MicroRNAs: new biomarkers and promising therapeutic targets for diabetic kidney disease / MicroRNAs: novos biomarcadores e alvos terapêuticos promissores da doença renal do diabetes

Abstract Diabetic kidney disease (DKD) is a chronic complication of diabetes mellitus associated with significant morbidity and mortality regarded as a global health issue. MicroRNAs - small RNA molecules responsible for the post-transcriptional regulation of gene expression by degradation of messenger RNA or translational repression of protein synthesis - rank among the factors linked to the development and progression of DKD. This study aimed to offer a narrative review on investigations around the use of microRNAs in the diagnosis, monitoring, and treatment of DKD. Various microRNAs are involved in the pathogenesis of DKD, while others have a role in nephroprotection and thus serve as promising therapeutic targets for DKD. Serum and urine microRNAs levels have also been considered in the early diagnosis and monitoring of individuals with DKD, since increases in albuminuria, decreases in the glomerular filtration rate, and progression of DKD have been linked to changes in the levels of some microRNAs.

Resumo A doença renal do diabetes (DRD) é uma complicação crônica do diabetes mellitus associada à elevada morbidade e mortalidade, considerada um problema de saúde mundial. Dentre os fatores associados ao desenvolvimento e à progressão da DRD, destacam-se os microRNAs, que consistem em pequenas moléculas de RNA que regulam a expressão gênica por meio da degradação pós-transcricional do RNA mensageiro ou inibição translacional da síntese proteica. Este estudo teve como objetivo realizar uma revisão narrativa buscando investigar os microRNAs como auxiliares no diagnóstico, monitoramento e tratamento da DRD. Vários microRNAs estão envolvidos na patogênese da DRD, enquanto que outros têm papel nefroprotetor, consistindo assim em alvos terapêuticos promissores para o tratamento da DRD. A dosagem laboratorial dos microRNAs no soro e na urina também é muito promissora para o diagnóstico precoce e o monitoramento da DRD, já que os níveis de alguns microRNAs se alteram antes do aumento da albuminúria e da diminuição da taxa de filtração glomerular e podem ainda se alterar com a progressão da DRD.

Upregulation of microRNA 142-3p in the peripheral blood and urinary cells of kidney transplant recipients with post-transplant graft dysfunction

We analyzed microRNA (miR)-142-3p expression in leucocytes of the peripheral blood and urinary sediment cell samples obtained from kidney transplant recipients who developed graft dysfunction. Forty-one kidney transplant recipients with kidney graft dysfunction and 8 stable patients were included in the study. The groups were divided according to histological analysis into acute rejection group (n=23), acute tubular necrosis group (n=18) and stable patients group used as a control for gene expression (n=8). Percutaneous biopsies were performed and peripheral blood samples and urine samples were obtained. miR-142-3p was analyzed by real-time polymerase chain reaction. The group of patients with acute tubular necrosis presented significantly higher expressions in peripheral blood (P<0.05) and urine (P<0.001) compared to the stable patients group. Also, in the peripheral blood, miR-142-3p expression was significantly higher in the acute tubular necrosis group compared to the acute rejection group (P<0.05). Urine samples of the acute rejection group presented higher expression compared to the stable patients group (P<0.001) but the difference between acute tubular necrosis and acute rejection groups was not significant in the urinary analyzes (P=0.079). miR-142-3p expression has a distinct pattern of expression in the setting of post-operative acute tubular necrosis after kidney transplantation and may potentially be used as a non-invasive biomarker for renal graft dysfunction.