- Email: [email protected]
Inhibiting glycogen biosynthesis by mTORC1 suppression as an adjunct therapy for Pompe disease
S30
Abstracts / Molecular Genetics and Metabolism 102 (2011) S3–S47
Conclusion: This novel method has the required sensitivity and specificity to determine pre- and post-treatment levels of GAGs in CSF and provides a means of monitoring patients on IT-ERT. doi:10.1016/j.ymgme.2010.11.099
A phase II, randomized, controlled trial of Mycophenolate Mofetil in children with juvenile NCL (JNCL) Jonathan Mink, Erika F. Augustine, Heather Adams, Nicole J. Newhouse, Amy Vierhile, Elisabeth A. deBlieck, Jennifer Cialone, Frederick J. Marshall, University of Rochester, Rochester, NY, USA JNCL is a fatal neurodegenerative disorder of childhood. Current treatment is symptomatic and only effective for some symptoms. Preliminary data on immuno-suppression CLN3-knockout mice is supportive of a disease-altering strategy for treating JNCL with an immuno-suppressive agent. Mycophenolate mofetil (MMF) is used to prevent organ transplant rejection and is approved by the FDA for pediatric use. We are beginning a phase II trial of MMF in children with JNCL. Objectives are: 1) to establish the safety and tolerability of shortterm administration of mycophenolate mofetil in ambulatory children with JNCL; 2) to gather preliminary evidence of the short-term impact of mycophenolate mofetil on clinically relevant features of JNCL; and 3) to pilot the feasibility of conducting controlled clinical trials of this rare neurological disorder based on collaboration between a national center of excellence in the disease, and children's local care-providers. We designed a double-blind, randomized, 22-week cross-over study of mycophenolate mofetil vs. placebo. After a 4-week washout period, subjects will undergo blinded crossover from active study drug to placebo or from placebo to active study drug. Outcome measures include: 1) tolerability, defined as the proportion of subjects able to complete 8 weeks on the assigned dosage of study drug versus those able to complete 8 weeks on placebo; 2) change in the Batten Disease Rating Scale score and cognitive performance. This represents the first controlled trial in JNCL. The collaborative design represents a novel model for experimental therapeutics in rare childhood neurodegenerative diseases. doi:10.1016/j.ymgme.2010.11.100
GBA1 deficient mice recapitulates Gaucher disease displaying system-wide cellular and molecular dysregulation beyond the macrophage
Q23 Q24 Q25
Pramod Mistrya, Jun Liua, Harry Blairb, Joan Keutzerd, Kate Zhangd, Li Sunc, Mone Zaidic, aYale University, New Haven, CT, USA, bUniversity of Pittsburgh, Pisstburgh, PA, USA, cMount Sinai School of Medicine, NY, NY, USA, dGenzyme Corporation, Cambridge, MA, USA Background: In Gaucher's disease (GD), GBA1 gene mutations result in the deficiency of glucocerebrosidase and lysosomal accumulation of glucocerebroside in macrophages (M). The prevailing M-centric view, however, does not explain numerous aspects of the disease that are refractory to M-directed enzyme therapy. Methods: To understand the pathophysiology of GD, we conditionally deleted the GBA1 gene in the hematopoetic and mesenchymal cell lineages using Mx1 promoter. Results: GD1 mice exhibited a striking accumulation of glucocerebroside (GL1) and glucosylsphingosine (Lyso GL1). Hepatomegaly and splenomegaly was associated with 5-50X elevation of 296 and 95 genes respectively, representing immune response, signaling, apoptosis, cell cycle and lipid metabolism pathways. Micro-CT revealed decreased trabecular volume, trabecular thinning and loss, accom-
panied, on calcein labeling, with reduced mineral apposition rates in GBA1 mice. Unexpectedly, we found severe osteoporosis arose from a defect in osteoblastic bone formation secondary to inhibition of protein kinase C (PKC); this effect was mediated by LysoGL1 but not of GL1. Contrary to the prevailing view, osteoclastic resorption in vivo and TRAP-positive osteoclast formation ex vivo remained unaffected in GBA1 deficiency. Cytokine measurements, microarray, and immunophenotyping revealed a widespread dysfunction not only in macrophages, but also in thymic T- and B-cell, and dendritic cells. Moreover, bile lipid measurements revealed remarkable capacity for biliary secretion of Lyso GL1 and GL1 in GBA1 deficient mice. Conclusions: Our study provides a clear demonstration for the involvement of cell lineages other than macrophages and LysoGL1mediated inhibition of PKC in the pathophysiology of GD. Important therapeutic implications may eventually follow. doi:10.1016/j.ymgme.2010.11.101
