7-Ketocholesterol Promotes Oxiapoptophagy in Bone Marrow Mesenchymal Stem Cell from Patients with Acute Myeloid Leukemia

FooDOxS: a database of oxidized sterols content in foods

Dietary oxidized sterols (DOxS) are cholesterol-like molecules known to exert pro-inflammatory, pro-oxidant, and pro-apoptotic effects, among others. We present the FooDOxS database, a comprehensive compilation of DOxS content in over 1680 food items from 120 publications across 25 countries, augmented by data generated by our group. This database reports DOxS content in foods classified under the NOVA and What We Eat in America (WWEIA) systems, allowing a comprehensive and statistically robust summary of DOxS content in foods. Notably, we evaluated the efficacy of using NOVA and WWEIA classifications in capturing DOxS variations across food categories. Our findings provide insights into the strengths and limitations of these classification systems, enhancing their utility for assessing dietary components. This research contributes to the understanding of DOxS in food processing and suggests refinements for classification systems, holding promise for improved food safety and public health assessments.

Influence of Human Bone Marrow Mesenchymal Stem Cells Secretome from Acute Myeloid Leukemia Patients on the Proliferation and Death of K562 and K562-Lucena Leukemia Cell Lineages

Leukemias are among the most prevalent types of cancer worldwide. Bone marrow mesenchymal stem cells (MSCs) participate in the development of a suitable niche for hematopoietic stem cells, and are involved in the development of diseases such as leukemias, to a yet unknown extent. Here we described the effect of secretome of bone marrow MSCs obtained from healthy donors and from patients with acute myeloid leukemia (AML) on leukemic cell lineages, sensitive (K562) or resistant (K562-Lucena) to chemotherapy drugs. Cell proliferation, viability and death were evaluated, together with cell cycle, cytokine production and gene expression of ABC transporters and cyclins. The secretome of healthy MSCs decreased proliferation and viability of both K562 and K562-Lucena cells; moreover, an increase in apoptosis and necrosis rates was observed, together with the activation of caspase 3/7, cell cycle arrest in G0/G1 phase and changes in expression of several ABC proteins and cyclins D1 and D2. These effects were not observed using the secretome of MSCs derived from AML patients. In conclusion, the secretome of healthy MSCs have the capacity to inhibit the development of leukemia cells, at least in the studied conditions. However, MSCs from AML patients seem to have lost this capacity, and could therefore contribute to the development of leukemia.

Targeting 7KCh-Induced Cell Death Response Mediated by p38, P2X7 and GSDME in Retinal Pigment Epithelium Cells with Sterculic Acid

Age-related macular degeneration (AMD) is the main cause of blindness in developed countries. AMD is characterized by the formation of drusen, which are lipidic deposits, between retinal pigment epithelium (RPE) and the choroid. One of the main molecules accumulated in drusen is 7-Ketocholesterol (7KCh), an oxidized-cholesterol derivative. It is known that 7KCh induces inflammatory and cytotoxic responses in different cell types and the study of its mechanism of action is interesting in order to understand the development of AMD. Sterculic acid (SA) counteracts 7KCh response in RPE cells and could represent an alternative to improve currently used AMD treatments, which are not efficient enough. In the present study, we determine that 7KCh induces a complex cell death signaling characterized by the activation of necrosis and an alternative pyroptosis mediated by P2X7, p38 and GSDME, a new mechanism not yet related to the response to 7KCh until now. On the other hand, SA treatment can successfully attenuate the activation of both necrosis and pyroptosis, highlighting its therapeutic potential for the treatment of AMD.

Cholesterol-autoxidation metabolites in host defense against infectious diseases

Cholesterol plays essential roles in biological processes, including cell membrane stability and myelin formation. Cholesterol can be metabolized to oxysterols by enzymatic or nonenzymatic ways. Nonenzymatic cholesterol metabolites, also called cholesterol-autoxidation metabolites, are formed dependent on the oxidation of reactive oxygen species (ROS) such as OH• or reactive nitrogen species, such as ONOO- . Cholesterol-autoxidation metabolites are abundantly produced in diseases such as inflammatory bowel disease and atherosclerosis, which are associated with oxidative stress. Recent studies have shown that cholesterol-autoxidation metabolites can further regulate the immune system. Here, we review the literature and summarize how cholesterol-autoxidation metabolites, such as 25-hydroxycholesterol (25-OHC), 7α/β-OHC, and 7-ketocholesterol, deal with the occurrence and development of infectious diseases through pattern recognition receptors, inflammasomes, ROS production, nuclear receptors, G-protein-coupled receptor 183, and lipid availability. In addition, we include the research regarding the roles of these metabolites in COVID-19 infection and discuss our viewpoints on the future research directions.

ATF5 Attenuates Apoptosis in Hippocampal Neurons with Seizures Evoked by Mg2+-Free Medium via Regulating Mitochondrial Unfolded Protein Response

The mitochondrial unfolded protein response (mtUPR)-a stress response pathway for maintaining protein homeostasis-is critical in seizures-induced neuronal injury. The activating transcription factor 5 (ATF5) regulates mtUPR; however, whether ATF5-regulated mtUPR has a role in neuronal injury in epilepsy remains uncertain. Here, we investigated the effects of ATF5-regulated mtUPR on neuronal injury in hippocampal neurons with seizures evoked by Mg²⁺-free medium. HSP60 and ClpP, key proteins of mtUPR, were upregulated, indicating mtUPR activation. ATF5 overexpression by lentiviral vector infection potentiated mtUPR, whereas ATF5 downregulation by lentiviral vector infection attenuated this response. Moreover, ATF5 overexpression elevated mitochondrial membrane potential and reduced reactive oxygen species (ROS) generation, suggesting that ATF5 overexpression protected mitochondrial homeostasis, while ATF5 downregulation had the opposite effect. ATF5 overexpression also reversed Bcl2 downregulation and Bax upregulation and attenuated seizures-induced neuronal apoptosis, while ATF5 downregulation aggravated the injury. Our study demonstrates that ATF5 attenuates seizures-induced neuronal injury, possibly by regulating mtUPR pathways, to prevent mitochondrial dysfunction.

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 [...].

7-Ketocholesterol Induces Oxiapoptophagy and Inhibits Osteogenic Differentiation in MC3T3-E1 Cells

7-Ketocholesterol (7KC) is one of the oxysterols produced by the auto-oxidation of cholesterol during the dysregulation of cholesterol metabolism which has been implicated in the pathological development of osteoporosis (OP). Oxiapoptophagy involving oxidative stress, autophagy, and apoptosis can be induced by 7KC. However, whether 7KC produces negative effects on MC3T3-E1 cells by stimulating oxiapoptophagy is still unclear. In the current study, 7KC was found to significantly decrease the cell viability of MC3T3-E1 cells in a concentration-dependent manner. In addition, 7KC decreased ALP staining and mineralization and down-regulated the protein expression of OPN and RUNX2, inhibiting osteogenic differentiation. 7KC significantly stimulated oxidation and induced autophagy and apoptosis in the cultured MC3T3-E1 cells. Pretreatment with the anti-oxidant acetylcysteine (NAC) could effectively decrease NOX4 and MDA production, enhance SOD activity, ameliorate the expression of autophagy-related factors, decrease apoptotic protein expression, and increase ALP, OPN, and RUNX2 expression, compromising 7KC-induced oxiapoptophagy and osteogenic differentiation inhibition in MC3T3-E1 cells. In summary, 7KC may induce oxiapoptophagy and inhibit osteogenic differentiation in the pathological development of OP.

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

7α,25-dihydroxycholesterol (7α,25-DHC) is an oxysterol synthesized from 25-hydroxycholesterol by cytochrome P450 family 7 subfamily B member 1 (CYP7B1) and is a monooxygenase (oxysterol-7α-hydroxylase) expressed under inflammatory conditions in various cell types. In this study, we verified that 7α,25-DHC-induced oxiapoptophagy is mediated by apoptosis, oxidative stress, and autophagy in L929 mouse fibroblasts. MTT assays and live/dead cell staining revealed that cytotoxicity was increased by 7α,25-DHC in L929 cells. Consequentially, cells with condensed chromatin and altered morphology were enhanced in L929 cells incubated with 7α,25-DHC for 48 h. Furthermore, apoptotic population was increased by 7α,25-DHC exposure through the cascade activation of caspase-9, caspase-3, and poly (ADP-ribose) polymerase in the intrinsic pathway of apoptosis in these cells. 7α,25-DHC upregulated reactive oxygen species (ROS) in L929 cells. Expression of autophagy biomarkers, including beclin-1 and LC3, was significantly increased by 7α,25-DHC treatment in L929 cells. 7α,25-DHC inhibits the phosphorylation of Akt associated with autophagy and increases p53 expression in L929 cells. In addition, inhibition of G-protein-coupled receptor 183 (GPR183), a receptor of 7α,25-DHC, using GPR183 specific antagonist NIBR189 suppressed 7α,25-DHC-induced apoptosis, ROS production, and autophagy in L929 cells. Collectively, GPR183 regulates 7α,25-DHC-induced oxiapoptophagy in L929 cells.

New Function of Cholesterol Oxidation Products Involved in Osteoporosis Pathogenesis

Osteoporosis (OP) is a systemic bone disease characterized by decreased bone strength, microarchitectural changes in bone tissues, and increased risk of fracture. Its occurrence is closely related to various factors such as aging, genetic factors, living habits, and nutritional deficiencies as well as the disturbance of bone homeostasis. The dysregulation of bone metabolism is regarded as one of the key influencing factors causing OP. Cholesterol oxidation products (COPs) are important compounds in the maintenance of bone metabolic homeostasis by participating in several important biological processes such as the differentiation of mesenchymal stem cells, bone formation in osteoblasts, and bone resorption in osteoclasts. The effects of specific COPs on mesenchymal stem cells are mainly manifested by promoting osteoblast genesis and inhibiting adipocyte genesis. This review aims to elucidate the biological roles of COPs in OP development, starting from the molecular mechanisms of OP, pointing out opportunities and challenges in current research, and providing new ideas and perspectives for further studies of OP pathogenesis.

Oxysterols in the Immune Response to Bacterial and Viral Infections

Oxidized cholesterols, the so-called oxysterols, are widely known to regulate cholesterol homeostasis. However, more recently oxysterols have emerged as important lipid mediators in the response to both bacterial and viral infections. This review summarizes our current knowledge of selected oxysterols and their receptors in the control of intracellular bacterial growth as well as viral entry into the host cell and viral replication. Lastly, we briefly discuss the potential of oxysterols and their receptors as drug targets for infectious and inflammatory diseases.

Can oxysterols work in anti-glioblastoma therapy? Model studies complemented with biological experiments

Despite the progress made in recent years in the field of oncology, the results of glioblastoma treatment remain unsatisfactory. In this paper, cholesterol derivatives - oxysterols - have been investigated in the context of their anti-cancer activity. First, the influence of three oxysterols (7-K, 7β-OH and 25-OH), differing in their chemical structure, on the properties of a model membrane imitating glioblastoma multiforme (GBM) cells was investigated. For this purpose, the Langmuir monolayer technique was applied. The obtained results clearly show that oxysterols modify the structure of the membrane by its stiffening, with the 7-K effect being the most pronounced. Next, the influence of 7-K on the nanomechanical properties of glioblastoma cells (U-251 line) was verified with AFM. It has been shown that 7-K has a dose-dependent cytotoxic effect on glioblastoma cells leading to the induction of apoptosis as confirmed by viability tests. Interestingly, significant changes in membrane structure, characteristic for phospholipidosis, has also been observed. Based on our results we believe that oxysterol-induced apoptosis and phospholipidosis are related and may share common signaling pathways. Dysregulation of lipids in phospholipidosis inhibit cell proliferation and may play key roles in the induction of apoptosis by oxysterols. Moreover, anticancer activity of these compounds may be related to the immobilization of cancer cells as a result of stiffening effect caused by oxysterols. Therefore, we believe that oxysterols are good candidates as new therapeutic molecules as an alternative to the aggressive treatment of GBM currently in use.

Autophagy-lysosome dysfunction is involved in gastric ischemia-reperfusion injury by promoting microglial activation in the paraventricular nucleus

The hypothalamic paraventricular nucleus (PVN) is a specific center in the brain that regulates gastric mucosal injury following gastric ischemia-reperfusion (GI-R) injury. This study aimed to investigate whether autophagy-lysosome dysfunction in the PVN tissues of GI-R rats is involved in the gastric injury, and the underlying molecular mechanisms. The rat model of GI-R was established by clamping the celiac artery for 30 min and reperfusion for different hours (1, 3, and 6 h). The gastric injury was evaluated by hematoxylin and eosin staining of the stomach and the gastric mucosal index. The autophagy-lysosome dysfunction in the PVN was evaluated by the protein levels of LC3 II and Beclin-1 (markers for autophagosome activity) and the activity of acid phosphatase (a representative lysosomal enzyme). Immunohistochemical staining of ionized calcium-binding adaptor molecule 1 in the PVN was performed to evaluate microglial activation. Reactive oxygen species (ROS) content and phosphorylated γ-aminobutyric acid B receptor (p-GABA_B R) expression in the PVN were also examined. The results revealed that, in GI-R rats, the shorter the reperfusion duration, the more severe the gastric mucosal damage. The autophagy-lysosome dysfunction exhibited by GI-R rats further enhanced microglial activation, ROS production, p-GABA_B R expression, and gastric injury. In addition, activating microglial cells increased ROS production, p-GABA_B R expression, and gastric injury in GI-R rats, while inhibiting microglial activation resulted in the opposite results. Taken together, autophagy-lysosome dysfunction induced by GI-R aggravated the gastric injury by inducing microglia activation.

Impact of Oxysterols on Cell Death, Proliferation, and Differentiation Induction: Current Status

Oxysterols are oxidized derivatives of cholesterol produced by enzymatic activity or non-enzymatic pathways (auto-oxidation). The oxidation processes lead to the synthesis of about 60 different oxysterols. Several oxysterols have physiological, pathophysiological, and pharmacological activities. The effects of oxysterols on cell death processes, especially apoptosis, autophagy, necrosis, and oxiapoptophagy, as well as their action on cell proliferation, are reviewed here. These effects, also observed in several cancer cell lines, could potentially be useful in cancer treatment. The effects of oxysterols on cell differentiation are also described. Among them, the properties of stimulating the osteogenic differentiation of mesenchymal stem cells while inhibiting adipogenic differentiation may be useful in regenerative medicine.

Cell signaling pathways as molecular targets to eliminate AML stem cells

Acute myeloid leukemia (AML) remains the most lethal of leukemias and a small population of cells called leukemic stem cells (LSCs) has been associated with disease relapses. Some cell signaling pathways play an important role in AML survival, proliferation and self-renewal properties and are abnormally activated or suppressed in LSCs. This includes the NF-κB, Wnt/β-catenin, Hedgehog, Notch, EGFR, JAK/STAT, PI3K/AKT/mTOR, TGF/SMAD and PPAR pathways. This review aimed to discuss these pathways as molecular targets for eliminating AML LSCs. Herein, inhibitors/activators of these pathways were summarized as a potential new anti-AML therapy capable of eliminating LSCs to guide future researches. The clinical use of cell signaling pathways data can be useful to enhance the anti-AML therapy.

Oxysterols and mesenchymal stem cell biology

Mesenchymal stem cells have the ability to differentiate into several cell types when exposed to determined substances, including oxysterols. Oxysterols are cholesterol products derived from its auto-oxidation by reactive species or from enzymatic action. They are present in the body in low quantities under physiological conditions and exhibit several physiological and pharmacological actions according to both the types of oxysterol and tissue. Some of them are cytotoxic while others have been shown to promote cell differentiation through the action on several different receptors, such as nuclear LXR receptors and Smoothened receptor ligands. Here, we review the main pathways by which oxysterols have been associated with cell differentiation and death of mesenchymal stem cells.

Oxidative phosphorylation enhances the leukemogenic capacity and resistance to chemotherapy of B cell acute lymphoblastic leukemia

How metabolic status controls the fates of different types of leukemia cells remains elusive. Using a SoNar-transgenic mouse line, we demonstrated that B cell acute lymphoblastic leukemia (B-ALL) cells had a preference in using oxidative phosphorylation. B-ALL cells with a low SoNar ratio (SoNar-low) had enhanced mitochondrial respiration capacity, mainly resided in the vascular niche, and were enriched with more functional leukemia-initiating cells than that of SoNar-high cells in a murine B-ALL model. The SoNar-low cells were more resistant to cytosine arabinoside (Ara-C) treatment. cyclic adenosine 3',5'-monophosphate response element-binding protein transactivated pyruvate dehydrogenase complex component X and cytidine deaminase to maintain the oxidative phosphorylation level and Ara-C-induced resistance. SoNar-low human primary B-ALL cells also had a preference for oxidative phosphorylation. Suppressing oxidative phosphorylation with several drugs sufficiently attenuated Ara-C-induced resistance. Our study provides a unique angle for understanding the potential connections between metabolism and B-ALL cell fates.

Small-sized extracellular vesicles (EVs) derived from acute myeloid leukemia bone marrow mesenchymal stem cells transfer miR-26a-5p to promote acute myeloid leukemia cell proliferation, migration, and invasion

Bone marrow mesenchymal stem cells (BMSCs) in acute myeloid leukemia (AML) microenvironment undergo modification that includes expression of contents in the small-sized extracellular vesicles (EVs) they secrete. This study aims to investigate whether small-sized EVs from BMSCs of AML patients regulate AML progression by modifying the expression of miR-26a-5p. Small-sized EVs from BMSCs of AML patients (AML-BMSC-EVs) or healthy controls (HC-BMSC-EVs) were isolated by ultra-centrifugation and administered to AML cells (OCI/AML-2 and THP-1). Cell proliferation, migration, and invasion were evaluated by CCK-8 assay, Transwell migration and invasion assays, respectively. Compared with HC-BMSC-EVs, AML-BMSC-EVs contained higher expression of miR-26a-5p and promoted AML cell proliferation, migration, and invasion. Inhibition of miR-26a-5p expression in AML-BMSC-EVs could abrogate the promoting effects of AML-BMSC-EVs on AML cell proliferation, migration, and invasion. Furthermore, GSK3β was a direct target of miR-26a-5p. Moreover, AML-BMSC-EVs inhibited GSK3β expression and activated Wnt/β-catenin signaling in AML cells. Additionally, GSK3β overexpression in THP-1 cells counteracted the promoting effects of AML-BMSCs-EVs on THP-1 cell proliferation, migration, and invasion. AML-BMSC-EVs promoted AML progression by transferring miR-26a-5p to AML cells and subsequently activating the Wnt/β-catenin pathway.

Paraoxonase Role in Human Neurodegenerative Diseases

The human body has biological redox systems capable of preventing or mitigating the damage caused by increased oxidative stress throughout life. One of them are the paraoxonase (PON) enzymes. The PONs genetic cluster is made up of three members (PON1, PON2, PON3) that share a structural homology, located adjacent to chromosome seven. The most studied enzyme is PON1, which is associated with high density lipoprotein (HDL), having paraoxonase, arylesterase and lactonase activities. Due to these characteristics, the enzyme PON1 has been associated with the development of neurodegenerative diseases. Here we update the knowledge about the association of PON enzymes and their polymorphisms and the development of multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD) and Parkinson's disease (PD).

Ferroptosis Mechanisms Involved in Neurodegenerative Diseases

Ferroptosis is a type of cell death that was described less than a decade ago. It is caused by the excess of free intracellular iron that leads to lipid (hydro) peroxidation. Iron is essential as a redox metal in several physiological functions. The brain is one of the organs known to be affected by iron homeostatic balance disruption. Since the 1960s, increased concentration of iron in the central nervous system has been associated with oxidative stress, oxidation of proteins and lipids, and cell death. Here, we review the main mechanisms involved in the process of ferroptosis such as lipid peroxidation, glutathione peroxidase 4 enzyme activity, and iron metabolism. Moreover, the association of ferroptosis with the pathophysiology of some neurodegenerative diseases, namely Alzheimer’s, Parkinson’s, and Huntington’s diseases, has also been addressed.

Prevention by Dietary Polyphenols (Resveratrol, Quercetin, Apigenin) Against 7-Ketocholesterol-Induced Oxiapoptophagy in Neuronal N2a Cells: Potential Interest for the Treatment of Neurodegenerative and Age-Related Diseases

