S100A8 and infection: To further determine whether H. pylori CagA was responsible for the increased expression of miR-223-3p, we used a isogenic 26695 CagA mutant strain (CagA−) to infect the cells and found that the isogenic 26695 CagA mutant strain infection had no effect on the expression of miR-223-3p (Fig. 1a, b).