Corneal damage observed in a viral infection such as herpetic stromal keratitis is mainly caused by
proinflammatory molecules released by resident cells in the response to viral antigens. There are pattern
recognition receptors like MDA5, RIG-1, and TLR3, that recognize viral dsRNA and after activation, the
innate immune response is exacerbated inducing the synthesis and secretion of inflammatory cytokines
through NF-kB activation. Amniotic membrane (AM) has demonstrated to reduce inflammation by
several mechanisms, however the effect of AM on innate immune receptors such as MDA5, RIG-1, and
TLR3 has not been reported. In this study, we have determined that the presence of AM significantly
inhibited the synthesis and secretion of proinflammatory cytokines on human limbal myofibroblasts
(HLM) stimulated with poly I:C. Similarly, the presence of AM reduced the protein expression of MDA5,
RIG-1, and TLR3 on poly I:C stimulated HLM. Additionally, the presence of the AM significantly inhibited the NF-kB nuclear translocation when the HLM were poly I:C stimulated, and concomitantly, the AM was able to relocate cadherins affecting the myofibroblastic cellular morphology. These results suggest that AM generates an anti-inflammatory microenvironment, and specific inhibition of NFkB nuclear translocation on infected corneal tissue would reduce the inflammation undesirable effects, explaining in part the beneficial usefulness of transplanting AM on herpetic stromal keratitis.
