Ornithine transcarbamylase （OTC） deficiency is an X-linked trait that accounts for nearly half of all inherited disorders of the urea cycle. OTC is one of the enzymes common to both the urea cycle and the bacterial ...Ornithine transcarbamylase （OTC） deficiency is an X-linked trait that accounts for nearly half of all inherited disorders of the urea cycle. OTC is one of the enzymes common to both the urea cycle and the bacterial arginine biosynthesis pathway; however, the role of OTC has changed over evolution. For animals with a urea cycle, defects in OTC can trigger hyperammonemic episodes that can lead to brain damage and death. This is the fifth mutation update for human OTC with previous updates reported in 1993, 1995, 2002, and 2006. In the 2006 update, 341 mutations were reported. This current update contains 417 disease-causing mutations, and also is the first report of this series to incorporate information about natural variation of the OTC gene in the general population through examination of publicly available genomic data and examination of phenotype/genotype correlations from patients participating in the Urea Cycle Disorders Consortium Longitudinal Study and the first to evaluate the suitability of systematic computational approaches to predict severity of disease associated with different types of OTC mutations.展开更多
Bi-directional translocation and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycelium were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices...Bi-directional translocation and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycelium were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N- and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra- phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those in nitrate or exogenous Arg; however, glycerol supplied as an external car- bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio- synthesized in the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks. Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either in the mycorrhizal compartment or in the fungal compartment. Once Arg was translo- cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled in the fungal compartment, respectively. Evidently Orn formation indi- cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.展开更多
Alzheimer’s disease is an incurable chronic neurodegenerative disorder and the leading cause of dementia,imposing a growing economic burden upon society.The disease progression is associated with gradual deposition o...Alzheimer’s disease is an incurable chronic neurodegenerative disorder and the leading cause of dementia,imposing a growing economic burden upon society.The disease progression is associated with gradual deposition of amyloid plaques and the formation of neurofibrillary tangles within the brain parenchyma,yet severe dementia is the culminating phase of the enduring pathology.Converging evidence suggests that Alzheimer’s disease-related cognitive decline is the outcome of an extremely complex and persistent pathophysiological process.The disease is characterized by distinctive abnormalities apparent at systemic,histological,macromolecular,and biochemical levels.Moreover,besides the well-defined and self-evident characteristic profuse neurofibrillary tangles,dystrophic neurites,and amyloid-beta deposits,the Alzheimer’s disease-associated pathology includes neuroinflammation,substantial neuronal loss,apoptosis,extensive DNA damage,considerable mitochondrial malfunction,compromised energy metabolism,and chronic oxidative stress.Likewise,distinctive metabolic dysfunction has been named a leading cause and a hallmark of Alzheimer’s disease that is apparent decades prior to disease manifestation.State-of-theart metabolomics studies demonstrate that altered branched-chain amino acids(BCAAs)metabolism accompanies Alzheimer’s disease development.Lower plasma valine levels are correlated with accelerated cognitive decline,and,conversely,an increase in valine concentration is associated with reduced risk of Alzheimer’s disease.Additionally,a clear BCAAs-related metabolic signature has been identified in subjects with obesity,diabetes,and atherosclerosis.Also,arginine metabolism is dramatically altered in Alzheimer’s disease human brains and animal models.Accordingly,a potential role of the urea cycle in the Alzheimer’s disease development has been hypothesized,and preclinical studies utilizing intervention in the urea cycle and/or BCAAs metabolism have demonstrated clinical potential.Continual failures to off展开更多
