Cardiac Development in the Presence of Cadmium: An in Vitro Study Using Human Embryonic Stem Cells and Cardiac Organoids

Abstract

Background: Exposure to cadmium (Cd) is associated with cardiovascular diseases. Maternal Cd exposure is a significant risk factor for congenital heart disease. However, mechanisms of Cd on developmental cardiotoxicity are not well defined. Objectives: We evaluated the effects of Cd on the different stages (mesoderm, cardiac induction, cardiac function) of cardiac development using an early embryo development in vitro model and two- or three-dimensional (2- or 3D) cardiomyocyte and cardiac organoid formation models mimicking early cardiac development. Methods: Embryonic stem cells (ESCs) form 3D aggregates, called embryoid bodies, that recapitulate events involved with early embryogenesis (e.g., germ layer formation). This model was used for early germ layer formation and signaling pathway identification. The 2D cardiomyocyte differentiation from the human ESCs model was used to explore the effects of Cd exposure on cardiomyocyte formation and to model mesoderm differentiation and cardiac induction, allowing us to explore different developmental windows of Cd toxicity. The 3D cardiac organoid model was used in evaluating the effects of Cd exposure on contractility and cardiac development. Results: Cd ( ; ) lowered the differentiation of embryoid bodies to mesoderm via suppression of –signaling pathways. During early mesoderm induction, the mesoderm-associated transcription factors MESP1 and EOMES showed a transient up-regulation, which decreased later in the cardiac induction stage. Cd ( ) lowered mesoderm formation and cardiac induction through suppression of the transcription factors and mesoderm marker genes HAND1 , SNAI2 , HOPX , and the cardiac-specific genes NKX2 -5, GATA4 , troponin T, and . In addition, Cd-induced histone modifications for both gene activation (H3K4me3) and repression (H3K27me3), which play vital roles in regulating mesoderm commitment markers. The effects of Cd inhibition on cardiomyocyte differentiation were confirmed in 3D cardiac organoids. Discussion: In conclusion, using a human ESC-derived 2D/3D in vitro differentiation model system and cardiac organoids, we demonstrated that low-dose Cd suppressed mesoderm formation through mesoderm gene histone modification, thus inhibiting cardiomyocyte differentiation and cardiac induction. The studies provide valuable insights into cellular events and molecular mechanisms associated with Cd-induced congenital heart disease. https://doi.org/10.1289/EHP11208

Investigating the applicability domain of the hiPSC-based PluriLum assay: an embryotoxicity assessment of chemicals and drugs

“…On the other hand, Zhang et al demonstrated in a basic research study that molecular mechanisms are highly comparable between 2D and 3D (Zhang et al 2015 ). In a work of Wu et al, exposure to cadmium was shown to negatively affect cardiac maturation in both 2D and 3D models, though an effect at lower exposure levels was observed in the first model (Wu et al 2022 ). This was attributed to a lower contact of the 3D organoids to the chemical when compared to the exposed monolayer, which also advocates for a more in vivo like effect of 3D organoids, though sacrificing the sensitivity of the assay.…”

“…Including the PluriLum assay, there are five human stem cell-based reporter cell systems for assessment of toxic effects reported. Three reporter systems are related to expression of NKX2.5 (Fu et al 2019 ; Lauschke et al 2021b ; Wu et al 2022 ), one with TNNT2 (Cao et al 2019 ) and one with MESP1 expression (Pan et al 2018 ), and all of them, with the exception of the one developed by our group (Lauschke et al 2021b ), are based on hESCs.…”

The new era of cardiovascular research: revolutionizing cardiovascular research with 3D models in a dish

“…This innovative approach minimized cardiotoxicity in both hiPSC-CMs and cardiac spheroids while preserving doxorubicin’s anti-cancer effect. In addition to investigating the cardiotoxic effects induced by anti-cancer drugs, cardiac organoids have also recently become a vital tool in exploring the cardiotoxicity arising from environmental pollutants [ 127 ], [ 128 ], [ 129 ]. Following exposure to polystyrene microplastics with a dose equivalent to the exposure level in humans, cardiac organoids exhibited increased oxidative stress, inflammatory response, apoptosis, and collagen accumulation which were consistent with an in vivo study [ 128 ].…”

Human-Organoid-Based In Vitro Modeling for Environmental Toxicology

“…Similarly, an elegant study revealed that exposure to the transition metal cadmium induced impaired neurogenesis, disruptions in neuronal maturation, and regionalization, as examined in hiPSCs-derived brain organoids incorporated on an array chip with octagon-shaped micropillars . Using a hESC-derived 2D/3D in vitro differentiation model system and cardiac organoids, low-dose cadmium exposure was evidenced to suppress mesoderm formation and consequently inhibit cardiomyocyte differentiation and cardiac induction . Collectively, a handful of studies have demonstrated that human organoid in vitro platforms serve as crucial tools for the safety and toxicity assessment of environmental insults, including emerging environmental pollutants.…”