Abstract Neuronalmorphology is extremely diverse across and within animal species, developmental stages, brain regions, and cell types. This diversity is functionally important because neuronal structure strongly affects synaptic integration, spiking dynamics, and network con- nectivity. Digital reconstructions of axonal and dendritic arbors are thus essential to quantify and model information processing in the nervous system. NeuroMorpho.Org is an established repository containing tens of thousands of digitally reconstructed neurons shared by several hundred laboratories worldwide. Each neuron is annotated with specific metadata based on the published references and additional details provided by data owners. The number of represented metadata concepts has grown over the years in parallel with the increase of available data. Until now, however, the lack of standardized terminologies and of an adequately structured metadata schema limited the effec- tiveness of user searches. Here we present a new organi- zation of NeuroMorpho.Org metadata grounded on a set of interconnected hierarchies focusing on the main dimen- sions of animal species, anatomical regions, and cell types. We have comprehensively mapped each metadata term in NeuroMorpho.Org to this formal ontology, explicitly resolving all ambiguities caused by synonymy and homo- nymy. Leveraging this consistent framework, we introduce OntoSearch, a powerful functionality that seamlessly enables retrieval of morphological data based on expert knowledge and logical inferences through an intuitive
Other cell-surface receptors that regulate LMC guidance include Ret, Gfra1 (glial cell line derived neurotrophic factor family receptor α 1) and neuropilin 2 (Bonanomi et al., 2012; Huber et al., 2005; Kramer et al., 2006). However, it remains to be determined whether Lhx1 and Isl1 control the expression of these receptors or the neuronal expression of ephrins, which act in motor neurons to control guidance through reverse signaling and cis-inhibition (Bonanomi et al., 2012; Dudanova et al., 2012; Kao and Kania, 2011). Moreover, Lhx1 and Isl1 are required for the mediolateral positioning of LMC cell bodies; although EphA4 regulates the rostrocaudal position of a subset of LMC neurons, Eph receptors do not appear to contribute significantly to mediolateral settling position, suggesting that LIM transcription factors regulate multiple aspects of neuronalmorphology through distinct downstream programs (Coonan et al., 2003; Palmesino et al., 2010). Indeed, a recent study found a requirement for Lhx1 in specifying the mediolateral position of LMC- l cell bodies through upregulation of the reelin signaling protein Dab1 (disabled 1) (Palmesino et al., 2010). As it is not known whether Lhx1 and Isl1 directly bind to their target genes, elucidating the mechanism through which these transcription factors regulate their effectors will be a major challenge for future work. Finally, it will also be of high interest to understand how the individual neurons that make up the major motor nerves are differentiated from each other.
To examine whether miR-196a functions on the above phenotypes through RANBP10, an overexpression construct of RANBP10 under control of an ubiquitin promoter was generated and confirmed (Supplementary Figure 6A and 6B). Additionally, RANBP10 transgenic mice were generated for in vivo studies (Supplementary Figure 6C) . Since miR-196a suppresses the expression of RANBP10 and also provides beneficial functions in the above studies, we hypothesize that RANBP10 might exacerbate neuronalmorphology and functions. Conducting similar examinations, overexpression of RANBP10-DsRed resulted in significantly less branches and shorter neurite outgrowth in N2a (Supplementary Figure 7A and 7B) and primary neurons (Supplementary Figure 7C and 7D). Furthermore, RANBP10 transgenic mice showed the decreased total neurite length (Supplementary Figure 7E and 7F). Moreover, RANBP10 significantly decreased the transport velocity of APP-YFP during retrograde but not anterograde transport (Supplementary Figure 8). These results suggest RANBP10 did exacerbate neuronalmorphology and intracellular transport.
The present study describes the neuronalmorphology of the three types of neurons found in the hippocampal complex of the chick, Gallus domesticus. These neurons have some similarities with the neurons of the reptilian and mammalian homologous structures, which will give some insight into the understanding of evolutionary mechanism of the vertebrate’s brain. The present study will also be important for the experiments involving the single neurons such as Lucifer yellow filling and the study of dendritic spine morphology.
