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Xiao L, Qiao J, Huang Y, Tan B, Hong L, Li Z, Cai G, Wu Z, Zheng E, Wang S, Gu T. RASGRP1 targeted by H3K27me3 regulates myoblast proliferation and differentiation in mice and pigs. Acta Biochim Biophys Sin (Shanghai) 2024; 56:452-461. [PMID: 38419500 PMCID: PMC10984873 DOI: 10.3724/abbs.2024011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 11/14/2023] [Indexed: 03/02/2024] Open
Abstract
Skeletal muscle is not only the largest organ in the body that is responsible for locomotion and exercise but also crucial for maintaining the body's energy metabolism and endocrine secretion. The trimethylation of histone H3 lysine 27 (H3K27me3) is one of the most important histone modifications that participates in muscle development regulation by repressing the transcription of genes. Previous studies indicate that the RASGRP1 gene is regulated by H3K27me3 in embryonic muscle development in pigs, but its function and regulatory role in myogenesis are still unclear. In this study, we verify the crucial role of H3K27me3 in RASGRP1 regulation. The gain/loss function of RASGRP1 in myogenesis regulation is performed using mouse myoblast C2C12 cells and primarily isolated porcine skeletal muscle satellite cells (PSCs). The results of qPCR, western blot analysis, EdU staining, CCK-8 assay and immunofluorescence staining show that overexpression of RASGRP1 promotes cell proliferation and differentiation in both skeletal muscle cell models, while knockdown of RASGRP1 leads to the opposite results. These findings indicate that RASGRP1 plays an important regulatory role in myogenesis in both mice and pigs.
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Affiliation(s)
- Liyao Xiao
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
| | - Jiaxin Qiao
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
| | - Yiyang Huang
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
| | - Baohua Tan
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
| | - Linjun Hong
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
| | - Zicong Li
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresourcesGuangzhou510000China
- Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and TechnologyGuangzhou510000China
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular BreedingGuangzhou510000China
| | - Gengyuan Cai
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
- Guangdong Wens Breeding Swine Technology Co.Ltd.Yunfu527400China
| | - Zhenfang Wu
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresourcesGuangzhou510000China
- Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and TechnologyGuangzhou510000China
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular BreedingGuangzhou510000China
- Guangdong Wens Breeding Swine Technology Co.Ltd.Yunfu527400China
| | - Enqin Zheng
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
| | - Shanshan Wang
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
- College of Life ScienceHubei UniversityWuhan430000China
| | - Ting Gu
- National Engineering Research Center for Breeding Swine IndustryCollege of Animal ScienceSouth China Agricultural UniversityGuangzhou510000China
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Liu Y, Ouyang Y, Feng Z, Jiang Z, Ma J, Zhou X, Cai C, Han Y, Zeng S, Liu S, Shen H. RASGRP2 is a potential immune-related biomarker and regulates mitochondrial-dependent apoptosis in lung adenocarcinoma. Front Immunol 2023; 14:1100231. [PMID: 36817422 PMCID: PMC9936229 DOI: 10.3389/fimmu.2023.1100231] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 01/23/2023] [Indexed: 02/05/2023] Open
Abstract
Background Ras guanine nucleotide-releasing protein 2 (RASGRP2), one of the guanine nucleotide exchange factors (GEFs), has attracted much attention in recent years. However, the correlation between RASGRP2 and immune infiltration and malignant features in lung adenocarcinoma (LUAD) has rarely been mentioned. Methods The Limma package and the LASSO regression model were performed to screen for differentially expressed genes. Data from the TCGA and 5 GEO databases were used to explore the expression level of RASGRP2 in LUAD patients. A weighted co-expression network and LinkFinder module were established to find the related genes of RASGRP2. The ESTIMATE algorithm was used to analyze the correlation between RASGRP2 and immune infiltration in LUAD. Tumor-infiltrating immune cells were sorted and sequenced at the single-cell level to analyze differences in RASGRP2. Real-time PCR and immunohistochemistry were performed in the real-world cohort to verify the expression of RASGRP2 and its correlation with immune-related genes. Clone formation and EdU assays were used to verify the proliferation ability. The proportion of apoptotic cells was analyzed by flow cytometry. Observation of mitochondrial membrane potential (MMP) changes by fluorescence microscopy. Results Our results suggested that decreased RASGRP2 was associated with worse clinical parameters and prognosis in LUAD patients. And we constructed a FLI1-HSA-miR-1976-RASGRP2 transcriptional network to support the role of RASGRP2. Enrichment analysis revealed that RASGRP2 was involved in lymphocyte activation and leukocyte adhesion. RASGRP2 was found to be positively correlated with the infiltration of most immune cells, immunoregulators, and chemokines in a subsequent study. Meanwhile, the real-world cohort confirmed that the expression levels of PDCD1, CTLA4, CD40LG, CCL14, CXCR5, and CCR7 were higher in the high-RASGRP2 expression group. Cytological experiments proved that RASGRP2 inhibited cell proliferation in LUAD by regulating mitochondrial-dependent apoptosis. Conclusion RASGRP2 was a potential immune-related biomarker of LUAD. In addition, RASGRP2 was involved in the malignant progression of LUAD through the regulation of mitochondrial-dependent apoptosis.
