Differential expression of nuclear lamin subtypes in the neural cells of the adult rat cerebral cortex

Lamins are type V intermediate filament proteins that are located beneath the inner nuclear membrane. In mammalian somatic cells, LMNB1 and LMNB2 encode somatic lamins B1 and B2, respectively, and the LMNA gene is alternatively spliced to generate somatic lamins A and C. Mutations in lamin genes have been linked to many human hereditary diseases, including neurodegenerative disorders. Knowledge about lamins in the nervous system has been accumulated recently, but a precise analysis of lamin subtypes in glial cells has not yet been reported. In this study we investigated the composition of lamin subtypes in neurons, astrocytes, oligodendrocyte-lineage cells, and microglia in the adult rat cerebral cortex using an immunohistochemical staining method. Lamin A was not observed in neurons and glial cells. Lamin C was observed in astrocytes, mature oligodendrocytes and neurons, but not observed in oligodendrocyte progenitor cells. Microglia also did not stain positive for lamin C which differed from macrophages, with lamin C positive. Lamin B1 and B2 were observed in all glial cells and neurons. Lamin B1 was intensely positive in oligodendrocyte progenitor cells compared with other glial cells and neurons. Lamin B2 was weakly positive in all glial cells compared to neurons. Our current study might provide useful information to reveal how the onset mechanisms of human neurodegenerative diseases are associated with mutations in genes for nuclear lamin proteins

Involvement of CD11b+ GR-1low cells in autoimmune disorder in MRL-Faslpr mouse

金沢大学医薬保健研究域医学系Objective: Myeloid-derived suppressor cells (MDSCs) have been identified as immunosuppressive cells in tumor-related inflammation. However, the pathogenesis of MDSCs for autoimmune disease has not been investigated as yet. The aim of this study was to address whether MDSCs contribute to autoimmune organ injury in lupus-prone mice. Methods: MDSCs were analyzed by flow cytometric staining of CD11b+ GR-1+ in MRL-Faslpr mice. CD4+ T-cell proliferation assay was performed by coculture with CD11b+ GR-1+ splenocytes. The percentage of immunosuppressive cells was examined during disease progression. Expression of chemokine receptor on immunosuppressive cells was analyzed, and chemotaxis assay was performed. Results: CD11b+ GR-1low cells had a suppressive effect on CD4+ T-cell proliferation, which was restored by an arginase-1 inhibitor. CD11b+ GR-1low cells increased in percentage during disease progression in kidney and blood. The number of migrated CD11b+ GR-1low cells increased in the presence of monocyte chemoattractant protein-1/CCL2. Conclusion: We assessed the involvement of CD11b+ GR-1low cells in autoimmune disorder in MRL-Faslpr mice. These cells regulate immunological responses via CCL2/CCR2 signaling. The regulation of immunosuppressive monocytes may provide novel therapeutic strategy for organ damage in autoimmune diseases. © 2010 Japanese Society of Nephrology.

Cross sections for nuclide production in proton- and deuteron-induced reactions on 93

Isotopic production cross sections were measured for proton- and deuteron-induced reactions on 93Nb by means of the inverse kinematics method at RIKEN Radioactive Isotope Beam Factory. The measured production cross sections of residual nuclei in the reaction 93Nb + p at 113 MeV/u were compared with previous data measured by the conventional activation method in the proton energy range between 46 and 249 MeV. The present inverse kinematics data of four reaction products (90Mo, 90Nb, 88Y, and 86Y) were in good agreement with the data of activation measurement. Also, the model calculations with PHITS describing the intra-nuclear cascade and evaporation processes generally well reproduced the measured isotopic production cross sections

Differential responses of endogenous adult mouse neural precursors to excess neuronal excitation

Adult neurogenesis in the subgranular zone of the hippocampus (SGZ) is enhanced by excess as well as mild neuronal excitation, such as chemoconvulsant‐induced brief seizures. Because most studies of neurogenesis after seizures have focused on the SGZ, the threshold of neuronal excitation required to enhance neurogenesis in the subventricular zone (SVZ) is not clear. Therefore, we examined the responses of SVZ precursors to brief generalized clonic seizures induced by a single administration of the chemoconvulsant pentylenetetrazole (PTZ). Cell cycle progression of precursors was analysed by systemic administration of thymidine analogues. We found that brief seizures immediately resulted in cell cycle retardation in the SVZ. However, the same effect was not seen in the SGZ. This initial cell cycle retardation in the SVZ was followed by enhanced cell cycle re‐entry after the first round of mitosis, leading to precursor pool expansion, but the cell cycle retardation and expansion of the precursor pool were transient. Cell cycle progression in the PTZ‐treated group returned to normal after one cell cycle. The numbers of precursors in the SVZ and new neurons in the olfactory bulb, which are descendants of SVZ precursors, were not significantly different from those in control mice more than 2 days after seizures. Because similar effects were observed following electroconvulsive seizures, these responses are likely to be general effects of brief seizures. These results suggest that neurogenesis in the SVZ is more tightly regulated and requires stronger stimuli to be modified than that in the SGZ

Differential expression of nuclear lamin subtypes in the neural cells of the adult rat cerebral cortex

Lamins are type V intermediate filament proteins that are located beneath the inner nuclear membrane. In mammalian somatic cells, LMNB1 and LMNB2 encode somatic lamins B1 and B2, respectively, and the LMNA gene is alternatively spliced to generate somatic lamins A and C.Mutations in lamin genes have been linked to many human hereditary diseases, including neurodegenerative disorders. Knowledge about lamins in the nervous system has been accumulated recently, but a precise analysis of lamin subtypes in glial cells has not yet been reported. In this study we investigated the composition of lamin subtypes in neurons, astrocytes, oligodendrocyte-lineage cells, and microglia in the adult rat cerebral cortex using an immunohistochemical staining method. Lamin A was not observed in neurons and glial cells. Lamin C was observed in astrocytes, mature oligodendrocytes and neurons, but not observed in oligodendrocyte progenitor cells. Microglia also did not stain positive for lamin C which differed from macrophages, with lamin C positive. Lamin B1 and B2 were observed in all glial cells and neurons. Lamin B1 was intensely positive in oligodendrocyte progenitor cells compared with other glial cells and neurons. Lamin B2 was weakly positive in all glial cells compared to neurons. Our current study might provide useful information to reveal how the onset mechanisms of human neurodegenerative diseases are associated with mutations in genes for nuclear lamin proteins. Keywords: Lamins, Neurons, Glial cells, Adult rat, Cerebral cortex, Immunohistochemistr