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Xu S, Smothers JC, Rye D, Endapally S, Chen H, Li S, Liang G, Kinnebrew M, Rohatgi R, Posner BA, Radhakrishnan A. A cholesterol-binding bacterial toxin provides a strategy for identifying a specific Scap inhibitor that blocks lipid synthesis in animal cells. Proc Natl Acad Sci U S A 2024; 121:e2318024121. [PMID: 38330014 PMCID: PMC10873635 DOI: 10.1073/pnas.2318024121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/15/2023] [Indexed: 02/10/2024] Open
Abstract
Lipid synthesis is regulated by the actions of Scap, a polytopic membrane protein that binds cholesterol in membranes of the endoplasmic reticulum (ER). When ER cholesterol levels are low, Scap activates SREBPs, transcription factors that upregulate genes for synthesis of cholesterol, fatty acids, and triglycerides. When ER cholesterol levels rise, the sterol binds to Scap, triggering conformational changes that prevent activation of SREBPs and halting synthesis of lipids. To achieve a molecular understanding of how cholesterol regulates the Scap/SREBP machine and to identify therapeutics for dysregulated lipid metabolism, cholesterol-mimetic compounds that specifically bind and inhibit Scap are needed. To accomplish this goal, we focused on Anthrolysin O (ALO), a pore-forming bacterial toxin that binds cholesterol with a specificity and sensitivity that is uncannily similar to Scap. We reasoned that a small molecule that would bind and inhibit ALO might also inhibit Scap. High-throughput screening of a ~300,000-compound library for ALO-binding unearthed one molecule, termed UT-59, which binds to Scap's cholesterol-binding site. Upon binding, UT-59 triggers the same conformation changes in Scap as those induced by cholesterol and blocks activation of SREBPs and lipogenesis in cultured cells. UT-59 also inhibits SREBP activation in the mouse liver. Unlike five previously reported inhibitors of SREBP activation, UT-59 is the only one that acts specifically by binding to Scap's cholesterol-binding site. Our approach to identify specific Scap inhibitors such as UT-59 holds great promise in developing therapeutic leads for human diseases stemming from elevated SREBP activation, such as fatty liver and certain cancers.
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Affiliation(s)
- Shimeng Xu
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Jared C. Smothers
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Daphne Rye
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Shreya Endapally
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Hong Chen
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Shili Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Guosheng Liang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Maia Kinnebrew
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
- Department of Medicine, Stanford University School of Medicine, Stanford, CA94305
| | - Rajat Rohatgi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
- Department of Medicine, Stanford University School of Medicine, Stanford, CA94305
| | - Bruce A. Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Arun Radhakrishnan
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
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Liu M, Zhang Z, Chen Y, Feng T, Zhou Q, Tian X. Circadian clock and lipid metabolism disorders: a potential therapeutic strategy for cancer. Front Endocrinol (Lausanne) 2023; 14:1292011. [PMID: 38189049 PMCID: PMC10770836 DOI: 10.3389/fendo.2023.1292011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 11/30/2023] [Indexed: 01/09/2024] Open
Abstract
Recent research has emphasized the interaction between the circadian clock and lipid metabolism, particularly in relation to tumors. This review aims to explore how the circadian clock regulates lipid metabolism and its impact on carcinogenesis. Specifically, targeting key enzymes involved in fatty acid synthesis (SREBP, ACLY, ACC, FASN, and SCD) has been identified as a potential strategy for cancer therapy. By disrupting these enzymes, it may be possible to inhibit tumor growth by interfering with lipid metabolism. Transcription factors, like SREBP play a significant role in regulating fatty acid synthesis which is influenced by circadian clock genes such as BMAL1, REV-ERB and DEC. This suggests a strong connection between fatty acid synthesis and the circadian clock. Therefore, successful combination therapy should target fatty acid synthesis in addition to considering the timing and duration of drug use. Ultimately, personalized chronotherapy can enhance drug efficacy in cancer treatment and achieve treatment goals.
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Affiliation(s)
- Mengsi Liu
- School of Integrated Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan, China
- Hunan Key Laboratory of Traditional Chinese Medicine Prescription and Syndromes Translational Medicine, Hunan University of Chinese Medicine, Changsha, China
- Hunan Province University Key Laboratory of Oncology of Traditional Chinese Medicine, Changsha, China
- Key Laboratory of Traditional Chinese Medicine for Mechanism of Tumor Prevention and Treatment, Hunan University of Chinese Medicine, Changsha, China
| | - Zhen Zhang
- Department of Oncology, Affiliated Hospital of Hunan Academy of Traditional Chinese Medicine, Changsha, China
| | - Yating Chen
- School of Integrated Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan, China
- Hunan Key Laboratory of Traditional Chinese Medicine Prescription and Syndromes Translational Medicine, Hunan University of Chinese Medicine, Changsha, China
- Hunan Province University Key Laboratory of Oncology of Traditional Chinese Medicine, Changsha, China
- Key Laboratory of Traditional Chinese Medicine for Mechanism of Tumor Prevention and Treatment, Hunan University of Chinese Medicine, Changsha, China
| | - Ting Feng
- School of Integrated Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan, China
- Hunan Key Laboratory of Traditional Chinese Medicine Prescription and Syndromes Translational Medicine, Hunan University of Chinese Medicine, Changsha, China
- Hunan Province University Key Laboratory of Oncology of Traditional Chinese Medicine, Changsha, China
- Key Laboratory of Traditional Chinese Medicine for Mechanism of Tumor Prevention and Treatment, Hunan University of Chinese Medicine, Changsha, China
| | - Qing Zhou
- Department of Andrology, The First Affiliated Hospital of Hunan University of Chinese Medicine, Changsha, China
| | - Xuefei Tian
- School of Integrated Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan, China
- Hunan Key Laboratory of Traditional Chinese Medicine Prescription and Syndromes Translational Medicine, Hunan University of Chinese Medicine, Changsha, China
- Hunan Province University Key Laboratory of Oncology of Traditional Chinese Medicine, Changsha, China
- Key Laboratory of Traditional Chinese Medicine for Mechanism of Tumor Prevention and Treatment, Hunan University of Chinese Medicine, Changsha, China
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Xu H, Xin Y, Wang J, Liu Z, Cao Y, Li W, Zhou Y, Wang Y, Liu P. The TICE Pathway: Mechanisms and Potential Clinical Applications. Curr Atheroscler Rep 2023; 25:653-662. [PMID: 37736845 DOI: 10.1007/s11883-023-01147-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2023] [Indexed: 09/23/2023]
Abstract
PURPOSE OF REVIEW Transintestinal cholesterol excretion (TICE) is a non-biliary pathway that excretes excess cholesterol from the body through feces. This article focuses on the research progress of the TICE pathway in the last few years, including the discovery process of the TICE pathway, its molecular mechanism, and potential clinical applications. RECENT FINDINGS Cholesterol homeostasis is vital for cardiovascular diseases, stroke, and neurodegenerative diseases. Beyond the cholesterol excretion via hepatobiliary pathway, TICE contributes significantly to reverse cholesterol transport ex vivo and in vivo. Nuclear receptors are ligand-activated transcription factors that regulate cholesterol metabolism. The farnesoid X receptor (FXR) and liver X receptor (LXR) activated, respectively, by oxysterols and bile acids promote intestinal cholesterol secretion through ABCG5/G8. Nutrient regulators and intestinal flora also modulate cholesterol secretion through the TICE pathway. TICE allows direct elimination of plasma cholesterol, which may provide an attractive therapeutic targets. TICE pathway may provide a potential target to stimulate cholesterol elimination and reduce the risk of cardiovascular diseases.
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Affiliation(s)
- Huimin Xu
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Yiyang Xin
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Jiaxin Wang
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Zixin Liu
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Yutong Cao
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Weiguo Li
- People's Hospital of Hebi, Henan University, Henan, China
| | - Yun Zhou
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China.
| | - Yandong Wang
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China.
| | - Peng Liu
- People's Hospital of Hebi, Henan University, Henan, China.
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Uehara K, Santoleri D, Whitlock AEG, Titchenell PM. Insulin Regulation of Hepatic Lipid Homeostasis. Compr Physiol 2023; 13:4785-4809. [PMID: 37358513 PMCID: PMC10760932 DOI: 10.1002/cphy.c220015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
The incidence of obesity, insulin resistance, and type II diabetes (T2DM) continues to rise worldwide. The liver is a central insulin-responsive metabolic organ that governs whole-body metabolic homeostasis. Therefore, defining the mechanisms underlying insulin action in the liver is essential to our understanding of the pathogenesis of insulin resistance. During periods of fasting, the liver catabolizes fatty acids and stored glycogen to meet the metabolic demands of the body. In postprandial conditions, insulin signals to the liver to store excess nutrients into triglycerides, cholesterol, and glycogen. In insulin-resistant states, such as T2DM, hepatic insulin signaling continues to promote lipid synthesis but fails to suppress glucose production, leading to hypertriglyceridemia and hyperglycemia. Insulin resistance is associated with the development of metabolic disorders such as cardiovascular and kidney disease, atherosclerosis, stroke, and cancer. Of note, nonalcoholic fatty liver disease (NAFLD), a spectrum of diseases encompassing fatty liver, inflammation, fibrosis, and cirrhosis, is linked to abnormalities in insulin-mediated lipid metabolism. Therefore, understanding the role of insulin signaling under normal and pathologic states may provide insights into preventative and therapeutic opportunities for the treatment of metabolic diseases. Here, we provide a review of the field of hepatic insulin signaling and lipid regulation, including providing historical context, detailed molecular mechanisms, and address gaps in our understanding of hepatic lipid regulation and the derangements under insulin-resistant conditions. © 2023 American Physiological Society. Compr Physiol 13:4785-4809, 2023.
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Affiliation(s)
- Kahealani Uehara
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Dominic Santoleri
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Anna E. Garcia Whitlock
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Paul M. Titchenell
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Winarto J, Song DG, Pan CH. The Role of Fucoxanthin in Non-Alcoholic Fatty Liver Disease. Int J Mol Sci 2023; 24:ijms24098203. [PMID: 37175909 PMCID: PMC10179653 DOI: 10.3390/ijms24098203] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/27/2023] [Accepted: 05/01/2023] [Indexed: 05/15/2023] Open
Abstract
Chronic liver disease (CLD) has emerged as a leading cause of human deaths. It caused 1.32 million deaths in 2017, which affected men more than women by a two-to-one ratio. There are various causes of CLD, including obesity, excessive alcohol consumption, and viral infection. Among them, non-alcoholic fatty liver disease (NAFLD), one of obesity-induced liver diseases, is the major cause, representing the cause of more than 50% of cases. Fucoxanthin, a carotenoid mainly found in brown seaweed, exhibits various biological activities against NAFLD. Its role in NAFLD appears in several mechanisms, such as inducing thermogenesis in mitochondrial homeostasis, altering lipid metabolism, and promoting anti-inflammatory and anti-oxidant activities. The corresponding altered signaling pathways are the β3-adorenarine receptor (β3Ad), proliferator-activated receptor gamma coactivator (PGC-1), adenosine monophosphate-activated protein kinase (AMPK), peroxisome proliferator-activated receptor (PPAR), sterol regulatory element binding protein (SREBP), nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), protein kinase B (AKT), SMAD2/3, and P13K/Akt pathways. Fucoxanthin also exhibits anti-fibrogenic activity that prevents non-alcoholic steatohepatitis (NASH) development.
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Affiliation(s)
- Jessica Winarto
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea
- Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung 25451, Republic of Korea
| | - Dae-Geun Song
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea
- Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung 25451, Republic of Korea
| | - Cheol-Ho Pan
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea
- Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung 25451, Republic of Korea
- Microalgae Ask US Co., Ltd., Gangneung 25441, Republic of Korea
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6
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Cho SJ, Pronko A, Yang J, Pagan K, Stout-Delgado H. Role of Cholesterol 25-Hydroxylase (Ch25h) in Mediating Innate Immune Responses to Streptococcus pneumoniae Infection. Cells 2023; 12:570. [PMID: 36831236 PMCID: PMC9953875 DOI: 10.3390/cells12040570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/02/2023] [Accepted: 02/09/2023] [Indexed: 02/12/2023] Open
Abstract
Alveolar macrophages (AM) are long-lived tissue-resident innate immune cells of the airways. AM are key effectors of recognition, initiation, and resolution of the host defense against microbes and play an essential role in mediating host responses to Streptococcus pneumoniae infection. Lipid metabolism in AM can significantly impact cellular function and biology. Dysregulated metabolism contributes to an accumulation of lipids, unfolded protein response induction, and inflammatory cytokine production. Our study was designed to investigate the impact of Ch25h on mediating innate immune responses by macrophages during S. pneumoniae infection. Using wild-type and Ch25-/- mice, we examined the role of cholesterol metabolism on inflammatory cytokine production and bacterial clearance. Our results demonstrate that Ch25h plays an important role in the initiation and intensity of cytokine and chemokine production in the lung during S. pneumoniae infection. In the absence of Ch25h, there was enhanced phagocytosis and bacterial clearance. Taken together, our findings demonstrate the important role of Ch25h in modulating host responsiveness to S. pneumoniae infection.
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Heisler DB, Johnson KA, Ma DH, Ohlson MB, Zhang L, Tran M, Corley CD, Abrams ME, McDonald JG, Schoggins JW, Alto NM, Radhakrishnan A. A concerted mechanism involving ACAT and SREBPs by which oxysterols deplete accessible cholesterol to restrict microbial infection. eLife 2023; 12:e83534. [PMID: 36695568 PMCID: PMC9925056 DOI: 10.7554/elife.83534] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 01/25/2023] [Indexed: 01/26/2023] Open
Abstract
Most of the cholesterol in the plasma membranes (PMs) of animal cells is sequestered through interactions with phospholipids and transmembrane domains of proteins. However, as cholesterol concentration rises above the PM's sequestration capacity, a new pool of cholesterol, called accessible cholesterol, emerges. The transport of accessible cholesterol between the PM and the endoplasmic reticulum (ER) is critical to maintain cholesterol homeostasis. This pathway has also been implicated in the suppression of both bacterial and viral pathogens by immunomodulatory oxysterols. Here, we describe a mechanism of depletion of accessible cholesterol from PMs by the oxysterol 25-hydroxycholesterol (25HC). We show that 25HC-mediated activation of acyl coenzyme A: cholesterol acyltransferase (ACAT) in the ER creates an imbalance in the equilibrium distribution of accessible cholesterol between the ER and PM. This imbalance triggers the rapid internalization of accessible cholesterol from the PM, and this depletion is sustained for long periods of time through 25HC-mediated suppression of SREBPs and continued activation of ACAT. In support of a physiological role for this mechanism, 25HC failed to suppress Zika virus and human coronavirus infection in ACAT-deficient cells, and Listeria monocytogenes infection in ACAT-deficient cells and mice. We propose that selective depletion of accessible PM cholesterol triggered by ACAT activation and sustained through SREBP suppression underpins the immunological activities of 25HC and a functionally related class of oxysterols.
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Affiliation(s)
- David B Heisler
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Kristen A Johnson
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Duo H Ma
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Maikke B Ohlson
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Lishu Zhang
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Michelle Tran
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Chase D Corley
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Michael E Abrams
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Jeffrey G McDonald
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - John W Schoggins
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Neal M Alto
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Arun Radhakrishnan
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
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Nakamura A, Aida Y, Okamoto M, Maeda A, Nagao A, Kitatani K, Takekoshi S, Fujisawa A, Yamamoto Y, Kashiba M. Transferrin, insulin, and progesterone modulate intracellular concentrations of coenzyme Q and cholesterol, products of the mevalonate pathway, in undifferentiated PC12 cells. J Clin Biochem Nutr 2023; 72:199-206. [DOI: 10.3164/jcbn.22-115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/04/2023] [Indexed: 03/19/2023] Open
Affiliation(s)
| | - Yukina Aida
- School of Bionics, Tokyo University of Technology
| | | | - Ayaka Maeda
- School of Bionics, Tokyo University of Technology
| | - Ayaka Nagao
- School of Bionics, Tokyo University of Technology
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Li X, Zhang M, Liu M, Liu TH, Hemba-Waduge RUS, Ji JY. Cdk8 attenuates lipogenesis by inhibiting SREBP-dependent transcription in Drosophila. Dis Model Mech 2022; 15:dmm049650. [PMID: 36305265 PMCID: PMC9702540 DOI: 10.1242/dmm.049650] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 10/14/2022] [Indexed: 10/10/2023] Open
Abstract
Fine-tuning of lipogenic gene expression is important for the maintenance of long-term homeostasis of intracellular lipids. The SREBP family of transcription factors are master regulators that control the transcription of lipogenic and cholesterogenic genes, but the mechanisms modulating SREBP-dependent transcription are still not fully understood. We previously reported that CDK8, a subunit of the transcription co-factor Mediator complex, phosphorylates SREBP at a conserved threonine residue. Here, using Drosophila as a model system, we observed that the phosphodeficient SREBP proteins (SREBP-Thr390Ala) were more stable and more potent in stimulating the expression of lipogenic genes and promoting lipogenesis in vivo than wild-type SREBP. In addition, starvation blocked the effects of wild-type SREBP-induced lipogenic gene transcription, whereas phosphodeficient SREBP was resistant to this effect. Furthermore, our biochemical analyses identified six highly conserved amino acid residues in the N-terminus disordered region of SREBP that are required for its interactions with both Cdk8 and the MED15 subunit of the small Mediator complex. These results support that the concerted actions of Cdk8 and MED15 are essential for the tight regulation of SREBP-dependent transcription. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Xiao Li
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, TX 77843, USA
| | - Meng Zhang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Louisiana Cancer Research Center, 1700 Tulane Avenue, New Orleans, LA 70112, USA
| | - Mengmeng Liu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Louisiana Cancer Research Center, 1700 Tulane Avenue, New Orleans, LA 70112, USA
| | - Tzu-Hao Liu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Louisiana Cancer Research Center, 1700 Tulane Avenue, New Orleans, LA 70112, USA
| | - Rajitha-Udakara-Sampath Hemba-Waduge
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Louisiana Cancer Research Center, 1700 Tulane Avenue, New Orleans, LA 70112, USA
| | - Jun-Yuan Ji
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, TX 77843, USA
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Louisiana Cancer Research Center, 1700 Tulane Avenue, New Orleans, LA 70112, USA
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Zhao C, Li L, Li C, Tang C, Cai J, Liu Y, Yang J, Xi Y, Yang M, Jiang N, Han Y, Liu Y, Luo S, Xiao L, Sun L. PACS-2 deficiency in tubular cells aggravates lipid-related kidney injury in diabetic kidney disease. Mol Med 2022; 28:117. [PMID: 36138342 PMCID: PMC9502582 DOI: 10.1186/s10020-022-00545-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022] Open
Abstract
Background Lipid accumulation in tubular cells plays a key role in diabetic kidney disease (DKD). Targeting lipid metabolism disorders has clinical value in delaying the progression of DKD, but the precise mechanism by which molecules mediate lipid-related kidney injury remains unclear. Phosphofurin acidic cluster sorting protein 2 (PACS-2) is a multifunctional sorting protein that plays a role in lipid metabolism. This study determined the role of PACS-2 in lipid-related kidney injury in DKD. Methods Diabetes was induced by a high-fat diet combined with intraperitoneal injections of streptozotocin (HFD/STZ) in proximal tubule-specific knockout of Pacs-2 mice (PT-Pacs-2−/− mice) and the control mice (Pacs-2fl/fl mice). Transcriptomic analysis was performed between Pacs-2fl/fl mice and PT-Pacs-2−/− mice. Results Diabetic PT-Pacs-2−/− mice developed more severe tubule injury and proteinuria compared to diabetic Pacs-2fl/fl mice, which accompanied with increasing lipid synthesis, uptake and decreasing cholesterol efflux as well as lipid accumulation in tubules of the kidney. Furthermore, transcriptome analysis showed that the mRNA level of sterol O-acyltransferase 1 (Soat1) was up-regulated in the kidney of control PT-Pacs-2−/− mice. Transfection of HK2 cells with PACS-2 siRNA under high glucose plus palmitic acid (HGPA) condition aggravated lipid deposition and increased the expression of SOAT1 and sterol regulatory element-binding proteins (SREBPs), while the effect was blocked partially in that of co-transfection of SOAT1 siRNA. Conclusions PACS-2 has a protective role against lipid-related kidney injury in DKD through SOAT1/SREBPs signaling. Supplementary Information The online version contains supplementary material available at 10.1186/s10020-022-00545-x.
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Affiliation(s)
- Chanyue Zhao
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Li Li
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Chenrui Li
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Chengyuan Tang
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Juan Cai
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Yu Liu
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Jinfei Yang
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Yiyun Xi
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Ming Yang
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Na Jiang
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Yachun Han
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Yan Liu
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Shilu Luo
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Li Xiao
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Lin Sun
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Changsha, 410011, Hunan, China.
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11
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Carvalho-Gontijo R, Han C, Zhang L, Zhang V, Hosseini M, Mekeel K, Schnabl B, Loomba R, Karin M, Brenner DA, Kisseleva T. Metabolic Injury of Hepatocytes Promotes Progression of NAFLD and AALD. Semin Liver Dis 2022; 42:233-249. [PMID: 36001995 PMCID: PMC9662188 DOI: 10.1055/s-0042-1755316] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Nonalcoholic liver disease is a component of metabolic syndrome associated with obesity, insulin resistance, and hyperlipidemia. Excessive alcohol consumption may accelerate the progression of steatosis, steatohepatitis, and fibrosis. While simple steatosis is considered a benign condition, nonalcoholic steatohepatitis with inflammation and fibrosis may progress to cirrhosis, liver failure, and hepatocellular cancer. Studies in rodent experimental models and primary cell cultures have demonstrated several common cellular and molecular mechanisms in the pathogenesis and regression of liver fibrosis. Chronic injury and death of hepatocytes cause the recruitment of myeloid cells, secretion of inflammatory and fibrogenic cytokines, and activation of myofibroblasts, resulting in liver fibrosis. In this review, we discuss the role of metabolically injured hepatocytes in the pathogenesis of nonalcoholic steatohepatitis and alcohol-associated liver disease. Specifically, the role of chemokine production and de novo lipogenesis in the development of steatotic hepatocytes and the pathways of steatosis regulation are discussed.
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Affiliation(s)
- Raquel Carvalho-Gontijo
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla,Department of Surgery, University of California, San Diego School of Medicine, La Jolla
| | - Cuijuan Han
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla,Department of Surgery, University of California, San Diego School of Medicine, La Jolla
| | - Lei Zhang
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla,Department of Surgery, University of California, San Diego School of Medicine, La Jolla
| | - Vivian Zhang
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla,Department of Surgery, University of California, San Diego School of Medicine, La Jolla
| | - Mojgan Hosseini
- Department of Pathology, University of California, San Diego School of Medicine, La Jolla
| | - Kristin Mekeel
- Department of Surgery, University of California, San Diego School of Medicine, La Jolla
| | - Bernd Schnabl
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla
| | - Rohit Loomba
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla
| | - Michael Karin
- Department of Pharmacology, University of California, San Diego School of Medicine, La Jolla
| | - David A. Brenner
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla
| | - Tatiana Kisseleva
- Department of Surgery, University of California, San Diego School of Medicine, La Jolla,Corresponding author: Tatiana Kisseleva, 9500 Gilman Drive, #0063, La Jolla, California 92093, USA. Phone: 858.822.5339,
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12
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Gu Y, Duan S, Ding M, Zheng Q, Fan G, Li X, Li Y, Liu C, Sun R, Liu R. Saikosaponin D attenuates metabolic associated fatty liver disease by coordinately tuning PPARα and INSIG/SREBP1c pathway. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 103:154219. [PMID: 35691075 DOI: 10.1016/j.phymed.2022.154219] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/21/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Metabolic associated fatty liver disease (MAFLD) is a progressive chronic liver disease, yet there is still a lack of effective pharmacological therapies at present. Saikosaponin D (SSd) has been reported to exhibit hepatoprotective and anti-steatosis activities in our previous research. PURPOSE The current study aims to further investigate the underlying mechanisms of SSd on MAFLD from the perspectives of the crosstalk between fatty acid (FA) biosynthesis and catabolism to provide strong support for further clinical management of MAFLD. METHODS A MAFLD mouse model induced by a high-fat diet and glucose-fructose water (HFSW) was used for in vivo study. HepG2 cells, primary mouse hepatocytes and adipocytes were further employed for in vitro studies. RESULTS SSd improved intracellular lipid accumulation both in the liver and adipose tissues in HFSW-fed mice. Mechanistically, SSd may serve as a potent PPARα agonist, and the activation of PPARα by SSd in both hepatocytes and adipocytes not only promoted FA oxidation but also concurrently induced INSIG1/2 expression, which subsequently inhibited SREBP1c maturation and ultimately FA synthesis. Moreover, the regulative effect of SSd on lipid metabolism was abolished by the PPARα inhibitor, GW6471. CONCLUSION This study demonstrated that SSd improved lipid homeostasis by coordinately regulating PPARα activation-mediated both inhibition of SREBP1c-dependent FA biosynthesis and induction of FA degradation, and thus shed novel light on the discovery of SSd-based therapeutic strategies for MAFLD.
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Affiliation(s)
- Yiqing Gu
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, 11 Bei San Huan Dong Lu, Beijing, 100029, China
| | - Shuni Duan
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, 11 Bei San Huan Dong Lu, Beijing, 100029, China
| | - Mingning Ding
- School of Life Sciences, Beijing University of Chinese Medicine, 11 Bei San Huan Dong Lu, Beijing, 100029, China
| | - Qi Zheng
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, 11 Bei San Huan Dong Lu, Beijing, 100029, China
| | - Guifang Fan
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, 11 Bei San Huan Dong Lu, Beijing, 100029, China
| | - Xiaojiaoyang Li
- School of Life Sciences, Beijing University of Chinese Medicine, 11 Bei San Huan Dong Lu, Beijing, 100029, China
| | - Yijie Li
- School of Life Sciences, Beijing University of Chinese Medicine, 11 Bei San Huan Dong Lu, Beijing, 100029, China
| | - Chuanyang Liu
- School of Life Sciences, Beijing University of Chinese Medicine, 11 Bei San Huan Dong Lu, Beijing, 100029, China
| | - Rong Sun
- The Second Hospital of Shandong University, Shan Dong University, 247 Bei Yuan Da Jie, Jinan, 250033, China
| | - Runping Liu
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, 11 Bei San Huan Dong Lu, Beijing, 100029, China.
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13
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Shan MY, Dai Y, Ren XD, Zheng J, Zhang KB, Chen B, Yan J, Xu ZH. Berberine mitigates nonalcoholic hepatic steatosis by downregulating SIRT1-FoxO1-SREBP2 pathway for cholesterol synthesis. JOURNAL OF INTEGRATIVE MEDICINE-JIM 2021; 19:545-554. [PMID: 34686466 DOI: 10.1016/j.joim.2021.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 05/31/2021] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To investigate effects of berberine (BBR) on cholesterol synthesis in HepG2 cells with free fatty acid (FFA)-induced steatosis and to explore the underlying mechanisms. METHODS A steatosis cell model was induced in HepG2 cell line fed with FFA (0.5 mmol/L, oleic acid:palmitic acid = 2:1), and then treated with three concentrations of BBR; cell viability was assessed with cell counting kit-8 assays. Lipid accumulation in cells was observed through oil red O staining and total cholesterol (TC) content was detected by TC assay. The effects of BBR on cholesterol synthesis mediators were assessed by Western blotting and quantitative polymerase chain reaction. In addition, both silent information regulator 1 (SIRT1) and forkhead box transcription factor O1 (FoxO1) inhibitors were employed for validation. RESULTS FFA-induced steatosis was successfully established in HepG2 cells. Lipid accumulation and TC content in BBR groups were significantly lower (P < 0.05, P < 0.01), associated with significantly higher mRNA and protein levels of SIRT1(P < 0.05, P < 0.01), significantly lower sterol regulatory element-binding protein 2 (SREBP2) and 3-hydroxy 3-methylglutaryl-CoA reductase levels (P < 0.05, P < 0.01), as well as higher Acetyl-FoxO1 protein level (P < 0.05, P < 0.01) compared to the FFA only group. Both SIRT1 inhibitor SIRT1-IN-1 and FoxO1 inhibitor AS1842856 blocked the BBR-mediated therapeutic effects. Immunofluorescence showed that the increased SIRT1 expression increased FoxO1 deacetylation, and promoted its nuclear translocation. CONCLUSION BBR can mitigate FFA-induced steatosis in HepG2 cells by activating SIRT1-FoxO1-SREBP2 signal pathway. BBR may emerge as a potential drug candidate for treating nonalcoholic hepatic steatosis.
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Affiliation(s)
- Meng-Ya Shan
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Ying Dai
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Xiao-Dan Ren
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Jing Zheng
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Ke-Bin Zhang
- National Drug Clinical Trail Institution, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Bin Chen
- Department of Biochemistry and Molecular Biology, Army Medical University, Chongqing 400038, China
| | - Jun Yan
- Department 1, Research Institute of Surgery & Daping Hospital, Army Medical Center of Chinese People's Liberation Army, Army Medical University, Chongqing 400042, China
| | - Zi-Hui Xu
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing 400037, China.
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14
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Huang Y, Wang S, Meng X, Chen N, Li S. Molecular Cloning and Characterization of Sirtuin 1 and Its Potential Regulation of Lipid Metabolism and Antioxidant Response in Largemouth Bass ( Micropterus salmoides). Front Physiol 2021; 12:726877. [PMID: 34646155 PMCID: PMC8504536 DOI: 10.3389/fphys.2021.726877] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/06/2021] [Indexed: 12/24/2022] Open
Abstract
Sirtuin 1 (SIRT1) of largemouth bass (Micropterus salmoides) was cloned and characterized in the present study and the influence of SIRT1 activation induced by resveratrol inclusion on the expression of genes related to lipid metabolism and antioxidation was also investigated. The SIRT1 of largemouth bass, with full-length cDNA sequence of 3395bp encoding 695 amino acids, was mainly expressed in gonad, heart and liver. The analysis of multiple sequence alignment revealed that, in accordance with other species, SIRT1 of largemouth bass contained highly conserved substrate-binding site and NAD+ binding site. The result of subcellular localization displayed that SIRT1 of largemouth bass was mainly localized in the nucleus. The inclusion of 1.0 and 2.5‰ dietary RSV, a natural SIRT1 activator, significantly elevated the SIRT1 protein expression. Meanwhile, the phosphorylation of AKT1 and FoxO1 followed similar pattern with that of SIRT1, indicating the activation of insulin pathway, which may result in the inhibition of lipogenesis and activation of lipolysis, and reduced hepatic triglycerides content. Additionally, the activation of SIRT1 induced by dietary RSV elevated the antioxidant capacity at both transcriptional level and enzymatic level, which was probably mediated by the transcription factor Nrf2. In above, SIRT1 was suggested to be involved in improving antioxidant capacity and alleviating hepatic lipid deposition in largemouth bass.
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Affiliation(s)
- Yuting Huang
- Research Centre of the Ministry of Agriculture and Rural Affairs on Environmental Ecology and Fish Nutrition, Shanghai Ocean University, Shanghai, China
| | - Shilin Wang
- Research Centre of the Ministry of Agriculture and Rural Affairs on Environmental Ecology and Fish Nutrition, Shanghai Ocean University, Shanghai, China
| | - Xiaoxue Meng
- Research Centre of the Ministry of Agriculture and Rural Affairs on Environmental Ecology and Fish Nutrition, Shanghai Ocean University, Shanghai, China
| | - Naisong Chen
- Research Centre of the Ministry of Agriculture and Rural Affairs on Environmental Ecology and Fish Nutrition, Shanghai Ocean University, Shanghai, China.,National Demonstration Center on Experiment Teaching of Fisheries Science, Shanghai Ocean University, Shanghai, China
| | - Songlin Li
- Research Centre of the Ministry of Agriculture and Rural Affairs on Environmental Ecology and Fish Nutrition, Shanghai Ocean University, Shanghai, China.,National Demonstration Center on Experiment Teaching of Fisheries Science, Shanghai Ocean University, Shanghai, China
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15
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Yang J, Zhou S, Gu Z, Cheng L, Cui C, Shen Y, Hong Y. Effect of starch-hydrocolloid complexes with heat-moisture treatment on in vivo digestibility. Food Funct 2021; 12:8017-8025. [PMID: 34269784 DOI: 10.1039/d1fo01586a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The purpose of this study was to investigate the effect of starch-hydrocolloid (gum arabic, xanthan gum, and guar gum) complexes with heat-moisture treatment (HMT) on in vivo digestibility. In vivo digestibility experiments revealed that the body weight, liver weight, and fat index of mice in the intervention group were significantly reduced compared with those in the high-fat group. Glucose tolerance improved, and blood lipid levels, liver and adipose tissue morphology returned to normal. The results of mRNA expression levels showed that the intervention of corn starch-hydrocolloid complexes after HMT down-regulated the expression level of genes related to fat synthesis compared with the high-fat group, which could decrease lipid deposition and stabilize blood lipid levels. Results revealed that starch-xanthan gum complex (1 : 40 ratio) with HMT could markedly reduce the digestibility of starch. Overall, this study provides new ideas for the application of low-glycemic-index and functional foods.
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Affiliation(s)
- Jie Yang
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, Wuxi 214122, Jiangsu Province, China
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16
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Hypocholesterolemic Effect of Potent Peptide and Bioactive Fraction from Pigeon Pea By-Products in Wistar Rats. Int J Pept Res Ther 2021. [DOI: 10.1007/s10989-021-10261-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Domingues MM, Gomes B, Hollmann A, Santos NC. 25-Hydroxycholesterol Effect on Membrane Structure and Mechanical Properties. Int J Mol Sci 2021; 22:ijms22052574. [PMID: 33806504 PMCID: PMC7961727 DOI: 10.3390/ijms22052574] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/08/2021] [Accepted: 02/14/2021] [Indexed: 12/20/2022] Open
Abstract
Cholesterol is responsible for the plasticity of plasma membranes and is involved in physiological and pathophysiological responses. Cholesterol homeostasis is regulated by oxysterols, such as 25-hydroxycholesterol. The presence of 25-hydroxycholesterol at the membrane level has been shown to interfere with several viruses’ entry into their target cells. We used atomic force microscopy to assess the effect of 25-hydroxycholesterol on different properties of supported lipid bilayers with controlled lipid compositions. In particular, we showed that 25-hydroxycholesterol inhibits the lipid-condensing effects of cholesterol, rendering the bilayers less rigid. This study indicates that the inclusion of 25-hydroxycholesterol in plasma membranes or the conversion of part of their cholesterol content into 25-hydroxycholesterol leads to morphological alterations of the sphingomyelin (SM)-enriched domains and promotes lipid packing inhomogeneities. These changes culminate in membrane stiffness variations.
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Affiliation(s)
- Marco M. Domingues
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal;
- Correspondence: (M.M.D.); (N.C.S.)
| | - Bárbara Gomes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal;
| | - Axel Hollmann
- Centro de Investigación en Biofísica Aplicada y Alimentos (CIBAAL), Universidad Nacional de Santiago Del Estero-CONICET, Santiago del Estero 4206, Argentina;
| | - Nuno C. Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal;
- Correspondence: (M.M.D.); (N.C.S.)
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18
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Zarei M, Aguilar-Recarte D, Palomer X, Vázquez-Carrera M. Revealing the role of peroxisome proliferator-activated receptor β/δ in nonalcoholic fatty liver disease. Metabolism 2021; 114:154342. [PMID: 32810487 DOI: 10.1016/j.metabol.2020.154342] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/16/2020] [Accepted: 08/08/2020] [Indexed: 02/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD), a form of chronic liver disease that occurs in individuals with no significant alcohol abuse, has become an increasing concern for global health. NAFLD is defined as the presence of lipid deposits in hepatocytes and it ranges from hepatic steatosis (fatty liver) to steatohepatitis. Emerging data from both preclinical studies and clinical trials suggest that the peroxisome proliferator-activated receptor (PPAR)β/δ plays an important role in the control of carbohydrate and lipid metabolism in liver, and its activation might hinder the progression of NAFLD. Here, we review the latest information on the effects of PPARβ/δ on NAFLD, including its capacity to reduce lipogenesis, to alleviate inflammation and endoplasmic reticulum stress, to ameliorate insulin resistance, and to attenuate liver injury. Because of these effects, activation of hepatic PPARβ/δ through synthetic or natural ligands provides a promising therapeutic option for the management of NAFLD.
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Affiliation(s)
- Mohammad Zarei
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Madrid, Spain; Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - David Aguilar-Recarte
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Madrid, Spain; Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Xavier Palomer
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Madrid, Spain; Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Manuel Vázquez-Carrera
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Madrid, Spain; Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain.
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19
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Cai Z, Ishibashi T, Kozai M, Mita H, Wang S, Takada K, Inaba M. ROR agonist hampers the proliferation and survival of postactivated CD8 + T cells through the downregulation of cholesterol synthesis-related genes. Immunol Cell Biol 2020; 99:288-298. [PMID: 32940916 DOI: 10.1111/imcb.12406] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 08/31/2020] [Accepted: 09/15/2020] [Indexed: 11/30/2022]
Abstract
Cholesterol is a major component of the lipid bilayers of cellular membranes. The synthesis of cholesterol is acutely elevated during T-cell activation to support T-cell growth and proliferation. There is a limited understanding of cholesterol metabolism reprogramming during T-cell activation. Retinoic acid receptor-related orphan receptors (RORs) are ligand-activated nuclear receptors that regulate the transcription of target genes. In this study, we demonstrated that the activation of RORs by a synthetic agonist (SR1078) impairs the proliferation and survival of postactivated CD8+ T cells. The inhibitory effects of SR1078 on CD8+ T-cell proliferation and survival were attributed to cholesterol depletion and downregulated expression of cholesterol metabolism-related genes. The overexpression of RORα or RORγt promoted apoptosis in the postactivated CD8+ T cells in vitro. The expression of RORα (but not that of RORγt) was markedly upregulated in the CD8+ T cells upon stimulation with an antigen in vivo. The functional deficiency of RORα enhanced CD8+ T-cell expansion during the response to bacterial infection. These results suggest that RORs are involved in the regulation of CD8+ T-cell-mediated immune response through the regulation of cholesterol metabolism, which can be modulated by a synthetic ROR agonist. The findings of this study can aid in the development of immunotherapeutic methods that target nuclear receptors.
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Affiliation(s)
- Zimeng Cai
- Laboratory of Molecular Medicine, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Taishin Ishibashi
- Laboratory of Molecular Medicine, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Mina Kozai
- Laboratory of Molecular Medicine, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Hironobu Mita
- Laboratory of Molecular Medicine, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Shangyi Wang
- Laboratory of Molecular Medicine, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Kensuke Takada
- Laboratory of Molecular Medicine, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Mutsumi Inaba
- Laboratory of Molecular Medicine, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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20
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Gesto DS, Pereira CMS, Cerqueira NMFS, Sousa SF. An Atomic-Level Perspective of HMG-CoA-Reductase: The Target Enzyme to Treat Hypercholesterolemia. Molecules 2020; 25:molecules25173891. [PMID: 32859023 PMCID: PMC7503714 DOI: 10.3390/molecules25173891] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/19/2022] Open
Abstract
This review provides an updated atomic-level perspective regarding the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR), linking the more recent data on this enzyme with a structure/function interpretation. This enzyme catalyzes one of the most important steps in cholesterol biosynthesis and is regarded as one of the most important drug targets in the treatment of hypercholesterolemia. Taking this into consideration, we review in the present article several aspects of this enzyme, including its structure and biochemistry, its catalytic mechanism and different reported and proposed approaches for inhibiting this enzyme, including the commercially available statins or the possibility of using dimerization inhibitors.
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Affiliation(s)
- Diana S. Gesto
- UCIBIO, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal;
| | - Carlos M. S. Pereira
- UCIBIO/REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; (C.M.S.P.); (N.M.F.S.C.)
| | - Nuno M. F. S. Cerqueira
- UCIBIO/REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; (C.M.S.P.); (N.M.F.S.C.)
| | - Sérgio F. Sousa
- UCIBIO/REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; (C.M.S.P.); (N.M.F.S.C.)
- Correspondence:
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21
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The cellular function of SCAP in metabolic signaling. Exp Mol Med 2020; 52:724-729. [PMID: 32385422 PMCID: PMC7272406 DOI: 10.1038/s12276-020-0430-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 12/16/2022] Open
Abstract
Sterol regulatory element binding protein (SREBP) cleavage activating protein (SCAP) is a key regulator of SREBP maturation. SCAP induces translocation of SREBP from the endoplasmic reticulum to the Golgi apparatus, allowing it to regulate cellular triglyceride and cholesterol levels. Previous studies have shown that suppression of SREBP activation in SCAP conditional knockout mice reduced the accumulation of intracellular triglycerides, which eventually causes the development of metabolic diseases such as atherosclerosis, diabetes, hepatic steatosis, and insulin resistance. However, despite the significance of SCAP as a regulator of SREBP, its function has not been thoroughly discussed. In this review, we have summarized the function of SCAP and its regulatory proteins. Furthermore, we discuss recent studies regarding SCAP as a possible therapeutic target for hypertriglyceridemia and hyperlipidemia.
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22
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Loregger A, Raaben M, Nieuwenhuis J, Tan JME, Jae LT, van den Hengel LG, Hendrix S, van den Berg M, Scheij S, Song JY, Huijbers IJ, Kroese LJ, Ottenhoff R, van Weeghel M, van de Sluis B, Brummelkamp T, Zelcer N. Haploid genetic screens identify SPRING/C12ORF49 as a determinant of SREBP signaling and cholesterol metabolism. Nat Commun 2020; 11:1128. [PMID: 32111832 PMCID: PMC7048761 DOI: 10.1038/s41467-020-14811-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 02/03/2020] [Indexed: 02/07/2023] Open
Abstract
The sterol-regulatory element binding proteins (SREBP) are central transcriptional regulators of lipid metabolism. Using haploid genetic screens we identify the SREBP Regulating Gene (SPRING/C12ORF49) as a determinant of the SREBP pathway. SPRING is a glycosylated Golgi-resident membrane protein and its ablation in Hap1 cells, Hepa1-6 hepatoma cells, and primary murine hepatocytes reduces SREBP signaling. In mice, Spring deletion is embryonic lethal yet silencing of hepatic Spring expression also attenuates the SREBP response. Mechanistically, attenuated SREBP signaling in SPRINGKO cells results from reduced SREBP cleavage-activating protein (SCAP) and its mislocalization to the Golgi irrespective of the cellular sterol status. Consistent with limited functional SCAP in SPRINGKO cells, reintroducing SCAP restores SREBP-dependent signaling and function. Moreover, in line with the role of SREBP in tumor growth, a wide range of tumor cell lines display dependency on SPRING expression. In conclusion, we identify SPRING as a previously unrecognized modulator of SREBP signaling.
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Affiliation(s)
- Anke Loregger
- Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands
| | - Matthijs Raaben
- Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
| | - Joppe Nieuwenhuis
- Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
| | - Josephine M E Tan
- Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands
| | - Lucas T Jae
- Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands.,Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor Lynen-Str. 25, 81377, Munich, Germany
| | - Lisa G van den Hengel
- Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
| | - Sebastian Hendrix
- Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands
| | - Marlene van den Berg
- Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands
| | - Saskia Scheij
- Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands
| | - Ji-Ying Song
- Division of Experimental Animal Pathology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
| | - Ivo J Huijbers
- Mouse Clinic for Cancer and Aging (MCCA) Transgenic Facility, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
| | - Lona J Kroese
- Mouse Clinic for Cancer and Aging (MCCA) Transgenic Facility, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
| | - Roelof Ottenhoff
- Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands
| | - Michel van Weeghel
- Laboratory of Genetic and Metabolic Diseases and Core Facility Metabolomics, Academic Medical Center of the University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands
| | - Bart van de Sluis
- Department of Pediatrics, University Medical Center Groningen, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands.,iPSC/CRISPR Center Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands
| | - Thijn Brummelkamp
- Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands. .,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, A-1090, Vienna, Austria. .,Cancer Genomics Center, Amsterdam, The Netherlands.
| | - Noam Zelcer
- Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands.
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23
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Sun JJ, Zheng LG, Chen CY, Zhang JY, You CH, Zhang QH, Ma HY, Monroig Ó, Tocher DR, Wang SQ, Li YY. MicroRNAs Involved in the Regulation of LC-PUFA Biosynthesis in Teleosts: miR-33 Enhances LC-PUFA Biosynthesis in Siganus canaliculatus by Targeting insig1 which in Turn Upregulates srebp1. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2019; 21:475-487. [PMID: 31020472 DOI: 10.1007/s10126-019-09895-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
Post-transcriptional regulatory mechanisms play important roles in the regulation of LC-PUFA biosynthesis. Our previous study revealed that miR-33 could increase the expression of fatty acyl desaturases (fads2) in the rabbitfish Siganus canaliculatus, but the specific mechanism is unknown. Here, we confirmed that miR-33 could target the 3'UTR of insulin-induced gene 1 (insig1), resulting in downregulation of its protein level in the rabbitfish hepatocyte line (SCHL). In vitro overexpression of miR-33 inhibited the mRNA level of insig1 and increased the mRNA levels of Δ6Δ5 fads2 and elovl5, as well as srebp1. In SCHL cells, proteolytic activation of sterol-regulatory-element-binding protein-1 (Srebp1) was blocked by Insig1, with overexpression of insig1 decreasing mature Srebp1 level, while inhibition of insig1 led to the opposite effect. Srebp1 could enhance the promoter activity of Δ6Δ5 fads2 and elovl5, whose expression levels decreased with knockdown of srebp1 in SCHL. Overexpression of miR-33 also resulted in a higher conversion of 18:3n-3 to 18:4n-3 and 20:5n-3 to 22:5n-3, linked to desaturation and elongation via Δ6Δ5 Fads2 and Elovl5, respectively. The results suggested that the mechanism by which miR-33 regulates LC-PUFA biosynthesis in rabbitfish is through enhancing the expression of srebp1 by targeting insig1. The findings here provide more insight to the mechanism of miRNAs involvement in the regulation of LC-PUFA biosynthesis in teleosts.
