Non-cell-adhesive hydrogel promotes formation of human blastoids from primed human pluripotent stem cells

Abstract

Artificial human blastoids investigate fundamentals of early embryo development using in vitro models and study the pregnancy failures and birth deficiencies, previously hindered by the need for human embryos. Recent methods on generating blastoids used human naive pluripotent stem cells, which are prone to genomic instability during in vitro culturing. We introduce a simple, robust, and scalable method for generating human blastoids from more stable, human-primed, embryonic stem cells (hESC). Using a non-cell-adhesive hydrogel, hESC aggregates received the chemophysical cellular environment and formed an asymmetric blastoid structure with a cellular distribution similar to that of a human blastocyst. The obtained blastoids also demonstrated the capability of implantation in vitro. This model will allow studies on the underlying mechanisms of human pre- and post-implantation processes, leading to assisted reproductive technology.

In Vitro Embryogenesis and Gastrulation Using Stem Cells in Mice and Humans

“…However, the number of TE- and PrE-like cells in these blastoids was relatively low compared to that of natural blastocysts. Additionally, the blastoid formation efficiency of this study remained low compared to other methods using naïve hPSCs [ 152 ].…”

“…Imamura et al noted that human blastocysts are surrounded by a glycoprotein layer—zona pellucida (ZP)—and that primed hPSCs can be converted to a naïve pluripotent state through 3D culture in AggreWell plates [ 164 ]. In their study, aggregates of primed hPSCs were transferred to ultralow attachment culture dishes in hydrogel (HG) medium, which provides an environment for the ZP layer and converts to a naïve hPSC state with the aim of inducing blastoid formation [ 152 ]. Approximately 14.1% of the structures formed exhibited features similar to E5–7 blastocysts.…”

“…In summary, human blastoids can be generated through various methods, including the 3D culturing of naïve hPSCs, conversion of primed and naïve hPSCs, and somatic cell reprogramming [ 24 , 25 , 26 , 27 , 28 ]. Human blastoids exhibit many features of natural blastocysts, including morphological and architectural similarities, the ability to undergo in vitro peri-implantation development, and the capability to derive three stem cell types (ESCs, XENCs, and TSCs) [ 27 , 150 , 151 , 152 ]. This suggests that human blastoids are useful in in vitro models designed for studying pre- and peri-implantation development in humans.…”

“…The resulting human blastoids are similar to natural blastocysts and exhibit the developmental potential to form structures resembling amniotic cavities and yolk sacs. hEPSCs: human expanded potential stem cells; hPSCs: human pluripotent stem cells; TSCs: trophoblast stem cells; EPI: epiblast; TE: trophectoderm; PrE: primitive endoderm; OKSM: Oct4, Klf4, Sox2, and c-Myc; iBlastoid: induced blastoid [ 24 , 25 , 26 , 27 , 28 , 150 , 151 , 152 ].…”

<em>In vitro</em> Embryogenesis and Gastrulation using Stem Cells

“…Imamura et al noted that human blastocysts are surrounded by a glycoprotein layerzona pellucida (ZP)-and that primed hPSCs can be converted to a naïve pluripotent state through 3D culture in AggreWell plates [164]. In their study, aggregates of primed hPSCs were transferred to ultralow attachment culture dishes in hydrogel (HG) medium, which provides an environment for the ZP layer and converts to a naïve hPSC state with the aim of inducing blastoid formation [152]. Approximately 14.1% of the structures formed exhibited features similar to E5-7 blastocysts.…”