Monoclonal antibody to intermediate filament proteins in astrocytes

Effects of circadian rhythm disorder on the hippocampus of SHR and WKY rats

The present study investigated the effects of circadian rhythm disorder (CRD) on the hippocampus of SHR and WKY rats. Male SHR rats (n = 27) and WKY rats (n = 27) were randomly divided into six groups: SHR and WKY normal (N)CR, SHR and WKY CRD 16/8 (CRD16/8), and SHR and WKY CRD 12/12 (CRD12/12). Activity patterns were adjusted using different photoperiods over 90 days and any changes were recorded. Rats were tested in the Morris water maze and in a novel object recognition experiment; serologic analysis, magnetic resonance imaging (diffusion tensor imaging + arterial spin labeling), hippocampal Nissl staining, Fluoro-Jade B staining, and immunohistochemistry were also performed. The results showed that both types of inverted photoperiod reduced CR amplitude and prolonged the circadian period. CRD and hypertension reduced memory performance and novel object recognition and preference. The decreases in memory and preference indices were greater in rats in the CRD12/12 group compared to the CRD16/8 group. CRD and hypertension decreased fractional anisotropy values, the number of neurons and astrocytes in the hippocampus, and the expression of brain-derived neurotrophic factor and synapsin 1; it also enhanced the degeneration of neurons and microglia and reduced blood flow in the hippocampus, and increased nuclear factor κB, caspase, neuron-specific enolase, and interleukin-6 levels. These findings reveal a biological basis for the link between CRD and cognitive decline, which has implications for CRD caused by shift work and other factors.

Neural differentiation on synthetic scaffold materials

The potential of stem cells to differentiate into a variety of subgroups of neural cells makes stem cell differentiation and transplantation a promising candidate for neurodegenerative disorder therapies. However, selective differentiation of stem cells to neurons while preventing glial scar formation is a complex process. Mimicking the natural environment of neural tissue is pivotal, thus various synthetic materials have been developed for this purpose. The synthetic scaffolds can direct stem cells into a neural lineage by including extracellular factors that act on cell fate, which are mainly soluble signals, extracellular matrix proteins and physical factors (e.g. elasticity and topography). This article reviews synthetic materials developed for neural regeneration in terms of their extracellular matrix mimicking properties. Functionalization of synthetic materials by addition of bioactive chemical groups and adjustment of physical properties such as topography, electroactivity and elasticity are discussed.

Extracellular matrix mimetic peptide scaffolds for neural stem cell culture and differentiation

Self-assembled peptide nanofibers form three-dimensional networks that are quite similar to fibrous extracellular matrix (ECM) in their physical structure. By incorporating short peptide sequences derived from ECM proteins, these nanofibers provide bioactive platforms for cell culture studies. This protocol provides information about preparation and characterization of self-assembled peptide nanofiber scaffolds, culturing of neural stem cells (NSCs) on these scaffolds, and analysis of cell behavior. As cell behavior analyses, viability and proliferation of NSCs as well as investigation of differentiation by immunocytochemistry, qRT-PCR, western blot, and morphological analysis on ECM mimetic peptide nanofiber scaffolds are described.

MARCKS modulates radial progenitor placement, proliferation and organization in the developing cerebral cortex

The radial glial cells serve as neural progenitors and as a migratory guide for newborn neurons in the developing cerebral cortex. These functions require appropriate organization and proliferation of the polarized radial glial scaffold. Here, we demonstrate in mice that the myristoylated alanine-rich C-kinase substrate protein (MARCKS), a prominent cellular substrate for PKC, modulates radial glial placement and expansion. Loss of MARCKS results in ectopic collection of mitotically active radial progenitors away from the ventricular zone (VZ) in the upper cerebral wall. Apical restriction of key polarity complexes [CDC42, beta-catenin (CTNNB1), N-cadherin (CDH2), myosin IIB (MYOIIB), aPKCzeta, LGL, PAR3, pericentrin, PROM1] is lost. Furthermore, the radial glial scaffold in Marcks null cortex is compromised, with discontinuous, non-radial processes apparent throughout the cerebral wall and deformed, bulbous, unbranched end-feet at the basal ends. Further, the density of radial processes within the cerebral cortex is reduced. These deficits in radial glial development culminate in aberrant positioning of neurons and disrupted cortical lamination. Genetic rescue experiments demonstrate, surprisingly, that phosphorylation of MARCKS by PKC is not essential for the role of MARCKS in radial glial cell development. By contrast, the myristoylation domain of MARCKS needed for membrane association is essential for MARCKS function in radial glia. The membrane-associated targeting of MARCKS and the resultant polarized distribution of signaling complexes essential for apicobasal polarity may constitute a critical event in the appropriate placement, proliferation and organization of polarized radial glial scaffold in the developing cerebral cortex.

Long-term multilayer adherent network (MAN) expansion, maintenance, and characterization, chemical and genetic manipulation, and transplantation of human fetal forebrain neural stem cells

Human neural stem/precursor cells (hNSC/hNPC) have been targeted for application in a variety of research models and as prospective candidates for cell-based therapeutic modalities in central nervous system (CNS) disorders. To this end, the successful derivation, expansion, and sustained maintenance of undifferentiated hNSC/hNPC in vitro, as artificial expandable neurogenic micro-niches, promises a diversity of applications as well as future potential for a variety of experimental paradigms modeling early human neurogenesis, neuronal migration, and neurogenetic disorders, and could also serve as a platform for small-molecule drug screening in the CNS. Furthermore, hNPC transplants provide an alternative substrate for cellular regeneration and restoration of damaged tissue in neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease. Human somatic neural stem/progenitor cells (NSC/NPC) have been derived from a variety of cadaveric sources and proven engraftable in a cytoarchitecturally appropriate manner into the developing and adult rodent and monkey brain while maintaining both functional and migratory capabilities in pathological models of disease. In the following unit, we describe a new procedure that we have successfully employed to maintain operationally defined human somatic NSC/NPC from developing fetal, pre-term post-natal, and adult cadaveric forebrain. Specifically, we outline the detailed methodology for in vitro expansion, long-term maintenance, manipulation, and transplantation of these multipotent precursors.

Spatiotemporal characteristics of astroglial death in the rat hippocampo-entorhinal complex following pilocarpine-induced status epilepticus

Recently we reported that astroglial loss and subsequent gliogenesis in the dentate gyrus play a role in epileptogenesis following pilocarpine-induced status epilepticus (SE). In the present study we investigated whether astroglial damages in the hippocampo-entorhinal complex following SE are relevant to pathological or electrophysiological properties of temporal lobe epilepsy. Astroglial loss/damage was observed in the entorhinal cortex and the CA1 region at 4 weeks and 8 weeks after SE, respectively. These astroglial responses in the hippocampo-entorhinal cortex were accompanied by hyperexcitability of the CA1 region (impairment of paired-pulse inhibition and increase in excitability ratio). Unlike the dentate gyrus and the entorhinal cortex, CA1 astroglial damage was protected by conventional anti-epileptic drugs. alpha-Aminoadipic acid (a specific astroglial toxin) infusion into the entorhinal cortex induced astroglial damage and changed the electrophysiological properties in the CA1 region. Astroglial regeneration in the dentate gyrus and the stratum oriens of the CA1 region was found to originate from gliogenesis, while that in the entorhinal cortex and stratum radiatum of the CA1 region originated from in situ proliferation. These findings suggest that regional specific astroglial death/regeneration patterns may play an important role in the pathogenesis of temporal lobe epilepsy.

Microglial expression of peptidylarginine deiminase 2 in the prenatal rat brain

Peptidylarginine deiminases (PADs) are Ca^2t+-dependant post-translational modification enzymes that catalyze the citrullination of protein arginyl residues. PAD type 2 (PAD2) is thought to be involved in some processes of neurodegeneration and myelination in the central nervous system. In this study, we found PAD2-positive cells in rat cerebra in 19-to 21-day old embryos, i.e. at a developmental stage well before myelination begins. Most of the cells were microglial marker-positive cells found mainly in the prospective medulla, and others were microglial marker-negative cells found mainly in the prospective dentate gyrus of the hippocampus. The former seemed to be in an activated state as judged by morphological criteria. The specificity of the enzyme activity, immunoblotting and reverse transcriptase-polymerase chain reaction analyses revealed that these cells expressed PAD2 and not PAD1, PAD3 or PAD4. Our data is indicative of microglial expression of PAD2 in the prenatal developing cerebrum.

