AUTHOR=Qu Ning , Chen Lei , Liang Shanshan , Wei Meng , Sun Lingshuang , He Quan , Xue Jinhong , Wang Meng , Shi Kehui , Jiang Hongli , Liu Hua 

TITLE=Roxadustat Attenuates the Disruption of Epithelial Tight Junction in Caco2 Cells and a Rat Model of CKD Through MicroRNA-223

JOURNAL=Frontiers in Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.850966

DOI=10.3389/fmed.2022.850966

ISSN=2296-858X

ABSTRACT=Introduction: Increasing evidence supports the idea that the disruption of epithelial tight junction proteins (TJPs) caused by accumulation of uremia toxins, such as homocysteine (Hcy), is one of the most important mechanisms underlying the damage of intestinal barrier function (IBF) in chronic kidney disease (CKD). Since the decrease of hypoxia inducible factor-1α (HIF-1α) is reported to be involved in Hcy-induced cell injury and the up-regulation of microRNA-223 (miR-223) plays a vital protective role on the impairment of IBF in the experimental colitis, we investiaged the effect of HIF-1α stabilizer roxadustat on the disruption of TJPs induced by Hcy and CKD and the underlying mechanism. Methods:  Chronic kidney disease was induced in rats via 5/6 nephrectomy. In a series of experiments, rats were treated orally with roxadustat  of different doses.The expression of tight junction proteins (TJPs) ,HIF-1α and  miR-223 was analyzed in different groups  by western blotting analysis and RT-PCR techniques. To discovery the mechanism, a series of experiments with cultured Caco2 cells was performed.Results: Our results showed that the expression of TJPs (occludin, claudin-1 and ZO-1) decreased significantly, accompanied by the reduction of HIF-1α and miR-223 in Hcy-treated Caco2 cells and colonic mucosa of uremic rats. Roxadustat reversed the reduction of HIF-1α and miR-223 and attenuated the decrease of TJPs expression induced by Hcy in Caco2 cells and in CKD rat colon tissue. Furthermore, transfection with miR-223 mimics increased the expression of TJPs while transfection with miR-223 inhibitor decreased their expression in Caco2 cells. miR-223 inhibitor applied before roxadustat treatment partly diminished the effect of roxadustat on TJPs expression in Caco2 cells. Conclusion: These results indicated that roxadustat attenuated the disruption of epithelial TJPs induced by Hcy in Caco2 cells and the damage of colonic epithelium in CKD rats through the up-regulation of miR-223 induced by HIF-1α. The present study provides a novel insight into the IBF dysfunction in CKD and suggests a potential therapeutic use of roxadustat for the IBF dysfunction besides anemia in CKD.