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The ventrolateral pallial (VLp) excitatory neurons in the claustro-amygdalar complex and piriform cortex (PIR; which forms part of the palaeocortex) form reciprocal connections with the prefrontal cortex (PFC), integrating cognitive and sensory information that results in adaptive behaviours 1 , 2 , 3 , 4 – 5 . Early-life disruptions in these circuits are linked to neuropsychiatric disorders 4 , 5 , 6 , 7 – 8 , highlighting the importance of understanding their development. Here we reveal that the transcription factors SOX4, SOX11 and TFAP2D have a pivotal role in the development, identity and PFC connectivity of these excitatory neurons. The absence of SOX4 and SOX11 in post-mitotic excitatory neurons results in a marked reduction in the size of the basolateral amygdala complex (BLC), claustrum (CLA) and PIR. These transcription factors control BLC formation through direct regulation of Tfap2d expression. Cross-species analyses, including in humans, identified conserved Tfap2d expression in developing excitatory neurons of BLC, CLA, PIR and the associated transitional areas of the frontal, insular and temporal cortex. Although the loss and haploinsufficiency of Tfap2d yield similar alterations in learned threat-response behaviours, differences emerge in the phenotypes at different Tfap2d dosages, particularly in terms of changes observed in BLC size and BLC–PFC connectivity. This underscores the importance of Tfap2d dosage in orchestrating developmental shifts in BLC–PFC connectivity and behavioural modifications that resemble symptoms of neuropsychiatric disorders. Together, these findings reveal key elements of a conserved gene regulatory network that shapes the development and function of crucial VLp excitatory neurons and their PFC connectivity and offer insights into their evolution and alterations in neuropsychiatric disorders. A conserved gene regulatory network involving SOX4 , SOX11 and TFAP2D shapes the development of excitatory neurons in ventrolateral pallium and their connectivity with the prefrontal cortex.

The transcription factor AP-2α plays a crucial role in the control of tumor development and progression, and suppresses the proliferation and migration of hepatocellular carcinoma (HCC). However, the detailed function and mechanisms of AP-2α in the pathogenesis of HCC are still elusive. In the current study, we investigated the role of AP-2α regulation in liver injury-mediated HCC development. Downregulation of Tfap2a expression was found in the livers of DEN/CCl 4 -induced fibrosis and HCC mouse model. Hepatocyte (Alb-Cre), hepatic stellate cell (HSC) (Lrat-Cre) and macrophage (LysM-Cre) specific Tfap2a knockout mice were generated, respectively. Conditional knockout of Tfap2a was able to promote hepatic steatosis in Tfap2a ΔHep and Tfap2a ΔMΦ mice, but not in Tfap2a ΔHSC mice fed with normal chow. Tfap2a ΔHep and Tfap2a ΔMΦ mice treated with DEN/CCl 4 for 6 months increased tumor burden compared to Tfap2a flox controls. Tfap2a-deleted macrophages or hepatocytes could enhance lipid droplet (LD) accumulation in hepatocytes. Mechanistically, AP-2α binds to the promoter regions of SREBP1/ACC/FASN and inhibits hepatic lipid de novo synthesis. Deletion of Tfap2a in macrophages enhances polarization of M1 macrophages with increased iNOS expression but decreased CD206 expression, which resulted in increased pro-inflammatory cytokines and decreased anti-inflammatory factors, especially the hepatoprotective factor IL-10. The m6A modification writer WTAP could reduce the mRNA stability of AP-2α in a reader YTHDC1-dependent manner, whereas knockdown of WTAP or YTHDC1 enhances AP-2α expression and decreases lipid accumulation in HCC cells. Clinically, AP-2α expression negatively correlates with the expression of FASN, WTAP, YTHDC1 and the development of liver disease. Taken together, hepatocyte- or macrophage-specific deletion of Tfap2a promotes hepatic steatosis, fibrosis, and the development of HCC. These results suggest that AP-2α has been identified as a novel therapeutic target in fibrosis and inflammation-related HCC, exerting anti-lipogenesis, anti-inflammatory, and anti-tumor multi-roles.

