Related Experiment Videos
Astrocytic apolipoprotein E mRNA and GFAP mRNA in hippocampus after entorhinal cortex lesioning
1McGill Center For Studies In Aging, Montreal General Hospital, Que., Canada.
Abstract:
Entorhinal cortex lesions (ECL) that damage the perforant path to the hippocampus induce rapid increases of apolipoprotein E (apo E) mRNA in the hippocampus. Apo E mRNA was localized in astrocytes by in situ hybridization in combination with immunocytochemistry for glial fibrillary acidic protein (GFAP). Unilateral ECL also increased hippocampal GFAP mRNA, with increases preceding those of apo E mRNA. The apo E mRNA and GFAP mRNA responses were transiently bilateral in non-denervated zones. The timing of response in apo E mRNA to deafferentation supports suggestions that apo E has roles in membrane remodelling during responses to neuron injury.
Insights
Entorhinal cortex lesions increase apolipoprotein E (apo E) mRNA in astrocytes. This response, along with glial fibrillary acidic protein (GFAP) mRNA, suggests apo E’s role in repairing damaged brain membranes after injury.
Area of Science:
- Neuroscience
- Molecular Biology
- Astrocyte Biology
Background:
- Entorhinal cortex lesions (ECL) damage the perforant path to the hippocampus.
- These lesions rapidly increase apolipoprotein E (apo E) mRNA in the hippocampus.
Purpose of the Study:
- To investigate the cellular localization and temporal dynamics of apo E mRNA following entorhinal cortex lesions.
- To examine the role of astrocytes and glial fibrillary acidic protein (GFAP) in the response to neuronal injury.
Main Methods:
- In situ hybridization to localize apo E mRNA.
- Immunocytochemistry for glial fibrillary acidic protein (GFAP) to identify astrocytes.
- Analysis of mRNA expression changes in response to unilateral ECL.
Main Results:
- Apo E mRNA was localized in astrocytes within the hippocampus.
- Hippocampal GFAP mRNA increased following unilateral ECL, preceding apo E mRNA increases.
- Both apo E and GFAP mRNA responses were transiently bilateral in non-denervated zones.
Conclusions:
- Astrocytes are involved in the hippocampal response to entorhinal cortex lesions.
- The timing of apo E mRNA induction supports its role in membrane remodeling after neuronal injury.
- GFAP mRNA increases precede apo E mRNA, indicating an early astrocytic response to deafferentation.