キドウ ジョウヒ サイボウ ノ ブンカ セイギョ ニ カンスル ブンシ セイブツガクテキ ケンキュウ

Respiratory diseases, such as asthma and chronic obstructive lung diseases, are serious global health problems. People of all ages in countries throughout the world are affected by these chronic airway disorders that can be severe and sometimes fatal. The prevalence of respiratory diseases is increasing everywhere, especially not among children. At respiratory diseases, there are severe pathophysiological changes including fibrosis, hyperplasia and hypertrophy etc. Some of these changes may be irreversible, leading to the worse. To elucidate mechanisms of these changes, I focused on two typical changes, hyperplasia of submucosal gland and tissue remodeling, and examined that transcription factors participate in these changes

Polysulfide protects midbrain dopaminergic neurons from MPP+-induced degeneration via enhancement of glutathione biosynthesis

Polysulfides are endogenous sulfur-containing molecular species that may regulate various cellular functions. Here we examined the effect of polysulfides exogenously applied to rat midbrain slice cultures, to address their potential neuroprotective actions. Na2S3 at concentrations of 10 μM or higher prevented 1-methyl-4-phenylpyridinium (MPP+)-induced loss of dopaminergic neurons. Na2S4 at 10 μM also protected dopaminergic neurons from MPP+ cytotoxicity, whereas Na2S and Na2S2 at the same concentration had no significant effect. We also found that Na2S3 (10 μM) prevented MPP+-induced increase in intracellular reactive oxygen species as detected by 2′,7′-dichlorofluorescein fluorescence. In addition, the protective effect of Na2S3 was abolished by l-buthionine sulfoximine, an inhibitor of glutathione synthesis. In cellular models of neurons (SH-SY5Y cells) and glial cells (C6 cells), Na2S3 (30 and 100 μM) increased expression of mRNAs encoding the subunits of glutamate cysteine ligase, the rate-limiting enzyme for glutathione biosynthesis. Consistently, the cellular content of total glutathione was increased by Na2S3, and the effect was more prominent in SH-SY5Y cells than in C6 cells. These results suggest that polysulfides are efficient neuroprotectants superior to monosulfur species such as H2S and HS−, and that the neuroprotective effect of polysulfides is mediated by upregulation of glutathione biosynthesis. Keywords: Parkinson disease, Dopamine neuron, Oxidative stress, Neuroprotection, Reactive sulfur specie

Na+, K+-ATPase inhibition induces neuronal cell death in rat hippocampal slice cultures: Association with GLAST and glial cell abnormalities

Na+, K+-ATPase is a highly expressed membrane protein. Dysfunction of Na+, K+-ATPase has been implicated in the pathophysiology of several neurodegenerative and psychiatric disorders, however, the underlying mechanism of neuronal cell death resulting from Na+, K+-ATPase dysfunction is poorly understood. Here, we investigated the mechanism of neurotoxicity due to Na+, K+-ATPase inhibition using rat organotypic hippocampal slice cultures. Treatment with ouabain, a Na+, K+-ATPase inhibitor, increased the ratio of propidium iodide-positive cells among NeuN-positive cells in the hippocampal CA1 region, which was prevented by MK-801 and d-AP5, specific blockers of the N-methyl-d-aspartate (NMDA) receptor. EGTA, a Ca2+-chelating agent, also protected neurons from ouabain-induced injury. We observed that astrocytes expressed the glutamate aspartate transporter (GLAST), and ouabain changed the immunoreactive area of GFAP-positive astrocytes as well as GLAST. We also observed that ouabain increased the number of Iba1-positive microglial cells in a time-dependent manner. Furthermore, lithium carbonate, a mood-stabilizing drug, protected hippocampal neurons and reduced disturbances of astrocytes and microglia after ouabain treatment. Notably, lithium carbonate improved ouabain-induced decreases in GLAST intensity in astrocytes. These results suggest that glial cell abnormalities resulting in excessive extracellular concentrations of glutamate contribute to neurotoxicity due to Na+, K+-ATPase dysfunction in the hippocampal CA1 region. Keywords: Glutamate aspartate transporter (GLAST), Hippocampus, Na+, K+-ATPase, Neuronal cell death, N-methyl-d-aspartate (NMDA) recepto

