The Generation of an ocular anti-inflammatory biotherapeutic to enhance wound healing.

Microbes exist at and colonize mucosal surfaces striking a balance with the host immune system, so that these microbes can thrive on host tissues without causing pathology. Because of this, mucosal barrier-colonizing bacteria can be leveraged to act as long-term delivery vehicles for naturally derived therapeutics. Here, we use a mouse model of corneal wound healing to show that the eye-colonizing bacterium, Corynebacterium mastitidis (C. mast) can be engineered to produce and secrete bioactive murine anti-inflammatory interleukin (mIL)-10. Specifically, we used transposon mutagenesis to identify a native C. mast-specific secretion signal that was used to direct C. mast to secrete mIL-10. Mini-transposons were generated to deliver secretion capable mIL-10 to the bacterial genome. After screening, two isolates were identified that can: 1) colonize the eye, 2) produce and secrete mIL-10, and 3) enhance wound healing in an IL-10-dependent manner. This proof of concept illustrates that eye-colonizing bacteria can be engineered to deliver therapeutics to the ocular surface for the alleviation of ocular surface disease(s).

UVB induced reactivation leads to HSV1 in the corneas of virtually all latently infected mice and requires STING to develop corneal disease.

Reactivation of latent herpes simplex type 1 results in virus returning to the cornea leading to recurrent herpetic stromal keratitis (rHSK). We compare two competing models to reactivate viruses from latency, UV-B irradiation and cyclophosphamide (CP). Results revealed that while both result in corneal recrudescence, only UV-B irradiation results in rHSK. To better understand the dynamics of reactivation, we analyzed corneas for both the presence of infectious viruses and the dynamics of exposure to multiple reactivations using UV-B. We noted that multiple reactivations result in progressively worse corneal disease. We also noted that expression of IFNα and STING, surragate markers for the presence of virus, are induced by the presence of reactivated virus. Studies to determine the importance of STING to the development of HSK revealed that in the absence of STING, mice do not develop significant HSK and the magnitude of the infiltrate of CD45+ cells in these corneas is significantly reduced. The resulting paucity of CD45+CD11b+GR-1+F4/80-neutrophils, and to a lesser extent CD45+CD11b+GR-1-F4/80+ macrophages in B6-STING KO mice following reactivation is likely the underlying cause for lack of rHSK as has been noted by ourselves and others. These results underscore the critical importance of STING's role in developing rHSK.