Trophoblast cells serve as the foundation for placental development. We analyzed published multiomics sequencing data and found that trophoblast cells highly expressed RRS1 compared to primitive endoderm and epiblast. We used HTR-8/SVneo cells for further investigation, and Western blot and immunofluorescence staining confirmed that HTR-8/SVneo cells highly expressed RRS1. RRS1 was successfully knocked down in HTR-8/SVneo cells using siRNA. Using IncuCyte S3 live-cell analysis system based on continuous live-cell imaging and real-time data, we observed that proliferation, migration, and invasion abilities were all significantly decreased in RRS1-knockdown cells. RNA-seq revealed that knockdown of RRS1 affected the gene transcription, and upregulated pathways in extracellular matrix organization, DNA damage response, and intrinsic apoptotic signaling, downregulated pathways in embryo implantation, trophoblast cell migration, and wound healing. Differentially expressed genes were enriched in diseases related to placental development. Consistent with these findings, human chorionic villus samples collected from spontaneous abortion cases exhibited significantly reduced RRS1 expression compared to normal controls. Our results highlight the functional importance of RRS1 in human trophoblasts and suggest that its deficiency contributes to early pregnancy loss.
Humans ; Trophoblasts/physiology* ; Cell Movement/genetics* ; Cell Proliferation/genetics* ; Female ; Pregnancy ; Abortion, Spontaneous/metabolism* ; Cell Line ; Placentation/genetics*

OBJECTIVE: To assess the feasibility of first polar body transfer (PB1T) combined with preimplantation mitochondrial genetic testing for blocking the transmission of a pathogenic mitochondrial DNA 8993T>G mutation. METHODS: A Chinese family affected with Leigh syndrome which had attended the Reproductive Medicine Centre of the First Affiliated Hospital of Anhui Medical University in September 2021 was selected as the study subject. Controlled ovarian hyperstimulation was carried out for the proband after completing the detection of the mitochondrial DNA 8993T>G mutation load among the pedigree members. Mature MII oocytes were inseminated by intracytoplasmic sperm injection (ICSI), cultured in vitro for 5 to 6 days to the blastocyst stage, and trophoblastocytes were obtained by microbiopsy. Mitochondrial DNA testing (PGT-MT) and chromosomal aneuploidy (PGT-A) analyses were carried out after whole-genome amplification, and the embryos with zero mutation load were selected for transfer. Amniotic fluid and umbilical cord blood samples were collected during middle pregnancy and after birth respectively for mitochondrial DNA testing to verify the reliability of embryo screening. As an attempt, PB1 with good morphology of MII oocytes was selected for transfer into the enucleated oocytoplasm from healthy donors, followed by ICSI fertilization, blastocyst culture and PGT of embryos using the same procedure. This study has been approved by the Ethics Committee of the First Affiliated Hospital of Anhui Medical University (No. 2021zhyx-B12). RESULTS: An antagonist protocol was used for ovarian stimulation, and a total of 19 oocytes were obtained, of which 14 MII were fertilized by ICSI, and 2 had developed into blastocysts. PGT-MT was carried out on biopsied trophoblastocytes, in which the mitochondrial DNA 8993T>G mutation load was not detected in one embryo, the other was 100% mutated, and the mutation loads of the remaining unfertilized eggs and developmentally arrested embryos ranged from 0% ~ 100%, presenting a clear biased distribution. With fully informed consent, one PGT-MT zero mutation load blastocyst was transferred and clinical pregnancy was achieved. Mitochondrial DNA and chromosomal testing of amniotic fluid cells during middle pregnancy had revealed no abnormalities. The proband had delivered a healthy boy through Caesarean section at 39⁺⁵ weeks of gestation, and no mutation was detected in the cord blood sample. Five well-formed PBs from 14 eggs were selected for PB1 transfer, followed by ICSI and culture, and two of the reconstituted embryos had formed blastocysts, with none of the above mutations detected in the biopsied samples. CONCLUSION The PGT-MT technology can help families affected with mitochondrial diseases to have healthy offspring. PB1 transfer in combination with ICSI and PGT-MT holds the promise of turning waste into treasure and providing an alternative means of fertility for such families.
Humans ; Preimplantation Diagnosis/methods* ; Female ; DNA, Mitochondrial/genetics* ; Genetic Testing/methods* ; Pregnancy ; Mitochondrial Diseases/genetics* ; Polar Bodies ; Adult ; Feasibility Studies ; Sperm Injections, Intracytoplasmic/methods* ; Embryo Transfer/methods* ; Mutation ; Male ; Blastocyst/metabolism* ; Pedigree

OBJECTIVE: To analyze the chromosome status of pre-implantation embryos from women of different ages, and assess the impact of age on it. METHODS: A retrospective analysis was carried out on the results of PGT-A and PGT-M+PGT-A cycles by whole-genome amplification followed by next generation sequencing at the Second People's Hospital of Nanning between July 2021 and November 2023. The embryos were divided into five groups based on the women's age: ≤ 30 years old group, 31 ~ 34 years old group, 35 ~ 37 years old group, 38 ~ 40 years old group, and ≥ 41 years old group.The chromosomal status of embryos for each group was compared. This study has been approved by the Ethic Committee of the Hospital (Ethics No. Y2024312A). RESULTS: This study has involved 390 couples and 436 PGT cycles, with a total of 1 651 blastocysts biopsied and analyzed. Among these, 835 embryos (50.6%) were found to have chromosomal abnormalities, including 490 (29.7%) with aneuploidies, 154 (9.3%) with chromosomal segment abnormalities, and 264 (16.0%) with chromosome mosaicisms. After adjusting the dosages of Gn, female BMI, male age, PGT indications, infertility type, LH, AMH and other parameters, maternal age appeared to be an independent factor for chromosomal abnormalities and aneuploidies in blastocysts (OR = 1.132, 95%CI = 1.089-1.177, P < 0.001; OR = 1.250, 95%CI = 1.188-1.315, P < 0.001). With the increase in female age, embryonic chromosome abnormalities have significantly increased in each group, with the rates being 32.3% (126/390), 43.1% (189/439), 45.1% (116/257), 66.3% (250/377), and 81.9% (154/188) (P < 0.001). Chromosomal aneuploidies have also significantly increased, with the rates being 8.2% (32/390), 16.6% (73/439), 24.5% (63/257), 49.6% (187/377), and 71.8% (135/188) (P < 0.001). The proportion of embryos with ≥ 2 chromosome abnormalities also significantly increased in abnormal embryos, with the rates being 28.6% (36/126), 30.2% (57/189), 39.7% (46/116), 48.4% (121/250), and 64.9% (100/154) (P < 0.001). Of note, the female age did not affect the prevalence of chromosomal segment abnormalities and mosaicisms (all P > 0.05). CONCLUSION Above findings suggested that along with the increase in female age, there is an increase in the rate and complexity of chromosomal abnormalities, which may contribute to infertility in women with elder age.
Humans ; Female ; Maternal Age ; Adult ; Retrospective Studies ; Chromosome Aberrations ; Preimplantation Diagnosis/methods* ; Pregnancy ; Blastocyst/metabolism* ; Aneuploidy ; Fertilization in Vitro ; Male

Approximately 140 million people worldwide are homozygous carriers of APOE4 (ε4), a strong genetic risk factor for late onset familial and sporadic Alzheimer's disease (AD), 91% of whom will develop AD at earlier age than heterozygous carriers and noncarriers. Susceptibility to AD could be reduced by targeted editing of APOE4, but a technical basis for controlling the off-target effects of base editors is necessary to develop low-risk personalized gene therapies. Here, we first screened eight cytosine base editor variants at four injection stages (from 1- to 8-cell stage), and found that FNLS-YE1 variant in 8-cell embryos achieved the comparable base conversion rate (up to 100%) with the lowest bystander effects. In particular, 80% of AD-susceptible ε4 allele copies were converted to the AD-neutral ε3 allele in human ε4-carrying embryos. Stringent control measures combined with targeted deep sequencing, whole genome sequencing, and RNA sequencing showed no DNA or RNA off-target events in FNLS-YE1-treated human embryos or their derived stem cells. Furthermore, base editing with FNLS-YE1 showed no effects on embryo development to the blastocyst stage. Finally, we also demonstrated FNLS-YE1 could introduce known protective variants in human embryos to potentially reduce human susceptivity to systemic lupus erythematosus and familial hypercholesterolemia. Our study therefore suggests that base editing with FNLS-YE1 can efficiently and safely introduce known preventive variants in 8-cell human embryos, a potential approach for reducing human susceptibility to AD or other genetic diseases.
Humans ; Apolipoprotein E4/genetics* ; Cytosine ; Mutation ; Blastocyst ; Heterozygote ; Gene Editing ; CRISPR-Cas Systems

Accumulating studies have demonstrated that non-coding RNAs (ncRNAs), functioning as important regulators of transcription and translation, are involved in the establishment and maintenance of pregnancy, especially the maternal immune adaptation process. The endometrial stromal cells (ESCs), trophoblast cells, and decidua immune cells that reside at the maternal-fetal interface are thought to play significant roles in normal pregnancy and pregnancy-associated diseases. Here, we reviewed the up-to-date evidence on how microRNA, long non-coding RNA, and circular RNA regulate ESCs, trophoblast cells, and immune cells and discussed the potential applications of these ncRNAs as diagnostic and therapeutic markers in pregnancy complications.
Pregnancy ; Female ; Humans ; MicroRNAs/genetics* ; RNA, Long Noncoding/genetics* ; RNA, Circular/genetics* ; Trophoblasts ; Pregnancy Complications/genetics*

