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Srivastava T, Garola RE, Zhou J, Boinpelly VC, Rezaiekhaligh MH, Joshi T, Jiang Y, Ebadi D, Sharma S, Sethna C, Staggs VS, Sharma R, Gipson DS, Hao W, Wang Y, Mariani LH, Hodgin JB, Rottapel R, Yoshitaka T, Ueki Y, Sharma M. Scaffold protein SH3BP2 signalosome is pivotal for immune activation in nephrotic syndrome. JCI Insight 2024; 9:e170055. [PMID: 38127456 PMCID: PMC10967477 DOI: 10.1172/jci.insight.170055] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 12/19/2023] [Indexed: 12/23/2023] Open
Abstract
Despite clinical use of immunosuppressive agents, the immunopathogenesis of minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) remains unclear. Src homology 3-binding protein 2 (SH3BP2), a scaffold protein, forms an immune signaling complex (signalosome) with 17 other proteins, including phospholipase Cγ2 (PLCγ2) and Rho-guanine nucleotide exchange factor VAV2 (VAV2). Bioinformatic analysis of human glomerular transcriptome (Nephrotic Syndrome Study Network cohort) revealed upregulated SH3BP2 in MCD and FSGS. The SH3BP2 signalosome score and downstream MyD88, TRIF, and NFATc1 were significantly upregulated in MCD and FSGS. Immune pathway activation scores for Toll-like receptors, cytokine-cytokine receptor, and NOD-like receptors were increased in FSGS. Lower SH3BP2 signalosome score was associated with MCD, higher estimated glomerular filtration rate, and remission. Further work using Sh3bp2KI/KI transgenic mice with a gain-in-function mutation showed ~6-fold and ~25-fold increases in albuminuria at 4 and 12 weeks, respectively. Decreased serum albumin and unchanged serum creatinine were observed at 12 weeks. Sh3bp2KI/KI kidney morphology appeared normal except for increased mesangial cellularity and patchy foot process fusion without electron-dense deposits. SH3BP2 co-immunoprecipitated with PLCγ2 and VAV2 in human podocytes, underscoring the importance of SH3BP2 in immune activation. SH3BP2 and its binding partners may determine the immune activation pathways resulting in podocyte injury leading to loss of the glomerular filtration barrier.
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Affiliation(s)
- Tarak Srivastava
- Section of Nephrology, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, Missouri, USA
- Midwest Veterans’ Biomedical Research Foundation, Kansas City, Missouri, USA
- Department of Oral and Craniofacial Sciences, University of Missouri at Kansas City School of Dentistry, Kansas City, Missouri, USA
| | - Robert E. Garola
- Department of Pathology and Laboratory Medicine, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, Missouri, USA
| | - Jianping Zhou
- Midwest Veterans’ Biomedical Research Foundation, Kansas City, Missouri, USA
- Kansas City VA Medical Center, Kansas City, Missouri, USA
| | - Varun C. Boinpelly
- Midwest Veterans’ Biomedical Research Foundation, Kansas City, Missouri, USA
- Kansas City VA Medical Center, Kansas City, Missouri, USA
| | - Mohammad H. Rezaiekhaligh
- Section of Nephrology, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, Missouri, USA
| | - Trupti Joshi
- Department of Health Management and Informatics
- Department of Electrical Engineering and Computer Science
- Christopher S. Bond Life Sciences Center, and
- MU Institute for Data Science and Informatics, University of Missouri, Columbia, Missouri, USA
| | - Yuexu Jiang
- Department of Electrical Engineering and Computer Science
- Christopher S. Bond Life Sciences Center, and
| | - Diba Ebadi
- The Ottawa Hospital Rehabilitation Centre, Ottawa, Ontario, Canada
| | - Siddarth Sharma
- Milken Institute School of Public Health, George Washington University, Washington, DC, USA
| | - Christine Sethna
- Cohen Children’s Medical Center of NY, New Hyde Park, New York, USA
| | - Vincent S. Staggs
- Biostatistics and Epidemiology Core, Children’s Mercy Research Institute and Department of Pediatrics, University of Missouri, Kansas City, Missouri, USA
| | - Ram Sharma
- Kansas City VA Medical Center, Kansas City, Missouri, USA
- Department of Internal Medicine, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Debbie S. Gipson
- Division of Nephrology, Department of Internal Medicine, School of Medicine, and
| | - Wei Hao
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA
| | - Yujie Wang
- Division of Nephrology, Department of Internal Medicine, School of Medicine, and
| | - Laura H. Mariani
- Division of Nephrology, Department of Internal Medicine, School of Medicine, and
| | - Jeffrey B. Hodgin
- Division of Nephrology, Department of Internal Medicine, School of Medicine, and
| | - Robert Rottapel
- Princess Margaret Cancer Center, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Teruhito Yoshitaka
- Department of Orthopedic Surgery, Hiroshima City Rehabilitation Hospital, Hiroshima, Hiroshima, Japan
| | - Yasuyoshi Ueki
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, Indiana, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Mukut Sharma
- Midwest Veterans’ Biomedical Research Foundation, Kansas City, Missouri, USA
- Kansas City VA Medical Center, Kansas City, Missouri, USA
- Department of Internal Medicine, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
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Mukai T, Ishida S, Ishikawa R, Yoshitaka T, Kittaka M, Gallant R, Lin YL, Rottapel R, Brotto M, Reichenberger EJ, Ueki Y. SH3BP2 cherubism mutation potentiates TNF-α-induced osteoclastogenesis via NFATc1 and TNF-α-mediated inflammatory bone loss. J Bone Miner Res 2014; 29:2618-35. [PMID: 24916406 PMCID: PMC4262741 DOI: 10.1002/jbmr.2295] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 05/19/2014] [Accepted: 06/02/2014] [Indexed: 01/03/2023]
Abstract
Cherubism (OMIM# 118400) is a genetic disorder with excessive jawbone resorption caused by mutations in SH3 domain binding protein 2 (SH3BP2), a signaling adaptor protein. Studies on the mouse model for cherubism carrying a P416R knock-in (KI) mutation have revealed that mutant SH3BP2 enhances tumor necrosis factor (TNF)-α production and receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation in myeloid cells. TNF-α is expressed in human cherubism lesions, which contain a large number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells, and TNF-α plays a critical role in inflammatory bone destruction in homozygous cherubism mice (Sh3bp2(KI/KI) ). The data suggest a pathophysiological relationship between mutant SH3BP2 and TNF-α-mediated bone loss by osteoclasts. Therefore, we investigated whether P416R mutant SH3BP2 is involved in TNF-α-mediated osteoclast formation and bone loss. Here, we show that bone marrow-derived M-CSF-dependent macrophages (BMMs) from the heterozygous cherubism mutant (Sh3bp2(KI/+) ) mice are highly responsive to TNF-α and can differentiate into osteoclasts independently of RANKL in vitro by a mechanism that involves spleen tyrosine kinase (SYK) and phospholipase Cγ2 (PLCγ2) phosphorylation, leading to increased nuclear translocation of NFATc1. The heterozygous cherubism mutation exacerbates bone loss with increased osteoclast formation in a mouse calvarial TNF-α injection model as well as in a human TNF-α transgenic mouse model (hTNFtg). SH3BP2 knockdown in RAW264.7 cells results in decreased TRAP-positive multinucleated cell formation. These findings suggest that the SH3BP2 cherubism mutation can cause jawbone destruction by promoting osteoclast formation in response to TNF-α expressed in cherubism lesions and that SH3BP2 is a key regulator for TNF-α-induced osteoclastogenesis. Inhibition of SH3BP2 expression in osteoclast progenitors could be a potential strategy for the treatment of bone loss in cherubism as well as in other inflammatory bone disorders.
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Affiliation(s)
- Tomoyuki Mukai
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, USA
| | - Shu Ishida
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, USA
- Department of Periodontal Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, JAPAN
| | - Remi Ishikawa
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, USA
- Department of Molecular Biology and Biochemistry, Okayama University Medical School, Okayama, JAPAN
| | - Teruhito Yoshitaka
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, USA
| | - Mizuho Kittaka
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, USA
- Department of Periodontal Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, JAPAN
| | - Richard Gallant
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, USA
| | - Yi-Ling Lin
- UCLA School of Dentistry, Los Angeles, CA, USA
| | - Robert Rottapel
- Ontario Cancer Institute and the Campbell Family Cancer Research Institute, University of Toronto, Toronto, Canada
- Division of Rheumatology, Department of Medicine, Saint Michael's Hospital, Toronto, Canada
| | - Marco Brotto
- School of Nursing & Health Studies and School of Medicine, University of Missouri-Kansas City, MO, USA
| | - Ernst J. Reichenberger
- Department of Reconstructive Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT, USA
| | - Yasuyoshi Ueki
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, USA
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Tai WT, Chu PY, Shiau CW, Chen YL, Li YS, Hung MH, Chen LJ, Chen PL, Su JC, Lin PY, Yu HC, Chen KF. STAT3 mediates regorafenib-induced apoptosis in hepatocellular carcinoma. Clin Cancer Res 2014; 20:5768-76. [PMID: 25248379 DOI: 10.1158/1078-0432.ccr-14-0725] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE Here, we aim to investigate the molecular mechanism of regorafenib and verify the potential druggable target for the treatment of hepatocellular carcinoma (HCC). EXPERIMENTAL DESIGN HCC cell lines (PLC5, HepG2, Hep3B, SK-Hep1, and HA59T) were used to investigate the in vitro effect of regorafenib. Phosphatase activity was analyzed in HCC cells and purified SHP-1 proteins. PLC5-bearing mice were used to test the therapeutic efficiency of 20 and 40 mg/kg/d treatment with regorafenib ([Formula: see text] mice). The clinical relevance of STAT3 signaling was investigated with 142 tumor samples from different patients with HCC. Descriptive statistical analysis was used to compare the baseline characteristics of patients and the expression of p-STAT3. RESULTS Regorafenib inhibited STAT3-related signaling in a dose-dependent manner and was a more potent inhibitor of STAT3 than sorafenib. Regorafenib increased SHP-1 phosphatase activity in purified SHP-1 protein directly. N-SH2 domain deletion and D61A mutants mimicking open-form SHP-1 partially abolished regorafenib-induced STAT3 inhibition and apoptosis. Importantly, a higher level of expression of STAT3 was found in patients with advanced clinical stages (P = 0.009) and poorly differentiated tumors (P = 0.035). CONCLUSIONS Regorafenib induced significant tumor inhibition by relieving the autoinhibited N-SH2 domain of SHP-1 directly and inhibiting p-STAT3 signals. STAT3 may be suitable as a prognostic marker of HCC development, and may be a druggable target for HCC-targeted therapy using regorafenib.
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Affiliation(s)
- Wei-Tien Tai
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan. National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Pei-Yi Chu
- Department of Pathology, Show Chwan Memorial Hospital, Changhua City, Taiwan. School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Chung-Wai Shiau
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Yao-Li Chen
- Department of Surgery, Changhua Christian Hospital, Changhua, Taiwan
| | - Yong-Shi Li
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan. National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Man-Hsin Hung
- Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. Program in Molecular Medicine, School of Life Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Li-Ju Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan. National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Pei-Lung Chen
- Graduate Institute of Medical Genomics and Proteomics, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Jung-Chen Su
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Ping-Yi Lin
- Department of Surgery, Changhua Christian Hospital, Changhua, Taiwan
| | - Hui-Chuan Yu
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan. National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Kuen-Feng Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan. National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan.
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Peng G, Cao RB, Li YH, Zou ZW, Huang J, Ding Q. Alterations of cell cycle control proteins SHP‑1/2, p16, CDK4 and cyclin D1 in radioresistant nasopharyngeal carcinoma cells. Mol Med Rep 2014; 10:1709-16. [PMID: 25109634 PMCID: PMC4148372 DOI: 10.3892/mmr.2014.2463] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 05/21/2014] [Indexed: 12/12/2022] Open
Abstract
The primary treatment for nasopharyngeal carcinoma (NPC) is radiotherapy, with or without concurrent chemotherapy. However, resistance to radiotherapy is not uncommon. The aim of the present study was to establish a radioresistant NPC cell line to study the molecular mechanisms of radioresistance by measuring the expression of cell cycle control proteins src homology 2 domain-containing phosphatase (SHP)-1/2, p16, CDK4 and cyclin D1. Human nasopharyngeal carcinoma CNE-2 cells were cultured, divided into two groups (CNE-2S1 and CNE-2S2) and irradiated with a dose of 6 Gy x5 or 2 Gy x15, respectively. The cells were subcultured between doses of irradiation. The surviving sublines (CNE-2S1 and CNE-2S2 clones) were then passaged for three months and their radiosensitivity was determined. The cell cycle distribution and protein expression of SHP-1/2, p16, CDK4 and cyclin D1 in parental and progenitor cell lines were measured. Small interfering (si)RNA-mediated knockdown of SHP-1 and SHP-2 in the NPC cells was used to further examine their roles in radiosensitivity and cell cycle distribution. CNE-2S1, a radio-resistant cell line, had a significantly higher percentage of cells in S phase and a lower percentage of cells in G1 phase, enhanced expression levels of SHP-1, CDK4 and cyclin D1, and reduced expression of p16, respectively, as compared with the parent cells. Stable suppression of SHP-1 mRNA in CNE-2 cells resulted in increased radiosensitivity compared with the parental cells, a decrease in the number of cells in S phase and an increase in the expression of p16. The results suggested that the SHP-1/p16/cyclin D1/CDK4 pathway may have a role in regulating radiosensitivity and cell cycle distribution in nasopharyngeal cells.
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Affiliation(s)
- Gang Peng
- Department of Head and Neck Cancer, Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Ru-Bo Cao
- Department of Head and Neck Cancer, Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Yue-Hua Li
- Department of Head and Neck Cancer, Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Zhen-Wei Zou
- Department of Head and Neck Cancer, Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Jing Huang
- Department of Head and Neck Cancer, Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Qian Ding
- Department of Head and Neck Cancer, Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
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Yoshitaka T, Ishida S, Mukai T, Kittaka M, Reichenberger EJ, Ueki Y. Etanercept administration to neonatal SH3BP2 knock-in cherubism mice prevents TNF-α-induced inflammation and bone loss. J Bone Miner Res 2014; 29:1170-82. [PMID: 24978678 PMCID: PMC4131552 DOI: 10.1002/jbmr.2125] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 09/30/2013] [Accepted: 10/14/2013] [Indexed: 12/19/2022]
Abstract
Cherubism is a genetic disorder of the craniofacial skeleton caused by gain-of-function mutations in the signaling adaptor protein, SH3-domain binding protein 2 (SH3BP2). In a knock-in mouse model for cherubism, we previously demonstrated that homozygous mutant mice develop T/B cell-independent systemic macrophage inflammation leading to bone erosion and joint destruction. Homozygous mice develop multiostotic bone lesions whereas cherubism lesions in humans are limited to jawbones. We identified a critical role of tumor necrosis factor α (TNF-α) in the development of autoinflammation by creating homozygous TNF-α-deficient cherubism mutants, in which systemic inflammation and bone destruction were rescued. In this study, we examined whether postnatal administration of an anti-TNF-α antagonist can prevent or ameliorate the disease progression in cherubism mice. Neonatal homozygous mutants, in which active inflammation has not yet developed, were treated with a high dose of etanercept (25 mg/kg, twice/week) for 7 weeks. Etanercept-treated neonatal mice showed strong rescue of facial swelling and bone loss in jaws and calvariae. Destruction of joints was fully rescued in the high-dose group. Moreover, the high-dose treatment group showed a significant decrease in lung and liver inflammatory lesions. However, inflammation and bone loss, which were successfully treated by etanercept administration, recurred after etanercept discontinuation. No significant effect was observed in low-dose-treated (0.5 mg/kg, twice/week) and vehicle-treated groups. In contrast, when 10-week-old cherubism mice with fully active inflammation were treated with etanercept for 7 weeks, even the high-dose administration did not decrease bone loss or lung or liver inflammation. Taken together, the results suggest that anti-TNF-α therapy may be effective in young cherubism patients, if treated before the inflammatory phase or bone resorption occurs. Therefore, early genetic diagnosis and early treatment with anti-TNF-α antagonists may be able to prevent or ameliorate cherubism, especially in patients with a mutation in SH3BP2.
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Affiliation(s)
- Teruhito Yoshitaka
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
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Cao R, Ding Q, Li P, Xue J, Zou Z, Huang J, Peng G. SHP1-mediated cell cycle redistribution inhibits radiosensitivity of non-small cell lung cancer. Radiat Oncol 2013; 8:178. [PMID: 23842094 PMCID: PMC3723552 DOI: 10.1186/1748-717x-8-178] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 07/02/2013] [Indexed: 12/25/2022] Open
Abstract
Background Radioresistance is the common cause for radiotherapy failure in non-small cell lung cancer (NSCLC), and the degree of radiosensitivity of tumor cells is different during different cell cycle phases. The objective of the present study was to investigate the effects of cell cycle redistribution in the establishment of radioresistance in NSCLC, as well as the signaling pathway of SH2 containing Tyrosine Phosphatase (SHP1). Methods A NSCLC subtype cell line, radioresistant A549 (A549S1), was induced by high-dose hypofractionated ionizing radiations. Radiosensitivity-related parameters, cell cycle distribution and expression of cell cycle-related proteins and SHP1 were investigated. siRNA was designed to down-regulate SHP1expression. Results Compared with native A549 cells, the proportion of cells in the S phase was increased, and cells in the G0/G1 phase were consequently decreased, however, the proportion of cells in the G2/M phase did not change in A549S1 cells. Moreover, the expression of SHP1, CDK4 and CylinD1 were significantly increased, while p16 was significantly down-regulated in A549S1 cells compared with native A549 cells. Furthermore, inhibition of SHP1 by siRNA increased the radiosensitivity of A549S1 cells, induced a G0/G1 phase arrest, down-regulated CDK4 and CylinD1expressions, and up-regulated p16 expression. Conclusions SHP1 decreases the radiosensitivity of NSCLC cells through affecting cell cycle distribution. This finding could unravel the molecular mechanism involved in NSCLC radioresistance.
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Affiliation(s)
- Rubo Cao
- Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No, 1227 Jiefang Dadao, Wuhan 430022, China
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Ainsua-Enrich E, Alvarez-Errico D, Gilfillan AM, Picado C, Sayós J, Rivera J, Martín M. The adaptor 3BP2 is required for early and late events in FcεRI signaling in human mast cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 189:2727-34. [PMID: 22896635 PMCID: PMC3436965 DOI: 10.4049/jimmunol.1200380] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Adaptor molecules are essential in organizing signaling molecules and in coordinating and compartmentalizing their activity. SH3-binding protein 2 (3BP2) is a cytoplasmic adaptor protein mainly expressed by hematopoietic cells that has been shown to act as a positive regulator in T, B, and NK cell signal transduction. 3BP2 is an important regulator of cytotoxic granule release in NK cells. Mast cells (MCs) similarly degranulate following Ag-dependent aggregation of the FcεRI on the cell surface. Activation of these cells induces the release of preformed inflammatory mediators and the de novo synthesis and secretion of cytokines and chemokines. Thus, MCs participate in both innate and acquired responses. We observed that 3BP2 is expressed in human MCs (huMCs) from diverse origins. Moreover, 3BP2 coimmunoprecipitates with essential MC signaling mediators such as Lyn, Syk, and phospholipase C γ; thus, a role for this adaptor in MC function was postulated. In the present work, we used the short hairpin RNA lentiviral targeting approach to silence 3BP2 expression in huMCs. Our findings point to a requirement for 3BP2 in optimal immediate and late MCs responses such as degranulation and IL-8 or GM-CSF secretion. 3BP2 was determined to be necessary for optimal phosphorylation of Syk, linker for activation of T cells, and phospholipase C γ(1), critical signals for calcium release from intracellular stores. Taken together, our results show that by participating in FcεRI- mediated signal transduction 3BP2 is an important regulator of huMC activation. Thus, 3BP2 could be a potential therapeutic target for IgE-dependent MC-mediated inflammatory disease.
