Science

Alternative Splicing

The human genome project revealed that humans have far fewer genes than expected, and that most human proteins arise through alternative RNA splicing, a process that produces multiple mRNA and protein isoforms from a single gene.

For the majority of genes, alternative splicing produces multiple proteins with different functions. Alternative splicing pathways are affected in a number of diseases such that disease-related protein isoforms are over-produced and the desirable forms are decreased. Ercole's technology enables manipulation of splicing to restore production of desired proteins and is therefore a novel therapeutic platform.

Splice Switching Oligonucleotides (SSOs) are macromolecular drugs central to Ercole's technology. SSOs direct alternative splicing by forcing the splicing machinery towards desired pathways.

Alternative RNA splicing. DNA contains genetic information that codes for protein. This information is fragmented into exons (colored boxes), which are interrupted by non-coding fragments called introns, (white boxes). The DNA is transcribed into pre-mRNA, in which the coding exons remain interrupted by introns. By the process of alternative splicing, the introns are removed and the exons spliced together in different combinations, generating different messenger RNAs (mRNA) that are translated into related proteins with distinct functions.

How SSOs Work
Ercole exploits pre-mRNA splicing to control gene function to produce a therapeutic benefit.

SSOs are designed to block disease related splicing pathways and simultaneously promote the production of desirable mRNAs. The SSO action thus prevents the production of disease related proteins, in favor of increased levels of therapeutic proteins.

Competing RNA-targeted technologies such as antisense molecules, ribozymes and siRNA can only down-regulate levels of undesirable mRNA.

Ercole's drug discovery platform enables specific control of gene function. In the disease state, a form of protein containing a undesirable, disease related exon (green box, left panel) is produced. SSOs block inclusion of the targeted exon thereby forcing the splicing machinery to select a different pathway, producing a therapeutic protein that lacks the harmful exon. Importantly, the SSO simultaneously upregulates expression of the therapeutic protein, while simultaneously downregulating expression of the disease-related protein.

Advantages of SSOs
Ercole's Splice Switching Drugs (SSOs) upregulate expression of a therapeutic gene product while simultaneously decreasing the expression of a disease-related product.

The dual mechanism of action confers a higher potency and broader applicability to Ercole's SSOs compared to other RNA-targeted drugs (e.g. antisense, ribozymes, siRNA).

SSOs are based on the latest generations of oligonucleotide chemistries, yielding high potency and specificity, predictable and favorable pharmacokinetics, low toxicity, and routine manufacturing.

SSO's are a platform technology that allows the advancement from gene sequence to drug candidate in a fraction of the time and expense associated with small molecule and protein-based drug development.

Small molecule drugs target only 10% of human proteins. Ercole's SSOs may be targeted to any of the 75% of human genes that undergo alternative splicing.