Evidence in vitro of glial cell priming in the taiep rat
Bertha Alicia León‐ChávezJuan Antonio González-BarriosAraceli UgarteMarco Antonio Meraz‐RíosDaniel Martínez‐Fong
19
Citation
17
Reference
10
Related Paper
Citation Trend
Keywords:
Priming (agriculture)
Neuroglia
Abstract Background There is increasing interest in astrocyte biology because astrocytes have been demonstrated to play prominent roles in physiological and pathological conditions of the central nervous system, including neuroinflammation. To understand astrocyte biology, primary astrocyte cultures are most commonly used because of the direct accessibility of astrocytes in this system. However, this advantage can be hindered by microglial contamination. Although several authors have warned regarding microglial contamination in this system, complete microglial elimination has never been achieved. Methods The number and proliferative potential of contaminating microglia in primary astrocyte cultures were quantitatively assessed by immunocytologic and flow cytometric analyses. To examine the utility of clodronate for microglial elimination, primary astrocyte cultures or MG-5 cells were exposed to liposomal or free clodronate, and then immunocytologic, flow cytometric, and gene expression analyses were performed. The gene expression profiles of microglia-eliminated and microglia-contaminated cultures were compared after interleukin-6 (IL-6) stimulation. Results The percentage of contaminating microglia exceeded 15% and continued to increase because of their high proliferative activity in conventional primary astrocyte cultures. These contaminating microglia were selectively eliminated low concentration of liposomal clodronate. Although primary microglia and MG-5 cells were killed by both liposomal and free clodronate, free clodronate significantly affected the viability of astrocytes. In contrast, liposomal clodronate selectively eliminated microglia without affecting the viability, proliferation or activation of astrocytes. The efficacy of liposomal clodronate was much higher than that of previously reported methods used for decreasing microglial contamination. Furthermore, we observed rapid tumor necrosis factor-α and IL-1b gene induction in conventional primary astrocyte cultures after IL-6 stimulation, which was due to the activation of the Janus kinase/signal transducer and activator of the transcription pathway in contaminating microglia. Conclusions Because contaminating microglia could result in erroneous data regarding the pro-inflammatory properties of astrocytes, astrocyte biology should be studied in the absence of microglial contamination. Our simple method will be widely applicable to experimental studies of astrocyte biology and provide clues for understanding the role of astrocytes in neural development, function and disease.
Primary (astronomy)
Cite
Citations (59)
Neuroglia
Precursor cell
Cite
Citations (34)
Abstract Human genetic diseases and mouse knockouts illustrate that the maintenance of central nervous system myelin requires connexin expression by both astrocytes and oligodendrocytes. Because these cell types express nonoverlapping sets of connexins, the intercellular channels formed between them must be asymmetric with regard to connexin content, defined as heterotypic. Here, we show that oligodendrocyte Cx47 can form heterotypic channels with astrocyte Cx43 or Cx30 but not Cx26, whereas oligodendrocyte Cx32 can functionally interact with astrocyte Cx30 or Cx26 but not Cx43. Thus, as many as four types of intercellular channels could be formed between astrocytes and oligodendrocytes. © 2010 Wiley‐Liss, Inc.
Neuroglia
Cite
Citations (77)
Abstract Reactive gliosis is a response noted after nearly every type of CNS injury and involves both activated microglia and astroglia. Although many investigators believe that reactive glia in some way regulate the survival of injured neurons, the influence of glial elements upon damaged neural tissues remains uncertain. To examine relationships between reactive glia and neurons, secretion products from both microglia and astroglia are tested for their effects upon the survival of cultured neurons. Microglia are found to secrete neurotoxic agents, while astroglia are a source of neuronotrophic factors. Similar patterns of soluble factor production are noted for astroglia‐rich or microglia‐rich regions of rat neocortex damaged by ischemia. These observations suggest that microglia and astroglia compete for control of neuronal survival. Importantly, microglial neurotoxins might hinder the recovery of neurologic function at sites of inflammation.
Gliosis
Neocortex
Neuroglia
Cite
Citations (299)
STIMULATED MICROGLIA SUPERNATANTS INDUCED OVEREXPRESSION OF NEURONAL NITRIC OXIDE GENE IN ASTROCYTES
The glia- glia, glia-neuron interactions are very complex and have not yet been clearly understood. Microglia gain reactivity in almost every type of brain insult and by affecting astrocytes and neurons, they determine the fate of damaged brain. In the present study we aimed to see the effect of stimulated microglia on nNOS and iNOS expression of astrocytes. The microglia cultures were stimulated with zymosanA and astrocytes were treated with the medium of microglia for 48 h. The results revealed that the astrocytes treated with microglia medium expressed more nNOS and iNOS than the ones treated with normal medium.
