- Email: [email protected]
3. Computer-assisted teaching of mucopolysaccharidosis by patient management problems
Molecular Genetics and Metabolism 96 (2009) S12–S47
Contents lists available at ScienceDirect
Molecular Genetics and Metabolism journal homepage: www.elsevier.com/locate/ymgme
Abstracts for the Lysosomal Disease Network’s WORLD Symposium 1. New developments in biomarkers for lysosomal storage disorders Johannes Aerts, Academic Medical Center, Amsterdam, Netherlands
of this unique sheep model may help elucidate the dynamics of the LMC under normal and abnormal circumstances. doi:10.1016/j.ymgme.2008.11.003
A biomarker is generally an analyte that signals the extent of a biological process (e.g., storage cell formation in the case of lysosomal storage disorders), This is itself linked to clinical manifestations and outcome of a disease. A biomarker is preferably detectable in bodily fluids such as plasma or urine. Use of a biomarker may help to improve diagnose and to monitor disease progression and/or correction on therapeutic intervention. The ideal biomarker may assist in clinical management by guiding decision making regarding initiation of therapy and optimal individualized treatment regimens. This presentation discusses biomarker discovery and application using Gaucher disease as illustration. The first potent Gaucher biomarker was the enzyme chitotriosidase that is secreted by pathological lipid-laden macrophages (Gaucher cells) into the circulation. Subsequently, it is was discovered that CCL18/PARC is also secreted by Gaucher cells and offers an excellent alternative to assess the body burden on Gaucher cells. Recently, elevation of the chemokines MIP-1alpha and 1beta was discovered. These proteins are not produced by Gaucher cells but surrounding inflammatory macrophages. Label-free quantitative proteomics, LCMSE, allows detection of clear abnormalities in complement and coagulation cascades in symptomatic Gaucher patients, being responsive to therapy. Next to proteins, primary and secondary lipid abnormalities have also potential value as markers. Besides increased glucosylceramide, plasma of Gaucher patients contains increased ganglioside GM3. In the case of Fabry disease, a dramatic elevation in a metabolite, globotriaosylsphingosine of the primary storage lipid globotriosylceramide was recently discovered. This metabolite may play a role in vascular remodelling in patients and thus constitute a risk factor for pathogenesis. Recent data on the predictive value of plasma globotriaosylsphingosine will be presented in conclusion, biomarkers play an increasing role in guidance of clinical management and may also improve our understanding of pathophysiological events. doi:10.1016/j.ymgme.2008.11.002
2. Analysis of beta-galactosidase in an ovine model of GM1-gangliosidosis
3. Computer-assisted teaching of mucopolysaccharidosis by patient management problems Fatma Al-Jasmi, Laura Moldovan, Joe Clarke, Hospital for Sick Children, Toronto, On, Canada Background: Computer-assisted teaching holds significant promise for meeting the current demands and challenges of medical education by providing comprehensive, consistent and quality teaching materials from any location and at any time. Computer-assisted patient management problems (PMP) are well-known educational device and it has been used extensively in teaching in other areas. However; it has never been applied systematically to the teaching of inborn error of metabolism. Aim: To develop interactive teaching software for independent learning about the management of mucopolysaccharidoses, targeted to be used as a self-training by the general physicians. Method and result: The software consists of two main parts: the e-book and the clinic. The e-book contains six sections: overview, biochemistry, genetics, clinical manifestations, diagnosis and management. The e-book is visual illustrative with basic and clinical knowledge that is delivered to the trainee in simple and attractive way. All references are hyperlinked to PubMed and websites, for those needing further information or clarification. Through the contained hyperlinks the trainee has the opportunity to build further on the knowledge on mucopolysaccharidoses. The e-clinic is the interactive portion of the software. Within an environment resembling a real clinic, the trainee will be instructed to carry out a standard history, examine the patient, and order appropriate tests. The software provides real patient data, such as urine MPS, radiograph and TLC plate. The trainee will be then questioned and provided with a final score, along with performance feedback. While a trainee is working on a case, he/she can access the e-book through the book icon. In conclusion, our software is an educational tool for independent learning. It adopts the PMP through the eclinic as well as it provides the trainee with comprehensive and thorough information through the illustrative e-book. Website address: http://www.sickkids.ca/lysosomalresearchgroup/
Amelia Ahern-Rindell, Jacob Luty, University of Portland, Portland, OR, United States doi:10.1016/j.ymgme.2008.11.004 GM1-gangliosidosis (GM1) is an untreatable, neurodegenerative lysosomal storage disease that has been identified in several mammalian species. GM1 is the result of mutations in the GLB1 gene that impair the function of lysosomal beta-galactosidase (beta-gal). A unique ovine model of GM1 that presents with a secondary deficiency of another lysosomal enzyme, alpha-neuraminidase (neur), was described but beta-galactosidase from this model was not analyzed until now. The purpose of this investigation was to compare beta-gal from crude homogenates of control and GM1-affected sheep liver using SDS–PAGE and Western blotting with an IgG-antibody raised to a highly conserved, N-terminal beta-gal peptide sequence. Under non-reducing conditions, mutant sheep liver supernatants yielded a putative beta-gal monomer band with a molecular weight of 62-kDa. No such band was present in the crude homogenate of the normal sheep liver. Under reducing conditions, normal and mutant sheep liver supernatants yielded putative monomer bands with molecular weights of 64-kDa and 62-kDa, respectively. The preliminary sheep liver enzyme data suggest that there may be a structural difference between normal and GM1-affected sheep beta-gal. This structural difference may interfere with the ability of the affected sheep beta-gal monomer to dimerize or associate into multimeric forms. These results support our hypothesis that this sheep disorder may be the result of a primary mutation in the GLB1 gene that alters the beta-gal monomer impairing its incorporation into the Lysosomal Multienzyme Complex (LMC). Failed LMC formation could account for the dual deficiency of beta-gal and neur, which are normally protected from premature degradation as components of the complex. Further characterization
4. Phase I trial of pyrimethamine to treat LOTS Bijan Almassian, ExSAR Corporation, Monmouth Junction, NJ, United States Adult Tay-Sachs disease (TSD) and Sandhoff disease (SD) result from a deficiency of lysosomal heterodimeric beta-hexosaminidase A (Hex A, ab). Substantial evidence supports a disease model for TSD and SD which attributes pathology to decreased or absent Hex A levels in neuronal lysosomes of the brain. The problem in GM2 gangliosidosis is the inability of the cell to metabolize GM2-gangliosides. When the residual activity of Hex A falls below a critical threshold level, GM2-ganglioside influx into the lysosome (the site of Hex A activity) exceeds the degradation rate and excess substrate continuously accumulates. Consequently, the lysosomes increase in size and number, giving rise to a storage disease. The majority of the mutations in Hex A affect the ability of the enzyme to obtain and/or retain its native three-dimensional fold in the endoplasmic reticulum (ER) where intracellular quality control is performed to retain and degrade defective enzymes. Pharmacological chaperones (PC)s are small molecules that can stabilize the native conformation of a mutant enzyme in the ER and allow it to escape the ER’s quality control system and its associated degradation pathway (ERAD). PCs have
Contents lists available at ScienceDirect
Molecular Genetics and Metabolism journal homepage: www.elsevier.com/locate/ymgme
Abstracts for the Lysosomal Disease Network’s WORLD Symposium 1. New developments in biomarkers for lysosomal storage disorders Johannes Aerts, Academic Medical Center, Amsterdam, Netherlands
of this unique sheep model may help elucidate the dynamics of the LMC under normal and abnormal circumstances. doi:10.1016/j.ymgme.2008.11.003
A biomarker is generally an analyte that signals the extent of a biological process (e.g., storage cell formation in the case of lysosomal storage disorders), This is itself linked to clinical manifestations and outcome of a disease. A biomarker is preferably detectable in bodily fluids such as plasma or urine. Use of a biomarker may help to improve diagnose and to monitor disease progression and/or correction on therapeutic intervention. The ideal biomarker may assist in clinical management by guiding decision making regarding initiation of therapy and optimal individualized treatment regimens. This presentation discusses biomarker discovery and application using Gaucher disease as illustration. The first potent Gaucher biomarker was the enzyme chitotriosidase that is secreted by pathological lipid-laden macrophages (Gaucher cells) into the circulation. Subsequently, it is was discovered that CCL18/PARC is also secreted by Gaucher cells and offers an excellent alternative to assess the body burden on Gaucher cells. Recently, elevation of the chemokines MIP-1alpha and 1beta was discovered. These proteins are not produced by Gaucher cells but surrounding inflammatory macrophages. Label-free quantitative proteomics, LCMSE, allows detection of clear abnormalities in complement and coagulation cascades in symptomatic Gaucher patients, being responsive to therapy. Next to proteins, primary and secondary lipid abnormalities have also potential value as markers. Besides increased glucosylceramide, plasma of Gaucher patients contains increased ganglioside GM3. In the case of Fabry disease, a dramatic elevation in a metabolite, globotriaosylsphingosine of the primary storage lipid globotriosylceramide was recently discovered. This metabolite may play a role in vascular remodelling in patients and thus constitute a risk factor for pathogenesis. Recent data on the predictive value of plasma globotriaosylsphingosine will be presented in conclusion, biomarkers play an increasing role in guidance of clinical management and may also improve our understanding of pathophysiological events. doi:10.1016/j.ymgme.2008.11.002
2. Analysis of beta-galactosidase in an ovine model of GM1-gangliosidosis
3. Computer-assisted teaching of mucopolysaccharidosis by patient management problems Fatma Al-Jasmi, Laura Moldovan, Joe Clarke, Hospital for Sick Children, Toronto, On, Canada Background: Computer-assisted teaching holds significant promise for meeting the current demands and challenges of medical education by providing comprehensive, consistent and quality teaching materials from any location and at any time. Computer-assisted patient management problems (PMP) are well-known educational device and it has been used extensively in teaching in other areas. However; it has never been applied systematically to the teaching of inborn error of metabolism. Aim: To develop interactive teaching software for independent learning about the management of mucopolysaccharidoses, targeted to be used as a self-training by the general physicians. Method and result: The software consists of two main parts: the e-book and the clinic. The e-book contains six sections: overview, biochemistry, genetics, clinical manifestations, diagnosis and management. The e-book is visual illustrative with basic and clinical knowledge that is delivered to the trainee in simple and attractive way. All references are hyperlinked to PubMed and websites, for those needing further information or clarification. Through the contained hyperlinks the trainee has the opportunity to build further on the knowledge on mucopolysaccharidoses. The e-clinic is the interactive portion of the software. Within an environment resembling a real clinic, the trainee will be instructed to carry out a standard history, examine the patient, and order appropriate tests. The software provides real patient data, such as urine MPS, radiograph and TLC plate. The trainee will be then questioned and provided with a final score, along with performance feedback. While a trainee is working on a case, he/she can access the e-book through the book icon. In conclusion, our software is an educational tool for independent learning. It adopts the PMP through the eclinic as well as it provides the trainee with comprehensive and thorough information through the illustrative e-book. Website address: http://www.sickkids.ca/lysosomalresearchgroup/
Amelia Ahern-Rindell, Jacob Luty, University of Portland, Portland, OR, United States doi:10.1016/j.ymgme.2008.11.004 GM1-gangliosidosis (GM1) is an untreatable, neurodegenerative lysosomal storage disease that has been identified in several mammalian species. GM1 is the result of mutations in the GLB1 gene that impair the function of lysosomal beta-galactosidase (beta-gal). A unique ovine model of GM1 that presents with a secondary deficiency of another lysosomal enzyme, alpha-neuraminidase (neur), was described but beta-galactosidase from this model was not analyzed until now. The purpose of this investigation was to compare beta-gal from crude homogenates of control and GM1-affected sheep liver using SDS–PAGE and Western blotting with an IgG-antibody raised to a highly conserved, N-terminal beta-gal peptide sequence. Under non-reducing conditions, mutant sheep liver supernatants yielded a putative beta-gal monomer band with a molecular weight of 62-kDa. No such band was present in the crude homogenate of the normal sheep liver. Under reducing conditions, normal and mutant sheep liver supernatants yielded putative monomer bands with molecular weights of 64-kDa and 62-kDa, respectively. The preliminary sheep liver enzyme data suggest that there may be a structural difference between normal and GM1-affected sheep beta-gal. This structural difference may interfere with the ability of the affected sheep beta-gal monomer to dimerize or associate into multimeric forms. These results support our hypothesis that this sheep disorder may be the result of a primary mutation in the GLB1 gene that alters the beta-gal monomer impairing its incorporation into the Lysosomal Multienzyme Complex (LMC). Failed LMC formation could account for the dual deficiency of beta-gal and neur, which are normally protected from premature degradation as components of the complex. Further characterization
4. Phase I trial of pyrimethamine to treat LOTS Bijan Almassian, ExSAR Corporation, Monmouth Junction, NJ, United States Adult Tay-Sachs disease (TSD) and Sandhoff disease (SD) result from a deficiency of lysosomal heterodimeric beta-hexosaminidase A (Hex A, ab). Substantial evidence supports a disease model for TSD and SD which attributes pathology to decreased or absent Hex A levels in neuronal lysosomes of the brain. The problem in GM2 gangliosidosis is the inability of the cell to metabolize GM2-gangliosides. When the residual activity of Hex A falls below a critical threshold level, GM2-ganglioside influx into the lysosome (the site of Hex A activity) exceeds the degradation rate and excess substrate continuously accumulates. Consequently, the lysosomes increase in size and number, giving rise to a storage disease. The majority of the mutations in Hex A affect the ability of the enzyme to obtain and/or retain its native three-dimensional fold in the endoplasmic reticulum (ER) where intracellular quality control is performed to retain and degrade defective enzymes. Pharmacological chaperones (PC)s are small molecules that can stabilize the native conformation of a mutant enzyme in the ER and allow it to escape the ER’s quality control system and its associated degradation pathway (ERAD). PCs have