KLF4 regulates FAM3A to promotes angiotensin II-induced proliferation and migration of vascular smooth muscle cells through the PI3K/AKT signaling pathway.

BACKGROUND

Hypertension, a major cause of cardiovascular disease, is linked to vascular remodeling, which is influenced by phenotypic changes in vascular smooth muscle cells (VSMCs). Studies have shown that KLF4 influences vascular remodeling by promoting VSMC dedifferentiation, increasing proliferation, and enhancing inflammatory responses, while FAM3 may play a key role in VSMC migration and proliferation. Angiotensin II (Ang II) contributes to remodeling, but the mechanisms are unclear.

METHODS

Ang II was used to stimulate VSMCs in order to evaluate the expression levels of KLF4 and FAM3A. EdU assays, transwell and scratch wound healing assays measured proliferation and migration. KLF4 knockdown and overexpression experiments were performed to examine the effects on FAM3A expression and VSMC behavior. Western blotting was conducted to analyze protein expression levels of KLF4, FAM3A, and PI3K/AKT signaling components. Bioinformatics analysis was used to predict KLF4 binding sites on the FAM3A promoter. Luciferase and CHIP assays confirmed regulation.

RESULTS

Ang II stimulation increased VSMC proliferation, migration, and the expression of KLF4 and FAM3A. Knockdown of KLF4 reduced Ang II-induced proliferation and migration of VSMCs, accompanied by decreased FAM3A expression. Conversely, overexpression of KLF4 enhanced FAM3A levels, promoting VSMC proliferation and migration. Bioinformatics, luciferase reporter assays and CHIP assay confirmed that KLF4 directly binds to the FAM3A promoter. FAM3A knockdown inhibited Ang II-induced VSMC proliferation and migration by reducing PI3K/AKT pathway activation, whereas FAM3A overexpression reversed the inhibitory effects of KLF4 knockdown.

CONCLUSION

KLF4 transcriptionally regulates FAM3A, modulating Ang II-induced VSMC proliferation and migration through the PI3K/AKT signaling pathway.