Selenium Drives a Transcriptional Adaptive Program to Block Ferroptosis and Treat Stroke.

Ferroptosis, a non-apoptotic form of programmed cell death, is triggered by oxidative stress in cancer, heat stress in plants, and hemorrhagic stroke. A homeostatic transcriptional response to ferroptotic stimuli is unknown. We show that neurons respond to ferroptotic stimuli by induction of selenoproteins, including antioxidant glutathione peroxidase 4 (GPX4). Pharmacological selenium (Se) augments GPX4 and other genes in this transcriptional program, the selenome, via coordinated activation of the transcription factors TFAP2c and Sp1 to protect neurons. Remarkably, a single dose of Se delivered into the brain drives antioxidant GPX4 expression, protects neurons, and improves behavior in a hemorrhagic stroke model. Altogether, we show that pharmacological Se supplementation effectively inhibits GPX4-dependent ferroptotic death as well as cell death induced by excitotoxicity or ER stress, which are GPX4 independent. Systemic administration of a brain-penetrant selenopeptide activates homeostatic transcription to inhibit cell death and improves function when delivered after hemorrhagic or ischemic stroke.

A polymorphism in IRF4 affects human pigmentation through a tyrosinase-dependent MITF/TFAP2A pathway.

Sequence polymorphisms linked to human diseases and phenotypes in genome-wide association studies often affect noncoding regions. A SNP within an intron of the gene encoding Interferon Regulatory Factor 4 (IRF4), a transcription factor with no known role in melanocyte biology, is strongly associated with sensitivity of skin to sun exposure, freckles, blue eyes, and brown hair color. Here, we demonstrate that this SNP lies within an enhancer of IRF4 transcription in melanocytes. The allele associated with this pigmentation phenotype impairs binding of the TFAP2A transcription factor that, together with the melanocyte master regulator MITF, regulates activity of the enhancer. Assays in zebrafish and mice reveal that IRF4 cooperates with MITF to activate expression of Tyrosinase (TYR), an essential enzyme in melanin synthesis. Our findings provide a clear example of a noncoding polymorphism that affects a phenotype by modulating a developmental gene regulatory network.

TFAP2 paralogs regulate midfacial development in part through a conserved ALX genetic pathway.

Cranial neural crest development is governed by positional gene regulatory networks (GRNs). Fine-tuning of the GRN components underlies facial shape variation, yet how those networks in the midface are connected and activated remain poorly understood. Here, we show that concerted inactivation of Tfap2a and Tfap2b in the murine neural crest, even during the late migratory phase, results in a midfacial cleft and skeletal abnormalities. Bulk and single-cell RNA-seq profiling reveal that loss of both TFAP2 family members dysregulates numerous midface GRN components involved in midface morphogenesis, patterning and differentiation. Notably, Alx1, Alx3 and Alx4 (ALX) transcript levels are reduced, whereas ChIP-seq analyses suggest TFAP2 family members directly and positively regulate ALX gene expression. Tfap2a, Tfap2b and ALX co-expression in midfacial neural crest cells of both mouse and zebrafish implies conservation of this regulatory axis across vertebrates. Consistent with this notion, tfap2a zebrafish mutants present with abnormal alx3 expression patterns, Tfap2a binds ALX loci and tfap2a-alx3 genetic interactions are observed. Together, these data demonstrate TFAP2 paralogs regulate vertebrate midfacial development in part by activating expression of ALX transcription factor genes.

Transcription factor-based transdifferentiation of human embryonic to trophoblast stem cells.

During the first week of development, human embryos form a blastocyst composed of an inner cell mass and trophectoderm (TE) cells, the latter of which are progenitors of placental trophoblast. Here, we investigated the expression of transcripts in the human TE from early to late blastocyst stages. We identified enrichment of the transcription factors GATA2, GATA3, TFAP2C and KLF5 and characterised their protein expression dynamics across TE development. By inducible overexpression and mRNA transfection, we determined that these factors, together with MYC, are sufficient to establish induced trophoblast stem cells (iTSCs) from primed human embryonic stem cells. These iTSCs self-renew and recapitulate morphological characteristics, gene expression profiles, and directed differentiation potential, similar to existing human TSCs. Systematic omission of each, or combinations of factors, revealed the crucial importance of GATA2 and GATA3 for iTSC transdifferentiation. Altogether, these findings provide insights into the transcription factor network that may be operational in the human TE and broaden the methods for establishing cellular models of early human placental progenitor cells, which may be useful in the future to model placental-associated diseases.

miR-137 confers robustness to the territorial restriction of the neural plate border.

