Embryonic Lethal Abnormal Visual-Like Protein 1 Aggravates Caerulein-Induced AR42J Cell Injury and Macrophage M1 Polarization to Accelerate Acute Pancreatitis by Upregulating TRAF6.

Abstract

Tumor necrosis factor receptor-associated factor 6 (TRAF6) has been found to promote the progression of acute pancreatitis (AP). However, its underlying molecular mechanisms in AP need to be further revealed. Caerulein-induced AR42J cells were used to construct AP cell models. Cell viability and apoptosis were measured by Cell Counting Kit 8 assay and flow cytometry. Levels of inflammatory factors and oxidative stress-related markers were assessed. The medium of AR42J cells was collected for coculturing RAW264.7 cells. Macrophage marker CD86⁺ cell rates were checked with flow cytometry. The levels of TRAF6, embryonic lethal abnormal visual-like protein 1 (ELAVL1), and inducible nitric oxide synthase (iNOS) were examined by Western blot or quantitative real-time polymerase chain reaction. RNA immunoprecipitation assay was performed to evaluate the interaction between ELAVL1 and TRAF6. TRAF6 mRNA stability was tested using actinomycin D treatment. Caerulein treatment suppressed viability, induced AR42J cell apoptosis, inflammation, oxidative stress, and accelerated macrophage M1 polarization. TRAF6 downregulation could alleviate caerulein-induced AR42J cell injury and macrophage M1 polarization. ELAVL1 interacted with TRAF6 to stabilize its expression. Meanwhile, ELAVL1 knockdown relieved caerulein-induced AR42J cell injury and macrophage M1 polarization, while these effects were abolished by TRAF6 overexpression. TRAF6, stabilized by ELAVL1, promoted caerulein-induced AR42J cell injury and macrophage M1 polarization, suggesting that it might accelerate AP9 progression.