LIN28‐ let‐7 axis regulates genes in immortalized human trophoblast cells by targeting the ARID3B‐complex

Abstract

Abnormal placental development is one of the main etiological factors for intrauterine growth restriction (IUGR). Here, we show that LIN28A and LIN28B are significantly lower and lethal‐7 (let‐7) microRNAs (miRNAs) significantly higher in term human IUGR vs. normal placentas. We hypothesize that let‐7 miRNAs regulate genes with known importance for human placental development [high‐mobility group AT‐hook 1 (HMGA1), transcriptional regulator Myc‐like (c‐myc), vascular endothelial growth factor A (VEGF‐A), and Wnt family member 1 (WNT1)] by targeting the AT‐rich interacting domain (ARID)‐3B complex. ACH‐3P cells with LIN28A and LIN28B knockout (DKOs) significantly increased let‐7 miRNAs, leading to significantly decreased ARID3A, ARID3B, and lysine demethylase 4C (KDM4C). Similarly, Sw.71 cells overexpressing LIN28A and LIN28B (DKIs) significantly decreased let‐7 miRNAs, leading to significantly increased ARID3A, ARID3B, and KDM4C. In ACH‐3P cells, ARID3A, ARID3B, and KDM4C make a triprotein complex [triprotein complex comprising ARID3A, ARID3B, and KDM4C (ARID3B‐complex)] that binds the promoter regions of HMGA1, c‐MYC, VEGF‐A, and WNT1. ARID3B knockout in ACH‐3P cells disrupted the ARID3B‐complex, leading to a significant decrease in HMGA1, c‐MYC, VEGF‐A, and WNT1. DKOs had a significant reduction, whereas DKIs had a significant increase in HMGA1, c‐MYC, VEGF‐A, and WNT1, potentially due to regulation by the ARID3B‐complex. This is the first study showing regulation of let‐7 targets in immortalized human trophoblast cells by the ARID3B‐complex.—Ali, A., Anthony, R. V., Bouma, G. J., Winger, Q. A. LIN28‐let‐7 axis regulates genes in immortalized human trophoblast cells by targeting the ARID3B‐complex. FASEB J. 33, 12348–12363 (2019). http://www.fasebj.org

Trophectoderm-Specific Knockdown of LIN28 Decreases Expression of Genes Necessary for Cell Proliferation and Reduces Elongation of Sheep Conceptus

“…We recently showed that term human placentas from IUGR pregnancies had reduced LIN28A and LIN28B and high let-7 miRNAs compared to term human placentas from control pregnancies [18]. We further demonstrated that LIN28B is localized to cytotrophoblast cells in human placenta, and knockout of LIN28 in immortalized first trimester human trophoblast (ACH-3P) cells leads to an increase in let-7 miRNAs, reduced expression of proliferation-associated genes, and reduced cell proliferation [18][19][20].…”

“…Trophoblast proliferation and differentiation is an intensively regulated process, and the role of several genes in placental development has been studied using various in vivo and in vitro models [16][17][18][19][20]. The pluripotency factor LIN28 is a highly conserved RNA binding protein which is expressed in placenta and has two paralogs, LIN28A and LIN28B [21,22].…”

“…LIN28 is low and let-7 miRNAs are high in differentiated cells and adult tissues, hence let-7 miRNAs are considered markers of cell differentiation [31][32][33]. Let-7 miRNAs reduce the expression of different proliferation factors either by directly targeting their mRNA or through chromatin-dependent pathways by targeting the ARID3B-complex, which is comprised of AT-Rich Interaction Domain 3A (ARID3A), AT-Rich Interaction Domain 3B (ARID3B) and lysine demethylase 4C (KDM4C) [18,34]. We recently showed that term human placentas from IUGR pregnancies had reduced LIN28A and LIN28B and high let-7 miRNAs compared to term human placentas from control pregnancies [18].…”

“…Let-7 miRNAs reduce the expression of different proliferation factors either by directly targeting their mRNA or through chromatin-dependent pathways by targeting the ARID3B-complex, which is comprised of AT-Rich Interaction Domain 3A (ARID3A), AT-Rich Interaction Domain 3B (ARID3B) and lysine demethylase 4C (KDM4C) [18,34]. We recently showed that term human placentas from IUGR pregnancies had reduced LIN28A and LIN28B and high let-7 miRNAs compared to term human placentas from control pregnancies [18]. We further demonstrated that LIN28B is localized to cytotrophoblast cells in human placenta, and knockout of LIN28 in immortalized first trimester human trophoblast (ACH-3P) cells leads to an increase in let-7 miRNAs, reduced expression of proliferation-associated genes, and reduced cell proliferation [18][19][20].…”

“…Insulin like growth factor 2 mRNA binding proteins (IGF2BP1, IGF2BP2, IGF2BP3), high mobility group AT-hook 1 (HMGA1), ARID3B, and MYC protooncogene (c-MYC) are all let-7 miRNA targets with known roles in cell proliferation [18,[35][36][37][38][39][40][41]. IGF2BPs are highly conserved RNA binding oncofetal proteins with three paralogs, IGF2BP1, IGF2BP2, and IGF2BP3 [42].…”