Inhibiting glycogen biosynthesis by mTORC1 suppression as an adjunct therapy for Pompe disease Rodney Moreland, Kristin Taylor, Karen Ashe, Elizabeth Meyers, Allen Ellis, Varvara Jingozyan, Patrick Finn, Seng Cheng, Katherine Klinger, John Marshall, John McPherson, Robert Mattaliano, Ronald Scheule, Genzyme, Framingham, MA, USA Pompe disease, also known as glycogen storage disease (GSD) type II, is caused by deficiency of lysosomal acid -glucosidase (GAA). The resulting glycogen accumulation causes a spectrum of disease severity ranging from a rapidly progressive course that is typically fatal by 1 to 2 years of age to a more slowly progressive course that causes significant morbidity and early mortality in children and adults. As an enzyme replacement therapy (ERT), recombinant human GAA (rhGAA) improves clinical outcomes with variable results. An adjunct therapy that increases the effectiveness of rhGAA may benefit some Pompe patients. We have examined the biochemical pathways regulating glycogen accumulation in muscle tissue of GAA-/- mice and evaluated the efficacy of small molecule inhibitors of these pathways combined with ERT. It has been reported that in cultured muscle cells glycogen synthase activity can be partially regulated by the mammalian target of rapamycin (mTOR). mTOR is a conserved serine/threonine kinase that exists in several distinct multiprotein complexes such as mTORC1 (containing raptor) and mTORC2 (containing rictor). Rapamycin bound to FKBP12 inhibits mTORC1. Unexpectedly, we found the ubiquitous mTORC1 pathway in vivo robustly regulates glycogen synthesis in skeletal muscle but does not affect glycogen synthesis in liver. We also found that the mTORC1 pathway has a minimal effect on glycogen synthesis in heart and diaphragm. To our knowledge these organ-specific differences in the mTORC1 pathway have not previously been reported. Our findings suggest that mTORC1 inhibition with rapamycin may benefit GSDs that involve glycogen accumulation in skeletal muscle. doi:10.1016/j.ymgme.2010.11.102
Pilot studies of telephone surveillance for health, developmental and disability status and family supports for children with lysosomal storage disorders Michael Msalla, Sarah Bauera, Nancy Lyonb, Patricia Duffnerc, Chester Whitleyd, aJ. P. Kennedy Research Center on Intellectual and Developmental Disabilities, Section of Developmental Pediatrics, University of Chicago Comer & La Rabida Children's Hospitals, Chicago, IL, Chicago, IL,
Abstracts / Molecular Genetics and Metabolism 102 (2011) S3–S47
Conclusion: This novel method has the required sensitivity and specificity to determine pre- and post-treatment levels of GAGs in CSF and provides a means of monitoring patients on IT-ERT. doi:10.1016/j.ymgme.2010.11.099
A phase II, randomized, controlled trial of Mycophenolate Mofetil in children with juvenile NCL (JNCL) Jonathan Mink, Erika F. Augustine, Heather Adams, Nicole J. Newhouse, Amy Vierhile, Elisabeth A. deBlieck, Jennifer Cialone, Frederick J. Marshall, University of Rochester, Rochester, NY, USA JNCL is a fatal neurodegenerative disorder of childhood. Current treatment is symptomatic and only effective for some symptoms. Preliminary data on immuno-suppression CLN3-knockout mice is supportive of a disease-altering strategy for treating JNCL with an immuno-suppressive agent. Mycophenolate mofetil (MMF) is used to prevent organ transplant rejection and is approved by the FDA for pediatric use. We are beginning a phase II trial of MMF in children with JNCL. Objectives are: 1) to establish the safety and tolerability of shortterm administration of mycophenolate mofetil in ambulatory children with JNCL; 2) to gather preliminary evidence of the short-term impact of mycophenolate mofetil on clinically relevant features of JNCL; and 3) to pilot the feasibility of conducting controlled clinical trials of this rare neurological disorder based on collaboration between a national center of excellence in the disease, and children's local care-providers. We designed a double-blind, randomized, 22-week cross-over study of mycophenolate mofetil vs. placebo. After a 4-week washout period, subjects will undergo blinded crossover from active study drug to placebo or from placebo to active study drug. Outcome measures include: 1) tolerability, defined as the proportion of subjects able to complete 8 weeks on the assigned dosage of study drug versus those able to complete 8 weeks on placebo; 2) change in the Batten Disease Rating Scale score and cognitive performance. This represents the first controlled trial in JNCL. The collaborative design represents a novel model for experimental therapeutics in rare childhood neurodegenerative diseases. doi:10.1016/j.ymgme.2010.11.100
GBA1 deficient mice recapitulates Gaucher disease displaying system-wide cellular and molecular dysregulation beyond the macrophage
Q23 Q24 Q25
Pramod Mistrya, Jun Liua, Harry Blairb, Joan Keutzerd, Kate Zhangd, Li Sunc, Mone Zaidic, aYale University, New Haven, CT, USA, bUniversity of Pittsburgh, Pisstburgh, PA, USA, cMount Sinai School of Medicine, NY, NY, USA, dGenzyme Corporation, Cambridge, MA, USA Background: In Gaucher's disease (GD), GBA1 gene mutations result in the deficiency of glucocerebrosidase and lysosomal accumulation of glucocerebroside in macrophages (M). The prevailing M-centric view, however, does not explain numerous aspects of the disease that are refractory to M-directed enzyme therapy. Methods: To understand the pathophysiology of GD, we conditionally deleted the GBA1 gene in the hematopoetic and mesenchymal cell lineages using Mx1 promoter. Results: GD1 mice exhibited a striking accumulation of glucocerebroside (GL1) and glucosylsphingosine (Lyso GL1). Hepatomegaly and splenomegaly was associated with 5-50X elevation of 296 and 95 genes respectively, representing immune response, signaling, apoptosis, cell cycle and lipid metabolism pathways. Micro-CT revealed decreased trabecular volume, trabecular thinning and loss, accom-
panied, on calcein labeling, with reduced mineral apposition rates in GBA1 mice. Unexpectedly, we found severe osteoporosis arose from a defect in osteoblastic bone formation secondary to inhibition of protein kinase C (PKC); this effect was mediated by LysoGL1 but not of GL1. Contrary to the prevailing view, osteoclastic resorption in vivo and TRAP-positive osteoclast formation ex vivo remained unaffected in GBA1 deficiency. Cytokine measurements, microarray, and immunophenotyping revealed a widespread dysfunction not only in macrophages, but also in thymic T- and B-cell, and dendritic cells. Moreover, bile lipid measurements revealed remarkable capacity for biliary secretion of Lyso GL1 and GL1 in GBA1 deficient mice. Conclusions: Our study provides a clear demonstration for the involvement of cell lineages other than macrophages and LysoGL1mediated inhibition of PKC in the pathophysiology of GD. Important therapeutic implications may eventually follow. doi:10.1016/j.ymgme.2010.11.101
Inhibiting glycogen biosynthesis by mTORC1 suppression as an adjunct therapy for Pompe disease Rodney Moreland, Kristin Taylor, Karen Ashe, Elizabeth Meyers, Allen Ellis, Varvara Jingozyan, Patrick Finn, Seng Cheng, Katherine Klinger, John Marshall, John McPherson, Robert Mattaliano, Ronald Scheule, Genzyme, Framingham, MA, USA Pompe disease, also known as glycogen storage disease (GSD) type II, is caused by deficiency of lysosomal acid -glucosidase (GAA). The resulting glycogen accumulation causes a spectrum of disease severity ranging from a rapidly progressive course that is typically fatal by 1 to 2 years of age to a more slowly progressive course that causes significant morbidity and early mortality in children and adults. As an enzyme replacement therapy (ERT), recombinant human GAA (rhGAA) improves clinical outcomes with variable results. An adjunct therapy that increases the effectiveness of rhGAA may benefit some Pompe patients. We have examined the biochemical pathways regulating glycogen accumulation in muscle tissue of GAA-/- mice and evaluated the efficacy of small molecule inhibitors of these pathways combined with ERT. It has been reported that in cultured muscle cells glycogen synthase activity can be partially regulated by the mammalian target of rapamycin (mTOR). mTOR is a conserved serine/threonine kinase that exists in several distinct multiprotein complexes such as mTORC1 (containing raptor) and mTORC2 (containing rictor). Rapamycin bound to FKBP12 inhibits mTORC1. Unexpectedly, we found the ubiquitous mTORC1 pathway in vivo robustly regulates glycogen synthesis in skeletal muscle but does not affect glycogen synthesis in liver. We also found that the mTORC1 pathway has a minimal effect on glycogen synthesis in heart and diaphragm. To our knowledge these organ-specific differences in the mTORC1 pathway have not previously been reported. Our findings suggest that mTORC1 inhibition with rapamycin may benefit GSDs that involve glycogen accumulation in skeletal muscle. doi:10.1016/j.ymgme.2010.11.102
Pilot studies of telephone surveillance for health, developmental and disability status and family supports for children with lysosomal storage disorders Michael Msalla, Sarah Bauera, Nancy Lyonb, Patricia Duffnerc, Chester Whitleyd, aJ. P. Kennedy Research Center on Intellectual and Developmental Disabilities, Section of Developmental Pediatrics, University of Chicago Comer & La Rabida Children's Hospitals, Chicago, IL, Chicago, IL,