👤 Hiroshi Nishiwaki

Agricultural or gardening activity (also known as hobby farming) is a simple strategy that may be effective for maintaining health and preventing lifestyle-related diseases. However, its preventive effect on the development of conditions associated with neurovascular aging (e.g., stroke and dementia) remains unclear. To comprehensively investigate the preventive role of regular agricultural or gardening physical activity (AGPA) in neurovascular aging and its underlying mechanisms using two approaches. We conducted an experimental study in which we assessed arterial stiffness, cognitive performance (Flanker and Stroop tests), and circulating biomarkers (e.g., plasmin-α2-plasmin inhibitor complexes, nitric oxide, brain-derived neurotrophic factor) in 12 male students (average age: 22 ± 1 years) before and after three 40-min interventions (resting, cycling, and simulated AGPA) under controlled conditions. We also conducted a cross-sectional study, in which we recruited 161 (79 in the AGPA group and 82 in the control group) hospital-based older individuals (average age: 78 ± 5 years) and assessed their history of stroke, cognitive function, and brain magnetic resonance imaging (MRI) findings. In the experimental study, simulated AGPA reduced arterial stiffness, improved executive cognitive function, and elevated circulating plasmin-α2-plasmin inhibitor complexes, nitric oxide, and brain-derived neurotrophic factor. Brain MRI-assessed cerebral white matter hyperintensities caused by reduced blood flow to brain tissue and stroke prevalence were lower, and cognitive scores (as assessed by the Hasegawa Dementia Scale-Revised) were higher in the AGPA group than in the control group. Our findings suggest that regular AGPA is associated with markers of slower neurovascular aging in older individuals. AGPA induces a combination of general physical activity-related and specific AGPA-related effects; moreover, it may offer similar or even greater benefits than physical activity alone. Therefore, habitual AGPA may serve as an effective preventive strategy for neurovascular aging. Show less

Signal transduction at the neuromuscular junction (NMJ) is compromised in a diverse array of diseases including congenital myasthenic syndromes (CMS). Germline mutations in CHRNE encoding the acetylcholine receptor (AChR) ε subunit are the most common cause of CMS. An active form of vitamin D, calcitriol, binds to vitamin D receptor (VDR) and regulates gene expressions. We found that calcitriol enhanced MuSK phosphorylation, AChR clustering, and myotube twitching in co-cultured C2C12 myotubes and NSC34 motor neurons. RNA-seq analysis of co-cultured cells showed that calcitriol increased the expressions of Rspo2, Rapsn, and Dusp6. ChIP-seq of VDR revealed that VDR binds to a region approximately 15 ​kbp upstream to Rspo2. Biallelic deletion of the VDR-binding site of Rspo2 by CRISPR/Cas9 in C2C12 myoblasts/myotubes nullified the calcitriol-mediated induction of Rspo2 expression and MuSK phosphorylation. We generated Chrne knockout (Chrne KO) mouse by CRISPR/Cas9. Intraperitoneal administration of calcitriol markedly increased the number of AChR clusters, as well as the area, the intensity, and the number of synaptophysin-positive synaptic vesicles, in Chrne KO mice. In addition, calcitriol ameliorated motor deficits and prolonged survival of Chrne KO mice. In the skeletal muscle, calcitriol increased the gene expressions of Rspo2, Rapsn, and Dusp6. We propose that calcitriol is a potential therapeutic agent for CMS and other diseases with defective neuromuscular signal transmission. Show less

The Wnt signaling pathway is essential for development and organogenesis. Wnt signaling stabilizes beta-catenin, which accumulates in the cytoplasm, binds to 1-cell factor (TCF; also known as lymphocyte enhancer-binding factor, LEF) and then upregulates downstream genes. Mutations in CTNNB1 (encoding beta-catenin) or APC (adenomatous polyposis coli) have been reported in human neoplasms including colon cancers and hepatocellular carcinomas (HCCs). Because HCC5 tend to show accumulation of beta-catenin more often than mutations in CTNNB1, we looked for mutations in AXIN1, encoding a key factor for Wnt signaling, in 6 HCC cell lines and 100 primary HCC5. Among the 4 cell lines and 87 HCC5 in which we did not detect CTNNB1 mutations, we identified AXIN1 mutations in 3 cell lines and 6 mutations in 5 of the primary HCCs. In cell lines containing mutations in either gene, we observed increased DNA binding of TCF associated with beta-catenin in nuclei. Adenovirus mediated gene transfer of wild-type AXINI induced apoptosis in hepatocellular and colorectal cancer cells that had accumulated beta-catenin as a consequence of either APC, CTNNB1 or AXIN1 mutation, suggesting that axin may be an effective therapeutic molecule for suppressing growth of hepatocellular and colorectal cancers. Show less