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Affiliation(s)
- Yongting Liu
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yanhong Ouyang
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Emergency, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China
| | - Ziyang Feng
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhaohui Jiang
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jiayao Ma
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xin Zhou
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Changjing Cai
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ying Han
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shan Zeng
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shanshan Liu
- Department of Radiotherapy, Tianjin First Central Hospital, Tianjin, China
| | - Hong Shen
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
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Huang S, Wang J, Zhang L, Tian S, Wang Y, Shao X, Zhou S, Yu P. Ras guanine nucleotide-releasing protein-4 promotes renal inflammatory injury in type 2 diabetes mellitus. Metabolism 2022; 131:155177. [PMID: 35218794 DOI: 10.1016/j.metabol.2022.155177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/31/2022] [Accepted: 02/18/2022] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Ras guanine nucleotide-releasing protein-4 (RasGRP4) is an activator of Ras protein, which plays significant roles in both the inflammatory response and immune activation. This study determined the role of RasGRP4 in diabetic kidney disease (DKD) progression. METHODS CRISPR/Cas9 technology was used to establish RasGRP4 knockout (KO) mice. Diabetes was induced by a high-fat diet combined with five consecutive daily intraperitoneal injections of streptozotocin (60 mg/kg) in C57BL/6J wild-type (WT) mice and RasGRP4 KO mice. Hematoxylin and eosin, periodic acid-Schiff, and Masson's trichrome staining were used to observe the histology of pathological injury. Immunohistochemical staining was used to analyze inflammatory cell infiltration. Quantitative PCR and Western blotting were used to detect the expression of inflammatory mediators and the activation of signaling pathways in renal tissues. In vitro cell co-culture experiments were performed to explore the interactions between peripheral blood mononuclear cells (PBMCs) and glomerular endothelial cells (GEnCs). RESULTS RasGRP4 KO mice developed less severe diabetic kidney injury compared to WT mice, exhibiting lower proteinuria, reduced CD3+ T lymphocyte and F4/80+ macrophage infiltration, less inflammatory mediator expression including interleukin 6, tumor necrosis alpha, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, and lower expression levels of critical signal transduction molecules in the NLR family pyrin domain-containing 3 inflammasome and mitogen-activated protein kinase (MAPK)/nuclear factor kappa B (NF-κB) signaling pathways in the diabetic kidney. In vitro experiments showed that the adhesion function of PBMCs of RasGRP4 KO mice was reduced compared to that of WT mice. Moreover, the expression of adhesion molecules and critical signal transduction molecules in the NLRP3 inflammasome and MAPK/NF-κB signaling pathways in GEnCs was stimulated by the supernatant of PBMCs, which were derived from RasGRP4 KO mice treated with high glucose and were also significantly reduced compared to those derived from WT mice. CONCLUSION RasGRP4 promotes the inflammatory injury mediated by PBMCs in diabetes, probably by regulating the interaction between PBMCs and GEnCs and further activating the NLRP3 inflammasome and MAPK/NF-κB signaling pathways.
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Affiliation(s)
- Shuai Huang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Junmei Wang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Li Zhang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Shasha Tian
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Yao Wang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Xian Shao
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Saijun Zhou
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Pei Yu
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China.
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Benoit A, Bou-Petit E, Chou H, Lu M, Guilbert C, Luo VM, Assouline S, Morin RD, Dmitrienko S, Estrada-Tejedor R, Johnson NA, Mann KK. Mutated RAS-associating proteins and ERK activation in relapse/refractory diffuse large B cell lymphoma. Sci Rep 2022; 12:779. [PMID: 35039569 PMCID: PMC8764096 DOI: 10.1038/s41598-021-04736-0] [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: 07/14/2021] [Accepted: 12/06/2021] [Indexed: 11/16/2022] Open
Abstract
Diffuse large B cell lymphoma (DLBCL) is successfully treated with combination immuno-chemotherapy, but relapse with resistant disease occurs in ~ 40% of patients. However, little is known regarding relapsed/refractory DLBCL (rrDLBCL) genetics and alternative therapies. Based on findings from other tumors, we hypothesized that RAS-MEK-ERK signaling would be upregulated in resistant tumors, potentially correlating with mutations in RAS, RAF, or associated proteins. We analyzed mutations and phospho-ERK levels in tumor samples from rrDLBCL patients. Unlike other tumor types, rrDLBCL is not mutated in any Ras or Raf family members, despite having increased expression of p-ERK. In paired biopsies comparing diagnostic and relapsed specimens, 33% of tumors gained p-ERK expression, suggesting a role in promoting survival. We did find mutations in several Ras-associating proteins, including GEFs, GAPs, and downstream effectors that could account for increased ERK activation. We further investigated mutations in one such protein, RASGRP4. In silico modeling indicated an increased interaction between H-Ras and mutant RASGRP4. In cell lines, mutant RASGRP4 increased basal p-ERK expression and lead to a growth advantage in colony forming assays when challenged with doxorubicin. Relapsed/refractory DLBCL is often associated with increased survival signals downstream of ERK, potentially corresponding with mutations in protein controlling RAS/MEK/ERK signaling.
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Affiliation(s)
- Alexandre Benoit
- Lady Davis Institute, Jewish General Hospital, 3755 Côte Sainte-Catherine Road, Montreal, QC, H3T 1E2, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Elisabeth Bou-Petit
- Grup de Química Farmacèutica, IQS School of Engineering, Universitat Ramon Llull, Barcelona, Spain
| | - Hsiang Chou
- Lady Davis Institute, Jewish General Hospital, 3755 Côte Sainte-Catherine Road, Montreal, QC, H3T 1E2, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Melissa Lu
- Université de Montréal-Faculté de Médecine, Montreal, Canada
| | - Cynthia Guilbert
- Lady Davis Institute, Jewish General Hospital, 3755 Côte Sainte-Catherine Road, Montreal, QC, H3T 1E2, Canada
| | - Vincent Mingyi Luo
- Lady Davis Institute, Jewish General Hospital, 3755 Côte Sainte-Catherine Road, Montreal, QC, H3T 1E2, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Sarit Assouline
- Lady Davis Institute, Jewish General Hospital, 3755 Côte Sainte-Catherine Road, Montreal, QC, H3T 1E2, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC, Canada.,Gerald Bronfman Department of Oncology, McGill University, Montreal, QC, Canada
| | - Ryan D Morin
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Svetlana Dmitrienko
- Division of Pathology, McGill University Health Centre, Montreal, QC, Canada
| | - Roger Estrada-Tejedor
- Grup de Química Farmacèutica, IQS School of Engineering, Universitat Ramon Llull, Barcelona, Spain
| | - Nathalie A Johnson
- Lady Davis Institute, Jewish General Hospital, 3755 Côte Sainte-Catherine Road, Montreal, QC, H3T 1E2, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC, Canada.,Gerald Bronfman Department of Oncology, McGill University, Montreal, QC, Canada
| | - Koren K Mann
- Lady Davis Institute, Jewish General Hospital, 3755 Côte Sainte-Catherine Road, Montreal, QC, H3T 1E2, Canada. .,Division of Experimental Medicine, McGill University, Montreal, QC, Canada. .,Gerald Bronfman Department of Oncology, McGill University, Montreal, QC, Canada.
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Canault M, Alessi MC. RasGRP2 Structure, Function and Genetic Variants in Platelet Pathophysiology. Int J Mol Sci 2020; 21:E1075. [PMID: 32041177 PMCID: PMC7037602 DOI: 10.3390/ijms21031075] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 12/18/2022] Open
Abstract
RasGRP2 is calcium and diacylglycerol-regulated guanine nucleotide exchange factor I that activates Rap1, which is an essential signaling-knot in "inside-out" αIIbβ3 integrin activation in platelets. Inherited platelet function disorder caused by variants of RASGRP2 represents a new congenital bleeding disorder referred to as platelet-type bleeding disorder-18 (BDPLT18). We review here the structure of RasGRP2 and its functions in the pathophysiology of platelets and of the other cellular types that express it. We will also examine the different pathogenic variants reported so far as well as strategies for the diagnosis and management of patients with BDPLT18.
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Affiliation(s)
- Matthias Canault
- Aix Marseille University, INSERM, INRAE, C2VN, 13005 Marseille, France
| | - Marie-Christine Alessi
- Aix Marseille University, INSERM, INRAE, C2VN, 13005 Marseille, France
- Hematology laboratory, APHM, CHU Timone, 13005 Marseille, France
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Zhu L, Xia C, Wu L, Zhang Y, Liu J, Chen Y, Liu J, Xiao Y, Nie K, Huang L, Qu N, Yu H. The critical role of RasGRP4 in the growth of diffuse large B cell lymphoma. Cell Commun Signal 2019; 17:92. [PMID: 31409422 PMCID: PMC6693169 DOI: 10.1186/s12964-019-0415-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 08/06/2019] [Indexed: 12/22/2022] Open
Abstract
Background This study aimed to confirm that blocking RasGRP4 can effectively slow down the growth of DLBCL both in vitro and in vivo and ascertain the role of RasGRP4 in the prognosis of DLBCL clinically. Methods RasGRP4 expression levels were examined in benign tissues and lymphomas. In order to verify somatic mutation in RasGRP4 gene, cDNA sequencing was performed in DLBCL patients. RasGRP4-dependent cell proliferation, mitochondrial membrane potential, oxidative stress levels and signaling pathway changes were measured by knockdown of RasGRP4. Tumor growth was monitored in xenografted lymphoma model. Clinical data were collected to confirm the role of RasGRP4 in DLBCL. Results RasGRP4 expression was significantly elevated in DLBCL while no somatic mutations were detected of this gene in DLBCL patients. Decreased RasGRP4 significantly inhibited cell proliferation by simultaneously reducing mitosis and promoting apoptosis and increased the oxidative stress levels. Mechanistically, reduced expression of RasGRP4 decreased ERK while increased JNK expression in SUDHL-4 cells. Knockdown of RasGRP4 also significantly inhibited tumor formation in vivo. Furthermore, RasGRP4 expression levels were significantly higher in patients with larger DLBCL lesions (P = 0.0004), high-risk international prognostic index score groups (P = 0.0042), and its expression was positively correlated with maximum standardized uptake value in DLBCL (P = 0.0004). Conclusions These findings indicate the oncogenic role of RasGRP4 in DLBCL, suggesting it as a prognostic biomarker and potential therapeutic target in DLBCL. Electronic supplementary material The online version of this article (10.1186/s12964-019-0415-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lin Zhu
- Shanghai Chest Hospital Affiliated to Shanghai Jiao Tong University, No. 241 West Huaihai Road, Shanghai, 200030, China
| | - Chunyan Xia
- Shanghai Changzheng Hospital Affiliated to the Second Military Medical University, Shanghai, China
| | - Lin Wu
- Shanghai General Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China
| | - Yuxuan Zhang
- School of Pharmacy, Queen's University Belfast Medical Biology Centre, Belfast, UK
| | - Junling Liu
- School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yinan Chen
- Shanghai Chest Hospital Affiliated to Shanghai Jiao Tong University, No. 241 West Huaihai Road, Shanghai, 200030, China
| | - Jing Liu
- Shanghai Changzheng Hospital Affiliated to the Second Military Medical University, Shanghai, China
| | - Yongxin Xiao
- Shanghai Changzheng Hospital Affiliated to the Second Military Medical University, Shanghai, China
| | - Kai Nie
- Shanghai Changzheng Hospital Affiliated to the Second Military Medical University, Shanghai, China
| | - Liyu Huang
- Shanghai Changzheng Hospital Affiliated to the Second Military Medical University, Shanghai, China
| | - Ning Qu
- Fudan University Shanghai Cancer Center, Shanghai, China
| | - Hong Yu
- Shanghai Chest Hospital Affiliated to Shanghai Jiao Tong University, No. 241 West Huaihai Road, Shanghai, 200030, China.
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Benedé S, Berin MC. Mast cell heterogeneity underlies different manifestations of food allergy in mice. PLoS One 2018; 13:e0190453. [PMID: 29370173 PMCID: PMC5784907 DOI: 10.1371/journal.pone.0190453] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/14/2017] [Indexed: 12/31/2022] Open
Abstract
Food can trigger a diverse array of symptoms in food allergic individuals from isolated local symptoms affecting skin or gut to multi-system severe reactions (systemic anaphylaxis). Although we know that gastrointestinal and systemic manifestations of food allergy are mediated by tissue mast cells (MCs), it is not clear why allergen exposure by the oral route can result in such distinct clinical manifestations. Our aim was to assess the contribution of mast cell subsets to different manifestations of food allergy. We used two common models of IgE-mediated food allergy, one resulting in systemic anaphylaxis and the other resulting in acute gastrointestinal symptoms, to study the immune basis of allergic reactions. We used responders and non-responders in each model system, as well as naïve controls to identify the association of mast cell activation with clinical reactivity rather than sensitization. Systemic anaphylaxis was uniquely associated with activation of connective tissue mast cells (identified by release of mouse mast cell protease (MMCP) -7 into the serum) and release of histamine, while activation of mucosal mast cells (identified by release of MMCP-1 in the serum) did not correlate with symptoms. Gastrointestinal manifestations of food allergy were associated with an increase of MMCP-1-expressing mast cells in the intestine, and evidence of both mucosal and connective tissue mast cell activation. The data presented in this paper demonstrates that mast cell heterogeneity is an important contributor to manifestations of food allergy, and identifies the connective tissue mast cell subset as key in the development of severe systemic anaphylaxis.
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Affiliation(s)
- Sara Benedé
- Jaffe Food Allergy Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - M. Cecilia Berin
- Jaffe Food Allergy Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
- * E-mail:
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Eyring KR, Pedersen BS, Maclean KN, Stabler SP, Yang IV, Schwartz DA. Methylene-tetrahydrofolate reductase contributes to allergic airway disease. PLoS One 2018; 13:e0190916. [PMID: 29329322 PMCID: PMC5766142 DOI: 10.1371/journal.pone.0190916] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 12/22/2017] [Indexed: 12/01/2022] Open
Abstract
Rationale Environmental exposures strongly influence the development and progression of asthma. We have previously demonstrated that mice exposed to a diet enriched with methyl donors during vulnerable periods of fetal development can enhance the heritable risk of allergic airway disease through epigenetic changes. There is conflicting evidence on the role of folate (one of the primary methyl donors) in modifying allergic airway disease. Objectives We hypothesized that blocking folate metabolism through the loss of methylene-tetrahydrofolate reductase (Mthfr) activity would reduce the allergic airway disease phenotype through epigenetic mechanisms. Methods Allergic airway disease was induced in C57BL/6 and C57BL/6Mthfr-/- mice through house dust mite (HDM) exposure. Airway inflammation and airway hyperresponsiveness (AHR) were measured between the two groups. Gene expression and methylation profiles were generated for whole lung tissue. Disease and molecular outcomes were evaluated in C57BL/6 and C57BL/6Mthfr-/- mice supplemented with betaine. Measurements and main results Loss of Mthfr alters single carbon metabolite levels in the lung and serum including elevated homocysteine and cystathionine and reduced methionine. HDM-treated C57BL/6Mthfr-/- mice demonstrated significantly less airway hyperreactivity (AHR) compared to HDM-treated C57BL/6 mice. Furthermore, HDM-treated C57BL/6Mthfr-/- mice compared to HDM-treated C57BL/6 mice have reduced whole lung lavage (WLL) cellularity, eosinophilia, and Il-4/Il-5 cytokine concentrations. Betaine supplementation reversed parts of the HDM-induced allergic airway disease that are modified by Mthfr loss. 737 genes are differentially expressed and 146 regions are differentially methylated in lung tissue from HDM-treated C57BL/6Mthfr-/- mice and HDM-treated C57BL/6 mice. Additionally, analysis of methylation/expression relationships identified 503 significant correlations. Conclusion Collectively, these findings indicate that the loss of folate as a methyl donor is a modifier of allergic airway disease, and that epigenetic and expression changes correlate with this modification. Further investigation into the mechanisms that drive this observation is warranted.
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Affiliation(s)
- Kenneth R. Eyring
- Department of Medicine, School of Medicine, University of Colorado, Aurora, CO, United States of America
| | - Brent S. Pedersen
- Department of Medicine, School of Medicine, University of Colorado, Aurora, CO, United States of America
| | - Kenneth N. Maclean
- Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, United States of America
| | - Sally P. Stabler
- Department of Medicine, School of Medicine, University of Colorado, Aurora, CO, United States of America
| | - Ivana V. Yang
- Department of Medicine, School of Medicine, University of Colorado, Aurora, CO, United States of America
| | - David A. Schwartz
- Department of Medicine, School of Medicine, University of Colorado, Aurora, CO, United States of America
- Department of Immunology, School of Medicine, University of Colorado, Aurora, CO, United States of America
- * E-mail:
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9
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Shah B, Püschel AW. Regulation of Rap GTPases in mammalian neurons. Biol Chem 2017; 397:1055-69. [PMID: 27186679 DOI: 10.1515/hsz-2016-0165] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/06/2016] [Indexed: 12/15/2022]
Abstract
Small GTPases are central regulators of many cellular processes. The highly conserved Rap GTPases perform essential functions in the mammalian nervous system during development and in mature neurons. During neocortical development, Rap1 is required to regulate cadherin- and integrin-mediated adhesion. In the adult nervous system Rap1 and Rap2 regulate the maturation and plasticity of dendritic spine and synapses. Although genetic studies have revealed important roles of Rap GTPases in neurons, their regulation by guanine nucleotide exchange factors (GEFs) that activate them and GTPase activating proteins (GAPs) that inactivate them by stimulating their intrinsic GTPase activity is just beginning to be explored in vivo. Here we review how GEFs and GAPs regulate Rap GTPases in the nervous system with a focus on their in vivo function.
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Golec DP, Henao Caviedes LM, Baldwin TA. RasGRP1 and RasGRP3 Are Required for Efficient Generation of Early Thymic Progenitors. THE JOURNAL OF IMMUNOLOGY 2016; 197:1743-53. [PMID: 27465532 DOI: 10.4049/jimmunol.1502107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 06/28/2016] [Indexed: 11/19/2022]
Abstract
T cell development is dependent on the migration of progenitor cells from the bone marrow to the thymus. Upon reaching the thymus, progenitors undergo a complex developmental program that requires inputs from various highly conserved signaling pathways including the Notch and Wnt pathways. To date, Ras signaling has not been implicated in the very earliest stages of T cell differentiation, but members of a family of Ras activators called RasGRPs have been shown to be involved at multiple stages of T cell development. We examined early T cell development in mice lacking RasGRP1, RasGRP3, and RasGRPs 1 and 3. We report that RasGRP1- and RasGRP3-deficient thymi show significantly reduced numbers of early thymic progenitors (ETPs) relative to wild type thymi. Furthermore, RasGRP1/3 double-deficient thymi show significant reductions in ETP numbers compared with either RasGRP1 or RasGRP3 single-deficient thymi, suggesting that both RasGRP1 and RasGRP3 regulate the generation of ETPs. In addition, competitive bone marrow chimera experiments reveal that RasGRP1/3 double-deficient progenitors intrinsically generate ETPs less efficiently than wild type progenitors. Finally, RasGRP1/3-deficient progenitors show impaired migration toward the CCR9 ligand, CCL25, suggesting that RasGRP1 and RasGRP3 may regulate progenitor entry into the thymus through a CCR9-dependent mechanism. These data demonstrate that, in addition to Notch and Wnt, the highly conserved Ras pathway is critical for the earliest stages of T cell development and further highlight the importance of Ras signaling during thymocyte maturation.
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Affiliation(s)
- Dominic P Golec
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Laura M Henao Caviedes
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Troy A Baldwin
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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11
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Zhou S, Tanaka K, O’Keeffe M, Qi M, El-Assaad F, Weaver JC, Chen G, Weatherall C, Wang Y, Giannakopoulos B, Chen L, Yu D, Hamilton MJ, Wensing LA, Stevens RL, Krilis SA. CD117+ Dendritic and Mast Cells Are Dependent on RasGRP4 to Function as Accessory Cells for Optimal Natural Killer Cell-Mediated Responses to Lipopolysaccharide. PLoS One 2016; 11:e0151638. [PMID: 26982501 PMCID: PMC4794117 DOI: 10.1371/journal.pone.0151638] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 03/02/2016] [Indexed: 11/25/2022] Open
Abstract
Ras guanine nucleotide-releasing protein-4 (RasGRP4) is an evolutionarily conserved calcium-regulated, guanine nucleotide exchange factor and diacylglycerol/phorbol ester receptor. While an important intracellular signaling protein for CD117+ mast cells (MCs), its roles in other immune cells is less clear. In this study, we identified a subset of in vivo-differentiated splenic CD117+ dendritic cells (DCs) in wild-type (WT) C57BL/6 mice that unexpectedly contained RasGRP4 mRNA and protein. In regard to the biologic significance of these data to innate immunity, LPS-treated splenic CD117+ DCs from WT mice induced natural killer (NK) cells to produce much more interferon-γ (IFN-γ) than comparable DCs from RasGRP4-null mice. The ability of LPS-responsive MCs to cause NK cells to increase their expression of IFN-γ was also dependent on this intracellular signaling protein. The discovery that RasGRP4 is required for CD117+ MCs and DCs to optimally induce acute NK cell-dependent immune responses to LPS helps explain why this signaling protein has been conserved in evolution.
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Affiliation(s)
- Saijun Zhou
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Laboratory of Hormones and Development (Ministry of Health), Metabolic Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, TJ, China
| | - Kumiko Tanaka
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Meredith O’Keeffe
- Dendritic Cell Research Laboratory, Immunity Vaccines and Immunisation, Burnet Institute, Prahran, Melbourne, Victoria, Australia
| | - Miao Qi
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Fatima El-Assaad
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - James C. Weaver
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Department of Cardiology, St. George Hospital, Sydney, New South Wales, Australia
| | - Gang Chen
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Christopher Weatherall
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Ying Wang
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Bill Giannakopoulos
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Liming Chen
- Laboratory of Hormones and Development (Ministry of Health), Metabolic Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, TJ, China
| | - DeMint Yu
- Laboratory of Hormones and Development (Ministry of Health), Metabolic Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, TJ, China
| | - Matthew J. Hamilton
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia
- Division of Gastroenterology, Brigham and Women’s Hospital, Boston, MA, United States of America
| | - Lislaine A. Wensing
- Departament of Immunology, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil
| | - Richard L. Stevens
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia
| | - Steven A. Krilis
- Department of Infectious Diseases, Immunology, and Sexual Health, St. George Hospital, and the St. George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
- * E-mail:
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12
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Daley SR, Coakley KM, Hu DY, Randall KL, Jenne CN, Limnander A, Myers DR, Polakos NK, Enders A, Roots C, Balakishnan B, Miosge LA, Sjollema G, Bertram EM, Field MA, Shao Y, Andrews TD, Whittle B, Barnes SW, Walker JR, Cyster JG, Goodnow CC, Roose JP. Rasgrp1 mutation increases naive T-cell CD44 expression and drives mTOR-dependent accumulation of Helios⁺ T cells and autoantibodies. eLife 2013; 2:e01020. [PMID: 24336796 PMCID: PMC3858598 DOI: 10.7554/elife.01020] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Missense variants are a major source of human genetic variation. Here we analyze a new mouse missense variant, Rasgrp1Anaef, with an ENU-mutated EF hand in the Rasgrp1 Ras guanine nucleotide exchange factor. Rasgrp1Anaef mice exhibit anti-nuclear autoantibodies and gradually accumulate a CD44hi Helios+ PD-1+ CD4+ T cell population that is dependent on B cells. Despite reduced Rasgrp1-Ras-ERK activation in vitro, thymocyte selection in Rasgrp1Anaef is mostly normal in vivo, although CD44 is overexpressed on naïve thymocytes and T cells in a T-cell-autonomous manner. We identify CD44 expression as a sensitive reporter of tonic mTOR-S6 kinase signaling through a novel mouse strain, chino, with a reduction-of-function mutation in Mtor. Elevated tonic mTOR-S6 signaling occurs in Rasgrp1Anaef naïve CD4+ T cells. CD44 expression, CD4+ T cell subset ratios and serum autoantibodies all returned to normal in Rasgrp1AnaefMtorchino double-mutant mice, demonstrating that increased mTOR activity is essential for the Rasgrp1Anaef T cell dysregulation. DOI:http://dx.doi.org/10.7554/eLife.01020.001 Our DNA contains more than three billion nucleotides. Each of these nucleotides can be an A, C, G or T, and groups of three neighboring nucleotides within our DNA are used to represent the 20 amino acids that are used to make proteins. This means that changing just one nucleotide can cause one amino acid to be replaced by a different amino acid in the protein encoded by that stretch of DNA: AAA and AAG code for the amino acid lysine, for example, but AAC and AAT code for asparagine. Known as missense gene variants, these changes can also increase or decrease the expression of the gene. Every person has thousands of missense gene variants, including about 12,000 inherited from their parents. Sometimes these variants have no consequence, but they can be harmful if replacing the correct amino acid with a different amino acid prevents the protein from performing an important task. In particular, missense gene variants in genes that encode immune system proteins are likely to play a role in diseases of the immune system. For example, variants near a gene called Rasgrp1 have been linked to two autoimmune diseases – type 1 diabetes and Graves’ disease—in which the immune system mistakenly attacks the body’s own cells and tissues. Now Daley et al. have shed new light on the mechanism by which a missense gene variant in Rasgrp1 can cause autoimmune diseases. Mice with this mutation show signs of autoimmune disease, but their T cells—white blood cells that have a central role in the immune system – develop normally despite this mutation. Instead, Daley et al. found that a specific type of T cell, called T helper cells, accumulated in large numbers in the mutant mice and stimulated cells of a third type—immune cells called B cells—to produce autoantibodies. The production of autoantibodies is a common feature of autoimmune diseases. Daley et al. traced the origins of the T helper cells to excessive activity on a signaling pathway that involves a protein called mTOR, and went on to show that treatment with the drug rapamycin counteracted the accumulation of the T helper cells and reduced the level of autoimmune activity. In addition to exemplifying how changing just one amino acid change can have a profound effect, the work of Daley et al. is an attractive model for exploring how missense gene variants in people can contribute to autoimmune diseases. DOI:http://dx.doi.org/10.7554/eLife.01020.002
