The Role of Kruppel‐like Factor 6 in Prolidase Regulation

Abstract

Prolidase, also known as peptidase D (PEPD), is a hydrolase that cleaves dipeptides containing C-terminal proline or hydroxyproline. These dipeptides are generated largely during collagen turnover, therefore prolidase catalysis is an essential rate-limiting step during collagen biosynthesis. Consequently, prolidase plays a significant role in collagen metabolism, matrix remodeling, and wound healing. Defective wound healing is one of the hallmarks of Prolidase Deficiency, a rare autosomal recessive disorder characterized by the excretion of prolidase substrates in the urine. Although prolidase is implicated in wound healing, its molecular and cellular regulation remains understudied. Our initial in silico analysis of the PEPD promoter (PEPDpro) identified key regulatory elements upstream of the transcription start site. We identified Kruppel-like factor 6 (KLF6), a zinc-finger transcription factor associated with vascular injury, wound healing, and collagen metabolism. To study the interaction between KLF6 and prolidase, we amplified the promoter from the human genome and inserted it into a luciferase reporter construct. Our preliminary data demonstrate that KLF6 enhances PEPD promoter activity in a dose-dependent manner. Additionally, KLF6 is regulated by transforming growth factor β1 (TGFβ1), and our data illustrate that TGFβ1 drives PEPD promoter activity. These results will generate new knowledge on the molecular regulation of prolidase and aid in developing therapeutic approaches to regulate prolidase expression in various physiological and pathological conditions such as wound healing.