Differential expression of peroxiredoxin subtypes in human brain cell types

The peroxiredoxin (Prx) protein is expressed widely in animal tissues and s erves an antioxidant function associated with removal of cellular peroxides , We have cloned two Prx genes and observed differential expression of Prx- I and Prx-II (formerly NKEF-A and NKEF-B) in purified rat brain cell cultur es (Sarafian et al, [1998] Mel. Chem, Neuropathol, 34:39-51), We have exami ned regional and cell-type-specific expression df Prx-I and Prx-II in paraf fin sections of human brain using immunohistochemical methods. These studie s revealed a clear segregation of expression of these two gene products in different brain cell types, In the cerebral cortex, cerebellum, basal gangl ia, substantia nigra, and spinal cord, Prx-I was expressed primarily in ast rocytes, while Prx-II was expressed exclusively in neurons, Prx-I was also prominently expressed in ependymal cells and subependymal matrix of substan tia nigra and basal ganglia, Prx-II was not expressed at uniform density in all neurons. In general,. small neurons such as cerebellar granule neurons displayed little or no staining, while large neurons, such as hippocampal pyramidal and Purkinje neurons were heavily stained, The absence of express ion of Prx-I in neurons and the selective expression of Prx-II in large neu rons suggest that these antioxidant enzymes serve distinct functional roles that may reflect the different functions and biochemical activities of the se cell types. Restricted expression of these genes may also contribute to the selective vulnerability of these cells to a wide variety of neuropathol ogic conditions. J. Neurosci, Res, 56:206-212, 1999, (C) 1999 Wiley-Liss, I nc.