Regulation of gene expression in endothelial cells

Current work in our lab focuses upon newer aspects of the transcriptional and post-transcriptional regulation of endothelial gene expression in health and disease. Exciting new information indicates that chromatin structure and DNA methylation play a key role in the cell-restricted expression of important endothelial genes. Furthermore, RNA binding proteins and antisense RNA interactions also play an unexpected role in regulation of endothelial gene expression, in part, through modulation of RNA stability and translational efficiency. We suspect that these pathways may involve RNA interference. Epigenetic pathways and RNA interference are newer concepts in the regulation of genes in the cardiovascular system.

Models of Endothelial Activation
The study of endothelial cells has provided unique insight into important cardiovascular diseases and the control of angiogenesis during tumour development. The control of new blood vessel formation, or angiogenesis, is orchestrated by vascular endothelium and endothelial cells respond to unique signals in their environment with a repertoire of cellular and molecular responses. Studies directed towards dissecting the molecular mechanisms underlying alterations in genotype and phenotype are underway using prototypic endothelial cell gene products (e.g. endothelin-1, eNOS, CXCR4, adhesion molecules such as VCAM-1 or ICAM-1) and exciting models of cellular activation (hypoxia, shear stress and epigenetic modifiers). An excellent example of the applicability of this approach is our recent finding that verotoxins, bacterial-derived exotoxins that cause severe inflammation of capillary beds in patients with E coli 0157:H7, regulate the expression of genes in vascular endothelium at the post-transcriptional level through AUF1 and proteasomal pathways.

Regulated expression of nitric oxide (NO) in vascular tissue - role of epigenetics
Release of NO from the vascular endothelium represents a sensitive and highly effective local system for maintaining local blood flow to an organ. This research program played a major role in the cloning and functional characterization of endothelial NO synthase (eNOS) cDNAs and in the demonstratiion that expression of this endothelial gene is perturbed in atherosclerosis. Recent studies seek to define the structure and organization of the eNOS gene and examine mechanisms of regulation that are relevant to the pathobiology of endothelial cells. Current work focuses upon newer aspects of the transcriptional and post-transcriptional regulation of eNOS mRNA in development and disease.

Graduate Students:

Active

• Anna Gavryushova, MSc candidate
• Jr Jyun Ho, PhD candidate
• Apurva Shirodkar, PhD candidate
• Matthew Yan, PhD candidate

Selected References:

Link to Pubmed Publications

• Mawji, I.A., Robb, G.B., Tai, S.C., Marsden, P.A. Role of the 3-untranslated region of human endothelin-1 in vascular endothelial cells: Contribution to transcript lability and the cellular heat shock response. J Biol Chem, 279: 8655-67, 2004
  
  
• Chan, Y., Fish, J.E., DAbreo, C., Lin, S., Robb, G.B., Teichert, A.M., Karantzoulis-Fegaras, F., Keightley, A., Steer, B.M., Marsden, P.A. The cell-specific expression of endothelial nitric oxide synthase: a role for DNA methylation. J. Biol. Chem, 279: 35087-100, 2004
  
  Robb. G.B., Carson, A.R., Tai, S.C., Fish, J.E., Singh, S., Yamada, T., Scherer, S.W., Nakabayashi, K., Marsden, P.A. Post-transcriptional regulation of endothelial nitric oxide synthase by an overlapping antisense mRNA transcript. J. Biol. Chem,. 279: 37982- 96, 2004
  
  
• Fish, J.E., Matouk, C.C., Rachlis, A., Lin, S., Tai, S.C., DAbreo, C., Marsden, P.A. The expression of endothelial nitric oxide synthase is controlled by a cell-specific histone code. J Biol Chem. 280:24824-38, 2005
  
  
• Wang, Y., Vachon, E., Zhang, J., Cherepanov, V., Kruger, J., Li, J., Saito, K., Shannon, P.,  Bottini, N., Huynh, H., Ni, N., Yang, H., McKerlie, C., Quaggin, S., Zhao, Z.J., Marsden, P.A., Mustelin, T., Siminovitch. K.A., Downey. G.P. Tyrosine phosphatase MEG2 modulates murine development and platelet and lymphocyte activation through secretory vesicle function. J. Exp. Med. 202:1587-97, 2005
  
  
• Chan, G.C., Fish, J.E., Mawji, I.A., Leung, D.D., Rachlis, A.C., Marsden, P.A. Epigenetic basis for the transcriptional hyporesponsiveness of the human inducible nitric oxide synthase gene in vascular endothelial cells. J Immunol. 175: 3846-3861, 2005
  
  
• Ward, M.E., Toporsian, M., Scott, J.A., Teoh, H., Govindaraju, V., Wener, A., Bevan, S.C., Newton, D.C., Marsden, P.A. Hypoxia induces a functionally significant and transitionally efficient neuronal nitric oxide synthase mRNA variant. J Clin Invest. 115: 3128-3139, 2005
  
  
• Ding, M., Cui, S., Li, C., Jothy, S., Haase, V., Steer, B.M, Marsden, P.A., Pippin, J., Shankland, S., Rastaldi, M.P., Cohen, C.D., Kretzler, M., Quaggin, S.E. Loss of the tumor suppressor Vhlh leads to upregulation of Cxcr4 and rapidly progressive glomerulonephritis in mice. Nature Medicine, 12:1081-1087, 2006
  
  
• Fish, J.E., Matouk, C.C., Yeboah, E., Bevan, S.C., Khan, M., Patil, K., Ohh, M, Marsden, P.A. Hypoxia-inducible expression of a natural cis-antisense transcript inhibits endothelial nitric-oxide synthase. J Biol Chem, 282:15652-66, 2007
  
  
• Advani, A., Kelly, D.J., Advani, S.L., Cox, A.J., Thai, K., Zhang, Y., White, K.E., Gow, R.M., Marshall, S.M., Steer, B.M., Marsden, P.A., Rakoczy, P.E., Gilbert, R.E. Role of VEGF in maintaining renal structure and function under normotensive and hypertensive conditions. Proc Natl Acad Sci USA, 104(36):14448-14453, 2007
  
  
• Matouk, C.C., Marsden, P.A. Epigenetic regulation of vascular endothelial gene expression, Circ Res, 102:873-887, 2008
  
  
• Teichert, A.M., Scott, J.A., Robb, G.B, Zhou, Y.Q., Zhu, S., Lem, M., Keightley, A., Steer, B. M., Schuh, A. C., Adamson, S. L., Cybulsky, M. I., Marsden, P.A. Endothelial nitric oxide synthase (eNOS) gene expression during murine embryogenesis: commencement of expression occurs with the establishment of a unidirectional circulatory system. Circ Res 103: 24-33, 2008
  
  
• Wang, Y., Roche, O., Yan, M.S., Finak, G., Evans, A.J., Metcalf, J.L., Hast, B.E., Hanna, S.C., Wondergem, B., Furge, K.A., Irwin, M.S., Kim, W.Y., Teh, B.T., Grinstein, S., Park, M., Marsden, P.A., Ohh, M. Regulation of endocytosis via the oxygen-sensing pathway. Nature Medicine, 15:319-24, 2009