in vivo gene silencing, we demonstrate that ACLY acetylates the promoter region of the upstream regulator Krt17, which drives the production of pro-fibrotic cytokines, including IL-33. Single-cell RNA sequencing of cardiac fibroblasts shows that the expansion of a population of fibroblasts (Fibroblast 5) expressing high levels of extracellular matrix genes after MI is confined in the absence of macrophage Acly. Finally, the analysis of spatial multi-omics data of human hearts with MI uncovers myofibroblasts with the Fibroblast 5 gene signature. These myofibroblasts are located near cardiac macrophages expressing high levels of ACLY. In summary, we show that macrophage ACLY and FASN are deleterious in MI pathogenesis.

immunology↗

bioRxiv2025

Induction of TFEB promotes Kupffer cell survival and reduces lipid accumulation and inflammation in MASLD

Kupffer cells (KCs) are the tissue-resident macrophage of the liver where they serve a critical role in maintaining liver tissue homeostasis and as a filter for circulation. The composition of liver macrophages changes during metabolic dysfunction-associated liver disease (MASLD), with the loss of resident KCs being a hallmark of disease progression. The mechanism(s) and consequences of KC death in metabolic liver disease have yet to be defined. Transcription factor EB (TFEB) is a master regulator of lysosome function and lipid metabolism which has been shown to protect macrophages from lipid stress in atherosclerosis. We hypothesized that TFEB would improve KC fitness in MASLD. To investigate this possibility, we created a transgenic mice in which TFEB was induced specifically in KCs. We found that TFEB induction protected KCs from cell death in two mouse models of MASLD. KC preservation through TFEB induction reduced liver steatosis via a mechanism that was dependent on macrophage lysosomal lipolysis and mitochondrial fatty acid oxidation. The protection from cell death in TFEB KCs was the result of reduced oxidative stress and ferroptosis through a mechanism that involved enhanced NADPH levels. Together, we provide evidence that TFEB promotes KC fitness during MASLD and orchestrates beneficial effects on liver pathology, thus providing potential targets to develop cell-specific therapeutics.

immunology↗

bioRxiv2025

A20's Linear Ubiquitin Binding Motif Restrains Pathogenic Activation of TH17/22 cells and IL-22 Driven Enteritis

A20, encoded by the TNFAIP3 gene, is a protein linked to Crohns disease and celiac disease in humans. We now find that mice expressing point mutations in A20s M1 ubiquitin binding motif (ZF7) spontaneously develop proximate enteritis that requires both luminal microbes and T cells. Cellular and transcriptomic profiling reveal expansion of TH17/22 cells and aberrant expression of IL-17A and IL-22 in intestinal lamina propria of A20ZF7 mice. While deletion of IL-17A from A20ZF7/ZF7 mice exacerbates enteritis, deletion of IL-22 abrogates intestinal epithelial cell hyperproliferation, barrier dysfunction, and alarmin expression. A20ZF7/ZF7 TH17/22 cells autonomously express more ROR{psi}t and IL-22 after differentiation in vitro. ATAC sequencing identified an enhancer region upstream of the Il22 gene in A20ZF7/ZF7 T cells, and this enhancer demonstrated increased activating histone acetylation coupled with exaggerated Il22 transcription. Finally, CRISPR/Cas9-mediated ablation of A20ZF7 in human T cells increases ROR{psi}t expression and IL22 transcription. These studies link A20s M1 ubiquitin binding function with ROR{psi}t expression, epigenetic activation of TH17/22 cells, and IL-22 driven enteritis.

immunology↗

bioRxiv2024

Phosphorylation of CRYAB Induces a Condensatopathy to Worsen Post-Myocardial Infarction Left Ventricular Remodeling.

