A simple, noninvasive and efficient method for transdermal delivery of siRNA

Abstract

Effective delivery of therapeutic agents is the most challenging hurdle in the use of RNA interference for research and in the clinic. Here, we assessed whether a short synthetic peptide, ACSSSPSKHCG (TD-1), could be transported through rat footpad (follicle-free) skin and efficiently deliver small interfering RNA (siRNA) to knock down a target gene. Fluorescence microscopy revealed that topical co-administration of FITC-labeled TD-1 and FAM-labeled siRNA distributed uniformly from the epidermis to the subcutaneous tissue of rat footpad skin. Transmission electron microscopy revealed the absence of cell-cell junctions and enlarged spaces between epithelial cells in the TD-1-treated footpad skin. TD-1 delivery of anti-GAPDH siRNA significantly reduced the level of GAPDH in 72 h. TD-1 can create a transient opening in non-follicle rat skin for delivery of siRNA and reveal a novel mechanism of transdermal delivery of TD-1 and siRNA into the epidermis for gene knockdown. The system might have potential for siRNA delivery in skin for drug therapy.

siRNA-based spherical nucleic acids reverse impaired wound healing in diabetic mice by ganglioside GM3 synthase knockdown

“…SNA constructs are able to penetrate the stratum corneum of intact skin, rapidly enter epidermal and dermal cells, and knock down epidermal targets (17). In contrast to SNAs, other topical siRNAbased therapies require epidermal disruption by physical [e.g., injection, tape stripping (23), laser, or ultrasound] or chemical (e.g., conjugation to peptides or lipoplexes or incorporation into other types of nanoparticle structures, lentiviruses, or gels) means for RNAi penetration through the epidermal barrier and into KCs (24)(25)(26)(27)(28)(29)(30)(31). siRNA SNAs are unique, highly anionic constructs that do not require additional chemical modifications to facilitate transportation through the stratum corneum or entry into cells.…”

Getting Drugs Across Biological Barriers

“…[172–173] TD-1 could enhance the transdermal delivery of insulin when co-administered topically, lowering the serum glucose level in rats. TD-1 peptide has also been used to increase the transdermal delivery of other macromolecules such as hGH, [172, 174] siRNA, [175] botulinum neurotoxin type A (BoNT-A), [176] and CsA. [177] The mechanism by which TD-1 penetrates the SC is unclear.…”

“…[177] The mechanism by which TD-1 penetrates the SC is unclear. [175] TD-1 has been shown to also disrupt tight junctions (see Section 3.1) by interacting with the Na + /K + -ATPase beta-subunit (ATP1B1) on keratinocytes. [178] TD-1 can also enable the transdermal delivery of macromolecular drugs such as insulin through hair follicles.…”

Nucleic acid delivery into skin for the treatment of skin disease: Proofs-of-concept, potential impact, and remaining challenges

“…The first of these peptides discovered using phage-display screening was TD-1 (ACSSSPSKHCG) [42]. Lin et al showed TD-1 could enhance transport of GAPDH siRNA into viable tissue in the skin, as well as subcutaneous tissue, and silence GAPDH expression [43]. Co-incubation of GAPDH siRNA with TD-1 resulted in similar GAPDH expression levels as intradermal injection, while expression levels for both methods of application were significantly less than siRNA applied on the skin without peptide [43].…”