Depolarizing stimuli cause persistent and selective loss of orexin in rat hypothalamic slice culture

A hypothalamic neuropeptide orexin (hypocretin) is a critical regulator of physiological processes including sleep/wakefulness and feeding. Using organotypic slice culture of rat hypothalamus, we found that exposure to elevated extracellular concentration of K+ (+10-30 mM) for 24-72 h led to a substantial decrease in the number of neurons immunoreactive for orexin and a co-existing neuropeptide dynorphin-A. In contrast, the same treatment affected neither the number of melanin-concentrating hormone-immunoreactive neurons nor the number of total neurons. A substantial decrease of orexin-immunoreactive neurons was also induced by 72 h treatment with 1-10 μM veratridine, a Na+ channel activator. The effect of elevated K+ was only partially reversible, and that of veratridine was virtually irreversible, although the decrease in orexin immunoreactivity was not associated with signs of cell damage assessed by propidium iodide uptake and Hoechst 33342 nuclear staining. In addition, the level of preproorexin mRNA did not decrease during treatment with elevated K+ or veratridine. After treatment with elevated K+ and veratridine, c-Fos immunoreactivity appeared in orexin-immunoreactive neurons but not in melanin-concentrating hormone-immunoreactive neurons, suggesting selective excitation of orexin neurons. However, the amount of orexin released extracellularly was paradoxically decreased by treatment with elevated K+ and veratridine. Overall, these characteristics of orexin neurons may be taken into consideration to understand the behaviors of these neurons under physiological and pathophysiological conditions

MRI-based analysis of intracerebral hemorrhage in mice reveals relationship between hematoma expansion and the severity of symptoms.

Intracerebral hemorrhage (ICH) is featured by poor prognosis such as high mortality rate and severe neurological dysfunction. In humans, several valuables including hematoma volume and ventricular expansion of hemorrhage are known to correlate with the extent of mortality and neurological dysfunction. However, relationship between hematoma conditions and the severity of symptoms in animal ICH models has not been clarified. Here we addressed this issue by using 7-tesla magnetic resonance imaging (MRI) on collagenase-induced ICH model in mice. We found that the mortality rate and the performance in behavioral tests did not correlate well with the volume of hematoma. In contrast, when hemorrhage invaded the internal capsule, mice exhibited high mortality and showed poor sensorimotor performance. High mortality rate and poor performance in behavioral tests were also observed when hemorrhage invaded the lateral ventricle, although worsened symptoms associated with ventricular hemorrhage were apparent only during early phase of the disease. These results clearly indicate that invasion of the internal capsule or the lateral ventricle by hematoma is a critical determinant of poor prognosis in experimental ICH model in mice as well as in human ICH patients. MRI assessment may be a powerful tool to refine investigations of pathogenic mechanisms and evaluations of drug effects in animal models of ICH

Invasion of hematoma into LV worsens mortality and initial neurological dysfunction.

<p>(A) Representative images of T2-MRI scans (+1.1, +0.1, −0.9 and −1.9 mm relative to bregma) in a non-LV ICH mouse and an LV ICH mouse at 6 h after induction of ICH. Boundary between hematoma and surrounding tissues is indicated by solid white line. (B) Close-up view of MRI images showing invasion of hematoma into LV in an LV ICH mouse. Arrows indicate LV. (C–F) LV ICH mice (<i>n</i> = 14 at 6 h) and non-LV ICH mice (<i>n</i> = 27 at 6 h) were compared by hematoma volume (C), survival rate (D), hindlimb fault rate in the beam-walking test (E) and performance score in the modified limb-placing test (F). Data sets consist of values derived from all mice surviving at each time point. ** <i>P</i><0.01, *** <i>P</i><0.001 versus non-LV ICH group.</p