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Affiliation(s)
- Erola Ainsua-Enrich
- Biochemistry Unit, Faculty of Medicine, University of Barcelona, 08036 Barcelona, Spain
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Reichenberger EJ, Levine MA, Olsen BR, Papadaki ME, Lietman SA. The role of SH3BP2 in the pathophysiology of cherubism. Orphanet J Rare Dis 2012; 7 Suppl 1:S5. [PMID: 22640988 PMCID: PMC3359958 DOI: 10.1186/1750-1172-7-s1-s5] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cherubism is a rare bone dysplasia that is characterized by symmetrical bone resorption limited to the jaws. Bone lesions are filled with soft fibrous giant cell-rich tissue that can expand and cause severe facial deformity. The disorder typically begins in children at ages of 2-5 years and the bone resorption and facial swelling continues until puberty; in most cases the lesions regress spontaneously thereafter. Most patients with cherubism have germline mutations in the gene encoding SH3BP2, an adapter protein involved in adaptive and innate immune response signaling. A mouse model carrying a Pro416Arg mutation in SH3BP2 develops osteopenia and expansile lytic lesions in bone and some soft tissue organs. In this review we discuss the genetics of cherubism, the biological functions of SH3BP2 and the analysis of the mouse model. The data suggest that the underlying cause for cherubism is a systemic autoinflammatory response to physiologic challenges despite the localized appearance of bone resorption and fibrous expansion to the jaws in humans.
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Affiliation(s)
- Ernst J Reichenberger
- Department of Reconstructive Sciences, Center for Regenerative Medicine and Skeletal Development, University of Connecticut Health Center, Farmington, CT, USA.
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Abstract
T cell recognition of antigen is a crucial aspect of the adaptive immune response. One of the most common means of pathogen immune evasion is mutation of T cell epitopes. T cell recognition of such ligands can result in a variety of outcomes including activation, apoptosis and anergy. The ability of a given T cell to respond to a specific peptide-MHC ligand is regulated by a number of factors, including the affinity, on- and off-rates and half-life of the TCR-peptide-MHC interaction. Interaction of T cells with low-potency ligands results in unique signaling patterns and requires engagement with a larger number of T cell receptors than agonist ligands. This review will address these aspects of T cell interaction with weak ligands and the ways in which these ligands have been utilized therapeutically.
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Abstract
Tyrosyl phosphorylation plays a critical role in multiple signaling pathways regulating innate and acquired immunity. Although tyrosyl phosphorylation is a reversible process, we know much more about the functions of protein-tyrosine kinases (PTKs) than about protein-tyrosine phosphatases (PTPs). Genome sequencing efforts have revealed a large and diverse superfamily of PTPs, which can be subdivided into receptor-like (RPTPs) and nonreceptor (NRPTPs). The role of the RPTP CD45 in immune cell signaling is well known, but those of most other PTPs remain poorly understood. Here, we review the mechanism of action, regulation, and physiological functions of NRPTPs in immune cell signaling. Such an analysis indicates that PTPs are as important as PTKs in regulating the immune system.
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Affiliation(s)
- Lily I Pao
- Cancer Biology Program, Division of Hematology-Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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