PT  - JOURNAL ARTICLE
AU  - Eleftherios I Paschalis
AU  - Fengyang Lei
AU  - Chengxin Zhou
AU  - Vassiliki Kapoulea
AU  - Reza Dana
AU  - James Chodosh
AU  - Demetrios G. Vavvas
AU  - Claes H. Dohlman
TI  - Permanent neuroglial remodeling of the retina following infiltration of CSF1R-inhibition resistant peripheral monocytes
AID  - 10.1101/307900
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 307900
4099  - http://biorxiv.org/content/early/2018/05/14/307900.short
4100  - http://biorxiv.org/content/early/2018/05/14/307900.full
AB  - Previous studies have demonstrated that ocular injury can lead to prompt infiltration of bone marrow-derived peripheral monocytes into the retina. However, the ability of these cells to integrate into the tissue and become microglia has not been studied. Here we show that such peripheral monocytes not only infiltrate into the retina after ocular injury, but that they engraft permanently, migrate to the three distinct microglia strata, and adopt a microglia-like morphology. However, contrary to the original microglia, after injury the engrafted peripheral monocytes are resistant to depletion by colony stimulating factor 1 receptor (CSF1R) inhibitor and remain pro-inflammatory, expressing high levels of major histocompatibility complex II (MHC-II) for the long-term. In the absence of ocular injury, on the other hand, the peripheral monocytes that repopulate the retina after CSF1R inhibition remain sensitive to CSF1R inhibition and can be re-depleted. The observed permanent neuroglia remodeling after injury constitutes a major potential immunological change that may contribute to progressive retinal degeneration. These findings may be relevant also to other degenerative conditions of the retina and central nervous system.Significance statement: Ocular injury causes permanent neuroglia remodeling that promotes neuroinflammation.