Systematic Review of Genetic Substrate Reduction Therapy in Lysosomal Storage Diseases: Opportunities, Challenges and Delivery Systems

Abstract

Background: Genetic substrate reduction therapy (gSRT), which involves the use of nucleic acids to downregulate the genes involved in the biosynthesis of storage substances, has been investigated in the treatment of lysosomal storage diseases (LSDs).

Objective: To analyze the application of gSRT to the treatment of LSDs, identifying the silencing tools and delivery systems used, and the main challenges for its development and clinical translation, highlighting the contribution of nanotechnology to overcome them.

Methods: A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines was performed. PubMed, Scopus, and Web of Science databases were used for searching terms related to LSDs and gene-silencing strategies and tools.

Results: Fabry, Gaucher, and Pompe diseases and mucopolysaccharidoses I and III are the only LSDs for which gSRT has been studied, siRNA and lipid nanoparticles being the silencing strategy and the delivery system most frequently employed, respectively. Only in one recently published study was CRISPR/Cas9 applied to treat Fabry disease. Specific tissue targeting, availability of relevant cell and animal LSD models, and the rare disease condition are the main challenges with gSRT for the treatment of these diseases. Out of the 11 studies identified, only two gSRT studies were evaluated in animal models.

Conclusions: Nucleic acid therapies are expanding the clinical tools and therapies currently available for LSDs. Recent advances in CRISPR/Cas9 technology and the growing impact of nanotechnology are expected to boost the clinical translation of gSRT in the near future, and not only for LSDs.

Fig. 1

Substrate reduction therapy concept. SRT substrate reduction therapy. Created with BioRender.com

Fig. 2

PRISMA flow diagram of the selection process of the records from the three databases. WoS web of science, LSD lysosomal storage disease, gSRT genetic substrate reduction therapy

Fig. 3

Target enzymes of LSDs metabolic pathways addressed by gene substrate reduction therapy (gSRT). A Application in Gaucher disease (GD) and Fabry disease (FD). B Application in Pompe disease (PD). C Application in MPSs I and III. GCS glucosylceramide synthase, Gb3S Gb3 synthase, α-Gal A α-Galactosidase A, GYS glycogen synthase, GYG, glycogenin, MPS mucopolysaccharidosis, Xyl xylose, Gal galactose, GlucAc glucuronic acid, XYLT O-Xylosyltransferase, GalT-1/2 β-galactosiltransferase 1/2, GlcA-T1 glucosyltransferase 1, EXTL2/3 EXT-like protein 2 and 3, EXT1/3 glycosiltransferase EXT1 and EXT3

Fig. 4

Silencing and gene-editing strategies used for gSRT in LSDs. siRNA short interfering RNA, shRNA short hairpin RNA, RNA Pol II/III RNA polymerase II/III, RISC RNA-induced silencing complex, mRNA messenger RNA, ASO antisense oligonucleotide, CRISPR/Cas9 clustered regularly interspaced short palindromic repeats, sgRNA single guide RNA, PAM sequence protospacer adjacent motif. Created with BioRender.com

Fig. 5

Intracellular barriers for nucleic acid delivery systems. shRNA short hairpin RNA, ASO antisense oligonucleotide, CRISPR/Cas9 clustered regularly interspaced short palindromic repeats/Cas9, siRNA small interfering RNA. Created with BioRender.com