1
|
Burke KP, Chaudhri A, Freeman GJ, Sharpe AH. The B7:CD28 family and friends: Unraveling coinhibitory interactions. Immunity 2024; 57:223-244. [PMID: 38354702 PMCID: PMC10889489 DOI: 10.1016/j.immuni.2024.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/17/2024] [Accepted: 01/17/2024] [Indexed: 02/16/2024]
Abstract
Immune responses must be tightly regulated to ensure both optimal protective immunity and tolerance. Costimulatory pathways within the B7:CD28 family provide essential signals for optimal T cell activation and clonal expansion. They provide crucial inhibitory signals that maintain immune homeostasis, control resolution of inflammation, regulate host defense, and promote tolerance to prevent autoimmunity. Tumors and chronic pathogens can exploit these pathways to evade eradication by the immune system. Advances in understanding B7:CD28 pathways have ushered in a new era of immunotherapy with effective drugs to treat cancer, autoimmune diseases, infectious diseases, and transplant rejection. Here, we discuss current understanding of the mechanisms underlying the coinhibitory functions of CTLA-4, PD-1, PD-L1:B7-1 and PD-L2:RGMb interactions and less studied B7 family members, including HHLA2, VISTA, BTNL2, and BTN3A1, as well as their overlapping and unique roles in regulating immune responses, and the therapeutic potential of these insights.
Collapse
Affiliation(s)
- Kelly P Burke
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA; Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Apoorvi Chaudhri
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | - Gordon J Freeman
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | - Arlene H Sharpe
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA; Brigham and Women's Hospital, Boston, MA 02115, USA.
| |
Collapse
|
2
|
Yao LL, Hu JX, Li Q, Lee D, Ren X, Zhang JS, Sun D, Zhang HS, Wang YG, Mei L, Xiong WC. Astrocytic neogenin/netrin-1 pathway promotes blood vessel homeostasis and function in mouse cortex. J Clin Invest 2021; 130:6490-6509. [PMID: 32853179 DOI: 10.1172/jci132372] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 08/20/2020] [Indexed: 12/14/2022] Open
Abstract
Astrocytes have multiple functions in the brain, including affecting blood vessel (BV) homeostasis and function. However, the underlying mechanisms remain elusive. Here, we provide evidence that astrocytic neogenin (NEO1), a member of deleted in colorectal cancer (DCC) family netrin receptors, is involved in blood vessel homeostasis and function. Mice with Neo1 depletion in astrocytes exhibited clustered astrocyte distribution and increased BVs in their cortices. These BVs were leaky, with reduced blood flow, disrupted vascular basement membranes (vBMs), decreased pericytes, impaired endothelial cell (EC) barrier, and elevated tip EC proliferation. Increased proliferation was also detected in cultured ECs exposed to the conditioned medium (CM) of NEO1-depleted astrocytes. Further screening for angiogenetic factors in the CM identified netrin-1 (NTN1), whose expression was decreased in NEO1-depleted cortical astrocytes. Adding NTN1 into the CM of NEO1-depleted astrocytes attenuated EC proliferation. Expressing NTN1 in NEO1 mutant cortical astrocytes ameliorated phenotypes in blood-brain barrier (BBB), EC, and astrocyte distribution. NTN1 depletion in astrocytes resulted in BV/BBB deficits in the cortex similar to those in Neo1 mutant mice. In aggregate, these results uncovered an unrecognized pathway, astrocytic NEO1 to NTN1, not only regulating astrocyte distribution, but also promoting cortical BV homeostasis and function.
Collapse
Affiliation(s)
- Ling-Ling Yao
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.,Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Jin-Xia Hu
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.,Institute of Stroke Center and Department of Neurology, Xuzhou Medical University, The Affiliated Hospital of Xuzhou Medical University, Jiangsu, China
| | - Qiang Li
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.,Department of Hand Surgery, China-Japan Union Hospital, Jilin University, Changchun, China
| | - Daehoon Lee
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Xiao Ren
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.,Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jun-Shi Zhang
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.,Department of Neurology, Huaihe Hospital, Henan University, Kaifeng, Henan, China
| | - Dong Sun
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.,Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Hong-Sheng Zhang
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.,Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Yong-Gang Wang
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Lin Mei
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.,Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Wen-Cheng Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.,Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| |
Collapse
|
3
|
Pauken KE, Torchia JA, Chaudhri A, Sharpe AH, Freeman GJ. Emerging concepts in PD-1 checkpoint biology. Semin Immunol 2021; 52:101480. [PMID: 34006473 PMCID: PMC8545711 DOI: 10.1016/j.smim.2021.101480] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 05/03/2021] [Indexed: 12/11/2022]
Abstract
The PD-1 pathway is a cornerstone in immune regulation. While the PD-1 pathway has received considerable attention for its role in contributing to the maintenance of T cell exhaustion in chronic infection and cancer, the PD-1 pathway plays diverse roles in regulating host immunity beyond T cell exhaustion. Here, we discuss emerging concepts in the PD-1 pathway, including (1) the impact of PD-1 inhibitors on diverse T cell differentiation states including effector and memory T cell development during acute infection, as well as T cell exhaustion during chronic infection and cancer, (2) the role of PD-1 in regulating Treg cells, NK cells, and ILCs, and (3) the functions of PD-L1/B7-1 and PD-L2/RGMb/neogenin interactions. We then discuss the emerging use of neoadjuvant PD-1 blockade in the treatment of early-stage cancers and how the timing of PD-1 blockade may improve clinical outcomes. The diverse binding partners of PD-1 and its associated ligands, broad expression patterns of the receptors and ligands, differential impact of PD-1 modulation on cells depending on location and state of differentiation, and timing of PD-1 blockade add additional layers of complexity to the PD-1 pathway, and are important considerations for improving the efficacy and safety of PD-1 pathway therapeutics.
Collapse
Affiliation(s)
- Kristen E Pauken
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA; Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - James A Torchia
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, 02215, USA
| | - Apoorvi Chaudhri
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, 02215, USA; Department of Melanoma Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA; The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
| | - Arlene H Sharpe
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA; Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA; Department of Pathology, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - Gordon J Freeman
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, 02215, USA.
| |
Collapse
|
4
|
Yu S, Leung KM, Kim HY, Umetsu SE, Xiao Y, Albacker LA, Lee HJ, Umetsu DT, Freeman GJ, DeKruyff RH. Blockade of RGMb inhibits allergen-induced airways disease. J Allergy Clin Immunol 2019; 144:94-108.e11. [PMID: 30703386 PMCID: PMC8088837 DOI: 10.1016/j.jaci.2018.12.1022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 11/20/2018] [Accepted: 12/07/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND Allergic asthma causes morbidity in many subjects, and novel precision-directed treatments would be valuable. OBJECTIVE We sought to examine the role of a novel innate molecule, repulsive guidance molecule b (RGMb), in murine models of allergic asthma. METHODS In models of allergic asthma using ovalbumin or cockroach allergen, mice were treated with anti-RGMb or control mAb and examined for airway inflammation and airway hyperreactivity (AHR), a cardinal feature of asthma. The mechanisms by which RGMb causes airways disease were also examined. RESULTS We found that blockade of RGMb by treatment with anti-RGMb mAb effectively blocked the development of airway inflammation and AHR. Importantly, blockade of RGMb completely blocked the development of airway inflammation and AHR, even if treatment occurred only during the challenge (effector) phase. IL-25 played an important role in these models of asthma because IL-25 receptor-deficient mice did not develop disease after sensitization and challenge with allergen. RGMb was expressed primarily by innate cells in the lungs, including bronchial epithelial cells (known producers of IL-25), activated eosinophils, and interstitial macrophages, which in the inflamed lung expressed the IL-25 receptor and produced IL-5 and IL-13. We also found that neogenin, the canonical receptor for RGMb, was expressed by interstitial macrophages and bronchial epithelial cells in the inflamed lung, suggesting that an innate RGMb-neogenin axis might modulate allergic asthma. CONCLUSIONS These results demonstrate an important role for a novel innate pathway in regulating type 2 inflammation in patients with allergic asthma involving RGMb and RGMb-expressing cells, such as interstitial macrophages and bronchial epithelial cells. Moreover, targeting this previously unappreciated innate pathway might provide an important treatment option for allergic asthma.
Collapse
Affiliation(s)
- Sanhong Yu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Mass; Boston Children's Hospital, Harvard Medical School, Boston, Mass
| | - Krystle M Leung
- Boston Children's Hospital, Harvard Medical School, Boston, Mass
| | - Hye-Young Kim
- Boston Children's Hospital, Harvard Medical School, Boston, Mass
| | - Sarah E Umetsu
- Department of Pathology, University of California, San Francisco, Calif
| | - Yanping Xiao
- Department of Medical Oncology, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Mass
| | - Lee A Albacker
- Boston Children's Hospital, Harvard Medical School, Boston, Mass; Immunology Program, Harvard Medical School, Boston, Mass
| | - Hyun-Jun Lee
- Boston Children's Hospital, Harvard Medical School, Boston, Mass
| | - Dale T Umetsu
- Boston Children's Hospital, Harvard Medical School, Boston, Mass
| | - Gordon J Freeman
- Department of Medical Oncology, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Mass
| | - Rosemarie H DeKruyff
- Boston Children's Hospital, Harvard Medical School, Boston, Mass; Sean N Parker Center for Allergy and Asthma Research, Department of Medicine, Stanford University, Stanford, Calif.
| |
Collapse
|
5
|
Ren T, Zheng B, Huang Y, Wang S, Bao X, Liu K, Guo W. Osteosarcoma cell intrinsic PD-L2 signals promote invasion and metastasis via the RhoA-ROCK-LIMK2 and autophagy pathways. Cell Death Dis 2019; 10:261. [PMID: 30886151 PMCID: PMC6423010 DOI: 10.1038/s41419-019-1497-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 01/29/2019] [Accepted: 03/04/2019] [Indexed: 12/15/2022]
Abstract
Known as co-stimulatory molecule, programmed death ligand-2 (PD-L2) contributes to T-cell exhaustion by interaction with programmed death-1 (PD-1) receptor, but its tumor cell-intrinsic signal effects have been little investigated. PD-L2 expression was detected by immunohistochemistry in 18 pairs of primary osteosarcoma tissues and matching lung metastasis tissues. We also investigated the effects of PD-L2 knockdown on osteosarcoma both in vitro and in vivo. In our study, PD-L2 expression was elevated in lung metastases compared with primary osteosarcoma according to an immunohistochemistry assay. Wound-healing and transwell assays revealed that PD-L2 knockdown leaded to inhibition of migration and invasion of human osteosarcoma cells in vitro. Mechanistically, we demonstrated that PD-L2 knockdown attenuated migration and invasion by inactivating RhoA-ROCK-LIMK2 signaling, suppressing epithelial–mesenchymal transition (EMT), and inhibiting autophagy by decreasing beclin-1 expression. In support of these observations, beclin-1 knockdown also inhibited activation of the RhoA-ROCK-LIMK2 pathway, leading to autophagy inhibition-induced blockade of migration and invasion. Depletion of PD-L2 in KHOS cells markedly weakens pulmonary metastatic potential in vivo by orthotopic transplantation of nude mice. Our study reveals a pro-metastatic functional mechanism for PD-L2 in osteosarcoma. Furthermore, we demonstrate a regulatory role for PD-L2 on autophagy, as well as a relationship between autophagy and metastasis in osteosarcoma, which may represent a potential therapeutic target for osteosarcoma.
Collapse
Affiliation(s)
- Tingting Ren
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China.,Beijing Key Laboratory of Musculoskeletal Tumor, Beijing, People's Republic of China
| | - Bingxin Zheng
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China.,Beijing Key Laboratory of Musculoskeletal Tumor, Beijing, People's Republic of China.,Department of Orthopedic Surgery, The Affiliated Hospital of Qingdao University, Qingdao, People's Republic of China
| | - Yi Huang
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China.,Beijing Key Laboratory of Musculoskeletal Tumor, Beijing, People's Republic of China
| | - Shidong Wang
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China.,Beijing Key Laboratory of Musculoskeletal Tumor, Beijing, People's Republic of China
| | - Xing Bao
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China.,Beijing Key Laboratory of Musculoskeletal Tumor, Beijing, People's Republic of China
| | - Kuisheng Liu
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China.,Beijing Key Laboratory of Musculoskeletal Tumor, Beijing, People's Republic of China
| | - Wei Guo
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China. .,Beijing Key Laboratory of Musculoskeletal Tumor, Beijing, People's Republic of China.
| |
Collapse
|
6
|
Cwetsch AW, Pinto B, Savardi A, Cancedda L. In vivo methods for acute modulation of gene expression in the central nervous system. Prog Neurobiol 2018; 168:69-85. [PMID: 29694844 PMCID: PMC6080705 DOI: 10.1016/j.pneurobio.2018.04.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 04/17/2018] [Accepted: 04/20/2018] [Indexed: 12/17/2022]
Abstract
Accurate and timely expression of specific genes guarantees the healthy development and function of the brain. Indeed, variations in the correct amount or timing of gene expression lead to improper development and/or pathological conditions. Almost forty years after the first successful gene transfection in in vitro cell cultures, it is currently possible to regulate gene expression in an area-specific manner at any step of central nervous system development and in adulthood in experimental animals in vivo, even overcoming the very poor accessibility of the brain. Here, we will review the diverse approaches for acute gene transfer in vivo, highlighting their advantages and disadvantages with respect to the efficiency and specificity of transfection as well as to brain accessibility. In particular, we will present well-established chemical, physical and virus-based approaches suitable for different animal models, pointing out their current and future possible applications in basic and translational research as well as in gene therapy.
Collapse
Affiliation(s)
- Andrzej W Cwetsch
- Local Micro-environment and Brain Development Laboratory, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy; Università degli Studi di Genova, Via Balbi, 5, 16126 Genova, Italy
| | - Bruno Pinto
- Local Micro-environment and Brain Development Laboratory, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy; Bio@SNS, Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Annalisa Savardi
- Local Micro-environment and Brain Development Laboratory, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy; Università degli Studi di Genova, Via Balbi, 5, 16126 Genova, Italy
| | - Laura Cancedda
- Local Micro-environment and Brain Development Laboratory, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy; DulbeccoTelethon Institute, Italy.
| |
Collapse
|
7
|
Expression of RGMb in brain tissue of MCAO rats and its relationship with axonal regeneration. J Neurol Sci 2017; 383:79-86. [DOI: 10.1016/j.jns.2017.10.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 11/24/2022]
|
8
|
Kam JWK, Dumontier E, Baim C, Brignall AC, Mendes da Silva D, Cowan M, Kennedy TE, Cloutier JF. RGMB and neogenin control cell differentiation in the developing olfactory epithelium. Development 2017; 143:1534-46. [PMID: 27143755 DOI: 10.1242/dev.118638] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/29/2016] [Indexed: 12/25/2022]
Abstract
Cellular interactions are key for the differentiation of distinct cell types within developing epithelia, yet the molecular mechanisms engaged in these interactions remain poorly understood. In the developing olfactory epithelium (OE), neural stem/progenitor cells give rise to odorant-detecting olfactory receptor neurons (ORNs) and glial-like sustentacular (SUS) cells. Here, we show in mice that the transmembrane receptor neogenin (NEO1) and its membrane-bound ligand RGMB control the balance of neurons and glial cells produced in the OE. In this layered epithelium, neogenin is expressed in progenitor cells, while RGMB is restricted to adjacent newly born ORNs. Ablation of Rgmb via gene-targeting increases the number of dividing progenitor cells in the OE and leads to supernumerary SUS cells. Neogenin loss-of-function phenocopies these effects observed in Rgmb(-/-) mice, supporting the proposal that RGMB-neogenin signaling regulates progenitor cell numbers and SUS cell production. Interestingly, Neo1(-/-) mice also exhibit increased apoptosis of ORNs, implicating additional ligands in the neogenin-dependent survival of ORNs. Thus, our results indicate that RGMB-neogenin-mediated cell-cell interactions between newly born neurons and progenitor cells control the ratio of glia and neurons produced in the OE.
Collapse
Affiliation(s)
- Joseph Wai Keung Kam
- Montreal Neurological Institute, 3801 University, Montréal, Québec, Canada H3A 2B4 Department of Neurology and Neurosurgery, McGill University, 3801 University, Montréal, Québec, Canada H3A 2B4
| | - Emilie Dumontier
- Montreal Neurological Institute, 3801 University, Montréal, Québec, Canada H3A 2B4 Department of Neurology and Neurosurgery, McGill University, 3801 University, Montréal, Québec, Canada H3A 2B4
| | - Christopher Baim
- Montreal Neurological Institute, 3801 University, Montréal, Québec, Canada H3A 2B4 Department of Neurology and Neurosurgery, McGill University, 3801 University, Montréal, Québec, Canada H3A 2B4
| | - Alexandra C Brignall
- Montreal Neurological Institute, 3801 University, Montréal, Québec, Canada H3A 2B4 Department of Neurology and Neurosurgery, McGill University, 3801 University, Montréal, Québec, Canada H3A 2B4
| | - David Mendes da Silva
- Montreal Neurological Institute, 3801 University, Montréal, Québec, Canada H3A 2B4 Center for Neuroscience and Cell Biology and Department of Life Sciences, University of Coimbra, Rua Larga, Coimbra 3004-517, Portugal
| | - Mitra Cowan
- Centre de Recherches du Centre Hospitalier de l'Université de Montréal, 900 rue Saint-Denis, Montréal, Canada H2X 0A9
| | - Timothy E Kennedy
- Montreal Neurological Institute, 3801 University, Montréal, Québec, Canada H3A 2B4 Department of Neurology and Neurosurgery, McGill University, 3801 University, Montréal, Québec, Canada H3A 2B4 Department of Anatomy and Cell Biology, McGill University, 3640 University, Montréal, Québec, Canada H3A 0C7
| | - Jean-François Cloutier
- Montreal Neurological Institute, 3801 University, Montréal, Québec, Canada H3A 2B4 Department of Neurology and Neurosurgery, McGill University, 3801 University, Montréal, Québec, Canada H3A 2B4 Department of Anatomy and Cell Biology, McGill University, 3640 University, Montréal, Québec, Canada H3A 0C7
| |
Collapse
|
9
|
Li N, Qiao M, Zhao Q, Zhang P, Song L, Li L, Cui C. Effects of maternal lead exposure on RGMa and RGMb expression in the hippocampus and cerebral cortex of mouse pups. Brain Res Bull 2016; 127:38-46. [DOI: 10.1016/j.brainresbull.2016.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 11/26/2022]
|
10
|
Shi Y, Chen GB, Huang XX, Xiao CX, Wang HH, Li YS, Zhang JF, Li S, Xia Y, Ren JL, Guleng B. Dragon (repulsive guidance molecule b, RGMb) is a novel gene that promotes colorectal cancer growth. Oncotarget 2016; 6:20540-54. [PMID: 26029998 PMCID: PMC4653024 DOI: 10.18632/oncotarget.4110] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 04/21/2015] [Indexed: 12/27/2022] Open
Abstract
Colorectal cancer (CRC) is one of the most commonly diagnosed cancers and a major cause of cancer death. However, the molecular mechanisms underlying CRC initiation, growth and metastasis are poorly understood. Dragon (RGMb), a member of the repulsive guidance molecule (RGM) family, has been recently identified as a co-receptor for bone morphogenetic protein (BMP) signaling, but the role of Dragon in CRC development is undefined. Here, we show that Dragon expression was increased in colon cancer tissues compared to control tissues in CAC mouse model and in human patients. Dragon promoted proliferation of CT26.WT and CMT93 colon cancer cells and accelerated tumor growth in the xenograft mouse model. Dragon's action on colon cancer development was mediated via the BMP4-Smad1/5/8 and Erk1/2 pathways. Therefore, our results have revealed that Dragon is a novel gene that promotes CRC growth through the BMP pathway. Dragon may be exploited as a potential therapeutic target for CRC treatment.
Collapse
Affiliation(s)
- Ying Shi
- Department of Gastroenterology, Zhongshan Hospital, Xiamen University, Xiamen, Fujian Province, China
| | - Guo-Bin Chen
- Department of Gastroenterology, Zhongshan Hospital, Xiamen University, Xiamen, Fujian Province, China
| | - Xiao-Xiao Huang
- Department of Gastroenterology, Zhongshan Hospital, Xiamen University, Xiamen, Fujian Province, China
| | - Chuan-Xing Xiao
- Department of Gastroenterology, Zhongshan Hospital, Xiamen University, Xiamen, Fujian Province, China
| | - Huan-Huan Wang
- Department of Gastroenterology, Zhongshan Hospital, Xiamen University, Xiamen, Fujian Province, China
| | - Ye-Sen Li
- Department of Nuclear Medicine, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian Province, China.,Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen, Fujian Province, China
| | - Jin-Fang Zhang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Shao Li
- MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing, China
| | - Yin Xia
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.,School of Biomedical Sciences Core Laboratory, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Jian-Lin Ren
- Department of Gastroenterology, Zhongshan Hospital, Xiamen University, Xiamen, Fujian Province, China
| | - Bayasi Guleng
- Department of Gastroenterology, Zhongshan Hospital, Xiamen University, Xiamen, Fujian Province, China.,Faculty of Clinical Medicine, Medical College, Xiamen University, Xiamen, Fujian Province, China.,State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian Province, China
| |
Collapse
|
11
|
Javeed N, Tardi NJ, Maher M, Singari S, Edwards KA. Controlled expression of Drosophila homeobox loci using the Hostile takeover system. Dev Dyn 2015; 244:808-25. [PMID: 25820349 PMCID: PMC4449281 DOI: 10.1002/dvdy.24279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 03/12/2015] [Accepted: 03/16/2015] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Hostile takeover (Hto) is a Drosophila protein trapping system that allows the investigator to both induce a gene and tag its product. The Hto transposon carries a GAL4-regulated promoter expressing an exon encoding a FLAG-mCherry tag. Upon expression, the Hto exon can splice to a downstream genomic exon, generating a fusion transcript and tagged protein. RESULTS Using rough-eye phenotypic screens, Hto inserts were recovered at eight homeobox or Pax loci: cut, Drgx/CG34340, Pox neuro, araucan, shaven/D-Pax2, Zn finger homeodomain 2, Sex combs reduced (Scr), and the abdominal-A region. The collection yields diverse misexpression phenotypes. Ectopic Drgx was found to alter the cytoskeleton and cell adhesion in ovary follicle cells. Hto expression of cut, araucan, or shaven gives phenotypes similar to those of the corresponding UAS-cDNA constructs. The cut and Pox neuro phenotypes are suppressed by the corresponding RNAi constructs. The Scr and abdominal-A inserts do not make fusion proteins, but may act by chromatin- or RNA-based mechanisms. CONCLUSIONS Hto can effectively express tagged homeodomain proteins from their endogenous loci; the Minos vector allows inserts to be obtained even in transposon cold-spots. Hto screens may recover homeobox genes at high rates because they are particularly sensitive to misexpression.
Collapse
Affiliation(s)
- Naureen Javeed
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Nicholas J. Tardi
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Maggie Maher
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Swetha Singari
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Kevin A. Edwards
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| |
Collapse
|
12
|
Core AB, Canali S, Babitt JL. Hemojuvelin and bone morphogenetic protein (BMP) signaling in iron homeostasis. Front Pharmacol 2014; 5:104. [PMID: 24860505 PMCID: PMC4026703 DOI: 10.3389/fphar.2014.00104] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/21/2014] [Indexed: 12/13/2022] Open
Abstract
Mutations in hemojuvelin (HJV) are the most common cause of the juvenile-onset form of the iron overload disorder hereditary hemochromatosis. The discovery that HJV functions as a co-receptor for the bone morphogenetic protein (BMP) family of signaling molecules helped to identify this signaling pathway as a central regulator of the key iron hormone hepcidin in the control of systemic iron homeostasis. This review highlights recent work uncovering the mechanism of action of HJV and the BMP-SMAD signaling pathway in regulating hepcidin expression in the liver, as well as additional studies investigating possible extra-hepatic functions of HJV. This review also explores the interaction between HJV, the BMP-SMAD signaling pathway and other regulators of hepcidin expression in systemic iron balance.
Collapse
Affiliation(s)
- Amanda B Core
- Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Program in Anemia Signaling Research Boston, MA, USA
| | - Susanna Canali
- Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Program in Anemia Signaling Research Boston, MA, USA
| | - Jodie L Babitt
- Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Program in Anemia Signaling Research Boston, MA, USA
| |
Collapse
|
13
|
Xiao Y, Yu S, Zhu B, Bedoret D, Bu X, Francisco LM, Hua P, Duke-Cohan JS, Umetsu DT, Sharpe AH, DeKruyff RH, Freeman GJ. RGMb is a novel binding partner for PD-L2 and its engagement with PD-L2 promotes respiratory tolerance. ACTA ACUST UNITED AC 2014; 211:943-59. [PMID: 24752301 PMCID: PMC4010901 DOI: 10.1084/jem.20130790] [Citation(s) in RCA: 242] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Interaction between the inhibitory molecule PD-L2 on dendritic cells and repulsive guidance molecule b (RGMb) on lung macrophages is required to establish respiratory tolerance. We report that programmed death ligand 2 (PD-L2), a known ligand of PD-1, also binds to repulsive guidance molecule b (RGMb), which was originally identified in the nervous system as a co-receptor for bone morphogenetic proteins (BMPs). PD-L2 and BMP-2/4 bind to distinct sites on RGMb. Normal resting lung interstitial macrophages and alveolar epithelial cells express high levels of RGMb mRNA, whereas lung dendritic cells express PD-L2. Blockade of the RGMb–PD-L2 interaction markedly impaired the development of respiratory tolerance by interfering with the initial T cell expansion required for respiratory tolerance. Experiments with PD-L2–deficient mice showed that PD-L2 expression on non–T cells was critical for respiratory tolerance, but expression on T cells was not required. Because PD-L2 binds to both PD-1, which inhibits antitumor immunity, and to RGMb, which regulates respiratory immunity, targeting the PD-L2 pathway has therapeutic potential for asthma, cancer, and other immune-mediated disorders. Understanding this pathway may provide insights into how to optimally modulate the PD-1 pathway in cancer immunotherapy while minimizing adverse events.
Collapse
Affiliation(s)
- Yanping Xiao
- Department of Medical Oncology, Dana-Farber Cancer Institute; 2 Division of Immunology and Department of Pediatrics, Boston Children's Hospital; 3 Department of Microbiology and Immunobiology and 4 Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Xiao Y, Yu S, Zhu B, Bedoret D, Bu X, Francisco LM, Hua P, Duke-Cohan JS, Umetsu DT, Sharpe AH, DeKruyff RH, Freeman GJ. RGMb is a novel binding partner for PD-L2 and its engagement with PD-L2 promotes respiratory tolerance. Mol Immunol 2014; 48:1292-300. [PMID: 24752301 DOI: 10.1016/j.molimm.2010.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 11/17/2010] [Accepted: 12/08/2010] [Indexed: 12/30/2022]
Abstract
We report that programmed death ligand 2 (PD-L2), a known ligand of PD-1, also binds to repulsive guidance molecule b (RGMb), which was originally identified in the nervous system as a co-receptor for bone morphogenetic proteins (BMPs). PD-L2 and BMP-2/4 bind to distinct sites on RGMb. Normal resting lung interstitial macrophages and alveolar epithelial cells express high levels of RGMb mRNA, whereas lung dendritic cells express PD-L2. Blockade of the RGMb-PD-L2 interaction markedly impaired the development of respiratory tolerance by interfering with the initial T cell expansion required for respiratory tolerance. Experiments with PD-L2-deficient mice showed that PD-L2 expression on non-T cells was critical for respiratory tolerance, but expression on T cells was not required. Because PD-L2 binds to both PD-1, which inhibits antitumor immunity, and to RGMb, which regulates respiratory immunity, targeting the PD-L2 pathway has therapeutic potential for asthma, cancer, and other immune-mediated disorders. Understanding this pathway may provide insights into how to optimally modulate the PD-1 pathway in cancer immunotherapy while minimizing adverse events.
Collapse
Affiliation(s)
- Yanping Xiao
- Department of Medical Oncology, Dana-Farber Cancer Institute; 2 Division of Immunology and Department of Pediatrics, Boston Children's Hospital; 3 Department of Microbiology and Immunobiology and 4 Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
3D microenvironment of collagen hydrogel enhances the release of neurotrophic factors from human umbilical cord blood cells and stimulates the neurite outgrowth of human neural precursor cells. Biochem Biophys Res Commun 2014; 447:400-6. [PMID: 24727454 DOI: 10.1016/j.bbrc.2014.03.145] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 03/28/2014] [Indexed: 12/13/2022]
Abstract
The umbilical cord blood (UCB) cells have been reported to secrete therapeutic signals, including a series of neurotrophic factors. This suggests the cell source provides suitable therapeutic environments for nerve regeneration that ultimately finds a possible cell therapy for nerve tissue. In this study, we observe a collagen hydrogel provides human UCB cells a proper 3D environment that stimulates the release of various neurotrophic factors. When compared to 2D culture, the 3D hydrogel culture significantly enhanced the expression of a series of neurotrophic factors, including neurotrophins, nerve growth factor, brain-derived neurotrophic factor, and ciliary neurotrophic factor as verified by the gene and protein analysis. To confirm the effects of neurotrophic factors secretion, we allowed an indirect interaction of the UCB-environment with human neural precursor cells (hNPCs). Results showed significantly enhanced neurite outgrowth of hNPCs. Collectively, our findings demonstrate that the collagen-based 3D hydrogel provides excellent environment for UCB-derived cells to release neurotrophic factors that will be ultimately useful for the neural repair and regeneration purposes.
Collapse
|
16
|
Liu W, Li X, Zhao Y, Meng XM, Wan C, Yang B, Lan HY, Lin HY, Xia Y. Dragon (repulsive guidance molecule RGMb) inhibits E-cadherin expression and induces apoptosis in renal tubular epithelial cells. J Biol Chem 2013; 288:31528-39. [PMID: 24052264 DOI: 10.1074/jbc.m113.517573] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Dragon is one of the three members of the repulsive guidance molecule (RGM) family, i.e. RGMa, RGMb (Dragon), and RGMc (hemojuvelin). We previously identified the RGM members as bone morphogenetic protein (BMP) co-receptors that enhance BMP signaling. Our previous studies found that Dragon is highly expressed in the tubular epithelial cells of mouse kidneys. However, the roles of Dragon in renal epithelial cells are yet to be defined. We now show that overexpression of Dragon increased cell death induced by hypoxia in association with increased cleaved poly(ADP-ribose) polymerase and cleaved caspase-3 levels in mouse inner medullary collecting duct (IMCD3) cells. Dragon also inhibited E-cadherin expression but did not affect epithelial-to-mesenchymal transition induced by TGF-β in IMCD3 cells. Previous studies suggest that the three RGM members can function as ligands for the receptor neogenin. Interestingly, our present study demonstrates that the Dragon actions on apoptosis and E-cadherin expression in IMCD3 cells were mediated by the neogenin receptor but not through the BMP pathway. Dragon expression in the kidney was up-regulated by unilateral ureteral obstruction in mice. Compared with wild-type mice, heterozygous Dragon knock-out mice exhibited 45-66% reduction in Dragon mRNA expression, decreased epithelial apoptosis, and increased tubular E-cadherin expression and had attenuated tubular injury after unilateral ureteral obstruction. Our results suggest that Dragon may impair tubular epithelial integrity and induce epithelial apoptosis both in vitro and in vivo.
Collapse
Affiliation(s)
- Wenjing Liu
- From the Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Tian C, Liu J. Repulsive guidance molecules (RGMs) and neogenin in bone morphogenetic protein (BMP) signaling. Mol Reprod Dev 2013; 80:700-17. [PMID: 23740870 DOI: 10.1002/mrd.22199] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 05/28/2013] [Indexed: 02/06/2023]
Abstract
Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-beta (TGFβ) superfamily. BMPs mediate a highly conserved signal transduction cascade through the type-I and type-II serine/threonine kinase receptors and intracellular Smad proteins, which regulate multiple developmental and homeostatic processes. Mutations in this pathway can cause various diseases in humans, such as skeletal disorders, cardiovascular diseases, and various cancers. Multiple levels of regulation, including extracellular regulation, help to ensure proper spatiotemporal control of BMP signaling in the right cellular context. The family of repulsive guidance molecules (RGMs) and the type-I transmembrane protein neogenin, a paralog of DCC (Deleted in Colorectal Cancer), have been implicated in modulating the BMP pathway. In this review, we discuss the properties and functions of RGM proteins and neogenin, focusing on their roles in the modulation of BMP signal transduction.
Collapse
Affiliation(s)
- Chenxi Tian
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
| | | |
Collapse
|
18
|
Spatiotemporal expression of repulsive guidance molecules (RGMs) and their receptor neogenin in the mouse brain. PLoS One 2013; 8:e55828. [PMID: 23457482 PMCID: PMC3573027 DOI: 10.1371/journal.pone.0055828] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 01/02/2013] [Indexed: 02/07/2023] Open
Abstract
Neogenin has been implicated in a variety of developmental processes such as neurogenesis, neuronal differentiation, apoptosis, migration and axon guidance. Binding of repulsive guidance molecules (RGMs) to Neogenin inhibits axon outgrowth of different neuronal populations. This effect requires Neogenin to interact with co-receptors of the uncoordinated locomotion-5 (Unc5) family to activate downstream Rho signaling. Although previous studies have reported RGM, Neogenin, and/or Unc5 expression, a systematic comparison of RGM and Neogenin expression in the developing nervous system is lacking, especially at later developmental stages. Furthermore, information on RGM and Neogenin expression at the protein level is limited. To fill this void and to gain further insight into the role of RGM-Neogenin signaling during mouse neural development, we studied the expression of RGMa, RGMb, Neogenin and Unc5A-D using in situ hybridization, immunohistochemistry and RGMa section binding. Expression patterns in the primary olfactory system, cortex, hippocampus, habenula, and cerebellum were studied in more detail. Characteristic cell layer-specific expression patterns were detected for RGMa, RGMb, Neogenin and Unc5A-D. Furthermore, strong expression of RGMa, RGMb and Neogenin protein was found on several major axon tracts such as the primary olfactory projections, anterior commissure and fasciculus retroflexus. These data not only hint at a role for RGM-Neogenin signaling during the development of different neuronal systems, but also suggest that Neogenin partners with different Unc5 family members in different systems. Overall, the results presented here will serve as a framework for further dissection of the role of RGM-Neogenin signaling during neural development.
Collapse
|
19
|
Jorge EC, Ahmed MU, Bothe I, Coutinho LL, Dietrich S. RGMa and RGMb expression pattern during chicken development suggest unexpected roles for these repulsive guidance molecules in notochord formation, somitogenesis, and myogenesis. Dev Dyn 2012; 241:1886-900. [PMID: 23073896 DOI: 10.1002/dvdy.23889] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/01/2012] [Accepted: 10/01/2012] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Repulsive guidance molecules (RGM) are high-affinity ligands for the Netrin receptor Neogenin, and they are crucial for nervous system development including neural tube closure; neuronal and neural crest cell differentiation and axon guidance. Recent studies implicated RGM molecules in bone morphogenetic protein signaling, which regulates a variety of developmental processes. Moreover, a role for RGMc in iron metabolism has been established. This suggests that RGM molecules may play important roles in non-neural tissues. RESULTS To explore which tissues and processed may be regulated by RGM molecules, we systematically investigated the expression of RGMa and RGMb, the only RGM molecules currently known for avians, in the chicken embryo. CONCLUSIONS Our study suggests so far unknown roles of RGM molecules in notochord, somite and skeletal muscle development.
Collapse
Affiliation(s)
- Erika Cristina Jorge
- Universidade Federal de Minas Gerais-Departamento de Morfologia, Belo Horizonte, MG, Brazil.
| | | | | | | | | |
Collapse
|
20
|
The BMP coreceptor RGMb promotes while the endogenous BMP antagonist noggin reduces neurite outgrowth and peripheral nerve regeneration by modulating BMP signaling. J Neurosci 2012; 31:18391-400. [PMID: 22171041 DOI: 10.1523/jneurosci.4550-11.2011] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Repulsive guidance molecule b (RGMb) is a bone morphogenetic protein (BMP) coreceptor and sensitizer of BMP signaling, highly expressed in adult dorsal root ganglion (DRG) sensory neurons. We used a murine RGMb knock-out to gain insight into the physiological role of RGMb in the DRG, and address whether RGMb-mediated modulation of BMP signaling influences sensory axon regeneration. No evidence for altered development of the PNS and CNS was detected in RGMb(-/-) mice. However, both cultured neonatal whole DRG explants and dissociated DRG neurons from RGMb(-/-) mice exhibited significantly fewer and shorter neurites than those from wild-type littermates, a phenomenon that could be fully rescued by BMP-2. Moreover, Noggin, an endogenous BMP signaling antagonist, inhibited neurite outgrowth in wild-type DRG explants from naive as well as nerve injury-preconditioned mice. Noggin is downregulated in the DRG after nerve injury, and its expression is highly correlated and inversely associated with the known regeneration-associated genes, which are induced in the DRG by peripheral axonal injury. We show that diminished BMP signaling in vivo, achieved either through RGMb deletion or BMP inhibition with Noggin, retarded early axonal regeneration after sciatic nerve crush injury. Our data suggest a positive modulatory contribution of RGMb and BMP signaling to neurite extension in vitro and early axonal regrowth after nerve injury in vivo and a negative effect of Noggin.
Collapse
|
21
|
Novel roles of the chemorepellent axon guidance molecule RGMa in cell migration and adhesion. Mol Cell Biol 2012; 32:968-80. [PMID: 22215618 DOI: 10.1128/mcb.06128-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The repulsive guidance molecule A (RGMa) is a contact-mediated axon guidance molecule that has significant roles in central nervous system (CNS) development. Here we have examined whether RGMa has novel roles in cell migration and cell adhesion outside the nervous system. RGMa was found to stimulate cell migration from Xenopus animal cap explants in a neogenin-dependent and BMP-independent manner. RGMa also stimulated the adhesion of Xenopus animal cap cells, and this adhesion was dependent on neogenin and independent of calcium. To begin to functionally characterize the role of specific domains in RGMa, we assessed the migratory and adhesive activities of deletion mutants. RGMa lacking the partial von Willebrand factor type D (vWF) domain preferentially perturbed cell adhesion, while mutants lacking the RGD motif affected cell migration. We also revealed that manipulating the levels of RGMa in vivo caused major migration defects during Xenopus gastrulation. We have revealed here novel roles of RGMa in cell migration and adhesion and demonstrated that perturbations to the homeostasis of RGMa expression can severely disrupt major morphogenetic events. These results have implications for understanding the role of RGMa in both health and disease.
Collapse
|