scholarly journals A de novo missense mutation in TUBA1A results in reduced neural progenitor survival and differentiation

2017 ◽  
Author(s):  
Ashley M. Driver ◽  
Amy L. Pitstick ◽  
Chris N. Mayhew ◽  
Beth Kline-Fath ◽  
Howard M. Saal ◽  
...  
Keyword(s):  
Missense Mutation ◽  
De Novo ◽  
Neural Progenitor ◽  
New Mutation ◽  
Tubulin Genes ◽  
Cortical Dysgenesis ◽  
Brain Malformations ◽  
Summary Statement ◽  
Underlying Mechanisms ◽  
Induced Pluripotent

ABSTRACTMutations in tubulins have been implicated in numerous human neurobiological disorders collectively known as “tubulinopathies.” We identified a patient with severe cortical dysgenesis and a novel de novo heterozygous missense mutation in Tubulin Alpha 1a (TUBA1A, c.1225 G>T). Induced pluripotent stem cells derived from this individual were differentiated into two dimensional neural rosette clusters to identify underlying mechanisms for the severe cortical dysgenesis phenotype. Patient-derived clones showed evidence of impaired neural progenitor survival and differentiation with abnormal neural rosette formation, increases in cell death, and fewer post-mitotic neurons. These features correlate with the drastically underdeveloped cortical tissues seen in the proband. This is the first experimental evidence in human tissue suggesting a mechanism underlying the role for TUBA1A in cortical development.SUMMARY STATEMENTVariants in tubulin genes often lead to severe congenital brain malformations. Here we identify a new mutation in TUBA1A and use iPSCS to show this alters proliferation, differentiation and survival of neural progenitors.

scholarly journals De Novo Partial 13q22-q34 Trisomy with Typical Neurological and Immunological Findings: A Case Report with New Genetic Insights

2020 ◽  
Vol 11 (1) ◽  
pp. 21
Author(s):  
Claudia Brogna ◽  
Valentina Milano ◽  
Barbara Brogna ◽  
Lara Cristiano ◽  
Giuseppe Rovere ◽  
...  
Keyword(s):  
Case Report ◽  
De Novo ◽  
Partial Trisomy ◽  
Cerebral Vasculitis ◽  
Radiological Findings ◽  
Cerebral Lesions ◽  
Brain Malformations ◽  
Vermian Hypoplasia ◽  
Callosal Dysgenesis ◽  
First Time

The partial trisomy 13q encompasses an extensive variability of phenotypic and radiological findings including leukoencephalopathy and brain malformations such as holoprosencephaly, callosal dysgenesis, hippocampal hypoplasia, olfactory hypoplasia, and vermian hypoplasia. We report for the first time a case of a 23-year-old patient affected by de novo partial 13q22.1q34 trisomy (41.7 Mb, 72,365,975-114,077,122x3) presenting with hemiparesis related to both ischemic and haemorrhagic cerebral lesions compatible with cerebral vasculitis due to a possible combination of genetic and immunological interaction.

A De Novo Dominant Negative Mutation in DNM1L Causes Sudden Onset Status Epilepticus with Subsequent Epileptic Encephalopathy

2019 ◽  
Vol 50 (03) ◽  
pp. 197-201
Author(s):  
S. Schmid ◽  
M. Wagner ◽  
C. Goetz ◽  
C. Makowski ◽  
P. Freisinger ◽  
...  
Keyword(s):  
Status Epilepticus ◽  
Missense Mutation ◽  
De Novo ◽  
Mitochondrial Fission ◽  
Refractory Status Epilepticus ◽  
Sudden Onset ◽  
Epileptic Encephalopathy ◽  
Neurologic Outcome ◽  
Dominant Negative Mutation ◽  
Refractory Status

AbstractMitochondrial dynamics such as fission and fusion play a vital role in normal brain development and neuronal activity. DNM1L encodes a dynamin-related protein 1 (Drp1), which is a GTPase essential for proper mitochondrial fission. The clinical phenotype of DNM1L mutations depends on the degree of mitochondrial fission deficiency, ranging from severe encephalopathy and death shortly after birth to initially normal development and then sudden onset of refractory status epilepticus with very poor neurologic outcome. We describe a case of a previously healthy 3-year-old boy with a mild delay in speech development until the acute onset of a refractory status epilepticus with subsequent epileptic encephalopathy and very poor neurologic outcome. The de novo missense mutation in DNM1L (c.1207C > T, p.R403C), which we identified in this case, seems to determine a unique clinical course, strikingly similar to four previously described patients in literature with the identical de novo heterozygous missense mutation in DNM1L.

scholarly journals Dual modulation of Ras-Mnk and PI3K-AKT-mTOR pathways: A Novel c-FLIP inhibitory mechanism of 3-AWA mediated translational attenuation through dephosphorylation of eIF4E

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Reyaz ur Rasool ◽  
Bilal Rah ◽  
Hina Amin ◽  
Debasis Nayak ◽  
Souneek Chakraborty ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Cell Cycle Progression ◽  
De Novo ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Apoptosis Resistance ◽  
Nih3t3 Cells ◽  
Eukaryotic Translation ◽  
Underlying Mechanisms

Abstract The eukaryotic translation initiation factor 4E (eIF4E) is considered as a key survival protein involved in cell cycle progression, transformation and apoptosis resistance. Herein, we demonstrate that medicinal plant derivative 3-AWA (from Withaferin A) suppressed the proliferation and metastasis of CaP cells through abrogation of eIF4E activation and expression via c-FLIP dependent mechanism. This translational attenuation prevents the de novo synthesis of major players of metastatic cascades viz. c-FLIP, c-Myc and cyclin D1. Moreover, the suppression of c-FLIP due to inhibition of translation initiation complex by 3-AWA enhanced FAS trafficking, BID and caspase 8 cleavage. Further ectopically restored c-Myc and GFP-HRas mediated activation of eIF4E was reduced by 3-AWA in transformed NIH3T3 cells. Detailed underlying mechanisms revealed that 3-AWA inhibited Ras-Mnk and PI3-AKT-mTOR, two major pathways through which eIF4E converges upon eIF4F hub. In addition to in vitro studies, we confirmed that 3-AWA efficiently suppressed tumor growth and metastasis in different mouse models. Given that 3-AWA inhibits c-FLIP through abrogation of translation initiation by co-targeting mTOR and Mnk-eIF4E, it (3-AWA) can be exploited as a lead pharmacophore for promising anti-cancer therapeutic development.

Identification of two novel de novo TUBB variants in cases with brain malformations: case reports and literature review

2021 ◽  
Author(s):  
Kazuki Watanabe ◽  
Mitsuko Nakashima ◽  
Satoko Kumada ◽  
Hideaki Mashimo ◽  
Mikako Enokizono ◽  
...  
Keyword(s):  
Literature Review ◽  
De Novo ◽  
Case Reports ◽  
Brain Malformations

scholarly journals Gene-specific mechanisms direct glucocorticoid-receptor-driven repression of inflammatory response genes in macrophages

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Maria A Sacta ◽  
Bowranigan Tharmalingam ◽  
Maddalena Coppo ◽  
David A Rollins ◽  
Dinesh K Deochand ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Binding Sites ◽  
De Novo ◽  
Elongation Factor ◽  
Myeloid Cell ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
Mouse Macrophages ◽  
Underlying Mechanisms ◽  
Temporal Events

The glucocorticoid receptor (GR) potently represses macrophage-elicited inflammation, however, the underlying mechanisms remain obscure. Our genome-wide analysis in mouse macrophages reveals that pro-inflammatory paused genes, activated via global negative elongation factor (NELF) dissociation and RNA Polymerase (Pol)2 release from early elongation arrest, and non-paused genes, induced by de novo Pol2 recruitment, are equally susceptible to acute glucocorticoid repression. Moreover, in both cases the dominant mechanism involves rapid GR tethering to p65 at NF-kB-binding sites. Yet, specifically at paused genes, GR activation triggers widespread promoter accumulation of NELF, with myeloid cell-specific NELF deletion conferring glucocorticoid resistance. Conversely, at non-paused genes, GR attenuates the recruitment of p300 and histone acetylation, leading to a failure to assemble BRD4 and Mediator at promoters and enhancers, ultimately blocking Pol2 initiation. Thus, GR displays no preference for a specific pro-inflammatory gene class; however, it effects repression by targeting distinct temporal events and components of transcriptional machinery.

scholarly journals Neural Progenitor Cells Undergoing Yap/Tead-Mediated Enhanced Self-Renewal Form Heterotopias More Easily in the Diencephalon than in the Telencephalon

2018 ◽  
Vol 43 (1) ◽  
pp. 180-189 ◽  
Author(s):  
Kanako Saito ◽  
Ryotaro Kawasoe ◽  
Hiroshi Sasaki ◽  
Ayano Kawaguchi ◽  
Takaki Miyata
Keyword(s):  
Progenitor Cells ◽  
Neural Tube ◽  
Neural Progenitor Cells ◽  
Three Dimensional ◽  
Neural Progenitor ◽  
Hippo Signaling ◽  
Apical Surface ◽  
Elevated Expression ◽  
Underlying Mechanisms ◽  
The Brain

