ZNF469 is a profibrotic regulator of extracellular matrix in hepatic stellate cells

Abstract

Activation of quiescent hepatic stellate cells (HSCs) into proliferative myofibroblasts drives extracellular cellular matrix (ECM) accumulation and liver fibrosis; nevertheless, the transcriptional network that promotes such a process is not completely understood. ZNF469 is a putative C2H2 zinc finger protein that may bind to specific genome sequences. It is found to be upregulated upon HSC activation; however, the molecular function of ZNF469 is completely unknown. Here, we show that knockdown of ZNF469 in primary human HSCs impaired proliferation, migration, and collagen production. Conversely, overexpression of ZNF469 in HSCs yielded the opposite results. Transforming growth factor-β 1 promoted expression of ZNF469 in a Smad3-dependent manner, where the binding of Smad3 was confirmed at the ZNF469 promoter. RNA sequencing data of ZNF469-knockdown HSCs revealed the ECM-receptor interaction, which provides structural and signaling support to cells, was the most affected pathway, and significant downregulation of various collagen and proteoglycan genes was observed. To investigate the function of ZNF469, we cloned a full-length open reading frame of ZNF469 with an epitope tag and identified a nuclear localization of the protein. Luciferase reporter and chromatin immunoprecipitation assays revealed the presence of ZNF469 at the promoter of ECM genes, supporting its function as a transcription factor. Analysis of human fibrotic and cirrhotic tissues showed increased expression of ZNF469 and a positive correlation between expression levels of ZNF469 and ECM genes. Moreover, this observation was similar in other fibrotic organs, including the heart, lung, and skin, suggesting that myofibroblasts from various origins generally require ZNF469 to promote ECM production. Together, this study is the first to reveal the role of ZNF469 as a profibrotic factor in HSCs and suggests ZNF469 as a novel target for antifibrotic therapy.