Integration of apaQTL and eQTL analysis reveals novel SNPs associated with occupational pulmonary fibrosis risk

LGALS3 regulates endothelial-to-mesenchymal transition via PI3K/AKT signaling pathway in silica-induced pulmonary fibrosis

Silicosis is a progressive and chronic occupational lung disease characterized by lung inflammation, silicotic nodule formation, and diffuse pulmonary fibrosis. Emerging evidence indicates that endothelial-mesenchymal transition (EndoMT) plays a crucial role in the development of silicosis. Herein, we conducted a SiO2-induced EndoMT model and established a mouse model with pulmonary fibrosis by silica. We identified that SiO2 effectively increased the expression of mesenchymal markers while decreasing the levels of endothelial markers in endothelial cells. It's further demonstrated that SiO2 induced the PI3K/Akt signaling pathway activation via LGALS3 synthesis. Next, interfering LGALS3 blocked the process of EndoMT by inhibiting the activity of PI3K/AKT signaling. In vivo, the administration of a specific PI3K inhibitor LY294002 significantly alleviated silica-induced pulmonary fibrosis. Collectively, these results identified that the LGALS3/PI3K/AKT pathway provided a rationale target for the clinical treatment and intervention of silicosis.

Multi-omics and multi-stages integration identified a novel variant associated with silicosis risk

Assessing the association between candidate single-nucleotide polymorphisms (SNPs) identified by multi-omics approaches and susceptibility to silicosis. RNA-seq analysis was performed to screen the differentially expressed mRNAs in the fibrotic lung tissues of mice exposed to silica particles. Following this, we integrated the SNPs located in the above human homologenes with the silicosis-related genome-wide association study (GWAS) data to select the candidate SNPs. Then, expression quantitative trait locus (eQTL)-SNPs were identified by the GTEx database. Next, we validated the associations between the functional eQTL-SNPs and silicosis susceptibility by additional case-control study. And the contribution of the identified SNP and its host gene in the fibrosis process was further validated by functional experiments. A total of 12 eQTL-SNPs were identified in the screening stage. The results of the validation stage suggested that the variant T allele of rs419540 located in IL12RB1 significantly increased the risk of developing silicosis [additive model: odds ratio (OR) = 1.78, 95% confidence interval (CI) 1.11-2.85, P = 0.017]. Furthermore, the combination of GWAS and the results of validation stage also indicated that the variant T allele of rs419540 in IL12RB1 was associated with increased silicosis risk (additive model: OR = 2.07, 95% CI 1.38-3.12, P < 0.001). Additionally, after knockdown or overexpression of IL12RB1, the levels of pro-inflammatory factors, such as IL-12, IFN-γ, and other pro-inflammatory factors, were correspondingly decreased or increased. The novel eQTL-SNP, rs419540, might increase the risk of silicosis by modulating the expression levels of IL12RB1.