This shading implementation understood to assists in reconstructing neuron morphologies toward realistic visualization. Nevertheless, while smooth lighting was well captured to the polygon surface, others resulted constraint was occur in the neuron connection. The application encountered disconnect neuron segment whilst presented in the virtual environment. Even implementation of this algorithm has produced useful displays of 3D neurons images but also prove to be cumbersome, especially when the algorithm is used to detect and display soft issues for example this such neuron cells. The time required to segment the volume, isolate the desired surface (as is required by any 3D surface display). As such, even though shading application manage to provide smooth and realistic surface, it seem less suitable to be applied by its own for anatomical structure visualization i.e neuronalmorphology. Thus, as the way forward, in this paper introduce an algorithm to overcome such problem to enhance the neuron connection towards smoother surface visualization. It will be valuable by integrating the shading technique with other application approach that will produce better image presentation virtual neuron morphology.
Fig. 6. Myostatin and GDF11 modulate neurite outgrowth and synapse formation. (A) Images of rat brain isolated cortical neuron culture treated as indicated with either DMSO (control), 5 ng/ml TGF β 1 (TGF β ), 10 ng/ml BMP2, 10 ng/ml myostatin (also called GDF8) or 10 ng/ml GDF11 for 5 days commencing from 6 DIV. Cultures were immunostained for excitatory pre- (vGLUT1, green) and post- (PSD95, red) synaptic density markers in addition to a neuronal marker (MAP2, blue). Higher magnification insets underneath correspond to boxed regions in the top row and arrowheads indicate synapses, as indicated by co-labeling with vGLUT1 and PSD95 localized to neurites (MAP2). Scale bars: 15 μ m. (B) Images of rat brain cortical neuron culture treated as in A. Cultures were immunostained for inhibitory pre- (VGAT, green) and post- (GPHN, red) synaptic density markers in addition to a neuronal marker (MAP2, blue). Higher magnification insets underneath correspond to boxed regions in the top row and arrowheads indicate synapses, as indicated by co-labeling with VGAT and GPHN localized to neurites (MAP2). Scale bars: 15 μ m. (C) Microscopy image quantification of the median neurite area occupied per image normalized to control after indicated treatments in A, in addition to a TGF β 1 signaling antagonist (TGF β inhib, 400 nM) and agonist (TGF β bypass, 400 nM) (n=3 independent experiments). (D) Microscopy image quantification of the median synapse frequency per neurite area per image normalized to control after indicated treatments in B. Synapses are indicated by co- labeling with vGLUT1 and PSD95 localized to neurites (MAP2) (n=3 independent experiments). (E) Microscopy image quantification of the median synapse frequency per neurite area per image normalized to control after indicated treatments in B. Synapses are indicated by co-labeling with VGAT and GPHN localized to neurites (MAP2) (n=3 independent experiments). Data are mean±s.e.m. ANOVA+Dunnett ’ s test: *P<0.05; **P<0.01; ***P<0.001; n.s., not significant.
pression, resulting in an increased dendritic spine forma- tion, neurite outgrowth, synaptogenesis, and neurogenesis to strengthen the hippocampal synaptic plasticity and pro- tect the neurons . The n-3 PUFA play an important role in neurogenesis and neurite outgrowth, and also influ- ences the neural membrane biogenesis . Previous stud- ies have shown that docosahexaenoic acid (22:6 n-3; DHA) enhanced neurite outgrowth of hippocampal and cortical neurons  and a deficiency of n-3 fatty acids de- creases the cell body size of neurons in the hippocampus and hypothalamus, and decreases the complexity of den- dritic arborizations on cortical neurons . On the other hand, it has been shown that the larger perikaryal size is accompanied by an increased terminal density, and this combination is positively correlated with an improvement of memory . Membrane function is highly dependent on membrane fluidity and integrity, which in turn are dependent on the lipid composition of the lipid bilayer . Changes in the PUFA content of the neural mem- brane influence membrane fluidity, control the physio- logical functions of the brain, and also regulate synthesis and functions of brain neurotransmitters resulting in changes in synaptic plasticity and spatial cognition [20,21]. Fatty acids are crucial factors that determine the struc- ture and function of biological membranes, including membranes in the nervous system. The brain has a higher lipid amount than any other organ in the body except adi- pose tissue. Neuronal membranes contain high concentra- tions of n-3 and n-6 PUFA . Since dietary n-3 PUFA contribute to the construction and maintenance of the brain , they are also required for optimal cognitive per- formance . In fact, our earlier report showed that rats fed with increasingly higher levels of n-3 PUFA vis-à-vis n-6 PUFA demonstrated marked improvement in cogni- tive, as well as spatial learning abilities . These results pointed
The transmembrane semaphorin, Sema6A, has important roles in axon guidance, cell migration and neuronal connectivity in multiple regions of the nervous system, mediated by context-dependent interactions with plexin receptors, PlxnA2 and PlxnA4. Here, we demon- strate that Sema6A can also signal cell-autonomously, in two modes, constitutively, or in response to higher-order clustering mediated by either PlxnA2-binding or chemically induced multimerisation. Sema6A activation stimulates recruitment of Abl to the cyto- plasmic domain of Sema6A and phos ¡ phorylation of this cytoplasmic tyrosine kinase, as well as phosphorylation of additional cytoskeletal regulators. Sema6A reverse signaling affects the surface area and cellular complexity of non-neuronal cells and aggregation and neurite formation of primary neurons in vitro . Sema6A also interacts with PlxnA2 in cis , which reduces binding by PlxnA2 of Sema6A in trans but not vice versa. These experiments reveal the complex nature of Sema6A biochemical functions and the molecular logic of the context-dependent interactions between Sema6A and PlxnA2.
The effects of srGAP2 on COS7 cells and liposomes as well as its localization to the cell periphery in dissociated cortical neurons prompted us to ask if srGAP2 is required for proper neuronalmorphology. Therefore we first tested the function of srGAP2 in neuronal morphogenesis by designing short-hairpin interfering RNA (shRNA) in order to acutely knockdown srGAP2 expression (Fig. 2.7A). We found that srGAP2 knockdown in E15 cortical neurons led to a significant decrease in both axonal (Fig. 2.7C-D and 2.7F) and dendritic branching after 5 div (Fig. 2.7G-H and 2.7J). Both of these effects were rescued by co-transfection of an untargetable version of srGAP2 (Fig. 2.7E and 2.7I; 2.7F and 2.7J) demonstrating that this is not an off-target effect. The fact that srGAP2 knockdown reduced branching in cortical neurons, a process previously shown to require filopodia formation (Dent et al., 2004), suggest that srGAP2 may promote neurite branching through its ability to induce filopodia in neurons.
Amongst the APP family members APP has a prominent role for dendritic architecture as the knockout of APP alone strongly affected morphology of mature CA1 neu- rons, while lack of either APLP1 or APLP2 did not lead to alterations. However, functional redundancy can only be assessed in combined mutants, as previously demon- strated for the lethality and defects in neuromuscular or cortical development observed in double and triple knockouts [20,21,46]. Indeed, in APP/APLP2-DKO neu- rons we found striking additional defects in the dendritic complexity of apical dendrites as compared to single APP-KO mutants. These findings reveal a novel function of APLP2 for neuronalmorphology in the hippocampus. Further studies are needed to investigate a potentially similar role for APLP1, and can only be fully addressed upon generation of conditional APP/APLP triple mu- tants (see e.g. ). In vitro studies have implicated mul- tiple domains of APP in neurite outgrowth including APP transmembrane isoforms, the secreted APP ecto- domain, or CTFs and several mechanisms have been proposed [45,49,54,55,60,61]. In light of our findings
Background: The common marmoset (Callithrix jacchus) is a New World primate sharing many similarities with humans. Recently developed technology for generating transgenic marmosets has opened new avenues for faithful recapitulation of human diseases, which could not be achieved in rodent models. However, the longer lifespan of common marmosets compared with rodents may result in an extended period for in vivo analysis of common marmoset disease models. Therefore, establishing rapid and efficient techniques for obtaining neuronal cells from transgenic individuals that enable in vitro analysis of molecular mechanisms underlying diseases are required. Recently, several groups have reported on methods, termed direct reprogramming, to generate neuronal cells by defined factors from somatic cells of various kinds of species, including mouse and human. The aim of the present study was to determine whether direct reprogramming technology was applicable to common marmosets. Results: Common marmoset induced neuronal (cjiN) cells with neuronalmorphology were generated from common marmoset embryonic skin fibroblasts (cjF) by overexpressing the neuronal transcription factors: ASCL1, BRN2, MYT1L and NEUROD1. Reverse transcription-polymerase chain reaction of cjiN cells showed upregulation of neuronal genes highly related to neuronal differentiation and function. The presence of neuronal marker proteins was also confirmed by immunocytochemistry. Electrical field stimulation to cjiN cells increased the intracellular calcium level, which was reversibly blocked by the voltage-gated sodium channel blocker, tetrodotoxin, indicating that these cells were functional. The neuronal function of these cells was further confirmed by electrophysiological analyses showing that action potentials could be elicited by membrane depolarization in current-clamp mode while both fast-activating and inactivating sodium currents and outward currents were observed in voltage-clamp mode. The 5-bromodeoxyuridine (BrdU) incorporation assay showed that cjiN cells were directly converted from cjFs without passing a proliferative state.
that cortical compartmentalization closely follows the expression profile of various Eph/ephrin during develop- ment [15–18]. The molecular gradients of different Ephs/ ephrins function in a bidirectional manner wherein their varying dosage determines the levels of either attractive or repulsive force experienced by the developing neuron during migration, synapse formation and function [19– 22]. EphA5 and EphA6 are highly expressed in different layers of the cortex [23–25]. We have shown previously that interfering with EphA5 function using transgenic expression of the truncated receptor lacking the intra- cellular domain resulted in deficits in spatial naviga- tion and impairment in active avoidance, coupled with a decrease in striatal dopamine and serotonin concentra- tions . We also showed that mice with EphA5 dele- tion had reduced level of intermale aggression, similar to that of the deletion of one of the major ligands ephrin- A5 [27, 28]. Genetic inactivation of EphA6 also led to an impairment in learning and memory . Thus it is clear that EphA5 and EphA6 receptors play key roles in brain development and/or behavior regulation. However, spe- cific neuronal changes induced by the deletion of EphA5 or EphA6 have not been well documented. In the present study, we examined neuronalmorphology in the brains of mice with genetic inactivation of EphA5 and EphA6
The cerebellum, from the Latin meaning ‘little brain’, provides one of the most extensively characterised regions of the brain. The cerebellum is composed of predominately two basic neuronal cell types, namely granule and Purkinje cells, along with other constituent cells including glial cells, all of which have distinct cell morphologies, migration patterns and antigenic markers. The spatially and temporally well-defined differentiation of the two neurone populations from this midbrain/hindbrain region of the neural tube epithelium means that the cerebellar neuroepithelium provides an ideal system to study neurogenesis, lineage determination and survival in the brain (Burgoyne et al., 1993). The most abundant type of cell in the cerebellum is the granule cell with the murine cerebellum contains ~ 10^ granule cells, which is more than the number of neurones in the rest of the brain combined (Wechsler-Reya and Scott, 1999; Miyazawa et al., 2000). The importance of these glutamate-secreting cells (Van Vliet et al., 1989) in normal cerebellar function is evident from mutant mice, in which the loss of granule cells leads to severe ataxia (Kofuji et al., 1996; Hamre and Goldwitz, 1997; Mullen et al, 1997).
241 Our systematic review revealed that the effects of drugs used in geriatric patients on 242 neuronal stem cells have not been studied in much detail so far. In fact, the identified 243 publications reported such interactions as an auxiliary finding. Relatively few publications 244 exist on a limited number of drugs, and their heterogeneity was high with respect to the type of 245 experiment (in vivo or in vitro), condition under which the drugs were assessed (physiologic, 246 injury or modified) and the investigated drugs (Table 1 and 2, Supplemental Table 2 and 3). 247 We intentionally chose to investigate neuronal stem cells in their various types and 248 applications because we wanted to provide a comprehensive overview about the interactions of 249 neuronal stem cells and drugs in vitro, in vivo, and in clinical trials. We found that, although 250 there are numerous studies using in vitro and in vivo models, there is no clinical trial 251 investigating drug-stem cell interactions. In addition, we only found studies in cultured 252 neuronal stem cells or endogenous stem cell populations in vivo (Supplemental Table 3). In 253 those studies that investigated transplanted cells, only mesenchymal stem cells, but not 254 neuronal stem cells were used. 22
Hydrocephalus is a common and potentially devastating birth defect affecting the CNS, and its relationship with G protein–coupled receptors (GPCRs) is unknown. We have expressed 2, 4, or 6 copies of a GPCR — the human PAC1 receptor with a 130-kb transgene in the mouse nervous system in a pattern closely resembling that of the endogenous gene. Consistent with PAC1 actions, PKA and PKC activity were elevated in the brains of Tg mice. Remarkably, Tg mice developed dose-dependent hydrocephalus-like characteristics, including enlarged third and lateral ventricles and reduced cerebral cortex, corpus callosum, and subcommissural organ (SCO). Neuronal proliferation and apoptosis were implicated in hydrocephalus, and we observed significantly reduced neuronal proliferation and massively increased neuronal apoptosis in the developing cortex and SCO of Tg embryos, while neurite outgrowth and neuronal migration in vitro remain uncompromised. Ventricular ependymal cilia are crucial for directing cerebrospinal fluid flow, and ependyma of Tg mice exhibited dis- rupted cilia with increased phospho-CREB immunoreactivity. These data demonstrate that altered neuronal proliferation/apoptosis and disrupted ependymal cilia are the main factors contributing to hydrocephalus in PAC1-overexpressing mice. This is the first report to our knowledge demonstrating that misregulation of GPCRs can be involved in hydrocephalus-related neurodevelopmental disorders.
Most arthropods have a complex vascular system in which the limbs are supplied with hemolymph by ar- teries. In insects, this system is greatly reduced and a ventral longitudinal vessel from which such arteries could emanate is lacking . Their thoracic limbs are supplied by sinuses delimited by thin septa of connect- ive tissue which are perforated in the tip region of the appendage enabling a countercurrent hemolymph flow . A comparable condition can also be found in the gonapophyseal appendages in Acheta . However, while in most thoracic limbs and cerci it is unclear how the hemolymph flow is generated, a pumping apparatus exists for each of the ovipositor valves. These organs represent evolutionary novelties having a functional morphology which has not been reported from any other auxiliary heart in insects . The origin of the associated pumping muscle must remain unclear since no unambiguous homologization with any of the serial homologues of the abdominal musculature is possible.
In contrast to cultured neurons, the polarization processes of neurons in vivo have different properties depending on brain region and developmental stage. For example, vertebrate retinal ganglion cells and retinal bipolar cells inherit their polarity (Barnes and Polleux, 2009). When born, they possess a neuroepithelium-like morphology, with apical and basal processes that eventually develop into a dendrite and an axon, respectively (Barnes and Polleux, 2009). By contrast, cortical and hippocampal pyramidal neurons, and cerebellar granule neurons establish their polarity during differentiation (Noctor et al., 2004; Solecki et al., 2006; Funahashi et al., 2014). Cortical pyramidal neurons are generated in the ventricular zone (VZ) and migrate through the subventricular zone towards the intermediate zone (IZ) (Miyata et al., 2004; Noctor et al., 2004). They extend multiple minor neurites and are called multipolar (MP) cells (Miyata et al., 2004; Noctor et al., 2004). One of the minor neurites grows rapidly to become a trailing process, and another develops into a leading process, which finally develop into an axon and a dendrite, respectively (Miyata et al., 2004; Noctor et al., 2004). The remaining minor neurites are retracted and MP cells subsequently transform into bipolar (BP) cells in the IZ. BP cells are completely polarized and migrate towards the cortical plate (CP). Although neuronal polarization can occur in parallel with neuronal migration, how these two processes are coordinated remains elusive. Polarization of neurons in the cerebral cortex serves as a well-studied model for polarity establishment in vivo (Funahashi et al., 2014), and the processes regulating it are discussed in detail below.
or non-coding RNAs and down-regulate their target gene expression. During developmental process, let-7 microRNAs regulate developmental timing or certain microRNAs are over-expressed or under-expressed in diseases such as cancer, metabolic diseases, and cardio- vascular disorders [16–20]. MicroRNAs might be used as a tool to control the biological process of interest even for the treatment of neurodegenerative diseases. Among the variety of microRNAs expressed exclusively in the nervous system, miR-124a is abundantly expressed as neuron-specific miRNAs [21–25]. miR-124a was re- ported to promote neuronal differentiation by triggering brain-specific alternative pre-mRNA splicing [26–30] and was known to participate in neuronal fate determin- ation during spinal cord development , and miR- 124a was necessary for a proper brain development and axogenesis of dentate granule neurons . miR-124a might be able to promote neuronal differentiation of stem or progenitor cells when co-administered with the stem/progenitor cell implants as a differentiation activa- tor. If proven for its efficacy, injection of miR-124a might enhance the feasibility of using progenitor cell implants in intractable neurological disorders.
headstage) and the stationary part (the host). Inside the neuronal interface, signals acquired by the recording electrode arrangement are shaped (pream- pliﬁed, ﬁltered, possibly digitized) by the recording front-end. Either a wired or wireless communication link transfers the signals to the stationary host. In case of communication over wires, some sort of mechanical strain relief solu- tion must be employed if the subject is to be let free. This is typically done by means of a “commutator”, a mechanical device connecting two cables that allows both sides to be rotated freely with respect to each other (Fig. 2.13). The host performs the necessary computation and datalogging steps on the incoming input signals and calculates the stimulation feedback. Stimulation instructions are sent back into the interface where they are applied to the stimulation electrodes by the stimulating front-end.
In contrast to HLA-DR, expression of microglial CD68 tended to be correlated with AUBGC > 2 g/l (rho = 0.44, P = 0.08). Intensity of neuronal and microglial apoptosis was correlated with AUBGC > 2 g/l (rho = 0.53; P = 0.03 and rho = 0.70; P = 0.002) (Table 2, Fig- ure 1). Intensity of neuronal beta-APP expression corre- lated with AUBGC > 2 g/l (rho = 0.61; P = 0.03) (Figure 2). Endothelial iNOS expression was correlated with intensity of neuronal apoptosis (rho = 0.68, P = 0.005) but not with that of microglial apoptosis (rho = 0.34, P = 0.17). The intensities of neuronal and microglial apop- tosis were correlated (rho = 0.56, P = 0.02). Immunos- taining of GLUT3 was not satisfactory. GLUT1 rather stained endothelial cells than neurons and its expression did not vary among patients. Neuronal GLUT4 (Figure 3) and microglial GLUT5 expression (Figure 4) did not correlate with prolonged hyperglycaemia nor with neu- ronal or microglial apoptosis (Table 3). Expressions of endothelial iNOS and microglial GLUT5 were inversely correlated (rho = -0.54; P = 0.03). Neuronal and micro- glial apoptosis were not correlated with SAPS-II at admission, highest SOFA score, duration of septic shock, or with serum sodium (especially hyponatremia), lowest systolic arterial pressure, PaO 2 and SaO 2 . Inten-