Humans ; Consensus ; Blastocyst ; Embryonic Development ; Fertilization in Vitro

Chromosomal mosaicism (CM) is a common phenomenon in preimplantation genetic testing (PGT). In embryos with CM, genetic contents of trophoblastic ectodermal (TE) cells may be different from that of the inner cell mass (ICM) which will develop into the fetus. Embryos with low mosaic proportion could give rise to healthy live births after transplantation, but are accompanied with high pregnancy risks such as high abortion rate. In order to provide a more comprehensive understanding for CM embryos, this article has systematically summarized the recent progress of research on the definition, mechanism, classification, PGT techniques, self-correction mechanism, transplantation outcome and treatment principles for CM embryos.
Pregnancy ; Female ; Humans ; Preimplantation Diagnosis/methods* ; Mosaicism ; Aneuploidy ; Genetic Testing/methods* ; Blastocyst

Self-organized blastoids from extended pluripotent stem (EPS) cells possess enormous potential for investigating postimplantation embryo development and related diseases. However, the limited ability of postimplantation development of EPS-blastoids hinders its further application. In this study, single-cell transcriptomic analysis indicated that the "trophectoderm (TE)-like structure" of EPS-blastoids was primarily composed of primitive endoderm (PrE)-related cells instead of TE-related cells. We further identified PrE-like cells in EPS cell culture that contribute to the blastoid formation with TE-like structure. Inhibition of PrE cell differentiation by inhibiting MEK signaling or knockout of Gata6 in EPS cells markedly suppressed EPS-blastoid formation. Furthermore, we demonstrated that blastocyst-like structures reconstituted by combining the EPS-derived bilineage embryo-like structure (BLES) with either tetraploid embryos or tetraploid TE cells could implant normally and develop into live fetuses. In summary, our study reveals that TE improvement is critical for constructing a functional embryo using stem cells in vitro.
Pregnancy ; Female ; Animals ; Mice ; Tetraploidy ; Blastocyst ; Embryo, Mammalian ; Cell Differentiation ; Embryonic Development

Human pluripotent stem cells provide an inexhaustible model to study human embryogenesis in vitro. Recent studies have provided diverse models to generate human blastoids by self-organization of different pluripotent stem cells or somatic reprogramming intermediates. However, whether blastoids can be generated from other cell types or whether they can recapitulate postimplantation development in vitro is unknown. Here, we develop a strategy to generate human blastoids from heterogeneous intermediates with epiblast, trophectoderm, and primitive endoderm signatures of the primed-to-naïve conversion process, which resemble natural blastocysts in morphological architecture, composition of cell lineages, transcriptome, and lineage differentiation potential. In addition, these blastoids reflect many features of human peri-implantation and pregastrulation development when further cultured in an in vitro 3D culture system. In summary, our study provides an alternative strategy to generate human blastoids and offers insights into human early embryogenesis by modeling peri- and postimplantation development in vitro.
Humans ; Pluripotent Stem Cells/metabolism* ; Embryo, Mammalian/metabolism* ; Cell Differentiation ; Blastocyst ; Cell Lineage ; Embryonic Development

OBJECTIVE: To assess the value of single sperm sequencing in preimplantation genetic testing for monogenic disease (PGT-M). METHODS: A Chinese couple with two children whom had died of Spinal muscular atrophy (SMA) and attended the Jiangxi Provincial Maternal and Child Health Care Hospital in June 2020 was selected as the subject. Eleven single sperm samples were isolated by mechanical immobilization and subjected to whole genome amplification. Real-time PCR and Sanger sequencing were used to detect the SMN1 variants in the single sperm samples. Genomic DNA of the wife, her parents and the husband, as well as one single sperm sample harboring the SMN1 variant and two single sperm samples without the variant were used for the linkage analysis. Targeted capture and high-throughput sequencing were carried out to test 100 single nucleotide polymorphisms distributed within 2 Mb up- and downstream the variant site. The haplotypes linked with the SMN1 variants were determined by linkage analysis. Blastocyst embryos were harvested after fertilizing by intracytoplasmic sperm injection. Cells from the trophoblasts of each embryo were biopsied and subjected to whole genome amplification and targeted capture and high-throughput sequencing to determine their carrier status. Chromosomal aneuploidy of wild-type embryos was excluded. An euploid embryo of high quality was transferred. Amniotic fluid sample was taken at 18 weeks of gestation to confirm the status of the fetus. RESULTS: Genetic testing showed that the couple both had deletion of exons 7 ~ 8 of the SMN1 gene. The wife has inherited the deletion from her father, while the husband was de novo. The haplotypes of the husband were successfully constructed by single sperm sequencing. Preimplantation genetic testing has indicated that 5 embryos had harbored the heterozygous variant, 4 embryos were of the wild type, among which 3 were euploid. Prenatal diagnosis during the second trimester of pregnancy has confirmed that the fetus did not carry the deletion. CONCLUSION By single sperm sequencing and PGT-M, the birth of further affected child has been successfully avoided.
Humans ; Pregnancy ; Female ; Child ; Male ; Preimplantation Diagnosis ; East Asian People ; Semen ; Genetic Testing ; Muscular Atrophy, Spinal/genetics* ; Aneuploidy ; Blastocyst/pathology* ; High-Throughput Nucleotide Sequencing ; Spermatozoa