Keratin 79 is a PPARA target that is highly expressed by liver damage

Keratins are key structural proteins found in skin and other epithelial tissues. Keratins also protect epithelial cells from damage or stress. Fifty-four human keratins were identified and classified into two families, type I and type II. Accumulating studies showed that keratin expression is highly tissue-specific and used as a diagnostic marker for human diseases. Notably, keratin 79 (KRT79) is type II cytokeratin that was identified as regulator of hair canal morphogenesis and regeneration in skin, but its role in liver remains unclear. KRT79 is undetectable in normal mouse but its expression is significantly increased by the PPARA agonist WY-14643 and fenofibrate, and completely abolished in Ppara-null mice. The Krt79 gene has functional PPARA binding element between exon 1 and exon 2. Hepatic Krt79 is regulated by HNF4A and HER2. Moreover, hepatic KRT79 is also significantly elevated by fasting-and high-fat diet -induced stress, and these increases are completely abolished in Ppara-null mice. These findings suggest that hepatic KRT79 is controlled by PPARA and is highly associated with liver damage. Thus, KRT79 may be considered as a diagnostic marker for human liver diseases.(c) 2023 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

Keratins are important structural proteins that play a protective role in skin and other epithelial tissues. They are highly tissue-specific and can be used as diagnostic markers for human diseases. KRT79, a type II cytokeratin, has been identified as a regulator of hair canal morphogenesis and regeneration in skin, and its role in the liver is still unclear. However, recent studies suggest that hepatic KRT79 is controlled by PPARA and is associated with liver damage, making it a potential diagnostic marker for human liver diseases.