Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

The cerebral cavernous malformation signaling pathway promotes vascular integrity via Rho GTPases

A Corrigendum to this article was published on 01 April 2009

This article has been updated


Cerebral cavernous malformation (CCM) is a common vascular dysplasia that affects both systemic and central nervous system blood vessels. Loss of function mutations in the CCM2 gene cause CCM. Here we show that targeted disruption of Ccm2 in mice results in failed lumen formation and early embryonic death through an endothelial cell autonomous mechanism. We show that CCM2 regulates endothelial cytoskeletal architecture, cell-to-cell interactions and lumen formation. Heterozygosity at Ccm2, a genotype equivalent to that in human CCM, results in impaired endothelial barrier function. On the basis of our biochemical studies indicating that loss of CCM2 results in activation of RHOA GTPase, we rescued the cellular phenotype and barrier function in heterozygous mice with simvastatin, a drug known to inhibit Rho GTPases. These data offer the prospect for pharmacological treatment of a human vascular dysplasia with a widely available and safe drug.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1: Ccm2 is required for blood circulation.
Figure 2: Vascular defects in mutant mice are endothelial cell autonomous.
Figure 3: CCM2 is required for endothelial tube morphogenesis.
Figure 4: CCM2 deficiency alters the endothelial cytoskeletal architecture and cell-cell interactions via activation of the small GTPase RHOA.
Figure 5: Heterozygous Ccm2+/tr mice have permeability defects that can be rescued by treatment with simvastatin.

Change history

  • 06 April 2009

    In the version of this article initially published, Christopher A. Jones and Weiquan Zhu were not included in the list of authors. The error has been corrected in the HTML and PDF versions of the article.


  1. Otten, P., Pizzolato, G.P., Rilliet, B. & Berney, J. A propos de 131 cas d'angiomes caverneux (cavernomes) du S.N.C. repérés par l'analyse rétrospective de 24 535 autopsies. Neurochirurgie 35, 82–83 128–131 (1989).

    CAS  Google Scholar 

  2. Robinson, J.R., Awad, I.A. & Little, J.R. Natural history of the cavernous angioma. J. Neurosurg. 75, 709–714 (1991).

    Article  CAS  Google Scholar 

  3. Hasegawa, T. et al. Long-term results after stereotactic radiosurgery for patients with cavernous malformations. Neurosurgery 50, 1190–1197 discussion 1197–1198 (2002).

    PubMed  Google Scholar 

  4. Chappell, P.M., Steinberg, G.K. & Marks, M.P. Clinically documented hemorrhage in cerebral arteriovenous malformations: MR characteristics. Radiology 183, 719–724 (1992).

    Article  CAS  Google Scholar 

  5. Clatterbuck, R.E., Eberhart, C.G., Crain, B.J. & Rigamonti, D. Ultrastructural and immunocytochemical evidence that an incompetent blood-brain barrier is related to the pathophysiology of cavernous malformations. J. Neurol. Neurosurg. Psychiatry 71, 188–192 (2001).

    Article  CAS  Google Scholar 

  6. Toldo, I., Drigo, P., Mammi, I., Marini, V. & Carollo, C. Vertebral and spinal cavernous angiomas associated with familial cerebral cavernous malformation. Surg. Neurol. published online, doi:10.1016/j.surneu.2007.07.067 (22 January 2008).

  7. Liquori, C.L. et al. Mutations in a gene encoding a novel protein containing a phosphotyrosine-binding domain cause type 2 cerebral cavernous malformations. Am. J. Hum. Genet. 73, 1459–1464 (2003).

    Article  CAS  Google Scholar 

  8. Denier, C. et al. Mutations within the MGC4607 gene cause cerebral cavernous malformations. Am. J. Hum. Genet. 74, 326–337 (2004).

    Article  CAS  Google Scholar 

  9. Sahoo, T. et al. Mutations in the gene encoding KRIT1, a Krev-1/rap1a binding protein, cause cerebral cavernous malformations (CCM1). Hum. Mol. Genet. 8, 2325–2333 (1999).

    Article  CAS  Google Scholar 

  10. Laberge-le Couteulx, S. et al. Truncating mutations in CCM1, encoding KRIT1, cause hereditary cavernous angiomas. Nat. Genet. 23, 189–193 (1999).

    Article  CAS  Google Scholar 

  11. Bergametti, F. et al. Mutations within the programmed cell death 10 gene cause cerebral cavernous malformations. Am. J. Hum. Genet. 76, 42–51 (2005).

    Article  CAS  Google Scholar 

  12. Uhlik, M.T. et al. Rac-MEKK3–MKK3 scaffolding for p38 MAPK activation during hyperosmotic shock. Nat. Cell Biol. 5, 1104–1110 (2003).

