1F, G, K) and J

1F, G, K) and J. mice, followed by histologic assessment of brain development. We observed that decreasing ODC activity and putrescine levels in mice worsened many of the neurodevelopmental Phellodendrine phenotypes, Phellodendrine including brain growth and neuronal migration defects, astrogliosis and oxidative stress. These data suggest a protective effect of increased ODC activity and elevated putrescine that change the phenotype in this developmental model. Introduction The tuberous sclerosis complex (TSC) (OMIM 191100, 613?254) is a rare autosomal dominant disease that often causes substantial central nervous system pathology. Brain phenotypes include cortical tubers, subependymal nodules (SENs), subependymal giant cell astrocytomas (SEGAs) and other morphologic abnormalities. Morbidity and mortality are often due to epilepsy, intellectual disability, autism spectrum disorders and neuropsychiatric disease (1). TSC is usually caused by inactivating variants in either or or induces an anabolic state with an increase in nucleotide, protein, lipid and other macromolecular synthesis to gas cell growth and proliferation (5). A hallmark of TSC is the intrafamilial and interfamilial variable expressivity among patients. A patient can remain undiagnosed due to relatively benign symptoms, only to be diagnosed after using a severely affected child suffering from recalcitrant epilepsy and developmental delay. While some of the variable expressivity is due to specific pathogenic variants in or (6,7), limited success has been made in associating disease variability with specific or mutations, degree of mosaicism, genetic modifiers and environmental factors. The identification of novel metabolic targets of mTORC1 hyperactivity may improve our general understanding of TSC biology and its inherent variability. Using a mouse model of TSC in which the gene was conditionally targeted in most developing neurons and glial cells of the CNS (brains (9), with no switch in the downstream polyamine metabolites spermidine or spermine. Polyamines Rabbit Polyclonal to MRPL46 are small aliphatic polycations with diverse biological functions. Due to their positive charge, polyamines can interact with nucleic acids and proteins and regulate specific ion channels, thereby exerting wide-ranging effects on transcription, translation, RNA and protein stability and cell signaling (10). Polyamine synthesis is usually a tightly controlled process including multiple opinions loops, underscoring the biological importance of maintaining proper levels of these metabolites. In eukaryotes, the primary polyamines, putrescine, Phellodendrine spermidine and spermine are synthesized mainly from your amino acid ornithine. ODC, a rate-limiting enzyme in polyamine synthesis, converts ornithine to putrescine. Spermidine and spermine are sequentially produced from putrescine by aminopropylation using decarboxylated S-adenosylmethionine (dcSAM) as the aminopropyl donor and catalyzed by spermidine synthase and spermine synthase, respectively (11) (Fig. 1A). dcSAM is the product of the second rate-limiting enzyme in the pathway, S-adenosylmethionine decarboxylase, the processing and stabilization of which is usually mTORC1-dependent (12). Functionally, polyamines have been shown to play crucial functions in cell growth, proliferation and migration; cellular stress; aging; and neurodegenerative diseases (10,13). The observations that (1) is usually a transcriptional target of proto-oncogene (14), (2) polyamines are involved in cell growth and proliferation and (3) polyamines are upregulated in malignancies have made them a focus of cancer research (15). Currently, multiple clinical studies investigating the therapeutic effects of the irreversible ODC inhibitor 2-difluoromethylornithine (DFMO) on neuroblastoma, astroglioma and other cancers are underway (16C18). Open in a separate windows Physique 1 ODC expression in human TSC tuber and mouse brain. (A) Polyamine synthetic pathway. ODC indicates ornithine decarboxylase; SpdS, spermidine synthase; SpmS, spermine synthase; dcSAM, decarboxylated S-adenosylmethionine; MTA, 5-methylthioadenosine. (B, C) IHC analysis showing intense ODC1 staining in giant cells of cortical tuber tissue (C) compared with adjacent cortical non-tuber tissue (B) from a TSC patient. (DCK, DCK) IHC analysis of ODC1 immunoreactivity in brains of control (D, D, H, H), untreated (E, E, I, I), (F, F, J, J) and DFMO-treated (G, G, K, K) mice. ODC1 immunoreactivity in cortex (E, E) and hippocampal CA1 pyramidal cells (I, I) of untreated mice and appears localized to both the nucleus and cytoplasm (black arrows), in contrast to control animals (D, D, H, H) where expression is usually primarily cytoplasmic (white arrows). haploinsufficiency and DFMO treatment of mice partially reverse ODC expression levels and nuclear