Key result
Systemic rAAV6 vectors expressing shRNAs reduce beta-galactosidase expression up to ~50-fold in mouse striated muscles.
Why the study?
RNAi has potential for therapeutically downregulating dominantly inherited genes, but its ability to reduce gene expression in striated muscles systemically needed evaluation.
Does systemic delivery of rAAV6 expressing shRNAs reduce lacZ expression in striated muscles of ROSA26 mice?
Does systemic delivery of rAAV6 expressing shRNAs reduce lacZ expression in striated muscles of ROSA26 mice?
Systemic delivery of rAAV vectors expressing optimized shRNAs can effectively downregulate target gene expression in striated muscles with reduced toxicity, supporting potential applications for dominantly inherited muscle disorders.
Answers are grounded in this paper and cite their sources.
rAAV-shRNA achieved 30-50-fold muscle gene knockdown in mice; leaves open safe translation to dominant striated muscle disorders.
RNAi has potential for therapeutically downregulating the expression of dominantly inherited genes in a variety of human genetic disorders. Here we used the ROSA26 mouse, which constitutively expresses the bacterial lacZ gene in tissues body wide, as a model to test the ability to downregulate gene expression in striated muscles. Recombinant adeno-associated viral vectors (rAAVs) were generated that express short hairpin RNAs (shRNAs) able to target the lacZ mRNA. Systemic delivery of these rAAV6 vectors led to a decrease of β-galactosidase expression of 30-50-fold in the striated muscles of ROSA26 mice. However, high doses of vectors expressing 21 nucleotide shRNA sequences were associated with significant toxicity in both liver and cardiac muscle. This toxicity was reduced in cardiac muscle using lower vector doses. Furthermore, improved knockdown in the absence of toxicity was obtained by using a shorter (19 nucleotide) shRNA guide sequence. These results support the possibility of using rAAV vectors to deliver RNAi sequences systemically to treat dominantly inherited disorders of striated muscle.
No takes yet. Share an insight, caveat, or question.
Wei et al. (2014) studied ROSA26 mice (constitutively expressing beta-galactosidase). rAAV6 vectors expressing shRNAs (lacZ-shRNA21 or lacZ-shRNA19) vs. Untreated mice or C57BL/6 mice was evaluated on beta-galactosidase expression in striated muscles (30-50-fold decrease). Systemic delivery of rAAV6 vectors expressing shRNAs led to a 30-50-fold decrease of beta-galactosidase expression in the striated muscles of ROSA26 mice.
Synapse has enriched 10 related papers. Consider them for comparative context: