16th Grant

I participated in the Tetrahedron Symposium 2023 held in Gothenburg, Sweden, and gave a presentation titled "Oxygen-Embedded Quinoline Oligomers: A New Entry to Macrocycles."

Specifically, I presented on the design, synthesis, and physicochemical properties of the multidentate ligands oxa-TriQuinoline (o-TQ) and oxa-TEtraQuinoline (o-TEQ), which are bridged by oxygen atoms with three or four quinoline ring units. These novel C3/S4 symmetric cyclic molecules can be easily synthesized via an SNAr reaction using the multifunctional unit 2-fluoroquinolin-8-ol as a substrate. According to their X-ray crystal structure analysis, the most stable conformation was thought to be one in which the coordination direction of each nitrogen atom alternates. However, adding specific metal salts resulted in a significant conformational change, yielding symmetric metal complexes. In particular, the formation of a copper(I) complex with o-TQ favored a bowl-shaped conformation, and its cationic curved π-surface acquired the ability to form supramolecular complexes with fullerene (C60)-related molecular groups and the macrocyclic π-molecule cycloparaphenylene. Furthermore, due to the semi-rigid structural properties of o-TQ/Cu(I), it also exhibits typical aggregation-induced emission (AIE) characteristics. By varying the fourth ligand to copper(I), its emission wavelength could be modulated to green, yellow, orange, and red, showing room-temperature emission with a maximum quantum yield of 24%. Additionally, we found that o-TQ, as a rigid tridentate ligand, functions as a catalyst for various reactions via copper/carbene or copper/nitrene formation mechanisms.

I was able to have in-depth discussions with international researchers from diverse backgrounds about the template-like effect, chirality control, and emission properties of o-TQ. I was also greatly inspired by listening to lectures from many renowned international researchers. Finally, I would like to take this opportunity to express my sincere gratitude to Sato Pharmaceutical Co., Ltd. for their generous support, which made this valuable opportunity possible.

(Toui Kobayashi, 3rd Year, Doctoral Programs, Graduate School of Pharmaceutical Sciences)

I participated in The 96th Annual Meeting of the Japanese Biochemical Society, held from October 31 to November 2 at the Fukuoka International Congress Center and Marine Messe Fukuoka Hall B, where I gave a poster presentation on the theme "Analysis of the molecular mechanism of the antitumor activity of the camptothecin derivative FL118 against myeloproliferative neoplasm cells."

I found that, compared to camptothecin, FL118 induces apoptosis in chronic myeloproliferative neoplasm cells at low concentrations. Measuring topoisomerase I activity confirmed that FL118 exhibits topoisomerase I inhibitory activity comparable to that of camptothecin. Therefore, it was considered that in addition to its topoisomerase I inhibitory activity, FL118 possesses 'some activity that induces apoptosis in MPN cells' which camptothecin lacks. In this study, I investigated the effect of FL118 on the activation of various signaling molecules in MPN cells. As a result, I newly discovered that FL118 suppresses the activation of the tyrosine kinase JAK2V617F mutant, the product of the causative gene for chronic myeloproliferative neoplasms, and presented this finding at the conference.

Currently, how FL118 regulates the activity of the JAK2V617F mutant is still unknown, and elucidating this is a future task. During the poster presentation, I was able to discuss the mechanism of JAK2 activation inhibition by FL118 with researchers from various fields. I hope to apply what I learned to my future research. Additionally, by participating in the conference, listening to many lectures and presentations, and learning about cutting-edge biochemical research, I found it to be a very educational experience.

Finally, I would like to express my deepest gratitude to Sato Pharmaceutical Co., Ltd. for their generous support in attending this conference.

(Kengo Takeda, 2nd Year, Doctoral Programs, Graduate School of Pharmaceutical Sciences)

I participated in the International Conference on Nano Research and Development (ICNRD-2023) held in Singapore, where I gave a poster presentation titled "Nanosized biomimetic red blood cells as an antidote for hydrogen sulfide poisoning with long-term storage stability."

Hydrogen sulfide exhibits rapid and lethal toxicity, and prompt initiation of treatment is required when poisoning is suspected. I focused on methemoglobin, which has high binding properties with hydrogen sulfide, and created methemoglobin-encapsulated liposomes (metHb-V) as an antidote for hydrogen sulfide poisoning. In this study, we evaluated the long-term stability of metHb-V as an antidote for hydrogen sulfide poisoning, anticipating its smooth clinical use. After storing metHb-V for one year at 4°C, room temperature, and 37°C, no changes in physicochemical properties or aggregation or fragmentation of methemoglobin within the liposomes were observed, and they were equivalent to pre-storage metHb-V. Therefore, when we evaluated the detoxifying effect of the stored metHb-V in lethally poisoned mice, it maintained an excellent detoxification ability comparable to that of pre-storage metHb-V. From these results, I presented that metHb-V can be a highly practical antidote for hydrogen sulfide poisoning that can be stored for a long time and lead to prompt treatment initiation.

I believe these research findings provide important evidence for developing an antidote for hydrogen sulfide poisoning, for which there are no approved existing drugs and no promising treatments. Furthermore, listening to presentations by global researchers allowed me to learn about ideas and originality from multiple perspectives, which greatly broadened my horizons. I intend to implement these insights into my own research projects in the future.

Finally, my participation in this conference was made possible by a research grant from Sato Pharmaceutical Co., Ltd. I would like to take this opportunity to express my heartfelt gratitude.

(Yuto Suzuki, 3rd Year, Ph.D. program, Graduate School of Pharmaceutical Sciences)

I participated in The 46th Annual Meeting of the Japan Neuroscience Society held in Sendai City, Miyagi Prefecture, and gave an oral presentation titled "Expression analysis of immune checkpoint molecules in microglia."

Microglia are immune cells resident in the central nervous system. In many central nervous system diseases, excessive activation and neurotoxicity of microglia are observed, but the regulatory mechanism of their activation is still unknown. Therefore, in this study, we focused on immune checkpoint molecules that regulate activated immune cells and reported our analysis of the expression of these molecules in microglia.

Many professors specializing in the nervous system participated in this conference, and I was able to learn about cutting-edge neuroscience. Furthermore, I discussed my research and the professors' research, receiving objective opinions and advice on my work, which I hope to apply to my future research activities. In my own presentation, I was able to experience giving an oral presentation in English for the first time. However, my vocabulary was insufficient, and I was unable to conduct a smooth Q&A session. As a result, I missed the opportunity to have even more in-depth discussions with the professors. In the future, I aim to improve not only my research activities but also my English presentation skills so that I can engage in more thorough discussions at my next presentation.

Finally, I would like to express my sincere gratitude to Sato Pharmaceutical Co., Ltd. for their generous support in the form of a research grant.

(Motoki Oshima, 1st Year, Master's Program, Graduate School of Pharmaceutical Sciences)

I participated in the FASEB Science Research Conference held in Colorado, USA, and gave a poster presentation titled "Purified diet feeding affects the morphology and functions of intestinal epithelial cells through the gut microbiota." I have been researching the effects of purified diets, which are widely used in various animal experiments, on intestinal epithelial cell function. As a result, I found that compared to mice fed a standard diet, mice fed a purified diet showed suppressed expression of molecules important for maintaining the epithelial barrier, such as intestinal epithelial cell proliferation, antimicrobial peptide production, and glycosylation. Furthermore, I clarified that the suppression of intestinal epithelial barrier function by a purified diet is induced by changes in the gut microbiota. Therefore, I concluded that it is necessary to consider the effects on the intestinal epithelium and gut microbiota when using purified diets in experiments, and I presented a summary of this data at the conference.

This conference is aimed at bringing together numerous basic researchers, clinicians, and graduate students to present and discuss the latest experimental data in intestinal epithelial cell research. During the conference, time was set aside not only for presentations but also for active discussions about each other's research while dining with many researchers. There, I received many pointers and pieces of advice from new perspectives that I could not have obtained from discussions within my own laboratory. I plan to use the comments I received to prepare for future paper submissions and to further advance my research.

This conference presentation was made possible by a research grant from Sato Pharmaceutical Co., Ltd. I would like to take this opportunity to express my sincere gratitude.

(Hiroaki Shiratori, 4th Year, Doctoral Programs, Graduate School of Pharmaceutical Sciences)

I participated in an English oral session at The 82nd Annual Meeting of the Japanese Cancer Association with a presentation titled "Potential utility of MCL-1 inhibitors for human biliary tract cancer with IDH1 mutations: Analysis using patient-derived human biliary tract cancer organoids."

Biliary tract cancer is known to be highly malignant and has a poor prognosis, second only to pancreatic cancer. IDH1 mutations are found in 15% of intrahepatic cholangiocarcinomas and are a suitable therapeutic target for personalized medicine. Although IDH1 mutations are also frequently observed in gliomas and acute myeloid leukemia, the different mutant alleles necessitate the elucidation of the effects of IDH1 mutations in biliary tract cancer and the development of new therapeutic methods.

I performed a metabolome analysis of human biliary tract cancer organoids established from patient tissues and reported the confirmation of 2-HG accumulation and decreased ATP production in IDH1 mutant strains, as reported in previous studies. I then presented that MCL-1 inhibitors specifically suppress the cell proliferation of IDH1 mutant strains and that this effect is related to the expression levels of BCL-2 family proteins, particularly MCL-1 and BCL-XL.

The Annual Meeting of the Japanese Cancer Association is a conference where many professors involved in cancer research and treatment from all over Japan gather, and it was a valuable opportunity to receive opinions from the perspectives of other researchers and engage in discussion. Additionally, by listening to the presentations of other professors, I was able to further broaden my knowledge, especially regarding biliary tract and pancreatic cancers.

Finally, I would like to take this opportunity to express my sincere gratitude to Sato Pharmaceutical Co., Ltd. for their generous support, which enabled me to successfully present at the conference.

(Shiho Suzuki, 1st Year, Master's Program, Graduate School of Pharmaceutical Sciences)

I participated in The 35th Symposium on Biomedical-Analytical Chemistry held at Hokkaido University and gave an oral presentation (10 minutes) for the first time at a conference. Although I had experience with poster presentations, I wanted to give an oral presentation at a conference where there was a good understanding of fluorescent probes, so I chose to participate in this conference, which is also welcoming to student oral presentations.

At this conference, I presented the establishment of a new molecular design method for fluorescent probes that detect enzyme activity, using "twisted intramolecular charge transfer" as the fluorescence control principle. We succeeded in quenching fluorescence by introducing a sterically bulky enzyme substrate moiety at a specific site in the molecular structure of rhodamine derivatives. Furthermore, the reaction by the target enzyme, nitroreductase, removed the enzyme substrate moiety, which resolved the intramolecular steric repulsion and resulted in an increase in fluorescence.

Since many researchers in physical and analytical pharmaceutical sciences who develop visualization probes such as fluorescent probes participated in this conference, I was able to receive valuable opinions and questions about my research results from the professors. For example, it was a good opportunity to think about future research directions, such as the possibility of mitochondrial depolarization caused by the addition of inhibitors and the potential for fluorescent dyes to aggregate within cells. Thanks to the support of Sato Pharmaceutical Co., Ltd., I was able to participate in a conference of my choice at Hokkaido University and give an oral presentation. Thank you very much.

Once again, in closing, I would like to express my sincere gratitude to Sato Pharmaceutical Co., Ltd. for their generous support for my conference presentation.

(Mizuki Sugimoto, 1st Year, Master's Program, Graduate School of Pharmaceutical Sciences)

I gave a poster presentation titled "Inhibition Kinetics of Citrus Jabara Juice on CYP3A4 Activity and Identification of Its Inhibitory Components" at the International Session of The 33rd Annual Meeting of the Japanese Society of Pharmaceutical Health Care and Sciences, held in Sendai City, Miyagi Prefecture.

Grapefruit juice is known to cause drug interactions by inhibiting the drug-metabolizing enzyme Cytochrome P450 (CYP) in a time-dependent manner (mechanism-based inhibition; MBI). In this study, we found that the juice of Jabara, a citrus fruit native to Japan, inhibits CYP3A4 through MBI. Furthermore, we identified a novel, previously unknown CYP3A4 inhibitory component in Jabara juice.

During the presentation, I received questions not only from domestic pharmacists but also from international pharmacists, giving me a valuable opportunity to discuss my research in English. In addition to the research content, I was also able to hear about the roles and initiatives of pharmacists overseas, and I feel that this conference broadened my perspective as a pharmacist.

Finally, I would like to express my heartfelt gratitude to Sato Pharmaceutical Co., Ltd. for their generous support in attending this conference.

(Kana Koinuma, 3rd Year, Doctoral Programs, Graduate School of Pharmaceutical Sciences)

Citrus juices such as grapefruit juice (GFJ) are known to inhibit the gastrointestinal absorption of substrate drugs like the hay fever medication fexofenadine (FEX) by inhibiting small intestinal organic anion-transporting polypeptides (OATPs) expressed in the small intestine. On the other hand, while the Japanese native citrus fruit Jabara and its juice are touted as effective for hay fever symptoms, they contain a large amount of the OATP-inhibiting component narirutin, which could potentially cause interactions via OATP inhibition. In this study, to elucidate the effect of Jabara juice on the small intestinal absorption of FEX, we conducted in vivo interaction experiments using mice and in vitro monolayer permeation experiments using the human gastrointestinal epithelial cell line Caco-2 and the P-glycoprotein (P-gp) overexpressing cell line LLC-GA5-COL300, which is an efflux transporter expressed in the small intestine, to evaluate the effect of Jabara juice. The results showed that Jabara juice significantly increased both the area under the blood concentration-time curve and the maximum blood concentration of FEX in mice by approximately twofold, and also enhanced the permeability of FEX across Caco-2 cell monolayers in vitro. Furthermore, since the Jabara juice extract inhibited the efflux activity of P-gp in a concentration-dependent manner, it became clear that Jabara juice enhances FEX absorption primarily through P-gp inhibition rather than OATP inhibition. The results obtained in this study suggest that, unlike fruit juices such as GFJ, Jabara juice increases the small intestinal absorption of FEX mainly by inhibiting small intestinal efflux transporters like P-gp. Clinically, caution should be exercised when co-administering Jabara juice with oral drugs.

This research was presented orally at "The 6th Freshers' Conference" and is scheduled to be published in the English academic journal "Biological and Pharmaceutical Bulletin," Vol. 46, No. 12.

This research presentation was supported by Sato Pharmaceutical Co., Ltd. Thank you very much.

(Hongye Han, 3rd Year, Doctoral Programs, Graduate School of Pharmaceutical Sciences)