👤 Katsuko Sudo

The mutual effects of different activity intensities in daily life, such as sedentary behavior (SB) and physical activity (PA), on dementia onset are not yet fully understood. The purpose of this study was to examine the association between replacing SB with PA and the risk of dementia in older adults by using the isotemporal substitution (IS) model. Prospective cohort study. Community-dwelling older adults living without dementia in Takahama, were enrolled, interviewed, and physically examined. Follow-up data were collected from the Japanese Public Health Insurance and/or Long-Term Care Insurance system databases during follow-up. SB and PA data [light-intensity PA (LPA) and moderate-to-vigorous PA (MVPA)] were measured using a triaxial accelerometer for 14 days, and the average daily time for SB and PA was calculated in 10-minute increments. Participants were followed up monthly for new-onset dementia over 5 years. Cox proportional-hazards regression analysis was performed by using IS to estimate the effect of replacing one activity with another on the dementia onset. We included 1664 participants (mean ± standard deviation age, 73.1 ± 5.9 years) in this study. Over 5 years, 128 of 1664 participants developed dementia. Replacing 10 min/d of SB with LPA (hazard ratio, 0.86; 95% CI, 0.75-0.99) or MVPA (0.84; 0.74-0.96) was associated with a lower risk of dementia. Replacing 10 minutes of SB with LPA or MVPA was associated with a lower risk of dementia. Feasible behavioral changes in daily life may lead to a healthy life expectancy. Show less

Epstein-Barr virus-induced gene 3 (EBI3) is a subunit common to IL-27, IL-35, and IL-39. Here, we explore an intracellular role of EBI3 that is independent of its function in cytokines. EBI3-deficient naive CD4+ T cells had reduced IFN-γ production and failed to induce T cell-dependent colitis in mice. Similarly reduced IFN-γ production was observed in vitro in EBI3-deficient CD4+ T cells differentiated under pathogenic Th17 polarizing conditions with IL-23. This is because the induction of expression of one of the IL-23 receptor (IL-23R) subunits, IL-23Rα, but not another IL-23R subunit, IL-12Rβ1, was selectively decreased at the protein level, but not the mRNA level. EBI3 augmented IL-23Rα expression via binding to the chaperone molecule calnexin and to IL-23Rα in a peptide-dependent manner, but not a glycan-dependent manner. Indeed, EBI3 failed to augment IL-23Rα expression in the absence of endogenous calnexin. Moreover, EBI3 poorly augmented the expression of G149R, an IL-23Rα variant that protects against the development of human colitis, because binding of EBI3 to the variant was reduced. Taken together with the result that EBI3 expression is inducible in T cells, the present results suggest that EBI3 plays a critical role in augmenting IL-23Rα protein expression via calnexin under inflammatory conditions. Show less