Discovery of natural products that possess novel chemical structures and pharmaceutical activities increases opportunities of drug development. Filamentous fungi have been recognized as an attractive source for pharmaceutically beneficial natural products. Genome sequencing innovation represented by Next-generation sequencer opened fungal genomes one after another, suggesting that one fungal strain has far more biosynthetic gene clusters than that are estimated from the number of previously isolated natural products. In addition, bioinformatics analyses have indicated that most biosynthetic gene clusters are silent under laboratory culture conditions and there are a huge number of natural products hidden in the fungal genome. Therefore, we focused on those silent biosynthetic gene clusters as a potential source for novel natural products and developed methods to activate silent biosynthetic gene clusters by using low molecular weight molecules. In this review, we describe on discovery of novel natural products through activating fungal silent biosynthesis by addition of epigenetic modifiers and plant hormones.

Prolyl isomerase Pin1 is associated with various substrates and controls their functions through the isomerization of proline. Interestingly, a high fat diet increases Pin1 levels in adipose tissues. Accordingly, we investigated how Pin1 regulates energy metabolism in adipose tissues. Currently, adipocytes are divided into three types with distinct features. White adipocytes (WATs) store energy as triglycerides under fed conditions and release non-esterified fatty acids and glycerol through lipolysis while fasting. Brown and beige adipocytes, which exist in subcutaneous fat (scWAT), promote energy consumption through thermogenesis. We found that Pin1 impacts both thermogenesis and lipolysis upon interaction with distinct substrates. When mice were exposed to cold stress, both brown adipose tissues (BAT) and scWAT from adipocyte-specific Pin1 knockout (KO) mice showed higher expression levels of thermogenic genes in comparison to those from wild-type mice. Furthermore, we observed that Pin1 binds to the PRDM16 transcriptional cofactor, a major contributor to thermogenic programs, and promotes its degradation. Therefore, Pin1 suppresses thermogenesis. Meanwhile, in white adipocytes, Pin1 is involved in lipolysis. Pin1 deficiency enhanced lipolysis activity in epididymal WAT (epiWAT), but not in scWAT and BAT. In epiWAT, Pin1 interacts with adipose triglyceride lipase (ATGL) which is a rate-limiting enzyme for lipolysis, and downregulates ATGL levels. Finally, adipocyte-specific Pin1 KO mice have less body weight and better glucose metabolism under high fat diet conditions. These observations indicate that Pin1 is involved in the function of adipocytes through its association with PRDM16 and ATGL. Pin1 inhibitors could have therapeutic applications in the treatment of obesity.

Depression of lipid metabolism in β-cells has been indicated to be one of the causes of impaired insulin secretion in type 2 diabetes. Diacylglycerol (DAG) is an important lipid mediator and is known to regulate insulin secretion in pancreatic β-cells. Intracellular DAG accumulation is involved in β-cell dysfunction in the pathogenesis of type 2 diabetes; thus, the regulation of intracellular DAG levels is likely important for maintaining the β-cell function. We focused on diacylglycerol kinases (DGKs), which strictly regulate intracellular DAG levels, and analyzed the function of type I DGKs (DGKα, γ), which are activated by intracellular Ca²⁺ and expressed in the cytoplasm, in β-cells. The suppression of the DGKα and γ expression decreased the insulin secretory response, and the decreased expression of DGKα and γ was observed in islets of diabetic model mice. In the pancreatic β-cell line MIN6, 1 μM R59949 (a type I DGK inhibitor) and 10 μM DiC₈ (a cell permeable DAG analog) enhanced glucose-induced [Ca²⁺]_i oscillation in a PKC-dependent manner, while 10 μM R59949 and 100 μM DiC₈ suppressed [Ca²⁺]_i oscillation and voltage-dependent Ca²⁺ channel activity in a PKC-independent manner. These results suggest that the intracellular accumulation of DAG by the loss of the DGKα and γ functions regulates insulin secretion in a dual manner depending on the degree of DAG accumulation. The regulation of the insulin secretory response through DAG metabolism by type I DGKs may change depending on the degree of progression of type 2 diabetes.

In adult diseases, chronic inflammation-related angiopathy is the main pathological condition of organ disorders such as arteriosclerosis, chronic kidney disease, and non-alcoholic steatohepatitis (NASH). Macrophages play an important role in chronic inflammation. For example, macrophage foaming is important for atherosclerosis development. In our study using Apolipoprotein E knockout mice, hyperglycemia caused by the administration of nicotinamide-streptozotocin, which is a non-obese type 2 diabetes model, promoted arteriosclerosis, while the administration of sodium glucose co-transporter 2 inhibitor markedly reduced lesions. In further studies, arteriosclerosis was ameliorated in resistin like molecule β knockout mice, or by xanthine inhibitors. Xanthine oxidase (XO) inhibitors also improved kidney damage in a diabetic renal disorder model using KK/Ay mice and liver damage in a NASH model using high-fat, high-sucrose trans fatty acid loading. These studies suggested that atherosclerosis can be ameliorated independently of glucose and/or lipid lowering therapy, by interventions targeting macrophages. In a study using J774.1 cells, acetylated low density lipoprotein (LDL), which is a typical denatured LDL, is taken up by macrophages regardless of glucose concentrations, but very low density lipoprotein (VLDL) is taken up into cells in a glucose-dependent manner. The glucose concentration-dependent uptake of VLDL was suppressed by XO inhibitors. In addition, the overexpression of XO increased the VLDL uptake and the VLDLR expression was also increased. The glucose and nucleic acid metabolism, which are associated with its metabolism, are involved in the uptake of VLDL. In conclusion, it was strongly suggested that macrophages regulate inflammation and intracellular lipids depending on metabolism and that they may be involved in angiopathy in adult diseases.

The increasing prevalence of obesity worldwide has become an alarming public health concern because of dramatic increases in the incidence of obesity-associated diseases, including type 2 diabetes mellitus (T2DM). Peripheral insulin resistance and impaired insulin secretion remain the core defects in T2DM. Despite significant advances in unraveling the mechanisms underlying these defects, many of the metabolic pathways and regulators involved in insulin resistance and β-cell dysfunction are not completely understood. This review proposes that manipulating the fatty acid (FA) composition by blocking ELOVL fatty acid elongase 6 (Elovl6) could protect against insulin resistance, impaired insulin secretion, and obesity-related disorders. Elovl6 is a microsomal enzyme involved in the elongation of C16 saturated and monounsaturated FAs to form C18 FAs. We have reported that mice with Elovl6 deletion are protected against obesity-induced insulin resistance or β-cell failure because the cellular FA composition is changed, even with concurrent obesity. Therefore, Elovl6 appears to be a crucial metabolic checkpoint, and limiting the expression or activity of Elovl6 could be a new therapeutic approach in the treatment of T2DM.

Three-dimensional structural information is indispensable to understand the function of proteins in living organisms and X-ray crystallography plays a major role in determining the three-dimensional structure. X-ray free-electron laser (XFEL), which is intense and femtosecond X-ray pulses, enables us to obtain X-ray diffraction intensity data before the destruction of protein molecules, and is expected to be a technology to obtain dynamic structural information. This year marks the 10th anniversary of SPring-8 Angstrom Compact Free Electron Laser (SACLA), Japan's X-ray free electron laser facility. In this review, I describe the damage-free crystal structure analysis, de novo crystal structure determination using single wavelength anomalous dispersion by serial femtosecond crystallography (SFX), and time-resolved X-ray crystallography that have been performed at SACLA.

Elucidation of molecular mechanism for metalloeznyme-catalyzed reactions is longstanding topics in the bio-inorganic chemistry field, since metalloeznymes play pivotal roles in various biological processes and catalyze reactions with high efficiency under mild conditions. Structural determination of reaction intermediates is key to visualizing the reactions catalyzed by metalloenzymes. Although it is not easy to determine the structure of the transient species by conventional crystallography, newly developed time-resolved X-ray crystallography using X-ray free electron laser (XFEL) has a great potential for the structural characterization of intermediates. However, XFEL-based time-resolved crystallography requires a photo-trigger, hampering its application to non-photosensitive proteins like metalloenzymes. Here, to overcome this issue, we focused on caged substrates, which produce the substrate upon photo-irradiation, to introduce the photo-trigger into the reaction catalyzed by the metalloenzyme. To demonstrate the usefulness of caged substrates for the trigger of XFEL-based time-resolved crystallography, soluble nitric oxide (NO) reductase, which catalyzes the reduction of NO to nitrous oxide (N₂O) at a heme active center, and caged NO were used as a model system. Time-resolved spectroscopic analysis showed that the photolysis of caged NO could initiate NO reduction by P450nor in the micro-crystals. Time-resolved crystallography using XFEL enabled us to determine the structures of two intermediates; NO-bound form and subsequent NO-activated form, which provided a unique opportunity to draw the complete picture of the reaction cycle of P450nor. Thus, the combination of caged substrate and XFEL-based time-resolved crystallography is an invaluable method for the visualization of the reactions catalyzed by metalloenzyems.

Photoresponsive molecules can be used to manipulate the physiological functions of cells with high spatiotemporal resolution. Caged compounds are photoresponsive molecules designed to temporarily mask their original biological activity through covalently bound photoremovable protecting groups. The introduction of additional properties into caged compounds without compromising photosensitivity would help expand the repertoire of caging groups. Therefore, we designed a modular caged compound consisting of three parts: a photoresponsive core, a chemical handle to introduce additional functionalities, and a molecule to be masked. We designed two modular precursors, NHS-Bhc-diazo, for caged phosphates and paBhcmoc-X, for caged alcohols and amines. NHS-Bhc-diazo was successfully applied to the synthesis of affinity-purifiable caged dsDNA with biotin tags. The modular precursor paBhcmoc-X was used to prepare a new water-soluble caged anticancer agent with improved photochemical properties. One of the barriers to the in vivo use of conventional caged compounds is that the caged compounds are not genetically encoded and cannot target the cells of interest. To overcome these limitations, we demonstrated the concept of gene-directed caged compounds that can be photoactivated with cell-type selectivity. We designed and synthesized new caged cyclic nucleotides as proof of concept. Photo-mediated release of the parent nucleotide was observed only in live mammalian cells expressing Escherichia coli β-galactosidase. As cells or tissues can be genetically tagged by an exogenously expressed enzyme, this new method can serve as a strategy for adding targeting abilities to photocaged compounds.

Technologies for the optical control of biomolecular functions have recently attracted considerable attention because they can be combined with advanced laser and microscopic techniques for diverse applications at the cellular and intravital levels. In this account, I review the summary of optical control technologies for biomolecular functions based on organic chemistry or protein science, and then introduce our recent studies on the development of small molecule-based photoregulation techniques. The first is the development of a photoactivatable protein labeling method based on a caged ligand. This method was applied to the photocontrol of intracellular protein dimerization and localization. The second is the development of a reversibly photoswitchable enzyme inhibitor, which was designed from the conformation of the inhibitor in the crystal structure of the enzyme-inhibitor complex. Based on our research strategies and results, I have also outlined the respective advantages and disadvantages of these two technologies: caged compounds and photoswitchable compounds.

Genetic information is replicated and transmitted from a parent cell to two identical daughter cells through mitotic cell division. To accomplish this dynamic process with high accuracy and precision, various motor proteins work in a concerted manner. Especially in the metaphase, mitotic chromosomes are delivered by the motor protein of centromere-associated protein E (CENP-E) to the cell equatorial plane (metaphase plate) along mitotic spindles. However, the critical functional failure of CENP-E can activate the spindle assembly checkpoint through the misalignment of chromosomes at the metaphase plate. In this symposium review, the reversibly photoswitchable CENP-E inhibitor PCEI-HU (5) is reported. Compound 5 exhibited almost quantitative trans-cis photoisomerization of the arylazopyrazole photoswitch by illuminating light at 365 nm and 510 nm. Depending on the photoisomerization, CENP-E activity was regulated not only in vitro but also in cells. We successfully established a novel technique using 5 to dynamically photocontrol the CENP-E-dependent chromosome movement and mitotic progression in a living cell.

Pharmacological cognitive enhancement (PCE) refers to the use of biochemical enhancers for achieving improved mental performance in healthy individuals. One particular use of PCE prevalence is the misuse of these enhancers among university students for academic performance enhancement. The prevalence rates demonstrate the use of a broad spectrum of substances for PCE that can be classified as OTC, prescription, and illegal drugs. Given that certain substances have been widely used for years, their long-term effectiveness and side effects in the healthy population are essential to know. The question of safety and efficacy or benefit versus risk is not only of individual and societal interest but also bears implications for regulatory and policy decision-making. As far as safety is concerned, there is a particular problem with healthy children, whose brains are still in development. Soft enhancers, such as energy drinks, might be commonly used worldwide. Performance pressure, stress, and psychiatric disorders may be associated with PCE use and need to be considered when planning anti-PCE-themed educational activities. In an increasingly complex information society, demands for cognitive functioning are growing; however, it is doubtful whether we should welcome the use of PCEs for the support of work productivity or the improvement of our life quality. Societal discussions on PCE might give an opportunity to consider a meaningful life in all aspects.

Antimicrobial stewardship (AS) intervention strategy is a critical process in promoting appropriate antibiotic use, thus preventing unnecessarily prolonged therapy and reducing antimicrobial resistance (AMR). Although limiting unnecessary carbapenem use by AS intervention is speculated to reduce AMR, there is a lack of specific data on the efficacy of AS team (AST) intervention regarding carbapenem-resistant Pseudomonas aeruginosa (CRPA). Consequently, this study aimed to evaluate the impact of our AS strategy on carbapenem use and CRPA. The AS intervention strategy was launched in July 2017 and consisted of daily audits and feedback on carbapenem use. We evaluated the 4-year prescription trend, including the rate of switching to other antimicrobials, and the rate of CRPA and the days of therapy required prior to and after the beginning of the AST intervention. The rate of switching to narrow-spectrum antibiotics and the discontinuation of carbapenem treatment were significantly higher in the pre-intervention period compared with the post-intervention period. (7.0% vs. 14.5%; p<0.001; 54.1% vs. 50.9%; p=0.027). However, there were no significant differences in the rate of CRPA prior to and after the beginning of the AST intervention. Furthermore, there was no correlation found between consumption and resistance rate (Pearson's r=0.123). Our results suggest that it is extremely important for AST to promote de-escalation and reduce unnecessary use, while the combination of process and outcome indicators other than antimicrobial consumption and resistance rate are required for the evaluation of the AS programs.

Transient receptor potential vanilloid 2 (TRPV2) channels are expressed and play functional roles in various immune cells. Physical stimuli leading to TRPV2 activation causes mast cell degranulation. Besides their roles in immune cells, it has been shown that TRPV2 channels are pathophysiologically relevant to degenerative muscular diseases such as dilated cardiomyopathy and muscular dystrophy. Hence, development of drug candidates that inhibit human TRPV2 activation is an urgent matter. NK-4, a cryptocyanine dye, inhibited agonist-induced TRPV2 activity in mouse TRPV2-transfected HEK293 cells. However, it remains unclear whether NK-4 exerts regulatory effects on the activation of human TRPV2 channels. In this study, we show that NK-4 inhibits intracellular Ca²⁺ increase in human TRPV2-transfected HEK293 cells preactivated with a TRPV2 agonist. The inhibitory effect of NK-4 (IC₅₀=0.27 μM) on human TRPV2 activation was 74-fold stronger than that on mouse TRPV2 activation (IC₅₀=20 μM). NK-4 also inhibited the agonist-induced TRPV2 expression at the plasma membrane, when the human TRPV2-expressing cells were stimulated with the agonist in the presence of NK-4. These results suggest that NK-4 abrogates the agonist-induced signaling events leading to human TRPV2 activation. Furthermore, TRPV2 agonist caused degranulation of RBL-2H3 cells, which represents a phenomenon related to physical urticarias. NK-4 suppressed the release of β-hexosaminidases upon degradation with IC₅₀ of 1.9 μM, 35-fold lower than that determined with an anti-allergic drug, Epinastine. Our results suggest that NK-4 would be a potential therapeutic strategy to resolve dilated cardiomyopathy and its associated heart failure as well as physical urticarias.

Biosimilars are less expensive than their originators, and Japanese government policies call for their development and promotion. However, the adoption and prescription of some biosimilars, especially antibody/its-related ones, have been delayed for use in Japan, possibly due to concerns on the differences in quality attributes such as glycan structures between the originators and their biosimilars, and that clinical efficacy/safety studies are conducted for usually one disease and its results extrapolated to other indications. We conducted a questionnaire survey among physicians in four disease areas (hematology, medical oncology, rheumatoid arthritis, and inflammatory bowel disease), where biosimilars of antibody/its-related drugs have been approved, regarding their thoughts on the adoption and prescription of biosimilars in Japan from January to April 2020. We received totally 1024 responses. When adopting biosimilars and explaining them to patients, physicians requested specific information including the comparative results of phase III clinical trials and quality characteristics between biosimilars and their originators; the results of clinical studies on switching from originators to their biosimilars; and a comparison of the estimated cost on patients in consideration of the high medical cost payment system. Priority differed depending on the studied disease areas. In terms of post-marketing information, physicians requested a variety of information. When explaining biosimilars to the patients, physicians would like to use general material from government describing the comparability between originators and their biosimilars. These results suggest that physicians sought more comparative information on the quality, efficacy, and patients' cost between originators and their biosimilars when adopting or prescribing biosimilars.