MMP9 and brain aneurysm: We have previously found that TNF-α can activate a number of pro-inflammatory and matrix remodeling genes in cerebral vascular smooth muscle cells directly implicated in cerebral aneurysm formation, including: MMP-3, MMP-9, MCP-1, VCAM-1, and IL-1β [8]; and IL-1β, VCAM-1 and MCP-1 [9,26,27].