Growing evidence highlights the role of arginase activity in the manifestation of Alzheimer’s disease(AD).Upregulation of arginase was shown to contribute to neurodegeneration.Regulation of arginase activity appears ...Growing evidence highlights the role of arginase activity in the manifestation of Alzheimer’s disease(AD).Upregulation of arginase was shown to contribute to neurodegeneration.Regulation of arginase activity appears to be a promising approach for interfering with the pathogenesis of AD.Therefore,the enzyme represents a novel therapeutic target.In this study,we administered an arginase inhibitor,L-norvaline(250 mg/L),for 2.5 months to a triple-transgenic model(3×Tg-AD)harboring PS1M146V,APPSwe,and tauP301L transgenes.Then,the neuroprotective effects of L-norvaline were evaluated using immunohistochemistry,proteomics,and quantitative polymerase chain reaction assays.Finally,we identified the biological pathways activated by the treatment.Remarkably,L-norvaline treatment reverses the cognitive decline in AD mice.The treatment is neuroprotective as indicated by reduced beta-amyloidosis,alleviated microgliosis,and reduced tumor necrosis factor transcription levels.Moreover,elevated levels of neuroplasticity related postsynaptic density protein 95 were detected in the hippocampi of mice treated with L-norvaline.Furthermore,we disclosed several biological pathways,which were involved in cell survival and neuroplasticity and were activated by the treatment.Through these modes of action,L-norvaline has the potential to improve the symptoms of AD and even interferes with its pathogenesis.As such,L-norvaline is a promising neuroprotective molecule that might be tailored for the treatment of a range of neurodegenerative disorders.The study was approved by the Bar-Ilan University Animal Care and Use Committee(approval No.82-10-2017)on October 1,2017.展开更多
BACKGROUND Ornithine transcarbamylase deficiency(OTCD)is an X-linked inherited disorder and characterized by marked elevation of blood ammonia.The goal of treatment is to minimize the neurological damage caused by hyp...BACKGROUND Ornithine transcarbamylase deficiency(OTCD)is an X-linked inherited disorder and characterized by marked elevation of blood ammonia.The goal of treatment is to minimize the neurological damage caused by hyperammonemia.OTCD can be cured by liver transplantation(LT).Post-transplant patients can discontinue anti-hyperammonemia agents and consume a regular diet without the risk of developing hyperammonemia.The neurological damage caused by hyperammonemia is almost irreversible.CASE SUMMARY An 11.7-year-old boy presented with headache,vomiting,and altered consciousness.The patient was diagnosed with late-onset OTCD.After nitrogen scavenging treatment and a protein-free diet,ammonia levels were reduced to normal on the third day of admission.Nevertheless,the patient remained in a moderate coma.After discussion,LT was performed.Following LT,the patient’s blood ammonia and biochemical indicators stabilized in the normal range,he regained consciousness,and his nervous system function significantly recovered.Two months after LT,blood amino acids and urine organic acids were normal,and brain magnetic resonance imaging showed a decrease in subcortical lesions.CONCLUSION LT can significantly improve partial neurological impairment caused by late-onset OTCD hyperammonemic encephalopathy,and LT can be actively considered when early drug therapy is ineffective.展开更多
Ornithine transcarbamylase deficiency(OTCD) is an X-linked disorder,with an estimated prevalence of 1 per 80000 live births.Female patients with OTCD develop metabolic crises that are easily provoked by non-predictabl...Ornithine transcarbamylase deficiency(OTCD) is an X-linked disorder,with an estimated prevalence of 1 per 80000 live births.Female patients with OTCD develop metabolic crises that are easily provoked by non-predictable common disorders,such as genetic(private mutations and lyonization) and external factors;however,the outcomes of these conditions may differ.We resuscitated a female patient with OTCD from hyperammonemic crisis after she gave birth.Hyperammonemia after parturition in a female patient with OTCD can be fatal,and this type of hyperammonemia persists for an extended period of time.Here,we describe the cause and treatment of hyperammonemia in a female patient with OTCD after parturition.Once hyperammonemia crisis occurs after giving birth,it is difficult to improve the metabolic state.Therefore,it is important to perform an early intervention before hyperammonemia occurs in patients with OTCD or in carriers after parturition.展开更多
基金the support of the Kettering Family FoundationThe Urea Cycle Disorders Consortium (U54HD061221) is a part of the National Institutes of Health (NIH) Rare Disease Clinical Research Network (RDCRN)+3 种基金supported through collaboration between the Office of Rare Diseases Research (ORDR)the National Center for Advancing Translational Science (NCATS)the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)The Urea Cycle Disorders Consortium is also supported by the O’Malley Foundation, the Rotenberg Family Fund, the Dietmar-Hopp Foundation, and the Kettering Fund
文摘Ornithine transcarbamylase （OTC） deficiency is an X-linked trait that accounts for nearly half of all inherited disorders of the urea cycle. OTC is one of the enzymes common to both the urea cycle and the bacterial arginine biosynthesis pathway; however, the role of OTC has changed over evolution. For animals with a urea cycle, defects in OTC can trigger hyperammonemic episodes that can lead to brain damage and death. This is the fifth mutation update for human OTC with previous updates reported in 1993, 1995, 2002, and 2006. In the 2006 update, 341 mutations were reported. This current update contains 417 disease-causing mutations, and also is the first report of this series to incorporate information about natural variation of the OTC gene in the general population through examination of publicly available genomic data and examination of phenotype/genotype correlations from patients participating in the Urea Cycle Disorders Consortium Longitudinal Study and the first to evaluate the suitability of systematic computational approaches to predict severity of disease associated with different types of OTC mutations.
基金Supported by Science and Technology Department of Zhejiang Province (Grant No. 2006C22009).
文摘Bi-directional translocation and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycelium were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N- and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra- phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those in nitrate or exogenous Arg; however, glycerol supplied as an external car- bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio- synthesized in the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks. Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either in the mycorrhizal compartment or in the fungal compartment. Once Arg was translo- cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled in the fungal compartment, respectively. Evidently Orn formation indi- cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.
基金supported by a Marie Curie CIG Grant 322113a Leir Foundation Grant+1 种基金a Ginzburg Family Foundation Granta Katz Foundation Grant to AOS
文摘Alzheimer’s disease is an incurable chronic neurodegenerative disorder and the leading cause of dementia,imposing a growing economic burden upon society.The disease progression is associated with gradual deposition of amyloid plaques and the formation of neurofibrillary tangles within the brain parenchyma,yet severe dementia is the culminating phase of the enduring pathology.Converging evidence suggests that Alzheimer’s disease-related cognitive decline is the outcome of an extremely complex and persistent pathophysiological process.The disease is characterized by distinctive abnormalities apparent at systemic,histological,macromolecular,and biochemical levels.Moreover,besides the well-defined and self-evident characteristic profuse neurofibrillary tangles,dystrophic neurites,and amyloid-beta deposits,the Alzheimer’s disease-associated pathology includes neuroinflammation,substantial neuronal loss,apoptosis,extensive DNA damage,considerable mitochondrial malfunction,compromised energy metabolism,and chronic oxidative stress.Likewise,distinctive metabolic dysfunction has been named a leading cause and a hallmark of Alzheimer’s disease that is apparent decades prior to disease manifestation.State-of-theart metabolomics studies demonstrate that altered branched-chain amino acids(BCAAs)metabolism accompanies Alzheimer’s disease development.Lower plasma valine levels are correlated with accelerated cognitive decline,and,conversely,an increase in valine concentration is associated with reduced risk of Alzheimer’s disease.Additionally,a clear BCAAs-related metabolic signature has been identified in subjects with obesity,diabetes,and atherosclerosis.Also,arginine metabolism is dramatically altered in Alzheimer’s disease human brains and animal models.Accordingly,a potential role of the urea cycle in the Alzheimer’s disease development has been hypothesized,and preclinical studies utilizing intervention in the urea cycle and/or BCAAs metabolism have demonstrated clinical potential.Continual failures to off
