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Li M, Jin H, Zhao Y, Zhu G, Liu Y, Long H, Shen X. PHD2 safeguards modest mesendoderm development. Commun Biol 2024; 7:1100. [PMID: 39244636 PMCID: PMC11380689 DOI: 10.1038/s42003-024-06824-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 09/02/2024] [Indexed: 09/09/2024] Open
Abstract
PHD2 is essential in modulating HIF-1α levels upon oxygen fluctuations. Hypoxia, a hallmark of uterus, and HIF-1α have recently emerged as opposing regulators of mesendoderm specification, suggesting a role for PHD2 therein. We found that PHD2 expression initially covered the epiblast and gradually receded from the primitive streak, which was identical to hypoxia and exclusive to HIF-1α. The investigations performed in mESCs, embryoids, and mouse embryos together demonstrated that PHD2 negatively regulated mesendoderm specification. Single-cell RNA sequencing revealed that PHD2 governed the transition from epiblast to mesendoderm. The downstream effect of PHD2 relied on the HIF-1α regulated Wnt/β-catenin pathway, while it was regulated upstream by miR-429. In summary, our research highlights PHD2's essential role in mesendoderm specification and its interactions with hypoxia and HIF-1α.
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Affiliation(s)
- Meng Li
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Huaizhang Jin
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Yun Zhao
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Guoping Zhu
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Yu Liu
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Hongan Long
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, Shandong, China
| | - Xiaopeng Shen
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China.
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2
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Jucht AE, Scholz CC. PHD1-3 oxygen sensors in vivo-lessons learned from gene deletions. Pflugers Arch 2024; 476:1307-1337. [PMID: 38509356 PMCID: PMC11310289 DOI: 10.1007/s00424-024-02944-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/02/2024] [Accepted: 03/07/2024] [Indexed: 03/22/2024]
Abstract
Oxygen sensors enable cells to adapt to limited oxygen availability (hypoxia), affecting various cellular and tissue responses. Prolyl-4-hydroxylase domain 1-3 (PHD1-3; also called Egln1-3, HIF-P4H 1-3, HIF-PH 1-3) proteins belong to the Fe2+- and 2-oxoglutarate-dependent dioxygenase superfamily and utilise molecular oxygen (O2) alongside 2-oxoglutarate as co-substrate to hydroxylate two proline residues of α subunits of the dimeric hypoxia inducible factor (HIF) transcription factor. PHD1-3-mediated hydroxylation of HIF-α leads to its degradation and inactivation. Recently, various PHD inhibitors (PHI) have entered the clinics for treatment of renal anaemia. Pre-clinical analyses indicate that PHI treatment may also be beneficial in numerous other hypoxia-associated diseases. Nonetheless, the underlying molecular mechanisms of the observed protective effects of PHIs are only partly understood, currently hindering their translation into the clinics. Moreover, the PHI-mediated increase of Epo levels is not beneficial in all hypoxia-associated diseases and PHD-selective inhibition may be advantageous. Here, we summarise the current knowledge about the relevance and function of each of the three PHD isoforms in vivo, based on the deletion or RNA interference-mediated knockdown of each single corresponding gene in rodents. This information is crucial for our understanding of the physiological relevance and function of the PHDs as well as for elucidating their individual impact on hypoxia-associated diseases. Furthermore, this knowledge highlights which diseases may best be targeted by PHD isoform-selective inhibitors in case such pharmacologic substances become available.
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Affiliation(s)
- Agnieszka E Jucht
- Institute of Physiology, University of Zurich, Zurich, 8057, Switzerland
| | - Carsten C Scholz
- Institute of Physiology, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15a, 17475, Greifswald, Germany.
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3
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Liu B, Zeng H, Su H, Williams QA, Besanson J, Chen Y, Chen JX. Endothelial Cell-Specific Prolyl Hydroxylase-2 Deficiency Augments Angiotensin II-Induced Arterial Stiffness and Cardiac Pericyte Recruitment in Mice. J Am Heart Assoc 2024; 13:e035769. [PMID: 39056332 DOI: 10.1161/jaha.124.035769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 06/18/2024] [Indexed: 07/28/2024]
Abstract
BACKGROUND Endothelial prolyl hydroxylase-2 (PHD2) is essential for pulmonary remodeling and hypertension. In the present study, we investigated the role of endothelial PHD2 in angiotensin II-mediated arterial stiffness, pericyte recruitment, and cardiac fibrosis. METHODS AND RESULTS Chondroitin sulfate proteoglycan 4 tracing reporter chondroitin sulfate proteoglycan 4- red fluorescent protein (DsRed) transgenic mice were crossed with PHD2flox/flox (PHD2f/f) mice and endothelial-specific knockout of PHD2 (PHD2ECKO) mice. Transgenic PHD2f/f (TgPHD2f/f) mice and TgPHD2ECKO mice were infused with angiotensin II for 4 weeks. Arterial thickness, stiffness, and histological and immunofluorescence of pericytes and fibrosis were measured. Infusion of TgPHD2f/f mice with angiotensin II resulted in a time-dependent increase in pulse-wave velocity. Angiotensin II-induced pulse-wave velocity was further elevated in the TgPHD2ECKO mice. TgPHD2ECKO also reduced coronary flow reserve compared with TgPHD2f/f mice infused with angiotensin II. Mechanistically, knockout of endothelial PHD2 promoted aortic arginase activity and angiotensin II-induced aortic thickness together with increased transforming growth factor-β1 and ICAM-1/VCAM-1 expression in coronary arteries. TgPHD2f/f mice infused with angiotensin II for 4 weeks exhibited a significant increase in cardiac fibrosis and hypertrophy, which was further developed in the TgPHD2ECKO mice. Chondroitin sulfate proteoglycan 4 pericyte was traced by DsRed+ staining and angiotensin II infusion displayed a significant increase of DsRed+ pericytes in the heart, as well as a deficiency of endothelial PHD2, which further promoted angiotensin II-induced pericyte increase. DsRed+ pericytes were costained with fibroblast-specific protein 1 and α-smooth muscle actin for measuring pericyte-myofibroblast cell transition. The knockout of endothelial PHD2 increased the amount of DsRed+/fibroblast-specific protein 1+ and DsRed+/α-smooth muscle actin+ cells induced by angiotensin II infusion. CONCLUSIONS Knockout of endothelial PHD2 enhanced angiotensin II-induced cardiac fibrosis by mechanisms involving increasing arterial stiffness and pericyte-myofibroblast cell transitions.
