Abstract: FR-PO703

Role of Monocyte Interleukin (IL)-27 in Minimal Change Nephrotic Syndrome (MCNS)

Session Information

Category: Glomerular

  • 1002 Glomerular: Basic/Experimental Pathology

Authors

  • Chan, Chang-Yien, National University of Singapore, Singapore, Singapore
  • Yeo, Wee Song, National University of Singapore, Singapore, Singapore
  • Chen, Jinmiao, Singapore Immunology Network (SIgN), (BMSI, A*STAR), Singapore, Singapore
  • Yang, Henry He, National University of Singapore, Singapore, Singapore
  • Yap, Hui Kim, National University of Singapore, Singapore, Singapore
Background

We have previously shown upregulation of lymphocyte IL-13 gene expression during nephrotic relapses in MCNS patients, associated with downregulation of pro-inflammatory cytokines, IL-8 and tumor necrosis factor (TNF)-α in lipopolysaccharide (LPS)-stimulated monocytes, and decreased monocyte CD14 expression, suggestive of an IL-13-induced anti-inflammatory effect. This study aimed to identify the monocyte ‘gene signature’ in MCNS patients and subsequently to validate the findings in human podocytes.

Methods

Monocyte RNA from 5 patients in relapse and remission were analysed using Illumina Human Ref8 chips. Subsequently plasma IL-27 levels were measured in 14 MCNS patients in relapse and remission and 20 healthy controls. The role of IL-27 in human podocytes was studied using cell migration assay (cultrex). Podocyte RhoA/Rac1 activity were measured using ELISA and STAT1/3 levels were studied using Western blot. Statistical analysis was done using Mann-Whitney test and Wilcoxon signed rank test for paired data.

Results

MetacoreTM analysis on the monocyte transcriptome of MCNS patients in relapse compared to remission revealed involvement of genes in IL-1 signaling, regulation of actin cytoskeleton by RhoGTPases, toll-interleukin receptor (TIR)-domain-containing adapter-inducing interferon-β (TRIF) and IFN-induction (IRF4, IRF7, IFI6, IFI27, IFI35, IFI44, SERPING1, OAS1, OAS2, OAS3, OASL, CXCL9, CXCL10, DDX58) pathways. Of note gene expression of IL27 was 2.7 times upregulated in MCNS patients in relapse. Consistent with the microarray results, plasma IL-27 levels were significantly higher in MCNS patients in relapse (1.56±0.19 pg/ml) compared to remission (0.95±0.13 pg/ml) (p<0.05) and controls (0.89±0.14 pg/ml) (p≤0.01). IL-27 stimulation in human podocytes resulted in phosphorylation of both STAT1 and STAT3. RhoA activity in IL-27 stimulated podocytes remained largely unchanged whereas activated Rac1 levels in podocytes were 1.56-fold higher compared with unstimulated podocytes at 20 minutes. Moreover, IL-27 induced 6.35% podocytes migration, comparable to the 6.96% podocytes migration observed in LPS-stimulated podocytes.

Conclusion

Monocytes may play a role in the pathogenesis of MCNS relapses via production of IL-27 and subsequent activation of STAT1, STAT3 and Rac1 as well as induction of cell migration in human podocytes.

Funding

  • Government Support - Non-U.S.