globotriaosylceramide has been researched along with migalastat* in 16 studies
3 review(s) available for globotriaosylceramide and migalastat
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Chaperone Therapy in Fabry Disease.
Fabry disease is an X-linked lysosomal multisystem storage disorder induced by a mutation in the alpha-galactosidase A (GLA) gene. Reduced activity or deficiency of alpha-galactosidase A (AGAL) leads to escalating storage of intracellular globotriaosylceramide (GL-3) in numerous organs, including the kidneys, heart and nerve system. The established treatment for 20 years is intravenous enzyme replacement therapy. Lately, oral chaperone therapy was introduced and is a therapeutic alternative in patients with amenable mutations. Early starting of therapy is essential for long-term improvement. This review describes chaperone therapy in Fabry disease. Topics: 1-Deoxynojirimycin; alpha-Galactosidase; Fabry Disease; Humans; Male; Mutation; Time-to-Treatment; Trihexosylceramides | 2022 |
Migalastat: A Review in Fabry Disease.
Fabry disease is a rare lysosomal disorder characterized by deficient or absent α-galactosidase A activity resulting from mutations in the GLA gene. Migalastat (Galafold™), a pharmacological chaperone, stabilizes and facilitates trafficking of amenable mutant forms of α-galactosidase A enzyme from the endoplasmic reticulum to lysosomes and increases its lysosomal activity. Oral migalastat is the first pharmacological chaperone approved for treating patients [aged ≥ 18 years (USA and Canada) or ≥ 16 years in other countries] with Fabry disease who have a migalastat-amenable GLA mutation. In the FACETS trial in enzyme replacement therapy (ERT)-naive patients with GLA mutations amenable or non-amenable to migalastat, there was no significant difference between the migalastat and placebo groups for the proportion of patients achieving a ≥ 50% reduction in the number of globotriaosylceramide (GL-3) inclusions/kidney interstitial capillary (KIC) at 6 months [primary endpoint; intent-to-treat (ITT) population]. In the modified ITT population (i.e. patients with migalastat-amenable GLA mutations), relative to placebo, migalastat treatment significantly reduced the mean number of GL-3 inclusions/KIC and plasma lyso-globotriaosylsphingosine levels at 6 months. Among evaluable patients, migalastat maintained renal function and reduced cardiac mass after ≤ 24 months' therapy. In the ATTRACT trial in ERT-experienced patients, renal function was maintained during 18 months of migalastat or ERT; however, migalastat significantly reduced cardiac mass compared with ERT. Migalastat was generally well tolerated in both of these trials. Given its convenient oral regimen and the limited therapeutic options available, migalastat is an important treatment option for Fabry disease in patients with migalastat-amenable GLA mutations. Topics: 1-Deoxynojirimycin; Adolescent; Adult; Aged; Aged, 80 and over; Dose-Response Relationship, Drug; Drug Approval; Enzyme Replacement Therapy; Fabry Disease; Female; Glycolipids; Humans; Male; Middle Aged; Mutation; Sphingolipids; Trihexosylceramides | 2019 |
Fabry Nephropathy: An Evidence-Based Narrative Review.
Fabry disease (FD) is a rare, X-linked disorder caused by mutations in the GLA gene encoding the enzyme α-galactosidase A. Complete or partial deficiency in this enzyme leads to intracellular accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids in many cell types throughout the body, including the kidney. Progressive accumulation of Gb3 in podocytes, endothelial cells, epithelial cells, and tubular cells contribute to the renal symptoms of FD, which manifest as proteinuria and reduced glomerular filtration rate leading to renal insufficiency. A correct diagnosis of FD, although challenging, has considerable implications regarding treatment, management, and counseling. The diagnosis may be confirmed by demonstrating the enzyme deficiency in males and by identifying the specific GLA gene mutation in male and female patients. Treatment with enzyme replacement therapy, as part of the therapeutic strategy to prevent complications of the disease, may be beneficial in stabilizing renal function or slowing its decline, particularly in the early stages of the disease. Emergent treatments for FD include the recently approved chaperone molecule migalastat for patients with amenable mutations. The objective of this report is to provide an updated overview on Fabry nephropathy, with a focus on the most relevant aspects of its epidemiology, diagnosis, pathophysiology, and treatment options. Topics: 1-Deoxynojirimycin; Enzyme Replacement Therapy; Fabry Disease; Female; Galactosidases; Humans; Kidney Diseases; Male; Trihexosylceramides | 2018 |
2 trial(s) available for globotriaosylceramide and migalastat
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Migalastat improves diarrhea in patients with Fabry disease: clinical-biomarker correlations from the phase 3 FACETS trial.
