T helper 2 cells control monocyte to tissue-resident macrophage differentiation during nematode infection of the pleural cavity.

The recent revolution in tissue-resident macrophage biology has resulted largely from murine studies performed in C57BL/6 mice. Here, using both C57BL/6 and BALB/c mice, we analyze immune cells in the pleural cavity. Unlike C57BL/6 mice, naive tissue-resident large-cavity macrophages (LCMs) of BALB/c mice failed to fully implement the tissue-residency program. Following infection with a pleural-dwelling nematode, these pre-existing differences were accentuated with LCM expansion occurring in C57BL/6, but not in BALB/c mice. While infection drove monocyte recruitment in both strains, only in C57BL/6 mice were monocytes able to efficiently integrate into the resident pool. Monocyte-to-macrophage conversion required both T cells and interleukin-4 receptor alpha (IL-4Rα) signaling. The transition to tissue residency altered macrophage function, and GATA6+ tissue-resident macrophages were required for host resistance to nematode infection. Therefore, during tissue nematode infection, T helper 2 (Th2) cells control the differentiation pathway of resident macrophages, which determines infection outcome.

Gata6+ large peritoneal macrophages: an evolutionarily conserved sentinel and effector system for infection and injury.

There are striking similarities between the sea urchin cavity macrophage-like phagocytes (coelomocytes) and mammalian cavity macrophages in not only their location, but also their behaviors. These cells are crucial for maintaining homeostasis within the cavity following a breach, filling the gap and functioning as a barrier between vital organs and the environment. In this review, we summarize the evolving literature regarding these Gata6+ large peritoneal macrophages (GLPMs), focusing on ontogeny, their responses to perturbations, including their rapid aggregation via coagulation, as well as scavenger receptor cysteine-rich domains and their potential roles in diseases, such as cancer. We challenge the 50-year old phenomenon of the 'macrophage disappearance reaction' (MDR) and propose the new term 'macrophage disturbance of homeostasis reaction' (MDHR), which may better describe this complex phenomenon.

Transcriptional network governing extraembryonic endoderm cell fate choice.

The mechanism by which transcription factor (TF) network instructs cell-type-specific transcriptional programs to drive primitive endoderm (PrE) progenitors to commit to parietal endoderm (PE) versus visceral endoderm (VE) cell fates remains poorly understood. To address the question, we analyzed the single-cell transcriptional signatures defining PrE, PE, and VE cell states during the onset of the PE-VE lineage bifurcation. By coupling with the epigenomic comparison of active enhancers unique to PE and VE cells, we identified GATA6, SOX17, and FOXA2 as central regulators for the lineage divergence. Transcriptomic analysis of cXEN cells, an in vitro model for PE cells, after the acute depletion of GATA6 or SOX17 demonstrated that these factors induce Mycn, imparting the self-renewal properties of PE cells. Concurrently, they suppress the VE gene program, including key genes like Hnf4a and Ttr, among others. We proceeded with RNA-seq analysis on cXEN cells with FOXA2 knockout, in conjunction with GATA6 or SOX17 depletion. We found FOXA2 acts as a potent suppressor of Mycn while simultaneously activating the VE gene program. The antagonistic gene regulatory activities of GATA6/SOX17 and FOXA2 in promoting alternative cell fates, and their physical co-bindings at the enhancers provide molecular insights to the plasticity of the PrE lineage. Finally, we show that the external cue, BMP signaling, promotes the VE cell fate by activation of VE TFs and repression of PE TFs including GATA6 and SOX17. These data reveal a putative core gene regulatory module that underpins PE and VE cell fate choice.

The transcription factor GATA6 accelerates vascular smooth muscle cell senescence-related arterial calcification by counteracting the role of anti-aging factor SIRT6 and impeding DNA damage repair.

Arterial calcification is a hallmark of vascular pathology in the elderly and in individuals with chronic kidney disease (CKD). Vascular smooth muscle cells (VSMCs), after attaining a senescent phenotype, are implicated in the calcifying process. However, the underlying mechanism remains to be elucidated. Here, we reveal an aberrant upregulation of transcriptional factor GATA6 in the calcified aortas of humans, mice with CKD and mice subjected to vitamin D3 injection. Knockdown of GATA6, via recombinant adeno-associated virus carrying GATA6 shRNA, inhibited the development of arterial calcification in mice with CKD. Further gain- and loss-of function experiments in vitro verified the contribution of GATA6 in osteogenic differentiation of VSMCs. Samples of human aorta exhibited a positive relationship between age and GATA6 expression and GATA6 was also elevated in the aortas of old as compared to young mice. Calcified aortas displayed senescent features with VSMCs undergoing premature senescence, blunted by GATA6 downregulation. Notably, abnormal induction of GATA6 in senescent and calcified aortas was rescued in Sirtuin 6 (SIRT6)-transgenic mice, a well-established longevity mouse model. Suppression of GATA6 accounted for the favorable effect of SIRT6 on VSMCs senescence prevention. Mechanistically, SIRT6 inhibited the transcription of GATA6 by deacetylation and increased degradation of transcription factor Nkx2.5. Moreover, GATA6 was induced by DNA damage stress during arterial calcification and subsequently impeded the Ataxia-telangiectasia mutated (ATM)-mediated DNA damage repair process, leading to accelerated VSMCs senescence and osteogenic differentiation. Thus, GATA6 is a novel regulator in VSMCs senescence. Our findings provide novel insight in arterial calcification and a potential new target for intervention.

Advancing immunomodulatory functions in mesenchymal stem/stromal cells through targeting the GATA6-mediated pathway.

BACKGROUND AIMS: The immunomodulatory capacity of mesenchymal stem/stromal cells (MSCs) is a key feature that makes them particularly valuable for regenerative medicine. However, this potential is affected by the chronological aging of the donors and the cell expansion procedures in culture. We have demonstrated that GATA binding protein 6 (GATA6) plays a pivotal role in the aging of MSCs and inhibiting GATA6 rejuvenates the characteristics of MSCs. METHODS: In this study, we compared the immunomodulatory capabilities of young and old MSC models, using induced pluripotent stem cells-derived rejuvenated MSCs (rMSCs) and their parental MSCs (pMSCs), respectively, to identify a key mechanism involved in the differential regulation of these capabilities. Additionally, we explored the role of GATA6 in mediating the mechanism. RESULTS: Our results demonstrated that rMSCs exhibited downregulated aging-associated regulators, including p53, p21 and GATA6, and showed enhanced suppression of T cell proliferation compared to pMSCs. Through analyzing our previous RNA-seq data and employing target gene knockdown, we determined both suppressors of cytokine signaling 3 (SOCS3) and interleukin 6 were involved in GATA6-induced regulation, collectively affecting the expression of programmed death ligand 1 (PDL1) in both pMSCs and rMSCs. CONCLUSIONS: Our findings underline the significance of the GATA6/SOCS3/PDL1 pathway in regulating aging-associated changes in MSC immunomodulatory activity, providing valuable insights into the potential use of rMSCs in the treatment of immune diseases and regenerative medicine.

HYPOXIA induces lncRNA HOTAIR for recruiting RELA in papillary thyroid cancer cells to upregulate miR-181a and promote angiogenesis.

BACKGROUND: Papillary thyroid carcinoma (PTC) is one of the most common subtypes of thyroid carcinoma. Exosomal miR-181a plays an important role in the development of PTC. This study examined the regulatory mechanism of miR-181a under conditions of hypoxia and its impact on angiogenesis. METHODS: A ribonucleoprotein immunoprecipitation (RIP) experiment was conducted to verify the interaction between HOTAIR and RELA. The relationship between RELA and the miR-181a promoter was detected by ChIP-qPCR. Short hairpin (sh) RNA was designed to knock down HOTAIR in TPC cells. The underlying mechanism of miR-181a was verified by use of dual-luciferase assays and rescue experiments. The regulatory effect of GATA6 on angiogenesis was studied using CCK8, EdU, Transwell, and western blot assays. RESULTS: A RIP assay showed that HOTAIR could bind to RELA under hypoxic conditions. ChIP-qPCR and dual luciferase assays showed RELA could interact with the miR181a promoter and upregulate miR-181a. Knockdown of HOTAIR downregulated miR-181a in TPC-1 cells, and the downregulation could be rescued by RELA overexpression. MiR-181a downregulated GATA6 in HUVEC cells. Overexpression of GATA6 inhibited HUVEC proliferation, migration, tube formation, and EGFR expression. Exosomal miR-181a promoted angiogenesis by downregulating GATA6 expression. CONCLUSION: HOTAIR activated RELA to upregulate miR-181a during hypoxia. Exosomal miR-181a promotes tumor angiogenesis by downregulating GATA6.

Human Genetics of Truncus Arteriosus.

Integrated human genetics and molecular/developmental biology studies have revealed that truncus arteriosus is highly associated with 22q11.2 deletion syndrome. Other congenital malformation syndromes and variants in genes encoding TBX, GATA, and NKX transcription factors and some signaling proteins have also been reported as its etiology.

Human Genetics of Ventricular Septal Defect.

Ventricular septal defects (VSDs) are recognized as one of the commonest congenital heart diseases (CHD), accounting for up to 40% of all cardiac malformations, and occur as isolated CHDs as well as together with other cardiac and extracardiac congenital malformations in individual patients and families. The genetic etiology of VSD is complex and extraordinarily heterogeneous. Chromosomal abnormalities such as aneuploidy and structural variations as well as rare point mutations in various genes have been reported to be associated with this cardiac defect. This includes both well-defined syndromes with known genetic cause (e.g., DiGeorge syndrome and Holt-Oram syndrome) and so far undefined syndromic forms characterized by unspecific symptoms. Mutations in genes encoding cardiac transcription factors (e.g., NKX2-5 and GATA4) and signaling molecules (e.g., CFC1) have been most frequently found in VSD cases. Moreover, new high-resolution methods such as comparative genomic hybridization enabled the discovery of a high number of different copy number variations, leading to gain or loss of chromosomal regions often containing multiple genes, in patients with VSD. In this chapter, we will describe the broad genetic heterogeneity observed in VSD patients considering recent advances in this field.

Modulating the m6A Modified Transcription Factor GATA6 Impacts Epithelial Cytokines in Acute Lung Injury.

The methylation of m6A (N6-position of adenosine) has been found to be associated with inflammatory response. We hypothesize that m6A modification plays a role in the inflammation of airway epithelial cells during lung inflammation. However, the precise changes and functions of m6A modification in airway epithelial cells in acute lung injury (ALI) are not well understood. Here we report that METTL3 (methyltransferase-like 3)-mediated m6A of GATA6 (GATA-binding factor 6) mRNA inhibits ALI and the secretion of proinflammatory cytokines in airway epithelial cells. The expression of METTL3 and m6A levels decrease in lung tissues of mice with ALI. In cocultures, peripheral blood monocytes secreted TNF-α, which reduces METTL3 and m6A levels in the human bronchial epithelial cell line BEAS-2B. Knockdown of METTL3 promotes IL-6 and TNF-α release in BEAS-2B cells. Conversely, overexpression of METTL3 increases total RNA m6A level and reduces the levels of proinflammatory cytokines TNF-α, transforming growth factor-ß, and thymic stromal lymphopoietin. Increasing METTL3 in mouse lungs prevented LPS-induced ALI and reduced the synthesis of proinflammatory cytokines. Mechanistically, sequencing and functional analysis show that METTL3 catalyzes m6A in the 3' untranslated region of GATA6 read by YTH N6-Methyladenosine RNA Binding Protein 2 and triggers mRNA degradation. GATA6 knockdown rescues TNF-α-induced inflammatory cytokine secretion of epithelial cells, indicating that GATA6 is a main substrate of METTL3 in airway epithelial cells. Overall, this study provides evidence of a novel role for METTL3 in the inflammatory cytokine release of epithelial cells and provides an innovative therapeutic target for ALI.