The Mediterranean diet is associated with health benefits due to bioactive compounds such as polyphenols. The biological activities of three polyphenols (quercetin (QCT), resveratrol (RSV), apigenin (API)) were evaluated in mouse neuronal N2a cells in the presence of 7-ketocholesterol (7KC), a major cholesterol oxidation product increased in patients with age-related diseases, including neurodegenerative disorders. In N2a cells, 7KC (50 µM; 48 h) induces cytotoxic effects characterized by an induction of cell death. When associated with RSV, QCT and API (3.125; 6.25 µM), 7KC-induced toxicity was reduced. The ability of QCT, RSV and API to prevent 7KC-induced oxidative stress was characterized by a decrease in reactive oxygen species (ROS) production in whole cells and at the mitochondrial level; by an attenuation of the increase in the level and activity of catalase; by attenuating the decrease in the expression, level and activity of glutathione peroxidase 1 (GPx1); by normalizing the expression, level and activity of superoxide dismutases 1 and 2 (SOD1, SOD2); and by reducing the decrease in the expression of nuclear erythroid 2-like factor 2 (Nrf2) which regulates antioxidant genes. QCT, RSV and API also prevented mitochondrial dysfunction in 7KC-treated cells by counteracting the loss of mitochondrial membrane potential (ΨΔm) and attenuating the decreased gene expression and/or protein level of AMP-activated protein kinase α (AMPKα), sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) implicated in mitochondrial biogenesis. At the peroxisomal level, QCT, RSV and API prevented the impact of 7KC by counteracting the decrease in ATP binding cassette subfamily D member (ABCD)3 (a peroxisomal mass marker) at the protein and mRNA levels, as well as the decreased expresssion of genes associated with peroxisomal biogenesis (Pex13, Pex14) and peroxisomal β-oxidation (Abcd1, Acox1, Mfp2, Thiolase A). The 7KC-induced decrease in ABCD1 and multifunctional enzyme type 2 (MFP2), two proteins involved in peroxisomal β-oxidation, was also attenuated by RSV, QCT and API. 7KC-induced cell death, which has characteristics of apoptosis (cells with fragmented and/or condensed nuclei; cleaved caspase-3; Poly(ADP-ribose) polymerase (PARP) fragmentation) and autophagy (cells with monodansyl cadaverine positive vacuoles; activation of microtubule associated protein 1 light chain 3–I (LC3-I) to LC3-II, was also strongly attenuated by RSV, QCT and API. Thus, in N2a cells, 7KC induces a mode of cell death by oxiapoptophagy, including criteria of OXIdative stress, APOPTOsis and autoPHAGY, associated with mitochondrial and peroxisomal dysfunction, which is counteracted by RSV, QCT, and API reinforcing the interest for these polyphenols in prevention of diseases associated with increased 7KC levels.

Mutagenicity of 7-ketocholesterol in CHO cells: The role of lipid peroxidation

As an important cholesterol oxide, 7-ketocholesterol plays a deleterious role in the occurrence of cancer. Although the fact had been proved that 7-ketocholesterol could induce several biological phenomena, including apoptosis, DNA damage, et al., this issue whether 7-ketocholesterol led to mutagenesis in mammalian cells remains largely unexplored. Here, we investigated the major role of lipid peroxidation in the genotoxic response to 7-ketocholesterol in chinese hamster ovary (CHO) cells. The results showed that 7-ketocholesterol induced gene mutation and DNA double-strand breaks (DSBs) in concentration- and time-dependent manner. After CHO cells were treated with 25 μM 7-ketocholesterol for 48 h, the mutation frequency at hprt gene loci and the level of γ-H2AX protein were both significantly increased. Exposure to 7-ketocholesterol resulted in a concentration-dependent increase in the apoptotic rate and the protein expression of cleaved caspase-3 and -7 in CHO cells. Moreover, a significant increase of superoxide dismutase (SOD) activity and content of malondialdehyde (MDA) was also observed. Using a inhibitor of lipid peroxidation (butylated hydroxytoluene), it was found to remarkably inhibit the genotoxicity and MDA levels caused by 7-ketocholesterol. These findings indicated that lipid peroxidation was involved in the mutagenic process of 7-ketocholesterol in CHO cells.

7-Ketocholesterol in disease and aging

7-Ketocholesterol (7KC) is a toxic oxysterol that is associated with many diseases and disabilities of aging, as well as several orphan diseases. 7KC is the most common product of a reaction between cholesterol and oxygen radicals and is the most concentrated oxysterol found in the blood and arterial plaques of coronary artery disease patients as well as various other disease tissues and cell types. Unlike cholesterol, 7KC consistently shows cytotoxicity to cells and its physiological function in humans or other complex organisms is unknown. Oxysterols, particularly 7KC, have also been shown to diffuse through membranes where they affect receptor and enzymatic function. Here, we will explore the known and proposed mechanisms of pathologies that are associated with 7KC, as well speculate about the future of 7KC as a diagnostic and therapeutic target in medicine.