Abstract Spatiotemporally ordered production of cells is essential for brain development. Normally, most undifferentiated neural progenitor cells (NPCs) face the apical (ventricular) surface of embryonic brain walls. Pathological detachment of NPCs from the apical surface and their invasion of outer neuronal territories, i.e., formation of NPC heterotopias, can disrupt the overall structure of the brain. Although NPC heterotopias have previously been observed in a variety of experimental contexts, the underlying mechanisms remain largely unknown. Yes-associated protein 1 (Yap1) and the TEA domain (Tead) proteins, which act downstream of Hippo signaling, enhance the stem-like characteristics of NPCs. Elevated expression of Yap1 or Tead in the neural tube (future spinal cord) induces massive NPC heterotopias, but Yap/Tead-induced expansion of NPCs in the developing brain has not been previously reported to produce NPC heterotopias. To determine whether NPC heterotopias occur in a regionally characteristic manner, we introduced the Yap1-S112A or Tead-VP16 into NPCs of the telencephalon and diencephalon, two neighboring but distinct forebrain regions, of embryonic day 10 mice by in utero electroporation, and compared NPC heterotopia formation. Although NPCs in both regions exhibited enhanced stem-like behaviors, heterotopias were larger and more frequent in the diencephalon than in the telencephalon. This result, the first example of Yap/Tead-induced NPC heterotopia in the forebrain, reveals that Yap/Tead-induced NPC heterotopia is not specific to the neural tube, and also suggests that this phenomenon depends on regional factors such as the three-dimensional geometry and assembly of these cells.

scholarly journals TUBA1A mutations identified in lissencephaly patients dominantly disrupt neuronal migration and impair dynein activity

2018 ◽  
Vol 28 (8) ◽  
pp. 1227-1243 ◽  
Author(s):  
Jayne Aiken ◽  
Jeffrey K Moore ◽  
Emily A Bates
Keyword(s):  
Motor Activity ◽  
Neuronal Migration ◽  
Ectopic Expression ◽  
Missense Mutations ◽  
Microtubule Cytoskeleton ◽  
Tubulin Genes ◽  
Dynein Motor ◽  
Brain Malformations ◽  
Developing Mouse Brain ◽  
And Migration

Abstract The microtubule cytoskeleton supports diverse cellular morphogenesis and migration processes during brain development. Mutations in tubulin genes are associated with severe human brain malformations known as ‘tubulinopathies’; however, it is not understood how molecular-level changes in microtubule subunits lead to brain malformations. In this study, we demonstrate that missense mutations affecting arginine at position 402 (R402) of TUBA1A α-tubulin selectively impair dynein motor activity and severely and dominantly disrupt cortical neuronal migration. TUBA1A is the most commonly affected tubulin gene in tubulinopathy patients, and mutations altering R402 account for 30% of all reported TUBA1A mutations. We show for the first time that ectopic expression of TUBA1A-R402C and TUBA1A-R402H patient alleles is sufficient to dominantly disrupt cortical neuronal migration in the developing mouse brain, strongly supporting a causal role in the pathology of brain malformation. To isolate the precise molecular impact of R402 mutations, we generated analogous R402C and R402H mutations in budding yeast α-tubulin, which exhibit a simplified microtubule cytoskeleton. We find that R402 mutant tubulins assemble into microtubules that support normal kinesin motor activity but fail to support the activity of dynein motors. Importantly, the level of dynein impairment scales with the expression level of the mutant in the cell, suggesting a ‘poisoning’ mechanism in which R402 mutant α-tubulin acts dominantly by populating microtubules with defective binding sites for dynein. Based on our results, we propose a new model for the molecular pathology of tubulinopathies that may also extend to other tubulin-related neuropathies.

scholarly journals PRMT7: A Pivotal Arginine Methyltransferase in Stem Cells and Development

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Bingyuan Wang ◽  
Mingrui Zhang ◽  
Zhiguo Liu ◽  
Yulian Mu ◽  
Kui Li
Keyword(s):  
Stem Cells ◽  
Developmental Delay ◽  
Molecular Mechanisms ◽  
Human Cancer ◽  
Embryonic Stem ◽  
Arginine Methylation ◽  
Male Reproduction ◽  
Protein Arginine Methyltransferases ◽  
Underlying Mechanisms ◽  
Induced Pluripotent

Protein arginine methylation is a posttranslational modification catalyzed by protein arginine methyltransferases (PRMTs), which play critical roles in many biological processes. To date, nine PRMT family members, namely, PRMT1, 2, 3, 4, 5, 6, 7, 8, and 9, have been identified in mammals. Among them, PRMT7 is a type III PRMT that can only catalyze the formation of monomethylarginine and plays pivotal roles in several kinds of stem cells. It has been reported that PRMT7 is closely associated with embryonic stem cells, induced pluripotent stem cells, muscle stem cells, and human cancer stem cells. PRMT7 deficiency or mutation led to severe developmental delay in mice and humans, which is possibly due to its crucial functions in stem cells. Here, we surveyed and summarized the studies on PRMT7 in stem cells and development in mice and humans and herein provide a discussion of the underlying molecular mechanisms. Furthermore, we also discuss the roles of PRMT7 in cancer, adipogenesis, male reproduction, cellular stress, and cellular senescence, as well as the future perspectives of PRMT7-related studies. Overall, PRMT7 mediates the proliferation and differentiation of stem cells. Deficiency or mutation of PRMT7 causes developmental delay, including defects in skeletal muscle, bone, adipose tissues, neuron, and male reproduction. A better understanding of the roles of PRMT7 in stem cells and development as well as the underlying mechanisms will provide information for the development of strategies for in-depth research of PRMT7 and stem cells as well as their applications in life sciences and medicine.

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