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In JoVE (1)
Other Publications (9)
- The Journal of Neuroscience : the Official Journal of the Society for Neuroscience
- Molecular and Cellular Neurosciences
- American Journal of Medical Genetics. Part A
- Human Mutation
- European Journal of Paediatric Neurology : EJPN : Official Journal of the European Paediatric Neurology Society
- Annals of Neurology
- Current Opinion in Genetics & Development
- PLoS Genetics
- BMC Research Notes
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Articles by M. Chiara Manzini in JoVE
JoVE General
Выделение и культуры послеродовой мыши мозжечка гранул клеток-предшественников нейронов и нейронов
1Department of Genetics and Development, Columbia University, 2Department of Pathology and Cell Biology, Columbia University, 3Department of Neuroscience, Columbia University, 4Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School
Здесь мы представляем метод, чтобы изолировать и культуры мозжечка гранул нейронных клеток-предшественников нейронов мозжечка и гранулы из послеродового мыши.
Other articles by M. Chiara Manzini on PubMed
The Stop Signal Revised: Immature Cerebellar Granule Neurons in the External Germinal Layer Arrest Pontine Mossy Fiber Growth
During the formation of neuronal circuits, afferent axons often enter target regions before their target cells are mature and then make temporary contacts with nonspecific targets before forming synapses on specific target cells. The regulation of these different steps of afferent-target interactions is poorly understood. The cerebellum is a good model for addressing these aspects, because cerebellar development is well defined and identified neurons in the circuitry can be purified and combined in vitro. Previous reports from our laboratory showed that cultured granule neurons specifically arrest the extension of their pontine mossy fiber afferents, leading us to propose that granule cells arrested growth of their afferents as a prelude to synaptogenesis. However, we knew little about the differentiation state of the cultured granule cells that mediate afferent arrest. In this study, we better define the purified granule cell fraction by marker expression and morphology, and demonstrate that only freshly plated granule cells in the precursor and premigratory state arrest mossy fiber outgrowth. Mature granule cells, in contrast, support extension, defasciculation, and synapse formation, as in vivo. In addition, axonal tracing in vivo during the first postnatal week indicates that immature mossy fibers extend into the Purkinje cell layer but never into the external germinal layer (EGL), where precursors of granule cell targets reside. We found that the stop-growing signals are dependent on heparin-binding factors, and we propose that such signals in the EGL restrict the extension of mossy fiber afferents and prevent invasion of proliferative regions.
Differential Effects of AMPA Receptor Activation on Survival and Neurite Integrity During Neuronal Development
While neuronal cultures are an established model for analyzing excitotoxic brain injury in the adult, in vitro systems have not been extensively employed to study how developing neurons respond to levels of excitatory compounds that are lethal to mature neurons. Recently, we reported that the in vivo differentiation programs of cerebellar granule cells (CGNs) are recapitulated in purified CGN cultures [Manzini M.C., Ward M.S., Zhang Q., Lieberman M.D., Mason C.A. (2006) The stop-signal revised: immature cerebellar granule neurons in the external germinal layer arrest pontine mossy fiber growth. J. Neurosci. 26:6040-6051]. Here, we have used this model system to compare the response of immature and mature neurons to excitotoxic compounds. We found that immature CGNs are less sensitive to AMPA receptor (AMPA-R) activation than mature cells and that levels of AMPA-R expression on the plasma membrane are critical in regulating the balance between death and survival during maturation of these neurons. However, the majority of immature cells that survive excitotoxic treatment bear a degenerating neurite, suggesting that AMPA-R activation can still cause damage in the absence of cell death.
A Novel Form of Lethal Microcephaly with Simplified Gyral Pattern and Brain Stem Hypoplasia
We report on four patients from the same family affected by a lethal form of autosomal recessive microcephaly of prenatal onset. Symptoms include low birth-weight and length with disproportionately small head, fetal distress, apnea, seizures and facial features reminiscent of Amish microcephaly and Bowen-Conradi syndrome. Brain imaging revealed a simplified gyral pattern with normal to slightly thinned cortical gray matter, thin corpus callosum, mild brainstem and cerebellar hypoplasia. No abnormalities of the internal organs, eye, or skeleton, and no striking dysmorphic facial features were found to be associated with this syndrome. All patients died within hours to weeks after birth following severe apnea attacks and central hypoventilation. Recessive primary microcephaly with lethality in early infancy is rarely reported. The patients described here do not resemble any other published cases of such clinical severity and the locus for the only reported early lethal microcephaly gene found in Amish families was excluded. Therefore, this appears to be a distinct genetic cause of lethal microcephaly.
Ethnically Diverse Causes of Walker-Warburg Syndrome (WWS): FCMD Mutations Are a More Common Cause of WWS Outside of the Middle East
Walker-Warburg syndrome (WWS) is a genetically heterogeneous autosomal recessive disease characterized by congenital muscular dystrophy, cobblestone lissencephaly, and ocular malformations. Mutations in six genes involved in the glycosylation of á-dystroglycan (POMT1, POMT2, POMGNT1, FCMD, FKRP and LARGE) have been identified in WWS patients, but account for only a portion of WWS cases. To better understand the genetics of WWS and establish the frequency and distribution of mutations across WWS genes, we genotyped all known loci in a cohort of 43 WWS patients of varying geographical and ethnic origin. Surprisingly, we reached a molecular diagnosis for 40% of our patients and found mutations in POMT1, POMT2, FCMD and FKRP, many of which were novel alleles, but no mutations in POMGNT1 or LARGE. Notably, the FCMD gene was a more common cause of WWS than previously expected in the European/American subset of our cohort, including all Ashkenazi Jewish cases, who carried the same founder mutation.
Severe Muscle-eye-brain Disease is Associated with a Homozygous Mutation in the POMGnT1 Gene
Muscle-eye-brain (MEB) disease is an autosomal recessive disorder characterized by a broad clinical spectrum including congenital muscular dystrophy, ocular abnormalities, and brain malformation (type-II lissencephaly). Herein, we report on two Turkish siblings with a homozygous mutation in the POMGnT1 gene. A 6-year-old sibling has a severe form of MEB disease, which in some aspects is more suitable with the diagnosis of Walker-Warburg syndrome. However, the same mutation resulted in a less severe form of MEB in the older sibling, who is 14 years old. These two cases suggest that POMGnT1 mutations may cause MEB disease with different phenotypes even in the same family.
Developmental and Degenerative Features in a Complicated Spastic Paraplegia
We sought to explore the genetic and molecular causes of Troyer syndrome, one of several complicated hereditary spastic paraplegias (HSPs). Troyer syndrome had been thought to be restricted to the Amish; however, we identified 2 Omani families with HSP, short stature, dysarthria and developmental delay-core features of Troyer syndrome-and a novel mutation in the SPG20 gene, which is also mutated in the Amish. In addition, we analyzed SPG20 expression throughout development to infer how disruption of this gene might generate the constellation of developmental and degenerative Troyer syndrome phenotypes.
What Disorders of Cortical Development Tell Us About the Cortex: One Plus One Does Not Always Make Two
The unique size and complexity of the human cerebral cortex are achieved via a long and precisely regulated developmental process controlling neurogenesis, neuronal migration and differentiation. Traditionally, disorders of cortical development have been classified on the basis of the most obvious defects in one of these developmental steps. However, the more we learn about the cellular biological roles of genes that are essential for cortical development, the more we realize that these functions map onto molecular processes, but not so cleanly onto anatomical processes. Essential genes might be involved in both proliferation and migration as well as differentiation, reflecting roles for underlying molecular mechanisms in different phases of development and causing a stunning variety of cortical defects.
COL4A1 Mutations Cause Ocular Dysgenesis, Neuronal Localization Defects, and Myopathy in Mice and Walker-Warburg Syndrome in Humans
Muscle-eye-brain disease (MEB) and Walker Warburg Syndrome (WWS) belong to a spectrum of autosomal recessive diseases characterized by ocular dysgenesis, neuronal migration defects, and congenital muscular dystrophy. Until now, the pathophysiology of MEB/WWS has been attributed to alteration in dystroglycan post-translational modification. Here, we provide evidence that mutations in a gene coding for a major basement membrane protein, collagen IV alpha 1 (COL4A1), are a novel cause of MEB/WWS. Using a combination of histological, molecular, and biochemical approaches, we show that heterozygous Col4a1 mutant mice have ocular dysgenesis, neuronal localization defects, and myopathy characteristic of MEB/WWS. Importantly, we identified putative heterozygous mutations in COL4A1 in two MEB/WWS patients. Both mutations occur within conserved amino acids of the triple-helix-forming domain of the protein, and at least one mutation interferes with secretion of the mutant proteins, resulting instead in intracellular accumulation. Expression and posttranslational modification of dystroglycan is unaltered in Col4a1 mutant mice indicating that COL4A1 mutations represent a distinct pathogenic mechanism underlying MEB/WWS. These findings implicate a novel gene and a novel mechanism in the etiology of MEB/WWS and expand the clinical spectrum of COL4A1-associated disorders.
