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: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.
Project description:The ER-resident prote in fat-inducing transcript 2 (FIT2) catalyzes acyl-CoA cleavage in vitro, and in cells is required for endoplasmic reticulum (ER)homeostasis and normal lipid storage. The gene encoding FIT2 is essential for viability of mice and worms. Whether FIT2 acts as anacyl-CoA diphosphatase in vivo and how this activity affects liver, where the protein was discovered,is unknown. Here, we report that hepatocyte-specific Fitm2 knockout (FIT2-LKO) mice exhibited elevated acyl-CoA levels, ER stress, and signs of liver injury. FIT2-LKO mice had increased triglyceride (TG) content in liver when fed a chow diet, compared with control littermates due in part to impaired secretion of TG-rich lipoproteins and reduced capacity for fatty acid oxidation. Challenging FIT2-LKO mice with a high-fat diet to increase FIT2 acyl-CoA substrates worsened hepatic ER stress and liver injury, yet unexpectedly reversed the steatosis phenotype, similar to what is observed in FIT2-deficient cells loaded with fatty acids. Our findings show that FIT2 acts as anacyl-CoA diphosphatase in vivo and is crucial for normal hepatocyte function and ER homeostasis in murine liver