ABSTRACT
Characterizing the in vivo biodistribution pattern and relative expression levels of oligonucleotide-based molecules such as mRNA, miRNA, siRNA, and anti-miRNAs in animal models, could be a helpful first-step in the successful development of therapeutic oligonucleotides. Here we describe a simple procedure called "Whole-Body Scanning PCR" (WBS-PCR), which combines the power of PCR with that of imaging. WBS-PCR relies on 384 well-defined extractions across a mouse whole-body section followed by a single dilution step which renders the lysates compatible with various qPCR-based assays. The in vivo biodistribution maps are generated by deconvoluting the qPCR data and converting it into a TissueView compatible image file which can be overlaid with an image of the whole-body section used for extractions. WBS-PCR is a flexible platform that can be adapted to other detection systems and thereby further expand the use of this technology.
Subject(s)
Gene Expression , Molecular Imaging/methods , Oligonucleotides/genetics , Oligonucleotides/metabolism , Polymerase Chain Reaction/methods , Whole Body Imaging/methods , Animals , Cryoultramicrotomy/methods , Mice , MicroRNAs/genetics , Models, Animal , Oligonucleotides/administration & dosage , RNA, Messenger/genetics , RNA, Ribosomal, 18S/genetics , RNA, Small Interfering/genetics , Rats , Real-Time Polymerase Chain Reaction/methods , Rodentia , Tissue DistributionABSTRACT
Efficient tissue-specific delivery is a crucial factor in the successful development of therapeutic oligonucleotides. Screening for novel delivery methods with unique tissue-homing properties requires a rapid, sensitive, flexible and unbiased technique able to visualize the in vivo biodistribution of these oligonucleotides. Here, we present whole body scanning PCR, a platform that relies on the local extraction of tissues from a mouse whole body section followed by the conversion of target-specific qPCR signals into an image. This platform was designed to be compatible with a novel RT-qPCR assay for the detection of siRNAs and with an assay suitable for the detection of heavily chemically modified oligonucleotides, which we termed Chemical-Ligation qPCR (CL-qPCR). In addition to this, the platform can also be used to investigate the global expression of endogenous mRNAs and non-coding RNAs. Incorporation of other detection systems, such as aptamers, could even further expand the use of this technology.
