1
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Branfield S, Washington AV, Manfredi B. Affordable Method for Hematocrit Determination in Murine Models. Curr Protoc 2024; 4:e1018. [PMID: 38578033 DOI: 10.1002/cpz1.1018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Hematocrit (Hct) is a powerful tool often used in a clinical setting for the diagnosis of blood conditions such as anemia. It is also used in the research field as a hematological parameter in both human and mouse models. Measuring Hct, however, involves the use of expensive standardized equipment (such as a CritSpin™ Microhematocrit Centrifuge). Here, we describe a novel, simple, and affordable method to determine the Hct in untreated wild-type (WT) mice and phenylhydrazine (PHZ)-induced anemic mice with reasonable accuracy, using a benchtop centrifuge commonly available in laboratories. Hct of murine samples processed with a benchtop centrifuge, when compared to the standardized method CritSpin™, showed comparable results. This approach for determining Hct of murine can prove useful to research laboratories that cannot afford specialized equipment for Hct studies. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Affordable Method for Hematocrit Determination in Murine Models Basic Protocol 2: Murine Sample Validation Support Protocol: Phenylhydrazine-induced anemia in wild-type (WT) mice.
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Affiliation(s)
- Siobhan Branfield
- Department of Biological Sciences, Oakland University, Rochester Hills, Michigan
| | - A Valance Washington
- Department of Biological Sciences, Oakland University, Rochester Hills, Michigan
| | - Barbara Manfredi
- Department of Biological Sciences, Oakland University, Rochester Hills, Michigan
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2
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Valance Washington A. Not so once upon a time. Res Pract Thromb Haemost 2024; 8:102288. [PMID: 38226340 PMCID: PMC10788298 DOI: 10.1016/j.rpth.2023.102288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024] Open
Abstract
This story reflects a personal narrative of a graduate student who experienced a disturbing incident during Mardi Gras in New Orleans, shedding light on the enduring issue of racism. The author's journey to graduate school and the challenges faced along the way provide context for the pivotal moment of racial discrimination. The narrative then shifts to the author's decision to prioritize education over anger, highlighting the sacrifices made to protect their future as a graduate student. The incident serves as a stark reminder that, despite personal achievements and aspirations, racial prejudice persists. In conclusion, the author calls for resilience and focus in the pursuit of personal goals while acknowledging the ongoing struggle against racism and other forms of discrimination in society. This personal story serves as a poignant reminder of the challenges faced by individuals and the need for continued efforts to combat systemic intolerance.
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3
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Bayrón-Marrero Z, Branfield S, Menéndez-Pérez J, Nieves-López B, Ospina L, Cantres-Rosario Y, Melendez LM, Hunter R, Gibson A, Maldonado-Martínez G, Washington AV. The Characterization and Evaluation of the Soluble Triggering Receptor Expressed on Myeloid Cells-like Transcript-1 in Stable Coronary Artery Disease. Int J Mol Sci 2023; 24:13632. [PMID: 37686440 PMCID: PMC10487797 DOI: 10.3390/ijms241713632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 08/27/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
Platelets play crucial roles in the development and progression of coronary artery disease (CAD). The triggering receptor expressed in myeloid cells-like transcript-1 (TLT-1) is stored in platelet α granules, and activated platelets release a soluble fragment (sTLT-1). We set out to better characterize the constituent amino acids of sTLT-1 and to evaluate sTLT-1 for use as a biomarker in patients with stable CAD. We evaluated sTLT-1 release using immunoprecipitation and mass spectrometry and employed statistical methods to retrospectively correlate sTLT-1 concentrations, utilizing ELISA in plasma samples from 1510 patients with documented stable CAD. We identified TLT-1 residues to 133 in platelet releasates. ADAM17 cuts TLT-1, suggesting that S136 is the C-terminal amino acid in sTLT-1. Our results revealed that for CAD patients, sTLT-1 levels did not differ significantly according to primary outcomes of death or major cardiac event; however, patients with left ventricular (LV) dysfunction had significantly lower plasma sTLT-1 levels as compared to those with normal LV function (981.62 ± 1141 pg/mL vs. 1247.48 ± 1589 pg/mL; p = 0.003). When patients were stratified based on sTLT-1 peak frequency distribution (544 pg/mL), a significant association with congestive heart failure was identified (OR = 2.94; 1.040-8.282; p = 0.042), which could be explained by LV dysfunction.
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Affiliation(s)
- Zaida Bayrón-Marrero
- Department of Biology, University of Puerto Rico–Rio Piedras, San Juan, PR 00936, USA; (Z.B.-M.); (S.B.); (J.M.-P.); (B.N.-L.); (L.O.)
| | - Siobhan Branfield
- Department of Biology, University of Puerto Rico–Rio Piedras, San Juan, PR 00936, USA; (Z.B.-M.); (S.B.); (J.M.-P.); (B.N.-L.); (L.O.)
- Department of Biology, Oakland University, Rochester Hills, MI 48309, USA
| | - Javier Menéndez-Pérez
- Department of Biology, University of Puerto Rico–Rio Piedras, San Juan, PR 00936, USA; (Z.B.-M.); (S.B.); (J.M.-P.); (B.N.-L.); (L.O.)
| | - Benjamín Nieves-López
- Department of Biology, University of Puerto Rico–Rio Piedras, San Juan, PR 00936, USA; (Z.B.-M.); (S.B.); (J.M.-P.); (B.N.-L.); (L.O.)
| | - Laura Ospina
- Department of Biology, University of Puerto Rico–Rio Piedras, San Juan, PR 00936, USA; (Z.B.-M.); (S.B.); (J.M.-P.); (B.N.-L.); (L.O.)
| | - Yadira Cantres-Rosario
- Translational Proteomics Center, Comprehensive Cancer Center, University of Puerto Rico, San Juan, PR 00936, USA; (Y.C.-R.); (L.M.M.)
| | - Loyda M. Melendez
- Translational Proteomics Center, Comprehensive Cancer Center, University of Puerto Rico, San Juan, PR 00936, USA; (Y.C.-R.); (L.M.M.)
- Department of Microbiology and Medical Zoology, University of Puerto Rico Medical Sciences Campus, San Juan, PR 00936, USA
| | - Robert Hunter
- Retroviral Research Center, Universidad Central del Caribe, Bayamón, PR 00960, USA;
| | - Angelia Gibson
- Division of Natural Sciences, Maryville College, Maryville, TN 37804, USA;
| | | | - A. Valance Washington
- Department of Biology, University of Puerto Rico–Rio Piedras, San Juan, PR 00936, USA; (Z.B.-M.); (S.B.); (J.M.-P.); (B.N.-L.); (L.O.)
