(a) Rendered image of the developed measurement system. (b) Enlarged view of the t-SPESI unit and the sample stage unit. (c) Photograph of the conventional ion transfer tube. (d) Photograph of the developed ion transfer tube. (ed) Comparison of the signal intensities of NaI cluster ions. In the legend, O and N indicate the results obtained using the ion transfer tubes shown in (c) and (d), respectively, and the numbers indicate the heater temperature.

The article, “Development of a Tapping-Mode Scanning Probe Electrospray Ionization Platform for High-Sensitivity and Long-Term Stability in Single-Cell Mass Spectrometry Imaging of Tissue,” was published in Analytical Chemistry at https://doi.org/10.1021/acs.analchem.6c02386.

Related links

• Associate Professor Otsuka Yoichi (Researcher Directory)

• Mass Spectrometry Group

• Eurkalert!
• AlphaGalileo
• Asia Research News
• ResOU（Research at Osaka University）website

Mitochondria are famously known as the powerhouse of the cell, but their functions go beyond energy generation: they also act as signaling centers, helping the cell to sense and respond to trouble. When mitochondria are ‘hyperfused’, i.e., the stressed, abnormally long state described above, they release their genetic material into the cytosol, where the cell treats it as a warning sign in the same way it would treat a virus.

Recent studies have highlighted that mitochondrial DNA and RNA released into the cytosol can activate innate immune signaling. However, how changes in mitochondrial morphology influence the release of mitochondrial RNA (mtRNA) and the resulting innate immune response has remained poorly understood. Researchers from the University of Osaka set out to clarify these mitochondrial mysteries, and their findings have now been published in Cell Reports.

By using cells engineered to lack DRP1 – preventing mitochondria from dividing – the team triggered hyperfusion and explored the subsequent gene activity. The RNA sequencing analysis demonstrated that genes activated during a typical immune response, interferon-stimulated genes, were upregulated. However, when the hyperfused mitochondria were restored to their normal morphology, the expression of these immune-related genes returned to baseline levels.

“We determined that the trigger was mtRNA leaking into the cytosol, activating RNA-sensing proteins, such as RIG-I and MDA5, which also activate when detecting RNA viruses,” explains lead author Tatsuki Yasuda. “Given the evolutionary origin of mitochondria as descendants of ancient bacteria, it is fascinating that mitochondrial RNA can activate the same surveillance pathways that normally detect invading pathogens.”

These results point to other settings where mitochondrial hyperfusion can arise, including some cancers. Exploring existing cancer datasets, the researchers found that tumors with low DRP1 levels showed higher activity of the same immune-activating genes. In the lab, cancer cells with hyperfused mitochondria were more readily destroyed by natural killer immune cells and failed to grow efficiently after implantation in mice, pointing to a mitochondrial route for stronger anti-tumor immunity.

“Our study identifies a previously unknown molecular mechanism linking mitochondrial morphology to innate immune activation,” says senior author Naotada Ishihara. “We hope these findings will stimulate further research into how mitochondrial dynamics regulate immune responses. Because mtRNA release may contribute to cancer as well as inflammatory and age-related diseases, this mechanism could have broad implications across a range of human disorders.”

The team hopes these findings open new avenues for research into mitochondrial biology and innate immunity. By revealing how mitochondrial shape influences immune signaling, the study provides a new framework for understanding not only cancer but also inflammatory and age-related diseases associated with mitochondrial dysfunction.

Mitochondrial hyperfusion triggers innate immune responses.

The article, “Disrupted mitochondrial dynamics activate RNA sensing innate immunity through mitochondrial RNA release”, was published in Cell Reports at DOI: https://doi.org/10.1016/j.celrep.2026.117607.

Related links

• Professor Ishihara Naotada (Researcher Directory)

• Ishihara Lab, Department of Biological Sciences

• Eurkalert!
• AlphaGalileo
• Asia Research News
• ResOU（Research at Osaka University）website

Now, researchers at the University of Osaka have overcome these limitations by developing a multipath synergistic strategy to toughen elastomers. This study has been published in Nature Communications.

Elastomers are polymers that are exceptionally elastic, i.e., they can deform strongly under external stress and revert to their original shape when the stress is removed. However, traditional elastomers are not very tough, as microscopic cracks can cause the material to tear.
Consequently, strategies are employed to enhance the toughness of elastomers by dissipating energy. That is, during deformation, the polymer absorbs mechanical energy and dissipates it by converting it into other forms of energy.

To reduce the likelihood of tears, three types of energy dissipation strategies can be employed.
i) Molecular sliding – Rotaxane molecules are incorporated into the elastomer, which slide and rotate under an external force, redistributing stress across the network and preventing breakage.
ii) Force-induced bond scission – Molecules are embedded in elastomers with “sacrificial” bonds that break under an applied stress, delaying damage to the elastomer.
iii) Chain entanglement – Molecular design is used to introduce structurally well-defined chain entanglements, which allow chains to slide and rearrange tension across the network when stress occurs.

Individual energy-dissipation strategies provide only a limited improvement in elastomer toughness. Although multiple mechanisms have been incorporated into a single material, achieving synergistic toughening by activating them sequentially as the applied stress increases remains challenging.

“We integrated three energy dissipation pathways that become activated in sequence under increasing stress to prevent failure of the elastomer,” explains lead author Xue Li. “Thus, we synergistically combined three toughening mechanisms.”

In this study, the authors introduced ring molecules with sacrificial bonds into an elastomer. Under applied stress, ring sliding occurs in the elastomer first to absorb force. As the stress increases, the rings cleave to form linear chains. Under even higher stress, the linear chains entangle with other chains, maintaining network connectivity and dissipating energy via chain slippage.

This novel strategy can be used to create materials that are both soft and durable, with uses such as tires, gloves, and adhesives. The superior toughness of these materials translates into improved service life and reliability.

Under an applied force, sequential molecular transformations suppress material failure

The article, “Toughening Elastomer via Sequentially Activated Multi-Pathway Energy Dissipation,” has been published in Nature Communications at DOI:
https://doi.org/10.1038/s41467-026-74148-z.

Related links

• Professor Yamaguchi Hiroyasu (Researcher Directory)

• Assistant Professor Kobayashi Yuichiro (Researcher Directory)

• Supramolecular Functional Chemistry Group

• Eurkalert!
• AlphaGalileo
• Asia Research News
• ResOU（Research at Osaka University）website

Now, researchers from The University of Osaka have reported a new way to bring ancient proteins back to life. The study, published in ACS Omega, has revealed that the developed methodology can help generate ancestral rhodopsins that can be tested experimentally in bacteria.

A wide range of microbes express proteins called microbial rhodopsins, which are embedded in the cell membrane and play a variety of roles, including pumping ions across the membrane or sensing light. Scientists have long wondered how members of this single family can possess such a wide array of functions, with investigations involving analyzing the protein sequences to determine their evolutionary history.

“Rhodopsins all have seven transmembrane domains that are very similar, but their extramembrane domains, which extend inside and outside of the cell, vary dramatically,” says lead author, Haruto Ishikawa. “This makes it very challenging to use standard sequence alignment techniques to trace the evolution of rhodopsin sequences from their shared ancestral proteins.”

To tackle this problem, the researchers analyzed the sequences of two different microbial rhodopsins, schizorhodopsins and heliorhodopsins, using an approach that specifically accounts for insertions and deletions in the extramembrane domains. Based on this technique, they reconstructed ancestral schizorhodopsin and heliorhodopsin sequences and expressed them in bacteria.

“The results were very exciting,” explains Yasuhisa Mizutani, senior author. “Both the ancestral schizorhodopsin sequence and the ancestral heliorhodopsin sequence produced stable, mature proteins in Escherichia coli that had a distinctive color and showed characteristic spectral properties, just like existing rhodopsins.”

Similar to contemporary schizorhodopsins, the ancestral schizorhodopsin showed light-driven proton-transport activity. In contrast, the ancestral heliorhodopsin did not pump ions, consistent with current heliorhodopsins.

“Our findings show that sequence reconstruction that takes insertions and deletions into account can successfully generate full-length ancestral rhodopsins that can be experimentally produced and tested,” explains Ishikawa.

The researchers have made their analytical pipeline, ConsistASR, available for other investigators to use. The ConsistASR workflow could help reconstruct and engineer other ancestral proteins, providing functional insight into protein evolution.

When E. coli cells producing ancestral rhodopsin (Anc-SzR) were illuminated, the pH of the surrounding solution increased. This result supports that the ancestral rhodopsin absorbs light and, like extant schizorhodopsins, transports hydrogen ions (H⁺) into the cells.

The article, “Resurrecting Full-length Ancestral Schizorhodopsins and Heliorhodopsins with Structure-guided, Indel-aware Sequence Reconstruction,” has been published in ACS Omega at https://doi.org/10.1021/acsomega.6c03010.

Related links

• Associate Professor (Lecturer) ISHIKAWA Haruto (Researcher Directory)

• Mizutzni Laboratory, Laboratory for Biophysical Chemistry

• Eurkalert!
• AlphaGalileo
• Asia Research News
• ResOU（Research at Osaka University）website

They were welcomed by Prof. Tadashi Kondo, Dean of the Graduate School of Science and Atsushi Takahashi, Vice Dean and Chair of the International Exchange Committee, along with members of the International Affairs Committee and related staff. The two sides held discussions aimed at moving toward full-scale implementation of the Double Degree Program (DDP) agreement concluded in June 2024. During the meeting, they shared information on laboratories that already have ongoing exchanges, as well as laboratories in overlapping research fields and areas in which they hope to further expand collaboration.
Taking this visit as an opportunity, both universities confirmed that they will make use of the DDP agreement to proceed with concrete arrangements for student acceptance and dispatch. They also shared various operational issues that need to be addressed in order to implement these exchanges.

Based on these discussions, we will continue to strengthen the cooperative relationship between the two universities and further examine concrete steps toward student and research exchanges, including the DDP.

(Scenes from the DDP signing ceremony:https://www.sci.osaka-u.ac.jp/en/news/9991_1/ )

[Visitors]
Prof. Luisella Celi, Vice Rector for Research
(Department of Agricultural, Forest and Food Sciences）
Prof. David Lembo, Vice Rector for International Relations
(Department of Clinical and Biological Sciences）
Prof. Federico Maria Petrucci, Rector’s Delegate for Humanities and Social Sciences Strategic Research
(Department of Philosophy and Education Sciences）
Prof. Stefania Maria Beolé, Rector’s Delegate for Natural and Life Sciences Strategic Research
(Department of Physics）
Mr. Stefano Palmieri, Press Office
Ms. Mariasilvia Ciola, Rector’s Advisor for International Projects
Dr. Ugo Falciola, Head of Commercial Office, the Consulate General of Italy in Osaka

[The University of Osaka]
Prof. Tadashi Kondo, Dean, the Graduate School of Science
(Department of Earth and Space Science)
Prof. Atsushi Takahashi , Vice Dean and Chair of the International Exchange Committee
(Department of Mathematics)
Prof. Hajime Nanjo, Member of the International Exchange Committee
(Department of Physics)
Prof. Nobuto Yoshinari , Member of the International Exchange Committee
(Department of Chemistry)
Prof. Yasuhiro Funahashi, Member of the International Exchange Committee
(Department of Chemistry)
Assoc. Prof. Osamu Urakawa , Member of the International Exchange Committee
(Department of Macromolecular Science)
Assoc. Prof. Tomoyuki Furuya, Member of the International Exchange Committee
(Department of Biological Sciences)
Assoc. Prof. Hirokazu Odaka, Member of the International Exchange Committee
(Department of Earth and Space Science)
Dr. Yuri Kamon(Lecturer), Member of the International Exchange Committee
(Center for International Affairs, Office of Research Administration)
Assoc. Prof. Luca Baiotti , International College

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Registration >> https://forms.cloud.microsoft/r/MZJafQufit
Please register in advance so we can prepare! However, walk-ins are also very welcome.

<Contents>
This event is for all you who want to overcome your weaknesses in English while having fun, who are interested in English, and who want to practice communicating in the English you learn, this is a great opportunity for you! You can get together to play games in English with international students and Japanese students and improve your English skills by receiving appropriate feedback from a native English-speaking instructor.
We are looking forward to your participation.

<Date>
Thursdays, June 18, 25, July 2, 9, and 23

<Time>
12:20〜13:05 Lesson offered by English instructor
13:05〜13:20 Free chat (you can leave any time if you take 3rd period class)

<Location>
Science Bldg. B208

<Instructor>
Shawn Andersson

<Contact>
ri-international@sci.osaka-u.ac.jp (Graduate School of Science, A115)

Back number: English Café 2025, English Café 2024

Note: This information is also available on KOAN.

She was welcomed by Prof. Atsushi Takahashi, Vice Dean and Chair of the International Exchange Committee, and Lecturer Yuri Kamon, a member of the International Exchange Committee, from the Graduate School of Science, as well as Prof. Noriko Okubo and Prof. Mari Shimizu from the Graduate School of Law and Politics. During the meeting, the participants discussed future collaboration.

Building on the academic exchange agreements that our Graduate School of Science and the Graduate School of Law and Politics have concluded with the University of Bremen, the participants introduced the distinctive features of their respective faculties/graduate schools and shared information on the current status of international student acceptance. They also exchanged views on further developing educational and research collaboration.

It was also noted that Japanese can be studied at the University of Bremen’s Language Center and that these courses are very popular. In addition, it was shared that our Graduate School of Science is currently hosting two exchange students from the University of Bremen.

Taking this visit as an opportunity, we will further strengthen cooperation between the two universities and promote international research exchange and human resource development.

[Visitor]
Dr. Mandy Boehnke
（Vice President for International Affairs, Academic Qualification, and Diversity, University of Bremen）

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Now, researchers from Japan have found an overlapping two-factor system that plays an important role in controlling when and how these cells differentiate. In a study published this month in Cell Reports, researchers from The University of Osaka have revealed that two proteins with very similar functions are key regulators of early steps in cellular development and maturation.

