Mib1 contributes to persistent directional cell migration by regulating the Ctnnd1-Rac1 pathway.

Persistent directional cell migration is involved in animal development and diseases. The small GTPase Rac1 is involved in F-actin and focal adhesion dynamics. Local Rac1 activity is required for persistent directional migration, whereas global, hyperactivated Rac1 enhances random cell migration. Therefore, precise control of Rac1 activity is important for proper directional cell migration. However, the molecular mechanism underlying the regulation of Rac1 activity in persistent directional cell migration is not fully understood. Here, we show that the ubiquitin ligase mind bomb 1 (Mib1) is involved in persistent directional cell migration. We found that knockdown of MIB1 led to an increase in random cell migration in HeLa cells in a wound-closure assay. Furthermore, we explored novel Mib1 substrates for cell migration and found that Mib1 ubiquitinates Ctnnd1. Mib1-mediated ubiquitination of Ctnnd1 K547 attenuated Rac1 activation in cultured cells. In addition, we found that posterior lateral line primordium cells in the zebrafish mib1ta52b mutant showed increased random migration and loss of directional F-actin-based protrusion formation. Knockdown of Ctnnd1 partially rescued posterior lateral line primordium cell migration defects in the mib1ta52b mutant. Taken together, our data suggest that Mib1 plays an important role in cell migration and that persistent directional cell migration is regulated, at least in part, by the Mib1-Ctnnd1-Rac1 pathway.

Opinions on research involving human embryo models by researchers and the general public.

Rules and ethical considerations regarding research on embryo models have been debated across numerous countries. In this paper, we provide insights from our attitude survey conducted among Japanese researchers, including members of the Japanese Society for Regenerative Medicine, and among the general public residing in Japan, the US, the UK, Canada, and Australia. Our survey revealed that many researchers expressed the need for clear guidelines for embryo model research. Furthermore, a minority but significant portion of the general public in each country expressed opposition to research on embryo models but did not oppose research involving real embryos.

General public's understanding of rare diseases and their opinions on medical resource allocation in Japan: a cross-sectional study.

BACKGROUND: Rare diseases (RDs) may impose a considerable financial burden on patients and their families. Public acceptance is essential to ensure sustainable public systems supporting RDs, especially in countries with universal healthcare coverage, such as Japan. This study aimed to explore the public's understanding of RDs and identify crucial factors associated with the public acceptance of prioritizing financial support for RDs in Japan. METHODS: An online questionnaire was sent to 131,220 Japanese residents aged 20-69 years. The items included in the questionnaire were general interest in medical science and medical care, general knowledge regarding RDs and health care systems, opinions on the cost of medical care, opinions on the research and development of RDs and common diseases, and individual characteristics. RESULTS: The responses of 11,019 respondents were analyzed. Several respondents agreed to partially cover the medication cost of adult and pediatric RDs (59.5% and 66.8%, respectively) with public funding. The major reasons for agreeing were the huge financial burden imposed on patients and their families, limited available treatment options, effects of RDs on the life planning of patients, and difficulties caused by RDs in the patient's social life. Furthermore, the respondents ranked RDs (56.0%) higher than common diseases (44.0%) for government funding for research and development. The reasons for supporting government-funded research and development for RDs included the lack of treatment options for numerous RDs (34.9%) and difficulty of studying RDs owing to the small number of researchers (25.9%). The chief reasons for supporting government-funded research and development for common diseases were the large number of affected patients (59.7%) and the possibility of more treatment options becoming available through the promotion of research and development (22.1%). CONCLUSIONS: The general public considers burdens associated with daily living or finance more than the epidemiological characteristics of RD while making funding decisions, demonstrating that rarity was less prioritized. A gap appears to exist between the general public and RD experts regarding the understanding of the epidemiological characteristics of RD and its thresholds. This gap should be bridged to ensure that prioritization of financial support for RDs is accepted by the society.

Attitudes towards human fetal tissue research: Survey of researchers and the public in Japan.

Introduction: The rules for human fetal tissue (HFT) research in Japan are unclear. Methods: In this paper, we conducted a web survey to examine the attitudes of Japanese researchers (n=535) and the public (n=3,000) toward HFT research. Results: The results demonstrated that 5.8% of researchers and 18.8% of the public explicitly opposed HFT research, and 71.8% of the researchers thought that the rules for HFT research need to be clarified. Even among researchers who intended to consider conducting HFT research, 74.2% responded that the rules should be clarified. Although different from attitudes to make decisions regarding HFT donation, being non-religious and in their reproductive age among women in the public group were factors for accepting attitudes toward HFT research. Conclusion: To establish the rules, it is necessary to develop a system that can adequately protect vulnerable women who are asked to provide HFT.

Survey of Japanese researchers and the public regarding the culture of human embryos in vitro beyond 14 days.

The International Society for Stem Cell Research (ISSCR) has eliminated its prohibition on research involving the culturing of human embryos beyond 14 days within the updated 2021 guidelines. We conducted a survey of Japanese researchers working in stem cell- or embryo-related research (n = 535) and the public (n = 3,000) about their attitudes toward the 14-day rule. Among the researchers, 46.2% agreed that embryos could be cultured beyond 14 days, a result that was slightly lower among the public (37.9%). Among those that disagreed with embryo culturing beyond 14 days, 9.5% of researchers and 5.1% of the public agreed with culturing embryos within 14 days. Among the public, higher comprehension levels correlated with both agreement and disagreement with the culture of embryos beyond 14 days compared with "cannot judge." Further research and pubic discourse are necessary in order to better understand the factors informing participant decisions regarding the 14-day rule.

Deregulated Cdc6 inhibits DNA replication and suppresses Cdc7-mediated phosphorylation of Mcm2-7 complex.

Mcm2-7 is recruited to eukaryotic origins of DNA replication by origin recognition complex, Cdc6 and Cdt1 thereby licensing the origins. Cdc6 is essential for origin licensing during DNA replication and is readily destabilized from chromatin after Mcm2-7 loading. Here, we show that after origin licensing, deregulation of Cdc6 suppresses DNA replication in Xenopus egg extracts without the involvement of ATM/ATR-dependent checkpoint pathways. DNA replication is arrested specifically after chromatin binding of Cdc7, but before Cdk2-dependent pathways and deregulating Cdc6 after this step does not impair activation of origin firing or elongation. Detailed analyses revealed that Cdc6 deregulation leads to strong suppression of Cdc7-mediated hyperphosphorylation of Mcm4 and subsequent chromatin loading of Cdc45, Sld5 and DNA polymerase α. Mcm2 phosphorylation is also repressed although to a lesser extent. Remarkably, Cdc6 itself does not directly inhibit Cdc7 kinase activity towards Mcm2-4-6-7 in purified systems, rather modulates Mcm2-7 phosphorylation on chromatin context. Taken together, we propose that Cdc6 on chromatin acts as a modulator of Cdc7-mediated phosphorylation of Mcm2-7, and thus destabilization of Cdc6 from chromatin after licensing is a key event ensuring proper transition to the initiation of DNA replication.

Comparison of the 2021 International Society for Stem Cell Research (ISSCR) guidelines for "laboratory-based human stem cell research, embryo research, and related research activities" and the corresponding Japanese regulations.

This paper presents a comparison of the 2021 guidelines for stem cell research and clinical translation outlined by the International Society for Stem Cell Research (ISSCR) with the current regulations in Japan regarding the performance of such research. This paper provides a convenient English-language summary of the Japanese regulations, and illustrates the difference between the ISSCR guidelines and Japanese regulations regarding the conditions of implementation of study activities using human embryos or stem cells, for researchers outside Japan. The regulations governing the performance of research activities using human embryos or stem cells in Japan are relatively complex and comprise a range of laws and guidelines; the specific rules applied depend on the characteristics of each study. Therefore, even similar research activities may differ in terms of not only the guidelines or laws implemented, but also the procedures required. Such situations may confuse researchers.

Correction: Hasegawa et al. Impacts of Interaction of Mental Condition and Quality of Life between Donors and Recipients at Decision-Making of Preemptive and Post-Dialysis Living-Donor Kidney Transplantation. J. Pers. Med. 2021, 11, 414.

The authors wish to make the following corrections to this paper [...].

Outcomes and Safety of Very-Low-Dose Edoxaban in Frail Patients With Atrial Fibrillation in the ELDERCARE-AF Randomized Clinical Trial.

Importance: The prevalence of atrial fibrillation (AF) increases with age and is more common in frail patients. However, data are lacking on outcomes of oral anticoagulants (OACs) in very elderly patients with AF with frailty, who are ineligible for standard anticoagulant treatment. Objective: To compare very-low-dose edoxaban (15 mg daily) vs placebo across frailty status, including each of 5 frailty assessment parameters, among patients with AF involved in the ELDERCARE-AF (Edoxaban Low-Dose for Elder Care Atrial Fibrillation Patients) trial. Design, Setting, and Participants: This is a cohort study using data from ELDERCARE-AF, a multicenter, randomized, double-blind, placebo-controlled phase 3 study of Japanese patients with AF aged 80 years or older who were ineligible for OACs at doses approved for stroke prevention because of their high bleeding risks. Eligible patients were randomly assigned (1:1) to receive edoxaban or placebo. The study duration was from August 5, 2016, to November 5, 2019, with the last patient followed up on December 27, 2019. Data analysis was performed from February 2021 to February 2022. Exposure: Edoxaban (15 mg) once daily or placebo. Main Outcomes and Measures: The primary efficacy end point was the composite of stroke or systemic embolism, and the primary safety end point was major bleeding. Results: A total of 984 patients were randomly assigned to treatment (492 each to the edoxaban and placebo groups); 944 patients (402 frail patients [42.6%]; 542 nonfrail patients [57.4%]; mean [SD] age, 86.6 [4.3] years; 541 women [57.3%]) were included in this analysis. In the placebo group, the estimated event rates (SE) for stroke or systemic embolism were 7.1% (1.6%) per patient-year in the frail group and 6.1% (1.3%) per patient-year in the nonfrail group. Edoxaban was associated with lower event rates for stroke or systemic embolism with no interaction with frailty status or frailty assessment parameters. Major bleeding and major or clinically relevant nonmajor bleeding events were both numerically higher in the edoxaban group than in the placebo group, and no heterogeneity was observed with frailty status. Although both all-cause death and net clinical composite outcome occurred more frequently in the frail group than in the nonfrail group, there was no association with frailty status between the edoxaban and placebo groups. Conclusions and Relevance: Regardless of frailty status, among Japanese patients with AF aged 80 years or older who were ineligible for standard OACs, once-daily 15-mg edoxaban was associated with reduced incidence of stroke or systemic embolism and may be a suitable treatment option for these patients.

Laboratory Test Predictors for Major Bleeding in Elderly (≥80 Years) Patients With Nonvalvular Atrial Fibrillation Treated With Edoxaban 15 mg: Sub-Analysis of the ELDERCARE-AF Trial.

Background We investigated the predictors related to major bleeding events during treatment with edoxaban 15 mg in patients aged ≥80 years with nonvalvular atrial fibrillation and high bleeding risk, for whom standard oral anticoagulants are inappropriate, focusing on standard laboratory tests related to bleeding. Methods and Results This was a prespecified subanalysis of the on-treatment analysis set of the ELDERCARE-AF (Edoxaban Low-Dose for Elder Care Atrial Fibrillation Patients) trial. Major bleeding was the primary safety end point. The event rates were calculated according to prespecified characteristics at baseline. A total of 984 Japanese patients were randomly assigned to edoxaban 15 mg or placebo (n=492, each). During the study period, 20 and 11 major bleeding events occurred in the edoxaban and placebo groups, respectively. The adjusted analysis revealed that hemoglobin <12.3 g/dL (adjusted hazard ratio [aHR], 3.57 [95% CI, 1.10-11.55]) and prothrombin time ≥12.7 seconds; (aHR, 2.89 [95% CI, 1.05-8.02]) independently predicted major bleeding, while creatinine clearance <30 mL/min showed a tendency towards an increase in major bleeding (aHR, 2.68; 95% CI, 0.96-7.46). In patients treated with edoxaban lacking these 3 risk factors, no major bleeding occurred; major bleeding event rates increased with each risk factor. Patients with 3 risk factors were significantly more likely to have a major bleeding event at 11.05%/year (HR, 7.15 [95% CI, 1.92-26.71]). Conclusions In elderly patients with nonvalvular atrial fibrillation with high bleeding risk, baseline hemoglobin <12.3 g/dL, prothrombin time ≥12.7 seconds, and creatinine clearance <30 mL/min may predict major bleeding during treatment with edoxaban 15 mg. Registration URL: ELDERCARE-AF https://www.clinicaltrials.gov; Unique number: NCT02801669.

Impacts of Interaction of Mental Condition and Quality of Life between Donors and Recipients at Decision-Making of Preemptive and Post-Dialysis Living-Donor Kidney Transplantation.

Pre-emptive kidney transplantation (PEKT) is considered one of the most effective types of kidney replacement therapies to improve the quality of life (QOL) and physical prognosis of patients with end-stage renal disease (ESRD). In Japan, living-donor kidney transplantation is a common therapeutic option for patients undergoing dialyses (PDKT). Moreover, during shared decision-making in kidney replacement therapy, the medical staff of the multidisciplinary kidney team often provide educational consultation programmes according to the QOL and sociopsychological status of the ESRD patient. In Japan, the majority of kidney donations are provided by living family members. However, neither the psychosocial status of donors associated with the decision-making of kidney donations nor the interactions of the psychosocial status between donors and recipients have been clarified in the literature. In response to this gap, the present study determined the QOL, mood and anxiety status of donors and recipients at kidney transplantation decision-making between PEKT and PDKT. Deterioration of the recipient's QOL associated with "role physical" shifted the decision-making to PEKT, whereas deterioration of QOL associated with "role emotional" and "social functioning" of the recipients shifted the decision-making to PDKT. Furthermore, increased tension/anxiety and depressive mood contributed to choosing PDKT, but increased confusion was dominantly observed in PEKT recipients. These direct impact factors for decision-making were secondarily regulated by the trait anxiety of the recipients. Unlike the recipients, the donors' QOL associated with vitality contributed to choosing PDKT, whereas the physical and mental health of the donors shifted the decision-making to PEKT. Interestingly, we also detected the typical features of PEKT donors, who showed higher tolerability against the trait anxiety of reactive tension/anxiety than PDKT donors. These results suggest that choosing between either PEKT or PDKT is likely achieved through the proactive support of family members as candidate donors, rather than the recipients. Furthermore, PDKT is possibly facilitated by an enrichment of the life-work-family balance of the donors. Therefore, multidisciplinary kidney teams should be aware of the familial psychodynamics between patients with ESRD and their family members during the shared decision-making process by continuing the educational consultation programmes for the kidney-replacement-therapy decision-making process.

Structural basis for inhibition of the replication licensing factor Cdt1 by geminin.

To maintain chromosome stability in eukaryotic cells, replication origins must be licensed by loading mini-chromosome maintenance (MCM2-7) complexes once and only once per cell cycle. This licensing control is achieved through the activities of geminin and cyclin-dependent kinases. Geminin binds tightly to Cdt1, an essential component of the replication licensing system, and prevents the inappropriate reinitiation of replication on an already fired origin. The inhibitory effect of geminin is thought to prevent the interaction between Cdt1 and the MCM helicase. Here we describe the crystal structure of the mouse geminin-Cdt1 complex using tGeminin (residues 79-157, truncated geminin) and tCdt1 (residues 172-368, truncated Cdt1). The amino-terminal region of a coiled-coil dimer of tGeminin interacts with both N-terminal and carboxy-terminal parts of tCdt1. The primary interface relies on the steric complementarity between the tGeminin dimer and the hydrophobic face of the two short N-terminal helices of tCdt1 and, in particular, Pro 181, Ala 182, Tyr 183, Phe 186 and Leu 189. The crystal structure, in conjunction with our biochemical data, indicates that the N-terminal region of tGeminin might be required to anchor tCdt1, and the C-terminal region of tGeminin prevents access of the MCM complex to tCdt1 through steric hindrance.

Effects of aphid parasitism on host plant fitness in an aphid-host relationship.

Aphids are serious agricultural insect pests which exploit the phloem sap of host plants and thus transmit pathogens to their hosts. However, the degree to which aphid parsitism affects the fitness of the host plants is not well understood. The aphid, Macrosiphoniella yomogicola, parasitizes the mugwort Artemisia montana in Japan. During summer most mugworts carry aphids, but most aphid colonies die out after the budding of A. montana inflorescences in late summer. A few aphid colonies survive to late autumn, at which point sexuparae appear to later lay overwintering eggs after copulation. The death of the aphid colonies seems to be caused by biochemical changes in the phloem sap in the host plant coincident with the budding of inflorescences. The surviving aphid colonies may suppress the budding of inflorescences to allow persistence of their genetic line into the following year. Our investigations demonstrate that aphid parasitism did not affect host plant growth, but that it did significantly decrease the number of inflorescences and the average weight of floral buds. Our results indicate that aphid parasitism has a strong negative effect on the fitness of host plants. The manner in which the aphids suppress floral budding in their hosts is worth examining from the perspective of the evolution of aphid-plant interactions.

Ants improve the reproduction of inferior morphs to maintain a polymorphism in symbiont aphids.

