Table 2.
Human TLRs and their ligands
| TLR | Localization | Canonical ligand | Abnormalities in MDS | References |
|---|---|---|---|---|
| TLR1 | Plasma membrane | Triacyl lipoproteins | Overexpressed | Wei et al.51 |
| TLR2 | Plasma membrane | Lipoproteins (dimerizes with TLR1 or TLR6) | Overexpressed, higher in low-risk MDS, mutated | Kuninaka et al.,50 Wei et al.51 |
| TLR3 | Endolysosomes | dsRNA | Not reported | |
| TLR4 | Plasma membrane | LPS | Overexpressed, correlated with apoptosis | Maratheftis et al.,49 Kuninaka et al.50 |
| TLR5 | Plasma membrane | Flagellin | Not reported | |
| TLR6 | Plasma membrane | Diacyl lipoproteins | Overexpressed, higher in high-risk MDS | Wei et al.51 |
| TLR7 | Endolysosomes | ssRNA and small purine analogs | Overexpressed | Ganan-Gomez et al.120 |
| TLR8 | Endolysosomes | ssRNA | Not reported | |
| TLR9 | Endolysosomes | CpG-DNA | Overexpressed, correlated with TNF-α expression, decreased with progression | Kuninaka et al.50 |
| TLR11 | Plasma membrane | Unknown | Not reported |
Abbreviations: LPS, lipopolysaccharide; MDS, myelodysplastic syndrome; TLR, Toll-like receptor.