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Staurenghi E, Leoni V, Lo Iacono M, Sottero B, Testa G, Giannelli S, Leonarduzzi G, Gamba P. ApoE3 vs. ApoE4 Astrocytes: A Detailed Analysis Provides New Insights into Differences in Cholesterol Homeostasis. Antioxidants (Basel) 2022; 11:2168. [PMID: 36358540 PMCID: PMC9686673 DOI: 10.3390/antiox11112168] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 10/28/2022] [Accepted: 10/29/2022] [Indexed: 07/30/2023] Open
Abstract
The strongest genetic risk factor for sporadic Alzheimer's disease (AD) is the presence of the ε4 allele of the apolipoprotein E (ApoE) gene, the major apolipoprotein involved in brain cholesterol homeostasis. Being astrocytes the main producers of cholesterol and ApoE in the brain, we investigated the impact of the ApoE genotype on astrocyte cholesterol homeostasis. Two mouse astrocytic cell lines expressing the human ApoE3 or ApoE4 isoform were employed. Gas chromatography-mass spectrometry (GC-MS) analysis pointed out that the levels of total cholesterol, cholesterol precursors, and various oxysterols are altered in ApoE4 astrocytes. Moreover, the gene expression analysis of more than 40 lipid-related genes by qRT-PCR showed that certain genes are up-regulated (e.g., CYP27A1) and others down-regulated (e.g., PPARγ, LXRα) in ApoE4, compared to ApoE3 astrocytes. Beyond confirming the significant reduction in the levels of PPARγ, a key transcription factor involved in the maintenance of lipid homeostasis, Western blotting showed that both intracellular and secreted ApoE levels are altered in ApoE4 astrocytes, as well as the levels of receptors and transporters involved in lipid uptake/efflux (ABCA1, LDLR, LRP1, and ApoER2). Data showed that the ApoE genotype clearly affects astrocytic cholesterol homeostasis; however, further investigation is needed to clarify the mechanisms underlying these differences and the consequences on neighboring cells. Indeed, drug development aimed at restoring cholesterol homeostasis could be a potential strategy to counteract AD.
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Affiliation(s)
- Erica Staurenghi
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, 10043 Turin, Italy
| | - Valerio Leoni
- Laboratory of Clinical Biochemistry, Hospital Pius XI of Desio, ASST-Brianza, University of Milano-Bicocca, 20126 Monza, Italy
- Department of Medicine and Surgery, University of Milano-Bicocca, 20126 Monza, Italy
| | - Marco Lo Iacono
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, 10043 Turin, Italy
| | - Barbara Sottero
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, 10043 Turin, Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, 10043 Turin, Italy
| | - Serena Giannelli
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, 10043 Turin, Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, 10043 Turin, Italy
| | - Paola Gamba
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, 10043 Turin, Italy
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Sottero B, Testa G, Gamba P, Staurenghi E, Giannelli S, Leonarduzzi G. Macrophage polarization by potential nutraceutical compounds: A strategic approach to counteract inflammation in atherosclerosis. Free Radic Biol Med 2022; 181:251-269. [PMID: 35158030 DOI: 10.1016/j.freeradbiomed.2022.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/27/2022] [Accepted: 02/09/2022] [Indexed: 12/13/2022]
Abstract
Chronic inflammation represents a main event in the onset and progression of atherosclerosis and is closely associated with oxidative stress in a sort of vicious circle that amplifies and sustains all stages of the disease. Key players of atherosclerosis are monocytes/macrophages. According to their pro- or anti-inflammatory phenotype and biological functions, lesional macrophages can release various mediators and enzymes, which in turn contribute to plaque progression and destabilization or, alternatively, lead to its resolution. Among the factors connected to atherosclerotic disease, lipid species carried by low density lipoproteins and pro-oxidant stimuli strongly promote inflammatory events in the vasculature, also by modulating the macrophage phenotyping. Therapies specifically aimed to balance macrophage inflammatory state are increasingly considered as powerful tools to counteract plaque formation and destabilization. In this connection, several molecules of natural origin have been recognized to be active mediators of diverse metabolic and signaling pathways regulating lipid homeostasis, redox state, and inflammation; they are, thus, considered as promising candidates to modulate macrophage responsiveness to pro-atherogenic stimuli. The current knowledge of the capability of nutraceuticals to target macrophage polarization and to counteract atherosclerotic lesion progression, based mainly on in vitro investigation, is summarized in the present review.
