Enhanced GATA4 expression in senescent systemic lupus erythematosus monocytes promotes high levels of IFNα production.

Enhanced interferon α (IFNα) production has been implicated in the pathogenesis of systemic lupus erythematosus (SLE). We previously reported IFNα production by monocytes upon activation of the stimulator of IFN genes (STING) pathway was enhanced in patients with SLE. We investigated the mechanism of enhanced IFNα production in SLE monocytes. Monocytes enriched from the peripheral blood of SLE patients and healthy controls (HC) were stimulated with 2'3'-cyclic GAMP (2'3'-cGAMP), a ligand of STING. IFNα positive/negative cells were FACS-sorted for RNA-sequencing analysis. Gene expression in untreated and 2'3'-cGAMP-stimulated SLE and HC monocytes was quantified by real-time PCR. The effect of GATA binding protein 4 (GATA4) on IFNα production was investigated by overexpressing GATA4 in monocytic U937 cells by vector transfection. Chromatin immunoprecipitation was performed to identify GATA4 binding target genes in U937 cells stimulated with 2'3'-cGAMP. Differentially expressed gene analysis of cGAS-STING stimulated SLE and HC monocytes revealed the enrichment of gene sets related to cellular senescence in SLE. CDKN2A, a marker gene of cellular senescence, was upregulated in SLE monocytes at steady state, and its expression was further enhanced upon STING stimulation. GATA4 expression was upregulated in IFNα-positive SLE monocytes. Overexpression of GATA4 enhanced IFNα production in U937 cells. GATA4 bound to the enhancer region of IFIT family genes and promoted the expressions of IFIT1, IFIT2, and IFIT3, which promote type I IFN induction. SLE monocytes with accelerated cellular senescence produced high levels of IFNα related to GATA4 expression upon activation of the cGAS-STING pathway.

GATA4 regulates the transcription of MMP9 to suppress the invasion and migration of breast cancer cells via HDAC1-mediated p65 deacetylation.

GATA-binding protein 4 (GATA4) is recognized for its significant roles in embryogenesis and various cancers. Through bioinformatics and clinical data, it appears that GATA4 plays a role in breast cancer development. Yet, the specific roles and mechanisms of GATA4 in breast cancer progression remain elusive. In this study, we identify GATA4 as a tumor suppressor in the invasion and migration of breast cancer. Functionally, GATA4 significantly reduces the transcription of MMP9. On a mechanistic level, GATA4 diminishes MMP9 transcription by interacting with p65 at the NF-κB binding site on the MMP9 promoter. Additionally, GATA4 promotes the recruitment of HDAC1, amplifying the bond between p65 and HDAC1. This leads to decreased acetylation of p65, thus inhibiting p65's transcriptional activity on the MMP9 promoter. Moreover, GATA4 hampers the metastasis of breast cancer in vivo mouse model. In summary, our research unveils a novel mechanism wherein GATA4 curtails breast cancer cell metastasis by downregulating MMP9 expression, suggesting a potential therapeutic avenue for breast cancer metastasis.

A Genomic Link From Heart Failure to Atrial Fibrillation Risk: FOG2 Modulates a TBX5/GATA4-Dependent Atrial Gene Regulatory Network.