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Affiliation(s)
- Stephen R Daley
- Department of Immunology, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
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13
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Kortum RL, Balagopalan L, Alexander CP, Garcia J, Pinski JM, Merrill RK, Nguyen PH, Li W, Agarwal I, Akpan IO, Sommers CL, Samelson LE. The ability of Sos1 to oligomerize the adaptor protein LAT is separable from its guanine nucleotide exchange activity in vivo. Sci Signal 2013; 6:ra99. [PMID: 24222714 DOI: 10.1126/scisignal.2004494] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The activation of the small guanosine triphosphatase Ras by the guanine nucleotide exchange factor (GEF) Sos1 (Son of Sevenless 1) is a central feature of many receptor-stimulated signaling pathways. In developing T cells (thymocytes), Sos1-dependent activation of extracellular signal-regulated kinase (ERK) is required to stimulate cellular proliferation and differentiation. We showed that in addition to its GEF activity, Sos1 acted as a scaffold to nucleate oligomerization of the T cell adaptor protein LAT (linker for activation of T cells) in vivo. The scaffold function of Sos1 depended on its ability to bind to the adaptor protein Grb2. Furthermore, the GEF activity of Sos1 and the Sos1-dependent oligomerization of LAT were separable functions in vivo. Whereas the GEF activity of Sos1 was required for optimal ERK phosphorylation in response to T cell receptor (TCR) stimulation, the Sos1-dependent oligomerization of LAT was required for maximal TCR-dependent phosphorylation and activation of phospholipase C-γ1 and Ca(2+) signaling. Finally, both of these Sos1 functions were required for early thymocyte proliferation. Whereas transgenic restoration of either the GEF activity or the LAT oligomerization functions of Sos1 alone failed to rescue thymocyte development in Sos1-deficient mice, simultaneous reconstitution of these two signals in the same cell restored normal T cell development. This ability of Sos1 to act both as a RasGEF and as a scaffold to nucleate Grb2-dependent adaptor oligomerization may also occur in other Grb2-dependent pathways, such as those activated by growth factor receptors.
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Affiliation(s)
- Robert L Kortum
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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14
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Ksionda O, Limnander A, Roose JP. RasGRP Ras guanine nucleotide exchange factors in cancer. FRONTIERS IN BIOLOGY 2013; 8:508-532. [PMID: 24744772 PMCID: PMC3987922 DOI: 10.1007/s11515-013-1276-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
RasGRP proteins are activators of Ras and other related small GTPases by the virtue of functioning as guanine nucleotide exchange factors (GEFs). In vertebrates, four RasGRP family members have been described. RasGRP-1 through -4 share many structural domains but there are also subtle differences between each of the different family members. Whereas SOS RasGEFs are ubiquitously expressed, RasGRP proteins are expressed in distinct patterns, such as in different cells of the hematopoietic system and in the brain. Most studies have concentrated on the role of RasGRP proteins in the development and function of immune cell types because of the predominant RasGRP expression profiles in these cells and the immune phenotypes of mice deficient for Rasgrp genes. However, more recent studies demonstrate that RasGRPs also play an important role in tumorigenesis. Examples are skin- and hematological-cancers but also solid malignancies such as melanoma or prostate cancer. These novel studies bring up many new and unanswered questions related to the molecular mechanism of RasGRP-driven oncogenesis, such as new receptor systems that RasGRP appears to respond to as well as regulatory mechanism for RasGRP expression that appear to be perturbed in these cancers. Here we will review some of the known aspects of RasGRP biology in lymphocytes and will discuss the exciting new notion that RasGRP Ras exchange factors play a role in oncogenesis downstream of various growth factor receptors.
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Affiliation(s)
- Olga Ksionda
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Andre Limnander
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jeroen P. Roose
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
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15
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Jun JE, Rubio I, Roose JP. Regulation of ras exchange factors and cellular localization of ras activation by lipid messengers in T cells. Front Immunol 2013; 4:239. [PMID: 24027568 PMCID: PMC3762125 DOI: 10.3389/fimmu.2013.00239] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 08/02/2013] [Indexed: 11/17/2022] Open
Abstract
The Ras-MAPK signaling pathway is highly conserved throughout evolution and is activated downstream of a wide range of receptor stimuli. Ras guanine nucleotide exchange factors (RasGEFs) catalyze GTP loading of Ras and play a pivotal role in regulating receptor-ligand induced Ras activity. In T cells, three families of functionally important RasGEFs are expressed: RasGRF, RasGRP, and Son of Sevenless (SOS)-family GEFs. Early on it was recognized that Ras activation is critical for T cell development and that the RasGEFs play an important role herein. More recent work has revealed that nuances in Ras activation appear to significantly impact T cell development and selection. These nuances include distinct biochemical patterns of analog versus digital Ras activation, differences in cellular localization of Ras activation, and intricate interplays between the RasGEFs during distinct T cell developmental stages as revealed by various new mouse models. In many instances, the exact nature of these nuances in Ras activation or how these may result from fine-tuning of the RasGEFs is not understood. One large group of biomolecules critically involved in the control of RasGEFs functions are lipid second messengers. Multiple, yet distinct lipid products are generated following T cell receptor (TCR) stimulation and bind to different domains in the RasGRP and SOS RasGEFs to facilitate the activation of the membrane-anchored Ras GTPases. In this review we highlight how different lipid-based elements are generated by various enzymes downstream of the TCR and other receptors and how these dynamic and interrelated lipid products may fine-tune Ras activation by RasGEFs in developing T cells.
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Affiliation(s)
- Jesse E Jun
- Department of Anatomy, University of California San Francisco , San Francisco, CA , USA
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16
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Song X, Lopez-Campistrous A, Sun L, Dower NA, Kedei N, Yang J, Kelsey JS, Lewin NE, Esch TE, Blumberg PM, Stone JC. RasGRPs are targets of the anti-cancer agent ingenol-3-angelate. PLoS One 2013; 8:e72331. [PMID: 23991094 PMCID: PMC3749120 DOI: 10.1371/journal.pone.0072331] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 07/08/2013] [Indexed: 11/26/2022] Open
Abstract
Ingenol-3–angelate (I3A) is a non-tumor promoting phorbol ester-like compound identified in the sap of Euphoria peplus. Similar to tumor promoting phorbol esters, I3A is a diacylglycerol (DAG) analogue that binds with high affinity to the C1 domains of PKCs, recruits PKCs to cellular membranes and promotes enzyme activation. Numerous anti-cancer activities have been attributed to I3A and ascribed to I3A’s effects on PKCs. We show here that I3A also binds to and activates members of the RasGRP family of Ras activators leading to robust elevation of Ras-GTP and engagement of the Raf-Mek-Erk kinase cascade. In response to I3A, recombinant proteins consisting of GFP fused separately to full-length RasGRP1 and RasGRP3 were rapidly recruited to cell membranes, consistent with direct binding of the compound to RasGRP’s C1 domain. In the case of RasGRP3, IA3 treatment led to positive regulatory phosphorylation on T133 and activation of the candidate regulatory kinase PKCδ. I3A treatment of select B non-Hodgkin’s lymphoma cell lines resulted in quantitative and qualitative changes in Bcl-2 family member proteins and induction of apoptosis, as previously demonstrated with the DAG analogue bryostatin 1 and its synthetic analogue pico. Our results offer further insights into the anticancer properties of I3A, support the idea that RasGRPs represent potential cancer therapeutic targets along with PKC, and expand the known range of ligands for RasGRP regulation.
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Affiliation(s)
- Xiaohua Song
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | | | - Lucy Sun
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Nancy A. Dower
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Noemi Kedei
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jing Yang
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jessica S. Kelsey
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nancy E. Lewin
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tim E. Esch
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Peter M. Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - James C. Stone
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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17
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Iwig JS, Vercoulen Y, Das R, Barros T, Limnander A, Che Y, Pelton JG, Wemmer DE, Roose JP, Kuriyan J. Structural analysis of autoinhibition in the Ras-specific exchange factor RasGRP1. eLife 2013; 2:e00813. [PMID: 23908768 PMCID: PMC3728621 DOI: 10.7554/elife.00813] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 06/18/2013] [Indexed: 11/13/2022] Open
Abstract
RasGRP1 and SOS are Ras-specific nucleotide exchange factors that have distinct roles in lymphocyte development. RasGRP1 is important in some cancers and autoimmune diseases but, in contrast to SOS, its regulatory mechanisms are poorly understood. Activating signals lead to the membrane recruitment of RasGRP1 and Ras engagement, but it is unclear how interactions between RasGRP1 and Ras are suppressed in the absence of such signals. We present a crystal structure of a fragment of RasGRP1 in which the Ras-binding site is blocked by an interdomain linker and the membrane-interaction surface of RasGRP1 is hidden within a dimerization interface that may be stabilized by the C-terminal oligomerization domain. NMR data demonstrate that calcium binding to the regulatory module generates substantial conformational changes that are incompatible with the inactive assembly. These features allow RasGRP1 to be maintained in an inactive state that is poised for activation by calcium and membrane-localization signals. DOI:http://dx.doi.org/10.7554/eLife.00813.001 Individual cells within the human body must grow, divide or specialize to perform the tasks required of them. The fates of these cells are often directed by proteins in the Ras family, which detect signals from elsewhere in the body and orchestrate responses within each cell. The activities of these proteins must be tightly controlled, because cancers and developmental diseases can result if Ras proteins are not properly regulated. Binding to the small molecule GTP activates Ras and causes conformational changes that allow it to interact with other proteins in various signaling pathways in the cell. GTP is loaded into Ras by proteins called nucleotide exchange factors, which can replace ‘used’ nucleotides with ‘fresh’ ones to activate Ras. These nucleotide exchange factors are also tightly regulated. For example, the genes for many exchange factors are only switched on after particular signals are received, which can restrict their presence to defined times and locations (e.g., cells or tissues). Also, when activating signals are absent, nucleotide exchange factors commonly reside in the cytoplasm, whereas the Ras proteins remain bound to lipid membranes inside the cell. RasGRP1 is a nucleotide exchange factor that controls the development of immune cells, and leukemia and lupus can result if it is not regulated correctly. However, many questions about RasGRP1 remain unanswered, including how it is able to remain inactive, and how it is activated by various different signals. Iwig et al. have now revealed the mechanisms through which RasGRP1 suppresses Ras signaling in immune cells by solving the structures of two fragments of RasGRP1 and then using a combination of structural, biochemical and cell-based methods to explore how it is activated. These analyses revealed that inactive RasGRP1 adopts a conformation in which one of its regulatory elements blocks access to the Ras binding site. Surprisingly, RasGRP1 can form dimers; this hides the portions of the protein that associate with the membrane and thereby keeps RasGRP1 away from Ras. Iwig et al. also found that two signals, calcium ions and a lipid called diacylglycerol, overcome these inhibitory mechanisms by changing the conformation of RasGRP1 and recruiting it to the membrane. These studies provide a framework for understanding how disease-associated mutations in RasGRP1 bypass the regulatory mechanisms that insure proper immune cell development, and will be critical for developing therapeutic agents that inhibit RasGRP1 activity. DOI:http://dx.doi.org/10.7554/eLife.00813.002
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Affiliation(s)
- Jeffrey S Iwig
- Department of Molecular and Cell Biology , University of California, Berkeley , Berkeley , United States ; California Institute for Quantitative Biosciences , University of California, Berkeley , Berkeley , United States
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18
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Kortum RL, Rouquette-Jazdanian AK, Samelson LE. Ras and extracellular signal-regulated kinase signaling in thymocytes and T cells. Trends Immunol 2013; 34:259-68. [PMID: 23506953 DOI: 10.1016/j.it.2013.02.004] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/04/2013] [Accepted: 02/12/2013] [Indexed: 12/22/2022]
Abstract
Extracellular signal-regulated kinase (ERK) activation is important for both thymocyte development and T cell function. Classically, signal transduction from the T cell antigen receptor (TCR) to ERK is thought to be regulated by signaling from Ras guanine nucleotide exchange factors (GEFs), through the small G protein Ras, to the three-tiered Raf-MAPK/ERK kinase (MEK)-ERK kinase cascade. Developing and mature T cells express four members of two RasGEF families, RasGRP1, RasGRP4, son of sevenless 1 (Sos1), and Sos2, and several models describing combined signaling from these RasGEFs have been proposed. However, recent studies suggest that existing models need revision to include both distinct and overlapping roles of multiple RasGEFs during thymocyte development and novel, Ras-independent signals to ERK that have been identified in peripheral T cells.
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Affiliation(s)
- Robert L Kortum
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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19
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Golec DP, Dower NA, Stone JC, Baldwin TA. RasGRP1, but not RasGRP3, is required for efficient thymic β-selection and ERK activation downstream of CXCR4. PLoS One 2013; 8:e53300. [PMID: 23308188 PMCID: PMC3538756 DOI: 10.1371/journal.pone.0053300] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 11/30/2012] [Indexed: 01/19/2023] Open
Abstract
T cell development is a highly dynamic process that is driven by interactions between developing thymocytes and the thymic microenvironment. Upon entering the thymus, the earliest thymic progenitors, called CD4−CD8− ‘double negative’ (DN) thymocytes, pass through a checkpoint termed “β-selection” before maturing into CD4+CD8+ ‘double positive’ (DP) thymocytes. β-selection is an important developmental checkpoint during thymopoiesis where developing DN thymocytes that successfully express the pre-T cell receptor (TCR) undergo extensive proliferation and differentiation towards the DP stage. Signals transduced through the pre-TCR, chemokine receptor CXCR4 and Notch are thought to drive β-selection. Additionally, it has long been known that ERK is activated during β-selection; however the pathways regulating ERK activation remain unknown. Here, we performed a detailed analysis of the β-selection events in mice lacking RasGRP1, RasGRP3 and RasGRP1 and 3. We report that RasGRP1 KO and RasGRP1/3 DKO deficient thymi show a partial developmental block at the early DN3 stage of development. Furthermore, DN3 thymocytes from RasGRP1 and RasGRP1/3 double knock-out thymi show significantly reduced proliferation, despite expression of the TCRβ chain. As a result of impaired β-selection, the pool of TCRβ+ DN4 is significantly diminished, resulting in inefficient DN to DP development. Also, we report that RasGRP1 is required for ERK activation downstream of CXCR4 signaling, which we hypothesize represents a potential mechanism of RasGRP1 regulation of β-selection. Our results demonstrate that RasGRP1 is an important regulator of proliferation and differentiation at the β-selection checkpoint and functions downstream of CXCR4 to activate the Ras/MAPK pathway.
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Affiliation(s)
- Dominic P. Golec
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Nancy A. Dower
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - James C. Stone
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Troy A. Baldwin
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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20
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GPCR activation of Ras and PI3Kc in neutrophils depends on PLCb2/b3 and the RasGEF RasGRP4. EMBO J 2012; 31:3118-29. [PMID: 22728827 PMCID: PMC3400018 DOI: 10.1038/emboj.2012.167] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 05/15/2012] [Indexed: 12/31/2022] Open
Abstract
The molecular mechanisms by which receptors regulate the Ras Binding Domains of the PIP3-generating, class I PI3Ks remain poorly understood, despite their importance in a range of biological settings, including tumorigenesis, activation of neutrophils by pro-inflammatory mediators, chemotaxis of Dictyostelium and cell growth in Drosophila. We provide evidence that G protein-coupled receptors (GPCRs) can stimulate PLCb2/b3 and diacylglycerol- dependent activation of the RasGEF, RasGRP4 in neutrophils. The genetic loss of RasGRP4 phenocopies knock-in of a Ras-insensitive version of PI3Kc in its effects on PI3Kc-dependent PIP3 accumulation, PKB activation, chemokinesis and reactive oxygen species (ROS) formation. These results establish a new mechanism by which GPCRs can stimulate Ras, and the broadly important principle that PLCs can control activation of class I PI3Ks.
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Adachi R, Krilis SA, Nigrovic PA, Hamilton MJ, Chung K, Thakurdas SM, Boyce JA, Anderson P, Stevens RL. Ras guanine nucleotide-releasing protein-4 (RasGRP4) involvement in experimental arthritis and colitis. J Biol Chem 2012; 287:20047-55. [PMID: 22511759 DOI: 10.1074/jbc.m112.360388] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
RasGRP4 (Ras guanine nucleotide-releasing protein-4) is an intracellular, calcium-regulated guanine nucleotide exchange factor and diacylglycerol/phorbol ester receptor expressed in mast cells (MCs) and their progenitors. To study the function of this signaling protein in inflammatory disorders, a homologous recombination approach was used to create a RasGRP4-null C57BL/6 mouse line. The resulting transgenic animals had normal numbers of MCs in their tissues that histochemically and morphologically resembled those in WT C57BL/6 mice. MCs could also be generated from RasGRP4-null mice by culturing their bone marrow cells in IL-3-enriched conditioned medium. Despite these data, the levels of the transcripts that encode the proinflammatory cytokines IL-1β and TNF-α were reduced in phorbol 12-myristate 13-acetate-treated MCs developed from RasGRP4-null mice. Although inflammation was not diminished in a Dermatophagoides farinae-dependent model of allergic airway disease, dextran sodium sulfate-induced colitis was significantly reduced in RasGRP4-null mice relative to similarly treated WT mice. Furthermore, experimental arthritis could not be induced in RasGRP4-null mice that had received K/BxN mouse serum. The latter findings raise the possibility that the pharmacologic inactivation of this intracellular signaling protein might be an effective treatment for arthritis or inflammatory bowel disease.
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Affiliation(s)
- Roberto Adachi
- Department of Pulmonary Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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