SEONGNAM, South Korea, Aug. 3, 2023 /PRNewswire/ — Rznomics developed a novel platform technology termed ‘self-circularized RNA structure’ that can efficiently and simply generate circular RNA and overcome the limitations of existing technology. Rznomics published an article regarding its development strategy and efficacy in the journal ‘Molecular Therapy Nucleic Acids.’
Since the success of the COVID-19 vaccine, mRNA technology has been studied with great interest in various fields, such as vaccines and therapeutics. However, conventional linear mRNA is vulnerable to nucleases, and patent-protected modified nucleic acids need to be used for efficient protein expression with the reduction of unwanted immune responses.
To overcome the drawbacks of the conventional linear RNAs mentioned above, circular RNA structure technology has recently attracted attention. Circular RNA (circRNA) has a closed structure, so it has great stability against nucleases, and it has been reported that there are no influences on unwanted immune responses and protein expression without using the modified nucleotides. Therefore, if it is commercialized, circRNA vaccines or therapeutics will potentially be more competitive in price and will have the same efficacy equivalent to linear RNA in a smaller amount.
Attracting large-scale investments, a couple of major biotech companies in the U.S. lead the circRNA R&D industry and show the expectations from the market. In the case of one of these companies, they use a circRNA manufacturing technology based on group I intron ribozyme, called the Permuted Intron-Exon (PIE) method. The PIE method splits the ribozyme, which was used in the cis-splicing reaction to remove the intron and link the flanking exons, into half and connects each half of ribozyme to both ends of the GOI (Gene of interest) to make the circRNA with specific GOI. Since the immaturity stage of the circRNA field, there are rooms for biotech companies to enter the competition. However, to enter the market with competitiveness, the core & innovative platform technology that overcomes the limitations of existing technologies is essential.
Rznomics has developed a new circular RNA manufacturing technology that uses group I intron ribozyme as well. However, the technology is fundamentally different from the PIE method in the circularization mechanism. Rznomics has recently published its own circular RNA technology on line in Molecular Therapy Nucleic Acids (DOI: https://doi.org/10.1016/j.omtn.2023.07.034, Title; Efficient circular RNA engineering by end-to-end self-targeting and splicing reaction using Tetrahymena ribozyme), the official journal of the American Society for Gene and Cell Therapy (ASGCT). Rznomics applied its unique Tetrahymena trans-splicing ribozyme platform technology to effectively convert linear RNA into circular RNA by designing end-to-end self-targeting and splicing (STS) reaction.
As shown in the figure, an RNA construct was designed to connect the GOI at the end of the group I intron ribozyme. In this construct, the target site that can be targeted by ribozyme and IGS (Internal Guide Sequence) that guides the targeted trans-ligation by base-pairing with the target site were designed to locate at both ends to enable the circular RNA formation through a self-circularization reaction.
The most notable point is that in contrast to the PIE method, Rznomics’ circularization technology does not leave traces of non-necessary genetic information in the GOI (Gene of Interest) after the self-circularization reaction. In the case of PIE, the ribozyme needs to connect both ends of the GOI harboring extraneous specific nucleotide sequences to form a circular RNA. Whereas, in the case of STS reaction, the ribozyme leads to self-circularization by designing any target sequence present in GOI to be located at the end of GOI.
Also, Rznomics confirmed that circularization efficiency is comparable to the efficiency of the PIE method. In addition, due to the nature of the STS reaction, it is possible to establish various optimization strategies to increase the self-circularization efficiency, unlike the PIE method. It is considered that the self-circularization efficiency decreases as the length of the gene of interest. However, in the case of Rznomics technology, it is possible to screen an optimal target sequence that maximizes the efficacy of self-circularization. Rznomics stated that, through the STS-based reaction, long RNA such as human dystrophin RNA (11,265 nucleotides) was successfully self-circularized.
Moreover, a self-circularization reaction occurs simultaneously during in vitro transcription which is the process of synthesizing RNA. Therefore, the purification process can be directly initiated without any additional steps of the process. In the published paper, Rznomics also mentioned a method for purifying the circRNA using the IP-RP HPLC technique. The purified circRNA with unmodified nucleotides enabled more efficient and sustained protein expression without unwanted immune responses, compared with linear RNA with modified nucleotides.
This research was conducted with the support of the Ministry of Science & ICT and the National Research Foundation of Korea. The ‘Self-circularization RNA structure and Platform technology’ is a patent granted in South Korea (10-2442946) and has been applied in the U.S. and major countries.
About Rznomics
As a biopharmaceutical company founded in the laboratory of Professor Seong-Wook Lee, Dankook University Department of Bioconvergence Engineering, Rznomics is researching with the goal of developing new RNA-based gene therapeutic bio-drugs for cancer and incurable diseases. Rznomics’ core platform technology is based on an RNA replacement enzyme, known as trans-splicing ribozyme, which can edit target RNA through simultaneous destruction and repair (and/or reprogramming) to yield the desired therapeutic RNA, thus, selectively inducing therapeutic gene activity in cells expressing the target RNA.
Rznomics’ lead candidate (RZ-001) is a treatment for Hepatocellular Carcinoma & Glioblastoma (Phase 1/2a IND approval from both in South Korea and in the U.S.), with other treatments for Alzheimer’s disease and hereditary retinal dystrophy (RD). For more information, please visit www.rznomics.com.
Contact
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