Fabry disease is frequently characterized by gastrointestinal symptoms, including diarrhea. Migalastat is an orally-administered small molecule approved to treat the symptoms of Fabry disease in patients with amenable mutations.. We evaluated minimal clinically important differences (MCID) in diarrhea based on the corresponding domain of the patient-reported Gastrointestinal Symptom Rating Scale (GSRS) in patients with Fabry disease and amenable mutations (N = 50) treated with migalastat 150 mg every other day or placebo during the phase 3 FACETS trial (NCT00925301).. After 6 months, significantly more patients receiving migalastat versus placebo experienced improvement in diarrhea based on a MCID of 0.33 (43% vs 11%; p = .02), including the subset with baseline diarrhea (71% vs 20%; p = .02). A decline in kidney peritubular capillary globotriaosylceramide inclusions correlated with diarrhea improvement; patients with a reduction > 0.1 were 5.6 times more likely to have an improvement in diarrhea than those without (p = .031).. Migalastat was associated with a clinically meaningful improvement in diarrhea in patients with Fabry disease and amenable mutations. Reductions in kidney globotriaosylceramide may be a useful surrogate endpoint to predict clinical benefit with migalastat in patients with Fabry disease.. NCT00925301 ; June 19, 2009. Topics: 1-Deoxynojirimycin; Adolescent; Adult; Aged; Biomarkers; Diarrhea; Fabry Disease; Female; Humans; Kidney; Male; Middle Aged; Mutation; Trihexosylceramides; Young Adult | 2018 |
Treatment of Fabry's Disease with the Pharmacologic Chaperone Migalastat.
Fabry's disease, an X-linked disorder of lysosomal α-galactosidase deficiency, leads to substrate accumulation in multiple organs. Migalastat, an oral pharmacologic chaperone, stabilizes specific mutant forms of α-galactosidase, increasing enzyme trafficking to lysosomes.. The initial assay of mutant α-galactosidase forms that we used to categorize 67 patients with Fabry's disease for randomization to 6 months of double-blind migalastat or placebo (stage 1), followed by open-label migalastat from 6 to 12 months (stage 2) plus an additional year, had certain limitations. Before unblinding, a new, validated assay showed that 50 of the 67 participants had mutant α-galactosidase forms suitable for targeting by migalastat. The primary end point was the percentage of patients who had a response (≥50% reduction in the number of globotriaosylceramide inclusions per kidney interstitial capillary) at 6 months. We assessed safety along with disease substrates and renal, cardiovascular, and patient-reported outcomes.. The primary end-point analysis, involving patients with mutant α-galactosidase forms that were suitable or not suitable for migalastat therapy, did not show a significant treatment effect: 13 of 32 patients (41%) who received migalastat and 9 of 32 patients (28%) who received placebo had a response at 6 months (P=0.30). Among patients with suitable mutant α-galactosidase who received migalastat for up to 24 months, the annualized changes from baseline in the estimated glomerular filtration rate (GFR) and measured GFR were -0.30±0.66 and -1.51±1.33 ml per minute per 1.73 m(2) of body-surface area, respectively. The left-ventricular-mass index decreased significantly from baseline (-7.7 g per square meter; 95% confidence interval [CI], -15.4 to -0.01), particularly when left ventricular hypertrophy was present (-18.6 g per square meter; 95% CI, -38.2 to 1.0). The severity of diarrhea, reflux, and indigestion decreased.. Among all randomly assigned patients (with mutant α-galactosidase forms that were suitable or not suitable for migalastat therapy), the percentage of patients who had a response at 6 months did not differ significantly between the migalastat group and the placebo group. (Funded by Amicus Therapeutics; ClinicalTrials.gov numbers, NCT00925301 [study AT1001-011] and NCT01458119 [study AT1001-041].). Topics: 1-Deoxynojirimycin; Adolescent; Adult; Aged; alpha-Galactosidase; Diarrhea; Double-Blind Method; Fabry Disease; Female; Glomerular Filtration Rate; Heart Ventricles; Humans; Hypertrophy, Left Ventricular; Kidney; Male; Middle Aged; Mutation; Trihexosylceramides; Ultrasonography; Young Adult | 2016 |
11 other study(ies) available for globotriaosylceramide and migalastat
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Mutation-specific Fabry disease patient-derived cell model to evaluate the amenability to chaperone therapy.
Patients with Fabry disease (FD) and amenable mutations can be treated with the chaperone migalastat to restore endogenous α-galactosidase A (AGAL) activity. However, certain amenable mutations do not respond biochemically in vivo as expected. Here, we aimed to establish a patient-specific and mutation-specific cell model to evaluate the amenability to chaperone therapy in FD.. Since current tests to determine amenability are limited to heterologous mutation expression in HEK293T cells with endogenous AGAL activity, we generated CRISPR/Cas9-mediated AGAL-deficient HEK293T cells as a basis for mutant overexpression. Furthermore, primary urinary cells from patients were isolated and immortalised as a patient-specific cell model system to evaluate the amenability to chaperone therapy.. Under treatment (>13 months), carriers of p.N215S (n=6) showed a significant reduction of plasma lyso-Gb3 (p<0.05). Lyso-Gb3 levels in carriers of p.L294S increased (p<0.05) and two patients developed severe albuminuria. Both missense mutations were amenable in wild-type HEK293T cells (p<0.05), but presented different responses in CRISPR/Cas9-mediated AGAL knockouts and immortalised urinary cells. Chaperone incubation resulted in increased AGAL activity (p<0.0001) and intracellular globotriaosylceramide (Gb3) reduction (p<0.05) in immortalised p.N215S cells but not in p.L294S and IVS2+1 G>A cells.. We conclude that repeated AGAL activity measurements in patients' white blood cells are mandatory to assess the in vivo amenability to migalastat. Plasma lyso-Gb3 might be an appropriate tool to measure the biochemical response to migalastat. Patients with low AGAL activities and increasing lyso-Gb3 levels despite in vitro amenability might not benefit sufficiently from chaperone treatment. Topics: 1-Deoxynojirimycin; alpha-Galactosidase; Cell- and Tissue-Based Therapy; Enzyme Replacement Therapy; Fabry Disease; Gene Editing; HEK293 Cells; Humans; Molecular Chaperones; Precision Medicine; Trihexosylceramides | 2019 |
[The Fabry nephropathy: new insight in diagnosis, monitoring and treatment].
Fabry disease is a rare inborn error of the enzyme α-galactosidase (Α-Gal) and results in lysosomal substrate accumulation in tissues with a wide range of clinical presentations. The disease has attracted a lot of interest over the last years and several issues has been discovered up to now leading to increasing knowledge and awareness of the disease. However, several aspects are still unclear and under investigation. Thus, the new challenges that physicians encounter are the discovering of the pathogenic mechanisms, the neutralising antibodies to ERT, the long-term efficacy of therapies. In this article, we summarise and review the latest developments in the science community regarding diagnosis, management and monitoring of Fabry disease concerning in particular its physiopathology, novel biomarkers, antibodies development and novel treatment options. Topics: 1-Deoxynojirimycin; alpha-Galactosidase; Disease Progression; Enzyme Replacement Therapy; Fabry Disease; Female; Glomerulosclerosis, Focal Segmental; Glycolipids; Heterozygote; Humans; Isoenzymes; Kidney Diseases; Male; Oxidative Stress; Podocytes; Recombinant Proteins; Sex Factors; Sphingolipids; Trihexosylceramides | 2019 |
Glucosylceramide synthase inhibition with lucerastat lowers globotriaosylceramide and lysosome staining in cultured fibroblasts from Fabry patients with different mutation types.
