title: Dysregulation of Mitochondrial Functions and Osteogenic Differentiation in Cisd2-Deficient Murine Induced Pluripotent Stem Cells.
abstract: Wolfram syndrome 2 (WFS2) is a premature aging syndrome caused by an irreversible mitochondria-mediated disorder. Cisd2, which regulates mitochondrial electron transport, has been recently identified as the causative gene of WFS2. The mouse Cisd2 knockout (KO) (Cisd2(-/-)) recapitulates most of the clinical manifestations of WFS2, including growth retardation, osteopenia, and lordokyphosis. However, the precise mechanisms underlying osteopenia in WFS2 and Cisd2 KO mice remain unknown. In this study, we collected embryonic fibroblasts from Cisd2-deficient embryos and reprogrammed them into induced pluripotent stem cells (iPSCs) via retroviral transduction with Oct4/Sox2/Klf4/c-Myc. Cisd2-deficient mouse iPSCs (miPSCs) exhibited structural abnormalities in their mitochondria and an impaired proliferative capability. The global gene expression profiles of Cisd2(+/+), Cisd2(+/-), and Cisd2(-/-) miPSCs revealed that Cisd2 functions as a regulator of both mitochondrial electron transport and Wnt/β-catenin signaling, which is critical for cell proliferation and osteogenic differentiation. Notably, Cisd2(-/-) miPSCs exhibited impaired Wnt/β-catenin signaling, with the downregulation of downstream genes, such as Tcf1, Fosl1, and Jun and the osteogenic regulator Runx2. Several differentiation markers for tridermal lineages were globally impaired in Cisd2(-/-) miPSCs. Alizarin red S staining and flow cytometry analysis further revealed that Cisd2(-/-) miPSCs failed to undergo osteogenic differentiation. Taken together, our results, as determined using an miPSC-based platform, have demonstrated that Cisd2 regulates mitochondrial function, proliferation, intracellular Ca(2+) homeostasis, and Wnt pathway signaling. Cisd2 deficiency impairs the activation of Wnt/β-catenin signaling and thereby contributes to the pathogeneses of osteopenia and lordokyphosis in WFS2 patients.
authors.affiliation: 1 Institute of Pharmacology, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Ping-Hsing
authors.initials: PH
authors.lastname: Tsai
authors.affiliation: 1 Institute of Pharmacology, National Yang-Ming University , Taipei, Taiwan .|2 Department of Medical Research, Taipei Veterans General Hospital , Taipei, Taiwan .
authors.forename: Yueh
authors.initials: Y
authors.lastname: Chien
authors.affiliation: 2 Department of Medical Research, Taipei Veterans General Hospital , Taipei, Taiwan .|3 Institute of Clinical Medicine, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Jen-Hua
authors.initials: JH
authors.lastname: Chuang
authors.affiliation: 1 Institute of Pharmacology, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Shih-Jie
authors.initials: SJ
authors.lastname: Chou
authors.affiliation: 2 Department of Medical Research, Taipei Veterans General Hospital , Taipei, Taiwan .|3 Institute of Clinical Medicine, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Chian-Hsu
authors.initials: CH
authors.lastname: Chien
authors.affiliation: 4 Institute of Anatomy & Cell Biology, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Ying-Hsiu
authors.initials: YH
authors.lastname: Lai
authors.affiliation: 4 Institute of Anatomy & Cell Biology, National Yang-Ming University , Taipei, Taiwan .|5 School of Medicine, National Yang-Ming University , Taipei, Taiwan .|6 Department of Obstetrics and Gynecology, Neurological Institute , Taipei Veterans General Hospital, Taipei, Taiwan .
authors.forename: Hsin-Yang
authors.initials: HY
authors.lastname: Li
authors.affiliation: 2 Department of Medical Research, Taipei Veterans General Hospital , Taipei, Taiwan .|5 School of Medicine, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Ko
authors.affiliation: 1 Institute of Pharmacology, National Yang-Ming University , Taipei, Taiwan .|7 Department of Pharmacy, Neurological Institute , Taipei Veterans General Hospital, Taipei, Taiwan .
authors.forename: Yuh-Lih
authors.initials: YL
authors.lastname: Chang
authors.affiliation: 5 School of Medicine, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Chen-Ying
authors.initials: CY
authors.lastname: Wang
authors.affiliation: 2 Department of Medical Research, Taipei Veterans General Hospital , Taipei, Taiwan .|3 Institute of Clinical Medicine, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Yung-Yang
authors.initials: YY
authors.lastname: Liu
authors.affiliation: 1 Institute of Pharmacology, National Yang-Ming University , Taipei, Taiwan .|5 School of Medicine, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Hsin-Chen
authors.initials: HC
authors.lastname: Lee
authors.affiliation: 8 Department of Ophthalmology, National Taiwan University Hospital , Taipei, Taiwan .
authors.forename: Chang-Hao
authors.initials: CH
authors.lastname: Yang
authors.affiliation: 9 Department of Life Sciences & Institute of Genome Sciences, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Ting-Fen
authors.initials: TF
authors.lastname: Tsai
authors.affiliation: 3 Institute of Clinical Medicine, National Yang-Ming University , Taipei, Taiwan .|10 Department of Neurosurgery, Neurological Institute , Taipei Veterans General Hospital, Taipei, Taiwan .
authors.forename: Yi-Yen
authors.initials: YY
authors.lastname: Lee
authors.affiliation: 1 Institute of Pharmacology, National Yang-Ming University , Taipei, Taiwan .|2 Department of Medical Research, Taipei Veterans General Hospital , Taipei, Taiwan .|3 Institute of Clinical Medicine, National Yang-Ming University , Taipei, Taiwan .|4 Institute of Anatomy & Cell Biology, National Yang-Ming University , Taipei, Taiwan .
authors.forename: Shih-Hwa
authors.initials: SH
authors.lastname: Chiou
mesh_terms: D000818:Animals; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D049109:Cell Proliferation / Q000235:genetics / Q000502:physiology; D006706:Homeostasis / Q000502:physiology; D057026:Induced Pluripotent Stem Cells / Q000166:cytology*; D000090062:Kruppel-Like Factor 4; D008822:Mice, Transgenic; D008928:Mitochondria / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000172:deficiency / Q000378:metabolism*; D010012:Osteogenesis / Q000235:genetics / Q000502:physiology*; D060449:Wnt Signaling Pathway / Q000502:physiology*
chemical_list: D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D009419:Nerve Tissue Proteins; C515811:Noxp70 protein, mouse