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Astrocytes in multiple sclerosis lack beta-2 adrenergic receptors
J De Keyser1, N Wilczak, R Leta
1Department of Neurology, Academisch Ziekenhuis Groningen, The Netherlands.
Neurology
|November 24, 1999
Summary
In multiple sclerosis (MS), astrocytes lack beta2 adrenergic receptors, which normally suppress major histocompatibility complex (MHC) class II expression. This absence may drive autoimmune responses in the brain.
Area of Science:
- Neuroimmunology
- Cellular immunology
Background:
- T cells in multiple sclerosis (MS) can trigger autoimmune responses by releasing cytokines.
- Glial cells, including astrocytes and microglia, present myelin antigens to T cells.
- Norepinephrine regulates astrocytic major histocompatibility complex (MHC) class II expression via beta2 adrenergic receptors.
Purpose of the Study:
- To investigate the expression of beta2 adrenergic receptors in astrocytes within the context of MS.
Main Methods:
- Immunocytochemical analysis of postmortem brain tissue from MS patients, cerebral infarction patients, and controls.
- Examination of spinal cord tissue from amyotrophic lateral sclerosis (ALS) patients.
Main Results:
- Beta2 adrenergic receptors were observed on astrocytes in control white matter and in reactive astrocytes in cerebral infarction and ALS.
- Astrocytic beta2 adrenergic receptors were absent in normal-appearing white matter and chronic active/inactive plaques in MS.
- MHC class II-positive astrocytes were found in chronic active plaques in MS, while neurons expressed beta2 adrenergic receptors.
Conclusions:
- The lack of astrocytic beta2 adrenergic receptors in MS may contribute to the induction or perpetuation of autoimmune reactions.
- This deficiency in receptor expression is linked to the inducibility of MHC class II molecules on astrocytes.