Background: Little is known on the tumor microenvironment (TME) response after neoadjuvant chemotherapy (NACT) in gastric cancer on the molecular level. Methods: Here, we profiled 33,589 cell transcriptomes in 14 samples from 11 gastric cancer patients (4 pre-treatment samples, 4 post-treatment samples and 3 pre-post pairs) using single-cell RNA sequencing (scRNA-seq) to generate the cell atlas. The ligand-receptor-based intercellular communication networks of the single cells were also characterized before and after NACT. Results: Compered to pre-treatment samples, CD4+ T cells (P = 0.018) and CD8+ T cells (P = 0.010) of post-treatment samples were significantly decreased, while endothelial cells and fibroblasts were increased (P = 0.034 and P = 0.005, respectively). No significant difference observed with respect to CD4+ Tregs cells, cycling T cells, B cells, plasma cells, macrophages, monocytes, dendritic cells, and mast cells (P > 0.05). In the unsupervised nonnegative matrix factorization (NMF) analysis, we revealed that there were three transcriptional programs (NMF1, NMF2 and NMF3) shared among these samples. Compared to pre-treatment samples, signature score of NMF1 was significantly downregulated after treatment (P = 0.009), while the NMF2 signature was significantly upregulated after treatment (P = 0.013). The downregulated NMF1 and upregulated NMF2 signatures were both associated with improved overall survival outcomes based on The Cancer Genome Atlas (TCGA) database. Additionally, proangiogenic pathways were activated in tumor and endothelial cells after treatment, indicating that NACT triggers vascular remodeling by cancer cells together with stromal cells. Conclusions: In conclusion, our study provided transcriptional profiles of TME between pre-treatment and post-treatment for in-depth understanding on the mechanisms of NACT in gastric cancer and empowering the development of potential optimized therapy procedures and novel drugs.

Infertility has become a global health issue, with the number of people suffering from the disease increasing year by year, and ART offering great promise for infertility treatment. However, the regulation of early embryonic development is complicated and a series of processes takes place, including the maternal-to-zygotic transition. In addition, developmental arrest is frequently observed during human early embryonic development. In this study, we performed single-cell RNA sequencing on a biopsied blastomere from human eight-cell embryos and tracked the developmental potential of the remaining cells. To compare the sequencing results between different eight-cell embryos, we have combined the research data of this project with the data previously shared in the database and found that cells from the same embryo showed a higher correlation. Additionally, the transcriptome of embryos with blastocyst formation failure was significantly different from developed embryos, and the gene expression as well as cell signaling pathways related to embryonic development were also altered. In particular, the expression of some maternal and zygotic genes in the failed blastocyst formation group was significantly altered: the overall expression level of maternal genes was significantly higher in the failed blastocyst than the developed blastocyst group. In general, these findings provide clues for the causes of human embryonic arrest after the eight-cell stage, and they also provide new ideas for improving the success rate of ART in clinical practice.

BACKGROUND: Preeclampsia, a life-threatening hypertensive disorder of pregnancy, has been linked to iron dysregulation, though mechanistic insights remain limited. METHODS: We integrated clinical data, a reduced uterine perfusion pressure mouse model, in vitro trophoblast cell experiments, and placental organoids derived from patients with preeclampsia. Iron metabolism was assessed via mass spectrometry, quantitative polymerase chain reaction, Peris’ Prussian blue staining and immunohistochemistry. Ferroptosis markers and iron transporters were analyzed. Interventions included the iron chelator deferoxamine, antioxidant MitoQ, ferroptosis inhibitor Fer-1 (ferrostatin-1), and the apoptosis inhibitor Z-VAD. RESULTS: Patients with preeclampsia exhibited elevated hemoglobin, ferritin, and serum iron levels from the second trimester, alongside placental iron overload. Single-cell/nucleus RNA sequencing revealed dysregulated iron transporters ( TFRC ↑, DMT1 ↑, FPN ↓) in preeclampsia trophoblasts. Iron overload induced ferroptosis and apoptosis in trophoblasts, evidenced by increased lipid peroxidation (4HNE↑, Gpx4↓), ROS, Tunnel staining positive and cell death, while suppressing PlGF and progesterone secretion. Both deferoxamine and MitoQ rescued these effects in vitro (similar to Ferr-1) and in preeclampsia-derived organoids. The reduced uterine perfusion pressure model confirmed the preservation of iron dyshomeostasis and ferroptosis in preeclamptic placentas, while oral administration of MitoQ was found to reduce 4-hydroxynonenal and malondialdehyde expression in placenta. CONCLUSIONS: Our findings reveal that iron overload and subsequent ferroptosis contribute to placental damage in preeclampsia, suggesting that iron metabolism dysregulation is a critical feature of the disease. This highlights the need to reevaluate iron supplementation protocols in high-risk pregnancies and to consider individualized iron management strategies that balance maternal-fetal iron requirements while minimizing oxidative stress.

Gametogenesis plays an important role in the reproduction and evolution of species. The transcriptomic and epigenetic alterations in this process can influence the reproductive capacity, fertilization, and embryonic development. The rapidly increasing single-cell studies have provided valuable multi-omics resources. However, data from different layers and sequencing platforms have not been uniformed and integrated, which greatly limits their use for exploring the molecular mechanisms that underlie oogenesis and spermatogenesis. Here, we develop GametesOmics, a comprehensive database that integrates the data of gene expression, DNA methylation, and chromatin accessibility during oogenesis and spermatogenesis in humans and mice. GametesOmics provides a user-friendly website and various tools, including Search and Advanced Search for querying the expression and epigenetic modification(s) of each gene; Tools with Differentially expressed gene (DEG) analysis for identifying DEGs, Correlation analysis for demonstrating the genetic and epigenetic changes, Visualization for displaying single-cell clusters and screening marker genes as well as master transcription factors (TFs), and MethylView for studying the genomic distribution of epigenetic modifications. GametesOmics also provides Genome Browser and Ortholog for tracking and comparing gene expression, DNA methylation, and chromatin accessibility between humans and mice. GametesOmics offers a comprehensive resource for biologists and clinicians to decipher the cell fate transition in germ cell development, and can be accessed at http://gametesomics.cn/.

The births of more than 8 million infants have been enabled globally through assisted reproductive technologies (ARTs), including conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) with either fresh embryo transfer (ET) or frozen embryo transfer (FET). However, the potential for elevated risks of ART-related disorders persists in adult life, and the underlying epigenetic mechanisms are largely uncharacterized. Here, we recruited 100 nuclear families and profiled the DNA methylomes, genome-wide histone modifications and transcriptomes to clarify the inherent extra risks attributable to specific ART procedures. We discovered that IVF-ET seemed to introduce less disturbance into the infant epigenome than IVF-FET or ICSI-ET did. Furthermore, we noted approximately half of the DNA methylomic changes in ART-conceived offspring could be explained by parental background biases. Through removal of the parental effect, we confirmed that ART per se would introduce minor DNA methylation changes locally. More importantly, we found that ART-induced epigenomic alterations were highly enriched in the processes which might contribute to increased incidence of preeclampsia during pregnancy and metabolic syndrome in offspring. Overall, our study provides an epigenetic basis for the potential long-term health risks in ART-conceived offspring that reinforces the need to review all methods of human ART.

Gametogenesis plays an important role in the reproduction and evolution of species. The transcriptomic and epigenetic alterations in this process can influence the reproductive capacity, fertilization, and embryonic development. The rapidly increasing single-cell studies have provided valuable multi-omics resources. However, data from different layers and sequencing platforms have not been uniformed and integrated, which greatly limits their use for exploring the molecular mechanisms that underlie oogenesis and spermatogenesis. Here, we developed GametesOmics, a comprehensive database that integrated the data of gene expression, DNA methylation, and chromatin accessibility during oogenesis and spermatogenesis in humans and mice. GametesOmics provides a user-friendly website and various tools, including Search and Advanced Search for querying the expression and epigenetic modification of each gene; Analysis Tools with Differentially Expressed Gene (DEG) analysis for identifying DEGs, Correlation analysis for demonstrating the genetic and epigenetic changes, Visualization for displaying single-cell cluster and screening marker genes as well as master transcription factors (TFs), and MethylView for studying the genomic distribution of epigenetic modifications. GametesOmics also provides Genome Browser and Orthologs for tracking and comparing gene expression, DNA methylations, as well as chromatin accessibilities between humans and mice. GametesOmics offers a comprehensive resource for biologists and clinicians to decipher the cell fate transition in germ cell development, and can be accessed at http://gametesomics.cn/ .