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. 2017 Oct 9;29(1):155–167. doi: 10.1681/ASN.2015060707

Figure 2.

Figure 2.

MYH9 E1841K mutation causes severe proteinuria and podocyte foot effacement in Ang II induced hypertension. (A) Mean SBP at baseline (averaged daily for 2 weeks) and after Ang II infusions (averaged for 4 weeks) are shown for each mouse. Mean of means of SBP for the same genotyped group of mice (n=6) at baseline: MYH9 +/+ 135.8±4.4, MYH9 +/E1841K 133.0±3.1, MYH9E1841K/E1841K 128.5±4.5; P=NS among groups, by ANOVA. After Ang II infusion: MYH9 +/+ 194.3±4.3, MYH9 +/E1841K 195.8±4.0, MYH9E1841K/E1841K 197.2±5.0; P=NS among groups, by ANOVA. For comparison of SBP on Ang II alone versus baseline within group, paired t test was used: P<0.001 for all three genotypes (***). Insert shows change in mean SBP from baseline and after Ang II infusion. (B) Treatment with Candesartan while on Ang II infusion significantly improved SBP. n=4 for each separate group of mice. Mean of means of SBP (mm Hg) for Ang II + Candesartan treatment are: MYH9 +/+ 146.5±5.0, MYH9 +/E1841K 136.0±5.7, and MYH9 E1841K/E1841K 142.5±1.0; P<0.001 (***) for Ang II alone versus Ang II + Candesartan by two-sample t test. (C) Urinary A/C ratio (µg/mg) for each individual mouse is shown on log scale (24-hour urine collected at the end of treatment period). Mean urinary A/C ratio for Ang II infusion alone (n=6 each): MYH9 +/+ 741.2±101.6, MYH9 +/E1841K 1328.8±292.5, MYH9E1841K/E1841K 2247.5±300.9; Ang II + Candesartan (n=4): MYH9 +/+ 57.0±24.5, MYH9 +/E1841K 54.9±14.3, and MYH9 E1841K/E1841K 65.2±24.1; ***P<0.001 (ANOVA) for Ang II alone versus Ang II + Candesartan for each group. (D) Mean urinary N/C ratio (µg/mg) for Ang II alone: MYH9 +/+ 7.94±2.61, MYH9 +/E1841K 9.29±2.89, MYH9E1841K/E1841K 33.40±7.63; **P=0.004 (ANOVA); Ang II + Candesartan: MYH9 +/+ 11.30±2.66, MYH9 +/E1841K 10.48±1.22, and MYH9 E1841K/E1841K 19.89±2.80; *P=0.04 (ANOVA). In MYH9E1841K/E1841K, P=NS for Ang II alone versus Ang II + candesartan (by two-sample t test). (E) Representative periodic acid–Shiff staining of kidney sections (40×). After Ang II alone: MYH9 +/+ and MYH9 +/E1841K had only very mild changes from baseline such as rare casts, whereas MYH9 E1841K/E1841K had FSGS and severe protein-filled microcysts. Treatment with Ang II + Candesartan: MYH9 +/+ and MYH9 +/E1841K showed no detectable changes from baseline, but MYH9 E1841K/E1841K showed absence of FSGS and protein-filled microcysts. Black scale bar=50 µm. (F) Total kidney pathology score for each individual mouse is shown. Mean total kidney pathology scores for Ang II alone: MYH9 +/+ 8.8±1.1, MYH9 +/E1841K 8.5±1.6, MYH9E1841K/E1841K 19.7±3.9; ***P=0.001 (ANOVA); Ang II + Candesartan: MYH9 +/+ 7.8±0.8, MYH9 +/E1841K 7.3±1.0, MYH9E1841K/E1841K 6.8±1.7; P=NS. For Ang II + Candesartan versus Ang II alone for MYH9E1841K/E1841K mice: *P=0.01 (by two-sample t test). Table shows kidney pathology scores for glomerular, tubular, interstitial, and vascular injuries during Ang II infusion alone, and with treatment with candesartan. Glomerular injury includes hypercellularity; focal, segmental, and mesangial expansion; FSGS; and thickened membrane; tubular injury consists of fibrosis and tubular casts. Interstitial injuries represent chronic inflammation (focal and diffuse). Vascular injury represents injury to arteries and arterioles. (G) Representative transmission EM images for Ang II and Ang II + Candesartan. After Ang II alone: MYH9 +/+ and MYH9 +/E1841K have mild podocyte FP effacement, MYH9 E1841K/E1841K have very severe and >80% podocyte FP effacement/fusion. Treatment with Ang II + Candesartan: MYH9 +/+ have normal FPs, MYH9 +/E1841K with rare FP effacement, and MYH9 E1841K/E1841K show amelioration of FP effacement from very severe after Ang II to mild-to-moderate when treated with candesartan. Black scale bar under the picture represents 2 µm. (H) Mean podocyte FP effacement scores after Ang II infusion: MYH9 +/+ 2.00±0.58, MYH9 +/E1841K 2.00±0.58, and MYH9E1841K/E1841K 5.0±0.0; **P<0.01 by ANOVA. After Ang II + Candesartan: MYH9 +/+ 1.0±0.0, MYH9 +/E1841K 2.00±0.58, and MYH9E1841K/E1841K 2.67±0.67; P=NS (ANOVA). In MYH9E1841K/E1841K mice, candesartan significantly decreased Ang II–induced podocyte injury (5.0±0.0 versus 2.67±0.67; *P=0.03 [one-way ANOVA]). Ang II + C, Ang II + Candesartan.