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Neuroethics is the study of how neuroscience impacts humans and society. About 15 years have passed since neuroethics was introduced to Japan, yet the field of neuroethics still seeks developed methodologies and an established academic identity. In light of progress in neuroscience and neurotechnology, the challenges for Japanese neuroethics in the 2020 s can be categorized into five topics. (1) The need for further research into the importance of informed consent in psychiatric research and the promotion of public-patient engagement. (2) The need for a framework that constructs a global environment for neuroscience research that utilizes reliable samples and data. (3) The need for ethical support within a Japanese context regarding the construction of brain banks and the research surrounding their use. It is also important to reconsider the moral value of the human neural system and make comparisons with non-human primates. (4) An urgent need to study neuromodulation technologies that intervene in emotions. (5) The need to reconsider neuroscience and neurotechnology from social points of view. Rules for neuroenhancements and do-it-yourself neurotechnologies are urgently needed, while from a broader perspective, it is essential to study the points of contact between neuroscience and public health.

Cancer cells secrete large amounts of extracellular vesicles (EVs) originating from multivesicular bodies (MVBs). Mature MVBs fuse either with the plasma membrane for release as EVs, often referred as to exosomes or with lysosomes for degradation. However, the mechanisms regulating MVB fate remain unknown. Here, we investigated the regulators of MVB fate by analyzing the effects of signaling inhibitors on EV secretion from cancer cells engineered to secrete luciferase-labeled EVs. Inhibition of the oncogenic MEK/ERK pathway suppressed EV release and activated lysosome formation. MEK/ERK-mediated lysosomal inactivation impaired MVB degradation, resulting in increased EV secretion from cancer cells. Moreover, MEK/ERK inhibition prevented c-MYC expression and induced the nuclear translocation of MiT/TFE transcription factors, thereby promoting the activation of lysosome-related genes, including the gene encoding a subunit of vacuolar-type H

The serine protease Tk-subtilisin from the hyperthermophilic archaeon Thermococcus kodakarensis possesses three insertion loops (IS1-IS3) on its surface, as compared to its mesophilic counterparts. Although IS1 and IS2 are required for maturation of Tk-subtilisin at high temperatures, the role of IS3 remains unknown. Here, CD spectroscopy revealed that IS3 deletion arrested Tk-subtilisin folding at an intermediate state, in which the central nucleus was formed, but the subsequent folding propagation into terminal subdomains did not occur. Alanine substitution of the aspartate residue in IS3 disturbed the intraloop hydrogen-bonding network, as evidenced by crystallographic analysis, resulting in compromised folding at high temperatures. Taking into account the high conservation of IS3 across hyperthermophilic homologues, we propose that the presence of IS3 is important for folding of hyperthermophilic subtilisins in high-temperature environments.

FtsZ, a tubulin-like GTPase, is essential for bacterial cell division. In the presence of GTP, FtsZ polymerizes into filamentous structures, which are key to generating force in cell division. However, the structural basis for the molecular mechanism underlying FtsZ function remains to be elucidated. In this study, crystal structures of the enzymatic domains of FtsZ from Klebsiella pneumoniae (KpFtsZ) and Escherichia coli (EcFtsZ) were determined at 1.75 and 2.50 Å resolution, respectively. Both FtsZs form straight protofilaments in the crystals, and the two structures adopted relaxed (R) conformations. The T3 loop, which is involved in GTP/GDP binding and FtsZ assembly/disassembly, adopted a unique open conformation in KpFtsZ, while the T3 loop of EcFtsZ was partially disordered. The crystal structure of EcFtsZ can explain the results from previous functional analyses using EcFtsZ mutants.

A GH1 β-glucosidase from the fungus Hamamotoa singularis (HsBglA) has high transgalactosylation activity and efficiently converts lactose to galactooligosaccharides. Consequently, HsBglA is among the most widely used enzymes for industrial galactooligosaccharide production. Here, we present the first crystal structures of HsBglA with and without 4'-galactosyllactose, a tri-galactooligosaccharide, at 3.0 and 2.1 A resolutions, respectively. These structures reveal details of the structural elements that define the catalytic activity and substrate binding of HsBglA, and provide a possible interpretation for its high catalytic potency for transgalactosylation reaction.

Ribonuclease H2 (RNase H2) exhibits both single ribonucleotide excision activity (activity A) and RNA strand degrading activity (activity B). Val143 of human RNase H2 is located at the active site and is conserved in eukaryotic RNase H2. In this study, we explored the role of Val143 in catalytic activity and substrate specificity. Nineteen single variants at amino acid position 143 were expressed in E. coli, and all variants except for V143C and V143M were purified from the cells. When the activity of the wild-type human RNase H2 (WT) was set as 100%, the relative activities A and B of the 17 variants were in the range of 0.05-130 and 0.02-42%, respectively. When the ratio of the relative activity A to the relative activity B of WT was set as 1, the ratios of the 17 variants were in the range of 0.2-5.7. This indicates that valine is optimal for balancing the two activities. The ratios for V143Y and V143W were relatively high (5.6 and 5.5, respectively), suggesting that the bulky residues like tyrosine and tryptophan at position 143 caused steric hindrance with the 2'-OH of the sugar moiety of the ribonucleotide at the 5' side of the scissile phosphodiester bond. The ratio for V143Q was relatively low (0.2). These results suggested that Val143 is not critical for, but plays a role in determining catalytic activity and substrate specificity.

Breast cancer is the second leading cause of cancer-related deaths in the United States, with the majority of these deaths due to metastatic lesions rather than the primary tumor. Thus, a better understanding of the etiology of metastatic disease is crucial for improving survival. Using a haplotype mapping strategy in mouse and shRNA-mediated gene knockdown, we identified Rnaseh2c, a scaffolding protein of the heterotrimeric RNase H2 endoribonuclease complex, as a novel metastasis susceptibility factor. We found that the role of Rnaseh2c in metastatic disease is independent of RNase H2 enzymatic activity, and immunophenotyping and RNA-sequencing analysis revealed engagement of the T cell-mediated adaptive immune response. Furthermore, the cGAS-Sting pathway was not activated in the metastatic cancer cells used in this study, suggesting that the mechanism of immune response in breast cancer is different from the mechanism proposed for Aicardi-Goutières Syndrome, a rare interferonopathy caused by RNase H2 mutation. These results suggest an important novel, non-enzymatic role for RNASEH2C during breast cancer progression and add Rnaseh2c to a panel of genes we have identified that together could determine patients with high risk for metastasis. These results also highlight a potential new target for combination with immunotherapies and may contribute to a better understanding of the etiology of Aicardi-Goutières Syndrome autoimmunity., Author summary The majority of breast cancer-associated deaths are due to metastatic disease, the process where cancerous cells leave the primary tumor in the breast and spread to a new location in the body. To better understand the etiology of this process, we investigate the effects of gene expression changes in the primary tumor. In this study, we found that changing the expression of the gene Rnaseh2c changed the number of metastases that developed in the lungs of tumor-bearing mice. By investigating the enzyme complex Rnaseh2c is part of, RNase H2, we determined that Rnaseh2c’s effects may be independent of RNase H2 enzyme activity. Because Rnaseh2c is known to cause the autoimmune disease Aicardi-Goutières Syndrome (AGS), we tested whether the immune system is involved in the metastatic effect. Indeed, we found that the cytotoxic T cell response helps mediate the effect that Rnaseh2c has on metastasis. Together these data indicate that Rnaseh2c expression contributes to a patient’s susceptibility to developing breast cancer metastasis and demonstrate that the immune system is involved in this outcome. The implications of this study suggest immunotherapy could be a viable treatment for breast cancer metastasis and may help inform the understanding of AGS and RNase H2 in cancer.

The presence of ribonucleoside monophosphates (rNMPs) in nuclear DNA decreases genome stability. To ensure survival despite rNMP insertions, cells have evolved a complex network of DNA repair mechanisms, in which the ribonucleotide excision repair pathway, initiated by type 2 RNase H (RNase HII/2), plays a major role. We recently demonstrated that eukaryotic RNase H2 cannot repair damage, that is, ribose monophosphate abasic (both apurinic or apyrimidinic) site (rAP) or oxidized rNMP embedded in DNA. Currently, it remains unclear why RNase H2 is unable to repair these modified nucleic acids having either only a sugar moiety or an oxidized base. Here, we compared the endoribonuclease specificity of the RNase HII enzymes from the archaeon Pyrococcus abyssi and the bacterium Escherichia coli, examining their ability to process damaged rNMPs embedded in DNA in vitro. We found that E. coli RNase HII cleaves both rAP and oxidized rNMP sites. In contrast, like the eukaryotic RNase H2, P. abyssi RNase HII did not display any rAP or oxidized rNMP incision activities, even though it recognized them. Notably, the archaeal enzyme was also inactive on a mismatched rNMP, whereas the E. coli enzyme displayed a strong preference for the mispaired rNMP over the paired rNMP in DNA. On the basis of our biochemical findings and also structural modeling analyses of RNase HII/2 proteins from organisms belonging to all three domains of life, we propose that RNases HII/2's dual roles in ribonucleotide excision repair and RNA/DNA hydrolysis result in limited acceptance of modified rNMPs embedded in DNA.

A sheet-type shear force sensor and a measurement system for the sensor were developed. The sensor has an original structure where a liquid electrolyte is filled in a space composed of two electrode-patterned polymer films and an elastic rubber ring. When a shear force is applied on the surface of the sensor, the two electrode-patterned films mutually move so that the distance between the internal electrodes of the sensor changes, resulting in current increase or decrease between the electrodes. Therefore, the shear force can be calculated by monitoring the current between the electrodes. Moreover, it is possible to measure two-dimensional shear force given that the sensor has multiple electrodes. The diameter and thickness of the sensor head were 10 mm and 0.7 mm, respectively. Additionally, we also developed a measurement system that drives the sensor, corrects the baseline of the raw sensor output, displays data, and stores data as a computer file. Though the raw sensor output was considerably affected by the surrounding temperature, the influence of temperature was drastically decreased by introducing a simple arithmetical calculation. Moreover, the influence of pressure simultaneously decreased after the same calculation process. A demonstrative measurement using the sensor revealed the practical usefulness for on-site monitoring.

Hyperthermophiles are attractive sources of enzymes owing to their exceptional tolerance to chemical and thermal denaturation. The genome of a hyperthermophilic archaeon, Thermococcus kodakarensis KOD1, which optimally grows at 85°C, contains three genes encoding subtilisin-like serine proteases. We analyzed two of these, Tk-subtilisin and Tk-SP. Subtilisins from mesophilic bacteria have been widely used in the detergent industry, because of broad substrate specificity and ease of large-scale preparation. Tk-subtilisin and Tk-SP are approximately 40% identical to these mesophilic bacterial subtilisins, and exhibit extraordinarily high stability compared with the mesophilic homologs. These two hyperthermophilic subtilisins are potential candidates for application in biotechnological fields, and will provide good models for the study of maturation and stabilization mechanisms in all subtilisin-like proteases. Tk-subtilisin and Tk-SP are synthesized as prepro-enzymes. That is, a signal peptide and a propeptide are attached to the N-terminus of the mature domain, which is then secreted into the external medium as a pro-enzyme, with the assistance of the signal peptide. Most pro-enzymes then mature, undergoing three sequential steps: (1) the folding of mature domain, (2) autoprocessing of propeptide, and (3) degradation of propeptide, as well as bacterial subtilisin. However, the Tk-subtilisin and Tk-SP maturation mechanisms are different from those of bacterial subtilisins with respect to the requirements of the propeptide and Ca2+ ions for folding. Bacterial subtilisins require a cognate propeptide for folding. In contrast, Tk-subtilisin requires Ca2+ ions for folding, instead of a propeptide; and Tk-SP requires neither a propeptide, nor Ca2+ ions. Tk-subtilisin and Tk-SP both require Ca2+ ions for stability, as do bacterial subtilisins. A crystallographic analysis of Tk-subtilisin reveals seven Ca2+ ions in its mature domain, while Tk-SP displays two Ca2+ ions in its β-jelly roll domain. Four Ca2+ ions on Tk-subtilisin’s unique Ca2+ binding loop are responsible for folding, and the other three contribute to stability. The two Ca2+ ions in Tk-SP’s β-jelly roll domain contribute to its hyperstability. Tk-subtilisin and Tk-SP can degrade persistent proteins, such as abnormal prion proteins (PrPSc), to a level undetectable by western blot analysis, because both are highly tolerant to a wide variety of chemical denaturants, even in the presence of surfactants. Our results suggest that these two hyperstable proteases might be more useful for the medical decontamination of PrPSc than commercially employed enzymes. In this chapter, we summarize the unique maturation and stabilization mechanisms of Tk-subtilisin and Tk-SP, and discuss their potential for industrial applications.

Tk-subtilisin, a subtilisin homologue (Gly70-Gly398) from Thermococcus kodakarensis, is matured from its precursor, Pro-Tk-subtilisin [Tk-subtilisin in a pro form (Gly1-Gly398)], by autoprocessing and degradation of propeptide [Tk-propeptide, a propeptide of Tk-subtilisin (Gly1-Leu69)]. The scissile peptide bond between Leu69 and Gly70 of Pro-Tk-subtilisin is first self-cleaved to produce an inactive Tk-propeptide:Tk-subtilisin complex, in which the C-terminal region of Tk-propeptide binds to the active-site cleft of Tk-subtilisin. Tk-propeptide is then dissociated from Tk-subtilisin and degraded by Tk-subtilisin to release active Tk-subtilisin. To examine whether the mutation of Leu69 to Pro, which is the most unfavourable residue in the P1 position for subtilisins, affects the maturation of Pro-Tk-subtilisin, the Pro-Tk-subtilisin and Tk-propeptide derivatives with this mutation (Pro-L69P and L69P-propeptide) were constructed and characterized. Pro-L69P was autoprocessed more slowly than Pro-Tk-subtilisin. Nevertheless, it matured to Tk-subtilisin more rapidly than Pro-Tk-subtilisin because L69P-propeptide was degraded by Tk-subtilisin more rapidly than Tk-propeptide. The chaperone function and stability of L69P-propeptide were comparable to those of Tk-propeptide, whereas the inhibitory potency and binding ability of L69P-propeptide were considerably reduced compared to those of Tk-propeptide. The crystal structure of the complex between L69P-propeptide and S324A-subtilisin (i.e. a protease activity-defective mutant) revealed that the C-terminal region of L69P-propeptide does not well fit into the substrate binding pockets of Tk-subtilisin (S1-S4 subsites) as a result of a conformational change caused by the mutation. These results suggest that the Leu→Pro mutation accelerates the maturation of Pro-Tk-subtilisin by reducing the binding ability of Tk-propeptide to Tk-subtilisin.

Tk-subtilisin from the hyperthermophilic archaeon Thermococcus kodakarensis matures from Pro-Tk-subtilisin (Pro-TKS) upon autoprocessing and degradation of propeptide. Pro-TKS contains the insertion sequence (IS1) at the N-terminus of the mature domain as compared to bacterial pro-subtilisins. To analyze the role of IS1, the Pro-TKS derivative without IS1 (∆IS1-Pro-TKS) and its active-site mutants (∆IS1-Pro-S324A and ∆IS1-Pro-S324C) were constructed and characterized. ∆IS1-Pro-S324A and ∆IS1-Pro-TKS represent an unautoprocessed and autoprocessed form of ∆IS1-Pro-TKS, respectively. The CD and ANS fluorescence spectra of these proteins indicate that folding of ∆IS1-Pro-TKS is not completed by binding of Ca2+ ions but is completed by the subsequent autoprocessing reaction. Thermal denaturation of these proteins analyzed by DSC and CD spectroscopy indicates that unautoprocessed ∆IS1-Pro-TKS is less stable than autoprocessed ∆IS1-Pro-TKS by 26.3 °C in T m. The stability of autoprocessed ∆IS1-Pro-TKS is comparable to that of Pro-TKS, which is slightly lower than that of unautoprocessed Pro-TKS. These results suggest that ∆IS1-Pro-TKS is fully folded and greatly stabilized by autoprocessing. ∆IS1-Pro-TKS more slowly matured to ∆IS1-Tk-subtilisin than Pro-TKS did, due to a decrease in the autoprocessing rate. We propose that IS1 is required not only for hyperstabilization of Pro-TKS but also for its rapid maturation.

SUMMARY RNase H2 has two distinct functions: initiation of the ribonucleotide excision repair (RER) pathway by cleaving ribonucleotides (rNMPs) incorporated during DNA replication and processing the RNA portion of an R-loop formed during transcription. An RNase H2 mutant lacking RER activity but supporting R-loop removal revealed that rNMPs in DNA initiate p53-dependent DNA damage response and early embryonic arrest in mouse. However, an RNase H2 AGS-related mutant with residual RER activity develops to birth. Estimations of the number of rNMPs in DNA in these two mutants define a ribonucleotide threshold above which p53 induces apoptosis. Below the threshold, rNMPs in DNA trigger an innate immune response. Compound heterozygous cells, containing both defective enzymes, retain rNMPs above the threshold, indicative of competition for RER substrates between active and inactive enzymes, suggesting that patients with compound heterozygous mutations in RNASEH2 genes may not reflect the properties of recombinantly expressed proteins., Graphical Abstract, In Brief Uehara et al. use RNase H2 mice with differing activity levels for removal of rNMPs embedded in DNA. Moderate levels of rNMPs lead to perinatal lethality activating the cGAS-Sting DNA sensing innate immune response. Exceeding a threshold, high abundance of rNMPs activates p53-dependent DNA damage, causing early embryonic lethality.

This research aims to develop a combined sense system that uses both the force feedback and visual feedback to establish the shape of microscopic features of a microsample. It is thought that the efficiency of minute procedures would be improved if the operator could obtain a sense of force while using a manipulator. We used a cantilever to touch a minute object and obtain a reaction force from the degree of bending. We made a haptic device which gives a sense of that force to the operator, who can feel the force when a user touches a sample with a cantilever. In addition, when the haptic device is used in simulations, the user can feel a force just as if the user had touched a sample.

This paper aims to examine ethical implications of the cognitive enhancement based on neuroscience and neuro-technology: more specifically, its influences on the “self”. In order to do this, I begin with presenting the relevant conception of the self, and then examine how the cognitive enhancement could influence on the self. The opponents of the cognitive enhancement hold that it is self-destructive to accept cognitive enhancement since it will destroy our ordinary practices based on “folk psychology”. The proponents, however, may prefer new, neuroscientific practices, which do not need the concept of the self. Yet, the opponents still have ways out, resorting to our system of values. I will end this paper by pointing out some tasks which we must solve.

The theory of knowledge as a natural kind holds that knowledge has a theoretical unity in the causal structure of the world. Since knowledge supports causal explanation and prediction, we can investigate knowledge empirically like other natural kinds such as water. But epistemological nihilism holds that knowledge does not have such a theoretical unity because we can always observe the diversity of knowledge. This paper aims to defend the theory of knowledge as a natural kind from epistemological nihilism. To do this, I will suggest that we can understand knowledge as a biological kind like species or organs, and then accommodate the diversity of knowledge to this viewpoint positively.

