title: Pompe disease results in a Golgi-based glycosylation deficit in human induced pluripotent stem cell-derived cardiomyocytes.
abstract: Infantile-onset Pompe disease is an autosomal recessive disorder caused by the complete loss of lysosomal glycogen-hydrolyzing enzyme acid α-glucosidase (GAA) activity, which results in lysosomal glycogen accumulation and prominent cardiac and skeletal muscle pathology. The mechanism by which loss of GAA activity causes cardiomyopathy is poorly understood. We reprogrammed fibroblasts from patients with infantile-onset Pompe disease to generate induced pluripotent stem (iPS) cells that were differentiated to cardiomyocytes (iPSC-CM). Pompe iPSC-CMs had undetectable GAA activity and pathognomonic glycogen-filled lysosomes. Nonetheless, Pompe and control iPSC-CMs exhibited comparable contractile properties in engineered cardiac tissue. Impaired autophagy has been implicated in Pompe skeletal muscle; however, control and Pompe iPSC-CMs had comparable clearance rates of LC3-II-detected autophagosomes. Unexpectedly, the lysosome-associated membrane proteins, LAMP1 and LAMP2, from Pompe iPSC-CMs demonstrated higher electrophoretic mobility compared with control iPSC-CMs. Brefeldin A induced disruption of the Golgi in control iPSC-CMs reproduced the higher mobility forms of the LAMPs, suggesting that Pompe iPSC-CMs produce LAMPs lacking appropriate glycosylation. Isoelectric focusing studies revealed that LAMP2 has a more alkaline pI in Pompe compared with control iPSC-CMs due largely to hyposialylation. MALDI-TOF-MS analysis of N-linked glycans demonstrated reduced diversity of multiantennary structures and the major presence of a trimannose complex glycan precursor in Pompe iPSC-CMs. These data suggest that Pompe cardiomyopathy has a glycan processing abnormality and thus shares features with hypertrophic cardiomyopathies observed in the congenital disorders of glycosylation.
authors.affiliation: From the Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705, the WiCell Institute, Madison, Wisconsin 53719.
authors.forename: Kunil K
authors.initials: KK
authors.lastname: Raval
authors.affiliation: From the Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705.
authors.forename: Ran
authors.initials: R
authors.lastname: Tao
authors.affiliation: From the Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705.
authors.forename: Brent E
authors.initials: BE
authors.lastname: White
authors.affiliation: the Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792.
authors.forename: Willem J
authors.initials: WJ
authors.lastname: De Lange
authors.affiliation: From the Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705.
authors.forename: Chad H
authors.initials: CH
authors.lastname: Koonce
authors.affiliation: Cellular Dynamics International, Madison, Wisconsin 53711.
authors.forename: Junying
authors.initials: J
authors.lastname: Yu
authors.affiliation: the Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710.
authors.forename: Priya S
authors.initials: PS
authors.lastname: Kishnani
authors.affiliation: the Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706, the Genome Center of Wisconsin, University of Wisconsin, Madison, Wisconsin 53706, the Morgridge Institute for Research, Madison, Wisconsin 53715.
authors.forename: James A
authors.initials: JA
authors.lastname: Thomson
authors.affiliation: From the Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705, the Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin 53706, and.
authors.forename: Deane F
authors.initials: DF
authors.lastname: Mosher
authors.affiliation: the Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792.
authors.forename: John C
authors.initials: JC
authors.lastname: Ralphe
authors.affiliation: From the Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705, the Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706, the WiCell Institute, Madison, Wisconsin 53719, tjk@medicine.wisc.edu.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Kamp
mesh_terms: D015153:Blotting, Western; D002478:Cells, Cultured; D005838:Genotype; D006009:Glycogen Storage Disease Type II / Q000378:metabolism* / Q000473:pathology*; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D057026:Induced Pluripotent Stem Cells / Q000166:cytology*; D032383:Myocytes, Cardiac / Q000473:pathology*
keywords: Autophagy; Cardiomyopathy; Golgi; Induced Pluripotent Stem Cell (iPSC); Lysosomal Glycoprotein; N-linked Glycosylation; Pompe Disease; Tissue Engineering