Abnormal reaction to central nervous system injury in mice lacking glial fibrillary acidic protein and vimentin

In response to injury of the central nervous system, astrocytes become reac tive and express high levels of the intermediate filament (IF) proteins gli al fibrillary acidic protein (GFAP), vimentin, and nestin. We have shown th at astrocytes in mice deficient for both GFAP and vimentin (GFAP-/-vim-/-) cannot form Ifs even when nestin is expressed and are thus devoid of Ifs in their reactive state. Here, we have studied the reaction to injury in the central nervous system in GFAP-/-, vimentin-/-, or GFAP-/-vim-/- mice. Glia l scar formation appeared normal after spinal cord or brain lesions in GFAP -/- or vimentin-/- mice, but was impaired in GFAP-/-vim-/- mice that develo ped less dense scars frequently accompanied by bleeding. These results show that GFAP and vimentin are required for proper glial scar formation in the injured central nervous system and that some degree of functional overlap exists between these IF proteins.