Proteomic analysis identifies deregulated metabolic and oxidative-associated proteins in Italian intrahepatic cholangiocarcinoma patients

Disturbance of mitochondrial functions caused by N-acetylglutamate and N-acetylmethionine in brain of adolescent rats: Potential relevance in aminoacylase 1 deficiency

Aminoacylase 1 (ACY1) deficiency is a rare genetic disorder that affects the breakdown of short-chain aliphatic N-acetylated amino acids, leading to the accumulation of these amino acid derivatives in the urine of patients. Some of the affected individuals have presented with heterogeneous neurological symptoms such as psychomotor delay, seizures, and intellectual disability. Considering that the pathological mechanisms of brain damage in this disorder remain mostly unknown, here we investigated whether major metabolites accumulating in ACY1 deficiency, namely N-acetylglutamate (NAG) and N-acetylmethionine (NAM), could be toxic to the brain by examining their in vitro effects on important mitochondrial properties. We assessed the effects of NAG and NAM on membrane potential, swelling, reducing equivalents, and Ca2+ retention capacity in purified mitochondrial preparations obtained from the brain of adolescent rats. NAG and NAM decreased mitochondrial membrane potential, reducing equivalents, and calcium retention capacity, and induced swelling in Ca2+-loaded brain mitochondria supported by glutamate plus malate. Notably, these changes were completely prevented by the classical inhibitors of mitochondrial permeability transition (MPT) pore cyclosporin A plus ADP and by ruthenium red, implying the participation of MPT and Ca2+ in these effects. Our findings suggest that NAG- and NAM-induced disruption of mitochondrial functions involving MPT may represent relevant mechanisms of neuropathology in ACY1 deficiency.

Acyl coenzyme A binding protein (ACBP): An aging- and disease-relevant "autophagy checkpoint"

Acyl coenzyme A binding protein (ACBP), also known as diazepam-binding inhibitor (DBI), is a phylogenetically ancient protein present in some eubacteria and the entire eukaryotic radiation. In several eukaryotic phyla, ACBP/DBI transcends its intracellular function in fatty acid metabolism because it can be released into the extracellular space. This ACBP/DBI secretion usually occurs in response to nutrient scarcity through an autophagy-dependent pathway. ACBP/DBI and its peptide fragments then act on a range of distinct receptors that diverge among phyla, namely metabotropic G protein-coupled receptor in yeast (and likely in the mammalian central nervous system), a histidine receptor kinase in slime molds, and ionotropic gamma-aminobutyric acid (GABA)A receptors in mammals. Genetic or antibody-mediated inhibition of ACBP/DBI orthologs interferes with nutrient stress-induced adaptations such as sporulation or increased food intake in multiple species, as it enhances lifespan or healthspan in yeast, plant leaves, nematodes, and multiple mouse models. These lifespan and healthspan-extending effects of ACBP/DBI suppression are coupled to the induction of autophagy. Altogether, it appears that neutralization of extracellular ACBP/DBI results in "autophagy checkpoint inhibition" to unleash the anti-aging potential of autophagy. Of note, in humans, ACBP/DBI levels increase in various tissues, as well as in the plasma, in the context of aging, obesity, uncontrolled infection or cardiovascular, inflammatory, neurodegenerative, and malignant diseases.

Unraveling the actin cytoskeleton in the malignant transformation of cholangiocyte biology

Correct actin cytoskeleton organization is vital in the liver organ homeostasis and disease control. Rearrangements of the actin cytoskeleton may play a vital role in the bile duct cells cholangiocytes. An abnormal actin network leads to aberrant cell morphology, deregulated signaling networks and ultimately triggering the development of cholangiocarcinoma (CCA) and paving the route for cancer cell dissemination (metastasis). In this review, we will outline alterations of the actin cytoskeleton and the potential role of this dynamic network in initiating CCA, as well as regulating the course of this malignancy. Actin rearrangements not only occur because of signaling pathways, but also regulate and modify cellular signaling. This emphasizes the importance of the actin cytoskeleton itself as cause for aberrant signaling and in promoting tumorigenic phenotypes. We will highlight the impact of aberrant signaling networks on the actin cytoskeleton and its rearrangement as potential cause for CCA. Often, these exact mechanisms in CCA are limited understood and still must be elucidated. Indeed, focusing future research on how actin affects and regulates other signaling pathways may provide more insights into the mechanisms of CCA development, progression, and metastasis. Moreover, manipulation of the actin cytoskeleton organization highlights the potential for a novel therapeutic area.

Antioxidant Effect of Chrysanthemum morifolium (Chuju) Extract on H2O2-Treated L-O2 Cells as Revealed by LC/MS-Based Metabolic Profiling

Chrysanthemum has a long history of being used to attenuate various oxidative stress-related discomforts and diseases; however, its mechanisms remain unclear. In this study, the antioxidant effect of chrysanthemum aqueous extract was investigated, and the potential mechanisms were explored via a metabolomics study. Chrysanthemum extract could significantly inhibit hydrogen peroxide (H₂O₂)-mediated cell death in L-O2 hepatocytes. Propidium iodide staining and annexin V-PI dual staining revealed that the antioxidant effect of chrysanthemum extract was related to the relief of cell cycle arrest and inhibition of non-apoptotic cell damage. The activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were also upregulated by chrysanthemum extract. Through metabolomics studies, it was found that chrysanthemum extract mainly targeted the arginine synthesis pathway and purine metabolism pathway, in which antioxidation-related endogenous substrates including L-arginosuccinate, citrulline and inositol monophosphate were significantly upregulated by chrysanthemum extract. These results indicated that chrysanthemum extract can antagonize oxidative stress through multiple pathways and have potential therapeutic applications.