Project description:Evidence supports the contribution of long non-coding RNAs (lncRNAs) and ferroptosis to traumatic brain injury (TBI) pathogenesis. However, lncRNA regulation in TBI-induced ferroptosis remains poorly understood. Herein, we identified an lncRNA, named noncoding transcript of chemokine (C-C motif) ligand 4 (Ccl4) overlapping (Ntoco), which was upregulated in TBI mice. The upregulation was initiated by hypoxia ischemia induced lower enrichment of H3K27me3 on the Ntoco promoter. Ntoco knockdown inhibited neuron ferroptosis, ameliorated spatial memory and lesion volume following TBI. Ntoco overexpression promoted neuron ferroptosis and recruited microglia to provoke an inflammatory response via Ccl4. Mechanistically, Ntoco facilitated K48-linked ubiquitination and protein degradation by binding to Hnrnpab, which suppressed NF-κB/Lcn2 signal axis activation, including decreased phosphorylation of IkBα, increased phosphorylation of IKKα/β, nuclear translocation of the NF-κB p65 subunit, and elevated Lcn2 expression. These data indicated that targeting Ntoco to mitigate ferroptosis might be a potential therapeutic strategy for TBI.
Project description:Ferroptosis, a recently discovered form of regulated cell death, has been closely linked to tumor progression. However, the underlying mechanism of ferroptosis in non-small cell lung cancer (NSCLC) remains unclear. In this study, we conducted transcriptome sequencing on NSCLC samples. Overall, our study suggests that suppressing LCN2 can effectively inhibit the development of NSCLC by promoting ferroptosis
Project description:COPD patients are largely asymptomatic until later stages when prognosis is generally poor. Here, by shifting the focus forward to pre-COPD and smoking stages, we found the peak of reactive oxygen species (ROS) level and hypoxia character are enriched in pre-COPD samples, and hypoxia inducible factor (HIF)-3α is the key factor. Smoking induced regional tissue hypoxia and emphysema have been found in COPD patients. However, the mechanisms underlying hypoxia especially HIF-3α and COPD have not been investigated. In this study, by leveraging scRNA-seq and EpCAM co-localization analysis we identified HIF-3α is downregulated in alveolar epithelial cells in COPD. In vitro experiments using lentivirus transfection, bulk-RNA seq and RSL3 we found the activation of HIF-3α-GPx4 axis inhibits alveolar epithelial cell ferroptosis under the treatment of cigarettes smoking extracts (CSE). Further results from SftpcCreert2/+R26LSL-Hif3a knock-in mice demonstrated overexpression of HIF-3α inhibits alveolar epithelial cells ferroptosis and prevents the declining of lung function. Our data suggest the activation of HIF-3α-GPx4 axis prevents COPD by inhibiting alveolar epithelial cells ferroptosis. By leveraging this comprehensive analysis method, more promising treatment targets will be found and enhance our understanding to the pathogenesis.
Project description:Chronic obstructive pulmonary disease (COPD) is currently the fourth leading cause of morbidity and mortality in the world and is predicted to be the third leading cause of death. It is characterized by chronic airway inflammation, lung destruction and remodeling, resulting in irreversible airflow obstruction. We utilized single cell RNA-sequencing (scRNA-Seq) to identify ferroptotic differences and associated biological processes involved in the pathogenesis of COPD. We performed scRNA-Seq on lung tissue obtained from donors with non-COPD and mild-to-moderate COPD to identify disease-related genes within different cell types. We identified two populations of alveolar macrophages (AMs) in the human lung that were dysregulated in COPD patients. We discovered that M2-like AMs modulate susceptibility to ferroptosis by disrupting lipid and iron homeostasis both in vivo and in vitro. The discrepancy in sensitivity to ferroptosis can be determined and regulated by HO-1. In contrast, M1-like AMs showed the ability to attenuate oxidative stress and exert resistance to ferroptosis. In addition, the expression of genes within M2-like AMs is also involved in defects in phagocytosis and lysosome distortion. Present scRNA-seq transcriptomic analysis provides a rich data source to further explore lung health and disease, and the development of therapeutic strategies specifically targeting ferroptosis-sensitive alveolar macrophages might be used to develop therapeutic targets..