The neural plate border (NPB) of vertebrate embryos is segregated from the neural plate (NP) and epidermal regions, and comprises an intermingled group of progenitors with multiple fate potential. Recent studies have shown that, during the gastrula stage, TFAP2A acts as a pioneer factor in remodeling the epigenetic landscape required to activate components of the NPB induction program. Here, we show that chick Tfap2a has two highly conserved binding sites for miR-137, and both display a reciprocal expression pattern at the NPB and NP, respectively. In addition, ectopic miR-137 expression reduced TFAP2A, whereas its functional inhibition expanded their territorial distribution overlapping with PAX7. Furthermore, we demonstrate that loss of the de novo DNA methyltransferase DNMT3A expanded miR-137 expression to the NPB. Bisulfite sequencing revealed a markedly elevated presence of non-canonical CpH methylation within the miR-137 promoter region when comparing NPB and NP samples. Our findings show that miR-137 contributes to the robustness of NPB territorial restriction in vertebrate development.

Transcriptional programs of Pitx2 and Tfap2a/Tfap2b controlling lineage specification of mandibular epithelium during tooth initiation.

How the dorsal-ventral axis of the vertebrate jaw, particularly the position of tooth initiation site, is established remains a critical and unresolved question. Tooth development starts with the formation of the dental lamina, a localized thickened strip within the maxillary and mandibular epithelium. To identify transcriptional regulatory networks (TRN) controlling the specification of dental lamina from the naïve mandibular epithelium, we utilized Laser Microdissection coupled low-input RNA-seq (LMD-RNA-seq) to profile gene expression of different domains of the mandibular epithelium along the dorsal-ventral axis. We comprehensively identified transcription factors (TFs) and signaling pathways that are differentially expressed along mandibular epithelial domains (including the dental lamina). Specifically, we found that the TFs Sox2 and Tfap2 (Tfap2a/Tfap2b) formed complimentary expression domains along the dorsal-ventral axis of the mandibular epithelium. Interestingly, both classic and novel dental lamina specific TFs-such as Pitx2, Ascl5 and Zfp536-were found to localize near the Sox2:Tfap2a/Tfap2b interface. To explore the functional significance of these domain specific TFs, we next examined loss-of-function mouse models of these domain specific TFs, including the dental lamina specific TF, Pitx2, and the ventral surface ectoderm specific TFs Tfap2a and Tfap2b. We found that disruption of domain specific TFs leads to an upregulation and expansion of the alternative domain's TRN. The importance of this cross-repression is evident by the ectopic expansion of Pitx2 and Sox2 positive dental lamina structure in Tfap2a/Tfap2b ectodermal double knockouts and the emergence of an ectopic tooth in the ventral surface ectoderm. Finally, we uncovered an unappreciated interface of mesenchymal SHH and WNT signaling pathways, at the site of tooth initiation, that were established by the epithelial domain specific TFs including Pitx2 and Tfap2a/Tfap2b. These results uncover a previously unknown molecular mechanism involving cross-repression of domain specific TFs including Pitx2 and Tfap2a/Tfap2b in patterning the dorsal-ventral axis of the mouse mandible, specifically the regulation of tooth initiation site.

Dissecting the role of transcription factor AP2-M in Babesia asexual replication.

Babesia spp. are obligate intracellular parasites that invade host cells to complete their asexual development and transmission. Here, we identified a transcription factor AP2-M (BXIN_0799) in Babesia sp. Xinjiang (Bxj), a member of the Apicomplexan AP2 family, which regulates gene expression related to red blood cell (RBC) invasion and cell cycle progression. Our genome-wide analysis of (Cut-Tag) data shows that AP2-M specifically recognized DNA motifs in the promoters of target genes. AP2-M target genes included other AP2 gene family members and epigenetic markers, which could modulate gene expression involved in RBC invasion, merozoite morphology, and cell cycle phases, as indicated by RNA sequencing, proteomics, and single-cell RNA sequencing (scRNA-seq) data from an ap2-m gene disrupted strain (AP2-M (-)). We conclude that AP2-M appeared to contribute to the process of red blood cell invasion, maintain merozoite morphology, and cell cycle progression through GS and MS phases.