Mutant Lef1 controls Gata6 in sebaceous gland development and cancer.

Mutations in Lef1 occur in human and mouse sebaceous gland (SG) tumors, but their contribution to carcinogenesis remains unclear. Since Gata6 controls lineage identity in SG, we investigated the link between these two transcription factors. Here, we show that Gata6 is a ß-catenin-independent transcriptional target of mutant Lef1. During epidermal development, Gata6 is expressed in a subset of Sox9-positive Lef1-negative hair follicle progenitors that give rise to the upper SG Overexpression of Gata6 by in utero lentiviral injection is sufficient to induce ectopic sebaceous gland elements. In mice overexpressing mutant Lef1, Gata6 ablation increases the total number of skin tumors yet decreases the proportion of SG tumors. The increased tumor burden correlates with impaired DNA mismatch repair and decreased expression of Mlh1 and Msh2 genes, defects frequently observed in human sebaceous neoplasia. Gata6 specifically marks human SG tumors and also defines tumors with elements of sebaceous differentiation, including a subset of basal cell carcinomas. Our findings reveal that Gata6 controls sebaceous gland development and cancer.

Caveolin-1 is involved in fatty infiltration and bone-tendon healing of rotator cuff tear.

BACKGROUND: Caveolin-1 has been predicted, based on RNA transcriptome sequencing, as a key gene in rotator cuff tear (RCT) and it is related to fatty infiltration. This study aims to elucidate the upstream and downstream mechanism of Caveolin-1 in fatty infiltration and bone-tendon healing after RCT in rat models. METHODS: Differentially expressed genes related to RCT were screened, followed by functional enrichment analysis and protein-protein interaction analysis. GATA6 was overexpressed and Caveolin-1 was knocked down in tendon stem cells (TSCs) to evaluate their effects on the adipogenic differentiation of TSCs. In addition, a RCT rat model was constructed and injected with lentivirus carrying oe-GATA6, oe-Caveolin-1 alone or in combination to assess their roles in fatty infiltration and bone-tendon healing. RESULTS AND CONCLUSION: Caveolin-1 was identified as a key gene involved in the RCT process. In vitro results demonstrated that Caveolin-1 knockdown inhibited adipogenic differentiation of TSCs by activating the cAMP/PKA pathway. GATA6 inhibited the transcription of Caveolin-1 and inhibited its expression, thus suppressing the adipogenic differentiation of TSCs. In vivo data confirmed that GATA6 overexpression activated the cAMP/PKA pathway by downregulating Caveolin-1 and consequently repressed fatty infiltration, promoted bone-tendon healing, improved biomechanical properties and reduced the rupture risk of injured tendon in rats after RCT. Overall, this study provides novel insights into the mechanistic action of Caveolin-1 in the fatty infiltration and bone-tendon healing after RCT.

Functional characterization of GATA6 genetic variants associated with mild congenital heart defects.

Damaging GATA6 variants can cause moderate congenital heart defects. With the application of next-generation sequencing approaches, various novel GATA6 variants with unknown significance have been identified from a broad spectrum of congenital heart defects. However, functional assessment for distinct GATA6 variants from different severity of congenital heart defects, especially from mild defects, is lacking, which hinders our understanding of the genotype-phenotype correlations and underlying mechanisms. Here, we assessed the functional consequences of nine rare GATA6 variants, which had been implicated as the most significant variants associated with mild congenital heart defects using the largest case and control cohort. We examined the effects of these variants on subcellular localization, transcriptional activity, and protein interactions in 293T or AC16 cells and their ability to rescue heart malformation in gata6 zebrafish mutant. We found that two of these nine variants, Q120X and S424I, significantly decreased transcriptional activity. Additionally, Q120X altered subcellular localization. Consistent with the in vitro results, the in vivo results showed that Q120X and S424I lost their potency to rescue ventricular malformation in gata6 -/- embryos. The results indicated that Q120X and S424I are pathogenic in mild congenital heart defects. Further, the inconsistence of severely impaired Q120X function and mild CHDs phenotype suggested the complexity of the genotype-phenotype correlation between the GATA6 variant and heart phenotype, which may help to inform prenatal genetic counseling and pre-implantation genotyping for congenital heart defects.

GATA6 and CK5 Stratify the Survival of Patients With Pancreatic Cancer Undergoing Neoadjuvant Chemotherapy.

Relevant protein expression of GATA6, CK5, vimentin, and mucins using immunohistochemistry was assessed for predicting the prognosis of and chemotherapy efficacy in patients with pancreatic cancers (PCs). The protein expression was examined in 159 PCs resected after neoadjuvant chemotherapy (NAC-PCs) and compared with that of 120 matched biopsy specimens taken before NAC. KRAS mutations were assessed by digital PCR. NAC-PCs were classified by GATA6 expression initially and CK5 expression subsequently into 4 types: classical-type (n = 22) with GATA6-high (≥50%)/CK5-low (<10%) PCs; hybrid-type (n = 45) with GATA6-high/CK5-high (≥10%) PCs; basal-like-type (n = 53) with GATA6-low (<50%)/CK5-high (≥30%) PCs; and null-type (n = 39) with GATA6-low/CK5-low (<30%) PCs, which resulted in clear stratification of patient prognosis. The classical-type was associated with the most favorable prognosis, whereas the null-type was associated with the worst prognosis (multivariate hazard ratio: 3.56; 95% CI, 1.63-7.77; P = .0015). The hybrid and basal-like types correlated with in-between levels of prognosis. The risk of hepatic recurrence was lower in the classical-type than in null (multivariate odds ratio [mOR]: 0.18; 95% CI, 0.04-0.96; P = .0449) and basal-like (mOR: 0.24; 95% CI, 0.05-1.16; P =.0750) types. By contrast, the risk of locoregional recurrence was higher in the classical-type than in the basal-like-type (mOR: 5.03; 95% CI, 1.20-21.1; P = .0272). The hybrid-type was subclassified into transition and coexpression patterns with different gastric mucin expression levels. High levels of vimentin (≥10%, n = 30) in pre-NAC-PC tissues was associated with poor prognosis (P = .0256). Phenotypic transitions between pre-NAC and post-NAC-PCs were common (73/120; 61%). PCs with NAC regression grades 2 and 3 showed a transition to poorer prognostic phenotypes (P = .0497). KRAS mutations were not associated with these phenotypes. In conclusion, GATA6 and CK5 immunohistochemical expression phenotypes may stratify the survival of patients with NAC-PCs and reflect post-NAC phenotypic transitions associated with poor prognosis. Prompt evaluation of immunohistochemical phenotypes may contribute to designing a precision therapeutic strategy for patients with PCs.

Diagnostic Accuracy of GATA6 Immunostaining in Sebaceous Tumors of the Skin.

The accurate diagnosis of skin adnexal neoplasms is sometimes challenging but is necessary because medical management and follow-up may differ between tumors. GATA6 transcription factor has been identified as a new marker of the upper folliculosebaceous compartment (lower infundibulum, junctional zone and isthmus, and upper sebaceous gland) in the human skin. We aimed to determine the diagnostic accuracy of GATA6 immunostaining to diagnose sebaceous tumors compared with that to diagnose other adnexal and nonadnexal cutaneous neoplasms. We conducted a retrospective, evaluator-nonblinded study comparing the reference standard (diagnosis by an expert dermatopathologist) with GATA6 immunostaining to identify sebaceous tumors in a cohort containing 234 different tumors. The GATA6 expression score was significatively higher in sebaceous than that in nonsebaceous tumors. In addition, tumors originating from the upper hair follicle showed positive results for GATA6 staining; however, they showed lower GATA6 expression scores. Detection of sebaceous tumors using GATA6 positivity had a sensitivity of 95.7% (95% CI, 85.8-99.2), specificity of 80.8% (95% CI, 74.5-85.8), positive predictive value of 55.6% (95% CI, 44.7-65.9), and negative predictive value of 98.7% (95% CI, 95.4-99.8). GATA6 showed similar sensitivity to adipophilin, the reference marker; however, the specificity of GATA6 was higher, as observed in a cohort of 106 tumors enriched in squamous cell carcinomas with clear-cell histology. In addition, GATA6 positivity was assessed in 39 sebaceous carcinomas and compared with epithelial membrane antigen (EMA), CK7, and androgen receptor (AR) staining results. Although CK7 staining displayed lower diagnostic performances, GATA6 staining showed comparable results as EMA and AR. Finally, we found GATA6 expression in skin metastases of gastrointestinal origin, whereas GATA6 was absent in metastases originating from breast or lung cancers. Overall, our work identified GATA6 immunostaining as a new diagnostic tool for sebaceous tumors.

GATA6-AS1 suppresses epithelial-mesenchymal transition of pancreatic cancer under hypoxia through regulating SNAI1 mRNA stability.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a hypoxic microenvironment, a high rate of heterogeneity as well as a high likelihood of recurrence. Mounting evidence has affirmed that long non-coding RNAs (lncRNAs) participate in the carcinogenesis of PDAC cells. In this study, we revealed significantly decreased expression of GATA6-AS1 in PDAC based on the GEO dataset and our cohorts, and showed that low GATA6-AS1 expression was linked to unfavorable clinicopathologic characteristics as well as a poor prognosis. Gain- and loss-of-function studies demonstrated that GATA6-AS1 suppressed the proliferation, invasion, migration, and epithelial-mesenchymal transition (EMT) process of PDAC cells under hypoxia. In vivo data confirm the suppressive roles of GATA6-AS1/SNAI1 in tumor growth and lung metastasis of PDAC. Mechanistically, hypoxia-driven E26 transformation-specific sequence-1 (ETS1), as an upstream modulatory mechanism, was essential for the downregulation of GATA6-AS1 in PDAC cells. GATA6-AS1 inhibited the expression of fat mass and obesity-associated protein (FTO), an N6-methyladenosine (m6A) eraser, and repressed SNAI1 mRNA stability in an m6A-dependent manner. Our data suggested that GATA6-AS1 can inhibit PDAC cell proliferation, invasion, migration, EMT process and metastasis under hypoxia, and disrupting the GATA6-AS1/FTO/SNAI1 axis might be a viable therapeutic approach for refractory hypoxic pancreatic cancers.

Deciphering a shared transcriptomic regulation and the relative contribution of each regulator type through endometrial gene expression signatures.

BACKGORUND: While various endometrial biomarkers have been characterized at the transcriptomic and functional level, there is generally a poor overlap among studies, making it unclear to what extent their upstream regulators (e.g., ovarian hormones, transcription factors (TFs) and microRNAs (miRNAs)) realistically contribute to menstrual cycle progression and function. Unmasking the intricacies of the molecular interactions in the endometrium from a novel systemic point of view will help gain a more accurate perspective of endometrial regulation and a better explanation the molecular etiology of endometrial-factor infertility. METHODS: An in-silico analysis was carried out to identify which regulators consistently target the gene biomarkers proposed in studies related to endometrial progression and implantation failure (19 gene lists/signatures were included). The roles of these regulators, and of genes related to progesterone and estrogens, were then analysed in transcriptomic datasets compiled from samples collected throughout the menstrual cycle (n = 129), and the expression of selected TFs were prospectively validated in an independent cohort of healthy participants (n = 19). RESULTS: A total of 3,608 distinct genes from the 19 gene lists were associated with endometrial progression and implantation failure. The lists' regulation was significantly favoured by TFs (89% (17/19) of gene lists) and progesterone (47% (8 /19) of gene lists), rather than miRNAs (5% (1/19) of gene lists) or estrogen (0% (0/19) of gene lists), respectively (FDR < 0.05). Exceptionally, two gene lists that were previously associated with implantation failure and unexplained infertility were less hormone-dependent, but primarily regulated by estrogen. Although endometrial progression genes were mainly targeted by hormones rather than non-hormonal contributors (odds ratio = 91.94, FDR < 0.05), we identified 311 TFs and 595 miRNAs not previously associated with ovarian hormones. We highlight CTCF, GATA6, hsa-miR-15a-5p, hsa-miR-218-5p, hsa-miR-107, hsa-miR-103a-3p, and hsa-miR-128-3p, as overlapping novel master regulators of endometrial function. The gene expression changes of selected regulators throughout the menstrual cycle (FDR < 0.05), dually validated in-silico and through endometrial biopsies, corroborated their potential regulatory roles in the endometrium. CONCLUSIONS: This study revealed novel hormonal and non-hormonal regulators and their relative contributions to endometrial progression and pathology, providing new leads for the potential causes of endometrial-factor infertility.

GATA6 Inhibits Neuronal Autophagy and Ferroptosis in Cerebral ischemia-reperfusion Injury Through a miR-193b/ATG7 axis-dependent Mechanism.

Ferroptosis is a newly described form of regulated necrotic cell death, which is engaged in the pathological cell death related to stroke, contributing to cerebral ischemia-reperfusion (I/R) injury. Therefore, we performed this study to clarify the role of GATA6 in neuronal autophagy and ferroptosis in cerebral I/R injury. The cerebral I/R injury-related differentially expressed genes (DEGs) as well as the downstream factors of GATA6 were predicted bioinformatically. Moreover, the relations between GATA6 and miR-193b and that between miR-193b and ATG7 were evaluated by chromatin immunoprecipitation and dual-luciferase reporter assays. Besides, neurons were treated with oxygen-glucose deprivation (OGD), followed by overexpression of GATA6, miR-193b, and ATG7 alone or in combination to assess neuronal autophagy and ferroptosis. At last, in vivo experiments were performed to explore the impacts of GATA6/miR-193b/ATG7 on neuronal autophagy and ferroptosis in a rat model of middle cerebral artery occlusion (MCAO)-stimulated cerebral I/R injury. It was found that GATA6 and miR-193b were poorly expressed in cerebral I/R injury. GATA6 transcriptionally activated miR-193b to downregulate ATG7. Additionally, GATA6-mediated miR-193b activation suppressed neuronal autophagy and ferroptosis in OGD-treated neurons by inhibiting ATG7. Furthermore, GATA6/miR-193b relieved cerebral I/R injury by restraining neuronal autophagy and ferroptosis via downregulation of ATG7 in vivo. In summary, GATA6 might prevent neuronal autophagy and ferroptosis to alleviate cerebral I/R injury via the miR-193b/ATG7 axis.

CDK7 and MITF repress a transcription program involved in survival and drug tolerance in melanoma.

Melanoma cell phenotype switching between differentiated melanocytic and undifferentiated mesenchymal-like states drives metastasis and drug resistance. CDK7 is the serine/threonine kinase of the basal transcription factor TFIIH. We show that dedifferentiation of melanocytic-type melanoma cells into mesenchymal-like cells and acquisition of tolerance to targeted therapies is achieved through chronic inhibition of CDK7. In addition to emergence of a mesenchymal-type signature, we identify a GATA6-dependent gene expression program comprising genes such as AMIGO2 or ABCG2 involved in melanoma survival or targeted drug tolerance, respectively. Mechanistically, we show that CDK7 drives expression of the melanocyte lineage transcription factor MITF that in turn binds to an intronic region of GATA6 to repress its expression in melanocytic-type cells. We show that GATA6 expression is activated in MITF-low melanoma cells of patient-derived xenografts. Taken together, our data show how the poorly characterized repressive function of MITF in melanoma participates in a molecular cascade regulating activation of a transcriptional program involved in survival and drug resistance in melanoma.

Integrin ß4 induced epithelial-to-mesenchymal transition involves miR-383 mediated regulation of GATA6 levels.

BACKGROUND: The process of transdifferentiating epithelial cells to mesenchymal-like cells (EMT) involves cells gradually taking on an invasive and migratory phenotype. Many cell adhesion molecules are crucial for the management of EMT, integrin ß4 (ITGB4) being one among them. Although signaling downstream of ITGB4 has been reported to cause changes in the expression of several miRNAs, little is known about the role of such miRNAs in the process of EMT. METHODS AND RESULTS: The cytoplasmic domain of ITGB4 (ITGB4CD) was ectopically expressed in HeLa cells to induce ITGB4 signaling, and expression analysis of mesenchymal markers indicated the induction of EMT. ß-catenin and AKT signaling pathways were found to be activated downstream of ITGB4 signaling, as evidenced by the TOPFlash assay and the levels of phosphorylated AKT, respectively. Based on in silico and qRT-PCR analysis, miR-383 was selected for functional validation studies. miR-383 and Sponge were ectopically expressed in HeLa, thereafter, western blot and qRT-PCR analysis revealed that miR-383 regulates GATA binding protein 6 (GATA6) post-transcriptionally. The ectopic expression of shRNA targeting GATA6 caused the reversal of EMT and ß catenin activation downstream of ITGB4 signaling. Cell migration assays revealed significantly high cell migration upon ectopic expression ITGB4CD, which was reversed upon ectopic co-expression of miR-383 or GATA6 shRNA. Besides, ITGB4CD promoted EMT in in ovo xenograft model, which was reversed by ectopic expression of miR-383 or GATA6 shRNA. CONCLUSION: The induction of EMT downstream of ITGB4 involves a signaling axis encompassing AKT/miR-383/GATA6/ß-catenin.

LINC00173 blocks GATA6-mediated transcription of COL5A1 to affect malignant development of oral squamous cell carcinoma.

BACKGROUND: Aberrant expression of collagen type V alpha 1 chain (COL5A1) has been linked to several forms of human cancers. In this work, we focused on the interaction of the LINC00173/GATA binding protein 6 (GATA6)/COL5A1 axis in the malignant property of oral squamous cell carcinoma (OSCC) cells. METHODS: We analyzed six publicly accessible datasets GSE160042, GSE74530, GSE138206, GSE23558, GSE31853 and GSE146483 to identify aberrantly expressed genes in OSCC. The expression of COL5A1 in OSCC tissues and cell lines was examined by reverse transcription-quantitative polymerase chain reaction and/or immunohistochemistry. The regulatory mechanism responsible for COL5A1 transcription was predicted via bioinformatics systems, and the interactions of LINC00173, GATA6, and COL5A1 were identified by immunoprecipitation and luciferase assays. Overexpression or downregulation of COL5A1, GATA6, and LINC00173 were induced in OSCC cell lines to determine their roles in the malignant phenotype of the OSCC cells in vitro and in vivo. RESULTS: COL5A1 showed elevated expression in OSCC tissues and cells. The COLA51 knockdown suppressed proliferation, migration and invasiveness, apoptosis resistance, and pro-angiogenic ability of OSCC cells, and it suppressed the growth and dissemination of xenograft tumors in vivo. GATA6 bound to COL5A1 promoter to activate its transcription, whereas LINC00173 bound to GATA6 to block this transcriptional activation. Overexpression of GATA6 or COL5A1 promoted the malignant phenotype of the OSCC cells, which were blocked upon LINC00173 upregulation. CONCLUSION: This work demonstrates that LINC00173 blocks GATA6-mediated transcription of COL5A1 to affect malignant development of OSCC.