ID proteins promote the survival and primed-to-naive transition of human embryonic stem cells through TCF3-mediated transcription

Do human adipose stem cell-derived artificial insulin-producing cells develop tumorigenic characteristics throughout differentiation?

BACKGROUND

Artificial insulin-producing cells (IPCs) used to treat diabetes mellitus type 1 (DMT1) are naturally hampered by their carcinogenicity. This in vitro study aimed to examine the carcinogenic potential of IPCs produced by the differentiation of human adipose tissue-derived mesenchymal stem cells (hADSCs).

METHODS AND RESULTS

hADSCs were transformed into IPCs by administering insulin-transferrin, selenium (ITS), and nicotinamide in a 14-day differentiation protocol. The cells were transfected with 20 μg of pure Pdx1-pIRES recombinant vector on the tenth day of differentiation. The successful transfection was confirmed by Pdx1 overexpression and GFP fluorescence activity. The differentiated cells' capacity to release insulin and glucose-dependent C-peptide was used to evaluate their functionality. Gene expression was assessed using real-time PCR. Meanwhile, protein expression was investigated using western blotting. The transfected cells exhibited fluorescence activity and Pdx1 overexpression. The differentiated IPCs were able to secrete C-peptide and insulin. The artificial IPCs showed significantly reduced Oct4 and Nanog expression. However, the differentiation process induced a noticeable elevation in tPA expression. The artificial IPCs expressed much lower c-MYC expression compared to undifferentiated hADSCs. The differentiated cells exhibited a significant elevation in Glut2, MMP-2, CD24, P16, and P21 expression.

CONCLUSIONS

The differentiation technique used in this work produced functional beta-like cells devoid of typical markers of stem cells. The synthetic IPCs displayed characteristics of newly generated β-like cells. The artificial IPCs showed no signs of expressing tumor-associated markers. The findings imply that the artificial IPC cells lack tumor characteristics in vitro.

mTORC1 regulates the proliferation of SOX9+ porcine skin-derived stem cells (pSDSCs) by promoting S6K phosphorylation

Skin-derived stem cells (SDSCs) are a subtype of adult stem cells (ASCs) that are widely harvested and exempt from ethical restrictions in clinical applications. These cells possess capabilities for self-renewal, proliferation, and multi-lineage differentiation. Compared to model animals like rats and mice, pigs exhibit greater physiological similarity to humans. Porcine skin has very similar histological and physiological characteristics to human skin. Therefore, porcine skin is becoming increasingly significant as an in vitro model for research. In this study, porcine skin-derived stem cells (pSDSCs) were isolated and cultured in vitro for experiments. The expression of stemness-related gene SOX9 was detected. RNA sequencing (RNA-seq) results found that the mammalian target of rapamycin (mTOR) signaling pathway was significantly enriched in SOX9+ pSDSCs. To investigate the role of the mTOR signaling pathway, we added rapamycin (RAPA), an inhibitor of the mTOR complex 1 (mTORC1), and found that the proliferation rate of SOX9+ pSDSCs decreased significantly during culture. In addition, western blotting (WB) results demonstrated that mTORC1 promoted proliferation by phosphorylating S6 kinase (S6K) and then activating cyclin D1(CCND1) in SOX9+ pSDSCs. These findings provide insights into the mechanisms of adult stem cell proliferation.

Endometrial extracellular vesicles regulate processes related to embryo development and implantation in human blastocysts

STUDY QUESTION

What is the transcriptomic response of human blastocysts following internalization of extracellular vesicles (EVs) secreted by the human endometrium?

SUMMARY ANSWER

EVs secreted by the maternal endometrium induce a transcriptomic response in human embryos that modulates molecular mechanisms related to embryo development and implantation.

WHAT IS KNOWN ALREADY

EVs mediate intercellular communication by transporting various molecules, and endometrial EVs have been postulated to be involved in the molecular regulation of embryo implantation. Our previous studies showed that endometrial EVs carry miRNAs and proteins associated with implantation events that can be taken up by human blastocysts; however, no studies have yet investigated the transcriptomic response of human embryos to this EV uptake, which is crucial to demonstrate the functional significance of this communication system.

STUDY DESIGN, SIZE, DURATION

A prospective descriptive study was performed. Primary human endometrial epithelial cells (pHEECs), derived from endometrial biopsies collected from fertile oocyte donors (n = 20), were cultured in vitro to isolate secreted EVs. Following EV characterization, Day 5 human blastocysts (n = 24) were cultured in the presence or absence of the EVs for 24 h and evaluated by RNA-sequencing.

PARTICIPANTS/MATERIALS, SETTING, METHODS

EVs were isolated from the conditioned culture media using ultracentrifugation, and characterization was performed using western blot, nanoparticle tracking analysis, and transmission electron microscopy. Human blastocysts were devitrified, divided into two groups (n = 12/group), and cultured in vitro for 24 h with or without previously isolated EVs. RNA-sequencing analysis was performed, and DESeq2 was used to identify differentially expressed genes (DEGs) (FDR < 0.05). QIAGEN Ingenuity Pathway Analysis was used to perform the functional enrichment analysis and integration with our recently published data from the pHEECs' EV-miRNA cargo.

MAIN RESULTS AND THE ROLE OF CHANCE

Characterization confirmed the isolation of EVs from pHEECs' conditioned culture media. Among the DEGs in blastocysts co-cultured with EVs, we found 519 were significantly upregulated and 395 were significantly downregulated. These DEGs were significantly enriched in upregulated functions related to embryonic development, cellular invasion and migration, cell cycle, cellular organization and assembly, gene expression, and cell viability; and downregulated functions related to cell death and DNA fragmentation. Further, the intracellular signaling pathways regulated by the internalization of endometrial EVs were previously related to early embryo development and implantation potential, for their role in pluripotency, cellular homeostasis, early embryogenesis, and implantation-related processes. Finally, integrating data from miRNA cargo of EVs, we found that the miRNAs carried by endometrial EVs targeted nearly 80% of the DEGs in human blastocysts.

LIMITATIONS, REASONS FOR CAUTION

This is an in vitro study in which conditions of endometrial cell culture could not mimic the intrauterine environment.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides novel insights into the functional relevance of EVs secreted by the human endometrium, and particularly the role of EV-miRNA regulation on global transcriptome behavior of human blastocysts during early embryogenesis and embryo implantation. It provides potential biomarkers that could become useful diagnostic targets for predicting implantation success.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Spanish Ministry of Education through FPU awarded to M.S.-B. (FPU18/03735), Generalitat Valenciana through VALi+d Programme awarded to M.C.C.-G. (ACIF/2019/139), and Instituto de Salud Carlos III and cofounded by the European Social Fund (ESF) "Investing in your future" through the Miguel Servet Program (CP20/00120 [H.F.]; CP19/00149 [I.C.]). The authors have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Single-nuclei sequencing of uterine serous carcinoma reveals racial differences in immune signaling

Significant racial disparities exist between Black and White patients with uterine serous carcinoma (USC). While the reasons for these disparities are unclear, several studies have demonstrated significantly different rates of driver mutations between racial groups, including TP53. However, limited research has investigated the transcriptional differences of tumors or the composition of the tumor microenvironment (TME) between these groups. Here, we report the single-nuclei RNA-sequencing profiles of primary USC tumors from diverse racial backgrounds. We find that there are significant differences between the tumors of Black and White patients. Tumors from Black patients exhibited higher expression of specific genes associated with aggressiveness, such as PAX8, and axon guidance and synaptic signaling pathways. We also demonstrated that T cell populations are reduced in the tumor tissue compared to matched benign, while anti-inflammatory macrophage populations are retained within the TME. Furthermore, we investigated the connection between PAX8 overexpression and immunosuppression in USC through regulation of several cytokines and chemokines. Notably, we show that PAX8 activity can influence macrophage gene expression and protein secretion. These studies provide a detailed understanding of the USC transcriptome and TME, and identify differences in tumor biology from patients of different racial backgrounds.

BET activity plays an essential role in control of stem cell attributes in Xenopus

Neural crest cells are a stem cell population unique to vertebrate embryos that retains broad multi-germ layer developmental potential through neurulation. Much remains to be learned about the genetic and epigenetic mechanisms that control the potency of neural crest cells. Here, we examine the role that epigenetic readers of the BET (bromodomain and extra terminal) family play in controlling the potential of pluripotent blastula and neural crest cells. We find that inhibiting BET activity leads to loss of pluripotency at blastula stages and a loss of neural crest at neurula stages. We compare the effects of HDAC (an eraser of acetylation marks) and BET (a reader of acetylation) inhibition and find that they lead to similar cellular outcomes through distinct effects on the transcriptome. Interestingly, loss of BET activity in cells undergoing lineage restriction is coupled to increased expression of genes linked to pluripotency and prolongs the competence of initially pluripotent cells to transit to a neural progenitor state. Together these findings advance our understanding of the epigenetic control of pluripotency and the formation of the vertebrate neural crest.

A Keratin 12 Expression-Based Analysis of Stem-Precursor Cells and Differentiation in the Limbal-Corneal Epithelium Using Single-Cell RNA-Seq Data

The corneal epithelium (CE) is spread between two domains, the outer vascularized limbus and the avascular cornea proper. Epithelial cells undergo constant migration from the limbus to the vision-critical central cornea. Coordinated with this migration, the cells undergo differentiation changes where a pool of unique stem/precursor cells at the limbus yields the mature cells that reach the corneal center. Differentiation is heralded by the expression of the corneal-specific Krt12. Processing data acquired by scRNA-Seq showed that the increase in Krt12 expression occurs in four distinct steps within the limbus, plus a single continuous increase in the cornea. Differential gene analysis demonstrated that these domains reflect discreet stages of CE differentiation and yielded extensive information of the genes undergoing down- or upregulation in the sequential transition from less to more differentiate conditions. The approach allowed the identification of multiple gene cohorts, including (a) the genes which have maximal expression in the most primitive, Krt12-negative cell cohort, which is likely to include the stem/precursor cells; (b) the sets of genes that undergo continuous increase or decrease along the whole differentiation path; and (c) the genes showing maximal positive or negative correlation with the changes in Krt12.

Deciphering the distinct transcriptomic and gene regulatory map in adult macaque basal ganglia cells

BACKGROUND

The basal ganglia are a complex of interconnected subcortical structures located beneath the mammalian cerebral cortex. The degeneration of dopaminergic neurons in the basal ganglia is the primary pathological feature of Parkinson's disease. Due to a lack of integrated analysis of multiomics datasets across multiple basal ganglia brain regions, very little is known about the regulatory mechanisms of this area.

FINDINGS

We utilized high-throughput transcriptomic and epigenomic analysis to profile over 270,000 single-nucleus cells to create a cellular atlas of the basal ganglia, characterizing the cellular composition of 4 regions of basal ganglia in adult macaque brain, including the striatum, substantia nigra (SN), globus pallidum, and amygdala. We found a distinct epigenetic regulation on gene expression of neuronal and nonneuronal cells across regions in basal ganglia. We identified a cluster of SN-specific astrocytes associated with neurodegenerative diseases and further explored the conserved and primate-specific transcriptomics in SN cell types across human, macaque, and mouse. Finally, we integrated our epigenetic landscape of basal ganglia cells with human disease heritability and identified a regulatory module consisting of candidate cis-regulatory elements that are specific to medium spiny neurons and associated with schizophrenia.

CONCLUSIONS

In general, our macaque basal ganglia atlas provides valuable insights into the comprehensive transcriptome and epigenome of the most important and populous cell populations in the macaque basal ganglia. We have identified 49 cell types based on transcriptomic profiles and 47 cell types based on epigenomic profiles, some of which exhibit region specificity, and characterized the molecular relationships underlying these brain regions.