Renal TH17 cells are Elevated in Humanized Sickle Cell Mice

Abstract

Sickle cell nephropathy (SCN) is a major complication of sickle cell disease (SCD). However, it is not fully understood what role immune cells play in SCN. Recent studies have implicated IL‐17A+CD4+(TH17) cells in mediating kidney disease outside of SCD. Furthermore, levels of circulating TH17 cells are elevated in SCD patients. We have previously reported that humanized sickle cell (HbSS) mice show progressive age‐dependent nephropathy with proteinuria, glomerulosclerosis, loss of GFR, and elevated CD3+cells compared to control (HbAA) mice. However, a role for renal TH17 cells in SCN has not yet been defined. We hypothesized that HbSS mice have elevated renal TH17 cells compared to HbAA mice. Thus, we phenotyped renal and splenic lymphocytes from 16–24 week‐old male HbAA and HbSS mice by flow cytometry. HbSS mice had increased renal TH17 cells compared to HbAA mice (18.3 ± 2.0% vs. 0.2 ± 0.1%, respectively; p<0.001) but no difference in renal CD4+cells. No differences were observed in splenic TH17 cells between HbSS and HbAA mice, which correlated with similar frequencies of splenic CD4+cells. Interestingly, HbSS mice had a significant increase in renal CXCR3+CD4+(TH1) cells compared to HbAA mice (48.8 ± 2.3% vs. 10.9 ± 3.3%, respectively; p<0.001) but no difference in splenic TH1 cells. Next, we measured changes in circulating proinflammatory mediators by Luminex multiplex technology. HbSS mice had elevated levels of soluble intercellular adhesion molecule 1 (sICAM‐1: 2937 ± 240 ng/mL vs. 2396 ± 57 ng/mL, respectively; p=0.04 ) and plasminogen activator inhibitor 1 (PAI‐1: 546.9 ± 120 ng/mL vs. 69.6 ± 4.5 ng/mL; p=0.001 ) compared to HbAA mice. We conducted a preliminary flow cytometric analysis of activated renal and splenic CD4+cells from aged (8–13 month‐old) mice and observed decreased splenic CD4+cells in aged HbSS mice compared to aged HbAA mice (5.1% vs. 32.5%, respectively; n = 2) but no differences in renal CD4+cells. Activated CD44hiCD4+cells from aged HbSS mice were increased in both the spleen (68.8% vs. 30.8%; n = 2) and the kidney (22.2% vs. 14.0%, respectively; n = 2) compared to aged HbAA mice. We propose that these findings and initial observations suggest an important role for renal T cells, especially TH17 and TH1 cells, in promoting and exacerbating kidney injury and dysfunction in SCD.Support or Funding InformationSupport provided by NIH T32 DK116672 to PAM, F30 DK107194 to BMF, NIH P01 HL136267 to CDM, JSP, DMP, NIH T32 AR069516 to RJM, NIH U01 HL117684 to JSP, DMP, and ASN Ben J. Lipps Research Fellowship to MK.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.