Haploid-genetic screening of trophectoderm specification identifies Dyrk1a as a repressor of totipotent-like status

Predicting tumour resistance to paclitaxel and carboplatin utilising genome-wide screening in haploid human embryonic stem cells

Taxanes and platinum molecules, specifically paclitaxel and carboplatin, are widely used anticancer drugs that induce cell death and serve as first-line chemotherapy for various cancer types. Despite the efficient effect of both drugs on cancer cell proliferation, many tumours have innate resistance against paclitaxel and carboplatin, which leads to inefficient treatment and poor survival rates. Haploid human embryonic stem cells (hESCs) are a novel and robust platform for genetic screening. To gain a comprehensive view of genes that affect or regulate paclitaxel and carboplatin resistance, genome-wide loss-of-function screens in haploid hESCs were performed. Both paclitaxel and carboplatin screens have yielded selected plausible gene lists and pathways relevant to resistance prediction. The effects of mutations in selected genes on the resistance to the drugs were demonstrated. Based on the results, an algorithm that can predict resistance to paclitaxel or carboplatin was developed. Applying the algorithm to the DNA mutation profile of patients' tumours enabled the separation of sensitive versus resistant patients, thus, providing a prediction tool. As the anticancer drugs arsenal can offer alternatives in case of resistance to either paclitaxel or carboplatin, an early prediction can provide a significant advantage and should improve treatment. The algorithm assists this unmet need and helps predict whether a patient will respond to the treatment and may have an immediate clinically actionable application.

Capture of Totipotency in Mouse Embryonic Stem Cells in the Absence of Pdzk1

Totipotent cells can differentiate into three lineages: the epiblast, primitive endoderm, and trophectoderm. Naturally, only early fertilized embryos possess totipotency, and they lose this ability as they develop. The expansion of stem cell differentiation potential has been a hot topic in developmental biology for years, particularly with respect to the generation totipotent-like stem cells. Here, the study describes the establishment of totipotency in embryonic stem cells (ESCs) via the deletion of a single gene, Pdzk1. Pdzk1-knockout (KO) ESCs substantially contribute to the fetus, placenta, and yolk sac in chimera assays but can also self-organize to form standard blastocyst-like structures containing the three lineages efficiently; thus, they exhibit full developmental potential as early blastomeres. Single-cell transcriptome and bulk RNA-seq comprehensive analyses revealed that Pdzk1-KO activates several lineage inducers (C1qa, C1qb, Fgf5, and Cdx2) to break down barriers between embryonic and extraembryonic tissues, making these lineages switch smoothly and resulting in a totipotent-like state. This versatile and scalable system provides a robust experimental model for differentiation potency and cell fate studies.

Protocol for the derivation and culture of murine trophoblast organoids for CRISPR-Cas9 screening

Murine trophoblast organoids present a more balanced array of trophoblast subtypes, rendering them a suitable platform for CRISPR-Cas9-based screening. Here, we present a protocol for the derivation and culture of murine trophoblast organoids from trophoblast stem cells or placentae. We describe steps for establishing and differentiating murine trophoblast organoids, the characterization of trophoblast organoids in both conditions, the generation of focused single guide RNA (sgRNA) libraries, and the subsequent screening using those libraries in murine trophoblast organoids. For complete details on the use and execution of this protocol, please refer to Mao et al.1.

Development and application of haploid embryonic stem cells

Haploid cells are a kind of cells with only one set of chromosomes. Compared with traditional diploid cells, haploid cells have unique advantages in gene screening and drug-targeted therapy, due to their phenotype being equal to the genotype. Embryonic stem cells are a kind of cells with strong differentiation potential that can differentiate into various types of cells under specific conditions in vitro. Therefore, haploid embryonic stem cells have the characteristics of both haploid cells and embryonic stem cells, which makes them have significant advantages in many aspects, such as reproductive developmental mechanism research, genetic screening, and drug-targeted therapy. Consequently, establishing haploid embryonic stem cell lines is of great significance. This paper reviews the progress of haploid embryonic stem cell research and briefly discusses the applications of haploid embryonic stem cells.