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Dr. Siobhan McMahon

Senior Investigator
+353 91 492838
Astrocytes in scar tissue
Dorsal Root Ganglia
Neural Stem Cells and Oligodendrocytes

Lecturer in Dept. of Anatomy, NUIG

Siobhan explores the use of stem cells and gene therapy in treatment of nerve regeneration and glial scarring.

Researcher in

Research Project Area: 

Lentiviral vector delivery of siRNA and neurotrophic growth factors for the treatment of injury to the CNS:

Lentiviral vectors are an efficient and effective way to deliver therapeutic genes. When CNS injury occurs a glial scar is formed resulting in a highly inhibitory environment for the growth of axons. This inhibitory environment is mainly due to chondroitin sulphate proteoglycans (CSPG). This project involves treatment of the glial scar with lentiviral vectors to reduce scar formation and promote secretion of neurotrophic factors.

Regeneration of injured spinal cord neurons through implantable polymer bridges using a combined approach of neurotrophic support and glial scar inhibition:

Tissue engineering offers a realistic hope of restoring functional tissue following spinal cord injury. This project encompasses polymer scaffold bioengineering, mesenchymal stem cell (MSC) and retroviral gene therapy technologies for spinal cord repair. The central hypothesis is that axonal regeneration from spinal cord neurons can be regionally regulated by manipulation of the structural, molecular and cellular microenvironment in the spinal cord.

Role of neural stem (NS) cells in improving nerve regeneration:

Spinal cord injury is a devastating injury that impacts drastically on the victim’s quality of life. NS cells have been proposed as a therapeutic strategy for this traumatic injury. Stereological methods are being used to estimate the engraftment, migration and differentiation of NS cells and their potential role in promoting nerve regeneration.

Effect of Cyclosporin A (CsA) on nerve regeneration:

Considerable evidence has shown that the immunosuppressant drug CsA may have neuroprotective properties which can be exploited in the treatment of spinal cord injury. The aim of this study is to determine whether CsA has an effect on altering cellular interactions to promote a growth permissive environment for axonal regeneration.

Positions Held: 

Lecturer in Anatomy
Department of Anatomy, NUI Galway
Use of stem cells and gene therapy in treatment of nerve regeneration and glial scarring

Postdoctoral research fellow
Lentiviral vectors as tools in treatment of nerve injury

Postdoctoral research fellow
Department of Anatomy, University College Cork
Developmental potential of spinal cord radial glia 

1999                                                                                            PhD in Neuroanatomy, University College Cork

Awards & Honours: 

June 2004
Awarded EMBO short term fellowship to visit lab in US

1998, 2003, 2004
Awarded 3 first prize poster awards

Team Members: 
Selected Publications: 

Current tissue engineering and novel therapeutic approaches to axonal regeneration following spinal cord injury using polymer scaffolds. Madigan NN, McMahon S, O'Brien T, Yaszemski MJ, Windebank AJ. Respir Physiol Neurobiol. 2009 Nov 30;169(2):183-99. Epub 2009 Sep 6. PMID: 19737633

Effect of cyclosporin A on functional recovery in the spinal cord following contusion injury. McMahon SS, Albermann S, Rooney GE, Moran C, Hynes J, Garcia Y, Dockery P, O'Brien T, Windebank AJ, Barry FP. J Anat. 2009 Sep;215(3):267-79. Epub 2009 Jun 24. PMID: 19558472

Neurotrophic factor-expressing mesenchymal stem cells survive transplantation into the contused spinal cord without differentiating into neural cells. Rooney GE, McMahon SS, Ritter T, Garcia Y, Moran C, Madigan NN, Flügel A, Dockery P, O'Brien T, Howard L, Windebank AJ, Barry FP. Tissue Eng Part A. 2009 Oct;15(10):3049-59. PMID: 19335061

Gene-Modified Mesenchymal Stem Cells Express Functionally Active Nerve Growth Factor on an Engineered Poly Lactic Glycolic Acid (PLGA) Substrate.  Rooney GE, Moran C, McMahon SS, Ritter T, Maenz M, Flügel A, Dockery P, O'Brien T, Howard L, Windebank AJ, Barry FP. Tissue Eng Part A. 2008 Apr 11.

Developmental potential of radial glia investigated by transplantation into the developing rat ventricular system in utero.
McMahon SS, McDermott KW. Exp Neurol. 2007 Jan;203(1):128-36..

A comparison of cell transplantation and retroviral gene transfection as tools to study lineage and differentiation in the rat spinal cord.
McMahon SS, McDermott KW. J Neurosci Methods. 2006 Apr 15;152(1-2):243-9.

Role of radial glia in cytogenesis, patterning and boundary formation in the developing spinal cord.
McDermott KW, Barry DS, McMahon SS. J Anat. 2005 Sep;207(3):241-50.

Estimation of nuclear volume as an indicator of maturation of glial precursor cells in the developing rat spinal cord: a stereological approach. McMahon SS, Dockery P, McDermott KW. J Anat. 2003 Sep;203(3):339-44.

Morphology and differentiation of radial glia in the developing rat spinal cord. McMahon SS, McDermott KW. J Comp Neurol. 2002 Dec 16;454(3):263-71.
Proliferation and migration of glial precursor cells in the developing rat spinal cord. McMahon SS, McDermott KW. J Neurocytol. 2001 Sep-Oct;30(9-10):821-8.

Professional and Personal Interests: 

Dept. of Anatomy, NUIG profile

Professional Memberships

Neuroscience Ireland
Anatomical Society of Great Britain and Ireland
Irish Society for Gene and Cell Therapy
European Society of Gene and Cell Therapy
Society for Neuroscience

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