PRDM14 extinction enables the initiation of trophoblast stem cell formation.

Trophoblast stem cells (TSCs) can be chemically converted from embryonic stem cells (ESCs) in vitro. Although several transcription factors (TFs) have been recognized as essential for TSC formation, it remains unclear how differentiation cues link elimination of stemness with the establishment of TSC identity. Here, we show that PRDM14, a critical pluripotent circuitry component, is reduced during the formation of TSCs. The reduction is further shown to be due to the activation of Wnt/ß-catenin signaling. The extinction of PRDM14 results in the erasure of H3K27me3 marks and chromatin opening in the gene loci of TSC TFs, including GATA3 and TFAP2C, which enables their expression and thus the initiation of the TSC formation process. Accordingly, PRDM14 reduction is proposed here as a critical event that couples elimination of stemness with the initiation of TSC formation. The present study provides novel insights into how induction signals initiate TSC formation.

Structural basis for specific DNA sequence motif recognition by the TFAP2 transcription factors.

The TFAP2 family regulates gene expression during differentiation, development, and organogenesis, and includes five homologs in humans. They all possess a highly conserved DNA binding domain (DBD) followed by a helix-span-helix (HSH) domain. The DBD-HSH tandem domain specifically binds to a GCC(N3)GGC consensus sequence, but the precise recognition mechanisms remain unclear. Here, we found that TFAP2 preferred binding to the GCC(N3)GGC sequence, and the pseudo-palindromic GCC and GGC motifs and the length of the central spacer between the two motifs determined their binding specificity. Structural studies revealed that the two flat amphipathic α-helical HSH domains of TFAP2A stacked with each other to form a dimer via hydrophobic interactions, while the stabilized loops from both DBD domains inserted into two neighboring major grooves of the DNA duplex to form base-specific interactions. This specific DNA binding mechanism controlled the length of the central spacer and determined the DNA sequence specificity of TFAP2. Mutations of the TFAP2 proteins are implicated in various diseases. We illustrated that reduction or disruption of the DNA binding ability of the TFAP2 proteins is the primary cause of TFAP2 mutation-associated diseases. Thus, our findings also offer valuable insights into the pathogenesis of disease-associated mutations in TFAP2 proteins.

Tyrosine phosphorylation-mediated YAP1-TFAP2A interactions coordinate transcription and trastuzumab resistance in HER2+ breast cancer.

Trastuzumab resistance in HER2+ breast cancer (BC) is the major reason leading to poor prognosis of BC patients. Oncogenic gene overexpression or aberrant activation of tyrosine kinase SRC is identified to be the key modulator of trastuzumab response. However, the detailed regulatory mechanisms underlying SRC activation-associated trastuzumab resistance remain poorly understood. In the present study, we discover that SRC-mediated YAP1 tyrosine phosphorylation facilitates its interaction with transcription factor AP-2 alpha (activating enhancer binding protein 2 alpha, TFAP2A), which in turn promotes YAP1/TEAD-TFAP2A (YTT) complex-associated transcriptional outputs, thereby conferring trastuzumab resistance in HER2+ BC. Inhibition of SRC kinase activity or disruption of YTT complex sensitizes cells to trastuzumab treatment in vitro and in vivo. Additionally, we also identify YTT complex co-occupies the regulatory regions of a series of genes related to trastuzumab resistance and directly regulates their transcriptions, including EGFR, HER2, H19 and CTGF. Moreover, YTT-mediated transcriptional regulation is coordinated by SRC kinase activity. Taken together, our study reveals that SRC-mediated YTT complex formation and transcriptions are responsible for multiple mechanisms associated with trastuzumab resistance. Therefore, targeting HER2 signaling in combination with the inhibition of YTT-associated transcriptional outputs could serve as the treatment strategy to overcome trastuzumab resistance caused by SRC activation.

Genetic variation that determines TAPBP expression levels associates with the course of malaria in an HLA allotype-dependent manner.

