A novel recombinant alpha-1 antitrypsin (AAT) protein showed promising results as a potential treatment for patients with alpha-1 antitrypsin deficiency (AATD), according to an article recently published in Biotechnology and Bioengineering

During in vitro experiments, recombinant AAT exhibited inhibitory activity comparable to human plasma derivatives with higher oxidation resistance, as reported by Koyuturk and colleagues. 

To produce AAT, the in vitro model used Chinese hamster ovary (CHO) cells and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) technology, followed by the overexpression of human α-2,6-sialyltransferase using a cumate-inducible expression system. Furthermore, the cells were programmed to generate the wild-type protein and a mutated version called mutein with higher resistance to oxidation. 


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The authors tested 6 different promoters, among which cumate-inducible CR5 generated greater quantities of wild-type AAT and mutein of up to 2.1 g/dL and 2.8 g/dL, respectively. N-acetylmannosamine supplementation in the cell cultures promoted protein sialylation. 

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“The recombinant oxidation resistant mutein offers several potential advantages as a therapeutic for patients with [AATD]; it constitutes a sustainable source of therapeutic protein while decreasing the risk of disease transmission and minimizing batch-to-batch heterogeneity,” the authors wrote.

”Moreover, the engineered cell line created here may prove useful for producing other recombinant proteins where fit-for-purpose glycosylation is crucial for their therapeutic efficacy.”

In contrast with previous publications, this experiment yielded unprecedented promising protein concentrations that allow this method to be a potential therapeutic source of AAT. Additionally, the authors hypothesize that cloning isolated cell lines from the CHO pools may generate over 2-fold increases in volumetric levels of AAT. 

These final results are important for patients with AATD since current therapeutic schemes involve human plasma-derived proteins that pose a risk of disease transmission and lack quality and glycosylation consistency between lots while still falling short on antiprotease abilities due to their vulnerability to oxidation.

Reference

Koyuturk I, Kedia S, Robotham A, et al. High‐level production of wild‐type and oxidation‐resistant recombinant alpha‐1‐antitrypsin in glycoengineered CHO cells. Biotechnol Bioeng. Published online May 4, 2022. doi:10.1002/bit.28129