👤 Atsumu Yuki

The apolipoprotein E ε4 (APOE ε4) allele, a major genetic risk factor for Alzheimer's disease, is associated with early atrophy in the precuneus and posterior cingulate cortex. Whether physical activity can mitigate this atrophy in high-risk APOE ε4 carriers remains unclear. This study aimed to determine whether physical activity can reduce such neurodegenerative changes in older adults carrying this allele. This 10-year longitudinal study included 295 community-dwelling older adults (154 men and 141 women; age ≥65 years). Baseline physical activity was measured using accelerometers and analyzed according to activity intensity. Participants were categorized as APOE ε4 carriers or non-carriers. Volumes of the precuneus and posterior cingulate cortex were assessed using longitudinal magnetic resonance imaging. Sex-stratified linear mixed models examined the interaction between physical activity and APOE ε4 status on brain volume changes, adjusting for relevant covariates. The moderate-to-vigorous physical activity (MVPA) × APOE ε4 × year effect in women's left precuneus was significant unadjusted but not after false discovery rate (FDR; 16 models) and exploratory. Left precuneus volume declined significantly over 10 years regardless of MVPA level or APOE ε4 genotype (each p < 0.0001). However, among APOE ε4 carriers, greater time spent in MVPA slowed the rate of volume decline. No similar effect was observed in men. Higher habitual MVPA may be associated with slower left precuneus decline in APOE ε4-positive women. As this exploratory three‑way effect was FDR‑nonsignificant, targeted replication is needed to clarify the role of everyday activity in genetically vulnerable groups. Show less

Integrin αLβ2 (CD11a/CD18, CD11a) is a critical leukocyte adhesion molecule in leukocyte arrest and immunological synapse formation. However, its role in the bone marrow has not been investigated in depth. Here we showed that CD11a was expressed on all subsets of hematopoietic stem and progenitor cells (HPSCs). CD11a deficiency enhanced HSPCs activity under lipopolysaccharide (LPS) stimulation as demonstrated by a higher HSPC cell count along with an increase in cell proliferation. However, our mixed chimera experiment did not support that this phenotype was driven in a cell-intrinsic manner. Rather we found that the production of IL-27, a major cytokine that drives HSPC proliferation, was significantly upregulated both Show less

Peyer's patches (PPs), which are covered by specialized follicle-associated epithelium (FAE) including M cells, play a central role in immune induction in the gastrointestinal tract. This study is to investigate a new molecule to characterize PPs. We generated a monoclonal antibody (mAb 10-15-3-3) that specifically reacts to the epithelium of PPs and isolated lymphoid follicles. Target antigen was analyzed by immunoprecipitation and mass spectrometry. Localization and expression of target antigen were evaluated by immunofluorescence, in situ hybridization and real-time PCR. Immunoprecipitation and mass spectrometry revealed that mAb 10-15-3-3 recognized apolipoprotein A-IV (ApoA-IV), a well-known lipid transporter; this finding was confirmed by the specific reactivity of mAb 10-15-3-3 to cells transfected with the murine ApoA-IV gene. Immunofluorescence using mAb 10-15-3-3 showed intestinal localization of ApoA-IV, in which strong expression of the ApoA-IV protein occurred throughout the entire intestinal epithelium during developing period before weaning but was restricted to the FAE in adult mice. In support of these findings, in situ hybridization showed strong expression of the ApoA-IV gene throughout the entire intestinal epithelium during developing period before weaning, but this expression was restricted to the FAE predominantly and the tips of villi to a lesser extent in adult mice. Deficiency of ApoA-IV had no effect on the organogenesis of PP in mice. Our current results reveal ApoA-IV as a novel FAE-specific marker especially in the upper small intestine of adult mice. Show less