BACKGROUND: The relationship between heart failure (HF) and atrial fibrillation (AF) is clear, with up to half of patients with HF progressing to AF. The pathophysiological basis of AF in the context of HF is presumed to result from atrial remodeling. Upregulation of the transcription factor FOG2 (friend of GATA2; encoded by ZFPM2) is observed in human ventricles during HF and causes HF in mice. METHODS: FOG2 expression was assessed in human atria. The effect of adult-specific FOG2 overexpression in the mouse heart was evaluated by whole animal electrophysiology, in vivo organ electrophysiology, cellular electrophysiology, calcium flux, mouse genetic interactions, gene expression, and genomic function, including a novel approach for defining functional transcription factor interactions based on overlapping effects on enhancer noncoding transcription. RESULTS: FOG2 is significantly upregulated in the human atria during HF. Adult cardiomyocyte-specific FOG2 overexpression in mice caused primary spontaneous AF before the development of HF or atrial remodeling. FOG2 overexpression generated arrhythmia substrate and trigger in cardiomyocytes, including calcium cycling defects. We found that FOG2 repressed atrial gene expression promoted by TBX5. FOG2 bound a subset of GATA4 and TBX5 co-bound genomic locations, defining a shared atrial gene regulatory network. FOG2 repressed TBX5-dependent transcription from a subset of co-bound enhancers, including a conserved enhancer at the Atp2a2 locus. Atrial rhythm abnormalities in mice caused by Tbx5 haploinsufficiency were rescued by Zfpm2 haploinsufficiency. CONCLUSIONS: Transcriptional changes in the atria observed in human HF directly antagonize the atrial rhythm gene regulatory network, providing a genomic link between HF and AF risk independent of atrial remodeling.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Astaxanthin Alleviates the Process of Cardiac Hypertrophy by Targeting the METTL3/Circ_0078450/MiR-338-3p/GATA4 Pathway.

Astaxanthin (ASX) is a natural antioxidant with preventive and therapeutic effects on various human diseases. However, the role of ASX in cardiac hypertrophy and its underlying molecular mechanisms remain unclear.Cardiomyocytes (AC16) were used with angiotensin-II (Ang-II) to mimic the cardiac hypertrophy cell model. The protein levels of hypertrophy genes, GATA4, and methyltransferase-like 3 (METTL3) were determined by western blot analysis. Cell size was assessed using immunofluorescence staining. The expression of circ_0078450, miR-338-3p, and GATA4 were analyzed by quantitative real-time PCR. Also, the interaction between miR-338-3p and circ_0078450 or GATA4 was confirmed by dual-luciferase reporter and RIP assays, and the regulation of METTL3 on circ_0078450 was verified by MeRIP and RIP assays.ASX reduced the hypertrophy gene protein expression and cell size in Ang-II-induced AC16 cells. Circ_0078450 was promoted under Ang-II treatment, and ASX reduced circ_0078450 expression in Ang-II-induced AC16 cells. Circ_0078450 could sponge miR-338-3p to positively regulate GATA4 expression, and GATA4 overexpression overturned the suppressive effect of circ_0078450 knockdown on Ang-II-induced cardiomyocyte hypertrophy. Also, the inhibitory effect of ASX on Ang-II-induced cardiomyocyte hypertrophy could be reversed by circ_0078450 or GATA4 overexpression. In addition, METTL3 mediated the m6A methylation of circ_0078450 to enhance circ_0078450 expression. Moreover, METTL3 knockdown suppressed Ang-II-induced cardiomyocyte hypertrophy by inhibiting circ_0078450 expression.Our data showed that ASX repressed cardiac hypertrophy by regulating the METTL3/circ_0078450/miR-338-3p/GATA4 axis.

Relationships between Maternal Folic Acid Supplementation and GATA4 Gene Polymorphisms in Patients with Non-Chromosomal Congenital Heart Disease: A Hospital-Based Case-Control Study in China.

This study aimed to investigate the relationships between maternal FA supplementation and nine single-nucleotide variants of the GATA4 gene in non-chromosomal CHD and further explore the gene-environment interactions associated with CHD. A total of 585 CHD patients and 600 controls were recruited in the case-control study. Maternal FA (FA-containing multivitamin) supplementation information and nine polymorphisms of the GATA4 gene were collected in this study. Adjusted ORs (aOR) and their 95% confidence intervals (CIs) were calculated using proper statistical methods to analyze the relationships between the two main exposures of interest with respect to CHD. After adjusting the suspicious confounding factors, a significantly increased risk for CHD in offspring was found with non-FA supplementation before/during the pregnancy to CHD in offspring (aOR = 1.58, 95% CI: 1.01-2.48). We suggested taking FA supplementation before/during the pregnancy to prevent CHD in offspring, especially in the preconception period (aOR = 0.53, 95% CI: 0.32-0.90). The genetic results showed that the polymorphisms of rs4841588, rs12458, and rs904018 under specific genotypes and genetic models were significantly related to CHD. The gene-environment interaction between rs10108052 and FA supplementation before/during pregnancy could increase the risk of CHD (aOR = 5.38, 95% CI: 1.67-17.09, Pinteraction = 0.004). Relationships between maternal FA supplementation and specific polymorphisms of the GATA4 gene, as well as the gene-environment interaction, were significantly associated with CHD in offspring.

[High expression of Circ-PALLD in heart failure is transcriptionally regulated by the transcription factor GATA4].

OBJECTIVE: To determine the changes in the expression of circular RNA Circ-PALLD in heart failure and explore the biogenesis of Circ-PALLD. METHODS: We analyzed second-generation sequencing results of human and murine heart failure samples to identify the candidate CircRNAs. Sanger generation sequencing was performed after PCR amplification, and the sequencing results were compared to determine the reverse splicing pattern of the corresponding CircRNAs. We further examined the expressions of CircRNAs and linear RNAs in 8 patients with heart failure admitted in our hospital, and RT-qPCR was performed to detect the expression levels of Circ-PALLD and PALLD in the failing myocardium. Bioinformatic analysis was performed to predict the transcription factors that may regulate PALLD. Small interfering RNAs (siRNAs) against GATA4 were used to determine the regulatory effect of the transcription factor GATA4 on PALLD. RESULTS: Sanger sequencing and sequence alignment verified the reverse splicing of Circ-VWA8, Circ-VMP1, Circ-PRDM5, Circ-PLCL2, Circ-PALLD, Circ-NFATC3, Circ-MLIP, Circ-FAM208A, Circ-ANKIB1, and Circ-AGTPBP1, demonstrated their loop-forming nature and determined the exon arrangement of reverse splicing. Semi-quantitative PCR results showed that the expression levels of CircPALLD, Circ-NFATC3 and Circ-AGTPBP1 were significantly increased while the expression level of linear PALLD was significantly decreased in the myocardial tissues of heart failure patients. Bioinformatic analysis suggested that the transcription of PALLD was regulated possibly by the transcription factor GATA4. RT-qPCR showed that the expression level of Circ-PALLD was significantly increased, while PALLD expression was significantly decreased in the failing myocardium, which was consistent with the results of semi-quantitative PCR. In primary mammary rat cardiomyocytes, GATA4 knockdown resulted in lowered expressions of both Circ-PALLD and PALLD. CONCLUSION: Circ-PALLD is highly expressed in heart failure and can be used as a novel molecular marker for chronic heart failure, and GATA4 may play important role in regulating its transcription. Circ-PALLD points a new direction for investigating the molecular mechanism of heart failure and may also serve as a potential therapeutic target for heart failure.

GATA4 rs61277615, rs73203482, and rs35813172 in Newborns with Transposition of the Great Arteries.

Congenital heart disease is the most common malformative pathology in newborns, with a worldwide incidence at 0.4-5%. We investigated the possible relationship between variations in nucleotide sequences and specific cardiac malformations in the GATA-binding factor 4 (GATA4) exon 1 region by using Sanger sequencing. Forty-four newborns from a third-level neonatal intensive care unit who were diagnosed with nonsyndromic, ductal-dependent congenital heart disease (i.e., transposition of the great arteries or ductal-dependent coarctation of the aorta) were enrolled. Their DNA was extracted using commercial methods and tested using the multiplex ligation-dependent probe amplification (MLPA) technique. The Sanger sequencing for GATA4 exon 1 in the newborns' DNA identified rs61277615, rs73203482, and rs35813172 variants not reported in the ClinVar archive of human variations in newborns previously diagnosed with transposition of the great arteries (n=5) and coarctation of the aorta (n=1). The identification of these novel variants in newborns with transposition of the great arteries or ductal-dependent coarctation of the aorta may be the first step in determining the variants' contribution to the occurrence of congenital heart disease. However, these results may be inconclusive, since the observed variants within GATA4 gene were not previously reported.

GATA4 inhibits odontoblastic differentiation of dental pulp stem cells through targeting IGFBP3.

OBJECTIVE: The odontogenic differentiation of human dental pulp stem cells (HDPSCs) is associated with reparative dentinogenesis. Transcription factor GATA binding protein 4 (GATA4) is proved to be essential for osteoblast differentiation and bone remodeling. This study clarified the function of GATA4 in HDPSCs odontoblast differentiation. METHODS: The change in GATA4 expression during reparative dentin formation was detected by immunohistochemistry staining. The expression of GATA4 during HDPSCs odontoblastic differentiation was detected by western blot and quantitative polymerase chain reaction. The effect of GATA4 on odontoblast differentiation was investigated following overexpression lentivirus transfection. RNA sequencing, dual luciferase assay and chromatin immunoprecipitation (CHIP) were conducted to verify downstream targets of GATA4. GATA4 overexpression lentivirus and small interference RNA targeting IGFBP3 were co-transfected to investigate the regulatory mechanism of GATA4. RESULTS: Upregulated GATA4 was observed during reparative dentin formation in vivo and the odontoblastic differentiation of HDPSCs in vitro. GATA4 overexpression suppressed the odontoblastic potential of HDPSCs, demonstrated by decreased alkaline phosphatase activity (p < 0.0001), mineralized nodules formation (p < 0.01), and odonto/osteogenic differentiation markers levels (p < 0.05). RNA sequencing revealed IGFBP3 was a potential target of GATA4. CHIP and dual luciferase assays identified GATA4 could activate IGFBP3 transcription. Additionally, IGFBP3 knockdown recovered the odontoblastic differentiation defect caused by GATA4 overexpression (p < 0.05). CONCLUSIONS: GATA4 inhibited odontoblastic differentiation of HDPSCs via activating the transcriptional activity of IGFBP3, identifying its promising role in regulating HDPSCs odontoblast differentiation and reparative dentinogenesis.

Induction of Senescence by Loss of Gata4 in Cardiac Fibroblasts.

Cardiac fibroblasts are a major source of cardiac fibrosis during heart repair processes in various heart diseases. Although it has been shown that cardiac fibroblasts become senescent in response to heart injury, it is unknown how the senescence of cardiac fibroblasts is regulated in vivo. Gata4, a cardiogenic transcription factor essential for heart development, is also expressed in cardiac fibroblasts. However, it remains elusive about the role of Gata4 in cardiac fibroblasts. To define the role of Gata4 in cardiac fibroblasts, we generated cardiac fibroblast-specific Gata4 knockout mice by cross-breeding Tcf21-MerCreMer mice with Gata4fl/fl mice. Using this mouse model, we could genetically ablate Gata4 in Tcf21 positive cardiac fibroblasts in an inducible manner upon tamoxifen administration. We found that cardiac fibroblast-specific deletion of Gata4 spontaneously induces senescence in cardiac fibroblasts in vivo and in vitro. We also found that Gata4 expression in both cardiomyocytes and non-myocytes significantly decreases in the aged heart. Interestingly, when αMHC-MerCreMer mice were bred with Gata4fl/fl mice to generate cardiomyocyte-specific Gata4 knockout mice, no senescent cells were detected in the hearts. Taken together, our results demonstrate that Gata4 deficiency in cardiac fibroblasts activates a program of cellular senescence, suggesting a novel molecular mechanism of cardiac fibroblast senescence.

Potential Prognostic Value of GATA4 Depends on the p53 Expression in Primary Glioblastoma Patients.

BACKGROUND: Primary glioblastoma is characterized by an extremely poor prognosis. The promoter methylation of GATA4 leads to the loss of its expression in many cancer types. The formation of high-grade astrocytomas can be promoted by the concurrent loss of TP53 and GATA4 in normal human astrocytes. Nevertheless, the impact of GATA4 alterations with linkage to TP53 changes in gliomagenesis is poorly understood. This study aimed to evaluate GATA4 protein expression, GATA4 promoter methylation, p53 expression, TP53 promoter methylation, and mutation status in patients with primary glioblastoma and to assess the possible prognostic impact of these alterations on overall survival. MATERIALS AND METHODS: Thirty-one patients with primary glioblastoma were included. GATA4 and p53 expressions were determined immunohistochemically, and GATA4 and TP53 promoter methylations were analyzed via methylation-specific PCR. TP53 mutations were investigated via Sanger sequencing. RESULTS: The prognostic value of GATA4 depends on p53 expression. Patients without GATA4 protein expression were more frequently negative for TP53 mutations and had better prognoses than the GATA4 positive patients. In patients positive for GATA4 protein expression, p53 expression was associated with the worst outcome. However, in patients positive for p53 expression, the loss of GATA4 protein expression seemed to be associated with improved prognosis. GATA4 promoter methylation was not associated with a lack of GATA4 protein expression. CONCLUSIONS: Our data indicate that there is a possibility that GATA4 could function as a prognostic factor in glioblastoma patients, but in connection with p53 expression. A lack of GATA4 expression is not dependent on GATA4 promoter methylation. GATA4 alone has no influence on survival time in glioblastoma patients.

Methamphetamine induces cardiomyopathy through GATA4/NF-κB/SASP axis-mediated cellular senescence.

With the world pandemic of methamphetamine (METH), METH-associated cardiomyopathy (MAC) has become a widespread epidemic and is also recognized as a cause of heart failure in young people. The mechanism of occurrence and development of MAC is not clear. In this study, firstly, the animal model was evaluated by echocardiography and myocardial pathological staining. The results revealed that the animal model exhibited cardiac injury consistent with clinical alterations of MAC, and the mice developed cardiac hypertrophy and fibrosis remodeling, which led to systolic dysfunction and left ventricular ejection fraction (%LVEF) < 40%. The expression of cellular senescence marker proteins (p16 and p21) and senescence-associated secretory phenotype (SASP) was significantly increased in mouse myocardial tissue. Secondly, mRNA sequencing analysis of cardiac tissues revealed the key molecule GATA4, and Western blot, qPCR and immunofluorescence results showed that the expression level of GATA4 was significantly increased after METH exposure. Finally, knockdown of GATA4 expression in H9C2 cells in vitro significantly attenuated METH-induced cardiomyocyte senescence. Consequently, METH causes cardiomyopathy through cellular senescence mediated by the GATA4/NF-κB/SASP axis, which is a feasible target for the treatment of MAC.

Determination of Complex Formation between Drosophila Nrf2 and GATA4 Factors at Selective Chromatin Loci Demonstrates Transcription Coactivation.

Nrf2 is the dominant cellular stress response factor that protects cells through transcriptional responses to xenobiotic and oxidative stimuli. Nrf2 malfunction is highly correlated with many human diseases, but the underlying molecular mechanisms remain to be fully uncovered. GATA4 is a conserved GATA family transcription factor that is essential for cardiac and dorsal epidermal development. Here, we describe a novel interaction between Drosophila Nrf2 and GATA4 proteins, i.e., cap'n'collar C (CncC) and Pannier (Pnr), respectively. Using the bimolecular fluorescence complementation (BiFC) assay-a unique imaging tool for probing protein complexes in living cells-we detected CncC-Pnr complexes in the nuclei of Drosophila embryonic and salivary gland cells. Visualization of CncC-Pnr BiFC signals on the polytene chromosome revealed that CncC and Pnr tend to form complexes in euchromatic regions, with a preference for loci that are not highly occupied by CncC or Pnr alone. Most genes within these loci are activated by the CncC-Pnr BiFC, but not by individually expressed CncC or Pnr fusion proteins, indicating a novel mechanism whereby CncC and Pnr interact at specific genomic loci and coactivate genes at these loci. Finally, CncC-induced early lethality can be rescued by Pnr depletion, suggesting that CncC and Pnr function in the same genetic pathway during the early development of Drosophila. Taken together, these results elucidate a novel crosstalk between the Nrf2 xenobiotic/oxidative response factor and GATA factors in the transcriptional regulation of development. This study also demonstrates that the polytene chromosome BiFC assay is a valuable tool for mapping genes that are targeted by specific transcription factor complexes.

Oncogenic SIRT7 inhibits GATA4 transcriptional activity and activates the Wnt signaling pathway in ovarian cancer.

OBJECTIVE: Sirtuin-7 (SIRT7) is a class III histone deacetylase that plays an important role in cancer development and frequently overexpressed in carcinomas. In this study, the tumor-supporting role and underlying mechanisms of SIRT7 were characterized in ovarian cancer (OC) aggressiveness. METHODS: SIRT7 expression was examined in OC tissues and cells. Interactions among SIRT7, GATA4, Wnt signaling pathway were explored by bioinformatics tools and experimental validations. The effect of SIRT7 and GATA4 on malignant phenotypes of OC cells were examined with gain- and loss-of-function experiments. A nude mouse model of OC was developed to verify the in vitro findings. RESULTS: It was noted that SIRT7 was highly expressed in OC tissues and cells. Cell lines with higher SIRT7 expression (OVCAR-3 and OVCAR-8) were used for subsequent in vitro experiments. The experimental data indicated that silencing of SIRT7 suppressed the OC cell proliferation, colony formation, migration, and invasion, and promoted cell senescence, which could be abolished by GATA4 knockdown. Mechanistically, SIRT7 promoted deacetylation of GATA4 and consequently inhibited the transcriptional activity of GATA4. In addition, GATA4 induced OC cell senescence by inhibiting Wnt signaling pathway. Further in vivo experiments substantiated that SIRT7 knockdown or overexpressed GATA4 could effectively inhibit tumor growth of nude mice. CONCLUSION: Taken together, our findings indicated that SIRT7 enhanced development of OC by suppressing GATA4 and activating Wnt signaling pathway, suggesting the potential of SIRT7/GATA4/Wnt axis as a therapeutic target for OC.

Bmi-1 Overexpression Improves Sarcopenia Induced by 1,25(OH)2 D3 Deficiency and Downregulates GATA4-Dependent Rela Transcription.

Sarcopenia increases with age, and an underlying mechanism needs to be determined to help with designing more effective treatments. This study aimed to determine whether 1,25(OH)2 D3 deficiency could cause cellular senescence and a senescence-associated secretory phenotype (SASP) in skeletal muscle cells to induce sarcopenia, whether GATA4 could be upregulated by 1,25(OH)2 D3 deficiency to promote SASP, and whether Bmi-1 reduces the expression of GATA4 and GATA4-dependent SASP induced by 1,25(OH)2 D3 deficiency in skeletal muscle cells. Bioinformatics analyses with RNA sequencing data in skeletal muscle from physiologically aged and young mice were conducted. Skeletal muscles from 2-month-old young and 2-year-old physiologically aged wild-type (WT) mice and 8-week-old WT, Bmi-1 mesenchymal transgene (Bmi-1Tg ), Cyp27b1 homozygous (Cyp27b1-/- ), and Bmi-1Tg Cyp27b1-/- mice were observed for grip strength, cell senescence, DNA damage, and NF-κB-mediated SASP signaling of skeletal muscle. We found that muscle-derived Bmi-1 and vitamin D receptor (VDR) decreased with physiological aging, and DNA damage and GATA4-dependent SASP activation led to sarcopenia. Furthermore, 1,25(OH)2 D3 deficiency promoted DNA damage-induced GATA4 accumulation in muscles. GATA4 upregulated Rela at the region from -1448 to -1412 bp at the transcriptional level to cause NF-κB-dependent SASP for aggravating cell senescence and muscular dysfunction and sarcopenia. Bmi-1 overexpression promoted the ubiquitination and degradation of GATA4 by binding RING1B, which prevented cell senescence, SASP, and dysfunctional muscle, and improved sarcopenia induced by 1,25(OH)2 D3 deficiency. Thus, Bmi-1 overexpression improves sarcopenia induced by 1,25(OH)2 D3 deficiency, downregulates GATA4-dependent Rela transcription, and sequentially inhibits GATA4-dependent SASP in muscle cells. Therefore, Bmi-1 overexpression could be used for translational gene therapy for the ubiquitination of GATA4 and prevention of sarcopenia. © 2023 American Society for Bone and Mineral Research (ASBMR).