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Affiliation(s)
- Bo Liu
- Department of Pharmacology and Toxicology University of Mississippi Medical Center, School of Medicine Jackson MS
| | - Heng Zeng
- Department of Pharmacology and Toxicology University of Mississippi Medical Center, School of Medicine Jackson MS
| | - Han Su
- Department of Pharmacology and Toxicology University of Mississippi Medical Center, School of Medicine Jackson MS
| | - Quinesha A Williams
- Department of Pharmacology and Toxicology University of Mississippi Medical Center, School of Medicine Jackson MS
| | - Jessie Besanson
- Department of Pharmacology and Toxicology University of Mississippi Medical Center, School of Medicine Jackson MS
| | - Yingjie Chen
- Department of Physiology and Biophysics University of Mississippi Medical Center, School of Medicine Jackson MS
| | - Jian-Xiong Chen
- Department of Pharmacology and Toxicology University of Mississippi Medical Center, School of Medicine Jackson MS
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Liu B, Yi D, Ma X, Ramirez K, Zhao H, Xia X, Fallon MB, Kalinichenko VV, Qiu S, Dai Z. A Novel Animal Model for Pulmonary Hypertension: Lung Endothelial-Specific Deletion of Egln1 in Mice. JOURNAL OF RESPIRATORY BIOLOGY AND TRANSLATIONAL MEDICINE 2024; 1:10007. [PMID: 38974505 PMCID: PMC11225937 DOI: 10.35534/jrbtm.2024.10007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
Pulmonary arterial hypertension (PAH) is a devastating disease characterized by high blood pressure in the pulmonary arteries, which can potentially lead to heart failure over time. Previously, our lab found that endothelia-specific knockout of Egln1, encoding prolyl 4-hydroxylase-2 (PHD2), induced spontaneous pulmonary hypertension (PH). Recently, we elucidated that Tmem100 is a lung-specific endothelial gene using Tmem100-CreERT2 mice. We hypothesize that lung endothelial-specific deletion of Egln1 could lead to the development of PH without affecting Egln1 gene expression in other organs. Tmem100-CreERT2 mice were crossed with Egln1 flox/flox mice to generate Egln1 f/f ;Tmem100-CreERT2 (LiCKO) mice. Western blot and immunofluorescent staining were performed to verify the knockout efficacy of Egln1 in multiple organs of LiCKO mice. PH phenotypes, including hemodynamics, right heart size and function, pulmonary vascular remodeling, were evaluated by right heart catheterization and echocardiography measurements. Tamoxifen treatment induced Egln1 deletion in the lung endothelial cells (ECs) but not in other organs of adult LiCKO mice. LiCKO mice exhibited an increase in right ventricular systolic pressure (RVSP, ~35 mmHg) and right heart hypertrophy. Echocardiography measurements showed right heart hypertrophy, as well as cardiac and pulmonary arterial dysfunction. Pulmonary vascular remodeling, including increased pulmonary wall thickness and muscularization of distal pulmonary arterials, was enhanced in LiCKO mice compared to wild-type mice. Tmem100 promoter-mediated lung endothelial knockout of Egln1 in mice leads to development of spontaneous PH. LiCKO mice could serve as a novel mouse model for PH to study lung and other organ crosstalk.
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Affiliation(s)
- Bin Liu
- Division of Pulmonary, Critical Care and Sleep, University of Arizona, Phoenix, AZ 85004, USA
- Department of Internal Medicine, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
- Translational Cardiovascular Research Center, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Dan Yi
- Division of Pulmonary, Critical Care and Sleep, University of Arizona, Phoenix, AZ 85004, USA
- Department of Internal Medicine, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
- Translational Cardiovascular Research Center, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Xiaokuang Ma
- Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Karina Ramirez
- Division of Pulmonary, Critical Care and Sleep, University of Arizona, Phoenix, AZ 85004, USA
- Department of Internal Medicine, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Hanqiu Zhao
- Division of Pulmonary, Critical Care and Sleep, University of Arizona, Phoenix, AZ 85004, USA
- Department of Internal Medicine, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Xiaomei Xia
- Division of Pulmonary, Critical Care and Sleep, University of Arizona, Phoenix, AZ 85004, USA
- Department of Internal Medicine, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Michael B. Fallon
- Department of Internal Medicine, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Vladimir V. Kalinichenko
- Division of Neonatology, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Phoenix Children’s Health Research Institute, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Shenfeng Qiu
- Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Zhiyu Dai
- Division of Pulmonary, Critical Care and Sleep, University of Arizona, Phoenix, AZ 85004, USA
- Department of Internal Medicine, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
- Translational Cardiovascular Research Center, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
- BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA
- Sarver Heart Center, University of Arizona, Tucson, AZ 85724, USA
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5
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Ba H, Guo Y, Jiang Y, Li Y, Dai X, Liu Y, Li X. Unveiling the metabolic landscape of pulmonary hypertension: insights from metabolomics. Respir Res 2024; 25:221. [PMID: 38807129 PMCID: PMC11131231 DOI: 10.1186/s12931-024-02775-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/14/2024] [Indexed: 05/30/2024] Open
Abstract
Pulmonary hypertension (PH) is regarded as cardiovascular disease with an extremely poor prognosis, primarily due to irreversible vascular remodeling. Despite decades of research progress, the absence of definitive curative therapies remains a critical challenge, leading to high mortality rates. Recent studies have shown that serious metabolic disorders generally exist in PH animal models and patients of PH, which may be the cause or results of the disease. It is imperative for future research to identify critical biomarkers of metabolic dysfunction in PH pathophysiology and to uncover metabolic targets that could enhance diagnostic and therapeutic strategies. Metabolomics offers a powerful tool for the comprehensive qualitative and quantitative analysis of metabolites within specific organisms or cells. On the basis of the findings of the metabolomics research on PH, this review summarizes the latest research progress on metabolic pathways involved in processes such as amino acid metabolism, carbohydrate metabolism, lipid metabolism, and nucleotide metabolism in the context of PH.
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Affiliation(s)
- Huixue Ba
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China
- Department of Pharmacy, Jiangxi Provincial People's Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
| | - Yingfan Guo
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China
| | - Yujie Jiang
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China
| | - Ying Li
- Department of Health Management, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Xuejing Dai
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China
- Hunan Key Laboratory for Bioanalysis of Complex Matrix Samples, Changsha, China
| | - Yuan Liu
- Department of Anesthesiology, The Second Xiangya Hospital of Central South University, Changsha, China.
| | - Xiaohui Li
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China.
- Hunan Key Laboratory for Bioanalysis of Complex Matrix Samples, Changsha, China.
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Sultan I, Ramste M, Peletier P, Hemanthakumar KA, Ramanujam D, Tirronen A, von Wright Y, Antila S, Saharinen P, Eklund L, Mervaala E, Ylä-Herttuala S, Engelhardt S, Kivelä R, Alitalo K. Contribution of VEGF-B-Induced Endocardial Endothelial Cell Lineage in Physiological Versus Pathological Cardiac Hypertrophy. Circ Res 2024; 134:1465-1482. [PMID: 38655691 DOI: 10.1161/circresaha.123.324136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 04/08/2024] [Indexed: 04/26/2024]
Abstract
BACKGROUND Preclinical studies have shown the therapeutic potential of VEGF-B (vascular endothelial growth factor B) in revascularization of the ischemic myocardium, but the associated cardiac hypertrophy and adverse side effects remain a concern. To understand the importance of endothelial proliferation and migration for the beneficial versus adverse effects of VEGF-B in the heart, we explored the cardiac effects of autocrine versus paracrine VEGF-B expression in transgenic and gene-transduced mice. METHODS We used single-cell RNA sequencing to compare cardiac endothelial gene expression in VEGF-B transgenic mouse models. Lineage tracing was used to identify the origin of a VEGF-B-induced novel endothelial cell population and adeno-associated virus-mediated gene delivery to compare the effects of VEGF-B isoforms. Cardiac function was investigated using echocardiography, magnetic resonance imaging, and micro-computed tomography. RESULTS Unlike in physiological cardiac hypertrophy driven by a cardiomyocyte-specific VEGF-B transgene (myosin heavy chain alpha-VEGF-B), autocrine VEGF-B expression in cardiac endothelium (aP2 [adipocyte protein 2]-VEGF-B) was associated with septal defects and failure to increase perfused subendocardial capillaries postnatally. Paracrine VEGF-B led to robust proliferation and myocardial migration of a novel cardiac endothelial cell lineage (VEGF-B-induced endothelial cells) of endocardial origin, whereas autocrine VEGF-B increased proliferation of VEGF-B-induced endothelial cells but failed to promote their migration and efficient contribution to myocardial capillaries. The surviving aP2-VEGF-B offspring showed an altered ratio of secreted VEGF-B isoforms and developed massive pathological cardiac hypertrophy with a distinct cardiac vessel pattern. In the normal heart, we found a small VEGF-B-induced endothelial cell population that was only minimally expanded during myocardial infarction but not during physiological cardiac hypertrophy associated with mouse pregnancy. CONCLUSIONS Paracrine and autocrine secretions of VEGF-B induce expansion of a specific endocardium-derived endothelial cell population with distinct angiogenic markers. However, autocrine VEGF-B signaling fails to promote VEGF-B-induced endothelial cell migration and contribution to myocardial capillaries, predisposing to septal defects and inducing a mismatch between angiogenesis and myocardial growth, which results in pathological cardiac hypertrophy.
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Affiliation(s)
- Ibrahim Sultan
- Wihuri Research Institute (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., R.K., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
- Translational Cancer Medicine Program (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
| | - Markus Ramste
- Wihuri Research Institute (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., R.K., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
- Translational Cancer Medicine Program (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
| | - Pim Peletier
- Wihuri Research Institute (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., R.K., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
- Translational Cancer Medicine Program (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
| | - Karthik Amudhala Hemanthakumar
- Wihuri Research Institute (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., R.K., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
- Translational Cancer Medicine Program (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
| | - Deepak Ramanujam
- Institute of Pharmacology and Toxicology, Technical University of Munich, DZHK partner site Munich Heart Alliance, Germany (D.R., S.E.)
- RNATICS GmbH, Planegg, Germany (D.R.)
| | - Annakaisa Tirronen
- A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland (A.T., S.Y.-H.)
| | - Ylva von Wright
- Wihuri Research Institute (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., R.K., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
- Translational Cancer Medicine Program (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
| | - Salli Antila
- Wihuri Research Institute (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., R.K., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
- Translational Cancer Medicine Program (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
| | - Pipsa Saharinen
- Wihuri Research Institute (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., R.K., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
- Translational Cancer Medicine Program (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
| | - Lauri Eklund
- Oulu Center for Cell-Matrix Research, Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Finland (L.E.)
| | - Eero Mervaala
- Department of Pharmacology (E.M.), Faculty of Medicine, University of Helsinki, Finland
| | - Seppo Ylä-Herttuala
- A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland (A.T., S.Y.-H.)
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technical University of Munich, DZHK partner site Munich Heart Alliance, Germany (D.R., S.E.)
| | - Riikka Kivelä
- Wihuri Research Institute (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., R.K., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
- Stem Cells and Metabolism Research Program (R.K.), Faculty of Medicine, University of Helsinki, Finland
- Faculty of Sport and Health Sciences, University of Jyväskylä, Finland (R.K.)
| | - Kari Alitalo
- Wihuri Research Institute (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., R.K., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
- Translational Cancer Medicine Program (I.S., M.R., P.P., K.A.H., Y.v.W., S.A., P.S., K.A.), Faculty of Medicine, Biomedicum Helsinki, University of Helsinki, Finland
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Sluiter TJ, Tillie RJHA, de Jong A, de Bruijn JBG, Peters HAB, van de Leijgraaf R, Halawani R, Westmaas M, Starink LIW, Quax PHA, Sluimer JC, de Vries MR. Myeloid PHD2 Conditional Knockout Improves Intraplaque Angiogenesis and Vascular Remodeling in a Murine Model of Venous Bypass Grafting. J Am Heart Assoc 2024; 13:e033109. [PMID: 38258662 PMCID: PMC11056143 DOI: 10.1161/jaha.123.033109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 12/08/2023] [Indexed: 01/24/2024]
Abstract
BACKGROUND Intraplaque angiogenesis occurs in response to atherosclerotic plaque hypoxia, which is driven mainly by highly metabolically active macrophages. Improving plaque oxygenation by increasing macrophage hypoxic signaling, thus stimulating intraplaque angiogenesis, could restore cellular function and neovessel maturation, and decrease plaque formation. Prolyl hydroxylases (PHDs) regulate cellular responses to hypoxia. We therefore aimed to elucidate the role of myeloid PHD2, the dominant PHD isoform, on intraplaque angiogenesis in a murine model for venous bypass grafting. METHODS AND RESULTS Myeloid PHD2 conditional knockout (PHD2cko) and PHD2 wild type mice on an Ldlr-/- background underwent vein graft surgery (n=11-15/group) by interpositioning donor caval veins into the carotid artery of genotype-matched mice. At postoperative day 28, vein grafts were harvested for morphometric and compositional analysis, and blood was collected for flow cytometry. Myeloid PHD2cko induced and improved intraplaque angiogenesis by improving neovessel maturation, which reduced intraplaque hemorrhage. Intima/media ratio was decreased in myeloid PHD2cko vein grafts. In addition, PHD2 deficiency prevented dissection of vein grafts and resulted in an increase in vessel wall collagen content. Moreover, the macrophage proinflammatory phenotype in the vein graft wall was attenuated in myeloid PHD2cko mice. In vitro cultured PHD2cko bone marrow-derived macrophages exhibited an increased proangiogenic phenotype compared with control. CONCLUSIONS Myeloid PHD2cko reduces vein graft disease and ameliorates vein graft lesion stability by improving intraplaque angiogenesis.
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Affiliation(s)
- Thijs J. Sluiter
- Department of SurgeryLeiden University Medical CentreLeidenThe Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical CentreLeidenThe Netherlands
| | - Renée J. H. A. Tillie
- Department of Pathology, CARIM School for Cardiovascular SciencesMaastricht University Medical CentreMaastrichtThe Netherlands
| | - Alwin de Jong
- Department of SurgeryLeiden University Medical CentreLeidenThe Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical CentreLeidenThe Netherlands
| | - Jenny B. G. de Bruijn
- Department of Pathology, CARIM School for Cardiovascular SciencesMaastricht University Medical CentreMaastrichtThe Netherlands
| | - Hendrika A. B. Peters
- Department of SurgeryLeiden University Medical CentreLeidenThe Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical CentreLeidenThe Netherlands
| | | | - Raghed Halawani
- Department of SurgeryLeiden University Medical CentreLeidenThe Netherlands
| | - Michelle Westmaas
- Department of SurgeryLeiden University Medical CentreLeidenThe Netherlands
| | | | - Paul H. A. Quax
- Department of SurgeryLeiden University Medical CentreLeidenThe Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical CentreLeidenThe Netherlands
| | - Judith C. Sluimer
- Department of Pathology, CARIM School for Cardiovascular SciencesMaastricht University Medical CentreMaastrichtThe Netherlands
- Centre for Cardiovascular SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Margreet R. de Vries
- Department of SurgeryLeiden University Medical CentreLeidenThe Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical CentreLeidenThe Netherlands
- Department of SurgeryBrigham and Women’s Hospital, Harvard Medical SchoolBostonMA
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8
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Zhong Z, Li K, Shen C, Ma Y, Guo L. Erythropoietin improves pulmonary hypertension by promoting the homing and differentiation of bone marrow mesenchymal stem cells in lung tissue. Hum Cell 2024; 37:214-228. [PMID: 37968533 DOI: 10.1007/s13577-023-01009-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 11/05/2023] [Indexed: 11/17/2023]
Abstract
Pulmonary arterial hypertension (PAH) is a chronic disease thatultimately progresses to right-sided heart failure and death. Erythropoietin (EPO) has been shown to have therapeutic potential in cardiovascular diseases, including PAH. In this study, we aimed to investigate the improvement effect of EPO pretreated bone marrow mesenchymal stem cells (BMSCs) on PAH. BMSCs were obtained from the bone marrow of male SD rats. Female rats were randomly divided into six groups, including control group, monocrotaline (MCT)-induced group, and four groups with different doses of EPO pretreated BMSCs. Lung tissue was taken for testing at 2 weeks of treatment. Our results showed EPO promoted homing and endothelial cell differentiation of BMSCs in the lung tissues of PAH rats. EPO and BMSCs treatment attenuated pulmonary arterial pressure, polycythemia, and pulmonary artery structural remodeling. Furthermore, BMSCs inhibited pulmonary vascular endothelial-to-mesenchymal transition (EndoMT) in PAH rats, which was further suppressed by EPO in a concentration-dependent manner. Meanwhile, EPO and BMSC treatment elevated pulmonary angiogenesis in PAH rats. BMSCs inhibited TNF-α, IL-1β, IL-6, and MCP-1 in lung tissues of PAH rats, which was further decreased by EPO in a concentration-dependent manner. Thus, EPO improved pulmonary hypertension (PH) by promoting the homing and differentiation of BMSCs in lung tissue.
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Affiliation(s)
- Zhendong Zhong
- Institute for Laboratory Animal Research, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610072, Sichuan, China
| | - Kang Li
- Department of Gastroenterology, People's Hospital of Tibet Autonomous Region, Lhasa, 850000, Tibet, China
| | - Chongyang Shen
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, 230041, Sichuan, China
| | - Yuxiao Ma
- Department of Biology, New York University, 100 Washington Square E, New York, NY, 10003, United States of America.
| | - Lu Guo
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32# W. Sec 2,1St Ring Rd., Chengdu, 610072, Sichuan, China.
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Slingo ME. Oxygen-sensing pathways and the pulmonary circulation. J Physiol 2023. [PMID: 37843154 DOI: 10.1113/jp284591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/29/2023] [Indexed: 10/17/2023] Open
Abstract
The unique property of the pulmonary circulation to constrict in response to hypoxia, rather than dilate, brings advantages in both health and disease. Hypoxic pulmonary vasoconstriction (HPV) acts to optimise ventilation-perfusion matching - this is important clinically both in focal disease (such as pneumonia) and in one-lung ventilation during anaesthesia for thoracic surgery. However, during global hypoxia such as that encountered at high altitude, generalised pulmonary vasoconstriction can lead to pulmonary hypertension. There is now a growing body of evidence that links the hypoxia-inducible factor (HIF) pathway and pulmonary vascular tone - in both acute and chronic settings. Genetic and pharmacological alterations to all key components of this pathway (VHL - von Hippel-Lindau ubiquitin E3 ligase; PHD2 - prolyl hydroxylase domain protein 2; HIF1 and HIF2) have clear effects on the pulmonary circulation, particularly in hypoxia. Furthermore, knowledge of the molecular biology of the prolyl hydroxylase enzymes has led to an extensive and ongoing body of research into the importance of iron in both HPV and pulmonary hypertension. This review will explore these relationships in more detail and discuss future avenues of research.
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Affiliation(s)
- Mary E Slingo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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10
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Xi J, Ma Y, Liu D, Li R. Astragaloside IV restrains pyroptosis and fibrotic development of pulmonary artery smooth muscle cells to ameliorate pulmonary artery hypertension through the PHD2/HIF1α signaling pathway. BMC Pulm Med 2023; 23:386. [PMID: 37828459 PMCID: PMC10568875 DOI: 10.1186/s12890-023-02660-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 09/15/2023] [Indexed: 10/14/2023] Open
Abstract
BACKGROUND Astragaloside (AS)-IV, extracted from traditional Chinese medicine Astragalus mongholicus, has been widely used in the anti-inflammatory treatment for cardiovascular disease. However, the mechanism by which AS-IV affects pulmonary artery hypertension (PAH) development remains largely unknown. METHODS Monocrotaline (MCT)-induced PAH model rats were administered with AS-IV, and hematoxylin-eosin staining and Masson staining were performed to evaluate the histological change in pulmonary tissues of rats. Pulmonary artery smooth muscle cells (PASMCs) were treated by hypoxia and AS-IV. Pyroptosis and fibrosis were assessed by immunofluorescence, western blot and enzyme-linked immunosorbent assay. RESULTS AS-IV treatment alleviated pulmonary artery structural remodeling and pulmonary hypertension progression induced by MCT in rats. AS-IV suppressed the expression of pyroptosis-related markers, the release of pro-inflammatory cytokine interleukin (IL)-1β and IL-18 and fibrosis development in pulmonary tissues of PAH rats and in hypoxic PAMSCs. Interestingly, the expression of prolyl-4-hydroxylase 2 (PHD2) was restored by AS-IV administration in PAH model in vivo and in vitro, while hypoxia inducible factor 1α (HIF1α) was restrained by AS-IV. Mechanistically, silencing PHD2 reversed the inhibitory effect of AS-IV on pyroptosis, fibrosis trend and pyroptotic necrosis in hypoxia-cultured PASMCs, while the HIF1α inhibitor could prevent these PAH-like phenomena. CONCLUSION Collectively, AS-IV elevates PHD2 expression to alleviate pyroptosis and fibrosis development during PAH through downregulating HIF1α. These findings may provide a better understanding of AS-IV preventing PAH, and the PHD2/HIF1α axis may be a potential anti-pyroptosis target during PAH.
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Affiliation(s)
- Jie Xi
- Outpatient department, Urumqi Youai Hospital, Xinjiang Uygur Autonomous Region, Urumqi, 830063, China
| | - Yan Ma
- Department of Critical Care Medicine, Urumqi Youai Hospital, Urumqi, 830063, Xinjiang Uygur Autonomous Region, China.
- Department of Critical Care Medicine, Urumqi Youai Hospital, Xinjiang Uygur Autonomous Region, No. 3838, Convention and Exhibition Avenue, Midong District, Urumqi, 830063, China.
| | - Dongmei Liu
- Department of Gynaecology, Urumqi Maternal and Child Health Care Hospital, Xinjiang Uygur Autonomous Region, Urumqi, 830063, China
| | - Rong Li
- Traditional Chinese Medicine department, Urumqi Maternal and Child Health Care Hospital, Xinjiang Uygur Autonomous Region, Urumqi, 830063, China
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11
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Liu L, Huang S, Du Y, Zhou H, Zhang K, He J. Lats2 deficiency protects the heart against myocardial infarction by reducing inflammation and inhibiting mitochondrial fission and STING/p65 signaling. Int J Biol Sci 2023; 19:3428-3440. [PMID: 37497006 PMCID: PMC10367568 DOI: 10.7150/ijbs.84426] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 06/09/2023] [Indexed: 07/28/2023] Open
Abstract
Large tumor suppressor kinase 2 (Lats2) is a member of the Hippo pathway, a critical regulator of organ size. Since Lats2 activity may trigger mitochondrial dysfunction, a key pathogenic factor in acute myocardial infarction (AMI), this study sought to investigate whether Lats2 deletion confers cardioprotection in AMI. AMI was induced in cardiomyocyte-specific Lats2 knockout (Lats2Cko) and control (Lats2flox) mice. Twenty-eight days after AMI surgery, myocardial performance and mitochondrial homeostasis were impaired in Lats2floxmice. In contrast, Lats2Cko mice exhibited markedly preserved cardiac structure and contraction/relaxation activity, decreased fibrosis, reduced circulating cardiac injury biomarker levels, and enhanced cardiomyocyte viability. Consistent with these findings, siRNA-mediated Lats2 silencing sustained mitochondrial respiration and inhibited apoptosis in hypoxia-treated HL-1 cardiomyocytes. Notably, Lats2 deficiency inhibited AMI/hypoxia-related mitochondrial fission and inactivated STING/p65 signaling by preventing hypoxia-induced release of mtDNA into the cytosol. Accordingly, pharmacological reactivation of STING signaling abolished the cardioprotective effects of Lats2 ablation. Those data suggest that AMI-induced Lats2 upregulation is associated with impaired cardiomyocyte viability and function resulting from enhanced mitochondrial fission, mtDNA release, and STING/p65 pathway activation.
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Affiliation(s)
- Libao Liu
- Department of Cardiothoracic Surgery, The Third Affiliated Hospital of Sun Yat sen University, Guangzhou, Guangdong, 510620, China
| | - Shuai Huang
- Department of Cardiothoracic Surgery, The Third Affiliated Hospital of Sun Yat sen University, Guangzhou, Guangdong, 510620, China
| | - Yingzhen Du
- The Second Medical Center & National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing, 100853, China
| | - Hao Zhou
- School of Medicine, University of Rochester Medical Center Rochester, Rochester, NY 14642, United States
| | - Kai Zhang
- Department of Cardiothoracic Surgery, The Third Affiliated Hospital of Sun Yat sen University, Guangzhou, Guangdong, 510620, China
| | - Jinyuan He
- Department of Cardiothoracic Surgery, The Third Affiliated Hospital of Sun Yat sen University, Guangzhou, Guangdong, 510620, China
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12
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Sun H, Liu F, Lin Z, Jiang Z, Wen X, Xu J, Zhang Z, Ma R. Silencing of NOTCH3 Signaling in Meniscus Smooth Muscle Cells Inhibits Fibrosis and Exacerbates Degeneration in a HEYL-Dependent Manner. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2207020. [PMID: 37026620 PMCID: PMC10238196 DOI: 10.1002/advs.202207020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/08/2023] [Indexed: 06/04/2023]
Abstract
The mechanisms of meniscus fibrosis and novel ways to enhance fibrosis is unclear. This work reveals human meniscus fibrosis initiated at E24 weeks. Smooth muscle cell cluster is identified in embryonic meniscus, and the combined analysis with previous data suggests smooth muscle cell in embryonic meniscus as precursors of progenitor cells in the mature meniscus. NOTCH3 is constantly expressed in smooth muscle cells throughout embryogenesis to adulthood. Inhibition of NOTCH3 signaling in vivo inhibits meniscus fibrosis and exacerbates degeneration. Continuous histological sections show that HEYL, NOTCH3 downstream target gene, is expressed consistently with NOTCH3. HEYL knockdown in meniscus cells attenuated the COL1A1 upregulation by CTGF and TGF-β stimulation. Thus, this study discovers the existence of smooth muscle cells and fibers in the meniscus. Inhibition of NOTCH3 signaling in meniscus smooth muscle cells in a HEYL-dependent manner prevented meniscus fibrosis and exacerbated degeneration. Therefore, NOTCH3/HEYL signaling might be a potential therapeutic target for meniscus fibrosis.
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Affiliation(s)
- Hao Sun
- Department of Orthopaedic surgerySun Yat‐sen Memorial HospitalSun Yat‐sen UniversityGuangzhouGuangdong510120China
| | - Fangzhou Liu
- Department of Orthopaedic surgerySun Yat‐sen Memorial HospitalSun Yat‐sen UniversityGuangzhouGuangdong510120China
| | - Zhencan Lin
- Department of Orthopaedic surgerySun Yat‐sen Memorial HospitalSun Yat‐sen UniversityGuangzhouGuangdong510120China
| | - Zongrui Jiang
- Department of Joint SurgeryFirst Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouGuangdong510080China
| | - Xingzhao Wen
- Department of Joint SurgeryFirst Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouGuangdong510080China
| | - Jie Xu
- Department of Orthopaedic surgerySun Yat‐sen Memorial HospitalSun Yat‐sen UniversityGuangzhouGuangdong510120China
| | - Zhiqi Zhang
- Department of Joint SurgeryFirst Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouGuangdong510080China
| | - Ruofan Ma
- Department of Orthopaedic surgerySun Yat‐sen Memorial HospitalSun Yat‐sen UniversityGuangzhouGuangdong510120China
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13
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Locatelli F, Minutolo R, De Nicola L, Del Vecchio L. Evolving Strategies in the Treatment of Anaemia in Chronic Kidney Disease: The HIF-Prolyl Hydroxylase Inhibitors. Drugs 2022; 82:1565-1589. [PMID: 36350500 PMCID: PMC9645314 DOI: 10.1007/s40265-022-01783-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2022] [Indexed: 11/11/2022]
Abstract
Chronic kidney disease (CKD) affects approximately 10% of the worldwide population; anaemia is a frequent complication. Inadequate erythropoietin production and absolute or functional iron deficiency are the major causes. Accordingly, the current treatment is based on iron and erythropoiesis stimulating agents (ESAs). Available therapy has dramatically improved the management of anaemia and the quality of life. However, safety concerns were raised over ESA use, especially when aiming to reach near-to-normal haemoglobin levels with high doses. Moreover, many patients show hypo-responsiveness to ESA. Hypoxia-inducible factor (HIF) prolyl hydroxylase domain (PHD) inhibitors (HIF-PHIs) were developed for the oral treatment of anaemia in CKD to overcome these concerns. They simulate the body's exposure to moderate hypoxia, stimulating the production of endogenous erythropoietin. Some molecules are already approved for clinical use in some countries. Data from clinical trials showed non-inferiority in anaemia correction compared to ESA or superiority for placebo. Hypoxia-inducible factor-prolyl hydroxylase domain inhibitors may also have additional advantages in inflamed patients, improving iron utilisation and mobilisation and decreasing LDL-cholesterol. Overall, non-inferiority was also shown in major cardiovascular events, except for one molecule in the non-dialysis population. This was an unexpected finding, considering the lower erythropoietin levels reached using these drugs due to their peculiar mechanism of action. More data and longer follow-ups are necessary to better clarifying safety issues and further investigate the variety of pathways activated by HIF, which could have either positive or negative effects and could differentiate HIF-PHIs from ESAs.
