Abscisic acid-mediated sugar responses are essential for vegetative desiccation tolerance in the liverwort Marchantia polymorpha.

Low-molecular-weight sugars serve as protectants for cellular membranes and macromolecules under the condition of dehydration caused by environmental stress such as desiccation and freezing. These sugars also affect plant growth and development by provoking internal signaling pathways. We previously showed that both sugars and the stress hormone abscisic acid (ABA) enhance desiccation tolerance of gemma, a dormant propagule of the liverwort Marchantia polymorpha. To determine the role of ABA in sugar responses in liverworts, we generated genome-editing lines of M. polymorpha ABA DEFICIENT 1 (MpABA1) encoding zeaxanthin epoxidase, which catalyzes the initial reaction toward ABA biosynthesis. The generated Mpaba1 lines that accumulated only a trace amount of endogenous ABA showed reduced desiccation tolerance and reduced sugar responses. RNA-seq analysis of sucrose-treated gemmalings of M. polymorpha revealed that expression of a large part of sucrose-induced genes was reduced in Mpaba1 compared to the wild-type. Furthermore, Mpaba1 accumulated smaller amounts of low-molecular-weight sugars in tissues upon sucrose treatment than the wild-type, with reduced expression of genes for sucrose synthesis, sugar transporters, and starch-catabolizing enzymes. These results indicate that endogenous ABA plays a role in the regulation of the positive feedback loop for sugar-induced sugar accumulation in liverworts, enabling the tissue to have desiccation tolerance.

Regional disparities in Dementia-free Life Expectancy in Japan: An ecological study, using the Japanese long-term care insurance claims database.

BACKGROUND: The number of people with dementia increases in an aging society; therefore, promoting policies for dementia throughout the community is crucial to creating a dementia-friendly society. Understanding the status of older adults with dementia in each region of Japan will be a helpful indicator. We calculated Dementia-free Life Expectancy and aimed to examine regional disparities and their associated factors. METHODS: We calculated Dementia-free Life Expectancy and Life Expectancy with Dementia for each secondary medical area in Japan based on the Degree of Independence in Daily Living for the Demented Elderly, using data extracted from the Japanese long-term care insurance claims database. We then conducted a partial least squares regression analysis, the objective variables being Dementia-free Life Expectancy and Life Expectancy with Dementia for both sexes at age 65, and explanatory regional-level variables included demographic, socioeconomic, and healthcare resources variables. RESULTS: The mean estimated regional-level Dementia-free Life Expectancy at age 65 was 17.33 years (95% confidence interval [CI] 17.27-17.38) for males and 20.05 years (95% CI 19.99-20.11) for females. Three latent components identified by partial least squares regression analysis represented urbanicity, socioeconomic conditions, and health services-related factors of the secondary medical areas. The second component explained the most variation in Dementia-free Life Expectancy of the three, indicating that higher socioeconomic status was associated with longer Dementia-free Life Expectancy. CONCLUSIONS: There were regional disparities in secondary medical area level Dementia-free Life Expectancy. Our results suggest that socioeconomic conditions are more related to Dementia-free Life Expectancy than urbanicity and health services-related factors.

Mechanosensitive modulation of peristaltic contractions in the mouse renal pelvis.

The renal pelvis develops spontaneous phasic contractions (SPCs) that underlie pyeloureteric peristalsis. Increased urine flow into the renal pelvis mechanically stimulates the contractile machinery within the renal pelvis to facilitate the propagation of peristalsis. Here, the effects of mechanostimulation of the pelvicalyceal junction (PCJ), where SPCs originate from, on the properties of SPCs were investigated. Using the wire myograph, isometric tension changes in tubular preparations of mouse renal pelvis with calyces were circumferentially measured, while mechanostimuli were applied to the PCJ. Immunohistochemistry and intracellular Ca2+ imaging were performed, respectively, to investigate the distribution and functional roles of mechanosensitive TRPV4 channels in the renal pelvis. SPCs periodically originated from PCJ and propagated distally. Mechanostimulation of the PCJ reduced the frequency of SPCs by about 60%, while almost quadrupling their amplitude. Capsaicin (100 nM), an agonist of TRPV1 channels, or calcitonin gene-related peptide (CGRP) (30 nM) also slowed and enlarged SPCs. A prolonged pre-exposure to capsaicin or BIBN4096 (1 µM), a CGRP receptor antagonist, inhibited the mechanostimulation-induced reduction in the SPC frequency, but did not block the increase in SPC amplitude. TRPV4 immunoreactivity was expressed in both atypical (ASMCs) and typical smooth muscle cells (TSMCs). GSK1016790A (100 nM), a TRPV4 agonist, enlarged SPCs independently of TRPV1 or CGRP without increasing the amplitude of spontaneous Ca2+ transients in TSMCs. Thus, mechanostimulation of PCJ appears to activate TRPV1-expressing sensory nerves, releasing CGRP that predominantly reduce the SPC frequency. Activation of TRPV4 may be involved in the mechanosensitive enlargement of SPCs. (247 words).