Pathologic gene expression in Gaucher disease: up-regulation of cysteine proteinases including osteoclastic cathepsin K

Abstract

Deficiency of lysosomal acid β-glucosidase induces glycolipid storage in the macrophages of Gaucher disease but the pathways of multisystem tissue injury and destruction are unknown. To investigate the cognate molecular pathology of this inflammatory disorder, genes that were differentially expressed in spleen samples from a patient with Gaucher disease (Gaucher spleen) were isolated. Of 64 complementary DNA (cDNA) fragments sequenced from an enriched Gaucher cDNA library, 5 encode lysosomal proteins (cathepsins B, K, and S, α-fucosidase, and acid lipase), 10 encode other known proteins, and 2 represent novel sequences from human macrophage cell lines. Transcript abundance of the cathepsins, novel genes, pulmonary and activation-regulated chemokine (PARC), and NMB, a putative tumor suppressor gene, was greatly increased. Immunoblotting showed increased mature forms of all 3 cathepsins found in samples of Gaucher spleens. Immunofluorescence microscopy showed strong cathepsin B and K reactions in sinusoidal endothelium and Gaucher cells. The respective means, plus or minus SD, of cathepsin B, K, and S activities were 183 ± 35, 97 ± 39, and 91 ± 45 nmol/min/mg protein in 4 Gaucher spleens, and 26 ± 4, 10.5 ± 2, and 4.0 ± 2.1 nmol/min/mg protein in 3 control spleens. Plasma cathepsin B, K, and S activities were also elevated in Gaucher disease plasma (P < .001), but compared with control plasma samples, neither cathepsin B nor K activities were significantly elevated in 8 patients with nonglycosphingolipid lysosomal storage diseases or in 9 patients with other glycosphingolipidoses, which suggests disease specificity. All 3 cathepsin activities were increased 2-fold to 3-fold in Gaucher sera compared with control sera. In all 6 patients treated by enzyme replacement for 16-22 months, serum cathepsin activities decreased significantly (P < .01). Longitudinal studies confirmed the progressive reduction of proteinase activities during imiglucerase therapy but in 3 Gaucher patients with mild disease not so treated, serum cathepsin activities remained constant or increased during follow-up. Enhanced expression of cysteine proteinases may promote tissue destruction. Moreover, the first identification of aberrant cathepsin K expression in hematopoietic tissue other than osteoclasts implicates this protease in the breakdown of the matrix that characterizes lytic bone lesions in Gaucher disease.

Modulation of bone turnover in orchidectomized rats treated with raloxifene and risedronate

“…Activity of cathepsin-K was measured as described by Moran et al [18]. Fifty microlitres of serum was diluted to 250 lL using 0.1% Brij-35 solution (Sigma -Aldrich chemie Gmbh) and preincubated with 250 lL incubation buffer [100 mM sodium acetate; pH 5.5, 5 mM EDTA, and 20 mM cysteine (Oxford Lab, Mumbai, India), as an activator] at 37°C for 5 min.…”

Plasma chitotriosidase and CCL18: Early biochemical surrogate markers in type B Niemann‐Pick disease

“…Very recently, another Gaucher cell marker, CCL18, has been identi¢ed by a proteomics-based survey of serum specimens of symptomatic Gaucher patients (Boot et al 2004). Increased expression of CCL18 mRNA had earlier been observed in an investigation on di¡erentially expressed genes in spleen of Gaucher patients (Moran et al 2000). The chemokine CCL18, which is massively released by Gaucher cells, is about 50-fold increased in plasma and can serve as a useful alternative surrogate marker for Gaucher cells in those patients who lack chitotriosidase for genetic reasons.…”

Biomarkers in the diagnosis of lysosomal storage disorders: proteins, lipids, and inhibodies

“…Abnormalities in levels of tartrate-resistant acid phosphatase (TRAP), angiotensin-converting enzyme (ACE), hexosaminidase, and lysozyme in serum samples from Gaucher patients had been documented for some time (Aerts and Hollak 1997). More recently, increased plasma levels of various cathepsins, including cathepsin K, were reported in patients with Gaucher disease (Moran et al 2000;). All of these proteins are known to be produced by macrophages; however, none of them appears to be a specific marker for the pathological Gaucher cells, and their levels in the serum of symptomatic patients with Gaucher disease may overlap with those observed in healthy individuals.…”