1
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Ando T, Takazawa I, Spencer ZT, Ito R, Tomimori Y, Mikulski Z, Matsumoto K, Ishitani T, Denson LA, Kawakami Y, Kawakami Y, Kitaura J, Ahmed Y, Kawakami T. Ileal Crohn's Disease Exhibits Reduced Activity of Phospholipase C-β3-Dependent Wnt/β-Catenin Signaling Pathway. Cells 2024; 13:986. [PMID: 38891118 PMCID: PMC11171731 DOI: 10.3390/cells13110986] [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: 05/06/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/21/2024] Open
Abstract
Crohn's disease is a chronic, debilitating, inflammatory bowel disease. Here, we report a critical role of phospholipase C-β3 (PLC-β3) in intestinal homeostasis. In PLC-β3-deficient mice, exposure to oral dextran sodium sulfate induced lethality and severe inflammation in the small intestine. The lethality was due to PLC-β3 deficiency in multiple non-hematopoietic cell types. PLC-β3 deficiency resulted in reduced Wnt/β-catenin signaling, which is essential for homeostasis and the regeneration of the intestinal epithelium. PLC-β3 regulated the Wnt/β-catenin pathway in small intestinal epithelial cells (IECs) at transcriptional, epigenetic, and, potentially, protein-protein interaction levels. PLC-β3-deficient IECs were unable to respond to stimulation by R-spondin 1, an enhancer of Wnt/β-catenin signaling. Reduced expression of PLC-β3 and its signature genes was found in biopsies of patients with ileal Crohn's disease. PLC-β regulation of Wnt signaling was evolutionally conserved in Drosophila. Our data indicate that a reduction in PLC-β3-mediated Wnt/β-catenin signaling contributes to the pathogenesis of ileal Crohn's disease.
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Affiliation(s)
- Tomoaki Ando
- Laboratory of Allergic Diseases, Center for Autoimmunity and Inflammation, La Jolla, CA 92037, USA; (T.A.)
- Atopy Research Center, Graduate School of Medicine, Juntendo University, Tokyo 113-8421, Japan
| | - Ikuo Takazawa
- Laboratory of Allergic Diseases, Center for Autoimmunity and Inflammation, La Jolla, CA 92037, USA; (T.A.)
| | - Zachary T. Spencer
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA; (Z.T.S.)
| | - Ryoji Ito
- Laboratory of Allergic Diseases, Center for Autoimmunity and Inflammation, La Jolla, CA 92037, USA; (T.A.)
- Central Institute for Experimental Animals, Kawasaki 210-0821, Kanagawa, Japan
| | - Yoshiaki Tomimori
- Laboratory of Allergic Diseases, Center for Autoimmunity and Inflammation, La Jolla, CA 92037, USA; (T.A.)
| | - Zbigniew Mikulski
- Imaging Facility, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Kenji Matsumoto
- Department of Allergy and Clinical Immunology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
| | - Tohru Ishitani
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-0044, Gunma, Japan
| | - Lee A. Denson
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Yu Kawakami
- Laboratory of Allergic Diseases, Center for Autoimmunity and Inflammation, La Jolla, CA 92037, USA; (T.A.)
| | - Yuko Kawakami
- Laboratory of Allergic Diseases, Center for Autoimmunity and Inflammation, La Jolla, CA 92037, USA; (T.A.)
| | - Jiro Kitaura
- Atopy Research Center, Graduate School of Medicine, Juntendo University, Tokyo 113-8421, Japan
| | - Yashi Ahmed
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA; (Z.T.S.)
| | - Toshiaki Kawakami
- Laboratory of Allergic Diseases, Center for Autoimmunity and Inflammation, La Jolla, CA 92037, USA; (T.A.)
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2
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Liang Y, Luo C, Sun L, Feng T, Yin W, Zhang Y, Mulholland MW, Zhang W, Yin Y. Reduction of specific enterocytes from loss of intestinal LGR4 improves lipid metabolism in mice. Nat Commun 2024; 15:4393. [PMID: 38782937 PMCID: PMC11116434 DOI: 10.1038/s41467-024-48622-5] [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: 01/26/2023] [Accepted: 05/03/2024] [Indexed: 05/25/2024] Open
Abstract
Whether intestinal Leucine-rich repeat containing G-protein-coupled receptor 4 (LGR4) impacts nutrition absorption and energy homeostasis remains unknown. Here, we report that deficiency of Lgr4 (Lgr4iKO) in intestinal epithelium decreased the proportion of enterocytes selective for long-chain fatty acid absorption, leading to reduction in lipid absorption and subsequent improvement in lipid and glucose metabolism. Single-cell RNA sequencing demonstrates the heterogeneity of absorptive enterocytes, with a decrease in enterocytes selective for long-chain fatty acid-absorption and an increase in enterocytes selective for carbohydrate absorption in Lgr4iKO mice. Activation of Notch signaling and concurrent inhibition of Wnt signaling are observed in the transgenes. Associated with these alterations is the substantial reduction in lipid absorption. Decrement in lipid absorption renders Lgr4iKO mice resistant to high fat diet-induced obesity relevant to wild type littermates. Our study thus suggests that targeting intestinal LGR4 is a potential strategy for the intervention of obesity and liver steatosis.
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Affiliation(s)
- Yuan Liang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, 100191, Beijing, China
| | - Chao Luo
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, 100191, Beijing, China
| | - Lijun Sun
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, 100191, Beijing, China
| | - Tiange Feng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, 100191, Beijing, China
| | - Wenzhen Yin
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, 100191, Beijing, China
| | - Yunhua Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, 100191, Beijing, China
| | - Michael W Mulholland
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, 48109-0346, USA
| | - Weizhen Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, 100191, Beijing, China.
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, 48109-0346, USA.
| | - Yue Yin
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, 100191, Beijing, China.
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3
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Filipowska J, Cisneros Z, Leon-Rivera N, Wang P, Kang R, Lu G, Yuan YC, Bhattacharya S, Dhawan S, Garcia-Ocaña A, Kondegowda NG, Vasavada RC. LGR4 is essential for maintaining β-cell homeostasis through suppression of RANK. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.10.593645. [PMID: 38798561 PMCID: PMC11118322 DOI: 10.1101/2024.05.10.593645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Pancreatic β-cell stress contributes to diabetes progression. This study demonstrates that Leucine-rich repeat-containing G-protein-coupled-receptor-4 (LGR4) is critical for maintaining β-cell health and is modulated by stressors. In vitro , Lgr4 knockdown decreases proliferation and survival in rodent β-cells, while overexpression protects against cytokine-induced cell death in rodent and human β-cells. Mechanistically, LGR4 suppresses Receptor Activator of Nuclear Factor Kappa B (NFκB) (RANK) and its subsequent activation of NFκB to protect β-cells. β-cell-specific Lgr4 -conditional knockout (cko) mice exhibit normal glucose homeostasis but increased β-cell death in both sexes and decreased proliferation only in females. Male Lgr4 cko mice under stress display reduced β-cell proliferation and a further increase in β-cell death. Upon aging, both male and female Lgr4 cko mice display impaired β-cell homeostasis, however, only female mice are glucose intolerant with decreased plasma insulin. We show that LGR4 is required for maintaining β-cell health under basal and stress-induced conditions, through suppression of RANK. Teaser LGR4 receptor is critical for maintaining β-cell health under basal and stressed conditions, through suppression of RANK.
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4
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Wizenty J, Müllerke S, Kolesnichenko M, Heuberger J, Lin M, Fischer AS, Mollenkopf HJ, Berger H, Tacke F, Sigal M. Gastric stem cells promote inflammation and gland remodeling in response to Helicobacter pylori via Rspo3-Lgr4 axis. EMBO J 2022; 41:e109996. [PMID: 35767364 PMCID: PMC9251867 DOI: 10.15252/embj.2021109996] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 05/17/2022] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori is a pathogen that colonizes the stomach and causes chronic gastritis. Helicobacter pylori can colonize deep inside gastric glands, triggering increased R‐spondin 3 (Rspo3) signaling. This causes an expansion of the “gland base module,” which consists of self‐renewing stem cells and antimicrobial secretory cells and results in gland hyperplasia. The contribution of Rspo3 receptors Lgr4 and Lgr5 is not well explored. Here, we identified that Lgr4 regulates Lgr5 expression and is required for H. pylori‐induced hyperplasia and inflammation, while Lgr5 alone is not. Using conditional knockout mice, we reveal that R‐spondin signaling via Lgr4 drives proliferation of stem cells and also induces NF‐κB activity in the proliferative stem cells. Upon exposure to H. pylori, the Lgr4‐driven NF‐κB activation is responsible for the expansion of the gland base module and simultaneously enables chemokine expression in stem cells, resulting in gland hyperplasia and neutrophil recruitment. This demonstrates a connection between R‐spondin‐Lgr and NF‐κB signaling that links epithelial stem cell behavior and inflammatory responses to gland‐invading H. pylori.
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Affiliation(s)
- Jonas Wizenty
- Division of Gastroenterology and Hepatology, Medical Department, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
| | - Stefanie Müllerke
- Division of Gastroenterology and Hepatology, Medical Department, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute for Medical Systems Biology (BIMSB), Berlin, Germany
| | - Marina Kolesnichenko
- Division of Gastroenterology, Infectiology and Rheumatology, Medical Department, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Julian Heuberger
- Division of Gastroenterology and Hepatology, Medical Department, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute for Medical Systems Biology (BIMSB), Berlin, Germany
| | - Manqiang Lin
- Division of Gastroenterology and Hepatology, Medical Department, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute for Medical Systems Biology (BIMSB), Berlin, Germany
| | - Anne-Sophie Fischer
- Division of Gastroenterology and Hepatology, Medical Department, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany.,Berlin Institute for Medical Systems Biology (BIMSB), Berlin, Germany
| | - Hans-Joachim Mollenkopf
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Hilmar Berger
- Division of Gastroenterology and Hepatology, Medical Department, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Frank Tacke
- Division of Gastroenterology and Hepatology, Medical Department, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Sigal
- Division of Gastroenterology and Hepatology, Medical Department, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany.,Berlin Institute for Medical Systems Biology (BIMSB), Berlin, Germany
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5
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Cheng Q, Zheng H, Li M, Wang H, Guo X, Zheng Z, Chen C, Liu J, Zhan T, Li Z, Wu H, Han J, Liu L, Tang T, Chen Q, Du L. LGR4 cooperates with PrPc to endow the stemness of colorectal cancer stem cells contributing to tumorigenesis and liver metastasis. Cancer Lett 2022; 540:215725. [PMID: 35561877 DOI: 10.1016/j.canlet.2022.215725] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/20/2022] [Accepted: 05/05/2022] [Indexed: 01/02/2023]
Abstract
Cancer stem cells (CSCs) are a subpopulation of cancer cells that drive tumour progression and metastasis. Anti-CSC strategies represent new targets for cancer therapies. However, CSCs are highly plastic and heterogeneous, making validation and targeting difficult without bona fide markers that define their identity, especially in a clinical setting. Here, we report that a leucine-rich repeat containing G protein-coupled receptor 4 (LGR4) cooperates with CD44 and PrPc; the latter contributes significantly to metastatic capacity and defines the stemness characteristics of colorectal CSCs. CD44+PrPc+LGR4+ cells effectively developed into organoids and, when transplanted, generated orthotopic and metastatic tumours. Importantly, targeting LGR4 and PrPc with lentiviral shRNAs inhibited organoid development and the growth of orthotopic tumours by inhibiting Wnt/β-catenin signalling. Thus, our study offers a novel therapeutic strategy that simultaneously targets CSC stemness and metastatic properties.
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Affiliation(s)
- Qi Cheng
- The State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences. Beijing, 100101, China; University of Chinese Academy of Sciences. Beijing, 100049, China
| | - Hao Zheng
- The State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University. Tianjin, 300071, China; CNBG-Nankai University Joint Research and Development Center, Tianjin, 300071, China
| | - Ming Li
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute. Beijing, 100142, China
| | - Hongyi Wang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute. Beijing, 100142, China
| | - Xiaoxiao Guo
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Center for Quantitative Biology, Peking University. Beijing, 100871, China
| | - Zhibo Zheng
- Department of International Medical Services, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences. Beijing, 100730, China
| | - Chuyan Chen
- Department of International Medical Services, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences. Beijing, 100730, China
| | - Jinming Liu
- The State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University. Tianjin, 300071, China; CNBG-Nankai University Joint Research and Development Center, Tianjin, 300071, China
| | - Tiancheng Zhan
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute. Beijing, 100142, China
| | - Zhaowei Li
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute. Beijing, 100142, China
| | - Hao Wu
- The State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences. Beijing, 100101, China
| | - Jingdong Han
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Center for Quantitative Biology, Peking University. Beijing, 100871, China
| | - Lei Liu
- The State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences. Beijing, 100101, China; Beijing Institute for Stem Cell and Regenerative Medicine. Beijing, 100101, China
| | - Tieshan Tang
- The State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences. Beijing, 100101, China; Beijing Institute for Stem Cell and Regenerative Medicine. Beijing, 100101, China
| | - Quan Chen
- The State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University. Tianjin, 300071, China.
| | - Lei Du
- The State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences. Beijing, 100101, China; Beijing Institute for Stem Cell and Regenerative Medicine. Beijing, 100101, China.
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6
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Walter RJ, Sonnentag SJ, Munoz-Sagredo L, Merkel M, Richert L, Bunert F, Heneka YM, Loustau T, Hodder M, Ridgway RA, Sansom OJ, Mely Y, Rothbauer U, Schmitt M, Orian-Rousseau V. Wnt signaling is boosted during intestinal regeneration by a CD44-positive feedback loop. Cell Death Dis 2022; 13:168. [PMID: 35190527 PMCID: PMC8861016 DOI: 10.1038/s41419-022-04607-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 01/17/2022] [Accepted: 02/04/2022] [Indexed: 12/24/2022]
Abstract
Enhancement of Wnt signaling is fundamental for stem cell function during intestinal regeneration. Molecular modules control Wnt activity by regulating signal transduction. CD44 is such a positive regulator and a Wnt target gene. While highly expressed in intestinal crypts and used as a stem cell marker, its role during intestinal homeostasis and regeneration remains unknown. Here we propose a CD44 positive-feedback loop that boosts Wnt signal transduction, thus impacting intestinal regeneration. Excision of Cd44 in Cd44fl/fl;VillinCreERT2 mice reduced Wnt target gene expression in intestinal crypts and affected stem cell functionality in organoids. Although the integrity of the intestinal epithelium was conserved in mice lacking CD44, they were hypersensitive to dextran sulfate sodium, and showed more severe inflammation and delayed regeneration. We localized the molecular function of CD44 at the Wnt signalosome, and identified novel DVL/CD44 and AXIN/CD44 complexes. CD44 thus promotes optimal Wnt signaling during intestinal regeneration.
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Affiliation(s)
- Romina J Walter
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Steffen J Sonnentag
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Leonel Munoz-Sagredo
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.,Faculty of Medicine, Universidad de Valparaiso, Angamos 655, 2540064, Vina del Mar, Chile
| | - Melanie Merkel
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Ludovic Richert
- UMR 7021 CNRS, Laboratoire de Bioimagerie et Pathologies, Faculté de Pharmacie, 74 route du Rhin, 67401, Illkirch, France
| | - Felix Bunert
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Yvonne M Heneka
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Thomas Loustau
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Michael Hodder
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.,Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow, G61 1QH, UK
| | - Rachel A Ridgway
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.,Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow, G61 1QH, UK
| | - Owen J Sansom
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.,Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow, G61 1QH, UK
| | - Yves Mely
- UMR 7021 CNRS, Laboratoire de Bioimagerie et Pathologies, Faculté de Pharmacie, 74 route du Rhin, 67401, Illkirch, France
| | - Ulrich Rothbauer
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, Markwiesenstrasse 55, 72770, Reutlingen, Germany.,Pharmaceutical Biotechnology, Eberhard Karls University Tuebingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany
| | - Mark Schmitt
- Institute of Pharmacology, University of Marburg, Karl-von-Frisch-Strasse 2, 35043, Marburg, Germany
| | - Véronique Orian-Rousseau
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
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7
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Yang L, Wang J, Gong X, Fan Q, Yang X, Cui Y, Gao X, Li L, Sun X, Li Y, Wang Y. Emerging Roles for LGR4 in Organ Development, Energy Metabolism and Carcinogenesis. Front Genet 2022; 12:728827. [PMID: 35140734 PMCID: PMC8819683 DOI: 10.3389/fgene.2021.728827] [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: 06/22/2021] [Accepted: 12/30/2021] [Indexed: 11/26/2022] Open
Abstract
The leucine-rich repeats containing G protein-coupled receptor 4 (LGR4) belonging to G protein-coupled receptors (GPCRs) family, had various regulatory roles at multiple cellular types and numerous targeting sites, and aberrant LGR4 signaling played crucial roles in diseases and carcinogenesis. On the basis of these facts, LGR4 may become an appealing therapeutic target for the treatment of diseases and tumors. However, a comprehensive investigation of its functions and applications was still lacking. Hence, this paper provided an overview of the molecular characteristics and signaling mechanisms of LGR4, its involvement in multiple organ development and participation in the modulation of immunology related diseases, metabolic diseases, and oxidative stress damage along with cancer progression. Given that GPCRs accounted for almost a third of current clinical drug targets, the in-depth understanding of the sophisticated connections of LGR4 and its ligands would not only enrich their regulatory networks, but also shed new light on designing novel molecular targeted drugs and small molecule blockers for revolutionizing the treatment of various diseases and tumors.
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Affiliation(s)
- Linlin Yang
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
| | - Jing Wang
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
| | - Xiaodi Gong
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
| | - Qiong Fan
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
| | - Xiaoming Yang
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
| | - Yunxia Cui
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
| | - Xiaoyan Gao
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
| | - Lijuan Li
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
| | - Xiao Sun
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
| | - Yuhong Li
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
- *Correspondence: Yuhong Li, ; Yudong Wang,
| | - Yudong Wang
- Department of Gynecological Oncology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Municipal Key Clinical Specialty, Shanghai, China
- Shanghai Key Laboratory of Embryo Original Disease, Shanghai, China
- *Correspondence: Yuhong Li, ; Yudong Wang,
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8
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Challenges and opportunities targeting mechanisms of epithelial injury and recovery in acute intestinal graft-versus-host disease. Mucosal Immunol 2022; 15:605-619. [PMID: 35654837 PMCID: PMC9259481 DOI: 10.1038/s41385-022-00527-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/21/2022] [Accepted: 05/16/2022] [Indexed: 02/04/2023]
Abstract
Despite advances in immunosuppressive prophylaxis and overall supportive care, gastrointestinal (GI) graft-versus-host disease (GVHD) remains a major, lethal side effect after allogeneic hematopoietic stem cell transplantation (allo-HSCT). It has become increasingly clear that the intestinal epithelium, in addition to being a target of transplant-related toxicity and GVHD, plays an important role in the onset of GVHD. Over the last two decades, increased understanding of the epithelial constituents and their microenvironment has led to the development of novel prophylactic and therapeutic interventions, with the potential to protect the intestinal epithelium from GVHD-associated damage and promote its recovery following insult. In this review, we will discuss intestinal epithelial injury and the role of the intestinal epithelium in GVHD pathogenesis. In addition, we will highlight possible approaches to protect the GI tract from damage posttransplant and to stimulate epithelial regeneration, in order to promote intestinal recovery. Combined treatment modalities integrating immunomodulation, epithelial protection, and induction of regeneration may hold the key to unlocking mucosal recovery and optimizing therapy for acute intestinal GVHD.
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9
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Filipowska J, Kondegowda NG, Leon-Rivera N, Dhawan S, Vasavada RC. LGR4, a G Protein-Coupled Receptor With a Systemic Role: From Development to Metabolic Regulation. Front Endocrinol (Lausanne) 2022; 13:867001. [PMID: 35707461 PMCID: PMC9190282 DOI: 10.3389/fendo.2022.867001] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/21/2022] [Indexed: 12/22/2022] Open
Abstract
Leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4/GPR48), a member of the GPCR (G protein-coupled receptors) superfamily, subfamily B, is a common intestinal crypt stem cell marker. It binds R-spondins/Norrin as classical ligands and plays a crucial role in Wnt signaling potentiation. Interaction between LGR4 and R-spondins initiates many Wnt-driven developmental processes, e.g., kidney, eye, or reproductive tract formation, as well as intestinal crypt (Paneth) stem cell pool maintenance. Besides the well-described role of LGR4 in development, several novel functions of this receptor have recently been discovered. In this context, LGR4 was indicated to participate in TGFβ and NFκB signaling regulation in hematopoietic precursors and intestinal cells, respectively, and found to be a new, alternative receptor for RANKL (Receptor Activator of NF kappa B Ligand) in bone cells. LGR4 inhibits the process of osteoclast differentiation, by antagonizing the interaction between RANK (Receptor Activator of NF kappa B) and its ligand-RANKL. It is also known to trigger anti-inflammatory responses in different tissues (liver, intestine, cardiac cells, and skin), serve as a sensor of the circadian clock in the liver, regulate adipogenesis and energy expenditure in adipose tissue and skeletal muscles, respectively. The extracellular domain of LGR4 (LGR4-ECD) has emerged as a potential new therapeutic for osteoporosis and cancer. LGR4 integrates different signaling pathways and regulates various cellular processes vital for maintaining whole-body homeostasis. Yet, the role of LGR4 in many cell types (e.g. pancreatic beta cells) and diseases (e.g., diabetes) remains to be elucidated. Considering the broad spectrum of LGR4 actions, this review aims to discuss both canonical and novel roles of LGR4, with emphasis on emerging research directions focused on this receptor.
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10
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Tan X, Zhang L, Li T, Zhan J, Qiao K, Wu H, Sun S, Huang M, Zhang F, Zhang M, Li C, Li R, Pan H. Lgr4 Regulates Oviductal Epithelial Secretion Through the WNT Signaling Pathway. Front Cell Dev Biol 2021; 9:666303. [PMID: 34631693 PMCID: PMC8497904 DOI: 10.3389/fcell.2021.666303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 08/31/2021] [Indexed: 12/13/2022] Open
Abstract
The WNT signaling pathway plays a crucial role in oviduct/fallopian development. However, the specific physiological processes regulated by the WNT pathway in the fallopian/oviduct function remain obscure. Benefiting from the Lgr4 knockout mouse model, we report the regulation of oviduct epithelial secretion by LGR4. Specifically, the loss of Lgr4 altered the mouse oviduct size and weight, severely reduced the number of oviductal epithelial cells, and ultimately impaired the epithelial secretion. These alterations were mediated by a failure of CTNNB1 protein accumulation in the oviductal epithelial cytoplasm, by the modulation of WNT pathways, and subsequently by a profound change of the gene expression profile of epithelial cells. In addition, selective activation of the WNT pathway triggered the expression of steroidogenic genes, like Cyp11a1 and 3β-Hsd1, through the activation of the transcriptional factor NR5A2 in an oviduct primary cell culture system. As demonstrated, the LGR4 protein modulates a WNT-NR5A2 signaling cascade facilitating epithelial secretory cell maturation and steroidogenesis to safeguard oviduct development and function in mice.
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Affiliation(s)
- Xue Tan
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China
| | - Lingling Zhang
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China
| | - Tianqi Li
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China
| | - Jianmin Zhan
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China
| | - Kun Qiao
- Center for Reproductive Medicine, Tenth People's Hospital of Tongji University, Shanghai, China
| | - Haili Wu
- Shanghai Endangered Species Conservation and Research Centre, Shanghai Zoo, Shanghai, China
| | - Shenfei Sun
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Meina Huang
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China
| | - Fangxi Zhang
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China
| | - Meixing Zhang
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China
| | - Changwei Li
- Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases With Integrated Chinese-Western Medicine, Ruijin Hospital, Shanghai Institute of Traumatology and Orthopedics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Runsheng Li
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China
| | - Hongjie Pan
- National Health Commission (NHC) Key Laboratory of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Pharmacy, Fudan University, Shanghai, China
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11
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Ma X, Yin B, Guo S, Umar T, Liu J, Wu Z, Zhou Q, Zahoor A, Deng G. Enhanced Expression of miR-34a Enhances Escherichia coli Lipopolysaccharide-Mediated Endometritis by Targeting LGR4 to Activate the NF- κB Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:1744754. [PMID: 34504639 PMCID: PMC8422159 DOI: 10.1155/2021/1744754] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 07/11/2021] [Accepted: 08/11/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Persistent endometritis caused by bacterial infections has lethal effects on the reproductive performance of dairy cattle, which compromises animal welfare and delays or prevents pregnancy. The microRNA (miRNA) miR-34 family plays a pivotal role in the inflammatory process; however, the precise mechanism of miR-34a in endometritis has not been thoroughly elucidated to date. METHODS In this study, the endometrium of cows diagnosed with endometritis was harvested for bacterial culture and Gram staining to evaluate bacterial contamination of the uterus. Based on this, a bovine endometrial epithelial cell (BEND) inflammation model and a mouse model stimulated with lipopolysaccharide (LPS) in vitro and in vivo were constructed. Cell viability was assessed by CCK-8, trypan blue staining, and flow cytometry. H&E was applied to histopathological analysis. Immunohistochemical, immunofluorescence, qRT-PCR, and western blot assays were performed to measure the mRNA and protein expression of relevant genes. Online databases, plasmid construction, and dual-luciferase reporter gene assays were used to predict and validate the interaction between miR-34a and its target gene LGR4. Finally, mice were injected vaginally with a local antagomir to validate the role of miR-34a in murine uterine inflammation. RESULTS In this study, we observed that Gram-negative bacteria, represented by Escherichia coli, are the predominant pathogenic agents responsible for the recurrent occurrence of endometritis in dairy cows. Further, miR-34a was found to repress the expression of LGR4 by targeting the 3' untranslated region (3'UTR) of LGR4. miR-34a was upregulated in bovine uterine tissues and bovine endometrial epithelial cells stimulated with LPS. miR-34a induced the release of the proinflammatory cytokines IL-1β, IL-6, and TNF-α by activating the phosphorylation of NF-κB p65. Furthermore, IL-1β upregulated miR-34a transcription and downregulated LGR4 expression in an IL-1β-dependent manner. CONCLUSIONS Taken together, our study confirmed that miR-34a is regulated by IL-1β and suppresses the level of the LGR4 3'UTR, which in turn exacerbates the inflammatory response. Thus, the knockdown of miR-34a might be a new direction for the treatment of endometritis.
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Affiliation(s)
- Xiaofei Ma
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Baoyi Yin
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Shuai Guo
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Talha Umar
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Junfeng Liu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- College of Animal Science, Tarim University, Alar, Xinjiang, China
| | - Zhimin Wu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Qingqing Zhou
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Arshad Zahoor
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Sciences, The University of Agriculture Peshawar, Pakistan
| | - Ganzhen Deng
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
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12
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Zullo KM, Douglas B, Maloney NM, Ji Y, Wei Y, Herbine K, Cohen R, Pastore C, Cramer Z, Wang X, Wei W, Somsouk M, Hung LY, Lengner C, Kohanski MH, Cohen NA, Herbert DR. LINGO3 regulates mucosal tissue regeneration and promotes TFF2 dependent recovery from colitis. Scand J Gastroenterol 2021; 56:791-805. [PMID: 33941035 PMCID: PMC8647134 DOI: 10.1080/00365521.2021.1917650] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Aim: Recovery of damaged mucosal surfaces following inflammatory insult requires diverse regenerative mechanisms that remain poorly defined. Previously, we demonstrated that the reparative actions of Trefoil Factor 3 (TFF3) depend upon the enigmatic receptor, leucine rich repeat and immunoglobulin-like domain containing nogo receptor 2 (LINGO2). This study examined the related orphan receptor LINGO3 in the context of intestinal tissue damage to determine whether LINGO family members are generally important for mucosal wound healing and maintenance of the intestinal stem cell (ISC) compartment needed for turnover of mucosal epithelium.Methods and Results: We find that LINGO3 is broadly expressed on human enterocytes and sparsely on discrete cells within the crypt niche, that contains ISCs. Loss of function studies indicate that LINGO3 is involved in recovery of normal intestinal architecture following dextran sodium sulfate (DSS)-induced colitis, and that LINGO3 is needed for therapeutic action of the long acting TFF2 fusion protein (TFF2-Fc), including a number of signaling pathways critical for cell proliferation and wound repair. LINGO3-TFF2 protein-protein interactions were relatively weak however and LINGO3 was only partially responsible for TFF2 induced MAPK signaling suggesting additional un-identified components of a receptor complex. However, deficiency in either TFF2 or LINGO3 abrogated budding/growth of intestinal organoids and reduced expression of the intestinal ISC gene leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5), indicating homologous roles for these proteins in tissue regeneration, possibly via regulation of ISCs in the crypt niche.Conclusion: We propose that LINGO3 serves a previously unappreciated role in promoting mucosal wound healing.
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Affiliation(s)
- Kelly M. Zullo
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Bonnie Douglas
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Nicole M. Maloney
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Yingbiao Ji
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Yun Wei
- Department of Medicine, Division of Experimental Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Karl Herbine
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Rachel Cohen
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Christopher Pastore
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Zvi Cramer
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Xin Wang
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Wenjie Wei
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19147
| | - Ma Somsouk
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Li Yin Hung
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104,Department of Medicine, Division of Experimental Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Christopher Lengner
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Michael H. Kohanski
- Department of Otorhinolaryngology—Head and Neck Surgery, Perelman School of Medicine at The University of Pennsylvania, Philadelphia, PA 19104,The Corporal Michael J. Crescenz VA Medical Center Surgical Service, Philadelphia, PA 19104
| | - Noam A. Cohen
- Department of Otorhinolaryngology—Head and Neck Surgery, Perelman School of Medicine at The University of Pennsylvania, Philadelphia, PA 19104,The Corporal Michael J. Crescenz VA Medical Center Surgical Service, Philadelphia, PA 19104,Monell Chemical Senses Center, Philadelphia, PA 19104
| | - De’Broski R. Herbert
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104,Department of Medicine, Division of Experimental Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
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13
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The Role of LGR4 (GPR48) in Normal and Cancer Processes. Int J Mol Sci 2021; 22:ijms22094690. [PMID: 33946652 PMCID: PMC8125670 DOI: 10.3390/ijms22094690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 12/13/2022] Open
Abstract
Leucine-rich repeats containing G protein-coupled receptor 4 (LGR4) is a receptor that belongs to the superfamily of G protein-coupled receptors that can be activated by R-spondins (RSPOs), Norrin, circLGR4, and the ligand of the receptor activator of nuclear factor kappa-B (RANKL) ligands to regulate signaling pathways in normal and pathological processes. LGR4 is widely expressed in different tissues where it has multiple functions such as tissue development and maintenance. LGR4 mainly acts through the Wnt/β-catenin pathway to regulate proliferation, survival, and differentiation. In cancer, LGR4 participates in tumor progression, invasion, and metastasis. Furthermore, recent evidence reveals that LGR4 is essential for the regulation of the cancer stem cell population by controlling self-renewal and regulating stem cell properties. This review summarizes the function of LGR4 and its ligands in normal and malignant processes.
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14
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Chen T, Qiao X, Cheng L, Liu M, Deng Y, Zhuo X. LGR4 silence aggravates ischemic injury by modulating mitochondrial function and oxidative stress via ERK signaling pathway in H9c2 cells. J Mol Histol 2021; 52:363-371. [PMID: 33559814 DOI: 10.1007/s10735-021-09957-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 01/18/2021] [Indexed: 11/29/2022]
Abstract
It is reported that LGR4 (leucine-rich repeat domain containing G protein-coupled receptor 4) plays a crucial role in the physiological function of many organs. However, few data are available on the function and mechanism of LGR4 in myocardial ischemia-reperfusion (I/R) injury. The aim of this study was to explore the function and mechanism of LGR4 in I/R injury. We incubated H9c2 cells in simulating ischemia buffer and then re-incubated them in normal culture medium to establish a model of I/R injury in vitro. The expression of LGR4 was evaluated by RT-PCR and western blot. Besides, the cell apoptosis was evaluated by flow cytometric analysis and the content of ROS, SOD, MDA, LDH, CK, ATP, cyt c were detected by special commercial kits. The expression of mitochondrial function-related proteins were detected by western blot. Then, the roles of ERK signaling pathway was determined with TBHQ (ERK activator) treatment. Our data have demonstrated that I/R boosted the expression of LGR4 in H9c2 cells. Knockdown of LGR4 increased the apoptosis rate of H9c2 cells and led to excessed oxidant stress and impaired mitochondrial function by increasing the levels of ROS, MDA, LDH, CK and cyt c and inhibiting SOD activity, ATP production. In addition, LGR4 silence inhibited the activation of ERK pathway. And TBHQ partially reversed the effects of LGR4 knockdown on H9c2 cells. To conclude, our study indicated that LGR4 regulated mitochondrial dysfunction and oxidative stress by ERK signaling pathways, which provides a potential cardiac protective target against I/R.
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Affiliation(s)
- Tao Chen
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Xiangrui Qiao
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Lele Cheng
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Mengping Liu
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Yangyang Deng
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Xiaozhen Zhuo
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, Shaanxi, China.
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15
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Sprangers J, Zaalberg IC, Maurice MM. Organoid-based modeling of intestinal development, regeneration, and repair. Cell Death Differ 2021; 28:95-107. [PMID: 33208888 PMCID: PMC7852609 DOI: 10.1038/s41418-020-00665-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 10/28/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023] Open
Abstract
The intestinal epithelium harbors a remarkable adaptability to undergo injury-induced repair. A key part of the regenerative response is the transient reprogramming of epithelial cells into a fetal-like state, which drives uniform proliferation, tissue remodeling, and subsequent restoration of the homeostatic state. In this review, we discuss how Wnt and YAP signaling pathways control the intestinal repair response and the transitioning of cell states, in comparison with the process of intestinal development. Furthermore, we highlight how organoid-based applications have contributed to the characterization of the mechanistic principles and key players that guide these developmental and regenerative events.
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Affiliation(s)
- Joep Sprangers
- Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
| | - Irene C Zaalberg
- Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
| | - Madelon M Maurice
- Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.
- Oncode Institute, Utrecht, The Netherlands.
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16
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Zhu Y, Cui G, Miyauchi E, Nakanishi Y, Mukohira H, Shimba A, Abe S, Tani-Ichi S, Hara T, Nakase H, Chiba T, Sehara-Fujisawa A, Seno H, Ohno H, Ikuta K. Intestinal epithelial cell-derived IL-15 determines local maintenance and maturation of intra-epithelial lymphocytes in the intestine. Int Immunol 2020; 32:307-319. [PMID: 31875880 DOI: 10.1093/intimm/dxz082] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 12/21/2019] [Indexed: 02/06/2023] Open
Abstract
Interleukin-15 (IL-15) is a cytokine critical for maintenance of intestinal intra-epithelial lymphocytes (IELs), especially CD8αα + IELs (CD8αα IELs). In the intestine, IL-15 is produced by intestinal epithelial cells (IECs), blood vascular endothelial cells (BECs) and hematopoietic cells. However, the precise role of intestinal IL-15 on IELs is still unknown. To address the question, we generated two kinds of IL-15 conditional knockout (IL-15cKO) mice: villin-Cre (Vil-Cre) and Tie2-Cre IL-15cKO mice. IEC-derived IL-15 was specifically deleted in Vil-Cre IL-15cKO mice, whereas IL-15 produced by BECs and hematopoietic cells was deleted in Tie2-Cre IL-15cKO mice. The cell number and frequency of CD8αα IELs and NK IELs were significantly reduced in Vil-Cre IL-15cKO mice. By contrast, CD8αα IELs were unchanged in Tie2-Cre IL-15cKO mice, indicating that IL-15 produced by BECs and hematopoietic cells is dispensable for CD8αα IELs. Expression of an anti-apoptotic factor, Bcl-2, was decreased, whereas Fas expression was increased in CD8αα IELs of Vil-Cre IL-15cKO mice. Forced expression of Bcl-2 by a Bcl-2 transgene partially restored CD8αα IELs in Vil-Cre IL-15cKO mice, suggesting that some IL-15 signal other than Bcl-2 is required for maintenance of CD8αα IELs. Furthermore, granzyme B production was reduced, whereas PD-1 expression was increased in CD8αα IELs of Vil-Cre IL-15cKO mice. These results collectively suggested that IEC-derived IL-15 is essential for homeostasis of IELs by promoting their survival and functional maturation.
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Affiliation(s)
- Yuanbo Zhu
- Laboratory of Immune Regulation, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Guangwei Cui
- Laboratory of Immune Regulation, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Eiji Miyauchi
- Laboratory for Intestinal Ecosystem, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | | | - Hisa Mukohira
- Laboratory of Immune Regulation, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akihiro Shimba
- Laboratory of Immune Regulation, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Shinya Abe
- Laboratory of Immune Regulation, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shizue Tani-Ichi
- Laboratory of Immune Regulation, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,Laboratory of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takahiro Hara
- Laboratory of Immune Regulation, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Hiroshi Nakase
- Department of Gastroenterology and Hepatology, Sapporo Medical University, School of Medicine, Sapporo, Japan
| | | | - Atsuko Sehara-Fujisawa
- Laboratory of Tissue Stem Cell Biology, Department of Regeneration Science and Engineering, Institute of Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | | | - Hiroshi Ohno
- Laboratory for Intestinal Ecosystem, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.,Division of Immunobiology, Department of Medical Life Science, Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan.,Kanagawa Institute of Industrial Science and Technology, Kanagawa, Japan
| | - Koichi Ikuta
- Laboratory of Immune Regulation, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
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17
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Wei G, Gao N, Chen J, Fan L, Zeng Z, Gao G, Li L, Fang G, Hu K, Pang X, Fan HY, Clevers H, Liu M, Zhang X, Li D. Erk and MAPK signaling is essential for intestinal development through Wnt pathway modulation. Development 2020; 147:dev.185678. [PMID: 32747435 DOI: 10.1242/dev.185678] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 07/23/2020] [Indexed: 12/28/2022]
Abstract
Homeostasis of intestinal stem cells (ISCs) is maintained by the orchestration of niche factors and intrinsic signaling networks. Here, we have found that deletion of Erk1 and Erk2 (Erk1/2) in intestinal epithelial cells at embryonic stages resulted in an unexpected increase in cell proliferation and migration, expansion of ISCs, and formation of polyp-like structures, leading to postnatal death. Deficiency of epithelial Erk1/2 results in defects in secretory cell differentiation as well as impaired mesenchymal cell proliferation and maturation. Deletion of Erk1/2 strongly activated Wnt signaling through both cell-autonomous and non-autonomous mechanisms. In epithelial cells, Erk1/2 depletion resulted in loss of feedback regulation, leading to Ras/Raf cascade activation that transactivated Akt activity to stimulate the mTor and Wnt/β-catenin pathways. Moreover, Erk1/2 deficiency reduced the levels of Indian hedgehog and the expression of downstream pathway components, including mesenchymal Bmp4 - a Wnt suppressor in intestines. Inhibition of mTor signaling by rapamycin partially rescued Erk1/2 depletion-induced intestinal defects and significantly prolonged the lifespan of mutant mice. These data demonstrate that Erk/Mapk signaling functions as a key modulator of Wnt signaling through coordination of epithelial-mesenchymal interactions during intestinal development.
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Affiliation(s)
- Gaigai Wei
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Na Gao
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jiwei Chen
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Lingling Fan
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zhiyang Zeng
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Ganglong Gao
- Fengxian Hospital affiliated to Southern Medical University, Shanghai 201499, China
| | - Liang Li
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Guojiu Fang
- Fengxian Hospital affiliated to Southern Medical University, Shanghai 201499, China
| | - Kewen Hu
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Xiufeng Pang
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Heng-Yu Fan
- Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Hans Clevers
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), Uppsalalaan 8, Utrecht 3584 CT, The Netherlands
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Xueli Zhang
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China .,Fengxian Hospital affiliated to Southern Medical University, Shanghai 201499, China
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, Joint Research Center for Translational Medicine, ECNU-Fengxian Hospital, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
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18
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Greicius G, Virshup DM. Stromal control of intestinal development and the stem cell niche. Differentiation 2019; 108:8-16. [DOI: 10.1016/j.diff.2019.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 01/07/2019] [Indexed: 02/07/2023]
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19
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Li Z, Liu S, Lou J, Mulholland M, Zhang W. LGR4 protects hepatocytes from injury in mouse. Am J Physiol Gastrointest Liver Physiol 2019; 316:G123-G131. [PMID: 30406697 PMCID: PMC6383381 DOI: 10.1152/ajpgi.00056.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Leucine-rich repeat G protein-coupled receptors (LGRs) and their endogenous ligands R-spondin1-4 (Rspo) are critical in embryonic development and in maintenance of stem cells. The functions of the Rspo-LGR system in differentiated cells remain uncharacterized. In this study, the expression profiles of LGRs and Rspos were characterized in mature hepatocytes. A liver-specific knockout of LGR4 in mouse was generated and used to study hepatic ischemia/reperfusion-induced injury (HIRI) as well as lipopolysaccharide/ D- galactosamine (LPS/D-Gal)-induced liver injury. We have demonstrated that, in adult liver, LGR4 is expressed in hepatocytes and responds to Rspo1 with internalization. Rspo1 is responsive to various nutritional states and to mTOR signaling. Activation of LGR4 by Rspo1 significantly reduced tumor necrosis factor-α (TNFα)-induced cell death, and levels of NF-κB-p65 and caspase-3 in cultured hepatocytes. Knockdown of hepatic LGR4 rendered hepatocytes more vulnerable to TNFα-induced damage in cultured primary cells and in the setting of HIRI and LPS/D-Gal-induced liver injury. Rspo1 potentiated both basal and Wnt3a-induced stabilization of β-catenin. Disruption of β-catenin signaling reversed the protective effects of Rspo1 on TNFα-induced hepatocyte toxicity. LGR4 knockdown increased nuclear translocation of NF-κB-p65 in response to acute injury. Overexpression of IKKβ attenuated the protective effects of Rspo1 on TNFα-induced cell death. In conclusion, the Rspo1-LGR4 system represents a novel pathway for cytoprotection and modulation of stress-induced tissue damage. NEW & NOTEWORTHY Functional LGR4 is present in mature hepatocytes. R-spodin1 protects hepatocytes from tumor necrosis factor-α-induced cell death. Liver-specific knockdown of LGR4 renders liver more susceptible to acute injury. LGR4 protects hepatocytes from injury by inhibition of NF-κB signaling.
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Affiliation(s)
- Ziru Li
- 1Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Shiying Liu
- 2Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
| | - Jianing Lou
- 3Department of Stomatology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Michael Mulholland
- 1Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Weizhen Zhang
- 1Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan,2Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
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20
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PDGFRα+ pericryptal stromal cells are the critical source of Wnts and RSPO3 for murine intestinal stem cells in vivo. Proc Natl Acad Sci U S A 2018; 115:E3173-E3181. [PMID: 29559533 PMCID: PMC5889626 DOI: 10.1073/pnas.1713510115] [Citation(s) in RCA: 200] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Tissue stem cells in vivo reside in highly structured niches that provide signals for proliferation and differentiation. Understanding the role of the niche requires identifying the key cell types that provide these regulators. In the intestine, R-spondins and Wnts are essential regulators of the stem-cell niche. Here we identify subepithelial myofibroblasts of the PDGF receptor α lineage as the specific stromal cell type that secretes these ligands. These data demonstrate the close interaction between epithelial stem cells and the underlying regulatory stroma niche and provide insights into both normal homeostasis and tissue recovery after injury. Wnts and R-spondins (RSPOs) support intestinal homeostasis by regulating crypt cell proliferation and differentiation. Ex vivo, Wnts secreted by Paneth cells in organoids can regulate the proliferation and differentiation of Lgr5-expressing intestinal stem cells. However, in vivo, Paneth cell and indeed all epithelial Wnt production is completely dispensable, and the cellular source of Wnts and RSPOs that maintain the intestinal stem-cell niche is not known. Here we investigated both the source and the functional role of stromal Wnts and RSPO3 in regulation of intestinal homeostasis. RSPO3 is highly expressed in pericryptal myofibroblasts in the lamina propria and is several orders of magnitude more potent than RSPO1 in stimulating both Wnt/β-catenin signaling and organoid growth. Stromal Rspo3 ablation ex vivo resulted in markedly decreased organoid growth that was rescued by exogenous RSPO3 protein. Pdgf receptor alpha (PdgfRα) is known to be expressed in pericryptal myofibroblasts. We therefore evaluated if PdgfRα identified the key stromal niche cells. In vivo, Porcn excision in PdgfRα+ cells blocked intestinal crypt formation, demonstrating that Wnt production in the stroma is both necessary and sufficient to support the intestinal stem-cell niche. Mice with Rspo3 excision in the PdgfRα+ cells had decreased intestinal crypt Wnt/β-catenin signaling and Paneth cell differentiation and were hypersensitive when stressed with dextran sodium sulfate. The data support a model of the intestinal stem-cell niche regulated by both Wnts and RSPO3 supplied predominantly by stromal pericryptal myofibroblasts marked by PdgfRα.
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21
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Yue Z, Yuan Z, Zeng L, Wang Y, Lai L, Li J, Sun P, Xue X, Qi J, Yang Z, Zheng Y, Fang Y, Li D, Siwko S, Li Y, Luo J, Liu M. LGR4 modulates breast cancer initiation, metastasis, and cancer stem cells. FASEB J 2017; 32:2422-2437. [PMID: 29269400 DOI: 10.1096/fj.201700897r] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The fourth member of the leucine-rich repeat-containing GPCR family (LGR4, frequently referred to as GPR48) and its cognate ligands, R-spondins (RSPOs) play crucial roles in the development of multiple organs as well as the survival of adult stem cells by activation of canonical Wnt signaling. Wnt/β-catenin signaling acts to regulate breast cancer; however, the molecular mechanisms determining its spatiotemporal regulation are largely unknown. In this study, we identified LGR4 as a master controller of Wnt/β-catenin signaling-mediated breast cancer tumorigenesis, metastasis, and cancer stem cell (CSC) maintenance. LGR4 expression in breast tumors correlated with poor prognosis. Either Lgr4 haploinsufficiency or mammary-specific deletion inhibited mouse mammary tumor virus (MMTV)- PyMT- and MMTV- Wnt1-driven mammary tumorigenesis and metastasis. Moreover, LGR4 down-regulation decreased in vitro migration and in vivo xenograft tumor growth and lung metastasis. Furthermore, Lgr4 deletion in MMTV- Wnt1 tumor cells or knockdown in human breast cancer cells decreased the number of functional CSCs by ∼90%. Canonical Wnt signaling was impaired in LGR4-deficient breast cancer cells, and LGR4 knockdown resulted in increased E-cadherin and decreased expression of N-cadherin and snail transcription factor -2 ( SNAI2) (also called SLUG), implicating LGR4 in regulation of epithelial-mesenchymal transition. Our findings support a crucial role of the Wnt signaling component LGR4 in breast cancer initiation, metastasis, and breast CSCs.-Yue, Z., Yuan, Z., Zeng, L., Wang, Y., Lai, L., Li, J., Sun, P., Xue, X., Qi, J., Yang, Z., Zheng, Y., Fang, Y., Li, D., Siwko, S., Li, Y., Luo, J., Liu, M. LGR4 modulates breast cancer initiation, metastasis, and cancer stem cells.
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Affiliation(s)
- Zhiying Yue
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Zengjin Yuan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Li Zeng
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.,Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
| | - Ying Wang
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
| | - Li Lai
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
| | - Jing Li
- East China Normal University Joint Center for Translational Medicine, Shanghai Fengxian District Central Hospital, Shanghai, China
| | - Peng Sun
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Xiwen Xue
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Junyi Qi
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Zhengfeng Yang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Yansen Zheng
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Yuanzhang Fang
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Stefan Siwko
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
| | - Yi Li
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Jian Luo
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.,Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
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22
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Zhou M, Guo S, Yuan L, Zhang Y, Zhang M, Chen H, Lu M, Yang J, Ma J. Blockade of LGR4 inhibits proliferation and odonto/osteogenic differentiation of stem cells from apical papillae. J Mol Histol 2017; 48:389-401. [PMID: 28986711 DOI: 10.1007/s10735-017-9737-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 09/20/2017] [Indexed: 01/01/2023]
Abstract
During tooth root development, stem cells from apical papillae (SCAPs) are indispensable, and their abilities of proliferation, migration and odontoblast differentiation are linked to root formation. Leucine-rich repeat-containing GPCR 4 (LGR4) modulates the biological processes of proliferation and differentiation in multiple stem cells. In this study, we showed that LGR4 is expressed in all odontoblast cell lineage cells and Hertwig's epithelial root sheath (HERS) during the mouse root formation in vivo. In vitro we determined that LGR4 is involved in the Wnt/β-catenin signaling pathway regulating proliferation and odonto/osteogenic differentiation of SCAPs. Quantitative reverse-transcription PCR (qRT-PCR) confirmed that LGR4 is expressed during odontogenic differentiation of SCAPs. CCK8 assays and in vitro scratch tests, together with cell cycle flow cytometric analysis, demonstrated that downregulation of LGR4 inhibited SCAPs proliferation, delayed migration and arrested cell cycle progression at the S and G2/M phases. ALP staining revealed that blockade of LGR4 decreased ALP activity. QRT-PCR and Western blot analysis demonstrated that LGR4 silencing reduced the expression of odonto/osteogenic markers (RUNX2, OSX, OPN, OCN and DSPP). Further Western blot and immunofluorescence studies clarified that inhibition of LGR4 disrupted β-catenin stabilization. Taken together, downregulation of LGR4 gene expression inhibited SCAPs proliferation, migration and odonto/osteogenic differentiation by blocking the Wnt/β-catenin signaling pathway. These results indicate that LGR4 might play a vital role in SCAPs proliferation and odontoblastic differentiation.
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Affiliation(s)
- Meng Zhou
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu, 210029, China.,Department of Oral and Maxillofacial Surgery, Xuzhou Stomatological Hospital, Xuzhou, China
| | - Shuyu Guo
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Lichan Yuan
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Yuxin Zhang
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Mengnan Zhang
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Huimin Chen
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Mengting Lu
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Jianrong Yang
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu, 210029, China.
| | - Junqing Ma
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu, 210029, China.
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23
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Abstract
Leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4) is produced in a broad spectrum of mouse embryonic and adult tissues and its deficiency results in embryonal or perinatal lethality. The LGR4 function was mainly related to its potentiation of canonical Wnt signaling; however, several recent studies associate LGR4 with additional signaling pathways. To obtain a suitable tool for studying the signaling properties of Lgr4, we generated a tagged variant of the Lgr4 receptor using gene targeting in the mouse oocyte. The modified Lgr4 allele expresses the Lgr4 protein fused with a triple hemagglutinin (3HA) tag located at the extracellular part of the protein. The allele is fully functional, enabling tracking of Lgr4 expression in the mouse tissues. We also show that via surface labeling, the 3HA tag allows direct isolation and analysis of living Lgr4-positive cells obtained from the small intestinal crypts. Finally, the HA tag-specific antibody can be employed to characterize the biochemical features of Lgr4 and to identify possible biding partners of the protein in cells derived from various mouse tissues.
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24
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Reelin protects from colon pathology by maintaining the intestinal barrier integrity and repressing tumorigenic genes. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2126-2134. [PMID: 28572005 DOI: 10.1016/j.bbadis.2017.05.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 05/15/2017] [Accepted: 05/29/2017] [Indexed: 12/17/2022]
Abstract
We previously reported that reelin, an extracellular matrix protein first known for its key role in neuronal migration, reduces the susceptibility to dextran sulphate sodium (DSS)-colitis. The aim of the current study was to determine whether reelin protects from colorectal cancer and how reelin defends from colon pathology. In the colon of wild-type and of mice lacking reelin (reeler mice) we have analysed the: i) epithelium cell renewal processes, ii) morphology, iii) Sox9, Cdx2, Smad5, Cyclin D1, IL-6 and IFNγ mRNA abundance in DSS-treated and untreated mice, and iv) development of azoxymethane/DSS-induced colorectal cancer, using histological and real time-PCR methodologies. The reeler mutation increases colitis-associated tumorigenesis, with increased tumours number and size. It also impairs the intestinal barrier because it reduces cell proliferation, migration, differentiation and apoptosis; decreases the number and maturation of goblet cells, and expands the intercellular space of the desmosomes. The intestinal barrier impairment might explain the increased susceptibility to colon pathology exhibited by the reeler mice and is at least mediated by the down-regulation of Sox9 and Cdx2. In response to DSS-colitis, the reeler colon increases the mRNA abundance of IL-6, Smad5 and Cyclin D1 and decreases that of IFNγ, conditions that might result in the increased colitis-associated tumorigenesis found in the reeler mice. In conclusion, the results highlight a role for reelin in maintaining intestinal epithelial cell homeostasis and providing resistance against colon pathology.
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25
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Cong F, Wu N, Tian X, Fan J, Liu J, Song T, Fu H. MicroRNA-34c promotes osteoclast differentiation through targeting LGR4. Gene 2017; 610:1-8. [PMID: 28130056 DOI: 10.1016/j.gene.2017.01.028] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 01/08/2023]
Abstract
MicroRNAs have emerged as important regulators of osteoclast differentiation in recent years. Of these, miR-34c has been reported to play an important role in bone development. However, its role and the underlying mechanism in osteoclast differentiation remains poorly understood. In this study, we aimed to investigate the precise role and molecular mechanism of miR-34c in osteoclast differentiation. We found an obvious increase in miR-34c expression during osteoclast differentiation in osteoclast precursors induced by receptor activator of nuclear factor κB (NF-κB) ligand and macrophage colony-stimulating factor in vitro. Further experiments showed that overexpression of miR-34c significantly promoted osteoclast differentiation while suppression of miR-34c showed the opposite effect. Interestingly, bioinformatics analysis and dual-luciferase reporter assays showed that miR-34c targets the 3'-untranslated region of leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4). The expression of LGR4 was regulated by miR-34c in osteoclasts. Moreover, miR-34c regulated NF-κB and glycogen synthase kinase 3-β signaling during osteoclast differentiation. Overexpression of LGR4 partially reversed the promoting effect of miR-34c overexpression on osteoclast differentiation. Taken together, our study suggests that miR-34c contributes to osteoclast differentiation by targeting LGR4, providing novel insights into understanding the molecular mechanism underlying osteoclast differentiation.
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Affiliation(s)
- Fei Cong
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Na Wu
- Department of Dermatology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, China
| | - Xiaoning Tian
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China.
| | - Jinzhu Fan
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Jian Liu
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Tao Song
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Hua Fu
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
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26
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Xu P, Dang Y, Wang L, Liu X, Ren X, Gu J, Liu M, Dai X, Ye X. Lgr4 is crucial for skin carcinogenesis by regulating MEK/ERK and Wnt/β-catenin signaling pathways. Cancer Lett 2016; 383:161-170. [PMID: 27693558 DOI: 10.1016/j.canlet.2016.09.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/07/2016] [Accepted: 09/08/2016] [Indexed: 11/30/2022]
Abstract
Lgr4 is a member of the leucine-rich, G protein-coupled receptor family of proteins, and has recently been shown to augment Wnt/β-catenin signaling via binding to Wnt agonists R-spondins. It plays an important role in skin development, but its involvement in skin tumorigenesis is unclear. Here, we report that mice deficient for Lgr4 are resistant to 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced keratinocyte proliferation and papilloma formation. We show that TPA treatment activates MEK1, ERK1/2 and downstream effector AP-1 in wild-type (WT) epidermal cells and mice, but not in cells or mice where Lgr4 is depleted. Wnt/β-catenin signaling is also dramatically activated by TPA treatment, and this activation is abolished when Lgr4 is deleted. We provide evidences that blocking both MEK1/ERK1/2 and Wnt/β-catenin pathways prevents TPA-induced increase in the expression of Ccnd1 (cyclin D1), a known Wnt/β-catenin target gene, and that the activation of MEK1/ERK1/2 pathway lies upstream of Wnt/β-catenin signal pathway. Collectively, our findings identify Lgr4 as a critical positive factor for skin tumorigenesis by mediating the activation of MEK1/ERK1/2 and Wnt/β-catenin pathways.
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Affiliation(s)
- Peng Xu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Science and School of Life Science, East China Normal University, Shanghai 200241, China
| | - Yongyan Dang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Science and School of Life Science, East China Normal University, Shanghai 200241, China
| | - Luyang Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Science and School of Life Science, East China Normal University, Shanghai 200241, China
| | - Xia Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Science and School of Life Science, East China Normal University, Shanghai 200241, China
| | - Xiaolin Ren
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Science and School of Life Science, East China Normal University, Shanghai 200241, China
| | - Jun Gu
- Department of Dermatology, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 200433, China
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Science and School of Life Science, East China Normal University, Shanghai 200241, China
| | - Xing Dai
- Department of Biological Chemistry, University of California, D250 Med Sci I, Irvine, CA 92697-1700, USA.
| | - Xiyun Ye
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Science and School of Life Science, East China Normal University, Shanghai 200241, China.
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27
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Karin M, Clevers H. Reparative inflammation takes charge of tissue regeneration. Nature 2016; 529:307-15. [PMID: 26791721 DOI: 10.1038/nature17039] [Citation(s) in RCA: 503] [Impact Index Per Article: 62.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 12/07/2015] [Indexed: 02/08/2023]
Abstract
Inflammation underlies many chronic and degenerative diseases, but it also mitigates infections, clears damaged cells and initiates tissue repair. Many of the mechanisms that link inflammation to damage repair and regeneration in mammals are conserved in lower organisms, indicating that it is an evolutionarily important process. Recent insights have shed light on the cellular and molecular processes through which conventional inflammatory cytokines and Wnt factors control mammalian tissue repair and regeneration. This is particularly important for regeneration in the gastrointestinal system, especially for intestine and liver tissues in which aberrant and deregulated repair results in severe pathologies.
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Affiliation(s)
- Michael Karin
- Laboratory of Gene Regulation and Signal Transduction, Departments of Pharmacology and Pathology, Moores Cancer Center, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, California 92093-0636, USA
| | - Hans Clevers
- Princess Máxima Center and Hubrecht Institute, Uppsalalaan 8, 3584 CR Utrecht, the Netherlands.,University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
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28
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Guan Y, Zhang L, Li X, Zhang X, Liu S, Gao N, Li L, Gao G, Wei G, Chen Z, Zheng Y, Ma X, Siwko S, Chen JL, Liu M, Li D. Repression of Mammalian Target of Rapamycin Complex 1 Inhibits Intestinal Regeneration in Acute Inflammatory Bowel Disease Models. THE JOURNAL OF IMMUNOLOGY 2015; 195:339-46. [PMID: 26026060 DOI: 10.4049/jimmunol.1303356] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 05/04/2015] [Indexed: 12/21/2022]
Abstract
The mammalian target of rapamycin (mTOR) signaling pathway integrates environmental cues to regulate cell growth and survival through various mechanisms. However, how mTORC1 responds to acute inflammatory signals to regulate bowel regeneration is still obscure. In this study, we investigated the role of mTORC1 in acute inflammatory bowel disease. Inhibition of mTORC1 activity by rapamycin treatment or haploinsufficiency of Rheb through genetic modification in mice impaired intestinal cell proliferation and induced cell apoptosis, leading to high mortality in dextran sodium sulfate- and 2,4,6-trinitrobenzene sulfonic acid-induced colitis models. Through bone marrow transplantation, we found that mTORC1 in nonhematopoietic cells played a major role in protecting mice from colitis. Reactivation of mTORC1 activity by amino acids had a positive therapeutic effect in mTORC1-deficient Rheb(+/-) mice. Mechanistically, mTORC1 mediated IL-6-induced Stat3 activation in intestinal epithelial cells to stimulate the expression of downstream targets essential for cell proliferation and tissue regeneration. Therefore, mTORC1 signaling critically protects against inflammatory bowel disease through modulation of inflammation-induced Stat3 activity. As mTORC1 is an important therapeutic target for multiple diseases, our findings will have important implications for the clinical usage of mTORC1 inhibitors in patients with acute inflammatory bowel disease.
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Affiliation(s)
- Yuting Guan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Long Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Xia Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Xinyan Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Shijie Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Na Gao
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Liang Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Ganglong Gao
- Fengxian Hospital, Southern Medical University, Shanghai 201499, China; and
| | - Gaigai Wei
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zhaohua Chen
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Yansen Zheng
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Xueyun Ma
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Stefan Siwko
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030
| | - Jin-Lian Chen
- Fengxian Hospital, Southern Medical University, Shanghai 201499, China; and
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China; Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China;
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Li Z, Zhang W, Mulholland MW. LGR4 and Its Role in Intestinal Protection and Energy Metabolism. Front Endocrinol (Lausanne) 2015; 6:131. [PMID: 26379625 PMCID: PMC4548225 DOI: 10.3389/fendo.2015.00131] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/10/2015] [Indexed: 01/04/2023] Open
Abstract
Leucine-rich repeat-containing G protein-coupled receptors were identified by the unique nature of their long leucine-rich repeat extracellular domains. Distinct from classical G protein-coupled receptors which act via G proteins, LGR4 functions mainly through Wnt/β-catenin signaling to regulate cell proliferation, differentiation, and adult stem cell homeostasis. LGR4 is widely expressed in tissues ranging from the reproductive system, urinary system, sensory organs, digestive system, and the central nervous system, indicating LGR4 may have multiple functions in development. Here, we focus on the digestive system by reviewing its effects on crypt cells differentiation and stem cells maintenance, which are important for cell regeneration after injury. Through effects on Wnt/β-catenin signaling and cell proliferation, LGR4 and its endogenous ligands, R-spondins, are involved in colon tumorigenesis. LGR4 also contributes to regulation of energy metabolism, including food intake, energy expenditure, and lipid metabolism, as well as pancreatic β-cell proliferation and insulin secretion. This review summarizes the identification of LGR4, its endogenous ligand, ligand-receptor binding and intracellular signaling. Physiological functions include intestinal development and energy metabolism. The potential effects of LGR4 and its ligand in the treatment of inflammatory bowel disease, chemoradiotherapy-induced gut damage, colorectal cancer, and diabetes are also discussed.
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Affiliation(s)
- Ziru Li
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Weizhen Zhang
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, USA
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
- *Correspondence: Weizhen Zhang, 4618B, MSII, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA; Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing 100191, China, ; Michael W. Mulholland, 1500 East Medical Center Drive, 2101 Taubman Center SPC 5346, Ann Arbor, MI 48109, USA,
| | - Michael W. Mulholland
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, USA
- *Correspondence: Weizhen Zhang, 4618B, MSII, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA; Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing 100191, China, ; Michael W. Mulholland, 1500 East Medical Center Drive, 2101 Taubman Center SPC 5346, Ann Arbor, MI 48109, USA,
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Luo W, Rodriguez M, Valdez JM, Zhu X, Tan K, Li D, Siwko S, Xin L, Liu M. Lgr4 is a key regulator of prostate development and prostate stem cell differentiation. Stem Cells 2014; 31:2492-505. [PMID: 23897697 DOI: 10.1002/stem.1484] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/04/2013] [Accepted: 06/21/2013] [Indexed: 12/31/2022]
Abstract
Mechanisms modulating prostate cell fate determination remain unexplored. The leucine-rich repeat containing G-protein-coupled receptors (Lgr) have been identified as important stem cell markers in various tissues. Here, we investigated the roles of Lgr4/Gpr48 in prostate stem cells (PSCs) and development. Lgr4 was ubiquitously expressed during early prostate development prior to lineage specification, with adult expression restricted to a few basal cells (principally Lin(-)Sca1(+)CD49f(+)). Lgr4(-/-) mice had compromised branching morphogenesis and delayed epithelial differentiation, leading to decreased prostate size and impaired luminal cell function. In vitro prostate sphere culture revealed that Lgr4(-/-) Lin(-)/Sca1(+)/CD49f(+) cells failed to generate p63(low) cells, indicating a differentiation deficiency. Furthermore, Lgr4 ablation arrested PSC differentiation of in vivo kidney capsule prostate grafts, suggesting that Lgr4 modulates PSC properties independent of hormonal and mesenchymal effects. Analysis of neonatal prostates and prostate spheres revealed a decrease in Wnt, Sonic Hedgehog, and Notch1 expression in Lgr4(-/-) cells. Lgr4 loss blocked differentiation of prostate sphere p63(hi) cells to p63(low). Treatment with exogenous Sonic Hedgehog partially restored the differentiation of p63(hi) cells in Lgr4(-/-) spheres. Taken together, our data revealed the roles of Lgr4 in early prostate development and in stem cell differentiation through regulation of the Wnt, Notch, and Sonic Hedgehog signaling pathways.
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Affiliation(s)
- Weijia Luo
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, TexasA&M University Health Science Center, Houston, Texas, USA
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Pan H, Cui H, Liu S, Qian Y, Wu H, Li L, Guan Y, Guan X, Zhang L, Fan HY, Ma Y, Li R, Liu M, Li D. Lgr4 gene regulates corpus luteum maturation through modulation of the WNT-mediated EGFR-ERK signaling pathway. Endocrinology 2014; 155:3624-37. [PMID: 24877628 DOI: 10.1210/en.2013-2183] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Luteal-phase insufficiency is one of the major causes of female infertility, but the molecular mechanisms are still largely unknown. Here we found that disruption of Lgr4/Gpr48, the newly identified receptor for R-spondins, greatly reduced female fertility in mice. The expression of Lgr4 was induced specifically in granulosa-lutein cells during luteinization. In Lgr4-deficient female mice, the estrous cycle was prolonged and serum progesterone levels were dramatically downregulated. In Lgr4(-/-) corpora lutea, the expression of key enzymes for steroidogenesis as well as common luteal marker genes was significantly decreased. Additionally, the activity of epidermal growth factor receptor (EGFR)-ERK signaling was attenuated in Lgr4(-/-) granulosa-lutein cells. We found that the maturation of Lgr4(-/-) cells was impaired in cultured primary granulosa cells, but the defect was partially rescued by reactivation of EGFR signaling by heparin-binding EGF-like growth factor treatment. We found that the expression of wingless-type MMTV integration site family (WNT)/catenin (cadherin associated protein), beta 1 (CTNNB1) downstream targets, including matrix metalloproteinase 9, which is a critical matrix metalloproteinase for activation of EGF-like factors, was significantly downregulated in Lgr4(-/-) ovaries. Matrix metalloproteinase 9 inhibitor treatment attenuated human chorionic gonadotropin- but not heparin-binding EGF-like growth factor-induced ERK activation and luteinization in primary granulosa cells. Together, we report that Lgr4 modulates WNT-mediated EGFR-ERK signaling to facilitate corpus luteum maturation and ovarian steroidogenesis to maintain female reproduction.
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Affiliation(s)
- Hongjie Pan
- Shanghai Key Laboratory of Regulatory Biology (H.P., H.C., S.L., Y.Q., H.W., L.L., Y.G., X.G., L.Z., M.L., D.L.), Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Contraceptive Drugs and Devices of National Population and Family Planning Commission (H.P., R.L.), Shanghai Institute of Planned Parenthood Research, Shanghai 200032, China; Life Science Institute (H.-Y.F.), Zhejiang University, Hangzhou 310058, China; Hainan Provincial Key Laboratory for Human Reproductive Medicine and Genetic Research (Y.M.), Hainan Reproductive Medical Center, the Affiliated Hospital of Hainan Medical University, Haikou 570102, China; and The Institute of Biosciences and Technology (M.L.), Texas A&M University Health Science Center, Houston, Texas 77030
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Guan X, Duan Y, Zeng Q, Pan H, Qian Y, Li D, Cao X, Liu M. Lgr4 protein deficiency induces ataxia-like phenotype in mice and impairs long term depression at cerebellar parallel fiber-Purkinje cell synapses. J Biol Chem 2014; 289:26492-26504. [PMID: 25063812 DOI: 10.1074/jbc.m114.564138] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cerebellar dysfunction causes ataxia characterized by loss of balance and coordination. Until now, the molecular and neuronal mechanisms of several types of inherited cerebellar ataxia have not been completely clarified. Here, we report that leucine-rich G protein-coupled receptor 4 (Lgr4/Gpr48) is highly expressed in Purkinje cells (PCs) in the cerebellum. Deficiency of Lgr4 leads to an ataxia-like phenotype in mice. Histologically, no obvious morphological changes were observed in the cerebellum of Lgr4 mutant mice. However, the number of PCs was slightly but significantly reduced in Lgr4(-/-) mice. In addition, in vitro electrophysiological analysis showed an impaired long term depression (LTD) at parallel fiber-PC (PF-PC) synapses in Lgr4(-/-) mice. Consistently, immunostaining experiments showed that the level of phosphorylated cAMP-responsive element-binding protein (Creb) was significantly decreased in Lgr4(-/-) PCs. Furthermore, treatment with forskolin, an adenylyl cyclase agonist, rescued phospho-Creb in PCs and reversed the impairment in PF-PC LTD in Lgr4(-/-) cerebellar slices, indicating that Lgr4 is an upstream regulator of Creb signaling, which is underlying PF-PC LTD. Together, our findings demonstrate for first time an important role for Lgr4 in motor coordination and cerebellar synaptic plasticity and provide a potential therapeutic target for certain types of inherited cerebellar ataxia.
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Affiliation(s)
- Xin Guan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China
| | - Yanhong Duan
- Key Laboratory of Brain Functional Genomics, Ministry of Education, East China Normal University, Shanghai 200241, China, and
| | - Qingwen Zeng
- Key Laboratory of Brain Functional Genomics, Ministry of Education, East China Normal University, Shanghai 200241, China, and
| | - Hongjie Pan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China
| | - Yu Qian
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China.
| | - Xiaohua Cao
- Key Laboratory of Brain Functional Genomics, Ministry of Education, East China Normal University, Shanghai 200241, China, and.
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China; Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030.
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Wang Y, Dong J, Li D, Lai L, Siwko S, Li Y, Liu M. Lgr4 regulates mammary gland development and stem cell activity through the pluripotency transcription factor Sox2. Stem Cells 2014; 31:1921-31. [PMID: 23712846 DOI: 10.1002/stem.1438] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/18/2013] [Accepted: 04/25/2013] [Indexed: 12/15/2022]
Abstract
The key signaling networks regulating mammary stem cells are poorly defined. The leucine-rich repeat containing G protein-coupled receptor (Lgr) family has been implicated in intestinal, gastric, and epidermal stem cell functions. We investigated whether Lgr4 functions in mammary gland development and mammary stem cells. We found that Lgr4(-/-) mice had delayed ductal development, fewer terminal end buds, and decreased side-branching. Crucially, the mammary stem cell repopulation capacity was severely impaired. Mammospheres from Lgr4(-/-) mice showed decreased Wnt signaling. Wnt3a treatment prevented the adverse effects of Lgr4 loss on organoid formation. Chromatin immunoprecipitation analysis indicated that Sox2 expression was controlled by the Lgr4/Wnt/β-catenin/Lef1 pathway. Importantly, Sox2 overexpression restored the in vivo mammary regeneration potential of Lgr4(-/-) mammary stem cells. Therefore, Lgr4 activates Sox2 to regulate mammary development and stem cell functions via Wnt/β-catenin/Lef1.
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Affiliation(s)
- Ying Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China; Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas, USA
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Cosín-Roger J, Ortiz-Masiá D, Calatayud S, Hernández C, Álvarez A, Hinojosa J, Esplugues JV, Barrachina MD. M2 macrophages activate WNT signaling pathway in epithelial cells: relevance in ulcerative colitis. PLoS One 2013; 8:e78128. [PMID: 24167598 PMCID: PMC3805515 DOI: 10.1371/journal.pone.0078128] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 09/09/2013] [Indexed: 12/13/2022] Open
Abstract
Macrophages, which exhibit great plasticity, are important components of the inflamed tissue and constitute an essential element of regenerative responses. Epithelial Wnt signalling is involved in mechanisms of proliferation and differentiation and expression of Wnt ligands by macrophages has been reported. We aim to determine whether the macrophage phenotype determines the expression of Wnt ligands, the influence of the macrophage phenotype in epithelial activation of Wnt signalling and the relevance of this pathway in ulcerative colitis. Human monocyte-derived macrophages and U937-derived macrophages were polarized towards M1 or M2 phenotypes and the expression of Wnt1 and Wnt3a was analyzed by qPCR. The effects of macrophages and the role of Wnt1 were analyzed on the expression of β-catenin, Tcf-4, c-Myc and markers of cell differentiation in a co-culture system with Caco-2 cells. Immunohistochemical staining of CD68, CD206, CD86, Wnt1, β-catenin and c-Myc were evaluated in the damaged and non-damaged mucosa of patients with UC. We also determined the mRNA expression of Lgr5 and c-Myc by qPCR and protein levels of β-catenin by western blot. Results show that M2, and no M1, activated the Wnt signaling pathway in co-culture epithelial cells through Wnt1 which impaired enterocyte differentiation. A significant increase in the number of CD206+ macrophages was observed in the damaged mucosa of chronic vs newly diagnosed patients. CD206 immunostaining co-localized with Wnt1 in the mucosa and these cells were associated with activation of canonical Wnt signalling pathway in epithelial cells and diminution of alkaline phosphatase activity. Our results show that M2 macrophages, and not M1, activate Wnt signalling pathways and decrease enterocyte differentiation in co-cultured epithelial cells. In the mucosa of UC patients, M2 macrophages increase with chronicity and are associated with activation of epithelial Wnt signalling and diminution in enterocyte differentiation.
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Affiliation(s)
- Jesús Cosín-Roger
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | - Dolores Ortiz-Masiá
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
- * E-mail:
| | - Sara Calatayud
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | | | - Angeles Álvarez
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | | | - Juan V. Esplugues
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
- FISABIO, Hospital Dr. Peset, Valencia, Spain
| | - Maria D. Barrachina
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
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Yi J, Xiong W, Gong X, Bellister S, Ellis LM, Liu Q. Analysis of LGR4 receptor distribution in human and mouse tissues. PLoS One 2013; 8:e78144. [PMID: 24205130 PMCID: PMC3804454 DOI: 10.1371/journal.pone.0078144] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 09/16/2013] [Indexed: 11/18/2022] Open
Abstract
LGR4 is an R-spondin receptor with strong positive effect on Wnt signaling. It plays a critical role in development as its ablation in the mouse led to total embryonic/neonatal lethality with profound defects in multiple organs. Haplotype insufficiency of LGR4 in human was associated with several diseases, including increased risk of squamous cell carcinoma of the skin, reduced birth weights, electrolyte imbalance, and decreased levels of testosterone, which are similar to the phenotypes of LGR4-hypomorphic mice. Tissue distribution of LGR4 was extensively analyzed in the mouse using gene-trap reporter enzyme alleles. However, its expression pattern in human tissues remained largely unknown. We have developed LGR4-specific monoclonal antibodies and used them to examine the expression of LGR4 in selected adult human and mouse tissues by immunohistochemical analysis. Intense LGR4-like immunoreactivity was observed in the epidermis and hair follicle of the skin, pancreatic islet cells, and epithelial cells in both the male and female reproductive organs. Of particular interest is that LGR4 is highly expressed in germ cells and pancreatic islet cells, which have important implications given the role of R-spondin-LGR4 signaling in the survival of adult stem cells. In addition, the majority of colon tumors showed elevated levels of LGR4 receptor. Overall, the expression pattern of LGR4 in human tissues mapped by this IHC analysis is similar to that in the mouse as revealed from gene trap alleles. Importantly, the pattern lends strong support to the important role of LGR4 in the development and maintenance of skin, kidney, reproductive systems, and other organs.
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Affiliation(s)
- Jing Yi
- Brown Foundation Institute of Molecular Medicine and Texas Therapeutics Institute, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Wei Xiong
- Brown Foundation Institute of Molecular Medicine and Texas Therapeutics Institute, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Xing Gong
- Brown Foundation Institute of Molecular Medicine and Texas Therapeutics Institute, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Seth Bellister
- Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Lee M. Ellis
- Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Qingyun Liu
- Brown Foundation Institute of Molecular Medicine and Texas Therapeutics Institute, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- * E-mail:
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Ostaff MJ, Stange EF, Wehkamp J. Antimicrobial peptides and gut microbiota in homeostasis and pathology. EMBO Mol Med 2013; 5:1465-83. [PMID: 24039130 PMCID: PMC3799574 DOI: 10.1002/emmm.201201773] [Citation(s) in RCA: 222] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 06/19/2013] [Accepted: 07/04/2013] [Indexed: 12/17/2022] Open
Abstract
We survive because we adapted to a world of microorganisms. All our epithelial surfaces participate in keeping up an effective barrier against microbes while not initiating ongoing inflammatory processes and risking collateral damage to the host. Major players in this scenario are antimicrobial peptides (AMPs). Such broad-spectrum innate antibiotics are in part produced by specialized cells but also widely sourced from all epithelia as well as circulating inflammatory cells. AMPs belong to an ancient defense system found in all organisms and participated in a preservative co-evolution with a complex microbiome. Particularly interesting interactions between host barrier and microbiota can be found in the gut. The intestinal cell lining not only has to maintain a tightly regulated homeostasis during its high-throughput regeneration, but also a balanced relationship towards an extreme number of mutualistic or commensal inhabitants. Recent research suggests that advancing our understanding of the circumstances of such balanced and sometimes imbalanced interactions between gut microbiota and host AMPs should have therapeutic implications for different intestinal disorders.
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Affiliation(s)
- Maureen J Ostaff
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany and University of Tuebingen, Germany
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Sone M, Oyama K, Mohri Y, Hayashi R, Clevers H, Nishimori K. LGR4 expressed in uterine epithelium is necessary for uterine gland development and contributes to decidualization in mice. FASEB J 2013; 27:4917-28. [PMID: 23975934 DOI: 10.1096/fj.13-232215] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In previous work we generated mice with a tissue specific ablation of a leucine-rich repeat containing G-protein-coupled receptor 4 (Lgr4) using the Keratin-5 (K5) Cre transgenic mouse strain (Lgr4(K5 KO)). Interestingly, the Lgr4(K5 KO) female mice were subfertile, and their embryos had impaired development. Notably, the contributions of uterine development to the subfertility phenotype were not elucidated in the previous report. In a readdress, the following study explores uterine aberration in Lgr4(K5 KO) female mice. Histological analysis revealed that the uteri of Lgr4(K5 KO) mice displayed altered epithelial differentiation characterized by a reduction in the number of uterine glands. Furthermore, Lgr4 deletion led to the reduced expression of morphoregulatory genes related to the Wnt signaling pathway. Additionally, the uteri of the Lgr4(K5 KO) mice lost the ability to undergo induced decidualization. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis and administration of recombinant leukemia inhibitory factor (LIF) demonstrated that the impaired decidualization in Lgr4(K5 KO) mice resulted from the decreased secretion of LIF concurrent with a reduction in uterine gland count. Thus, we propose that LGR4 contributes to uterine gland development, which supports decidualization during pregnancy.
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Affiliation(s)
- Mizuki Sone
- 3Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
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Hohenhaus DM, Schaale K, Le Cao KA, Seow V, Iyer A, Fairlie DP, Sweet MJ. An mRNA atlas of G protein-coupled receptor expression during primary human monocyte/macrophage differentiation and lipopolysaccharide-mediated activation identifies targetable candidate regulators of inflammation. Immunobiology 2013; 218:1345-53. [PMID: 23948647 DOI: 10.1016/j.imbio.2013.07.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 07/04/2013] [Accepted: 07/06/2013] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptors (GPCRs) are among the most important targets in drug discovery. In this study, we used TaqMan Low Density Arrays to profile the full GPCR repertoire of primary human macrophages differentiated from monocytes using either colony stimulating factor-1 (CSF-1/M-CSF) (CSF-1 Mϕ) or granulocyte macrophage colony stimulating factor (GM-CSF) (GM-CSF Mϕ). The overall trend was a downregulation of GPCRs during monocyte to macrophage differentiation, but a core set of 10 genes (e.g. LGR4, MRGPRF and GPR143) encoding seven transmembrane proteins were upregulated, irrespective of the differentiating agent used. Several of these upregulated GPCRs have not previously been studied in the context of macrophage biology and/or inflammation. As expected, CSF-1 Mϕ and GM-CSF Mϕ exhibited differential inflammatory cytokine profiles in response to the Toll-like Receptor (TLR)4 agonist lipopolysaccharide (LPS). Moreover, 15 GPCRs were differentially expressed between these cell populations in the basal state. For example, EDG1 was expressed at elevated levels in CSF-1 Mϕ versus GM-CSF Mϕ, whereas the reverse was true for EDG6. 101 GPCRs showed differential regulation over an LPS time course, with 65 of these profiles being impacted by the basal differentiation state (e.g. GPRC5A, GPRC5B). Only 14 LPS-regulated GPCRs showed asynchronous behavior (divergent LPS regulation) with respect to differentiation status. Thus, the differentiation state primarily affects the magnitude of LPS-regulated expression, rather than causing major reprogramming of GPCR gene expression profiles. Several GPCRs showing differential profiles between CSF-1 Mϕ and GM-CSF Mϕ (e.g. P2RY8, GPR92, EMR3) have not been widely investigated in macrophage biology and inflammation. Strikingly, several closely related GPCRs displayed completely opposing patterns of regulation during differentiation and/or activation (e.g. EDG1 versus EDG6, LGR4 versus LGR7, GPRC5A versus GPRC5B). We propose that selective regulation of GPCR5A and GPCR5B in CSF-1 Mϕ contributes to skewing toward the M2 macrophage phenotype. Our analysis of the GPCR repertoire expressed during primary human monocyte to macrophage differentiation and TLR4-mediated activation provides a valuable new platform for conducting future functional analyses of individual GPCRs in human macrophage inflammatory pathways.
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Affiliation(s)
- Daniel M Hohenhaus
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld 4072, Australia; Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Qld 4072, Australia
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Abstract
The leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4, also called GPR48) plays a key role in multiple developmental processes, and mice lacking Lgr4 display anterior segment dysgenesis leading to early-onset glaucomatous retinal ganglion cell loss as well as defective eyelid formation. This paper will review Lgr4 signaling and its regulation of the Axenfeld-Rieger syndrome gene Pitx2, a crucial developmental transcription factor. In addition, Wnt signaling plays an important role in eye development, with Norrin functioning to activate the Wnt receptor Frizzled 4 required for proper retinal vascularization. Recent discoveries identifying Lgr4 as a receptor for Norrin highlight the potential for Lgr4 function in retinal vascularization. Finally, several unanswered questions impeding a full understanding of Lgr4 in glaucoma are considered as avenues for further research.
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