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Affiliation(s)
- Barbara Sottero
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Paola Gamba
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Erica Staurenghi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Serena Giannelli
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy.
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Staurenghi E, Giannelli S, Testa G, Sottero B, Leonarduzzi G, Gamba P. Cholesterol Dysmetabolism in Alzheimer's Disease: A Starring Role for Astrocytes? Antioxidants (Basel) 2021; 10:antiox10121890. [PMID: 34943002 PMCID: PMC8750262 DOI: 10.3390/antiox10121890] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 01/19/2023] Open
Abstract
In recent decades, the impairment of cholesterol metabolism in the pathogenesis of Alzheimer’s disease (AD) has been intensively investigated, and it has been recognized to affect amyloid β (Aβ) production and clearance, tau phosphorylation, neuroinflammation and degeneration. In particular, the key role of cholesterol oxidation products, named oxysterols, has emerged. Brain cholesterol metabolism is independent from that of peripheral tissues and it must be preserved in order to guarantee cerebral functions. Among the cells that help maintain brain cholesterol homeostasis, astrocytes play a starring role since they deliver de novo synthesized cholesterol to neurons. In addition, other physiological roles of astrocytes are to modulate synaptic transmission and plasticity and support neurons providing energy. In the AD brain, astrocytes undergo significant morphological and functional changes that contribute to AD onset and development. However, the extent of this contribution and the role played by oxysterols are still unclear. Here we review the current understanding of the physiological role exerted by astrocytes in the brain and their contribution to AD pathogenesis. In particular, we focus on the impact of cholesterol dysmetabolism on astrocyte functions suggesting new potential approaches to develop therapeutic strategies aimed at counteracting AD development.
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Gamba P, Giannelli S, Staurenghi E, Testa G, Sottero B, Biasi F, Poli G, Leonarduzzi G. The Controversial Role of 24-S-Hydroxycholesterol in Alzheimer's Disease. Antioxidants (Basel) 2021; 10:antiox10050740. [PMID: 34067119 PMCID: PMC8151638 DOI: 10.3390/antiox10050740] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/29/2021] [Accepted: 05/03/2021] [Indexed: 01/19/2023] Open
Abstract
The development of Alzheimer’s disease (AD) is influenced by several events, among which the dysregulation of cholesterol metabolism in the brain plays a major role. Maintenance of brain cholesterol homeostasis is essential for neuronal functioning and brain development. To maintain the steady-state level, excess brain cholesterol is converted into the more hydrophilic metabolite 24-S-hydroxycholesterol (24-OHC), also called cerebrosterol, by the neuron-specific enzyme CYP46A1. A growing bulk of evidence suggests that cholesterol oxidation products, named oxysterols, are the link connecting altered cholesterol metabolism to AD. It has been shown that the levels of some oxysterols, including 27-hydroxycholesterol, 7β-hydroxycholesterol and 7-ketocholesterol, significantly increase in AD brains contributing to disease progression. In contrast, 24-OHC levels decrease, likely due to neuronal loss. Among the different brain oxysterols, 24-OHC is certainly the one whose role is most controversial. It is the dominant oxysterol in the brain and evidence shows that it represents a signaling molecule of great importance for brain function. However, numerous studies highlighted the potential role of 24-OHC in favoring AD development, since it promotes neuroinflammation, amyloid β (Aβ) peptide production, oxidative stress and cell death. In parallel, 24-OHC has been shown to exert several beneficial effects against AD progression, such as preventing tau hyperphosphorylation and Aβ production. In this review we focus on the current knowledge of the controversial role of 24-OHC in AD pathogenesis, reporting a detailed overview of the findings about its levels in different AD biological samples and its noxious or neuroprotective effects in the brain. Given the relevant role of 24-OHC in AD pathophysiology, its targeting could be useful for disease prevention or slowing down its progression.
