Multipolar Morphologies Research Articles

Effects of HDAC inhibitors on neuroblastoma SH-SY5Y cell differentiation into mature neurons via the Wnt signaling pathway

Histone deacetylase (HDAC) inhibitors affect cell homeostasis, gene expression, and cell cycle progression and promote cell terminal differentiation or apoptosis. However, the effect of HDAC inhibition on SH-SY5Y cells, which are neuroblastoma cells capable of differentiating into neurons under specific conditions, such as in the presence of retinoic acid (RA), is unknown. In this study, we hypothesized that HDAC inhibitors induced the neuronal differentiation of SH-SY5Y cells. To test this hypothesis, we used phase contrast microscopy, immunocytochemistry (ICC), qPCR, and western blotting analysis. MS-275 and valproic acid (VPA), two HDAC inhibitors, were selected to evaluate neuronal differentiation. It was confirmed that cells treated with MS-275 or VPA differentiated into mature neurons, which were distinguished by bipolar or multipolar morphologies with elongated branches. In addition, the mRNA expression of neuronal markers (Tuj1 and NEFH) and the oligodendrocyte marker (CNP) was significantly increased with MS-275 or VPA treatment compared to that with RA treatment. In addition, the protein expression of the other neuronal markers, Tuj1 and NeuN, was highly increased with HDAC inhibitor treatments compared to that with RA treatment. Furthermore, we confirmed that noncanonical Wnt signaling was upregulated by HDAC inhibitors via MAPK signaling and the Wnt/JNK pathway. Therefore, both MS-275 and VPA promoted the differentiation of SH-SY5Y cells into mature neurons via the Wnt signaling pathway.

Homeostatic Roles of the Proteostasis Network in Dendrites.

Cellular protein homeostasis, or proteostasis, is indispensable to the survival and function of all cells. Distinct from other cell types, neurons are long-lived, exhibiting architecturally complex and diverse multipolar projection morphologies that can span great distances. These properties present unique demands on proteostatic machinery to dynamically regulate the neuronal proteome in both space and time. Proteostasis is regulated by a distributed network of cellular processes, the proteostasis network (PN), which ensures precise control of protein synthesis, native conformational folding and maintenance, and protein turnover and degradation, collectively safeguarding proteome integrity both under homeostatic conditions and in the contexts of cellular stress, aging, and disease. Dendrites are equipped with distributed cellular machinery for protein synthesis and turnover, including dendritically trafficked ribosomes, chaperones, and autophagosomes. The PN can be subdivided into an adaptive network of three major functional pathways that synergistically govern protein quality control through the action of (1) protein synthesis machinery; (2) maintenance mechanisms including molecular chaperones involved in protein folding; and (3) degradative pathways (e.g., Ubiquitin-Proteasome System (UPS), endolysosomal pathway, and autophagy. Perturbations in any of the three arms of proteostasis can have dramatic effects on neurons, especially on their dendrites, which require tightly controlled homeostasis for proper development and maintenance. Moreover, the critical importance of the PN as a cell surveillance system against protein dyshomeostasis has been highlighted by extensive work demonstrating that the aggregation and/or failure to clear aggregated proteins figures centrally in many neurological disorders. While these studies demonstrate the relevance of derangements in proteostasis to human neurological disease, here we mainly review recent literature on homeostatic developmental roles the PN machinery plays in the establishment, maintenance, and plasticity of stable and dynamic dendritic arbors. Beyond basic housekeeping functions, we consider roles of PN machinery in protein quality control mechanisms linked to dendritic plasticity (e.g., dendritic spine remodeling during LTP); cell-type specificity; dendritic morphogenesis; and dendritic pruning.

Guided growth with aligned neurites in adult spiral ganglion neurons cultured in vitro on silicon micro-pillar substrates

Objective. Assessment of the relationship between the topographical organization of silicon micro-pillar surfaces (MPS) on guidance and neural alignment of adult spiral ganglion neurons (SGN) and use of the otosurgical approach as an alternative for the extraction and isolation of SGNs from adult guinea pigs. Approach. SGNs from adult guinea pigs were isolated using conventional and otosurgical approach for in vitro cell culturing on MPS of various micro-pillar widths (1–5.6 µm) and spacing (0.6–15 µm). Cell cultures were compared morphologically with neuronal cultures on control glass coverslips. Main results. We found enhanced SGN in vitro cultures in MPS areas with small and intermediate inter-pillar spacing (from 0.6 µm to 3.2 µm) as well as in MPS areas with wider pillars (from 1.8 µm to 4 µm) compared to MPS flat zones and control glass coverslips. Scanning electron microscopy (SEM) images highlighted how neurites of SGNs follow straight lines by growing on top and between micro-pillars. Only micro-pillars with small and intermediate pillar spacings favor neurite alignment along preferred angles (30°, 90°, and 150°), while pillars with wider spacing produced less aligned neurites. We found propensity of adult SGNs grown on MPSs to attain more bipolar and multipolar morphologies. Additionally, we observed reduced interaction between neuronal and glial cells compared to control glass coverslips. Finally, we found that the otosurgical approach was more beneficial for SGN survival on glass coverslips and MPS flat surfaces than the conventional method. Significance. MPS with specific architecture supports the guided growth of adult SGNs in vitro and controls adult SGN development and behavior.

Spatio-kinematical model of the collimated molecular outflow in the water-fountain nebula IRAS 16342–3814

Context. Water-fountain nebulae are asymptotic giant branch (AGB) and post-AGB objects that exhibit high-velocity outflows traced by water-maser emission. Their study is important for understanding the interaction between collimated jets and the circumstellar material that leads to the formation of bipolar and/or multi-polar morphologies in evolved stars. Aims. The aim of this paper is to describe the three-dimensional morphology and kinematics of the molecular gas of the water-fountain nebula IRAS 16342−3814. Methods. Data was retrieved from the ALMA archive for analysis using a simple spatio-kinematical model. The software SHAPE was employed to construct a three-dimensional, spatio-kinematical model of the molecular gas in IRAS 16342−3814, and to then reproduce the intensity distribution and position-velocity diagram of the CO emission from the ALMA observations to derive the morphology and velocity field of the gas. Data from CO(J = 1 → 0) supported the physical interpretation of the model. Results. A spatio-kinematical model that includes a high-velocity collimated outflow embedded within material expanding at relatively lower velocity reproduces the images and position-velocity diagrams from the observations. The derived morphology is in good agreement with previous results from IR and water-maser emission observations. The high-velocity collimated outflow exhibits deceleration across its length, while the velocity of the surrounding component increases with distance. The morphology of the emitting region, the velocity field, and the mass of the gas as function of velocity are in excellent agreement with the properties predicted for a molecular outflow driven by a jet. The timescale of the molecular outflow is estimated to be ~70–100 yr. The scalar momentum carried by the outflow is much larger than it can be provided by the radiation of the central star. An oscillating pattern was found associated with the high-velocity collimated outflow. The oscillation period of the pattern is T ≈ 60–90 yr and its opening angle is θop ≈ 2°. Conclusions. The CO (J = 3 → 2) emission in IRAS 16342−3814 is interpreted in terms of a jet-driven molecular outflow expanding along an elongated region. The position-velocity diagram and the mass spectrum reveal a feature due to entrained material that is associated with the driving jet. This feature is not seen in other more evolved objects that exhibit more developed bipolar morphologies. It is likely that the jet in those objects has already disappeared since it is expected to last only for a couple hundred years. This strengthens the idea that water fountain nebulae are undergoing a very short transition during which they develop the collimated outflows that shape the circumstellar envelopes. The oscillating pattern seen in the CO high-velocity outflow is interpreted as due to precession with a relatively small opening angle. The precession period is compatible with the period of the corkscrew pattern seen at IR wavelengths. We propose that the high-velocity molecular outflow traces the underlying primary jet that produces such a pattern.

Planetary Nebulae, Morphology and Binarity, and the relevance to AGB Stars

AbstractThe dramatic transformation of the spherical outflows of AGB stars into the extreme aspherical geometries seen during the planetary nebula (PN) phase is widely believed to be linked to binarity and is likely driven by the associated production of fast jets and central disks/torii. We first briefly summarize results from the imaging surveys of large samples of young PNe and pre-PNe with HST which show that almost all objects have bipolar, multipolar and elliptical morphologies, with widespread presence of point-symmetric structure. We describe a relatively new technique of using UV photometic observations of large AGB star samples to search for binarity and associated accretion activity, and follow-up studies using UV spectroscopy and X-ray observations. We present results from studies of individual objects in transition to the PN phase, highlighting observational techniques being used to determine jet properties that can constrain the accretion modes that power these jets.

Distribution and morphology of gonadotropin-releasing hormone neurons in the hypothalamus of an induced ovulator – The llama (Lama glama)

Gonadotropin-releasing hormone (GnRH) is a decapeptide involved in the regulation of reproduction in all mammals, but the distribution of GnRH neurons within the brain varies widely among species. The objective of the present study was to characterize the number and distribution of GnRH neurons in the hypothalamus and preoptic area of llamas, an induced ovulator. The brains of female llamas (n = 4) were fixed, frozen and sectioned serially every 50 µm in the transverse (coronal) plane. Every 10th section was stained for immunohistochemical detection of GnRH-positive neuron cell bodies and fibers by incubation with 3,3′-diaminobenzidine. The number of counted immunoreactive cells ranged from 222 to 250 (≈241 ± 13 cells in the preoptic area and hypothalamus per animal) and were localized in the medio-basal hypothalamus (44.3%), anterior hypothalamus (27%), preoptic area (14.9%), diagonal band of Broca/medial septum (13.4%), and mammillary area (0.5%). The immunoreactive cells were not localized in specific hypothalamic nuclei, but rather appeared to be distributed diffusely. The highest concentration of immunoreactive neuron fibers was in the median eminence (P < 0.05), but fibers were identified in most of the areas analyzed, including the neurohypophysis. The GnRH neurons within the hypothalamus displayed monopolar (33%), bipolar (39%), and multipolar (28%) morphologies. The bipolar type was most common in the medio-basal region (40%; P < 0.05). We conclude that GnRH neurons and fibers form a network within the anterior and medio-basal hypothalamus of llamas, suggesting the central location of mechanisms controlling reproductive processes in llamas (i.e., induced ovulation).

The Krüppel-Like Factor Dar1 Determines Multipolar Neuron Morphology.

The three basic morphological types of neurons--unipolar, bipolar, and multipolar--are important for information processing and wiring of neural circuits. Little progress has been made toward understanding the molecular and cellular programs that generate these types since their discovery over a century ago. It is generally assumed that basic morphological types of neurons are determined by the number of dendrites growing out from the cell body. Here, we show that this model alone is insufficient. We introduce the positioning of nucleus as a critical factor in this process and report that the transcription factor Dar1 determines multipolar neuron morphology in postmitotic neurons by regulating genes involved in nuclear positioning.

AN ASYMMETRIC JET-LAUNCHING MODEL FOR THE PROTOPLANETARY NEBULA CRL 618

We propose an asymmetrical jet ejection mechanism in order to model the mirror symmetry observed in the lobe distribution of some protoplanetary nebulae (pPNe), such as the pPN CRL 618. 3D hydrodynamical simulations of a precessing jet launched from an orbiting source were carried out including an alternation in the ejections of the two outflow lobes, depending on which side of the precessing accretion disk is hit by the accretion column from a Roche lobe-filling binary companion. Both synthetic optical emission maps and position-velocity (PV) diagrams were obtained from the numerical results with the purpose of carrying out a direct comparison with observations. Depending on the observer's point of view, multipolar morphologies are obtained which exhibit a mirror symmetry at large distances from the central source. The obtained lobe sizes and their spatial distribution are in good agreement with the observed morphology of the pPN CRL 618. We also obtain that the kinematic ages of the fingers are similar to those obtained in the observations.

A Quantitative Comparison of Human HT-1080 Fibrosarcoma Cells and Primary Human Dermal Fibroblasts Identifies a 3D Migration Mechanism with Properties Unique to the Transformed Phenotype

Here, we describe an engineering approach to quantitatively compare migration, morphologies, and adhesion for tumorigenic human fibrosarcoma cells (HT-1080s) and primary human dermal fibroblasts (hDFs) with the aim of identifying distinguishing properties of the transformed phenotype. Relative adhesiveness was quantified using self-assembled monolayer (SAM) arrays and proteolytic 3-dimensional (3D) migration was investigated using matrix metalloproteinase (MMP)-degradable poly(ethylene glycol) (PEG) hydrogels (“synthetic extracellular matrix” or “synthetic ECM”). In synthetic ECM, hDFs were characterized by vinculin-containing features on the tips of protrusions, multipolar morphologies, and organized actomyosin filaments. In contrast, HT-1080s were characterized by diffuse vinculin expression, pronounced β1-integrin on the tips of protrusions, a cortically-organized F-actin cytoskeleton, and quantitatively more rounded morphologies, decreased adhesiveness, and increased directional motility compared to hDFs. Further, HT-1080s were characterized by contractility-dependent motility, pronounced blebbing, and cortical contraction waves or constriction rings, while quantified 3D motility was similar in matrices with a wide range of biochemical and biophysical properties (including collagen) despite substantial morphological changes. While HT-1080s were distinct from hDFs for each of the 2D and 3D properties investigated, several features were similar to WM239a melanoma cells, including rounded, proteolytic migration modes, cortical F-actin organization, and prominent uropod-like structures enriched with β1-integrin, F-actin, and melanoma cell adhesion molecule (MCAM/CD146/MUC18). Importantly, many of the features observed for HT-1080s were analogous to cellular changes induced by transformation, including cell rounding, a disorganized F-actin cytoskeleton, altered organization of focal adhesion proteins, and a weakly adherent phenotype. Based on our results, we propose that HT-1080s migrate in synthetic ECM with functional properties that are a direct consequence of their transformed phenotype.

Thrombospondin 1 promotes synaptic formation in bone marrow-derived neuron-like cells.

In this study, a combination of growth factors was used to induce bone marrow mesenchymal stem cells differentiation into neuron-like cells, in a broader attempt to observe the role of thrombospondin 1 in synapse formation. Results showed that there was no significant difference in the differentiation rate of neuron-like cells between bone marrow mesenchymal stem cells with thrombospondin induction and those without. However, the cell shape was more complex and the neurites were dendritic, with unipolar, bipolar or multipolar morphologies, after induction with thrombospondin 1. The induced cells were similar in morphology to normal neurites. Immunohistochemical staining showed that the number of positive cells for postsynaptic density protein 95 and synaptophysin 1 protein was significantly increased after induction with thrombospondin 1. These findings indicate that thrombospondin 1 promotes synapse formation in neuron-like cells that are differentiated from bone marrow mesenchymal stem cells.

Electrical and Morphological Characteristics of Anteroventral Periventricular Nucleus Kisspeptin and Other Neurons in the Female Mouse

Neurons in the rodent anteroventral periventricular nucleus (AVPV) play a key role in integrating circadian and gonadal steroid hormone information in the control of fertility. In particular, estradiol-sensitive kisspeptin neurons located in the AVPV, and adjacent structures [together termed the rostral periventricular area of the third ventricle (RP3V)], are critical for puberty onset and the preovulatory LH surge. The present study aimed to establish the morphological and electrical firing characteristics of RP3V neurons, including kisspeptin neurons, in the adult female mouse. Cell-attached electrical recordings, followed by juxtacellular dye filling, of 129 RP3V neurons in the acute brain slice preparation revealed these cells to exhibit multipolar (53%), bipolar (43%), or unipolar (4%) dendritic morphologies along with silent (16%), irregular (41%), bursting (25%), or tonic (34%) firing patterns. Postrecording immunocytochemistry identified 17 of 100 filled RP3V cells as being kisspeptin neurons, all of which exhibited complex multipolar dendritic trees and significantly (P < 0.05) higher bursting or high tonic firing rates compared with nonkisspeptin neurons. The firing pattern of RP3V neurons fluctuated across the estrous cycle with a significant (P < 0.05) switch from irregular to tonic firing patterns found on proestrus. A similar nonsignificant trend was found for kisspeptin neurons. All RP3V neurons responded to gamma-aminobutyric acid and glutamate, about 10% to RFamide-related peptide-3, about 5% to vasopressin, 0% to vasoactive intestinal peptide, and 0% to kisspeptin. These studies provide a morphological and electrical description of AVPV/RP3V neurons and demonstrate their cycle-dependent firing patterns along with an unexpected lack of acute response to the circadian neuropeptides.