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Affiliation(s)
- Jun Jun Sun
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China
| | - Li Guo Zheng
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China
| | - Cui Ying Chen
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China
| | - Jin Ying Zhang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China
| | - Cui Hong You
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China
| | - Qing Hao Zhang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China
| | - Hong Yu Ma
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China
| | - Óscar Monroig
- Instituto de Acuicultura Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), 12595 Ribera de Cabanes, Castellón, Spain
| | - Douglas R Tocher
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, FK9 4LA, UK
| | - Shu Qi Wang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China.
| | - Yuan You Li
- School of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China.
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24
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Chali F, Milior G, Marty S, Morin-Brureau M, Le Duigou C, Savary E, Blugeon C, Jourdren L, Miles R. Lipid markers and related transcripts during excitotoxic neurodegeneration in kainate-treated mice. Eur J Neurosci 2019; 50:1759-1778. [PMID: 30767299 DOI: 10.1111/ejn.14375] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 12/16/2022]
Abstract
Lipid homeostasis is dysregulated in some neurodegenerative diseases and after brain injuries due to excess glutamate or lack of oxygen. However the kinetics and cell specificity of dysregulation in different groups of lipids during excitotoxic neuronal death are not clear. Here we examined the changes during excitotoxic neuronal death induced by injecting kainic acid (KA) into the CA1 region of mouse hippocampus. We compared neuronal loss and glial cell proliferation with changes in lipid-related transcripts and markers for different lipid groups, over 12 days after KA-treatment. As neurons showed initial signs of damage, transcripts and proteins linked to fatty acid oxidation were up-regulated. Cholesterol biosynthesis induced by transcripts controlled by the transcription factor Srebp2 seems to be responsible for a transient increase in neuronal free cholesterol at 1 to 2 days. In microglia, but not in neurons, Perilipin-2 associated lipid droplets were induced and properties of Nile red emissions suggest lipid contents change over time. After microglial expression of phagocytotic markers at 2 days, some neutral lipid deposits co-localized with lysosome markers of microglia and were detected within putative phagocytotic cups. These data delineate distinct lipid signals in neurons and glial cells during excitotoxic processes from initial neuronal damage to engagement of the lysosome-phagosome system.
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Affiliation(s)
- Farah Chali
- Inserm U1127, CNRS UMR7225, Sorbonne Université, UPMC Université Paris 6 UMR S1127, Institut du Cerveau et de la Moelle Epinière, CHU Pitié-Salpêtrière, Paris, France
| | - Giampaolo Milior
- Inserm U1127, CNRS UMR7225, Sorbonne Université, UPMC Université Paris 6 UMR S1127, Institut du Cerveau et de la Moelle Epinière, CHU Pitié-Salpêtrière, Paris, France
| | - Serge Marty
- Inserm U1127, CNRS UMR7225, Sorbonne Université, UPMC Université Paris 6 UMR S1127, Institut du Cerveau et de la Moelle Epinière, CHU Pitié-Salpêtrière, Paris, France
| | - Mélanie Morin-Brureau
- Inserm U1127, CNRS UMR7225, Sorbonne Université, UPMC Université Paris 6 UMR S1127, Institut du Cerveau et de la Moelle Epinière, CHU Pitié-Salpêtrière, Paris, France
| | - Caroline Le Duigou
- Inserm U1127, CNRS UMR7225, Sorbonne Université, UPMC Université Paris 6 UMR S1127, Institut du Cerveau et de la Moelle Epinière, CHU Pitié-Salpêtrière, Paris, France
| | - Etienne Savary
- Inserm U1127, CNRS UMR7225, Sorbonne Université, UPMC Université Paris 6 UMR S1127, Institut du Cerveau et de la Moelle Epinière, CHU Pitié-Salpêtrière, Paris, France
| | - Corinne Blugeon
- Institut de Biologie de l'École normale supérieure (IBENS), École Normale Supérieure, CNRS, INSERM PSL Université Paris, Paris, France
| | - Laurent Jourdren
- Institut de Biologie de l'École normale supérieure (IBENS), École Normale Supérieure, CNRS, INSERM PSL Université Paris, Paris, France
| | - Richard Miles
- Inserm U1127, CNRS UMR7225, Sorbonne Université, UPMC Université Paris 6 UMR S1127, Institut du Cerveau et de la Moelle Epinière, CHU Pitié-Salpêtrière, Paris, France
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25
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Shu Z, Gao Y, Zhang G, Zhou Y, Cao J, Wan D, Zhu X, Xiong W. A functional interaction between Hippo-YAP signalling and SREBPs mediates hepatic steatosis in diabetic mice. J Cell Mol Med 2019; 23:3616-3628. [PMID: 30821074 PMCID: PMC6484311 DOI: 10.1111/jcmm.14262] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/21/2019] [Accepted: 02/11/2019] [Indexed: 12/14/2022] Open
Abstract
The Hippo pathway is an evolutionarily conserved regulator of organ size and tumorigenesis that negatively regulates cell growth and survival. Whether the Hippo pathway regulates cell metabolism is unknown. Here, we report that in the nucleus of hepatocytes, Yes‐associated protein(YAP)—the terminal effector of the Hippo pathway—directly interacts with sterol regulatory element binding proteins (SREBP‐1c and SREBP‐2) on the promoters of the fatty acid synthase (FAS) and 30‐hydroxylmethyl glutaryl coenzyme A reductase (HMGCR), thereby stimulating their transcription and promoting hepatocyte lipogenesis and cholesterol synthesis. In diet‐induced diabetic mice, either Lats1 overexpression or YAP knockdown protects against hepatic steatosis and hyperlipidaemia through suppression of the interaction between YAP and SREBP‐1c/SREBP‐2. These results suggest that YAP is a nuclear co‐factor of SREBPs and that the Hippo pathway negatively affects hepatocyte lipogenesis by inhibiting the function of YAP‐SREBP complexes.
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Affiliation(s)
- Zhiping Shu
- Department of Nuclear Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan Gao
- Department of Nuclear Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guopeng Zhang
- Department of Nuclear Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu Zhou
- Department of Nuclear Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Cao
- Department of Nuclear Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dongyi Wan
- Department of Nuclear Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaohua Zhu
- Department of Nuclear Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wenqian Xiong
- Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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26
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Tsai JW, Kostyleva R, Chen PL, Rivas-Serna IM, Clandinin MT, Meinertzhagen IA, Clandinin TR. Transcriptional Feedback Links Lipid Synthesis to Synaptic Vesicle Pools in Drosophila Photoreceptors. Neuron 2019; 101:721-737.e4. [PMID: 30737130 DOI: 10.1016/j.neuron.2019.01.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 12/03/2018] [Accepted: 01/09/2019] [Indexed: 02/06/2023]
Abstract
Neurons can maintain stable synaptic connections across adult life. However, the signals that regulate expression of synaptic proteins in the mature brain are incompletely understood. Here, we describe a transcriptional feedback loop between the biosynthesis and repertoire of specific phospholipids and the synaptic vesicle pool in adult Drosophila photoreceptors. Mutations that disrupt biosynthesis of a subset of phospholipids cause degeneration of the axon terminal and loss of synaptic vesicles. Although degeneration of the axon terminal is dependent on neural activity, activation of sterol regulatory element binding protein (SREBP) is both necessary and sufficient to cause synaptic vesicle loss. Our studies demonstrate that SREBP regulates synaptic vesicle levels by interacting with tetraspanins, critical organizers of membranous organelles. SREBP is an evolutionarily conserved regulator of lipid biosynthesis in non-neuronal cells; our studies reveal a surprising role for this feedback loop in maintaining synaptic vesicle pools in the adult brain.
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Affiliation(s)
- Jessica W Tsai
- Department of Neurobiology, Stanford University, Fairchild D200, 299 W. Campus Drive, Stanford, CA 94305, USA
| | - Ripsik Kostyleva
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Pei-Ling Chen
- Department of Neurobiology, Stanford University, Fairchild D200, 299 W. Campus Drive, Stanford, CA 94305, USA
| | - Irma Magaly Rivas-Serna
- Department of Agriculture, Food, and Nutritional Science, Alberta Institute of Human Nutrition, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - M Thomas Clandinin
- Department of Agriculture, Food, and Nutritional Science, Alberta Institute of Human Nutrition, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Ian A Meinertzhagen
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Thomas R Clandinin
- Department of Neurobiology, Stanford University, Fairchild D200, 299 W. Campus Drive, Stanford, CA 94305, USA.
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27
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Li X, Liu M, Ji JY. Understanding Obesity as a Risk Factor for Uterine Tumors Using Drosophila. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1167:129-155. [PMID: 31520353 DOI: 10.1007/978-3-030-23629-8_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multiple large-scale epidemiological studies have identified obesity as an important risk factor for a variety of human cancers, particularly cancers of the uterus, gallbladder, kidney, liver, colon, and ovary, but there is much uncertainty regarding how obesity increases the cancer risks. Given that obesity has been consistently identified as a major risk factor for uterine tumors, the most common malignancies of the female reproductive system, we use uterine tumors as a pathological context to survey the relevant literature and propose a novel hypothesis: chronic downregulation of the cyclin-dependent kinase 8 (CDK8) module, composed of CDK8 (or its paralog CDK19), Cyclin C, MED12 (or MED12L), and MED13 (or MED13L), by elevated insulin or insulin-like growth factor signaling in obese women may increase the chances to dysregulate the activities of transcription factors regulated by the CDK8 module, thereby increasing the risk of uterine tumors. Although we focus on endometrial cancer and uterine leiomyomas (or fibroids), two major forms of uterine tumors, our model may offer additional insights into how obesity increases the risk of other types of cancers and diseases. To illustrate the power of model organisms for studying human diseases, here we place more emphasis on the findings obtained from Drosophila melanogaster.
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Affiliation(s)
- Xiao Li
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, USA
| | - Mengmeng Liu
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, USA
| | - Jun-Yuan Ji
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, USA.
