Opposing Roles of Blood-Borne Monocytes and Tissue-Resident Macrophages in Limbal Stem Cell Damage after Ocular Injury
Chengxin Zhou,
Fengyang Lei,
Mirja Mittermaier,
Bruce Ksander,
Reza Dana,
Claes H. Dohlman,
Demetrios G. Vavvas,
James Chodosh,
Eleftherios I. Paschalis
Affiliations
Chengxin Zhou
Department of Ophthalmology, Massachusetts Eye and Ear and Schepens Eye Research Institute, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA
Fengyang Lei
Department of Ophthalmology, Massachusetts Eye and Ear and Schepens Eye Research Institute, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA
Mirja Mittermaier
Department of Ophthalmology, Massachusetts Eye and Ear and Schepens Eye Research Institute, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA
Bruce Ksander
Department of Ophthalmology, Massachusetts Eye and Ear and Schepens Eye Research Institute, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA
Reza Dana
Department of Ophthalmology, Massachusetts Eye and Ear and Schepens Eye Research Institute, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA
Claes H. Dohlman
Department of Ophthalmology, Massachusetts Eye and Ear and Schepens Eye Research Institute, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA
Demetrios G. Vavvas
Retina Service, Department of Ophthalmology, Massachusetts Eye and Ear, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA
James Chodosh
Department of Ophthalmology, Massachusetts Eye and Ear and Schepens Eye Research Institute, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA
Eleftherios I. Paschalis
Department of Ophthalmology, Massachusetts Eye and Ear and Schepens Eye Research Institute, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA
Limbal stem cell (LSC) deficiency is a frequent and severe complication after chemical injury to the eye. Previous studies have assumed this is mediated directly by the caustic agent. Here we show that LSC damage occurs through immune cell mediators, even without direct injury to LSCs. In particular, pH elevation in the anterior chamber (AC) causes acute uveal stress, the release of inflammatory cytokines at the basal limbal tissue, and subsequent LSC damage and death. Peripheral C-C chemokine receptor type 2 positive/CX3C motif chemokine receptor 1 negative (CCR2+ CX3CR1−) monocytes are the key mediators of LSC damage through the upregulation of tumor necrosis factor-alpha (TNF-α) at the limbus. In contrast to peripherally derived monocytes, CX3CR1+ CCR2− tissue-resident macrophages have a protective role, and their depletion prior to injury exacerbates LSC loss and increases LSC vulnerability to TNF-α-mediated apoptosis independently of CCR2+ cell infiltration into the tissue. Consistently, repopulation of the tissue by new resident macrophages not only restores the protective M2-like phenotype of macrophages but also suppresses LSC loss after exposure to inflammatory signals. These findings may have clinical implications in patients with LSC loss after chemical burns or due to other inflammatory conditions.
