ANTI-MIR DELIVERY AND FUNCTION
mRNA expression-profiling methods coupled with statistical techniques that can measure small changes in the expression of
many genes have become powerful tools to further our understanding of the biological role and function of microRNAs. Relying
on the scientific findings that some microRNAs are capable of regulating hundreds of messenger RNAs, studies were performed
in mice to determine anti-miR delivery to different cell types. Mice were treated with a specific anti-miR (intraperitoneal
injection) and multiple cell types were harvested to for mRNA expression studies using Sylamer enrichment analysis (15). Anti-miR
oligonucleotides are distributed to peritoneal macrophages as evidenced by flow cytometry analysis and target gene up-regulation
(see Figure 6). An analysis identifying an overrepresented set of genes associated with a specific anti-miR biological effect
was conducted and a data plot from the isolated macrophages was generated that demonstrated the most up-regulated sets of
genes after anti-miR treatment. P values generated for this dataset suggest statistically significant preferential up-regulation
of genes matched to their target sequence after anti-miR treatment.
Figure 6: Functional drug delivery of anti-miRs in mouse peritoneal macrophages. Flow-cytometry studies (a) and gene-regulation
studies (b) demonstrate the internalization of anti-miR and target engagement in macrophages (Sylamer analysis). Potential
targets containing heptamer 1-7 (GCATTAA) or heptamer 2-8 (AGCATTA) are enriched. X-axis is ranked genes by fold change. Y
axis is -log (P-value enrichment). PBS is Phosphate-buffered saline.
Targeting pathways of human disease with microRNA-based drugs represents a novel and potentially powerful therapeutic approach.
Recent data demonstrate not only that dysregulated microRNAs are associated with and can cause human disease, but that selective
modulation through anti-miR intervention can provide therapeutic benefits. Anti-miR oligonucleotides can be easily administered
through local or parenteral injection routes with sufficient uptake of the agent to achieve sustained target inhibition in
tissues and organs without the need of formulation. Improvements in anti-miR chemical design and pharmacokinetic properties
will allow further exploration of microRNA biology and broaden the utility of microRNA therapeutics.
Kevin Steffy, PhD,* is the global alliance manager, Charles Allerson, PhD, is the associate director of chemistry, and Balkrishen Bhat, PhD, is the senior director of chemistry, all at Regulus Therapeutics, 3545 John Hopkins Ct., San Diego, CA 92121, tel. 858.202.6321,