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28
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Stem cell-secreted 14,15- epoxyeicosatrienoic acid rescues cholesterol homeostasis and autophagic flux in Niemann-Pick-type C disease. Exp Mol Med 2018; 50:1-14. [PMID: 30429460 PMCID: PMC6235958 DOI: 10.1038/s12276-018-0176-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/06/2018] [Accepted: 07/18/2018] [Indexed: 12/27/2022] Open
Abstract
We previously demonstrated that the direct transplantation of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) into the dentate gyrus ameliorated the neurological symptoms of Niemann–Pick type C1 (NPC1)-mutant mice. However, the clinical presentation of NPC1-mutant mice was not fully understood with a molecular mechanism. Here, we found 14,15-epoxyeicosatrienoic acid (14,15-EET), a cytochrome P450 (CYP) metabolite, from hUCB-MSCs and the cerebella of NPC1-mutant mice and investigated the functional consequence of this metabolite. Our screening of the CYP2J family indicated a dysregulation in the CYP system in a cerebellar-specific manner. Moreover, in Purkinje cells, CYP2J6 showed an elevated expression level compared to that of astrocytes, granule cells, and microglia. In this regard, we found that one CYP metabolite, 14,15-EET, acts as a key mediator in ameliorating cholesterol accumulation. In confirming this hypothesis, 14,15-EET treatment reduced the accumulation of cholesterol in human NPC1 patient-derived fibroblasts in vitro by suppressing cholesterol synthesis and ameliorating the impaired autophagic flux. We show that the reduced activity within the CYP system in the cerebellum could cause the neurological symptoms of NPC1 patients, as 14,15-EET treatment significantly rescued cholesterol accumulation and impaired autophagy. We also provide evidence that the intranasal administration of hUCB-MSCs is a highly promising alternative to traumatic surgical transplantation for NPC1 patients. An acid secreted by stem cells can reduce the excess cholesterol caused by a genetic metabolic disorder. Niemann–Pick type C disease is a rare, inherited condition that causes defective muscular development and progressive neurological degeneration. A key disease mechanism is the excessive accumulation of cholesterol within cells. Kyung-Sun Kang at Seoul National University, South Korea, and co-workers have demonstrated that a metabolite molecule called 14,15-epoxyeicosatrienoic acid (14,15-EET) derived from stem cells from human umbilical cord blood significantly reduced cholesterol in Neimann-Pick Type C mouse models and human cell samples. The team administered the stem cell therapy non-invasively via the nose, and observed significant improvements in motor function in the mice. Experiments in both animals and cells showed that the treatment resulted in reduced cholesterol levels and the correction of defective signalling within cells.
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29
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Fujii J, Homma T, Kobayashi S, Seo HG. Mutual interaction between oxidative stress and endoplasmic reticulum stress in the pathogenesis of diseases specifically focusing on non-alcoholic fatty liver disease. World J Biol Chem 2018; 9:1-15. [PMID: 30364769 PMCID: PMC6198288 DOI: 10.4331/wjbc.v9.i1.1] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/19/2018] [Accepted: 10/11/2018] [Indexed: 02/05/2023] Open
Abstract
Reactive oxygen species (ROS) are produced during normal physiologic processes with the consumption of oxygen. While ROS play signaling roles, when they are produced in excess beyond normal antioxidative capacity this can cause pathogenic damage to cells. The majority of such oxidation occurs in polyunsaturated fatty acids and sulfhydryl group in proteins, resulting in lipid peroxidation and protein misfolding, respectively. The accumulation of misfolded proteins in the endoplasmic reticulum (ER) is enhanced under conditions of oxidative stress and results in ER stress, which, together, leads to the malfunction of cellular homeostasis. Multiple types of defensive machinery are activated in unfolded protein response under ER stress to resolve this unfavorable situation. ER stress triggers the malfunction of protein secretion and is associated with a variety of pathogenic conditions including defective insulin secretion from pancreatic β-cells and accelerated lipid droplet formation in hepatocytes. Herein we use nonalcoholic fatty liver disease (NAFLD) as an illustration of such pathological liver conditions that result from ER stress in association with oxidative stress. Protecting the ER by eliminating excessive ROS via the administration of antioxidants or by enhancing lipid-metabolizing capacity via the activation of peroxisome proliferator-activated receptors represent promising therapeutics for NAFLD.
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Affiliation(s)
- Junichi Fujii
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585, Japan
| | - Takujiro Homma
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585, Japan
| | - Sho Kobayashi
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585, Japan
| | - Han Geuk Seo
- Sanghuh College of Life Sciences, Konkuk University, Seoul 143-701, South Korea
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30
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van Leeuwen EM, Emri E, Merle BMJ, Colijn JM, Kersten E, Cougnard-Gregoire A, Dammeier S, Meester-Smoor M, Pool FM, de Jong EK, Delcourt C, Rodrigez-Bocanegra E, Biarnés M, Luthert PJ, Ueffing M, Klaver CCW, Nogoceke E, den Hollander AI, Lengyel I. A new perspective on lipid research in age-related macular degeneration. Prog Retin Eye Res 2018; 67:56-86. [PMID: 29729972 DOI: 10.1016/j.preteyeres.2018.04.006] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/25/2018] [Accepted: 04/30/2018] [Indexed: 12/15/2022]
Abstract
There is an urgency to find new treatment strategies that could prevent or delay the onset or progression of AMD. Different classes of lipids and lipoproteins metabolism genes have been associated with AMD in a multiple ways, but despite the ever-increasing knowledge base, we still do not understand fully how circulating lipids or local lipid metabolism contribute to AMD. It is essential to clarify whether dietary lipids, systemic or local lipoprotein metabolismtrafficking of lipids in the retina should be targeted in the disease. In this article, we critically evaluate what has been reported in the literature and identify new directions needed to bring about a significant advance in our understanding of the role for lipids in AMD. This may help to develop potential new treatment strategies through targeting the lipid homeostasis.
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Affiliation(s)
- Elisabeth M van Leeuwen
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Eszter Emri
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Benedicte M J Merle
- Univ. Bordeaux, Inserm, Bordeaux Population Health Research Center, Team LEHA, UMR 1219, F-33000, Bordeaux, France
| | - Johanna M Colijn
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Eveline Kersten
- Department of Ophthalmology, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands
| | - Audrey Cougnard-Gregoire
- Univ. Bordeaux, Inserm, Bordeaux Population Health Research Center, Team LEHA, UMR 1219, F-33000, Bordeaux, France
| | - Sascha Dammeier
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Germany
| | - Magda Meester-Smoor
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Eiko K de Jong
- Department of Ophthalmology, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands
| | - Cécile Delcourt
- Univ. Bordeaux, Inserm, Bordeaux Population Health Research Center, Team LEHA, UMR 1219, F-33000, Bordeaux, France
| | | | | | | | - Marius Ueffing
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Germany
| | - Caroline C W Klaver
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Ophthalmology, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands
| | - Everson Nogoceke
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Anneke I den Hollander
- Department of Ophthalmology, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Imre Lengyel
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom.
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31
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Nobiletin Inhibits Hepatic Lipogenesis via Activation of AMP-Activated Protein Kinase. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:7420265. [PMID: 29552085 PMCID: PMC5820556 DOI: 10.1155/2018/7420265] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/22/2017] [Accepted: 01/11/2018] [Indexed: 01/14/2023]
Abstract
We aimed to investigate the effects of nobiletin on hepatic lipogenesis in high glucose-induced lipid accumulation in HepG2 cells. Nobiletin, a citrus polymethoxyflavonoid with six methoxy groups, is present abundantly in the peels of citrus fruits. HepG2 cells were incubated in Dulbecco's modified Eagle's medium containing high glucose (25 mM) and subsequently treated with nobiletin at different concentrations (5, 25, and 50 μM). Results showed that nobiletin markedly inhibited high glucose-induced hepatic lipid accumulation in HepG2 cells. In addition, it reduced the protein expression of lipogenic factors, including sterol regulatory element-binding protein 1c (SREBP-1c) and fatty acid synthase (FAS). Nobiletin significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase. Pretreatment with compound C, an AMPK inhibitor, abolished the inhibitory effects of nobiletin on SREBP-1c and FAS expression. These results suggested that nobiletin might attenuate high glucose-induced lipid accumulation in HepG2 hepatocytes via modulation of AMPK signaling pathway. Therefore, nobiletin might be useful for the prevention and treatment of nonalcoholic fatty liver diseases.
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32
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Howe V, Sharpe LJ, Prabhu AV, Brown AJ. New insights into cellular cholesterol acquisition: promoter analysis of human HMGCR and SQLE , two key control enzymes in cholesterol synthesis. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:647-657. [DOI: 10.1016/j.bbalip.2017.03.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 03/22/2017] [Indexed: 01/06/2023]
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33
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Rong S, McDonald JG, Engelking LJ. Cholesterol auxotrophy and intolerance to ezetimibe in mice with SREBP-2 deficiency in the intestine. J Lipid Res 2017. [PMID: 28630260 DOI: 10.1194/jlr.m077610] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
SREBP-2 activates transcription of all genes needed for cholesterol biosynthesis. To study SREBP-2 function in the intestine, we generated a mouse model (Vil-BP2-/- ) in which Cre recombinase ablates SREBP-2 in intestinal epithelia. Intestines of Vil-BP2-/- mice had reduced expression of genes required for sterol synthesis, in vivo sterol synthesis rates, and epithelial cholesterol contents. On a cholesterol-free diet, the mice displayed chronic enteropathy with histological abnormalities of both villi and crypts, growth restriction, and reduced survival that was prevented by supplementation of cholesterol in the diet. Likewise, SREBP-2-deficient enteroids required exogenous cholesterol for growth. Blockade of luminal cholesterol uptake into enterocytes with ezetimibe precipitated acutely lethal intestinal damage in Vil-BP2-/- mice, highlighting the critical interplay in the small intestine of sterol absorption via NPC1L1 and sterol synthesis via SREBP-2 in sustaining the intestinal mucosa. These data show that the small intestine requires SREBP-2 to drive cholesterol synthesis that sustains the intestinal epithelia when uptake of cholesterol from the gut lumen is not available, and provide a unique example of cholesterol auxotrophy expressed in an intact, adult mammal.
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Affiliation(s)
- Shunxing Rong
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Jeffrey G McDonald
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046.,Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Luke J Engelking
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046 .,Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
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Wang J, Zeng L, Zhang L, Guo ZZ, Lu SF, Ming SL, Li GL, Wan B, Tian KG, Yang GY, Chu BB. Cholesterol 25-hydroxylase acts as a host restriction factor on pseudorabies virus replication. J Gen Virol 2017. [DOI: 10.1099/jgv.0.000797] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Jiang Wang
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Lei Zeng
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Li Zhang
- Department of Physiology and Neurobiology, and the Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
| | - Zhen-Zhen Guo
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Shao-Fang Lu
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Sheng-Li Ming
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Guo-Li Li
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Bo Wan
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Ke-Gong Tian
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Guo-Yu Yang
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Bei-Bei Chu
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
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Abstract
Cellular cholesterol levels are intricately controlled to maintain homeostasis. Here, we describe ways in which cellular cholesterol status can be manipulated for the study of cholesterol homeostasis, including sterol starvation (by culturing cells in lipoprotein-deficient serum and pretreating/treating with the cholesterol-lowering drug, statin) and sterol enrichment (using cholesterol complexed to cyclodextrin, and low-density lipoprotein). We also describe how to prepare lipoprotein-deficient serum and complex cholesterol to cyclodextrin.
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Affiliation(s)
- Winnie Luu
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Biological Sciences Building D26, Sydney, NSW, 2052, Australia
| | - Ingrid C Gelissen
- Faculty of Pharmacy, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Biological Sciences Building D26, Sydney, NSW, 2052, Australia.
