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bioRxiv · 10.1101/2025.09.25.678210

Expression screening and functional verification of recombinant hirudin from novel chassis cell Chlamydomonas reinhardtii

Feng, L.·Xing, J.·Tian, A.·Wang, W.·Zhang, Y.·Hu, Z.
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Abstract

Hirudin is a potent anticoagulant peptide whose clinical application is limited by scarce natural supplies and the suboptimal activity of recombinant versions from conventional microbial hosts lacking key post-translational modifications. Here, for the first time, we establish the "Generally Regarded as Safe" (GRAS) microalga, Chlamydomonas reinhardtii, as a novel biological chassis for producing fully functional hirudin. Using high-density heterotrophic fermentation, we generated a bioactive lyophilized algal powder suitable for oral delivery. Crucially, the algal-derived hirudin underwent proper tyrosine sulfation--a key modification absent in prokaryotic hosts--conferring exceptionally high thrombin-inhibitory activity (up to 20,000 ATU/mg). When orally administered to a murine thrombosis model, this hirudin-loaded alga demonstrated potent antithrombotic efficacy. It also exhibited a superior safety profile, showing no signs of the thrombocytopenia or bleeding associated with traditional anticoagulants. This study establishes a green, scalable biomanufacturing and oral delivery platform for therapeutics, highlighting transformative potential at the nexus of agricultural bioengineering, functional foods, and biomedicine.

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Feng, L., Xing, J., Tian, A., Wang, W., Zhang, Y., Hu, Z.. 2025-09-26. Expression screening and functional verification of recombinant hirudin from novel chassis cell Chlamydomonas reinhardtii. https://doi.org/10.1101/2025.09.25.678210

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