Elevated Cystine Levels in Cultured Skin Fibroblasts From Patients With I-Cell Disease

A characteristic of the human lysosomal disorder I-cell disease is an abnormal excretion of most lysosomal hydrolases, including beta-N-acetyl-D-glucosaminidase (EC 3.2.1.30; beta-hexosaminidase) by cultured skin fibroblasts. Treatment of I-cell cultures with cycloheximide or tunicamycin demonstrated that (1) I-cell fibroblasts rapidly excrete all newly synthesized beta-hexosaminidase, (2) two qualitatively distinct pools of beta-hexosaminidase isoenzymes exist inside I-cell fibroblasts, one of which is a rapid-turnover excretory pool, and (3) the induction of an abnormal glycosylation of beta-hexosaminidase by tunicamycin in normal or I-cell fibroblast cultures does not affect subsequent excretion of the enzyme.

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CULTURED SKIN FIBROBLASTS IN DISORDERS OF GLYCOPROTEIN CATABOLISM AND I-CELL DISEASE

Developmental Medicine & Child Neurology ◽

10.1111/j.1469-8749.1974.tb03353.x ◽

2008 ◽

Vol 16 (3) ◽

pp. 376-378 ◽

Cited By ~ 3

Author(s):

S. Autio ◽

P. Aula ◽

V. Näntö

Keyword(s):

Skin Fibroblasts ◽

Cell Disease ◽

Cultured Skin

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Electron Microscopy of Fibroblasts from Myotonic Muscular Dystrophy Patients

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098976 ◽

1981 ◽

Vol 39 ◽

pp. 498-499

Author(s):

S. E. Miller ◽

G. B. Hartwig ◽

R. A. Nielsen ◽

A. P. Frost ◽

A. D. Roses

Keyword(s):

Electron Microscopy ◽

Muscular Dystrophy ◽

Genetic Diseases ◽

Skin Fibroblasts ◽

Inborn Errors ◽

Cytoplasmic Inclusions ◽

Cultured Skin ◽

Myotonic Muscular Dystrophy ◽

Glycosaminoglycan Metabolism

Many genetic diseases can be demonstrated in skin cells cultured in vitro from patients with inborn errors of metabolism. Since myotonic muscular dystrophy (MMD) affects many organs other than muscle, it seems likely that this defect also might be expressed in fibroblasts. Detection of an alteration in cultured skin fibroblasts from patients would provide a valuable tool in the study of the disease as it would present a readily accessible and controllable system for examination. Furthermore, fibroblast expression would allow diagnosis of fetal and presumptomatic cases. An unusual staining pattern of MMD cultured skin fibroblasts as seen by light microscopy, namely, an increase in alcianophilia and metachromasia, has been reported; both these techniques suggest an altered glycosaminoglycan metabolism An altered growth pattern has also been described. One reference on cultured skin fibroblasts from a different dystrophy (Duchenne Muscular Dystrophy) reports increased cytoplasmic inclusions seen by electron microscopy. Also, ultrastructural alterations have been reported in muscle and thalamus biopsies from MMD patients, but no electron microscopical data is available on MMD cultured skin fibroblasts.

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