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Journal of Molecular and Cellular... May 2021The intracardiac nervous system (ICNS) is composed of neurons, in association with Schwann cells (SC) and endoneurial cardiac fibroblasts (ECF). Besides heart rhythm...
BACKGROUND
The intracardiac nervous system (ICNS) is composed of neurons, in association with Schwann cells (SC) and endoneurial cardiac fibroblasts (ECF). Besides heart rhythm control, recent studies have implicated cardiac nerves in postnatal cardiac regeneration and cardiomyocyte size regulation, but cardiac SC and ECF remain understudied. During the postnatal period, the ICNS undergoes intense remodeling with nerve fasciculation and elongation throughout the myocardium, partially guided by the extracellular matrix (ECM). Here we report the origins, heterogeneity, and functions of SC and ECF that develop in proximity to neurons during postnatal ICNS maturation.
METHODS AND RESULTS
Periostin lineage (Postn+) cells include cardiac Remak SC and ECF during the postnatal period in mice. The developmental origins of cardiac SC and ECF were examined using Rosa26 reporter mice bred with Wnt1Cre, expressed in Neural crest (NC)-derived lineages, or tamoxifen-inducible Tcf21MerCreMer, expressed predominantly in epicardial-derived fibroblast lineages. ICNS components are NC-derived with the exceptions of the myelinating Plp1+ SC and the Tcf21+ lineage-derived intramural ventricular ECF. In addition, Postn+ lineage GFAP- Remak SC and ECF are present around the fasciculating cardiac nerves. Whole mount studies of the NC-derived cells confirmed postnatal maturation of the complex ICNS network from P0 to P30. Sympathetic, parasympathetic, and sensory neurons fasciculate from P0 to P7 indicated by co-staining with PSA-NCAM. Ablation of Postn+ cells from P0 to P6 or loss of Periostin leads to reduced fasciculation of cardiac sympathetic nerves. In addition, collagen remodeling surrounding maturing nerves of the postnatal heart is reduced in Postn-null mice.
CONCLUSIONS
Postn+ cells include cardiac SC and ECF during postnatal nerve maturation, and these cells have different embryonic origins. At P7, the Postn+ cells associated with cardiac nerves are mainly Remak SC and ECF. Ablation of the Postn+ cells from P0 to P6 and also loss of Postn in Postn-null mice leads to reduced fasciculation of cardiac nerves at P7.
Topics: Animals; Axon Fasciculation; Cell Adhesion Molecules; Fibroblasts; Gene Expression; Mice; Schwann Cells; Sympathetic Nervous System
PubMed: 33582160
DOI: 10.1016/j.yjmcc.2021.02.001 -
Cerebral Cortex (New York, N.Y. : 1991) Jan 2021A better understanding of genetic influences on early white matter development could significantly advance our understanding of neurological and psychiatric conditions...
A better understanding of genetic influences on early white matter development could significantly advance our understanding of neurological and psychiatric conditions characterized by altered integrity of axonal pathways. We conducted a genome-wide association study (GWAS) of diffusion tensor imaging (DTI) phenotypes in 471 neonates. We used a hierarchical functional principal regression model (HFPRM) to perform joint analysis of 44 fiber bundles. HFPRM revealed a latent measure of white matter microstructure that explained approximately 50% of variation in our tractography-based measures and accounted for a large proportion of heritable variation in each individual bundle. An intronic SNP in PSMF1 on chromosome 20 exceeded the conventional GWAS threshold of 5 x 10-8 (p = 4.61 x 10-8). Additional loci nearing genome-wide significance were located near genes with known roles in axon growth and guidance, fasciculation, and myelination.
Topics: Axons; Chromosomes, Human, Pair 20; Diffusion Magnetic Resonance Imaging; Diffusion Tensor Imaging; Female; Genome-Wide Association Study; Humans; Image Processing, Computer-Assisted; Infant; Infant, Newborn; Male; Myelin Sheath; Nerve Fibers; Phenotype; Polymorphism, Single Nucleotide; Proteasome Endopeptidase Complex; Regression Analysis; White Matter
PubMed: 33009551
DOI: 10.1093/cercor/bhaa266 -
FEBS Open Bio Jan 2018Fasciculation and elongation zeta-1 (FEZ1) protein is involved in axon outgrowth and is highly expressed in the brain. It has multiple interaction partners, with...
Fasciculation and elongation zeta-1 (FEZ1) protein is involved in axon outgrowth and is highly expressed in the brain. It has multiple interaction partners, with functions varying from the regulation of neuronal development and intracellular transport mechanisms to transcription regulation. One of its interactors is retinoic acid receptor (RAR), which is activated by retinoic acid and controls many target genes and physiological process. Based on previous evidence suggesting a possible nuclear role for FEZ1, we wanted to deepen our understanding of this function by addressing the FEZ1-RAR interaction. We performed binding experiments and assessed the interface of interaction between both proteins. We found that FEZ1-RAR interacted with a similar magnitude as RAR to its responsive element DR5 and that the interaction occurred in the coiled-coil region of FEZ1 and in the ligand-binding domain of RAR. Furthermore, cellular experiments were performed in order to confirm the interaction and screen for induced target genes from an 86-gene panel. The analysis of gene expression showed that only in the presence of retinoic acid did FEZ1 induce gene expression. This finding is consistent with data from the literature showing the gene functionally involved in development and acute myeloid leukemia, as is FEZ1.
PubMed: 29321952
DOI: 10.1002/2211-5463.12338 -
PloS One 2012During development, fibroblast growth factors (FGF) are essential for early patterning events along the anterior-posterior axis, conferring positional identity to spinal...
During development, fibroblast growth factors (FGF) are essential for early patterning events along the anterior-posterior axis, conferring positional identity to spinal motor neurons by activation of different Hox codes. In the periphery, signaling through one of four fibroblast growth factor receptors supports the development of the skeleton, as well as induction and maintenance of extremities. In previous studies, FGF receptor 2 (FGFR2) was found to interact with axon bound molecules involved in axon fasciculation and extension, thus rendering this receptor an interesting candidate for the promotion of proper peripheral innervation. However, while the involvement of FGFR2 in limb bud induction has been extensively studied, its role during axon elongation and formation of distinct nervous projections has not been addressed so far. We show here that motor neurons in the spinal cord express FGFR2 and other family members during the establishment of motor connections to the forelimb and axial musculature. Employing a conditional genetic approach to selectively ablate FGFR2 from motor neurons we found that the patterning of motor columns and the expression patterns of other FGF receptors and Sema3A in the motor columns of mutant embryos are not altered. In the absence of FGFR2 signaling, pathfinding of motor axons is intact, and also fasciculation, distal advancement of motor nerves and gross morphology and positioning of axonal projections are not altered. Our findings therefore show that FGFR2 is not required cell-autonomously in motor neurons during the formation of initial motor projections towards limb and axial musculature.
Topics: Animals; Axons; Fasciculation; Fibroblast Growth Factors; Gene Expression Regulation; Gene Expression Regulation, Developmental; Genotype; Mice; Microscopy, Fluorescence; Models, Genetic; Motor Neurons; Receptor, Fibroblast Growth Factor, Type 2; Semaphorin-3A; Signal Transduction; Spinal Cord
PubMed: 22815929
DOI: 10.1371/journal.pone.0041095 -
Developmental Cell Jan 2019Neurite fasciculation through contact-dependent signaling is important for the wiring and function of the neuronal circuits. Here, we describe a type of axon-dendrite...
Neurite fasciculation through contact-dependent signaling is important for the wiring and function of the neuronal circuits. Here, we describe a type of axon-dendrite fasciculation in C. elegans, where proximal dendrites of the nociceptor PVD adhere to the axon of the ALA interneuron. This axon-dendrite fasciculation is mediated by a previously uncharacterized adhesive signaling by the ALA membrane signal SAX-7/L1CAM and the PVD receptor SAX-3/Robo but independent of Slit. L1CAM physically interacts with Robo and instructs dendrite adhesion in a Robo-dependent manner. Fasciculation mediated by L1CAM-Robo signaling aligns F-actin dynamics in the dendrite growth cone and facilitates dynamic growth cone behaviors for efficient dendrite guidance. Disruption of PVD dendrite fasciculation impairs nociceptive mechanosensation and rhythmicity in body curvature, suggesting that dendrite fasciculation governs the functions of mechanosensory circuits. Our work elucidates the molecular mechanisms by which adhesive axon-dendrite signaling shapes the construction and function of sensory neuronal circuits.
Topics: Actin Cytoskeleton; Actins; Animals; Axon Fasciculation; Axons; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cytoskeleton; Dendrites; Growth Cones; Nerve Tissue Proteins; Neural Cell Adhesion Molecule L1; Receptors, Immunologic; Roundabout Proteins
PubMed: 30555000
DOI: 10.1016/j.devcel.2018.10.028 -
Developmental Biology Nov 2013Axon fasciculation is one of the processes controlling topographic innervation during embryonic development. While axon guidance steers extending axons in the accurate...
Axon fasciculation is one of the processes controlling topographic innervation during embryonic development. While axon guidance steers extending axons in the accurate direction, axon fasciculation allows sets of co-extending axons to grow in tight bundles. The Eph:ephrin family has been involved both in axon guidance and fasciculation, yet it remains unclear how these two distinct types of responses are elicited. Herein we have characterized the role of ephrin-B1, a member of the ephrinB family in sensory and motor innervation of the limb. We show that ephrin-B1 is expressed in sensory axons and in the limb bud mesenchyme while EphB2 is expressed in motor and sensory axons. Loss of ephrin-B1 had no impact on the accurate dorso-ventral innervation of the limb by motor axons, yet EfnB1 mutants exhibited decreased fasciculation of peripheral motor and sensory nerves. Using tissue-specific excision of EfnB1 and in vitro experiments, we demonstrate that ephrin-B1 controls fasciculation of axons via a surround repulsion mechanism involving growth cone collapse of EphB2-expressing axons. Altogether, our results highlight the complex role of Eph:ephrin signaling in the development of the sensory-motor circuit innervating the limb.
Topics: Animals; Axons; Cells, Cultured; Embryo, Mammalian; Ephrin-B1; Ephrin-B2; Extremities; Ganglia, Spinal; Growth Cones; Mesoderm; Mice; Mice, Inbred C57BL; Motor Neurons; Mutation; Receptors, Eph Family; Sensory Receptor Cells; Signal Transduction
PubMed: 24056079
DOI: 10.1016/j.ydbio.2013.09.010 -
Frontiers in Cellular Neuroscience 2024During the development of neural circuits, axons are guided by a variety of molecular cues to navigate through the brain and establish precise connections with correct...
During the development of neural circuits, axons are guided by a variety of molecular cues to navigate through the brain and establish precise connections with correct partners at the right time and place. Many axon guidance cues have been identified and they play pleiotropic roles in not only axon guidance but also axon fasciculation, axon pruning, and synaptogenesis as well as cell migration, angiogenesis, and bone formation. In search of receptors for Sema3E in axon guidance, we unexpectedly found that Plexin B3 is highly expressed in retinal ganglion cells of zebrafish embryos when retinal axons are crossing the midline to form the chiasm. Plexin B3 has been characterized to be related to neurodevelopmental disorders. However, the investigation of its pathological mechanisms is hampered by the lack of appropriate animal model. We provide evidence that Plexin B3 is critical for axon guidance . Plexin B3 might function as a receptor for Sema3E while Neuropilin1 could be a co-receptor. The intracellular domain of Plexin B3 is required for Semaphorin signaling transduction. Our data suggest that zebrafish could be an ideal animal model for investigating the role and mechanisms of Sema3E and Plexin B3 .
PubMed: 38628398
DOI: 10.3389/fncel.2024.1292969 -
Cell Reports Aug 2018Length-dependent axonopathy of the corticospinal tract causes lower limb spasticity and is characteristic of several neurological disorders, including hereditary spastic...
Length-dependent axonopathy of the corticospinal tract causes lower limb spasticity and is characteristic of several neurological disorders, including hereditary spastic paraplegia (HSP) and amyotrophic lateral sclerosis. Mutations in Trk-fused gene (TFG) have been implicated in both diseases, but the pathomechanisms by which these alterations cause neuropathy remain unclear. Here, we biochemically and genetically define the impact of a mutation within the TFG coiled-coil domain, which underlies early-onset forms of HSP. We find that the TFG (p.R106C) mutation alters compaction of TFG ring complexes, which play a critical role in the export of cargoes from the endoplasmic reticulum (ER). Using CRISPR-mediated genome editing, we engineered human stem cells that express the mutant form of TFG at endogenous levels and identified specific defects in secretion from the ER and axon fasciculation following neuronal differentiation. Together, our data highlight a key role for TFG-mediated protein transport in the pathogenesis of HSP.
Topics: Axon Fasciculation; Axons; Base Sequence; Humans; Mutation; Neurons; Protein Transport; Proteins; Spastic Paraplegia, Hereditary
PubMed: 30157421
DOI: 10.1016/j.celrep.2018.07.081 -
Developmental Biology Nov 2011Interaction of the axon guidance receptor Neuropilin-1 (Npn-1) with its repulsive ligand Semaphorin 3A (Sema3A) is crucial for guidance decisions, fasciculation, timing...
Interaction of the axon guidance receptor Neuropilin-1 (Npn-1) with its repulsive ligand Semaphorin 3A (Sema3A) is crucial for guidance decisions, fasciculation, timing of growth and axon-axon interactions of sensory and motor projections in the embryonic limb. At cranial levels, Npn-1 is expressed in motor neurons and sensory ganglia and loss of Sema3A-Npn-1 signaling leads to defasciculation of the superficial projections to the head and neck. The molecular mechanisms that govern the initial fasciculation and growth of the purely motor projections of the hypoglossal and abducens nerves in general, and the role of Npn-1 during these events in particular are, however, not well understood. We show here that selective removal of Npn-1 from somatic motor neurons impairs initial fasciculation and assembly of hypoglossal rootlets and leads to reduced numbers of abducens and hypoglossal fibers. Ablation of Npn-1 specifically from cranial neural crest and placodally derived sensory tissues recapitulates the distal defasciculation of mixed sensory-motor nerves of trigeminal, facial, glossopharyngeal and vagal projections, which was observed in Npn-1(-/-) and Npn-1(Sema-) mutants. Surprisingly, the assembly and fasciculation of the purely motor hypoglossal nerve are also impaired and the number of Schwann cells migrating along the defasciculated axonal projections is reduced. These findings are corroborated by partial genetic elimination of cranial neural crest and embryonic placodes, where loss of Schwann cell precursors leads to aberrant growth patterns of the hypoglossal nerve. Interestingly, rostral turning of hypoglossal axons is not perturbed in any of the investigated genotypes. Thus, initial hypoglossal nerve assembly and fasciculation, but not later guidance decisions depend on Npn-1 expression and axon-Schwann cell interactions.
Topics: Abducens Nerve; Animals; Axons; Cell Movement; Cranial Nerves; Embryo, Mammalian; Fasciculation; Female; Hypoglossal Nerve; Immunohistochemistry; Male; Mice; Mice, Knockout; Motor Neurons; Mutation; Neural Crest; Neuropilin-1; SOXE Transcription Factors; Schwann Cells; Semaphorin-3A; Sensory Receptor Cells; Signal Transduction
PubMed: 21925156
DOI: 10.1016/j.ydbio.2011.08.019 -
Neuroscience Letters Dec 2010Voltage-gated Na+ channel (VGSC) β Subunits are not "auxiliary." These multi-functional molecules not only modulate Na+ current (I(Na)), but also function as cell... (Review)
Review
Voltage-gated Na+ channel (VGSC) β Subunits are not "auxiliary." These multi-functional molecules not only modulate Na+ current (I(Na)), but also function as cell adhesion molecules (CAMs)-playing roles in aggregation, migration, invasion, neurite outgrowth, and axonal fasciculation. β subunits are integral members of VGSC signaling complexes at nodes of Ranvier, axon initial segments, and cardiac intercalated disks, regulating action potential propagation through critical intermolecular and cell-cell communication events. At least in vitro, many β subunit cell adhesive functions occur both in the presence and absence of pore-forming VGSC α subunits, and in vivo β subunits are expressed in excitable as well as non-excitable cells, thus β subunits may play important functional roles on their own, in the absence of α subunits. VGSC β1 subunits are essential for life and appear to be especially important during brain development. Mutations in β subunit genes result in a variety of human neurological and cardiovascular diseases. Moreover, some cancer cells exhibit alterations in β subunit expression during metastasis. In short, these proteins, originally thought of as merely accessory to α subunits, are critical players in their own right in human health and disease. Here we discuss the role of VGSC β subunits in the nervous system.
Topics: Animals; Axons; Cell Adhesion Molecules; Cell Movement; Epilepsy; Humans; Ion Channel Gating; Mental Disorders; Mutation; Nerve Degeneration; Nervous System; Neurites; Protein Subunits; Sodium Channels
PubMed: 20600605
DOI: 10.1016/j.neulet.2010.06.050