Changjian Liu, Yongpeng Ge

Department of Rheumatology, the Key Laboratory of Myositis, China-Japan Friendship Hospital, Beijing, People’s Republic of China

Correspondence: Yongpeng Ge, Department of Rheumatology, The Key Laboratory of Myositis, China-Japan Friendship Hospital, Yinghua East Road, Chaoyang District, Beijing, 100029, People’s Republic of China, Email gyp2016@163.com

Background: Interstitial lung disease (ILD) is one of the significant complications of dermatomyositis (DM), but the mechanisms by which it occurs remain incompletely elucidated. This study aimed to explore further the possible genetic mechanisms by which this complication occurs.
Methods: Gene expression profiles for DM (GSE39454, GSE46239, GSE143323) and ILD (GSE32537, GSE110147, GSE150910) were downloaded from the Gene Expression Omnibus (GEO) database. After identifying common differentially expressed genes (DEGs) to DM and ILD using the “limma” R package and the “VennDiagram” R package, functional annotation, relationship to immune cell infiltration, identification of transcription factors (TFs), we also collected clinical cases of DM-associated ILD (DM-ILD), including 3 cases of rapidly progressive ILD (RP-ILD) and 3 cases of none-RP-ILD, and explored whether there were differences in serum lymphocyte subpopulations.
Results: A total of 4 common DEGs (SLAMF7, SPP1, TDO2, and VCAM1) were screened and Gene Ontology (GO) enrichment analysis showed that these genes were mainly enriched in T cell activation, regulation of lymphocyte activation, lymphocyte differentiation, leukocyte proliferation and regulation of T cell activation. In terms of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, the three significantly enriched pathways were the PI3K-Akt signaling pathway, MAPK signaling pathway, and Cytokine-cytokine receptor interaction. In lung and muscle tissues, 21 and 3 TFs may regulate the expression of these genes, respectively. Finally, by analysing the serum lymphocyte subpopulations, we also found a decrease in the absolute number of CD8+ T cells and an increase in the CD4+ /CD8+ T cell ratio in DM combined with RP-ILD.
Conclusion: These common pathways and key genes may provide new ideas for further research into DM-ILD.

Keywords: dermatomyositis, interstitial lung disease, differentially expressed genes, immune cells