Kiss1R Identification and Biodistribution Analysis Employing a Western Ligand Blot and Ligand-Derivative Stain with a FITC-Kisspeptin Derivative

Abstract

It is not always easy to establish specific antibodies against receptors. Most receptors are hydrophobic and have complicated three-dimensional structures, making them difficult to use as immunogens. Thus, we developed receptor detection methods with a fluorescein-labeled ligand as an antibody alternative, which we referred to as a western ligand blot (WLB) and ligand derivative stain (LDS). Kisspeptin receptor (Kiss1R) was detected by its ligand. Kiss1R expression was confirmed in eight human cell lines by the WLB and in four pathological tissues by the LDS. Next, Kiss1R was stained by LDS in organs, revealing Kiss1R expression by [⁶⁷ Ga]Ga-DOTA-kisspeptin 10 accumulation. As a result, Kiss1R-expressing cells in each organ could be stained with fluorescein-labeled kisspeptin 14 instead of an antibody and observed by light microscopy. The combination of the WLB and LDS allows identification of receptors in tissues, which can be readily applied to target receptor detection by a synthetic ligand derivative.

Keywords: Antibodies; Imaging agents; Ligand design; Radiopharmaceuticals; Receptors.