For what factors should we normalize urinary extracellular mRNA biomarkers?

James Matthew Luther,James Brian Byrd,Pradeep Moon Gunasekaran

doi:10.1016/j.bdq.2019.100090

James Matthew Luther, James Brian Byrd + Show 1 more

Open Access

https://doi.org/10.1016/j.bdq.2019.100090

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Abstract

mRNA is a critical biomolecule involved in the manifestation of the genetic code into functional protein molecules. Its critical role in the central dogma has made it a key target in many studies to determine biomarkers and drug targets for numerous diseases. Currently, there is a growing body of evidence to suggest that RNA molecules around the size of full-length mRNA transcripts can be assayed in the supernatant of human urine and urinary extracellular mRNA could provide information about transcription in cells of urogenital tissues. However, the optimal means of normalizing these signals is unclear. In this paper, we describe relevant first principles as well as research findings from our lab and other labs toward normalization of urinary extracellular mRNA.

Highlights

Several species of RNA including messenger RNA are measurable in the supernatant of human urine [1]
Has long RNA in the size range of fulllength messenger RNA (mRNA) been extracted from urinary extracellular vesicles [5], mRNA present in an ultracentrifugation-derived pellet of extracellular vesicles from human urine has undergone massively parallel sequencing, aligning to approximately 13,500 genes [1]
This article focuses on explaining the first principles we find relevant to the question of normalizing urinary extracellular mRNA biomarkers

Summary

Introduction

Several species of RNA including messenger RNA (mRNA) are measurable in the supernatant of human urine [1]. Has long RNA in the size range of fulllength mRNA been extracted from urinary extracellular vesicles [5], mRNA present in an ultracentrifugation-derived pellet of extracellular vesicles from human urine has undergone massively parallel sequencing, aligning to approximately 13,500 genes [1]. Urinary extracellular vesicle-associated RNA has been sequenced (with the caveat that RNA shuttled by non-vesicular carriers is technically difficult to exclude in such studies) This RNA has been explored as a potential biomarker with promising results [5,7,8], and a company is offering a clinical assay they describe [9] as a “urine exosome gene expression assay.”. Whether the lack of explanatory value of the urinary creatinine will generalize to other studies remains to be seen

Using urine specific gravity to normalize for changes in urine osmolality

Findings

Conclusion