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Locked Nucleic Acid‐Based In Situ Hybridisation Reveals miR‐7a as a Hypothalamus‐Enriched Micro RNA with a Distinct Expression Pattern
Author(s) -
Herzer S.,
Silahtaroglu A.,
Meister B.
Publication year - 2012
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.2012.02358.x
Subject(s) - hypothalamus , rna , arcuate nucleus , biology , in situ hybridization , medicine , endocrinology , cocaine and amphetamine regulated transcript , supraoptic nucleus , orexigenic , gene expression , messenger rna , microbiology and biotechnology , neuropeptide , gene , neuropeptide y receptor , biochemistry , receptor
Micro RNA s (mi RNA s) are short (∼22 nucleotides) noncoding RNA molecules that post‐transcriptionally repress the expression of protein‐coding genes by binding to 3′‐untranslated regions of the target m RNA s. To identify mi RNA s selectively expressed within the hypothalamus, a part of the brain that controls vital bodily functions, we employed locked nucleic acid ( LNA )‐fluorescent in situ hybridisation ( FISH ). The expression pattern of the mature mi RNA s mi R ‐7a, mi R ‐7b, mi R ‐137 and mi R ‐153 in mouse brain tissue sections was investigated. Although all studied mi RNA s were present in the hypothalamus, mi R ‐7a, was the only mi RNA found to be enriched in the hypothalamus, with low or no expression in other parts of the central nervous system ( CNS ). Within the hypothalamus, strong mi R ‐7a expression was distinct and restricted to some hypothalamic nuclei and adjacent areas. mi R ‐7a expression was particularly prominent in the subfornical organ, as well as the suprachiasmatic, paraventricular, periventricular, supraoptic, dorsomedial and arcuate nuclei. Identical expression patterns for mi R ‐7a were seen in mouse and rat hypothalamus. By combining LNA ‐ FISH with immunohistochemistry, it was shown that mi R ‐7a was preferentially present in small orexigenic neuropeptide Y /agouti‐related protein‐containing‐neurones located in the ventromedial aspect of the arcuate nucleus but not in large pro‐opiomelanocortin/cocaine‐ and amphetamine‐regulated transcript‐containing anorexigenic neurones of the ventrolateral part of the arcuate nucleus. The limited and distinct expression of mi R ‐7a in the CNS suggests that mi R ‐7a has a role in post‐transcriptional regulation in hypothalamic neurones. Particularly strong expression of mi R ‐7a in neurones located in the ventromedial division of the arcuate nucleus, a subregion with a weak blood–brain barrier, raises the possibility that mi R ‐7a is influenced by circulating hormones and is a regulator of the genes involved in body weight control.