Dataset Information

Immune gene expression in kidney biopsies of lupus nephritis patients at diagnosis and at renal flare.

ABSTRACT:

Background

Up to 50% of lupus nephritis (LN) patients experience renal flares after their initial episode of LN. These flares contribute to poor renal outcomes. We postulated that intrarenal immune gene expression is different in flares compared with de novo LN, and conducted these studies to test this hypothesis.

Methods

Glomerular and tubulointerstitial immune gene expression was evaluated in 14 patients who had a kidney biopsy to diagnose LN and another biopsy at their first LN flare. Ten healthy living kidney donors were included as controls. RNA was extracted from laser microdissected formalin-fixed paraffin-embedded kidney biopsies. Gene expression was analyzed using the Nanostring nCounter® platform and validated by quantitative real-time polymerase chain reaction. Differentially expressed genes were analyzed by the Ingenuity Pathway Analysis and Panther Gene Ontology tools.

Results

Over 110 genes were differentially expressed between LN and healthy control kidney biopsies. Although there was considerable molecular heterogeneity between LN biopsies at diagnosis and flare, for about half the LN patients gene expression from the first LN biopsy clustered with the repeated LN biopsy. However, in all patients, a set of eight interferon alpha-controlled genes had a significantly higher expression in the diagnostic biopsy compared with the flare biopsy. In contrast, nine tumor necrosis factor alpha-controlled genes had higher expression in flare biopsies.

Conclusions

There is significant heterogeneity in immune-gene expression of kidney tissue from LN patients. There are limited but important differences in gene expression between LN flares, which may influence treatment decisions.

SUBMITTER: Mejia-Vilet JM

PROVIDER: S-EPMC7967887 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Publications

Immune gene expression in kidney biopsies of lupus nephritis patients at diagnosis and at renal flare.

Mejia-Vilet Juan M JM Parikh Samir V SV Song Huijuan H Fadda Paolo P Shapiro John P JP Ayoub Isabelle I Yu Lianbo L Zhang Jianying J Uribe-Uribe Norma N Rovin Brad H BH

Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 20190701 7

<h4>Background</h4>Up to 50% of lupus nephritis (LN) patients experience renal flares after their initial episode of LN. These flares contribute to poor renal outcomes. We postulated that intrarenal immune gene expression is different in flares compared with de novo LN, and conducted these studies to test this hypothesis.<h4>Methods</h4>Glomerular and tubulointerstitial immune gene expression was evaluated in 14 patients who had a kidney biopsy to diagnose LN and another biopsy at their first LN ...[more]

PMID: 29800348

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Project description:We aimed to identify miRNA biomarkers of renal injury in kidney biopsies from patients with lupus nephritis. MiRNA profiles of 8 patients were analyzed for correlation with various clinical features including Progression, Activity, Chronicity, and Time to Kidney Failure. MicroRNAs (miRs) are promising biomarkers and are involved in pathogenesis of kidney diseases. We aimed to identify miR biomarkers of renal injury in kidney biopsies from patients with lupus nephritis and study their potential role in renal fibrosis. miR-150 was significantly increased in kidneys with high chronicity compared to low chronicity and it correlated positively with chronicity index scores and renal collagen I expression. In kidneys with high chronicity, miR-150 was found predominantly in proximal tubular cells (PTCs) and was moderately expressed in podocytes and to lesser degree in mesangial cells (MCs). We hypothesized that miR-150 increases fibrosis by downregulating a negative regulator of profibrotic proteins. Suppressor of cytokine signaling1 (SOCS1) is a predicted target of miR-150 and has shown antifibrotic role. After confirming that SOCS1 is a direct target of miR-150, we showed that transfection of a miR-150 analog downregulated SOCS1 protein and upregulated the profibrotic proteins fibronectin, collagen I, collagen III, and TGF-β1 in both primary normal human renal PTCs and MCs. A similar effect was seen when using a SOCS1 siRNA to confirm that the effect of miR-150 on profibrotic proteins is mediated through SOCS1. Stimulation with TGF-β1 induced miR-150 increase in PTCs and human podocytes but not MCs. These results suggest that miR-150 might be a useful quantitative renal biomarker of kidney injury in lupus nephritis and that miR-150, which might be partially induced by TGF-β1, plays an important role in renal fibrosis by increasing profibrotic molecules through downregulation of SOCS1. FFPE kidney specimens (n=25) including baseline and repeated needle renal biopsies were from 14 patients with LN enrolled in IRB-approved protocols at the NIDDK between 1976 and 1999. The specimens were divided in two groups based on histological chronicity index (CI). CI ≥ 4 were categorized as having high degree of chronicity of chronic kidney injury. 18 kidneys from 8 patients including high CI (n=9) and low CI (n=9) were used for miR profiling by Affymetrix microRNA microarrays.

Project description:In lupus nephritis (LN), kidney inflammation may be followed by fibrosis and progressive decline in function. Transforming growth factor (TGF)-? is a notable mediator of fibrosis, but it has other beneficial roles, thus indicating a need for alternate therapeutic targets for inhibition of fibrosis. Connective tissue growth factor (CTGF) acts as a downstream mediator of TGF-? in promoting fibrosis, without mediating the immunosuppressive effects of TGF-?. Animal studies show that CTGF may have important roles in renal fibrosis, but data are limited in human subjects. The present study tested the hypothesis that renal CTGF mRNA expression is related to TGF-?1 and collagen I expression and is predictive of renal function deterioration in patients with LN (n=39). Gene expression was measured using multiplex real-time quantitative RT-PCR and renal function was estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) glomerular filtration rate (GFR) equation. Decline in GFR was assessed by regression of GFR at biopsy to 1 year following biopsy. CTGF mRNA expression was significantly correlated with TGF-?1 and collagen I. GFR at biopsy was 89.2±39.2 ml/ min. Renal CTGF mRNA expression correlated inversely with baseline GFR. Renal CTGF mRNA was significantly higher in patients with moderate to severe CKD compared to those in the milder CKD group (low GFR 4.92±4.34 vs. high GFR 1.52±1.94, p<0.005). CTGF mRNA was also higher in patients with subsequent decline in GFR [GFR decline (5.19±4.46) vs. no GFR decline (1.79±1.97); P<0.01]. In conclusion, renal expression of CTGF was positively related to TGF-?1 and collagen I in patients with LN. Furthermore, high CTGF mRNA expression was associated with poor GFR at baseline and subsequent deterioration of kidney function. CTGF expression in the kidney may serve as an early marker for renal disease progression and could be evaluated as a target for therapeutic intervention to prevent renal failure in LN.

Dataset Information

Immune gene expression in kidney biopsies of lupus nephritis patients at diagnosis and at renal flare.

Background

Methods

Results

Conclusions

Publications

Immune gene expression in kidney biopsies of lupus nephritis patients at diagnosis and at renal flare.

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