Widespread Expression of a Membrane-Tethered Version of the Soluble Lysosomal Enzyme Palmitoyl Protein Thioesterase-1

Abstract Neuronal ceroid lipofuscinosis (NCL) type 1 (CLN1) is a neurodegenerative storage disorder caused by mutations in the gene encoding the lysosomal enzyme palmitoyl-protein thioesterase 1 (PPT1). CLN1 patients suffer from brain atrophy, mental and motor retardation, seizures, and retinal degeneration ultimately resulting in blindness. Here, we performed an in-depth analysis of the retinal phenotype of a PPT1-deficient mouse, an animal model of this condition. Reactive astrogliosis and microgliosis were evident in mutant retinas prior to the onset of retinal cell loss. Progressive accumulation of storage material, a pronounced dysregulation of various lysosomal proteins, and accumulation of sequestosome/p62-positive aggregates in the inner nuclear layer also preceded retinal degeneration. At advanced stages of the disease, the mutant retina was characterized by a significant loss of ganglion cells, rod and cone photoreceptor cells, and rod and cone bipolar cells. Results demonstrate that PPT1 dysfunction results in early-onset pathological alterations in the mutant retina, followed by a progressive degeneration of various retinal cell types at relatively late stages of the disease. Data will serve as a reference for future work aimed at developing therapeutic strategies for the treatment of retinal degeneration in CLN1 disease.

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Ultrastructure of Fibroblast Cultures, Lymphocytes, and Liver in Mucopolysaccharidoses Types I, II, III, IV, and VI.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068011 ◽

1970 ◽

Vol 28 ◽

pp. 204-205

Author(s):

George Hug ◽

William K. Schubert ◽

Shirley Soukup

Keyword(s):

Lysosomal Enzyme ◽

Apparent Lack ◽

Fibroblast Cultures ◽

Lysosomal Diseases ◽

Disease Specificity ◽

Deficient Activity

McKusick subdivided the syndrome of mucopolysaccharidoses into six types according to clinical, roentenographic, and genetic criteria and to the kind of mucopolysaccharide(s) excreted in the urine (1). Deficient activity of a lysosomal enzyme, (β-galactosidase, has recently been reported in types I, II and III of mucopolysaccharidoses as well as in generalized gangliosidosis (2). This apparent lack of disease specificity makes the enzymatic deficiency difficult to interpret. Nevertheless, the involvement of a lysosomal enzyme tends to characterize these disorders as lysosomal diseases.

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Electron Microscopy in the diagnosis of lysosomal storage diseases

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156316 ◽

1989 ◽

Vol 47 ◽

pp. 866-867

Author(s):

Carole Vogler ◽

Harvey S. Rosenberg

Keyword(s):

Electron Microscopy ◽

Lysosomal Enzyme ◽

Rectal Mucosa ◽

Lysosomal Storage Diseases ◽

Cell Types ◽

Lysosomal Storage ◽

Storage Material ◽

Ultrastructural Examination ◽

Blood Leukocytes ◽

Storage Diseases

Diagnostic procedures for evaluation of patients with lysosomal storage diseases (LSD) seek to identify a deficiency of a responsible lysosomal enzyme or accumulation of a substance that requires the missing enzyme for degradation. Most patients with LSD have progressive neurological degeneration and may have a variety of musculoskeletal and visceral abnormalities. In the LSD, the abnormally diminished lysosomal enzyme results in accumulation of unmetabolized catabolites in distended lysosomes. Because of the subcellular morphology and size of lysosomes, electron microscopy is an ideal tool to study tissue from patients with suspected LSD. In patients with LSD all cells lack the specific lysosomal enzyme but the distribution of storage material is dependent on the extent of catabolism of the substrate in each cell type under normal circumstances. Lysosmal storages diseases affect many cell types and tissues. Storage material though does not accumulate in all tissues and cell types and may be different biochemically and morphologically in different tissues.Conjunctiva, skin, rectal mucosa and peripheral blood leukocytes may show ultrastructural evidence of lysosomal storage even in the absence of clinical findings and thus any of these tissues can be used for ultrastructural examination in the diagnostic evaluation of patients with suspected LSD. Biopsy of skin and conjunctiva are easily obtained and provide multiple cell types including endothelium, epithelium, fibroblasts and nerves for ultrastructural study. Fibroblasts from skin and conjunctiva can also be utilized for the initiation of tissue cultures for chemical assays. Brain biopsy has been largely replaced by biopsy of more readily obtained tissue and by biochemical assays. Such assays though may give equivical or nondiagnostic results and in some lysosomal storage diseases an enzyme defect has not yet been identified and diagnoses can be made only by ultrastructural examination.

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