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Cardiac myosin binding protein C regulates postnatal myocyte cytokinesis. Proc Natl Acad Sci U S A 2015; 112:9046-51. [PMID: 26153423 DOI: 10.1073/pnas.1511004112] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Homozygous cardiac myosin binding protein C-deficient (Mybpc(t/t)) mice develop dramatic cardiac dilation shortly after birth; heart size increases almost twofold. We have investigated the mechanism of cardiac enlargement in these hearts. Throughout embryogenesis myocytes undergo cell division while maintaining the capacity to pump blood by rapidly disassembling and reforming myofibrillar components of the sarcomere throughout cell cycle progression. Shortly after birth, myocyte cell division ceases. Cardiac MYBPC is a thick filament protein that regulates sarcomere organization and rigidity. We demonstrate that many Mybpc(t/t) myocytes undergo an additional round of cell division within 10 d postbirth compared with their wild-type counterparts, leading to increased numbers of mononuclear myocytes. Short-hairpin RNA knockdown of Mybpc3 mRNA in wild-type mice similarly extended the postnatal window of myocyte proliferation. However, adult Mybpc(t/t) myocytes are unable to fully regenerate the myocardium after injury. MYBPC has unexpected inhibitory functions during postnatal myocyte cytokinesis and cell cycle progression. We suggest that human patients with homozygous MYBPC3-null mutations develop dilated cardiomyopathy, coupled with myocyte hyperplasia (increased cell number), as observed in Mybpc(t/t) mice. Human patients, with heterozygous truncating MYBPC3 mutations, like mice with similar mutations, have hypertrophic cardiomyopathy. However, the mechanism leading to hypertrophic cardiomyopathy in heterozygous MYBPC3(+/-) individuals is myocyte hypertrophy (increased cell size), whereas the mechanism leading to cardiac dilation in homozygous Mybpc3(-/-) mice is primarily myocyte hyperplasia.
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Arai E, Gotoh M, Tian Y, Sakamoto H, Ono M, Matsuda A, Takahashi Y, Miyata S, Totsuka H, Chiku S, Komiyama M, Fujimoto H, Matsumoto K, Yamada T, Yoshida T, Kanai Y. Alterations of the spindle checkpoint pathway in clinicopathologically aggressive CpG island methylator phenotype clear cell renal cell carcinomas. Int J Cancer 2015; 137:2589-606. [PMID: 26061684 PMCID: PMC4755138 DOI: 10.1002/ijc.29630] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 04/15/2015] [Accepted: 05/20/2015] [Indexed: 01/08/2023]
Abstract
CpG-island methylator phenotype (CIMP)-positive clear cell renal cell carcinomas (RCCs) are characterized by accumulation of DNA hypermethylation of CpG islands, clinicopathological aggressiveness and poor patient outcome. The aim of this study was to clarify the molecular pathways participating in CIMP-positive renal carcinogenesis. Genome (whole-exome and copy number), transcriptome and proteome (two-dimensional image converted analysis of liquid chromatography-mass spectrometry) analyses were performed using tissue specimens of 87 CIMP-negative and 14 CIMP-positive clear cell RCCs and corresponding specimens of non-cancerous renal cortex. Genes encoding microtubule-associated proteins, such as DNAH2, DNAH5, DNAH10, RP1 and HAUS8, showed a 10% or higher incidence of genetic aberrations (non-synonymous single-nucleotide mutations and insertions/deletions) in CIMP-positive RCCs, whereas CIMP-negative RCCs lacked distinct genetic characteristics. MetaCore pathway analysis of CIMP-positive RCCs revealed that alterations of mRNA or protein expression were significantly accumulated in six pathways, all participating in the spindle checkpoint, including the "The metaphase checkpoint (p = 1.427 × 10(-6))," "Role of Anaphase Promoting Complex in cell cycle regulation (p = 7.444 × 10(-6))" and "Spindle assembly and chromosome separation (p = 9.260 × 10(-6))" pathways. Quantitative RT-PCR analysis revealed that mRNA expression levels for genes included in such pathways, i.e., AURKA, AURKB, BIRC5, BUB1, CDC20, NEK2 and SPC25, were significantly higher in CIMP-positive than in CIMP-negative RCCs. All CIMP-positive RCCs showed overexpression of Aurora kinases, AURKA and AURKB, and this overexpression was mainly attributable to increased copy number. These data suggest that abnormalities of the spindle checkpoint pathway participate in CIMP-positive renal carcinogenesis, and that AURKA and AURKB may be potential therapeutic targets in more aggressive CIMP-positive RCCs.
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Affiliation(s)
- Eri Arai
- Division of Molecular Pathology, National Cancer Center Research Institute, Tokyo, Japan
| | - Masahiro Gotoh
- Division of Molecular Pathology, National Cancer Center Research Institute, Tokyo, Japan
| | - Ying Tian
- Division of Molecular Pathology, National Cancer Center Research Institute, Tokyo, Japan
| | - Hiromi Sakamoto
- Division of Genetics, National Cancer Center Research Institute, Tokyo, Japan
| | - Masaya Ono
- Division of Chemotherapy and Clinical Research, National Cancer Center Research Institute, Tokyo, Japan
| | - Akio Matsuda
- Department of Allergy and Immunology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Yoriko Takahashi
- Bioscience Department, Business Development Division, Mitsui Knowledge Industry Co. Ltd, Tokyo, Japan
| | - Sayaka Miyata
- Bioscience Department, Business Development Division, Mitsui Knowledge Industry Co. Ltd, Tokyo, Japan
| | - Hirohiko Totsuka
- Bioinformatics Group, Research and Development Center, Solution Division 4, Hitachi Government and Public Corporation System Engineering Ltd, Tokyo, Japan
| | - Suenori Chiku
- Science Solutions Division, Mizuho Information and Research Institute, Inc, Tokyo, Japan
| | - Motokiyo Komiyama
- Department of Urology, National Cancer Center Hospital, Tokyo, Japan
| | - Hiroyuki Fujimoto
- Department of Urology, National Cancer Center Hospital, Tokyo, Japan
| | - Kenji Matsumoto
- Department of Allergy and Immunology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Tesshi Yamada
- Division of Chemotherapy and Clinical Research, National Cancer Center Research Institute, Tokyo, Japan
| | - Teruhiko Yoshida
- Division of Genetics, National Cancer Center Research Institute, Tokyo, Japan
| | - Yae Kanai
- Division of Molecular Pathology, National Cancer Center Research Institute, Tokyo, Japan
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