KCl and KHCO₃ regulate pendrin expression.

<p>Pendrin mRNA and protein abundance in kidney cortex from mice treated with KCl or KHCO₃ for 7 days were examined by real-time RT-PCR (<b>A</b>) and immunoblotting (<b>B</b>). All membranes were stripped and reprobed for β-actin. (<b>C</b>) Bar graphs summarizing data from immunoblotting. All data were normalized against β-actin. Data are given as normalized mean ± SE; <i>n</i> = 5–7 animals/group. *<i>p</i>≤0.05, **<i>p</i>≤0.01, ***<i>p</i>≤0.001.</p

Immunolocalization of intercalated cell subtypes in mouse kidney under different dietary treatments.

<p>Mice were left untreated (sucrose, control) or received NH₄Cl, NaHCO₃ or KCl in their drinking water for 7 days. Immunohistochemistry was performed to identify type A intercalated cells with AE1 (red), non-type A intercalated cells with pendrin (green), principal cells with calbindin D28k/AQP2 (yellow), and nuclei (DAPI, blue). Representative pictures are shown from CNT (<b>A</b>) and CCD (<b>B</b>). Original magnification 400×.</p

AE1 expression is not regulated in kidney cortex.

<p>The mRNA and protein abundance of the type A intercalated cell specific Cl⁻/HCO₃⁻ exchanger AE1 was measured by real-time RT-PCR (<b>A</b>) and immunoblotting (<b>B</b>) in kidney cortex. (<b>C</b>) Bar graphs summarizing data from immunoblotting. All data were normalized against β-actin obtained on the same immunoblotting membrane after stripping. Data are given as normalized mean ± SE; <i>n</i> = 5–7 animals/group.</p

Medullay AE1 is not regulated by KCl and KHCO₃.

<p>AE1 mRNA and protein abundance in kidney medulla from mice treated with KCl or KHCO₃ for 7 days were measured by real-time RT-PCR (<b>A</b>) and immunoblotting(<b>B</b>). All membranes were stripped and reprobed for β-actin. (<b>C</b>) Bar graphs summarizing data from immunoblotting. All data were normalized against β-actin. Data are given as normalized mean ± SE; <i>n</i> = 5–7 animals/group.</p

Remodeling of the collecting duct.

<p>Kidneys from mice left untreated (sucrose, control) or receiving KCl, NaHCO₃ or NH₄Cl for 7 days were sectioned and stained for specific cell markers (AE1 for type A intercalated cells, pendrin for non-type A intercalated cells, and calbindin D28k and AQP2 for principal cells). The relative number of cells expressing these markers was counted for the different segments of the collecting system. CNT connecting tubule, CCD cortical collecting duct, OMCD outer medullary collecting duct, _iIMCD initial inner medullary collecting duct, *<i>p</i>≤0.05, ***<i>p</i>≤0.001.</p

Pendrin expression in kidney cortex regulated by various treatments.

<p>The mRNA and protein abundance of the type B intercalated cell specific Cl⁻/HCO₃⁻ exchanger pendrin was measured by real-time RT-PCR (<b>A</b>) and immunoblotting (<b>B</b>) in kidney cortex. (<b>C</b>) Bar graphs summarizing data from immunoblotting. All data were normalized against β-actin obtained on the same immunoblotting membrane after stripping. Data are given as normalized mean ± SE; <i>n</i> = 5–7 animals/group. *<i>p</i>≤0.05, **<i>p</i>≤0.01.</p

DOCA or NaHCO₃ alone do not alter AE1 expression in kidney cortex.

<p>The mRNA and protein abundance of AE1 in kidney cortex from mice treated with NaHCO₃ or DOCA alone was measured by real-time RT-PCR (<b>A, B</b>) and immunoblotting (<b>C</b>) in the kidney cortex. (<b>D</b>) Bar graphs summarizing data from immunoblotting. All data were normalized against β-actin obtained on the same immunoblotting membrane after stripping. Data are given as normalized mean ± SE; <i>n</i> = 5–7 animals/group.</p

Summary of urine data from mice receiving different treatments.

<p>All animals were treated for 7 days and placed into metabolic cages for the final 3 days. Urine analysis was performed from samples collected under mineral oil over the last 24 hrs. Values are means ± SE; <i>n</i> = 5–7/group. Shown is a summary of urinary data from all different treatment groups and the corresponding controls. BW, body weight, crea creatinine.</p>*<p><i>p</i><0.05,</p>**<p><i>p<</i>0.01,</p>***<p><i>p</i><0.001.</p

Suppression of Dicer leads to a glomerulocystic disease.

<p>Representative pictures of hematoxylin and eosin (A-F) and Masson’s Trichrome (G,I). Staining of Ctr (A, D, G), Dicer cKO kidneys at P30 (B, E, H) and Dicer cKO kidneys at P50 (C, F, I). Dicer induced cyst formation is limited to the cortex (C). Dicer cKO mice present a glomerulocystic phenotype and tubular dilatation at P50 (F). These alterations are not so prominent at P30, where only sites of dilatation in Bowman capsule can be sporadically seen (E). Interstitial fibrosis is evident in Dicer cKO mice at P50 (I). (A, B, C) Magnification 5X. (D- I) Magnification 40X.</p

Alterations of GSK3β / β-catenin are associated with the development of the glomerulocystic phenotype.

<p>Representative pictures of renal cortex from 30 (A, B) and 50 days old (C, D) mice. Ctr (A, C) and Dicer cKO (B, D) sections were stained with anti β-catenin antibody. In Dicer cKO, β-catenin expression is limited to the basolateral domain in both tubules and parietal cells of the Bowman’s capsule, at both P30 and P50 (B-D). (A-D) Magnification 63X, zoom1.5. Panel E and F show immunoblotting of Cortex/OSOM samples of 30 (E) and 50 (F) days old mice. GSK3β expression is already upregulated at the pre-cystic stage (P30) in Dicer cKO mice (E) and this is persistent at P50 (F). Glomerular cyst formation is associated with loss of cytosolic β-catenin expression and general downregulation of cortical protein level (F). No significant changes were observed in the fraction of their main regulating phosphorylated forms. Panel G represent qPCR analysis of mRNA of β-catenin in 30 (right) and 50 days old mice (left). mRNA level of β-catenin is downregulated in Dicer-cKO mice at P50. Data are expressed as mean ± sem; n power is 5 vs 5. * is for p value < 0.05; ** is for p-value <0.01.</p