Neuroglia
Cite
Citations (2)
Immunoreactivity for SP-40,40, a putative complement inhibitor, adhesion or protective molecule, has been examined in a variety of inflammatory CNS lesions that displayed associations between hypertrophic astrocytes and oligodendrocytes, a phenomenon previously suggested to be related to oligodendrocyte phagocytosis or protection. SP-40,40 staining was common and was predominantly limited to hypertrophic astrocytes within lesion areas and diminished beyond the lesion margin. However, there was no consistent relationship between SP-40,40 immunoreactivity and astrocytes associated with oligodendrocytes. Staining for terminal complement complex (C5b-9/SC5b-9) occurred in association with larger vessel walls and microglial cells in the most active lesions, but was never seen in hypertrophic astrocytes. No association between SP-40,40 and complement deposition could be demonstrated. Staining for tumor necrosis factor-α showed a few scattered hypertrophic astrocytes to be positive. The findings confirm the presence of these astrocyte/oligodendrocyte interactions in active CNS lesions of varied etiology (multiple sclerosis, stroke and AIDS encephalitis). SP-40,40 immunoreactivity was common to hypertrophic astrocytes regardless of their associations with oligodendrocytes but showed no colocalization with terminal complement complex. Thus, these glial interactions do not apparently involve protection against complement-mediated lysis. Furthermore, the presence of SP-40,40 in astrocytes lacking association with oligodendrocytes did not support a role for this protein functioning as an adhesion molecule in astrocyte/oligodendrocyte associations.
Cite
Citations (31)
Neuroglia
Cite
Citations (6)
Microglia are resident immune cells of the central nervous system such as brain-specific macrophages and also known to regulate the innate immune functions of astrocytes through secretory molecules. This conversation plays an important role in brain functions and homeostasis as well as in neuropathologic disease. In this study, we aimed to elucidate whether astrocytes and microglia can cross-talk to induce microglial polarization and proliferation, which can be further regulated under the brain stroke-mimic microenvironment. Microglia in mixed glial culture increased their survival and proliferation and altered to the M2 microglia, whose role was provided by CD11b-GFAP+ astrocytes by showing approximately tenfold increase in microglia cell proliferation after the astrocyte reconstitution. Furthermore, GM-CSF stimulated microglial proliferation approximately tenfold and induced to CCR7+ M1 microglia, whose phenotype could be suppressed by anti-inflammatory cytokines such as IL-4, IL-10, and Substance-P. Also, astrocyte in the microglia co-culture revealed A2 phenotype, which could be activated to A1 astrocyte by TNFα and IFNγ under the stroke-mimic condition. Altogether, astrocyte in the mixed glial culture stimulated the microglia proliferation and M2 polarization possibly through its acquisition of A2 phenotype, both of which could be converted to M1 microglia and A1 astrocytes under the inflammatory stroke-mimic environment. This study demonstrated that microglia and astrocyte can be polarized to M2 microglia and A2 astrocytes respectively through the cross-talk in vitro and provided a system to explore how microglia and astrocyte may behave in the inflammatory disease milieu after in vivo transplantation.
Neuroglia
Cite
Citations (1)
Aim:To explore the method of culture and purification of oligodendrocyte-type-2-astrocyte progenitor cells derived from cortex of new-born rats and identification.Methods:Mixed glial cells derived from cortex of neonate rats were cultured and oligodendrocyte-type-2-astrocyte progenitor cells were purified by modified method of shaking isolation.The purified cells were then induced to differentiation and identified by immunochemical staining.Results:oligodendrocyte-type-2-astrocyte progenitor cells exhibit double positive staining of A2B5 and Nestin,which have the potential ability to differentiate into astrocytes and oligodendrocytes.The purification of isolated cells can reach over 90%.Conclusion:High purification oligodendrocyte-type-2-astrocyte progenitor cells can be acquired by low rate shaking combined with secondary plated method,so it is a simple and high effective method for the purification of oligodendrocyte-type-2-astrocyte progenitor cells.
Nestin
Progenitor
Neuroglia
Cite
Citations (0)
Abstract: Bradykinin‐ and substance P (SP)‐stimulated second messenger studies in isolated subsets of neuroglia showed bradykinin‐stimulated synthesis of phospho‐ inositides (PI) in type‐1 astrocytes and oligodendrocytes. SP‐stimulated PI accumulation was restricted to oligoden‐ drocyte/type‐2 astrocyte progenitor cells and type‐2 astrocytes. These data were confirmed by analysis of calcium transients in single cells. In a regional study, SP‐stimulated PI accumulation in primary astrocyte cultures was restricted to white matter. We conclude that regional heterogeneity in the expression of peptide receptors in cultures of primary astrocytes arises from a restricted distribution on subsets of macroglia. SP receptors restricted on cells of the oligodendrocyte/type‐2 astrocyte type‐2 lineage in vitro, coupled with in vivo observations by others, suggests that SP receptor expression is conserved on subsets of macroglia in vitro and possibly reactive astrocytes in vivo.
Neuroglia
Cite
Citations (36)