AIM:To investigate the effects of progranulin (PGRN) on the proliferation, apoptosis and inflammatory responses in lipopolysaccharide (LPS)-induced human alveolar epithelial A549 cells and HPAEpiC cells.METHODS:The cells were divided into 4 groups:control group (the normal cultured cells), LPS group [the cells were treated with LPS (10 mg/L)], PGRN+LPS group (the cells were transfected with pcDNA3.1-PGRN plasmids and then treated with LPS), and pcDNA3.1+LPS group (the cells were transfected with pcDNA3.1-EGFP plasmids and then treated with LPS).The cell viability was measured by MTT assay, cell proliferation was measured by BrdU incorporation assay, and cell apoptosis was analyzed by flow cytometry.The expression of PGRN at mRNA and protein levels was detected by RT-qPCR and Western blot.The protein levels of caspase-3, Bcl-2, Bax, IL-1β, IL-6, TNF-α, p65 and p-IκB-α were determined by Western blot.RESULTS:Compared with control group, the cell proliferation rate was decreased (P<0.05), and the apoptotic rate was increased (P<0.05) in LPS group.The protein levels of caspase-3 and Bax were significantly up-regulated (P<0.05), and the expression of Bcl-2 was down-regulated (P<0.05).The protein levels of IL-1β, IL-6 and TNF-α were significantly up-regulated (P<0.05), and the protein levels of p65 and p-IκB-α were enhanced (P<0.05).Compared with LPS group, the cell proliferation rate was increased (P<0.05), and the apoptotic rate was decreased (P<0.05) in PGRN+LPS group.The protein levels of caspase-3 and Bax were significantly down-regulated (P<0.05), and the expression of Bcl-2 was up-regulated (P<0.05).The protein levels of IL-1β, IL-6 and TNF-α were significantly down-regulated (P<0.05), and the protein levels of p65 and p-IκB-α were decreased (P<0.05).CONCLUSION:PGRN over-expression may alleviate LPS-induced abnormal proliferation, apoptosis and inflammatory cytokine production in the A549 cells and HPAEpiC cells, which may be associated with the regulation of NF-κB signaling pathway.