HLA class I (HLA-I) allotypes vary widely in their dependence on tapasin (TAPBP), an integral component of the peptide-loading complex, to present peptides on the cell surface. We identified two single-nucleotide polymorphisms that regulate TAPBP messenger RNA (mRNA) expression in Africans, rs111686073 (G/C) and rs59097151 (A/G), located in an AP-2α transcription factor binding site and a microRNA (miR)-4486 binding site, respectively. rs111686073G and rs59097151A induced significantly higher TAPBP mRNA expression relative to the alternative alleles due to higher affinity for AP-2α and abrogation of miR-4486 binding, respectively. These variants associated with lower Plasmodium falciparum parasite prevalence and lower incidence of clinical malaria specifically among individuals carrying tapasin-dependent HLA-I allotypes, presumably by augmenting peptide loading, whereas tapasin-independent allotypes associated with relative protection, regardless of imputed TAPBP mRNA expression levels. Thus, an attenuated course of malaria may occur through enhanced breadth and/or magnitude of antigen presentation, an important consideration when evaluating vaccine efficacy.

Transcription factor AP-2α activates RNA polymerase III-directed transcription and tumor cell proliferation by controlling expression of c-MYC and p53.

Deregulation of transcription factor AP2 alpha (TFAP2A) and RNA polymerase III (Pol III) products is associated with tumorigenesis. However, the mechanism underlying this event is not fully understood and the connection between TFAP2A and Pol III-directed transcription has not been investigated. Here, we report that TFAP2A functions as a positive factor in the regulation of Pol III-directed transcription and cell proliferation. We found TFAP2A is also required for the activation of Pol III transcription induced by the silencing of filamin A, a well-known cytoskeletal protein and an inhibitor in Pol III-dependent transcription identified previously. Using a chromatin immunoprecipitation technique, we showed TFAP2A positively modulates the assembly of Pol III transcription machinery factors at Pol III-transcribed gene loci. We found TFAP2A can activate the expression of Pol III transcription-related factors, including BRF1, GTF3C2, and c-MYC. Furthermore, we demonstrate TFAP2A enhances expression of MDM2, a negative regulator of tumor suppressor p53, and also inhibits p53 expression. Finally, we found MDM2 overexpression can rescue the inhibition of Pol III-directed transcription and cell proliferation caused by TFAP2A silencing. In summary, we identified that TFAP2A can activate Pol III-directed transcription by controlling multiple pathways, including general transcription factors, c-MYC and MDM2/p53. The findings from this study provide novel insights into the regulatory mechanisms of Pol III-dependent transcription and cancer cell proliferation.

TFAP2A downregulation mediates tumor-suppressive effect of miR-8072 in triple-negative breast cancer via inhibiting SNAI1 transcription.

BACKGROUND: Triple-negative breast cancer (TNBC) represents a highly aggressive subset of breast malignancies characterized by its challenging clinical management and unfavorable prognosis. While TFAP2A, a member of the AP-2 transcription factor family, has been implicated in maintaining the basal phenotype of breast cancer, its precise regulatory role in TNBC remains undefined. METHODS: In vitro assessments of TNBC cell growth and migratory potential were conducted using MTS, colony formation, and EdU assays. Quantitative PCR was employed to analyze mRNA expression levels, while Western blot was utilized to evaluate protein expression and phosphorylation status of AKT and ERK. The post-transcriptional regulation of TFAP2A by miR-8072 and the transcriptional activation of SNAI1 by TFAP2A were investigated through luciferase reporter assays. A xenograft mouse model was employed to assess the in vivo growth capacity of TNBC cells. RESULTS: Selective silencing of TFAP2A significantly impeded the proliferation and migration of TNBC cells, with elevated TFAP2A expression observed in breast cancer tissues. Notably, TNBC patients exhibiting heightened TFAP2A levels experienced abbreviated overall survival. Mechanistically, TFAP2A was identified as a transcriptional activator of SNAI1, a crucial regulator of epithelial-mesenchymal transition (EMT) and cellular proliferation, thereby augmenting the oncogenic properties of TFAP2A in TNBC. Moreover, miR-8072 was unveiled as a negative regulator of TFAP2A, exerting potent inhibitory effects on TNBC cell growth and migration. Importantly, the tumor-suppressive actions mediated by the miR-8072/TFAP2A axis were intricately associated with the attenuation of AKT/ERK signaling cascades and the blockade of EMT processes. CONCLUSIONS: Our findings unravel the role and underlying molecular mechanism of TFAP2A in driving tumorigenesis of TNBC. Targeting the TFAP2A/SNAI1 pathway and utilizing miR-8072 as a suppressor represent promising therapeutic strategies for treating TNBC.

