School of Biomedical Sciences cordially invites you to join the following Post-doctoral Fellow (PDF) Seminar:

Date: 23 September 2025 (Tuesday)
Time: 4:00 pm – 5:00 pm
Host: Dr. Xiang Fang & Dr. Yolanda Liu

Seminar will be conducted via zoom, please find the details below -
Zoom link: https://hku.zoom.us/j/97170377147?pwd=wU5lqaTaaSAcRiqDSnWD4ALV6ay24O.1
Meeting ID: 971 7037 7147
Password: 405839

Please register via the below link by 19 September 2025 (Friday):
Registration: https://hku.au1.qualtrics.com/jfe/form/SV_5nkMUypYIc96KVw

Phase-separated peptide coacervates: innovative delivery vehicles for mRNA vaccines
Dr. Chaiyaporn Kuwentrai (Post-doctoral Fellow)
[Supervisor: Professor Jiandong Huang]

Nucleic acid therapeutics, like mRNA vaccines, need effective delivery vehicles. Traditional options, such as lipid nanoparticles and cationic polymers, often cause adverse reactions. We present a six-residue phase-separated peptide that forms coacervates through liquid-liquid phase separation in medium. These coacervates can encapsulate various nucleic acids, including DNA, siRNA, and mRNA, delivering them into cells with efficiency comparable to established methods like lipofectamine and lipid nanoparticles.

In mouse models, mRNA-loaded coacervates resulted in strong protein expression and a favorable safety profile. Notably, the phase-separated peptide formulations produced lower levels of the inflammatory cytokine IL-1β compared to traditional delivery systems, indicating reduced toxicity. Additionally, the coacervates effectively delivered SARS-CoV-2 spike mRNA, eliciting responses similar to the Comirnaty vaccine. In cancer models, peptide-delivered OVA mRNA showed significant anti-tumor effects and improved survival rates. These findings suggest that peptide coacervates are promising for safer and more effective mRNA delivery in gene therapy and vaccines.

Linking functional and structural dendritic spine remodelling during fear learning and extinction in vivo
Dr. Qiyu Todd Zheng (Post-doctoral Fellow)
[Supervisor: Professor Cora Lai]

Structural plasticity of dendritic spines has been observed during different learning paradigms, but how the functional activation of dendritic spines changes with memory processing and how these patterns relate to structural plasticity and dendritic integration remain unclear. Here, using in vivo two-photon microscopy, we perform longitudinal functional and structural imaging of the frontal association cortex in mice subject to fear conditioning and extinction over several days. We show that fear conditioning responsive spines are more likely to be coactive and clustered, and their coactivity positively correlates to shaft dendritic calcium signals. These functional dynamics are consolidated over the following days but importantly are attenuated by fear extinction. Furthermore, we identified a tone discrimination pattern from the dendritic calcium signals which is experience-relevant and correlated to the structural remodelling of dendritic spines. Our findings provide direct evidence linking the functional and structural remodelling of dendritic spines during associative learning in vivo.

All are welcome.