muramidase and Gaucher-Disease

Lysosomal storage diseases (LSDs) are often caused by mutations compromising lysosomal enzyme folding in the endoplasmic reticulum (ER), leading to degradation and loss of function. Mass spectrometry analysis of Gaucher fibroblasts treated with mechanistically distinct molecules that increase LSD enzyme folding, trafficking, and function resulted in the identification of nine commonly downregulated and two jointly upregulated proteins, which we hypothesized would be critical proteostasis network components for ameliorating loss-of-function diseases. LIMP-2 and FK506 binding protein 10 (FKBP10) were validated as such herein. Increased FKBP10 levels accelerated mutant glucocerebrosidase degradation over folding and trafficking, whereas decreased ER FKBP10 concentration led to more LSD enzyme partitioning into the calnexin profolding pathway, enhancing folding and activity to levels thought to ameliorate LSDs. Thus, targeting FKBP10 appears to be a heretofore unrecognized therapeutic strategy to ameliorate LSDs.

Topics: alpha-Mannosidase; Amino Acid Sequence; Cell Line; Endoplasmic Reticulum; Fibroblasts; Gaucher Disease; Glucosylceramidase; Homeostasis; Humans; Lectins; Molecular Sequence Data; Muramidase; Neoplasm Proteins; Protein Folding; Protein Transport; Proteolysis; Proteomics; Reproducibility of Results; Tacrolimus Binding Proteins

Gaucher disease (GD; glucosylceramidosis) is caused by a deficient activity of the enzyme glucocerebrosidase (GC). Clinical manifestations are highly variable and cannot be predicted accurately on the basis of the properties of mutant GC. Analysis of secondary abnormalities, such as elevated plasma levels of some hydrolases, may help to increase insight into the complicated pathophysiology of the disease and could also provide useful disease markers. The recent availability of enzyme supplementation therapy for GD increases the need for markers as early predictors of the efficacy of treatment. We report the finding of a very marked increase in chitotrisidase activity in plasma of 30 of 32 symptomatic type 1 GD patients studied: the median activity being > 600 times the median value in plasma of healthy volunteers. In three GC-deficient individuals without clinical symptoms, only slight increases were noted. Chitotriosidase activity was absent in plasma of three control subjects and two patients. During enzyme supplementation therapy, chitotriosidase activity declined dramatically. We conclude that plasma chitotriosidase levels can serve as a new diagnostic hallmark of GD and should prove to be useful in assessing whether clinical manifestations of GD are present and for monitoring the efficacy of therapeutic intervention.

Topics: Adolescent; Adult; Aged; Alkaline Phosphatase; Child; Child, Preschool; Female; Gaucher Disease; Hexosaminidases; Humans; Male; Middle Aged; Muramidase; Trisaccharides

Serum angiotensin-converting enzyme in a patient with type 2 acute neuronopathic Gaucher's disease (242 nmol/min/ml) was 10.8 times higher than values for eight patients with other hereditary neurologic abnormalities (22.5 +/- 2.0) and 9.4 times higher than those for 12 patients with other diseases (25.7 +/- 2.6) (P less than 0.001). Serum lysozyme was not elevated in the patient with type 2 Gaucher's disease. These results indicate that elevated serum angiotensin-converting enzyme in an infant with neurologic involvement and hepatosplenomegaly is suggestive of the possibility of type 2 Gaucher's disease. Typical Gaucher's cells and fibrosis were observed by light and electron microscopy of the liver. An aspect hitherto unreported in Gaucher's disease or in the liver was that approximately 20% of the collagen fibrils were of the long-spacing type, with periodicity of 1,000 to 1,100 A and diameters of 900 to 1,500 A.

Topics: Acute Disease; Gaucher Disease; Humans; Infant; Liver; Male; Muramidase; Peptidyl-Dipeptidase A

Topics: Adult; Aged; Collagen; Female; Gaucher Disease; Humans; Liver; Liver Diseases; Male; Middle Aged; Muramidase; Peptidyl-Dipeptidase A

In adult chronic non-neuronopathic (Type 1) Gaucher's disease significant (p less than 0.001) elevations of angiotensin converting enzyme in serum (93.3 +/- 14.8 nmol/min/ml; number elevated, 8/11; normal control 32.2 +/- 1.30, n = 58) and spleen (5.62 +/- 0.35 nmol/min/mg protein, n = 2; control, 0.431 +/- 0.101, n = 4) and serum lysozyme (15.6 +/- 3.37 mug/ml; number elevated, 4/5) were observed. The KM for hippuryl-L-histidyl-L-leucine of Gaucher (1.31 mM) and normal (1.23 mM) serum angiotensin converting enzyme were similar. The increased angiotensin converting enzyme (ACE) in Gaucher's disease may be related to the genetic defect resulting in increased ACE synthesis in Gaucher cells, or perhaps generally, while high lysozyme may reflect an increased body mass of reticuloendothelial cells. These enzyme elevations may be of use in suggesting the possible presence of Gaucher's disease and perhaps in assessing the magnitude of pathologic involvement.

Topics: Adult; Aged; Chronic Disease; Diagnosis, Differential; Female; Gaucher Disease; Humans; Male; Middle Aged; Muramidase; Peptidyl-Dipeptidase A; Spleen