AP-2α gene deregulation is associated with renal cell carcinoma patient survival.

BACKGROUND: Renal cell carcinoma (RCC), one of the most fatal urologic tumors, accounts for approximately 3% of all adult cancers and exhibits a high metastatic index at diagnosis and a high rate of relapse. Radical or partial nephrectomy is a curative option for nonmetastatic RCCs. Targeted therapy has been shown to improve the survival of patients with metastatic RCCs. However, the underlying cellular and molecular events associated with RCC pathogenesis are not well known. METHODS: To investigate the clinical role of the transcription factor activator protein (AP)-2α in RCC, methylated CpG island recovery assays and microarray analysis were employed. COBRA and RT‒qPCR assays were performed to assess AP-2α expression in RCC. RESULTS: A negative correlation was noted between AP-2α mRNA expression levels and methylation status. Multivariate analyses showed that AP-2α mRNA was a major risk factor not only for overall and disease-free survival in RCC but also for disease-free survival in clear cell RCC. CONCLUSIONS: Our results indicated that AP-2α expression was deregulated in RCC and associated with overall patient survival and disease-free survival. Such findings suggest that AP-2α might play an important role in the pathogenesis of RCC.

TFAP2C inhibits cell autophagy to alleviate myocardial ischemia/reperfusion injury by regulating miR-23a-5p/SFRP5/Wnt5a axis.

Myocardial ischemia/reperfusion (MI/R) injury contributes to severe injury for cardiomyocytes. In this study, we aimed to explore the underlying mechanism of TFAP2C on cell autophagy in MI/R injury. MTT assay measured cell viability. The cells injury was evaluated by commercial kits. IF detected the level of LC3B. Dual luciferase reporter gene assay, ChIP or RIP assay were performed to verify the interactions between crucial molecules. We found that TFAP2C and SFRP5 expression were decreased while miR-23a-5p and Wnt5a increased in AC16 cells in response to H/R condition. H/R induction led to cell injury and induced autophagy, which were reversed by TFAP2C overexpression or 3-MA treatment (an autophagy inhibitor). Mechanistically, TFAP2C suppressed miR-23a expression through binding to miR-23a promoter, and SFRP5 was a target gene of miR-23a-5p. Moreover, miR-23a-5p overexpression or rapamycin reversed the protective impacts of TFAP2C overexpression on cells injury and autophagy upon H/R condition. In conclusion, TFAP2C inhibited autophagy to improve H/R-induced cells injury by mediating miR-23a-5p/SFRP5/Wnt5a axis.

Transcription factor AP-2 gamma affects porcine early embryo development by regulating epigenetic modification.

RESEARCH QUESTION: What is the role and mechanism of action of transcription factor AP-2 gamma (TFAP2C) in porcine early embryo development? DESIGN: TFAP2C siRNA were injected into porcine oocytes, which subsequently underwent IVF. Different stages of embryos were collected for RNA sequencing, quantitative polymerase chain reaction, immunofluorescence staining to explore the affects in gene expression and epigenetic modification. Porcine fetal fibroblasts were transfected with siRNA, and cells were collected for chromatin immunoprecipitation and dual luciferase reporter assays. RESULTS: The deficiency of TFAP2C led to disorders in early embryonic development; 1208 genes were downregulated and 792 genes were upregulated in TFAP2C knockdown (TFAP2C-KD) embryos. The expression of epigenetic modification enzymes KDM5B, SETD2 were significantly elevated in the TFAP2C-KD group (P < 0.001). Meanwhile, the modification levels of H3K4me3 and H3K4me2 were significantly decreased (P = 0.0021, P = 0.0029), and H3K36me3 and DNA methylation were significantly increased in TFAP2C-KD group (P = 0.0045, P = 0.0025). DNMT1 was mainly expressed in nuclei in the TFAP2C-KD group (P = 0.0103). In addition, TFAP2C could bind to the promoter region of SETD2, and the mutation of the TFAP2C binding site resulted in increased activity of SETD2 promoter (P < 0.001). CONCLUSIONS: The knockdown of TFAP2C affects early embryonic development by regulating histone modification and DNA methylation.

TFAP2A Upregulates SKA3 to Promote Glycolysis and Reduce the Sensitivity of Lung Adenocarcinoma Cells to Cisplatin.

INTRODUCTION: Studies have shown that glycolysis metabolism affects the resistance or sensitivity of tumors to chemotherapy drugs. Emerging from recent research, a paradigm-shifting revelation has unfolded, elucidating the oncogenic nature of SKA3 within the context of lung adenocarcinoma (LUAD). Consequently, this work was designed to delve into the effects of SKA3 on glycolysis and cisplatin (CDDP) resistance in LUAD cells and to find new possibilities for individualized treatment of LUAD. METHODS: LUAD mRNA expression data from the TCGA database were procured to scrutinize the differential expression patterns of SKA3 in both tumor and normal tissues. GSEA and Pearson correlation analyses were employed to elucidate the impact of SKA3 on signaling pathways within the context of LUAD. In order to discern the upstream regulatory mechanisms, the ChEA and JASPAR databases were utilized to predict the transcription factors and binding sites associated with SKA3. qRT-PCR and Western blot were implemented to assay the mRNA and protein expression levels of SKA3 and TFAP2A. Chromatin immunoprecipitation and dual-luciferase assays were performed to solidify the binding relationship between the two. Extracellular acidification rate, glucose consumption, lactate production, and glycolysis-related proteins (HK2, GLUT1, and LDHA) were used to evaluate the level of glycolysis. Cell viability under CDDP treatment was determined utilizing the CCK-8, allowing for the calculation of IC50. The expression levels of SKA3 and TFAP2A proteins were detected by immunohistochemistry (IHC). RESULTS: SKA3 exhibited upregulation in LUAD tissues and cell lines, establishing a direct linkage with glycolysis pathway. Overexpression of SKA3 fostered glycolysis in LUAD, resulting in reduced sensitivity toward CDDP treatment. The upstream transcription factor of SKA3, TFAP2A, was also upregulated in LUAD and could promote SKA3 transcription. Overexpression of TFAP2A also fostered the glycolysis of LUAD. Rescue assays showed that TFAP2A promoted glycolysis in LUAD cells by activating SKA3, reducing the sensitivity of LUAD cells to CDDP. The IHC analysis revealed a positive correlation between high expression of SKA3 and TFAP2A and CDDP resistance. CONCLUSION: In summary, TFAP2A can transcriptionally activate SKA3, promote glycolysis in LUAD, and protect LUAD cells from CDDP treatment, indicating that targeting the TFAP2A/SKA3 axis may become a plausible and pragmatic therapeutic strategy for the clinical governance of LUAD.

TFAP2C Activates CST1 Transcription to Facilitate Breast Cancer Progression and Suppress Ferroptosis.

Cystatin SN (CST1) appears to have pro-tumor effects in breast cancer (BC) and is involved in ferroptosis; however, there is no report on the regulation of ferroptosis by CST1 for BC development. The purpose of this study is to investigate the functions and mechanisms operated by CST1 in BC development and ferroptosis. Transcription Factor Activator Protein 2γ (TFAP2C) and CST1 levels in BC tissues and estrogen receptor (ER)+ cells were quantified by RT-qPCR and western blotting. After knocking down TFAP2C and CST1 expression in MCF7 and T47D cells, the proliferation, colony formation ability, apoptosis, and cell cycle were assessed. Ferroptosis was verified by detecting glutathione peroxidase 4 (GPX4) and 4-hydroxy-2-nonenal (4HNE) levels. The kits were used to test Fe2+, reactive oxygen species, malondialdehyde, and glutathione levels, and ultrastructure of mitochondria was observed through transmission electron microscope. Dual-luciferase reporter assay and chromatin immunoprecipitation test were carried out to investigate the interaction of TFAP2C and CST1. A transplanted tumor model was established to explore the function of TFAP2C in tumorigenesis by quantifying TFAP2C, CST1, Ki67, and GPX4 levels through western blotting and immunochemistry after silencing TFAP2C. TFAP2C and CST1 were predominantly expressed in BC cells. Silencing of TFAP2C or CST1 expression suppressed ER+ BC cell proliferation, promoted apoptosis and ferroptosis, and blocked cell cycle transition from G1 phase to S phase. TFAP2C knockdown in transplanted tumors inhibited tumor growth and GPX4 level. Upregulating CST1 nullified the anti-tumor effects of TFAP2C knockdown and TFAP2C promoted CST1 expression through transcription activation. TFAP2C activates CST1 transcription to facilitate BC development and block ferroptosis.

Zebrafish anterior segment mesenchyme progenitors are defined by function of tfap2a but not sox10.

The anterior segment is a critical component of the visual system. Developing independent of the retina, the AS relies partially on cranial neural crest cells (cNCC) as its earliest progenitors. The cNCCs are thought to first adopt a periocular mesenchyme (POM) fate and subsequently target to the AS upon formation of the rudimentary retina. AS targeted POM is termed anterior segment mesenchyme (ASM). However, it remains unknown when and how the switch from cNCC to POM or POM to ASM takes place. As such, we sought to visualize the timing of these transitions and identify the regulators of this process using the zebrafish embryo model. Using two color fluorescence in situ hybridization, we tracked cNCC and ASM target gene expression from 12 to 24hpf. In doing so, we identified a tfap2a and foxC1a co-expression at 16hpf, identifying the earliest ASM to arrive at the AS. Interestingly, expression of two other key regulators of NCC, foxD3 and sox10 was not associated with early ASM. Functional analysis of tfap2a, foxD3 and sox10 revealed that tfap2a and foxD3 are both critical regulators of ASM specification and AS formation while sox10 was dispensable for either specification or development of the AS. Using genetic knockout lines, we show that in the absence of tfap2a or foxD3 function ASM cells are not specified, and subsequently the AS is malformed. Conversely, sox10 genetic mutants or CRISPR Cas9 injected embryos displayed no defects in ASM specification, migration or the AS. Lastly, using transcriptomic analysis, we show that GFP + cNCCs derived from Tg [foxD3:GFP] and Tg [foxC1b:GFP] share expression profiles consistent with ASM development whereas cNCCs isolated from Tg [sox10:GFP] exhibit expression profiles associated with vasculogenesis, muscle function and pigmentation. Taken together, we propose that the earliest stage of anterior segment mesenchyme (ASM) specification in zebrafish is approximately 16hpf and involves tfap2a/foxC1a positive cNCCs.

The AP-2 Family of Transcription Factors-Still Undervalued Regulators in Gastroenterological Disorders.

Activating enhancer-binding protein 2 (AP-2) is a family of transcription factors (TFs) that play crucial roles in regulating embryonic and oncogenic development. In addition to splice isoforms, five major family members encoded by the TFAP2A/B/C/D/E genes have been identified in humans, i.e., AP-2α/ß/γ/δ/ε. In general, the first three TFs have been studied more thoroughly than AP-2δ or AP-2ε. Currently, there is a relatively limited body of literature focusing on the AP-2 family in the context of gastroenterological research, and a comprehensive overview of the existing knowledge and recommendations for further research directions is lacking. Herein, we have collected available gastroenterological data on AP-2 TFs, discussed the latest medical applications of each family member, and proposed potential future directions. Research on AP-2 in gastrointestinal tumors has predominantly been focused on the two best-described family members, AP-2α and AP-2γ. Surprisingly, research in the past decade has highlighted the importance of AP-2ε in the drug resistance of gastric cancer (GC) and colorectal cancer (CRC). While numerous questions about gastroenterological disorders await elucidation, the available data undoubtedly open avenues for anti-cancer targeted therapy and overcoming chemotherapy resistance. In addition to gastrointestinal cancers, AP-2 family members (primarily AP-2ß and marginally AP-2γ) have been associated with other health issues such as obesity, type 2 diabetes, liver dysfunction, and pseudo-obstruction. On the other hand, AP-2δ has been poorly investigated in gastroenterological disorders, necessitating further research to delineate its role. In conclusion, despite the limited attention given to AP-2 in gastroenterology research, pivotal functions of these transcription factors have started to emerge and warrant further exploration in the future.