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Bawazeer NA, Choudary H, Zamzami MA, Abdulaal WH, Zeyadi M, ALbukhari A, Middleton B, Moselhy SS. POSSIBLE REGULATION OF LDL-RECEPTOR BY NARINGENIN IN HEPG2 HEPATOMA CELL LINE. AFRICAN JOURNAL OF TRADITIONAL, COMPLEMENTARY, AND ALTERNATIVE MEDICINES 2016; 14:278-287. [PMID: 28480406 PMCID: PMC5411880 DOI: 10.21010/ajtcam.v14i1.30] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Background: High plasma concentration of low-density lipoprotein cholesterol (LDL-c) plays a significant role in the incidence of atherosclerosis and coronary heart diseases (CHD). Materials and Methods: The purpose of this study was to investigate the mechanism by which citrus flavonoids, naringenin regulate the LDL receptor (LDLr) gene in human liver using the human hepatoma cell line, HepG2 as a model. Results: Time-course transient transfection of HepG2 cells with luciferase reporter-gene constructs incorporating the promoters of SREBP-1a,-1c, -2 and LDLr, revealed that in lipoprotein-deficient medium (LPDM), only SREBP-1a promoter activity was increased significantly after 4h exposure to 200μM naringenin respectively. However, after 24h incubation with 200μM naringenin the gene expression activities of all the SREBP-1a, -1c, -2 and LDLr promoter-constructs were increased significantly. The effects of both 200μM naringenin on elevating LDLr mRNA are possibly due to regulation of gene transcription by SREBP-la and SREBP-2. However, the suppression effect of 200μM naringenin on hepatic SREBP-1c mRNA expression is likely associated with the reduction in mRNA expression of both acetyl-CoA carboxylase and fatty acid synthase in human hepatoma HepG2 cells. It was found that, 200μM naringenin was likely to stimulate LDLr gene expression via increase phosphorylation of PI3K and ERK1/2 which enhance the transcription factors SREBP-1a and SREBP-2 mRNA levels and increased their protein maturation in human hepatoma HepG2 cell. Conclusion: Diets supplemented with naringenin could effectively reduce mortality and morbidity from coronary heart diseases and as cardio-protective effects in humans.
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Affiliation(s)
- Nora A Bawazeer
- Department of Home Economics, Taif University, Taif, Saudi Arabia
| | - Hani Choudary
- Department of Biochemistry, Cancer Metabolism and Epigenetic Unit, Faculty of Science, Center of Innovation in Personalized Medicine, Cancer and Mutagenesis Unit, King Fahd Center for Medical Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mazin A Zamzami
- Department of Biochemistry, Cancer Metabolism and Epigenetic Unit, Faculty of Science, Cancer and Mutagenesis Unit, King Fahd Center for Medical Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Wesam H Abdulaal
- Department of Biochemistry, Cancer Metabolism and Epigenetic Unit, Faculty of Science, Cancer and Mutagenesis Unit, King Fahd Center for Medical Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mustafa Zeyadi
- Department of Biochemistry, Cancer Metabolism and Epigenetic Unit, Faculty of Science, Cancer and Mutagenesis Unit, King Fahd Center for Medical Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ashwag ALbukhari
- Department of Biochemistry, Cancer Metabolism and Epigenetic Unit, Faculty of Science, Cancer and Mutagenesis Unit, King Fahd Center for Medical Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Bruce Middleton
- Department of Biochemistry, Medical School, Nottingham University, Nottingham, United Kingdom
| | - Said S Moselhy
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia and Department of Biochemistry, Faculty of Science, Ain shams University, Cairo, Egypt.,Experimental biochemistry unit, & Bioactive natural products research Group (KAU)
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Effects of SIRT1 gene knock-out via activation of SREBP2 protein-mediated PI3K/AKT signaling on osteoarthritis in mice. ACTA ACUST UNITED AC 2016; 36:683-690. [PMID: 27752896 DOI: 10.1007/s11596-016-1645-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/25/2016] [Indexed: 12/21/2022]
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Aylon Y, Oren M. The Hippo pathway, p53 and cholesterol. Cell Cycle 2016; 15:2248-55. [PMID: 27419353 PMCID: PMC5004696 DOI: 10.1080/15384101.2016.1207840] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 06/19/2016] [Accepted: 06/26/2016] [Indexed: 02/06/2023] Open
Abstract
ASBTRACT Increased rates of cholesterol and lipid synthesis have long been recognized as important aspects of the metabolic rewiring that occurs during cancerous transformation. Many genes encoding enzymes involved in cholesterol and fatty acid biogenesis are transcriptional targets of the sterol regulatory element-binding proteins (SREBPs). The SREBPs act as a hub for metabolic and proliferation-related signals; their activity is the focus of a tug-of-war between tumor suppressors, who generally inhibit SREBP function, and oncogenes, who often promote, and rely on, SREBP activity. The Hippo pathway plays a central role in coordinating cell proliferation and organ size, whereas p53 is a crucial tumor suppressor that maintains metabolic homeostasis and orchestrates cellular stress responses. Together, the Hippo and p53 signaling pathways cooperate on multiple levels to fine-tune SREPB activity and regulate cholesterol/lipid levels. Cholesterol biosynthesis inhibitors such as statins are appealing conceptually, but have yet to show an indisputable effect on cancer development. Fortunately, the complex regulation surrounding the Hippo-p53-SREBP network potentially provides a broad interface for additional novel cancer-targeting interventions.
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Affiliation(s)
- Yael Aylon
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
| | - Moshe Oren
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
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40
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Ferri N, Corsini A, Macchi C, Magni P, Ruscica M. Proprotein convertase subtilisin kexin type 9 and high-density lipoprotein metabolism: experimental animal models and clinical evidence. Transl Res 2016; 173:19-29. [PMID: 26548330 DOI: 10.1016/j.trsl.2015.10.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/03/2015] [Accepted: 10/12/2015] [Indexed: 01/22/2023]
Abstract
Proprotein convertase subtilisin kexin type 9 (PCSK9) belongs to the proprotein convertase family. Several studies have demonstrated its involvement in the regulation of low-density lipoprotein (LDL) cholesterol levels by inducing the degradation of the LDL receptor (LDLR). However, experimental, epidemiologic, and pharmacologic data provide important evidence on the role of PCSK9 also on high-density lipoproteins (HDLs). In mice, PCSK9 regulates the HDL cholesterol (HDL-C) levels by the degradation of hepatic LDLR, thus inhibiting the uptake of apolipoprotein (Apo)E-containing HDLs. Several epidemiologic and genetic studies reported positive relationship between PCSK9 and HDL-C levels, likely by reducing the uptake of the ApoE-containing HDL particles. PCSK9 enhances also the degradation of LDLR's closest family members, ApoE receptor 2, very low-density lipoprotein receptor, and LDLR-related protein 1. This feature provides a molecular mechanism by which PCSK9 may affect HDL metabolism. Experimental studies demonstrated that PCSK9 directly interacts with HDL by modulating PCSK9 self-assembly and its binding to the LDLR. Finally, the inhibition of PCSK9 by means of monoclonal antibodies directed to PCSK9 (ie, evolocumab and alirocumab) determines an increase of HDL-C fraction by 7% and 4.2%, respectively. Thus, the understanding of the role of PCSK9 on HDL metabolism needs to be elucidated with a particular focus on the effect of PCSK9 on HDL-mediated reverse cholesterol transport.
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Affiliation(s)
- Nicola Ferri
- Dipartimento di Scienze del Farmaco, Università di Padova, Padua, Italy.
| | - Alberto Corsini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy; Multimedica IRCCS, Milan, Italy
| | - Chiara Macchi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Paolo Magni
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy; Centro per lo Studio delle Malattie Dismetaboliche e delle Iperlipemie-Enrica Grossi Paoletti, Università degli Studi di Milano, Milan, Italy
| | - Massimiliano Ruscica
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy.
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Wen G, Eder K, Ringseis R. Sterol regulatory element-binding proteins are transcriptional regulators of the thyroglobulin gene in thyroid cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:994-1003. [PMID: 27321819 DOI: 10.1016/j.bbagrm.2016.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/24/2016] [Accepted: 06/15/2016] [Indexed: 01/13/2023]
Abstract
The genes encoding sodium/iodide symporter (NIS) and thyroid peroxidase (TPO), both of which are essential for thyroid hormone (TH) synthesis, were shown to be regulated by sterol regulatory element-binding proteins (SREBP)-1c and -2. In the present study we tested the hypothesis that transcription of a further gene essential for TH synthesis, the thyroglobulin (TG) gene, is under the control of SREBP. To test this hypothesis, we studied the influence of inhibition of SREBP maturation and SREBP knockdown on TG expression in FRTL-5 thyrocytes and explored transcriptional regulation of the TG promoter by reporter gene experiments in FRTL-5 and HepG2 cells, gel shift assays and chromatin immunoprecipitation. Inhibition of SREBP maturation by 25-hydroxycholesterol and siRNA-mediated knockdown of either SREBP-1c or SREBP-2 decreased mRNA and protein levels of TG in FRTL-5 thyrocytes. Reporter gene assays with wild-type and mutated TG promoter reporter truncation constructs revealed that the rat TG promoter is transcriptionally activated by nSREBP-1c and nSREBP-2. DNA-binding assays and chromatin immunoprecipitation assays showed that both nSREBP-1c and nSREBP-2 bind to a SREBP binding motif with characteristics of an E-box SRE at position -63 in the rat TG promoter. In connection with recent findings that NIS and TPO are regulated by SREBP in thyrocytes the present findings support the view that SREBP are regulators of essential steps of TH synthesis in the thyroid gland such as iodide uptake, iodide oxidation and iodination of tyrosyl residues of TG. This moreover suggests that SREBP may be molecular targets for pharmacological modulation of TH synthesis.
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Affiliation(s)
- Gaiping Wen
- Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Gießen, 35392 Gießen, Germany
| | - Klaus Eder
- Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Gießen, 35392 Gießen, Germany
| | - Robert Ringseis
- Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Gießen, 35392 Gießen, Germany.
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Najem D, Bamji-Mirza M, Yang Z, Zhang W. Aβ-Induced Insulin Resistance and the Effects of Insulin on the Cholesterol Synthesis Pathway and Aβ Secretion in Neural Cells. Neurosci Bull 2016; 32:227-38. [PMID: 27207326 DOI: 10.1007/s12264-016-0034-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 04/21/2016] [Indexed: 10/21/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) toxicity, tau pathology, insulin resistance, neuroinflammation, and dysregulation of cholesterol homeostasis, all of which play roles in neurodegeneration. Insulin has polytrophic effects on neurons and may be at the center of these pathophysiological changes. In this study, we investigated possible relationships among insulin signaling and cholesterol biosynthesis, along with the effects of Aβ42 on these pathways in vitro. We found that neuroblastoma 2a (N2a) cells transfected with the human gene encoding amyloid-β protein precursor (AβPP) (N2a-AβPP) produced Aβ and exhibited insulin resistance by reduced p-Akt and a suppressed cholesterol-synthesis pathway following insulin treatment, and by increased phosphorylation of insulin receptor subunit-1 at serine 612 (p-IRS-S612) as compared to parental N2a cells. Treatment of human neuroblastoma SH-SY5Y cells with Aβ42 also increased p-IRS-S612, suggesting that Aβ42 is responsible for insulin resistance. The insulin resistance was alleviated when N2a-AβPP cells were treated with higher insulin concentrations. Insulin increased Aβ release from N2a-AβPP cells, by which it may promote Aβ clearance. Insulin increased cholesterol-synthesis gene expression in SH-SY5Y and N2a cells, including 24-dehydrocholesterol reductase (DHCR24) and 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR) through sterol-regulatory element-binding protein-2 (SREBP2). While Aβ42-treated SH-SY5Y cells exhibited increased HMGCR expression and c-Jun phosphorylation as pro-inflammatory responses, they also showed down-regulation of neuro-protective/anti-inflammatory DHCR24. These results suggest that Aβ42 may cause insulin resistance, activate JNK for c-Jun phosphorylation, and lead to dysregulation of cholesterol homeostasis, and that enhancing insulin signaling may relieve the insulin-resistant phenotype and the dysregulated cholesterol-synthesis pathway to promote Aβ release for clearance from neural cells.
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Affiliation(s)
- Dema Najem
- Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H8M5, Canada.,Human Health Therapeutics, National Research Council of Canada, Ottawa, ON, K1A0R6, Canada
| | - Michelle Bamji-Mirza
- Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H8M5, Canada.,Human Health Therapeutics, National Research Council of Canada, Ottawa, ON, K1A0R6, Canada
| | - Ze Yang
- Beijing Hospital, Institute of Geriatrics-Chinese Health Ministry, Beijing, 100730, China
| | - Wandong Zhang
- Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H8M5, Canada. .,Human Health Therapeutics, National Research Council of Canada, Ottawa, ON, K1A0R6, Canada.
