Urinary exosomal miR-146a as a marker of albuminuria, activity changes and disease flares in lupus nephritis.

Autores de INCLIVA

• Olga Martínez Arroyo

  Autor

• 

  Ana María Ortega Gutiérrez

  Autor

• 

  Miguel Angel Solis Salguero

  Autor

• 

  Felipe Javier Chaves Martínez

  Autor

• 

  Josep Redón Mas

  Autor

• 

  Mª Jose Forner Giner

  Autor

• 

  Raquel Cortés Vergaz

  Autor

Participantes ajenos a INCLIVA

• Perez-Hernandez, Javier
• Galera, Miriam

Grupos y Plataformas de I+D+i

• Grupo de Enfermedad Renal

  

  Leading Researcher

  Jose Luis Górriz Teruel

• Grupo de Estudio de Riesgo Cardiometabólico y Renal

  

  Established Researcher

  Raquel Cortés Vergaz

• Unidad de Genómica y Diabetes

  

  Established Researcher

  Felipe Javier Chaves Martínez

Abstract

BACKGROUND: Urinary exosomes, especially microRNAs (miRNAs) packaged within, are ideal sources of renal damage markers. We investigated the association between exosomal miR-146a, (anti-inflammatory regulator) and disease activity, proteinuria and systemic lupus erythematosus (SLE) flares over a 36-month follow-up period. METHODS: We isolated urinary exosomes from 41 SLE patients, 27 with lupus nephritis (LN) and 20 healthy controls, and exosomal miR-146a, quantified by the real-time quantitative polymerase chain reaction (RT-qPCR), was correlated with histological features in 13 renal biopsies. We also analysed the association between the exosomal miR-146a and TRAF6 axis. RESULTS: Exosomal miR-146a showed an inverse association with circulating C3 and C4 complement components, proteinuria, and with histological features such as chronicity index. This marker was able to identify LN with an AUC of 0.82 (p = 0.001). Basal exosomal miR-146a was associated with disease activity and proteinuria changes and was an independent marker of 36-month follow-up flares (OR 7.08, p = 0.02). Pathway analysis identified IRAK1 and TRAF6 as miR-146a target genes. Finally, in vitro experiments suggested that miR-146a exerts a protective effect through negative regulation of inflammation by suppressing IRAK1 and TRAF6. CONCLUSIONS: Urinary exosomal miR-146a levels are correlated with lupus activity, proteinuria and histological features, discriminating patients with LN and being a good baseline marker of SLE flares. We have identified a relevant biological miR-146a-TRAF6 axis association in LN renal fibrosis progression.

© 2020. Italian Society of Nephrology.

Keywords

• Disease flares; Exosomes; Lupus nephritis; Systemic lupus erythematosus; microRNA