Melitta Schachner - Academia.edu (original) (raw)

Papers by Melitta Schachner

The Journal of Neuroscience, 2001

Cerebral cortex (New York, N.Y. : 1991), Feb 5, 2016

The generation of layer-specific neurons and astrocytes by radial glial cells during development ... more The generation of layer-specific neurons and astrocytes by radial glial cells during development of the cerebral cortex follows a precise temporal sequence, which is regulated by intrinsic and extrinsic factors. The molecular mechanisms controlling the timely generation of layer-specific neurons and astrocytes remain not fully understood. In this study, we show that the adhesion molecule contactin-associated protein (Caspr), which is involved in the maintenance of the polarized domains of myelinated axons, is essential for the timing of generation of neurons and astrocytes in the developing mouse cerebral cortex. Caspr is expressed by radial glial cells, which are neural progenitor cells that generate both neurons and astrocytes. Absence of Caspr in neural progenitor cells delays the production cortical neurons and induces precocious formation of cortical astrocytes, without affecting the numbers of progenitor cells. At the molecular level, Caspr cooperates with the intracellular do...

Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, Jan 11, 2015

Disrupted-in-schizophrenia-1 (DISC1) is a genetic risk factor for a wide range of major mental di... more Disrupted-in-schizophrenia-1 (DISC1) is a genetic risk factor for a wide range of major mental disorders including schizophrenia, major depression and bipolar disorders. Recent reports suggest a potential role of DISC1 in the pathogenesis of Alzheimer's disease (AD), by referring to an interaction between DISC1 and amyloid precursor protein (APP), and to an association of a single nucleotide polymorphism in a DISC1 intron and late onset of AD. However, the function of DISC1 in AD remains unknown. In this study, decreased levels of DISC1 were observed in the cortex and hippocampus of 8-month-old APP/PS1 transgenic mice, an animal model of AD. Overexpression of DISC1 reduced, while knockdown of DISC1 increased protein levels, but not mRNA levels of β-site APP-Cleaving Enzyme 1 (BACE1), a key enzyme in amyloid-β (Aβ) generation. Reduction of BACE1 protein levels by overexpression of DISC1 was accompanied by an accelerating decline rate of BACE1, and was blocked by the lysosomal inh...

Nature Cell Biology, 2008

Journal of Biological Chemistry, 2004

BMC Molecular Biology, 2009

Background The neural cell adhesion molecule L1 plays a crucial role in development and plasticit... more Background The neural cell adhesion molecule L1 plays a crucial role in development and plasticity of the nervous system. Neural cells thus require precise control of L1 expression. Results We identified a full binding site for nuclear factor I (NFI) transcription factors in the regulatory region of the mouse L1 gene. Electrophoretic mobility shift assay (EMSA) showed binding of nuclear factor I-A (NFI-A) to this site. Moreover, for a brain-specific isoform of NFI-A (NFI-A bs), we confirmed the interaction in vivo using chromatin immunoprecipitation (ChIP). Reporter gene assays showed that in neuroblastoma cells, overexpression of NFI-A bs repressed L1 expression threefold. Conclusion Our findings suggest that NFI-A, in particular its brain-specific isoform, represses L1 gene expression, and might act as a second silencer of L1 in addition to the neural restrictive silencer factor (NRSF).

STUDY DESIGNAnimal studyOBJECTIVESFemale mice deficient in the adhesion molecule CHL1 recovered b... more STUDY DESIGNAnimal studyOBJECTIVESFemale mice deficient in the adhesion molecule CHL1 recovered better than their wild-type female littermates after spinal cord injury (SCI). This observation was unexpected, because CHL1 increases neurite outgrowth in vitro in a homophilic, neuron-dependent manner. Yet, in SCI, CHL1 is upregulated in the glial scar which reduces axonal regrowth, showing that CHL1 on glia can block regrowth of CHL1 positive axons. This notion that was verified in co-cultures of astrocytes and neurons. Since these SCI experiments were confined to females in the previous study, we now sought to assess SCI in CHL1-deficient male mice.SETTINGSW.M. Keck Center for Collaborative Neuroscience at RutgersMETHODSMale CHL1-deficient and wild-type littermate mice received thoracic weight-drop SCI. Locomotor recovery was analyzed weekly by the Basso Mouse Scale and a single frame motion analysis up to six weeks after SCI, when lesion volumes were measured immunohistologically. He...