Protein aggregates are emerging therapeutic targets in rare monogenic causes of cardiomyopathy and amyloid heart disease, but their role in more prevalent heart failure syndromes remains mechanistically unexamined. We observed mis-localization of desmin and sarcomeric proteins to aggregates in human myocardium with ischemic cardiomyopathy and in mouse hearts with post-myocardial infarction ventricular remodeling, mimicking findings of autosomal-dominant cardiomyopathy induced by R120G mutation in the cognate chaperone protein, CRYAB. In both syndromes, we demonstrate increased partitioning of CRYAB phosphorylated on serine-59 to NP40-insoluble aggregate-rich biochemical fraction. While CRYAB undergoes phase separation to form condensates, the phospho-mimetic mutation of serine-59 to aspartate (S59D) in CRYAB mimics R120G-CRYAB mutants with reduced condensate fluidity, formation of protein aggregates and increased cell death. Conversely, changing serine to alanine (phosphorylation-deficient mutation) at position 59 (S59A) restored condensate fluidity, and reduced both R120G-CRYAB aggregates and cell death. In mice, S59D CRYAB knock-in was sufficient to induce desmin mis-localization and myocardial protein aggregates, while S59A CRYAB knock-in rescued left ventricular systolic dysfunction post-myocardial infarction and preserved desmin localization with reduced myocardial protein aggregates. 25-Hydroxycholesterol attenuated CRYAB serine-59 phosphorylation and rescued post-myocardial infarction adverse remodeling. Thus, targeting CRYAB phosphorylation-induced condensatopathy is an attractive strategy to counter ischemic cardiomyopathy.

cell biology↗

bioRxiv2022

Decoding the Variant-to-Function Relationship for LIPA, a Risk Locus for CAD

Translating human genomic discoveries into mechanistic insights requires linking genetic variations to candidate genes and their causal functional phenotypes. Genome-wide association studies have consistently identified LIPA as a risk locus for coronary artery disease (CAD), with previous expression quantitative trait loci (eQTL) analyses prioritizing LIPA as a candidate causal gene. However, functional studies elucidating the causal variants, regulatory mechanisms, target cell types, and their causal impact on atherosclerosis have been lacking. To address this gap, we applied functional genomics and experimental mouse models to establish the variant-to-function relationship at the LIPA locus. Our findings show that CAD risk alleles in the LIPA locus increase LIPA expression and enzyme activity specifically in monocytes/macrophages by enhancing PU.1 binding to an intronic enhancer region that interacts with the LIPA promoter. In myeloid Lipa-overexpressing mice, we observed larger atherosclerotic lesions accompanied by altered macrophage function, including increased macrophage accumulation due to enhanced monocyte recruitment, reduced neutral lipid accumulation, and upregulation of integrin and extracellular matrix pathways. Our work establishes a direct causal link between LIPA risk alleles and increased monocyte/macrophage LIPA that exacerbates atherosclerosis, bridging human functional genomic evidence to the mechanistic understanding of CAD. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=58 SRC="FIGDIR/small/516293v2_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@11ce287org.highwire.dtl.DTLVardef@15c201aorg.highwire.dtl.DTLVardef@13f90c9org.highwire.dtl.DTLVardef@3aa3be_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

bioRxiv2022

Spatially Resolved Metabolites in Stable and Vulnerable Human Atherosclerotic Plaques Identified by Mass Spectrometry Imaging

Impairments in carbohydrate, lipid, and amino acid metabolism drive features of plaque instability. However, where these impairments occur within the atheroma remains largely unknown. Therefore, we sought to characterize the spatial distribution of metabolites within stable and unstable atherosclerosis in both the fibrous cap and necrotic core. Atherosclerotic tissue specimens were scored based on the Stary classification scale and subdivided into stable and unstable atheromas. After performing mass spectrometry imaging (MSI) on these samples, we identified over 850 metabolite-related peaks. Using MetaboScape, METASPACE, and HMDB, we confidently annotated 170 of these metabolites and found over 60 of these were different between stable and unstable atheroma. We then integrated these results with an RNA-sequencing dataset comparing stable and unstable human atherosclerosis. Upon integrating our MSI results with the RNA-seq dataset, we discovered that pathways related to lipid metabolism and long-chain fatty acids were enriched in stable plaques, whereas reactive oxygen species, aromatic amino acid, and tryptophan metabolism were increased in unstable plaques. Acylcarnitines and acylglycines were increased in stable plaques whereas tryptophan metabolites were enriched in unstable plaques. Evaluating spatial differences in stable plaques revealed lactic acid in the necrotic core, whereas pyruvic acid was elevated in the fibrous cap. In unstable plaques, 5-hydroxyindole-acetic acid was enriched in the fibrous cap. Our work herein represents the first step to defining an atlas of metabolic pathways involved in plaque destabilization in human atherosclerosis. We anticipate this will be a valuable resource and open new avenues of research in cardiovascular disease. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=199 SRC="FIGDIR/small/494038v1_ufig1.gif" ALT="Figure 1"> View larger version (59K): org.highwire.dtl.DTLVardef@111368org.highwire.dtl.DTLVardef@1112d99org.highwire.dtl.DTLVardef@c8cdb2org.highwire.dtl.DTLVardef@13895d6_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2021

