Responses of microRNAs 124a and 223 following spinal cord injury in mice.
METHODS
We investigated microRNA (miRNA) expression after spinal cord injury (SCI) in mice.


OBJECTIVE
The recent discovery of miRNAs suggests a novel regulatory control over gene expression during plant and animal development. MiRNAs are short noncoding RNAs that suppress the translation of target genes by binding to their mRNAs, and play a central role in gene regulation in health and disease. The purpose of this study was to examine miRNA expression after SCI.


METHODS
Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University.


METHODS
We examined the expression of miRNA (miR)-223 and miR-124a in a mouse model at 6 h, 12 h, 1 day, 3 days and 7 days after SCI using quantitative PCR. The miRNA expression was confirmed by in situ hybridization.


RESULTS
Quantitative PCR revealed two peaks of miR-223 expression at 6 and 12 h and 3 days after SCI. MiR-124a expression decreased significantly from 1 day to 7 days after SCI. In situ hybridization demonstrated the presence of miR-223 around the injured site. However, miR-124a, which was present in the normal spinal cord, was not observed at the injured site.


CONCLUSIONS
Our results indicate a time-dependent expression pattern of miR-223 and miR-124a in a mouse model of SCI. In this study, the time course of miRNA-223 expression may be related to inflammatory responses after SCI, and the time course of decreased miR-124a expression may reflect cell death.
Nakanishi
K
K
Department of Orthopaedic Surgery, Programs for Applied Biomedicine, Division of Clinical Medical Science, Graduate School of Biomedical, Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan.
Nakasa
T
T
Tanaka
N
N
Ishikawa
M
M
Yamada
K
K
Yamasaki
K
K
Kamei
N
N
Izumi
B
B
Adachi
N
N
Miyaki
S
S
Asahara
H
H
Ochi
M
M
D000818:Animals; D016923:Cell Death / Q000502:physiology; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000096:biosynthesis*; D009416:Nerve Regeneration / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000502:physiology; D013119:Spinal Cord Injuries / Q000378:metabolism*
C544877:MIRN223 microRNA, mouse; D035683:MicroRNAs; C540079:Mirn124 microRNA, mouse