GATA-1 Protein Research Articles

In utero morphological and functional properties of bovine trophoblastic vesicles.

In many mammals, including ruminants, pregnancy requires pregnancy recognition signaling molecules secreted by the conceptus; however, the mechanism underlying pregnancy establishment in cattle remains unknown. Trophoblastic vesicles (TVs) are artificially produced from the extraembryonic tissues of the elongating conceptus and may be useful tools for understanding conception. This study investigated the morphological and functional properties of TVs in comparison to those of intact conceptuses. TVs were prepared from the extraembryonic tissues of conceptuses collected 14 days after artificial insemination (AI), cryopreserved immediately after dissection, and cultured after thawing for subsequent transplantation into the uterus. The transferred TVs were collected 7 days after transplantation and compared with extraembryonic tissue samples collected from conceptuses at 21 days post-AI. The recovered TVs were 40 times longer than those of their pre-transplant counterparts. Microscopic evaluation revealed that their membrane structures consisted of trophoblast and hypoblast layers. The expression patterns of the cell differentiation markers, CDX2, SOX2, and GATA6, and interferon tau (IFNT) protein expression levels in the TVs were similar to those in control extraembryonic tissue samples. These findings suggest that TVs are capable of morphological elongation and maintain IFNT production in a similar way as original trophoblasts.

GATA2 deficiency syndrome: A compensatory mechanism gone awry?

In their paper, using zebrafish models, Gioacchino etal. have demonstrated the GATA2 haploinsufficiency, the genetic hallmark of GATA2 deficiency syndrome, promotes erythroid and myeloid cytopenia, and have discovered a self-regulatory mechanism to compensate GATA2 levels and protein function. Commentary on: Gioacchino etal. GATA2 heterozygosity causes an epigenetic feedback mechanism resulting in myeloid and erythroid dysplasia. Br J Haematol 2024;205:580-593.

FABP4 Is an Indispensable Factor for Regulating Cellular Metabolic Functions of the Human Retinal Choroid.

The purpose of the current study was to elucidate the physiological roles of intraocularly present fatty acid-binding protein 4 (FABP4). Using four representative intraocular tissue-derived cell types, including human non-pigmented ciliary epithelium (HNPCE) cells, retinoblastoma (RB) cells, adult retinal pigment epithelial19 (ARPE19) cells and human ocular choroidal fibroblast (HOCF) cells, the intraocular origins of FABP4 were determined by qPCR analysis, and the intracellular functions of FABP4 were investigated by seahorse cellular metabolic measurements and RNA sequencing analysis using a specific inhibitor for FABP4, BMS309403. Among these four different cell types, FABP4 was exclusively expressed in HOCF cells. In HOCF cells, both mitochondrial and glycolytic functions were significantly decreased to trace levels by BMS309403 in a dose-dependent manner. In the RNA sequencing analysis, 67 substantially up-regulated and 94 significantly down-regulated differentially expressed genes (DEGs) were identified in HOCF cells treated with BMS309403 and those not treated with BMS309403. The results of Gene Ontology enrichment analysis and ingenuity pathway analysis (IPA) revealed that the DEGs were most likely involved in G-alpha (i) signaling, cAMP-response element-binding protein (CREB) signaling in neurons, the S100 family signaling pathway, visual phototransduction and adrenergic receptor signaling. Furthermore, upstream analysis using IPA suggested that NKX2-1 (thyroid transcription factor1), HOXA10 (homeobox A10), GATA2 (gata2 protein), and CCAAT enhancer-binding protein A (CEBPA) were upstream regulators and that NKX homeobox-1 (NKX2-1), SFRP1 (Secreted frizzled-related protein 1) and TREM2 (triggering receptor expressed on myeloid cells 2) were causal network master regulators. The findings in this study suggest that intraocularly present FABP4 originates from the ocular choroid and may be a critical regulator for the cellular homeostasis of non-adipocyte HOCF cells.

PML::RARA and GATA2 proteins interact via DNA templates to induce aberrant self-renewal in mouse and human hematopoietic cells

The underlying mechanism(s) by which the PML::RARA fusion protein initiates acute promyelocytic leukemia is not yet clear. We defined the genomic binding sites of PML::RARA in primary mouse and human hematopoietic progenitor cells with V5-tagged PML::RARA, using anti-V5-PML::RARA chromatin immunoprecipitation sequencing and CUT&RUN approaches. Most genomic PML::RARA binding sites were found in regions that were already chromatin-accessible (defined by ATAC-seq) in unmanipulated, wild-type promyelocytes, suggesting that these regions are "open" prior to PML::RARA expression. We found that GATA binding motifs, and the direct binding of the chromatin "pioneering factor" GATA2, were significantly enriched near PML::RARA binding sites. Proximity labeling studies revealed that PML::RARA interacts with ~250 proteins in primary mouse hematopoietic cells; GATA2 and 33 others require PML::RARA binding to DNA for the interaction to occur, suggesting that binding to their cognate DNA target motifs may stabilize their interactions. In the absence of PML::RARA, Gata2 overexpression induces many of the same epigenetic and transcriptional changes as PML::RARA. These findings suggested that PML::RARA may indirectly initiate its transcriptional program by activating Gata2 expression: Indeed, we demonstrated that inactivation of Gata2 prior to PML::RARA expression prevented its ability to induce self-renewal. These data suggested that GATA2 binding creates accessible chromatin regions enriched for both GATA and Retinoic Acid Receptor Element motifs, where GATA2 and PML::RARA can potentially bind and interact with each other. In turn, PML::RARA binding to DNA promotes a feed-forward transcriptional program by positively regulating Gata2 expression. Gata2 may therefore be required for PML::RARA to establish its transcriptional program.

