1.Introduction
MiRNAs are a class of small, endogenous, non-coding RNAs approximately
18 to 25 nucleotides in length, which regulate the gene expression at
the transcriptional level (1, 2). More than 50% of the mammalian
protein-coding genes are regulated by miRNAs(1). In addition, miRNAs are
widely involved in ischemia reperfusion IR injury, innate and adaptive
immune responses, inflammatory response and cancer (3, 4). Although
studies have demonstrated that miRNAs can regulate target gene
expression following lung transplantation (LT) (5), global study
identified the differentially expressed (DE) miRNAs in response to IR
injury following LT.
Recently, millions of short sequence reads were identified using
Illumina high-throughput sequencing (HiSeq) (6, 7). Moreover, the
technique has been widely used to detect the miRNA expression profile in
several species and shown high-quality results in identification of
known and novel miRNAs. The HiSeq platform can also be used to predict
the target genes and their corresponding biological functions (8).
MiRNA-122, a liver-specific miRNA, has been known to reduce the
invasiveness and metastasis in non-small cell lung cancer (NECLC) (9).
The expression of miRNA-122 has been reported to be significantly
elevated during liver IR injury (10).Similarly, our previous studies
have reported increased expression of miRNA-122 following LT. However,
the functional role and the underlying molecular mechanisms of miRNA-122
in IR injury following LT remain unclear.
Toll-like receptors (TLRs) are highly conserved molecules that are
abundantly presented on the surface of several inflammatory cells
including alveolar macrophages, endothelial cells, and dendritic cells.
MiRNAs are known to can regulate the inflammatory process through the
TLR signaling pathway (11, 12). In addition, TLRs contribute to
inflammation during IR injury (13) and are associated with acute lung
injury (14). In the present study, we explored the functions of
miRNA-122 and the TLR pathway in IR injury following LT using a mouse
model.