Erythropoietin inhibits SGK1-dependent Th17 cell induction and Th17 cell–dependent kidney disease
Chiara Donadei, … , Peter S. Heeger, Paolo Cravedi
Chiara Donadei, … , Peter S. Heeger, Paolo Cravedi
Published April 23, 2019
Citation Information: JCI Insight. 2019;4(10):e127428. https://doi.org/10.1172/jci.insight.127428.
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Research Article Immunology Nephrology

Erythropoietin inhibits SGK1-dependent Th17 cell induction and Th17 cell–dependent kidney disease

Abstract

IL-17–producing CD4+ (Th17) cells are pathogenically linked to autoimmunity and, specifically, to autoimmune kidney disease. The newly recognized immunoregulatory functions of erythropoietin (EPO) and its predominant intrarenal source suggested that EPO physiologically regulates Th17 cell differentiation, thereby serving as a barrier to development of autoimmune kidney disease. Using in vitro studies of human and murine cells and in vivo models, we show that EPO ligation of its receptor (EPO-R) on CD4+ T cells directly inhibits Th17 cell generation and promotes transdifferentiation of Th17 cells into IL-17–FOXP3+CD4+ T cells. Mechanistically, EPO/EPO-R ligation abrogates upregulation of SGK1 gene expression and blocks p38 activity to prevent SGK1 phosphorylation, thereby inhibiting RORC-mediated transcription of IL17 and IL23 receptor genes. In a murine model of Th17 cell–dependent aristolochic acid–induced interstitial kidney disease associated with reduced renal EPO production, we demonstrate that transgenic EPO overexpression or recombinant EPO (rEPO) administration limits Th17 cell formation and clinical/histological disease expression. EPO/EPO-R ligations on CD4+ T cells abrogate, while absence of T cell–expressed EPO-R augments, Th17 cell induction and clinical/histological expression of pristane-induced glomerulonephritis (associated with decreased intrarenal EPO). rEPO prevents spontaneous glomerulonephritis and Th17 cell generation in MRL-lpr mice. Together, our findings indicate that EPO physiologically and therapeutically modulates Th17 cells to limit expression of Th17 cell–associated autoimmune kidney disease.

Authors

Chiara Donadei, Andrea Angeletti, Chiara Cantarelli, Vivette D. D’Agati, Gaetano La Manna, Enrico Fiaccadori, Julian K. Horwitz, Huabao Xiong, Chiara Guglielmo, Susan Hartzell, Joren C. Madsen, Umberto Maggiore, Peter S. Heeger, Paolo Cravedi

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Figure 2

EPO counteracts NaCl-induced p38 activation.

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EPO counteracts NaCl-induced p38 activation. (A) SGK1 gene expression in...
(A) SGK1 gene expression in enriched human CD4+ T cells activated with anti-CD3/anti-CD28–coated beads plus EPO (1000 IU/ml) or vehicle control in media or with an additional 20–40 mM NaCl or 40–80 mM urea added for 24 hours (qRT-PCR). (B) Representative plot and (C) data quantification of pSGK1 expression in enriched human CD4+ T cells activated with anti-CD3/anti-CD28–coated beads plus EPO (1000 IU/ml) or vehicle control for 10–30 minutes in 40 mM of urea media or 20 mM of NaCl with or without EPO assayed by flow cytometry (n = 5 donors). The results are expressed as medians of the percentage of pSGK1 versus unstimulated cells. (D–F) Enriched human naive CD4+ T cells were cultured in Th17 cell–polarizing conditions with or without EPO (1000 IU/ml) and SGK1 inhibitor GSK650394 (10 nM) (n = 3–4 donors). (D) RORC and IL17 mRNA at 24 hours. (E) IL-17 and (F) IL-23R expression after 5 days of culture (representative plots in Supplemental Figure 5). (G) Representative plot and (H) data quantification of pp38 expression in enriched human CD4+ T cells activated, as in B and C. (I) RORC gene expression in enriched human naive CD4+ T cells cultured for 24 hours under Th17 cell–polarizing conditions in standard media or with an additional 20 mM NaCl added with or without EPO and p38 activator anisomycin (10 μg/ml) (n = 7 donors). (J and L) Representative plots and (K and M) data quantification of IL-17 and IL-23R expression in enriched human naive CD4+ T cells cultured under Th17 cell–polarizing conditions for 5 days with or without EPO and p38 activator anisomycin (10 μg/ml) (n = 5 donors). *P < 0.05 vs. NaCl + EPO, #P < 0.05 vs. 0 min (no NaCl or urea), paired t test or 2-way ANOVA with Tukey test. Data represent mean ± SEM.