Transcription Factor EB (TFEB) Expression and Localization in the Third-Trimester Placenta

Transcription factor EB (TFEB) is expressed at high levels in the trophoblast cells of the placenta, where it plays a critical role in regulating normal vascularization. Preeclampsia (PE) is a severe complication of pregnancy with a high incidence of maternal and fetal morbidity and mortality. Gestational diabetes (GD) is a metabolic disease that can affect placental villous maturation and villous vascularity. We analyzed the expression of three different antibodies: TFEB from Invitrogen (TFEB-INV), which detects endogenous levels of TFEB only when phosphorylated at Ser211; TFEB from Bethyl Labs (TFEB-B), which recognizes and binds E-box sequences; and TFEB from Santa Cruz (C-6) (TFEB-SC), which is specifically used for epitope mapping between 440 and 470. We evaluated the presence/absence of TFEB in six placental districts: syncytiotrophoblast (STB), cytotrophoblast (CTB), extravillous trophoblast (EVT), syncytial knots, stem villi vessels, and villous capillaries. TFEB-B was significantly expressed in the stem villi vessels, STB, and villi vessels of GD cases. The lack of TFEB expression in late-onset PE appears to corroborate the role of TFEB in vascular remodeling during placental development. The positive results in STB and vessels in GD cases, regardless of the histological diagnosis, may suggest that the expression of TFEB mitigates hypoxic injury via the Akt/mTOR pathway.