1
|
Bussel JB, Soff G, Balduzzi A, Cooper N, Lawrence T, Semple JW. A Review of Romiplostim Mechanism of Action and Clinical Applicability. Drug Des Devel Ther 2021; 15:2243-2268. [PMID: 34079225 PMCID: PMC8165097 DOI: 10.2147/dddt.s299591] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 05/06/2021] [Indexed: 12/17/2022] Open
Abstract
Thrombocytopenia results from a variety of conditions, including radiation, chemotherapy, autoimmune disease, bone marrow disorders, pathologic conditions associated with surgical procedures, hematopoietic stem cell transplant (HSCT), and hematologic disorders associated with severe aplastic anemia. Immune thrombocytopenia (ITP) is caused by immune reactions that accelerate destruction and reduce production of platelets. Thrombopoietin (TPO) is a critical component of platelet production pathways, and TPO receptor agonists (TPO-RAs) are important for the management of ITP by increasing platelet production and reducing the need for other treatments. Romiplostim is a TPO-RA approved for use in patients with ITP in the United States, European Union, Australia, and several countries in Africa and Asia, as well as for use in patients with refractory aplastic anemia in Japan and Korea. Romiplostim binds to and activates the TPO receptor on megakaryocyte precursors, thus promoting cell proliferation and viability, resulting in increased platelet production. Through this mechanism, romiplostim reduces the need for other treatments and decreases bleeding events in patients with thrombocytopenia. In addition to its efficacy in ITP, studies have shown that romiplostim is effective in improving platelet counts in various settings, thereby highlighting the versatility of romiplostim. The efficacy of romiplostim in such disorders is currently under investigation. Here, we review the structure, mechanism, pharmacokinetics, and pharmacodynamics of romiplostim. We also summarize the clinical evidence supporting its use in ITP and other disorders that involve thrombocytopenia, including chemotherapy-induced thrombocytopenia, aplastic anemia, acute radiation syndrome, perisurgical thrombocytopenia, post-HSCT thrombocytopenia, and liver disease.
Collapse
Affiliation(s)
- James B Bussel
- Department of Pediatrics, Division of Hematology, Weill Cornell Medicine, New York, NY, USA
| | - Gerald Soff
- Department of Medicine, Hematology Service, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Adriana Balduzzi
- Clinica Pediatrica Università degli Studi di Milano Bicocca, Ospedale San Gerardo, Monza, Italy
| | | | | | - John W Semple
- Division of Hematology and Transfusion Medicine, Lund University, Lund, Sweden
- Department of Pharmacology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
2
|
Houck KL, Yuan H, Tian Y, Solomon M, Cramer D, Liu K, Zhou Z, Wu X, Zhang J, Oehler V, Dong JF. Physical proximity and functional cooperation of glycoprotein 130 and glycoprotein VI in platelet membrane lipid rafts. J Thromb Haemost 2019; 17:1500-1510. [PMID: 31145836 DOI: 10.1111/jth.14525] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/28/2019] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Clinical and laboratory studies have demonstrated that platelets become hyperactive and prothrombotic in conditions of inflammation. We have previously shown that the proinflammatory cytokine interleukin (IL)-6 forms a complex with soluble IL-6 receptor α (sIL-6Rα) to prime platelets for activation by subthreshold concentrations of collagen. Upon being stimulated with collagen, the transcription factor signal transducer and activator of transcription (STAT) 3 in platelets is phosphorylated and dimerized to act as a protein scaffold to facilitate the catalytic action between the kinase Syk and the substrate phospholipase Cγ2 (PLCγ2) in collagen-induced signaling. However, it remains unknown how collagen induces phosphorylation and dimerization of STAT3. METHODS AND RESULTS We conducted complementary in vitro experiments to show that the IL-6 receptor subunit glycoprotein 130 (GP130) was in physical proximity to the collagen receptor glycoprotein VI (GPVI in membrane lipid rafts of platelets. This proximity allows collagen to induce STAT3 activation and dimerization, and the IL-6-sIL-6Rα complex to activate the kinase Syk and the substrate PLCγ2 in the GPVI signal pathway, resulting in an enhanced platelet response to collagen. Disrupting lipid rafts or blocking GP130-Janus tyrosine kinase (JAK)-STAT3 signaling abolished the cross-activation and reduced platelet reactivity to collagen. CONCLUSION These results demonstrate cross-talk between collagen and IL-6 signal pathways. This cross-talk could potentially provide a novel mechanism for inflammation-induced platelet hyperactivity, so the IL-6-GP130-JAK-STAT3 pathway has been identified as a potential target to block this hyperactivity.
Collapse
Affiliation(s)
| | - Hengjie Yuan
- Tianjin Neurological Institute, General Hospital, Tianjin Medical University, Tianjin, China
| | - Ye Tian
- Tianjin Neurological Institute, General Hospital, Tianjin Medical University, Tianjin, China
| | | | - Drake Cramer
- Bloodworks Research Institute, Seattle, Washington
| | - Kitty Liu
- Bloodworks Research Institute, Seattle, Washington
| | - Zhou Zhou
- State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Beijing, China
| | - Xiaoping Wu
- Bloodworks Research Institute, Seattle, Washington
| | - Jianning Zhang
- Tianjin Neurological Institute, General Hospital, Tianjin Medical University, Tianjin, China
| | - Vivian Oehler
- Clinical Research Division, Hutchison Cancer Center, Seattle, Washington
- Seattle Cancer Alliances, Seattle, Washington
- Division of Hematology, Department of Medicine, School of Medicine, University of Washington, Seattle, Washington
| | - Jing-Fei Dong
- Bloodworks Research Institute, Seattle, Washington
- Division of Hematology, Department of Medicine, School of Medicine, University of Washington, Seattle, Washington
| |
Collapse
|
3
|
Radakovich LB, Marolf AJ, Culver LA, Santangelo KS. Calorie restriction with regular chow, but not a high-fat diet, delays onset of spontaneous osteoarthritis in the Hartley guinea pig model. Arthritis Res Ther 2019; 21:145. [PMID: 31196172 PMCID: PMC6567638 DOI: 10.1186/s13075-019-1925-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 05/23/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Obesity is a leading risk factor for osteoarthritis (OA). In contrast, calorie restriction (CR) may lessen OA due to improved systemic inflammatory status and reduced weight-bearing. The aim of this study was to determine how CR with regular chow versus a high-fat diet (HFD) alters OA progression using the Hartley guinea pig model of disease. METHODS Twenty-four male guinea pigs were allocated to four groups at 2 months of age: (1) ad libitum regular chow (obese), (2) CR regular chow (lean), (3) ad libitum HFD, and (4) CR HFD. Animals in both HFD groups ate identical amounts and were combined into one HFD group for analyses. At 5 months, hind limbs were harvested for microcomputed tomography (microCT) and histopathologic evaluation of knee OA. Total body, gonad fat, and infrapatellar fat pad (IFP) masses were recorded. IFPs were collected for gene expression analysis. Immunohistochemistry for monocyte chemoattractant protein-1 (MCP-1) was performed on intact joints. Serum was utilized for protein C3 measurement. All data were compared using ordinary one-way ANOVA analyses with Tukey's post-hoc tests. RESULTS Body mass in the lean and HFD groups were similar and lower than the obese group. Despite this, gonad fat pads in the HFD group were comparable to the obese group. MicroCT and histologic OA scores were similar in obese and HFD groups; both scores were significantly lower in the lean group. Obese and HFD groups displayed increased gene expression of pro-inflammatory and catabolic mediators in IFPs relative to lean animals. Consistent with this, immunohistochemistry for MCP-1 in knee joints demonstrated strong positive staining in obese and HFD groups but was minimally detected in lean animals. Serum protein C3 levels were also statistically higher. CONCLUSIONS This study demonstrated that CR with a regular chow diet lessened knee OA in the Hartley guinea pig and was associated with decreased local and systemic inflammation compared to obese animals. HFD animals, although under CR conditions, had OA scores and inflammatory markers similar to obese animals. Thus, diet composition, and not solely body weight, may be a key factor in development of OA.
Collapse
Affiliation(s)
- Lauren B. Radakovich
- Department of Microbiology, Immunology, Pathology, Colorado State University, 200 West Lake Street, Fort Collins, CO 80521 USA
| | - Angela J. Marolf
- Department of Environmental and Radiological Health Sciences, Colorado State University, 123 Flint Cancer Center, Fort Collins, CO 80523 USA
| | - Lauren A. Culver
- Department of Microbiology, Immunology, Pathology, Colorado State University, 200 West Lake Street, Fort Collins, CO 80521 USA
| | - Kelly S. Santangelo
- Department of Microbiology, Immunology, Pathology, Colorado State University, 200 West Lake Street, Fort Collins, CO 80521 USA
| |
Collapse
|
4
|
Zeng Q, Xue N, Dai D, Xing S, He X, Li S, Du Y, Huang C, Li L, Liu W. A Nomogram based on Inflammatory Factors C-Reactive Protein and Fibrinogen to Predict the Prognostic Value in Patients with Resected Non-Small Cell Lung Cancer. J Cancer 2017; 8:744-753. [PMID: 28382136 PMCID: PMC5381162 DOI: 10.7150/jca.17423] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/29/2016] [Indexed: 12/13/2022] Open
Abstract
Purpose: This study aimed to develop an effective nomogram for predicting survival in surgically treated non-small cell lung cancer patients. Methods: We retrospectively evaluated 856 NSCLC in this study. Cox regression analyses were performed to identify significant prognostic factors for developing a nomogram to predict overall survival (OS). The discriminative ability was assessed with the concordance index (C-index). Results: On multivariate analysis of the 856 cohort, independent factors for survival were CRP, fibrinogen, tumor status, nodal status, distant metastasis and clinical stage, which were entered into the nomogram. The C-index of the established nomogram 0.720 (95% CI: 0.671-0.769) was higher than that of the seventh edition TNM staging system 0.689 (95% CI: 0.668-0.709) for predicting OS (P < 0.05). Compared with patients with low CRP levels (< 8.6 g/L) and low fibrinogen levels (< 3.7 g/L), patients with high CRP and fibrinogen levels had shorter OS. Subgroup analyses revealed that the nomogram was a favorable prognostic parameter in stage I-IV NSCLC (P < 0.05). Conclusion: A nomogram integrating CRP and fibrinogen, which could be convenient and feasible to obtain from the serum preoperatively, may assist in risk stratification for individual patient with resected NSCLC.
Collapse
Affiliation(s)
- Qiuyao Zeng
- State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China;; Department of Clinical Laboratory, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Ning Xue
- State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China;; Department of Experimental Research, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Danian Dai
- State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China;; Department of Breast Oncology, Sun Yat-Sen University Cancer Center, Guangzhou, China
| | - Shan Xing
- State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China;; Department of Clinical Laboratory, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Xia He
- State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China;; Department of Clinical Laboratory, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Shibing Li
- State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China;; Department of Experimental Research, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Yi Du
- School of Medical Laboratory Science, Guangdong Medical University, Dongguan, China
| | - Chumei Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Linfang Li
- State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China;; Department of Clinical Laboratory, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Wanli Liu
- State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China;; Department of Clinical Laboratory, Sun Yat-sen University Cancer Center, Guangzhou, China
| |
Collapse
|
5
|
Badovinac S, Korsic M, Mursic D, Samarzija M, Cucevic B, Roglic M, Jakopovic M. Cancer-related inflammation as predicting tool for treatment outcome in locally advanced and metastatic non-small cell lung cancer. J Thorac Dis 2016; 8:1497-503. [PMID: 27499936 DOI: 10.21037/jtd.2016.05.56] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Lung cancer is the leading cause of cancer deaths and the non-small cell lung cancer (NSCLC) represents 80% of all cases. In most cases when diagnosed, it is in locally advanced or metastatic stage, when platinum based doublet chemotherapy is the established therapeutic option for majority of the patients. Predictive factors to filter the patients who will benefit the most from the chemotherapy are not clearly defined. Objective of this study was to explore predictive value of pre-treatment C-reactive protein (CRP), fibrinogen and their interaction, for the response to the frontline chemotherapy. METHODS In this retrospective cohort study 170 patients with locally advanced and metastatic NSCLC were included. Relationship between baseline level of CRP and fibrinogen and response to the frontline chemotherapy was assessed. RESULTS We found that pre-treatment CRP and fibrinogen values were statistically significantly correlated. Chemotherapy and CRP, fibrinogen, and their interaction were independently significantly associated with disease control rate at re-evaluation. There was statistically significant difference in median pre-treatment CRP level between the patients with disease control or progression at re-evaluation, 13.8 vs. 30.0 mg/L respectively, P=0.026. By Johnson-Neyman technique we found that in patients with initial fibrinogen value below 3.5 g/L, CRP level was significantly associated with disease control or progression of the disease. Above this fibrinogen value the association of CRP and disease control was lost. CONCLUSIONS The findings from this study support the growing evidence of inflammation and cancer relationship, where elevated pre-treatment level of CRP has negative predictive significance on the NSCLC frontline chemotherapy response.
Collapse
Affiliation(s)
- Sonja Badovinac
- Department for Lung Diseases Jordanovac, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Marta Korsic
- Department for Lung Diseases Jordanovac, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Davorka Mursic
- Department for Lung Diseases Jordanovac, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Miroslav Samarzija
- Department for Lung Diseases Jordanovac, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Branka Cucevic
- Department for Lung Diseases Jordanovac, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Mihovil Roglic
- Department for Lung Diseases Jordanovac, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Marko Jakopovic
- Department for Lung Diseases Jordanovac, University Hospital Centre Zagreb, Zagreb, Croatia
| |
Collapse
|
6
|
The preoperative plasma fibrinogen level is an independent prognostic factor for overall survival of breast cancer patients who underwent surgical treatment. Breast 2015; 24:745-50. [PMID: 26482138 DOI: 10.1016/j.breast.2015.09.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 09/03/2015] [Accepted: 09/15/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Previous studies have suggested that plasma fibrinogen contributes to tumor cell proliferation, progression and metastasis. The current study was performed to evaluate the prognostic relevance of preoperative plasma fibrinogen in breast cancer patients. METHOD Data of 2073 consecutive breast cancer patients, who underwent surgery between January 2002 and December 2008 at the Sun Yat-sen University Cancer Center, were retrospectively evaluated. Plasma fibrinogen levels were routinely measured before surgeries. Participants were grouped by the cutoff value estimated by the receiver operating characteristic (ROC) curve analysis. Overall survival (OS) was assessed using Kaplan-Meier analysis, and multivariate Cox proportional hazards regression model was performed to evaluate the independent prognostic value of plasma fibrinogen level. RESULTS The optimal cutoff value of preoperative plasma fibrinogen was determined to be 2.83 g/L. The Kaplan-Meier analysis showed that patients with high fibrinogen levels had shorter OS than patients with low fibrinogen levels (p < 0.001). Multivariate analysis suggested preoperative plasma fibrinogen as an independent prognostic factor for OS in breast cancer patients (HR = 1.475, 95% confidence interval (CI): 1.177-1.848, p = 0.001). Subgroup analyses revealed that plasma fibrinogen level was an unfavorable prognostic parameter in stage II-III, Luminal subtypes and triple-negative breast cancer patients. CONCLUSION Elevated preoperative plasma fibrinogen was independently associated with poor prognosis in breast cancer patients and may serve as a valuable parameter for risk assessment in breast cancer patients.
Collapse
|
7
|
Mpl expression on megakaryocytes and platelets is dispensable for thrombopoiesis but essential to prevent myeloproliferation. Proc Natl Acad Sci U S A 2014; 111:5884-9. [PMID: 24711413 DOI: 10.1073/pnas.1404354111] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Thrombopoietin (TPO) acting via its receptor, the cellular homologue of the myeloproliferative leukemia virus oncogene (Mpl), is the major cytokine regulator of platelet number. To precisely define the role of specific hematopoietic cells in TPO-dependent hematopoiesis, we generated mice that express the Mpl receptor normally on stem/progenitor cells but lack expression on megakaryocytes and platelets (Mpl(PF4cre/PF4cre)). Mpl(PF4cre/PF4cre) mice displayed profound megakaryocytosis and thrombocytosis with a remarkable expansion of megakaryocyte-committed and multipotential progenitor cells, the latter displaying biological responses and a gene expression signature indicative of chronic TPO overstimulation as the underlying causative mechanism, despite a normal circulating TPO level. Thus, TPO signaling in megakaryocytes is dispensable for platelet production; its key role in control of platelet number is via generation and stimulation of the bipotential megakaryocyte precursors. Nevertheless, Mpl expression on megakaryocytes and platelets is essential to prevent megakaryocytosis and myeloproliferation by restricting the amount of TPO available to stimulate the production of megakaryocytes from the progenitor cell pool.
Collapse
|
8
|
Kim KH, Park TY, Lee JY, Lee SM, Yim JJ, Yoo CG, Kim YW, Han SK, Yang SC. Prognostic significance of initial platelet counts and fibrinogen level in advanced non-small cell lung cancer. J Korean Med Sci 2014; 29:507-11. [PMID: 24753697 PMCID: PMC3991793 DOI: 10.3346/jkms.2014.29.4.507] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 01/21/2014] [Indexed: 01/18/2023] Open
Abstract
Thrombocytosis and coagulation systems activation are commonly associated with disease progression and are suggested poor prognostic factors in patients with malignancies. This study aimed to investigate the prevalence and prognostic significance of thrombocytosis and elevated fibrinogen levels in patients with advanced non-small cell lung cancer (NSCLC). Initial platelet counts and fibrinogen levels were reviewed in 854 patients with histologically proven NSCLC. Thrombocytosis was defined as platelet counts > 450 × 10(9)/L. A serum fibrinogen level > 4.5 g/L was considered high. At the time of diagnosis, initial platelet counts and serum fibrinogen levels were evaluated before treatment. Clinicopathologic data including histological type, tumor, node, metastasis (TNM) stage, performance status, treatment method, and survival time were evaluated. Initial thrombocytosis was found in 6.9% of patients, and elevated fibrinogen levels were found in 55.1% of patients. Patients with thrombocytosis had a significantly poorer prognosis than patients with normal platelet counts (P < 0.001). In multivariate survival analysis, thrombocytosis was an independent prognostic factor (P < 0.001). An elevated serum fibrinogen level was associated with poor prognosis (P < 0.001). In conclusion, initial thrombocytosis and a high fibrinogen level are independent factors for predicting poor prognosis in patients with advanced NSCLC.
Collapse
Affiliation(s)
- Kyung Hee Kim
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Tae Yun Park
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Ji Yeun Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Sang-Min Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Jae-Joon Yim
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Chul-Gyu Yoo
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Young Whan Kim
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Koo Han
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Seok-Chul Yang
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| |
Collapse
|
9
|
Larson MK, Watson SP. A product of their environment: do megakaryocytes rely on extracellular cues for proplatelet formation? Platelets 2007; 17:435-40. [PMID: 17074718 DOI: 10.1080/09537100600772637] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Megakaryocytes have long been observed to form abundant filamentous extensions called proplatelets. A strong body of evidence strongly suggests these proplatelets are the mechanism by which platelets are released into the vasculature. Despite the recent advances in understanding proplatelet architecture, surprisingly little attention has been paid to identifying the ways in which the bone marrow environment regulates proplatelet formation. This review summarises this field and how these findings suggest a spatial and temporal regulation to ensure that platelets are produced in the correct location.
Collapse
Affiliation(s)
- Mark K Larson
- Centre for Cardiovascular Sciences, Institute for Biomedical Research, Division of Medical Sciences, The Medical School, University of Birmingham, Birmingham, UK B15 2TT, UK.
| | | |
Collapse
|
10
|
Larson MK, Watson SP. Regulation of proplatelet formation and platelet release by integrin alpha IIb beta3. Blood 2006; 108:1509-14. [PMID: 16670270 DOI: 10.1182/blood-2005-11-011957] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mature megakaryocytes form structures called proplatelets that serve as conduits for platelet packaging and release at vascular sinusoids. Since the megakaryocyte expresses abundant levels of integrin alpha IIb beta3, we have examined a role for fibrinogen in proplatelet development and platelet release alongside that of other matrices. Primary mature murine megakaryocytes from bone marrow aspirates readily formed proplatelets when plated on fibrinogen at a degree that was significantly higher than that seen on other matrices. In addition, alpha IIb beta3 was essential for proplatelet formation on fibrinogen, as megakaryocytes failed to develop proplatelets in the presence of alpha IIb beta3 antagonists. Interestingly, inhibition of Src kinases or Ca2+ release did not inhibit proplatelet formation, indicating that alpha IIb beta3-mediated outside-in signals are not required for this response. Immunohistochemical studies demonstrated that fibrinogen is localized to the bone marrow sinusoids, a location that would allow it to readily influence platelet release. Further, thrombopoietin-stimulated alpha IIb-/- mice had a reduced increase in platelet number relative to controls. A similar observation was not observed for platelet recovery in alpha IIb-/- mice in response to antibody-induced thrombocytopenia, indicating the existence of additional pathways of regulation of proplatelet formation. These results demonstrate that fibrinogen is able to regulate proplatelet formation via integrin alpha IIb beta3.
Collapse
Affiliation(s)
- Mark K Larson
- Centre for Cardiovascular Sciences, Institute for Biomedical Research, University of Birmingham, United Kingdom.
| | | |
Collapse
|
11
|
Majka M, Ratajczak J, Villaire G, Kubiczek K, Marquez LA, Janowska-Wieczorek A, Ratajczak MZ. Thrombopoietin, but not cytokines binding to gp130 protein-coupled receptors, activates MAPKp42/44, AKT, and STAT proteins in normal human CD34+ cells, megakaryocytes, and platelets. Exp Hematol 2002; 30:751-60. [PMID: 12135673 DOI: 10.1016/s0301-472x(02)00810-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE The development of megakaryocytes is regulated by thrombopoietin (TPO), which binds to the c-mpl receptor, and by several other cytokines such as interleukin (IL)-6, IL-11, leukemia inhibitory factor (LIF), cilliary neurotropic factor (CNTF), and oncostatin (OSM), which bind to gp130 protein-coupled receptors. We attempted to identify signal transduction pathways activated by these factors in normal human megakaryocytes. MATERIALS AND METHODS To better understand the role of these factors in normal human megakaryopoiesis we studied their effect on 1) purified human bone marrow-derived CD34+ cells, 2) human alpha(IIb)beta3+ cells (shown by immunophenotypical and morphological criteria to be megakaryoblasts), which had been expanded ex vivo from CD34+ cells in chemically defined artificial serum, and 3) gel-filtered human peripheral blood platelets. Further, in an attempt to correlate the influence of these factors on cell proliferation and survival with activation of signal transduction pathways, we evaluated their effect on the phosphorylation of MAPK p42/44 and activation of PI-3K-AKT and JAK-STAT proteins in these various cell types. RESULTS Using serum-free liquid cultures, we found that only TPO and IL-6 protected CD34+ cells and megakaryocytes from undergoing apoptosis (decrease in annexin-V binding, PARP cleavage, and activation of caspase-3). Moreover, only TPO when used alone and IL-6 only when used in combination with TPO, stimulated the growth of human colony-forming unit-megakaryocytes (CFU-Meg) in semisolid serum-free medium. We also observed that while TPO efficiently activated various signaling pathways in CD34+ cells, megakaryocytes, and platelets (MAPK p42/44, PI-3K-AKT, STAT proteins), IL-6 stimulated phosphorylation of STAT-1, -3, and -5 proteins only in CD34+ cells and megakaryoblasts. To our surprise, none of the other gp130 protein-related cytokines tested (IL-11, LIF, CNTF, and OSM) activated these signaling pathways in CD34+ cells, megakaryoblasts, or platelets. CONCLUSIONS Our signal transduction studies explain why TPO, by simultaneously activating several signaling pathways, is the most potent megakaryopoietic regulator and why of all five gp130 protein-related cytokines tested, only IL-6, through activation of STAT proteins, plays a role in normal human megakaryopoiesis.
Collapse
Affiliation(s)
- Marcin Majka
- Stem Cell Biology Program at James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | | | | | | | | | | | | |
Collapse
|
12
|
Justicia C, Gabriel C, Planas AM. Activation of the JAK/STAT pathway following transient focal cerebral ischemia: signaling through Jak1 and Stat3 in astrocytes. Glia 2000; 30:253-70. [PMID: 10756075 DOI: 10.1002/(sici)1098-1136(200005)30:3<253::aid-glia5>3.0.co;2-o] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
JAK/STAT is one of the pathways bearing signals from the cell membrane to the nucleus in response to extracellular growth factors and cytokines. In the present study, we examined the cellular distribution of Jak1 and Stat3, and activation of the JAK/STAT pathway following transient focal cerebral ischemia in the rat. Jak1 was mainly seen in white matter astrocytes and in certain neurons. Notably, large pyramidal neurons of cortical layer V showed the highest neuronal Jak1 expression within cerebral cortex and, in addition, expressed Stat3 indicating that the JAK/STAT pathway is involved in signaling in the corticofugal projection system. Shortly following ischemia, Jak1 immunoreactive astrocytes located in the ipsilateral neighbouring white matter and ischemic cortex and striatum showed nuclear translocation of Stat3. These features were maintained in large reactive astrocytes that surrounded the infarct from 3 to 7 days. At these later times, the abundant reactive microglia/macrophages were strongly immunoreactive to Stat3 and, to a lesser extent, Jak1. Two main protein complexes showing DNA binding activity at the sis-inducible element site were found under basal conditions, followed by changes in this pattern following ischemia concomitant with neuronal cell loss and activation of glia. This study showed basal cerebral activity of JAK/STAT signaling pathway, involving Jak1 and Stat3 proteins, and selective activation following ischemia. It is suggested that the kinase activity of Jak1 mediates nuclear translocation of Stat3 in astrocytes, and that this signaling pathway is involved in the astroglial response to focal cerebral ischemia.
Collapse
Affiliation(s)
- C Justicia
- Departament de Farmacologia i Toxicologia, Institut d'Investigacions Biomèdiques de Barcelona, CSIC-IDIBAPS
| | | | | |
Collapse
|