[Effect of aquaporin 5 on TLR4/MyD88/NF-κB signaling pathway in Sjögren syndrome rats].

OBJECTIVE

To investigate the effect of aquaporin 5 (AQP5) on Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor κB (NF-κB) signaling pathway in Sjögren syndrome (SS) rats.

METHODS

The SS gene expression data sets GSE406611 and GSE84844 were extracted from the Gene Expression Omnibus (GEO), and the AQP5 mRNA expression was analyzed by R software. The rat SS model was constructed. The successfully modeled rats were divided into SS group, SS+NC group, and SS+pc group, 10 rats in each group; and 10 rats were set as Normal group. The rats in the SS+NC group were injected with 10 μg of rno-pcDNA3.1-AQP5-NC at the submandibular gland, subcutaneously every day for 28 days. The rats in the SS+pc group were injected with 10 μg of rno-pcDNA3.1-AQP5 at the submandibular gland, subcutaneously every day for 28 days. The enzyme-linked immunosorbent assay (ELISA) kit was used to detect the content of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the serum. High-throughput sequencing was used to identify the target genes. Quantitative real-time PCR (qPCR) and Western blot were used to detect the mRNA and protein expressions of AQP5, TLR4, MyD88, and NF-κB in the rat submandibular gland tissue.

RESULTS

In the SS dataset GSE406611 and GSE84844, the mRNA expression of AQP5 in SS was significantly reduced. Compared with the Normal group, the content of TNF-α and IL-1β in the serum, the mRNA and protein expressions of TLR4, MyD88, and NF-κB in the SS group were significantly increased, the mRNA and protein expressions of AQP5 were significantly decreased. After overexpression of AQP5, the content of TNF-α and IL-1β in the serum, the mRNA and protein expressions of TLR4, MyD88, and NF-κB in the SS+pc group were significantly decreased, the mRNA and protein expressions of AQP5 were significantly increased. The differences were statistically significant (all P < 0.05).

CONCLUSION

The expression of AQP5 is involved in the progression of SS. Increasing the expression of AQP5 can significantly inhibit inflammatory stress and reduce the pathological damage of submandibular gland tissue. This may be related to the inhibition of TLR4/MyD88/NF-κB conduction.