APPL1 as an important regulator of insulin and adiponectin-signaling pathways in the PCOS: A narrative review.

Adaptor protein containing a PH domain, PTB domain and leucine zipper motif 1 (APPL1) plays a central role as the main contributing factor in the adiponectin and insulin signaling. This review aims to discuss previous and recent findings concerning the role of APPL1 in the polycystic ovary syndrome (PCOS) patients with conclusions regarding more efficient therapeutic approaches. A literature review was performed in PubMed, Web of Science, ScienceDirect, Scopus, and Google Scholar from August 1999 to May 2020. This study reveals that APPL1 has a key role in adiponectin, insulin, and follicle-stimulating hormone signaling pathways occurring within the ovaries. Recent studies in mouse model systems have indicated that APPL1 can prevent diabetes, endothelial disorders, and insulin resistance. In contrast, APPL1 deficiency can lead to the metabolic and vascular disorders. APPL1 due to its potential roles in different signaling pathways might be suggested as a novel diagnostic and therapeutic option for prediction of ovarian dysfunctions and treatment of reproductive disorders, especially PCOS.