Cell death induction and protection by activation of ubiquitously expressed anion/cation channels. Part 3: the roles and properties of TRPM2 and TRPM7

Cell volume regulation (CVR) is a prerequisite for animal cells to survive and fulfill their functions. CVR dysfunction is essentially involved in the induction of cell death. In fact, sustained normotonic cell swelling and shrinkage are associated with necrosis and apoptosis, and thus called the necrotic volume increase (NVI) and the apoptotic volume decrease (AVD), respectively. Since a number of ubiquitously expressed ion channels are involved in the CVR processes, these volume-regulatory ion channels are also implicated in the NVI and AVD events. In Part 1 and Part 2 of this series of review articles, we described the roles of swelling-activated anion channels called VSOR or VRAC and acid-activated anion channels called ASOR or PAC in CVR and cell death processes. Here, Part 3 focuses on therein roles of Ca2+-permeable non-selective TRPM2 and TRPM7 cation channels activated by stress. First, we summarize their phenotypic properties and molecular structure. Second, we describe their roles in CVR. Since cell death induction is tightly coupled to dysfunction of CVR, third, we focus on their participation in the induction of or protection against cell death under oxidative, acidotoxic, excitotoxic, and ischemic conditions. In this regard, we pay attention to the sensitivity of TRPM2 and TRPM7 to a variety of stress as well as to their capability to physicall and functionally interact with other volume-related channels and membrane enzymes. Also, we summarize a large number of reports hitherto published in which TRPM2 and TRPM7 channels are shown to be involved in cell death associated with a variety of diseases or disorders, in some cases as double-edged swords. Lastly, we attempt to describe how TRPM2 and TRPM7 are organized in the ionic mechanisms leading to cell death induction and protection

Quality of life and physical/psychosocial factors in children and adolescents with orthostatic intolerance

Background　Orthostatic intolerance (OI), which is common in children and adolescents, negatively impacts their quality of life (QOL) due to physical symptoms that limit work, school, and daily activities. The purpose of this study is to explore the association of physical and psychosocial factors with QOL scores in children and adolescents with OI. Methods　A cross sectional observational study was conducted. The study participants included 95 Japanese pediatric patients of age 9-15 years who were diagnosed with OI from April 2010 to March 2020. The QOL scores and the QOL T-scores of children with OI assessed using the KINDL-R questionnaire at the initial visit were compared with conventional normative data. The associations of physical and psychosocial factors with the QOL T-scores were examined using multiple linear regression. Results　Pediatric patients with OI had significantly lower QOL scores than healthy children in both elementary (50.7 +/- 13.5 vs. 67.9 +/- 13.4, p Conclusions　These results suggest that the assessment of QOL, including both physical and psychosocial aspects, especially school factors, needs to be implemented earlier in children and adolescents with OI

Srv2/CAP is required for polarized actin cable assembly and patch internalization during clathrin-mediated endocytosis

The dynamic assembly and disassembly of actin filaments is essential for the formation and transport of vesicles during endocytosis. In yeast, two types of actin structures, namely cortical patches and cytoplasmic cables, play a direct role in endocytosis, but how their interaction is regulated remains unclear. Here, we show that Srv2/CAP, an evolutionarily conserved actin regulator, is required for efficient endocytosis owing to its role in the formation of the actin patches that aid initial vesicle invagination and of the actin cables that these move along. Deletion of the SRV2 gene resulted in the appearance of aberrant fragmented actin cables that frequently moved past actin patches, the sites of endocytosis. We find that the C-terminal CARP domain of Srv2p is vitally important for the proper assembly of actin patches and cables; we also demonstrate that the N-terminal helical folded domain of Srv2 is required for its localization to actin patches, specifically to the ADP-actin rich region through an interaction with cofilin. These results demonstrate the in vivo roles of Srv2p in the regulation of the actin cytoskeleton during clathrin-mediated endocytosi

Protein-protein interactions of the hyperthermophilic archaeon Pyrococcus horikoshii OT3

BACKGROUND: Although 2,061 proteins of Pyrococcus horikoshii OT3, a hyperthermophilic archaeon, have been predicted from the recently completed genome sequence, the majority of proteins show no similarity to those from other organisms and are thus hypothetical proteins of unknown function. Because most proteins operate as parts of complexes to regulate biological processes, we systematically analyzed protein-protein interactions in Pyrococcus using the mammalian two-hybrid system to determine the function of the hypothetical proteins. RESULTS: We examined 960 soluble proteins from Pyrococcus and selected 107 interactions based on luciferase reporter activity, which was then evaluated using a computational approach to assess the reliability of the interactions. We also analyzed the expression of the assay samples by western blot, and a few interactions by in vitro pull-down assays. We identified 11 hetero-interactions that we considered to be located at the same operon, as observed in Helicobacter pylori. We annotated and classified proteins in the selected interactions according to their orthologous proteins. Many enzyme proteins showed self-interactions, similar to those seen in other organisms. CONCLUSION: We found 13 unannotated proteins that interacted with annotated proteins; this information is useful for predicting the functions of the hypothetical Pyrococcus proteins from the annotations of their interacting partners. Among the heterogeneous interactions, proteins were more likely to interact with proteins within the same ortholog class than with proteins of different classes. The analysis described here can provide global insights into the biological features of the protein-protein interactions in P. horikoshii

Antibiotic-dependent instability of homeostatic plasticity for growth and environmental load

Reducing antibiotic usage in livestock animals has become an urgent issue worldwide to prevent antimicrobial resistance. Here, abuse of chlortetracycline (CTC), a versatile antibacterial agent, on the performance, blood components, fecal microbiota, and organic acid concentration in calves was investigated. Japanese Black calves were fed milk replacer containing CTC at 10 g/kg (CON) or 0 g/kg (EXP). Growth performance was not affected by CTC administration. However, CTC administration altered the correlation between fecal organic acids and bacterial genera. Machine learning methods such as association analysis, linear discriminant analysis, and energy landscape analysis revealed that CTC administration affected according to certain rules the population of various types of fecal bacteria. It is particularly interesting that the population of several methane-producing bacteria was high in the CON, and that of Lachnospiraceae, a butyrate-producing bacteria, was high in the EXP at 60 d of age. Furthermore, statistical causal inference based on machine learning data estimated that CTC treatment affects the entire intestinal environment, inhibiting butyrate production for growth and biological defense, which may be attributed to methanogens in feces. Thus, these observations highlight the multiple harmful impacts of antibiotics on intestinal health and the potential production of greenhouse gas in the calves

Inhibition of bone erosion, determined by high-resolution peripheral quantitative computed tomography (HR-pQCT), in rheumatoid arthritis patients receiving a conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) plus denosumab vs csDMARD therapy alone: an open-label, randomized, parallel-group study

Background: This exploratory study compared the inhibition of bone erosion progression in rheumatoid arthritis (RA) patients treated with a conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) plus denosumab versus csDMARD therapy alone and investigated the effects of denosumab on bone micro-architecture and other bone-related parameters using high-resolution peripheral quantitative computed tomography (HR-pQCT).Methods: In this open-label, randomized, parallel-group study, patients with RA undergoing treatment with a csDMARD were randomly assigned (1:1) to continue csDMARD therapy alone or to continue csDMARDs with denosumab (60-mg subcutaneous injection once every 6 months) for 12 months. The primary endpoint was the change from baseline in the depth of bone erosion, measured by HR-pQCT, in the second and third metacarpal heads at 6 months after starting treatment. Exploratory endpoints were also evaluated, and adverse events (AEs) were monitored for safety.Results: In total, 46 patients were enrolled, and 43 were included in the full analysis set (csDMARDs plus denosumab, N = 21; csDMARD therapy alone, N = 22). Most patients were female (88.4%), and the mean age was 65.3 years. The adjusted mean (95% confidence interval) change from baseline in the depth of bone erosion, measured by HR-pQCT, in the 2–3 metacarpal heads at 6 months was − 0.57 mm (− 1.52, 0.39 mm) in the csDMARDs plus denosumab group vs − 0.22 mm (− 0.97, 0.53 mm) in the csDMARD therapy alone group (between-group difference: − 0.35 mm [− 1.00, 0.31]; P = 0.2716). Similar results were shown for the adjusted mean between-group difference in the width and volume of bone erosion of the 2–3 metacarpal heads. Significant improvements in bone micro-architecture parameters were shown. The incidence of AEs and serious AEs was similar between the csDMARDs plus denosumab and the csDMARD therapy alone groups (AEs: 52.2% vs 56.5%; serious AEs: 4.3% vs 8.7%).Conclusions: Although the addition of denosumab to csDMARDs did not find statistically significant improvements in bone erosion after 6 months of treatment, numerical improvements in these parameters suggest that the addition of denosumab to csDMARDs may be effective in inhibiting the progression of bone erosion and improving bone micro-architecture