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Damiecki M, Naha R, Schaumkessel Y, Westhoff P, Atanelov N, Stefanski A, Petzsch P, Stühler K, Köhrer K, Weber AP, Anand R, Reichert AS, Kondadi AK. Mitochondrial apolipoprotein MIC26 is a metabolic rheostat regulating central cellular fuel pathways. Life Sci Alliance 2024; 7:e202403038. [PMID: 39393820 DOI: 10.26508/lsa.202403038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2024] [Revised: 09/22/2024] [Accepted: 09/23/2024] [Indexed: 10/13/2024] Open
Abstract
Mitochondria play central roles in metabolism and metabolic disorders such as type 2 diabetes. MIC26, a mitochondrial contact site and cristae organising system complex subunit, was linked to diabetes and modulation of lipid metabolism. Yet, the functional role of MIC26 in regulating metabolism under hyperglycemia is not understood. We used a multi-omics approach combined with functional assays using WT and MIC26 KO cells cultured in normoglycemia or hyperglycemia, mimicking altered nutrient availability. We show that MIC26 has an inhibitory role in glycolysis and cholesterol/lipid metabolism under normoglycemic conditions. Under hyperglycemia, this inhibitory role is reversed demonstrating that MIC26 is critical for metabolic adaptations. This is partially mediated by alterations of mitochondrial metabolite transporters. Furthermore, MIC26 deletion led to a major metabolic rewiring of glutamine use and oxidative phosphorylation. We propose that MIC26 acts as a metabolic "rheostat," that modulates mitochondrial metabolite exchange via regulating mitochondrial cristae, allowing cells to cope with nutrient overload.
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Affiliation(s)
- Melissa Damiecki
- https://ror.org/024z2rq82 Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ritam Naha
- https://ror.org/024z2rq82 Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Yulia Schaumkessel
- https://ror.org/024z2rq82 Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Philipp Westhoff
- https://ror.org/024z2rq82 Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Plant Metabolism and Metabolomics Laboratory, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, Düsseldorf, Germany
| | - Nika Atanelov
- https://ror.org/024z2rq82 Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Anja Stefanski
- https://ror.org/024z2rq82 Molecular Proteomics Laboratory, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Patrick Petzsch
- https://ror.org/024z2rq82 Genomics and Transcriptomics Laboratory, BMFZ, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Kai Stühler
- https://ror.org/024z2rq82 Molecular Proteomics Laboratory, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- https://ror.org/024z2rq82 Institute of Molecular Medicine, Protein Research, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Karl Köhrer
- https://ror.org/024z2rq82 Genomics and Transcriptomics Laboratory, BMFZ, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Andreas Pm Weber
- https://ror.org/024z2rq82 Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Plant Metabolism and Metabolomics Laboratory, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, Düsseldorf, Germany
| | - Ruchika Anand
- https://ror.org/024z2rq82 Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Andreas S Reichert
- https://ror.org/024z2rq82 Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Arun Kumar Kondadi
- https://ror.org/024z2rq82 Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Chen J, Hu J, Guo X, Yang Y, Qin D, Tang X, Huang Z, Wang F, Hu D, Peng D, Yu B. Apolipoprotein O modulates cholesterol metabolism via NRF2/CYB5R3 independent of LDL receptor. Cell Death Dis 2024; 15:389. [PMID: 38830896 PMCID: PMC11148037 DOI: 10.1038/s41419-024-06778-4] [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: 08/03/2023] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/05/2024]
Abstract
Apolipoprotein O (APOO) plays a critical intracellular role in regulating lipid metabolism. Here, we investigated the roles of APOO in metabolism and atherogenesis in mice. Hepatic APOO expression was increased in response to hyperlipidemia but was inhibited after simvastatin treatment. Using a novel APOO global knockout (Apoo-/-) model, it was found that APOO depletion aggravated diet-induced obesity and elevated plasma cholesterol levels. Upon crossing with low-density lipoprotein receptor (LDLR) and apolipoprotein E (APOE) knockout hyperlipidemic mouse models, Apoo-/- Apoe-/- and Apoo-/- Ldlr-/- mice exhibited elevated plasma cholesterol levels, with more severe atherosclerotic lesions than littermate controls. This indicated the effects of APOO on cholesterol metabolism independent of LDLR and APOE. Moreover, APOO deficiency reduced cholesterol excretion through bile and feces while decreasing phospholipid unsaturation by inhibiting NRF2 and CYB5R3. Restoration of CYB5R3 expression in vivo by adeno-associated virus (AAV) injection reversed the reduced degree of phospholipid unsaturation while decreasing blood cholesterol levels. This represents the first in vivo experimental validation of the role of APOO in plasma cholesterol metabolism independent of LDLR and elucidates a previously unrecognized cholesterol metabolism pathway involving NRF2/CYB5R3. APOO may be a metabolic regulator of total-body cholesterol homeostasis and a target for atherosclerosis management. Apolipoprotein O (APOO) regulates plasma cholesterol levels and atherosclerosis through a pathway involving CYB5R3 that regulates biliary and fecal cholesterol excretion, independently of the LDL receptor. In addition, down-regulation of APOO may lead to impaired mitochondrial function, which in turn aggravates diet-induced obesity and fat accumulation.
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Affiliation(s)
- Jin Chen
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China
- Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Jiarui Hu
- Department of Spine Surgery, The Second Xiangya Hospital, Central South University, NO.139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Xin Guo
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China
- Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Yang Yang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China
- Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Donglu Qin
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China
- Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Xiaoyu Tang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Zhijie Huang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China
- Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Fengjiao Wang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China
- Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Die Hu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China
- Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Daoquan Peng
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Bilian Yu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Research Institute of Blood Lipid and Atherosclerosis, Central South University, No.139 Middle Renmin Road, Changsha, 410011, Hunan, China.
- Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China.
- FuRong Laboratory, Changsha, 410078, Hunan, China.
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Kim GH, Jeong HJ, Lee YJ, Park HY, Koo SK, Lim JH. Vitamin D ameliorates age-induced nonalcoholic fatty liver disease by increasing the mitochondrial contact site and cristae organizing system (MICOS) 60 level. Exp Mol Med 2024; 56:142-155. [PMID: 38172593 PMCID: PMC10834941 DOI: 10.1038/s12276-023-01125-7] [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: 01/03/2023] [Revised: 08/27/2023] [Accepted: 10/04/2023] [Indexed: 01/05/2024] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease. Despite intensive research, considerable information on NAFLD development remains elusive. In this study, we examined the effects of vitamin D on age-induced NAFLD, especially in connection with mitochondrial abnormalities. We observed the prevention of NAFLD in 22-month-old C57BL/6 mice fed a vitamin D3-supplemented (20,000 IU/kg) diet compared with mice fed a control (1000 IU/kg) diet. We evaluated whether vitamin D3 supplementation enhanced mitochondrial functions. We found that the level of mitochondrial contact site and cristae organizing system (MICOS) 60 (Mic60) level was reduced in aged mice, and this reduction was specifically restored by vitamin D3. In addition, depletion of Immt, the human gene encoding the Mic60 protein, induced changes in gene expression patterns that led to fat accumulation in both HepG2 and primary hepatocytes, and these alterations were effectively prevented by vitamin D3. In addition, silencing of the vitamin D receptor (VDR) decreased the Mic60 levels, which were recovered by vitamin D treatment. To assess whether VDR directly regulates Mic60 levels, we performed chromatin immunoprecipitation and reporter gene analysis. We discovered that VDR directly binds to the Immt 5' promoter region spanning positions -3157 to -2323 and thereby upregulates Mic60. Our study provides the first demonstration that a reduction in Mic60 levels due to aging may be one of the mechanisms underlying the development of aging-associated NAFLD. In addition, vitamin D3 could positively regulate Mic60 expression, and this may be one of the important mechanisms by which vitamin D could ameliorate age-induced NAFLD.
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Affiliation(s)
- Gyu Hee Kim
- Division of Endocrine and Kidney Disease Research, Department of Chronic Disease Convergence Research, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju, Chungbuk, 28159, Republic of Korea
| | - Hyeon-Ju Jeong
- Division of Endocrine and Kidney Disease Research, Department of Chronic Disease Convergence Research, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju, Chungbuk, 28159, Republic of Korea
| | - Yoo Jeong Lee
- Division of Endocrine and Kidney Disease Research, Department of Chronic Disease Convergence Research, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju, Chungbuk, 28159, Republic of Korea
| | - Hyeon Young Park
- Division of Endocrine and Kidney Disease Research, Department of Chronic Disease Convergence Research, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju, Chungbuk, 28159, Republic of Korea
| | - Soo Kyung Koo
- Division of Endocrine and Kidney Disease Research, Department of Chronic Disease Convergence Research, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju, Chungbuk, 28159, Republic of Korea
| | - Joo Hyun Lim
- Division of Endocrine and Kidney Disease Research, Department of Chronic Disease Convergence Research, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju, Chungbuk, 28159, Republic of Korea.
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El-Darzi N, Mast N, Li Y, Pikuleva IA. APOB100 transgenic mice exemplify how the systemic circulation content may affect the retina without altering retinal cholesterol input. Cell Mol Life Sci 2024; 81:52. [PMID: 38253888 PMCID: PMC10803575 DOI: 10.1007/s00018-023-05056-4] [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: 09/08/2023] [Revised: 10/24/2023] [Accepted: 11/17/2023] [Indexed: 01/24/2024]
Abstract
Apolipoprotein B (APOB) is a constituent of unique lipoprotein particles (LPPs) produced in the retinal pigment epithelium (RPE), which separates the neural retina from Bruch's membrane (BrM) and choroidal circulation. These LPPs accumulate with age in BrM and contribute to the development of age-related macular degeneration, a major blinding disease. The APOB100 transgenic expression in mice, which unlike humans lack the full-length APOB100, leads to lipid deposits in BrM. Herein, we further characterized APOB100 transgenic mice. We imaged mouse retina in vivo and assessed chorioretinal lipid distribution, retinal sterol levels, retinal cholesterol input, and serum content as well as tracked indocyanine green-bound LPPs in mouse plasma and retina after an intraperitoneal injection. Retinal function and differentially expressed proteins were also investigated. APOB100 transgenic mice had increased serum LDL content and an additional higher density HDL subpopulation; their retinal cholesterol levels (initially decreased) became normal with age. The LPP cycling between the RPE and choroidal circulation was increased. Yet, LPP trafficking from the RPE to the neural retina was limited, and total retinal cholesterol input did not change. There were lipid deposits in the RPE and BrM, and retinal function was impaired. Retinal proteomics provided mechanistic insights. Collectively, our data suggested that the serum LDL/HDL ratio may not affect retinal pathways of cholesterol input as serum LPP load is mainly handled by the RPE, which offloads LPP excess to the choroidal circulation rather than neural retina. Different HDL subpopulations should be considered in studies linking serum LPPs and age-related macular degeneration.
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Affiliation(s)
- Nicole El-Darzi
- Department of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Natalia Mast
- Department of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Yong Li
- Department of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Irina A Pikuleva
- Department of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH, 44106, USA.
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Tang X, Huang Z, Wang F, Chen J, Qin D, Peng D, Yu B. Macrophage-specific deletion of MIC26 (APOO) mitigates advanced atherosclerosis by increasing efferocytosis. Atherosclerosis 2023; 386:117374. [PMID: 37995600 DOI: 10.1016/j.atherosclerosis.2023.117374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/01/2023] [Accepted: 11/01/2023] [Indexed: 11/25/2023]
Abstract
BACKGROUND AND AIMS Recent studies have suggested that MIC26 (apolipoprotein O, APOO), a novel mitochondrial inner membrane protein, is involved in inflammation. Thus, the role of macrophage MIC26 in acute inflammation and chronic inflammatory disease atherosclerosis was investigated. METHODS Macrophage-specific MIC26 knockout mice (MIC26LysM) were generated by crossing Apooflox/flox and LysMcre+/- mice. An endotoxemia mouse model was generated to explore the effects of macrophage MIC26 deficiency on acute inflammation, while an atherosclerosis mouse model was constructed by crossing MIC26LysM mice with Apoe-/- mice and challenged with a Western diet. Atherosclerotic plaques, primary macrophage function, and mitochondrial structure and function were analyzed. RESULTS MIC26 knockout did not affect the median survival time and post-injection serum interleukin 1β concentrations in mice with endotoxemia. Mice with MIC26 deficiency in an Apoe-/- background had smaller atherosclerotic lesions and necrotic core than the control group. In vitro studies found that the loss of MIC26 did not affect macrophage polarization, apoptosis, or lipid handling capacity, but increased efferocytosis (the ability to clear apoptotic cells). An in situ efferocytosis assay of plaques also showed that the ratio of macrophage-associated apoptotic cells to free apoptotic cells was higher in the MIC26-deficient group than in the control group, indicating increased efferocytosis. In addition, an in vivo thymus efferocytosis assay indicated that MIC26 deletion promoted efferocytosis. Mechanistically, the loss of MIC26 resulted in an abnormal mitochondrial inner membrane structure, increased mitochondrial fission, and decreased mitochondrial membrane potential. Loss of MIC26 reduced mitochondria optic atrophy type 1 (OPA1) protein, and OPA1 silencing in macrophages promoted efferocytosis. Overexpression of OPA1 abolished the increase in efferocytosis produced by MIC26 deficiency. CONCLUSIONS Macrophage MIC26 deletion alleviated advanced atherosclerosis and necrotic core expansion by promoting efferocytosis. This mechanism may be related to the increased mitochondrial fission caused by reduced mitochondrial OPA1.