Unraveling Hypothalamus-Pituitary dysregulation: Hypergonadotropism in F1 progeny due to prenatal exposure to hexavalent chromium.

The endocrine disruptor hexavalent chromium [Cr(VI)] is a proven reproductive toxicant. We recently demonstrated that prenatal Cr(VI) exposure causes testicular resistance to gonadotropins, resulting in hypergonadotropic hypoandrogenism in F1 rats. However, the mechanism driving hypergonadotropism in F1 rats exposed to Cr(VI) prenatally remains an enigma. Therefore, we hypothesized that 'Prenatal Cr(VI) exposure may disrupt steroid hormones-mediated negative feedback regulation of the hypothalamic GnRH, and its receptor in the pituitary of F1 rats, leading to hypergonadotropism.' We administered potassium dichromate (50, 100, or 200 mg/L) to pregnant rats through drinking water between days 9 and 14, and their male F1 offspring were euthanized at 60 days of age. Prenatal Cr(VI) exposure in F1 rats resulted in the accumulation of Cr in the hypothalamus and pituitary. Western blot detected decreased hypothalamic GnRH, Kisspeptin1, and its receptor GPR54, along with diminished ERα, AR, aromatase, and 5α reductase, and GnRH regulatory transcription factors Pit-1 and GATA-4 proteins. Immunohistochemical studies revealed increased immunopositivity of GnRH receptor, AR, 5α reductase, ERα, ERβ, and aromatase proteins in the pituitary, whereas decreased Kisspeptin1, GPR54, and inhibin β. Our findings imply that Cr(VI) exposure during the prenatal period disrupts the hypothalamic Kisspeptin-GPR54-Pit-1/GATA4-GnRH network, boosting the pituitary GnRH receptor. We conclude that prenatal exposure to Cr(VI) alters GnRH expression in the hypothalamus and its receptor in the pituitary of F1 progeny through interfering with the negative feedback effect of androgens and estrogens.

Switching of hypertrophic signalling towards enhanced cardiomyocyte identity and maturity by a GATA4-targeted compound.

The prevalence of heart failure is constantly increasing, and the prognosis of patients remains poor. New treatment strategies to preserve cardiac function and limit cardiac hypertrophy are therefore urgently needed. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are increasingly used as an experimental platform for cardiac in vitro studies. However, in contrast to adult cardiomyocytes, hiPSC-CMs display immature morphology, contractility, gene expression and metabolism and hence express a naive phenotype that resembles more of a foetal cardiomyocyte. A library of 14 novel compounds was synthesized in-house and screened for GATA4-NKX2-5 reporter activity and cellular toxicity. The most potent compound, 3i-1262, along with previously reported GATA4-acting compounds, were selected to investigate their effects on hypertrophy induced by endothelin-1 or mechanical stretch. Morphological changes and protein expression were characterized using immunofluorescence staining and high-content analysis. Changes in gene expression were studied using qPCR and RNA sequencing. The prototype compound 3i-1262 inhibited GATA4-NKX2-5 synergy in a luciferase reporter assay. Additionally, the isoxazole compound 3i-1262 inhibited the hypertrophy biomarker B-type natriuretic peptide (BNP) by reducing BNP promoter activity and proBNP expression in neonatal rat ventricular myocytes and hiPSC-CMs, respectively. Treatment with 3i-1262 increased metabolic activity and cardiac troponin T expression in hiPSC-CMs without affecting GATA4 protein levels. RNA sequencing analysis revealed that 3i-1262 induces gene expression related to metabolic activity and cell cycle exit, indicating a change in the identity and maturity status of hiPSC-CMs. The biological processes that were enriched in upregulated genes in response to 3i-1262 were downregulated in response to mechanical stretch, and conversely, the downregulated processes in response to 3i-1262 were upregulated in response to mechanical stretch. There is currently a lack of systematic understanding of the molecular modulation and control of hiPSC-CM maturation. In this study, we demonstrated that the GATA4-interfering compound 3i-1262 reorganizes the cardiac transcription factor network and converts hypertrophic signalling towards enhanced cardiomyocyte identity and maturity. This conceptually unique approach provides a novel structural scaffold for further development as a modality to promote cardiomyocyte specification and maturity.

Unravelling the Mechanism behind Ineffective Erythropoiesis in Sickle Cell Disease: The Role of GATA-1

Background & Objectives: Ineffective erythropoiesis (IE) is an important factor in many types of anemias, including beta-thalassemia. Recently, a study by El Hoss et al provided compelling evidence for IE being an important part of the pathophysiology of sickle cell anemia (SCA) (PMID: 32855279). Furthermore, we developed a clinical index to measure IE and showed that patients with the SS genotype, but not SC, had increased IE compared to healthy donors (HD) (PMID: 34670360). However, the molecular mechanisms of IE in SCA, its relationship to disease heterogeneity and its potential as a therapeutic target, remain unknown. Importantly, GATA1, an essential erythroid transcription factor known to be downregulated in haematological conditions presenting with IE, has not been previously investigated in SCA. Thus, the aim of this project is to investigate the molecular basis of IE in SCA by focusing on GATA1 functions in erythropoiesis. Methods: HUDEP-2 cells, gene-edited sickle HUDEP-2 (SS HUDEP-2) (PMID: 32405513) cells and CD34+ cells isolated from individuals with HbSS and healthy donors, were differentiated ex vivo using a two-phase culture and (i) erythroid differentiation kinetics, (ii) markers of oxidative stress, (iii) GATA1 expression and (iv) antioxidant response factors NRF2, FOXO3 and heme-oxygenase 1 (HO-1) were assayed every other day during phase 2. IE was also studied in SS Berkeley transgenic mouse (PMID: 16166585). Both the spleen and the bone marrow were investigated in AA, AS and SS mice. Results: No significant differences were observed in the differentiation kinetics and in levels of oxidative stress in in vitro differentiated HUDEP-2 and SS HUDEP-2 cells. Moreover, GATA1 levels were similar in both cases. Importantly, ex vivo differentiation of human SS CD34+ cells showed a striking delay accompanied by high oxidative stress and a decrease in GATA1 protein levels (Figure 1) compared to normal controls. We also found a significant decrease in FOXO3, NRF2 and HO-1 levels in SS erythroblasts compared to healthy donor erythroblasts. IE was evident in SS mice compared to AA and AS controls. SS mice presented with higher levels of reactive oxygen species (ROS) in both the bone marrow and the spleen tissue. Histological studies showed that the SS Berkley mouse has a very congested bone marrow with a disorganized architecture. Moreover, we showed a significant decrease in GATA1 protein in SS spleen and bone marrow erythroid cells. Conclusion: Using ex vivo differentiation of primary SS cells and an in vivo mouse model for SCA, we show for the first time that aberrant GATA-1 levels play a key role during IE in SCA. During SS erythropoiesis, a significant reduction in the protein levels of the GATA1 erythroid master transcription factor and of FOXO3 and NF-E2, important transcriptional regulators of the oxidative stress response occur. These same changes were not seen in SS HUDEP-2 cells, suggesting that abnormalities of the bone marrow niche are central to abnormal erythropoiesis in SCA. Modification of the bone marrow niche and manipulation of GATA-1 levels may be important therapeutic tools in SCA.

Integrative Genome and Transcriptome Sequencing Analysis Indicates Genetic and Epigenetic Dysregulation in DS-AML

Down Syndrome related AML is driven by GATA1 alterations in patients with trisomy 21. Using exome or targeted sequencing, prior studies identified GATA1 alterations in ~80-90% of patients. We performed whole genome sequencing coupled with whole transcriptome sequencing on 207 cases to study the genomic basis of Down Syndrome AML. We detected GATA1 alterations in 96.1% of cases, with additional structural rearrangements in GATA1 in 15% of cases that may have been missed in prior studies. For GATA1, although substitutions and small indels occur nearly uniformly across exon 2, we observed that internal tandem duplications (ITDs) are significantly enriched in the second half of exon 2, suggesting a specific mutational mechanism for these cases. We also detected exon 3 (instead of exon 2) deletion in one case, where the resultant truncated GATA1 protein is different from the commonly recognized sGATA1. Our study further revealed that mutations in genes mediating JAK-STAT signaling (JAK1/JAK2/JAK3), RAS pathway (KRAS/NRAS/NF1), Cohesin complex (STAG2/CTCF/RAD21/SMC3), as well as MBNL1, KANSL1, IRX1, and NFIA. By integrating the genome with transcriptome sequencing data, we discovered that GATA1 exon 2 skipping to be a significant event in DS-AML. Although exon 2 is nearly completely skipped in cases with exon 2 deletion or splice site alterations, significant exon 2 skipping is also observed in cases where the alteration is small and is in the middle of exon 2. Further, exon 2 skipping is also observed in cases wither the alteration is a single base substitution that results in stop codon in the middle of exon 2 (therefore splicing is unlikely affected by these alterations in such cases). Based on this observation, we propose a hybrid genetic-epigenetic model on the development of Down Syndrome AML. In DS-AML, GATA1 exon 2 skipping during transcription/splicing might be a developmentally (epigenetically) regulated event in early fetal development that is destined to be silenced in the postnatal period that results in activation of the canonical long GATA1. This epigenetic silencing of sGATA1 is overridden by secondary genetic events, thus maintaining sGATA1 as the predominant GATA1 protein. Notably, the sGATA1 have variable isoforms as a result of exon 2 or exon 3 loss. In summary, our integrated whole genome and transcriptome approach has resulted in discovery of novel and high-prevalence structural alterations in GATA1 and potentially novel genes involved in pathogenesis of DS-AML. Our integrated analysis provided evidence on the epigenetic/developmental regulation of GATA1 exon 2 skipping via alterative splicing in the context of trisomy 21 that warrants further investigation.

GATA1 Target Gene CSF2RB Is Functionally Coupled to MPL and Marks a TPO-Dependent Preleukemic TAM Cell Population Sustained By the Fetal Liver but Not Bone Marrow

Paediatric cancers differ from adult cancers on the basis of their genetics and biology. Understanding these differences can identify factors important in oncogenesis during development. One exemplar are the genetically linked myeloid pre-leukemic and leukemic disorders in newborns and children with Trisomy 21 (T21) or Down syndrome (DS). DS children have a 400-fold increased risk of developing myeloid leukemia (ML-DS) in early life. ML-DS is preceded by a fetal/neonatal pre-leukemic phase known as transient abnormal myelopoiesis (TAM), when T21 hemopoietic cells acquire mutations in the GATA1 gene. These mutations produce an N-terminal truncated GATA1 protein (GATA1s). Remarkably, the proliferative effect exerted by T21 and GATA1s is developmentally restricted. As hemopoiesis shifts from fetal liver to new-born bone marrow, TAM usually spontaneously regresses. The biological basis for the requirement of a fetal liver environment for TAM cells and their failure to thrive in the bone marrow is unknown. However, a clue is that TAM cells can proliferate in bone marrow if they acquire oncogenic mutations, typically in genes of the JAK-STAT signalling pathway. These mutations transform the TAM clone to an ML-DS clone. To address the question of why TAM cells survive only in a fetal liver environment, we performed scRNA sequencing, coupled with genotyping from 3 primary TAM samples. 4 T21 and 3 disomic cord blood samples were used as controls (Fig1A). We identified a marked expansion of mutant TAM GATA1s cells, compared to controls, at the earliest GATA1-expressing progenitor stages (Fig1A). TAM GATA1s cells displayed transcriptional upregulation of the PI3K/AKT/mTOR, TNFA/NFκB and JAK/STAT pathways and enhanced STAT3 regulon activity when compared to controls (Fig1A). We hypothesized that aberrant cytokine receptor activation leading to increased STAT3 activity is essential for GATA1s cell proliferation. Differential gene expression between TAM GATA1s cells and disomic cells, pointed to CSF2RB, a cytokine receptor that directly activates the JAK-STAT signalling pathway (Fig1A). Next, we demonstrated that CSF2RB is overexpressed at the protein level in TAM and marks 80% of CD34 + cells compared to 5% CD34+ control cells. Using CUT&TAG we confirmed binding of GATA1s and GATA2 at two GATA sites in the CSF2RB locus in CMK cells (Fig 1A). CRISPR-Cas9 disruption of either GATA2, or the -12kb GATA motif led to downregulation of CSF2RB protein (Fig1A). We are testing if GATA1 represses CSF2RB and whether GATA1s fails to repress CSF2RB, allowing sustained abnormal CSF2RB expression in TAM. CSF2RB gene knockout in GATA1s cells leads to cell death. Taken together, CSF2RB is a direct GATA target gene and abnormal sustained, CSF2RB expression in TAM cells is required for GATA1s cell survival. Classically, CSF2RB partners with the α-chain of either IL3, IL5 or GMCSF receptors. Interestingly, none of the α-chains are expressed at the protein or RNA level in TAM CSF2RB+ cells, suggesting that CSF2RB might partner with another cytokine receptor. We nominated MPL, the thrombopoietin (TPO) receptor as a new candidate binding partner of CSF2RB for the following reasons: (i) we documented co-expression of MPL with CSF2RB at the RNA and protein level in TAM cells. (ii) we confirmed functional coupling between CSF2RB and MPL in Ba/F3 and TF-1 cells, where at equivalent MPL levels, TPO signalling via the JAK-STAT pathway is enhanced by CSF2RB. This effect is stronger at high TPO levels. (iii) A mutation in CSFR2RB (A455D) that we described in ML-DSrequires interaction with human MPL to induce autonomous growth of cytokine-dependent hematopoietic cells. Notably, direct interaction between MPL and CSF2RB A455D is detected by BRET assays. We hypothesize that high levels of fetal liver derived TPO sustain TAM proliferation because of the functional coupling between MPL and CSF2RB (Fig1B). This proliferation signal is lost as cells migrate to the low TPO bone marrow environment. Further work will assess TPO concentration in DS fetal liver and whether TAM cells display increased proliferation in response to varying TPO doses. In summary, we propose a model whereby reduced TPO levels experienced by TAM cells as they migrate from fetal liver to bone marrow creates selective pressure for acquisition of secondary mutations that permit TAM cells to proliferate independently of the high TPO environment of the fetal liver (Fig1B).

Transcription Factor GATA2 Is Inevitable for the Survival and Proper Differentiation of Thymic Multipotent Progenitor Cells By Gene Expression Orchestration

Proper differentiation of T cells in the thymus is inevitable for the establishment of acquired immunity. Lymphoid-primed multipotent progenitors (LMPPs) emigrate from the bone marrow (BM) to the thymus for becoming earliest T cell progenitors, so-called early T cell progenitors (ETPs). Previous studies have shown that ETPs retain not only T cell but also innate immune cell (i.e., myeloid cells) differentiation potentials. Therefore, ETPs might be the bifurcation point of innate and adaptive immunity in thymus. However, still little is known about the mechanism by which the differentiation fates are determined in ETPs and the cellular heterogeneity in ETP subset. Since transcription factors that possess important roles in hematopoietic stem and progenitor cells (HSPCs) may play significant roles in the early differentiation of T cells as legacy stem cell genes, we sought to investigate the roles for GATA2, which is known to regulate the HSPC maintenance and myeloid differentiation, in ETPs. First, we revealed the GATA2 expression is preserved in ETPs and sharply disappear with their differentiation (GATA2 expressions were almost undetectable from double-negative 2 cells even by qPCR). To reveal the roles for GATA2 in T cell hematopoiesis, we analyzed Gata2 fl/fl; Mx1-Cre mice in which GATA2 was deletable in hematopoietic cells by polyI:C administration ( Gata2 KO). Gata2 KO mice showed a smaller thymus and a lower number of thymic T cells, including ETPs and double-positive (DP; CD4 +CD8 +) cells, than control. To rule out contributions of potential GATA2 deletions in non-hematopoietic cells, CD45.1 + wild-type unfractionated BM cells were transplanted into Gata2 KO or control mice. There were no particular differences in T cell hematopoiesis from CD45.1 + donor cells between them, supporting the notion that hematopoietic cell intrinsic GATA2 are inevitable for the proper T cell hematopoiesis. To further reveal the roles for GATA2 in ETPs, we performed global transcriptomic analysis of ETPs (RNA-seq; Gata2 KO vs control). Gene set enrichment analysis (GSEA) revealed that signatures associated with cell cycle regulation, hematopoietic progenitor cells and myeloid cells were down-regulated in Gata2 KO ETPs, suggesting that GATA2 is involved in the survival and myeloid differentiation potentials in ETPs. By taking the advantage of novel GATA2 reporter mice (GATA2-VENUS mice) in which GATA2 protein levels are detectable by flow cytometry, we revealed that the ETP fraction contained a mixture of cells with high or low GATA2 expression. To be noted, the protein expression intensity of GATA2 in GATA2-high ETPs was almost equivalent to that of LMPPs. These observations suggest that GATA2-high ETPs might be a thymic multipotent progenitors (T-MPPs), the earliest thymic progenitors in which T or myeloid cell differentiation commitment is defined. To elucidate the mechanism by which GATA2 regulates the survival and differentiation of T-MPPs, we integrated publicly available chromatin immunoprecipitation followed by sequencing data targeting GATA2 (GATA2 ChIP-seq) and our ETP RNA-seq data. We found several key genes in HSPCs maintenance (i.e. Lyl1) or myeloid differentiation (i.e. Itga2b) as potential targets of GATA2. Furthermore, we sought to reveal the effect of GATA2 deletion in progenitor cells to their progenies. To this end, we performed RNA-seq of DP cells ( Gata2 KO vs control). GSEA revealed that cell cycle related gene signature was repressed in Gata2 KO DP cells compared to control. To be noted, in CD4-Cre dependent GATA2 deletion model ( Gata2 fl/fl:CD4-Cre mice), there were almost no particular cell number and transcriptomic differences, which was also analyzed by RNA-seq, in DP cells compared to control. These results suggest that GATA2 in GATA2-high ETPs, but not in DP cells, may affect the feature of DP cells, potentially by epigenetic memory. Collectively, this study revealed that GATA2 contributes to T cell hematopoiesis. GATA2 expression was maintained in a part of the ETP subset (GATA2-high ETPs) which might be equivalent to T-MPPs. GATA2 may affect the differentiation trajectory and function from GATA2-high ETPs to their progenies. Further study of this mechanism will help us to understand how the acquired and innate immune bifurcation is defined, which might pave the way to overcome T cell development related disorders, such as T-cell/myeloid mixed-phenotype acute leukemia.

Mechanisms of PML::Rara and GATA2 Protein Interactions in Hematopoietic Cells

Despite excellent outcomes for Acute Promyelocytic Leukemia (APL) patients with combined ATRA and Arsenic Trioxide therapy, the underlying molecular mechanisms by which the PML::RARA fusion oncoprotein initiates APL are not yet clear. We recently found that the ability of PML::RARA to initiate aberrant serial replating (a surrogate for self-renewal) is dependent upon its ability to bind to DNA, since PML::RARA with a missense mutation (C88A) that prevents the binding of RARA to DNA eliminates aberrant replating. Currently, however, there is no consensus regarding the genomic binding sites of PML::RARA in myeloid progenitor cells and APL cells. Also, the transcriptional and epigenetic consequences of PML::RARA expression in primary hematopoietic cells remain unclear. To define the genomic binding sites of PML::RARA, we generated V5 epitope tagged PML::RARA constructs in MSCV-based retroviral vectors, and transduced mouse hematopoietic stem progenitor cells (HSPCs) with retroviruses containing V5-PML::RARA WT, V5-PML::RARA C88A, or an empty vector. Anti-V5 ChIP-seq revealed that PML::RARA binds to 2,677 distinct loci in primary mouse hematopoietic cells, and 2,064 sites in primary human hematopoietic cells. We previously demonstrated that Gata2 expression is induced with PML::RARA, and indeed, we identified strong PML::RARA binding to the distal Gata2 enhancer in both human and mouse HSPCs. Surprisingly, ATAC-seq revealed that the vast majority of PML::RARA binding sites are found in regions that are chromatin-accessible even in WT promyelocytes, suggesting that these regions are “open” prior to PML::RARA expression, perhaps because of the normal binding of “pioneer” transcription factors to these regions in WT cells. Indeed, evaluation of transcription factor binding motifs in the regions occupied by PML::RARA revealed significant enrichment for RARA binding motifs, and also GATA motifs. We therefore performed ChIP-seq on GATA2 in HSPCs, which confirmed enrichment in binding at the same sites. These data suggested that PML::RARA and GATA2 may bind in close proximity at hundreds of loci in the genome. To test this, we performed proximity labeling studies followed by mass spectrometry using PML::RARA WT vs. PML::RARA C88A fused to the biotin ligase TurboID in primary HSPCs. This approach revealed that the interactions of several proteins with PML::RARA (including GATA2) are dependent on the binding of PML::RARA to DNA; this suggests that DNA may in fact act as a scaffold to stabilize these protein:protein interactions ( Figure 1). To determine whether Gata2 may induce increased chromatin accessibility following PML::RARA expression, we performed ATAC-seq following Gata2 or PML::RARA overexpression in WT hematopoietic progenitor cells. 3,157 regions shared increased accessibility with either PML::RARA or Gata2 overexpression. Moreover, at a transcriptional level, we found that 535 (27.4%) of PML::RARA differentially expressed genes were coordinately regulated by Gata2 in WT cells. This suggests that PML::RARA indirectly regulates many of its gene targets via the upregulation of Gata2, and that Gata2 may be required for PML::RARA to initiate its transcriptional program. To test this, we performed serial replating assays using cells where Gata2 was knocked out either before or after PML::RARA expression. Consistent with our previous study, knock out of Gata2 following PML::RARA expression led to increased self-renewal capacity. However, knock out of Gata2 before PML::RARA expression prevented self-renewal. These data suggest a model in which GATA2 “opens” specific chromatin regions in early myeloid cells, which are then accessible to RARA or PML::RARA. The two proteins interact at these sites, tethered by their mutual interactions to their respective DNA binding motifs. PML::RARA binding promotes a pre-leukemic transcriptional program mediated in part by positively regulating Gata2. Gata2 is therefore initially required for PML::RARA to establish its transcriptional program. However, once that program is established, Gata2 paradoxically acts as a tumor suppressor, performing a normal role to limit proliferative excess in hematopoietic stem and progenitor cells.