- Department of Biology, Oakland University, Rochester Hills, MI 48309, USA
- William Beaumont School of Medicine, Oakland University, Rochester Hills, MI 48309, USA
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4
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Vilá LM, Nieves-Plaza M, Vales Torres X, Nieves B, Valance Washington A. Anti-Triggering Receptor Expressed on Myeloid Cells-Like Transcript-1 Antibodies in Systemic Lupus Erythematosus. Eur J Rheumatol 2023; 10:88-89. [PMID: 37249307 PMCID: PMC10544204 DOI: 10.5152/eurjrheum.2023.22051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 03/02/2023] [Indexed: 05/31/2023] Open
Affiliation(s)
- Luis M. Vilá
- Division of Rheumatology, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
| | | | - Xariana Vales Torres
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico
| | - Benjamín Nieves
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico
| | - A. Valance Washington
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico
- Department of Biological Sciences, Oakland University, Rochester, Michigan, USA
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5
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Abstract
Receptors are important pharmacological targets on cells. The Triggering Receptor Expressed on Myeloid Cells (TREM) - Like Transcript - 1 is an abundant, yet little understood, platelet receptor. It is a single Ig domain containing receptor isolated in the α-granules of resting platelets and brought to the platelet surface upon activation. On platelets, the integrin αIIbβ3 is the major receptor having roughly 80,000 copies. αIIbβ3 is a heterodimeric multidomain structure that mediates platelet aggregation through its interaction with the plasma protein fibrinogen. Anti-platelet drugs have successfully targeted αIIbβ3 to control thrombosis. Like αIIbβ3, TLT-1 also binds fibrinogen, making its role in platelet function somewhat obscure. In this review, we highlight the known structural features of TLT-1 and present the challenges of understanding TLT-1 function. In our analysis of the dynamics of the platelet surface after activation we propose a model in which TLT-1 supports αIIbβ3 function as a mechanoreceptor that may direct platelets toward immune function.
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Affiliation(s)
- Siobhan Branfield
- , Department of Biology, University of Puerto Rico- Rio Piedras- Molecular Science Research Center, San Juan, Puerto Rico
| | - A Valance Washington
- , Department of Biology, University of Puerto Rico- Rio Piedras- Molecular Science Research Center, San Juan, Puerto Rico
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6
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Branfield S, Washington AV. Control the platelets, control the disease: A novel cystic fibrosis hypothesis. J Thromb Haemost 2020; 18:1531-1534. [PMID: 32468670 PMCID: PMC7872297 DOI: 10.1111/jth.14868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 04/16/2020] [Accepted: 04/20/2020] [Indexed: 12/29/2022]
Affiliation(s)
- Siobhan Branfield
- Department of Biology, University of Puerto Rico- Rio Piedras- Molecular Science Research Center, San Juan, Puerto Rico
| | - A Valance Washington
- Department of Biology, University of Puerto Rico- Rio Piedras- Molecular Science Research Center, San Juan, Puerto Rico
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7
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Schmoker AM, Perez Pearson LM, Cruz C, Colon Flores LG, Branfeild S, Pagán Torres FD, Fonseca K, Cantres YM, Salgado Ramirez CA, Melendez LM, Ballif BA, Washington AV. Defining the TLT-1 interactome from resting and activated human platelets. J Proteomics 2020; 215:103638. [PMID: 31923473 PMCID: PMC7044047 DOI: 10.1016/j.jprot.2020.103638] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/03/2020] [Accepted: 01/05/2020] [Indexed: 12/14/2022]
Abstract
The triggering receptor expressed on myeloid cells (TREM) protein family forms a class of type I transmembrane proteins expressed in immune cells that play important roles in innate and adaptive immune responses. The TREM family member TREM-like transcript 1 (TLT-1, also TREML1) is expressed in megakaryocytes and packaged into platelet granules. TLT-1 binds fibrinogen and plays a role in bleeding initiated by inflammatory insults. Here, we describe a proteomics screen that maps the TLT-1 interactome in resting and activated human platelets. Several identified TLT-1 interactors are involved in cell adhesion and migration, as well as platelet activation. Select interactors, including β3-integrin, RACK1, GRB2, and Rabs 5A, 7, and 11A, were additionally characterized in co-immunoprecipitation/immunoblotting experiments. Finally, several phosphorylation sites were found on immunoprecipitated TLT-1, including Thr280, a novel, regulated site on a conserved residue near the TLT-1 ITIM regulatory sequence. SIGNIFICANCE: Platelet function relies on the secretion of active molecules from intracellular vesicles, or granules, which contain soluble and membrane-bound proteins that are essential for platelet aggregation, coagulation reactions, and pathogen defense mechanisms. TLT-1 is sequestered in α-granules and transported to the plasma membrane, where it plays a unique role in hemostasis after inflammatory insults. Despite the known importance of TLT-1 in platelet biology, our knowledge of TLT-1 mechanistic signaling is limited. This study defines the TLT-1 interactome in resting and active human platelets, identifying several novel TLT-1 interactors, as well as TLT-1 phosphorylation sites, all with likely signaling implications in platelet aggregation dynamics.
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Affiliation(s)
- Anna M Schmoker
- Department of Biology, University of Vermont, 109 Carrigan Drive, 120A Marsh Life Sciences, Burlington, VT 05405, USA.
| | - Leishla M Perez Pearson
- Department of Biology, University of Vermont, 109 Carrigan Drive, 120A Marsh Life Sciences, Burlington, VT 05405, USA; Department of Biology, University of Puerto Rico-Río Piedras, Department of Biology, San Juan, PR, USA
| | - Claudia Cruz
- Department of Biology, University of Vermont, 109 Carrigan Drive, 120A Marsh Life Sciences, Burlington, VT 05405, USA; Department of Biology, University of Puerto Rico-Río Piedras, Department of Biology, San Juan, PR, USA
| | - Luis G Colon Flores
- Department of Biology, University of Puerto Rico-Río Piedras, Department of Biology, San Juan, PR, USA
| | - Siobhan Branfeild
- Department of Biology, University of Puerto Rico-Río Piedras, Department of Biology, San Juan, PR, USA
| | - Fabiola D Pagán Torres
- Department of Biology, University of Vermont, 109 Carrigan Drive, 120A Marsh Life Sciences, Burlington, VT 05405, USA
| | - Karmen Fonseca
- Department of Biology, University of Vermont, 109 Carrigan Drive, 120A Marsh Life Sciences, Burlington, VT 05405, USA
| | - Yadira M Cantres
- Translational Proteomics Center, Comprehensive Cancer Center, University of Puerto Rico, Medical Sciences Campus, San Juan, PR, USA
| | - Carla A Salgado Ramirez
- Translational Proteomics Center, Comprehensive Cancer Center, University of Puerto Rico, Medical Sciences Campus, San Juan, PR, USA
| | - Loyda M Melendez
- Department of Microbiology and Medical Zoology, University of Puerto Rico, Medical Sciences Campus, San Juan, PR, USA; Translational Proteomics Center, Comprehensive Cancer Center, University of Puerto Rico, Medical Sciences Campus, San Juan, PR, USA
| | - Bryan A Ballif
- Department of Biology, University of Vermont, 109 Carrigan Drive, 120A Marsh Life Sciences, Burlington, VT 05405, USA.
| | - A Valance Washington
- Department of Biology, University of Puerto Rico-Río Piedras, Department of Biology, San Juan, PR, USA.