Embryonic stem cells can develop into all the different types of cells present in the adult body, from brain cells to liver cells, through a process called differentiation. This process is tightly regulated by activating and repressing factors that bind to the promoters of developmental genes to maintain them in a ‘poised’ state, where these genes can either be switched on or kept off as needed.

“A key mechanism for inhibiting the expression of genes associated with stem cell differentiation involves repressor complexes such as CoREST,” says lead author, Takamasa Ito. “However, it remains unclear how CoREST-mediated repression is stably maintained and which other factors help in repressing expression of these genes.”

To explore this, the researchers tested the role of two proteins, RLF and ZFP292, which previous studies had suggested may help regulate stem cell gene expression. They looked at where these factors bound themselves across the genome and deleted these factors, both individually and together, to determine the effect on gene expression.

“The results were very striking,” explains senior author, Chikashi Obuse. “We found that RLF and ZFP292 play virtually the same role, in that they stabilize the CoREST complex at gene promoters in embryonic stem cells to repress gene expression.”

The presence of either RLF or ZFP292, or both together, at these promoters prevented stem cells from drifting toward differentiation. When these proteins were lost, promoters that were normally repressed became active, leading to the expression of genes associated with differentiation.

“Our results show that RLF and ZFP292 modulate the activity of the CoREST complex to carefully control gene expression in stem cells,” says Ito.

These findings may lead to the development of new techniques for maintaining stem cell quality for research and clinical applications. They also help advance our understanding of diseases caused by dysregulated gene expression and could potentially be applied to develop new treatments.

Overview of the study.
Left: In wild-type cells, RLF/ZFP292 support the proper function of the CoREST complex, leading to the removal of active histone marks and preventing excessive expression of differentiation-associated genes.
Right: In the absence of RLF/ZFP292, CoREST complex function is impaired, resulting in an increase in active histone marks and elevated expression of differentiation-associated genes. Consequently, the undifferentiated state cannot be maintained, and cells undergo differentiation.

The article, “RLF/ZFP292 stabilize CoREST-linked LSD1 engagement at bivalent promoters to safeguard pluripotency,” was published this month in Cell Reports at DOI: https://doi.org/10.1016/j.celrep.2026.117293

Related links

• Department of Biological Sciences, Laboratory of Genome Structure and Function

• Eurkalert!
• AlphaGalileo
• Asia Research News
• ResOU（Research at Osaka University）website

A total of 18 participants attended (7 undergraduate students from the School of Science, 9 graduate students from the Graduate School of Science, 1 undergraduate and 1 graduate student from other schools.). The workshop provided an intensive learning opportunity for participants from a wide range of disciplines and academic levels, covering the full process from AI fundamentals to data collection, training, and implementation.

On the first day, participants learned the basics of AIoT and edge AI, including the fundamental concept of on-device inference, and then proceeded with the setup of the AMB82-mini. They worked on introductory tasks such as audio classification and image classification, and also learned about recent trends and demonstrations in the fields of vision and audio.

On the second day, the program focused on the data preparation process required for implementation, including data collection using the device. In the final session, participants implemented their systems on mini cars and took part in a time-trial race. The event concluded with a lively atmosphere, as participants cheered and compared the different behaviors of the cars.

We would like to express its sincere gratitude to the faculty members and student tutors from NTNU for their invaluable cooperation and support in making this workshop possible.

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They were welcomed by Prof. Tadashi Kondo, Dean of the Graduate School of Science; Prof. Takashi Kubo, Vice Dean; Prof. Atsushi Takahashi, Vice Dean and Chair of the International Exchange Committee; and Lecturer Yuri Kamon, a member of the International Exchange Committee. During the meeting, the participants exchanged views on future collaboration and on a joint symposium scheduled to be held at the University of Osaka in October this year.

In the afternoon of the same day, a research presentation session was held, featuring presentations by two NSYSU faculty members and four students interested in the Double Degree Program (DDP). Faculty members from our Graduate School in related fields also attended, and the session provided a meaningful opportunity for academic exchange through lively questions and discussion. In addition, a laboratory tour was organized after the session, helping the visitors deepen their understanding of our research environment.

Building on the discussions during this visit, we will continue preparations for the successful joint symposium and further strengthen the cooperative relationship between the two universities.

【visitors】
Prof. Jyh-Tsung Lee, Dean, the College of Science
Prof. May-Ru Chen, Associate Dean, the College of Science
Associate Prof. Cheng-Chau Chiu, Associate Vice President for Academic Affairs
Assistant Prof. Chung-Hsin Yang, Assistant Professor, the College of Science
Prof. Toshio Kasai, the College of Science

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