Treatment of intermittent hypoxia increases phosphorylated tau in the hippocampus via biological processes common to aging

Sleep-disordered breathing produces cognitive impairments, and is possibly associated with Alzheimer disease (AD). Intermittent hypoxia treatment (IHT), an experimental model for sleep-disordered breathing, results in cognitive impairments in animals via unknown mechanisms. Here, we exposed mice to IHT protocols, and performed biochemical analyses and microarray analyses regarding their hippocampal samples. In particular, we performed gene ontology (GO)-based microarray analysis to elucidate effects of IHT on hippocampal functioning, which were compared with the effects of various previously-reported experimental conditions on that (ref. Gene Expression Omnibus, The National Center for Biotechnology Information). Our microarray analyses revealed that IHT and aging shared alterations in some common GO, which were also observed with kainic acid treatment, Dicer ablation, or moderate glutamate excess. Mapping the altered genes using the Kyoto Encyclopedia of Genes and Genomes PATHWAY database indicated that IHT and aging affected several pathways including “MAPK signaling pathway”, “PI3K-Akt signaling pathway”, and “glutamatergic synapse”. Consistent with the gene analyses, in vivo analyses revealed that IHT increased phosphorylated tau, reflecting an imbalance of kinases and/or phosphatases, and reduced proteins relevant to glutamatergic synapses. In addition, IHT increased phosphorylated p70 S6 kinase, indicating involvement of the mammalian target of rapamycin signaling pathway. Furthermore, IHT mice demonstrated hyperactivity in Y-maze tests, which was also observed in AD models. We obtained important data or something from the massive amount of microarray data, and confirmed the validity by in vivo analyses: the IHT-induced cognitive impairment may be partially explained by the fact that IHT increases phosphorylated tau via biological processes common to aging. Moreover, as aging is a major risk factor for AD, IHT is a novel model for investigating the pathological processes contributing to AD onset.

The Effects of a Selective CK2 Inhibitor on Anti-glomerular Basement Membrane Glomerulonephritis in Rats

Protein kinase CK2 ("casein kinase II") is a protein serine/threonine kinase that plays critical roles in biological processes such as cell growth, cell cycle progression, and apoptosis. So far, we have identified that one catalytic isozyme of CK2, CK2α, is over-expressed in the kidney during the progression of glomerulonephritis (GN). Moreover, we have shown that in vivo inhibition of CK2 by administration of CK2 inhibitors was effective in the treatment of experimental GN. Hence the development of potent CK2 inhibitors should be considered in therapeutic strategies for GN. In the present study we identified compound 13, a pyrazine derivative, as a potent CK2 inhibitor. By performing enzyme kinetics analysis in vitro, we characterized the inhibition of compound 13 toward each CK2 catalytic isozyme. Furthermore, in vivo, we demonstrated that compound 13 is effective in attenuating proteinuria, decreasing the enhanced level of blood urea nitrogen and serum creatinine, and ameliorating glomerular crescent formation in an experimental GN rat model. On the other hand, cellular apoptosis was detected in the rat testis following administration of compound 13. This study provides clues for new strategies for developing applicable compounds into CK2-targeted GN treatments.