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Mannose receptor is present in a functional state in rat microglial cells
M P Marzolo1, R von Bernhardi, N C Inestrosa
1Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
Abstract:
We studied the expression of the mannose receptor (ManR) in rat microglial cells. Microglial cells are the central nervous system resident macrophages, key participants of the innate immune response. ManR is a differentiation marker and a relevant glycoprotein for the phagocytic and endocytic function of macrophages. Because there is evidence suggesting that ManR could mediate some of the nonenzymatic effects of acetilcholinesterase (AchE) and the enzyme seems to be involved in Alzheimer's disease (AD), we looked for ManR in microglia, evaluating the functionality of the receptor. We isolated microglial cells from the brain of 2-day-old neonatal rats. Microglial cells, identified by their specific staining with the lectin Griffonia simplicifolia, expressed ManR, being detected by immunocytochemistry, Western blot, and immunoprecipitation. Microglial ManR was downregulated by lipopolysaccharide (LPS) and upregulated by dexamethasone, as described for peripheral macrophages. Microglial ManR was functional and able to internalize horseradish peroxidase (HRP), a known ManR ligand, in a mannan-inhibitable manner. The presence of a functional ManR in microglia opens the possibility that ManR could participate in multiple physiologic and pathologic conditions in the central nervous system (CNS), including inflammation, ischaemia, and neurodegenerative diseases such as AD.
Insights
Mannose receptor (ManR) is present and functional in rat microglial cells. This finding suggests ManR
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglial cells are key immune cells in the central nervous system (CNS).
- The mannose receptor (ManR) is crucial for macrophage phagocytic and endocytic functions.
- Evidence links acetylcholinesterase (AchE) to Alzheimer's disease (AD), with potential ManR involvement.
Purpose of the Study:
- To investigate the expression and functionality of ManR in rat microglial cells.
- To explore ManR's role in CNS physiological and pathological processes.
Main Methods:
- Isolation of microglial cells from neonatal rat brains.
- Detection of ManR using immunocytochemistry, Western blot, and immunoprecipitation.
- Assessment of ManR functionality via horseradish peroxidase (HRP) internalization assays.
Main Results:
- Rat microglial cells express ManR, confirmed by multiple detection methods.
- Microglial ManR expression is modulated by lipopolysaccharide (LPS) and dexamethasone.
- Functional ManR in microglia mediates HRP uptake in a mannan-sensitive manner.
Conclusions:
- Microglial cells possess a functional mannose receptor.
- ManR in microglia may play a role in CNS inflammation, ischemia, and neurodegenerative diseases like AD.