localization. DCK show increased magnification of boxed inset fields indicated in DCK, respectively. CL indicates control; RG, mice, we empirically treated heterozygous mice with the ODC inhibitor DFMO. mice have a hippocampal astrogliosis. Amazingly, DFMO treatment dose-dependently reduced hippocampal astrogliosis (9), suggesting a functional result of increased ODC/putrescine in TSC pathology. Based on these data,.injection of 250?mg/kg DFMO from P10 to P21) of mice. brain development. We observed that decreasing ODC activity and putrescine levels in mice worsened many of the neurodevelopmental phenotypes, including brain growth and neuronal migration defects, astrogliosis and oxidative stress. These data suggest a protective effect of increased ODC activity and elevated putrescine that change the phenotype in this developmental model. Introduction The tuberous sclerosis complex (TSC) (OMIM 191100, 613?254) is a rare autosomal dominant disease that often causes substantial central nervous system pathology. Brain phenotypes include cortical tubers, subependymal nodules (SENs), subependymal giant cell astrocytomas (SEGAs) and other morphologic abnormalities. Morbidity and mortality are often due to epilepsy, intellectual disability, autism spectrum disorders and neuropsychiatric disease (1). TSC is usually caused by inactivating variants in either or or induces an anabolic state with an increase in nucleotide, protein, lipid and other macromolecular synthesis to gas cell growth and proliferation (5). A hallmark of TSC is the intrafamilial and interfamilial variable expressivity among patients. A patient can remain undiagnosed due to relatively benign symptoms, only to be diagnosed after using a severely affected child suffering from recalcitrant epilepsy and developmental delay. While some of the variable expressivity is due to specific pathogenic variants in or (6,7), limited success has been made in associating disease variability with specific or mutations, degree of mosaicism, genetic modifiers and environmental factors. The identification of novel metabolic targets of mTORC1 hyperactivity may improve our general understanding of TSC biology and its inherent variability. Using a mouse model of TSC in which the gene was conditionally targeted in most developing neurons and glial cells of the CNS (brains (9), with no switch in the downstream polyamine metabolites spermidine or spermine. Polyamines are small aliphatic polycations with diverse biological functions. Due to their positive charge, polyamines can interact with nucleic acids and proteins and regulate specific ion channels, thereby exerting wide-ranging effects on transcription, translation, RNA and protein stability and cell signaling (10). Polyamine synthesis is usually a tightly controlled process including multiple opinions loops, underscoring the biological importance of maintaining proper levels of these metabolites. In eukaryotes, the primary polyamines, putrescine, spermidine and spermine are synthesized mainly from your amino acid ornithine. ODC, a rate-limiting enzyme in polyamine synthesis, converts ornithine to putrescine. Spermidine and spermine are sequentially produced from putrescine by aminopropylation using decarboxylated S-adenosylmethionine (dcSAM) as the aminopropyl donor and catalyzed by spermidine synthase and spermine synthase, respectively (11) (Fig. 1A). dcSAM is the product of the second rate-limiting enzyme in the pathway, S-adenosylmethionine decarboxylase, the processing and stabilization of which is usually mTORC1-dependent (12). Functionally, polyamines have been shown to play crucial functions in cell growth, proliferation and migration; cellular stress; aging; and Phellodendrine neurodegenerative diseases (10,13). The observations that (1) is usually a transcriptional target of proto-oncogene (14), (2) polyamines are involved in cell growth and proliferation and (3) polyamines are upregulated in malignancies have made them a focus of cancer research (15). Currently, multiple clinical studies investigating the therapeutic effects of the irreversible ODC inhibitor 2-difluoromethylornithine (DFMO) on neuroblastoma, astroglioma and other cancers are underway (16C18). Open in a separate window Physique 1 ODC expression in human TSC tuber and mouse brain. (A) Polyamine synthetic pathway. ODC indicates ornithine decarboxylase; SpdS, spermidine synthase; SpmS, spermine synthase; dcSAM, decarboxylated S-adenosylmethionine; MTA, 5-methylthioadenosine. (B, C) IHC analysis showing intense ODC1 staining in giant cells of cortical tuber tissue (C) compared with adjacent cortical non-tuber tissue (B) from a TSC patient. (DCK, DCK) IHC analysis of ODC1 immunoreactivity in brains of control (D, D, H, H), untreated (E, E, I, I), (F, F, J, J) and DFMO-treated (G, G, K, K) mice. ODC1 immunoreactivity in cortex (E, E).