Activation of nuclear factor kappaB and induction of inducible nitric oxide synthase by lipid-associated membrane proteins isolated from Mycoplasma penetrans.
BACKGROUND
This study was designed to investigate the potential pathogenicity of Mycoplasma penetrans (M. penetrans) and its molecular mechanisms responsible for the induction of iNOS gene expression in mouse macrophages stimulated by lipid-associated membrane proteins (LAMPs) prepared from M. penetrans.


METHODS
Mouse macrophages were stimulated with M. penetrans LAMPs to assay the production of nitric oxide (NO). The expression of inducible nitric oxide synthase (iNOS) was detected by RT-PCR and Western blotting. The activity of nuclear factor kappaB (NF-kappaB) and the effects of pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-kappaB, on the production of nitric oxide and the expression of iNOS were also assessed in mouse macrophages treated with M. penetrans LAMPs by indirect immunofluorescence and Western blotting.


RESULTS
M. penetrans LAMPs stimulated mouse macrophages to produce nitric oxide in a dose- and time-dependent manner. The mRNA and protein levels of iNOS were also upregulated in response to LAMP stimulation and inhibited by PDTC treatment. M. penetrans LAMPs were found to trigger NF-kappaB activation, a possible mechanism for the induction of iNOS expression.


CONCLUSIONS
This study demonstrated that M. penetrans may be an important etiological factor of certain diseases due to the ability of M. penetrans LAMPs to stimulate the expression of iNOS, which is probably mediated through the activation of NF-kappaB.
Zeng
Yan-hua
YH
Department of Microbiology, Medical College, Nanhua University, Hengyang 421001, China.
Wu
Yi-mou
YM
Zhang
Wen-bo
WB
Yu
Min-jun
MJ
Zhu
Cui-ming
CM
Tan
Li-zhi
LZ
D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology*; D002478:Cells, Cultured; D004790:Enzyme Induction; D008074:Lipoproteins / Q000494:pharmacology*; D008565:Membrane Proteins / Q000494:pharmacology*; D051379:Mice; D018661:Mycoplasma penetrans / Q000737:chemistry*; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D012333:RNA, Messenger / Q000032:analysis
D001426:Bacterial Proteins; D008074:Lipoproteins; D008565:Membrane Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse