Recent advances in gene delivery for melanocyte-associated disorders.

Melanocytes are cells that produce the pigment melanin, which provides color to the skin, eyes, and hair. Dysregulation in melanocyte function, viability, or differentiation can result in melanocyte-associated disorders that can be broadly classified based on etiology as melanocyte hyperproliferation and hyperactivation, defects in melanin synthesis, inflammatory alterations in melanin production/trafficking, melanocyte destruction, and defects in melanocyte migration. While most of these disorders are of benign origin, the cosmetic implications of these conditions are associated with significant psychosocial burden and cultural stigma, having a significant impact on affected individuals. These conditions are primarily driven by changes in underlying gene expression (both at the genetic and epigenetic levels). Targeting the underlying genetic and transcriptomic changes in melanocyte-associated disorders using gene replacement (plasmid DNA, mRNA), gene knockdown (siRNA), or miRNA replacement (miRNA) presents a promising strategy for developing treatments for these conditions. The delivery of naked nucleic acid molecules is challenging, and lipid- and polymer-based particles have been widely evaluated for the successful delivery of biologically active nucleic acids to the melanocytes. This review provides an overview of melanocyte-associated pigmentary disorders and their underlying genetic factors and examines current preclinical and clinical efforts using non-viral polymeric and lipid-based delivery systems for plasmid DNA and RNA-based therapeutics.