Fabry disease is an X-linked lysosomal storage disorder caused by mutations in the GLA gene coding for α-galactosidase A (α-GalA). The deleterious mutations lead to accumulation of α-GalA substrates, including globotriaosylceramide (Gb3) and globotriaosylsphingosine. Progressive glycolipid storage results in cellular dysfunction, leading to organ damage and clinical disease, i.e. neuropathic pain, impaired renal function and cardiomyopathy. Many Fabry patients are treated by bi-weekly intravenous infusions of replacement enzyme. While the only available oral therapy is an α-GalA chaperone, which is indicated for a limited number of patients with specific 'amenable' mutations. Lucerastat is an orally bioavailable inhibitor of glucosylceramide synthase (GCS) that is in late stage clinical development for Fabry disease. Here we investigated the ability of lucerastat to lower Gb3, globotriaosylsphingosine and lysosomal staining in cultured fibroblasts from 15 different Fabry patients. Patients' cells included 13 different pathogenic variants, with 13 cell lines harboring GLA mutations associated with the classic disease phenotype. Lucerastat dose dependently reduced Gb3 in all cell lines. For 13 cell lines the Gb3 data could be fit to an IC50 curve, giving a median IC50 [interquartile range (IQR)] = 11 μM (8.2-18); the median percent reduction (IQR) in Gb3 was 77% (70-83). Lucerastat treatment also dose dependently reduced LysoTracker Red staining of acidic compartments. Lucerastat's effects in the cell lines were compared to those with current treatments-agalsidase alfa and migalastat. Consequently, the GCS inhibitor lucerastat provides a viable mechanism to reduce Gb3 accumulation and lysosome volume, suitable for all Fabry patients regardless of genotype. Topics: 1-Deoxynojirimycin; alpha-Galactosidase; Cell Line; Fabry Disease; Female; Fibroblasts; Genotype; Glucosyltransferases; Humans; Kidney; Lysosomes; Male; Mutation; Trihexosylceramides | 2018 |
Reduction of podocyte globotriaosylceramide content in adult male patients with Fabry disease with amenable
Deficiency of α-galactosidase A (αGal-A) in Fabry disease leads to the accumulation mainly of globotriaosylceramide (GL3) in multiple renal cell types. Glomerular podocytes are relatively resistant to clearance of GL3 inclusions by enzyme replacement therapy (ERT). Migalastat, an orally bioavailable small molecule capable of chaperoning misfolded αGal-A to lysosomes, is approved in the European Union for the long-term treatment of patients with Fabry disease and amenable. We compared paired renal biopsies of eight adult men with amenable Fabry disease mutations at baseline and after 6 months of treatment with 150 mg migalastat every other day using quantitative unbiased electron microscopic morphometric methods.. Migalastat treatment led to a reduction in mean total GL3 inclusion volume per podocyte in renal biopsies from baseline to 6 months. This reduction correlated precisely with reduced mean podocyte volume. There was also a direct relationship between reduction in podocyte foot process width and the reduction in mean total podocyte GL3 content following 6 months of migalastat treatment, suggestive of reduced podocyte injury.. Migalastat treatment of 6 months duration in eight male patients with Fabry disease demonstrated effective GL3 clearance from the podocyte, an important and relatively ERT-resistant glomerular cell. Topics: 1-Deoxynojirimycin; Adult; alpha-Galactosidase; Enzyme Inhibitors; Fabry Disease; Humans; Male; Middle Aged; Podocytes; Treatment Outcome; Trihexosylceramides | 2017 |
Molecular basis of 1-deoxygalactonojirimycin arylthiourea binding to human α-galactosidase a: pharmacological chaperoning efficacy on Fabry disease mutants.
Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations in the GLA gene often leading to missense α-galactosidase A (α-Gal A) variants that undergo premature endoplasmic reticulum-associated degradation due to folding defects. We have synthesized and characterized a new family of neutral amphiphilic pharmacological chaperones, namely 1-deoxygalactonojirimycin-arylthioureas (DGJ-ArTs), capable of stabilizing α-Gal A and restoring trafficking. Binding to the enzyme is reinforced by a strong hydrogen bond involving the aryl-N'H thiourea proton and the catalytic aspartic acid acid D231 of α-Gal A, as confirmed by a 2.55 Å resolution cocrystal structure. Selected candidates enhanced α-Gal A activity and ameliorate globotriaosylceramide (Gb3) accumulation and autophagy impairments in FD cell cultures. Moreover, they acted synergistically with the proteostasis regulator 4-phenylbutyric acid, appearing to be promising leads as pharmacological chaperones for FD. Topics: 1-Deoxynojirimycin; alpha-Galactosidase; Animals; Autophagy; Chlorocebus aethiops; COS Cells; Crystallography, X-Ray; Enzyme Stability; Fabry Disease; Fibroblasts; Humans; Molecular Docking Simulation; Mutation; Protein Transport; Thiourea; Trihexosylceramides | 2014 |
Migalastat HCl reduces globotriaosylsphingosine (lyso-Gb3) in Fabry transgenic mice and in the plasma of Fabry patients.
Fabry disease (FD) results from mutations in the gene (GLA) that encodes the lysosomal enzyme α-galactosidase A (α-Gal A), and involves pathological accumulation of globotriaosylceramide (GL-3) and globotriaosylsphingosine (lyso-Gb3). Migalastat hydrochloride (GR181413A) is a pharmacological chaperone that selectively binds, stabilizes, and increases cellular levels of α-Gal A. Oral administration of migalastat HCl reduces tissue GL-3 in Fabry transgenic mice, and in urine and kidneys of some FD patients. A liquid chromatography-tandem mass spectrometry method was developed to measure lyso-Gb3 in mouse tissues and human plasma. Oral administration of migalastat HCl to transgenic mice reduced elevated lyso-Gb3 levels up to 64%, 59%, and 81% in kidney, heart, and skin, respectively, generally equal to or greater than observed for GL-3. Furthermore, baseline plasma lyso-Gb3 levels were markedly elevated in six male FD patients enrolled in Phase 2 studies. Oral administration of migalastat HCl (150 mg QOD) reduced urine GL-3 and plasma lyso-Gb3 in three subjects (range: 15% to 46% within 48 weeks of treatment). In contrast, three showed no reductions in either substrate. These results suggest that measurement of tissue and/or plasma lyso-Gb3 is feasible and may be warranted in future studies of migalastat HCl or other new potential therapies for FD. Topics: 1-Deoxynojirimycin; Administration, Oral; alpha-Galactosidase; Animals; Fabry Disease; Glycolipids; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mutation; Reproducibility of Results; Sphingolipids; Sphingosine; Trihexosylceramides | 2013 |
Synergy between the pharmacological chaperone 1-deoxygalactonojirimycin and the human recombinant alpha-galactosidase A in cultured fibroblasts from patients with Fabry disease.
Fabry disease (FD) is an X-linked inherited disease due to alpha-galactosidase A (alpha-Gal A) deficiency and characterized by lysosomal storage of globotriaosylceramide (Gb3) and related neutral glycosphingolipids. Storage of these substrates results in multisystem manifestations, including renal failure, cardiomyopathy, premature myocardial infarctions, stroke, chronic neuronopathic pain, gastrointestinal disturbances, and skin angiokeratoma. Enzyme replacement therapy (ERT) with recombinant human alpha-galactosidase A (rh-alpha-Gal A) is now available for the treatment of FD and in most patients results in clinical improvement or stabilization. However, ERT efficacy may vary in different tissues and its long-term effects remain to be defined. As a strategy to improve the efficacy of ERT, we tested the combination of rh-alpha-Gal A with the chaperone molecule 1-deoxynojirimycin (DGJ) in cultured FD fibroblasts with negligible residual enzyme activity. Compared to the effects of rh-alpha-Gal A alone, co-administration of DGJ and rh-alpha-Gal A resulted in better correction (4.8 to 16.9-fold) of intracellular alpha-Gal A activity, and increased amounts of the enzyme within the lysosomal compartment. The clearance of lyso-Gb3, one of the substrates stored in FD and a potent inhibitor of alpha-Gal A, was also significantly improved with the co-administration of DGJ and rh-alpha-Gal A. This study provides additional evidence for a synergistic effect between ERT and pharmacological chaperone therapy and supports the idea that the efficacy of combination protocols may be superior to ERT alone. Topics: 1-Deoxynojirimycin; alpha-Galactosidase; Case-Control Studies; Exons; Fabry Disease; Fibroblasts; Genotype; Humans; Lysosomes; Male; Microscopy, Confocal; Microscopy, Fluorescence; Mutation; Recombinant Proteins; Trihexosylceramides | 2012 |
Increased globotriaosylceramide levels in a transgenic mouse expressing human alpha1,4-galactosyltransferase and a mouse model for treating Fabry disease.
Fabry disease is a lysosomal storage disorder caused by an α-galactosidase A (α-Gal A) deficiency and resulting in the accumulation of glycosphingolipids, predominantly globotriaosylceramide (Gb3). A transgenic mouse expressing the human α-Gal A R301Q mutant in an α-Gal A-knockout background (TgM/KO) should be useful for studying active-site-specific chaperone (ASSC) therapy for Fabry disease. However, the Gb3 content in the heart tissue of this mouse was too low to detect an ASSC-induced effect. To increase the Gb3 levels in mouse organs, we created transgenic mice (TgG3S) expressing human α1,4-galactosyltransferase (Gb3 synthase). High levels of Gb3 were observed in all major organs of the TgG3S mouse. A TgG3S (+/-)M(+/-)/KO mouse was prepared by cross-breeding the TgG3S and TgM/KO mice and the Gb3 content in the heart of the TgG3S(+/-)M(+/-)/KO mouse was 1.4 µg/mg protein, higher than in the TgM(+/-)/KO (<0.1 µg/mg protein). Treatment with an ASSC, 1-deoxygalactonojirimycin, caused a marked induction of α-Gal A activity and a concomitant reduction of the Gb3 content in the TgG3S(+/-) M(+/-)/KO mouse organs. These data indicated that the TgG3S(+/-) M(+/-)/KO mouse was suitable for studying ASSC therapy for Fabry disease, and that the TgG3S mouse would be useful for studying the effect of high Gb3 levels in mouse organs. Topics: 1-Deoxynojirimycin; alpha-Galactosidase; Animals; Crosses, Genetic; Disease Models, Animal; Enzyme Activation; Fabry Disease; Female; Galactosyltransferases; Humans; Kidney; Liver; Mice; Mice, Knockout; Mice, Transgenic; Molecular Chaperones; Spleen; Trihexosylceramides; Up-Regulation | 2011 |
The pharmacological chaperone 1-deoxygalactonojirimycin reduces tissue globotriaosylceramide levels in a mouse model of Fabry disease.
Fabry disease is an X-linked lysosomal storage disorder caused by a deficiency in alpha-galactosidase A (alpha-Gal A) activity and subsequent accumulation of the substrate globotriaosylceramide (GL-3), which contributes to disease pathology. The pharmacological chaperone (PC) DGJ (1-deoxygalactonojirimycin) binds and stabilizes alpha-Gal A, increasing enzyme levels in cultured cells and in vivo. The ability of DGJ to reduce GL-3 in vivo was investigated using transgenic (Tg) mice that express a mutant form of human alpha-Gal A (R301Q) on a knockout background (Tg/KO), which leads to GL-3 accumulation in disease-relevant tissues. Four-week daily oral administration of DGJ to Tg/KO mice resulted in significant and dose-dependent increases in alpha-Gal A activity, with concomitant GL-3 reduction in skin, heart, kidney, brain, and plasma; 24-week administration resulted in even greater reductions. Compared to daily administration, less frequent DGJ administration, including repeated cycles of 4 days with DGJ followed by 3 days without or every other day with DGJ, resulted in even greater GL-3 reductions that were comparable to those obtained with Fabrazyme. Collectively, these data indicate that oral administration of DGJ increases mutant alpha-Gal A activity and reduces GL-3 in disease-relevant tissues in Tg/KO mice, and thus merits further evaluation as a treatment for Fabry disease. Topics: 1-Deoxynojirimycin; alpha-Galactosidase; Animals; Blotting, Western; Disease Models, Animal; Fabry Disease; Humans; Immunohistochemistry; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Trihexosylceramides | 2010 |
The association of Shiga-like toxin with detergent-resistant membranes is modulated by glucosylceramide and is an essential requirement in the endoplasmic reticulum for a cytotoxic effect.
Receptor-mediated internalization to the endoplasmic reticulum (ER) and subsequent retro-translocation to the cytosol are essential sequential processes required for the productive intoxication of susceptible mammalian cells by Shiga-like toxin-1 (SLTx). Recently, it has been proposed that the observed association of certain ER-directed toxins and viruses with detergent-resistant membranes (DRM) may provide a general mechanism for their retrograde transport to endoplasmic reticulum (ER). Here, we show that DRM recruitment of SLTx bound to its globotriosylceramide (Gb(3)) receptor is mediated by the availability of other glycosphingolipids. Reduction in glucosylceramide (GlcCer) levels led to complete protection against SLTx and a reduced cell surface association of bound toxin with DRM. This reduction still allowed efficient binding and transport of the toxin to the ER. However, toxin sequestration within DRM of the ER was abolished under reduced GlcCer conditions, suggesting that an association of toxin with lipid microdomains or rafts in the ER (where these are defined by detergent insolubility) is essential for a later step leading to or involving retro-translocation of SLTx across the ER membrane. In support of this, we show that a number of ER residents, proteins intimately involved in the process of ER dislocation of misfolded proteins, are present in DRM. Topics: 1-Deoxynojirimycin; Animals; Cell Death; Cell Line, Tumor; Cell Membrane; Chlorocebus aethiops; Detergents; Endoplasmic Reticulum; Glucosylceramides; Glycosphingolipids; HeLa Cells; Humans; Intracellular Membranes; Proteasome Inhibitors; Protein Transport; Shiga Toxin 1; Trihexosylceramides; Vero Cells | 2006 |
A synthetic chaperone corrects the trafficking defect and disease phenotype in a protein misfolding disorder.
Mutations in proteins that induce misfolding and proteasomal degradation are common causes of inherited diseases. Fabry disease is a lysosomal storage disorder caused by a deficiency of alpha-galactosidase A activity in lysosomes resulting in an accumulation of glycosphingolipid globotriosylceramide (Gb3). Some classical Fabry hemizygotes and all cardiac variants have residual alpha-galactosidase A activity, but the mutant enzymes are unstable. Such mutant enzymes appear to be misfolded, recognized by the ER protein quality control, and degraded before sorting into lysosomes. Hence, correction of the trafficking defect of mutant but catalytically active enzyme into lysosomes would be beneficial for treatment of the disease. Here we show that a nontoxic competitive inhibitor (1-deoxygalactonojirimycin) of alpha-galactosidase A functions as a chemical chaperone by releasing ER-retained mutant enzyme from BiP. The treatment with subinhibitory doses resulted in efficient, long-term lysosomal trafficking of the ER-retained mutant alpha-galactosidase A. Successful clearance of lysosomal Gb3 storage and a near-normal lysosomal phenotype was achieved in human Fabry fibroblasts harboring different types of mutations. Small molecule chemical chaperones will be therapeutically useful for various lysosomal storage disorders as well as for other genetic metabolic disorders caused by mutant but nonetheless catalytically active enzymes. Topics: 1-Deoxynojirimycin; alpha-Galactosidase; Amino Acid Substitution; Animals; Arginine; Cells, Cultured; Fabry Disease; Fibroblasts; Glutamine; Humans; Lysosomes; Mice; Mice, Transgenic; Molecular Chaperones; Mutation; Phenotype; Protein Binding; Protein Folding; Protein Transport; Trihexosylceramides | 2005 |