Knockdown of programmed cell death 4 inhibits endoplasmic reticulum stress in male mice with intracerebral hemorrhage through the phosphoinositide 3-kinase/protein kinase B pathway.

Abstract

BACKGROUND: Pdcd4 is a potential target for intracerebral hemorrhage (ICH) treatment. This research intended to elucidate the mechanism by which Pdcd4 regulates ICH progression. METHODS: Male mice were infected with sh-Pdcd4 lentivirus, followed by injection of bacterial collagenase to establish an ICH model. Subsequent experiments, including brain water content assessment, neurological injury scoring, brain hematoma volume measurement, ELISA, HE staining, immunohistochemistry, Evans blue extravasation assay, and Western blot, were conducted to analyze the role of Pdcd4 in ICH. PI3K inhibitor LY294002 was employed to further investigate the potential mechanisms in vivo. bEnd.3 cells were infected with sh-Pdcd4 in the presence or absence of tunicamycin (an ER stress inducer), followed by hemoglobin treatment to mimic ICH in vitro. The effects of Pdcd4 on endoplasmic reticulum (ER) stress in ICH were evaluated through CCK-8, ELISA, and Western blot assays. RESULTS: Pdcd4 was upregulated in ICH mice, with the highest levels observed at 24 h. Pdcd4 knockdown markedly alleviated brain injury and neuroinflammation, inhibited ER stress, and upregulated PI3K/AKT pathway in ICH mice. These changes were partially reversed by LY294002. In bEnd.3 cells, Pdcd4 levels were significantly increased after hemoglobin treatment. Additionally, Pdcd4 knockdown significantly increased cell viability and inhibited inflammatory factor secretion and ER stress in the ICH group. This phenomenon was partially counteracted by tunicamycin. Furthermore, Pdcd4 knockdown markedly activated the PI3K/AKT pathway in the ICH group. CONCLUSION: Pdcd4 knockdown alleviates ICH through PI3K/AKT pathway-mediated ER stress.