Wentao Chen,1,* Qian Zhang,2,* Zhiwei Zhang,1,* Yaping Ding,3 Feng Zhang,3 Guo Chen1 

1Department of Orthopedics, Chengdu Integrated TCM & Western Medicine Hospital / Chengdu First People’s Hospital, Chengdu, Sichuan, People’s Republic of China; 2Department of Environmental and Occupational Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China; 3Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Guo Chen, Email 1735155@qq.com

Background: Spinal cord injury (SCI) is a major disabling disease. However, the complex secondary injury mechanisms make the results of treatment unsatisfactory. This study aimed to screen for key biomarkers of SCI and explore immune cell infiltration to identify novel therapeutic targets for improving neurological recovery after the injury.
Methods: The SCI-associated gene microarray dataset was downloaded from GEO. The differential genes (DEGs) were first screened and analyzed according to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment for DEGs biological functions and pathways, while the protein-protein interaction (PPI) network was established using STRING. Then, the Hub genes of SCI were mined by WGCNA and LASSO regression analysis. Finally, the level of infiltration of 24 immune cells was analyzed using the CIBERSORT method.
Results: A total of 522 DEGs were filtered. Enrichment analysis of their biological functions and pathways yielded the most closely related results for inflammatory response, regulation of cytokine production, neutrophil chemotaxis and degranulation, angiogenesis, cell death, TNF signaling pathway, and osteoclast differentiation. Four co-expression modules were obtained using WGCNA. Four Hub genes (2010004M13Rik, Cdkn1c, Nox4, and Gpr101) were obtained by analysis using the LASSO algorithm and validated by qRT-PCR. Finally, the infiltration of M0 and M2 macrophages, T Cells CD4 Follicular, and DC activated was assessed by immune infiltration analysis and was found to be associated with SCI.
Conclusion: 2010004M13Rik, Cdkn1c, Nox4, and Gpr101 are Hub genes in SCI. Infiltration of M0, M2 macrophages, T Cells CD4 Follicular, and DC activated may also be associated with inflammation and neurological recovery after SCI.

Keywords: spinal cord injury, neurological recovery, inflammation, immune cell, weighted gene co-expression network analysis