GATA4 and GATA6 loss-of-expression is associated with extinction of the classical programme and poor outcome in pancreatic ductal adenocarcinoma.

OBJECTIVE: GATA6 is a key regulator of the classical phenotype in pancreatic ductal adenocarcinoma (PDAC). Low GATA6 expression associates with poor patient outcome. GATA4 is the second most expressed GATA factor in the pancreas. We assessed whether, and how, GATA4 contributes to PDAC phenotype and analysed the association of expression with outcome and response to chemotherapy. DESIGN: We analysed PDAC transcriptomic data, stratifying cases according to GATA4 and GATA6 expression and identified differentially expressed genes and pathways. The genome-wide distribution of GATA4 was assessed, as well as the effects of GATA4 knockdown. A multicentre tissue microarray study to assess GATA4 and GATA6 expression in samples (n=745) from patients with resectable was performed. GATA4 and GATA6 levels were dichotomised into high/low categorical variables; association with outcome was assessed using univariable and multivariable Cox regression models. RESULTS: GATA4 messenger RNA is enriched in classical, compared with basal-like tumours. We classified samples in 4 groups as high/low for GATA4 and GATA6. Reduced expression of GATA4 had a minor transcriptional impact but low expression of GATA4 enhanced the effects of GATA6 low expression. GATA4 and GATA6 display a partially overlapping genome-wide distribution, mainly at promoters. Reduced expression of both proteins in tumours was associated with the worst patient survival. GATA4 and GATA6 expression significantly decreased in metastases and negatively correlated with basal markers. CONCLUSIONS: GATA4 and GATA6 cooperate to maintain the classical phenotype. Our findings provide compelling rationale to assess their expression as biomarkers of poor prognosis and therapeutic response.

Bicuspid Aortic Valve-Associated Regulatory Regions Reveal GATA4 Regulation and Function During Human-Induced Pluripotent Stem Cell-Based Endothelial-Mesenchymal Transition-Brief Report.

BACKGROUND: The endothelial-mesenchymal transition (EndoMT) is a fundamental process for heart valve formation and defects in EndoMT cause aortic valve abnormalities. Our previous genome-wide association study identified multiple variants in a large chromosome 8 segment as significantly associated with bicuspid aortic valve (BAV). The objective of this study is to determine the biological effects of this large noncoding segment in human induced pluripotent stem cell (hiPSC)-based EndoMT. METHODS: A large genomic segment enriched for BAV-associated variants was deleted in hiPSCs using 2-step CRISPR/Cas9 editing. To address the effects of the variants on GATA4 expression, we generated CRISPR repression hiPSC lines (CRISPRi) as well as hiPSCs from BAV patients. The resulting hiPSCs were differentiated to mesenchymal/myofibroblast-like cells through cardiovascular-lineage endothelial cells for molecular and cellular analysis. Single-cell RNA sequencing was also performed at different stages of EndoMT induction. RESULTS: The large deletion impaired hiPSC-based EndoMT in multiple biallelic clones compared with their isogenic control. It also reduced GATA4 transcript and protein levels during EndoMT, sparing the other genes nearby the deletion segment. Single-cell trajectory analysis revealed the molecular reprogramming during EndoMT. Putative GATA-binding protein targets during EndoMT were uncovered, including genes implicated in endocardial cushion formation and EndoMT process. Differentiation of cells derived from BAV patients carrying the rs117430032 variant as well as CRISPRi repression of the rs117430032 locus resulted in lower GATA4 expression in a stage-specific manner. TWIST1 was identified as a potential regulator of GATA4 expression, showing specificity to the locus tagged by rs117430032. CONCLUSIONS: BAV-associated distal regions regulate GATA4 expression during hiPSC-based EndoMT, which in turn promotes EndoMT progression, implicating its contribution to heart valve development.

Deleting Gata4 in hepatocytes promoted the progression of NAFLD via increasing steatosis and apoptosis, and desensitizing insulin signaling.

Gata4 is a member of the zinc finger GATA transcription factor family and is required for liver development during the embryonic stage. Gata4 expression is repressed during NAFLD progression, however how it functions in this situation remains unclear. Here, Gata4 was deleted specifically in hepatocytes via Cre recombinase driven by the Alb promoter region. Under a high-fat diet (HFD) or methionine and choline deficient diet (MCD), Gata4 knockout (KO) male, but not female, mice displayed more severe NAFLD or NASH, evidenced by increased steatosis, fibrosis, as well as a higher NAS score and serum ALT level. The Gata4KO male liver exposed to a HFD or MCD had a reduced ratio of pACC/ACC, similar to the Gata4KO hepatocytes treated with palmitic acid. More cell apoptosis, which is associated with activated JNK signaling and inhibited NFκB signaling, was observed in the Gata4KO male liver and isolated hepatocytes. However, the inflammatory status in the Gata4KO male liver was similar to the control liver. Importantly, lower activation of AKT signaling in the liver, which is consistent with de-sensitized insulin signaling in isolated hepatocytes, was found in the Gata4KO male. In summary, our data demonstrated that loss of Gata4 in hepatocytes promoted NAFLD progression in male mice.

Hepatic GATA4 regulates cholesterol and triglyceride homeostasis in collaboration with LXRs.

GATA4 is a transcription factor known for its crucial role in the development of many tissues, including the liver; however, its role in adult liver metabolism is unknown. Here, using high-throughput sequencing technologies, we identified GATA4 as a transcriptional regulator of metabolism in the liver. GATA4 expression is elevated in response to refeeding, and its occupancy is increased at enhancers of genes linked to fatty acid and lipoprotein metabolism. Knocking out GATA4 in the adult liver (Gata4LKO) decreased transcriptional activity at GATA4 binding sites, especially during feeding. Gata4LKO mice have reduced plasma HDL cholesterol and increased liver triglyceride levels. The expression of a panel of GATA4 binding genes involved in hepatic cholesterol export and triglyceride hydrolysis was down-regulated in Gata4LKO mice. We further demonstrate that GATA4 collaborates with LXR nuclear receptors in the liver. GATA4 and LXRs share a number of binding sites, and GATA4 was required for the full transcriptional response to LXR activation. Collectively, these results show that hepatic GATA4 contributes to the transcriptional control of hepatic and systemic lipid homeostasis.

a1-adrenergic receptors accompanied by GATA4 expression are related to proarrhythmic conduction and automaticity in rat interatrial septum

The development of interatrial septum (IAS) is a complicated process, which continues during postnatal life. The hypertrophic signals in developing heart are mediated among others by α-adrenergic pathways. These facts suggest the presence of specific electrophysiological features in developing IAS. This study was aimed to investigate the electrical activity in the tissue preparations of IAS from rat heart in normal conditions and under stimulation of adrenoreceptors. Intracellular recording of electrical activity revealed less negative level of resting membrane potential in IAS if compared to myocardium of left atrium. In normal conditions, non-paced IAS preparations were quiescent, but noradrenaline (10−5 M) and phenylephrine (10−5 M) induced spontaneous action potentials, which could be abolished by α1-blocker prazosin (10−5 M), but not β1-blocker atenolol (10−5 M). Optical mapping showed drastic phenylephrine-induced slowing of conduction in adult rat IAS. The α1-dependent ectopic automaticity of IAS myocardium might be explained by immunohistochemical data indicating the presence of transcription factor GATA4 and abundant α1A-adrenoreceptors in myocytes from adult rat IAS. An elevated sensitivity to adrenergic stimulation due to involvement of α1-adrenergic pathways may underlie increased proarrhythmic potential of adult IAS at least in rats. (AU)