Figure 1
TRPM7 expression is up-regulated in renal damage. The left kidney was obstructed in C57BL/6 mice by ureter ligation (UUO mouse model, see Methods) inducing progressive kidney damage17,28 (n = 5). After 7 days, obstructed (UUO kidneys) and non-obstructed contralateral kidneys (CLK kidneys) were collected from sacrificed mice. (a) The level of TRPM7 mRNA expression was assessed in tissue from cortical kidney using qRT-PCR. (*p < 0.001). (b) The level of TRPM7 protein expression was examined in cortical kidney tissue using western blotting. The full-length gel is presented in Suppl. Fig. S1c. (c) Upper panel: Representative picture of immunostaining against TRPM7 (magnification x200) in CLK kidneys, where white triangular arrows indicate low expression- and black triangular arrows high expression levels of TRPM7 in renal tubular epithelial cells. White arrows point to TRPM7-negative (TRPM7 staining not detectable) and black arrows point to TRPM7-positive renal interstitial cells. Lower panel: Representative picture of TRPM7 immunostaining in UUO kidneys, where TRPM7-high expression epithelial cells preferentially are localized in dilated renal tubules (black triangular arrow) and TRPM7-negative epithelial cells are localized in non-dilated tubules (blue triangular arrow) at day 7 after surgery. Scale bars represent 100 μm. (d) The percentage of TRPM7-high expression (black bar), TRPM7-low expression (gray bar) and non-detectable TRPM7 staining (white bar) in tubular epithelial cells assessed in a total of 10 non-overlapping fields. The average tubular epithelial cell number per field was 513 cells in CLK kidneys and 589 cells in UUO kidneys. *p < 0.001 vs. CLK kidneys. (e) The percentage of TRPM7-positive (black bar) or TRPM7-negative (non-detectable, white bar) interstitial cells assessed at same fields in (d). The average interstitial cell number per field was 121 cells in CLK kidneys and 444 cells in UUO kidneys. *p < 0.001 vs. CLK kidneys.
