Insulin-like growth factor 2 (IGF2)
mRNA-
binding protein 2 (IGF2BP2) is a secreted
protein that can bind to IGF2 and has been reported to promote
inflammation. The data from the ENCORI database have predicted that IGF2BP2 can bind
caspase 4, which mediates pyroptosis and promotes airway
inflammation and
lipopolysaccharide (LPS)-induced
lung injury. The present study investigated whether IGF2BP2 can regulate LPS-induced lung cell
inflammation by targeting
caspase 4. Therefore, the non-tumorigenic lung epithelial cell line Beas-2B was transfected with
short hairpin RNA (shRNA)-IGF2BP2 and stimulated with LPS. A number of parameters, including cell viability, production of
interleukin (IL)-1β and
IL-18, activation of gasdermin D (GSDMD) and the expression levels of IGF2BP2,
caspase 4 and cleaved-
caspase 1, were subsequently assessed using
CCK-8, ELISA kits, western blotting and immunofluorescence staining, respectively.
RNA pull-down assay was used to probe the possible interaction between IGF2BP2 and
caspase 4
RNA. LPS treatment was found to inhibit cell viability, trigger IL-1β and
IL-18 production and increase IGF2BP2 expression in a concentration-dependent manner. Compared with cells transfected with
shRNA-negative control, cells that were transfected with shRNA-IGF2BP2 exhibited enhanced cell viability, reduced IL-1β and
IL-18 concentrations, decreased GSDMD activation in addition to reduced expression levels of
caspase 4 and cleaved-
caspase 1 following stimulation with 1 µg/ml LPS. Concomitantly, the effects of IGF2BP2 silencing on
caspase 4 expression were higher compared with those noted on
caspase 1. In addition, binding of IGF2BP2 to
caspase 4
RNA was also observed. To conclude, data from the present study suggest that IGF2BP2 knockdown inhibited LPS-induced Beas-2B cell
inflammation by targeting
caspase 4, thereby inhibiting the non-canonical pyroptosis pathway.