Oligodendrocyte and astrocyte development in rodents: an in situ and immunohistological analysis during embryonic development

Lineally related multipotent neuroepithelial cells (NEP), neuronal restricted precursors (NRP), and glial restricted precursors (GRP) have been identified in the spinal cord. To determine the sequence of differentiation and identify lineage and stage-specific markers, we have examined the spatiotemporal expression of established glial markers during rodent embryonic development and within fetal cell culture. In this report, we show that proliferating stem cells in the developing neural tube do not express any glial markers at E10.5. By E11, however, glial precursors have begun to differentiate and at least two regions of the ventral neural tube containing glial precursor cells can be distinguished, an Nkx2.2/Neurogenin 3 (Ngn3) domain and a platelet-derived growth factor receptor alpha (PDGFRalpha)/Olig2/Sox10 domain. Radial glia, as identified by RC1 immunoreactivity, develop in concert with other glial precursors and can be distinguished by their morphology, spatial distribution, and antigen expression. Astrocytes as assessed by glial fibrillary acidic protein (GFAP) immunoreactivity are first detected at E16. A novel dorsal domain of CD44 immunoreactivity that can be distinguished from the more ventral glial precursor domains can be detected as early as E13.5.

Astrocytic messenger RNA responses to striatal deafferentation in male rat

This investigation describes the schedule and regional distribution of astrocytic responses in striatum following deafferentation by unilateral frontal cortex ablation. In the ipsilateral deafferented striatum, glial fibrillary acidic protein and clusterin (sulfated glycoprotein-2) messengerRNA showed peak elevations by 10 days postlesioning (Northern blots). Vimentin messengerRNA responded faster, with a transient elevation by three days postlesioning. The messengerRNA for glial fibrillary acidic protein, clusterin and vimentin returned toward control levels by 27 days postlesioning. However, the neuronal marker growth-associated protein messengerRNA, was decreased at all postlesion times. By in situ hybridization, the increased glial fibrillary acidic protein messengerRNA and clusterin messengerRNA signals were localized mainly to the dorsal half of the ipsilateral deafferented striatum and followed the same schedule as found by Northern blots. Glial fibrillary acidic protein messengerRNA was widely diffused in the dorsal striatum and was excluded from fascicles of the internal capsule; a similar distribution was found for glial fibrillary acidic protein-immunopositive astrocytes. While clusterin messengerRNA signal showed a distinct clustering, its immunoreactivity appeared as deposits in the deafferented striatal neuropil; Western blots confirmed the immunocytochemical results. By in situ hybridization, vimentin messengerRNA was mostly localized to the cortical wound cavity dorsal to the deafferented striatum and overlapped the distribution of vimentin-immunopositive cells. These findings suggest a coordination of striatal astrocytic messengerRNA responses with the degeneration of corticostriatal afferents. We also compared these same parameters with those from published reports on the hippocampus after deafferenting lesions. Certain astrocyte molecular responses to deafferentation are detected about five days earlier in the hippocampus than in the striatum. This different schedule in response to decortication may pertain to differences in synaptic remodeling in the hippocampus vs striatum.

Characterization of a glial associated antigen GA-1 by monoclonal antibody

A glial antigen (GA-1) was identified by monoclonal antibodies (MAb) raised against C6 rat glioma cells. MAb-7D3 (IgG2a kappa) revealed GA-1 as a single protein band with a Rf value of 0.09 by the use of basic-PAGE Western blot. SDS-PAGE Western blot and radioimmunoprecipitation (RIP) further resolved GA-1 into two subunits with a molecular weight of 200 and 78 kDa respectively. Subcellular localization by immunocytochemical staining revealed its cytosolic presence with a punctate pattern perinuclearly. Significant expression of GA-1 may be detected in 4 glioma or glial cell lines derived from rat brain. However, no expression may be detected in the rest of the 18 mammalian cell lines or primary neural cell cultures examined. All of the above data thereby suggest that GA-1 may be glial specific whereas the epitope of GA-1 defined by MAb-7D3 is species (rat) specific.

4B2: a monoclonal antibody to ganglion and bipolar cells in the retina of the cat, generated by intrasplenic immunization

Using tissue from the inner layers of the retina as the immunogen, we have prepared a monoclonal antibody which is selective for two classes of neuron in the cat retina. The antibody, termed 4B2, was generated by intrasplenic injection, demonstrating that neuron-specific antibodies can be elicited by this technique, which requires only micrograms of immunogen. The 4B2 binds to the somas, dendrites and axons of ganglion cells. Double labelling with 4B2 and with a retrograde tracer injected into the retino-recipient nuclei of the brain demonstrates that, of the cell classes in the ganglion cell layer, 4B2 labels only ganglion cells, and that, amongst ganglion cells, 4B2 is strongly selective for large (alpha-) and medium-sized (beta- and perhaps gamma-) cells. Double labelling with 4B2 and with markers for amacrine cells confirms tht 4B2 does not label amacrine cells. Double labelling with 4B2 and with anti-GFAP confirms that 4B2 does not label the macroglia of the retina. The 4B2 also labels bipolar cells, showing their somas, dendrites and axons. The axons of the labelled cells terminate in large boutons, in the innermost part of the inner plexiform layer and in the ganglion cell layer. This level of termination suggests that 4B2 labels rod bipolars, and perhaps a subgroup of cone bipolars. Double labelling with 4B2 and with markers for amacrine, horizontal and Müller cells indicates that other cell classes with somas in the inner nuclear layer remain unlabelled. In addition, we have examined the ontogeny of 4B2 labelling in the cat retina. The developmental sequence of labelling with 4B2 follows the sequence in which the cells are born, first ganglion and then bipolar cells.

Mitogenic and morphogenic effects of a bovine salivary gland extract on astrocytes and fibroblasts

The presence of mitogenic and morphogenic activity in extracts of bovine salivary (parotid) glands is reported. The crude and partially purified extracts stimulated cultured rat cerebellar cells (astrocytes) and skin fibroblasts to undergo morphogenesis. The incorporation of [3H]thymidine was also stimulated in astrocytes, skin fibroblasts, and established fibroblastic cell lines. Growth-promoting activity was also demonstrated. The expression of maximum mitogenic activity in skin fibroblast cultures, but not kidney fibroblast cultures, required the presence of serum. The biological activity had an apparent native molecular weight greater than 230,000, was heat-sensitive, trypsin-resistant, and slightly sensitive to the action of papain.

Expression of glial filament protein (GFP) in nerve sheaths and non-neural cells re-examined using monoclonal antibodies, with special emphasis on the co-expression of GFP and cytokeratins in epithelial cells of human salivary gland and pleomorphic adenomas

We describe two novel monoclonal antibodies specific for glial filament protein (GFP), i.e., GF12.23 and GF12.24 (both IgG2a]. These cross-react over a broad range of species with epitopes located in the alpha-helical rod domain typical of all intermediate filament (IF) proteins. These monoclonal antibodies were used, in conjunction with other monoclonal GFP antibodies, rabbit antiserum to GFP, and various antibodies to other cytoskeletal proteins, to examine the occurrence of GFP in cells outside of the central nervous system of rodents, cows, and humans. We detected some scattered GFP-containing cells in the neural sheaths in some species but not in others, and we obtained different results when comparing the rabbit antisera with the monoclonal GFP antibodies. In the enteric glia of rats, we observed GFP-positive cells with all of the antibodies used, whereas in human intestine, the various monoclonal antibodies showed no reaction with any intestinal cells. Similarly, no GFP was detected in surface cells of the lens of cows and rats using any of the GFP antibodies, whereas some reaction was seen in murine lens tissue. We were also unable to detect GFP-positive cells in human, bovine, or rat liver with any of the monoclonal antibodies, which is in contrast to the reactivity of the rabbit GFP antisera with some stellate perisinusoidal cells of rat but not bovine or human liver. The possible reasons for the discrepancies between the different species and the different antibody preparations used are discussed. In addition, using double-label immunofluorescence microscopy, we showed that normal human parotid glands contain a certain type of epithelial cell that co-expresses cytokeratins and desmosomal proteins with GFP. The histological distribution of these GFP-positive cells suggests that they represent a subset of the myoepithelial cells present in this tissue. Cells co-expressing cytokeratins and GFP - in some cases, apparently together with vimentin as the third IF protein present - were also identified in tumors derived from this salivary-gland epithelium, i.e., pleomorphic adenomas, in which GFP-positive cells were relatively frequent in the myxoid and chondroid components, thus confirming the work of other investigators. Possible implications for the concept of histogenesis of these tumor cells are discussed, as are possible mechanisms resulting in the co-expression of IF proteins.

Characterization of the anti-neural antibodies in the sera of leprosy patients

Sera from 43 leprosy patients were tested for antibodies that bound to normal human nerve. Thirty-eight percent showed positive staining as demonstrated by indirect immunofluorescence. Only 1 out of 30 control sera tested displayed similar staining. Western blots of myelin and neural intermediate filament (IF) proteins were tested with patient sera. Two of the anti-neural antibody (ANeAb)-positive leprosy sera bound to the P0 protein of PNS myelin. All 17 ANeAb-positive leprosy sera displayed 2 or more bands in the molecular weight range of Mr 45 000-55 000, when tested against IF proteins. One explanation for these findings is that leprosy patients produce antibodies to intermediate filament (IF) proteins released subsequent to the bacterial invasion of the peripheral nerves. The importance of these autoantibodies in the pathogenesis of leprosy is discussed.

Immunohistochemical demonstration of vimentin in human cerebral tumors

The distribution of vimentin (VIM) has been histochemically investigated in 53 cerebral tumors and compared in gliomas to that of glial fibrillary acidic protein (GFAP). In gliomas VIM is less positive than GFAP, but shows the same distribution. It cannot be considered as indicating immaturity of glial tumor cells. VIM is also positive in glial processes of cerebellar pilocytic astrocytomas, in Schwann cells of neurinomas and in endothelial cells of all oncotypes. In medulloblastomas, VIM decorates reactive glia cells. A diffuse positive reaction has been observed in meningiomas. In hemangioblastomas, besides intervascular and endothelial cells, groups of polygonal cells are intensely positive for both VIM and GFAP. The interpretation of VIM in cerebral tumors is largely based on the distribution patterns of this intermediate filament in the developing CNS of rodents.

Characterization of cultured rat oligodendrocytes proliferating in a serum-free, chemically defined medium

A serumless, chemically defined medium has been developed for the culture of oligodendrocytes isolated from primary neonatal rat cerebral cultures. Combined together, insulin, transferrin, and fibroblast growth factor synergistically induced an essentially homogenous population (95-98%) of cells expressing glycerol-3-phosphate dehydrogenase (EC 1.1.1.8) activity to undergo cell division. Proliferating cels were characterized by several criteria: (i) ultrastructural analysis by transmission electron microscopy identified the cell type as an oligodendrocyte; (ii) biochemical assays showed expression of three oligodendrocyte biochemical markers, induction of both glycerol phosphate dehydrogenase and lactate dehydrogenase (EC 1.1.1.27), and presence of 2',3'-cyclic nucleotide 3'-phosphodiesterase (EC 3.1.4.37); and (iii) immunocytochemical staining showed cultures to be 95-98% positive for glycerol phosphate dehydrogenase, 90% for myelin basic protein, 60-70% for galactocerebroside, and 70% for A2B5. Few cells (less than 5%) stained positive for glial fibrillary acidic protein, and none were detected positive for fibronectin.