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8
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Hernandez‐Matias L, Pérez‐Donato L, Román PL, Laureano‐Torres F, Calzada‐Jorge N, Mendoza S, Washington AV, Borrero M. An exploratory study comparing students' science identity perceptions derived from a hands-on research and nonresearch-based summer learning experience. Biochem Mol Biol Educ 2020; 48:134-142. [PMID: 31724798 PMCID: PMC7079089 DOI: 10.1002/bmb.21314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/15/2019] [Accepted: 10/18/2019] [Indexed: 06/10/2023]
Abstract
Although multiple efforts have been initiated to increase students' science proficiency scores, most of the schools in the United States do not reach the expected student academic performance. This study addresses the impact of a one-week summer scientific learning experience on students that worked with experimental procedures and students that did not. We describe and evaluate these two different interventions to explore what components influence high school students' perception of their scientific competence, performance, and recognition, using science identity as an analytical lens. Science identity score was increased at the end of both interventions. Interestingly, science identity change index was higher for the group that did not work with experimental procedures. Although this group did not perform any hands-on experiments, they report, through reflexive diaries and interviews that working with CRISPR-Cas9 models, being in a research laboratory, and seeing the instrumentation made them feel like scientists. Regarding science competence, both groups report exponential learning gains, although the group that performed the experiments reports more difficulties. Both groups report that mentorship was key in their competence and performance development. These findings suggest that our one-week scientific learning programs influence participants' perception of scientific competence and performance and create an opportunity to develop further studies on short scientific learning experiences using models and active learning activities.
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Affiliation(s)
- Liz Hernandez‐Matias
- Biology DepartmentUniversity of Puerto Rico, Río Piedras CampusSan JuanPuerto Rico
| | - Lizmar Pérez‐Donato
- Biology DepartmentUniversity of Puerto Rico, Río Piedras CampusSan JuanPuerto Rico
| | - Pablo Llerandi Román
- Puerto Rico‐Louis Stokes Alliance for Minority ParticipationCentro de Recursos para Ciencias e Ingeniería Universidad de Puerto RicoSan JuanPuerto Rico
| | | | | | | | | | - Michelle Borrero
- Biology DepartmentUniversity of Puerto Rico, Río Piedras CampusSan JuanPuerto Rico
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9
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Washington AV, Esponda O, Gibson A. Platelet biology of the rapidly failing lung. Br J Haematol 2019; 188:641-651. [PMID: 31696941 DOI: 10.1111/bjh.16315] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/23/2019] [Accepted: 08/24/2019] [Indexed: 12/15/2022]
Abstract
Acute respiratory distress syndrome (ARDS) is characterized by a rapid-onset respiratory failure with a mortality rate of approximately 40%. This physiologic inflammatory process is mediated by disruption of the alveolar-vascular interface, leading to pulmonary oedema and impaired oxygen exchange, which often warrants mechanical ventilation to increase survival in the acute setting. One of the least understood aspects of ARDS is the role of the platelets in this process. Platelets, which protect vascular integrity, play a pivotal role in the progression and resolution of ARDS. The recent substantiation of the age-old theory that megakaryocytes are found in the lungs has rejuvenated interest in and raised new questions about the importance of platelets for pulmonary function. In addition to primary haemostasis, platelets provide a myriad of inflammatory functions that are poised to aid the innate immune system. This review focuses on the evidence for regulatory roles of platelets in pulmonary inflammation, with an emphasis on two receptors, CLEC-2 and TLT-1. Studies of these receptors identify novel pathways through which platelets may regulate vascular integrity and inflammation in the lungs, thereby influencing the development of ARDS.
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Affiliation(s)
- A Valance Washington
- Department of Biology, Molecular Science Research Center, University of Puerto Rico-Rio Piedras, San Juan, PR, USA
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10
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Campbell RA, Schwertz H, Hottz ED, Rowley JW, Manne BK, Washington AV, Hunter-Mellado R, Tolley ND, Christensen M, Eustes AS, Montenont E, Bhatlekar S, Ventrone CH, Kirkpatrick BD, Pierce KK, Whitehead SS, Diehl SA, Bray PF, Zimmerman GA, Kosaka Y, Bozza PT, Bozza FA, Weyrich AS, Rondina MT. Human megakaryocytes possess intrinsic antiviral immunity through regulated induction of IFITM3. Blood 2019; 133:2013-2026. [PMID: 30723081 PMCID: PMC6509546 DOI: 10.1182/blood-2018-09-873984] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 01/22/2019] [Indexed: 02/07/2023] Open
Abstract
Evolving evidence indicates that platelets and megakaryocytes (MKs) have unexpected activities in inflammation and infection; whether viral infections upregulate biologically active, antiviral immune genes in platelets and MKs is unknown, however. We examined antiviral immune genes in these cells in dengue and influenza infections, viruses that are global public health threats. Using complementary biochemical, pharmacological, and genetic approaches, we examined the regulation and function of interferon-induced transmembrane protein 3 (IFITM3), an antiviral immune effector gene not previously studied in human platelets and MKs. IFITM3 was markedly upregulated in platelets isolated from patients during clinical influenza and dengue virus (DENV) infections. Lower IFITM3 expression in platelets correlated with increased illness severity and mortality in patients. Administering a live, attenuated DENV vaccine to healthy subjects significantly increased platelet IFITM3 expression. Infecting human MKs with DENV selectively increased type I interferons and IFITM3. Overexpression of IFITM3 in MKs was sufficient to prevent DENV infection. In naturally occurring, genetic loss-of-function studies, MKs from healthy subjects harboring a homozygous mutation in IFITM3 (rs12252-C, a common single-nucleotide polymorphism in areas of the world where DENV is endemic) were significantly more susceptible to DENV infection. DENV-induced MK secretion of interferons prevented infection of bystander MKs and hematopoietic stem cells. Thus, viral infections upregulate IFITM3 in human platelets and MKs, and IFITM3 expression is associated with adverse clinical outcomes. These observations establish, for the first time, that human MKs possess antiviral functions, preventing DENV infection of MKs and hematopoietic stem cells after local immune signaling.
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Affiliation(s)
- Robert A Campbell
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Department of Internal Medicine and
| | - Hansjorg Schwertz
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Department of Internal Medicine and
- Rocky Mountain Center for Occupational and Environmental Health, University of Utah, Salt Lake City, UT
| | - Eugenio D Hottz
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Instituto Nacional de Infectologia Evandro Chagas and
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Jesse W Rowley
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Department of Internal Medicine and
| | | | - A Valance Washington
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
- Department of Internal Medicine, Universidad Central del Caribe, Bayamón, Puerto Rico
| | - Robert Hunter-Mellado
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
- Department of Internal Medicine, Universidad Central del Caribe, Bayamón, Puerto Rico
| | - Neal D Tolley
- University of Utah Molecular Medicine Program, Salt Lake City, UT
| | | | - Alicia S Eustes
- University of Utah Molecular Medicine Program, Salt Lake City, UT
| | - Emilie Montenont
- University of Utah Molecular Medicine Program, Salt Lake City, UT
| | - Seema Bhatlekar
- University of Utah Molecular Medicine Program, Salt Lake City, UT
| | - Cassandra H Ventrone
- Vaccine Testing Center, Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, VT
| | - Beth D Kirkpatrick
- Vaccine Testing Center, Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, VT
| | - Kristen K Pierce
- Vaccine Testing Center, Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, VT
| | - Stephen S Whitehead
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - Sean A Diehl
- Vaccine Testing Center, Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, VT
| | - Paul F Bray
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Department of Internal Medicine and
| | - Guy A Zimmerman
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Department of Internal Medicine and
| | - Yasuhiro Kosaka
- University of Utah Molecular Medicine Program, Salt Lake City, UT
| | - Patricia T Bozza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Fernando A Bozza
- Instituto Nacional de Infectologia Evandro Chagas and
- Instituto D'Or de Pesquisa e Ensino, Rio de Janeiro, Brazil; and
| | - Andrew S Weyrich
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Department of Internal Medicine and
| | - Matthew T Rondina
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Department of Internal Medicine and
- Department of Internal Medicine, George E. Wahlen Veterans Affairs Medical Center and Geriatric Research, Education, and Clinical Center, Salt Lake City, UT
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11
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Morales-Ortíz J, Deal V, Reyes F, Maldonado-Martínez G, Ledesma N, Staback F, Croft C, Pacheco A, Ortiz-Zuazaga H, Yost CC, Rowley JW, Madera B, John AS, Chen J, Lopez J, Rondina MT, Hunter R, Gibson A, Washington AV. Platelet-derived TLT-1 is a prognostic indicator in ALI/ARDS and prevents tissue damage in the lungs in a mouse model. Blood 2018; 132:2495-2505. [PMID: 30282800 PMCID: PMC6284217 DOI: 10.1182/blood-2018-03-841593] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 09/14/2018] [Indexed: 02/06/2023] Open
Abstract
Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) affect >200 000 individuals yearly with a 40% mortality rate. Although platelets are implicated in the progression of ALI/ARDS, their exact role remains undefined. Triggering receptor expressed in myeloid cells (TREM)-like transcript 1 (TLT-1) is found on platelets, binds fibrinogen, and mediates clot formation. We hypothesized that platelets use TLT-1 to manage the progression of ALI/ARDS. Here we retrospectively measure plasma levels of soluble TLT-1 (sTLT-1) from the ARDS Network clinical trial and show that patients whose sTLT-1 levels were >1200 pg/mL had nearly twice the mortality risk as those with <1200 pg/mL (P < .001). After correcting for confounding factors such as creatinine levels, Acute Physiology And Chronic Health Evaluation III scores, age, platelet counts, and ventilation volume, sTLT-1 remains significant, suggesting that sTLT-1 is an independent prognostic factor (P < .0001). These data point to a role for TLT-1 during the progression of ALI/ARDS. We use a murine lipopolysaccharide-induced ALI model and demonstrate increased alveolar bleeding, aberrant neutrophil transmigration and accumulation associated with decreased fibrinogen deposition, and increased pulmonary tissue damage in the absence of TLT-1. The loss of TLT-1 resulted in an increased proportion of platelet-neutrophil conjugates (43.73 ± 24.75% vs 8.92 ± 2.4% in wild-type mice), which correlated with increased neutrophil death. Infusion of sTLT-1 restores normal fibrinogen deposition and reduces pulmonary hemorrhage by 40% (P ≤ .001) and tissue damage by 25% (P ≤ .001) in vivo. Our findings suggest that TLT-1 uses fibrinogen to govern the transition between inflammation and hemostasis and facilitate controlled leukocyte transmigration during the progression of ARDS.
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Affiliation(s)
| | - Victoria Deal
- Division of Natural Sciences, Maryville College, Maryville, TN
| | - Fiorella Reyes
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
| | | | - Nahomy Ledesma
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
| | - Franklin Staback
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
| | - Cheyanne Croft
- Division of Natural Sciences, Maryville College, Maryville, TN
| | - Amanda Pacheco
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
| | - Humberto Ortiz-Zuazaga
- Department of Computer Science, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
| | - C Christian Yost
- Department of Pediatrics/Neonatology and Molecular Medicine Program and
| | - Jesse W Rowley
- Department of Internal Medicine and Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, UT
| | - Bismark Madera
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
| | - Alex St John
- Bloodworks Northwest Research Institute, Seattle, WA; and
| | - Junmei Chen
- Bloodworks Northwest Research Institute, Seattle, WA; and
| | - Jose Lopez
- Bloodworks Northwest Research Institute, Seattle, WA; and
| | - Matthew T Rondina
- Department of Internal Medicine and Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, UT
- Geriatric Research, Education and Clinical Center, Department of Medicine, George E. Wahlen VA Medical Center, Salt Lake City, UT
| | - Robert Hunter
- Retroviral Research Center, Universidad Central del Caribe, Bayamón, Puerto Rico
| | - Angelia Gibson
- Division of Natural Sciences, Maryville College, Maryville, TN
| | - A Valance Washington
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
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12
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Vázquez-Otero I, Rodríguez-Navedo Y, Vilá-Rivera K, Nieves-Plaza M, Morales-Ortiz J, Washington AV, Vilá LM. Association of soluble TREM-like transcript-1 with clinical features and patient reported outcomes in systemic lupus erythematosus. Eur J Rheumatol 2018; 5:244-248. [PMID: 30308137 PMCID: PMC6267757 DOI: 10.5152/eurjrheum.2018.18074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/27/2018] [Indexed: 01/04/2023] Open
Abstract
OBJECTIVE The soluble triggering receptor expressed on myeloid cells (TREM-1)-like transcript 1 (sTLT-1) has a modulatory effect on the activation of TREM-1. We compared plasma sTLT-1 levels between patients with systemic lupus erythematosus (SLE) and healthy individuals and determined the association between sTLT-1 levels and clinical features and patient-reported outcomes (PROs) among patients with lupus. METHODS An unmatched case-control study was conducted in 46 patients with SLE and 28 healthy subjects. sTLT-1 plasma levels were determined using enzyme-linked immunosorbent assay. Demographic factors, SLE manifestations, comorbidities, pharmacologic profile, disease activity (per SLAM-R), damage accrual, and PROs (as per Lupus Patient-Reported Outcome [LupusPRO]) were studied. RESULTS Patients with SLE were found to have lower sTLT-1 levels compared with healthy individuals (9.0±7.2 vs. 18.6±22.3 pg/mL, p=0.008). Among patients with SLE, higher sTLT-1 levels were found in those taking corticosteroids (11.1±8.8 vs. 6.9±4.6 pg/mL, p=0.014). Significant correlations were found for the cognition (r=-0.442, p=0.027) and desires/goals (r=0.435, p=0.030) domains of LupusPRO. A tendency was observed between sTLT-1 levels and the SLAM-R (r=-0.278, p=0.064) and the lupus symptoms (r=-0.388, p=0.055) and physical health (r=-0.382, p=0.060) domains of LupusPRO. CONCLUSION Compared with healthy individuals, sTLT-1 levels were significantly lower in patients with SLE. Among patients with SLE, correlations were observed for some domains of LupusPRO. Given that sTLT-1 has anti-inflammatory properties, the deficiency of this protein could play an important role in the pathogenesis of SLE.
