Vasorin contributes to lung injury via FABP4-mediated inflammation

Background Lung injury caused by pulmonary inflammation is one of the main manifestations of respiratory diseases. Vasorin (VASN) is a cell-surface glycoprotein encoded by the VASN gene and is expressed in the lungs of developing mouse foetuses. Previous research has revealed that VASN is associated with many diseases. However, its exact function in the lungs and the underlying mechanism remain poorly understood. Methods and results To investigate the molecular mechanisms involved in lung disease caused by VASN deficiency, a VASN gene knockout (VASN −/− ) model was established. The pathological changes in the lungs of VASN −/− mice were similar to those in a lung injury experimental mouse model. We further analysed the transcriptomes of the lungs of VASN −/− mice and wild-type mice. Genes in twenty-four signalling pathways were enriched in the lungs of VASN −/− mice, among which PPAR signalling pathway genes (3 genes, FABP4, Plin1, AdipoQ, were upregulated, while apoA5 was downregulated) were found to be closely related to lung injury. The most significantly changed lung injury-related gene, FABP4, was selected for further verification. The mRNA and protein levels of FABP4 were significantly increased in the lungs of VASN −/− mice, as were the mRNA and protein levels of the inflammatory factors IL-6, TNF-α and IL-1β. Conclusions We believe that these data provide molecular evidence for the regulatory role of VASN in inflammation in the context of lung injury.