scholarly journals Multifocal demyelinating motor neuropathy and hamartoma syndrome associated with a de novo PTEN mutation

Neurology ◽  
2018 ◽  
Vol 90 (21) ◽  
pp. e1842-e1848
Author(s):  
Boglarka Bansagi ◽  
Vietxuan Phan ◽  
Mark R. Baker ◽  
Julia O'Sullivan ◽  
Matthew J. Jennings ◽  
...  
Keyword(s):  
De Novo ◽  
Multifocal Motor Neuropathy ◽  
Suppressor Gene ◽  
Autism Spectrum ◽  
Motor Neuropathy ◽  
Label Free ◽  
Proteomic Profiling ◽  
Altered Expression ◽  
Clinical Criteria

ObjectiveTo describe a patient with a multifocal demyelinating motor neuropathy with onset in childhood and a mutation in phosphatase and tensin homolog (PTEN), a tumor suppressor gene associated with inherited tumor susceptibility conditions, macrocephaly, autism, ataxia, tremor, and epilepsy. Functional implications of this protein have been investigated in Parkinson and Alzheimer diseases.MethodsWe performed whole-exome sequencing in the patient's genomic DNA validated by Sanger sequencing. Immunoblotting, in vitro enzymatic assay, and label-free shotgun proteomic profiling were performed in the patient's fibroblasts.ResultsThe predominant clinical presentation of the patient was a childhood onset, asymmetric progressive multifocal motor neuropathy. In addition, he presented with macrocephaly, autism spectrum disorder, and skin hamartomas, considered as clinical criteria for PTEN-related hamartoma tumor syndrome. Extensive tumor screening did not detect any malignancies. We detected a novel de novo heterozygous c.269T>C, p.(Phe90Ser) PTEN variant, which was absent in both parents. The pathogenicity of the variant is supported by altered expression of several PTEN-associated proteins involved in tumorigenesis. Moreover, fibroblasts showed a defect in catalytic activity of PTEN against the secondary substrate, phosphatidylinositol 3,4-trisphosphate. In support of our findings, focal hypermyelination leading to peripheral neuropathy has been reported in PTEN-deficient mice.ConclusionWe describe a novel phenotype, PTEN-associated multifocal demyelinating motor neuropathy with a skin hamartoma syndrome. A similar mechanism may potentially underlie other forms of Charcot-Marie-Tooth disease with involvement of the phosphatidylinositol pathway.

Lipid Labelling in Intact Chloroplasts from Exogenous Nucleotide Precursors

1981 ◽  
Vol 36 (1-2) ◽  
pp. 62-70 ◽  
Author(s):  
Margrit Bertrams ◽  
Käthe Wrage ◽  
Ernst Heinz
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
De Novo ◽  
Membrane System ◽  
Chloroplast Envelope ◽  
Label Free ◽  
Intact Chloroplasts ◽  
Time Required

Abstract De novo-synthesis of glycerolipids in chloroplasts is initiated by a stroma enzyme which catalyzes the formation of lyso-phosphatidic acid from glycerophosphate and acyl-CoA. When these substrates are added to isolated, intact chloroplasts, only glycerophosphate can readily pass through the chloroplast envelope which represents a permeation barrier for acyl-CoA, although higher thioester concentrations destroy this membrane system. At low concentrations of acyl-CoA, which do not impair the envelope, intact chloroplasts metabolize exogenous acyl-CoA in two ways to give free fatty acids and labelled phosphatidyl choline. This indicates that the envelope thioesterase can use exogenous substrates. Isolated, intact chloroplasts fixing radioactive CO2 label free fatty acids and acylglycerols but not galactolipids, since they cannot convert 3-phosphoglycerate into UDP-galactose which in vivo is supplied by the cytoplasm. This cooperation was simulated in vitro by adding all enzymes and cofactors necessary for conversion of 3-phosphoglycerate into UDP-galactose to intact chloro­plasts which then formed labelled monogalactosyl diacylglycerol from labelled CO2. The time required to transfer envelope-made galactolipids from the envelope into thylakoids was studied by incubating intact chloroplasts with radioactive UDP-galactose, subsequent osmotic disruption of organelles with concomitant enzymatic degradation of UDP-galactose followed by separation of envelopes and thylakoids. Only after short times (< 1min) appreciable proportions 920-30%) of radioactive galactolipid export from envelopes into thylakoids.

scholarly journals Haploinsufficiency of autism candidate gene NUAK1 impairs cortical development and behavior

2018 ◽  
Author(s):  
Virginie Courchet ◽  
Amanda J Roberts ◽  
Peggy Del Carmine ◽  
Tommy L. Lewis ◽  
Franck Polleux ◽  
...  
Keyword(s):  
Social Preference ◽  
De Novo ◽  
Sensorimotor Gating ◽  
Learning Task ◽  
Autism Spectrum ◽  
Dominant Negative ◽  
Loss Of Function ◽  
Cortical Connectivity

SUMMARYRecently, numerous rare de novo mutations have been identified in children diagnosed with autism spectrum disorders (ASD). However, despite the predicted loss-of-function nature of some of these de novo mutations, the affected individuals are heterozygous carriers, which would suggest that most of these candidate genes are haploinsufficient and/or that these mutations lead to expression of dominant-negative forms of the protein. Here, we tested this hypothesis with the gene Nuak1, recently identified as a candidate ASD gene and that we previously identified for its role in the development of cortical connectivity. We report that Nuak1 is happloinsufficient in mice in regard to its function in cortical axon branching in vitro and in vivo. Nuak1+/− mice show a combination of abnormal behavioral traits ranging from defective memory consolidation in a spatial learning task, defects in social novelty (but not social preference) and abnormal sensorimotor gating and prepulse inhibition of the startle response. Overall, our results demonstrate that Nuak1 haploinsufficiency leads to defects in the development of cortical connectivity and a complex array of behavorial deficits compatible with ASD, intellectual disability and schizophrenia.

scholarly journals Application of the AMLprofiler Diagnostic Microarray in the South African Setting

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
S. S. Kappala ◽  
M. Alessandrini ◽  
T. Matlhako ◽  
E. Beltchev ◽  
R. Pool ◽  
...  
Keyword(s):  
South Africa ◽  
Bone Marrow ◽  
South African ◽  
De Novo ◽  
Survival Rates ◽  
Gene Profiling ◽  
Response To Treatment ◽  
Altered Expression ◽  
De Novo Aml

Acute myeloid leukemia (AML) is characterized by proliferation of the myeloid lineage and accumulation of immature hematopoietic cells in the bone marrow and is typified by marked heterogeneity both in response to treatment and survival. AMLprofiler is a qualitative in vitro diagnostic microarray incorporating seven molecular biomarkers used to diagnose and predict posttherapy survival rates. In this study, we compared AMLprofiler to routine AML diagnostic methodologies employed in South Africa, focusing on consistency of the results, cost, and time to result. RNA was isolated from bone marrow and peripheral blood samples from patients with de novo AML and was processed using Affymetrix Gene Profiling Reagent kits. The results from AMLprofiler and standard methodologies were highly comparable. In addition, many samples were determined to be positive for biomarkers not routinely investigated in South Africa, namely, CEBPA double mutants, NPM1 variants, and altered expression levels of BAALC and EVI1. 38% of samples presented with no positive biomarker; AMLprofiler nonetheless enabled 26% of AML patients to be classified into either favorable or poor prognostic categories. This study highlights the comprehensive nature of the microarray. Decreased time to result and refinement of risk stratification are notable benefits.

scholarly journals mTOR Driven Gene Transcription Is Required for Cholesterol Production in Neurons of the Developing Cerebral Cortex

2021 ◽  
Vol 22 (11) ◽  
pp. 6034
Author(s):  
Martin Schüle ◽  
Tamer Butto ◽  
Sri Dewi ◽  
Laura Schlichtholz ◽  
Susanne Strand ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Neurodevelopmental Disorders ◽  
Cholesterol Biosynthesis ◽  
Single Gene ◽  
Autism Spectrum ◽  
Altered Expression ◽  
Mtorc1 Signaling ◽  
Mtor Activity

Dysregulated mammalian target of rapamycin (mTOR) activity is associated with various neurodevelopmental disorders ranging from idiopathic autism spectrum disorders (ASD) to syndromes caused by single gene defects. This suggests that maintaining mTOR activity levels in a physiological range is essential for brain development and functioning. Upon activation, mTOR regulates a variety of cellular processes such as cell growth, autophagy, and metabolism. On a molecular level, however, the consequences of mTOR activation in the brain are not well understood. Low levels of cholesterol are associated with a wide variety of neurodevelopmental disorders. We here describe numerous genes of the sterol/cholesterol biosynthesis pathway to be transcriptionally regulated by mTOR complex 1 (mTORC1) signaling in vitro in primary neurons and in vivo in the developing cerebral cortex of the mouse. We find that these genes are shared targets of the transcription factors SREBP, SP1, and NF-Y. Prenatal as well as postnatal mTORC1 inhibition downregulated expression of these genes which directly translated into reduced cholesterol levels, pointing towards a substantial metabolic function of the mTORC1 signaling cascade. Altogether, our results indicate that mTORC1 is an essential transcriptional regulator of the expression of sterol/cholesterol biosynthesis genes in the developing brain. Altered expression of these genes may be an important factor contributing to the pathogenesis of neurodevelopmental disorders associated with dysregulated mTOR signaling.

scholarly journals Cul3 regulates cytoskeleton protein homeostasis and cell migration during a critical window of brain development

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jasmin Morandell ◽  
Lena A. Schwarz ◽  
Bernadette Basilico ◽  
Saren Tasciyan ◽  
Georgi Dimchev ◽  
...  
Keyword(s):  
Cell Migration ◽  
Transcriptional Activation ◽  
Neuronal Migration ◽  
Motor Coordination ◽  
De Novo ◽  
Autism Spectrum ◽  
Loss Of Function ◽  
Critical Window ◽  
Cytoskeleton Organization

AbstractDe novo loss of function mutations in the ubiquitin ligase-encoding gene Cullin3 (CUL3) lead to autism spectrum disorder (ASD). In mouse, constitutive Cul3 haploinsufficiency leads to motor coordination deficits as well as ASD-relevant social and cognitive impairments. However, induction of Cul3 haploinsufficiency later in life does not lead to ASD-relevant behaviors, pointing to an important role of Cul3 during a critical developmental window. Here we show that Cul3 is essential to regulate neuronal migration and, therefore, constitutive Cul3 heterozygous mutant mice display cortical lamination abnormalities. At the molecular level, we found that Cul3 controls neuronal migration by tightly regulating the amount of Plastin3 (Pls3), a previously unrecognized player of neural migration. Furthermore, we found that Pls3 cell-autonomously regulates cell migration by regulating actin cytoskeleton organization, and its levels are inversely proportional to neural migration speed. Finally, we provide evidence that cellular phenotypes associated with autism-linked gene haploinsufficiency can be rescued by transcriptional activation of the intact allele in vitro, offering a proof of concept for a potential therapeutic approach for ASDs.

scholarly journals Variants in PRKAR1B cause a neurodevelopmental disorder with autism spectrum disorder, apraxia, and insensitivity to pain

2021 ◽  
Author(s):  
Felix Marbach ◽  
◽  
Georgi Stoyanov ◽  
Florian Erger ◽  
Constantine A. Stratakis ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Global Developmental Delay ◽  
Missense Variants ◽  
Large Patient ◽  
Significant Enrichment

Abstract Purpose We characterize the clinical and molecular phenotypes of six unrelated individuals with intellectual disability and autism spectrum disorder who carry heterozygous missense variants of the PRKAR1B gene, which encodes the R1β subunit of the cyclic AMP-dependent protein kinase A (PKA). Methods Variants of PRKAR1B were identified by single- or trio-exome analysis. We contacted the families and physicians of the six individuals to collect phenotypic information, performed in vitro analyses of the identified PRKAR1B-variants, and investigated PRKAR1B expression during embryonic development. Results Recent studies of large patient cohorts with neurodevelopmental disorders found significant enrichment of de novo missense variants in PRKAR1B. In our cohort, de novo origin of the PRKAR1B variants could be confirmed in five of six individuals, and four carried the same heterozygous de novo variant c.1003C>T (p.Arg335Trp; NM_001164760). Global developmental delay, autism spectrum disorder, and apraxia/dyspraxia have been reported in all six, and reduced pain sensitivity was found in three individuals carrying the c.1003C>T variant. PRKAR1B expression in the brain was demonstrated during human embryonal development. Additionally, in vitro analyses revealed altered basal PKA activity in cells transfected with variant-harboring PRKAR1B expression constructs. Conclusion Our study provides strong evidence for a PRKAR1B-related neurodevelopmental disorder.

