TLRs and NODs mRNA expression pattern in healthy mouse eye

Aims: To look for TLR and NOD mRNA expression in the healthy eye and in other immune privileged and non-immune privileged mouse organs. Methods: Semiquantitative RT-PCR was performed to look for TLR1-9 and NOD1 and NOD2 mRNA expressions in the whole eye, in the anterior (AP) and posterior ( PP) portions of the eye, in corneal fibroblasts (CF) and in ovary, brain, testis, heart, lung, and spleen. Results: All the TLR mRNAs were expressed in the whole eye of Balb/c mice. NIH and C57BL/6 did not express TLR9 and TLR8, respectively. NIH expressed higher levels of TLR1, 2, 3, and 6 than the other strains. C57BL/6 expressed the lowest levels of all TLRs. TLR9, 5, and 4 were the less expressed in all strains. All TLRs were expressed in Balb/c PP and TLR1 was not expressed in AP. In NIH and Balb/c CF the majority of TLRs were overexpressed with LPS. In testis, expression of most TLRs was absent. Non-immune privileged organs expressed most of the TLRs. All the organs expressed NOD1 and NOD2. In PP NOD2 was not expressed. Conclusion: TLRs and NODs are expressed in the eye, and could have an important role in the innate immunity.