Drug development for neglected ultra-rare diseases of no commercial interest: Challenges and opportunities.

Ultra-rare diseases, particularly those that affect a few hundred patients worldwide, are of little commercial interest to the pharmaceutical industry. Patient-led organizations have made remarkable progress in funding the early-stage, academic development of therapies for such neglected ultra-rare conditions. But the long and difficult path to translate most academic proof-of-concept studies into approved medicines means that very few therapies ever reach patients.

Viral vector-mediated gene replacement reduces cerebellar dysfunction in the rat model of Christianson syndrome.

Background: Christianson syndrome (CS) is an x-linked recessive neurodevelopmental and neurodegenerative condition characterized by severe intellectual disability, cerebellar degeneration, ataxia, and epilepsy. Mutations to the gene encoding NHE6 are responsible for CS, and we recently demonstrated that a mutation to the rat gene causes a similar phenotype in the spontaneous rat model, which exhibits cerebellar degeneration with motor dysfunction. In previous work, we used the PhP.

Delivery of siRNAs to Dendritic Cells Using DEC205-Targeted Lipid Nanoparticles to Inhibit Immune Responses.

Due to their ability to knock down the expression of any gene, siRNAs have been heralded as ideal candidates for treating a wide variety of diseases, including those involving "undruggable" targets. However, the therapeutic potential of siRNAs remains severely limited by a lack of effective delivery vehicles. Recently, lipid nanoparticles (LNPs) containing ionizable cationic lipids have been developed for hepatic siRNA delivery.

Evolutionarily conserved genetic interactions with budding and fission yeast MutS identify orthologous relationships in mismatch repair-deficient cancer cells.

Background: The evolutionarily conserved DNA mismatch repair (MMR) system corrects base-substitution and insertion-deletion mutations generated during erroneous replication. The mutation or inactivation of many MMR factors strongly predisposes to cancer, where the resulting tumors often display resistance to standard chemotherapeutics. A new direction to develop targeted therapies is the harnessing of synthetic genetic interactions, where the simultaneous loss of two otherwise non-essential factors leads to reduced cell fitness or death.

Aptamer-targeted antigen delivery.

Effective therapeutic vaccines often require activation of T cell-mediated immunity. Robust T cell activation, including CD8 T cell responses, can be achieved using antibodies or antibody fragments to direct antigens of interest to professional antigen presenting cells. This approach represents an important advance in enhancing vaccine efficacy.

Optimizing siRNA delivery to the genital mucosa.

RNA interference (RNAi) describes a highly conserved pathway, present in eukaryotic cells, for regulating gene expression. Small stretches of double-stranded RNA, termed small interfering RNAs (siRNAs), utilize this pathway to bind homologous mRNA, resulting in site-specific mRNA cleavage and subsequent protein degradation. The ubiquitous presence of the RNAi machinery, combined with its specificity and efficacy, makes it an attractive mechanism for reducing aberrant gene expression in therapeutic settings.

siRNA-based topical microbicides targeting sexually transmitted infections.

Sexually transmitted infections (STIs) are a major cause of morbidity and mortality worldwide. Although a vaccine is available for HPV, no effective vaccines exist for the HIV-1 and HSV-2 viral pathogens, and there are no cures for these infections. Furthermore, recent setbacks in clinical trials, such as the failure of the STEP trial to prevent HIV-1 infection, have emphasized the need to develop alternative approaches to interrupt the transmission of these pathogens.