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Affiliation(s)
- Ileana Vázquez-Otero
- Division of Rheumatology, Department of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
| | - Yerania Rodríguez-Navedo
- Division of Rheumatology, Department of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
| | - Karina Vilá-Rivera
- Division of Rheumatology, Department of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
| | - Mariely Nieves-Plaza
- Division of Rheumatology, Department of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
| | - Jessica Morales-Ortiz
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico
| | - A Valance Washington
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico
| | - Luis M Vilá
- Division of Rheumatology, Department of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
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13
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Manfredi B, Morales-Ortíz J, Díaz-Díaz LM, Hernandez-Matias L, Barreto-Vázquez D, Menéndez-Pérez J, Rodríguez-Cordero JA, Villalobos-Santos JC, Santiago-Rivera E, Rivera-Dompenciel A, Lozada-Delgado EL, Kuchibhotla M, Carrasquillo-Carrión K, Roche-Lima A, Washington AV. The Characterization of Monoclonal Antibodies to Mouse TLT-1 Suggests That TLT-1 Plays a Role in Wound Healing. Monoclon Antib Immunodiagn Immunother 2018; 37:78-86. [PMID: 29708866 DOI: 10.1089/mab.2017.0063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Platelets play a vital role in hemostasis and inflammation. The membrane receptor TREM-like transcript-1 (TLT-1) is involved in platelet aggregation, bleeding, and inflammation, and it is localized in the α-granules of platelets. Upon platelet activation, TLT-1 is released from α-granules both in its transmembrane form and as a soluble fragment (sTLT-1). Higher levels of sTLT-1 have been detected in the plasma of patients with acute inflammation or sepsis, suggesting an important role for TLT-1 during inflammation. However, the roles of TLT-1 in hemostasis and inflammation are not well understood. We are developing the mouse model of TLT-1 to mechanistically test clinical associations of TLT-1 in health and disease. To facilitate our studies, monoclonal murine TLT-1 (mTLT-1) antibodies were produced by the immunization of a rabbit using the negatively charged region of the mTLT-1 extracellular domain 122PPVPGPREGEEAEDEK139. In the present study, we demonstrate that two selected clones, 4.6 and 4.8, are suitable for the detection of mTLT-1 by western blot, immunoprecipitation, immunofluorescent staining, flow cytometry and inhibit platelet aggregation in aggregometry assays. In addition, we found that the topical administration of clone 4.8 delayed the wound healing process in an experimental burn model. These results suggest that TLT-1 plays an important role in wound healing and because both clones specifically detect mTLT-1, they are suitable to further develop TLT-1 based models of inflammation and hemostasis in vivo.
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Affiliation(s)
- Barbara Manfredi
- 1 Biology Department, University of Puerto Rico , San Juan, Puerto Rico
| | | | | | | | | | | | | | | | | | | | | | | | - Kelvin Carrasquillo-Carrión
- 2 ARL Lab-Bioinformatics and Health Informatics, Recinto Central Medico, University of Puerto Rico , San Juan, Puerto Rico
| | - Abiel Roche-Lima
- 2 ARL Lab-Bioinformatics and Health Informatics, Recinto Central Medico, University of Puerto Rico , San Juan, Puerto Rico
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14
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Morales-Ortíz J, Rondina MT, Brown SM, Grissom C, Washington AV. High Levels of Soluble Triggering Receptor Expressed on Myeloid Cells-Like Transcript (TLT)-1 Are Associated With Acute Respiratory Distress Syndrome. Clin Appl Thromb Hemost 2018; 24:1122-1127. [PMID: 29758998 PMCID: PMC6219757 DOI: 10.1177/1076029618774149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We have previously demonstrated that elevated levels of soluble triggering receptor expressed on myeloid cells-like transcript 1 (sTLT-1) modulate sepsis-induced inflammation and positively correlate with disseminated intravascular coagulation (DIC). Here, we evaluate the clinical implications of plasma sTLT-1 in acute respiratory distress syndrome (ARDS), which is common in sepsis patients. Soluble TLT-1 levels in the plasma of ARDS patients (n = 20) were determined by slot blot analysis and were compared with clinical parameters to identify significant associations. For comparisons to ARDS, we also measured sTLT-1 levels in matched healthy controls (n = 20). Of the 20 plasma samples evaluated from patients with ARDS, 60% were diagnosed with sepsis and 40% were diagnosed with septic shock. The white blood cells (WBCs) of patients with ARDS were found to be significantly elevated over healthy controls with a mean of 13 k/µL over 6.2 k/µL, respectively. The mean plasma levels of sTLT-1 were 148.4 pg/mL ± 16.52 in the patient cohort and 92.45 pg/mL ± 17.12 in the control group ( P = .02). No statistically significant correlations were found between plasma levels of sTLT-1 and WBCs, sepsis, septic shock or acute physiologic, and chronic health evaluation II scores. A statistically significant inverse correlation (r2 = .25, P < .05) was found between plasma sTLT-1 and peripheral platelet counts in patients with ARDS. Increased levels of sTLT-1 in ARDS patients suggest that TLT-1 may mediate the pathobiology of ARDS. Moreover, our data are the first to demonstrate a specific platelet marker in the development of ARDS due to sepsis.
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Affiliation(s)
- Jessica Morales-Ortíz
- 1 Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
| | - Matthew T Rondina
- 2 Laboratory of Anatomy and Cell Biology, Molecular Medicine Program and Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA.,3 Department of Medicine and the Molecular Medicine Program, the University of Utah Health Sciences Center, Salt Lake City, UT, USA.,4 George E. Wahlen VAMC GRECC, Salt Lake City, UT, USA
| | - Samuel M Brown
- 5 Pulmonary and Critical Care Medicine, Intermountain Medical Center, Murray, UT, USA.,6 Pulmonary and Critical Care Medicine, University of Utah, Salt Lake City, UT, USA
| | - Colin Grissom
- 5 Pulmonary and Critical Care Medicine, Intermountain Medical Center, Murray, UT, USA.,6 Pulmonary and Critical Care Medicine, University of Utah, Salt Lake City, UT, USA
| | - A Valance Washington
- 1 Department of Biology, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
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15
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Kucheryavykh LY, Dávila-Rodríguez J, Rivera-Aponte DE, Zueva LV, Washington AV, Sanabria P, Inyushin MY. Platelets are responsible for the accumulation of β-amyloid in blood clots inside and around blood vessels in mouse brain after thrombosis. Brain Res Bull 2016; 128:98-105. [PMID: 27908798 DOI: 10.1016/j.brainresbull.2016.11.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Platelets contain beta-amyloid precursor protein (APP) as well as Aβ peptide (Aβ) that can be released upon activation. During thrombosis, platelets are concentrated in clots and activated. METHODS We used in vivo fluorescent analysis and electron microscopy in mice to determine to what degree platelets are concentrated in clots. We used immunostaining to visualize Aβ after photothrombosis in mouse brains. RESULTS Both in vivo results and electron microscopy revealed that platelets were 300-500 times more concentrated in clots than in non-clotted blood. After thrombosis in control mice, but not in thrombocytopenic animals, Aβ immunofluorescence was present inside blood vessels in the visual cortex and around capillaries in the entorhinal cortex. CONCLUSION The increased concentration of platelets allows enhanced release of Aβ during thrombosis, suggesting an additional source of Aβ in the brains of Alzheimer's patients that may arise if frequent micro-thrombosis events occur in their brains.
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Affiliation(s)
- Lilia Y Kucheryavykh
- Department of Biochemistry, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
| | - Josué Dávila-Rodríguez
- School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
| | - David E Rivera-Aponte
- Department of Biochemistry, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
| | - Lidia V Zueva
- Department of Physics, University of Puerto Rico Rio Piedras, San Juan, PR 00936, USA.
| | - A Valance Washington
- Department of Anatomy, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA; The Department of Biology, University of Puerto Rico Rio Piedras, San Juan, PR 00936, USA.
| | - Priscilla Sanabria
- Department of Physiology, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
| | - Mikhail Y Inyushin
- Department of Physiology, School of Medicine, Universidad Central del Caribe, Bayamon, PR 00960-6032, (P.O. Box 60327), USA.
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16
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Esponda OL, Hunter R, Del Río JRR, Washington AV. Levels of soluble TREM-like transcript 1 in patients presenting to the emergency department with chest pain. Clin Appl Thromb Hemost 2014; 21:30-4. [PMID: 25147325 DOI: 10.1177/1076029614547298] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE Recent studies suggest that the soluble triggering receptor expressed on myeloid cells-like transcript 1 (sTLT-1) facilitate atherothrombosis. Therefore, we evaluated sTLT-1 as a functional measure of atherothrombosis in acute coronary syndrome (ACS). METHODS Levels of sTLT-1 were determined by enzyme-linked immunosorbent assay on plasma from patients with potential ACS and compared with an age-matched control group with similar risk factors for cardiovascular disease. RESULTS Of 53 patients enrolled, 19 patients were undergoing ACS (15 unstable angina, 2 non-ST-segment elevated myocardial infarction, and 2 ST-segment elevated myocardial infarction), 5 patients were found with noncardiac chest pain, and 29 were in the control group. The mean plasma sTLT-1 values in the ACS group were 4.644 ng/mL ± 1.277 standard error of the mean (SEM), in the noncardiac chest pain group were 0.708 ng/mL ± 0.427 SEM, and in the control group were 1.007 ng/mL ± 0.098 SEM. CONCLUSION A statistically significant difference exists between patients experiencing cardiogenic chest pain versus controls (P < .05), suggesting sTLT-1 as a potential tool for understanding atherothrombosis in ACS.
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Affiliation(s)
- Omar L Esponda
- Department of Internal Medicine, Hospital Universitario Dr Ramón Ruiz Arnau, Universidad Central del Caribe, Bayamón, PR, USA
| | - Robert Hunter
- Department of Internal Medicine, Hospital Universitario Dr Ramón Ruiz Arnau, Universidad Central del Caribe, Bayamón, PR, USA Laboratory of Anatomy and Cell Biology, Hospital HIMA San Pablo, Bayamón, PR, USA
| | - José R Rivera Del Río
- Department of Internal Medicine, Hospital Universitario Dr Ramón Ruiz Arnau, Universidad Central del Caribe, Bayamón, PR, USA Laboratory of Anatomy and Cell Biology, Hospital HIMA San Pablo, Bayamón, PR, USA
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17
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Ramos G, Loperena Y, Ortiz G, Reyes F, Szeto A, Vera J, Velez J, Morales J, Morrero D, Castillo L, Dharmawardhane S, Melendez E, Washington AV. The addition of a pregnenolone pendant group enhances the anticancer properties of titanocene dichloride in a mcf-7 xenograft model. Anticancer Res 2014; 34:1609-1615. [PMID: 24692689 PMCID: PMC4053690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
BACKGROUND/AIM Titanocene dichloride held great promise as a chemotherapeutic compound in pre-clinical studies. However, subsequent clinical trials revealed hepatoxicity and nephrotoxicity, which limited its use in clinical applications. Therefore, we used steroid pendant groups to improve the targeting of titanocene in MCF-7 breast cancer cells, and demonstrated a 10-fold lower effective dose compared to titanocene in in vitro assays. The aim of the present study was to test the efficacy of a titanocene functionalized with pregnenolone (Ti-Preg) in an in vivo breast cancer model. MATERIALS AND METHODS Xenografts from the MCF7 breast cancer cell line were implanted into athymic nu/nu mice to evaluate the potential of Ti-Preg as an anti-breast cancer agent. RESULTS Ti-Preg demonstrated significant inhibition of MCF-7 tumor growth when compared to vehicle and to titanocene controls. CONCLUSION Our findings demonstrate the potential of steroid pendent groups for targeting chemotherapeutics to steroid hormone-dependent cancer.
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Affiliation(s)
- Gladiany Ramos
- Department of Biology, University of Puerto Rico - Reciento Rio Piedras, PO Box 23360, San Juan, Puerto Rico 00931.
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18
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Gonzalez M, Reyes F, Marrero D, Washington AV. Abstract 463: TLT-1 Deficiency Affects Hypercholesterolemia and Progression of the Atherosclerotic Plaque in Apoe Null Mice. Arterioscler Thromb Vasc Biol 2013. [DOI: 10.1161/atvb.33.suppl_1.a463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Platelet activation at sites of inflammation triggers the secretion of molecules that induce the transition of atherosclerosis from fatty streak to an acute disease, featuring an increased vulnerability of the atherosclerotic lesion that results in plaque rupture and thrombosis. TLT-1 (Triggering Receptor Expressed in Myeloid cells (TREM)-like transcript-1) is a molecule exclusively found in the α-granules of megakarocytes and platelets and has a demonstrated effect in inflammatory responses. Upon platelet activation, TLT-1 is moved to the platelet surface, while its soluble form, s-TLT-1, is secreted and detected in serum. Studies using the C57Bl/6
treml1
-
/-
mouse demonstrated a predisposition to hemorrhage after an acute inflammatory challenge suggesting that TLT-1 may be a key regulatory molecule in the interface between hemostatic and inflammatory mechanisms. Because we have found that sTLT-1 levels are significantly elevated in apoE mice when compared to wild type, we hypothesized that TLT-1 may be playing an important role in the progression of atherosclerosis. To address this possibility, we generated apoE
-
/-
/
treml1
-
/-
double knockout mice [DN]. Assessment of lesions after 4 weeks high-fat diet (HFD) demonstrated that at early stages, TLT-1 deficiency accelerates fatty streak formation. After 20 weeks on HFD, lesions in both apoE
-
/-
and [DN] mice progressed to an advance fibrous plaque stage. Although their lesion sizes were not substantially different, lesion compositions were. The mechanistic basis of these differences appears to be that the [DN] mice have significantly higher cholesterol levels when compared to apoE
-
/-
mice. The increased cholesterol levels extend to the
treml1
-/-
mouse when compared to wild type mice at 4 weeks on HFD, this difference, however, gradually subsides as wild type mice cholesterol levels increase over 20 weeks. Interestingly, cholesterol levels in 50 week old mice on chow diet revealed minimal differences between test and control mice suggesting the higher cholesterol levels are related to increased dietary intake. Our work defines a surprising role for TLT-1 in the regulation of serum cholesterol levels during atherogenesis.
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Affiliation(s)
- Marieli Gonzalez
- Dept of Anatomy, Cell and Molecular Biology, Universidad Central del Caribe, Bayamon, Puerto Rico
| | - Fiorella Reyes
- Dept of Anatomy, Cell and Molecular Biology, Universidad Central del Caribe, Bayamon, Puerto Rico
| | - Deborah Marrero
- Dept of Anatomy, Cell and Molecular Biology, Universidad Central del Caribe, Bayamon, Puerto Rico
| | - A V Washington
- Dept of Anatomy, Cell and Molecular Biology, Universidad Central del Caribe, Bayamon, Puerto Rico
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19
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Gonzalez M, Reyes F, Marrero D, Washington AV. Abstract 309: The Role of TLT-1 in Atherosclerosis Lesion Formation. Arterioscler Thromb Vasc Biol 2012. [DOI: 10.1161/atvb.32.suppl_1.a309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Platelets have a well documented role in atherosclerotic lesion formation. They play a role from the initiation of the lesion to final occlusion of an atherosclerotic vessel. While it is known that regulating aggregation is important to control the thrombus that leads to occlusion, the platelet’s role in promoting lesion formation is less defined. Molecules stored in the platelet a-granules such as p-selectin and cytokines, which promote the inflammatory side of platelet function, have been shown to affect lesion progression. These molecules, however, only provide an outline of the platelet function during this process. and thus our understanding of how platelets participate in the progression of atherosclerosis remains a gap in our knowledge. The Triggering Receptor Expressed Myeloid cells (TREM)-like transcript (TLT)-1 is a receptor found in the α-granules of both megakaryocytes and platelets. Antibodies to TLT-1 have been shown to inhibit platelet aggregation and accordingly studies using the treml1
-/-
mouse have demonstrated that TLT-1 null mice have reduced platelet aggregation and extended tail-bleeding times. Subsequent studies using the treml1
-/-
mouse demonstrated a predisposition to hemorrhage derived from an inflammatory challenge suggesting that TLT-1 may be a key regulatory molecule in the interface between hemostatic and inflammatory mechanisms. Additionally, apoE null mice have significantly higher levels of the soluble form of TLT-1 (sTLT-1) in their plasma compared to wild type mice suggesting that sTLT-1 may play a role in the progression of atherosclerotic lesions. Therefore, we hypothesized that removal of TLT-1 receptor will delay the formation of atherosclerotic lesions in an apoE deficient genetic background. To address our hypothesis, we have created an apoE/treml1 double null mouse and investigated the development of lesions in the aortic sinus. Our preliminary data show an unexpected trend where the lesions in apoE/treml1 double null mice have exacerbated compared to apoE or treml1
-/-
mice suggesting that TLT-1 may actually have a anti-inflammatory effect during the progression of atherosclerosis. The status of the current research will be presented here.
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Affiliation(s)
- Marieli Gonzalez
- Dept of Anatomy, Cell and Molecular Biology, Universidad Central del Caribe, Bayamon, Puerto Rico
| | - Fiorella Reyes
- Dept of Anatomy, Cell and Molecular Biology, Universidad Central del Caribe, Bayamon, Puerto Rico
| | - Deborah Marrero
- Dept of Anatomy, Cell and Molecular Biology, Universidad Central del Caribe, Bayamon, Puerto Rico
| | - A Valance Washington
- Dept of Anatomy, Cell and Molecular Biology, Universidad Central del Caribe, Bayamon, Puerto Rico
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Esponda O, Morales J, Aguilar A, Gomez M, Washington AV. Clinical studies support a role for trem-like transcript-1 during the progression of sepsis. Bol Asoc Med P R 2010; 102:59-61. [PMID: 23875522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Sepsis is a multi-factorial disease that kills an estimated 1,400 people a day worldwide. The Triggering Receptor Expressed in Myeloid (TREM) cells Like Transcript (TLT)-1 is a platelet receptor expressed on activated platelets. Translational studies of TLT-1 suggest that TLT-1 affects hemostatic and immunological parameters that lead to the formation of disseminated intravascular coagulation (DIC). Evaluation of mice suffering from endotoxic shock shows a dramatic increase of soluble TLT-1 (sTLT-1) in their blood. Accordingly, when we evaluated the blood of septic patients we find increased levels of sTLT-1 that correlate with the presence of DIC in humans. Based on current data we hypothesize that TLT-1 plays an important role in maintaining vascular integrity during sepsis; perhaps by modulation of both the immune and hemostatic systems, and that TLT-1 makes an attractive target not only for better understanding of sepsis, but also as a point of therapeutic intervention as well.
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Affiliation(s)
- Omar Esponda
- Department of Internal Medicine, Luis Arnau Hospital Regional, Bayamon PR 00959
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21
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Mazzucchelli RI, Warming S, Lawrence SM, Ishii M, Abshari M, Washington AV, Feigenbaum L, Warner AC, Sims DJ, Li WQ, Hixon JA, Gray DHD, Rich BE, Morrow M, Anver MR, Cherry J, Naf D, Sternberg LR, McVicar DW, Farr AG, Germain RN, Rogers K, Jenkins NA, Copeland NG, Durum SK. Visualization and identification of IL-7 producing cells in reporter mice. PLoS One 2009; 4:e7637. [PMID: 19907640 PMCID: PMC2770321 DOI: 10.1371/journal.pone.0007637] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 09/22/2009] [Indexed: 01/06/2023] Open
Abstract
Interleukin-7 (IL-7) is required for lymphocyte development and homeostasis although the actual sites of IL-7 production have never been clearly identified. We produced a bacterial artificial chromosome (BAC) transgenic mouse expressing ECFP in the Il7 locus. The construct lacked a signal peptide and ECFP (enhanced cyan fluorescent protein ) accumulated inside IL-7-producing stromal cells in thoracic thymus, cervical thymus and bone marrow. In thymus, an extensive reticular network of IL-7-containing processes extended from cortical and medullary epithelial cells, closely contacting thymocytes. Central memory CD8 T cells, which require IL-7 and home to bone marrow, physically associated with IL-7-producing cells as we demonstrate by intravital imaging.
