Sulfur dioxide attenuates hypoxia-induced pulmonary arteriolar remodeling via Dkk1/Wnt signaling pathway.

Abstract Objective This study investigated the impact of SO 2 on rats with hypoxic pulmonary vascular structural remodeling and its possible mechanisms. Materials and methods Pulmonary vascular morphological change was examined by HE staining. RNA-based high-throughput sequencing (RNA-seq) was performed to detect differential expression of mRNAs in Normal and Hypoxia–induced Pulmonary hypertension (HPH) rats. The Real-time quantitative RT-PCR (q RT-PCR) was used for validation of wnt7b, sfrp2, cacna1f, DKK1, CaSR and vimentin mRNA expression levels. Protein levels of CaSR, Vimentin, Caspase3, E-cadherin and P-Akt1/2/3 were detected by Western blot and immunohistochemistry. Results This study showed that SO 2 significantly attenuated the interstitial thickening and prominent media hypertrophy of pulmonary arteries. SO 2 downregulated p-Akt1/2/3 protein level and upregulated E-cadherin protein level in lung tissues, which inhibited the proliferation and epithelial-to-mesenchymal transition (EMT) in HPH rats. RNA-seq and PCR validation results showed that levels of Wnt7b, Sfrp2 and Cacna1f mRNAs decreased and Dkk1 mRNA level increased obviously in HPH rats. Moreover, SO 2 attenuated the mRNA and protein level of CaSR, which was activated in HPH rats and resulted in the proliferation of PASMCs. Besides, the mRNA and protein expression of vimentin in PASMCs significantly reduced after SO 2 treatment. Conclusion Together, these findings indicate that SO 2 could attenuate hypoxia-induced pulmonary arteriolar remodeling and may suppress the proliferation and migration of PASMCs at least in part through the Dkk1/Wnt signaling pathway.