Calcium channel Orai1 promotes lymphocyte IL-17 expression and progressive kidney injury
Purvi Mehrotra, … , Javier A. Neyra, David P. Basile
Purvi Mehrotra, … , Javier A. Neyra, David P. Basile
Published August 15, 2019
Citation Information: J Clin Invest. 2019;129(11):4951-4961. https://doi.org/10.1172/JCI126108.
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Research Article Inflammation Nephrology

Calcium channel Orai1 promotes lymphocyte IL-17 expression and progressive kidney injury

Abstract

We hypothesized that the store-operated calcium entry (SOCE) channel, Orai1, participates in the activation of Th17 cells and influences renal injury. In rats, following renal ischemia/reperfusion (I/R), there was a rapid and sustained influx of Orai1+ CD4 T cells and IL-17 expression was restricted to Orai1+ cells. When kidney CD4+ cells of post–acute kidney injury (post-AKI) rats were stimulated with angiotensin II and elevated Na+ (10–7 M/170 mM) in vitro, there was an enhanced response in intracellular Ca2+ and IL-17 expression, which was blocked by SOCE inhibitors 2APB, YM58483/BTP2, or AnCoA4. In vivo, YM58483/BTP2 (1 mg/kg) attenuated IL-17+ cell activation, inflammation, and severity of AKI following either I/R or intramuscular glycerol injection. Rats treated with high-salt diet (5–9 weeks after I/R) manifested progressive disease indicated by enhanced inflammation, fibrosis, and impaired renal function. These responses were significantly attenuated by YM58483/BTP2. In peripheral blood of critically ill patients, Orai1+ cells were significantly elevated by approximately 10-fold and Th17 cells were elevated by approximately 4-fold in AKI versus non-AKI patients. Further, in vitro stimulation of CD4+ cells from AKI patients increased IL-17, which was blocked by SOCE inhibitors. These data suggest that Orai1 SOCE is a potential therapeutic target in AKI and CKD progression.

Authors

Purvi Mehrotra, Michael Sturek, Javier A. Neyra, David P. Basile

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Figure 5

Elevated Th17 and Orai1 expression and effect of SOCE on IL-17 responses in CD4+ blood lymphocytes in critically ill patients with or without AKI.

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Elevated Th17 and Orai1 expression and effect of SOCE on IL-17 responses...
(A) Representative FACS analysis of total peripheral blood cells in non-AKI (left, n = 8) vs AKI patients (right, n = 9) demonstrating the increase in CD4+ IL-17+–expressing cells. Quantification of the percentages of total IL-17+ cells (B) and CD4+/IL-17+ cells (C) in AKI versus non-AKI patients are shown. Representative dot plots showing (D) an increase in Orai-1+ cells in AKI patients as compared with non-AKI patients and (E) the percentage of Orai-1+ cells in AKI vs non-AKI patients. (F) Percentage of CD4+/IL-17+ cells gated on Orai1+ and Orai1– fractions (arrows). (G) IL-17 response to stimulation with elevated sodium (170 mM) and Ang II is shown for CD4+ cells isolated from AKI (n = 5) or non-AKI (n = 5) patients. Data are expressed as mean ± SE. *P < 0.05 by Student’s t test in AKI versus non-AKI patients (B–D), in Orai1+ versus Orai1– cells (F), or versus unstimulated (i.e., 140 mM and no Ang II) (G). †P < 0.05 inhibitors versus stimulated using 1-way ANOVA and Tukey’s post hoc test.