GPR183 Regulates 7α,25-Dihydroxycholesterol-Induced Oxiapoptophagy in L929 Mouse Fibroblast Cell

Oxysterols, age-related-diseases and nutritherapy: Focus on 7-ketocholesterol and 7β-hydroxycholesterol

Age-related diseases are often associated with a disruption of RedOx balance that can lead to lipid peroxidation with the formation of oxysterols, especially those oxidized on carbon-7: 7-ketocholesterol (also known as 7-oxo-cholesterol) and 7β-hydroxycholesterol. Like cholesterol, these oxysterols have 27 carbons, they are composed of a sterane nucleus and have a hydroxyl function in position 3. The oxysterols 7-ketocholesterol and 7β-hydroxycholesterol are mainly formed by cholesterol autoxidation and are biomarkers of oxidative stress. These two oxysterols are frequently found at increased levels in the biological fluids (plasma, cerebrospinal fluid), tissues and/or organs (arterial wall, retina, brain) of patients with age-related diseases, especially cardiovascular diseases, neurodegenerative diseases (mainly Alzheimer's disease), ocular diseases (cataract, age-related macular degeneration), and sarcopenia. Depending on the cell type considered, 7-ketocholesterol and 7β-hydroxycholesterol induce either caspase- dependent or -independent types of cell death associated with mitochondrial and peroxisomal dysfunctions, autophagy and oxidative stress. The caspase dependent type of cell death associated with oxidative stress and autophagy is defined as oxiapoptophagy. These two oxysterols are also inducers of inflammation. These biological features associated with the toxicity of 7-ketocholesterol, and 7β-hydroxycholesterol are often observed in patients with age-related diseases, suggesting an involvement of these oxysterols in the pathophysiology of these disorders. The cytotoxic effects of 7-ketocholesterol and 7β-hydroxycholesterol are counteracted on different cell models by representative nutrients of the Mediterranean diet: ω3 and ω9 fatty acids, polyphenols, and tocopherols. There are also evidences, mainly in cardiovascular diseases, of the benefits of α-tocopherol and phenolic compounds. These in vitro and in vivo observations on 7-ketocholesterol and 7β-hydroxycholesterol, which are frequently increased in age-related diseases, reinforce the interest of nutritherapeutic treatments to prevent and/or cure age-related diseases currently without effective therapies.

Exploring G Protein-Coupled Receptors in Hematological Cancers

Hematological cancers, such as lymphomas and leukemias, pose significant challenges in oncology, necessitating a deeper understanding of their molecular landscape to enhance therapeutic strategies. This article critically examines and discusses recent research on the roles of G protein-coupled receptors (GPCRs) in myeloma, lymphomas, and leukemias with a particular focus on pediatric acute lymphoblastic (lymphocytic) leukemia (ALL). By utilizing RNA sequencing (RNA-seq), we analyzed GPCR expression patterns in pediatric ALL samples (aged 3-12 years old), with a further focus on Class A orphan GPCRs. Our analysis revealed distinct GPCR expression profiles in pediatric ALL, identifying several candidates with aberrant upregulated expression compared with healthy counterparts. Among these GPCRs, GPR85, GPR65, and GPR183 have varying numbers of studies in the field of hematological cancers and pediatric ALL. Furthermore, we explored missense mutations of pediatric ALL in relation to the RNA gene expression findings, providing insights into the genetic underpinnings of this disease. By integrating both RNA-seq and missense mutation data, this article aims to provide an insightful and broader perspective on the potential correlations between specific GPCR and their roles in pediatric ALL.

Synthesis, Evaluation and Docking Studies of Disubstituted N-Heterocyclic Derivatives as Anticancer Agents

Cancer is a chronic disease reported with alarming rates of mortalities every year. Herein, we reported the synthesis of nitrogen based novel heterocyclic disubstituted derivatives and evaluated them against L929 and A549 cell lines using MTT assay. Among all, 6a2 and 6c1 were significantly active against L929 with IC50 value of 2.61±9.58 and 2.64±8.97 μg/mL respectively. Compounds 6a2 and 6c1 were also active against A549 with IC50 value of 2.36±9.20 and 2.43±6.28 μg/mL respectively and were found to be more potent than the standard drug Doxorubicin. A molecular docking study of the active compounds was also done against EGFR, conferring good binding affinity and binding interactions. Further biological investigations may provide valuable insights towards exploring the therapeutic potential of the active compounds in future.

Cytoprotective effects of α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol on 7-ketocholesterol - Induced oxiapoptophagy: Major roles of PI3-K / PDK-1 / Akt signaling pathway and glutathione peroxidase activity in cell rescue

On murine N2a cells, 7-ketocholesterol induced an oxiapotophagic mode of cell death characterized by oxidative stress (reactive oxygen species overproduction on whole cells and at the mitochondrial level; lipid peroxidation), apoptosis induction (caspase-9, -3 and -7 cleavage, PARP degradation) and autophagy (increased ratio LC3-II / LC3-I). Oxidative stress was strongly attenuated by diphenyleneiodonium chloride which inhibits NAD(P)H oxidase. Mitochondrial and peroxisomal morphological and functional changes were also observed. Down regulation of PDK1 / Akt signaling pathways as well as of GSK3 / Mcl-1 and Nrf2 pathways were simultaneously observed in 7-ketocholesterol-induced oxiapoptophagy. These events were prevented by α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol. The inhibition of the cytoprotection by LY-294002, a PI3-K inhibitor, demonstrated an essential role of PI3-K in cell rescue. The rupture of oxidative stress in 7-ketocholesterol-induced oxiapoptophagy was also associated with important modifications of glutathione peroxidase, superoxide dismutase and catalase activities as well as of glutathione peroxidase-1, superoxide dismutase-1 and catalase level and expression. These events were also counteracted by α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol. The inhibition of the cytoprotection by mercaptosuccinic acid, a glutathione peroxidase inhibitor, showed an essential role of this enzyme in cell rescue. Altogether, our data support that the reactivation of PI3-K and glutathione peroxidase activities by α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol are essential to prevent 7KC-induced oxiapoptophagy.

25-Hydroxycholesterol in health and diseases

Cholesterol is an essential structural component of all membranes of mammalian cells where it plays a fundamental role not only in cellular architecture, but also, for example, in signaling pathway transduction, endocytosis process, receptor functioning and recycling, or cytoskeleton remodeling. Consequently, intracellular cholesterol concentrations are tightly regulated by complex processes, including cholesterol synthesis, uptake from circulating lipoproteins, lipid transfer to these lipoproteins, esterification, and metabolization into oxysterols that are intermediates for bile acids. Oxysterols have been considered for long time as sterol waste products, but a large body of evidence has clearly demonstrated that they play key roles in central nervous system functioning, immune cell response, cell death, or migration and are involved in age-related diseases, cancers, autoimmunity, or neurological disorders. Among all the existing oxysterols, this review summarizes basic as well as recent knowledge on 25-hydroxycholesterol which is mainly produced during inflammatory or infectious situations and that in turn contributes to immune response, central nervous system disorders, atherosclerosis, macular degeneration, or cancer development. Effects of its metabolite 7α,25-dihydroxycholesterol are also presented and discussed.

Stearyl palmitate a multi-target inhibitor against breast cancer: in-silico, in-vitro & in-vivo approach

Multi-target inhibitors are currently trending in the pharmaceutical research, as they possess increased efficacy and reduced toxicity. In this study multi-target inhibitors for breast cancer are explored from a curated list of natural products, i.e. 4,670 phytochemicals belonging to 360 medicinal plants. In-silico screening of phytochemicals using SeeSAR and AutoDock Vina resulted in identification of Stearyl Palmitate as a potential drug molecule that inhibits three drug targets, i.e. HER-2, MEK-1 and PARP-1 proteins. Molecular Dynamics Simulation for 100 ns each for these three protein-ligand complexes using Desmond, Maestro platform also confirmed the prediction of multi-target inhibition by Stearyl Palmitate. Further in-vitro MTT assay demonstrated that Stearyl Palmitate has a significant IC50 value of 40 µM against MCF-7 cells and >1000 µM against L929 cells. This confirmed that Stearyl Palmitate is having selective cytotoxicity towards breast cancer cells in comparison to non-cancerous cells. Fluorescence staining and flow cytometry analysis confirmed that, Stearyl Palmitate is inducing apoptosis in MCF-7 cells at IC50 concentration. Finally, in-vivo efficacy and toxicity studies were performed using zebrafishes (Danio rerio). It was observed that the fishes treated with IC50 concentration of Stearyl Palmitate demonstrated 2x folds reduction in tumour size, while double dose resulted in 4x folds reduction in tumour size. Stearyl Palmitate did not demonstrate any toxicity or side effects in the zebrafishes. It is concluded that, Stearyl Palmitate, a phytochemical reported to be present in Althea officinalis is a potential anti-breast cancer agent, with ability to inhibit multiple targets such as HER-2, MEK-1 and PARP-2 proteins.Communicated by Ramaswamy H. Sarma.

Oxiapoptophagy in Age-Related Diseases. Comment on Ouyang et al. 7-Ketocholesterol Induces Oxiapoptophagy and Inhibits Osteogenic Differentiation in MC3T3-E1 Cells. Cells 2022, 11, 2882

Due to the increase in life span and life expectancy, which can, however, be more or less pronounced depending on the economic, social and cultural context [...].