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43
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Blassberg R, Macrae JI, Briscoe J, Jacob J. Reduced cholesterol levels impair Smoothened activation in Smith-Lemli-Opitz syndrome. Hum Mol Genet 2015; 25:693-705. [PMID: 26685159 PMCID: PMC4743690 DOI: 10.1093/hmg/ddv507] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 12/08/2015] [Indexed: 12/21/2022] Open
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is a common autosomal-recessive disorder that results from mutations in the gene encoding the cholesterol biosynthetic enzyme 7-dehydrocholesterol reductase (DHCR7). Impaired DHCR7 function is associated with a spectrum of congenital malformations, intellectual impairment, epileptiform activity and autism spectrum disorder. Biochemically, there is a deficit in cholesterol and an accumulation of its metabolic precursor 7-dehydrocholesterol (7DHC) in developing tissues. Morphological abnormalities in SLOS resemble those seen in congenital Sonic Hedgehog (SHH)-deficient conditions, leading to the proposal that the pathogenesis of SLOS is mediated by aberrant SHH signalling. SHH signalling is transduced through the transmembrane protein Smoothened (SMO), which localizes to the primary cilium of a cell on activation and is both positively and negatively regulated by sterol molecules derived from cholesterol biosynthesis. One proposed mechanism of SLOS involves SMO dysregulation by altered sterol levels, but the salient sterol species has not been identified. Here, we clarify the relationship between disrupted cholesterol metabolism and reduced SHH signalling in SLOS by modelling the disorder in vitro. Our results indicate that a deficit in cholesterol, as opposed to an accumulation of 7DHC, impairs SMO activation and its localization to the primary cilium.
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Affiliation(s)
- Robert Blassberg
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK
| | - James I Macrae
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK
| | - James Briscoe
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK
| | - John Jacob
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Level 6, West Wing, Oxford OX3 9DU, UK, Department of Neurology, Milton Keynes Hospital, Standing Way, Milton Keynes, Buckinghamshire MK6 5LD, UK and Department of Neurology, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
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44
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Xie XJ, Hsu FN, Gao X, Xu W, Ni JQ, Xing Y, Huang L, Hsiao HC, Zheng H, Wang C, Zheng Y, Xiaoli AM, Yang F, Bondos SE, Ji JY. CDK8-Cyclin C Mediates Nutritional Regulation of Developmental Transitions through the Ecdysone Receptor in Drosophila. PLoS Biol 2015. [PMID: 26222308 PMCID: PMC4519132 DOI: 10.1371/journal.pbio.1002207] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The steroid hormone ecdysone and its receptor (EcR) play critical roles in orchestrating developmental transitions in arthropods. However, the mechanism by which EcR integrates nutritional and developmental cues to correctly activate transcription remains poorly understood. Here, we show that EcR-dependent transcription, and thus, developmental timing in Drosophila, is regulated by CDK8 and its regulatory partner Cyclin C (CycC), and the level of CDK8 is affected by nutrient availability. We observed that cdk8 and cycC mutants resemble EcR mutants and EcR-target genes are systematically down-regulated in both mutants. Indeed, the ability of the EcR-Ultraspiracle (USP) heterodimer to bind to polytene chromosomes and the promoters of EcR target genes is also diminished. Mass spectrometry analysis of proteins that co-immunoprecipitate with EcR and USP identified multiple Mediator subunits, including CDK8 and CycC. Consistently, CDK8-CycC interacts with EcR-USP in vivo; in particular, CDK8 and Med14 can directly interact with the AF1 domain of EcR. These results suggest that CDK8-CycC may serve as transcriptional cofactors for EcR-dependent transcription. During the larval–pupal transition, the levels of CDK8 protein positively correlate with EcR and USP levels, but inversely correlate with the activity of sterol regulatory element binding protein (SREBP), the master regulator of intracellular lipid homeostasis. Likewise, starvation of early third instar larvae precociously increases the levels of CDK8, EcR and USP, yet down-regulates SREBP activity. Conversely, refeeding the starved larvae strongly reduces CDK8 levels but increases SREBP activity. Importantly, these changes correlate with the timing for the larval–pupal transition. Taken together, these results suggest that CDK8-CycC links nutrient intake to developmental transitions (EcR activity) and fat metabolism (SREBP activity) during the larval–pupal transition. During the larval-pupal transition in Drosophila, CDK8-CycC helps to link nutrient intake to development by activating ecdysone receptor-dependent transcription and to fat metabolism by inhibiting SREBP-activated gene expression. Arthropods are estimated to account for over 80% of animal species on earth. Characterized by their rigid exoskeletons, juvenile arthropods must periodically shed their thick outer cuticles by molting in order to grow. The steroid hormone ecdysone plays an essential role in regulating the timing of developmental transitions, but exactly how ecdysone and its receptor EcR activates transcription correctly after integrating nutritional and developmental cues remains unknown. Our developmental genetic analyses of two Drosophila mutants, cdk8 and cycC, show that they are lethal during the prepupal stage, with aberrant accumulation of fat and a severely delayed larval–pupal transition. As we have reported previously, CDK8-CycC inhibits fat accumulation by directly inactivating SREBP, a master transcription factor that controls the expression of lipogenic genes, which explains the abnormal fat accumulation in the cdk8 and cycC mutants. We find that CDK8 and CycC are required for EcR to bind to its target genes, serving as transcriptional cofactors for EcR-dependent gene expression. The expression of EcR target genes is compromised in cdk8 and cycC mutants and underpins the retarded pupariation phenotype. Starvation of feeding larvae precociously up-regulates CDK8 and EcR, prematurely down-regulates SREBP activity, and leads to early pupariation, whereas re-feeding starved larvae has opposite effects. Taken together, these results suggest that CDK8 and CycC play important roles in coordinating nutrition intake with fat metabolism by directly inhibiting SREBP-dependent gene expression and regulating developmental timing by activating EcR-dependent transcription in Drosophila.
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Affiliation(s)
- Xiao-Jun Xie
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Fu-Ning Hsu
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Xinsheng Gao
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Los Angeles, United States of America
| | - Jian-Quan Ni
- Gene Regulatory Laboratory, School of Medicine, Tsinghua University, Beijing, China
| | - Yue Xing
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Liying Huang
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Los Angeles, United States of America
| | - Hao-Ching Hsiao
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Haiyan Zheng
- Biological Mass Spectrometry Facility, Robert Wood Johnson Medical School and Rutgers, the State University of New Jersey, Frelinghuysen Road, Piscataway, New Jersey, United States of America
| | - Chenguang Wang
- Key Laboratory of Tianjin Radiation and Molecular Nuclear Medicine; Institute of Radiation Medicine, Peking Union Medical College & Chinese Academy of Medical Sciences, Tianjin, China
| | - Yani Zheng
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Alus M. Xiaoli
- Department of Medicine, Division of Endocrinology, Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Fajun Yang
- Department of Medicine, Division of Endocrinology, Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Sarah E. Bondos
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
- Department of Biosciences, Rice University, Houston, Texas, United States of America
| | - Jun-Yuan Ji
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
- * E-mail:
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Tang SQ, Yin S, Liu S, Le KJ, Yang RL, Liu JH, Wang XL, Zheng ZX, Zheng L, Lin Q, Lu Y. N-stearoyltyrosine dipotassium ameliorates high-fat diet-induced obesity in C57BL/6 mice. Eur J Pharm Sci 2015; 74:18-26. [DOI: 10.1016/j.ejps.2015.03.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 03/14/2015] [Accepted: 03/29/2015] [Indexed: 01/13/2023]
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Oxidative stress triggers lipid droplet accumulation in primary cultured hepatocytes by activating fatty acid synthesis. Biochem Biophys Res Commun 2015; 464:229-35. [PMID: 26116535 DOI: 10.1016/j.bbrc.2015.06.121] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 06/17/2015] [Indexed: 12/12/2022]
Abstract
Despite the impaired intestinal lipid absorption and low level of visceral fat, the Sod1-deficient mouse is susceptible to developing liver steatosis. To gain insights into the mechanism responsible for this abnormal lipid metabolism, we analyzed primary cultured hepatocytes obtained from Sod1-deficient and wild-type mice. Lipid droplets began to accumulate in the cultured hepatocytes and was further increased by a Sod1 deficiency. Levels of enzymes involved in lipogenesis were elevated. It thus appears that lipogenesis is activated by oxidative stress, which is more prominent in the case of Sod1 deficiency, and appears to participate in liver steatosis.
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Flaxseed Oil Containing α -Linolenic Acid Ester of Plant Sterol Improved Atherosclerosis in ApoE Deficient Mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:958217. [PMID: 26180602 PMCID: PMC4477243 DOI: 10.1155/2015/958217] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/05/2015] [Indexed: 01/04/2023]
Abstract
Plant sterols (PS) have potential preventive function in atherosclerosis due to their cholesterol-lowering ability. Dietary α-linolenic acid in flaxseed oil is associated with a reduction in cardiovascular events through its hypolipidemic and anti-inflammation properties. This study was designed to evaluate the effects of flaxseed oil containing α-linolenic acid ester of PS (ALA-PS) on atherosclerosis and investigate the underlying mechanisms. C57BL/6 mice were administered a regular diet and apoE knockout (apoE-KO) mice were given a high fat diet alone or supplemented with 5% flaxseed oil with or without 3.3% ALA-PS for 18 weeks. Results demonstrated that flaxseed oil containing ALA-PS was synergistically interaction in ameliorating atherosclerosis as well as optimizing overall lipid levels, inhibiting inflammation and reducing oxidative stress. These data were associated with the modification effects on expression levels of genes involved in lipid metabolism (PPARα, HMGCR, and SREBPs), inflammation (IL-6, TNF, MCP-1, and VCAM-1), and oxidative stress (NADPH oxidase).
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Using Sterol Substitution to Probe the Role of Membrane Domains in Membrane Functions. Lipids 2015; 50:721-34. [PMID: 25804641 DOI: 10.1007/s11745-015-4007-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 03/03/2015] [Indexed: 02/04/2023]
Abstract
Ordered membrane lipid domains rich in sphingolipids and sterols ("lipid rafts") are thought to be important in many biological processes. However, it is often difficult to distinguish domain-dependent biological functions from ones that have a specific dependence on sterol, e.g. are dependent upon a protein with a function that is dependent upon its binding to sterol. Removing cholesterol and replacing it with various sterols with varying abilities to form membrane domains or otherwise alter membrane properties has the potential to help distinguish these cases. This review describes this strategy, and how it has been applied by various investigators to understand cellular functions.
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Jayanthy G, Subramanian S. RA abrogates hepatic gluconeogenesis and insulin resistance by enhancing IRS-1 and AMPK signalling in experimental type 2 diabetes. RSC Adv 2015. [DOI: 10.1039/c5ra04605j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
RA abrogates hyperglycemia and insulin resistance, the primary features of type 2 diabetes (T2DM).
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Affiliation(s)
- G. Jayanthy
- Department of Biochemistry
- University of Madras
- Guindy Campus
- Chennai
- India
| | - S. Subramanian
- Department of Biochemistry
- University of Madras
- Guindy Campus
- Chennai
- India
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50
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Alioui A, Celhay O, Baron S, Lobaccaro JMA. Lipids and prostate cancer adenocarcinoma. ACTA ACUST UNITED AC 2014. [DOI: 10.2217/clp.14.51] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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