Potential new mechanisms of placental damage in celiac disease: anti-transglutaminase antibodies impair human endometrial angiogenesis

Celiac disease (CD) is an autoimmune enteropathy triggered by gluten ingestion and characterized by circulating anti-transglutaminase type 2 (anti-TG2) autoantibodies. An epidemiological link between maternal CD and increased risk of pregnancy failure has been established; however, the mechanism underlying this association is still poorly understood. Because proper endometrial angiogenesis and decidualization are prerequisites for placental development, we investigated the effect of anti-TG2 antibodies on the process of endometrial angiogenesis. Binding of anti-TG2 antibodies to human endometrial endothelial cells (HEECs) was evaluated by ELISA. Angiogenesis was studied in vitro on HEECs and in vivo in a murine model. In particular, we investigated the effect of anti-TG2 antibodies on HEEC matrix metalloprotease-2 (MMP-2) activity by gelatin zymography, cytoskeletal organization and membrane properties by confocal microscopy, and activation of extracellular signal-regulated kinases (ERKs) and focal adhesion kinase (FAK) by Western blot analysis. Anti-TG2 antibodies bound to HEECs and decreased newly formed vessels both in vitro and in vivo. Anti-TG2 antibodies impaired angiogenesis by inhibiting the activation of MMP-2, disarranging cytoskeleton fibers, changing the physical and mechanical properties of cell membranes, and inhibiting the intracellular phosphorylation of FAK and ERK. Anti-TG2 antibodies inhibit endometrial angiogenesis affecting the TG2-dependent migration of HEECs and extracellular matrix degradation, which are necessary to form new vessels. Our results identify pathogenic mechanisms of placental damage in CD.