University of California, Riverside

School of Medicine

Faculty Biographies

Iryna Ethell

Professor of Biomedical Sciences
Associate Dean, Academic Affairs

Iryna Ethell

University of California, Riverside
Riverside, CA 92521

Tel: (951) 827-2186
Fax: (951) 827-5504
Office: 2662 School of Medicine Education Building
Lab Office: 2269 Webber Hall

Education and Training

  • Ph.D., Dnipropetrovsk National University, Ukraine, 1991

Previous Institutions

  • Montreal Neurological Institute, McGill University, Canada, 1992-94
  • Max Planck Institute for Psychiatry, Munich, Germany, 1995-96
  • The Burnham Institute, La Jolla, 1996-2001

Research Summary

In our laboratory we are interested in understanding how neuronal networks develop in the brain, with the goal of applying this knowledge to the development of therapeutics for neurodevelopmental disorders associated with mental retardation and autism.  To this end, we are working to define molecular and cellular mechanisms that govern the formation of dendritic spines and their plasticity in the brain.  Dendritic spines are small protrusions on the surface of the dendrite that receive the majority of excitatory synapses in the brain and play a critical role in learning and memory.

Defects in dendritic spine morphology have been found in the brains of patients with neurodevelopmental disorders associated with mental retardation and autism, including Rett Syndrome, Down Syndrome, Angleman’s Syndrome and Fragile X Syndrome, that exhibit immature spine profiles. Moreover, dendritic spine loss is a hallmark of several neurodegenerative diseases and may contribute to impaired brain function in these diseases. However, little is known about the cellular and molecular mechanisms that govern dendritic spine development and maintenance.  Dendritic spines are very dynamics and can rapidly change in response to normal physiological and pathological stimuli. Our studies of the molecular and cellular factors that regulate actin assembly and remodeling within dendritic spines, may lead to therapeutics that can reverse abnormal dendritic spine development and prevent dendritic spine loss in neurodegenerative diseases.

This exciting new area of research is now combining with electrophysiology, pharmacology and neural network modeling to provide a unified model of the synaptogenesis within the brain, which will ultimately clarify our understanding of how the brain works.

Mouse Models

Fragile X mouse models, conditional and conventional gene knockouts.

Molecular Targets

EphB receptors and ephrins, integrins, neuroligins and neurexins, matrix metalloproteases, proteoglycans.

Cellular Interactions

Synaptic axon-dendritic and glia-neuron interactions, neuro-immune interactions (interactions between neurons and microglia).


Live imaging; confocal and two-photon microscopy, transfection of neurons in cultures and in slices, recombinant proteins, siRNA, transgenic mice, real time PCR, gene cloning, in situ, 2D-analysis, flow cytometry, subcellular fractionation, immunofluorescence, histochemistry, behavioral tests.

Current Lab Members
  • Lab Assistant: Ivan Trang
  • Postdoctoral Researcher: Dr. Sonia Afroz
  • Graduate Students: Jordan Koeppen, Amanda Nguyen, Teresa Wen, Sara Reinhard
  • Undergraduate Students: Michael Garcia, Kendal Tapia, Katherine Espinoza, Kasim Pendi, Vanna Wu, Simone Woodruff
Past Lab Members
  • Lab Assistant: Kelly Phommahaxay, Sima Mortazavi
  • Associate Specialist: Dr. Angeliki Nikolakopoulou
  • Postdoctoral Researchers: Dr. Tina Bilousova, Dr. Michael Moeller, Dr. Crystal Pontrello
  • Graduate Students: Lorraine Dansie, Slawomir Sloniowski, Crystal Pontrello, Kai-Ti Lin, Michelle Ngo, Yang Shi, Nai-Ying Yang, Harpreet Sidhu, Atena Zahedi
  • Undergraduate Students: Adrian Gamez, Ayodeji Okusanya, Devan Pandya, Jennifer Aye, Jessica Uwadia, Joshua Leish, Kelly Phommahaxay, Mike Huang, Mohamed Mohamed, Sadaf Sherzai

