GLI3 is Inhibited by miR-143-3p and Attenuates Septic-induced Lung Injury and Inflammation by Targeting SFRP1.

Objectives: Transcription factors (TF) are the central regulatory hubs of signaling pathways in eukaryotic cells. Here, we explored the abnormal expression of TF in septic-induced lung injury by sequencing.

Methods: The levels of target proteins were detected using Western Blot and Elisa. Cell function was evaluated using CCK8 and transwell assays. A double luciferase reporter assay was performed to detect interactions between target molecules.

Results: We found that TF glioma-associated oncogene (GLI) family zinc finger 3 (GLI3) was abnormally low expressed in a lipopolysaccharide (LPS) induced acute lung injury (ALI) cell model. In an in vitro model, GLI3 overexpression promoted the proliferation and migration and inhibited apoptosis of lung epithelial cells in LPS-induced inflammatory environment. Importantly, GLI3 overexpression inhibited the secretion of inflammatory factors IL-1β, IL-6, and TNF-α. Additionally, miR-143-3p inhibited the expression of GLI3. MiR-143-3p inhibitor alleviated the cell damage caused by LPS, while knocking down GLI3 counteracted this effect, indicating that miR-143-3p downregulated GLI3 and inhibited its anti-inflammatory effect. Secreted frizzled related protein-1 (SFRP1) was upregulated in LPS-treated cells and SFRP1 promoter interacted with GLI3, suggesting that SFRP1 was a target of TF GLI3. Co-transfection with GLI3 knockdown and SFRP1 overexpression plasmids attenuated the secretion of inflammatory factors IL- 1β, IL-6, and TNF-α caused by GLI3 knockdown in LPS-treated cells, indicating that SFRP1 plays an anti-inflammatory role as a GLI3 target in the ALI cell model.

Conclusions: miR-143-3p caused degradation of GLI3 mRNA and thus inhibited the transcription of SFRP1, leading to decreased proliferation and increased levels of inflammatory factors, providing new potential targets for the clinical diagnosis and treatment of ALI.