Tk-subtilisin, a subtilisin homologue (Gly70-Gly398) from Thermococcus kodakarensis, is matured from its precursor, Pro-Tk-subtilisin [Tk-subtilisin in a pro form (Gly1-Gly398)], by autoprocessing and degradation of propeptide [Tk-propeptide, a propeptide of Tk-subtilisin (Gly1-Leu69)]. The scissile peptide bond between Leu69 and Gly70 of Pro-Tk-subtilisin is first self-cleaved to produce an inactive Tk-propeptide:Tk-subtilisin complex, in which the C-terminal region of Tk-propeptide binds to the active-site cleft of Tk-subtilisin. Tk-propeptide is then dissociated from Tk-subtilisin and degraded by Tk-subtilisin to release active Tk-subtilisin. To examine whether the mutation of Leu69 to Pro, which is the most unfavourable residue in the P1 position for subtilisins, affects the maturation of Pro-Tk-subtilisin, the Pro-Tk-subtilisin and Tk-propeptide derivatives with this mutation (Pro-L69P and L69P-propeptide) were constructed and characterized. Pro-L69P was autoprocessed more slowly than Pro-Tk-subtilisin. Nevertheless, it matured to Tk-subtilisin more rapidly than Pro-Tk-subtilisin because L69P-propeptide was degraded by Tk-subtilisin more rapidly than Tk-propeptide. The chaperone function and stability of L69P-propeptide were comparable to those of Tk-propeptide, whereas the inhibitory potency and binding ability of L69P-propeptide were considerably reduced compared to those of Tk-propeptide. The crystal structure of the complex between L69P-propeptide and S324A-subtilisin (i.e. a protease activity-defective mutant) revealed that the C-terminal region of L69P-propeptide does not well fit into the substrate binding pockets of Tk-subtilisin (S1-S4 subsites) as a result of a conformational change caused by the mutation. These results suggest that the Leu→Pro mutation accelerates the maturation of Pro-Tk-subtilisin by reducing the binding ability of Tk-propeptide to Tk-subtilisin.

Tk-subtilisin, a hyperthermostable subtilisin-like serine protease from Thermococcus kodakarensis, matures from the inactive precursor, Pro-Tk-subtilisin (Pro-TKS), upon autoprocessing and degradation of the propeptide (Tkpro). It contains seven Ca(2+) ions. Four of them (Ca2-Ca5) are responsible for folding of Tk-subtilisin. In this study, to clarify the role of the other three Ca(2+) ions (Ca1, Ca6, and Ca7), we constructed Pro-TKS derivatives lacking the Ca1 ion (Pro-TKS/ΔCa1), Ca6 ion (Pro-TKS/ΔCa6), and Ca7 ion (Pro-TKS/ΔCa7), and their active site mutants (Pro-S324A/ΔCa1, Pro-S324A/ΔCa6, and Pro-S324A/ΔCa7, respectively). Pro-TKS/ΔCa6 and Pro-TKS/ΔCa7 fully matured into their active forms upon incubation at 80 °C for 30 min as did Pro-TKS. The mature enzymes were as active as Tk-subtilisin at 80 °C, indicating that the Ca6 and Ca7 ions are not important for activity. In contrast, Pro-TKS/ΔCa1 matured poorly at 80 °C because of the instability of its mature domain. The enzymatic activity of Tk-subtilisin/ΔCa1 was determined to be 50% of that of Tk-subtilisin using the refolded protein. This result suggests that the Ca1 ion is required for the maximal activity of Tk-subtilisin. The refolding rates of all Pro-S324A derivatives were comparable to that of Pro-S324A (active site mutant of Pro-TKS), indicating that these Ca(2+) ions are not needed for folding of Tk-subtilisin. The stabilities of Pro-S324A/ΔCa1 and Pro-S324A/ΔCa6 were decreased by 26.6 and 11.7 °C, respectively, in T(m) compared to that of Pro-S324A. The half-lives of Tk-subtilisin/ΔCa6 and Tk-subtilisin/ΔCa7 at 95 °C were 8- and 4-fold lower than that of Tk-subtilisin, respectively. These results suggest that the Ca1, Ca6, and Ca7 ions, especially the Ca1 ion, contribute to the hyperthermostabilization of Tk-subtilisin.