    Article  CAS  Google Scholar 

  13. Petit, N., Blecon, A., Denier, C. & Tournier-Lasserve, E. Patterns of expression of the three cerebral cavernous malformation (CCM) genes during embryonic and postnatal brain development. Gene Expr. Patterns 6, 495–503 (2006).

    Article  CAS  Google Scholar 

  14. Plummer, N.W. et al. Neuronal expression of the Ccm2 gene in a new mouse model of cerebral cavernous malformations. Mamm. Genome 17, 119–128 (2006).

    Article  CAS  Google Scholar 

  15. Seker, A. et al. CCM2 expression parallels that of CCM1. Stroke 37, 518–523 (2006).

    Article  CAS  Google Scholar 

  16. McCarty, J.H. et al. Selective ablation of αv integrins in the central nervous system leads to cerebral hemorrhage, seizures, axonal degeneration and premature death. Development 132, 165–176 (2005).

    Article  CAS  Google Scholar 

  17. Glading, A., Han, J., Stockton, R.A. & Ginsberg, M.H. KRIT-1/CCM1 is a Rap1 effector that regulates endothelial cell cell junctions. J. Cell Biol. 179, 247–254 (2007).

    Article  CAS  Google Scholar 

  18. Risau, W. Mechanisms of angiogenesis. Nature 386, 671–674 (1997).

    Article  CAS  Google Scholar 

  19. Su, H., Mills, A.A., Wang, X. & Bradley, A. A targeted X-linked CMV-Cre line. Genesis 32, 187–188 (2002).

    Article  CAS  Google Scholar 

  20. Kisanuki, Y.Y. et al. Tie2-Cre transgenic mice: a new model for endothelial cell-lineage analysis in vivo. Dev. Biol. 230, 230–242 (2001).

    Article  CAS  Google Scholar 

  21. Sclafani, A.M. et al. Nestin-Cre mediated deletion of Pitx2 in the mouse. Genesis 44, 336–344 (2006).

    Article  CAS  Google Scholar 

  22. Lepore, J.J. et al. High-efficiency somatic mutagenesis in smooth muscle cells and cardiac myocytes in SM22α-Cre transgenic mice. Genesis 41, 179–184 (2005).

    Article  CAS  Google Scholar 

  23. Kamei, M. et al. Endothelial tubes assemble from intracellular vacuoles in vivo. Nature 442, 453–456 (2006).

    Article  CAS  Google Scholar 

  24. Bayless, K.J. & Davis, G.E. Microtubule depolymerization rapidly collapses capillary tube networks in vitro and angiogenic vessels in vivo through the small GTPase Rho. J. Biol. Chem. 279, 11686–11695 (2004).

    Article  CAS  Google Scholar 

  25. Wojciak-Stothard, B., Potempa, S., Eichholtz, T. & Ridley, A.J. Rho and Rac but not Cdc42 regulate endothelial cell permeability. J. Cell Sci. 114, 1343–1355 (2001).

    CAS  PubMed  Google Scholar 

  26. Mohr, C., Koch, G., Just, I. & Aktories, K. ADP-ribosylation by Clostridium botulinum C3 exoenzyme increases steady-state GTPase activities of recombinant rhoA and rhoB proteins. FEBS Lett. 297, 95–99 (1992).

    Article  CAS  Google Scholar 

  27. Hirose, M. et al. Molecular dissection of the Rho-associated protein kinase (p160ROCK)-regulated neurite remodeling in neuroblastoma N1E–115 cells. J. Cell Biol. 141, 1625–1636 (1998).

    Article  CAS  Google Scholar 

  28. Kyriakis, J.M. & Avruch, J. Sounding the alarm: protein kinase cascades activated by stress and inflammation. J. Biol. Chem. 271, 24313–24316 (1996).

    Article  CAS  Google Scholar 

  29. Jung, K.H. et al. Cerebral cavernous malformations with dynamic and progressive course: correlation study with vascular endothelial growth factor. Arch. Neurol. 60, 1613–1618 (2003).

    Article  Google Scholar 

  30. Larson, J.J., Ball, W.S., Bove, K.E., Crone, K.R. & Tew, J.M.,, Jr. Formation of intracerebral cavernous malformations after radiation treatment for central nervous system neoplasia in children. J. Neurosurg. 88, 51–56 (1998).

    Article  CAS  Google Scholar 

  31. Shi, C., Shenkar, R., Batjer, H.H., Check, I.J. & Awad, I.A. Oligoclonal immune response in cerebral cavernous malformations. Laboratory investigation. J. Neurosurg. 107, 1023–1026 (2007).

    Article  CAS  Google Scholar 

  32. Gault, J., Shenkar, R., Recksiek, P. & Awad, I.A. Biallelic somatic and germ line CCM1 truncating mutations in a cerebral cavernous malformation lesion. Stroke 36, 872–874 (2005).