Project description:Ferroptosis, a cell death pathway driven by lipid peroxidation, is implicated in several human diseases including cancer. Although ferroptosis is entwined with apoptosis, it currently has no characteristic biomarkers or gene signature. In this project we established a continuous phenotypic gradient between ferroptosis and apoptosis and coupled it to transcriptomic and metabolomic landscapes. Omics and mechanistic studies revealed that ferroptosis was associated with enhanced MITF activity, lysosomal function, glutaminolysis, TCA cycle, and activation of ATF4, while its transition into apoptosis was attributed to enhanced ER-stress, ATF4/CHOP switch and PE/PC metabolic shift. The gradual ferroptosis-to-apoptosis transcriptomic landscape was used to generate a unique, unbiased transcriptomic predictor, the Gradient Gene Set (GGS), which classified ferroptosis and apoptosis with high accuracy. Further GGS optimization and datasets analysis of various ferroptotic and apoptotic responses revealed highly specific ferroptosis biomarkers, which were robustly validated in vitro and in vivo. A subset of the GGS was correlated with poor prognosis in breast cancer patients and in PDX models and was found to consist of different ferroptosis repressors, including PDAP1, whose knockdown suppressed breast tumor growth in a mouse model. Collectively, this study highlights molecular switches between ferroptosis and apoptosis, uncovering a highly prognostic predictive ferroptosis gene signature, pointing to a few ferroptosis repressors for targeted breast cancer therapy.
Project description:Lipotoxicity, the accumulation of lipids in non-adipose tissues, alters the metabolic transcriptome and mitochondrial metabolism in skeletal muscle. The mechanisms involved remain poorly understood. Here we show that lipotoxicity increased histone deacetylase 4 (HDAC4) and histone deacetylase 5 (HDAC5), which reduced the expression of metabolic genes and oxidative metabolism in skeletal muscle. This metabolic reprogramming was linked with reduced expression of p53-dependent genes that mediate apoptosis and ferroptosis, which preserved cell viability in response to lipotoxicity. Mechanistically, impaired mitochondrial metabolism reduced acetylation of p53 at K120, a modification required for transcriptional activation of apoptosis, while redox drivers of ferroptosis were also reduced. Overexpression of loss-of-function HDAC4 and HDAC5 mutants in skeletal muscle of obese db/db mice enhanced oxidative capacity, increased apoptosis and ferroptosis and reduced muscle mass. This study identifies HDAC4 and HDAC5 as repressors of the oxidative state of skeletal muscle, and that this metabolic reprogramming, considered deleterious for normal metabolism, is critical to preserve muscle integrity in response to lipotoxicity.
Project description:Lipocalin-2 (LCN2) is a secreted protein involved in innate immunity and also has been associated with several cardiometabolic traits. We examined LCN2 expression in a panel of diverse inbred mouse strains and observed a striking sex difference. Adipose LCN2 was associated with obesity, insulin resistance, dyslipidemia, and hepatic steatosis in females but not males. We expressed LCN2 either in adipose or liver in a tissue specific manner on the background of a whole-body knockout mouse. Adipose LCN2 expression, acting in an autocrine/paracrine manner, promoted metabolic disturbances in females but not males, whereas liver LCN2 expression had no impact on the traits examined. The adipose expression was accompanied by adipose inflammation, fibrosis, and mitochondrial dysfunction, contributing in part to the metabolic disorders. We also show that LCN2 inversely regulates its receptor, LRP2 (or megalin), in a sex-specific manner. Our results demonstrate striking sex- and tissue- specific functions of LCN2.
Project description:Acute graft-versus-host disease (aGVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation (allo-HCT). Strategies to promote intestinal tissue tolerance during aGVHD may improve patient outcomes. Using single-cell RNA-sequencing, we identified a Lipocalin-2 (LCN2)-expressing neutrophil population in mice with intestinal aGVHD. Transfer of LCN2-overexpressing neutrophils or treatment with recombinant LCN2 reduced aGVHD-severity, while the lack of epithelial or hematopoietic LCN2 enhanced aGVHD severity and caused microbiome alterations. Mechanistically, LCN2 induced IGF-1R signaling in macrophages via the LCN2 receptor Slc22A17, which increased IL-10 production while reducing MHC-II expression. Transfer of LCN2-pretreated macrophages reduced aGVHD severity. LCN2-treatment did not reduce graft-versus-leukemia effects. In aGVHD patients LCN2 expression correlated with IL-10 expression in intestinal biopsies. We identified a novel intestinal LCN2+ neutrophil population that reduces aGVHD-severity by decreasing MHC-II expression while increasing IL-10 production in macrophages. Administration of LCN2 presents a novel approach against aGVHD to be tested in clinical trials.