scholarly journals Overlapping central and peripheral nervous system syndromes in MOG antibody–associated disorders

2020 ◽  
Vol 8 (1) ◽  
pp. e924
Author(s):  
Simon Rinaldi ◽  
Alexander Davies ◽  
Janev Fehmi ◽  
Heidi N. Beadnall ◽  
Justine Wang ◽  
...  
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Transverse Myelitis ◽  
Multifocal Motor Neuropathy ◽  
Cortical Lesion ◽  
Motor Neuropathy ◽  
Cell Surface Antigens ◽  
Coculture Model ◽  
Clinical Phenotyping

ObjectiveAntibodies to myelin oligodendrocyte glycoprotein (MOG) are associated with CNS demyelination inclusive of optic neuritis (ON) and transverse myelitis (TM). To examine whether peripheral nervous system (PNS) involvement is associated with MOG antibody–associated disorders (MOGAD), we performed detailed characterization of an Australasian MOGAD cohort.MethodsUsing a live cell–based assay, we diagnosed 271 adults with MOGAD (2013–2018) and performed detailed clinical and immunologic characterization on those with likely PNS involvement.ResultsWe identified 19 adults with MOGAD and PNS involvement without prior TM. All patients had CNS involvement including ON (bilateral [n = 3], unilateral [n = 3], and recurrent [n = 7]), a cortical lesion (n = 1), meningoencephalitis (n = 1), and subsequent TM (n = 4). Clinical phenotyping and neurophysiology were consistent with acute inflammatory demyelinating polyneuropathy (n = 1), myeloradiculitis (n = 3), multifocal motor neuropathy (n = 1), brachial neuritis (n = 2), migrant sensory neuritis (n = 3), and paresthesia and/or radicular limb pain (n = 10). Onset MRI spine was consistent with myeloradiculitis with nerve root enhancement in 3/19 and normal in 16/19. Immunotherapy resulted in partial/complete PNS symptom resolution in 12/15 (80%) (steroids and/or IV immunoglobulin n = 9, rituximab n = 2, and plasmapheresis n = 1). We identified serum antibodies targeting neurofascin 155, contactin-associated protein 2, or GM1 in 4/16 patients with MOGAD PNS compared with 0/30 controls (p = 0.01). There was no binding to novel cell surface antigens using an in vitro myelinating sensory neuronal coculture model.ConclusionsMyeloradiculitis, combined central and peripheral demyelination syndromes, and inflammatory neuropathies may be associated with MOGAD and may be immunotherapy responsive. We identified a subgroup who may have pathology mediated by coexistent autoantibodies.

scholarly journals CHD8 Regulates Cellular Homeostasis and Neuronal Function Genes Across Multiple Models of CHD8 Haploinsufficiency

2018 ◽  
Author(s):  
A. Ayanna Wade ◽  
Kenneth Lim ◽  
Rinaldo Catta-Preta ◽  
Alex S. Nord
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Chromatin Remodeling ◽  
De Novo ◽  
Autism Spectrum ◽  
Loss Of Function ◽  
Cell Functions ◽  
High Affinity

