The Distinct Role of Tcfs and Lef1 in the Self-Renewal or Differentiation of Mouse Embryonic Stem Cells

LEF1 is associated with immunosuppressive microenvironment of patients with lung adenocarcinoma

Wnt/β-Catenin pathway plays an important role in the occurrence and progression of malignant tumors, especially PD-L1-mediated tumor immune evasion. However, the role of TCF/LEF, an important member of the Wnt/β-catenin pathway, in the tumor immunosuppressive microenvironment of lung adenocarcinoma (LUAD) remains unknown. LUAD tissue-coding RNA expression data from The Cancer Genome Atlas and TIMER databases were used to analyze the expression of TCF/LEF transcription factors and their correlation with various immune cell infiltration. Immunohistochemistry and immunofluorescence were used to detect tissue protein staining in 105 patients with LUAD. LEF1, TCF7, TCF7L1 and TCF7L2 were all aberrantly expressed in the tumor tissues of LUAD patients with the data from The Cancer Genome Atlas (TCGA) database, tumor immune estimation resource (TIMER) database and results of immunohistochemistry, but only LEF1 expression was associated with 5-year overall survival in LUAD patients. LEF1 protein expression was associated with advanced tumor node metastasis (TNM) stage, lymphatic metastasis and local invasion in 105 cases LUAD patients. At the same time, LEF1 mRNA expression was also associated with immunosuppressive microenvironment in LUAD patients with the data from TCGA database and TIMER database. Results of immunohistochemistry and immunofluorescence in tumor tissues of 105 cases LUAD patients showed that there was a positively correlation between LEF1 protein expression and the infiltration of M2 macrophages and Treg cells. LEF1 was highly expressed in tumor tissues of LUAD patients, and highly expressed LEF1 was associated with the immunosuppressive microenvironment of LUAD patients.

CRABP1 Enhances the Proliferation of the Dermal Papilla Cells of Hu Sheep through the Wnt/β-catenin Pathway

BACKGROUND

The homologous proteins identified as cellular retinoic acid-binding proteins I and II (CRABP-I and CRABP-II) belong to a subset of intracellular proteins characterized by their robust affinity for retinoic acid, which plays an indispensable role in the development of hair follicle, including differentiation, proliferation, and apoptosis in keratinocytes. Previous research on Hu sheep hair follicles revealed the specific expression CRABP1 in dermal papilla cells (DPCs), suggesting that CRABP1 has a potential role in regulating the DPC population. Therefore, the main purpose of this study is to expose the performance of the CRABP1 genes in the development and proliferation of DPCs.

METHODS

Initially, overexpression and inhibition of CRABP1 in the DPCs were conducted through overexpression vector and siRNA. CCK-8, EDU, and RT-PCR cell cycle assays and immunostaining were performed to evaluate the proliferation and cell cycle of dermal papilla cells (DPCs). Although, the influence of CRABP1 upon β-catenin in dermal papilla cells (DPCs) was found using immunofluorescence labeling. Finally, RT-PCR was conducted to assess the impact of CRABP1 on the expression levels of CTNNB1, TCF4, and LEF1 in DPCs involved in the Wnt/β-catenin signaling pathway.

RESULTS

The results showed that CRABP1 overexpression promotes the growth rates of DPCs and significantly enhances the proportion of S-phase cells compared with the control group (p < 0.05). The results were the opposite when CRABP1 was a knockdown. In contrast, there was a significant decline in the mRNA expression levels of CTNNβ1, LEF1 (p < 0.05), and TCF4 (p < 0.01) by CRABP1 knockdown.

CONCLUSIONS

This study found that CRABP1 influences the expression of important genes within the Wnt/β-catenin signaling pathway and promotes DPC proliferation. This investigation provides a theoretical framework to explain the mechanisms that control hair follicle morphogenesis and development.

DPPA2/4 Promote the Pluripotency and Proliferation of Bovine Extended Pluripotent Stem Cells by Upregulating the PI3K/AKT/GSK3β/β-Catenin Signaling Pathway

Developmental pluripotency-associated 2 (DPPA2) and DPPA4 are crucial transcription factors involved in maintaining pluripotency in humans and mice. However, the role of DPPA2/4 in bovine extended pluripotent stem cells (bEPSCs) has not been investigated. In this study, a subset of bEPSC-related differentially expressed genes (DEGs), including DPPA2 and DPPA4, was identified based on multiomics data (ATAC-seq and RNA-seq). Subsequent investigations revealed that double overexpression of DPPA2/4 facilitates the reprogramming of bovine fetal fibroblasts (BFFs) into bEPSCs, whereas knockout of DPPA2/4 in BFFs leads to inefficient reprogramming. DPPA2/4 overexpression and knockdown experiments revealed that the pluripotency and proliferation capability of bEPSCs were maintained by promoting the transition from the G1 phase to the S phase of the cell cycle. By activating the PI3K/AKT/GSK3β/β-catenin pathway in bEPSCs, DPPA2/4 can increase the nuclear accumulation of β-catenin, which further upregulates lymphoid enhancer binding factor 1 (LEF1) transcription factor activity. Moreover, DPPA2/4 can also regulate the expression of LEF1 by directly binding to its promoter region. Overall, our results demonstrate that DPPA2/4 promote the reprogramming of BFFs into bEPSCs while also maintaining the pluripotency and proliferation capability of bEPSCs by regulating the PI3K/AKT/GSK3β/β-catenin pathway and subsequently activating LEF1. These findings expand our understanding of the gene regulatory network involved in bEPSC pluripotency.

CRABP2 Promotes the Proliferation of Dermal Papilla Cells via the Wnt/β-Catenin Pathway

In our previous study of Hu sheep hair follicles, we found that CRABP2 was highly expressed in DPCs, which suggested that CRABP2 may influence the number of DPCs. In the present study, we aimed to understand the effect of CRABP2 in Hu sheep dermal papilla cells (DPCs). First, we explored the influence of CRABP2 on the ability of Hu sheep DPCs' proliferation. Based on the results obtained from some experiments, such as CCK-8, EDU, qPCR, and Western blot experiment, we found that the overexpression of CRABP2 facilitated the proliferation of DPCs compared to the negative control group. Then, we also detected the effect of CRABP2 on the Wnt/β-catenin pathway based on the important function of the Wnt/β-catenin pathway in hair follicles. The results showed that CRABP2 could activate the Wnt/β-catenin pathway in DPCs, and it rescues the proliferation of DPCs when the Wnt/β-catenin pathway was inhibited. In summary, our findings indicate that CRABP2 is a vital functional gene in the proliferation of Hu sheep DPCs. Our study will be of great use for revealing the roles of CRABP2 in the hair follicles of Hu sheep.

New insights into the epitranscriptomic control of pluripotent stem cell fate

Each cell in the human body has a distinguishable fate. Pluripotent stem cells are challenged with a myriad of lineage differentiation options. Defects are more likely to be fatal to stem cells than to somatic cells due to the broad impact of the former on early development. Hence, a detailed understanding of the mechanisms that determine the fate of stem cells is needed. The mechanisms by which human pluripotent stem cells, although not fully equipped with complex chromatin structures or epigenetic regulatory mechanisms, accurately control gene expression and are important to the stem cell field. In this review, we examine the events driving pluripotent stem cell fate and the underlying changes in gene expression during early development. In addition, we highlight the role played by the epitranscriptome in the regulation of gene expression that is necessary for each fate-related event.

Roles of Melatonin in Goat Hair Follicle Stem Cell Proliferation and Pluripotency Through Regulating the Wnt Signaling Pathway

Emerging studies show that melatonin promotes cashmere development through hypodermic implantation. However, the impact and underlying mechanisms are currently unknown. In vitro study has previously demonstrated that melatonin induces cashmere growth by regulating the proliferation of goat secondary hair follicle stem cells (gsHFSCs), but there is limited information concerning the effects of melatonin on cell pluripotency. It is also known that Wnt signaling may actively participate in regulating cell proliferation and stem cell pluripotency. Therefore, in the current investigation, goat hair follicle stem cells were exposed to multiple concentrations of melatonin and different culture times to reveal the relationship between melatonin and the activation of Wnt signaling. A proportionally high Catenin beta-1 (CTNNB1) response was induced by 500 ng/L of melatonin, but it was then suppressed with the dosages over 1,000 ng/L. Greater amounts of CTNNB1 entered the cell nuclei by extending the exposure time to 72 h, which activated transcription factor 4/lymphoid enhancer-binding factor 1 and promoted the expression of the proliferation-related genes C-MYC, C-JUN, and CYCLIND1. Moreover, nuclear receptor ROR-alpha (RORα) and bone morphogenetic protein 4 (BMP4) were employed to analyze the underlying mechanism. RORα presented a sluggish concentration/time-dependent rise, but BMP4 was increased dramatically by melatonin exposure, which revealed that melatonin might participate in regulating the pluripotency of hair follicle stem cells. Interestingly, NOGGIN, which is a BMP antagonist and highly relevant to cell stemness, was also stimulated by melatonin. These findings demonstrated that melatonin exposure and/or NOGGIN overexpression in hair follicle stem cells might promote the expression of pluripotency markers Homeobox protein NANOG, Organic cation/carnitine transporter 4, and Hematopoietic progenitor cell antigen CD34. Our findings here provided a comprehensive view of Wnt signaling in melatonin stimulated cells and melatonin mediated stemness of gsHFSCs by regulating NOGGIN, which demonstrates a regulatory mechanism of melatonin enhancement on the growth of cashmere.

The Potential of T Cell Factor 1 in Sustaining CD8+ T Lymphocyte-Directed Anti-Tumor Immunity

Simple Summary

The transcription factor T cell factor 1 (TCF1), encoded by the TCF7 gene, is a key regulator of T-cell fate, which is known to promote T cell proliferation and establish T cell stemness. Importantly, increasing evidence has demonstrated that TCF1 is a critical determinant of the success of anti-tumor immunotherapy, implicating that TCF1 is a promising biomarker and therapeutic target in cancer. In recent years, new findings have emerged to provide a clearer view of TCF1 and its role in T cell biology. In this review, we aim to provide a comprehensive outline of the most recent literature on the role of TCF1 in T cell development and to discuss the potential of TCF1 in sustaining CD8⁺ T lymphocyte-directed anti-tumor immunity.

Abstract

T cell factor 1 (TCF1) is a transcription factor that has been highlighted to play a critical role in the promotion of T cell proliferation and maintenance of cell stemness in the embryonic and CD8⁺ T cell populations. The regulatory nature of TCF1 in CD8⁺ T cells is of great significance, especially within the context of T cell exhaustion, which is linked to the tumor and viral escape in pathological contexts. Indeed, inhibitory signals, such as programmed cell death 1 (PD-1) and cytotoxic-T-lymphocyte-associated protein 4 (CTLA-4), expressed on exhausted T lymphocytes (T_EX), have become major therapeutic targets in immune checkpoint blockade (ICB) therapy. The significance of TCF1 in the sustenance of CTL-mediated immunity against pathogens and tumors, as well as its recently observed necessity for an effective anti-tumor immune response in ICB therapy, presents TCF1 as a potentially significant biomarker and/or therapeutic target for overcoming CD8⁺ T cell exhaustion and resistance to ICB therapy. In this review, we aim to outline the recent findings on the role of TCF1 in T cell development and discuss its implications in anti-tumor immunity.