Aromatase Controls Sjögren Syndrome–Like Lesions through Monocyte Chemotactic Protein-1 in Target Organ and Adipose Tissue–Associated Macrophages

Several autoimmune diseases are known to develop in postmenopausal women. However, the mechanism by which estrogen deficiency influences autoimmunity is unknown. Aromatase is a converting enzyme from androgens to estrogens. In the present study, we used female aromatase gene knockout (ArKO) mice as a model of estrogen deficiency to investigate the molecular mechanism that underlies the onset and development of autoimmunity. Histological analyses showed that inflammatory lesions in the lacrimal and salivary glands of ArKO mice increased with age. Adoptive transfer of spleen cells or bone marrow cells from ArKO mice into recombination activating gene 2 knockout mice failed to induce the autoimmune lesions. Expression of mRNA encoding proinflammatory cytokines and monocyte chemotactic protein-1 (MCP-1) increased in white adipose tissue (WAT) of ArKO mice and was significantly higher than that in wild-type mice. Moreover, an increased number of inflammatory M-1 macrophage was observed in WAT of ArKO mice. A significantly increased MCP-1 mRNA expression of the salivary gland tissue in ArKO was found together with adiposity. Furthermore, the autoimmune lesions in a murine model of Sjögren’s syndrome (SS) were exacerbated by administration of an aromatase inhibitor. These results suggest that aromatase may play in a key role in the pathogenesis of SS-like lesions by controlling the target organ and adipose tissue-associated macrophage.

© 2014. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/