Polyoxyethylene tallow amine and glyphosate exert different developmental toxicities on human pluripotent stem cells-derived heart organoid model.

The early stage of heart development is highly susceptible to various environmental factors. While the use of animal models has aided in identifying numerous environmental risk factors, the variability between species and the low throughput limit their translational potential. Recently, a type of self-assembling cardiac structures, known as human heart organoids (hHOs), exhibits a remarkable biological consistency with human heart. However, the feasibility of hHOs for assessing cardiac developmental risk factors remains unexplored. Here, we focused on the cardiac developmental effects of core components of Glyphosate-based herbicides (GBHs), the most widely used herbicides, to evaluate the reliability of hHOs for the prediction of possible cardiogenesis toxicity. GBHs have been proven toxic to cardiac development based on multiple animal models, with the mechanism remaining unknown. We found that polyoxyethylene tallow amine (POEA), the most common surfactant in GBHs formulations, played a dominant role in GBHs' heart developmental toxicity. Though there were a few differences in transcriptive features, hHOs exposed to sole POEA and combined POEA and Glyphosate would suffer from both disruption of heart contraction and disturbance of commitment in cardiomyocyte isoforms. By contrast, Glyphosate only caused mild epicardial hyperplasia. This study not only sheds light on the toxic mechanism of GBHs, but also serves as a methodological demonstration, showcasing its effectiveness in recognizing and evaluating environmental risk factors, and deciphering toxic mechanisms.

VGLL4 promotes vascular endothelium specification via TEAD1 in the vascular organoids and human pluripotent stem cells-derived endothelium model.

BACKGROUND: We have shown that Hippo-YAP signaling pathway plays an important role in endothelial cell differentiation. Vestigial-like family member 4 (VGLL4) has been identified as a YAP inhibitor. However, the exact function of VGLL4 in vascular endothelial cell development remains unclear. In this study, we investigated the role of VGLL4, in human endothelial lineage specification both in 3D vascular organoid and 2D endothelial cell differentiation. METHODS AND RESULTS: In this study, we found that VGLL4 was increased during 3D vascular organoids generation and directed differentiation of human embryonic stem cells H1 towards the endothelial lineage. Using inducible ectopic expression of VGLL4 based on the piggyBac system, we proved that overexpression of VGLL4 in H1 promoted vascular organoids generation and endothelial cells differentiation. In contrast, VGLL4 knockdown (heterozygous knockout) of H1 exhibited inhibitory effects. Using bioinformatics analysis and protein immunoprecipitation, we further found that VGLL4 binds to TEAD1 and facilitates the expression of endothelial master transcription factors, including FLI1, to promote endothelial lineage specification. Moreover, TEAD1 overexpression rescued VGLL4 knockdown-mediated negative effects. CONCLUSIONS: In summary, VGLL4 promotes EC lineage specification both in 3D vascular organoid and 2D EC differentiation from pluripotent stem cell, VGLL4 interacts with TEAD1 and facilitates EC key transcription factor, including FLI1, to enhance EC lineage specification.

VGLL4-TEAD1 promotes vascular smooth muscle cell differentiation from human pluripotent stem cells via TET2.

The Hippo signaling pathway plays a critical role in cardiovascular development and stem cell differentiation. Using microarray profiling, we found that the Hippo pathway components vestigial-like family member 4 (VGLL4) and TEA domain transcription factor 1 (TEAD1) were upregulated during vascular smooth muscle cell (VSMC) differentiation from H1 ESCs (H1 embryonic stem cells). To further explore the role and molecular mechanisms of VGLL4 in regulating VSMC differentiation, we generated a VGLL4-knockdown H1 ESC line (heterozygous knockout) using the CRISPR/Cas9 system and found that VGLL4 knockdown inhibited VSMC specification. In contrast, overexpression of VGLL4 using the PiggyBac transposon system facilitated VSMC differentiation. We confirmed that this effect was mediated via TEAD1 and VGLL4 interaction. In addition, bioinformatics analysis revealed that Ten-eleven-translocation 2 (TET2), a DNA dioxygenase, is a target of TEAD1, and a luciferase assay further verified that TET2 is the target of the VGLL4-TEAD1 complex. Indeed, TET2 overexpression promoted VSMC marker gene expression and countered the VGLL4 knockdown-mediated inhibitory effects on VSMC differentiation. In summary, we revealed a novel role of VGLL4 in promoting VSMC differentiation from hESCs and identified TET2 as a new target of the VGLL4-TEAD1 complex, which may demethylate VSMC marker genes and facilitate VSMC differentiation. This study provides new insights into the VGLL4-TEAD1-TET2 axis in VSMC differentiation and vascular development.

YAP inhibition promotes endothelial cell differentiation from pluripotent stem cell through EC master transcription factor FLI1.

Endothelial cells (ECs) derived from pluripotent stem cells (PSCs) provide great resource for vascular disease modeling and cell-based regeneration therapy. However, the molecular mechanisms of EC differentiation are not completely understood. In this study, we checked transcriptional profile by microarray and found Hippo pathway is changed and the activity of YAP decreased during mesoderm-mediated EC differentiation from human embryonic stem cells (hESCs). Knockdown of YAP in hESCs promoted both mesoderm and EC differentiation indicating by mesodermal- or EC-specific marker gene expression increased both in mRNA and protein level. In contrast, overexpression of YAP inhibited mesoderm and EC differentiation. Microarray data showed that several key transcription factors of EC differentiation, such as FLI1, ERG, SOX17 are upregulated. Interestingly, knockdown YAP enhanced the expression of these master transcription factors. Bioinformation analysis revealed that TEAD, a YAP binds transcription factors, might regulate the expression of EC master TFs, including FLI1. Luciferase assay confirmed that YAP binds to TEAD1, which would inhibit FLI1 expression. Finally, FLI1 overexpression rescued the effects of YAP overexpression-mediated inhibition of EC differentiation. In conclusion, we revealed the inhibitory effects of YAP on EC differentiation from PSCs, and YAP inhibition might promote expression of master TFs FLI1 for EC commitment through interacting with TEAD1, which might provide an idea for EC differentiation and vascular regeneration via manipulating YAP signaling.

Generation of human embryonic stem cell lines (WAe001-A-67,WAe001-A-68) with TEAD1 and TEAD4 expression by the PiggyBac transposon system.

Transcription factors TEAD1 and TEAD4 play an important role in development, differentiation, cell growth and proliferation. To further understand the exact role of TEAD1 and TEAD4 in these processes. We generated TEAD1 and TEAD4 doxycycline-inducible expression human embryonic stem cell lines (WAe001-A-67 and WAe001-A-68) by PiggyBac transposon system. These cell lines retained normal morphology and karyotype, normal expression of pluripotent markers, and differentiation potential. These cell lines can be used to verify whether the TEAD1 and TEAD4 play a role in stem cell and cell lineage differentiation.

Establishment and characterization of human induced pluripotent stem cell line (WMUi020-A) from a patient with bicuspid aortic valve aortopathy.

A human induced pluripotent stem cell (hiPSC) line (WMUi020-A) was generated from the aortic smooth muscle cells of a 56-year-old donor with bicuspid aortic valve and ascending aortic aneurysm. Episomal vector-mediated Non-integration iPSC reprogramming was used for this iPSC line generation. The established iPSC line highly expressed pluripotency markers with three germ-layer differentiation potential in vitro, as well as a normal karyotype. We further found that this iPSC line has a potential mutation of ROBO4 (c.161 T>C, p.Q54R), which may be useful for the disease modeling of bicuspid aortic valve aortopathy.

Generation of human induced pluripotent stem cell line (WMUi001-A) from a patient with aortic dissection.

A human induced pluripotent stem cell (hiPSC) line (WMUi001-A) was generated from the aortic tissue of a 47-year-old donor with aortic dissection and normal blood pressure. Integration-free episomal vector-mediated reprogramming was used for the generation of this iPSC line. The established iPSC line was found to express pluripotency markers, exhibit a differentiation potential in vitro, as well as display a normal karyotype. We further identified that this iPSC line contained a mutation in collagen type IV (COL4A2, R131M), which may serve as a useful tool for the disease modeling of aortic dissection.

Generation of a human embryonic stem cell (WAe001-A-47) with hVGLL4 doxycyclin-inducible expression by the PiggyBac transposon system.

VGLL4 is a new component of the Hippo pathway and bind TEADs to compete with YAP, so as to inhibit tumor progression, but its role in stem cell and organ regeneration remains unclear. Using the PiggyBac transposon system, we generated a VGLL4 doxycycline-inducible expression human embryonic stem cell line (WAe001-A-47). The established hESC line retains its normal morphology and pluripotency markers with in vitro differentiation potential, as well as a normal karyotype.

Epigallocatechin-3-gallate (EGCG) inhibits aggregation of pulmonary fibrosis associated mutant surfactant protein A2 via a proteasomal degradation pathway.

BACKGROUND/AIMS: Epigallocatechin-3-gallate (EGCG), a major catechin found in green tea, plays an important anti-tumor role and is involved in various other biological processes, such as, neuroprotection by prevention of aggregation of misfolded proteins generated because of genetic defects. Surfactant protein A2 mutations (G231V and F198S) have been identified to be associated with pulmonary fibrosis and lung cancer, and these mutations cause protein aggregation, instability as well as secretion deficiency. The present study focused on investigating the inhibitory effects of EGCG on aggregation of mutant SP-A2 and elucidating the potential mechanisms underlying this action. METHODS: Wild-type and mutant SP-A2 were transiently expressed in CHO-K1 cells. The aggregated and soluble proteins were separated into NP-40-insoluble and NP-40-soluble fractions. Protein stability was validated by chymotrypsin limited proteolysis assay. Western blot and RT-PCR were used to determine the protein and mRNA expression level, respectively. RESULTS: Mutant SP-A2 alone or wild-type SP-A2 co-expressed with G231V formed NP-40-insoluble aggregates in CHO-K1 cells. EGCG significantly suppressed this aggregation and alleviated mutant SP-A2 accumulation in the ER. When combined with 4-PBA, EGCG treatment completely blocked mutant SP-A2 aggregate formation. Though secretion of mutant protein was not affected, EGCG facilitated protein instability in both wild-type and mutant protein. Importantly, MG132, a proteasome inhibitor, reversed EGCG-induced aggregate reduction. CONCLUSIONS: EGCG inhibits aggregation of misfolded SP-A2 via induction of protein instability and activation of proteasomal pathway for aggregate degradation.