MicroRNA expression in response to murine myocardial infarction: miR-21 regulates fibroblast metalloprotease-2 via phosphatase and tensin homologue.
OBJECTIVE
MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the post-transcriptional level by either degradation or translational repression of a target mRNA. Encoded in the genome of most eukaryotes, miRNAs have been proposed to regulate specifically up to 90% of human genes through a process known as miRNA-guided RNA silencing. For the first time, we sought to test how myocardial ischaemia-reperfusion (IR) changes miR expression.


RESULTS
Following 2 and 7 h of IR or sham operation, myocardial tissue was collected and subjected to miRNA expression profiling and quantification using a Bioarray system that screens for human-, mice-, rat-, and Ambi-miR. Data mining and differential analyses resulted in 13 miRs that were up-regulated on day 2, 9 miRs that were up-regulated on day 7, and 6 miRs that were down-regulated on day 7 post-IR. Results randomly selected from expression profiling were validated using real-time PCR. Tissue elements laser-captured from the infarct site showed marked induction of miR-21. In situ hybridization studies using locked nucleic acid miR-21-specific probe identified that IR-inducible miR-21 was specifically localized in the infarct region of the IR heart. Immunohistochemistry data show that cardiac fibroblasts (CFs) are the major cell type in the infarct zone. Studies with isolated CFs demonstrated that phosphatase and tensin homologue (PTEN) is a direct target of miR-21. Modulation of miR-21 regulated expression of matrix metalloprotease-2 (MMP-2) via a PTEN pathway. Finally, we noted a marked decrease in PTEN expression in the infarct zone. This decrease was associated with increased MMP-2 expression in the infarct area.


CONCLUSIONS
This work constitutes the first report describing changes in miR expression in response to IR in the mouse heart, showing that miR-21 regulates MMP-2 expression in CFs of the infarct zone via a PTEN pathway.
Roy
Sashwati
S
Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, 473 West 12th Avenue, Columbus, OH 43210, USA.
Khanna
Savita
S
Hussain
Syed-Rehan A
SR
Biswas
Sabyasachi
S
Azad
Ali
A
Rink
Cameron
C
Gnyawali
Surya
S
Shilo
Shani
S
Nuovo
Gerard J
GJ
Sen
Chandan K
CK
D000818:Animals; D002478:Cells, Cultured; D016000:Cluster Analysis; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000201:enzymology* / Q000473:pathology; D020869:Gene Expression Profiling / Q000379:methods; D015971:Gene Expression Regulation, Enzymologic; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000378:metabolism*; D009203:Myocardial Infarction / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D051059:PTEN Phosphohydrolase / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors
C531950:MIRN21 microRNA, mouse; D035683:MicroRNAs; D012333:RNA, Messenger; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase; C487757:Pten protein, mouse; D020778:Matrix Metalloproteinase 2; C522362:Mmp2 protein, mouse