Researchers Identify TIE2 as Key Link in Cerebral Cavernous Malformations Growth

Researchers at the Perelman School of Medicine at the University of Pennsylvania have identified the cell surface receptor protein TIE2 as a link between two signaling pathways implicated in the growth of cerebral cavernous malformations (CCMs). The study, to be published in the Journal of Experimental Medicine, suggests that drugs targeting TIE2 could potentially prevent the formation of CCMs.

Understanding Cerebral Cavernous Malformations (CCMs)

CCMs are blood vessel abnormalities that can lead to brain hemorrhages, strokes, and seizures. These vascular lesions occur in the central nervous system and are characterized by fragile blood vessels with thin walls. They affect approximately 1 in 200 people and can be caused by inherited or spontaneous gene mutations. Current treatment involves surgical removal, which is not always feasible due to the location of the malformations.

TIE2: A Crucial Link in Signaling Pathways

Mutations causing CCMs activate the MEKK3-KLF2/4 signaling pathway in endothelial cells, which subsequently stimulates the phosphoinositide 3-kinase (PI3K) pathway. Although PI3K pathway inhibitors have shown promise in preventing CCMs in mice, their systemic use in humans is associated with severe side effects, limiting long-term treatment options.

Mark L. Kahn, a professor at Penn and senior author of the study, stated that understanding the link between these pathways could identify a more specific therapeutic strategy.

The new research found that TIE2 activity was elevated in endothelial cells surrounding both human and mouse CCMs. Increased MEKK3-KLF2/4 signaling leads to higher levels of TIE2 protein, which in turn activates the PI3K pathway.

Potential for Targeted Treatment

Inhibiting TIE2 with rebastinib, an orally available drug, prevented the development of new CCMs in mice. These findings suggest that TIE2 blockade could offer a more targeted approach for chronic suppression of CCM growth, potentially reducing systemic side effects associated with broader PI3K pathway inhibition.