Maintenance and maturation of primordial germ cells is controlled by complex genetic and epigenetic cascades, and disturbances in this network lead to either infertility or malignant aberration. Transcription factor TFAP2C has been described to be essential for primordial germ cell maintenance and to be upregulated in several human germ cell cancers. Using global gene expression profiling, we identified genes deregulated upon loss of Tfap2c in embryonic stem cells and primordial germ cell-like cells. We show that loss of Tfap2c affects many aspects of the genetic network regulating germ cell biology, such as downregulation of maturation markers and induction of markers indicative for somatic differentiation, cell cycle, epigenetic remodeling and pluripotency. Chromatin-immunoprecipitation analyses demonstrated binding of TFAP2C to regulatory regions of deregulated genes (Sfrp1, Dmrt1, Nanos3, c-Kit, Cdk6, Cdkn1a, Fgf4, Klf4, Dnmt3b and Dnmt3l) suggesting that these genes are direct transcriptional targets of TFAP2C in primordial germ cells. Since Tfap2c deficient primordial germ cell-like cells display cancer related deregulations in epigenetic remodeling, cell cycle and pluripotency control, the Tfap2c-knockout allele was bred onto 129S2/Sv genetic background. There, mice heterozygous for Tfap2c develop with high incidence germ cell cancer resembling human pediatric germ cell tumors. Precursor lesions can be observed as early as E16.5 in developing testes displaying persisting expression of pluripotency markers. We further demonstrate that mice with a heterozygous deletion of the TFAP2C target gene Nanos3 are also prone to develop teratomas. These data highlight TFAP2C as a critical and dose-sensitive regulator of germ cell fate.

The transcription factor activating protein two gamma (AP2γ) is an important regulator of neurogenesis both during embryonic development as well as in the postnatal brain, but its role for neurophysiology and behavior at distinct postnatal periods is still unclear. In this work, we explored the neurogenic, behavioral, and functional impact of a constitutive and heterozygous AP2γ deletion in mice from early postnatal development until adulthood. AP2γ deficiency promotes downregulation of hippocampal glutamatergic neurogenesis, altering the ontogeny of emotional and memory behaviors associated with hippocampus formation. The impairments induced by AP2γ constitutive deletion since early development leads to an anxious-like phenotype and memory impairments as early as the juvenile phase. These behavioral impairments either persist from the juvenile phase to adulthood or emerge in adult mice with deficits in behavioral flexibility and object location recognition. Collectively, we observed a progressive and cumulative impact of constitutive AP2γ deficiency on the hippocampal glutamatergic neurogenic process, as well as alterations on limbic-cortical connectivity, together with functional behavioral impairments. The results herein presented demonstrate the modulatory role exerted by the AP2γ transcription factor and the relevance of hippocampal neurogenesis in the development of emotional states and memory processes.

Introduction The transcription factor activating enhancer binding protein 2 epsilon (AP-2ε) was recently shown to be expressed during chondrogenesis as well as in articular chondrocytes of humans and mice. Furthermore, expression of AP-2ε was found to be upregulated in affected cartilage of patients with osteoarthritis (OA). Despite these findings, adult mice deficient for AP-2ε ( Tfap2e −/− ) do not exhibit an obviously abnormal cartilaginous phenotype. We therefore analyzed embryogenesis of Tfap2e −/− mice to elucidate potential transient abnormalities that provide information on the influence of AP-2ε on skeletal development. In a second part, we aimed to define potential influences of AP-2ε on articular cartilage function and gene expression, as well as on OA progression, in adult mice. Methods Murine embryonic development was accessed via in situ hybridization, measurement of skeletal parameters and micromass differentiation of mesenchymal cells. To reveal discrepancies in articular cartilage of adult wild-type (WT) and Tfap2e −/− mice, light and electron microscopy, in vitro culture of cartilage explants, and quantification of gene expression via real-time PCR were performed. OA was induced via surgical destabilization of the medial meniscus in both genotypes, and disease progression was monitored on histological and molecular levels. Results Only minor differences between WT and embryos deficient for AP-2ε were observed, suggesting that redundancy mechanisms effectively compensate for the loss of AP-2ε during skeletal development. Surprisingly, though, we found matrix metalloproteinase 13 (Mmp13), a major mediator of cartilage destruction, to be significantly upregulated in articular cartilage of adult Tfap2e −/− mice. This finding was further confirmed by increased Mmp13 activity and extracellular matrix degradation in Tfap2e −/− cartilage explants. OA progression was significantly enhanced in the Tfap2e −/− mice, which provided evidence for in vivo relevance. This finding is most likely attributable to the increased basal Mmp13 expression level in Tfap2e −/− articular chondrocytes that results in a significantly higher total Mmp13 expression rate during OA as compared with the WT. Conclusions We reveal a novel role of AP-2ε in the regulation of gene expression in articular chondrocytes, as well as in OA development, through modulation of Mmp13 expression and activity.

Background AP-2δ is the most divergent member of the Activating Protein-2 (TFAP2) family of transcription factors. AP-2δ is restricted to specific regions of the CNS, including a subset of ganglion cells in the retina. Retinal ganglion cells (RGCs), the only output neurons of the retina, are responsible for transmitting the visual signal to the brain. Results AP-2δ knockout results in loss of Brn3c ( Pou4f3 ) expression in AP-2δ -positive RGCs. While AP-2δ-/- mice have morphologically normal retinas at birth, there is a significant reduction in retinal ganglion cell numbers by P21, after eye opening. Chromatin immunoprecipitation indicates that Brn3c is a target of AP-2δ in the retina. Using fluorochrome-conjugated cholera toxin subunit B to trace ganglion cell axons from the eye to the major visual pathways in the brain, we found 87 % and 32 % decreases in ipsilateral and contralateral projections, respectively, to the superior colliculus in AP-2δ-/- mice. In agreement with anatomical data, visually evoked responses recorded from the brain confirmed that retinal outputs to the brain are compromised. Conclusions AP-2δ is important for the maintenance of ganglion cell numbers in the retina. Loss of AP-2δ alters retinal axonal projections to visual centers of the brain, with ipsilaterial projections to the superior colliculus being the most dramatically affected. Our results have important implications for integration of the visual signal at the superior colliculus.

Ap-2 transcription factors comprise a family of 5 closely related sequence-specific DNA binding proteins that play pivotal and non-redundant roles in embryonic organogenesis. To investigate the function of Ap-2δ, wδe analyzed its expression during embryogenesis and generated Ap-2δ-deficient mice. In line with the specific expression pattern of Ap-2δ in the mesencephalic tectum and the dorsal midbrain, Ap-2δ-deficient mice failed to maintain the colliculus inferior, a derivative of the dorsal midbrain, as a consequence of increased apoptotic cell death. To identify specific Ap-2δ target genes in cells of the developing dorsal midbrain, we performed whole genome analysis of cDNA expression levels. This approach identified a set of 12 putative target genes being expressed in the developing midbrain, including the transcription factors Pitx2, Mef2c, Bhlhb4 and Pou4f3. Using chromatin immunoprecipitation (CHIP) we showed that some of these genes are direct targets of Ap-2δ. Consistently, we demonstrate that Ap-2δ occupies and activates the Pou4f3 and Bhlhb4 promoters. In addition, known Pou4f3 target genes were downregulated in the posterior midbrain of Ap-2δ-deficient mice. Despite the absence of a central part of the auditory pathway, the presence of neuronal responses to sounds in the neocortex of Ap-2δ-deficient mice indicates that auditory information from the brainstem still reaches the neocortex. In summary, our data define Ap-2δ as an important transcription factor, specifying gene expression patterns required for the development of the posterior midbrain.

