Lipid‐associated membrane proteins of Mycoplasma fermentans and M. penetrans activate human immunodeficiency virus long‐terminal repeats through Toll‐like receptors

Abstract

SUMMARYMycoplasmas are known to enhance human immunodeficiency virus (HIV) replication, and mycoplasma-derived lipid extracts have been reported to activate nuclear factor-jB (NF-jB) through Toll-like receptors (TLRs). In this study, we examined the involvement of TLRs in the activation of HIV long-terminal repeats (LTR) by mycoplasma and their active components responsible for the TLR activation. Lipid-associated membrane proteins (LAMPs) from two species of mycoplasma (Mycoplasma fermentans and M. penetrans) that are associated with acquired immune-deficiency syndrome (AIDS), were found to activate HIV LTRs in a human monocytic cell line, THP-1. NF-jB deletion from the LTR resulted in inhibition of the activation. The LTR activation by M. fermentans LAMPs was inhibited by a dominant negative (DN) construct of TLR1 and TLR6, whereas HIV LTR activation by M. penetrans LAMPs was inhibited by DN TLR1, but not by DN TLR6. These results indicate that the activation of HIV LTRs by M. fermentans and M. penetrans LAMPs is dependent on NF-jB, and that the activation of HIV LTR by M. fermentans LAMPs is mediated through TLR1, TLR2 and TLR6. In contrast, the LTR activation by M. penetrans LAMPs is carried out through TLR1 and TLR2, but not TLR6. Subsequently, the active component of M. penetrans and M. fermentans LAMPs was purified by reverse-phase high-performance liquid chromatography (HPLC). Interestingly, the purified lipoprotein of M. penetrans LAMPs (LPMp) was able to activate NF-jB through TLR1 and TLR2. On the other hand, the activation of NF-jB by purified lipoprotein of M. fermentans LAMPs (LPMf) was mediated through TLR2 and TLR6, but not TLR1.

A Triacylated Lipoprotein fromMycoplasma genitaliumActivates NF-κB through Toll-Like Receptor 1 (TLR1) and TLR2

“…Furthermore, the resistance to Edman degradation of proteins from M. mycoides also indicates the presence of N acylation (5). We previously showed that lipoproteins from M. fermentans enhance human immunodeficiency virus replication through TLR2 and TLR6 but lipoproteins from M. penetrans facilitate human immunodeficiency virus replication through TLR1, TLR2, and TLR6 (42). We also reported that the lipoproteins isolated from M. pneu- 293T cells were transfected with 0.2 g/ml of pFLAG-dTLR6 or pFLAG-dTLR1, 0.01 g/ml of pFLAG-TLR2, 0.01 g/ml of pNFkB-luc, and 0.01 g/ml of pRL-TK.…”

Nuclear Receptor Signaling Inhibits HIV-1 Replication in Macrophages through Multipletrans-Repression Mechanisms

“…The data are the means (ϮSD) from four independent experiments using different donors. 134,139,161). Therefore, the use of the synthetic TLR2 ligand PAM3CSK4 recapitulates the contribution of other STI cofactors on HIV-1 replication in macrophages.…”

Mycoplasma lipoproteins and Toll-like receptors

“…In contrast, TLR1-deficient cells show a normal response to mycoplasma-derived diacylated lipopeptides, but an impaired response to triacylated lipopeptides. Shimizu et al(2004) found that the purified lipoprotein of M. penetrans LAMPs was able to activate NF-κB through TLR1 and TLR2. On the other hand, the activation of NF-κB by the purified lipoproteins of M. fermentans LAMPs was mediated through TLR2 and TLR6, but not TLR1.…”

“…This suggests that the active components are attributed to lipid moieties, although the moieties of proteins might have other functions (Shimizu et al, 2004). The acylated proteins of mycoplasmas are abundant cell-surface antigens, which are recognized by extra-cellular domains of TLRs.…”