Published: November 28th, 2016
This protocol describes the isolation and quantification of high-density lipoprotein small RNAs.
The diversity of small non-coding RNAs (sRNA) is rapidly expanding and their roles in biological processes, including gene regulation, are emerging. Most interestingly, sRNAs are also found outside of cells and are stably present in all biological fluids. As such, extracellular sRNAs represent a novel class of disease biomarkers and are likely involved in cell signaling and intercellular communication networks. To assess their potential as biomarkers, sRNAs can be quantified in plasma, urine, and other fluids. Nevertheless, to fully understand the impact of extracellular sRNAs as endocrine signals, it is important to determine which carriers are transporting and protecting them in biological fluids (e.g., plasma), which cells and tissues contribute to extracellular sRNA pools, and cells and tissues capable of accepting and utilizing extracellular sRNA. To accomplish these goals, it is critical to isolate highly pure populations of extracellular carriers for sRNA profiling and quantification. We have previously demonstrated that lipoproteins, particularly high-density lipoproteins (HDL), transport functional microRNAs (miRNA) between cells and HDL-miRNAs are significantly altered in disease. Here, we detail a new protocol that utilizes tandem HDL isolation with density-gradient ultracentrifugation (DGUC) and fast-protein-liquid chromatography (FPLC) to obtain highly pure HDL for downstream profiling and quantification of all sRNAs, including miRNAs, using both high-throughput sequencing and real-time PCR approaches. This protocol will be a valuable resource for the investigation of sRNAs on HDL.
Extracellular non-coding small RNAs (sRNAs) represent a new class of disease biomarkers and potential therapeutic targets and likely facilitate cell-to-cell communication1. The most widely studied type of sRNA are microRNAs (miRNA) which are approximately 22 nts in length and are processed from longer precursor forms and primary transcripts2. miRNAs have been demonstrated to post-transcriptionally regulate gene expression through suppression of protein translation and induction of mRNA degradation2. Nevertheless, miRNAs are just one of many types of sRNAs; as sRNAs can be cleaved from parent tRNAs (tRNA-derived sRNAs, tDR), small nucle....
1. HDL Purification (~ 5.5 days)
This protocol is a series of established methods linked together to allow for the quantification of sRNAs on highly pure HDL by high-throughput sequencing or real-time PCR (Figure 1). To demonstrate the feasibility and impact of this protocol, HDL was purified from human plasma by the tandem DGUC and FPLC method. Collected FPLC fractions corresponding to HDL (by cholesterol distribution) were concentrated and total RNA was isolated from 1 mg of HDL (total protein). sRNA l.......
This protocol is designed to quantify miRNAs and other sRNAs by high-throughput sequencing or real-time PCR on highly pure HDL. As with any approach, special considerations should be given to each step in the process of purifying HDL and RNA and then quantifying sRNAs. This protocol is designed for projects starting with ≥ 2 mL of plasma. Nevertheless, high quality RNA analyses can successfully be completed with HDL purified from as little as 80 µL of human or mouse plasma using affinity chromatography; howeve.......
This work was supported by awards from the National Institutes of Health, National Heart, Lung and Blood Institute to K.C.V. HL128996, HL113039, and HL116263. This work was also supported by awards from the American Heart Association to K.C.V. CSA2066001, D.L.M POST26630003, and R.M.A. POST25710170.....
|AKTA Pure FPLC System
|3X FPLC Superdex 200 Increase Columns In-line
|5417R (purchased through USA Scientific)
|High Sensitivity DNA Assay
|Sequencing Library qPCR Quantification Kit
|ProFlex Thermal Cycler
|QuantStudio 12k Flex
|Ultra-clear centrifuge tubes
|15 mL conical tube
|Micro-centrifugal filters 0.45µm
|Micro-centrifugal filters 0.22µm
|miRNAEasy Total RNA Isolation Kits
|Total Cholesterol colormetric kit
|10,000 m.w. cut-off centrifugation filter
|purchased through Millipore
|PCR strip tubes
|purchased through Fisher
|microRNA RT kit
|For 1000 reactions
|PCR master mix
|50 mL bottle
|Pierce BCA kit
|Clean and Concentrator Kit
|purchased through Fisher
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