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Testa G, Staurenghi E, Giannelli S, Sottero B, Gargiulo S, Poli G, Gamba P, Leonarduzzi G. Up-regulation of PCSK6 by lipid oxidation products: A possible role in atherosclerosis. Biochimie 2021; 181:191-203. [PMID: 33359561 DOI: 10.1016/j.biochi.2020.12.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 12/26/2022]
Abstract
Atherosclerosis is a degenerative disease characterized by lesions that develop in the wall of large- and medium-sized arteries due to the accumulation of low-density lipoproteins (LDLs) in the intima. A growing bulk of evidence suggests that cholesterol oxidation products, known as oxysterols, and the aldehyde 4-hydroxy-2-nonenal (HNE), the major pro-atherogenic components of oxidized LDLs, significantly contribute to atherosclerotic plaque progression and destabilization, with eventual plaque rupture. The involvement of certain members of the protein convertase subtilisin/kexin proteases (PCSKs) in atherosclerosis has been recently hypothesized. Among them, PCSK6 has been associated with plaque instability, mainly thanks to its ability to stimulate the activity of matrix metalloproteinases (MMPs) involved in extracellular matrix remodeling and to enhance inflammation. In U937 promonocytic cells and in human umbilical vein endothelial cells, an oxysterol mixture and HNE were able to up-regulate the level and activity of PCSK6, resulting in MMP-9 activation as demonstrated by PCSK6 silencing. Inflammation, enhanced by these lipid oxidation products, plays a key role in the up-regulation of PCSK6 activity as demonstrated by cell pretreatment with NS-398, with epigallocatechin gallate or with acetylsalicylic acid, all with anti-inflammatory effects. For the first time, we demonstrated that both oxysterols and HNE, which substantially accumulate in the atherosclerotic plaque, up-regulate the activity of PCSK6. Of note, we also suggest a potential association between PCSK6 activity and MMP-9 activation, pointing out that PCSK6 could contribute to atherosclerotic plaque development.
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Affiliation(s)
- Gabriella Testa
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, 10043, Orbassano, Turin, Italy
| | - Erica Staurenghi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, 10043, Orbassano, Turin, Italy
| | - Serena Giannelli
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, 10043, Orbassano, Turin, Italy
| | - Barbara Sottero
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, 10043, Orbassano, Turin, Italy
| | - Simona Gargiulo
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, 10043, Orbassano, Turin, Italy
| | - Giuseppe Poli
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, 10043, Orbassano, Turin, Italy
| | - Paola Gamba
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, 10043, Orbassano, Turin, Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, 10043, Orbassano, Turin, Italy.
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Staurenghi E, Cerrato V, Gamba P, Testa G, Giannelli S, Leoni V, Caccia C, Buffo A, Noble W, Perez-Nievas BG, Leonarduzzi G. Oxysterols present in Alzheimer's disease brain induce synaptotoxicity by activating astrocytes: A major role for lipocalin-2. Redox Biol 2020; 39:101837. [PMID: 33360775 PMCID: PMC7772793 DOI: 10.1016/j.redox.2020.101837] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/14/2020] [Accepted: 12/14/2020] [Indexed: 01/19/2023] Open
Abstract
Among Alzheimer's disease (AD) brain hallmarks, the presence of reactive astrocytes was demonstrated to correlate with neuronal loss and cognitive deficits. Evidence indeed supports the role of reactive astrocytes as mediators of changes in neurons, including synapses. However, the complexity and the outcomes of astrocyte reactivity are far from being completely elucidated. Another key role in AD pathogenesis is played by alterations in brain cholesterol metabolism. Oxysterols (cholesterol oxidation products) are crucial for brain cholesterol homeostasis, and we previously demonstrated that changes in the brain levels of various oxysterols correlate with AD progression. Moreover, oxysterols have been shown to contribute to various pathological mechanisms involved in AD pathogenesis. In order to deepen the role of oxysterols in AD, we investigated whether they could contribute to astrocyte reactivity, and consequently impact on neuronal health. Results showed that oxysterols present in mild or severe AD brains induce a clear morphological change in mouse primary astrocytes, accompanied by the upregulation of some reactive astrocyte markers, including lipocalin-2 (Lcn2). Moreover, astrocyte conditioned media analysis revealed a significant increase in the release of Lcn2, cytokines, and chemokines in response to oxysterols. A significant reduction of postsynaptic density protein 95 (PSD95) and a concurrent increase in cleaved caspase-3 protein levels have been demonstrated in neurons co-cultured with oxysterol-treated astrocytes, pointing out that mediators released by astrocytes have an impact on neurons. Among these mediators, Lcn2 has been demonstrated to play a major role on synapses, affecting neurite morphology and decreasing dendritic spine density. These data demonstrated that oxysterols present in the AD brain promote astrocyte reactivity, determining the release of several mediators that affect neuronal health and synapses. Lcn2 has been shown to exert a key role in mediating the synaptotoxic effect of oxysterol-treated astrocytes.
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Affiliation(s)
- Erica Staurenghi
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Turin, Italy.
| | - Valentina Cerrato
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi, Orbassano, Turin, Italy
| | - Paola Gamba
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Turin, Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Turin, Italy
| | - Serena Giannelli
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Turin, Italy
| | - Valerio Leoni
- Department of Medicine and Surgery, University of Milan-Bicocca, Desio, Monza-Brianza (MB), Italy
| | - Claudio Caccia
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Annalisa Buffo
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi, Orbassano, Turin, Italy
| | - Wendy Noble
- Institute of Psychiatry, Psychology and Neuroscience, Department of Basic and Clinical Neuroscience, King's College London, London, UK
| | - Beatriz Gomez Perez-Nievas
- Institute of Psychiatry, Psychology and Neuroscience, Department of Basic and Clinical Neuroscience, King's College London, London, UK
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Turin, Italy
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Sottero B, Rossin D, Staurenghi E, Gamba P, Poli G, Testa G. Omics analysis of oxysterols to better understand their pathophysiological role. Free Radic Biol Med 2019; 144:55-71. [PMID: 31141713 DOI: 10.1016/j.freeradbiomed.2019.05.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/30/2019] [Accepted: 05/24/2019] [Indexed: 12/12/2022]
Abstract
High amounts of cholesterol have been definitely associated with the pathogenesis of several diseases, including metabolic and neurodegenerative disorders, cardiovascular diseases, and cancer. In all these pathologies the exacerbation of pro-oxidant and inflammatory responses is a consistent feature. In this scenario, species derived from enzymatic and non-enzymatic cholesterol oxidation, namely oxysterols, are strongly suspected to play a primary role. The consideration of these bioactive lipids is therefore helpful in investigating pathological mechanisms and may also acquire clinical value for the diagnosis and treatment of diseases. For this purpose and considering that a great number of oxysterols may be present together in the body, the employment of lipidomics technology certainly represents a powerful strategy for the simultaneous detection and characterization of these compounds in biological specimens. In this review, we will discuss the applicability of the lipidomics approach in the study of the association between oxysterols and diseases.
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Affiliation(s)
- Barbara Sottero
- Department of Clinical and Biological Sciences, San Luigi Hospital, University of Torino, Italy.
| | - Daniela Rossin
- Department of Clinical and Biological Sciences, San Luigi Hospital, University of Torino, Italy
| | - Erica Staurenghi
- Department of Clinical and Biological Sciences, San Luigi Hospital, University of Torino, Italy
| | - Paola Gamba
- Department of Clinical and Biological Sciences, San Luigi Hospital, University of Torino, Italy
| | - Giuseppe Poli
- Department of Clinical and Biological Sciences, San Luigi Hospital, University of Torino, Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, San Luigi Hospital, University of Torino, Italy
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Gamba P, Staurenghi E, Testa G, Giannelli S, Sottero B, Leonarduzzi G. A Crosstalk Between Brain Cholesterol Oxidation and Glucose Metabolism in Alzheimer's Disease. Front Neurosci 2019; 13:556. [PMID: 31213973 PMCID: PMC6554318 DOI: 10.3389/fnins.2019.00556] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 05/14/2019] [Indexed: 12/14/2022] Open
Abstract
In Alzheimer’s disease (AD), both cholesterol and glucose dysmetabolism precede the onset of memory deficit and contribute to the disease’s progression. It is indeed now believed that oxidized cholesterol in the form of oxysterols and altered glucose uptake are the main triggers in AD affecting production and clearance of Aβ, and tau phosphorylation. However, only a few studies highlight the relationship between them, suggesting the importance of further extensive studies on this topic. Recently, a molecular link was demonstrated between cholesterol oxidative metabolism and glucose uptake in the brain. In particular, 27-hydroxycholesterol, a key linker between hypercholesterolemia and the increased AD risk, is considered a biomarker for reduced glucose metabolism. In fact, its excess increases the activity of the renin-angiotensin system in the brain, thus reducing insulin-mediated glucose uptake, which has a major impact on brain functioning. Despite this important evidence regarding the role of 27-hydroxycholesterol in regulating glucose uptake by neurons, the involvement of other cholesterol oxidation products that have been clearly demonstrated to be key players in AD cannot be ruled out. This review highlights the current understanding of the potential role of cholesterol and glucose dysmetabolism in AD progression, and the bidirectional crosstalk between these two phenomena.
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Affiliation(s)
- Paola Gamba
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Turin, Italy
| | - Erica Staurenghi
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Turin, Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Turin, Italy
| | - Serena Giannelli
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Turin, Italy
| | - Barbara Sottero
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Turin, Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Turin, Italy
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Gargiulo S, Rossin D, Testa G, Gamba P, Staurenghi E, Biasi F, Poli G, Leonarduzzi G. Up-regulation of COX-2 and mPGES-1 by 27-hydroxycholesterol and 4-hydroxynonenal: A crucial role in atherosclerotic plaque instability. Free Radic Biol Med 2018; 129:354-363. [PMID: 30312760 DOI: 10.1016/j.freeradbiomed.2018.09.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/26/2018] [Accepted: 09/29/2018] [Indexed: 12/12/2022]
Abstract
Atherosclerosis is currently understood to be mainly the consequence of a complicated inflammatory process at the different stages of plaque development. Among the several inflammatory molecules involved, up-regulation of the functional cyclooxygenase 2/membrane-bound prostaglandin E synthase 1 (COX-2/mPGES-1) axis plays a key role in plaque development. Excessive production of oxidized lipids, following low-density lipoprotein (LDL) oxidation, is a characteristic feature of atherosclerosis. Among the oxidized lipids of LDLs, the oxysterol 27-hydroxycholesterol (27-OH) and the aldehyde 4-hydroxynonenal (HNE) substantially accumulate in the atherosclerotic plaque, contributing to its progression and instability through a variety of processes. This study shows that 27-OH and HNE promote up-regulation of both the inducible enzymes COX-2 and mPGES-1, leading to increased production of prostaglandin (PG) E2 and inducible nitric oxide synthase, and the subsequent release of nitric oxide in human promonocytic U937 cells. The study also examined the potential involvement of the functionally coupled COX-2/mPGES-1 in enhancing the production of certain pro-inflammatory cytokines and of matrix metalloproteinase 9 by U937 cells. This enhancement is presumably due to the induction of PGE2 synthesis, as a result of the up-regulation of the COX-2/mPGES-1, stimulated by the two oxidized lipids, 27-OH and HNE. Induction of PGE2 synthesis might thus be a mechanism of plaque instability and eventual rupture, contributing to matrix metalloproteinase production by activated macrophages.
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Affiliation(s)
- Simona Gargiulo
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Daniela Rossin
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Paola Gamba
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Erica Staurenghi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Fiorella Biasi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Giuseppe Poli
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Orbassano, Torino, Italy.
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Gargiulo S, Testa G, Gamba P, Staurenghi E, Poli G, Leonarduzzi G. Oxysterols and 4-hydroxy-2-nonenal contribute to atherosclerotic plaque destabilization. Free Radic Biol Med 2017; 111:140-150. [PMID: 28057601 DOI: 10.1016/j.freeradbiomed.2016.12.037] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 12/22/2016] [Accepted: 12/24/2016] [Indexed: 12/31/2022]
Abstract
A growing bulk of evidence suggests that cholesterol oxidation products, known as oxysterols, and 4-hydroxy-2-nonenal (HNE), the major proatherogenic components of oxidized low density lipoproteins (oxLDLs), significantly contribute to atherosclerotic plaque progression and destabilization, with eventual plaque rupture. These oxidized lipids are involved in various key steps of this complex process, mainly thanks to their ability to induce inflammation, oxidative stress, and apoptosis. This review summarizes the current knowledge of the effects induced by these compounds on vascular cells, after their accumulation in the arterial wall and in the atherosclerotic plaque.
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Affiliation(s)
- Simona Gargiulo
- Department of Clinical and Biological Sciences, University of Torino, San Luigi Hospital, 10043 Orbassano, Torino, Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, University of Torino, San Luigi Hospital, 10043 Orbassano, Torino, Italy
| | - Paola Gamba
- Department of Clinical and Biological Sciences, University of Torino, San Luigi Hospital, 10043 Orbassano, Torino, Italy
| | - Erica Staurenghi
- Department of Clinical and Biological Sciences, University of Torino, San Luigi Hospital, 10043 Orbassano, Torino, Italy
| | - Giuseppe Poli
- Department of Clinical and Biological Sciences, University of Torino, San Luigi Hospital, 10043 Orbassano, Torino, Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, University of Torino, San Luigi Hospital, 10043 Orbassano, Torino, Italy.
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11
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Vurusaner B, Gamba P, Gargiulo S, Testa G, Staurenghi E, Leonarduzzi G, Poli G, Basaga H. Nrf2 antioxidant defense is involved in survival signaling elicited by 27-hydroxycholesterol in human promonocytic cells. Free Radic Biol Med 2016; 91:93-104. [PMID: 26689473 DOI: 10.1016/j.freeradbiomed.2015.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/04/2015] [Accepted: 12/07/2015] [Indexed: 01/08/2023]
Abstract
Cholesterol oxidation products such as oxysterols are considered critical factors in the atherosclerotic plaque formation since they induce oxidative stress, inflammation and apoptotic cell death. 27-hydroxycholesterol (27-OH) is one of the most represented oxysterols in atherosclerotic lesions. We recently showed that relatively low concentrations of 27-OH generated a strong survival signaling through an early and transient increase of cellular ROS level, that enhanced MEK-ERK/PI3K-Akt phosphorylation, in turn responsible of a sustained quenching of ROS production. It remains to identify the link between ERK/Akt up-regulation and the consequent quenching effect on ROS intracellular level that efficiently and markedly delay the pro-apoptotic effect of the oxysterol. Here we report on the potent activation of Nrf2 redox-sensitive transcription factor by low micromolar amount of 27-OH added to U937 promonocytic cells. The 27-OH-exerted induction of Nrf2 and subsequently of the target genes, HO-1 and NQO-1, was proved to be: (i) dependent upon the activation of ERK and Akt pathways, (ii) directly responsible for the quenching of intracellular oxidative stress and by this way (iii) ultimately responsible for the observed oxysterol-induced pro-survival response.
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Affiliation(s)
- Beyza Vurusaner
- Biological Sciences and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli-Tuzla, 34956 Istanbul, Turkey.
| | - Paola Gamba
- Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
| | - Simona Gargiulo
- Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
| | - Erica Staurenghi
- Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
| | - Giuseppe Poli
- Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
| | - Huveyda Basaga
- Biological Sciences and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli-Tuzla, 34956 Istanbul, Turkey.