ABSTRACTThe packaging of DNA into chromatin determines the transcriptional potential of cells and is central to eukaryotic gene regulation. Recent sequencing of patient mutations has linked de novo loss-of-function mutations to chromatin remodeling factors with specific, causal roles in neurodevelopmental disorders. Characterizing cellular and molecular phenotypes arising from haploinsufficiency of chromatin remodeling factors could reveal convergent mechanisms of pathology. Chromodomain helicase DNA binding protein 8 (CHD8) encodes a chromatin remodeling factor gene and has among the highest de novo loss-of-function mutations rates in patients with autism spectrum disorder (ASD). Mutations to CHD8 are expected to drive neurodevelopmental pathology through global disruptions to gene expression and chromatin state, however, mechanisms associated with CHD8 function have yet to be fully elucidated. We analyzed published transcriptomic and epigenomic data across CHD8 in vitro and in vivo knockdown and knockout models to identify convergent mechanisms of gene regulation by CHD8. We found reproducible high-affinity interactions of CHD8 near promoters of genes necessary for basic cell functions and gene regulation, especially chromatin organization and RNA processing genes. Overlap between CHD8 interaction and differential expression suggests that reduced dosage of CHD8 directly relates to decreased expression of these genes. In addition, genes important for neuronal development and function showed consistent dysregulation, though there was a reduced rate and decreased affinity for CHD8 interactions near these genes. This meta-analysis verifies CHD8 as a critical regulator of gene expression and reveals a consistent set of high affinity CHD8 interaction targets observed across human and mouse in vivo and in vitro studies. Our findings highlight novel core functions of CHD8 and indicate direct and downstream gene regulatory impacts that are likely to be associated with neuropathology underlying CHD8-associated neurodevelopmental disorder.

scholarly journals Germline nuclear-predominant Pten murine model exhibits impaired social and perseverative behavior, microglial activation, and increased oxytocinergic activity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nick Sarn ◽  
Stetson Thacker ◽  
Hyunpil Lee ◽  
Charis Eng
Keyword(s):  
Social Behavior ◽  
Microglial Activation ◽  
Repetitive Behavior ◽  
Suppressor Gene ◽  
Autism Spectrum ◽  
Animal Modeling ◽  
Therapeutic Modalities ◽  
Downstream Effects

Abstract Background Autism spectrum disorder (ASD) has a strong genetic etiology. Germline mutation in the tumor suppressor gene PTEN is one of the best described monogenic risk cases for ASD. Animal modeling of cell-specific Pten loss or mutation has provided insight into how disruptions to the function of PTEN affect neurodevelopment, neurobiology, and social behavior. As such, there is a growing need to understand more about how various aspects of PTEN activity and cell-compartment-specific functions, contribute to certain neurological or behavior phenotypes. Methods To understand more about the relationship between Pten localization and downstream effects on neurophenotypes, we generated the nuclear-predominant PtenY68H/+ mouse, which is identical to the genotype of some PTEN-ASD individuals. We subjected the PtenY68H/+ mouse to morphological and behavioral phenotyping, including the three-chamber sociability, open field, rotarod, and marble burying tests. We subsequently performed in vivo and in vitro cellular phenotyping and concluded the work with a transcriptomic survey of the PtenY68H/+ cortex, which profiled gene expression. Results We observe a significant increase in P-Akt downstream of canonical Pten signaling, macrocephaly, decreased sociability, decreased preference for novel social stimuli, increased repetitive behavior, and increased thigmotaxis in PtenY68H/+ six-week-old (P40) mice. In addition, we found significant microglial activation with increased expression of complement and neuroinflammatory proteins in vivo and in vitro accompanied by enhanced phagocytosis. These observations were subsequently validated with RNA-seq and qRT-PCR, which revealed overexpression of many genes involved in neuroinflammation and neuronal function, including oxytocin. Oxytocin transcript was fivefold overexpressed (P = 0.0018), and oxytocin protein was strongly overexpressed in the PtenY68H/+ hypothalamus. Conclusions The nuclear-predominant PtenY68H/+ model has clarified that Pten dysfunction links to microglial pathology and this associates with increased Akt signaling. We also demonstrate that Pten dysfunction associates with changes in the oxytocin system, an important connection between a prominent ASD risk gene and a potent neuroendocrine regulator of social behavior. These cellular and molecular pathologies may related to the observed changes in social behavior. Ultimately, the findings from this work may reveal important biomarkers and/or novel therapeutic modalities that could be explored in individuals with germline mutations in PTEN with ASD.

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