Microbial signals and lymphotoxin drive TNF-independent death of A20 and ABIN-1 deficient epithelium

Anti-TNF antibodies are effective for treating patients with inflammatory bowel disease (IBD), but many patients fail to respond to anti-TNF therapy, highlighting the importance of TNF-independent disease. We previously demonstrated that acute deletion of two IBD susceptibility genes, A20 (Tnfaip3) and Abin-1 (Tnip1), in intestinal epithelial cells (IECs) sensitizes mice to both TNF-dependent and TNF-independent death. Here we show that TNF-independent IEC death after A20 and Abin-1 deletion is rescued by germ-free derivation or deletion of MyD88, while deletion of Trif provides only partial protection. Combined deletion of Ripk3 and Casp8, which inhibits both apoptotic and necroptotic death, completely protects against death after acute deletion of A20 and Abin-1 in IECs. A20 and Abin-1-deficient IECs are sensitized to TNF-independent, TNFR-1-mediated death in response to lymphotoxin alpha (LT) homotrimers. Blockade of LT in vivo reduces weight loss and improves survival when combined with partial deletion of MyD88. These data show that microbial signals, MyD88, and LT all contribute to TNF-independent intestinal injury. SUMMARYHere we show that germ-free derivation, MyD88 deletion, combined Ripk3 and Casp8 deletion, or anti-LT, all reduce TNF-independent intestinal injury after A20 and Abin-1 deletion.

immunology↗

bioRxiv2021

TRAF2, an innate immune sensor, reciprocally regulates mitophagy and inflammation to maintain cardiac myocyte homeostasis.

Mitochondrial damage triggers cell death signaling with catastrophic consequences in long-lived and irreplaceable cells, such as cardiac myocytes. Sensing of leaked mitochondrial DNA upon mitochondrial damage is also a potent trigger of inflammation. Whether the innate immune response pathways monitor mitochondrial damage in mitochondria-rich cardiac myocytes to prevent inflammation and cell death, remains unknown. TRAF2, an adaptor protein downstream of innate immune receptors, localizes to the mitochondria in the unstressed heart, with increased mitochondrial targeting in cardiomyopathic human hearts and after cardiac ischemia-reperfusion injury in mice. Inducible cardiomyocyte-specific deletion of TRAF2 in young adult mice impairs mitophagy with rapid decline in mitochondrial quality, upregulates TLR9 expression in cardiac myocytes, and results in inflammation and cell death manifesting as a fulminant cardiomyopathy. Preventing TLR9-mediated mitochondrial DNA sensing and resultant inflammation provides a short-term reprieve from cardiomyopathy, but persistence of damaged mitochondria results in long-term recrudescence. Restoration of wild-type TRAF2, but not the E3 ubiquitin ligase deficient mutant, improves mitochondrial quality and rescues cardiomyopathy to restore homeostasis. Thus, the innate immune response acts via TRAF2 as the first line of defense against mitochondrial damage by orchestrating homeostatic mitophagy to dampen myocardial inflammation and prevent cell death.

cell biology↗

bioRxiv2020

SVEP1, a novel human coronary artery disease locus, promotes atherosclerosis

A low-frequency variant of SVEP1, an extracellular matrix protein, is associated with risk of coronary disease in humans independent of plasma lipids. Despite a robust statistical association, however, it was unclear if and how SVEP1 might contribute to atherosclerosis. Here, using Mendelian randomization and complementary mouse models, we provide evidence that SVEP1 promotes atherosclerosis in humans and mice. We find that SVEP1 is expressed by vascular smooth muscle cells (VSMCs) within the atherosclerotic plaque. VSMCs also interact with SVEP1, causing proliferation and dysregulation of key differentiation pathways, including integrin and Notch signaling. Fibroblast growth factor receptor transcription increases in VSMCs interacting with SVEP1, and is further increased by the coronary disease-associated SVEP1 variant. These effects ultimately drive inflammation and promote atherosclerosis. Taken together, our results suggest that VSMC-derived SVEP1 is a pro-atherogenic factor, and support the concept that pharmacological inhibition of SVEP1 should protect against atherosclerosis in humans.

genetics↗