Fig. 3.

Circulating IgA1-containing immune complexes (cIgA1) from IgA nephropathy (IgAN) patients induced upregulated MMP9 expression in mesangial cells. a The mRNA expression of MMP9 in human mesangial cells was significantly upregulated by cIgA1 derived from IgAN patients (1.01 [0.76, 1.99] vs. 0.57 [0.41, 0.97], p = 0.003). b Moreover, the expression of MMP9 and TREM-1 showed positive correlation in mesangial cells after cIgA1 treatment (r = 0.551, p < 0.001). However, the expression of MMP2 was comparable between the IgAN-cIgA1 group and the healthy control (HC)-cIgA1 group (c; 0.97 [0.84, 1.19] vs. 0.94 [0.75, 1.02], p = 0.242).