ICAM-1 related long noncoding RNA is associated with progression of IgA nephropathy and fibrotic changes in proximal tubular cells

Intercellular adhesion molecule 1 (ICAM-1) related long noncoding RNA (ICR) is on the antisense strand of ICAM-1 and regulates ICAM-1 expression. ICAM-1 is involved in renal tubulointerstitial injury; however, the expression and clinical implication of ICR are not determined in IgA nephropathy (IgAN). We compared renal ICR levels in 337 IgAN patients with those of 89 biopsy controls, and a markedly increased ICR level was observed in IgAN patients. By Cox proportional hazards models, higher levels of renal ICR were independently associated with disease progression event defined as end-stage renal disease or >= 40% decline in estimated glomerular filtration rate. Patients in the highest tertile of renal ICR had a 3.5-fold higher risk for disease progression compared with those in the lowest tertile. The addition of renal ICR to a model with traditional risk factors improved risk prediction of disease progression (net reclassification index: 0.31 [95% CI 0.01-0.50]; integrated discrimination index: 0.10 [95% CI 0.04-0.16]). Inhibition of ICR by transfection with plasmids containing ICR shRNA significantly reduced expression of collagen I and alpha-SMA, and phosphorylation of Akt and mTOR in TGF-beta 1- treated HK-2 cells. Our findings suggest that renal ICR might be an independent predictor of IgAN progression and contribute to renal fibrosis.

Automated summary

Increased levels of renal ICR are independently associated with disease progression in IgA nephropathy and improve risk prediction of disease progression.