Circulating and Urinary microRNAs in Kidney Disease

Abstract

Summary microRNAs are small, noncoding RNAs that control gene/protein expression through target messengerRNA degradation and/or inhibition of protein synthesis. An array of experimental studies has shown the importance of microRNAs for disease initiation/progression. microRNAs are generally considered to act as intracellular modulators of gene expression. However, first studies in the cancer and cardiovascular field have elucidated that microRNAs are remarkably stable in the extracellular compartment (e.g., in blood or urine). The detection and quantification of circulating microRNAs may, thus, represent a novel noninvasive tool to detect and monitor disease activity. In addition, there might be a potential biologic relevance of circulating microRNAs for cell/cell communication. The aim of the present article is to give an outline of recent work on circulating and urinary microRNAs as well as their potential paracrine activity in kidney disease.

Urinary MicroRNA as Biomarker in Renal Transplantation

“…MicroRNAs are 19–23‐nucleotide‐long noncoding single‐stranded RNA molecules that act as regulators of gene expression 11. Precursor microRNAs, known as pri‐microRNAs, are generated by RNA polymerase II and have as hallmark 5′ and 3′ poly‐A tails.…”

MicroRNAs in Idiopathic Childhood Nephrotic Syndrome

“…In last few years, however, several studies have revealed the remarkable stability of extracellular miRNAs circulating in the blood or excreted in the urine and underscored their key importance as biomarkers of certain diseases (10,11 ). Intriguingly, circulating miRNAs may also modulate cellular transcriptional events by transferring genetic information from a donor cell to a recipient cell (12 ). The stability of circulating miRNAs depends on several critical mechanisms of miRNA transport, without which they are degraded by plasma RNAses within minutes (12 ).…”

“…Intriguingly, circulating miRNAs may also modulate cellular transcriptional events by transferring genetic information from a donor cell to a recipient cell (12 ). The stability of circulating miRNAs depends on several critical mechanisms of miRNA transport, without which they are degraded by plasma RNAses within minutes (12 ). Circulating miRNAs are protected from degradation by inclusion into lipid or lipoprotein complexes, such as microvesicles/microparticles or exosomes (12 ).…”

“…The stability of circulating miRNAs depends on several critical mechanisms of miRNA transport, without which they are degraded by plasma RNAses within minutes (12 ). Circulating miRNAs are protected from degradation by inclusion into lipid or lipoprotein complexes, such as microvesicles/microparticles or exosomes (12 ). Additionally, miRNAs may be stabilized by binding to RNA-binding proteins such as Argonaute 2 (12 ).…”

“…Circulating miRNAs are protected from degradation by inclusion into lipid or lipoprotein complexes, such as microvesicles/microparticles or exosomes (12 ). Additionally, miRNAs may be stabilized by binding to RNA-binding proteins such as Argonaute 2 (12 ). Endothelial apoptotic bodies released upon cell damage and subsequent apoptosis induction may also transport circulating miRNAs (12 ).…”