Mineralocorticoid receptor expression and the effects of the mineralocorticoid receptor antagonist spironolactone in a murine model of graft-versus-host disease

Purpose: The topical administration of spironolactone, a mineralocorticoid receptor antagonist (MRA) improves dry eye symptoms in patients with ocular graft-versus-host disease (GVHD); however, the detailed mechanism remains unclear. This study aimed to investigate the effects of spironolactone eyedrops on the ocular surface using a chronic GVHD (cGVHD) mouse model and to determine the expression of the mineralocorticoid receptor (MR).

Methods: A cGVHD mouse model was established by allogeneic bone marrow transplantation (BMT) from B10.D2 mice to BALB/c mice. Subsequently, cGVHD mice were treated with either 0.005 % spironolactone or vehicle eyedrops. The eyelids, cornea and conjunctiva of the recipients were analyzed at 4-week intervals post-BMT in both groups.

Results: Signs of ocular GVHD, such as corneal epithelial damage, depletion of meibomian glands, and inflammatory cell infiltration onto the ocular surface, were significantly decreased in cGVHD mice treated with spironolactone eyedrops. The expression of the MR NR3C2 in the corneal and conjunctival epithelia was significantly increased in cGVHD mice. HSP47⁺NR3C2⁺ MR-expressing fibroblasts, CD45⁺NR3C2⁺ MR-expressing leukocytes, and CD4⁺NR3C2⁺ MR-expressing T cells infiltrated the ocular surface tissue of cGVHD mice significantly more than that of syngeneic controls.

Conclusions: MR expression is increased in epithelial cells, fibroblasts, and T cells in a murine cGVHD model, whereas MRA and spironolactone eyedrops could attenuate the severity of ocular GVHD. These findings suggest that MR signaling partially contributes to the development of ocular GVHD in this mouse model.