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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 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] [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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2
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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: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] [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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3
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Zhao X, Xue X, Cui Z, Kwame Amevor F, Wan Y, Fu K, Wang C, Peng C, Li Y. microRNAs-based diagnostic and therapeutic applications in liver fibrosis. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022:e1773. [PMID: 36585388 DOI: 10.1002/wrna.1773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/05/2022] [Accepted: 12/12/2022] [Indexed: 01/01/2023]
Abstract
Liver fibrosis is a process of over-extracellular matrix (ECM) aggregation and angiogenesis, which develops into cirrhosis and hepatocellular carcinoma (HCC). With the increasing pressure of liver fibrosis, new therapeutics to cure this disease requires much attention. Exosome-cargoed microRNAs (miRNAs) are emerging approaches in the precision of the liver fibrotic paradigm. In this review, we outlined the different types of hepatic cells derived miRNAs that drive intra-/extra-cellular interactive communication in liver fibrosis with different physiological and pathological processes. Specifically, we highlighted the possible mechanism of liver fibrosis pathogenesis associated with immune response and angiogenesis. In addition, potential clinical biomarkers and different stem cell transplant-derived miRNAs-based therapeutic strategies in liver fibrosis were summarized in this review. miRNAs-based approaches might help researchers devise new candidates for the cell-free treatment of liver fibrosis. This article is categorized under: RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Xingtao Zhao
- State Key Laboratory of Southwestern Chinese Medicine Resources, Ministry of Education, Chengdu, China.,School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xinyan Xue
- State Key Laboratory of Southwestern Chinese Medicine Resources, Ministry of Education, Chengdu, China.,School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Zhifu Cui
- College Science and Technology, Southwest University, Chongqing, China
| | - Felix Kwame Amevor
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Yan Wan
- State Key Laboratory of Southwestern Chinese Medicine Resources, Ministry of Education, Chengdu, China.,School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Ke Fu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Ministry of Education, Chengdu, China.,School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Cheng Wang
- State Key Laboratory of Southwestern Chinese Medicine Resources, Ministry of Education, Chengdu, China.,School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Cheng Peng
- State Key Laboratory of Southwestern Chinese Medicine Resources, Ministry of Education, Chengdu, China.,School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yunxia Li
- State Key Laboratory of Southwestern Chinese Medicine Resources, Ministry of Education, Chengdu, China.,School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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4
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Leung SWS, Shi Y. The glycolytic process in endothelial cells and its implications. Acta Pharmacol Sin 2022; 43:251-259. [PMID: 33850277 PMCID: PMC8791959 DOI: 10.1038/s41401-021-00647-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 02/22/2021] [Indexed: 02/06/2023] Open
Abstract
Endothelial cells play an obligatory role in regulating local vascular tone and maintaining homeostasis in vascular biology. Cell metabolism, converting food to energy in organisms, is the primary self-sustaining mechanism for cell proliferation and reproduction, structure maintenance, and fight-or-flight responses to stimuli. Four major metabolic processes take place in the energy-producing process, including glycolysis, oxidative phosphorylation, glutamine metabolism, and fatty acid oxidation. Among them, glycolysis is the primary energy-producing mechanism in endothelial cells. The present review focused on glycolysis in endothelial cells under both physiological and pathological conditions. Since the switches among metabolic processes precede the functional changes and disease developments, some prophylactic and/or therapeutic strategies concerning the role of glycolysis in cardiovascular disease are discussed.
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Affiliation(s)
- Susan, Wai Sum Leung
- grid.194645.b0000000121742757Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Yi Shi
- grid.8547.e0000 0001 0125 2443Institute of Clinical Science, Zhongshan Hospital, Fudan University, Shanghai, 200032 China ,grid.8547.e0000 0001 0125 2443Key Laboratory of Organ Transplantation, Zhongshan Hospital, Fudan University, Shanghai, 200032 China
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5
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Yang J, Tan H, Sun M, Chen R, Zhang J, Liu C, Yang Y, Ding X, Yu S, Gu W, Ke J, Shen Y, Zhang C, Gao X, Li C, Huang L. Prediction of High-Altitude Cardiorespiratory Fitness Impairment Using a Combination of Physiological Parameters During Exercise at Sea Level and Genetic Information in an Integrated Risk Model. Front Cardiovasc Med 2022; 8:719776. [PMID: 35071338 PMCID: PMC8782201 DOI: 10.3389/fcvm.2021.719776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 11/30/2021] [Indexed: 11/25/2022] Open
Abstract
Insufficient cardiorespiratory compensation is closely associated with acute hypoxic symptoms and high-altitude (HA) cardiovascular events. To avoid such adverse events, predicting HA cardiorespiratory fitness impairment (HA-CRFi) is clinically important. However, to date, there is insufficient information regarding the prediction of HA-CRFi. In this study, we aimed to formulate a protocol to predict individuals at risk of HA-CRFi. We recruited 246 volunteers who were transported to Lhasa (HA, 3,700 m) from Chengdu (the sea level [SL], <500 m) through an airplane. Physiological parameters at rest and during post-submaximal exercise, as well as cardiorespiratory fitness at HA and SL, were measured. Logistic regression and receiver operating characteristic (ROC) curve analyses were employed to predict HA-CRFi. We analyzed 66 pulmonary vascular function and hypoxia-inducible factor- (HIF-) related polymorphisms associated with HA-CRFi. To increase the prediction accuracy, we used a combination model including physiological parameters and genetic information to predict HA-CRFi. The oxygen saturation (SpO2) of post-submaximal exercise at SL and EPAS1 rs13419896-A and EGLN1 rs508618-G variants were associated with HA-CRFi (SpO2, area under the curve (AUC) = 0.736, cutoff = 95.5%, p < 0.001; EPAS1 A and EGLN1 G, odds ratio [OR] = 12.02, 95% CI = 4.84–29.85, p < 0.001). A combination model including the two risk factors—post-submaximal exercise SpO2 at SL of <95.5% and the presence of EPAS1 rs13419896-A and EGLN1 rs508618-G variants—was significantly more effective and accurate in predicting HA-CRFi (OR = 19.62, 95% CI = 6.42–59.94, p < 0.001). Our study employed a combination of genetic information and the physiological parameters of post-submaximal exercise at SL to predict HA-CRFi. Based on the optimized prediction model, our findings could identify individuals at a high risk of HA-CRFi in an early stage and reduce cardiovascular events.
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Affiliation(s)
- Jie Yang
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Hu Tan
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Mengjia Sun
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Renzheng Chen
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Jihang Zhang
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Chuan Liu
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Yuanqi Yang
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Xiaohan Ding
- Department of Health Care and Geriatrics, The 940th Hospital of Joint Logistics Support Force of PLA, Lanzhou, China
| | - Shiyong Yu
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Wenzhu Gu
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Jingbin Ke
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Yang Shen
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Chen Zhang
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Xubin Gao
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Chun Li
- Department of Ultrasound, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Lan Huang
- Department of Cardiology, The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- *Correspondence: Lan Huang
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6
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Cao JL, Yan JB, Wu JT, Chen ZY. Research progress of sinusoidal endothelial cells in nonalcoholic fatty liver disease. Shijie Huaren Xiaohua Zazhi 2021; 29:1254-1260. [DOI: 10.11569/wcjd.v29.i21.1254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a growing health problem associated with metabolic syndrome. Liver sinusoidal endothelial cells (LSECs) are highly specialized endothelial cells located between the blood and other liver cell types. They are composed of window pores, have high endocytosis, and play an important role in maintaining the overall liver homeostasis. Under pathological conditions, LSECs may be the key event of a variety of chronic liver diseases. In this review, we introduce the unique physiological structure and function of LSECs, summarize the main changes of LSECs in NAFLD (including sinohepatic capillarization, angiogenesis, vasoconstriction, proinflammatory effect, and fibrosis) and their pathogenesis, and discuss the influence of LSECs on the progression of NAFLD, with an aim to demonstrate the potential efficacy of LSECS targeted therapy for NAFLD.
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Affiliation(s)
- Jie-Lu Cao
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou Command, Hangzhou 310006, Zhejiang Province, China
| | - Jun-Bin Yan
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou Command, Hangzhou 310006, Zhejiang Province, China
| | - Jin-Ting Wu
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou Command, Hangzhou 310006, Zhejiang Province, China
| | - Zhi-Yun Chen
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou Command, Hangzhou 310006, Zhejiang Province, China
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7
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Abstract
Liver sinusoidal endothelial cells (LSECs) form the wall of the hepatic sinusoids. Unlike other capillaries, they lack an organized basement membrane and have cytoplasm that is penetrated by open fenestrae, making the hepatic microvascular endothelium discontinuous. LSECs have essential roles in the maintenance of hepatic homeostasis, including regulation of the vascular tone, inflammation and thrombosis, and they are essential for control of the hepatic immune response. On a background of acute or chronic liver injury, LSECs modify their phenotype and negatively affect neighbouring cells and liver disease pathophysiology. This Review describes the main functions and phenotypic dysregulations of LSECs in liver diseases, specifically in the context of acute injury (ischaemia-reperfusion injury, drug-induced liver injury and bacterial and viral infection), chronic liver disease (metabolism-associated liver disease, alcoholic steatohepatitis and chronic hepatotoxic injury) and hepatocellular carcinoma, and provides a comprehensive update of the role of LSECs as therapeutic targets for liver disease. Finally, we discuss the open questions in the field of LSEC pathobiology and future avenues of research.
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8
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Zhao Y, Zeng H, Liu B, He X, Chen JX. Endothelial prolyl hydroxylase 2 is necessary for angiotensin II-mediated renal fibrosis and injury. Am J Physiol Renal Physiol 2020; 319:F345-F357. [PMID: 32715763 DOI: 10.1152/ajprenal.00032.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Angiotensin II (ANG II) is the key contributor to renal fibrosis and injury. The present study investigated the role of endothelium prolyl hydroxylase 2 (PHD2) in ANG II-mediated renal fibrosis and injury. In vitro, endothelial cells (ECs) were isolated from PHD2f/f control [wild-type (WT)] mice or PHD2 EC knockout (PHD2ECKO) mice. In vivo, WT and PHD2ECKO mice were infused with ANG II (1,000 ng·kg-1·min-1) for 28 days. Renal fibrosis, reactive oxygen species (ROS), and iron contents were measured. Knockout of PHD2 resulted in a significant increase in the expression of hypoxia-inducible factor (HIF)-1α and HIF-2α in ECs. Intriguingly, knockout of PHD2 significantly reduced expression of the ANG II type 1 receptor (AT1R) in ECs. WT mice infused with ANG II caused increases in renal fibrosis, ROS formation, and iron contents. ANG II treatment led to a downregulation of PHD1 expression and upregulation of HIF-1α and HIF-2α in the renal cortex and medulla. Knockout of PHD2 in EC blunted ANG II-induced downregulation of PHD1 expression. Furthermore, knockout of PHD2 in ECs attenuated ANG II-induced expression of HIF-1α, HIF-2α, transforming growth factor-β1, p47phox, gp91phox, heme oxygenase-1, and ferroportin. This was accompanied by a significant suppression of renal fibrosis, ROS formation, and iron accumulation. In summary, knockout of endothelial PHD2 suppressed the expression of AT1R in ECs and blunted ANG II-induced downregulation of PHD1 and upregulation of HIF-α in the kidney. Our study, for the first time, demonstrates a necessary role of endothelial PHD2 in ANG II-mediated renal fibrosis and injury.
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Affiliation(s)
- Yongzhen Zhao
- Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - Heng Zeng
- Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - Bo Liu
- Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xiaochen He
- Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jian-Xiong Chen
- Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
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9
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Lafoz E, Ruart M, Anton A, Oncins A, Hernández-Gea V. The Endothelium as a Driver of Liver Fibrosis and Regeneration. Cells 2020; 9:E929. [PMID: 32290100 PMCID: PMC7226820 DOI: 10.3390/cells9040929] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/05/2020] [Accepted: 04/06/2020] [Indexed: 02/07/2023] Open
Abstract
Liver fibrosis is a common feature of sustained liver injury and represents a major public health problem worldwide. Fibrosis is an active research field and discoveries in the last years have contributed to the development of new antifibrotic drugs, although none of them have been approved yet. Liver sinusoidal endothelial cells (LSEC) are highly specialized endothelial cells localized at the interface between the blood and other liver cell types. They lack a basement membrane and display open channels (fenestrae), making them exceptionally permeable. LSEC are the first cells affected by any kind of liver injury orchestrating the liver response to damage. LSEC govern the regenerative process initiation, but aberrant LSEC activation in chronic liver injury induces fibrosis. LSEC are also main players in fibrosis resolution. They maintain liver homeostasis and keep hepatic stellate cell and Kupffer cell quiescence. After sustained hepatic injury, they lose their phenotype and protective properties, promoting angiogenesis and vasoconstriction and contributing to inflammation and fibrosis. Therefore, improving LSEC phenotype is a promising strategy to prevent liver injury progression and complications. This review focuses on changes occurring in LSEC after liver injury and their consequences on fibrosis progression, liver regeneration, and resolution. Finally, a synopsis of the available strategies for LSEC-specific targeting is provided.
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Affiliation(s)
- Erica Lafoz
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
| | - Maria Ruart
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
| | - Aina Anton
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
| | - Anna Oncins
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
| | - Virginia Hernández-Gea
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029 Madrid, Spain
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10
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Hammoutene A, Rautou PE. Role of liver sinusoidal endothelial cells in non-alcoholic fatty liver disease. J Hepatol 2019; 70:1278-1291. [PMID: 30797053 DOI: 10.1016/j.jhep.2019.02.012] [Citation(s) in RCA: 166] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 02/10/2019] [Accepted: 02/13/2019] [Indexed: 12/12/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) and its complications are an expanding health problem associated with the metabolic syndrome. Liver sinusoidal endothelial cells (LSECs) are highly specialized endothelial cells localized at the interface between the blood derived from the gut and the adipose tissue on the one side, and other liver cells on the other side. In physiological conditions, LSECs are gatekeepers of liver homeostasis. LSECs display anti-inflammatory and anti-fibrogenic properties by preventing Kupffer cell and hepatic stellate cell activation and regulating intrahepatic vascular resistance and portal pressure. This review focusses on changes occurring in LSECs in NAFLD and on their consequences on NAFLD progression and complications. Capillarization, namely the loss of LSEC fenestrae, and LSEC dysfunction, namely the loss of the ability of LSECs to generate vasodilator agents in response to increased shear stress both occur early in NAFLD. These LSEC changes favour steatosis development and set the stage for NAFLD progression. At the stage of non-alcoholic steatohepatitis, altered LSECs release inflammatory mediators and contribute to the recruitment of inflammatory cells, thus promoting liver injury and inflammation. Altered LSECs also fail to maintain hepatic stellate cell quiescence and release fibrogenic mediators, including Hedgehog signalling molecules, promoting liver fibrosis. Liver angiogenesis is increased in NAFLD and contributes to liver inflammation and fibrosis, but also to hepatocellular carcinoma development. Thus, improving LSEC health appears to be a promising approach to prevent NAFLD progression and complications.
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Affiliation(s)
- Adel Hammoutene
- Inserm, UMR-970, Paris Cardiovascular Research Center, PARCC, Paris, France; University Paris Descartes, Paris, France
| | - Pierre-Emmanuel Rautou
- Inserm, UMR-970, Paris Cardiovascular Research Center, PARCC, Paris, France; INSERM, UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; University Paris Diderot, Paris, France; Service d'Hépatologie, Centre de Référence des Maladies Vasculaires du Foie, DHU Unity, Pôle des Maladies de l'Appareil Digestif, Hôpital Beaujon, AP-HP, Clichy, France.
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Hypoxia-Inducible Factor Prolyl 4-Hydroxylases and Metabolism. Trends Mol Med 2018; 24:1021-1035. [DOI: 10.1016/j.molmed.2018.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 10/09/2018] [Accepted: 10/10/2018] [Indexed: 12/17/2022]
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12
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The potential role of vascular alterations and subsequent impaired liver blood flow and hepatic hypoxia in the pathophysiology of non-alcoholic steatohepatitis. Med Hypotheses 2018; 122:188-197. [PMID: 30593409 DOI: 10.1016/j.mehy.2018.11.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 11/21/2018] [Indexed: 12/12/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) covers a spectrum of disease ranging from steatosis to steatohepatitis (NASH) and fibrosis, but the underlying pathophysiological mechanisms remain largely unknown. As there is currently no approved pharmacological therapy and the prevalence of NAFLD keeps increasing, understanding of its pathophysiology is crucial. We hypothesise that vascular alterations in early NAFLD play a role in the progression of the disease by inducing an increased intrahepatic vascular resistance and consequently relative hypoxia in the liver. Evidence of the detrimental effects of hypoxia in NAFLD has already been observed in liver surgery, where the outcomes of steatotic livers after ischaemia-reperfusion are worse than in healthy livers, and in obstructive sleep apnoea, which is an independent risk factor of NAFLD. Moreover, early histological damage in NAFLD is situated in the pericentral zone, which is also the first zone to be affected by a decreased oxygen tension because of the unique hepatic vacsular anatomy that causes the pericentral oxygen tension to be the lowest. Angiogenesis is also a characteristic of NAFLD, driven by hypoxia-induced mechanisms, as demonstrated in both animal models and in humans with NAFLD. Relative hypoxia is most probably induced by impaired blood flow to the liver, caused by increased intrahepatic vascular resistance. An increased intrahepatic vascular resistance early in the development of disease has been convincingly demonstrated in several animal models of NAFLD, whereas an increased portal pressure, a consequence of increased intrahepatic vascular resistance, has been proven in patients with NAFLD. Animal studies demonstrated a decreased intrahepatic effect of vasodilators and an increased reactivity to vasoconstrictors that results in an increased intrahepatic vascular resistance, thus the presence of a functional component. Pharmacological products that target vasoregulation can hence improve the intrahepatic vascular resistance and this might prevent or reverse progression of NAFLD, representing an important therapeutic option to study. Some of the drugs currently under evaluation in clinical trials for NASH have interesting properties related to the hepatic vasculature. Some other interesting drugs have been tested in animal models but further study in patients with NAFLD is warranted. In summary, in this paper we summarise the evidence that leads to the hypothesis that an increased intrahepatic vascular resistance and subsequent parenchymal hypoxia in early NAFLD is an important pathophysiological driving mechanism for the progression of the disease.
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