Numerous gene loci are related to single measures of body weight and shape. We investigated if 55 SNPs previously associated with BMI or waist measures, modify the effects of fat intake on weight loss and waist reduction under energy restriction. Randomized controlled trial of 771 obese adults. ( ISRCTN25867281.) One SNP was selected for replication in another weight loss intervention study of 934 obese adults. The original trial was a 10-week 600 kcal/d energy-deficient diet with energy percentage from fat (fat%) in range of 20-25 or 40-45. The replication study used an 8-weeks diet of 880 kcal/d and 20 fat%; change in fat% intake was used for estimation of interaction effects. The main outcomes were intervention weight loss and waist reduction. In the trial, mean change in fat% intake was -12/+4 in the low/high-fat groups. In the replication study, it was -23/-12 among those reducing fat% more/less than the median. TFAP2B-rs987237 genotype AA was associated with 1.0 kg (95% CI, 0.4; 1.6) greater weight loss on the low-fat, and GG genotype with 2.6 kg (1.1; 4.1) greater weight loss on the high-fat (interaction p-value; p = 0.00007). The replication study showed a similar (non-significant) interaction pattern. Waist reduction results generally were similar. Study-strengths include (i) the discovery study randomised trial design combined with the replication opportunity (ii) the strict dietary intake control in both studies (iii) the large sample sizes of both studies. Limitations are (i) the low minor allele frequency of the TFAP2B polymorphism, making it hard to investigate non-additive genetic effects (ii) the different interventions preventing identical replication-discovery study designs (iii) some missing data for non-completers and dietary intake. No adverse effects/outcomes or side-effects were observed. Under energy restriction, TFAP2B may modify the effect of dietary fat intake on weight loss and waist reduction.

Gastric Squamous Cell Carcinoma (GSCC) is a rare but aggressive subtype of gastric cancer with unique histopathology, whose etiology remains poorly understood. Here, we perform genomics analyses of twenty GSCC samples and find that epigenetic regulation genes are among the most frequently mutated genes, including Enhancer of zeste homolog 2 ( EZH2 ). Ezh2 loss induces squamous feature both in gastric organoids in vitro and in vivo mouse model. Ezh2 deficiency, together with Trp53 and Pten loss, both of which are also frequently mutated in GSCC, give rise to full-blown GSCC in mice. Mechanistically, we find that Ezh2 could repress the expression of Transcription factor AP-2 gamma ( Tfap2c ), a transcription factor with the ability to initiate epidermal squamous differentiation, through H3K27 methylation. Disruption of Tfap2c reduces the squamous characteristics of the Ezh2 loss-driven GSCC and reverses its resistance to chemo treatment. Our findings elucidate key molecular mechanisms underlying GSCC pathogenesis and identify potential therapeutic targets for this aggressive malignancy. Gastric Squamous Cell Carcinoma (GSCC) is a rare subtype of gastric cancer with unknown etiology. Here, the authors identify frequent mutations in epigenetic regulation genes including EZH2 in twenty GSCC patient samples, and demonstrate that EZH2 loss, along with TP53 and PTEN loss, leads to GSCC in mouse models.

We have previously demonstrated that the transition of melanoma to the metastatic phenotype is associated with a loss of expression of the transcription factor AP-2. To further investigate the role of AP-2 in the progression of human melanoma, we attempted to inactivate AP-2 in primary cutaneous SB-2 melanoma cells by using a dominant-negative AP-2, or AP-2B, gene. AP-2B is an alternatively spliced AP-2 variant capable of inhibiting AP-2 trans-activator function. Stable transfection of primary cutaneous melanoma SB-2 cells with the dominant-negative AP-2B gene was confirmed by RT--PCR and Northern blot analyses. Electromobility shift assay using nuclear extracts from these cell lines demonstrated decreased functional binding of AP-2B-transfected cells to the AP-2 consensus binding sequence compared with neo-transfected controls. In addition, CAT activity driven by a construct containing the AP-2 consensus binding sequence was downregulated in the AP-2B transfected cells, indicating AP-2 activity was quenched in the transfected cells. Orthotopic (subcutaneous) injection of the dominant-negative (AP-2B)-transfected cell lines into nude mice increased their tumorigenicity compared to control neo-transfected cells. The AP-2B-transfected cells displayed an increase in MMP-2 expression (by Northern blot) and MMP-2 activity (by zymography), which resulted in an increase in invasiveness through Matrigel-coated filters. The AP-2B-transfected tumors also displayed an increase in MMP-2 expression, microvessel density, and angiogenesis in vivo. These results demonstrate that inactivation of AP-2 contributes to the progression of melanoma, at least partially via deregulation of the MMP-2 gene.