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Affiliation(s)
- Xiaoyu Tang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital of Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Department of Rheumatology and Immunology, The Second Xiangya Hospital of Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Clinical Medical Research Center for Systemic Autoimmune Diseases in Hunan Province, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Zhijie Huang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital of Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Fengjiao Wang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital of Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Jin Chen
- Department of Cardiovascular Medicine, The Second Xiangya Hospital of Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Donglu Qin
- Department of Cardiovascular Medicine, The Second Xiangya Hospital of Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Daoquan Peng
- Department of Cardiovascular Medicine, The Second Xiangya Hospital of Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China.
| | - Bilian Yu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital of Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha, 410011, Hunan, China; FuRong Laboratory, Changsha, 410078, Hunan, China.
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Lubeck M, Derkum NH, Naha R, Strohm R, Driessen MD, Belgardt BF, Roden M, Stühler K, Anand R, Reichert AS, Kondadi AK. MIC26 and MIC27 are bona fide subunits of the MICOS complex in mitochondria and do not exist as glycosylated apolipoproteins. PLoS One 2023; 18:e0286756. [PMID: 37279200 DOI: 10.1371/journal.pone.0286756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 05/23/2023] [Indexed: 06/08/2023] Open
Abstract
Impairments of mitochondrial functions are linked to human ageing and pathologies such as cancer, cardiomyopathy, neurodegeneration and diabetes. Specifically, aberrations in ultrastructure of mitochondrial inner membrane (IM) and factors regulating them are linked to diabetes. The development of diabetes is connected to the 'Mitochondrial Contact Site and Cristae Organising System' (MICOS) complex which is a large membrane protein complex defining the IM architecture. MIC26 and MIC27 are homologous apolipoproteins of the MICOS complex. MIC26 has been reported as a 22 kDa mitochondrial and a 55 kDa glycosylated and secreted protein. The molecular and functional relationship between these MIC26 isoforms has not been investigated. In order to understand their molecular roles, we depleted MIC26 using siRNA and further generated MIC26 and MIC27 knockouts (KOs) in four different human cell lines. In these KOs, we used four anti-MIC26 antibodies and consistently detected the loss of mitochondrial MIC26 (22 kDa) and MIC27 (30 kDa) but not the loss of intracellular or secreted 55 kDa protein. Thus, the protein assigned earlier as 55 kDa MIC26 is nonspecific. We further excluded the presence of a glycosylated, high-molecular weight MIC27 protein. Next, we probed GFP- and myc-tagged variants of MIC26 with antibodies against GFP and myc respectively. Again, only the mitochondrial versions of these tagged proteins were detected but not the corresponding high-molecular weight MIC26, suggesting that MIC26 is indeed not post-translationally modified. Mutagenesis of predicted glycosylation sites in MIC26 also did not affect the detection of the 55 kDa protein band. Mass spectrometry of a band excised from an SDS gel around 55 kDa could not confirm the presence of any peptides derived from MIC26. Taken together, we conclude that both MIC26 and MIC27 are exclusively localized in mitochondria and that the observed phenotypes reported previously are exclusively due to their mitochondrial function.
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Affiliation(s)
- Melissa Lubeck
- Medical Faculty and University Hospital Düsseldorf, Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Nick H Derkum
- Medical Faculty and University Hospital Düsseldorf, Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ritam Naha
- Medical Faculty and University Hospital Düsseldorf, Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Rebecca Strohm
- Medical Faculty and University Hospital Düsseldorf, Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Marc D Driessen
- Medical Faculty and University Hospital, Institute of Molecular Medicine, Protein Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Bengt-Frederik Belgardt
- Institute for Vascular and Islet Cell Biology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Partner Düsseldorf, Neuherberg, Germany
| | - Michael Roden
- German Center for Diabetes Research (DZD e.V.), Partner Düsseldorf, Neuherberg, Germany
- Medical Faculty and University Hospital Düsseldorf, Department of Endocrinology and Diabetology, Heinrich Heine University, Düsseldorf, Germany
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes, Heinrich Heine University, Düsseldorf, Germany
| | - Kai Stühler
- Medical Faculty and University Hospital, Institute of Molecular Medicine, Protein Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Molecular Proteomics Laboratory, BMFZ, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ruchika Anand
- Medical Faculty and University Hospital Düsseldorf, Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Andreas S Reichert
- Medical Faculty and University Hospital Düsseldorf, Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Arun Kumar Kondadi
- Medical Faculty and University Hospital Düsseldorf, Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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7
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Guo X, Hu J, He G, Chen J, Yang Y, Qin D, Li C, Huang Z, Hu D, Wei C, Wang F, Yu B. Loss of APOO (MIC26) aggravates obesity-related whitening of brown adipose tissue via PPARα-mediated functional interplay between mitochondria and peroxisomes. Metabolism 2023; 144:155564. [PMID: 37088120 DOI: 10.1016/j.metabol.2023.155564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 04/16/2023] [Accepted: 04/17/2023] [Indexed: 04/25/2023]
Abstract
BACKGROUND Mitochondrial dysfunction and aberrant structure in adipose tissue occur in obesity and obesity-linked brown adipose tissue (BAT) whitening; however, whether this aberrant architecture contributes to or is the result of obesity is unknown. Apolipoprotein O (APOO) is a constitutive protein of the mitochondrial cristae organizing system complex. This study aimed to characterize the physiological consequences of APOO deficiency in vivo. METHODS APOO expression was analyzed in different human and murine adipose depots, and mice lacking APOO in adipocytes (ApooACKO) are developed to examine the metabolic consequences of adipocyte-specific APOO ablation in vitro and in vivo. RESULTS Results showed that APOO expression is reduced in BAT from both diet-induced and leptin-deficient obese mice. APOO-knockout mice showed increased adiposity, BAT dysfunction and whitening, reduced non-shivering thermogenesis, and blunted responses to cold stimuli. APOO deficiency disrupted mitochondrial structure in brown adipocytes and impaired oxidative phosphorylation, thereby inducing a shift from oxidative to glycolytic metabolism, increasing lipogenic enzyme levels and BAT whitening. APOO inactivation inhibited thermogenesis in BAT by reducing mitochondrial long-chain fatty acid oxidation. It also disturbed peroxisomal biogenesis and very long-chain fatty acid oxidation via peroxisome proliferator-activated receptor α. CONCLUSIONS Altogether, APOO deficiency in adipocytes aggravates BAT whitening and diet-induced obesity; thus, APOO could be a therapeutic target for obesity.
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Affiliation(s)
- Xin Guo
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Jiarui Hu
- Department of Spine Surgery, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Guangxu He
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Jin Chen
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Yang Yang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Donglu Qin
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Chenyu Li
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Zhijie Huang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Die Hu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Cheng Wei
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Fengjiao Wang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China
| | - Bilian Yu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Research Institute of Blood Lipid and Atherosclerosis, Central South University, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China; Hunan Key Laboratory of Cardiometabolic Medicine, No. 139 Middle Renmin Road, Changsha 410011, Hunan, China.
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8
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Abstract
Apolipoproteins, the protein component of lipoproteins, play an important role in lipid transport, lipoprotein assembly, and receptor recognition. Apolipoproteins are glycosylated and the glycan moieties play an integral role in apolipoprotein function. Changes in apolipoprotein glycosylation correlate with several diseases manifesting in dyslipidemias. Despite their relevance in apolipoprotein function and diseases, the total glycan repertoire of most apolipoproteins remains undefined. This review summarizes the current knowledge and knowledge gaps regarding human apolipoprotein glycan composition, structure, glycosylation site, and functions. Given the relevance of glycosylation to apolipoprotein function, we expect that future studies of apolipoprotein glycosylation will contribute new understanding of disease processes and uncover relevant biomarkers and therapeutic targets. Considering these future efforts, we also provide a brief overview of current mass spectrometry based technologies that can be applied to define detailed glycan structures, site-specific compositions, and the role of emerging approaches for clinical applications in biomarker discovery and personalized medicine.
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9
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Noborn F, Nilsson J, Larson G. Site-specific glycosylation of proteoglycans: a revisited frontier in proteoglycan research. Matrix Biol 2022; 111:289-306. [PMID: 35840015 DOI: 10.1016/j.matbio.2022.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 06/11/2022] [Accepted: 07/11/2022] [Indexed: 11/29/2022]
Abstract
Proteoglycans (PGs), a class of carbohydrate-modified proteins, are present in essentially all metazoan organisms investigated to date. PGs are composed of glycosaminoglycan (GAG) chains attached to various core proteins and are important for embryogenesis and normal homeostasis. PGs exert many of their functions via their GAG chains and understanding the details of GAG-ligand interactions has been an essential part of PG research. Although PGs are also involved in many diseases, the number of GAG-related drugs used in the clinic is yet very limited, indicating a lack of detailed structure-function understanding. Structural analysis of PGs has traditionally been obtained by first separating the GAG chains from the core proteins, after which the two components are analyzed separately. While this strategy greatly facilitates the analysis, it precludes site-specific information and introduces either a "GAG" or a "core protein" perspective on the data interpretation. Mass-spectrometric (MS) glycoproteomic approaches have recently been introduced, providing site-specific information on PGs. Such methods have revealed a previously unknown structural complexity of the GAG linkage regions and resulted in identification of several novel CSPGs and HSPGs in humans and in model organisms, thereby expanding our view on PG complexity. In light of these findings, we discuss here if the use of such MS-based techniques, in combination with various functional assays, can also be used to expand our functional understanding of PGs. We have also summarized the site-specific information of all human PGs known to date, providing a theoretical framework for future studies on site-specific functional analysis of PGs in human pathophysiology.
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Affiliation(s)
- Fredrik Noborn
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; Department of Laboratory Medicine, Sundsvall County Hospital, Sweden.
| | - Jonas Nilsson
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; Proteomics Core Facility, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Göran Larson
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
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10
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Mostofa MG, Tran M, Gilling S, Lee G, Fraher O, Jin L, Kang H, Park YK, Lee JY, Wang L, Shin DJ. MicroRNA-200c coordinates HNF1 homeobox B and apolipoprotein O functions to modulate lipid homeostasis in alcoholic fatty liver disease. J Biol Chem 2022; 298:101966. [PMID: 35460694 PMCID: PMC9127369 DOI: 10.1016/j.jbc.2022.101966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 02/04/2023] Open
Abstract
Hepatic steatosis is an initial manifestation of alcoholic liver disease. An imbalance of hepatic lipid processes including fatty acid uptake, esterification, oxidation, and triglyceride secretion leads to alcoholic fatty liver (AFL). However, the precise molecular mechanisms underlying the pathogenesis of AFL remain elusive. Here, we show that mice deficient in microRNAs (miRs)-141 and -200c display resistance to the development of AFL. We found that miR-200c directly targets HNF1 homeobox B (Hnf1b), a transcriptional activator for microsomal triglyceride transfer protein (Mttp), as well as apolipoprotein O (ApoO), an integral component of the mitochondrial contact site and cristae organizing system complex. We show that expression of these miRs is significantly induced by chronic ethanol exposure, which is accompanied by reduced HNF1B and APOO levels. Furthermore, miR-141/200c deficiency normalizes ethanol-mediated impairment of triglyceride secretion, which can be attributed to the restored levels of HNF1B and MTTP, as well as phosphatidylcholine abundance. Moreover, we demonstrate that miR-141/200c deficiency restores ethanol-mediated inhibition of APOO expression and mitochondrial dysfunction, improving mitochondrial antioxidant defense capacity and fatty acid oxidation. Taken together, these results suggest that miR-200c contributes to the modulation of lipid homeostasis in AFL disease by cooperatively regulating Hnf1b and ApoO functions.
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Affiliation(s)
- Md Golam Mostofa
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Melanie Tran
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Shaynian Gilling
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Grace Lee
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Ondine Fraher
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Lei Jin
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Hyunju Kang
- Department of Nutritional Sciences, University of Connecticut, Storrs, Connecticut, USA
| | - Young-Ki Park
- Department of Nutritional Sciences, University of Connecticut, Storrs, Connecticut, USA
| | - Ji-Young Lee
- Department of Nutritional Sciences, University of Connecticut, Storrs, Connecticut, USA
| | - Li Wang
- Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, Connecticut, USA
| | - Dong-Ju Shin
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA.
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11
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Liu Y, Xiong Z, Zhou W, Chen Y, Huang Q, Wu Y. Role of apolipoprotein O in autophagy via the p38 mitogen-activated protein kinase signaling pathway in myocardial infarction. Clinics (Sao Paulo) 2022; 77:100046. [PMID: 35588578 PMCID: PMC9120058 DOI: 10.1016/j.clinsp.2022.100046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/10/2022] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE To explore the role and possible mechanisms of action of apolipoprotein O (APOO) in autophagy in Myocardial Infarction (MI) in vivo and in vitro. METHODS Differential gene expression and single Gene Set Enrichment Analysis (GSEA) were used to evaluate MI-related candidate genes. Animal and cell MI models were established. Sh-APOO, si-APOO, and SB203580 were used to inhibit the expression of APOO or p38MAPK. Western blot and qRT-PCR were used to analyze the expression levels of the target protein or mRNA. Apoptosis was observed using the TUNEL assay. The plasma concentrations of CK-MB and cTn-I in humans and mice were determined. RESULTS In the GSE23294 dataset, APOO mRNA was highly expressed in the left ventricle of mice with MI; GSEA revealed that APOO was positively correlated with p38MAPK, autophagy, and apoptosis. The plasma concentration of APOO in patients with MI was significantly higher than that in healthy subjects. The expression of APOO, Beclin-1, LC3, and Bax in mouse and AC16 cell MI models increased, while the level of Bcl-2 decreased. After silencing the APOO gene, the expression of APOO was downregulated; meanwhile, changes in autophagy, apoptosis and myocardial cell injury were reversed in vivo and in vitro. Furthermore, autophagy was alleviated after AC16 cells were treated with SB203580. CONCLUSIONS The increased APOO expression in mouse and cell MI models may activate autophagy and apoptosis by regulating the p38MAPK signaling pathway, thus aggravating the myocardial injury.
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Affiliation(s)
- Yue Liu
- Nanchang University Second Affiliated Hospital, Cardiovascular Medicine, Nanchang City, Jiangxi Province, PR China
| | - Zhiping Xiong
- Nanchang University Second Affiliated Hospital, Cardiovascular Medicine, Nanchang City, Jiangxi Province, PR China
| | - Wei Zhou
- Nanchang University Second Affiliated Hospital, Cardiovascular Medicine, Nanchang City, Jiangxi Province, PR China
| | - Yuxin Chen
- Nanchang University Second Affiliated Hospital, Cardiovascular Medicine, Nanchang City, Jiangxi Province, PR China
| | - Qing Huang
- Nanchang University Second Affiliated Hospital, Cardiovascular Medicine, Nanchang City, Jiangxi Province, PR China
| | - Yanqing Wu
- Nanchang University Second Affiliated Hospital, Cardiovascular Medicine, Nanchang City, Jiangxi Province, PR China.
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12
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Benincá C, Zanette V, Brischigliaro M, Johnson M, Reyes A, Valle DAD, J Robinson A, Degiorgi A, Yeates A, Telles BA, Prudent J, Baruffini E, S F Santos ML, R de Souza RL, Fernandez-Vizarra E, Whitworth AJ, Zeviani M. Mutation in the MICOS subunit gene APOO (MIC26) associated with an X-linked recessive mitochondrial myopathy, lactic acidosis, cognitive impairment and autistic features. J Med Genet 2021; 58:155-167. [PMID: 32439808 PMCID: PMC7116790 DOI: 10.1136/jmedgenet-2020-106861] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/13/2020] [Accepted: 04/12/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND Mitochondria provide ATP through the process of oxidative phosphorylation, physically located in the inner mitochondrial membrane (IMM). The mitochondrial contact site and organising system (MICOS) complex is known as the 'mitoskeleton' due to its role in maintaining IMM architecture. APOO encodes MIC26, a component of MICOS, whose exact function in its maintenance or assembly has still not been completely elucidated. METHODS We have studied a family in which the most affected subject presented progressive developmental delay, lactic acidosis, muscle weakness, hypotonia, weight loss, gastrointestinal and body temperature dysautonomia, repetitive infections, cognitive impairment and autistic behaviour. Other family members showed variable phenotype presentation. Whole exome sequencing was used to screen for pathological variants. Patient-derived skin fibroblasts were used to confirm the pathogenicity of the variant found in APOO. Knockout models in Drosophila melanogaster and Saccharomyces cerevisiae were employed to validate MIC26 involvement in MICOS assembly and mitochondrial function. RESULTS A likely pathogenic c.350T>C transition was found in APOO predicting an I117T substitution in MIC26. The mutation caused impaired processing of the protein during import and faulty insertion into the IMM. This was associated with altered MICOS assembly and cristae junction disruption. The corresponding mutation in MIC26 or complete loss was associated with mitochondrial structural and functional deficiencies in yeast and D. melanogaster models. CONCLUSION This is the first case of pathogenic mutation in APOO, causing altered MICOS assembly and neuromuscular impairment. MIC26 is involved in the assembly or stability of MICOS in humans, yeast and flies.
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Affiliation(s)
- Cristiane Benincá
- Medical Research Council, Mitochondrial Biology Unit, Cambridge, Cambridgeshire, UK
- Department of Genetics, Federal University of Parana, Curitiba, Paraná, Brazil
| | - Vanessa Zanette
- Department of Genetics, Federal University of Parana, Curitiba, Paraná, Brazil
| | | | - Mark Johnson
- Medical Research Council, Mitochondrial Biology Unit, Cambridge, Cambridgeshire, UK
| | - Aurelio Reyes
- Medical Research Council, Mitochondrial Biology Unit, Cambridge, Cambridgeshire, UK
| | | | - Alan J Robinson
- Medical Research Council, Mitochondrial Biology Unit, Cambridge, Cambridgeshire, UK
| | - Andrea Degiorgi
- Department of Chemistry, University of Parma, Parma, Emilia-Romagna, Italy
| | - Anna Yeates
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, Cambridgeshire, UK
| | | | - Julien Prudent
- Medical Research Council, Mitochondrial Biology Unit, Cambridge, Cambridgeshire, UK
| | - Enrico Baruffini
- Department of Chemistry, University of Parma, Parma, Emilia-Romagna, Italy
| | | | | | | | | | - Massimo Zeviani
- Medical Research Council, Mitochondrial Biology Unit, Cambridge, Cambridgeshire, UK
- Department of Neurosciences, University of Padova, Padova, Veneto, Italy
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13
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Anand R, Kondadi AK, Meisterknecht J, Golombek M, Nortmann O, Riedel J, Peifer-Weiß L, Brocke-Ahmadinejad N, Schlütermann D, Stork B, Eichmann TO, Wittig I, Reichert AS. MIC26 and MIC27 cooperate to regulate cardiolipin levels and the landscape of OXPHOS complexes. Life Sci Alliance 2020; 3:e202000711. [PMID: 32788226 PMCID: PMC7425215 DOI: 10.26508/lsa.202000711] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/14/2022] Open
Abstract
Homologous apolipoproteins of MICOS complex, MIC26 and MIC27, show an antagonistic regulation of their protein levels, making it difficult to deduce their individual functions using a single gene deletion. We obtained single and double knockout (DKO) human cells of MIC26 and MIC27 and found that DKO show more concentric onion-like cristae with loss of CJs than any single deletion indicating overlapping roles in formation of CJs. Using a combination of complexome profiling, STED nanoscopy, and blue-native gel electrophoresis, we found that MIC26 and MIC27 are dispensable for the stability and integration of the remaining MICOS subunits into the complex suggesting that they assemble late into the MICOS complex. MIC26 and MIC27 are cooperatively required for the integrity of respiratory chain (super) complexes (RCs/SC) and the F1Fo-ATP synthase complex and integration of F1 subunits into the monomeric F1Fo-ATP synthase. While cardiolipin was reduced in DKO cells, overexpression of cardiolipin synthase in DKO restores the stability of RCs/SC. Overall, we propose that MIC26 and MIC27 are cooperatively required for global integrity and stability of multimeric OXPHOS complexes by modulating cardiolipin levels.
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Affiliation(s)
- Ruchika Anand
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Arun Kumar Kondadi
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Jana Meisterknecht
- Functional Proteomics, Sonderforschungsbereich (SFB) 815 Core Unit, Faculty of Medicine, Goethe-University, Frankfurt am Main, Germany
- Cluster of Excellence "Macromolecular Complexes", Goethe University, Frankfurt am Main, Germany
- German Center of Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt, Germany
| | - Mathias Golombek
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Oliver Nortmann
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Julia Riedel
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Leon Peifer-Weiß
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Nahal Brocke-Ahmadinejad
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - David Schlütermann
- Institute of Molecular Medicine I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Björn Stork
- Institute of Molecular Medicine I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Thomas O Eichmann
- Center for Explorative Lipidomics, BioTechMed-Graz, Graz, Austria
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Ilka Wittig
- Functional Proteomics, Sonderforschungsbereich (SFB) 815 Core Unit, Faculty of Medicine, Goethe-University, Frankfurt am Main, Germany
- Cluster of Excellence "Macromolecular Complexes", Goethe University, Frankfurt am Main, Germany
- German Center of Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt, Germany
| | - Andreas S Reichert
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
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14
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Colina-Tenorio L, Horten P, Pfanner N, Rampelt H. Shaping the mitochondrial inner membrane in health and disease. J Intern Med 2020; 287:645-664. [PMID: 32012363 DOI: 10.1111/joim.13031] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 12/19/2019] [Accepted: 01/20/2020] [Indexed: 12/16/2022]
Abstract
Mitochondria play central roles in cellular energetics, metabolism and signalling. Efficient respiration, mitochondrial quality control, apoptosis and inheritance of mitochondrial DNA depend on the proper architecture of the mitochondrial membranes and a dynamic remodelling of inner membrane cristae. Defects in mitochondrial architecture can result in severe human diseases affecting predominantly the nervous system and the heart. Inner membrane morphology is generated and maintained in particular by the mitochondrial contact site and cristae organizing system (MICOS), the F1 Fo -ATP synthase, the fusion protein OPA1/Mgm1 and the nonbilayer-forming phospholipids cardiolipin and phosphatidylethanolamine. These protein complexes and phospholipids are embedded in a network of functional interactions. They communicate with each other and additional factors, enabling them to balance different aspects of cristae biogenesis and to dynamically remodel the inner mitochondrial membrane. Genetic alterations disturbing these membrane-shaping factors can lead to human pathologies including fatal encephalopathy, dominant optic atrophy, Leigh syndrome, Parkinson's disease and Barth syndrome.
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Affiliation(s)
- L Colina-Tenorio
- From the, Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - P Horten
- From the, Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - N Pfanner
- From the, Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - H Rampelt
- From the, Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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15
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Szostaczuk N, van Schothorst EM, Sánchez J, Priego T, Palou M, Bekkenkamp-Grovenstein M, Faustmann G, Obermayer-Pietsch B, Tiran B, Roob JM, Winklhofer-Roob BM, Keijer J, Palou A, Picó C. Identification of blood cell transcriptome-based biomarkers in adulthood predictive of increased risk to develop metabolic disorders using early life intervention rat models. FASEB J 2020; 34:9003-9017. [PMID: 32474969 DOI: 10.1096/fj.202000071rr] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 12/20/2022]
Abstract
Calorie restriction during gestation in rats has long-lasting adverse effects in the offspring. It induces metabolic syndrome-related alterations, which are partially reversed by leptin supplementation during lactation. We employed these conditions to identify transcript-based nutrient sensitive biomarkers in peripheral blood mononuclear cells (PBMCs) predictive of later adverse metabolic health. The best candidate was validated in humans. Transcriptome analysis of PBMCs from adult male Wistar rats of three experimental groups was performed: offspring of control dams (CON), and offspring of 20% calorie-restricted dams during gestation without (CR) and with leptin supplementation throughout lactation (CR-LEP). The expression of 401 genes was affected by gestational calorie restriction and reversed by leptin. The changes preceded metabolic syndrome-related phenotypic alterations. Of these genes, Npc1 mRNA levels were lower in CR vs CON, and normalized to CON in CR-LEP. In humans, NPC1 mRNA levels in peripheral blood cells (PBCs) were decreased in subjects with mildly impaired metabolic health compared to healthy subjects. Therefore, a set of potential transcript-based biomarkers indicative of a predisposition to metabolic syndrome-related alterations were identified, including NPC1, which was validated in humans. Low NPC1 transcript levels in PBCs are a candidate biomarker of increased risk for impaired metabolic health in humans.
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Affiliation(s)
- Nara Szostaczuk
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Group of Nutrigenomics and Obesity), CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), University of the Balearic Islands, Palma de Mallorca, Spain
| | | | - Juana Sánchez
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Group of Nutrigenomics and Obesity), CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), University of the Balearic Islands, Palma de Mallorca, Spain.,Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Teresa Priego
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Group of Nutrigenomics and Obesity), CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), University of the Balearic Islands, Palma de Mallorca, Spain
| | - Mariona Palou
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Group of Nutrigenomics and Obesity), CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), University of the Balearic Islands, Palma de Mallorca, Spain.,Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | | | - Gernot Faustmann
- Human Nutrition & Metabolism Research and Training Center, Institute of Molecular Biosciences, Karl-Franzens University of Graz, Graz, Austria.,Clinical Division of Nephrology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Barbara Obermayer-Pietsch
- Division of Endocrinology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Beate Tiran
- Clinical Institute of Medical and Clinical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Johannes M Roob
- Clinical Division of Nephrology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Brigitte M Winklhofer-Roob
- Human Nutrition & Metabolism Research and Training Center, Institute of Molecular Biosciences, Karl-Franzens University of Graz, Graz, Austria
| | - Jaap Keijer
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | - Andreu Palou
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Group of Nutrigenomics and Obesity), CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), University of the Balearic Islands, Palma de Mallorca, Spain.,Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Catalina Picó
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Group of Nutrigenomics and Obesity), CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), University of the Balearic Islands, Palma de Mallorca, Spain.,Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
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16
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Transcriptome signatures in the brain of a migratory songbird. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2020; 34:100681. [PMID: 32222683 DOI: 10.1016/j.cbd.2020.100681] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/06/2020] [Accepted: 03/15/2020] [Indexed: 12/22/2022]
Abstract
Most of the birds's adaptations for migration have a neuroendocrine origin, triggered by changes in photoperiod and the patterns of Earth's magnetic field. Migration phenomenology has been well described in the past decades, yet the genetic structure behind it remains terra incognita. We used RNA-Seq data to investigate which biological functions are linked with the seasonal brain adaptations of a long-distance trans-continental migratory passerine, the Northern Wheatear (Oenanthe oenanthe). We sequenced the wheatear's transcriptomes at three different stages: lean birds, a characteristic phenotype before the onset of migration, during fattening, and at their maximal migratory body mass. We identified a total of 15,357 genes in the brain of wheatears, of which 84 were differentially expressed. These were mostly related to nervous tissue development, angiogenesis, ATP production, innate immune response, and antioxidant protection, as well as GABA and dopamine signalling. The expression pattern of differentially expressed genes is correlated with typical phenotypic changes before migration, such as hyperphagia, migratory restlessness, and a potential increment in the visual and spatial memory capacities. Our work points out, for future studies, biological functions found to be involved in the development of the migratory phenotype -a unique model to study the core of neural, energetic and muscular adaptations for endurance exercise. Comparison of wheatears' transcriptomic data with two other studies with similar goals shows no correlation among the trends in the gene expression. It highlights the complexity and diversity of adaptations for long-distance migration in birds.
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17
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Su X, Peng D. The exchangeable apolipoproteins in lipid metabolism and obesity. Clin Chim Acta 2020; 503:128-135. [PMID: 31981585 DOI: 10.1016/j.cca.2020.01.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/15/2020] [Accepted: 01/17/2020] [Indexed: 12/29/2022]
Abstract
Dyslipidemia, characterized by increased plasma levels of low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), triglyceride (TG), and reduced plasma levels of high-density lipoprotein cholesterol (HDL-C), is confirmed as a hallmark of obesity and cardiovascular diseases (CVD), posing serious risks to the future health of humans. Thus, it is important to understand the molecular metabolism of dyslipidemia, which could help reduce the morbidity and mortality of obesity and CVD. Currently, several exchangeable apolipoproteins, such as apolipoprotein A1 (ApoA1), apolipoprotein A5 (ApoA5), apolipoprotein E (ApoE), and apolipoprotein C3 (ApoC3), have been verified to exert vital effects on modulating lipid metabolism and homeostasis both in plasma and in cells, which consequently affect dyslipidemia. In the present review, we summarize the findings of the effect of exchangeable apolipoproteins on affecting lipid metabolism in adipocytes and hepatocytes. Furthermore, we also provide new insights into the mechanisms by which the exchangeable apolipoproteins influence the pathogenesis of dyslipidemia and its related cardio-metabolic disorders.
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Affiliation(s)
- Xin Su
- Department of Cardiovascular Medicine, the Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Daoquan Peng
- Department of Cardiovascular Medicine, the Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
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18
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Fan J, Campioli E, Sottas C, Zirkin B, Papadopoulos V. Amhr2-Cre-Mediated Global Tspo Knockout. J Endocr Soc 2020; 4:bvaa001. [PMID: 32099945 PMCID: PMC7031085 DOI: 10.1210/jendso/bvaa001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/09/2020] [Indexed: 12/27/2022] Open
Abstract
Although the role of translocator protein (TSPO) in cholesterol transport in steroid-synthesizing cells has been studied extensively, recent studies of TSPO genetic depletion have questioned its role. Amhr2-Cre mice have been used to generate Leydig cell-specific Tspo conditional knockout (cKO) mice. Using the same Cre line, we were unable to generate Tspo cKO mice possibly because of genetic linkage between Tspo and Amhr2 and coexpression of Amhr2-Cre and Tspo in early embryonic development. We found that Amhr2-Cre is expressed during preimplantation stages, resulting in global heterozygous mice (gHE; Amhr2-Cre+/–,Tspo–/+). Two gHE mice were crossed, generating Amhr2-Cre–mediated Tspo global knockout (gKO; Tspo–/–) mice. We found that 33.3% of blastocysts at E3.5 to E4.5 showed normal morphology, whereas 66.7% showed delayed development, which correlates with the expected Mendelian proportions of Tspo+/+ (25%), Tspo–/– (25%), and Tspo+/– (50%) genotypes from crossing 2 Tspo–/+ mice. Adult Tspo gKO mice exhibited disturbances in neutral lipid homeostasis and reduced intratesticular and circulating testosterone levels, but no change in circulating basal corticosterone levels. RNA-sequencing data from mouse adrenal glands and lungs revealed transcriptome changes in response to the loss of TSPO, including changes in several cholesterol-binding and transfer proteins. This study demonstrates that Amhr2-Cre can be used to produce Tspo gKO mice instead of cKO, and can serve as a new global “Cre deleter.” Moreover, our results show that Tspo deletion causes delayed preimplantation embryonic development, alters neutral lipid storage and steroidogenesis, and leads to transcriptome changes that may reflect compensatory mechanisms in response to the loss of function of TSPO.
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Affiliation(s)
- Jinjiang Fan
- The Research Institute of the McGill University Health Centre.,Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Enrico Campioli
- The Research Institute of the McGill University Health Centre.,Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Chantal Sottas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, US
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, US
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, US
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19
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Abstract
The apolipoproteins are well known for their roles in both health and disease, as components of plasma lipoprotein particles, such as high-density lipoprotein (HDL), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), chylomicrons, and metabolic, vascular- and inflammation-related disorders, such as cardiovascular disease, atherosclerosis, metabolic syndrome, and diabetes. Increasingly, their roles in neurovascular and neurodegenerative disorders are also being elucidated. They play major roles in lipid and cholesterol transport between blood and organs and are, therefore, critical to maintenance and homeostasis of the lipidome, with apolipoprotein-lipid interactions, including cholesterol, fatty acids, triglycerides, phospholipids, and isoprostanes. Further, they have important pleiotropic roles related to aging and longevity, which are largely managed through their many structural variants, including multiple isoforms, and a diversity of post-translational modifications. Consequently, tools for the characterization and accurate quantification of apolipoproteins, including their diverse array of variant forms, are required to understand their salutary and disease related roles. In this chapter we outline three distinct quantitative approaches suitable for targeting apolipoproteins: (1) multiplex immunoassays, (2) mass spectrometric immunoassay, and (3) multiple reaction monitoring, mass spectrometric quantification. We also discuss management of pre-analytical and experimental design variables.
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20
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Eramo MJ, Lisnyak V, Formosa LE, Ryan MT. The ‘mitochondrial contact site and cristae organising system’ (MICOS) in health and human disease. J Biochem 2019; 167:243-255. [DOI: 10.1093/jb/mvz111] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 12/05/2019] [Indexed: 12/14/2022] Open
Abstract
AbstractThe ‘mitochondrial contact site and cristae organising system’ (MICOS) is an essential protein complex that promotes the formation, maintenance and stability of mitochondrial cristae. As such, loss of core MICOS components disrupts cristae structure and impairs mitochondrial function. Aberrant mitochondrial cristae morphology and diminished mitochondrial function is a pathological hallmark observed across many human diseases such as neurodegenerative conditions, obesity and diabetes mellitus, cardiomyopathy, and in muscular dystrophies and myopathies. While mitochondrial abnormalities are often an associated secondary effect to the pathological disease process, a direct role for the MICOS in health and human disease is emerging. This review describes the role of MICOS in the maintenance of mitochondrial architecture and summarizes both the direct and associated roles of the MICOS in human disease.
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Affiliation(s)
- Matthew J Eramo
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, 23 Innovation Walk, Monash University, 3800 Melbourne, Victoria, Australia
| | - Valerie Lisnyak
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, 23 Innovation Walk, Monash University, 3800 Melbourne, Victoria, Australia
| | - Luke E Formosa
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, 23 Innovation Walk, Monash University, 3800 Melbourne, Victoria, Australia
| | - Michael T Ryan
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, 23 Innovation Walk, Monash University, 3800 Melbourne, Victoria, Australia
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21
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Montasser ME, O’Hare EA, Wang X, Howard AD, McFarland R, Perry JA, Ryan KA, Rice K, Jaquish CE, Shuldiner AR, Miller M, Mitchell BD, Zaghloul NA, Chang YPC. An APOO Pseudogene on Chromosome 5q Is Associated With Low-Density Lipoprotein Cholesterol Levels. Circulation 2018; 138:1343-1355. [PMID: 29593015 PMCID: PMC6162188 DOI: 10.1161/circulationaha.118.034016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 03/19/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND Elevated levels of low-density lipoprotein cholesterol (LDL-C) are a major risk factor for cardiovascular disease via its contribution to the development and progression of atherosclerotic lesions. Although the genetic basis of LDL-C has been studied extensively, currently known genetic variants account for only ≈20% of the variation in LDL-C levels. METHODS Through an array-based association analysis in 1102 Amish subjects, we identified a variant strongly associated with LDL-C levels. Using a combination of genetic analyses, zebrafish models, and in vitro experiments, we sought to identify the causal gene driving this association. RESULTS We identified a founder haplotype associated with a 15 mg/dL increase in LDL-C on chromosome 5. After recombination mapping, the associated region contained 8 candidate genes. Using a zebrafish model to evaluate the relevance of these genes to cholesterol metabolism, we found that expression of the transcribed pseudogene, APOOP1, increased LDL-C and vascular plaque formation. CONCLUSIONS Based on these data, we propose that APOOP1 regulates levels of LDL-C in humans, thus identifying a novel mechanism of lipid homeostasis.
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Affiliation(s)
- May E. Montasser
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Elizabeth A. O’Hare
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Xiaochun Wang
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Alicia D. Howard
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Rebecca McFarland
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - James A. Perry
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Kathleen A. Ryan
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Kenneth Rice
- Dept of Biostatistics, University of Washington, Seattle, WA
| | | | - Alan R. Shuldiner
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Michael Miller
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Braxton D. Mitchell
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
- Geriatrics Research and Education Clinical Center, Baltimore Veterans Administration Medical Center, Baltimore, MD, USA
| | - Norann A. Zaghloul
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Yen-Pei C. Chang
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
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22
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Pei J, Kinch LN, Grishin NV. FlyXCDB—A Resource for Drosophila Cell Surface and Secreted Proteins and Their Extracellular Domains. J Mol Biol 2018; 430:3353-3411. [DOI: 10.1016/j.jmb.2018.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 05/31/2018] [Accepted: 06/02/2018] [Indexed: 02/06/2023]
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23
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Weijler AM, Schmidinger B, Kapiotis S, Laggner H, Hermann M. Oleic acid induces the novel apolipoprotein O and reduces mitochondrial membrane potential in chicken and human hepatoma cells. Biochimie 2018; 147:136-142. [PMID: 29432786 DOI: 10.1016/j.biochi.2018.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 02/05/2018] [Indexed: 12/28/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is marked by hepatic fat accumulation and reflects a spectrum of chronic liver diseases associated with obesity, impaired insulin sensitivity and dyslipidemia. Apolipoprotein O (ApoO) is a new member of the plasma apolipoprotein family that may play a role in lipid metabolism and electron transport activity of the mitochondrium. However, its physiological functions have not been elucidated yet. Based on our previous data in a non-mammalian experimental system [1], we hypothesized that hepatic expression of ApoO is tightly linked not only to diet-induced hepatosteatosis, but also to increased lipoprotein-production induced by, e.g., hormones and oxidative stress. To gain insight into a mammalian experimental system, we compared the effects of lipid loading on ApoO regulation in chicken hepatoma LMH cells with those in the human hepatoma cell line HepG2. Incubation of the cells with BSA-complexed oleic acid (OA-Alb) induced triglyceride accumulation, but did not affect cell viability. qPCR using specific primer pairs and Western blot analysis with in-house produced rabbit anti-ApoO antisera demonstrated significant increase in ApoO transcript and protein levels in both cell lines. ROS formation due to OA-Alb treatment was only slightly altered in LMH cells, indicating an intact antioxidant defense system of the cells. Oxidative stress applied by addition of H2O2 revealed induction of ApoO transcript and protein level in the same or even higher extent as monitored in the presence of OA-Alb. Upon treatment with estrogen for 24 h quantitative analysis of ApoO transcript and protein revealed increases of ApoO expression supporting the assumption that estrogen affects lipoprotein metabolism at various points. Furthermore, both cell lines showed a significant decrease of the mitochondrial membrane potential upon incubation with OA-Alb. Therefore, we assume that our findings support a role of ApoO as an effector of compromised mitochondrial function that likely accompanies the onset of non-alcoholic fatty liver disease.
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Affiliation(s)
- Anna M Weijler
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Barbara Schmidinger
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Stylianos Kapiotis
- The Central Laboratory, Hospital of the Divine Redeemer, Vienna, Austria
| | - Hilde Laggner
- Department of Medical Chemistry and Pathobiochemistry, Center of Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Marcela Hermann
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria.
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24
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Liu L, Cui H, Fu R, Zheng M, Liu R, Zhao G, Wen J. The regulation of IMF deposition in pectoralis major of fast- and slow- growing chickens at hatching. J Anim Sci Biotechnol 2017; 8:77. [PMID: 29026539 PMCID: PMC5623058 DOI: 10.1186/s40104-017-0207-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/22/2017] [Indexed: 12/18/2022] Open
Abstract
Background The lipid from egg yolk is largely consumed in supplying the energy for embryonic growth until hatching. The remaining lipid in the yolk sac is transported into the hatchling’s tissues. The gene expression profiles of fast- and slow-growing chickens, Arbor Acres (AA) and Beijing-You (BJY), were determined to identify global differentially expressed genes and enriched pathways related to lipid metabolism in the pectoralis major at hatching. Results Between these two breeds, the absolute and weight-specific amounts of total yolk energy (TYE) and intramuscular fat (IMF) content in pectoralis major of fast-growing chickens were significantly higher (P < 0.01, P < 0.01, P < 0.05, respectively) than those of the slow-growing breed. IMF content and u-TYE were significantly related (r = 0.9047, P < 0.01). Microarray analysis revealed that gene transcripts related to lipogenesis, including PPARG, RBP7, LPL, FABP4, THRSP, ACACA, ACSS1, DGAT2, and GK, were significantly more abundant in breast muscle of fast-growing chickens than in slow-growing chickens. Conversely, the abundance of transcripts of genes involved in fatty acid degradation and glycometabolism, including ACAT1, ACOX2, ACOX3, CPT1A, CPT2, DAK, APOO, FUT9, GCNT1, and B4GALT3, was significantly lower in fast-growing chickens. The results further indicated that the PPAR signaling pathway was directly involved in fat deposition in pectoralis major, and other upstream pathways (Hedgehog, TGF-beta, and cytokine–cytokine receptor interaction signaling pathways) play roles in its regulation of the expression of related genes. Conclusions Additional energy from the yolk sac is transported and deposited as IMF in the pectoralis major of chickens at hatching. Genes and pathways related to lipid metabolism (such as PPAR, Hedgehog, TGF-beta, and cytokine–cytokine receptor interaction signaling pathways) promote the deposition of IMF in the pectoralis major of fast-growing chickens compared with those that grow more slowly. These findings provide new insights into the molecular mechanisms underlying lipid metabolism and deposition in hatchling chickens. Electronic supplementary material The online version of this article (10.1186/s40104-017-0207-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lu Liu
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.,State Key Laboratory of Animal Nutrition, Beijing, 100193 China
| | - Huanxian Cui
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.,State Key Laboratory of Animal Nutrition, Beijing, 100193 China
| | - Ruiqi Fu
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.,State Key Laboratory of Animal Nutrition, Beijing, 100193 China
| | - Maiqing Zheng
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.,State Key Laboratory of Animal Nutrition, Beijing, 100193 China
| | - Ranran Liu
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.,State Key Laboratory of Animal Nutrition, Beijing, 100193 China
| | - Guiping Zhao
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.,State Key Laboratory of Animal Nutrition, Beijing, 100193 China
| | - Jie Wen
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.,State Key Laboratory of Animal Nutrition, Beijing, 100193 China
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25
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Tian F, Wu CL, Yu BL, Liu L, Hu JR. Apolipoprotein O expression in mouse liver enhances hepatic lipid accumulation by impairing mitochondrial function. Biochem Biophys Res Commun 2017. [PMID: 28647361 DOI: 10.1016/j.bbrc.2017.06.128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Apolipoprotein O (ApoO) was recently observed in the cellular mitochondrial inner membrane, which plays a role in mitochondrial function and is associated with myocardiopathy. Empirical information on the physiological functions of apoO is therefore limited. In this study, we aimed to elucidate the effect of apoO on hepatic fatty acid metabolism. An adenoviral vector expressing hApoO was constructed and introduced into chow diet and high-fat diet induced mice and the L02 human hepatoma cell line. High levels of hApoO mRNA and protein were detected in the liver, and the expression of lipid metabolism genes was significantly altered compared with negative controls. The liver function indices (serum ALT and AST) were clearly elevated, and the ultrastructure of cellular mitochondria was distinctly altered in the liver after apoO overexpression. Further, mitochondrial membrane potential decreased with hApoO treatment in L02 cells. These results establish a link between apoO and lipid accumulation and could suggest a new pathway for regulating non-alcoholic fatty liver disease progression.
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Affiliation(s)
- Feng Tian
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Chen-Lu Wu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Bi-Lian Yu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Ling Liu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Jia-Rui Hu
- Department of Spine Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China.
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26
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Abstract
The heart utilizes large amounts of fatty acids as energy providing substrates. The physiological balance of lipid uptake and oxidation prevents accumulation of excess lipids. Several processes that affect cardiac function, including ischemia, obesity, diabetes mellitus, sepsis, and most forms of heart failure lead to altered fatty acid oxidation and often also to the accumulation of lipids. There is now mounting evidence associating certain species of these lipids with cardiac lipotoxicity and subsequent myocardial dysfunction. Experimental and clinical data are discussed and paths to reduction of toxic lipids as a means to improve cardiac function are suggested.
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Affiliation(s)
- P Christian Schulze
- From the Divisions of Cardiology, Friedrich-Schiller-University Jena, Germany, and Columbia University, New York, NY (P.C.S.); Metabolic Biology Laboratory, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.D.); and Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY (I.J.G.).
| | - Konstantinos Drosatos
- From the Divisions of Cardiology, Friedrich-Schiller-University Jena, Germany, and Columbia University, New York, NY (P.C.S.); Metabolic Biology Laboratory, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.D.); and Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY (I.J.G.)
| | - Ira J Goldberg
- From the Divisions of Cardiology, Friedrich-Schiller-University Jena, Germany, and Columbia University, New York, NY (P.C.S.); Metabolic Biology Laboratory, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.D.); and Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY (I.J.G.)
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27
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Rampelt H, Zerbes RM, van der Laan M, Pfanner N. Role of the mitochondrial contact site and cristae organizing system in membrane architecture and dynamics. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:737-746. [DOI: 10.1016/j.bbamcr.2016.05.020] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/12/2016] [Accepted: 05/17/2016] [Indexed: 12/22/2022]
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28
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White CR, Datta G, Giordano S. High-Density Lipoprotein Regulation of Mitochondrial Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:407-429. [PMID: 28551800 DOI: 10.1007/978-3-319-55330-6_22] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Lipoproteins play a key role in regulating plasma and tissue levels of cholesterol. Apolipoprotein B (apoB)-containing lipoproteins, including chylomicrons, very-low density lipoprotein (VLDL) and low-density lipoprotein (LDL), serve as carriers of triglycerides and cholesterol and deliver these metabolites to peripheral tissues. In contrast, high-density lipoprotein (HDL) mediates Reverse Cholesterol Transport (RCT), a process by which excess cholesterol is removed from the periphery and taken up by hepatocytes where it is metabolized and excreted. Anti-atherogenic properties of HDL have been largely ascribed to apoA-I, the major protein component of the lipoprotein particle. The inflammatory response associated with atherosclerosis and ischemia-reperfusion (I-R) injury has been linked to the development of mitochondrial dysfunction. Under these conditions, an increase in reactive oxygen species (ROS) formation induces damage to mitochondrial structural elements, leading to a reduction in ATP synthesis and initiation of the apoptotic program. Recent studies suggest that HDL-associated apoA-I and lysosphingolipids attenuate mitochondrial injury by multiple mechanisms, including the suppression of ROS formation and induction of autophagy. Other apolipoproteins, however, present in lower abundance in HDL particles may exert opposing effects on mitochondrial function. This chapter examines the role of HDL-associated apolipoproteins and lipids in the regulation of mitochondrial function and bioenergetics.
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Affiliation(s)
- C Roger White
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Geeta Datta
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Samantha Giordano
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA.
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29
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Anand R, Strecker V, Urbach J, Wittig I, Reichert AS. Mic13 Is Essential for Formation of Crista Junctions in Mammalian Cells. PLoS One 2016; 11:e0160258. [PMID: 27479602 PMCID: PMC4968808 DOI: 10.1371/journal.pone.0160258] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/15/2016] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial cristae are connected to the inner boundary membrane via crista junctions which are implicated in the regulation of oxidative phosphorylation, apoptosis, and import of lipids and proteins. The MICOS complex determines formation of crista junctions. We performed complexome profiling and identified Mic13, also termed Qil1, as a subunit of the MICOS complex. We show that MIC13 is an inner membrane protein physically interacting with MIC60, a central subunit of the MICOS complex. Using the CRISPR/Cas method we generated the first cell line deleted for MIC13. These knockout cells show a complete loss of crista junctions demonstrating that MIC13 is strictly required for the formation of crista junctions. MIC13 is required for the assembly of MIC10, MIC26, and MIC27 into the MICOS complex. However, it is not needed for the formation of the MIC60/MIC19/MIC25 subcomplex suggesting that the latter is not sufficient for crista junction formation. MIC13 is also dispensable for assembly of respiratory chain complexes and for maintaining mitochondrial network morphology. Still, lack of MIC13 resulted in a moderate reduction of mitochondrial respiration. In summary, we show that MIC13 has a fundamental role in crista junction formation and that assembly of respiratory chain supercomplexes is independent of mitochondrial cristae shape.
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Affiliation(s)
- Ruchika Anand
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University, Medical Faculty, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Valentina Strecker
- Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine, Goethe-University, Frankfurt am Main, Germany
| | - Jennifer Urbach
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University, Medical Faculty, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Ilka Wittig
- Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine, Goethe-University, Frankfurt am Main, Germany
- Cluster of Excellence “Macromolecular Complexes”, Goethe University, Frankfurt am Main, Germany
- German Center of Cardiovascular Research (DZHK), Partner site RheinMain, Frankfurt, Germany
| | - Andreas S. Reichert
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University, Medical Faculty, Universitätsstr. 1, 40225, Düsseldorf, Germany
- * E-mail:
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30
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Schmidinger B, Weijler AM, Schneider WJ, Hermann M. Hepatosteatosis and estrogen increase apolipoprotein O production in the chicken. Biochimie 2016; 127:37-43. [PMID: 27126072 DOI: 10.1016/j.biochi.2016.04.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/21/2016] [Indexed: 10/21/2022]
Abstract
Apolipoprotein O (ApoO) is a recently discovered plasma apolipoprotein that may also play a role in the mitochondrial inner membrane. Possibly due to this complexity, its physiological functions have not been elucidated yet. To gain insight from a non-mammalian experimental system, we have investigated the regulation of ApoO levels in an alternative, well-suited model for studies on lipid metabolism, the chicken. qPCR using specific primer pairs and Western blot analysis with our rabbit anti-chicken ApoO antiserum demonstrated ApoO in the liver of chickens fed a control or a fat-enriched diet, as well as in 2 chicken hepatoma cell lines, LMH cells and the estrogen-responsive LMH-2A cells, under conditions of lipid loading by incubation with BSA-complexed oleic acid. Induced triglyceride accumulation in both the liver and the hepatic cells was associated with significantly increased levels of ApoO mRNA and protein. Furthermore, upon treatment for 24 h with estrogen of the estrogen receptor-expressing LMH-2A cells, quantitative analysis of ApoO transcripts and Western blotting revealed increases of ApoO expression. Finally, upon a single administration of estrogen to roosters that leads to hyperlipidemia, higher hepatic levels of both ApoO transcript and protein were observed within 24 h. Based on these data, we propose that hepatic expression of ApoO is tightly linked not only to diet-induced hepatosteatosis, but also to increased lipoprotein-production induced by, e.g., hormones. The findings support a role of ApoO as an effector of compromised mitochondrial function that likely accompanies the onset of non-alcoholic fatty liver disease.
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Affiliation(s)
- Barbara Schmidinger
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Anna M Weijler
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Wolfgang J Schneider
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Marcela Hermann
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria.
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31
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O'Connell GC, Nichols C, Guo G, Croston TL, Thapa D, Hollander JM, Pistilli EE. IL-15Rα deficiency in skeletal muscle alters respiratory function and the proteome of mitochondrial subpopulations independent of changes to the mitochondrial genome. Mitochondrion 2015; 25:87-97. [PMID: 26458787 DOI: 10.1016/j.mito.2015.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/24/2015] [Accepted: 10/05/2015] [Indexed: 10/22/2022]
Abstract
Interleukin-15 receptor alpha knockout (IL15RαKO) mice exhibit a greater skeletal muscle mitochondrial density with an altered mitochondrial morphology. However, the mechanism and functional impact of these changes have not been determined. In this study, we characterized the functional, proteomic, and genomic alterations in mitochondrial subpopulations isolated from the skeletal muscles of IL15RαKO mice and B6129 background control mice. State 3 respiration was greater in interfibrillar mitochondria and whole muscle ATP levels were greater in IL15RαKO mice supporting the increases in respiration rate. However, the state 3/state 4 ratio was lower, suggesting some degree of respiratory uncoupling. Proteomic analyses identified several markers independently in mitochondrial subpopulations that are associated with these functional alterations. Next Generation Sequencing of mtDNA revealed a high degree of similarity between the mitochondrial genomes of IL15RαKO mice and controls in terms of copy number, consensus coding and the presence of minor alleles, suggesting that the functional and proteomic alterations we observed occurred independent of alterations to the mitochondrial genome. These data provide additional evidence to implicate IL-15Rα as a regulator of skeletal muscle phenotypes through effects on the mitochondrion, and suggest these effects are driven by alterations to the mitochondrial proteome.
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Affiliation(s)
| | | | - Ge Guo
- Division of Exercise Physiology, United States
| | | | | | - John M Hollander
- Division of Exercise Physiology, United States; Center for Cardiovascular and Respiratory Sciences, United States
| | - Emidio E Pistilli
- Division of Exercise Physiology, United States; Center for Cardiovascular and Respiratory Sciences, United States; Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV, United States.
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32
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Greene DJ, Izem L, Morton RE. Defective triglyceride biosynthesis in CETP-deficient SW872 cells. J Lipid Res 2015. [PMID: 26203075 DOI: 10.1194/jlr.m056481] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We previously reported that reducing the expression of cholesteryl ester transfer protein (CETP) disrupts cholesterol homeostasis in SW872 cells and causes an ∼50% reduction in TG. The causes of this reduced TG content, investigated here, could not be attributed to changes in the differentiation status of CETP-deficient cells, nor was there evidence of endoplasmic reticulum (ER) stress. In short-term studies, the total flux of oleate through the TG biosynthetic pathway was not altered in CETP-deficient cells, although mRNA levels of some pathway enzymes were different. However, the conversion of diglyceride (DG) to TG was impaired. In longer-term studies, newly synthesized TG was not effectively transported to lipid droplets, yet this lipid did not accumulate in the ER, apparently due to elevated lipase activity in this organelle. DG, shown to be a novel CETP substrate, was also inefficiently transferred to lipid droplets. This may reduce TG synthesis on droplets by resident diacylglycerol acyltransferase. Overall, these data suggest that the decreased TG content of CETP-deficient cells arises from the reduced conversion of DG to TG in the ER and/or on the lipid droplet surface, and enhanced TG degradation in the ER due to its ineffective transport from this organelle.
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Affiliation(s)
- Diane J Greene
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Lahoucine Izem
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Richard E Morton
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
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33
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Koob S, Barrera M, Anand R, Reichert AS. The non-glycosylated isoform of MIC26 is a constituent of the mammalian MICOS complex and promotes formation of crista junctions. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1853:1551-63. [PMID: 25764979 DOI: 10.1016/j.bbamcr.2015.03.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/13/2015] [Accepted: 03/02/2015] [Indexed: 01/05/2023]
Abstract
Mitochondrial membrane architecture is important for organelle function. Alterations thereof are linked to a number of human disorders including diabetes and cardiomyopathy. The MICOS complex was recently reported to be a central player determining cristae structure and formation of crista junctions. Here we investigated the functional role of MIC26, a lipoprotein formerly termed APOO. Its levels are increased in diabetic heart tissue and in blood plasma of patients suffering from acute coronary syndrome. We demonstrate that human MIC26 exists in three distinct forms: (1) a glycosylated and secreted 55kDa protein, (2) an ER/Golgi-resident form thereof, and (3) a non-glycosylated 22kDa mitochondrial protein. The latter isoform spans the mitochondrial inner membrane and physically interacts with several MICOS complex subunits such as MIC60, MIC27, and MIC10. We further demonstrate that MIC26 and MIC27, a homologous protein formerly termed APOOL, regulate their levels in an antagonistic manner. Both proteins are positively correlated with the levels of MIC10 as well as tafazzin, an enzyme required for cardiolipin remodeling. Overexpression of MIC26 induced fragmentation of mitochondria, promoted ROS formation and resulted in impaired mitochondrial respiration. Downregulation of MIC26 induced a decrease in mitochondrial oxygen consumption, whereas mitochondrial network morphology and ROS levels remained unaffected. MIC26 depletion led to alterations in mitochondrial ultrastructure and caused a significant reduction in the number of crista junctions. In summary, we show that the human apolipoprotein MIC26 is a bona fide subunit of the MICOS complex and that MIC26 is linked to cardiolipin metabolism and promotes crista junction formation.
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Affiliation(s)
- Sebastian Koob
- Mitochondrial Biology, Buchmann Institute of Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Miguel Barrera
- Mitochondrial Biology, Buchmann Institute of Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Ruchika Anand
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University, Medical Faculty, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Andreas S Reichert
- Mitochondrial Biology, Buchmann Institute of Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany; Institute of Biochemistry and Molecular Biology I, Heinrich Heine University, Medical Faculty, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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Sung MM, Hamza SM, Dyck JRB. Myocardial metabolism in diabetic cardiomyopathy: potential therapeutic targets. Antioxid Redox Signal 2015; 22:1606-30. [PMID: 25808033 DOI: 10.1089/ars.2015.6305] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Cardiovascular complications in diabetes are particularly serious and represent the primary cause of morbidity and mortality in diabetic patients. Despite early observations of cardiac dysfunction in diabetic humans, cardiomyopathy unique to diabetes has only recently been recognized. RECENT ADVANCES Research has focused on understanding the pathogenic mechanisms underlying the initiation and development of diabetic cardiomyopathy. Emerging data highlight the importance of altered mitochondrial function as a major contributor to cardiac dysfunction in diabetes. Mitochondrial dysfunction occurs by several mechanisms involving altered cardiac substrate metabolism, lipotoxicity, impaired cardiac insulin and glucose homeostasis, impaired cellular and mitochondrial calcium handling, oxidative stress, and mitochondrial uncoupling. CRITICAL ISSUES Currently, treatment is not specifically tailored for diabetic patients with cardiac dysfunction. Given the multifactorial development and progression of diabetic cardiomyopathy, traditional treatments such as anti-diabetic agents, as well as cellular and mitochondrial fatty acid uptake inhibitors aimed at shifting the balance of cardiac metabolism from utilizing fat to glucose may not adequately target all aspects of this condition. Thus, an alternative treatment such as resveratrol, which targets multiple facets of diabetes, may represent a safe and promising supplement to currently recommended clinical therapy and lifestyle changes. FUTURE DIRECTIONS Elucidation of the mechanisms underlying the initiation and progression of diabetic cardiomyopathy is essential for development of effective and targeted treatment strategies. Of particular interest is the investigation of alternative therapies such as resveratrol, which can function as both preventative and mitigating agents in the management of diabetic cardiomyopathy.
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Affiliation(s)
- Miranda M Sung
- Department of Pediatrics, Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
| | - Shereen M Hamza
- Department of Pediatrics, Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
| | - Jason R B Dyck
- Department of Pediatrics, Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
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35
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Zhao X, Gao M, He J, Zou L, Lyu Y, Zhang L, Geng B, Liu G, Xu G. Perilipin1 deficiency in whole body or bone marrow-derived cells attenuates lesions in atherosclerosis-prone mice. PLoS One 2015; 10:e0123738. [PMID: 25855981 PMCID: PMC4391836 DOI: 10.1371/journal.pone.0123738] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 03/05/2015] [Indexed: 02/05/2023] Open
Abstract
Aims The objective of this study is to determine the role of perilipin 1 (Plin1) in whole body or bone marrow-derived cells on atherogenesis. Methods and Results Accumulated evidence have indicated the role of Plin1 in atherosclerosis, however, these findings are controversial. In this study, we showed that Plin1 was assembled and colocalized with CD68 in macrophages in atherosclerotic plaques of ApoE-/- mice. We further found 39% reduction of plaque size in the aortic roots of Plin1 and ApoE double knockout (Plin1-/-ApoE-/-) females compared with ApoE-/- female littermates. In order to verify whether this reduction was macrophage-specific, the bone marrow cells from wild-type or Plin1 deficient mice (Plin1-/-) were transplanted into LDL receptor deficient mice (LDLR-/-). Mice receiving Plin1-/- bone marrow cells showed also 49% reduction in aortic atherosclerotic lesions compared with LDLR-/- mice received wild-type bone marrow cells. In vitro experiments showed that Plin1-/- macrophages had decreased protein expression of CD36 translocase and an enhanced cholesterol ester hydrolysis upon aggregated-LDL loading, with unaltered expression of many other regulators of cholesterol metabolism, such as cellular lipases, and Plin2 and 3. Given the fundamental role of Plin1 in protecting LD lipids from lipase hydrolysis, it is reasonably speculated that the assembly of Plin1 in microphages might function to reduce lipolysis and hence increase lipid retention in ApoE-/- plaques, but this pro-atherosclerotic property would be abrogated on inactivation of Plin1. Conclusion Plin1 deficiency in bone marrow-derived cells may be responsible for reduced atherosclerotic lesions in the mice.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Antigens, Differentiation, Myelomonocytic/genetics
- Antigens, Differentiation, Myelomonocytic/metabolism
- Apolipoproteins E/genetics
- Atherosclerosis/genetics
- Atherosclerosis/metabolism
- Atherosclerosis/pathology
- Bone Marrow Cells/metabolism
- Bone Marrow Cells/pathology
- Bone Marrow Transplantation
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cholesterol Esters/genetics
- Cholesterol Esters/metabolism
- Female
- Humans
- Macrophages/metabolism
- Macrophages/pathology
- Membrane Proteins/metabolism
- Mice
- Mice, Knockout
- Perilipin-1
- Perilipin-2
- Perilipin-3
- Phosphoproteins/deficiency
- Phosphoproteins/genetics
- Phosphoproteins/metabolism
- Plaque, Atherosclerotic/genetics
- Plaque, Atherosclerotic/pathology
- Receptors, LDL/genetics
- Receptors, LDL/metabolism
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Affiliation(s)
- Xiaojing Zhao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Mingming Gao
- The Key Laboratory of Molecular Cardiovascular Sciences, the Ministry of Education, Beijing, China
| | - Jinhan He
- Department of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Liangqiang Zou
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Ying Lyu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Ling Zhang
- The Key Laboratory of Molecular Cardiovascular Sciences, the Ministry of Education, Beijing, China
| | - Bin Geng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
- * E-mail: (GL); (BG)
| | - George Liu
- The Key Laboratory of Molecular Cardiovascular Sciences, the Ministry of Education, Beijing, China
- * E-mail: (GL); (BG)
| | - Guoheng Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
- The Key Laboratory of Molecular Cardiovascular Sciences, the Ministry of Education, Beijing, China
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36
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Kamper M, Manns CC, Plieschnig JA, Schneider WJ, Ivessa NE, Hermann M. Estrogen enhances secretion of apolipoprotein B-100 containing lipoproteins by BeWo cells. Biochimie 2015; 112:121-8. [PMID: 25765953 DOI: 10.1016/j.biochi.2015.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 03/02/2015] [Indexed: 01/03/2023]
Abstract
Although the early human embryo is capable of covering its cholesterol demand by endogenous synthesis, during later stages of development the fetus may become dependent on transplacental cholesterol transport. On one hand, this conclusion is based on the severe developmental abnormalities of embryos with mutations in the gene specifying the enzyme catalyzing the last step of cholesterol synthesis, 7-dehydrocholesterol reductase, causing Smith-Lemli-Opitz Syndrome. On the other hand, increased total maternal plasma cholesterol levels may reflect the requirement by the growing fetus and/or the placenta for cholesterol. Various molecules and complexes must cross the placental barrier consisting of trophoblasts and fetal endothelial cells to reach the fetal circulation. The de novo synthesis of apolipoprotein B (apoB)-containing lipoproteins coupled to secretion from trophoblasts towards the fetal side is one efficient pathway for cholesterol supply. ApoB and the microsomal triglyceride transfer protein (MTP) are essential components for the assembly of apoB-containing lipoproteins. The aim of this study was to evaluate functional properties of the human placental cell line BeWo as an in vitro model for placental synthesis of apoB-containing lipoproteins by focusing on components required for lipoprotein assembly and secretion. We demonstrate mRNA and protein production of apoB-100, MTP, and protein disulfide isomerase (PDI) in BeWo cells. In addition, metabolic radiolabeling and apoB-immunoprecipitation of cell extracts and media revealed that synthesis and secretion of apoB-containing lipoproteins are enhanced by estrogen. The expression of apoB-100, MTP, and PDI, and the estrogen-stimulated lipoprotein secretion by BeWo cells suggest that these cells are a useful system to study aspects of lipoprotein metabolism at the placental barrier.
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Affiliation(s)
- Miriam Kamper
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Clara C Manns
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Julia A Plieschnig
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Wolfgang J Schneider
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - N Erwin Ivessa
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Marcela Hermann
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria.
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37
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Izem L, Greene DJ, Bialkowska K, Morton RE. Overexpression of full-length cholesteryl ester transfer protein in SW872 cells reduces lipid accumulation. J Lipid Res 2015; 56:515-525. [PMID: 25593327 DOI: 10.1194/jlr.m053678] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cells produce two cholesteryl ester transfer protein (CETP) isoforms, full-length and a shorter variant produced by alternative splicing. Blocking synthesis of both isoforms disrupts lipid metabolism and storage. To further define the role of CETP in cellular lipid metabolism, we stably overexpressed full-length CETP in SW872 cells. These CETP(+) cells had several-fold higher intracellular CETP and accumulated 50% less TG due to a 26% decrease in TG synthesis and 2.5-fold higher TG turnover rate. Reduced TG synthesis was due to decreased fatty acid uptake and impaired conversion of diglyceride to TG even though diacylglycerol acyltransferase activity was normal. Sterol-regulatory element binding protein 1 mRNA levels were normal, and although PPARγ expression was reduced, the expression of several of its target genes including adipocyte triglyceride lipase, FASN, and APOE was normal. CETP(+) cells contained smaller lipid droplets, consistent with their higher levels of perilipin protein family (PLIN) 3 compared with PLIN1 and PLIN2. Intracellular CETP was mostly associated with the endoplasmic reticulum, although CETP near lipid droplets poorly colocalized with this membrane. A small pool of CETP resided in the cytoplasm, and a subfraction coisolated with lipid droplets. These data show that overexpression of full-length CETP disrupts lipid homeostasis resulting in the formation of smaller, more metabolically active lipid droplets.
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Affiliation(s)
- Lahoucine Izem
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Diane J Greene
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Katarzyna Bialkowska
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Richard E Morton
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195.
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38
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Kontush A, Lindahl M, Lhomme M, Calabresi L, Chapman MJ, Davidson WS. Structure of HDL: particle subclasses and molecular components. Handb Exp Pharmacol 2015; 224:3-51. [PMID: 25522985 DOI: 10.1007/978-3-319-09665-0_1] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
A molecular understanding of high-density lipoprotein (HDL) will allow a more complete grasp of its interactions with key plasma remodelling factors and with cell-surface proteins that mediate HDL assembly and clearance. However, these particles are notoriously heterogeneous in terms of almost every physical, chemical and biological property. Furthermore, HDL particles have not lent themselves to high-resolution structural study through mainstream techniques like nuclear magnetic resonance and X-ray crystallography; investigators have therefore had to use a series of lower resolution methods to derive a general structural understanding of these enigmatic particles. This chapter reviews current knowledge of the composition, structure and heterogeneity of human plasma HDL. The multifaceted composition of the HDL proteome, the multiple major protein isoforms involving translational and posttranslational modifications, the rapidly expanding knowledge of the HDL lipidome, the highly complex world of HDL subclasses and putative models of HDL particle structure are extensively discussed. A brief history of structural studies of both plasma-derived and recombinant forms of HDL is presented with a focus on detailed structural models that have been derived from a range of techniques spanning mass spectrometry to molecular dynamics.
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Affiliation(s)
- Anatol Kontush
- National Institute for Health and Medical Research (INSERM), UMR-ICAN 1166, Paris, France,
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39
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Rouet P, Harmancey R, Turkieh A, Caubère C, Barutaut M, Koukoui F, Dambrin C, Galinier M, Smih F. [A matter of fat: APOO regulates mitochondrial function in the heart]. Med Sci (Paris) 2015; 31:31-4. [PMID: 25658728 DOI: 10.1051/medsci/20153101010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Philippe Rouet
- Inserm U1048, équipe 7, obésité et insuffisance cardiaque : approches moléculaires et cliniques, BP 84225, 1, avenue Jean Poulhès, 31432 Toulouse Cedex 4, France
| | - Romain Harmancey
- Inserm U1048, équipe 7, obésité et insuffisance cardiaque : approches moléculaires et cliniques, BP 84225, 1, avenue Jean Poulhès, 31432 Toulouse Cedex 4, France
| | - Annie Turkieh
- Inserm U1048, équipe 7, obésité et insuffisance cardiaque : approches moléculaires et cliniques, BP 84225, 1, avenue Jean Poulhès, 31432 Toulouse Cedex 4, France
| | - Céline Caubère
- Inserm U1048, équipe 7, obésité et insuffisance cardiaque : approches moléculaires et cliniques, BP 84225, 1, avenue Jean Poulhès, 31432 Toulouse Cedex 4, France
| | - Manon Barutaut
- Inserm U1048, équipe 7, obésité et insuffisance cardiaque : approches moléculaires et cliniques, BP 84225, 1, avenue Jean Poulhès, 31432 Toulouse Cedex 4, France
| | - François Koukoui
- Inserm U1048, équipe 7, obésité et insuffisance cardiaque : approches moléculaires et cliniques, BP 84225, 1, avenue Jean Poulhès, 31432 Toulouse Cedex 4, France
| | - Camille Dambrin
- Inserm U1048, équipe 7, obésité et insuffisance cardiaque : approches moléculaires et cliniques, BP 84225, 1, avenue Jean Poulhès, 31432 Toulouse Cedex 4, France
| | - Michel Galinier
- Inserm U1048, équipe 7, obésité et insuffisance cardiaque : approches moléculaires et cliniques, BP 84225, 1, avenue Jean Poulhès, 31432 Toulouse Cedex 4, France
| | - Fatima Smih
- Inserm U1048, équipe 7, obésité et insuffisance cardiaque : approches moléculaires et cliniques, BP 84225, 1, avenue Jean Poulhès, 31432 Toulouse Cedex 4, France
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40
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Wu CL, Zhao SP, Yu BL. Intracellular role of exchangeable apolipoproteins in energy homeostasis, obesity and non-alcoholic fatty liver disease. Biol Rev Camb Philos Soc 2014; 90:367-76. [PMID: 24834836 DOI: 10.1111/brv.12116] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 04/10/2014] [Accepted: 04/17/2014] [Indexed: 02/06/2023]
Affiliation(s)
- Chen-Lu Wu
- Department of Cardiology; The Second Xiangya Hospital, Central South University; Changsha Hunan 410011 China
| | - Shui-Ping Zhao
- Department of Cardiology; The Second Xiangya Hospital, Central South University; Changsha Hunan 410011 China
| | - Bi-Lian Yu
- Department of Cardiology; The Second Xiangya Hospital, Central South University; Changsha Hunan 410011 China
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41
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Turkieh A, Caubère C, Barutaut M, Desmoulin F, Harmancey R, Galinier M, Berry M, Dambrin C, Polidori C, Casteilla L, Koukoui F, Rouet P, Smih F. Apolipoprotein O is mitochondrial and promotes lipotoxicity in heart. J Clin Invest 2014; 124:2277-86. [PMID: 24743151 DOI: 10.1172/jci74668] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 02/20/2014] [Indexed: 12/16/2022] Open
Abstract
Diabetic cardiomyopathy is a secondary complication of diabetes with an unclear etiology. Based on a functional genomic evaluation of obesity-associated cardiac gene expression, we previously identified and cloned the gene encoding apolipoprotein O (APOO), which is overexpressed in hearts from diabetic patients. Here, we generated APOO-Tg mice, transgenic mouse lines that expresses physiological levels of human APOO in heart tissue. APOO-Tg mice fed a high-fat diet exhibited depressed ventricular function with reduced fractional shortening and ejection fraction, and myocardial sections from APOO-Tg mice revealed mitochondrial degenerative changes. In vivo fluorescent labeling and subcellular fractionation revealed that APOO localizes with mitochondria. Furthermore, APOO enhanced mitochondrial uncoupling and respiration, both of which were reduced by deletion of the N-terminus and by targeted knockdown of APOO. Consequently, fatty acid metabolism and ROS production were enhanced, leading to increased AMPK phosphorylation and Ppara and Pgc1a expression. Finally, we demonstrated that the APOO-induced cascade of events generates a mitochondrial metabolic sink whereby accumulation of lipotoxic byproducts leads to lipoapoptosis, loss of cardiac cells, and cardiomyopathy, mimicking the diabetic heart-associated metabolic phenotypes. Our data suggest that APOO represents a link between impaired mitochondrial function and cardiomyopathy onset, and targeting APOO-dependent metabolic remodeling has potential as a strategy to adjust heart metabolism and protect the myocardium from impaired contractility.
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42
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Beyond the Standard Lipid Profile: What is Known about Apolipoproteins, Lp(a), and Lipoprotein Particle Distributions in Children. CURRENT CARDIOVASCULAR RISK REPORTS 2014. [DOI: 10.1007/s12170-014-0381-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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43
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Wu CL, Zhao SP, Yu BL. Microarray analysis provides new insights into the function of apolipoprotein O in HepG2 cell line. Lipids Health Dis 2013; 12:186. [PMID: 24341743 PMCID: PMC3878747 DOI: 10.1186/1476-511x-12-186] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 12/13/2013] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Apolipoprotein O (apoO) is a new member of the apolipoprotein family. However, data on its physiological functions are limited and inconsistent. Using a microarray expression analysis, this study explored the function of apoO in liver cells. METHODS HepG2 cells were treated either with oleic acid or tumor necrosis factor-α for 24 h. mRNA and protein expression of apoO were assessed by quantitative real-time PCR (qRT-PCR) and Western blot respectively. An efficient lentiviral siRNA vector targeting the human apoO gene was designed and constructed. The gene expression profile of HepG2 human hepatocellular carcinoma cells transfected with the apoO silencing vector was investigated using a whole-genome oligonucleotide microarray. The expression levels of some altered genes were validated using qRT-PCR. RESULTS ApoO expression in HepG2 cells was dramatically affected by lipid and inflammatory stimuli. A total of 282 differentially expressed genes in apoO-silenced HepG2 cells were identified by microarray analysis. These genes included those participating in fatty acid metabolism, such as ACSL4, RGS16, CROT and CYP4F11, and genes participating in the inflammatory response, such as NFKBIZ, TNFSF15, USP2, IL-17, CCL23, NOTCH2, APH-1B and N2N. The gene Uncoupling protein 2 (UCP2), which is involved in both these metabolic pathways, demonstrated significant changes in mRNA level after transfection. CONCLUSIONS It is likely that apoO participates in fatty acid metabolism and the inflammatory response in HepG2 cells, and UCP2 may act as a mediator between lipid metabolism and inflammation in apoO-silenced HepG2 cells.
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Affiliation(s)
- Chen-Lu Wu
- Department of Cardiology, the Second Xiangya Hospital of Central South University, Middle Ren-Min Road No.139, Changsha, Hunan, 410011, PR China
| | - Shui-Ping Zhao
- Department of Cardiology, the Second Xiangya Hospital of Central South University, Middle Ren-Min Road No.139, Changsha, Hunan, 410011, PR China
| | - Bi-Lian Yu
- Department of Cardiology, the Second Xiangya Hospital of Central South University, Middle Ren-Min Road No.139, Changsha, Hunan, 410011, PR China
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APOOL is a cardiolipin-binding constituent of the Mitofilin/MINOS protein complex determining cristae morphology in mammalian mitochondria. PLoS One 2013; 8:e63683. [PMID: 23704930 PMCID: PMC3660581 DOI: 10.1371/journal.pone.0063683] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 04/05/2013] [Indexed: 11/23/2022] Open
Abstract
Mitochondrial cristae morphology is highly variable and altered under numerous pathological conditions. The protein complexes involved are largely unknown or only insufficiently characterized. Using complexome profiling we identified apolipoprotein O (APOO) and apolipoprotein O-like protein (APOOL) as putative components of the Mitofilin/MINOS protein complex which was recently implicated in determining cristae morphology. We show that APOOL is a mitochondrial membrane protein facing the intermembrane space. It specifically binds to cardiolipin in vitro but not to the precursor lipid phosphatidylglycerol. Overexpression of APOOL led to fragmentation of mitochondria, a reduced basal oxygen consumption rate, and altered cristae morphology. Downregulation of APOOL impaired mitochondrial respiration and caused major alterations in cristae morphology. We further show that APOOL physically interacts with several subunits of the MINOS complex, namely Mitofilin, MINOS1, and SAMM50. We conclude that APOOL is a cardiolipin-binding component of the Mitofilin/MINOS protein complex determining cristae morphology in mammalian mitochondria. Our findings further assign an intracellular role to a member of the apolipoprotein family in mammals.
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45
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Lim HY, Thiam CH, Yeo KP, Bisoendial R, Hii CS, McGrath KCY, Tan KW, Heather A, Alexander JSJ, Angeli V. Lymphatic vessels are essential for the removal of cholesterol from peripheral tissues by SR-BI-mediated transport of HDL. Cell Metab 2013; 17:671-84. [PMID: 23663736 DOI: 10.1016/j.cmet.2013.04.002] [Citation(s) in RCA: 215] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 11/06/2012] [Accepted: 04/01/2013] [Indexed: 01/05/2023]
Abstract
Removal of cholesterol from peripheral tissues to the bloodstream via reverse cholesterol transport (RCT) is a process of major biological importance. Here we demonstrate that lymphatic drainage is required for RCT. We have previously shown that hypercholesterolemia in mice is associated with impaired lymphatic drainage and increased lipid accumulation in peripheral tissues. We now show that restoration of lymphatic drainage in these mice significantly improves cholesterol clearance. Conversely, obstruction of lymphatic vessels in wild-type mice significantly impairs RCT. Finally, we demonstrate using silencing RNA interference, neutralizing antibody, and transgenic mice that removal of cholesterol by lymphatic vessels is dependent on the uptake and transcytosis of HDL by scavenger receptor class B type I expressed on lymphatic endothelium. Collectively, this study challenges the current view that lymphatic endothelium is a passive exchange barrier for cholesterol transport and provides further evidence for its interplay with lipid biology in health and disease.
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Affiliation(s)
- Hwee Ying Lim
- Department of Microbiology, Immunology Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Republic of Singapore
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46
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Correlation of proteome-wide changes with social immunity behaviors provides insight into resistance to the parasitic mite, Varroa destructor, in the honey bee (Apis mellifera). Genome Biol 2012; 13:R81. [PMID: 23021491 PMCID: PMC3491398 DOI: 10.1186/gb-2012-13-9-r81] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 06/29/2012] [Accepted: 09/28/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Disease is a major factor driving the evolution of many organisms. In honey bees, selection for social behavioral responses is the primary adaptive process facilitating disease resistance. One such process, hygienic behavior, enables bees to resist multiple diseases, including the damaging parasitic mite Varroa destructor. The genetic elements and biochemical factors that drive the expression of these adaptations are currently unknown. Proteomics provides a tool to identify proteins that control behavioral processes, and these proteins can be used as biomarkers to aid identification of disease tolerant colonies. RESULTS We sampled a large cohort of commercial queen lineages, recording overall mite infestation, hygiene, and the specific hygienic response to V. destructor. We performed proteome-wide correlation analyses in larval integument and adult antennae, identifying several proteins highly predictive of behavior and reduced hive infestation. In the larva, response to wounding was identified as a key adaptive process leading to reduced infestation, and chitin biosynthesis and immune responses appear to represent important disease resistant adaptations. The speed of hygienic behavior may be underpinned by changes in the antenna proteome, and chemosensory and neurological processes could also provide specificity for detection of V. destructor in antennae. CONCLUSIONS Our results provide, for the first time, some insight into how complex behavioural adaptations manifest in the proteome of honey bees. The most important biochemical correlations provide clues as to the underlying molecular mechanisms of social and innate immunity of honey bees. Such changes are indicative of potential divergence in processes controlling the hive-worker maturation.
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47
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Yu BL, Wu CL, Zhao SP. Plasma apolipoprotein O level increased in the patients with acute coronary syndrome. J Lipid Res 2012; 53:1952-7. [PMID: 22693255 PMCID: PMC3413234 DOI: 10.1194/jlr.p023028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Apolipoprotein (apo) O is a novel apolipoprotein that is present predominantly in
high density lipoprotein (HDL). However, overexpression of apoO does not impact on
plasma HDL levels or functionality in human apoA-I transgenic mice. Thus, the
physiological function of apoO is not yet known. In the present study, we
investigated relationships between plasma apoO levels and high-sensitive C-reactive
protein (hs-CRP) levels, as well as other lipid parameters in healthy subjects (n
= 111) and patients with established acute coronary syndrome (ACS) (n =
50). ApoO was measured by the sandwich dot-blot technique with recombinant apoO as a
protein standard. Mean apoO level in healthy subjects was 2.21 ± 0.83
µg/ml whereas it was 4.94 ± 1.59 µg/ml in ACS patients. There were
significant differences in plasma level of apoO between two groups
(P < 0.001). In univariate analysis, apoO correlated
significantly with lg(hsCRP) (r = 0.48, P
< 0.001) in ACS patients. Notably, no significant correlation between apoO and
other lipid parameters was observed. Logistic regression analysis showed that plasma
apoO level was an independent predictor of ACS (OR = 5.61, 95% CI
2.16–14.60, P < 0.001). In conclusion, apoO increased in
ACS patients, and may be regarded as an independent inflammatory predictor of ACS
patients.
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Affiliation(s)
- Bi-lian Yu
- Department of Cardiology, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China
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Sharma V, Ryan RO, Forte TM. Apolipoprotein A-V dependent modulation of plasma triacylglycerol: a puzzlement. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:795-9. [PMID: 22209939 DOI: 10.1016/j.bbalip.2011.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 12/12/2011] [Accepted: 12/13/2011] [Indexed: 02/07/2023]
Abstract
The discovery of apolipoprotein A-V (apoA-V) in 2001 has raised a number of intriguing questions about its role in lipid transport and triglyceride (TG) homeostasis. Genome wide association studies (GWAS) have consistently identified APOA5 as a contributor to plasma TG levels. Single nucleotide polymorphisms (SNP) within the APOA5 gene locus have been shown to correlate with elevated plasma TG. Furthermore, transgenic and knockout mouse models support the view that apoA-V plays a critical role in maintenance of plasma TG levels. The present review describes recent concepts pertaining to apoA-V SNP analysis and their association with elevated plasma TG. The interaction of apoA-V with glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1) is discussed relative to its postulated role in TG-rich lipoprotein catabolism. The potential role of intracellular apoA-V in regulation of TG homeostasis, as a function of its ability to associate with cytosolic lipid droplets, is reviewed. While some answers are emerging, numerous mysteries remain with regard to this low abundance, yet potent, modulator of TG homeostasis. Given the strong correlation between elevated plasma TG and heart disease, there is great scientific and public interest in deciphering the numerous biological riddles presented by apoA-V. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
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Affiliation(s)
- Vineeta Sharma
- Center for Prevention of Obesity, Diabetes, and Cardiovascular Disease, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
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Hoppins S, Collins SR, Cassidy-Stone A, Hummel E, Devay RM, Lackner LL, Westermann B, Schuldiner M, Weissman JS, Nunnari J. A mitochondrial-focused genetic interaction map reveals a scaffold-like complex required for inner membrane organization in mitochondria. ACTA ACUST UNITED AC 2011; 195:323-40. [PMID: 21987634 PMCID: PMC3198156 DOI: 10.1083/jcb.201107053] [Citation(s) in RCA: 346] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Statement MITO-MAP, a high-density genetic interaction map in budding yeast, identifies a mitochondrial inner membrane–associated complex that promotes normal mitochondrial membrane organization and morphology. To broadly explore mitochondrial structure and function as well as the communication of mitochondria with other cellular pathways, we constructed a quantitative, high-density genetic interaction map (the MITO-MAP) in Saccharomyces cerevisiae. The MITO-MAP provides a comprehensive view of mitochondrial function including insights into the activity of uncharacterized mitochondrial proteins and the functional connection between mitochondria and the ER. The MITO-MAP also reveals a large inner membrane–associated complex, which we term MitOS for mitochondrial organizing structure, comprised of Fcj1/Mitofilin, a conserved inner membrane protein, and five additional components. MitOS physically and functionally interacts with both outer and inner membrane components and localizes to extended structures that wrap around the inner membrane. We show that MitOS acts in concert with ATP synthase dimers to organize the inner membrane and promote normal mitochondrial morphology. We propose that MitOS acts as a conserved mitochondrial skeletal structure that differentiates regions of the inner membrane to establish the normal internal architecture of mitochondria.
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Affiliation(s)
- Suzanne Hoppins
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
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Zhang H, Wang Y, Li J, Yu J, Pu J, Li L, Zhang H, Zhang S, Peng G, Yang F, Liu P. Proteome of skeletal muscle lipid droplet reveals association with mitochondria and apolipoprotein a-I. J Proteome Res 2011; 10:4757-68. [PMID: 21870882 DOI: 10.1021/pr200553c] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The lipid droplet (LD) is a universal organelle governing the storage and turnover of neutral lipids. Mounting evidence indicates that elevated intramuscular triglyceride (IMTG) in skeletal muscle LDs is closely associated with insulin resistance and Type 2 Diabetes Mellitus (T2DM). Therefore, the identification of the skeletal muscle LD proteome will provide some clues to dissect the mechanism connecting IMTG with T2DM. In the present work, we identified 324 LD-associated proteins in mouse skeletal muscle LDs through mass spectrometry analysis. Besides lipid metabolism and membrane traffic proteins, a remarkable number of mitochondrial proteins were observed in the skeletal muscle LD proteome. Furthermore, imaging by fluorescence microscopy and transmission electronic microscopy (TEM) directly demonstrated that mitochondria closely adhere to LDs in vivo. Moreover, our results revealed for the first time that apolipoprotein A-I (apo A-I), the principal apolipoprotein of high density lipoprotein (HDL) particles, was also localized on skeletal muscle LDs. Further studies verified that apo A-I was expressed endogenously by skeletal muscle cells. In conclusion, we report the protein composition and characterization of skeletal muscle LDs and describe a novel LD-associated protein, apo A-I.
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Affiliation(s)
- Huina Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
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