Knockdown of EPSTI1 alleviates lipopolysaccharide-induced inflammatory injury through regulation of NF-κB signaling in a cellular pneumonia model.

Abstract

Although early diagnosis, antibiotic therapies, corticosteroid application, and health care services are conventional managements for pneumonia, antibiotic resistance and adverse reactions remain as limitations for pneumonia treatment. The study attempted to evaluate the potential role of EPSTI1 against pneumonia and reveal its underlying mechanism. Lipopolysaccharide (LPS) (5, 10, and 20 μg/mL) was applied in WI-38 cells to establish the in vitro pneumonia model. Knockdown of epithelial-stromal interaction 1 (EPSTI1) was performed by transfection with EPSTI1 siRNA (siEPSTI1) into LPS-treated cells. Cell Counting Kit-8 assays were implemented to measure cell viability, and apoptotic cells were detected using flow cytometry. Interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) were quantified using enzyme-linked immunosorbent assay (ELISA). Immunoblotting and quantitative real-time polymerase chain reaction (qRT-PCR) were conducted to quantify EPSTI1 expression, and proteins related to nuclear factor κ-light-chain-enhancer of activated B cell (NF-κB) signaling, including p-p65, p65, p-IκBα, and IκBα. EPSTI1 was highly expressed in LPS-treated WI-38 cells. Cell apoptosis was promoted, and cell viability was inhibited after being exposed to LPS. Besides, IL-1β, IL-6, and TNF-α were dramatically upregulated. Knockdown of EPSTI1 restored cell viability, inhibited cell apoptosis, and attenuated expressions of proinflammatory factors. Additionally, knockdown of EPSTI1 visibly decreased the increased ratios of p-p65/p65 and p-IκBα/IκBα induced by LPS. Knockdown of EPSTI1 alleviated inflammatory injury through the inactivation of the NF-κB pathway. These results provided promising management in preventing pneumonia in patients.