[Transcriptome changes upon Toll-like receptor 9 pathway activation in primary renal tubular epithelial cells]

To explore the effect of Toll-like receptor 9 (TLR9) signaling pathway activation on the transcriptome in the renal tubular cells.

Mouse primary renal tubular epithelial cells were extracted and cultured. When the degree of cell fusion reached 80%, they were divided into two groups, which were added with 10 μL phosphate buffered saline (PBS, PBS control group) and TLR9 activator cytosine phosphate guanidine oligodeoxynucleotide (CpG-ODN) with a final concentration of 5 μmol/L (CpG-ODN treatment group). The RNA sequencing was performed on the Illumina platform after extraction. DEGseq software was used to analyze the differential expression of genes between the two groups. Goatools and KOBAS online software were used to analyze the differential genes involved signal pathways. Homer software was used to predict transcription factors.

Compared with the PBS control group, there were a total of 584 differentially expressed genes in the CpG-ODN treatment group, of which 102 were up-regulated and 482 were down-regulated. The most significantly enriched gene ontology (GO) terms of differentially expressed genes included response to interferon-β, defense response to virus and other inflammatory pathway. The most significantly enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways included 2^'-5^'-oligoadenylate synthase activity, regulation of ribonuclease activity, negative regulation of virus life cycle, cellular response to interferon-βand defense response to protozoan. The results of transcription factor prediction showed that interferon regulatory factor 3 (IRF3) was the most significantly enriched transcription factor in the promoter sequence of differential genes; the most significant transcription factor downstream of TLR9 was IRF3, and other predicted transcription factors such as transcription factor 21 (TCF21), zinc finger protein 135 (ZNF135), and PR domain containing 4 (PRDM4) might be new candidates for TLR9 signaling pathway.

CpG-ODN activates TLR9 signaling pathway, and primary renal tubular epithelial cells can directly respond to CpG-ODN stimulation and undergo transcriptome changes, which provides a basis for further research on the molecular mechanism of TLR9 pathway in sepsis induced acute kidney injury.