Macrophages overexpressing tartrate-resistant acid phosphatase show altered profile of free radical production and enhanced capacity of bacterial killing.
Activated macrophages and osteoclasts express high amounts of tartrate-resistant acid phosphatase (TRACP, acp5). TRACP has a binuclear iron center with a redox-active iron that has been shown to catalyze the formation of reactive oxygen species (ROS) by Fenton's reaction. Previous studies suggest that ROS generated by TRACP may participate in degradation of endocytosed bone matrix products in resorbing osteoclasts and degradation of foreign compounds during antigen presentation in activated macrophages. Here we have compared free radical production in macrophages of TRACP overexpressing (TRACP+) and wild-type (WT) mice. TRACP overexpression increased both ROS levels and superoxide production. Nitric oxide production was increased in activated macrophages of WT mice, but not in TRACP+ mice. Macrophages from TRACP+ mice showed increased capacity of bacterial killing. Recombinant TRACP enzyme was capable of bacterial killing in the presence of hydrogen peroxide. These results suggest that TRACP has an important biological function in immune defense system.
Räisänen
Seija R
SR
Institute of Biomedicine, Department of Anatomy, University of Turku, Turku, Finland.
Alatalo
Sari L
SL
Ylipahkala
Hannele
H
Halleen
Jussi M
JM
Cassady
A Ian
AI
Hume
David A
DA
Väänänen
H Kalervo
HK
D000135:Acid Phosphatase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D015870:Gene Expression; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008262:Macrophage Activation; D008264:Macrophages / Q000201:enzymology* / Q000276:immunology*; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000502:physiology; D013481:Superoxides / Q000378:metabolism*; D000071681:Tartrate-Resistant Acid Phosphatase
D007527:Isoenzymes; D017382:Reactive Oxygen Species; D013481:Superoxides; D009569:Nitric Oxide; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase