William J. O'Brien, PhDWilliam J. O'Brien, PhD

Adjunct Professor of Ophthalmology

Research Synopsis

Research in the O'Brien Lab focuses on the pathogenesis and treatment of eye diseases caused by herpesviruses. Herpes simplex virus (HSV-1) is responsible for about 20,000 new and 400,000 recurrent eye infections each year in the United States. HSV infects the cornea causing epithelial lesions, stromal infiltrates and edema resulting in pain and impairment of vision or blindness. Therapy with antiviral agents reduces the duration of symptoms of acute disease but does not eradicate the virus (O'Brien et al 1996). Once infected, the virus becomes a permanent part of the host by establishing latent infections in the sensory nerves that serve the cornea. Studies in Dr. O'Brien's lab have documented that latent infections characterized by limited tissue specific gene expression are also established in corneal cells following or during acute disease (O'Brien et al 1998). It is unclear whether all reactivations of herpetic eye disease are due to reactivation from ganglionic latency or whether genomes persisting in the cornea play a role. Several studies of patients who have undergone penetrating keratoplasty now indicate that the genomes resident in the corneas of donors may transmit disease to recipients. Studies in the lab continue to characterize these persistent viral genomes.

Corneal edema which is due to loss of corneal endothelial cell function is a symptom that causes visual impairment during herpetic keratitis. The loss of function in some cases may be due to endothelial and or stromal cell necrosis or apoptosis. It has been hypothesized that undesirable aspects of the immune response are responsible for this form of corneal damage. Studies in Dr. O'Brien's laboratory have documented that corneal edema is likely due to inhibition of corneal endothelial cell Na+K+ ATPase, and that paracellular permeability remains intact (O'Brien et al 1996). The mechanism(s) that regulate endothelial cell Na+K+ ATPase function during HSV-induced edema may involve the proinflammatory cytokines TNF-α, IL1-ß, and IFN-γ which are produced in the cornea in response to HSV. These cytokines induce nitric oxide synthase and possibly cyclooxygenase II which may be involved in the production of edema (O'Brien et al, 2001). Studies are underway to examine the molecular mechanisms and to develop inhibitors of these enzymes as anti-inflammatory agents for use in the eye.

To function properly, the cornea must maintain the proper radius of curvature and clarity. Preserving these properties is complicated by environmental exposure to ultraviolet light as well as abrasions and infections. The cornea, as the principal source of refractive power, is often subjected to surgical procedures to improve or restore vision. All of these factors are capable of causing inflammation resulting in either transient or permanent corneal edema or scarring that compromise the ability to see clearly. Corneal diseases and injuries are the leading causes of visits to eye care clinicians and have compromised the vision of more than 250 million people worldwide, resulting in blindness in over 6 million. Additional studies in the O'Brien lab are aimed at maintaining corneal clarity during inflammation. Recent studies seek to characterize a newly identified group of proteins that are responsible for the production of superoxide by corneal cells (O'Brien et al 2006). Superoxide is one of a group of molecules referred to as reactive oxygen species (ROS). The lab is currently studying mechanisms by which corneal cells generate superoxide and the mechanism(s) through which superoxide affects the functions of corneal stromal cells. Studies examine the proteins composing a newly discovered protein complex called NADPH oxidase (O'Brien et al 2006). Knowledge of the structure of the proteins of the complex is a key in understanding how to regulate its activities. Future studies will determine the cellular location and the contribution of the complex to total cellular production of superoxide. Regulation of the activity of the complex is critical because over production of superoxide can be detrimental to cells and cell survival may be compromised if too little is produced. Survival of all the corneal cell types is critical to maintaining corneal function. We believe that superoxide plays a critical role in the mechanism(s) by which growth factors and cytokines influence corneal cells. We hypothesize that O2.- produced by corneal cells serves as an effecter of the cells own response to growth factors and cytokines. Superoxide may act directly or indirectly through the products of its reaction with other molecules such as nitric oxide or water. The aims of a current NIH grant under consideration are the following:

Characterize the NADPH oxidase complex in rabbit and human corneal stromal cells:

  1. Determine the isoform(s) of NOX produced in corneal stromal cells
  2. Determine the state of phosphorylation of p47 phox and examine the effects of p47 phox on activity on the complex
  3. Determine the cellular localization of the NADPH complex
  4. Assess the production of O2.- by NADPH oxidase in living cells relative to other enzymes involved in oxidative metabolism including xanthine oxidase, nitric oxide synthase 2 and complex I

Investigate the mechanisms that regulate the activity of the NADPH oxidase complex:

  1. Determine the effects of cytokines and growth factors on NADPH oxidase and O2.- production
  2. Determine the function of Rac in the production of O2.- by the corneal cell NADPH oxidase
  3. Examine the effects of regulators of activity such as arachidonic acid, corticosteroids and bacterial lipopolysaccharide on NADPH oxidase

Establish the mechanism(s) by which superoxide produced by NADPH oxidase mediates the anti-apoptotic/apoptotic activities of cytokines (interleukin-1ß, tumor necrosis factor-α and interferon-γ):

  1. Determine which cytokines are required to produce the cell type dependent anti-apoptotic/apoptotic effects

  2. Determine the source of superoxide that functions to exert an anti-apoptotic effect

  3. Determine whether superoxide inhibits pro-apoptotic factors or promotes production of cell survival factors

  4. Investigate the role of NADPH oxidase in stromal cell apoptosis and cell survival in the corneas of rabbits


  • PhD, Microbiology, Medical College of Wisconsin

Post Doctoral Training

  • Physiology and Ophthalmology, Medical College of Wisconsin

Current Research Interests

  • Pathogenesis of Herpetic Eye Diseases and Antiviral Agents

  • Regulation of gene expression in the cornea by cytokines

Honors and Society Memberships

  • Senior Investigator Award by Research to Prevent Blindness

  • Member, American Association for Advancement of Science

  • Member, Association for Research in Vision and Ophthalmology

  • Member, International Society for Antiviral Research

  • Member, American Society for Microbiology

  • Member, National Ocular Microbiology and Immunology Group

  • Member, Sigma Xi

Grant Review Panels

  • Fight for Sight-Prevent Blindness Review Board for Grant-In-Aid

  • March of Dimes Birth Defect Foundation

  • American Institute of Biological Sciences Peer Review Panel

  • National Aeronautics and Space Administration Peer Review Panel

  • Veterans Administration Merit Reviewer

  • Welcome Foundation UK

  • U.S. Civilian Research and Development Foundation

  • International Science and Technology Center (ISTC),

  • US Department of State

Recent Publications

Mainali L, Raguz M, O'Brien WJ, Subczynski WK. Properties of fiber cell plasma membranes isolated from the cortex and nucleus of the porcine eye lens. Exp Eye Res. 2012 Feb 2. [Epub ahead of print]

Han DP, O'Brien WJ, Higgins B. Biocompatibility of pooled human immunoglobulin (Gamunex 10%™) with ocular infusion solutions (BSS™ and BSS Plus™): an in vitro evaluation of a potential antitoxin treatment for infectious endophthalmitis. J Ocul Pharmacol Ther. 2011 Aug;27(4):343-6. Epub 2011 Jun 1.

Rizvi F, Heimann T, Herrnreiter A, O'Brien WJ. Mitochondrial dysfunction links ceramide activated HRK expression and cell death. PLoS One. 2011 Mar

O'Brien WJ, Heimann T, Rizvi F. NADPH oxidase expression and production of superoxide by human corneal stromal cells. Mol Vis. 2009 Dec 3;15:2535-43.

O'Brien WJ, Krema C, Heimann T, Zhao H. Expression of NADPH oxidase in rabbit corneal epithelial and stromal cells in culture. Invest Ophthalmol Vis Sci. 2006 Mar;47(3):853-63.

Ngamkitidechakul C, Warejcka DJ, Burke JM, O'Brien WJ, Twining SS. Sufficiency of the reactive site loop of maspin for induction of cell-matrix adhesion and inhibition of cell invasion. Conversion of ovalbumin to a maspin-like molecule. J Biol Chem. 2003 Aug 22;278(34):31796-806. Epub 2003 Jun 10.

Ngamkitidechakul C, Burke JM, O'Brien WJ, Twining SS. Maspin: synthesis by human cornea and regulation of in vitro stromal cell adhesion to extracellular matrix. Invest Ophthalmol Vis Sci. 2001 Dec;42(13):3135-41.

O'Brien WJ, Heimann T, Tsao LS, Seet BT, McFadden G, Taylor JL. Regulation of nitric oxide synthase 2 in rabbit corneal cells. Invest Ophthalmol Vis Sci. 2001 Mar;42(3):713-9.

Taylor JL, Unverrich D, O'Brien WJ, Wilcox KW. Interferon coordinately inhibits the disruption of PML-positive ND10 and immediate-early gene expression by herpes simplex virus. J Interferon Cytokine Res. 2000 Sep;20(9):805-15.

Chitambar CR, Wereley JP, Heiman T, Antholine WE, O'Brien WJ. Cellular adaptation to down-regulated iron transport into lymphoid leukaemic cells:
effects on the expression of the gene for ribonucleotide reductase. Biochem J. 2000 Feb 1;34