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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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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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Liang F, Zhang H, Cheng D, Gao H, Wang J, Yue J, Zhang N, Wang J, Wang Z, Zhao B. Ablation of LGR4 signaling enhances radiation sensitivity of prostate cancer cells. Life Sci 2020; 265:118737. [PMID: 33171177 DOI: 10.1016/j.lfs.2020.118737] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 12/14/2022]
Abstract
AIM Our previous study has shown that leucine-rich repeat containing GPCR-4 (LGR4, or GPR48) LGR4 plays a role in cell migration, invasion, proliferation and apoptosis of prostate cancer (PCa). In this study, we aimed to explore whether LGR4 would affect radiation response in PCa. MATERIALS AND METHODS LGR4 expression was silenced by shRNA transfection. qRT-PCR was employed to determine mRNA expression of LGR4 and DNA damage repair genes. Western blot was used to evaluate protein expression of LGR4, RSPO1-4, androgen receptor (AR), cyclic AMP response-element binding protein (CREB1), γH2A.X, and H2A.X. Cell proliferation was detected by CCK-8 assay and apoptosis was assayed by flow cytometry. Additionally, a xenograft model was also established to validate the role of LGR4 in PCa cells after radiation. KEY FINDINGS LGR4 expression was enhanced in PCa cells by radiation treatment in dose- and time-dependent means. RSPO1-4 were also upregulated post-radiation. Furthermore, LGR4 knockdown exacerbated apoptosis, reduced cell viabilities and strengthened nuclear γH2A.X staining in AR positive PCa cells but not in AR negative cells in the presence of radiation. Likewise, LGR4 ablation diminished AR and CREB1 expression induced by radiation. In contrast, RSPO1 stimulation augmented cell viabilities, promoted AR and CREB1 expression, and upregulated DNA repair gene expression, which could be reversed by enzalutamide, except for AR expression. Additionally, LGR4 knockdown further suppressed tumor growth and AR/CREB1 expression but enhanced γH2A.X expression in xenografts. SIGNIFICANCE In all, our study suggested that LGR4 might serve as an important regulator of radiation sensitivity in PCa.
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Affiliation(s)
- Fang Liang
- Department of Oncology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China.
| | - Hao Zhang
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China
| | - Duo Cheng
- Department of Oncology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China
| | - Hui Gao
- Department of Oncology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China
| | - Junyong Wang
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China
| | - Junmin Yue
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China
| | - Nan Zhang
- Department of Oncology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China
| | - Jingjing Wang
- Department of Oncology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China
| | - Zhaoyang Wang
- Department of Urology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China
| | - Beibei Zhao
- Department of Oncology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou Central Hospital, Zhengzhou, China
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Yang H, Yang C, Zhu Q, Wei M, Li Y, Cheng J, Liu F, Wu Y, Zhang J, Zhang C, Wu H. Rack1 Controls Parallel Fiber-Purkinje Cell Synaptogenesis and Synaptic Transmission. Front Cell Neurosci 2019; 13:539. [PMID: 31920545 PMCID: PMC6927999 DOI: 10.3389/fncel.2019.00539] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/20/2019] [Indexed: 01/01/2023] Open
Abstract
Purkinje cells (PCs) in the cerebellum receive two excitatory afferents including granule cells-derived parallel fiber (PF) and the climbing fiber. Scaffolding protein Rack1 is highly expressed in the cerebellar PCs. Here, we found delayed formation of specific cerebellar vermis lobule and impaired motor coordination in PC-specific Rack1 conditional knockout mice. Our studies further revealed that Rack1 is essential for PF–PC synapse formation. In addition, Rack1 plays a critical role in regulating synaptic plasticity and long-term depression (LTD) induction of PF–PC synapses without changing the expression of postsynaptic proteins. Together, we have discovered Rack1 as the crucial molecule that controls PF–PC synaptogenesis and synaptic plasticity. Our studies provide a novel molecular insight into the mechanisms underlying the neural development and neuroplasticity in the cerebellum.
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Affiliation(s)
- Haihong Yang
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China.,Department of Anesthesiology, The General Hospital of Western Theater Command, Chengdu, China
| | - Chaojuan Yang
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Qian Zhu
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Mengping Wei
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Ying Li
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Juanxian Cheng
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Fengjiao Liu
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Yan Wu
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Jiyan Zhang
- Department of Neuroimmunology and Antibody Engineering, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Chen Zhang
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Haitao Wu
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China.,Chinese Institute for Brain Research, Beijing, China.,Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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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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Abstract
Purkinje cells (PC) control deep cerebellar nuclei (DCN), which in turn inhibit inferior olive nucleus, closing a positive feedback loop via climbing fibers. PC highly express potassium BK channels but their contribution to the olivo-cerebellar loop is not clear. Using multiple-unit recordings in alert mice we found in that selective deletion of BK channels in PC induces a decrease in their simple spike firing with a beta-range bursting pattern and fast intraburst frequency (~200 Hz). To determine the impact of this abnormal rhythm on the olivo-cerebellar loop we analyzed simultaneous rhythmicity in different cerebellar structures. We found that this abnormal PC rhythmicity is transmitted to DCN neurons with no effect on their mean firing frequency. Long term depression at the parallel-PC synapses was altered and the intra-burst complex spike spikelets frequency was increased without modification of the mean complex spike frequency in BK-PC−/− mice. We argue that the ataxia present in these conditional knockout mice could be explained by rhythmic disruptions transmitted from mutant PC to DCN but not by rate code modification only. This suggests a neuronal mechanism for ataxia with possible implications for human disease.
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Yue Z, Yuan Z, Zeng L, Wang Y, Lai L, Li J, Sun P, Xue X, Qi J, Yang Z, Zheng Y, Fang Y, Li D, Siwko S, Li Y, Luo J, Liu M. LGR4 modulates breast cancer initiation, metastasis, and cancer stem cells. FASEB J 2017; 32:2422-2437. [PMID: 29269400 DOI: 10.1096/fj.201700897r] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The fourth member of the leucine-rich repeat-containing GPCR family (LGR4, frequently referred to as GPR48) and its cognate ligands, R-spondins (RSPOs) play crucial roles in the development of multiple organs as well as the survival of adult stem cells by activation of canonical Wnt signaling. Wnt/β-catenin signaling acts to regulate breast cancer; however, the molecular mechanisms determining its spatiotemporal regulation are largely unknown. In this study, we identified LGR4 as a master controller of Wnt/β-catenin signaling-mediated breast cancer tumorigenesis, metastasis, and cancer stem cell (CSC) maintenance. LGR4 expression in breast tumors correlated with poor prognosis. Either Lgr4 haploinsufficiency or mammary-specific deletion inhibited mouse mammary tumor virus (MMTV)- PyMT- and MMTV- Wnt1-driven mammary tumorigenesis and metastasis. Moreover, LGR4 down-regulation decreased in vitro migration and in vivo xenograft tumor growth and lung metastasis. Furthermore, Lgr4 deletion in MMTV- Wnt1 tumor cells or knockdown in human breast cancer cells decreased the number of functional CSCs by ∼90%. Canonical Wnt signaling was impaired in LGR4-deficient breast cancer cells, and LGR4 knockdown resulted in increased E-cadherin and decreased expression of N-cadherin and snail transcription factor -2 ( SNAI2) (also called SLUG), implicating LGR4 in regulation of epithelial-mesenchymal transition. Our findings support a crucial role of the Wnt signaling component LGR4 in breast cancer initiation, metastasis, and breast CSCs.-Yue, Z., Yuan, Z., Zeng, L., Wang, Y., Lai, L., Li, J., Sun, P., Xue, X., Qi, J., Yang, Z., Zheng, Y., Fang, Y., Li, D., Siwko, S., Li, Y., Luo, J., Liu, M. LGR4 modulates breast cancer initiation, metastasis, and cancer stem cells.
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Affiliation(s)
- Zhiying Yue
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Zengjin Yuan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Li Zeng
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.,Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
| | - Ying Wang
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
| | - Li Lai
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
| | - Jing Li
- East China Normal University Joint Center for Translational Medicine, Shanghai Fengxian District Central Hospital, Shanghai, China
| | - Peng Sun
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Xiwen Xue
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Junyi Qi
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Zhengfeng Yang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Yansen Zheng
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Yuanzhang Fang
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Stefan Siwko
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
| | - Yi Li
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Jian Luo
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.,Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, Texas, USA
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8
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Khan MZ, He L. Neuro-psychopharmacological perspective of Orphan receptors of Rhodopsin (class A) family of G protein-coupled receptors. Psychopharmacology (Berl) 2017; 234:1181-1207. [PMID: 28289782 DOI: 10.1007/s00213-017-4586-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 02/27/2017] [Indexed: 12/28/2022]
Abstract
BACKGROUND In the central nervous system (CNS), G protein-coupled receptors (GPCRs) are the most fruitful targets for neuropsychopharmacological drug development. Rhodopsin (class A) is the most studied class of GPCR and includes orphan receptors for which the endogenous ligand is not known or is unclear. Characterization of orphan GPCRs has proven to be challenging, and the production pace of GPCR-based drugs has been incredibly slow. OBJECTIVE Determination of the functions of these receptors may provide unexpected insight into physiological and neuropathological processes. Advances in various methods and techniques to investigate orphan receptors including in situ hybridization and knockdown/knockout (KD/KO) showed extensive expression of these receptors in the mammalian brain and unmasked their physiological and neuropathological roles. Due to these rapid progress and development, orphan GPCRs are rising as a new and promising class of drug targets for neurodegenerative diseases and psychiatric disorders. CONCLUSION This review presents a neuropsychopharmacological perspective of 26 orphan receptors of rhodopsin (class A) family, namely GPR3, GPR6, GPR12, GPR17, GPR26, GPR35, GPR39, GPR48, GPR49, GPR50, GPR52, GPR55, GPR61, GPR62, GPR63, GPR68, GPR75, GPR78, GPR83, GPR84, GPR85, GPR88, GPR153, GPR162, GPR171, and TAAR6. We discussed the expression of these receptors in mammalian brain and their physiological roles. Furthermore, we have briefly highlighted their roles in neurodegenerative diseases and psychiatric disorders including Alzheimer's disease, Parkinson's disease, neuroinflammation, inflammatory pain, bipolar and schizophrenic disorders, epilepsy, anxiety, and depression.
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Affiliation(s)
- Muhammad Zahid Khan
- Department of Pharmacology, China Pharmaceutical University, No. 24 Tong Jia Xiang, Nanjing, Jiangsu Province, 210009, China.
| | - Ling He
- Department of Pharmacology, China Pharmaceutical University, No. 24 Tong Jia Xiang, Nanjing, Jiangsu Province, 210009, China
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9
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Zhu JW, Li YF, Wang ZT, Jia WQ, Xu RX. Toll-Like Receptor 4 Deficiency Impairs Motor Coordination. Front Neurosci 2016; 10:33. [PMID: 26909014 PMCID: PMC4754460 DOI: 10.3389/fnins.2016.00033] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/27/2016] [Indexed: 11/13/2022] Open
Abstract
The cerebellum plays an essential role in balance and motor coordination. Purkinje cells (PCs) are the sole output neurons of the cerebellar cortex and are critical for the execution of its functions, including motor coordination. Toll-like receptor (TLR) 4 is involved in the innate immune response and is abundantly expressed in the central nervous system; however, little is known about its role in cerebellum-related motor functions. To address this question, we evaluated motor behavior in TLR4 deficient mice. We found that TLR4(-∕-) mice showed impaired motor coordination. Morphological analyses revealed that TLR4 deficiency was associated with a reduction in the thickness of the molecular layer of the cerebellum. TLR4 was highly expressed in PCs but not in Bergmann glia or cerebellar granule cells; however, loss of TLR4 decreased the number of PCs. These findings suggest a novel role for TLR4 in cerebellum-related motor coordination through maintenance of the PC population.
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Affiliation(s)
- Jian-Wei Zhu
- Affiliated Bayi Brain Hospital, Military General Hospital of Beijing PLA, Southern Medical University Beijing, China
| | - Yi-Fei Li
- Affiliated Bayi Brain Hospital, Military General Hospital of Beijing PLA, Southern Medical University Beijing, China
| | - Zhao-Tao Wang
- Affiliated Bayi Brain Hospital, Military General Hospital of Beijing PLA, Southern Medical University Beijing, China
| | - Wei-Qiang Jia
- Affiliated Bayi Brain Hospital, Military General Hospital of Beijing PLA, Southern Medical University Beijing, China
| | - Ru-Xiang Xu
- Affiliated Bayi Brain Hospital, Military General Hospital of Beijing PLA, Southern Medical University Beijing, China
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10
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Snyder JC, Rochelle LK, Marion S, Lyerly HK, Barak LS, Caron MG. Lgr4 and Lgr5 drive the formation of long actin-rich cytoneme-like membrane protrusions. J Cell Sci 2015; 128:1230-40. [PMID: 25653388 PMCID: PMC4359926 DOI: 10.1242/jcs.166322] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/27/2015] [Indexed: 01/06/2023] Open
Abstract
Embryonic development and adult tissue homeostasis require precise information exchange between cells and their microenvironment to coordinate cell behavior. A specialized class of ultra-long actin-rich filopodia, termed cytonemes, provides one mechanism for this spatiotemporal regulation of extracellular cues. We provide here a mechanism whereby the stem-cell marker Lgr5, and its family member Lgr4, promote the formation of cytonemes. Lgr4- and Lgr5-induced cytonemes exceed lengths of 80 µm, are generated through stabilization of nascent filopodia from an underlying lamellipodial-like network and functionally provide a pipeline for the transit of signaling effectors. As proof-of-principle, we demonstrate that Lgr5-induced cytonemes act as conduits for cell signaling by demonstrating that the actin motor and filopodial cargo carrier protein myosin X (Myo10) and the G-protein-coupled receptor (GPCR) signaling effector β-arrestin-2 (Arrb2) transit into cytonemes. This work delineates a biological function for Lgr4 and Lgr5 and provides the rationale to fully investigate Lgr4 and Lgr5 function and cytonemes in mammalian stem cell and cancer stem cell behavior.
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Affiliation(s)
- Joshua C Snyder
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Lauren K Rochelle
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Sébastien Marion
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - H Kim Lyerly
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | - Larry S Barak
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Marc G Caron
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
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