    Article  Google Scholar 

  33. Zeng, L. et al. HMG CoA reductase inhibition modulates VEGF-induced endothelial cell hyperpermeability by preventing RhoA activation and myosin regulatory light chain phosphorylation. FASEB J. 19, 1845–1847 (2005).

    Article  CAS  Google Scholar 

  34. Park, H.J. et al. 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors interfere with angiogenesis by inhibiting the geranylgeranylation of RhoA. Circ. Res. 91, 143–150 (2002).

    Article  CAS  Google Scholar 

  35. Kranenburg, O., Poland, M., Gebbink, M., Oomen, L. & Moolenaar, W.H. Dissociation of LPA-induced cytoskeletal contraction from stress fiber formation by differential localization of RhoA. J. Cell Sci. 110, 2417–2427 (1997).

    CAS  PubMed  Google Scholar 

  36. Collisson, E.A., Carranza, D.C., Chen, I.Y. & Kolodney, M.S. Isoprenylation is necessary for the full invasive potential of RhoA overexpression in human melanoma cells. J. Invest. Dermatol. 119, 1172–1176 (2002).

    Article  CAS  Google Scholar 

  37. Im, E. & Kazlauskas, A. Src family kinases promote vessel stability by antagonizing the Rho/ROCK pathway. J. Biol. Chem. 282, 29122–29129 (2007).

    Article  CAS  Google Scholar 

  38. Mavria, G. et al. ERK-MAPK signaling opposes Rho-kinase to promote endothelial cell survival and sprouting during angiogenesis. Cancer Cell 9, 33–44 (2006).

    Article  CAS  Google Scholar 

  39. Whitehead, K.J., Plummer, N.W., Adams, J.A., Marchuk, D.A. & Li, D.Y. Ccm1 is required for arterial morphogenesis: implications for the etiology of human cavernous malformations. Development 131, 1437–1448 (2004).

    Article  CAS  Google Scholar 

  40. Davis, G.E. & Camarillo, C.W. An α2β1 integrin-dependent pinocytic mechanism involving intracellular vacuole formation and coalescence regulates capillary lumen and tube formation in three-dimensional collagen matrix. Exp. Cell Res. 224, 39–51 (1996).

    Article  CAS  Google Scholar 

  41. Saunders, W.B. et al. Coregulation of vascular tube stabilization by endothelial cell TIMP-2 and pericyte TIMP-3. J. Cell Biol. 175, 179–191 (2006).

    Article  CAS  Google Scholar 

Download references


We thank C. Colvin, C. Jones, W. Zhu and A. Frias for technical assistance; M. Sanguinetti, S. Odelberg and I. Benjamin for critical comments; M. Kahn, K. Thomas, M. Ginsberg and R. Stockton for helpful scientific discussions; and A. Hall (Memorial Sloan-Kettering Cancer Center) for GTPase complementary DNA constructs. This work was funded by the US National Institutes of Health (K.J.W., D.A.M., G.E.D. and D.Y.L.), including training grant T32-GM007464 (A.C.C.) and a Ruth L. Kirschstein National Research Service award (N.R.L.), the American Heart Association (K.J.W. and D.Y.L.), the H.A. and Edna Benning Foundation, the Juvenile Diabetes Research Foundation, the Burroughs Wellcome Fund and the Flight Attendants Medical Research Institute (D.Y.L.).

Author information

Authors and Affiliations


Corresponding authors

Correspondence to Kevin J Whitehead or Dean Y Li.

Ethics declarations

Competing interests

The University of Utah has filed patents on the basis of the results reported in this paper.

Supplementary information

Supplementary Text and Figures

Supplementary Figs. 1 and 2, Supplementary Table 1 and Supplementary Methods (PDF 746 kb)

Supplementary Movies 1

Fetal ultrasound of Ccm2+/+ embryo at E8.8. Circulating blood is observed (moving pixels) in the dorsal aorta and the yolk sac vessels of the embryo. (MOV 547 kb)

Supplementary Movies 2

Fetal ultrasound of Ccm2tr/tr embryo at E8.8. No circulating blood is observed, despite normal frequency of cardiac contractions. (MOV 486 kb)

Supplementary Movies 3

Time-lapse photography of luciferase control siRNA treated HUVECs. Observation over 24 h shows the formation of intracellular vacuoles that coalesce into multicellular networks with lumens. (MOV 4239 kb)

Supplementary Movies 4

Time-lapse photography of CCM2 siRNA–treated HUVECs. Observation over 24 h shows impairment of vacuole and lumen formation in cells depleted of CCM2. (MOV 4657 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Whitehead, K., Chan, A., Navankasattusas, S. et al. The cerebral cavernous malformation signaling pathway promotes vascular integrity via Rho GTPases. Nat Med 15, 177–184 (2009).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing