Fibrinogen Interaction with Astrocyte ICAM-1 and PrPC Results in the Generation of ROS and Neuronal Death.
Many neuroinflammatory diseases, like traumatic brain injury (TBI), are associated with an elevated level of fibrinogen and short-term memory (STM) impairment. We found that during TBI, extravasated fibrinogen deposited in vasculo-astrocyte interfaces, which was associated with neurodegeneration and STM reduction. The mechanisms of this fibrinogen-astrocyte interaction and its functional role in neurodegeneration are still unclear. Cultured mouse brain astrocytes were treated with fibrinogen in the presence or absence of function-blocking antibody or peptide against its astrocyte receptors intercellular adhesion molecule-1 (ICAM-1) or cellular prion protein (PrPC), respectively. Fibrinogen interactions with astrocytic ICAM-1 and PrPC were characterized. The expression of pro-inflammatory markers, generations of reactive oxygen species (ROS) and nitric oxide (NO) in astrocytes, and neuronal death caused by astrocyte-conditioned medium were assessed. Data showed a strong association between fibrinogen and astrocytic ICAM-1 or PrPC, overexpression of pro-inflammatory cytokines and overproduction of ROS and NO, resulting in neuronal apoptosis and death. These effects were reduced by blocking the function of astrocytic ICAM-1 and PrPC, suggesting that fibrinogen association with its astrocytic receptors induce the release of pro-inflammatory cytokines, resulting in oxidative stress, and ultimately neuronal death. This can be a mechanism of neurodegeneration and the resultant STM reduction seen during TBI.
['Sulimai|Nurul|N|', 'Brown|Jason|J|', 'Lominadze|David|D|']
D000818:Animals D017209:Apoptosis D001253:Astrocytes D016923:Cell Death D002478:Cells, Cultured D005340:Fibrinogen D018799:Intercellular Adhesion Molecule-1 D051379:Mice D008810:Mice, Inbred C57BL D009474:Neurons D018621:PrPC Proteins D017382:Reactive Oxygen Species
ROS neuron pro-inflammatory markers NO apoptosis proximity ligation