Biomarkers of Glycosaminoglycans (GAG) accumulation in patients with mucopolysaccharidosis type VI-LeukoGAG, Corneal Opacification (COM) and Carotid Intima Media Thickening (CIMT).

Mucopolysaccharidosis type VI (MPS VI) is an autosomal recessive lysosomal storage disorder characterized by deficient activity of arylsulfatase B enzyme (ASB) resulting in cellular accumulation of dermatan sulfate (DS) and chondroitin sulfate (CS) that leads to cell injury. Urinary glycosaminoglycans (GAG) are often used as a biomarker in MPS diseases for diagnosis and to monitor treatment efficacy. This study evaluated leukocyte GAGs (leukoGAG) and skin GAGs as alternate biomarkers representing intracellular GAG changes in patients with MPS VI and treated with enzyme replacement therapy (ERT). In addition, we evaluated corneal opacification measurements (COM) and carotid intima media thickness (CIMT) as indicators of GAG accumulation and tissue injury. The study was performed in a serial two-step design in a single center. A quantitative method to measure leukoGAG levels in leukocytes was developed in Study 1 to compare the GAG levels between MPS VI patients and a control group and to assess correlations between leukoGAG and urineGAG. Study 2 validated the leukoGAG measurement, assessed the effect of ERT infusion on leukoGAG and ASB activity in leukocytes, identified correlations between leukoGAG and other biomarkers, and assessed differences in GAG accumulation between MPS VI patients and control subjects. In Study 1, leukoCS and leukoDS levels were significantly higher in the MPS VI group than the control group (leukoCS: 37.9 ± 10.2 and 2.9 ± 1.5 µg/µg protein, respectively, p = 0.005; leukoDS: 0.26 ± 0.2 and 0.0 ± 0.0 µg/µg protein, respectively, p = 0.028) with positive correlations between leukoCS and urine CS and leukoDS and urineDS. In Study 2, leukoCS (32.0 ± 11.8 vs 6.9 ± 3.1 µg/mg protein, p = 0.005) and leukoDS (0.4 ± 0.1 and 0.2 ± 0.1 µg/mg protein, p = 0.020) were significantly higher compared with control subjects. Thus, these results highlight the potential of leukoGAG as a new biomarker representing intracellular GAG accumulation in MPS VI patients and may be valuable for patient management.

Reduction of lysosome abundance and GAG accumulation after odiparcil treatment in MPS I and MPS VI models.

Deficiencies of lysosomal enzymes responsible for the degradation of glycosaminoglycans (GAG) cause pathologies commonly known as the mucopolysaccharidoses (MPS). Each type of MPS is caused by a deficiency in a specific GAG-degrading enzyme and is characterized by an accumulation of disease-specific GAG species. Previously, we have shown the potential of the beta-D-xyloside, odiparcil, as an oral GAG clearance therapy for Maroteaux-Lamy syndrome (MPS VI), an MPS characterized by an accumulation of chondroitin sulphate (CS) and dermatan sulphate (DS). This work suggested that odiparcil acts via diverting the synthesis of CS and DS into odiparcil-bound excretable GAG. Here, we investigated the effect of odiparcil on lysosomal abundance in fibroblasts from patients with MPS I and MPS VI. In MPS VI fibroblasts, odiparcil reduced the accumulation of a lysosomal-specific lysotracker dye. Interestingly, a reduction of the lysotracker dye was also observed in odiparcil-treated fibroblasts from patients with MPS I, a disorder characterized by an accumulation of DS and heparan sulphate (HS). Furthermore, odiparcil was shown to be effective in reducing CS, DS, and HS concentrations in liver and eye, as representative organs, in MPS VI and MPS I mice treated with 3 doses of odiparcil over 3 and 9 months, respectively. In conclusion, our data demonstrates odiparcil efficiently reduced lysosome abundance and tissue GAG concentrations in in vitro and in vivo models of MPS VI and MPS I and has potential as a treatment for these disorders.

MPS VI associated ocular phenotypes in an MPS VI murine model and the therapeutic effects of odiparcil treatment.

Maroteaux - Lamy syndrome (mucopolysaccharidosis type VI, MPS VI) is a lysosomal storage disease resulting from insufficient enzymatic activity for degradation of the specific glycosaminoglycans (GAG) chondroitin sulphate (CS) and dermatan sulphate (DS). Among the most pronounced MPS VI clinical manifestations caused by cellular accumulation of excess CS and DS are eye disorders, in particular those that affect the cornea. Ocular manifestations are not treated by the current standard of care, enzyme replacement therapy (ERT), leaving patients with a significant unmet need. Using in vitro and in vivo models, we previously demonstrated the potential of the ß-D-xyloside, odiparcil, as an oral GAG clearance therapy for MPS VI. Here, we characterized the eye phenotypes in MPS VI arylsulfatase B deficient mice (Arsb-) and studied the effects of odiparcil treatment in early and established disease models. Severe levels of opacification and GAG accumulation were detected in the eyes of MPS VI Arsb- mice. Histological examination of MPS VI Arsb- eyes showed an aggregate of corneal phenotypes, including reduction in the corneal epithelium thickness and number of epithelial cell layers, and morphological malformations in the stroma. In addition, colloidal iron staining showed specifically GAG accumulation in the cornea. Orally administered odiparcil markedly reduced GAG accumulation in the eyes of MPS VI Arsb- mice in both disease models and restored the corneal morphology (epithelial layers and stromal structure). In the early disease model of MPS VI, odiparcil partially reduced corneal opacity area, but did not affect opacity area in the established model. Analysis of GAG types accumulating in the MPS VI Arsb- eyes demonstrated major contribution of DS and CS, with some increase in heparan sulphate (HS) as well and all were reduced with odiparcil treatment. Taken together, we further reveal the potential of odiparcil to be an effective therapy for eye phenotypes associated with MPS VI disease.

Oral treatment for mucopolysaccharidosis VI: Outcomes of the first phase IIa study with odiparcil.

Mucopolysaccharidosis (MPS) disorders are a group of rare, progressive lysosomal storage diseases characterized by the accumulation of glycosaminoglycans (GAGs) and classified according to the deficient enzyme. Enzyme replacement therapy (ERT) of MPS VI has limited effects on ophthalmic, cardiovascular, and skeletal systems. Odiparcil is an orally available small molecule that results in the synthesis of odiparcil-linked GAGs facilitating their excretion and reducing cellular and tissue GAG accumulation. Improve MPS treatment was a Phase 2a study of the safety, pharmacokinetics/pharmacodynamics, and efficacy of two doses of odiparcil in patients with MPS VI. The core study was a 26-week, randomized, double-blind, placebo-controlled trial in patients receiving ERT and an open-label, noncomparative, single-dose cohort not receiving ERT. Patients aged ≥ 16 years receiving ERT were randomized to odiparcil 250 or 500 mg twice daily or placebo. Patients without ERT received odiparcil 500 mg twice daily. Of 20 patients enrolled, 13 (65.0%) completed the study. Odiparcil increased total urine GAGs (uGAGs), chondroitin sulfate, and dermatan sulfate concentrations. A linear increase in uGAG levels and odiparcil exposure occurred with increased odiparcil dose. Odiparcil demonstrated a good safety and tolerability profile. Individual analyses found more improvements in pain, corneal clouding, cardiac, vascular, and respiratory functions in the odiparcil groups vs placebo. This study confirmed the mechanism of action and established the safety of odiparcil with clinical beneficial effects after only a short treatment duration in an advanced stage of disease. Further assessment of odiparcil in younger patients is needed.

Odiparcil, a potential glycosaminoglycans clearance therapy in mucopolysaccharidosis VI-Evidence from in vitro and in vivo models.

Mucopolysaccharidoses are a class of lysosomal storage diseases, characterized by enzymatic deficiency in the degradation of specific glycosaminoglycans (GAG). Pathological accumulation of excess GAG leads to multiple clinical symptoms with systemic character, most severely affecting bones, muscles and connective tissues. Current therapies include periodic intravenous infusion of supplementary recombinant enzyme (Enzyme Replacement Therapy-ERT) or bone marrow transplantation. However, ERT has limited efficacy due to poor penetration in some organs and tissues. Here, we investigated the potential of the ß-D-xyloside derivative odiparcil as an oral GAG clearance therapy for Maroteaux-Lamy syndrome (Mucopolysaccharidosis type VI, MPS VI). In vitro, in bovine aortic endothelial cells, odiparcil stimulated the secretion of sulphated GAG into culture media, mainly of chondroitin sulphate (CS) /dermatan sulphate (DS) type. Efficacy of odiparcil in reducing intracellular GAG content was investigated in skin fibroblasts from MPS VI patients where odiparcil was shown to reduce efficiently the accumulation of intracellular CS with an EC50 in the range of 1 µM. In vivo, in wild type rats, after oral administrations, odiparcil was well distributed, achieving µM concentrations in MPS VI disease-relevant tissues and organs (bone, cartilage, heart and cornea). In MPS VI Arylsulphatase B deficient mice (Arsb-), after chronic oral administration, odiparcil consistently stimulated the urinary excretion of sulphated GAG throughout the treatment period and significantly reduced tissue GAG accumulation in liver and kidney. Furthermore, odiparcil diminished the pathological cartilage thickening observed in trachea and femoral growth plates of MPS VI mice. The therapeutic efficacy of odiparcil was similar in models of early (treatment starting in juvenile, 4 weeks old mice) or established disease (treatment starting in adult, 3 months old mice). Our data demonstrate that odiparcil effectively diverts the synthesis of cellular glycosaminoglycans into secreted soluble species and this effect can be used for reducing cellular and tissue GAG accumulation in MPS VI models. Therefore, our data reveal the potential of odiparcil as an oral GAG clearance therapy for MPS VI patients.

Peroxisome proliferator-activated receptor delta (PPARdelta) activation protects H9c2 cardiomyoblasts from oxidative stress-induced apoptosis.

OBJECTIVE: Activation of peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma plays beneficial roles in cardiovascular disorders such as atherosclerosis and heart reperfusion. Although PPARalpha and gamma have been documented to reduce oxidative stress in the vasculature and the heart, the role of PPARdelta remains poorly studied. METHODS AND RESULTS: We focused on PPARdelta function in the regulation of oxidative stress-induced apoptosis in the rat cardiomyoblast cell line H9c2. Using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we showed that PPARdelta is the predominantly expressed isotype whereas PPARalpha was weakly detected. By performing cell viability assays, we also showed that the selective PPARdelta agonist GW501516 protected cells from H(2)O(2)-induced cell death. The protective effect of GW501516 was due to an inhibition of H(2)O(2)-triggered apoptosis as shown by annexin-V labeling, DNA fragmentation analysis, and caspase-3 activity measurement. We demonstrated by transient transfection of a dominant negative mutant of PPARdelta that the protection induced by GW501516 was totally dependent on PPARdelta. Semi-quantitative RT-PCR and Western blotting analysis demonstrated that GW501516 treatment upregulated catalase. Moreover, forced overexpression of catalase inhibited H(2)O(2)-triggered apoptosis, as evidenced by annexin-V labeling. CONCLUSION: Taken together, our results account for an important role of PPARdelta in inhibiting the onset of oxidative stress-induced apoptosis in H9c2 cells. PPARdelta appears to be a new therapeutic target for the regulation of heart reperfusion-associated oxidative stress and stimulation of enzymatic antioxidative defences.

Neuron restrictive silencer factor NRSF/REST is a transcriptional repressor of neuropilin-1 and diminishes the ability of semaphorin 3A to inhibit keratinocyte migration.

Neuropilin-1 (NRP1) is expressed by endothelial cells and neurons and serves as a receptor for both vascular endothelial growth factor (VEGF), an angiogenesis factor, and semaphorin 3A (Sema3A), a mediator of axonal guidance. We show here that NRP1 is also expressed in keratinocytes in vitro and in vivo. However, nothing has been reported about the regulation or function of keratinocyte NRP1. Using NRP1 promoter constructs in HaCaT cells, a keratinocyte cell line, we could demonstrate that a neuron restrictive silencer element (NRSE) was implicated in transcriptional repression of the NRP1 gene. Electrophoretic mobility shift assays demonstrated that the neuron restrictive silencer factor (NRSF) binds to NRSE. Overexpression of NRSF in HaCaT cells decreased NRP1 RNA and protein, whereas a dominant negative NRSF increased NRP1. Furthermore, the histone deacetylase inhibitor trichostatin A, an inhibitor of NRSF silencing activity, also increased NRP1 levels. NRP2 expression was not affected. Epidermal growth factor (EGF) and heparin-binding EGF-like growth factor (HB-EGF) strongly up-regulated NRP1 expression, concomitant with down-regulation of NRSF. Other keratinocyte mitogens such as keratinocyte growth factor (KGF) had no effect. To address function, HaCaT cells were exposed to two NRP1 ligands, VEGF165 and Sema3A. Neither had an effect on proliferation, whereas Sema3A, but not VEGF165, inhibited cell migration. Down-regulation of NRP1 by NRSF overexpression reduced Sema3A activity. It was concluded that NRSF is a transcription factor that silences NRP1 expression and thereby diminishes the Sema3A mediated inhibition of HaCaT keratinocyte migration.