Selected Publications

  • Pontrello CG, Sun M-Y, Lin A, Fiacco TA, DeFea KA, and Ethell IM. 2012. Cofilin under control of β-arrestin-2 in NMDA-dependent dendritic spine plasticity, long-term depression (LTD), and learning. PNAS, 109(7):E442-51. Epub 2012 Jan 30.
  • Rotschafer SE, TrujilloMS, DansieLE, Ethell IM, RazakKA. 2011. Minocycline treatment reverses ultrasonic vocalization production deficit in a mouse model of Fragile X Syndrome. Brain Res., 1439:7-14. Epub 2011 Dec 31.
  • Sloniowski S, Ethell IM. 2011. Looking forward to EphB signaling in synapses. Seminars in Cell and Dev Biol. Oct 21. [Epub ahead of print].
  • Dansie L, Ethell IM. 2011. Casting a net on dendritic spines: The extracellular matrix and its receptors. Dev Neurobiol. 71(11): 956-981.
  • Cesa R, Premoselli F, Renna A, Ethell IM, Pasquale EB, Strata P. 2011. Eph receptors are involved in the activity-dependent synaptic wiring in the mouse cerebellar cortex. PLoS One. 6(4):e19160.
  • Paribello C, Tao L, Folino A, Berry-Kravis E, Tranfaglia M, Ethell IM, Ethell DW. 2010. Open-label add-on treatment trial of minocycline in fragile X syndrome. BMC Neurol. Oct 11: p10:91.
  • Utari, A., Chonchaiya, W., Rivera, S.M., Schneider, A., Hagerman, R.J., Faradz, S.M., Ethell, I.M., Nguyen, D.V. 2010. Side effects of minocycline treatment in patients with fragile x syndrome and exploration of outcome measures. Am J Intellect Dev Disabil. Vol. 115(5): p433-443.
  • Yang NY, Lopez-Bergami P, Goydos JS, Yip D, Walker AM, Pasquale EB, Ethell IM. 2010. The EphB4 receptor promotes the growth of melanoma cells expressing the ephrin-B2 ligand. Pigment Cell Melanoma Res. 23(5):684-687.
  • C. Pontrello and I. M. Ethell 2009. Accelerators, brakes, and gears of actin dynamics in dendritic spines. TONJ, 3: 67-86.
  • Y. Shi, C. Pontrello, K. Defea, L.F. Reichardt and I. M. Ethell 2009. Focal adhesion kinase acts downstream of EphB receptors to maintain mature dendritic spines by regulating cofilin activity. J. Neurosci., 29(25): 8075-8086.
  • T. Bilousova, L. Dansie, M. Ngo, J. Aye, J. R. Charles, D.W. Ethell and I. M. Ethell 2009. Minocycline Promotes Dendritic Spine Maturation and Improves Behavioral Performance in the Fragile X Mouse Model. J Med Gen., 46(2):94-102. Epub 2008 Oct 3.
  • K.-T. Lin, D.W. Ethell and I.M. Ethell 2008 Ephrin-B2-induced cleavage of EphB2 receptor is mediated by matrix metalloproteinases to trigger cell repulsion. J Biol Chem, 283(43):28969-28979. Epub 2008 Aug 19.
  • I.M. Ethell and D.W. Ethell 2007. Matrix Metalloproteinases in Brain Development and Remodeling: Synaptic Functions and Targets. J. Neurosci. Res. 85(13):2813-2823.
  • T. Bilousova, D. Rusakov, D.W. Ethell and I.M. Ethell 2006. MMP-7 Disrupts Dendritic Spines in Hippocampal Neurons through NMDA Receptor Activation. J. Neurochem. 97(1):44-56. Epub 2006 Mar 3.
  • Y. Shi and I.M. Ethell 2006. Integrins Control Dendritic Spine Plasticity in Hippocampal Neurons through NMDA Receptor and CaMKII-Mediated Actin Reorganization. J. Neurosci. 26(6):1813-1822.
  • M.L. Moeller, Y. Shi, L.F. Reichardt and I.M. Ethell 2006. EphB receptors regulate dendritic spine morphogenesis through the recruitment/phosphorylation of FAK and RhoA activation. J Biol Chem. 281(3):1587-98. Epub 2005 Nov 18.
  • C.C. Hoogenraad, A.D. Milstein, I.M. Ethell, M. Henkemeyer and M. Sheng 2005. GRIP1 controls dendrite morphogenesis by regulating EphB receptor trafficking. Nat Neurosci. 8(7):906-915.
  • I.M. Ethell and E.B. Pasquale 2005.  Molecular mechanisms of dendritic spine development and remodeling. Prog Neurobiol. 75(3):161-205. Epub 2005 Apr 2.
  • M. Henkemeyer, O.S. Itkis, M. Ngo, P.W. Hickmott and I.M. Ethell 2003.  Multiple EphB receptor tyrosine kinases shape dendritic spines in the hippocampus. J Cell Biol., 163(6):1313-1326.
  • I.M. Ethell, F. Irie, M.S.Kalo, J.R.Couchman, E.B. Pasquale and Y. Yamaguchi 2001. EphB2/syndecan-2 signaling in dendritic spine morphogenesis. Neuron, 31:  1001-1013.
  • H.-G. Wang, N. Pathan, I.M. Ethell, S. Krajewski, Y. Yamaguchi, F. Shibasaki, F. McKeon, T. Bobo, T.F. Franke and J.  Reed 1999. Ca-Induced apoptosis through calcineurin dephosphorylation of BAD. Science 284: 339-343.

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