International Journal of Molecular Sciences

Myristoylated alanine-rich C-kinase substrate (MARCKS) is a critical member of a signaling cascad... more Myristoylated alanine-rich C-kinase substrate (MARCKS) is a critical member of a signaling cascade that influences disease-relevant neural functions such as neural growth and plasticity. The effector domain (ED) of MARCKS interacts with the extracellular glycan polysialic acid (PSA) through the cell membrane to stimulate neurite outgrowth in cell culture. We have shown that a synthetic ED peptide improves functional recovery after spinal cord injury in female but not male mice. However, peptides themselves are unstable in therapeutic applications, so we investigated more pharmacologically relevant small organic compounds that mimic the ED peptide to maximize therapeutic potential. Using competition ELISAs, we screened small organic compound libraries to identify molecules that structurally and functionally mimic the ED peptide of MARCKS. Since we had shown sex-specific effects of MARCKS on spinal cord injury recovery, we assayed neuronal viability as well as neurite outgrowth from c...

International Journal of Molecular Sciences

Adhesion molecules regulate cell proliferation, migration, survival, neuritogenesis, synapse form... more Adhesion molecules regulate cell proliferation, migration, survival, neuritogenesis, synapse formation and synaptic plasticity during the nervous system’s development and in the adult. Among such molecules, the neural cell adhesion molecule L1 contributes to these functions during development, and in synapse formation, synaptic plasticity and regeneration after trauma. Proteolytic cleavage of L1 by different proteases is essential for these functions. A proteolytic fragment of 70 kDa (abbreviated L1-70) comprising part of the extracellular domain and the transmembrane and intracellular domains was shown to interact with mitochondrial proteins and is suggested to be involved in mitochondrial functions. To further determine the role of L1-70 in mitochondria, we generated two lines of gene-edited mice expressing full-length L1, but no or only low levels of L1-70. We showed that in the absence of L1-70, mitochondria in cultured cerebellar neurons move more retrogradely and exhibit reduc...

Deficiency in the extracellular matrix glycoprotein Reelin severely affects migration of neurons ... more Deficiency in the extracellular matrix glycoprotein Reelin severely affects migration of neurons during development. The function of serine at position 1283 in Reelin has remained uncertain. To explore its relevance we generated rlnA/A mice that carry alanine instead of serine at position 1283, thereby disrupting the putative casein kinase 2 (CK2) phosphorylation site S1283DGD. Mutated mice displayed reeler-like locomotor behavior, abnormal brain anatomy and decrease of Reelin RNA and protein levels during development and in adulthood. Since serine 1283 was previously proposed to mediate proteolysis of adhesion molecules, we investigated proteolysis of cell adhesion molecule L1 and found it normal in rlnA/A mice. Neuronal migration in the embryonic rlnA/A cerebral cortex was impaired, but rescued by in utero electroporation of the Reelin fragment N-R6 containing the putative CK2 phosphorylation site. In rlnA/A mice migration of cerebellar granule cells in vitro was promoted by appli...

The Journal of Neuroscience, 2003

The Journal of Neuroscience, 2002

BMC Cell Biology, 2002

BACKGROUND: Mutations in P0, the major protein of the myelin sheath in peripheral nerves, cause t... more BACKGROUND: Mutations in P0, the major protein of the myelin sheath in peripheral nerves, cause the inherited peripheral neuropathies Charcot-Marie-Tooth disease type 1B (CMT1B), Dejerine-Sottas syndrome (DSS) and congenital hypomyelination (CH). We reported earlier a de novo insertional mutation c.662_663GC (Ala221fs) in a DSS patient. The c.662_663GC insertion results in a frame shift mutation Ala221fs altering the C-terminal amino acid

Tissue Engineering Part A, 2013

The Journal of Neuroscience, 2011

The cysteine-rich protein (CRP) family is a subgroup of LIM domain proteins. CRP1, which cross-li... more The cysteine-rich protein (CRP) family is a subgroup of LIM domain proteins. CRP1, which cross-links actin filaments to make actin bundles, is the only CRP family member expressed in the CNS with little known about its function in nerve cells. Here, we report that CRP1 colocalizes with actin in the filopodia of growth cones in cultured rat hippocampal neurons. Knockdown of CRP1 expression by short hairpin RNA interference results in inhibition of filopodia formation and dendritic growth in neurons. Overexpression of CRP1 increases filopodia formation and neurite branching, which require its actin-bundling activity. Expression of CRP1 with a constitutively active form of Cdc42, a GTPase involved in filopodia formation, increases filopodia formation in COS-7 cells, suggesting cooperation between the two proteins. Moreover, we demonstrate that neuronal activity upregulates CRP1 expression in hippocampal neurons via Ca2+influx after depolarization. Ca2+/calmodulin-dependent protein kina...

The Journal of Neuroscience, 2008

Extensive neuronal cell death during development is believed to be due to a limiting supply of ne... more Extensive neuronal cell death during development is believed to be due to a limiting supply of neurotrophic factors.In vitrostudies suggest that axon guidance molecules directly regulate neuronal survival, raising the possibility that they play a direct role in neuronal cell deathin vivo. However, guidance errors may also influence survival indirectly due to loss of target-derived neurotrophic support. The role of guidance molecules in neuronal deathin vivohas thus been difficult to decipher. Semaphorin3A, a repulsive guidance cue for sensory neurons, can induce sensory neuron deathin vitro. Null mice studies of the Semaphorin3A coreceptors showed that guidance activity is mediated by PlexinA4, but PlexinA3 partially compensates in PlexinA4−/−mice. Here we demonstrate that both Plexins contribute to Sema3A-induced cell deathin vitro, albeit in a different hierarchy. PlexinA3 is absolutely required, while PlexinA4 makes a smaller contribution to cell death. We found that PlexinA3−/−m...

The Journal of cell biology, 1992

To gain insights into the functional role of the molecular association between neural adhesion mo... more To gain insights into the functional role of the molecular association between neural adhesion molecules and extracellular matrix constituents, soluble forms of the myelin-associated glycoprotein (MAG) and the neural cell adhesion molecule (N-CAM), representing most of the extracellular domains of the molecules, were investigated in their ability to modify fibrillogenesis of collagen type I. MAG and N-CAM retarded the rate of fibril formation, as measured by changes in turbidity, and increased the diameter of the fibrils formed, but did not change the banding pattern when compared to collagen type I in the absence of adhesion molecules. Scatchard plot analysis of the binding of MAG and N-CAM to the fibril-forming collagen types I, II, III, and V suggest one binding site for N-CAM and two binding sites for MAG. Binding of MAG, but not of N-CAM, to collagen type I was decreased during fibril formation, probably due to a reduced accessibility of one binding site for MAG during fibrillo...

Proceedings of the National Academy of Sciences, 2002

Myelin-associated glycoprotein (MAG) binds to the nerve cell surface and inhibits nerve regenerat... more Myelin-associated glycoprotein (MAG) binds to the nerve cell surface and inhibits nerve regeneration. The nerve cell surface ligand(s) for MAG are not established, although sialic acid-bearing glycans have been implicated. We identify the nerve cell surface gangliosides GD1a and GT1b as specific functional ligands for MAG-mediated inhibition of neurite outgrowth from primary rat cerebellar granule neurons. MAG-mediated neurite outgrowth inhibition is attenuated by ( i ) neuraminidase treatment of the neurons; ( ii ) blocking neuronal ganglioside biosynthesis; ( iii ) genetically modifying the terminal structures of nerve cell surface gangliosides; and ( iv ) adding highly specific IgG-class antiganglioside mAbs. Furthermore, neurite outgrowth inhibition is mimicked by highly multivalent clustering of GD1a or GT1b by using precomplexed antiganglioside Abs. These data implicate the nerve cell surface gangliosides GD1a and GT1b as functional MAG ligands and suggest that the first step ...

The Journal of Neuroscience, 2001

Cerebral cortex (New York, N.Y. : 1991), Feb 5, 2016

The generation of layer-specific neurons and astrocytes by radial glial cells during development ... more The generation of layer-specific neurons and astrocytes by radial glial cells during development of the cerebral cortex follows a precise temporal sequence, which is regulated by intrinsic and extrinsic factors. The molecular mechanisms controlling the timely generation of layer-specific neurons and astrocytes remain not fully understood. In this study, we show that the adhesion molecule contactin-associated protein (Caspr), which is involved in the maintenance of the polarized domains of myelinated axons, is essential for the timing of generation of neurons and astrocytes in the developing mouse cerebral cortex. Caspr is expressed by radial glial cells, which are neural progenitor cells that generate both neurons and astrocytes. Absence of Caspr in neural progenitor cells delays the production cortical neurons and induces precocious formation of cortical astrocytes, without affecting the numbers of progenitor cells. At the molecular level, Caspr cooperates with the intracellular do...

Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, Jan 11, 2015

Disrupted-in-schizophrenia-1 (DISC1) is a genetic risk factor for a wide range of major mental di... more Disrupted-in-schizophrenia-1 (DISC1) is a genetic risk factor for a wide range of major mental disorders including schizophrenia, major depression and bipolar disorders. Recent reports suggest a potential role of DISC1 in the pathogenesis of Alzheimer's disease (AD), by referring to an interaction between DISC1 and amyloid precursor protein (APP), and to an association of a single nucleotide polymorphism in a DISC1 intron and late onset of AD. However, the function of DISC1 in AD remains unknown. In this study, decreased levels of DISC1 were observed in the cortex and hippocampus of 8-month-old APP/PS1 transgenic mice, an animal model of AD. Overexpression of DISC1 reduced, while knockdown of DISC1 increased protein levels, but not mRNA levels of β-site APP-Cleaving Enzyme 1 (BACE1), a key enzyme in amyloid-β (Aβ) generation. Reduction of BACE1 protein levels by overexpression of DISC1 was accompanied by an accelerating decline rate of BACE1, and was blocked by the lysosomal inh...

Nature Cell Biology, 2008

Journal of Biological Chemistry, 2004

BMC Molecular Biology, 2009

Background The neural cell adhesion molecule L1 plays a crucial role in development and plasticit... more Background The neural cell adhesion molecule L1 plays a crucial role in development and plasticity of the nervous system. Neural cells thus require precise control of L1 expression. Results We identified a full binding site for nuclear factor I (NFI) transcription factors in the regulatory region of the mouse L1 gene. Electrophoretic mobility shift assay (EMSA) showed binding of nuclear factor I-A (NFI-A) to this site. Moreover, for a brain-specific isoform of NFI-A (NFI-A bs), we confirmed the interaction in vivo using chromatin immunoprecipitation (ChIP). Reporter gene assays showed that in neuroblastoma cells, overexpression of NFI-A bs repressed L1 expression threefold. Conclusion Our findings suggest that NFI-A, in particular its brain-specific isoform, represses L1 gene expression, and might act as a second silencer of L1 in addition to the neural restrictive silencer factor (NRSF).

STUDY DESIGNAnimal studyOBJECTIVESFemale mice deficient in the adhesion molecule CHL1 recovered b... more STUDY DESIGNAnimal studyOBJECTIVESFemale mice deficient in the adhesion molecule CHL1 recovered better than their wild-type female littermates after spinal cord injury (SCI). This observation was unexpected, because CHL1 increases neurite outgrowth in vitro in a homophilic, neuron-dependent manner. Yet, in SCI, CHL1 is upregulated in the glial scar which reduces axonal regrowth, showing that CHL1 on glia can block regrowth of CHL1 positive axons. This notion that was verified in co-cultures of astrocytes and neurons. Since these SCI experiments were confined to females in the previous study, we now sought to assess SCI in CHL1-deficient male mice.SETTINGSW.M. Keck Center for Collaborative Neuroscience at RutgersMETHODSMale CHL1-deficient and wild-type littermate mice received thoracic weight-drop SCI. Locomotor recovery was analyzed weekly by the Basso Mouse Scale and a single frame motion analysis up to six weeks after SCI, when lesion volumes were measured immunohistologically. He...

International Journal of Molecular Sciences

Myristoylated alanine-rich C-kinase substrate (MARCKS) is a critical member of a signaling cascad... more Myristoylated alanine-rich C-kinase substrate (MARCKS) is a critical member of a signaling cascade that influences disease-relevant neural functions such as neural growth and plasticity. The effector domain (ED) of MARCKS interacts with the extracellular glycan polysialic acid (PSA) through the cell membrane to stimulate neurite outgrowth in cell culture. We have shown that a synthetic ED peptide improves functional recovery after spinal cord injury in female but not male mice. However, peptides themselves are unstable in therapeutic applications, so we investigated more pharmacologically relevant small organic compounds that mimic the ED peptide to maximize therapeutic potential. Using competition ELISAs, we screened small organic compound libraries to identify molecules that structurally and functionally mimic the ED peptide of MARCKS. Since we had shown sex-specific effects of MARCKS on spinal cord injury recovery, we assayed neuronal viability as well as neurite outgrowth from c...

International Journal of Molecular Sciences

Adhesion molecules regulate cell proliferation, migration, survival, neuritogenesis, synapse form... more Adhesion molecules regulate cell proliferation, migration, survival, neuritogenesis, synapse formation and synaptic plasticity during the nervous system’s development and in the adult. Among such molecules, the neural cell adhesion molecule L1 contributes to these functions during development, and in synapse formation, synaptic plasticity and regeneration after trauma. Proteolytic cleavage of L1 by different proteases is essential for these functions. A proteolytic fragment of 70 kDa (abbreviated L1-70) comprising part of the extracellular domain and the transmembrane and intracellular domains was shown to interact with mitochondrial proteins and is suggested to be involved in mitochondrial functions. To further determine the role of L1-70 in mitochondria, we generated two lines of gene-edited mice expressing full-length L1, but no or only low levels of L1-70. We showed that in the absence of L1-70, mitochondria in cultured cerebellar neurons move more retrogradely and exhibit reduc...

Deficiency in the extracellular matrix glycoprotein Reelin severely affects migration of neurons ... more Deficiency in the extracellular matrix glycoprotein Reelin severely affects migration of neurons during development. The function of serine at position 1283 in Reelin has remained uncertain. To explore its relevance we generated rlnA/A mice that carry alanine instead of serine at position 1283, thereby disrupting the putative casein kinase 2 (CK2) phosphorylation site S1283DGD. Mutated mice displayed reeler-like locomotor behavior, abnormal brain anatomy and decrease of Reelin RNA and protein levels during development and in adulthood. Since serine 1283 was previously proposed to mediate proteolysis of adhesion molecules, we investigated proteolysis of cell adhesion molecule L1 and found it normal in rlnA/A mice. Neuronal migration in the embryonic rlnA/A cerebral cortex was impaired, but rescued by in utero electroporation of the Reelin fragment N-R6 containing the putative CK2 phosphorylation site. In rlnA/A mice migration of cerebellar granule cells in vitro was promoted by appli...

The Journal of Neuroscience, 2003

The Journal of Neuroscience, 2002

BMC Cell Biology, 2002

BACKGROUND: Mutations in P0, the major protein of the myelin sheath in peripheral nerves, cause t... more BACKGROUND: Mutations in P0, the major protein of the myelin sheath in peripheral nerves, cause the inherited peripheral neuropathies Charcot-Marie-Tooth disease type 1B (CMT1B), Dejerine-Sottas syndrome (DSS) and congenital hypomyelination (CH). We reported earlier a de novo insertional mutation c.662_663GC (Ala221fs) in a DSS patient. The c.662_663GC insertion results in a frame shift mutation Ala221fs altering the C-terminal amino acid

Tissue Engineering Part A, 2013

The Journal of Neuroscience, 2011

The cysteine-rich protein (CRP) family is a subgroup of LIM domain proteins. CRP1, which cross-li... more The cysteine-rich protein (CRP) family is a subgroup of LIM domain proteins. CRP1, which cross-links actin filaments to make actin bundles, is the only CRP family member expressed in the CNS with little known about its function in nerve cells. Here, we report that CRP1 colocalizes with actin in the filopodia of growth cones in cultured rat hippocampal neurons. Knockdown of CRP1 expression by short hairpin RNA interference results in inhibition of filopodia formation and dendritic growth in neurons. Overexpression of CRP1 increases filopodia formation and neurite branching, which require its actin-bundling activity. Expression of CRP1 with a constitutively active form of Cdc42, a GTPase involved in filopodia formation, increases filopodia formation in COS-7 cells, suggesting cooperation between the two proteins. Moreover, we demonstrate that neuronal activity upregulates CRP1 expression in hippocampal neurons via Ca2+influx after depolarization. Ca2+/calmodulin-dependent protein kina...

The Journal of Neuroscience, 2008

Extensive neuronal cell death during development is believed to be due to a limiting supply of ne... more Extensive neuronal cell death during development is believed to be due to a limiting supply of neurotrophic factors.In vitrostudies suggest that axon guidance molecules directly regulate neuronal survival, raising the possibility that they play a direct role in neuronal cell deathin vivo. However, guidance errors may also influence survival indirectly due to loss of target-derived neurotrophic support. The role of guidance molecules in neuronal deathin vivohas thus been difficult to decipher. Semaphorin3A, a repulsive guidance cue for sensory neurons, can induce sensory neuron deathin vitro. Null mice studies of the Semaphorin3A coreceptors showed that guidance activity is mediated by PlexinA4, but PlexinA3 partially compensates in PlexinA4−/−mice. Here we demonstrate that both Plexins contribute to Sema3A-induced cell deathin vitro, albeit in a different hierarchy. PlexinA3 is absolutely required, while PlexinA4 makes a smaller contribution to cell death. We found that PlexinA3−/−m...

The Journal of cell biology, 1992

To gain insights into the functional role of the molecular association between neural adhesion mo... more To gain insights into the functional role of the molecular association between neural adhesion molecules and extracellular matrix constituents, soluble forms of the myelin-associated glycoprotein (MAG) and the neural cell adhesion molecule (N-CAM), representing most of the extracellular domains of the molecules, were investigated in their ability to modify fibrillogenesis of collagen type I. MAG and N-CAM retarded the rate of fibril formation, as measured by changes in turbidity, and increased the diameter of the fibrils formed, but did not change the banding pattern when compared to collagen type I in the absence of adhesion molecules. Scatchard plot analysis of the binding of MAG and N-CAM to the fibril-forming collagen types I, II, III, and V suggest one binding site for N-CAM and two binding sites for MAG. Binding of MAG, but not of N-CAM, to collagen type I was decreased during fibril formation, probably due to a reduced accessibility of one binding site for MAG during fibrillo...

Proceedings of the National Academy of Sciences, 2002

Myelin-associated glycoprotein (MAG) binds to the nerve cell surface and inhibits nerve regenerat... more Myelin-associated glycoprotein (MAG) binds to the nerve cell surface and inhibits nerve regeneration. The nerve cell surface ligand(s) for MAG are not established, although sialic acid-bearing glycans have been implicated. We identify the nerve cell surface gangliosides GD1a and GT1b as specific functional ligands for MAG-mediated inhibition of neurite outgrowth from primary rat cerebellar granule neurons. MAG-mediated neurite outgrowth inhibition is attenuated by ( i ) neuraminidase treatment of the neurons; ( ii ) blocking neuronal ganglioside biosynthesis; ( iii ) genetically modifying the terminal structures of nerve cell surface gangliosides; and ( iv ) adding highly specific IgG-class antiganglioside mAbs. Furthermore, neurite outgrowth inhibition is mimicked by highly multivalent clustering of GD1a or GT1b by using precomplexed antiganglioside Abs. These data implicate the nerve cell surface gangliosides GD1a and GT1b as functional MAG ligands and suggest that the first step ...