Identification of a novel peptide ligand targeting visceral adipose tissue via transdermal route by<i>in vivo</i>phage display

Abstract

To find novel peptide ligands targeting visceral adipose tissue (visceral fat) via transdermal route, in vivo phage display screening was conducted by dermal administration of a phage-peptide library to rats and a peptide sequence, CGLHPAFQC (designated as TDA1), was identified as a targeting ligand to visceral adipose tissue through the consecutive transdermal biopannings. Adipocyte-specific affinity and transdermal activity of the TDA1 were validated in vitro and targeting ability of the dermally administered TDA1 to visceral adipose tissue was also confirmed in vivo. TDA1 was effectively translocated into systemic circulation after dermal administration and selectively targeted visceral adipose tissue without any preference to other organs tested. Fluorescent microscopic analysis revealed that the TDA1 could be specifically localized in the hair follicles of the skin, as well as in the visceral adipose tissue. Thus, we inferred that dermally administered TDA1 would first access systemic circulation via hair follicles as its transdermal route and then could target visceral fat effectively. The overall results suggest that the TDA1 peptide could be potentially applied as a homing moiety for delivery of anti-obesity therapeutics to visceral fat through the convenient transdermal pathway.