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Expression and distribution of low density lipoprotein receptor-related protein mRNA in the rat central nervous
M Ishiguro1, Y Imai, S Kohsaka
1Department of Neurochemistry, National Institute of Neuroscience, Tokyo, Japan.
Abstract:
The low density lipoprotein receptor-related protein (LRP) is a multifunctional cell surface receptor that binds to the protease inhibitor alpha 2-macroglobulin (alpha 2 M). LRP has also been identified as the apolipoprotein E (apoE) receptor that mediates lipid metabolism. Recently it has been reported that apoE4, one of three common isoforms of apoE, is a main risk factor of Alzheimer's disease (AD). Moreover, all three of these proteins are reported to accumulate in the senile plaques in the brains of Alzheimer's patients. To understand the roles of LRP in the normal development of the central nervous system (CNS) and in the pathogenesis of AD, we studied the developmental expression and localization of LRP mRNA in the CNS. We used Northern blot analysis to investigate the developmental profile of LRP mRNA in the rat brain. LRP mRNA was first detected as early as in 18-day-old embryonic rat brain and was continuously expressed thereafter. A particularly high level of expression of the mRNA was observed in the perinatal stage. We also determined the cellular distribution of LRP mRNA in the CNS of 20-day-old embryonic and 6-week-old adult rat brains by in situ hybridization using a digoxigenin-labeled antisense riboprobe to LRP mRNA. In the embryonic rat brain, LRP mRNA was highly expressed in most of the cells, mainly neurons and glial cells. In the adult rat, LRP mRNA was expressed mostly in neurons in both the brain and the spinal cord. These results suggest that LRP plays crucial roles in development of the brain.
Insights
Low density lipoprotein receptor-related protein (LRP) is crucial for central nervous system development. LRP mRNA expression is high in embryonic and perinatal stages, primarily in neurons and glial cells, suggesting vital developmental roles.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Low density lipoprotein receptor-related protein (LRP) is a multifunctional cell surface receptor involved in various biological processes.
- LRP acts as an apolipoprotein E (apoE) receptor, mediating lipid metabolism and implicated in Alzheimer's disease (AD) due to apoE4's risk factor status.
- LRP, apoE, and alpha 2-macroglobulin (alpha 2 M) accumulate in senile plaques in Alzheimer's patients' brains.
Purpose of the Study:
- To investigate the role of LRP in normal central nervous system (CNS) development.
- To understand LRP's involvement in the pathogenesis of Alzheimer's disease (AD).
- To examine the developmental expression and localization of LRP mRNA within the CNS.
Main Methods:
- Northern blot analysis was employed to study the developmental profile of LRP mRNA in rat brains.
- In situ hybridization using a digoxigenin-labeled antisense riboprobe was used to determine the cellular distribution of LRP mRNA.
- Experiments were conducted on embryonic (20-day-old) and adult (6-week-old) rat brains and spinal cords.
Main Results:
- LRP mRNA was detected as early as embryonic day 18 in rat brains and showed continuous expression thereafter.
- A particularly high level of LRP mRNA expression was observed during the perinatal stage.
- In embryonic brains, LRP mRNA was highly expressed in neurons and glial cells; in adult brains and spinal cords, expression was predominantly in neurons.
Conclusions:
- The developmental expression pattern of LRP mRNA suggests a significant role in brain development.
- LRP's widespread expression in neurons and glial cells during critical developmental periods highlights its importance in CNS formation.
- Further research into LRP's function could provide insights into neurodevelopmental disorders and Alzheimer's disease.