Identifying stable polymorphisms is essential for understanding biodiversity. Distinctive polymorphisms are rare in nature because a superior morph should dominate a population. In addition to the three known mechanisms for polymorphism persistence, we recently reported a fourth mechanism: protection of the polymorphism by symbionts. Attending ants preferentially protect polymorphic aphid colonies consisting of green and red morphs. Here, we show that attending ants manipulate the reproductive rate of their preferred green morphs to equal that of the red morphs, leading to the persistence of the polymorphism within the colonies. We could not, however, explain how the ants maintained the polymorphism in aphid colonies regardless of inter-morph competition. Manipulation by symbionts may be important for the maintenance of polymorphisms and the resulting biodiversity in certain symbiotic systems.

Adaptive phenotypic variation among clonal ant workers.

Phenotypic variations are observed in most organisms, but their significance is not always known. The phenotypic variations observed in social insects are exceptions. Genetically based response threshold variances have been identified among workers and are thought to play several important adaptive roles in social life, e.g. allocating tasks among workers according to demand, promoting the sustainability of the colony and forming the basis of rationality in collective decision-making. Several parthenogenetic ants produce clonal workers and new queens by asexual reproduction. It is not clearly known whether such genetically equivalent workers show phenotypic variations. Here, we demonstrate that clonal workers of the parthenogenetic ant Strumigenys membranifera show large threshold variances among clonal workers. A multi-locus genetic marker confirmed that colony members are genetic clones, but they showed variations in their sucrose response thresholds. We examined the changing pattern of the thresholds over time generating hypotheses regarding the mechanism underlying the observed phenotypic variations. The results support the hypothesis that epigenetic modifications that occur after eclosion into the adult form are the cause of the phenotypic variations in this asexual species.

The benefits of grouping as a main driver of social evolution in a halictine bee.

Over the past decade, the cause of sociality has been much debated. Inclusive fitness [br in Hamilton's rule (br - c > 0)] has been criticized but is still useful in the organization of a framework by elucidating mechanisms through which br (benefit × relatedness) becomes larger than c (cost). The bee Lasioglossum baleicum is suitable for investigation of this issue because of the sympatric occurrence of both social and solitary nesting in its populations. We show that a large part (approximately 92%) of the inclusive fitness of a eusocial worker can be attributed to the benefits of grouping. A 1.5-fold relatedness asymmetry benefit in singly mated haplo-diploids explains a small part (approximately 8.5%) of the observed inclusive fitness. Sociality enables this species to conduct foraging and nest defense simultaneously, which is not the case in solitary nests. Our results indicate that this benefit of grouping is the main source of the increased inclusive fitness of eusocial workers.

Licensing for DNA replication requires a strict sequential assembly of Cdc6 and Cdt1 onto chromatin in Xenopus egg extracts.

Replication origins are licensed for a single initiation event by the loading of Mcm2-7 proteins during late mitosis and G1. Sequential associations of origin recognition complex, Cdc6 and Mcm2-7 are essential for completion of the licensing. Although Cdt1 also binds to the chromatin when the licensing reaction takes place, whether the binding is a requirement for Cdt1 to function is unclear. To analyze the relevance of the chromatin association of Cdt1, we carried out chromatin transfer experiments using either immunodepleted Xenopus egg extracts or purified proteins. Licensing assay and immunoblotting analyses indicated that Cdt1 could only license DNA replication and load Mcm2-7 onto DNA when it binds to chromatin that has already associated with Cdc6. These results provide evidence supporting that Cdc6 and Cdt1 must bind to chromatin in a strict order for DNA licensing to occur.

Nature of collective decision-making by simple yes/no decision units.

The study of collective decision-making spans various fields such as brain and behavioural sciences, economics, management sciences, and artificial intelligence. Despite these interdisciplinary applications, little is known regarding how a group of simple 'yes/no' units, such as neurons in the brain, can select the best option among multiple options. One prerequisite for achieving such correct choices by the brain is correct evaluation of relative option quality, which enables a collective decision maker to efficiently choose the best option. Here, we applied a sensory discrimination mechanism using yes/no units with differential thresholds to a model for making a collective choice among multiple options. The performance corresponding to the correct choice was shown to be affected by various parameters. High performance can be achieved by tuning the threshold distribution with the options' quality distribution. The number of yes/no units allocated to each option and its variability profoundly affects performance. When this variability is large, a quorum decision becomes superior to a majority decision under some conditions. The general features of this collective decision-making by a group of simple yes/no units revealed in this study suggest that this mechanism may be useful in applications across various fields.