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Xu T, Hu X, Yang G, Liu Y, Zhang Q, Yu S, Chen G, Li Y, Sha R, Chen Y, Xie HQ, Guo TL, Xu L, Zhao B. HIF-1alpha/VEGF pathway mediates 1,3,6,8-tetrabromo-9 H-carbazole-induced angiogenesis: a potential vascular toxicity of an emerging contaminant. JOURNAL OF HAZARDOUS MATERIALS 2022; 432:128718. [PMID: 35338935 DOI: 10.1016/j.jhazmat.2022.128718] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/08/2022] [Accepted: 03/14/2022] [Indexed: 06/14/2023]
Abstract
The dioxin-like substances polyhalogenated carbazoles (PHCZs) may trigger the aryl hydrocarbon receptor (AhR) signaling pathway. Although the crosstalk between AhR and the hypoxia inducible factor-1 (HIF-1) pathways is generally believed to occur, the exact mechanisms of the HIF-1 pathway in PHCZ toxicity have not been determined. We aimed to elucidate the effect of PHCZs on the HIF-1 pathway and its involvement in the regulation of target genes of HIF-1. Herein, we employed human HepG2 cells transiently transfected with a hypoxia response element (HRE) luciferase reporter to identify PHCZs that could influence HIF-1 pathway. We found that exposure to one of the four selected PHCZs, specifically 1,3,6,8-tetrabromo-9 H-carbazole (1368-BCZ), induced a significant enhancement of the activity of HRE activity. In silico data supported 1368-BCZ-induced HIF-1α activity preferentially. Moreover, 1368-BCZ significantly upregulated the expression of HIF-1 target genes, including endothelial growth factor (VEGF) and erythropoietin. Importantly, the stimulated secretion of VEGF by 1368-BCZ promoted the angiogenesis in human umbilical vein endothelial cells. Therefore, the present experimental and computational studies provide new and direct evidence of 1368-BCZ - HIF-1 interaction, which sheds light on the HIF-mediated cardiovascular toxicity and allows a knowledge-based risk assessment of emerging pollutants.
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Affiliation(s)
- Tong Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoxu Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guanglei Yang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiyun Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qian Zhang
- Department of Cardiology, Beijing Hospital, National Center of Gerontology, Beijing 100730, China
| | - Shuyuan Yu
- Environment and Health Department, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, China
| | - Guomin Chen
- Environment and Health Department, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, China
| | - Yunping Li
- School of environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Rui Sha
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yangsheng Chen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Heidi Qunhui Xie
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tai L Guo
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-0002, USA
| | - Li Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Bin Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China; School of environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
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Lin YC, Wu CY, Hu CH, Pai TW, Chen YR, Wang WD. Integrated Hypoxia Signaling and Oxidative Stress in Developmental Neurotoxicity of Benzo[a]Pyrene in Zebrafish Embryos. Antioxidants (Basel) 2020; 9:antiox9080731. [PMID: 32796530 PMCID: PMC7464806 DOI: 10.3390/antiox9080731] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/08/2020] [Accepted: 08/09/2020] [Indexed: 12/14/2022] Open
Abstract
Benzo[a]pyrene (B[a]P) is a polycyclic aromatic hydrocarbon formed by the incomplete combustion of organic matter. Environmental B[a]P contamination poses a serious health risk to many organisms because the pollutant may negatively affect many physiological systems. As such, chronic exposure to B[a]P is known to lead to locomotor dysfunction and neurodegeneration in several organisms. In this study, we used the zebrafish model to delineate the acute toxic effects of B[a]P on the developing nervous system. We found that embryonic exposure of B[a]P downregulates shh and isl1, causing morphological hypoplasia in the telencephalon, ventral thalamus, hypothalamus, epiphysis and posterior commissure. Moreover, hypoxia-inducible factors (hif1a and hif2a) are repressed upon embryonic exposure of B[a]P, leading to reduced expression of the Hif-target genes, epo and survivin, which are associated with neural differentiation and maintenance. During normal embryogenesis, low-level oxidative stress regulates neuronal development and function. However, our experiments revealed that embryonic oxidative stress is greatly increased in B[a]P-treated embryos. The expression of catalase was decreased and sod1 expression increased in B[a]P-treated embryos. These transcriptional changes were coincident with increased embryonic levels of H2O2 and malondialdehyde, with the levels in B[a]P-treated fish similar to those in embryos treated with 120-μM H2O2. Together, our data suggest that reduced Hif signaling and increased oxidative stress are involved in B[a]P-induced acute neurotoxicity during embryogenesis.
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Affiliation(s)
- Yi-Chen Lin
- Department of Bioagricultural Sciences, National Chiayi University, Chiayi City 60004, Taiwan;
| | - Chang-Yi Wu
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan;
| | - Chin-Hwa Hu
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung 20224, Taiwan;
| | - Tun-Wen Pai
- Department of Computer Science and Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan;
- Department of Computer Science and Information Engineering, National Taipei University of Technology, Taipei 10608, Taiwan
| | - Yet-Ran Chen
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11529, Taiwan;
| | - Wen-Der Wang
- Department of Bioagricultural Sciences, National Chiayi University, Chiayi City 60004, Taiwan;
- Correspondence:
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Chang J, Yang B, Zhou Y, Yin C, Liu T, Qian H, Xing G, Wang S, Li F, Zhang Y, Chen D, Aschner M, Lu R. Acute Methylmercury Exposure and the Hypoxia-Inducible Factor-1α Signaling Pathway under Normoxic Conditions in the Rat Brain and Astrocytes in Vitro. ENVIRONMENTAL HEALTH PERSPECTIVES 2019; 127:127006. [PMID: 31850806 PMCID: PMC6957278 DOI: 10.1289/ehp5139] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 11/07/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND As a ubiquitous environmental pollutant, methylmercury (MeHg) induces toxic effects in the nervous system, one of its main targets. However, the exact mechanisms of its neurotoxicity have not been fully elucidated. Hypoxia-inducible factor- 1 α (HIF- 1 α ), a transcription factor, plays a crucial role in adaptive and cytoprotective responses in cells and is involved in cell survival, proliferation, apoptosis, inflammation, angiogenesis, glucose metabolism, erythropoiesis, and other physiological activities. OBJECTIVES The aim of this study was to explore the role of HIF- 1 α in response to acute MeHg exposure in rat brain and primary cultured astrocytes to improve understanding of the mechanisms of MeHg-induced neurotoxicity and the development of effective neuroprotective strategies. METHODS Primary rat astrocytes were treated with MeHg (0 - 10 μ M ) for 0.5 h . Cell proliferation and cytotoxicity were assessed with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl diphenyltetrazolium bromide (MTT) assay and a lactate dehydrogenase (LDH) release assay, respectively. Reactive oxygen species (ROS) levels were analyzed to assess the level of oxidative stress using 2',7'-dichlorofluorescin diacetate (DCFH-DA) fluorescence. HIF- 1 α , and its downstream proteins, glucose transporter 1 (GLUT-1), erythropoietin (EPO), and vascular endothelial growth factor A (VEGF-A) were analyzed by means of Western blotting. Real-time PCR was used to detect the expression of HIF- 1 α mRNA. Pretreatment with protein synthesis inhibitor (CHX), proteasome inhibitor (MG132), or proline hydroxylase inhibitor (DHB) were applied to explore the possible mechanisms of HIF- 1 α inhibition by MeHg. To investigate the role of HIF- 1 α in MeHg-induced neurotoxicity, cobalt chloride (CoC l 2 ), 2-methoxyestradiol (2-MeOE2), small interfering RNA (siRNA) transfection and adenovirus overexpression were used. Pretreatment with N-acetyl-L-cysteine (NAC) and vitamin E (Trolox) were used to investigate the putative role of oxidative stress in MeHg-induced alterations in HIF- 1 α levels. The expression of HIF- 1 α and related downstream proteins was detected in adult rat brain exposed to MeHg (0 - 10 mg / kg ) for 0.5 h in vivo. RESULTS MeHg caused lower cell proliferation and higher cytotoxicity in primary rat astrocytes in a time- and concentration-dependent manner. In comparison with the control cells, exposure to 10 μ M MeHg for 0.5 h significantly inhibited the expression of astrocytic HIF- 1 α , and the downstream genes GLUT-1, EPO, and VEGF-A (p < 0.05 ), in the absence of a significant decrease in HIF- 1 α mRNA levels. When protein synthesis was inhibited by CHX, MeHg promoted the degradation rate of HIF- 1 α . MG132 and DHB significantly blocked the MeHg-induced decrease in HIF- 1 α expression (p < 0.05 ). Overexpression of HIF- 1 α significantly attenuated the decline in MeHg-induced cell proliferation, whereas the inhibition of HIF- 1 α significantly increased the decline in cell proliferation (p < 0.05 ). NAC and Trolox, two established antioxidants, reversed the MeHg-induced decline in HIF- 1 α protein levels and the decrease in cell proliferation (p < 0.05 ). MeHg suppressed the expression of HIF- 1 α and related downstream target proteins in adult rat brain. DISCUSSION MeHg induced a significant reduction in HIF- 1 α protein by activating proline hydroxylase (PHD) and the ubiquitin proteasome system (UPS) in primary rat astrocytes. Additionally, ROS scavenging by antioxidants played a neuroprotective role via increasing HIF- 1 α expression in response to MeHg toxicity. Moreover, we established that up-regulation of HIF- 1 α might serve to mitigate the acute toxicity of MeHg in astrocytes, affording a novel therapeutic target for future exploration. https://doi.org/10.1289/EHP5139.
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Affiliation(s)
- Jie Chang
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Bobo Yang
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Yun Zhou
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Changsheng Yin
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Tingting Liu
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Hai Qian
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Guangwei Xing
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Suhua Wang
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Fang Li
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Yubin Zhang
- Department of Occupational Health and Toxicology, School of Public Health, Fudan University, Shanghai, China
| | - Da Chen
- School of Environment, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Rongzhu Lu
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, China
- Center for Experimental Research, Kunshan Hospital Affiliated to Jiangsu University, Kunshan, China
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Abstract
The molecular mechanisms regulating sympathetic innervation of the heart during embryogenesis and its importance for cardiac development and function remain to be fully elucidated. We generated mice in which conditional knockout (CKO) of the Hif1a gene encoding the transcription factor hypoxia-inducible factor 1α (HIF-1α) is mediated by an Islet1-Cre transgene expressed in the cardiac outflow tract, right ventricle and atrium, pharyngeal mesoderm, peripheral neurons, and hindlimbs. These Hif1aCKO mice demonstrate significantly decreased perinatal survival and impaired left ventricular function. The absence of HIF-1α impaired the survival and proliferation of preganglionic and postganglionic neurons of the sympathetic system, respectively. These defects resulted in hypoplasia of the sympathetic ganglion chain and decreased sympathetic innervation of the Hif1aCKO heart, which was associated with decreased cardiac contractility. The number of chromaffin cells in the adrenal medulla was also decreased, indicating a broad dependence on HIF-1α for development of the sympathetic nervous system.
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Nebbia CS, Oswald IP, Petersen A, Rose M, Roudot AC, Schwerdtle T, Vleminckx C, Vollmer G, Wallace H, Fürst P, Håkansson H, Halldorsson T, Lundebye AK, Pohjanvirta R, Rylander L, Smith A, van Loveren H, Waalkens-Berendsen I, Zeilmaker M, Binaglia M, Gómez Ruiz JÁ, Horváth Z, Christoph E, Ciccolallo L, Ramos Bordajandi L, Steinkellner H, Hoogenboom LR. Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food. EFSA J 2018; 16:e05333. [PMID: 32625737 PMCID: PMC7009407 DOI: 10.2903/j.efsa.2018.5333] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.
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Tao J, Barnett JV, Watanabe M, Ramírez-Bergeron D. Hypoxia Supports Epicardial Cell Differentiation in Vascular Smooth Muscle Cells through the Activation of the TGFβ Pathway. J Cardiovasc Dev Dis 2018; 5:jcdd5020019. [PMID: 29652803 PMCID: PMC6023394 DOI: 10.3390/jcdd5020019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/04/2018] [Accepted: 04/04/2018] [Indexed: 12/11/2022] Open
Abstract
Epicardium-derived cells (EPDCs) are an important pool of multipotent cardiovascular progenitor cells. Through epithelial-to-mesenchymal-transition (EMT), EPDCs invade the subepicardium and myocardium and further differentiate into several cell types required for coronary vessel formation. We previously showed that epicardial hypoxia inducible factor (HIF) signaling mediates the invasion of vascular precursor cells critical for patterning the coronary vasculature. Here, we examine the regulatory role of hypoxia (1% oxygen) on EPDC differentiation into vascular smooth muscle cells (VSMCs). Results: Hypoxia stimulates EMT and enhances expression of several VSMC markers in mouse epicardial cell cultures. This stimulation is specifically blocked by inhibiting transforming growth factor-beta (TGFβ) receptor I. Further analyses indicated that hypoxia increases the expression level of TGFβ-1 ligand and phosphorylation of TGFβ receptor II, suggesting an indispensable role of the TGFβ pathway in hypoxia-stimulated VSMC differentiation. We further demonstrate that the non-canonical RhoA/Rho kinase (ROCK) pathway acts as the main downstream effector of TGFβ to modulate hypoxia’s effect on VSMC differentiation. Conclusion: Our results reveal a novel role of epicardial HIF in mediating coronary vasculogenesis by promoting their differentiation into VSMCs through noncanonical TGFβ signaling. These data elucidate that patterning of the coronary vasculature is influenced by epicardial hypoxic signals.
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Affiliation(s)
- Jiayi Tao
- Case Cardiovascular Research Institute, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
| | - Joey V Barnett
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Michiko Watanabe
- Department of Pediatrics, Rainbow Babies and Children's Hospital, The Congenital Heart Collaborative, Cleveland, OH 44106, USA.
| | - Diana Ramírez-Bergeron
- Case Cardiovascular Research Institute, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
- University Hospitals Harrington-McLaughlin Heart & Vascular Institute, Cleveland, OH 44106, USA.
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Abstract
The hearts of lower vertebrates such as fish and salamanders display scarless regeneration following injury, although this feature is lost in adult mammals. The remarkable capacity of the neonatal mammalian heart to regenerate suggests that the underlying machinery required for the regenerative process is evolutionarily retained. Recent studies highlight the epicardial covering of the heart as an important source of the signalling factors required for the repair process. The developing epicardium is also a major source of cardiac fibroblasts, smooth muscle, endothelial cells and stem cells. Here, we examine animal models that are capable of scarless regeneration, the role of the epicardium as a source of cells, signalling mechanisms implicated in the regenerative process and how these mechanisms influence cardiomyocyte proliferation. We also discuss recent advances in cardiac stem cell research and potential therapeutic targets arising from these studies.
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Affiliation(s)
| | - Nadia Rosenthal
- National Heart and Lung Institute, Imperial College London, London, UK Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria, Australia The Jackson Laboratory, Bar Harbor, ME, USA
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Yu Y, Qin J, Chen D, Wang H, Wang J, Yu Y. Chronic cardiovascular disease-associated gene network analysis in human umbilical vein endothelial cells exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. Cardiovasc Toxicol 2016; 15:157-71. [PMID: 25216946 DOI: 10.1007/s12012-014-9279-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The association of dioxin exposure with increased morbidity or mortality of chronic cardiovascular diseases (CVDs) has been established by many epidemiological studies. However, the precise global gene expression alterations caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the cardiovascular system need to be further elucidated. In this study, we profiled the gene expression of human umbilical vein endothelial cells (HUVECs) exposed to different concentrations of TCDD by high-throughput sequencing. Expression of 1,838 genes was changed significantly after TCDD stimulation. The FunDO analysis suggested that some CVDs were highly associated with TCDD treatment, including atherosclerosis, thromboangiitis obliterans, pulmonary arterial hypertension (PAH), and hypertension. KEGG pathway analysis showed that many genes in the signaling pathways of vascular smooth muscle contraction and apoptosis were altered distinctly. In addition, we revealed evidence regarding the gene network changes of chronic CVDs including atherosclerosis, thrombosis, myocardial infarction (MI), hypertension, and PAH in TCDD-exposed HUVECs. We found that gene expression of β1-adrenoceptors (ADRB1), β2-adrenoceptors (ADRB2), endothelin-converting enzyme 1 (ECE1), and endothelin-1 gene (EDN1) that are involved in the blood pressure regulation pathway decreased apparently under TCDD treatment. Moreover, the transcripts of interleukin 1 beta (IL-1β) and tumor necrosis factor α (TNFα), which are related to atherosclerosis, were up-regulated by TCDD stimulation. In addition, the transcripts of Homo sapiens collagen, type IV, alpha 1 (COL4A1), and isoforms that trigger the MI pathway were up-regulated after TCDD exposure. Finally, we found enhanced platelet-derived growth factor (PDGF) and signal transducer and activator of transcription 5 (Stat5) expression with TCDD treatment in endothelial cells, which are involved in PAH induced by vascular injury.
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Affiliation(s)
- Yu Yu
- Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 294 Taiyuan Road, Shanghai, 200031, China,
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Epicardial HIF signaling regulates vascular precursor cell invasion into the myocardium. Dev Biol 2013; 376:136-49. [PMID: 23384563 DOI: 10.1016/j.ydbio.2013.01.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 01/17/2013] [Accepted: 01/25/2013] [Indexed: 11/20/2022]
Abstract
During cardiogenesis, a subset of epicardial cells undergoes epithelial-mesenchymal-transition (EMT) and the resulting epicardial-derived cells (EPDCs) contribute to the formation of coronary vessels. Our previous data showed hypoxia inducible factor-1α (HIF-1α) expression at specific sites within the epicardium and support a link between hypoxia inducible factors (HIFs) and the patterning of coronary vasculogenesis. To better understand the autocrine role of HIFs in the epicardium, we transduced adenovirus mediated expression of constitutively active HIF-1α (AdcaHIF1α) into the embryonic avian epicardium where the vascular precursors reside. We found that introducing caHIF1α into the epicardial mesothelium prevented EPDCs from proper migration into the myocardium. In vitro collagen gel assays and ex vivo organ culture data further confirmed that infection with AdcaHIF1α impaired the ability of EPDCs to invade. However, the proficiency of epicardial cells to undergo EMT was enhanced while the movement of EPDCs within the sub-epicardium and their differentiation into smooth muscle cells were not disrupted by caHIF1α. We also showed that the transcript level of Flt-1 (VEGFR1), which can act as a VEGF signaling inhibitor, increased several fold after introducing caHIF1α into epicardial cells. Blocking the activation of the VEGF pathway in epicardial cells recapitulated the inhibition of EPDC invasion. These results suggest that caHIF1α mediated up-regulation of Flt-1, which blocks the activation of the VEGF pathway, is responsible for the inhibition of EPDC myocardial migration. In conclusion, our studies demonstrate that HIF signaling potentially regulates the degree of epicardial EMT and the extent of EPDC migration into the myocardium, both of which are likely critical in patterning the coronary vasculature during early cardiac vasculogenesis. These signals could explain why the larger coronaries appear and remain on the epicardial surface.
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