Blowing up warped disks in 3D

The Generalized Interacting Stellar Winds model has been very successful in explaining observed cylindrical and bipolar shapes of planetary nebulae. However, many nebulae have a multipolar or point-symmetric shape. Previous two-dimensional calculations showed that these seemingly enigmatic forms can be reproduced by a two-wind model in which the confining disk is warped, as is expected to occur in irradiated disks. In this paper we present the extension to fully three-dimensional Adaptive Mesh Refinement simulations using the publicly available hydrodynamics package Flash. We briefly describe the mechanism leading to a radiation driven warped disk, and give an equation for its shape. We derive time scales related to the disk and compare them to the radiative cooling time scale of the gas, thereby determining the relevant part of parameter space. By comparing two-dimensional calculations including realistic radiative cooling through a cooling curve, with ones employing a low value for the adiabatic index γ, we show that the latter, computationally less expensive approach, is a valid approximation for treating cooling in our nebulae. The results of the fully three-dimensional wind-disk simulations show our mechanism to be capable of producing a plethora of multipolar (and quadrupolar) morphologies, which can explain the observed shape of a number of (proto-)planetary nebulae.

Expression of nitric oxide system in clinically evaluated cases of Alzheimer's disease

The expression of neuronal nitric oxide (nNOS) and inducible nitric oxide (iNOS) as isoforms of the nitric oxide synthase (NOS) as well as nitrotyrosine as an end product of protein nitration was analyzed in sections of temporal cortex taken from postmortem brains of patients with Alzheimer's disease (AD). The patients were evaluated by the Clinical Dementia Rating scale (CDR0–CDR3) and studied in the Memory and Aging Project (MAP) of the Washington University Alzheimer Disease Research Center (ADCR). With the use of immunocytochemical procedures, neurons immunoreactive to nNOS were found to show large and small multipolar and pyramidal morphologies over the entire chronic AD evolution. The iNOS and nitrotyrosine immunoreactivities were also found in pyramidal-like cortical neurons and glial cells. Here, we speculate on the interaction among all specific neurodegenerative changes in AD and nitric oxide as an additional contribution to neuronal death in AD.

Multi-polar Structures in Young Planetary and Protoplanetary Nebulae

The imaging of young planetary and proto-planetary nebulae (PNe and PPNe) with unprecedented high angular resolution and dynamic range, using the Hubble Space Telescope, has led to the realisation that almost all of these objects are highly aspherical, with complex multipolar morphologies. The complexity, organization and symmetry of the morphological structures we find is forcing radical changes in, and inspiring fresh theoretical efforts to advance, our understanding of the mass-loss processes during late stellar evolution. In this paper, we review the HST data, and show some of the highlights of our imaging studies. Although the origins of many of the morphological features remains puzzling, we find that the general presence of multipolar structures support a model for PN formation in which the primary agent for shaping PNe are high-speed collimated outflows or jets which operate during the late AGB and/or early post-AGB evolutionary phase, and undergo episodic changes in their orientation (or collimated outflows operate quasi-simultaneously with different orientations).

Distinct brain vascular cell types manifest inducible cyclooxygenase expression as a function of the strength and nature of immune insults.

Induced prostanoid synthesis by cells associated with the cerebral vasculature has been implicated in mediating immune system influences on the CNS, but the cell type(s) involved remain unsettled. To determine whether this might derive from differences in the nature and intensity of the stimuli used to model immune insults, immunochemical and hybridization histochemical methods were used to monitor cyclooxygenase-2 (COX-2) expression alone, or in conjunction with endothelial, perivascular, and glial cell markers, in brains of rats treated with varying doses of interleukin-1 (IL-1) or bacterial lipopolysaccharide (LPS). Vehicle-treated animals displayed weak COX-2 expression in the meninges, choroid plexus, and larger blood vessels. Rats challenged intravenously with IL-1beta (1.87-30 microgram/kg) showed a marked increase in the number of vascular-associated cells displaying COX-2-immunoreactivity (ir). More than 90% stained positively for the ED2 macrophage differentiation antigen, identifying them as perivascular cells, whereas none coexpressed endothelial or glial cell markers. Low doses of LPS (0.1 microgram/kg) elicited a similar response profile, but higher doses (2-100 microgram/kg) provoked COX-2 expression in a progressively greater number of cells exhibiting distinct round or multipolar morphologies, corresponding to cells expressing endothelial (RECA-1) or perivascular (ED2) cell antigens, respectively. Similarly, ultrastructural analysis localized COX-2-ir to the perinuclear region of endothelial cells of LPS-treated but not IL-1-treated rats. We conclude that perivascular cells exhibit the lower threshold to COX-2 expression in response to either IL-1 or endotoxin treatment, and that enzyme expression by endothelial cells requires one or more facets of the more complex immune stimulus presented by LPS.

Distinct Brain Vascular Cell Types Manifest Inducible Cyclooxygenase Expression as a Function of the Strength and Nature of Immune Insults

Induced prostanoid synthesis by cells associated with the cerebral vasculature has been implicated in mediating immune system influences on the CNS, but the cell type(s) involved remain unsettled. To determine whether this might derive from differences in the nature and intensity of the stimuli used to model immune insults, immunochemical and hybridization histochemical methods were used to monitor cyclooxygenase-2 (COX-2) expression alone, or in conjunction with endothelial, perivascular, and glial cell markers, in brains of rats treated with varying doses of interleukin-1 (IL-1) or bacterial lipopolysaccharide (LPS). Vehicle-treated animals displayed weak COX-2 expression in the meninges, choroid plexus, and larger blood vessels. Rats challenged intravenously with IL-1β (1.87–30 μg/kg) showed a marked increase in the number of vascular-associated cells displaying COX-2-immunoreactivity (ir). More than 90% stained positively for the ED2 macrophage differentiation antigen, identifying them as perivascular cells, whereas none coexpressed endothelial or glial cell markers. Low doses of LPS (0.1 μg/kg) elicited a similar response profile, but higher doses (2–100 μg/kg) provoked COX-2 expression in a progressively greater number of cells exhibiting distinct round or multipolar morphologies, corresponding to cells expressing endothelial (RECA-1) or perivascular (ED2) cell antigens, respectively. Similarly, ultrastructural analysis localized COX-2-ir to the perinuclear region of endothelial cells of LPS-treated but not IL-1-treated rats. We conclude that perivascular cells exhibit the lower threshold to COX-2 expression in response to either IL-1 or endotoxin treatment, and that enzyme expression by endothelial cells requires one or more facets of the more complex immune stimulus presented by LPS.

Electrophysiological characteristics distinguish three classes of neuron in submucosal ganglia of the guinea-pig distal colon.

Intracellular recordings were made from neurons in the submucosal ganglia of the guinea-pig distal colon. The recording electrode contained the intracellular marker biocytin, which was injected into neurons so that their electrophysiological characteristics could be correlated with their shape. Correlations of electrophysiology and shape have not been reported previously for neurons in this region. Three types of neuron were identified on electrophysiological grounds. Neurons of the first type (S neurons) had tetrodotoxin-sensitive soma action potentials, and received fast and slow excitatory synaptic inputs. They had uniaxonal morphologies and may function as secretomotor or possibly vasomotor neurons. The second type (AH neurons) received only slow synaptic input, while the soma action potential had tetrodotoxin-sensitive and -insensitive components with a shoulder on the falling phase and a long-lasting afterhyperpolarisation of the membrane potential following a single action potential. Neurons of this type had multipolar morphologies and provided dense innervation of adjacent submucosal ganglia. These neurons are similar to the submucosal intrinsic primary afferent neurons of the guinea-pig small intestine. The final type of neuron [the low-threshold (LT) neuron] had electrophysiological characteristics that set it apart from those described previously within enteric plexuses. They expressed tetrodotoxin-insensitive voltage-gated soma currents, did not have long-lasting afterhyperpolarisations and received only slow synaptic input. In addition, these neurons were very excitable: they had large input resistances and low thresholds for action potential discharge, and often fired action potentials in the absence of stimulation. Neurons with these characteristics were uniaxonal and thus are likely to be secretomotor or possibly vasomotor neurons. This study has shown that submucosal neurons of the distal colon fall into three distinct types, which can be distinguished by a combination of electrophysiological and morphological criteria.

β1 integrin deficiency impairs migration and differentiation of mouse embryonic stem cell derived neurons

Cell-matrix interaction plays an important role during neuronal development, which is demonstrated by comparing wild type (D3)- and β1 integrin-deficient (G201) embryonic stem cell derived neurons. In D3 preparations complex networks of functionally coupled neurons with bi- and multipolar morphologies develop. In contrast, neuronal differentiation is retarded in G201 derived neurons, recognised by limited migration and restricted morphological differentiation. Furthermore, β1 integrin deficiency causes a delay in expression of major neurotransmitters like GABA and glutamate as well as of synaptophysin. These findings indicate a prominent role of β1 integrin for both morphological and chemical differentiation.

Altered differentiation of cns neural progenitor cells after transplantation into the injured adult rat spinal cord

Denervation of CNS neurons and peripheral organs is a consequence of traumatic SCI. Intraspinal transplantation of embryonic CNS neurons is a potential strategy for reinnervating these targets. Neural progenitor cell lines are being investigated as alternates to embryonic CNS neurons. RN33B is an immortalized neural progenitor cell line derived from embryonic rat raphé nuclei following infection with a retrovirus encoding the temperaturesensitive mutant of SV40 large T-antigen. Transplantation studies have shown that local epigenetic signals in intact or partially neuron-depleted adult rat hippocampal formation or striatum direct RN33B cell differentiation to complex multipolar morphologies resembling endogenous neurons. After transplantation into neuron-depleted regions of the hippocampal formation or striatum, RN33B cells were relatively undifferentiated or differentiated with bipolar morphologies. The present study examines RN33B cell differentiation after transplantation into normal spinal cord and under different lesion conditions. Adult rats underwent either unilateral lesion of lumbar spinal neurons by intraspinal injection of kainic acid or complete transection at the T10 spinal segment. Neonatal rats underwent either unilateral lesion of lumbar motoneurons by sciatic nerve crush or complete transection at the T10 segment. At 2 or 6–7 wk postinjury, lacZ-labeled RN33B cells were transplanted into the lumbar enlargement of injured and age-matched normal rats. At 2 wk posttransplantation, bipolar and some multipolar RN33B cells were found throughout normal rat gray matter. In contrast, only bipolar RN33B cells were seen in gray matter of kainic acid lesioned, sciatic nerve crush, or transection rats. These observations suggest that RN33B cell multipolar morphological differentiation in normal adult spinal cord is mediated by direct cell-cell interaction through surface molecules on endogenous neurons and may be suppressed by molecules released after SCI. They also indicate that the fate of immortalized neural progenitor cell lines in injured CNS must be stringently characterized.

Altered differentiation of CNS neural progenitor cells after transplantation into the injured adult rat spinal cord.

Denervation of CNS neurons and peripheral organs is a consequence of traumatic SCI. Intraspinal transplantation of embryonic CNS neurons is a potential strategy for reinnervating these targets. Neural progenitor cell lines are being investigated as alternates to embryonic CNS neurons. RN33B is an immortalized neural progenitor cell line derived from embryonic rat raphe nuclei following infection with a retrovirus encoding the temperature-sensitive mutant of SV40 large T-antigen. Transplantation studies have shown that local epigenetic signals in intact or partially neuron-depleted adult rat hippocampal formation or striatum direct RN33B cell differentiation to complex multipolar morphologies resembling endogenous neurons. After transplantation into neuron-depleted regions of the hippocampal formation or striatum, RN33B cells were relatively undifferentiated or differentiated with bipolar morphologies. The present study examines RN33B cell differentiation after transplantation into normal spinal cord and under different lesion conditions. Adult rats underwent either unilateral lesion of lumbar spinal neurons by intraspinal injection of kainic acid or complete transection at the T10 spinal segment. Neonatal rats underwent either unilateral lesion of lumbar motoneurons by sciatic nerve crush or complete transection at the T10 segment. At 2 or 6-7 wk postinjury, lacZ-labeled RN33B cells were transplanted into the lumbar enlargement of injured and age-matched normal rats. At 2 wk posttransplantation, bipolar and some multipolar RN33B cells were found throughout normal rat gray matter. In contrast, only bipolar RN33B cells were seen in gray matter of kainic acid lesioned, sciatic nerve crush, or transection rats. These observations suggest that RN33B cell multipolar morphological differentiation in normal adult spinal cord is mediated by direct cell-cell interaction through surface molecules on endogenous neurons and may be suppressed by molecules released after SCI. They also indicate that the fate of immortalized neural progenitor cell lines in injured CNS must be stringently characterized.