Figure 4.
Periostin and integrin-β3 are colocalized at the sites of injury in the model of NTS-induced GN. (A and D) Immunohistochemical staining for periostin in WT/KO (A) and scrambled/antisense (D) mice showing increased expression of periostin in glomeruli and vessels of WT NTS mice that is absent in KO and ameliorated in antisense mice. (B and E) Integrin-β3 mRNA expression is induced in WT NTS (B) and NTS scrambled (E) mice but is highly ameliorated in KO NTS and NTS antisense mice, respectively. (C and F) Immunohistochemical localization of integrin-β3 in WT/KO (C) and scrambled/antisense (F) mice showing increased expression in glomeruli and vessels of WT NTS mice that is highly attenuated in KO and antisense mice, respectively. (G) Immunohistochemical staining of integrin-β3 and periostin in serial sections of WT NTS mice, showing localization of both proteins at the same sites (arrows indicating expression of both proteins in the same structures). (H) Double immunofluorescence for periostin (green)/nestin (red) and integrin-β3 (green)/nestin (red) in WT NTS mice, showing that both periostin and integrin-β3 are expressed by podocytes in glomeruli of NTS mice. (I) Double immunofluorescence for periostin or integrin-β3 (green) with CD44 (red) in WT NTS mice showed that both proteins are strongly expressed by activated parietal epithelial cells. Double immunofluorescence for periostin (green) with α-SMA or CD146 (red) showed no colocalization with mesangial and endothelial cells, respectively. (J) Coimmunoprecipitation analysis using anti–integrin-β3 antibody successfully precipitated both integrin-β3 and periostin, showing that the two proteins interact in vivo in the NTS model. The samples were run on the same gel but were discontinuous. Animals were euthanized after 14 or 9 days of NTS in the series of experiments with the KO (A–C) or the antisense (D–J), respectively. Scale bars, 100 μm (G) or 50 μm (A, C, D, F, H, and I). Representative images are shown. n=5–7 per group. *P<0.05 versus WT PBS; #P<0.05 versus WT NTS or NTS scrambled.