Project description:The role of lipid metabolism in bone metastasis has not been documented. Here, by using an in vivo CRISPR activation screening system coupled with positive selection, we identify acyl-CoA binding protein (ACBP) as a previously undescribed bone metastasis driver. In non-metastatic cancer cells, overexpression of wild-type ACBP, but not the acyl-CoA binding deficient mutant, stimulates fatty acid oxidation (FAO) and bone metastasis. Conversely, knockout of ACBP in highly bone-metastatic cells abrogates metastatic bone colonization. Mechanistically, ACBP-mediated FAO boosts ATP and NADPH production, reduces reactive oxygen species, and inhibits lipid peroxidation and ferroptosis. ACBP expression correlates with metabolic signaling, bone-metastatic ability, and poor clinical outcomes. Notably, FAO blockade or treatment with a ferroptosis inducer inhibits bone metastasis. Altogether, our findings reveal the role of lipid metabolism in tumor cell adaptation and thriving in the bone, and suggests that agents that target FAO or induce ferroptosis hold potential as bone metastasis drugs.
Project description:Floodings already have a nearly 60% share in the worldwide damage to crops provoked by natural disasters. Climate change will cause plants to be even more frequently exposed to oxygen limiting conditions (hypoxia) in the near future due to heavy precipitation and concomitant waterlogging or flooding events in large areas of the world. Although the homeostatic regulation of adaptive responses to low oxygen stress in plants is well described, it remained unknown by which initial trigger the molecular response to low-oxygen stress is activated. Here, we show that a hypoxia-induced decline of the ATP level of the cell reduces LONG-CHAIN ACYL-COA SYNTHETASE (LACS) activity, which leads to a shift in the composition of the acyl-CoA pool. High oleoyl-CoA levels release the transcription factor RELATED TO APETALA 2.12 (RAP2.12) from its interaction partner ACYL-COA BINDING PROTEIN (ACBP) at the plasma membrane to induce low oxygen-specific gene expression. We show that different acyl-CoAs provoke unique molecular responses revealing a novel role as cellular signalling component also in plants. In terms of hypoxia signalling, dynamic acyl-CoA levels integrate the cellular energy status into the oxygen signalling cascade with ACBP and RAP2.12 being the central hub. The conserved nature of the ACBP:RAP2.12 module in crops and the novel mechanistic understanding of how low-oxygen stress responses are initiated by oleoyl-CoA in plants provide useful leads for enhancing future food security.
Project description:G-quadruplex structure (G4) is a type of DNA secondary structure that widely exists in the genomes of many organisms. G4s are believed to participate in multiple biological processes. Acyl- CoA binding protein (ACBP), a ubiquitously expressed and highly conserved protein in eukaryotic cells, plays important roles in lipid metabolism by transporting and protecting acyl-CoA esters. Here, we report the functional identification of a G4 in the promoter of the ACBP gene in silkworm and human cancer cells. We found that G4 exists as a conserved element in the promoters of ACBP genes in invertebrates and vertebrates. The BmACBP G4 bound with G4-binding protein LARK regulated BmACBP transcription, which was blocked by the G4 stabilizer pyridostatin (PDS) and G4 antisense oligonucleotides. PDS treatment with 5 th instar silkworm larvae decreased the BmACBP expression and triacylglycerides (TAG) level, resulting in reductions in fat body mass, body size and weight and growth and metamorphic rates. PDS treatment and knocking out of the HsACBP G4 in human hepatic adenocarcinoma HepG2 cells inhibited the expression of HsACBP and decreased the TAG level and cell proliferation. Altogether, our findings suggest that G4 of the ACBP genes is involved in regulation of lipid metabolism processes in invertebrates and vertebrates.
Project description:The ACBP knockout were created by targeted disruption of the gene in mice. The expression profiling was performed on liver tissue from ACBP-/- (KO) and +/+ (WT) mice at the age of 21 days, which in our study is the time immediately before weaning. The mice used for this experiment were taken directly away from their mother. Thus, having free access to chow and breast milk until sacrificed at 8-11am
Project description:The defective activity of brown adipose tissue (BAT) is linked to obesity and cardiometabolic diseases. While there is extensive knowledge about the biological signals that trigger BAT thermogenesis, information regarding active repressors that may contribute to the pathological impairment of BAT function is quite limited. Acyl CoA-Binding Protein (ACBP), also known as Diazepam Binding Inhibitor (DBI), is a protein with intracellular functions related to lipid metabolism. It can also be secreted and act as a circulating regulatory factor that affects multiple tissues and organs. We discovered that ACBP expression and release in BAT are suppressed by noradrenergic, cAMP-dependent signals that stimulate thermogenesis. This regulation occurs through mechanisms involving gene expression and autophagy-related processes. Mice with targeted ablation of the Acbp gene in brown adipocytes exhibit enhanced BAT thermogenic activity and protection against obesity and glucose intolerance induced by a high-fat diet. This is associated with a remodeling of the BAT transcriptome, characterized by the induction of genes related to BAT thermogenesis. Treatment of brown adipocytes with exogenous ACBP suppressed oxidative activity, lipolysis, and the expression of genes associated with thermogenesis. ACBP inhibits the noradrenergic-induced phosphorylation of p38 MAP kinase and CREB, major intracellular mediators of brown adipocyte thermogenesis. Our findings identify the ACBP system as a crucial auto-regulatory repressor of BAT thermogenesis, which responds reciprocally to the noradrenergic induction of BAT activity.
Project description:Acyl coenzyme A binding protein (ACBP), encoded by the diazepam binding protein (DBI) gene, plays a pivotal role in stimulating appetite and lipo-anabolic reactions, showing correlations with laboratory indications of metabolic syndrome in ostensibly healthy individuals. In a screening effort targeting inhibitors of ACBP/DBI expression among distinct neuroendocrine factors, we discovered that glucocorticoids induce ACBP/DBI secretion in cultured cells. In mouse models of iatrogenic Cushing syndrome, antibody-mediated neutralization of ACBP/DBI prevented the metabolic consequences of prolonged glucocorticoid administration. Our findings suggest that a surge in extracellular ACBP/DBI may mediate crucial aspects of Cushing syndrome.
Project description:The ACBP knockout were created by targeted disruption of the gene in mice. The expression profiling was performed on liver tissue from ACBP-/- (KO) and +/+ (WT) mice at the age of 21 days, which in our study is the time immediately before weaning. The mice used for this experiment were taken directly away from their mother. Thus, having free access to chow and breast milk until sacrificed at 8-11am 15 ACBP-/- and 15 +/+ control mice divided into 6 groups (KO1, KO2, KO3, WT1, WT2 and WT3) with 5 individuals in each group were used for this study.
Project description:The plasma concentrations of acyl coenzyme A binding protein (ACBP, also known as diazepam-binding inhibitor, DBI, or ‘endozepine’) increase with age and obesity, two parameters that are also the most important risk factors for cancer. In mice bearing MCA205 fibrosarcoma, antibody mediated ACBP/DBI neutralization enhanced the anticancer T-cell response in the context of chemoimmunotherapy. T-cells infiltrating MCA205 tumors were sorted and submitting to single-cell TCR sequencing and single-cell RNA sequencing (scRNAseq) to identify the mechanisms driving this improvement.