Increased DJ-1 expression under oxidative stress and in Alzheimer's disease brains
1 Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Harvard University, Boston, MA 02115, USA
2 Harriet and John Wooten Laboratory of Alzheimer's Disease Research, The Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
3 Department of Anatomy and Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
4 Departments of Neurology and Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8813, USA
Molecular Neurodegeneration 2009, 4:12 doi:10.1186/1750-1326-4-12Published: 25 February 2009
Mutations in the DJ-1 gene have been linked to autosomal recessive familial Parkinson's disease. To understand the function of DJ-1, we determined the DJ-1 expression in both zebrafish and post mortem human brains. We found that DJ-1 was expressed early during zebrafish development and throughout adulthood. Knock down (KD) of DJ-1 by injection of morpholino did not cause dramatic morphologic alterations during development, and no loss of dopaminergic neurons was observed in embryos lacking DJ-1. However, DJ-1 KD embryos were more susceptible to programmed cell death. While a slight reduction in staining for islet-1 positive neurons was observed in both DJ-1 KD and H2O2 treated embryos, the number of apoptotic cells was significantly increased in both KD and H2O2 treated embryos. Interestingly, DJ-1 expression was increased in brains of zebrafish under conditions of oxidative stress, indicating that DJ-1 is a part of stress-responsive machinery. Since oxidative stress is one of the major contributors to the development of Alzheimer's disease (AD), we also examined DJ-1 expression in AD brains. Using DJ-1 specific antibodies, we failed to detect a robust staining of DJ-1 in brain tissues from control subjects. However, DJ-1 immunoreactivity was detected in hippocampal pyramidal neurons and astrocytes of AD brains. Therefore, our results strongly suggest that DJ-1 expression is not necessary during zebrafish development but can be induced in zebrafish exposed to oxidative stress and is present in human AD brains.