Project description:Objective: Connexins are known to compose gap junctions by a pair of hemichannels connected in a head to head configuration. Each hemichannel is composed by hexameric cluster of connexins. There are 20 members of connexins known as connexin family in mice, and are expressed on each cell surface in different fashion. Connexin 30 (Cx30) is mainly expressed on the surface of oligodendroglia and astrocyte in central nervous system (CNS), but little is known about the functional relevance in neuroinflammatory diseases. To elucidate the role of Cx30 in the pathogenesis of neuroinflammatory disease, we induced experimental autoimmune encephalomyelitis (EAE) on Cx30 knock-out (Cx30-KO) mice and analyzed the clinical and neuropathological findings with wild-type control. Methods: C57BL/6J and Cx30-KO mice > 12 weeks of age were used in this study (N > 3 in each group). EAE was induced by immunization of mice with MOG35-55 peptide emulsified in CFA at a dose of 200 μg per mouse, followed by the administration of pertussis toxin (500 ng per mouse) on days 0 and 2. Mice were sacrificed and brain, spinal cord, spleen, and optic nerve were harvested for immunohistochemical analyses at the acute and chronic phases of EAE. Mice with EAE were scored as follows: 0, no disease; 1, limp tail; 2, abnormal gait and hind limb weakness (shaking); 2.5, paralysis of one hind limb; 3, paralysis of two hind limb; 3.5, ascending paralysis (able to move around); 4, tetraplegia; and 5, moribund (death). At the onset and chronic stage of EAE, mononuclear cells were isolated and analyzed by flow cytometry to check the distinct characteristics of cellular populations in inflamed CNS lesions. Results: Initial screening of immunohistological difference revealed basic activation of microglial cells in naïve Cx30-KO mice without any behavioral phenotype. Clinical signs of EAE were ameliorated in the Cx30-KO mice than in the control group mainly during the chronic phase of disease course. Immunohistochemical analyses of the fourth lumbar segment, brain and optic nerve revealed increased number of microglia in the Cx30-KO mice. Flow cytometric analysis also confirmed the findings. In contrast, there were no significant change in astroglial or oligodendroglial phenotype. Conclusion: Microglial activation appears to be the key factor in the Cx30-KO mice EAE with alleviation of chronic disease scores. Unexpectedly, microglia were already activated in naïve CNS, indicating protective phenotypic change of microglia in Cx30-KO mice.
Project description:Objective: Connexins are known to compose gap junctions by a pair of hemichannels connected in a head to head configuration. Each hemichannel is composed by hexameric cluster of connexins. There are 20 members of connexins known as connexin family in mice, and are expressed on each cell surface in different fashion. Connexin 30 (Cx30) is mainly expressed on the surface of oligodendroglia and astrocyte in central nervous system (CNS), but little is known about the functional relevance in neuroinflammatory diseases. To elucidate the role of Cx30 in the pathogenesis of neuroinflammatory disease, we induced experimental autoimmune encephalomyelitis (EAE) on Cx30 knock-out (Cx30-KO) mice and analyzed the clinical and neuropathological findings with wild-type control. Methods: C57BL/6J and Cx30-KO mice > 12 weeks of age were used in this study (N > 3 in each group). EAE was induced by immunization of mice with MOG35-55 peptide emulsified in CFA at a dose of 200 μg per mouse, followed by the administration of pertussis toxin (500 ng per mouse) on days 0 and 2. Mice were sacrificed and brain, spinal cord, spleen, and optic nerve were harvested for immunohistochemical analyses at the acute and chronic phases of EAE. Mice with EAE were scored as follows: 0, no disease; 1, limp tail; 2, abnormal gait and hind limb weakness (shaking); 2.5, paralysis of one hind limb; 3, paralysis of two hind limb; 3.5, ascending paralysis (able to move around); 4, tetraplegia; and 5, moribund (death). At the onset and chronic stage of EAE, mononuclear cells were isolated and analyzed by flow cytometry to check the distinct characteristics of cellular populations in inflamed CNS lesions. Results: Initial screening of immunohistological difference revealed basic activation of microglial cells in naïve Cx30-KO mice without any behavioral phenotype. Clinical signs of EAE were ameliorated in the Cx30-KO mice than in the control group mainly during the chronic phase of disease course. Immunohistochemical analyses of the fourth lumbar segment, brain and optic nerve revealed increased number of microglia in the Cx30-KO mice. Flow cytometric analysis also confirmed the findings. In contrast, there were no significant change in astroglial or oligodendroglial phenotype. Conclusion: Microglial activation appears to be the key factor in the Cx30-KO mice EAE with alleviation of chronic disease scores. Unexpectedly, microglia were already activated in naïve CNS, indicating protective phenotypic change of microglia in Cx30-KO mice.
Project description:We use microarray analysis to compare the expression profiles of glioma-associated microglia/macrophages and naive control cells. Samples were generated from CD11b+ MACS-isolated cells from naïve and GL261-implanted C57BL/6 mouse brains.
Project description:Gap junctions are arrays of intercellular channels formed by two hemichannels docked end-to-end. Each hemichannel is a hexamer containing the same or different connexin (Cx) isoform. While homomeric Cxs forms have been largely described functionally and structurally, lesser is known about heteromeric Cx channels. To unveil properties of heteromeric Cx channels is challenging considering the high number of potential subunit arrangements and stoichiometries, even for only combining two Cx isoforms. We engineered an HA tag onto Cx26 or Cx30 subunits and imaged hemichannels that were liganded by Fab-epitope antibody fragments. For Cx26-HA/Cx30 or Cx26/Cx30-HA heteromeric channels, the Fab-HA binding distribution followed a binomial distribution with a maximum of 3 Fab-HA bound. Furthermore, imaged Cx26/Cx30-HA triple liganded by Fab-HA showed multiple arrangements which can be derived from the law of total probabilities. Our results indicate a dominant subunit stoichiometry of 3Cx26:3Cx30 with the most abundant subunit arrangement of Cx26-Cx26-Cx30-Cx26-Cx30-Cx30.
Project description:Connexin (Cx)30, which forms gap junction interconnecting astrocytes, regulates cell adhesion and migration and modulates glutamate transport. The expression levels of Cx30 are known to be upregulated on the activated astroglia at CNS inflammation lesion, including mutant-SOD1 transgenic ALS model mice spinal cord lesion. We aimed to clarify the role of Cx30 in mSOD1-transgenic mice. Cx30 was highly expressed in the pre-clinical stage of mSOD1-Tg mice. Cx30-knockout mSOD1 mice showed a delayed onset and tended to extend the survival period (log-rank, p = 0.09). At the progressive and end stages, anterior horn cells were more preserved in Cx30-knockout mSOD1 mice. Additionally, dorsal horn cells were kept more in Cx30-knockout mSOD1 mice at all stages. In the lesion of Cx30-knockout mSOD1 mice, GFAP and C3 positive inflammatory astroglia were decreased. Further, in Cx30-knockout mSOD1 mice, the amount of NOS2 protein at the end stage and the amount of Cx43 protein at the pre-clinical stage were smaller than in mSOD1 mice. These findings indicated reduced expression of astroglial Cx30 in the early stage of ALS model mice protects neurons by the attenuation of glial inflammation.