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Tu J, Toh Y, Aldana AM, Wen JJ, Wu L, Jacob J, Li L, Pan S, Carmon KS, Liu QJ. Antitumor Activity of a Pyrrolobenzodiazepine Antibody-Drug Conjugate Targeting LGR5 in Preclinical Models of Neuroblastoma. Pharmaceutics 2024; 16:943. [PMID: 39065640 PMCID: PMC11279891 DOI: 10.3390/pharmaceutics16070943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Revised: 07/05/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024] Open
Abstract
Neuroblastoma (NB) is a cancer of the peripheral nervous system found in children under 15 years of age. It is the most frequently diagnosed cancer during infancy, accounting for ~12% of all cancer-related deaths in children. Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) is a membrane receptor that is associated with the primary tumor formation and metastasis of cancers in the gastrointestinal system. Remarkably, high levels of LGR5 are found in NB tumor cells, and high LGR5 expression is strongly correlated with poor survival. Antibody-drug conjugates (ADCs) are monoclonal antibodies that are covalently linked to cell-killing cytotoxins to deliver the payloads into cancer cells. We generated an ADC with an anti-LGR5 antibody and pyrrolobenzodiazepine (PBD) dimer-based payload SG3199 using a chemoenzymatic conjugation method. The resulting anti-LGR5 ADC was able to inhibit the growth of NB cells expressing LGR5 with high potency and specificity. Importantly, the ADC was able to completely inhibit the growth of NB xenograft tumors in vivo at a clinically relevant dose for the PBD class of ADCs. The findings support the potential of targeting LGR5 using the PBD class of payload for the treatment of high-risk NBs.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Qingyun J. Liu
- The Brown Foundation Institute of Molecular Medicine, Center for Translational Cancer Research, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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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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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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4
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Toh Y, Wu L, Park S, Wang A, Tu J, Yu W, Zuo M, Carmon KS, Liu QJ. LGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligands. Sci Rep 2023; 13:10796. [PMID: 37402772 DOI: 10.1038/s41598-023-37856-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/28/2023] [Indexed: 07/06/2023] Open
Abstract
LGR4 and LGR5 are two homologous receptors that potentiate Wnt/β-catenin signaling in response to R-spondin (RSPO) ligands. The RSPO and LGR4 complex binds to and inhibits activities of two related E3 ubiquitin ligases, RNF43 and ZNRF3, and thus protects Wnt receptors from the E3 ligase-mediated degradation. The RSPO and LGR5 complex, however, does not interact with the E3 ligases, and the structural basis of this difference remained unknown. Here we examined the affinities of monovalent and bivalent RSPO ligands in binding to LGR4, RNF43/ZNRF3, and LGR5 in whole cells and found unique features among the receptors and E3 ligases. Monovalent RSPO2 furin domain had much lower affinity in binding to LGR4 or RNF43/ZNRF3 than the bivalent form. In contrast, monovalent and bivalent forms had nearly identical affinity in binding to LGR5. Co-expression of ZNRF3 with LGR4 led to much higher binding affinity of the monovalent form whereas co-expression of ZNRF3 with LGR5 had no effect on the affinity. These results suggest that LGR4 and RNF43/ZNRF3 form a 2:2 dimer that accommodates bivalent binding of RSPO whereas LGR5 forms a homodimer that does not. Structural models are proposed to illustrate how RSPOs bind to LGR4, RNF43/ZNRF3, and LGR5 in whole cells.
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Affiliation(s)
- Yukimatsu Toh
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Suite 330E, Houston, TX, 77030, USA
| | - Ling Wu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Suite 330E, Houston, TX, 77030, USA
| | - Soohyun Park
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Suite 330E, Houston, TX, 77030, USA
| | - Allison Wang
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Suite 330E, Houston, TX, 77030, USA
| | - Jianghua Tu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Suite 330E, Houston, TX, 77030, USA
| | - Wangsheng Yu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Suite 330E, Houston, TX, 77030, USA
| | - Mingxin Zuo
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Suite 330E, Houston, TX, 77030, USA
| | - Kendra S Carmon
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Suite 330E, Houston, TX, 77030, USA
| | - Qingyun J Liu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Suite 330E, Houston, TX, 77030, USA.
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van Kerkhof P, Kralj T, Spanevello F, van Bloois L, Jordens I, van der Vaart J, Jamieson C, Merenda A, Mastrobattista E, Maurice MM. RSPO3 Furin domain-conjugated liposomes for selective drug delivery to LGR5-high cells. J Control Release 2023; 356:72-83. [PMID: 36813038 DOI: 10.1016/j.jconrel.2023.02.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023]
Abstract
The transmembrane receptor LGR5 potentiates Wnt/β-catenin signaling by binding both secreted R-spondin (RSPOs) and the Wnt tumor suppressors RNF43/ZNRF3, directing clearance of RNF43/ZNRF3 from the cell surface. Besides being widely used as a stem cell marker in various tissues, LGR5 is overexpressed in many types of malignancies, including colorectal cancer. Its expression characterizes a subpopulation of cancer cells that play a crucial role in tumor initiation, progression and cancer relapse, known as cancer stem cells (CSCs). For this reason, ongoing efforts are aimed at eradicating LGR5-positive CSCs. Here, we engineered liposomes decorated with different RSPO proteins to specifically detect and target LGR5-positive cells. Using fluorescence-loaded liposomes, we show that conjugation of full-length RSPO1 to the liposomal surface mediates aspecific, LGR5-independent cellular uptake, largely mediated by heparan sulfate proteoglycan binding. By contrast, liposomes decorated only with the Furin (FuFu) domains of RSPO3 are taken up by cells in a highly specific, LGR5-dependent manner. Moreover, encapsulating doxorubicin in FuFuRSPO3 liposomes allowed us to selectively inhibit the growth of LGR5-high cells. Thus, FuFuRSPO3-coated liposomes allow for the selective detection and ablation of LGR5-high cells, providing a potential drug delivery system for LGR5-targeted anti-cancer strategies.
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Affiliation(s)
- Peter van Kerkhof
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Tomica Kralj
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Francesca Spanevello
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Louis van Bloois
- Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, the Netherlands
| | - Ingrid Jordens
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Jelte van der Vaart
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Cara Jamieson
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Alessandra Merenda
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Enrico Mastrobattista
- Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, the Netherlands.
| | - Madelon M Maurice
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands.
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6
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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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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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Hidalgo-Alvarez V, Dhowre HS, Kingston OA, Sheridan CM, Levis HJ. Biofabrication of Artificial Stem Cell Niches in the Anterior Ocular Segment. Bioengineering (Basel) 2021; 8:135. [PMID: 34677208 PMCID: PMC8533470 DOI: 10.3390/bioengineering8100135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/27/2021] [Accepted: 09/27/2021] [Indexed: 11/16/2022] Open
Abstract
The anterior segment of the eye is a complex set of structures that collectively act to maintain the integrity of the globe and direct light towards the posteriorly located retina. The eye is exposed to numerous physical and environmental insults such as infection, UV radiation, physical or chemical injuries. Loss of transparency to the cornea or lens (cataract) and dysfunctional regulation of intra ocular pressure (glaucoma) are leading causes of worldwide blindness. Whilst traditional therapeutic approaches can improve vision, their effect often fails to control the multiple pathological events that lead to long-term vision loss. Regenerative medicine approaches in the eye have already had success with ocular stem cell therapy and ex vivo production of cornea and conjunctival tissue for transplant recovering patients' vision. However, advancements are required to increase the efficacy of these as well as develop other ocular cell therapies. One of the most important challenges that determines the success of regenerative approaches is the preservation of the stem cell properties during expansion culture in vitro. To achieve this, the environment must provide the physical, chemical and biological factors that ensure the maintenance of their undifferentiated state, as well as their proliferative capacity. This is likely to be accomplished by replicating the natural stem cell niche in vitro. Due to the complex nature of the cell microenvironment, the creation of such artificial niches requires the use of bioengineering techniques which can replicate the physico-chemical properties and the dynamic cell-extracellular matrix interactions that maintain the stem cell phenotype. This review discusses the progress made in the replication of stem cell niches from the anterior ocular segment by using bioengineering approaches and their therapeutic implications.
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Affiliation(s)
- Veronica Hidalgo-Alvarez
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Hala S. Dhowre
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK; (H.S.D.); (O.A.K.)
| | - Olivia A. Kingston
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK; (H.S.D.); (O.A.K.)
| | - Carl M. Sheridan
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK; (H.S.D.); (O.A.K.)
| | - Hannah J. Levis
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK; (H.S.D.); (O.A.K.)
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9
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Cui J, Toh Y, Park S, Yu W, Tu J, Wu L, Li L, Jacob J, Pan S, Carmon KS, Liu QJ. Drug Conjugates of Antagonistic R-Spondin 4 Mutant for Simultaneous Targeting of Leucine-Rich Repeat-Containing G Protein-Coupled Receptors 4/5/6 for Cancer Treatment. J Med Chem 2021; 64:12572-12581. [PMID: 34406767 DOI: 10.1021/acs.jmedchem.1c00395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
LGR4-6 (leucine-rich repeat-containing G-protein-coupled receptors 4, 5, and 6) are three related receptors with an upregulated expression in gastrointestinal cancers to various extents, and LGR5 is enriched in cancer stem cells. Antibody-drug conjugates (ADCs) targeting LGR5 showed a robust antitumor effect in vivo but could not eradicate tumors due to plasticity of LGR5-positive cancer cells. As LGR5-negative cancer cells often express LGR4 or LGR6 or both, we reasoned that simultaneous targeting of all three LGRs may provide a more effective approach. R-spondins (RSPOs) bind to LGR4-6 with high affinity and potentiate Wnt signaling. We identified an RSPO4 furin domain mutant (Q65R) that retains potent LGR binding but no longer potentiates Wnt signaling. Drug conjugates of a peptibody comprising the RSPO4 mutant and IgG1-Fc showed potent cytotoxic effects on cancer cell lines expressing any LGR in vitro and suppressed tumor growth in vivo without inducing intestinal enlargement or other adverse effects.
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Affiliation(s)
- Jie Cui
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Yukimatsu Toh
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Soohyun Park
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Wangsheng Yu
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Jianghua Tu
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Ling Wu
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Li Li
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Joan Jacob
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Sheng Pan
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Kendra S Carmon
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
| | - Qingyun J Liu
- Center for Translational Cancer Research, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Pressler St., Houston, Texas 77030, United States
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10
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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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11
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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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12
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Park S, Wu L, Tu J, Yu W, Toh Y, Carmon KS, Liu QJ. Unlike LGR4, LGR5 potentiates Wnt-β-catenin signaling without sequestering E3 ligases. Sci Signal 2020; 13:13/660/eaaz4051. [PMID: 33262293 DOI: 10.1126/scisignal.aaz4051] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
LGR4 and LGR5 encode two homologous receptors with critical, yet distinct, roles in organ development and adult stem cell survival. Both receptors are coexpressed in intestinal crypt stem cells, bind to R-spondins (RSPOs) with high affinity, and potentiate Wnt-β-catenin signaling, presumably by the same mechanism: forming RSPO-bridged complexes with the E3 ligases RNF43 and ZNRF3 to inhibit ubiquitylation of Wnt receptors. However, direct evidence for RSPO-bound, full-length LGR5 interacting with these E3 ligases in whole cells has not been reported, and only LGR4 is essential for the self-renewal of intestinal stem cells. Here, we examined the mechanisms of action of LGR4 and LGR5 in parallel using coimmunoprecipitation, proximity ligation, competition binding, and time-resolved FRET assays in whole cells. Full-length LGR4 formed a tight complex with ZNRF3 and RNF43 even without RSPO, whereas LGR5 did not interact with either E3 ligase with or without RSPO. Domain-swapping experiments with LGR4 and LGR5 revealed that the seven-transmembrane domain of LGR4 conferred interaction with the E3 ligases. Native LGR4 and LGR5 existed as dimers on the cell surface, and LGR5 interacted with both FZD and LRP6 of the Wnt signalosome to enhance LRP6 phosphorylation and potentiate Wnt-β-catenin signaling. These findings provide a molecular basis for the weaker activity of LGR5 in the potentiation of Wnt signaling that may underlie the distinct roles of LGR4 and LGR5 in organ development, as well as the self-renewal and fitness of adult stem cells.
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Affiliation(s)
- Soohyun Park
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ling Wu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Jianghua Tu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Wangsheng Yu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yukimatsu Toh
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Kendra S Carmon
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Qingyun J Liu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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13
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Zhang D, Wang Y, Lin H, Sun Y, Wang M, Jia Y, Yu X, Jiang H, Xu W, Sun JP, Xu Z. Function and therapeutic potential of G protein-coupled receptors in epididymis. Br J Pharmacol 2020; 177:5489-5508. [PMID: 32901914 DOI: 10.1111/bph.15252] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 08/08/2020] [Accepted: 09/03/2020] [Indexed: 12/14/2022] Open
Abstract
Infertility rates for both females and males have increased continuously in recent years. Currently, effective treatments for male infertility with defined mechanisms or targets are still lacking. G protein-coupled receptors (GPCRs) are the largest class of drug targets, but their functions and the implications for the therapeutic development for male infertility largely remain elusive. Nevertheless, recent studies have shown that several members of the GPCR superfamily play crucial roles in the maintenance of ion-water homeostasis of the epididymis, development of the efferent ductules, formation of the blood-epididymal barrier and maturation of sperm. Knowledge of the functions, genetic variations and working mechanisms of such GPCRs, along with the drugs and ligands relevant to their specific functions, provide future directions and a great arsenal for new developments in the treatment of male infertility.
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Affiliation(s)
- Daolai Zhang
- Department of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China.,Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China
| | - Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Hui Lin
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China
| | - Yujing Sun
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China
| | - Mingwei Wang
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China
| | - Yingli Jia
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, China
| | - Xiao Yu
- Department of Physiology, School of Medicine, Shandong University, Jinan, China
| | - Hui Jiang
- Department of Urology, Peking University Third Hospital, Beijing, China.,Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing, China
| | - Wenming Xu
- Joint Laboratory of Reproductive Medicine, SCU-CUHK, Key Laboratory of Obstetric, Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University West China Second University Hospital, Chengdu, China
| | - Jin-Peng Sun
- Department of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China.,Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China.,Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China.,Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, China
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14
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Lai S, Cheng R, Gao D, Chen YG, Deng C. LGR5 constitutively activates NF-κB signaling to regulate the growth of intestinal crypts. FASEB J 2020; 34:15605-15620. [PMID: 33001511 DOI: 10.1096/fj.202001329r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 09/01/2020] [Accepted: 09/22/2020] [Indexed: 01/09/2023]
Abstract
Mammalian LGR5 and LGR4, markers of adult stem cells, are involved in many physiological functions by enhancing WNT signaling. However, whether LGR5 and LGR4 are coupled to other intracellular signaling pathways to regulate stem cell function remains unknown. Here, we show that LGR5 and LGR4 can constitutively activate NF-κB signaling in a ligand-independent manner, which is dependent on their C-termini, but independent of receptor endocytosis. Moreover, the C-termini of LGR5/4 interact with TROY, which is required for activating NF-κB signaling. In small intestinal crypt organoids, overexpression of a C-terminal deletion mutant of LGR5 inhibits the growth and bud formation of organoids, whereas overexpression of the R-spondin-binding mutant of LGR5 that is defective for WNT signaling can still promote organoid growth. Our study reveals that NF-κB signaling, regulated by LGR5 and LGR4, plays an important role in the survival of colon cancer cells and the growth of intestinal crypts. Our findings also suggest that LGR5/4-induced NF-κB signaling and WNT signaling may co-regulate the growth of LGR5+ adult stem cells and intestinal crypts.
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Affiliation(s)
- Shanshan Lai
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ran Cheng
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Dan Gao
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ye-Guang Chen
- The State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Cheng Deng
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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15
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Pedro MP, Lund K, Iglesias-Bartolome R. The landscape of GPCR signaling in the regulation of epidermal stem cell fate and skin homeostasis. Stem Cells 2020; 38:1520-1531. [PMID: 32896043 DOI: 10.1002/stem.3273] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2020] [Indexed: 12/12/2022]
Abstract
Continuous integration of signals from the micro and macro-environment is necessary for somatic stem cells to adapt to changing conditions, maintain tissue homeostasis and activate repair mechanisms. G-protein coupled receptors (GPCRs) facilitate this integration by binding to numerous hormones, metabolites and inflammatory mediators, influencing a diverse network of pathways that regulate stem cell fate. This adaptive mechanism is particularly relevant for tissues that are exposed to environmental assault, like skin. The skin is maintained by a set of basal keratinocyte stem and progenitor cells located in the hair follicle and interfollicular epidermis, and several GPCRs and their signaling partners serve as makers and regulators of epidermal stem cell activity. GPCRs utilize heterotrimeric G protein dependent and independent pathways to translate extracellular signals into intracellular molecular cascades that dictate the activation of keratinocyte proliferative and differentiation networks, including Hedgehog GLI, Hippo YAP1 and WNT/β-catenin, ultimately regulating stem cell identity. Dysregulation of GPCR signaling underlines numerous skin inflammatory diseases and cancer, with smoothened-driven basal cell carcinoma being a main example of a GPCR associated cancer. In this review, we discuss the impact of GPCRs and their signaling partners in skin keratinocyte biology, particularly in the regulation of the epidermal stem cell compartment.
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Affiliation(s)
- M Pilar Pedro
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Katherine Lund
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Ramiro Iglesias-Bartolome
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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16
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Doherty L, Sanjay A. LGRs in Skeletal Tissues: An Emerging Role for Wnt-Associated Adult Stem Cell Markers in Bone. JBMR Plus 2020; 4:e10380. [PMID: 32666024 PMCID: PMC7340442 DOI: 10.1002/jbm4.10380] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 05/18/2020] [Accepted: 05/31/2020] [Indexed: 02/06/2023] Open
Abstract
Leucine-rich repeat-containing G protein-coupled receptors (LGRs) are adult stem cell markers that have been described across various stem cell niches, and expression of LGRs and their corresponding ligands (R-spondins) has now been reported in multiple bone-specific cell types. The skeleton harbors elusive somatic stem cell populations that are exceedingly compartment-specific and under tight regulation from various signaling pathways. Skeletal progenitors give rise to multiple tissues during development and during regenerative processes of bone, requiring postnatal endochondral and intramembranous ossification. The relevance of LGRs and the LGR/R-spondin ligand interaction in bone and tooth biology is becoming increasingly appreciated. LGRs may define specific stem cell and progenitor populations and their behavior during both development and regeneration, and their role as Wnt-associated receptors with specific ligands poses these proteins as unique therapeutic targets via potential R-spondin agonism. This review seeks to outline the current literature on LGRs in the context of bone and its associated tissues, and points to key future directions for studying the functional role of LGRs and ligands in skeletal biology. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Laura Doherty
- Department of Orthopaedic SurgeryUConn HealthFarmingtonCTUSA
| | - Archana Sanjay
- Department of Orthopaedic SurgeryUConn HealthFarmingtonCTUSA
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17
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Mancini A, Howard SR, Marelli F, Cabrera CP, Barnes MR, Sternberg MJ, Leprovots M, Hadjidemetriou I, Monti E, David A, Wehkalampi K, Oleari R, Lettieri A, Vezzoli V, Vassart G, Cariboni A, Bonomi M, Garcia MI, Guasti L, Dunkel L. LGR4 deficiency results in delayed puberty through impaired Wnt/β-catenin signaling. JCI Insight 2020; 5:133434. [PMID: 32493844 PMCID: PMC7308048 DOI: 10.1172/jci.insight.133434] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 04/23/2020] [Indexed: 12/13/2022] Open
Abstract
The initiation of puberty is driven by an upsurge in hypothalamic gonadotropin-releasing hormone (GnRH) secretion. In turn, GnRH secretion upsurge depends on the development of a complex GnRH neuroendocrine network during embryonic life. Although delayed puberty (DP) affects up to 2% of the population, is highly heritable, and is associated with adverse health outcomes, the genes underlying DP remain largely unknown. We aimed to discover regulators by whole-exome sequencing of 160 individuals of 67 multigenerational families in our large, accurately phenotyped DP cohort. LGR4 was the only gene remaining after analysis that was significantly enriched for potentially pathogenic, rare variants in 6 probands. Expression analysis identified specific Lgr4 expression at the site of GnRH neuron development. LGR4 mutant proteins showed impaired Wnt/β-catenin signaling, owing to defective protein expression, trafficking, and degradation. Mice deficient in Lgr4 had significantly delayed onset of puberty and fewer GnRH neurons compared with WT, whereas lgr4 knockdown in zebrafish embryos prevented formation and migration of GnRH neurons. Further, genetic lineage tracing showed strong Lgr4-mediated Wnt/β-catenin signaling pathway activation during GnRH neuron development. In conclusion, our results show that LGR4 deficiency impairs Wnt/β-catenin signaling with observed defects in GnRH neuron development, resulting in a DP phenotype. Defects of LGR4/Wnt-β-catenin activity compromise the development of the GnRH neuroendocrine network, resulting in delayed onset of puberty in humans and mice.
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Affiliation(s)
- Alessandra Mancini
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Sasha R Howard
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Federica Marelli
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.,IRCCS Istituto Auxologico Italiano, Department of Endocrine and Metabolic Diseases and Lab of Endocrine and Metabolic Research, Milan, Italy
| | - Claudia P Cabrera
- Centre for Translational Bioinformatics, William Harvey Research Institute, and.,NIHR Barts Cardiovascular Biomedical Research Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Michael R Barnes
- Centre for Translational Bioinformatics, William Harvey Research Institute, and.,NIHR Barts Cardiovascular Biomedical Research Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Michael Je Sternberg
- Centre for Integrative Systems Biology and Bioinformatics, Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Irene Hadjidemetriou
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Elena Monti
- St George's NHS Foundation Trust, London, United Kingdom
| | - Alessia David
- Centre for Integrative Systems Biology and Bioinformatics, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Karoliina Wehkalampi
- Children's Hospital, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Roberto Oleari
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Antonella Lettieri
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Valeria Vezzoli
- IRCCS Istituto Auxologico Italiano, Department of Endocrine and Metabolic Diseases and Lab of Endocrine and Metabolic Research, Milan, Italy
| | | | - Anna Cariboni
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Marco Bonomi
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.,IRCCS Istituto Auxologico Italiano, Department of Endocrine and Metabolic Diseases and Lab of Endocrine and Metabolic Research, Milan, Italy
| | | | - Leonardo Guasti
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Leo Dunkel
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
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18
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Zhang H, Liang F, Yue J, Liu P, Wang J, Wang Z, Li H, Cheng D, Du J, Zhang K, Du P. MicroRNA‑137 regulates hypoxia‑mediated migration and epithelial‑mesenchymal transition in prostate cancer by targeting LGR4 via the EGFR/ERK signaling pathway. Int J Oncol 2020; 57:540-549. [PMID: 32626928 DOI: 10.3892/ijo.2020.5064] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 04/15/2020] [Indexed: 11/06/2022] Open
Abstract
MicroRNAs (miRs) serve an integral role in prostate cancer. The present study aimed to investigate the effects and mechanisms of miR‑137 in hypoxia‑mediated migration and epithelial‑mesenchymal transition (EMT). PC3 and DU145 prostate cancer cells were exposed to hypoxia for 24 h, after which the expression of miR‑137 was determined by reverse transcription‑quantitative PCR (RT‑qPCR). The cells were transfected with a miR‑137 mimic or inhibitor, followed by hypoxia exposure. The results demonstrated that hypoxia reduced miR‑137 expression. Further results from the Cell Counting Kit‑8, Cell Death Detection ELISA plus kit, Transwell assay, RT‑qPCR and western blotting assays revealed that the miR‑137 mimic prevented cell proliferation, facilitated apoptosis and repressed cell migration, invasiveness, and expression of N‑cadherin, vimentin and matrix metalloproteinase 2; the miR‑137 inhibitor exerted the opposite effects. A dual‑-luciferase reporter assay determined that miR‑137 directly targeted leucine‑rich repeat‑containing G protein‑coupled receptor 4 (LGR4). Additionally, miR‑137 negatively regulated the epidermal growth factor receptor/extracellular signal‑-regulated kinase (EGFR/ERK) signaling pathway by targeting LGR4. LGR4 silencing or EGFR/ERK inhibition abolished the effects of miR‑137 inhibitor on cell migration and EMT. In conclusion, by targeting LGR4 via the EGFR/ERK signaling pathway, miR‑137 inhibited prostate cancer cell migration and EMT.
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Affiliation(s)
- Hao Zhang
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Fang Liang
- Department of Oncology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Junmin Yue
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Peng Liu
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Junyong Wang
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Zhaoyang Wang
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Hongxing Li
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Duo Cheng
- Department of Oncology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Jie Du
- Department of Oncology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Kai Zhang
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University (Zhengzhou Central Hospital), Zhengzhou, Henan 450007, P.R. China
| | - Peng Du
- Department of Urology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing ), Peking University Cancer Hospital and Institute, Beijing 100142, P.R. China
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19
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Otsuka A, Jinguji A, Maejima Y, Kasahara Y, Shimomura K, Hidema S, Nishimori K. LGR4 is essential for R-spondin1-mediated suppression of food intake via pro-opiomelanocortin. Biosci Biotechnol Biochem 2019; 83:1336-1342. [PMID: 30916623 DOI: 10.1080/09168451.2019.1591266] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Leucine-rich repeat-containing G-protein coupled receptor 4 (LGR4) suppresses food intake after its activation by binding of its ligands, R-spondins. We investigated the mechanism of food intake suppression by R-spondin1 in a region-specific Lgr4 gene knockout (LGR4 cKO) mouse model, generated by deletion of the Lgr4 gene in arcuate nucleus (ARC) using Lgr4fx/fx mice combined with infection of an AAV-Cre vector. After R-spondin1 administration, LGR4 cKO mice didn't exhibit a suppressed appetite, compared to that in control mice, which received a vehicle. In ARC of LGR4 cKO mice, Pomc mRNA expression was reduced, leading to suppressed food intake. On the other hand, neurons-specific LGR4 KO mice exhibited no differences in Pomc expression, and no structural differences were observed in the ARC of mutant mice. These results suggest that LGR4 is an essential part of the mechanism, inducing Pomc gene expression with R-spondin1 in ARC neurons in mice, thereby regulating feeding behavior. Abbreviations: LGR4: Leucine-rich repeat-containing G-protein coupled receptor 4; RSPOs: roof plate-specific spondins; ARC: arcuate nucleus; AAV: adeno associated virus; POMC: pro-opiomelanocortin; CART: cocaine and amphetamine-regulated transcript; NPY: neuropeptide Y; AgRP: agouti-related peptide; Axin2: axis inhibition protein 2; Lef1: lymphoid enhancer binding factor 1; ccnd1: cyclin D1.
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Affiliation(s)
- Ayano Otsuka
- a Department of Molecular and Cell Biology, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Ayana Jinguji
- a Department of Molecular and Cell Biology, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Yuko Maejima
- b Department of Bioregulation and Pharmacological Medicine, School of Medicine , Fukushima Medical University , Fukushima , Japan
| | - Yoshiyuki Kasahara
- c Advanced Interdisciplinary Biomedical Engineering, Graduate School of Medicine , Tohoku University , Sendai , Japan
| | - Kenju Shimomura
- b Department of Bioregulation and Pharmacological Medicine, School of Medicine , Fukushima Medical University , Fukushima , Japan
| | - Shizu Hidema
- a Department of Molecular and Cell Biology, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Katsuhiko Nishimori
- a Department of Molecular and Cell Biology, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
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20
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Khedgikar V, Lehoczky JA. Evidence for Lgr6 as a Novel Marker of Osteoblastic Progenitors in Mice. JBMR Plus 2018; 3:e10075. [PMID: 30828690 DOI: 10.1002/jbm4.10075] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/25/2018] [Accepted: 08/05/2018] [Indexed: 11/07/2022] Open
Abstract
Bone marrow-derived mesenchymal stem cells are an important source of osteoblasts critical for both bone homeostasis and repair. The ability to isolate, or specifically target, mesenchymal stem cells committed to the osteogenic lineage is necessary for orthopedic translational therapy efforts; however the precise molecular signature of these cells remains elusive. Previously, we identified a population of osteoprogenitor cells expressing the Wnt signaling agonist Lgr6, which contributes to the development and regeneration of the mouse digit tip bone. In our present study we build upon this data and investigate the expression of Lgr6 more broadly in the skeleton. We find that Lgr6, and closely related Lgr4, are expressed in mouse primary calvarial cells, bone marrow cells, and bone marrow-derived mesenchymal stem cells. In addition, our data demonstrates that Lgr4 expression is modestly increased throughout the differentiation and mineralization of mesenchymal stem cells. In contrast, we find Lgr6 expression to be strikingly increased upon osteogenic induction and subsequently decreased upon differentiation and mineralization. These findings provide evidence for Lgr6 as a novel marker of osteoprogenitor cells in bone marrow, which could prove useful for isolation of this population toward future research and clinical applications.
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Affiliation(s)
- Vikram Khedgikar
- Department of Orthopedic Surgery Brigham and Women's Hospital Harvard Medical School Boston MA USA
| | - Jessica A Lehoczky
- Department of Orthopedic Surgery Brigham and Women's Hospital Harvard Medical School Boston MA USA
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21
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Emmerson E, Knox SM. Salivary gland stem cells: A review of development, regeneration and cancer. Genesis 2018; 56:e23211. [PMID: 29663717 PMCID: PMC5980780 DOI: 10.1002/dvg.23211] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 04/11/2018] [Accepted: 04/12/2018] [Indexed: 12/13/2022]
Abstract
Salivary glands are responsible for maintaining the health of the oral cavity and are routinely damaged by therapeutic radiation for head and neck cancer as well as by autoimmune diseases such as Sjögren's syndrome. Regenerative approaches based on the reactivation of endogenous stem cells or the transplant of exogenous stem cells hold substantial promise in restoring the structure and function of these organs to improve patient quality of life. However, these approaches have been hampered by a lack of knowledge on the identity of salivary stem cell populations and their regulators. In this review we discuss our current knowledge on salivary stem cells and their regulators during organ development, homeostasis and regeneration. As increasing evidence in other systems suggests that progenitor cells may be a source of cancer, we also review whether these same salivary stem cells may also be cancer initiating cells.
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Affiliation(s)
- Elaine Emmerson
- The MRC Centre for Regenerative Medicine, The University of Edinburgh, 5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Sarah M. Knox
- Program in Craniofacial Biology, Department of Cell and Tissue Biology, University of California, 513 Parnassus Avenue, San Francisco, CA, 94143, USA
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22
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Akula M, Park JW, West-Mays JA. Relationship between neural crest cell specification and rare ocular diseases. J Neurosci Res 2018; 97:7-15. [PMID: 29660784 DOI: 10.1002/jnr.24245] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 02/15/2018] [Accepted: 03/21/2018] [Indexed: 02/06/2023]
Abstract
Development of the eye is closely associated with neural crest cell migration and specification. Eye development is extremely complex, as it requires the working of a combination of local factors, receptors, inductors, and signaling interactions between tissues such as the optic cup and periocular mesenchyme (POM). The POM is comprised of neural crest-derived mesenchymal progenitor cells that give rise to numerous important ocular structures including those tissues that form the optic cup and anterior segment of the eye. A number of genes are involved in the migration and specification of the POM such as PITX2, PITX3, FOXC1, FOXE3, PAX6, LMX1B, GPR48, TFAP2A, and TFAP2B. In this review, we will discuss the relevance of these genes in the development of the POM and how mutations and defects result in rare ocular diseases.
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Affiliation(s)
- Monica Akula
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Jeong Won Park
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Judith A West-Mays
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
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23
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Kang YE, Kim JM, Kim KS, Chang JY, Jung M, Lee J, Yi S, Kim HW, Kim JT, Lee K, Choi MJ, Kang SK, Lee SE, Yi HS, Koo BS, Shong M. Upregulation of RSPO2-GPR48/LGR4 signaling in papillary thyroid carcinoma contributes to tumor progression. Oncotarget 2017; 8:114980-114994. [PMID: 29383135 PMCID: PMC5777747 DOI: 10.18632/oncotarget.22692] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 10/04/2017] [Indexed: 01/07/2023] Open
Abstract
The signaling pathway involving the R-spondins and its cognate receptor, GPR48/LGR4, is crucial in development and carcinogenesis. However, the functional implications of the R-spondin-GPR48/LGR4 pathway in thyroid remain to be identified. The aim of this study was to investigate the role of R-spondin-GPR48/LGR4 signaling in papillary thyroid carcinomas. We retrospectively reviewed a total of 214 patients who underwent total thyroidectomy and cervical lymph node dissection for papillary thyroid carcinoma. The role of GPR48/LGR4 in proliferation and migration was examined in thyroid cancer cell lines. R-spondin 2, and GPR48/LGR4 were expressed at significantly higher levels in thyroid cancer than in normal controls. Elevated GPR48/LGR4 expression was significantly associated with tumor size (P=0.049), lymph node metastasis (P=0.004), recurrence (P=0.037), and the BRAFV600E mutation (P=0.003). Moreover, high GPR48/LGR4 expression was an independent risk factor for lymph node metastasis (P=0.027) and the BRAFV600E mutation (P=0.009). in vitro assays demonstrated that elevated expression of GPR48/LGR4 promoted proliferation and migration of thyroid cancer cells, whereas downregulation of GPR48/LGR4 decreased proliferation and migration by inhibition of the β-catenin pathway. Moreover, treatment of thyroid cancer cells with exogenous R-spondin 2 induced activation of the β-catenin pathway through GPR48/LGR4. The R-spondin 2-GPR48/LGR4 signaling axis also induced the phosphorylation of ERK, as well as phosphorylation of LRP6 and serine 9 of GSK3β. Our findings demonstrate that upregulation of the R-spondin 2-GPR48/LGR4 pathway contributes to tumor aggressiveness in papillary thyroid carcinoma by promoting ERK phosphorylation, suggesting that this pathway represents a novel therapeutic target for treatment of differentiated thyroid cancer.
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Affiliation(s)
- Yea Eun Kang
- Department of Endocrinology and Metabolism, College of Medicine, Chungnam National University, Daejeon 35015, South Korea
| | - Jin-Man Kim
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea.,Department of Pathology, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Koon Soon Kim
- Department of Endocrinology and Metabolism, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Joon Young Chang
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Mingyu Jung
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Junguee Lee
- Department of Pathology, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Daejeon 34943, Republic of Korea
| | - Shinae Yi
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Hyeon Woo Kim
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Jung Tae Kim
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Kyungmin Lee
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Min Jeong Choi
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Seul Ki Kang
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Seong Eun Lee
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Hyon-Seung Yi
- Department of Endocrinology and Metabolism, College of Medicine, Chungnam National University, Daejeon 35015, South Korea
| | - Bon Seok Koo
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea.,Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Minho Shong
- Department of Endocrinology and Metabolism, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
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24
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Xu Y, Zhou T, Shao L, Zhang B, Liu K, Gao C, Gao L, Liu J, Cui Y, Chian RC. Gene expression profiles in mouse cumulus cells derived from in vitro matured oocytes with and without blastocyst formation. Gene Expr Patterns 2017; 25-26:46-58. [DOI: 10.1016/j.gep.2017.05.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/26/2017] [Accepted: 05/30/2017] [Indexed: 12/11/2022]
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25
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An X, Liu X, Zhang L, Liu J, Zhao X, Chen K, Ma H, Li G, Cao B, Song Y. MiR-449a regulates caprine endometrial stromal cell apoptosis and endometrial receptivity. Sci Rep 2017; 7:12248. [PMID: 28947781 PMCID: PMC5612931 DOI: 10.1038/s41598-017-12451-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 09/08/2017] [Indexed: 11/09/2022] Open
Abstract
In this study, an RT-qPCR analysis showed that the expression levels of miR-449a in the pre-receptive endometrium were lower compared to the receptive endometrium, which is consistent with previous sequencing data (previous investigations). To detect the role of miR-449a in endometrial receptivity, we transfected caprine endometrial stromal cells (ESCs) cultured in vitro with miR-449a mimics. The results revealed that miR-449a decreased the mRNA and protein levels of LGR4 by targeting its 3′-untranslated region. The miR-449a mimics significantly reduced the G1 cell population from 52.56% (mimic NC) to 42.19% with a concordant increase in the G2 and S cell populations from 47.44% (mimic NC) to 57.81%, suggesting that miR-449a caused ESC cell cycle arrest. In addition, the number of apoptotic cells was significantly higher in ESCs transfected with miR-449a mimics (P < 0.05) than in ESCs transfected with mimic NC. In vivo, rich pinopodes were observed on the endometrial surface in the miR-449a agomir group compared with the miR-449a antagomir group. The results of hematoxylin-eosin staining showed that endometrial thickness was significantly increased in the miR-449a agomir group compared with the miR-449a antagomir group. These results suggest that miR-449a could enhance endometrial receptivity.
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Affiliation(s)
- Xiaopeng An
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Xiaorui Liu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Lei Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Junze Liu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Xinyan Zhao
- Northwest A&F University of Hospital, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Kaiwen Chen
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Haidong Ma
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Guang Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Binyun Cao
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China.
| | - Yuxuan Song
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China.
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26
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Cox B, Roose H, Vennekens A, Vankelecom H. Pituitary stem cell regulation: who is pulling the strings? J Endocrinol 2017; 234:R135-R158. [PMID: 28615294 DOI: 10.1530/joe-17-0083] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 06/14/2017] [Indexed: 12/28/2022]
Abstract
The pituitary gland plays a pivotal role in the endocrine system, steering fundamental processes of growth, metabolism, reproduction and coping with stress. The adult pituitary contains resident stem cells, which are highly quiescent in homeostatic conditions. However, the cells show marked signs of activation during processes of increased cell remodeling in the gland, including maturation at neonatal age, adaptation to physiological demands, regeneration upon injury and growth of local tumors. Although functions of pituitary stem cells are slowly but gradually uncovered, their regulation largely remains virgin territory. Since postnatal stem cells in general reiterate embryonic developmental pathways, attention is first being given to regulatory networks involved in pituitary embryogenesis. Here, we give an overview of the current knowledge on the NOTCH, WNT, epithelial-mesenchymal transition, SHH and Hippo pathways in the pituitary stem/progenitor cell compartment during various (activation) conditions from embryonic over neonatal to adult age. Most information comes from expression analyses of molecular components belonging to these networks, whereas functional extrapolation is still very limited. From this overview, it emerges that the 'big five' embryonic pathways are indeed reiterated in the stem cells of the 'lazy' homeostatic postnatal pituitary, further magnified en route to activation in more energetic, physiological and pathological remodeling conditions. Increasing the knowledge on the molecular players that pull the regulatory strings of the pituitary stem cells will not only provide further fundamental insight in postnatal pituitary homeostasis and activation, but also clues toward the development of regenerative ideas for improving treatment of pituitary deficiency and tumors.
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Affiliation(s)
- Benoit Cox
- Department of Development and RegenerationCluster of Stem Cell and Developmental Biology, Unit of Stem Cell Research, University of Leuven (KU Leuven), Leuven, Belgium
| | - Heleen Roose
- Department of Development and RegenerationCluster of Stem Cell and Developmental Biology, Unit of Stem Cell Research, University of Leuven (KU Leuven), Leuven, Belgium
| | - Annelies Vennekens
- Department of Development and RegenerationCluster of Stem Cell and Developmental Biology, Unit of Stem Cell Research, University of Leuven (KU Leuven), Leuven, Belgium
| | - Hugo Vankelecom
- Department of Development and RegenerationCluster of Stem Cell and Developmental Biology, Unit of Stem Cell Research, University of Leuven (KU Leuven), Leuven, Belgium
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27
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Dailey WA, Drenser KA, Wong SC, Cheng M, Vercellone J, Roumayah KK, Feeney EV, Deshpande M, Guzman AE, Trese M, Mitton KP. Norrin treatment improves ganglion cell survival in an oxygen-induced retinopathy model of retinal ischemia. Exp Eye Res 2017; 164:129-138. [PMID: 28823941 DOI: 10.1016/j.exer.2017.08.012] [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: 03/09/2017] [Revised: 07/17/2017] [Accepted: 08/14/2017] [Indexed: 12/25/2022]
Abstract
Treatment of a mouse model of oxygen-induced retinopathy (OIR) with recombinant human Norrin (Norrie Disease Protein, gene: NDP) accelerates regrowth of the microvasculature into central ischemic regions of the neural retina, which are generated after treatment with 75% oxygen. While this reduces the average duration and severity of ischemia overall, we do not know if this accelerated recovery of the microvasculature results in any significant survival of retinal ganglion cells (RGCs). The purpose of this study was to investigate ganglion cell survival with and without the intravitreal injection of Norrin in the murine model of oxygen induced retinopathy (OIR), using two strains of mice: C57BL/6J and Thy1-YFP mice. Intravitreal injections of Norrin or vehicle were done after five days of exposure to 75% oxygen from ages P7 to P12. The C57BL/J mice were followed by Spectral-Domain Optical Coherence Tomography (SD-OCT), and the average nerve fiber layer (NFL) and inner-plexiform layer (IPL) thicknesses were measured at twenty-four locations per retina at P42. Additionally, some C57BL/J retinas were flat mounted and immunostained for the RGC marker, Brn3a, to compare the population density of surviving retinal ganglion cells. Using homozygous Thy1-YFP mice, single intrinsically fluorescent RGCs were imaged in live animals with a Micron-III imaging system at ages P21, 28 and P42. The relative percentage of YFP-fluorescent RGCs with dendritic arbors were compared. At age P42, the NFL was thicker in Norrin-injected OIR eyes, 14.4 μm, compared to Vehicle-injected OIR eyes, 13.3 μm (p = 0.01). In the superior retina, the average thickness of the IPL was greater in Norrin-injected OIR eyes, 37.7 μm, compared to Vehicle-injected OIR eyes, 34.6 μm (p = 0.04). Retinas from Norrin injected OIR mice had significantly more surviving RGCs (p = 0.03) than vehicle-injected mice. Based upon NFL thickness and counts of RGCs, we conclude that Norrin treatment, early in the ischemic phase, increased the relative population density of surviving RGCs in the central retinas of OIR mice.
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Affiliation(s)
- Wendy A Dailey
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Kimberly A Drenser
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States; Associated Retinal Consultants, Novi, MI, United States
| | - Sui Chien Wong
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Mei Cheng
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Joseph Vercellone
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Kevin K Roumayah
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Erin V Feeney
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Mrinalini Deshpande
- Control of Gene Expression Laboratory, Eye Research Institute, Oakland University, United States
| | - Alvaro E Guzman
- Control of Gene Expression Laboratory, Eye Research Institute, Oakland University, United States
| | - Michael Trese
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States; Associated Retinal Consultants, Novi, MI, United States
| | - Kenneth P Mitton
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States; Control of Gene Expression Laboratory, Eye Research Institute, Oakland University, United States.
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28
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Schindler AJ, Watanabe A, Howell SB. LGR5 and LGR6 in stem cell biology and ovarian cancer. Oncotarget 2017; 9:1346-1355. [PMID: 29416699 PMCID: PMC5787443 DOI: 10.18632/oncotarget.20178] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/31/2017] [Indexed: 12/19/2022] Open
Abstract
Wnt signaling plays a fundamental role in patterning of the embryo and maintenance of stem cells in numerous epithelia. Epithelial stem cells are closeted in niches created by surrounding differentiated cells that express secreted Wnt and R-spondin proteins that influence proliferation rate and fate determination of stem cell daughters. R-spondins act through the LGR receptors to enhance Wnt signaling. This close association of stem cells with more differentiated regulatory cells expressing Wnt-pathway ligands is a feature replicated in all of the epithelial stem cell systems thus far examined. How the stem cell niche operates through these short-range interactions is best understood for the crypts of the gastrointestinal epithelium and skin. Less well understood are the stem cells that function in the ovarian surface epithelium (OSE) and fallopian tube epithelium (FTE). While the cuboidal OSE appears to be made up of a single cell type, the cells of the FTE progress through a life cycle that involves differentiation into ciliated and secretory subtypes that are eventually shed into the lumen in a manner similar to the gastrointestinal epithelium. Available evidence suggests that high grade serous ovarian carcinoma (HGSOC) originates most often from stem cells in the FTE and that Wnt signaling augmented by LGR6 supports tumor development and progression. This review summarizes current information on LGR5 and LGR6 in the OSE and FTE and how their niches are organized relative to that of the gastrointestinal epithelium and skin.
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Affiliation(s)
- Adam J Schindler
- Moores Cancer Center, University of California, San Diego, CA, USA
| | - Arisa Watanabe
- Moores Cancer Center, University of California, San Diego, CA, USA
| | - Stephen B Howell
- Moores Cancer Center, University of California, San Diego, CA, USA
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29
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Rajkumar P, Pluznick JL. Unsung renal receptors: orphan G-protein-coupled receptors play essential roles in renal development and homeostasis. Acta Physiol (Oxf) 2017; 220:189-200. [PMID: 27699982 DOI: 10.1111/apha.12813] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/23/2016] [Accepted: 09/29/2016] [Indexed: 12/31/2022]
Abstract
Recent studies have shown that orphan GPCRs of the GPR family are utilized as specialized chemosensors in various tissues to detect metabolites, and in turn to activate downstream pathways which regulate systemic homeostasis. These studies often find that such metabolites are generated by well-known metabolic pathways, implying that known metabolites and chemicals may perform novel functions. In this review, we summarize recent findings highlighting the role of deorphanized GPRs in renal development and function. Understanding the role of these receptors is critical in gaining insights into mechanisms that regulate renal function both in health and in disease.
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Affiliation(s)
- P. Rajkumar
- Department of Physiology; Johns Hopkins School of Medicine; Baltimore; MD USA
| | - J. L. Pluznick
- Department of Physiology; Johns Hopkins School of Medicine; Baltimore; MD USA
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30
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LGR4 Is a Direct Target of MicroRNA-34a and Modulates the Proliferation and Migration of Retinal Pigment Epithelial ARPE-19 Cells. PLoS One 2016; 11:e0168320. [PMID: 27977785 PMCID: PMC5158047 DOI: 10.1371/journal.pone.0168320] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 11/30/2016] [Indexed: 01/02/2023] Open
Abstract
The pathology of proliferative vitreoretinopathy and proliferative diabetic retinopathy is linked to proliferation, migration, and adhesion of the retinal pigment epithelium. MicroRNA-34a (miR-34a) expression modulates changes in proliferation and migration of retinal pigment epithelial cell line ARPE-19. In this study, we determined that miR-34a interacts with LGR4, identified by bioinformatics using TargetScan Human 5.0, to affect these changes. Double luciferase gene reporter assay confirmed miR-34a involvement in mediating control. miR-34a mimic transfection decreased LGR4 expression. Western blot analysis documented corresponding protein expression inhibition. MTS, Ki67 immunostaining, scratch and transwell testing, along with attachment assay showed that miR-34a upregulation inhibited ARPE-19 cell proliferation, migration and attachment partly through downregulation of LGR4 protein expression. Western blot analysis revealed that both miR-34a upregulation and LGR4 downregulation induced declines in E2F1, p-CDC2, CDK2, CDK4 and CDK6 protein expression. Taken together, miR-34a gene expression upregulation inhibits ARPE-19 cell proliferation, migration and adhesion partly by suppressing LGR4 expression. These results substantiate earlier indications that both miR-34a and LGR4 are potential drug targets to prevent fibrosis in a clinical setting.
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31
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LGR4 is required for sequential molar development. Biochem Biophys Rep 2016; 8:174-183. [PMID: 28955954 PMCID: PMC5613770 DOI: 10.1016/j.bbrep.2016.08.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/30/2016] [Accepted: 08/14/2016] [Indexed: 12/20/2022] Open
Abstract
Tooth development requires proliferation, differentiation, and specific migration of dental epithelial cells, through well-organized signaling interactions with mesenchymal cells. Recently, it has been reported that leucine-rich repeat-containing G protein coupled receptor 4 (LGR4), the receptor of R-spondins, is expressed in many epithelial cells in various organs and tissues and is essential for organ development and stem cell maintenance. Here, we report that LGR4 contributes to the sequential development of molars in mice. LGR4 expression in dental epithelium was detected in SOX2+ cells in the posterior end of the second molar (M2) and the early tooth germ of the third molar (M3). In keratinocyte-specific Lgr4-deficient mice (Lgr4K5 KO), the developmental defect became obvious by postnatal day 14 (P14) in M3. Lgr4K5 KO adult mice showed complete absence or the dwarfed form of M3. In M3 development in Lgr4K5 KO mice, at Wnt/β-catenin signal activity was down-regulated in the dental epithelium at P3, as indicated by lymphoid enhancer-binding factor-1 (LEF1) expression. We also confirmed the decrease, in dental epithelium of Lgr4K5 KO mice, of the number of SOX2+ cells and the arrest of cell proliferation at P7, and observed abnormal differentiation at P14. Our data demonstrated that LGR4 controls the sequential development of molars by maintaining SOX2+ cells in the dental epithelium, which have the ability to form normal molars. LGR4 expression was observed in the dental epithelium after birth and moved posteriorly during molar development. Keratin5-Cre Tg specific deletion of Lgr4 impaired the development of the third molar. LGR4 maintained SOX2 positive and proliferative cells in the dental epithelium of molars.
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den Hartogh SC, Wolstencroft K, Mummery CL, Passier R. A comprehensive gene expression analysis at sequential stages of in vitro cardiac differentiation from isolated MESP1-expressing-mesoderm progenitors. Sci Rep 2016; 6:19386. [PMID: 26783251 PMCID: PMC4726039 DOI: 10.1038/srep19386] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/02/2015] [Indexed: 01/03/2023] Open
Abstract
In vitro cardiac differentiation of human pluripotent stem cells (hPSCs) closely recapitulates in vivo embryonic heart development, and therefore, provides an excellent model to study human cardiac development. We recently generated the dual cardiac fluorescent reporter MESP1mCherry/wNKX2-5eGFP/w line in human embryonic stem cells (hESCs), allowing the visualization of pre-cardiac MESP1+ mesoderm and their further commitment towards the cardiac lineage, marked by activation of the cardiac transcription factor NKX2-5. Here, we performed a comprehensive whole genome based transcriptome analysis of MESP1-mCherry derived cardiac-committed cells. In addition to previously described cardiac-inducing signalling pathways, we identified novel transcriptional and signalling networks indicated by transient activation and interactive network analysis. Furthermore, we found a highly dynamic regulation of extracellular matrix components, suggesting the importance to create a versatile niche, adjusting to various stages of cardiac differentiation. Finally, we identified cell surface markers for cardiac progenitors, such as the Leucine-rich repeat-containing G-protein coupled receptor 4 (LGR4), belonging to the same subfamily of LGR5, and LGR6, established tissue/cancer stem cells markers. We provide a comprehensive gene expression analysis of cardiac derivatives from pre-cardiac MESP1-progenitors that will contribute to a better understanding of the key regulators, pathways and markers involved in human cardiac differentiation and development.
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Affiliation(s)
- Sabine C den Hartogh
- Department of Anatomy and Embryology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Katherine Wolstencroft
- Leiden Institute of Advanced Computer Science Leiden Institute of Advanced Computer Science, Leiden University, The Netherlands
| | - Christine L Mummery
- Department of Anatomy and Embryology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Robert Passier
- Department of Anatomy and Embryology, Leiden University Medical Centre, Leiden, The Netherlands.,Department of Applied Stem cell Technologies. MIRA Institute for Biomedical Technology and Technical Medicine. University of Twente, P.O.Box 217, Enschede, The Netherlands
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Lgr6 marks nail stem cells and is required for digit tip regeneration. Proc Natl Acad Sci U S A 2015; 112:13249-54. [PMID: 26460010 DOI: 10.1073/pnas.1518874112] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The tips of the digits of some mammals, including human infants and mice, are capable of complete regeneration after injury. This process is reliant on the presence of the overlaying nail organ and is mediated by a proliferative blastema. Epithelial Wnt/β-catenin signaling has been shown to be necessary for mouse digit tip regeneration. Here, we report on Lgr5 and Lgr6 (leucine-rich repeat-containing G protein-coupled receptor 5 and 6), two important agonists of the Wnt pathway that are known to be markers of several epithelial stem cell populations. We find that Lgr5 is expressed in a dermal population of cells adjacent to the specialized epithelia surrounding the keratinized nail plate. Moreover, Lgr5-expressing cells contribute to this dermis, but not the blastema, during digit tip regeneration. In contrast, we find that Lgr6 is expressed within cells of the nail matrix portion of the nail epithelium, as well as in a subset of cells in the bone and eccrine sweat glands. Genetic lineage analysis reveals that Lgr6-expressing cells give rise to the nail during homeostatic growth, demonstrating that Lgr6 is a marker of nail stem cells. Moreover, Lgr6-expressing cells contribute to the blastema, suggesting a potential direct role for Lgr6-expressing cells during digit tip regeneration. This role is confirmed by analysis of Lgr6-deficient mice, which have both a nail and bone regeneration defect.
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Abstract
PURPOSE OF REVIEW This review will summarize recent literature highlighting the roles of sensory Gpr receptors and their roles in renal function. RECENT FINDINGS Chemoreceptors play important roles in renal physiology wherein they modulate renal function in response to ligands from a variety of sources. SUMMARY As specialized chemical detectors, chemoreceptors in the kidney monitor the level of a variety of chemical ligands in the body and adjust renal function accordingly. In addition to olfactory receptors and taste receptors, G-protein coupled receptors of the orphan Gpr family are now being found to play a 'sensory' role in renal physiology. Identifying the physiological roles of these receptors and elucidating the cell biology underlying these signaling pathways can give us novel insights into renal function.
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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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A naturally occurring Lgr4 splice variant encodes a soluble antagonist useful for demonstrating the gonadal roles of Lgr4 in mammals. PLoS One 2014; 9:e106804. [PMID: 25188337 PMCID: PMC4154783 DOI: 10.1371/journal.pone.0106804] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 08/05/2014] [Indexed: 01/10/2023] Open
Abstract
Leucine-rich repeat containing G protein-coupled receptor 4 (LGR4) promotes the Wnt signaling through interaction with R-spondins or norrin. Using PCR amplification from rat ovarian cDNAs, we identified a naturally occurring Lgr4 splice variant encoding only the ectodomain of Lgr4, which was named Lgr4-ED. Lgr4-ED can be detected as a secreted protein in the extracts from rodent and bovine postnatal gonads, suggesting conservation of Lgr4-ED in mammals. Recombinant Lgr4-ED purified from the conditioned media of transfected 293T cells was found to dose-dependently inhibit the LGR4-mediated Wnt signaling induced by RSPO2 or norrin, suggesting that it is capable of ligand absorption and could have a potential role as an antagonist. Intraperitoneal injection of purified recombinant Lgr4-ED into newborn mice was found to significantly decrease the testicular expression of estrogen receptor alpha and aquaporin 1, which is similar to the phenotype found in Lgr4-null mice. Administration of recombinant Lgr4-ED to superovulated female rats can also decrease the expression of estrogen receptor alpha, aquaporin 1, LH receptor and other key steroidogenic genes as well as bring about the suppression of progesterone production. Thus, these findings suggest that endogenously expressed Lgr4-ED may act as an antagonist molecule and help to fine-tune the R-spondin/norrin-mediated Lgr4-Wnt signaling during gonadal development.
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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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38
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Abstract
Adult stem cells are controlled by an intricate interplay of potent Wnt agonists, antagonists, and anti-antagonists. This review by de Lau et al. focuses on the complex physical and functional interactions of three recently discovered protein families that control stem cell activity by regulating surface expression of Wnt receptors: Lgr5 and its homologs, the E3 ligases Rnf43 and Znrf3, and the secreted R-spondin ligands. Lgr5 was originally discovered as a common Wnt target gene in adult intestinal crypts and colon cancer. It was subsequently identified as an exquisite marker of multiple Wnt-driven adult stem cell types. Lgr5 and its homologs, Lgr4 and Lgr6, constitute the receptors for R-spondins, potent Wnt signal enhancers and stem cell growth factors. The Lgr5/R-spondin complex acts by neutralizing Rnf43 and Znrf3, two transmembrane E3 ligases that remove Wnt receptors from the stem cell surface. Rnf43/Znrf3 are themselves encoded by Wnt target genes and constitute a negative Wnt feedback loop. Thus, adult stem cells are controlled by an intricate interplay of potent Wnt agonists, antagonists, and anti-antagonists.
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Affiliation(s)
- Wim de Lau
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Centre Utrecht, 3584 CT Utrecht, The Netherlands
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Yi T, Weng J, Siwko S, Luo J, Li D, Liu M. LGR4/GPR48 inactivation leads to aniridia-genitourinary anomalies-mental retardation syndrome defects. J Biol Chem 2014; 289:8767-80. [PMID: 24519938 DOI: 10.1074/jbc.m113.530816] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
AGR syndrome (the clinical triad of aniridia, genitourinary anomalies, and mental retardation, a subgroup of WAGR syndrome for Wilm's tumor, aniridia, genitourinary anomalies, and mental retardation) is a rare syndrome caused by a contiguous gene deletion in the 11p13-14 region. However, the mechanisms of WAGR syndrome pathogenesis are elusive. In this study we provide evidence that LGR4 (also named GPR48), the only G-protein-coupled receptor gene in the human chromosome 11p12-11p14.4 fragment, is the key gene responsible for the diseases of AGR syndrome. Deletion of Lgr4 in mouse led to aniridia, polycystic kidney disease, genitourinary anomalies, and mental retardation, similar to the pathological defects of AGR syndrome. Furthermore, Lgr4 inactivation significantly increased cell apoptosis and decreased the expression of multiple important genes involved in the development of WAGR syndrome related organs. Specifically, deletion of Lgr4 down-regulated the expression of histone demethylases Jmjd2a and Fbxl10 through cAMP-CREB signaling pathways both in mouse embryonic fibroblast cells and in urinary and reproductive system mouse tissues. Our data suggest that Lgr4, which regulates eye, kidney, testis, ovary, and uterine organ development as well as mental development through genetic and epigenetic surveillance, is a novel candidate gene for the pathogenesis of AGR syndrome.
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Affiliation(s)
- Tingfang Yi
- From the Institute of Biosciences and Technology and Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Houston, Texas 77030 and
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40
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Li JY, Chai B, Zhang W, Fritze DM, Zhang C, Mulholland MW. LGR4 and its ligands, R-spondin 1 and R-spondin 3, regulate food intake in the hypothalamus of male rats. Endocrinology 2014; 155:429-40. [PMID: 24280058 PMCID: PMC3891940 DOI: 10.1210/en.2013-1550] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The hypothalamus plays a key role in the regulation of feeding behavior. Several hypothalamic nuclei, including the arcuate nucleus (ARC), paraventricular nucleus, and ventromedial nucleus of the hypothalamus (VMH), are involved in energy homeostasis. Analysis of microarray data derived from ARC revealed that leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4) is highly expressed. LGR4, LGR5, and LGR6 form a subfamily of closely related receptors. Recently, R-spondin (Rspo) family proteins were identified as ligands of the LGR4 subfamily. In the present study, we investigated the distribution and function of LGR4-LGR6 and Rspos (1-4) in the brain of male rat. In situ hybridization showed that LGR4 is expressed in the ARC, VMH, and median eminence of the hypothalamus. LGR4 colocalizes with neuropeptide Y, proopiomelanocortin, and brain-derived neurotrophic factor neurons. LGR5 is not detectable with in situ hybridization; LGR6 is only expressed in the epithelial lining of the lower portion of the third ventricle and median eminence. Rspo1 is expressed in the VMH and down-regulated with fasting. Rspo3 is expressed in the paraventricular nucleus and also down-regulated with fasting. Rspos 1 and 3 colocalize with the neuronal marker HuD, indicating that they are expressed by neurons. Injection of Rspo1 or Rspo3 into the third brain ventricle inhibited food intake. Rspo1 decreased neuropeptide Y and increased proopiomelanocortin expression in the ARC. Rspo1 and Rspo3 mRNA is up-regulated by insulin. These data indicate that Rspo1 and Rspo3 and their receptor LGR4 form novel circuits in the brain to regulate energy homeostasis.
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Affiliation(s)
- Ji-Yao Li
- Department of Surgery, University of Michigan, Ann Arbor, Michigan 48109-0346
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41
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Sun X, Terakawa J, Clevers H, Barker N, Daikoku T, Dey SK. Ovarian LGR5 is critical for successful pregnancy. FASEB J 2014; 28:2380-9. [PMID: 24469993 DOI: 10.1096/fj.13-248344] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5) is expressed in many organs, including female reproductive organs, and is a stem cell marker in the stomach and intestinal epithelium, hair follicles, and ovarian surface epithelium. Despite ongoing studies, the definitive physiological functions of Lgr5 remain unclear. We utilized mice with conditional deletion of Lgr5 (Lgr5(d/d)) in the female reproductive organs by progesterone receptor-Cre (Pgr(Cre)) to determine Lgr5's functions during pregnancy. Only 30% of plugged Lgr5(d/d) females delivered live pups, and their litter sizes were lower. We found that pregnancy failure in Lgr5(d/d) females was due to insufficient ovarian progesterone (P4) secretion that compromised decidualization, terminating pregnancy. The drop in P4 levels was reflected in elevated levels of P4-metabolizing enzyme 20α-hydroxysteroid dehydrogenase in corpora lutea (CL) inactivated of Lgr5. Of interest, P4 supplementation rescued decidualization failure and supported pregnancy to full term in Lgr5(d/d) females. These results provide strong evidence that Lgr5 is critical to normal CL function, unveiling a new role of LGR5 in the ovary.
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Affiliation(s)
- Xiaofei Sun
- 1Cincinnati Children's Hospital Medical Center, Division of Reproductive Sciences, MLC 7045, 3333 Burnet Ave., Cincinnati, OH 45229, USA.
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42
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Biggs LC, Mikkola ML. Early inductive events in ectodermal appendage morphogenesis. Semin Cell Dev Biol 2014; 25-26:11-21. [DOI: 10.1016/j.semcdb.2014.01.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 01/23/2014] [Accepted: 01/24/2014] [Indexed: 01/18/2023]
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43
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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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44
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Kwon MS, Park BO, Kim HM, Kim S. Leucine-rich repeat-containing G-protein coupled receptor 5/GPR49 activates G12/13-Rho GTPase pathway. Mol Cells 2013; 36:267-72. [PMID: 23912594 PMCID: PMC3887977 DOI: 10.1007/s10059-013-0173-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 06/27/2013] [Accepted: 06/27/2013] [Indexed: 10/26/2022] Open
Abstract
Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5/GPR49) is highly expressed in adult stem cells of various tissues, such as intestine, hair follicles, and stomach. LGR5 is also overexpressed in some colon and ovarian tumors. Recent reports show that R-spondin (RSPO) family ligands bind to and activate LGR5, enhancing canonical Wnt signaling via the interaction with LRP5/6 and Frizzled. The identity of heterotrimeric G-proteins coupled to LGR5, however, remains unclear. Here, we show that Rho GTPase is a downstream target of LGR5. Overexpression of LGR5 induced SRF-RE luciferase activity, a reporter of Rho signaling. RSPOs, ligands for LGR4, LGR5, and LGR6, however, did not induce SRF-RE reporter activity in the presence of LGR5. Consistently, LGR5-induced activity of the SRF-RE reporter was inhibited by Rho inhibitor C3 transferase and RhoA N19 mutant, and knockdown of Gα12/13 genes blocked the reporter activity induced by LGR5. In addition, focal adhesion kinase, NF-κB and c-fos, targets of Rho GTPase, were shown to be regulated by LGR5. Here, we have demonstrated, for the first time, that LGR5 is coupled to the Rho pathway through G12/13 signaling.
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Affiliation(s)
- Mi So Kwon
- Targeted Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongwon 363-883, Korea
- Biomolecular Science Major, University of Science and Technology, Daejeon 305-350, Korea
| | - Bi-oh Park
- Targeted Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongwon 363-883, Korea
| | - Ho Min Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Sunhong Kim
- Targeted Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongwon 363-883, Korea
- Biomolecular Science Major, University of Science and Technology, Daejeon 305-350, Korea
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45
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Abstract
The ultimate success of global efforts to exploit adult stem cells for regenerative medicine will depend heavily on the availability of robust, highly selective stem cell surface markers that facilitate the isolation of stem cells from human tissues. Any subsequent expansion or manipulation of isolated stem cells will also require an intimate knowledge of the mechanisms that regulate these cells, to ensure maintenance of their regenerative capacities and to minimize the risk of introducing undesirable growth traits that could pose health risks for patients. A subclass of leucine-rich repeat-containing G-protein-coupled receptor (Lgr) proteins has recently gained prominence as adult stem cell markers with crucial roles in maintaining stem cell functions. Here, we discuss the major impact that their discovery has had on our understanding of adult stem cell biology in various self-renewing tissues and in accelerating progress towards the development of effective stem cell therapies.
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Affiliation(s)
- Nick Barker
- Institute of Medical Biology, 8A Biomedical Grove, 06-06 Immunos, 138648 Singapore.
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46
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Wang D, Huang B, Zhang S, Yu X, Wu W, Wang X. Structural basis for R-spondin recognition by LGR4/5/6 receptors. Genes Dev 2013; 27:1339-44. [PMID: 23756652 DOI: 10.1101/gad.219360.113] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The R-spondin (RSPO) family of secreted proteins (RSPO1-RSPO4) has pleiotropic functions in development and stem cell growth by strongly enhancing Wnt pathway activation. Recently, leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4), LGR5, and LGR6 have been identified as receptors for RSPOs. Here we report the complex structure of the LGR4 extracellular domain (ECD) with the RSPO1 N-terminal fragment (RSPO1-2F) containing two adjacent furin-like cysteine-rich domains (FU-CRDs). The LGR4-ECD adopts the anticipated TLR horseshoe structure and uses its concave surface close to the N termini to bind RSPO1-2F. Both the FU-CRD1 and FU-CRD2 domains of RSPO1 contribute to LGR4 interaction, and binding and cellular assays identified critical RSPO1 residues for its biological activities. Our results define the molecular mechanism by which the LGR4/5/6 receptors recognize RSPOs and also provide structural insights into the signaling difference between the LGR4/5/6 receptors and other members in the LGR family.
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Affiliation(s)
- Dongli Wang
- Ministry of Education Key Laboratory of Protein Science, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China
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47
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Qian Y, Liu S, Guan Y, Pan H, Guan X, Qiu Z, Li L, Gao N, Zhao Y, Li X, Lu Y, Liu M, Li D. Lgr4-mediated Wnt/β-catenin signaling in peritubular myoid cells is essential for spermatogenesis. Development 2013; 140:1751-61. [PMID: 23533175 DOI: 10.1242/dev.093641] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Peritubular myoid cells (PMCs) are myofibroblast-like cells that surround the seminiferous tubules and play essential roles in male fertility. How these cells modulate spermatogenesis and the signaling pathways that are involved are largely unknown. Here we report that Lgr4 is selectively expressed in mouse PMCs in the testes, and loss of Lgr4 leads to germ cells arresting at meiosis I and then undergoing apoptosis. In PMCs of Lgr4 mutant mice, the expression of androgen receptor, alpha-smooth muscle actin and extracellular matrix proteins was dramatically reduced. Malfunctioning PMCs further affected Sertoli cell nuclear localization and functional protein expression in Lgr4(-/-) mice. In addition, Wnt/β-catenin signaling was activated in wild-type PMCs but attenuated in those of Lgr4(-/-) mice. When Wnt/β-catenin signaling was reactivated by crossing with Apc(min/+) mice or by Gsk3β inhibitor treatment, the Lgr4 deficiency phenotype in testis was partially rescued. Together, these data demonstrate that Lgr4 signaling through Wnt/β-catenin regulates PMCs and is essential for spermatogenesis.
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Affiliation(s)
- Yu Qian
- Institute of Biomedical Sciences, East China Normal University, Shanghai, China
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Cheng Y, Kawamura K, Takae S, Deguchi M, Yang Q, Kuo C, Hsueh AJW. Oocyte-derived R-spondin2 promotes ovarian follicle development. FASEB J 2013; 27:2175-84. [PMID: 23407710 DOI: 10.1096/fj.12-223412] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
R-spondin proteins are adult stem cell growth factors capable of stimulating gut development by activating LGR4, 5, and 6 receptors to promote Wnt signaling. Although multiple Wnt ligands and cognate Frizzled receptors are expressed in the ovary, their physiological roles are unclear. Based on bioinformatic and in situ hybridization analyses, we demonstrated the exclusive expression of R-spondin2 in oocytes of ovarian follicles. In cultured somatic cells from preantral follicles, R-spondin2 treatment (ED50: 3 ng/ml) synergized with Wnt3a to stimulate Wnt signaling. In cultured ovarian explants from prepubertal mice containing preantral follicles, treatment with R-spondin2, similar to follicle stimulating hormone, promoted the development of primary follicles to the secondary stage. In vivo administration of an R-spondin agonist stimulated the development of primary follicles to the antral stage in both immature mice and gonadotropin releasing hormone antagonist-treated adult mice. Subsequent treatment with gonadotropins allowed the generation of mature oocytes capable of undergoing early embryonic development and successful pregnancy. Furthermore, R-spondin agonist treatment of immune-deficient mice grafted with human cortical fragments stimulated the development of primary follicles to the secondary stage. Thus, oocyte-derived R-spondin2 is a paracrine factor essential for primary follicle development, and R-spondin agonists could provide a new treatment regimen for infertile women with low responses to the traditional gonadotropin therapy.
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Affiliation(s)
- Yuan Cheng
- Program of Reproductive and Stem Cell Biology, Stanford University School of Medicine, Stanford, CA 94305-5317, USA
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49
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Abstract
The four vertebrate R-spondin proteins are secreted agonists of the canonical Wnt/β-catenin signaling pathway. These proteins are approximately 35 kDa, and are characterized by two amino-terminal furin-like repeats, which are necessary and sufficient for Wnt signal potentiation, and a thrombospondin domain situated more towards the carboxyl terminus that can bind matrix glycosaminoglycans and/or proteoglycans. Although R-spondins are unable to initiate Wnt signaling, they can potently enhance responses to low-dose Wnt proteins. In humans, rare disruptions of the gene encoding R-spondin1 cause a syndrome of XX sex reversal (phenotypic male), palmoplantar keratosis (a thickening of the palms and soles caused by excess keratin formation) and predisposition to squamous cell carcinoma of the skin. Mutations in the gene encoding R-spondin4 cause anonychia (absence or hypoplasia of nails on fingers and toes). Recently, leucine-rich repeat-containing G-protein-coupled receptor (Lgr)4, Lgr5 and Lgr6, three closely related orphans of the leucine-rich repeat family of G-protein-coupled receptors, have been identified as receptors for R-spondins. Lgr5 and Lgr6 are markers for adult stem cells. Because R-spondins are potent stimulators of adult stem cell proliferation in vivo and in vitro, these findings might guide the therapeutic use of R-spondins in regenerative medicine.
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Affiliation(s)
- Wim B M de Lau
- Hubrecht Institute, Developmental Biology and Stem Cell Research, Royal Netherlands Academy of Arts and Sciences, University Medical Center Utrecht, The Netherlands
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Rizk P, Barker N. Gut stem cells in tissue renewal and disease: methods, markers, and myths. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2012; 4:475-96. [DOI: 10.1002/wsbm.1176] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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