Synaptic localization of seizure-induced matrix metalloproteinase-9 mRNA
F A Konopacki1, M Rylski, E Wilczek
1Department of Neurophysiology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland.
Abstract:
The phenomenon of dendritic transport and local translation of mRNA is considered to be one of the most fundamental mechanisms underlying long-term synaptic plasticity. Matrix metalloproteinase 9 (gelatinase B) (MMP-9) is a matrix metalloproteinase implicated in synaptic long-term potentiation and hippocampus-dependent memory. It was recently shown to be prominently up-regulated in the hippocampal dentate gyrus (DG) upon kainate-mediated seizures. Here, using a high resolution nonradioactive in situ hybridization at the light- and electron-microscopic levels, as well as subcellular fractionation, we provide evidence that in the rat hippocampus, MMP-9 mRNA is associated with dendrites and dendritic spines bearing asymmetric (excitatory) synapses. Moreover we observe that after kainate treatment the number of dendrites and synapses containing MMP-9 mRNA increases markedly. Our results indicate that we are observing the phenomenon of dendritic transport of seizure-induced MMP-9 mRNA.
Insights
Matrix metalloproteinase 9 (MMP-9) mRNA is transported to dendrites and synapses in the rat hippocampus. Seizures increase the amount of MMP-9 mRNA in these neuronal structures, suggesting a role in synaptic plasticity.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Dendritic transport and local mRNA translation are crucial for long-term synaptic plasticity.
- Matrix metalloproteinase 9 (gelatinase B) (MMP-9) is involved in synaptic long-term potentiation and memory.
- MMP-9 is upregulated in the hippocampus following seizures.
Purpose of the Study:
- To investigate the subcellular localization and transport of MMP-9 mRNA in the rat hippocampus.
- To determine if MMP-9 mRNA transport is affected by seizure activity.
Main Methods:
- High-resolution nonradioactive in situ hybridization at light and electron microscopic levels.
- Subcellular fractionation techniques.
- Kainate administration to induce seizures in rats.
Main Results:
- MMP-9 mRNA is localized in dendrites and dendritic spines with asymmetric synapses in the rat hippocampus.
- Kainate treatment significantly increases the number of dendrites and synapses containing MMP-9 mRNA.
- Evidence supports dendritic transport of seizure-induced MMP-9 mRNA.
Conclusions:
- MMP-9 mRNA undergoes dendritic transport in the hippocampus.
- Seizure activity enhances the transport of MMP-9 mRNA to dendrites and synapses.
- This mechanism may contribute to synaptic plasticity and memory processes following seizures.
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