Exploring the Roles of Gut Microbiota-Derived Peptidoglycan Fragments (PGNs) as Signalling Molecules in Host Biology
Event details
| Date | 19.09.2025 |
| Hour | 14:00 › 15:00 |
| Speaker | Prof. Yuan Qiao, School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University (NTU), Singapore |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
BIOENGINEERING SEMINAR
Abstract:
Gut microbiota-derived peptidoglycan fragments (PGNs) are key signaling molecules that significantly influence host biology, mediating bacterial-host and bacterial-fungal crosstalk. Yet the exact structures of natural PGNs in the host have not been fully elucidated. With a robust LC-HRMS/MS analytical platform, we profiled natural PGN subtypes in the host gut. We established that the disaccharide GlcNAc-MurNAc (GM), a prominent PGN motif, acts as a novel TLR4 agonist and protects against colonic inflammation in the colitis mouse model. These results provide valuable insights into the role of natural PGNs in maintaining host intestinal homeostasis.
In addition, gut microbiota-derived PGNs are potent inducers of invasive hyphal growth in Candida albicans, a major human fungus. Recently, we not only identified the long-sought PGN transporter in C. albicans but also demonstrated that Ssy1 acts as the extracellular sensor for PGNs and is crucial for mediating C. albicans invasive growth. Deletion of Ssy1 renders C. albicans unresponsive to beta-lactam-induced PGN storms in the mouse gut, significantly reducing its virulence and systemic dissemination. Our findings establish Ssy1 as a potential anti-virulence target for preventing PGN-induced invasive growth of C. albicans in hosts.
Bio:
Yuan Qiao completed her undergraduate studies in chemistry at Bryn Mawr College (USA) in 2010, where she did synthetic chemistry research with Dr. Bill Malachowski. After spending a year working on antimicrobial polymers in the lab of Dr. Yi-Yan Yang at IBN in Singapore, Yuan became interested in using chemical tools to study biological problem, and joined the Chemical Biology graduate program at Harvard University in 2011. In the labs of Prof. Dan Kahne and Prof. Suzanne Walker at Harvard, Yuan focused on characterizing the enzymes that make bacterial peptidoglycan, an essential component of the bacterial cell wall that is an excellent antibiotic target. Her graduate research solved several key problems in the field and established novel tools for new antibiotic discovery. Since 2017, Yuan joined Prof. Yue Wang's lab in IMCB, Singapore, where she was interested in understanding the role of bacterial peptidoglycan in bacterial-fungal interaction. Yuan was a recipient of the A*STAR National Science Scholarship in Singapore (2007-2016). She started as an Assistant Professor in the Chemistry and Chemical Biology Division in SPMS NTU in Nov. 2019.
Zoom link for attending remotely: https://epfl.zoom.us/j/69851372962
Instructions for 1st-year Ph.D. students planning to attend this talk, who are under EDBB’s mandatory seminar attendance rule:
IN CASE you cannot attend in-person in the room, please make sure to
Abstract:
Gut microbiota-derived peptidoglycan fragments (PGNs) are key signaling molecules that significantly influence host biology, mediating bacterial-host and bacterial-fungal crosstalk. Yet the exact structures of natural PGNs in the host have not been fully elucidated. With a robust LC-HRMS/MS analytical platform, we profiled natural PGN subtypes in the host gut. We established that the disaccharide GlcNAc-MurNAc (GM), a prominent PGN motif, acts as a novel TLR4 agonist and protects against colonic inflammation in the colitis mouse model. These results provide valuable insights into the role of natural PGNs in maintaining host intestinal homeostasis.
In addition, gut microbiota-derived PGNs are potent inducers of invasive hyphal growth in Candida albicans, a major human fungus. Recently, we not only identified the long-sought PGN transporter in C. albicans but also demonstrated that Ssy1 acts as the extracellular sensor for PGNs and is crucial for mediating C. albicans invasive growth. Deletion of Ssy1 renders C. albicans unresponsive to beta-lactam-induced PGN storms in the mouse gut, significantly reducing its virulence and systemic dissemination. Our findings establish Ssy1 as a potential anti-virulence target for preventing PGN-induced invasive growth of C. albicans in hosts.
Bio:
Yuan Qiao completed her undergraduate studies in chemistry at Bryn Mawr College (USA) in 2010, where she did synthetic chemistry research with Dr. Bill Malachowski. After spending a year working on antimicrobial polymers in the lab of Dr. Yi-Yan Yang at IBN in Singapore, Yuan became interested in using chemical tools to study biological problem, and joined the Chemical Biology graduate program at Harvard University in 2011. In the labs of Prof. Dan Kahne and Prof. Suzanne Walker at Harvard, Yuan focused on characterizing the enzymes that make bacterial peptidoglycan, an essential component of the bacterial cell wall that is an excellent antibiotic target. Her graduate research solved several key problems in the field and established novel tools for new antibiotic discovery. Since 2017, Yuan joined Prof. Yue Wang's lab in IMCB, Singapore, where she was interested in understanding the role of bacterial peptidoglycan in bacterial-fungal interaction. Yuan was a recipient of the A*STAR National Science Scholarship in Singapore (2007-2016). She started as an Assistant Professor in the Chemistry and Chemical Biology Division in SPMS NTU in Nov. 2019.
Zoom link for attending remotely: https://epfl.zoom.us/j/69851372962
Instructions for 1st-year Ph.D. students planning to attend this talk, who are under EDBB’s mandatory seminar attendance rule:
IN CASE you cannot attend in-person in the room, please make sure to
- send D. Reinhard a note well ahead of time (ideally before seminar day), informing that you plan to attend the talk online, and, during seminar:
- be signed in on Zoom with a recognizable user name (not any alias making it difficult or impossible to identify you).
Practical information
- Informed public
- Free
Organizer
- Prof. Alexandre Persat, Global Health Institute & Institute of Bioengineering
Contact
- [email protected] or Institute of Bioengineering (IBI), Dietrich REINHARD