Background: Several complex cellular and gene regulatory processes are involved in peripheral nerve repair. This study uses bioinformatics to analyze the differentially expressed genes (DEGs) in the satellite glial cells of mice following sciatic nerve injury. Methods: R software screens differentially expressed genes, and the WebGestalt functional enrichment analysis tool conducts Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomics (KEGG) pathway analysis. The Search Tool for the Retrieval of Interacting Genes/Proteins constructs protein interaction networks, and the cytoHubba plug-in in the Cytoscape software predicts core genes. Subsequently, the sciatic nerve injury model of mice was established and the dorsal root ganglion satellite glial cells were isolated and cultured. Satellite glial cells-related markers were verified by immunofluorescence staining. Real-time polymerase chain reaction assay and Western blotting assay were used to detect the mRNA and protein expression of Sox9 in satellite glial cells. Results: A total of 991 DEGs were screened, of which 383 were upregulated, and 508 were downregulated. The GO analysis revealed the processes of biosynthesis, negative regulation of cell development, PDZ domain binding, and other biological processes were enriched in DEGs. According to the KEGG pathway analysis, DEGs are primarily involved in steroid biosynthesis, hedgehog signaling pathway, terpenoid backbone biosynthesis, American lateral skeleton, and melanoma pathways. According to various cytoHubba algorithms, the common core genes in the protein–protein interaction network are Atf3, Mmp2, and Sox9. Among these, Sox9 was reported to be involved in the central nervous system and the generation and development of astrocytes and could mediate the transformation between neurogenic and glial cells. The experimental results showed that satellite glial cell marker GS were co-labeled with Sox9; stem cell characteristic markers Nestin and p75NTR were labeled satellite glial cells. The mRNA and protein expression of Sox9 in satellite glial cells were increased after sciatic nerve injury. Conclusions: In this study, bioinformatics was used to analyze the DEGs of satellite glial cells after sciatic nerve injury, and transcription factors related to satellite glial cells were screened, among which Sox9 may be associated with the fate of satellite glial cells.

Satellite glial cells (SGCs) within the dorsal root ganglion (DRG) possess the potential for transdifferentiation. Our previous study (doi: 10.1007/s12257-019-0317-x) has identified lncRNA ENSRNOT00000087717 (lnc87717) and its target AKT1 as potential regulators in the differentiation process of DRG-SGCs. In this study, the cell morphology of SGCs was assessed using immunofluorescence cytochemistry during the differentiation following knockdown of lnc87717, as well as downregulation or upregulation AKT1. The subcellular localization of lnc87717 was visualized by fluorescence in situ hybridization (FISH). The mRNA expression levels of lnc87717, AKT1, BDNF, TrkB, proBDNF, and p75NTR were assessed using qRT-PCR. For the in vivo study, 27 male Sprague-Dawley rats aged 6-9 weeks were used to establish the sciatic nerve injury model. The number of apoptotic cells in DRGs was subsequently detected in the AKT1 inhibitor, activator, and control group after the administration of proBDNF antiserum. In vitro, following knockdown of lnc87717, there was a significant decrease in the expression levels of proBDNF, BDNF, TrkB, and p75NTR (P<0.05). Furthermore, the number of nestin-positive SGCs and the expression of lnc87717 and AKT1 were increased in the AKT1-activated group (P<0.05). In vivo, compared to the control group, the number of apoptotic cells in the DRG was increased in the AKT1-inhibited group. Additionally, the expressions of lnc87717 and AKT1 were significantly upregulated (P<0.05), whereas the expression levels of PI3K, NF-κB, and Bad were significantly downregulated (P<0.05) in DRGs following AKT1 up-regulation compared to those in the control group. The differentiation of DRG-SGCs is suggested to be mediated through the activation of AKT1, while lnc87717 downregulates AKT1.