Sequence and TLR9 independent increase of TRACP expression by antisense DNA and siRNA molecules.
Reactive oxygen species generating activity of tartrate-resistant acid phosphatase (TRACP) has been suggested to have several functions in TRACP expressing bone resorbing osteoclasts, macrophages, and dendritic cells. This work aimed to study the TRACP knock down phenotype in osteoclasts by using antisense DNA and RNA interference methods. Unexpectedly, both TRACP specific DNA oligonucleotides and siRNA molecules extensively increased the TRACP expression in human osteoclasts and monocytes. Toll-like receptor 9 (TLR9) is an immunity sensor for CpG motifs in DNA. We cultured bone marrow-derived osteoclast precursor cells from wild-type and TLR9-/- mice with CpG and non-CpG DNA oligonucleotides, and observed that the increased TRACP expression was sequence and TLR9 independent. In contrast, cells with increased TRACP activity showed decreased activity of tartrate-sensitive acid phosphatases.


CONCLUSIONS
DNA oligonucleotides and RNA molecules extensively increase TRACP expression in monocyte-macrophage lineage. These results suggest a potential role of TRACP in pathogen recognition and in innate immunity.
Muhonen
Pirkko
P
Institute of Biomedicine, Department of Anatomy, University of Turku, FIN-20520 Turku, Finland.
Avnet
Sofia
S
Parthasarathy
Ranga N
RN
Janckila
Anthony J
AJ
Halleen
Jussi M
JM
Laitala-Leinonen
Tiina
T
Väänänen
H Kalervo
HK
D000135:Acid Phosphatase / Q000378:metabolism*; D000818:Animals; D016466:CHO Cells; D002454:Cell Differentiation; D006224:Cricetinae; D003412:Cricetulus; D016373:DNA, Antisense / Q000235:genetics*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009000:Monocytes / Q000166:cytology* / Q000378:metabolism*; D010010:Osteoclasts / Q000166:cytology* / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics*; D000071681:Tartrate-Resistant Acid Phosphatase; D051217:Toll-Like Receptor 9 / Q000235:genetics / Q000378:metabolism*
D016373:DNA, Antisense; D007527:Isoenzymes; D034741:RNA, Small Interfering; C495370:Tlr9 protein, mouse; D051217:Toll-Like Receptor 9; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase