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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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Gao Y, Zhai W, Sun L, Du X, Wang X, Mulholland MW, Yin Y, Zhang W. Hepatic LGR4 aggravates cholestasis-induced liver injury in mice. Am J Physiol Gastrointest Liver Physiol 2024; 326:G460-G472. [PMID: 38440827 PMCID: PMC11213478 DOI: 10.1152/ajpgi.00127.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 02/20/2024] [Accepted: 02/26/2024] [Indexed: 03/06/2024]
Abstract
Current therapy for hepatic injury induced by the accumulation of bile acids is limited. Leucine-rich repeat G protein-coupled receptor 4 (LGR4), also known as GPR48, is critical for cytoprotection and cell proliferation. Here, we reported a novel function for the LGR4 in cholestatic liver injury. In the bile duct ligation (BDL)-induced liver injury model, hepatic LGR4 expression was significantly downregulated. Deficiency of LGR4 in hepatocytes (Lgr4LKO) notably decreased BDL-induced liver injury measured by hepatic necrosis, fibrosis, and circulating liver enzymes and total bilirubin. Levels of total bile acids in plasma and liver were markedly reduced in these mice. However, deficiency of LGR4 in macrophages (Lyz2-Lgr4MKO) demonstrated no significant effect on liver injury induced by BDL. Deficiency of LGR4 in hepatocytes significantly attenuated S1PR2 and the phosphorylation of protein kinase B (AKT) induced by BDL. Recombinant Rspo1 and Rspo3 potentiated the taurocholic acid (TCA)-induced upregulation in S1PR2 and phosphorylation of AKT in hepatocytes. Inhibition of S1PR2-AKT signaling by specific AKT or S1PR2 inhibitors blocked the increase of bile acid secretion induced by Rspo1/3 in hepatocytes. Our studies indicate that the R-spondins (Rspos)-LGR4 signaling in hepatocytes aggravates the cholestatic liver injury by potentiating the production of bile acids in a S1PR2-AKT-dependent manner.NEW & NOTEWORTHY Deficiency of LGR4 in hepatocytes alleviates BDL-induced liver injury. LGR4 in macrophages demonstrates no effect on BDL-induced liver injury. Rspos-LGR4 increases bile acid synthesis and transport via potentiating S1PR2-AKT signaling in hepatocytes.
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Affiliation(s)
- Yuan Gao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, People's Republic of China
| | - Wenbo Zhai
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, People's Republic of China
| | - Lijun Sun
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, People's Republic of China
| | - Xueqian Du
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, People's Republic of China
| | - Xianfeng Wang
- Department of Pharmacology, School of Basic Medical Sciences, and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, People's Republic of China
| | - Michael W Mulholland
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, United States
| | - Yue Yin
- Department of Pharmacology, School of Basic Medical Sciences, and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, People's Republic of China
| | - Weizhen Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, People's Republic of China
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, United States
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Bi Y, Zhang L, Song Y, Sun L, Mulholland MW, Yin Y, Zhang W. Rspo2-LGR4 exacerbates hepatocellular carcinoma progression via activation of Wnt/β-catenin signaling pathway. GASTROENTEROLOGIA Y HEPATOLOGIA 2024; 47:352-365. [PMID: 37437654 PMCID: PMC10863972 DOI: 10.1016/j.gastrohep.2023.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 04/13/2023] [Accepted: 05/01/2023] [Indexed: 07/14/2023]
Abstract
BACKGROUND The leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4) plays an important role in stem cell differentiation, organ development and cancer. Whether LGR4 affects the progression of hepatocellular carcinoma (HCC) remains unknown. This study aimed to reveal the role of LGR4 in HCC. METHODS Clinical samples of HCC were collected to assess the expression of LGR4 and its correlation with patients' clinical characteristics. The expression level of LGR4 in HCC cells was altered by pharmacological and genetic methods, and the role of LGR4 in HCC progression was analyzed by in vivo and in vitro assays. HCC was induced by diethylnitrosamine (DEN) and carbon tetrachloride (CCl4) in wild-type and LGR4 deficient mice, the effect of LGR4 on HCC was examined by histopathological evaluation and biochemical assays. RESULTS LGR4 expression was up-regulated in HCC samples, and its expression level was positively correlated with tumor size, microvascular invasion (MVI), TNM stage and pathological differentiation grade of HCC patients. In the mouse HCC model induced by DEN+CCl4, knockdown of LGR4 effectively inhibited the progression of HCC. Silencing of LGR4 inhibited the proliferation, migration, invasion, stem cell-like properties and Warburg effect of HCC cells. These phenotypes were promoted by R-spondin2 (Rspo2), an endogenous ligand for LGR4. Rspo2 markedly increased the nuclear translocation of β-catenin, whereas IWR-1, an inhibitor of Wnt/β-catenin signaling, reversed its effect. Deficiency of LGR4 significantly reduced the nuclear translocation of β-catenin and the expression of its downstream target genes cyclinD1 and c-Myc. CONCLUSIONS LGR4 promotes HCC progression via Wnt/β-catenin signaling pathway.
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Affiliation(s)
- Yanghui Bi
- School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Liping Zhang
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Yan Song
- First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Lijun Sun
- School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Michael W Mulholland
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Yue Yin
- Department of Pharmacology, School of Basic Medical Sciences, and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, China.
| | - Weizhen Zhang
- School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China; Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, USA.
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Annunziato S, Sun T, Tchorz JS. The RSPO-LGR4/5-ZNRF3/RNF43 module in liver homeostasis, regeneration, and disease. Hepatology 2022; 76:888-899. [PMID: 35006616 DOI: 10.1002/hep.32328] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 12/02/2021] [Accepted: 01/06/2022] [Indexed: 01/05/2023]
Abstract
WNT/β-catenin signaling plays pivotal roles during liver development, homeostasis, and regeneration. Likewise, its deregulation disturbs metabolic liver zonation and is responsible for the development of a large number of hepatic tumors. Liver fibrosis, which has become a major health burden for society and a hallmark of NASH, can also be promoted by WNT/β-catenin signaling. Upstream regulatory mechanisms controlling hepatic WNT/β-catenin activity may constitute targets for the development of novel therapies addressing these life-threatening conditions. The R-spondin (RSPO)-leucine-rich repeat-containing G protein-coupled receptor (LGR) 4/5-zinc and ring finger (ZNRF) 3/ring finger 43 (RNF43) module is fine-tuning WNT/β-catenin signaling in several tissues and is essential for hepatic WNT/β-catenin activity. In this review article, we recapitulate the role of the RSPO-LGR4/5-ZNRF3/RNF43 module during liver development, homeostasis, metabolic zonation, regeneration, and disease. We further discuss the controversy around LGR5 as a liver stem cell marker.
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Affiliation(s)
- Stefano Annunziato
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Tianliang Sun
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Jan S Tchorz
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
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Yang L, Yue W, Zhang H, Gao Y, Yang L, Li L. The role of roof plate-specific spondins in liver homeostasis and disease. LIVER RESEARCH 2022. [DOI: 10.1016/j.livres.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Wu L, Tian X, Du H, Liu X, Wu H. Bioinformatics Analysis of LGR4 in Colon Adenocarcinoma as Potential Diagnostic Biomarker, Therapeutic Target and Promoting Immune Cell Infiltration. Biomolecules 2022; 12:biom12081081. [PMID: 36008975 PMCID: PMC9406187 DOI: 10.3390/biom12081081] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/31/2022] [Accepted: 08/01/2022] [Indexed: 12/24/2022] Open
Abstract
Colon adenocarcinoma is one of the tumors with the highest mortality rate, and tumorigenesis or development of colon adenocarcinoma is the major reason leading to patient death. However, the molecular mechanism and biomarker to predict tumor progression are currently unclear. With the goal of understanding the molecular mechanism and tumor progression, we utilized the TCGA database to identify differentially expressed genes. After identifying the differentially expressed genes among colon adenocarcinoma tissues with different expression levels of LGR4 and normal tissue, protein–protein interaction, gene ontology, pathway enrichment, gene set enrichment analysis, and immune cell infiltration analysis were conducted. Here, the top 10 hub genes, i.e., ALB, F2, APOA2, CYP1A1, SPRR2B, APOA1, APOB, CYP3A4, SST, and GCG, were identified, and relative correlation analysis was conducted. Kaplan–Meier analysis revealed that higher expression of LGR4 correlates with overall survival of colon adenocarcinoma patients, although expression levels of LGR4 in normal tissues are higher than in tumor tissues. Further functional analysis demonstrated that higher expression of LGR4 in colon adenocarcinoma may be linked to up-regulate metabolism-related pathways, for example, the cholesterol biosynthesis pathway. These results were confirmed by gene set enrichment analysis. Immune cell infiltration analysis clearly showed that the infiltration percentage of T cells was significantly higher than other immune cells, and TIMER analysis revealed a positive correlation between T-cell infiltration and LGR4 expression. Finally, COAD cancer cells, Caco-2, were employed to be incubated with squalene and 25-hydroxycholesterol-3-sulfate, and relative experimental results confirmed that the cholesterol biosynthesis pathway involved in modulating the proliferation of COAD tumorigenesis. Our investigation revealed that LGR4 can be an emerging diagnostic and prognostic biomarker for colon adenocarcinoma by affecting metabolism-related pathways.
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Affiliation(s)
- Lijuan Wu
- Department of Gastroenterology, the First Affiliated Hospital, College of Clinical Medicine of Henan University of Science and Technology, Luoyang 471003, China
- Correspondence: (L.W.); (H.W.)
| | - Xiaoxiao Tian
- Department of Gastroenterology, the First Affiliated Hospital, College of Clinical Medicine of Henan University of Science and Technology, Luoyang 471003, China
| | - Hao Du
- Department of Orthopedic, the First Affiliated Hospital, College of Clinical Medicine of Henan University of Science and Technology, Luoyang 471003, China
| | - Xiaomin Liu
- Department of Gastroenterology, the First Affiliated Hospital, College of Clinical Medicine of Henan University of Science and Technology, Luoyang 471003, China
| | - Haigang Wu
- School of Life Sciences, Henan University, Kaifeng 475000, China
- Correspondence: (L.W.); (H.W.)
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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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Pei J, Luan L. LGR4 protects PC12 against OGD/R-induced oxidative stress and apoptosis through activation of AKT/GSK3β. Mol Cell Toxicol 2022. [DOI: 10.1007/s13273-021-00202-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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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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Chen X, Chen L, Tan J, Zhang L, Xia J, Cheng B, Zhang W. Rspo1-LGR4 axis in BMSCs protects bone against radiation-induced injury through the mTOR-dependent autophagy pathway. J Cell Physiol 2021; 236:4273-4289. [PMID: 33452710 DOI: 10.1002/jcp.30051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/02/2020] [Accepted: 09/02/2020] [Indexed: 01/12/2023]
Abstract
While mesenchymal stem cells (MSCs) have been widely used to repair radiation-induced bone damage, the molecular mechanism underlying the effects of MSCs in the maintenance of bone homeostasis under radiation stress remains largely unknown. In this study, the role and mechanisms of R-spondin 1 (Rspo1)-leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4) axis on the initiation of self-defense of bone mesenchymal stem cells (BMSCs) and maintenance of bone homeostasis under radiation stress were investigated. Interestingly, radiation increased levels of Rspo1 and LGR4 in BMSCs. siRNA knockdown of Rspo1 or LGR4 aggravated radiation-induced impairment of self-renewal ability and osteogenic differentiation potential of BMSCs. However, exogenous Rspo1 significantly attenuated radiation-induced depletion of BMSCs, and promoted the lineage shift towards osteoblasts. This alteration was associated with the reversal of mammalian target of rapamycin (mTOR) activation and autophagy decrement. Pharmacological and genetic blockade of autophagy attenuated the radio-protective effects of Rspo1, rendering BMSCs more vulnerable to radiation-induced injury. Then bone radiation injury was induced in C57BL6J mice to further determine the radio-protective effects of Rspo1. In mice, administration of Rspo1 recombinant protein alleviated radiation-induced bone loss. Our results uncover that Rspo1-LGR4-mTOR-autophagy axis are key mechanisms by which BMSCs initiate self-defense against radiation and maintain bone homeostasis. Targeting Rspo1-LGR4 may provide a novel strategy for the intervention of radiation-induced bone damage.
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Affiliation(s)
- Xiaodan Chen
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Lingling Chen
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Jiali Tan
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Liping Zhang
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Juan Xia
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Bin Cheng
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Weizhen Zhang
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, USA
- Department of Physiology and Pathophysiology, School of Basic Science, Peking University Health Science Center, Beijing, China
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Singla B, Lin HP, Chen A, Ahn W, Ghoshal P, Cherian-Shaw M, White J, Stansfield BK, Csányi G. Role of R-spondin 2 in arterial lymphangiogenesis and atherosclerosis. Cardiovasc Res 2021; 117:1489-1509. [PMID: 32750106 PMCID: PMC8152716 DOI: 10.1093/cvr/cvaa244] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 07/16/2020] [Accepted: 07/30/2020] [Indexed: 12/17/2022] Open
Abstract
AIMS Impaired lymphatic drainage of the arterial wall results in intimal lipid accumulation and atherosclerosis. However, the mechanisms regulating lymphangiogenesis in atherosclerotic arteries are not well understood. Our studies identified elevated levels of matrix protein R-spondin 2 (RSPO2) in atherosclerotic arteries. In this study, we investigated the role of RSPO2 in lymphangiogenesis, arterial cholesterol efflux into lesion-draining lymph nodes (LNs) and development of atherosclerosis. METHODS AND RESULTS The effect of RSPO2 on lymphangiogenesis was investigated using human lymphatic endothelial cells (LEC) in vitro and implanted Matrigel plugs in vivo. Cellular and molecular approaches, pharmacological agents, and siRNA silencing of RSPO2 receptor LGR4 were used to investigate RSPO2-mediated signalling in LEC. In vivo low-density lipoprotein (LDL) tracking and perivascular blockade of RSPO2-LGR4 signalling using LGR4-extracellular domain (ECD) pluronic gel in hypercholesterolemic mice were utilized to investigate the role of RSPO2 in arterial reverse cholesterol transport and atherosclerosis. Immunoblotting and imaging experiments demonstrated increased RSPO2 expression in human and mouse atherosclerotic arteries compared to non-atherosclerotic controls. RSPO2 treatment inhibited lymphangiogenesis both in vitro and in vivo. LGR4 silencing and inhibition of RSPO2-LGR4 signalling abrogated RSPO2-induced inhibition of lymphangiogenesis. Mechanistically, we found that RSPO2 suppresses PI3K-AKT-endothelial nitric oxide synthase (eNOS) signalling via LGR4 and inhibits activation of the canonical Wnt-β-catenin pathway. ApoE-/- mice treated with LGR4-ECD developed significantly less atherosclerosis compared with control treatment. Finally, increased arterial lymphatic vessel density and improved lymphatic drainage of fluorescently labelled LDL to deep cervical LNs were observed in LGR4-ECD-treated mice. CONCLUSION These findings demonstrate that RSPO2 inhibits lymphangiogenesis via LGR4 and downstream impairment of AKT-eNOS-nitric oxide signalling. These results may also inform new therapeutic strategies to promote lymphangiogenesis and improve cholesterol efflux from atherosclerotic arteries.
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Affiliation(s)
- Bhupesh Singla
- Vascular Biology Center, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd., Augusta, GA, 30912, USA
| | - Hui-Ping Lin
- Vascular Biology Center, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd., Augusta, GA, 30912, USA
| | - Alex Chen
- Medical Scholars Program, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd., Augusta, GA, 30912, USA
| | - WonMo Ahn
- Vascular Biology Center, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd., Augusta, GA, 30912, USA
| | - Pushpankur Ghoshal
- Vascular Biology Center, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd., Augusta, GA, 30912, USA
| | - Mary Cherian-Shaw
- Vascular Biology Center, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd., Augusta, GA, 30912, USA
| | - Joseph White
- Department of Pathology, Medical College of Georgia at Augusta University, 1120 15th Street, BF 104, Augusta, GA 30912, USA
| | - Brian K Stansfield
- Vascular Biology Center, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd., Augusta, GA, 30912, USA
- Department of Pediatrics, Medical College of Georgia at Augusta University, 1120 15th Street, BI6031, Augusta, GA 30912, USA
| | - Gábor Csányi
- Vascular Biology Center, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd., Augusta, GA, 30912, USA
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd., Augusta, GA, 30912, USA
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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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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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Lu SY, Tang SM, Li FF, Kam KW, Tam POS, Yip WWK, Young AL, Tham CC, Pang CP, Yam JC, Chen LJ. Association of WNT7B and RSPO1 with Axial Length in School Children. Invest Ophthalmol Vis Sci 2021; 61:11. [PMID: 32761137 PMCID: PMC7441295 DOI: 10.1167/iovs.61.10.11] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Purpose To evaluate the association between single-nucleotide polymorphisms (SNPs) in the ZC3H11B, RSPO1, C3orf26, GJD2, ZNRF3, and WNT7B genes and myopia endophenotypes in children. Methods Seven SNPs identified in previous genome-wide association studies of axial length (AL) were genotyped in 2883 Southern Han Chinese children. Multiple linear regression analyses were conducted to evaluate the genotype association with AL, spherical equivalent (SE), corneal curvature (CC), and central corneal thickness (CCT). Results Two SNPs-namely, rs12144790 in RSPO1 (allele T, P = 0.0066, β = 0.062) and rs10453441 in WNT7B (allele A, P = 8.03 × 10-6, β = 0.103)-were significantly associated with AL. The association of rs4373767 in ZC3H11B (allele C, P = 0.030, β = -0.053) could not withstand the correction for multiple testing. WNT7B rs10453441 showed a strong association with CC (P = 1.17 × 10-14, β = 0.053) and with CCT (P = 0.0026, β = 2.65). None of the tested SNPs was significantly associated with SE. The C allele of SNP rs12321 in ZNRF3 was associated with CC (P = 0.0060, β = -0.018). Conclusions This study revealed that the RSPO1 SNP rs12144790 was associated with AL, whereas WNT7B rs10453441 was associated with AL, CC, and CCT in children. A novel association between ZNRF3 rs12321 and CC was discovered. Our data suggest that the RSPO1 and WNT7B genes might exert their effects on multiple aspects of eye growth during childhood. Potential differences in the genetic profiles of AL between children and adults should be explored in larger cohorts.
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Affiliation(s)
- Shi Yao Lu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Shu Min Tang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Fen Fen Li
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ka Wai Kam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Pancy O S Tam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wilson W K Yip
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Alvin L Young
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Clement C Tham
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China.,Hong Kong Eye Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Jason C Yam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Li Jia Chen
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
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Liu S, Gao Y, Zhang L, Yin Y, Zhang W. Rspo1/Rspo3-LGR4 signaling inhibits hepatic cholesterol synthesis through the AMPKα-SREBP2 pathway. FASEB J 2020; 34:14946-14959. [PMID: 32926477 DOI: 10.1096/fj.202001234r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/22/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022]
Abstract
R-spondins (Rspos) are endogenous ligands of leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4). Rspos-LGR4 signaling plays important roles in embryogenesis, gastrointestinal homeostasis, and food intake. Here, we investigated the impacts of Rspos-LGR4 on hepatic cholesterol synthesis. Rspo1/3 and Lgr4 knockdown mice were used to investigate the impacts of Rspo1/3-LGR4 on hepatic cholesterol synthesis. AMPKα agonist, antagonist, and shRNA were used to explore the downstream targets of Rspos-LGR4 signaling. In our study, we reported that LGR4, Rspo1, and Rspo3 were highly expressed in hepatocytes and their expressions were sensitive to energy states. Rspo1 and Rspo3 reversed OA-induced cholesterol synthesis, accompanying with increased the phosphorylation of AMPKα Thr172, reduced SREBP2 nuclear translocation, and Srebf2 mRNA expression. Conversely, hepatic LGR4 knockdown increased hepatic cholesterol synthesis and decreased the phosphorylation of AMPKα both in vitro and in vivo. Activation or inhibition of AMPKα significantly abolished the effects of LGR4 deficiency or Rspos, respectively, on cholesterol synthesis. Knockdown of AMPKα1 or/and AMPKα2 repressed Rspos-induced inhibition on cholesterol synthesis. Our study indicates that Rspo1/Rspo3-LGR4 signaling in hepatocytes suppresses cholesterol synthesis via the AMPKα-SREBP2 pathway.
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Affiliation(s)
- Shiying Liu
- School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yuan Gao
- School of Basic Medical Sciences, Peking University, Beijing, China
| | - Liping Zhang
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Yue Yin
- School of Basic Medical Sciences, Peking University, Beijing, China
| | - Weizhen Zhang
- School of Basic Medical Sciences, Peking University, Beijing, China.,Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, USA
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