RNA interference (RNAi) is a gene-silencing technique that inhibits gene expression by causing the intracellular degradation of mRNA molecules. Since first reported in 1998, RNAi has sparked a revolution in molecular biology and has been employed in a myriad of biological contexts for the systematic evaluation of gene function. The ability to selectively regulate the activity of specific genes within a given biological location represents a methodology by which researchers can upregulate or downregulate protein expression.
Controlling gene expression through RNAi typically involves the use of double-stranded RNA molecules that are between 20–25 base pairs long. Dubbed “small interfering” or “silencing” RNA (siRNA), these oligonucleotides interfere with native gene expression by binding to complementary strands of messenger RNA (mRNA) to form complexes that are then degraded by the cell’s natural machinery before protein translation can occur. While the exact mechanism of siRNA-mediated gene suppression is complex, siRNAs can potentially be used to selectively disrupt the expression of any gene within a given genome. Recently, RNAi-based approaches have been gaining traction as promising modalities to inhibit viral infection and cancer proliferation in humans. However, while targeted gene suppression by siRNA has shown promising clinical results for certain applications, consistent delivery of siRNA to specific targets in vivo has remained a difficult challenge.
The potential impact that siRNA technology can have on the multi- billion dollar skin care market cannot be overstated. The epidermis is the body’s largest organ and, by some assessments, the most accessible when using topical delivery agents. Overall, the field of gene therapy has been plagued by inefficient delivery of potent gene-silencers and off-target effects, drastically limiting the development of therapeutic siRNAs. Despite these setbacks, this situation represents a unique opportunity for the cosmetic scientist to develop revolutionary products that are capable of preventing or treating debilitating skin disorders.