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Peifer-Weiß L, Kurban M, David C, Lubeck M, Kondadi AK, Nemer G, Reichert AS, Anand R. A X-linked nonsense APOO/MIC26 variant causes a lethal mitochondrial disease with progeria-like phenotypes. Clin Genet 2023; 104:659-668. [PMID: 37649161 DOI: 10.1111/cge.14420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/16/2023] [Accepted: 08/18/2023] [Indexed: 09/01/2023]
Abstract
APOO/MIC26 is a subunit of the MICOS complex required for mitochondrial cristae morphology and function. Here, we report a novel variant of the APOO/MIC26 gene that causes a severe mitochondrial disease with overall progeria-like phenotypes in two patients. Both patients developed partial agenesis of the corpus callosum, bilateral congenital cataract, hypothyroidism, and severe immune deficiencies. The patients died at an early age of 12 or 18 months. Exome sequencing revealed a mutation (NM_024122.5): c.532G>T (p.E178*) in the APOO/MIC26 gene that causes a nonsense mutation leading to the loss of 20 C-terminal amino acids. This mutation resulted in a highly unstable and degradation prone MIC26 protein, yet the remaining minute amounts of mutant MIC26 correctly localized to mitochondria and interacted physically with other MICOS subunits. MIC26 KO cells expressing MIC26 harboring the respective APOO/MIC26 mutation showed mitochondria with perturbed cristae architecture and fragmented morphology resembling MIC26 KO cells. We conclude that the novel mutation found in the APOO/MIC26 gene is a loss-of-function mutation impairing mitochondrial morphology and cristae morphogenesis.
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Affiliation(s)
- Leon Peifer-Weiß
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Mazen Kurban
- Department Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
- Department of Dermatology, American University of Beirut, Beirut, Lebanon
| | - Céline David
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Melissa Lubeck
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Arun Kumar Kondadi
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Georges Nemer
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Andreas S Reichert
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ruchika Anand
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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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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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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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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Navaratnarajah T, Anand R, Reichert AS, Distelmaier F. The relevance of mitochondrial morphology for human disease. Int J Biochem Cell Biol 2021; 134:105951. [PMID: 33610749 DOI: 10.1016/j.biocel.2021.105951] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/01/2021] [Accepted: 02/03/2021] [Indexed: 12/18/2022]
Abstract
Mitochondria are highly dynamic organelles, which undergo frequent structural and metabolic changes to fulfil cellular demands. To facilitate these processes several proteins are required to regulate mitochondrial shape and interorganellar communication. These proteins include the classical mitochondrial fusion (MFN1, MFN2, and OPA1) and fission proteins (DRP1, MFF, FIS1, etc.) as well as several other proteins that are directly or indirectly involved in these processes (e.g. YME1L, OMA1, INF2, GDAP1, MIC13, etc.). During the last two decades, inherited genetic defects in mitochondrial fusion and fission proteins have emerged as an important class of neurodegenerative human diseases with variable onset ranging from infancy to adulthood. So far, no causal treatment strategies are available for these disorders. In this review, we provide an overview about the current knowledge on mitochondrial dynamics under physiological conditions. Moreover, we describe human diseases, which are associated with genetic defects in these pathways.
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Affiliation(s)
- Tharsini Navaratnarajah
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Ruchika Anand
- Institute of Biochemistry and Molecular Biology I, Medical Faculty, Heinrich-Heine-University-Düsseldorf, Düsseldorf, Germany
| | - Andreas S Reichert
- Institute of Biochemistry and Molecular Biology I, Medical Faculty, Heinrich-Heine-University-Düsseldorf, Düsseldorf, Germany
| | - Felix Distelmaier
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
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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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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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9
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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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10
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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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11
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Aghababaeian A, Ghanbari Niaki A, Joshaghani H, Vakili MA, Hoseini S. Effects of Different Intensities of Circuit Resistance Training on Plasma level of High-Density Lipoprotein Subfractions and Apolipoprotein M in Untrained Young Men. MEDICAL LABORATORY JOURNAL 2019. [DOI: 10.29252/mlj.13.5.38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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12
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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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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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14
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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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15
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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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16
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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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17
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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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18
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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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19
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CRP Gene polymorphism contributes genetic susceptibility to dyslipidemia in Han Chinese population. Mol Biol Rep 2014; 41:2335-43. [DOI: 10.1007/s11033-014-3087-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 01/04/2014] [Indexed: 10/25/2022]
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20
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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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