Premium
Interleukin‐6 Receptor Alpha Exhibits Differential Cellular Localization Within the Nephron
Author(s) -
Kronk Trinity Augusta,
Theilig Franziska,
AlKhalili Otor,
Mallick Rickta,
Eaton Douglas C,
Hoover Robert S,
Wynne Brandi Michele
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.966.6
Subject(s) - nephron , cytokine , biology , kidney , distal convoluted tubule , endocrinology , medicine , microbiology and biotechnology , receptor , renal sodium reabsorption , signal transduction , chemistry , reabsorption , immunology , biochemistry
Interleukin‐6 (IL‐6) is a pleiotropic cytokine produced by a variety of cells and is a key component of the body's inflammatory response. In addition, IL‐6 has been implicated in mediating the systemic inflammation observed during hypertension. However, little evidence demonstrates the mechanisms by which IL‐6 may be signaling within the kidney, thus regulating sodium balance. IL‐6 is known to signal via the transmembrane IL‐6 receptor alpha (IL‐6Rα); however, literature suggests that membrane bound IL‐6Rα is present only on select immune cells and hepatocytes, leaving most signaling events to occur via the soluble IL‐6Rα. We sought to determine the expression and localization of IL‐6 receptor alpha (IL‐6Rα) within the kidney. In particular, these data focus on IL‐6Rα expression in the aldosterone‐sensitive distal nephron (ASDN), where fine‐tuning of sodium reabsorption occurs via aldosterone (Aldo). Thus, we hypothesized that IL‐6Rα levels are increased via Aldo. For immunofluorescence (IF) studies, we used a model of mouse distal convoluted tubule cells (mDCT15 cells) and observed a cytosolic staining pattern within the mDCT15 cells. IF studies in murine kidney slices (IL‐6Rα and NCC) also revealed a cytosolic pattern within the DCT, while apical staining was observed in other nephron segments ( Figure 1) demonstrating a differential localization of IL‐6Rα within the kidney. Real‐time PCR (PCR) and western blot (WB) studies were performed using whole cell lysates from mDCT15 cells. Using PCR, we confirmed mRNA for IL‐6Rα is present and WB data demonstrate that the larger IL‐6Rα protein (85kDa) is expressed. Cells treated with Aldo (100nM, 24hr) exhibited an increased expression of both mRNA (1.6 ± 0.1 fold change/vehicle, p<0.01, n=4) and protein (3.3±0.04 fold change/vehicle, n=2) expression. These data demonstrate that IL‐6Rα is present within the kidney cortex and distributed within the cytosol and near the apical membrane. In addition, we demonstrate that IL‐6Rα is increased with Aldo treatment, suggesting that IL‐6/ IL‐6Rα signaling may be important in conditions where increased Aldo levels are present. Support or Funding Information NIDDK085097‐RSH2T32DK7656‐21 Emory Renal Division‐BMW 1Immunofluorescence of IL‐6Rα (A, red), NCC (B, green) and merged (C) in murine kidney cortex.