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Affiliation(s)
- Francesco Locatelli
- Past Director of the Department of Nephrology and Dialysis, Alessandro Manzoni Hospital, via Fratelli Cairoli 60, 23900, Lecco, Italy.
| | - Roberto Minutolo
- Nephrology and Dialysis Unit, Department of Advanced Medical and Surgical Sciences, University L. Vanvitelli, Naples, Italy
| | - Luca De Nicola
- Nephrology and Dialysis Unit, Department of Advanced Medical and Surgical Sciences, University L. Vanvitelli, Naples, Italy
| | - Lucia Del Vecchio
- Department of Nephrology and Dialysis, Sant' Anna Hospital, ASST Lariana, Como, Italy
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14
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Yuan M, Zhao M, Sun X, Hui Z. The mapping of mRNA alterations elucidates the etiology of radiation-induced pulmonary fibrosis. Front Genet 2022; 13:999127. [DOI: 10.3389/fgene.2022.999127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 09/29/2022] [Indexed: 11/13/2022] Open
Abstract
The etiology of radiation-induced pulmonary fibrosis is not clearly understood yet, and effective interventions are still lacking. This study aimed to identify genes responsive to irradiation and compare the genome expression between the normal lung tissues and irradiated ones, using a radiation-induced pulmonary fibrosis mouse model. We also aimed to map the mRNA alterations as a predictive model and a potential mode of intervention for radiation-induced pulmonary fibrosis. Thirty C57BL/6 mice were exposed to a single dose of 16 Gy or 20 Gy thoracic irradiation, to establish a mouse model of radiation-induced pulmonary fibrosis. Lung tissues were harvested at 3 and 6 months after irradiation, for histological identification. Global gene expression in lung tissues was assessed by RNA sequencing. Differentially expressed genes were identified and subjected to functional and pathway enrichment analysis. Immune cell infiltration was evaluated using the CIBERSORT software. Three months after irradiation, 317 mRNAs were upregulated and 254 mRNAs were downregulated significantly in the low-dose irradiation (16 Gy) group. In total, 203 mRNAs were upregulated and 149 were downregulated significantly in the high-dose irradiation (20 Gy) group. Six months after radiation, 651 mRNAs were upregulated and 131 were downregulated significantly in the low-dose irradiation group. A total of 106 mRNAs were upregulated and 4 downregulated significantly in the high-dose irradiation group. Several functions and pathways, including angiogenesis, epithelial cell proliferation, extracellular matrix, complement and coagulation cascades, cellular senescence, myeloid leukocyte activation, regulation of lymphocyte activation, mononuclear cell proliferation, immunoglobulin binding, and the TNF, NOD-like receptor, and HIF-1 signaling pathways were significantly enriched in the irradiation groups, based on the differentially expressed genes. Irradiation-responsive genes were identified. The differentially expressed genes were mainly associated with cellular metabolism, epithelial cell proliferation, cell injury, and immune cell activation and regulation.
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15
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Kapiainen E, Elamaa H, Miinalainen I, Izzi V, Eklund L. Cooperation of Angiopoietin-2 and Angiopoietin-4 in Schlemm's Canal Maintenance. Invest Ophthalmol Vis Sci 2022; 63:1. [PMID: 36190459 PMCID: PMC9547357 DOI: 10.1167/iovs.63.11.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Defects in the iridocorneal angle tissues, including the trabecular meshwork (TM) and Schlemm's canal (SC), impair aqueous humor flow and increase the intraocular pressure (IOP), eventually resulting in glaucoma. Activation of endothelial tyrosine kinase receptor Tie2 by angiopoietin-1 (Angpt1) has been demonstrated to be essential for SC formation, but roles of the other two Tie2 ligands, Angpt2 and Angpt4, have been controversial or not yet characterized, respectively. Methods Angpt4 expression was investigated using genetic cell fate mapping and reporter mice. Congenital deletion of Angpt2 and Angpt4 and tamoxifen-inducible deletion of Angpt1 in mice were used to study the effects of Angpt4 deletion alone and in combination with the other angiopoietins. SC morphology was examined with immunofluorescent staining. IOP measurements, electron microscopy, and histologic evaluation were used to study glaucomatous changes. Results Angpt4 was postnatally expressed in the TM. While Angpt4 deletion alone did not affect SC and Angpt4 deletion did not aggravate Angpt1 deletion phenotype, absence of Angpt4 combined with Angpt2 deletion had detrimental effects on SC morphology in adult mice. Consequently, Angpt2−/−;Angpt4−/− mice displayed glaucomatous changes in the eye. Mice with Angpt2 deletion alone showed only moderate SC defects, but Angpt2 was necessary for proper limbal vasculature development. Mechanistically, analysis of Tie2 phosphorylation suggested that Angpt2 and Angpt4 cooperate as agonistic Tie2 ligands in maintaining SC integrity. Conclusions Our results indicated an additive effect of Angpt4 in SC maintenance and Tie2 activation and a spatiotemporally regulated interplay between the angiopoietins in the mouse iridocorneal angle.
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Affiliation(s)
- Emmi Kapiainen
- Oulu Center for Cell-Matrix Research, University of Oulu, Oulu, Finland.,Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Harri Elamaa
- Oulu Center for Cell-Matrix Research, University of Oulu, Oulu, Finland.,Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Ilkka Miinalainen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Valerio Izzi
- Oulu Center for Cell-Matrix Research, University of Oulu, Oulu, Finland.,Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.,Faculty of Medicine, University of Oulu, Oulu, Finland.,Foundation for the Finnish Cancer Institute, Helsinki, Finland
| | - Lauri Eklund
- Oulu Center for Cell-Matrix Research, University of Oulu, Oulu, Finland.,Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland
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