Mammoth Biosciences, Inc., a biotechnology company harnessing its proprietary next-generation CRISPR gene editing platform to create potential one-time curative therapies, has officially announced new preclinical research, which reveals proof-of-concept for its NanoCas™ technology, the first ultracompact CRISPR system made to provide efficient extrahepatic editing when delivered systemically using a single adeno-associated viral (AAV) vector.
To understand the significance of such a development, we must take into account a fact that, while editing holds promise for curing genetic diseases, it continues to face delivery challenges that limit its therapeutic applications. You see, all the current methods are restricted to ex vivo approaches or in vivo liver editing. The first-generation CRISPR systems, such as Cas9 and Cas12a, have also been deemed as too large for efficient in vivo delivery via a single AAV vector.
In response, Mammoth’s study relays how discovery, engineering and benchmarking of NanoCas, a novel Cas enzyme approximately one third the size of Cas9, can be easily accommodated within a single AAV vector. At the same, the whole mechanism can also leave ample room for more payload, such as regulatory elements, guide RNAs, or non double strand break editing machinery for techniques like reverse transcriptase editing, base editing, and epigenetic editing.
“We have been focused on discovering and engineering novel ultracompact CRISPR systems at Mammoth and are excited to share the first demonstration of robust in vivo extrahepatic editing in a muscle target with NanoCas with the scientific community,” said Lucas Harrington, Ph.D., CSO and co-founder of Mammoth Biosciences. “At Mammoth, we have always believed in the therapeutic potential of CRISPR, and this study demonstrates that ultra-compact systems can be potent and delivered in a single AAV vector to tissues outside the liver.”
The process of reaching upon the NanoCas system saw functional evaluation of more than 150 candidates, followed by targeted protein engineering to enhance its editing efficiency.
As for the results, they showed that editing efficiency was able to match of first-generation CRISPR systems. Basically, when targeting the PCSK9 gene in mouse liver in vivo, NanoCas successfully showed saturating editing efficiencies of approximately 60%, This aligned with the performance of SaCas9 despite the latter being three-fold larger in size.
Both CRISPR systems, all in all, reduced serum PCSK9 protein to undetectable levels.
Next up, the exercise saw robust single AAV editing across multiple muscle tissues. Simply speaking, NanoCas demonstrated 10% to 40% editing of the dystrophin gene across the quadricep, calf and heart muscle in a humanized mouse model of Duchenne Muscular Dystrophy (DMD), when delivered via a single AAV vector.
Mammoth’s study also facilitated first ever demonstration of single AAV muscle editing in non-human primates. Here, NanoCas achieved in vivo editing efficiencies of up to 30% when targeting dystrophin in the skeletal muscle of cynomolgus macaques.
Not just that, the technology also showed 15% editing across the heart, as compared to 10% with SaCas9. Analysis of liver tissue, on its part, showed minimal off-target editing.
“Potent editing of extrahepatic tissues in vivo has been a roadblock for the gene editing field,” said Trevor Martin, Ph.D., co-founder and chief executive officer, Mammoth Biosciences. “NanoCas’ compact size makes it compatible with a wide range of gene editing modalities – including base editing, reverse transcriptase editing, and epigenetic modification – while still allowing for delivery using a single AAV vector. This study is a major step toward enabling any edit to be made in any cell in vivo, thereby dramatically increasing the number of patients who could benefit from genetic medicines and delivering on the full promise of CRISPR.”
Founded by CRISPR pioneer and Nobel laureate Jennifer Doudna and Trevor Martin, Janice Chen, and Lucas Harrington, Mammoth Biosciences’ rise up the ranks stems from leveraging its proprietary ultracompact CRISPR systems to develop potential long-term curative therapies for patients with life-threatening and debilitating diseases. The company, in essence, is conceiving wholly owned pipeline of potential in vivo gene editing therapeutics and capabilities.
Moving forward, it also has partnerships with leading pharmaceutical and biotechnology companies to broaden the reach of its innovative and proprietary technology platform.
