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

Abstract

Background: 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. Objectives: The study attempted to evaluate the potential role of EPSTI1 against pneumonia and reveal its underlying mechanism. Methods: 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. Results: 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. Conclusions: These results provided promising management in preventing pneumonia in patients.