基金supported by Marie Curie CIG Grant 322113Leir Foundation Grant+1 种基金Ginzburg Family Foundation GrantKatz Foundation Grant(all to AOS)
文摘Growing evidence highlights the role of arginase activity in the manifestation of Alzheimer’s disease(AD).Upregulation of arginase was shown to contribute to neurodegeneration.Regulation of arginase activity appears to be a promising approach for interfering with the pathogenesis of AD.Therefore,the enzyme represents a novel therapeutic target.In this study,we administered an arginase inhibitor,L-norvaline(250 mg/L),for 2.5 months to a triple-transgenic model(3×Tg-AD)harboring PS1M146V,APPSwe,and tauP301L transgenes.Then,the neuroprotective effects of L-norvaline were evaluated using immunohistochemistry,proteomics,and quantitative polymerase chain reaction assays.Finally,we identified the biological pathways activated by the treatment.Remarkably,L-norvaline treatment reverses the cognitive decline in AD mice.The treatment is neuroprotective as indicated by reduced beta-amyloidosis,alleviated microgliosis,and reduced tumor necrosis factor transcription levels.Moreover,elevated levels of neuroplasticity related postsynaptic density protein 95 were detected in the hippocampi of mice treated with L-norvaline.Furthermore,we disclosed several biological pathways,which were involved in cell survival and neuroplasticity and were activated by the treatment.Through these modes of action,L-norvaline has the potential to improve the symptoms of AD and even interferes with its pathogenesis.As such,L-norvaline is a promising neuroprotective molecule that might be tailored for the treatment of a range of neurodegenerative disorders.The study was approved by the Bar-Ilan University Animal Care and Use Committee(approval No.82-10-2017)on October 1,2017.
基金Supported by the Sanming Project of Medicine in Shenzhen,No.SZSM201812005。
文摘BACKGROUND Ornithine transcarbamylase deficiency(OTCD)is an X-linked inherited disorder and characterized by marked elevation of blood ammonia.The goal of treatment is to minimize the neurological damage caused by hyperammonemia.OTCD can be cured by liver transplantation(LT).Post-transplant patients can discontinue anti-hyperammonemia agents and consume a regular diet without the risk of developing hyperammonemia.The neurological damage caused by hyperammonemia is almost irreversible.CASE SUMMARY An 11.7-year-old boy presented with headache,vomiting,and altered consciousness.The patient was diagnosed with late-onset OTCD.After nitrogen scavenging treatment and a protein-free diet,ammonia levels were reduced to normal on the third day of admission.Nevertheless,the patient remained in a moderate coma.After discussion,LT was performed.Following LT,the patient’s blood ammonia and biochemical indicators stabilized in the normal range,he regained consciousness,and his nervous system function significantly recovered.Two months after LT,blood amino acids and urine organic acids were normal,and brain magnetic resonance imaging showed a decrease in subcortical lesions.CONCLUSION LT can significantly improve partial neurological impairment caused by late-onset OTCD hyperammonemic encephalopathy,and LT can be actively considered when early drug therapy is ineffective.
基金Supported by A Grant-in-Aid for Guidelines and Lifetime Medical Support Systems for inborn errors of metabolism found by newborn screeninga Grant-in-Aid for the Practical Research Project for Rare/Intractable Diseases from Japan Agency for Medical Research and Development,AMED
文摘Ornithine transcarbamylase deficiency(OTCD) is an X-linked disorder,with an estimated prevalence of 1 per 80000 live births.Female patients with OTCD develop metabolic crises that are easily provoked by non-predictable common disorders,such as genetic(private mutations and lyonization) and external factors;however,the outcomes of these conditions may differ.We resuscitated a female patient with OTCD from hyperammonemic crisis after she gave birth.Hyperammonemia after parturition in a female patient with OTCD can be fatal,and this type of hyperammonemia persists for an extended period of time.Here,we describe the cause and treatment of hyperammonemia in a female patient with OTCD after parturition.Once hyperammonemia crisis occurs after giving birth,it is difficult to improve the metabolic state.Therefore,it is important to perform an early intervention before hyperammonemia occurs in patients with OTCD or in carriers after parturition.
