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Aksu-Menges E, Eylem CC, Nemutlu E, Gizer M, Korkusuz P, Topaloglu H, Talim B, Balci-Hayta B. Reduced mitochondrial fission and impaired energy metabolism in human primary skeletal muscle cells of Megaconial Congenital Muscular Dystrophy. Sci Rep 2021; 11:18161. [PMID: 34518586 PMCID: PMC8438035 DOI: 10.1038/s41598-021-97294-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 08/13/2021] [Indexed: 11/09/2022] Open
Abstract
Megaconial Congenital Muscular Dystrophy (CMD) is a rare autosomal recessive disorder characterized by enlarged mitochondria located mainly at the periphery of muscle fibers and caused by mutations in the Choline Kinase Beta (CHKB) gene. Although the pathogenesis of this disease is not well understood, there is accumulating evidence for the presence of mitochondrial dysfunction. In this study, we aimed to investigate whether imbalanced mitochondrial dynamics affects mitochondrial function and bioenergetic efficiency in skeletal muscle cells of Megaconial CMD. Immunofluorescence, confocal and transmission electron microscopy studies revealed impaired mitochondrial network, morphology, and localization in primary skeletal muscle cells of Megaconial CMD. The organelle disruption was specific only to skeletal muscle cells grown in culture. The expression levels of mitochondrial fission proteins (DRP1, MFF, FIS1) were found to be decreased significantly in both primary skeletal muscle cells and tissue sections of Megaconial CMD by Western blotting and/or immunofluorescence analysis. The metabolomic and fluxomic analysis, which were performed in Megaconial CMD for the first time, revealed decreased levels of phosphonucleotides, Krebs cycle intermediates, ATP, and altered energy metabolism pathways. Our results indicate that reduced mitochondrial fission and altered mitochondrial energy metabolism contribute to mitochondrial dysmorphology and dysfunction in the pathogenesis of Megaconial CMD.
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Affiliation(s)
- Evrim Aksu-Menges
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
| | - Cemil Can Eylem
- Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
| | - Emirhan Nemutlu
- Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
| | - Merve Gizer
- Department of Stem Cell Sciences, Graduate School of Health Sciences, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
| | - Petek Korkusuz
- Department of Histology and Embryology, Faculty of Medicine, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
| | - Haluk Topaloglu
- Department of Pediatrics, Division of Child Neurology, Faculty of Medicine, Hacettepe University, 06100, Sihhiye, Ankara, Turkey.,Department of Pediatrics, Yeditepe University, Istanbul, Turkey
| | - Beril Talim
- Department of Pediatrics, Pathology Unit, Faculty of Medicine, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
| | - Burcu Balci-Hayta
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, 06100, Sihhiye, Ankara, Turkey.
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Chan SH, Ho RS, Khong PL, Chung BH, Tsang MH, Yu MH, Yeung MC, Chan AO, Fung CW. Megaconial congenital muscular dystrophy: Same novel homozygous mutation in CHKB gene in two unrelated Chinese patients. Neuromuscul Disord 2019; 30:47-53. [PMID: 31926838 DOI: 10.1016/j.nmd.2019.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 10/26/2019] [Accepted: 10/28/2019] [Indexed: 10/25/2022]
Abstract
Megaconial congenital muscular dystrophy (CMD) is a rare form of congenital muscular dystrophy attributed to an autosomal recessive CHKB mutation. We report two unrelated Chinese girls with Megaconial CMD who harbored the same novel homozygous CHKB mutation but exhibited different phenotypes. Patient 1, who is now 8 years old, has autism, intellectual disabilities, mild girdle weakness, and characteristic muscle biopsy with COX-negative fibers. Patient 2, now 12 years old, has limited intelligence and marked weakness, with scoliosis, hip subluxation and early loss of ambulation. Both exhibited mildly elevated creatine kinase levels, have relative sparing of adductor longus and extensor digitorum longus on MRI leg muscles, and a c.598del (p.Gln200Argfs*11) homozygous CHKB loss-of-function mutation. Their parents are heterozygous carriers. This is the first report of Megaconial CMD in Chinese patients demonstrating the pathogenicity of the identified homozygous CHKB variant. A case review of all previously reported patients of different ethnicities is also included.
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Affiliation(s)
- Sophelia Hs Chan
- Department of Pediatrics and Adolescent Medicine, LKS Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong Special Administrative Region.
| | - Ronnie Sl Ho
- Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong Special Administrative Region
| | - P L Khong
- Department of Radiology, Queen Mary Hospital, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Brian Hy Chung
- Department of Pediatrics and Adolescent Medicine, LKS Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Mandy Hy Tsang
- Department of Pediatrics and Adolescent Medicine, LKS Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Mullin Hc Yu
- Department of Pediatrics and Adolescent Medicine, LKS Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Matthew Cw Yeung
- Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong Special Administrative Region
| | - Angel Ok Chan
- Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong Special Administrative Region
| | - C W Fung
- Department of Pediatrics and Adolescent Medicine, LKS Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong Special Administrative Region
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