Amygdalin Improves Allergic Asthma via the Thymic Stromal Lymphopoietin–dendritic Cell–OX40 Ligand Axis in a Mouse Model

Asthma, characterized by persistent inflammation and increased sensitivity of the airway, is the most common chronic condition among children. Novel, safe, and reliable treatment strategies are the focus of current research on pediatric asthma. Amygdalin, mainly present in bitter almonds, has anti-inflammatory and immunoregulatory potential, but its effect on asthma remains uninvestigated. Here, the impact of amygdalin on the thymic stromal lymphopoietin (TSLP)–dendritic cell (DC)–OX40L axis was investigated.
 A BALB/c mouse model for allergic asthma was established using the ovalbumin-sensitization method. Amygdalin treatment was administered between days 21 and 27 of the protocol. Cell numbers and hematoxylin and eosin (H&E) staining in bronchoalveolar lavage fluid (BALF) were used to observe the impact of amygdalin on airway inflammation. TSLP, IL-4, IL-5, IL-13, and IFN-γ concentrations were determined via Enzyme-linked immunosorbent assay (ELISA). TSLP, GATA-3, and T-bet proteins were measured using western blotting. Cell-surface receptor expression on DCs (MHC II, CD80, and CD86) was assessed via flow cytometry. OX40L mRNA and protein levels were detected using western blotting and qRT-PCR, respectively.
 Amygdalin treatment attenuated airway inflammation decreased BALF TSLP levels, inhibited DC maturation, restrained TSLP-induced DC surface marker expression (MHCII, CD80, and CD86), and further decreased OX40L levels in activated DCs. This occurred together with decreased Th2 cytokine levels (IL-4, IL-5, and IL-13) and GATA3 expression, whereas Th1 cytokine (IFN-γ) levels and T-bet expression increased.
 Amygdalin thus regulates the Th1/Th2 balance through the TSLP–DC–OX40L axis to participate in inflammation development in the airways, providing a basis for potential allergic asthma treatments.

Secondary structures that regulate mRNA translation provide insights for ASO-mediated modulation of cardiac hypertrophy

Translation of upstream open reading frames (uORFs) typically abrogates translation of main (m)ORFs. The molecular mechanism of uORF regulation in cells is not well understood. Here, we data-mined human and mouse heart ribosome profiling analyses and identified a double-stranded RNA (dsRNA) structure within the GATA4 uORF that cooperates with the start codon to augment uORF translation and inhibits mORF translation. A trans-acting RNA helicase DDX3X inhibits the GATA4 uORF-dsRNA activity and modulates the translational balance of uORF and mORF. Antisense oligonucleotides (ASOs) that disrupt this dsRNA structure promote mORF translation, while ASOs that base-pair immediately downstream (i.e., forming a bimolecular double-stranded region) of either the uORF or mORF start codon enhance uORF or mORF translation, respectively. Human cardiomyocytes and mice treated with a uORF-enhancing ASO showed reduced cardiac GATA4 protein levels and increased resistance to cardiomyocyte hypertrophy. We further show the broad utility of uORF-dsRNA- or mORF-targeting ASO to regulate mORF translation for other mRNAs. This work demonstrates that the uORF-dsRNA element regulates the translation of multiple mRNAs as a generalizable translational control mechanism. Moreover, we develop a valuable strategy to alter protein expression and cellular phenotypes by targeting or generating dsRNA downstream of a uORF or mORF start codon.

Feasibility and Impact of Immunohistochemistry-based Molecular Subtyping for Muscle-invasive Bladder Cancer in Patients Treated with Radiation-based Therapy

BackgroundDistinct molecular subtypes of muscle-invasive bladder cancer (MIBC) have been identified via gene expression profiling. ObjectiveWe investigated the feasibility of a simple immunohistochemistry (IHC)-based Lund subtyping method and the association of MIBC subtypes with oncological outcomes for patients after bladder-preserving radiation-based therapy. Design, setting, and participantsTransurethral resected tumor tissues from 104 patients treated with radiation-based therapy were sampled on tissue microarray blocks. Outcome measurements and statistical analysisThe expression of KRT5, GATA3, and p16 proteins was scored via digital image analysis. Hierarchical clustering was used to classify tumors as the basal subtype or one of two luminal subtypes: genomically unstable (GU) or urothelial-like (URO). Subtypes were evaluated for association with complete response (CR), recurrence-free survival (RFS), and overall survival (OS). Results and limitationsThe median OS was 43 mo (95% confidence interval 19–77) and median follow-up was 55 mo (interquartile range 39–75). Age and clinical stage had a significant impact on OS (p < 0.05). IHC-based subtype classification was feasible in most patients (89%). The subtype was basal in 23.6%, GU in 14.0%, URO in 31.2%, and unclassified in 31.2% of patients. No significant differences in CR, RFS, or OS were observed between the molecular subtypes. Limitations include the retrospective design and relatively small sample size. ConclusionsIHC-based molecular MIBC subtyping using a three-antibody algorithm is feasible in most patients treated with radiation-based therapy. MIBC subtype was not associated with response or survival. Further prospective studies are warranted to confirm the lack of association between molecular subtype and survival in patients treated with trimodal therapy. Patient summaryFor patients with invasive bladder cancer treated with radiation-based therapy, we classified tumors into different subtypes using just three molecular stains. This method is cheaper and more widely available than the usual approach. However, we did not find an association between different cancer subtypes and survival.

Presenilin-1-Derived Circular RNAs: Neglected Epigenetic Regulators with Various Functions in Alzheimer's Disease.

The presenilin-1 (PSEN1) gene is crucial in developing Alzheimer's disease (AD), a progressive neurodegenerative disorder and the most common cause of dementia. Circular RNAs (circRNAs) are non-coding RNA generated through back-splicing, resulting in a covalently closed circular molecule. This study aimed to investigate PSEN1-gene-derived circular RNAs (circPSEN1s) and their potential functions in AD. Our in silico analysis indicated that circPSEN1s (hsa_circ_0008521 and chr14:73614502-73614802) act as sponge molecules for eight specific microRNAs. Surprisingly, two of these miRNAs (has-mir-4668-5p and has-mir-5584-5p) exclusively interact with circPSEN1s rather than mRNA-PSEN1. Furthermore, the analysis of pathways revealed that these two miRNAs predominantly target mRNAs associated with the PI3K-Akt signaling pathway. With sponging these microRNAs, circPSEN1s were found to protect mRNAs commonly targeted by these miRNAs, including QSER1, BACE2, RNF157, PTMA, and GJD3. Furthermore, the miRNAs sequestered by circPSEN1s have a notable preference for targeting the TGF-β and Hippo signaling pathways. We also demonstrated that circPSEN1s potentially interact with FOXA1, ESR1, HNF1B, BRD4, GATA4, EP300, CBX3, PRDM9, and PPARG proteins. These proteins have a prominent preference for targeting the TGF-β and Notch signaling pathways, where EP300 and FOXA1 have the highest number of protein interactions. Molecular docking analysis also confirms the interaction of these hub proteins and Aβ42 with circPSEN1s. Interestingly, circPSEN1s-targeted molecules (miRNAs and proteins) impacted TGF-β, which served as a shared signaling pathway. Finally, the analysis of microarray data unveiled distinct expression patterns of genes influenced by circPSEN1s (WTIP, TGIF, SMAD4, PPP1CB, and BMPR1A) in the brains of AD patients. In summary, our findings suggested that the interaction of circPSEN1s with microRNAs and proteins could affect the fate of specific mRNAs, interrupt the function of unique proteins, and influence cell signaling pathways, generally TGF-β. Further research is necessary to validate these findings and gain a deeper understanding of the precise mechanisms and significance of circPSEN1s in the context of AD.

Mechanisms of DHEA-induced AMH increase in the ovarian tissues of PCOS rat

The present study aimed to build a DHEA-induced polycystic ovary syndrome (PCOS) rat model to evaluate the potential mechanism of DHEA-induced AMH rise in these rat ovarian tissues. A total of 36 female 3-week-old rats were allocated into two groups at random. The control group received merely the same amount of sesame oil for 20 days while the experimental group received 0.2 mL of sesame oil Plus DHEA 6 mg/100 g daily. Both groups' vaginal opening times were noted, and vaginal smears were taken. By using RT-qPCR and Western blot, the mRNA and protein expression of AMH, GATA4, SF1, and SOX9 in the ovarian tissues of the two groups was investigated.The rats in the experimental group appeared to have obvious disorders of the estrus cycle, as evidenced by the ratio of estrus being significantly higher than that in the control group (P < 0.05); HE staining revealed that the ovarian volume, follicular vacuoles, and follicular lumen of the rats in the experimental group increased significantly.The ELISA results revealed that T and AMH in the experimental group were higher than those in the control group at day 15 and 20. AMH、GATA4 and SF1 mRNA and protein expression were higher in the experimental group than in the control group on day 15 and 20 (P < 0.05). On day 20, the experimental group outperformed the control group (P < 0.05). In the DHEA-induced PCOS rat model, androgen may have enhanced AMH expression via increasing the expression of genes associated to the AMH promoter binding site (GATA4, SF1, SOX9).

Locational memory of macrovessel vascular cells is transcriptionally imprinted

Vascular pathologies show locational predisposition throughout the body; further insights into the transcriptomics basis of this vascular heterogeneity are needed. We analyzed transcriptomes from cultured endothelial cells and vascular smooth muscle cells from nine adult canine macrovessels: the aorta, coronary artery, vena cava, portal vein, femoral artery, femoral vein, saphenous vein, pulmonary vein, and pulmonary artery. We observed that organ-specific expression patterns persist in vitro, indicating that these genes are not regulated by blood flow or surrounding cell types but are likely fixed in the epigenetic memory. We further demonstrated the preserved location-specific expression of GATA4 protein in cultured cells and in the primary adult vessel. On a functional level, arterial and venous endothelial cells differed in vascular network morphology as the arterial networks maintained a higher complexity. Our findings prompt the rethinking of the extrapolation of results from single-origin endothelial cell systems.

L-Carnitine Promotes Cardiomyogenic Differentiation of C-Kit+Bone Marrow Progenitor Cells via MAPK-ERK Signaling Pathway

Many studies have shown that bone marrow (BM) stem/progenitor cells have the highest probability of cardiomyocyte differentiation. Regarding the major role of C-kit+ BM stem cells in cell therapy of patients with heart disease and getting cells with higher differentiation potential, this study aimed to investigate the capacity and effect of L-carnitine (LC) on cardiomyogenic differentiation of C-kit+ BM cells through MAPK/ERK signaling pathway. For this purpose, C-kit+ was enriched from the BM mononuclear cell population using a magnetic activating cell sorting technique. The purity of the separated C-kit+ cells was then evaluated by flow cytometry. In the next step, C-Kit+ cells were treated in a cardiomyogenic differentiation culture medium for 21 days once in the presence and once in the absence of 0.2 µM LC (the experimental and control groups). To evaluate the cardiomyogenic differentiation potential of C-kit+ cells, the Desmin cell marker was determined by immunocytochemistry. The expressions of both GATA4 and ERK proteins were measured using western blotting and flow cytometry, respectively. The results show that 95.7 percent of the cells separated by the MACS technique expressed a C-kit+ cell marker. Additionally, it was found that 0.2 mM LC significantly increased the expression of GATA4 protein in the cardiomyogenic differentiated cells. The expression of ERK protein also suggested a significant increase of about 1.60 times in the experimental group in comparison with the control group (*P˂0.05). In brief, it was found that treating C-kit+ BM cells with LC increases cardiomyogenic differentiation by increasing the expression of GATA4. Notably, this effect can take place through MARK/ERK signaling pathway. The results of this research can be valuable in suggesting a treatment solution for cardiovascular diseases.

The role of GATA switch in benzene metabolite hydroquinone inhibiting erythroid differentiation in K562 cells.

The phenolic metabolite of benzene, hydroquinone (HQ), has potential risks for hematological disorders and hematotoxicity in humans. Previous studies have revealed that reactive oxygen species, DNA methylation, and histone acetylation participate in benzene metabolites inhibiting erythroid differentiation in hemin-induced K562 cells. GATA1 and GATA2 are crucial erythroid-specific transcription factors that exhibit dynamic expression patterns during erythroid differentiation. We investigated the role of GATA factors in HQ-inhibited erythroid differentiation in K562 cells. When K562 cells were induced with 40μM hemin for 0-120h, the mRNA and protein levels of GATA1 and GATA2 changed dynamically. After exposure to 40μM HQ for 72h, K562 cells were induced with 40μM hemin for 48h. HQ considerably reduced the percentage of hemin-induced Hb-positive cells, decreased the GATA1 mRNA, protein, and occupancy levels at α-globin and β-globin gene clusters, and increased the GATA2 mRNA and protein levels significantly. ChIP-seq analysis revealed that HQ reduced GATA1 occupancy, and increased GATA2 occupancy at most gene loci in hemin-induced K562 cells. And GATA1 and GATA2 might play essential roles in the erythroid differentiation protein interaction network. These results elucidate that HQ decreases GATA1 occupancy and increases GATA2 occupancy at the erythroid gene loci, thereby downregulating GATA1 and upregulating GATA2 expression, which in turn modulates the expression of erythroid genes and inhibits erythroid differentiation. This partially explains the mechanism of benzene hematotoxicity.

The Action and Mechanism of Trehalose on GATA4 Autophagy Degradation and Ventricular Remodeling.

To probe the effect of trehalose on myocardial hypertrophy and its specific molecular mechanism. C57BL/6J male mice were divided into four subgroups: Sham operation subgroup (Sham), negative sham subgroup (Sham+Trehalose), transverse aortic constriction (TAC), and trehalose treatment subgroup (TAC+Trehalose). Immediately after the TAC operation, trehalose at a dose of 10 mg/kg was given daily via gavage. After four weeks, changes in cardiac function were evaluated using ultrasound to measure EF (ejection fraction), FS (fractional shortening), IVRT (isovolumic relaxation time), MPI (myocardial performance index), Tau (isovolumic relaxation time constant), LVESP (left ventricular end-systolic pressure), and EDPVR (end-diastolic pressure-volume relationship). The profiles of autophagy-associated proteins (p62, LC3II/I, and Beclin-1) and GATA4 protein in mice myocardial tissues were assessed by Western blotting (WB). Myocardial cells were classified from TAC mice into five groups: Control, Trehalose, Phenylephrine (PE), PE+Trehalose, and PE+Trehalose+autophagy inhibitor chloroquine groups. In the PE group, cardiomyocytes were treated with 50 μmol/L PE. Then, the cells were treated with trehalose (100 μmol/L), trehalose (100 μmol/L)+autophagy (20 μmol/L) for 24 hours respectively. The Control group was treated with the same amount of normal saline. Flow cytometry was utilized to detect myocardial cell apoptosis in each subgroup. The alterations in apoptosis and autophagy-correlated proteins (p62, LC3II/I, and Beclin-1) were assessed by WB. Additionally, the level of GATA4 protein upstream of autophagy was estimated. Furthermore, the expression levels of pro-apoptotic proteins Bad, BAX, Cleaved-caspase-3, and anti-apoptotic protein Bcl-2 were examined by WB. The TAC operation significantly augmented myocardial hypertrophy, heart weight-to-body weight ratio, and myocardial cell apoptosis in mice (p < 0.05). Trehalose significantly improved cardiac hypertrophy, cardiomyocyte apoptosis, and cardiac function decline in mice. Additionally, it also significantly enhanced autophagy in mouse cardiac tissues (p < 0.05). At the cellular level, trehalose significantly decreased PE-elicited apoptosis and promoted the protein expressions of Beclin-1 and LC3 II/I in cardiomyocytes while significantly dampening the profiles of p62 and GATA4 in cells. The effect of trehalose and chloroquine treatment was significantly greater than that of the trehalose group. Trehalose significantly abates myocardial hypertrophy and pressure overload-induced cardiomyocyte apoptosis in mice. The cardioprotective effect of trehalose on enhanced autophagy is attributed, at least in part, to the promotion of autophagic degradation of GATA4.