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Gamba P, Testa G, Gargiulo S, Staurenghi E, Poli G, Leonarduzzi G. Oxidized cholesterol as the driving force behind the development of Alzheimer's disease. Front Aging Neurosci 2015; 7:119. [PMID: 26150787 PMCID: PMC4473000 DOI: 10.3389/fnagi.2015.00119] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/03/2015] [Indexed: 12/21/2022] Open
Abstract
Alzheimer’s disease (AD), the most common neurodegenerative disorder associated with dementia, is typified by the pathological accumulation of amyloid Aβ peptides and neurofibrillary tangles (NFT) within the brain. Considerable evidence indicates that many events contribute to AD progression, including oxidative stress, inflammation, and altered cholesterol metabolism. The brain’s high lipid content makes it particularly vulnerable to oxidative species, with the consequent enhancement of lipid peroxidation and cholesterol oxidation, and the subsequent formation of end products, mainly 4-hydroxynonenal and oxysterols, respectively from the two processes. The chronic inflammatory events observed in the AD brain include activation of microglia and astrocytes, together with enhancement of inflammatory molecule and free radical release. Along with glial cells, neurons themselves have been found to contribute to neuroinflammation in the AD brain, by serving as sources of inflammatory mediators. Oxidative stress is intimately associated with neuroinflammation, and a vicious circle has been found to connect oxidative stress and inflammation in AD. Alongside oxidative stress and inflammation, altered cholesterol metabolism and hypercholesterolemia also significantly contribute to neuronal damage and to progression of AD. Increasing evidence is now consolidating the hypothesis that oxidized cholesterol is the driving force behind the development of AD, and that oxysterols are the link connecting the disease to altered cholesterol metabolism in the brain and hypercholesterolemia; this is because of the ability of oxysterols, unlike cholesterol, to cross the blood brain barrier (BBB). The key role of oxysterols in AD pathogenesis has been strongly supported by research pointing to their involvement in modulating neuroinflammation, Aβ accumulation, and cell death. This review highlights the key role played by cholesterol and oxysterols in the brain in AD pathogenesis.
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Affiliation(s)
- Paola Gamba
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Simona Gargiulo
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Erica Staurenghi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Giuseppe Poli
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
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Leonarduzzi G, Gargiulo S, Gamba P, Testa G, Sottero B, Rossin D, Staurenghi E, Poli G. Modulation of cell signaling pathways by oxysterols in age-related human diseases. Free Radic Biol Med 2014; 75 Suppl 1:S5. [PMID: 26461396 DOI: 10.1016/j.freeradbiomed.2014.10.837] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Cholesterol oxidation products, named oxysterols, may derive from the diet or originate endogenously by autoxidative nonenzymatic modification of cholesterol as well as through enxymatic pathways involved in lipid metabolism and maintenance of cholesterol homeostasis. Oxysterols have been shown to exert several in vitro and in vivo biochemical activities of both physiologic and pathologic relevance and they appear to be implicated in the pathogenesis of various age-related chronic diseases, including atherosclerosis and Alzheimer's disease (AD), where hypercholesterolemia represents a primary risk factor, and a redox state impairment and inflammation seem to play a central role. Our recent studies show that, in cells of the macrophage lineage or in human neuronal cells (differentiated or not), respectively in the contest of atherosclerosis or AD, oxysterols can initiate specific signal transduction pathways that are relevant to the development of these diseases. Regarding atherosclerosis, we have observed that oxysterols can contribute to plaque instability and rupture by enhancing inflammatory responses and matrix turnover through an unbalanced up-regulation of MMP-9. Concerning AD, we have demonstrated that oxysterols may promote neuroinflammatory changes and accelerate APP processing toward β-amyloid production by up-regulating APP and BACE1 protein levels. In addition, TLR4, a key player of immune and inflammatory signaling responses, seems to have an important role in the pathogenesis of both atherosclerosis and AD.
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Affiliation(s)
- Gabriella Leonarduzzi
- University of Torino (University of Torino), Clinical and Biological Sciences, Italy
| | - Simona Gargiulo
- University of Torino (University of Torino), Clinical and Biological Sciences, Italy
| | - Paola Gamba
- University of Torino (University of Torino), Clinical and Biological Sciences, Italy
| | - Gabriella Testa
- University of Torino (University of Torino), Clinical and Biological Sciences, Italy
| | - Barbara Sottero
- University of Torino (University of Torino), Clinical and Biological Sciences, Italy
| | - Daniela Rossin
- University of Torino (University of Torino), Clinical and Biological Sciences, Italy
| | - Erica Staurenghi
- University of Torino (University of Torino), Clinical and Biological Sciences, Italy
| | - Giuseppe Poli
- University of Torino (University of Torino), Clinical and Biological Sciences, Italy
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