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Affiliation(s)
- Renata I. Mazzucchelli
- Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Søren Warming
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, Maryland, United States of America
| | - Scott M. Lawrence
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Masaru Ishii
- Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mehrnoosh Abshari
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - A. Valance Washington
- Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Lionel Feigenbaum
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Andrew C. Warner
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Davis J. Sims
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Wen Qing Li
- Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Julie A. Hixon
- Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Daniel H. D. Gray
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Benjamin E. Rich
- Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Matthew Morrow
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research NCI, Frederick, Maryland, United States of America
| | - Miriam R. Anver
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - James Cherry
- Gene Expression Laboratory, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland, United States of America
| | - Dieter Naf
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Lawrence R. Sternberg
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Daniel W. McVicar
- Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Andrew G. Farr
- Department of Immunology, University of Washington, Seattle, Washington, United States of America
| | - Ronald N. Germain
- Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Keith Rogers
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Nancy A. Jenkins
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, Maryland, United States of America
| | - Neal G. Copeland
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, Maryland, United States of America
| | - Scott K. Durum
- Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
- * E-mail:
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Washington AV, Gibot S, Acevedo I, Gattis J, Quigley L, Feltz R, De La Mota A, Schubert RL, Gomez-Rodriguez J, Cheng J, Dutra A, Pak E, Chertov O, Rivera L, Morales J, Lubkowski J, Hunter R, Schwartzberg PL, McVicar DW. TREM-like transcript-1 protects against inflammation-associated hemorrhage by facilitating platelet aggregation in mice and humans. J Clin Invest 2009; 119:1489-501. [PMID: 19436112 DOI: 10.1172/jci36175] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 03/11/2009] [Indexed: 01/07/2023] Open
Abstract
Triggering receptor expressed on myeloid cells-like (TREM-like) transcript-1 (TLT-1), a type 1 single Ig domain orphan receptor specific to platelet and megakaryocyte alpha-granules, relocates to the platelet surface upon platelet stimulation. We found here that patients diagnosed with sepsis, in contrast to healthy individuals, had substantial levels of soluble TLT-1 (sTLT-1) in their plasma that correlated with the presence of disseminated intravascular coagulation. sTLT-1 bound to fibrinogen and augmented platelet aggregation in vitro. Furthermore, the cytoplasmic domain of TLT-1 could also bind ezrin/radixin/moesin family proteins, suggesting its ability to link fibrinogen to the platelet cytoskeleton. Accordingly, platelets of Treml1-/- mice failed to aggregate efficiently, extending tail-bleeding times. Lipopolysaccharide-treated Treml1-/- mice developed higher plasma levels of TNF and D-dimers than wild-type mice and were more likely to succumb during challenge. Finally, Treml1-/- mice were predisposed to hemorrhage associated with localized inflammatory lesions. Taken together, our findings suggest that TLT-1 plays a protective role during inflammation by dampening the inflammatory response and facilitating platelet aggregation at sites of vascular injury. Therefore, therapeutic modulation of TLT-1-mediated effects may provide clinical benefit to patients with hypercoagulatory conditions, including those associated with inflammation.
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Affiliation(s)
- A Valance Washington
- Laboratory of Anatomy and Cell Biology, Universidad Central del Caribe, Bayamón, Puerto Rico
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Nurden AT, Nurden P, Bermejo E, Combrié R, McVicar DW, Washington AV. Phenotypic heterogeneity in the Gray platelet syndrome extends to the expression of TREM family member, TLT-1. Thromb Haemost 2008; 100:45-51. [PMID: 18612537 DOI: 10.1160/th08-02-0067] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The Gray platelet syndrome (GPS) is a rare inherited disorder linked to undefined molecular abnormalities that prevent the formation and maturation of alpha-granules. Here, we report studies on two patients from unrelated families that confirm phenotypic heterogeneity in the disease. First we used immunoelectron microscopy (I-EM) to confirm that TREM-like transcript-1 (TLT-1) is mostly localized to alpha-granule membranes of normal platelets. Then we performed Western blotting (WB) and flow cytometry with permeabilized platelets to show that TLT-1 is selectively reduced in the platelets of patient 1, previously noted to be deficient in glycoprotein (GP)VI (Nurden et al., Blood 2004; 104: 107-114). Yet both TLT-1 and GPVI were normally expressed in platelets of patient 2. Usual levels of JAM-C and claudin-5, also members of the immunoglobulin receptor family, were detected in platelets of both patients. In contrast, P-selectin was markedly decreased for patient 1 but not patient 2. Two metalloproteases, MMP-2 and MMP-9 were normally present. As predicted, platelets of patient 1 showed little labelling for TLT-1 in I-EM, whereas residual Fg was seen in small vesicular structures and P-selectin lining vacuoles or channels of what may be elements of the surface-connected canalicular system. Our results identify TLT-1 as a glycoprotein potentially targeted in platelets of GPS patients, while decreases in at least three membrane glycoproteins suggest that an unidentified proteolytic activity may contribute to the phenotype in some patients with this rare disease.
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Affiliation(s)
- Alan T Nurden
- Centre de Référence des Pathologies Plaquettaires, Plateforme Technologique et d'Innovation Biomédicale, Hôpital Xavier Arnozan, 33600 Pessac, France.
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24
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Washington AV, McVicar DW. Receptors involved in the regulation of murine NK cells. Curr Protoc Immunol 2008; Appendix 1:Appendix 1R. [PMID: 18432917 DOI: 10.1002/0471142735.ima01rs59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This appendix presents a table of receptors found on murine NK cells. Information is given regarding the specific type of cell(s) in which the particular receptor is found, the chromosomal location, and other names and characteristics including cytoplasmic tyrosine motifs. Only documented receptors and receptor groups are presented, focusing on surface markers found on murine NK cells that regulate the balance between status quo and activation. This appendix also highlights a definite need in the field: the identification of the ligands to these receptors. Less than half of the receptors presented in this table have identified ligands. While the receptors represent advances in understanding the natural killer cell, each unidentified ligand indicates that there is still a long road ahead.
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Affiliation(s)
- A Valance Washington
- Laboratory of Experimental Immunology, National Cancer Institute-Fredrick, Frederick, Maryland, USA
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25
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Durum SK, Warming S, Lawrence SM, Ishii M, Abshari M, Feigenbaum L, Washington AV, Warner AC, Sims DJ, Qing Li W, Hixon JA, Gray DH, Rich BE, Morrow M, Anver MR, Cherry J, Naf D, Sternberg LR, McVicar DW, Farr AG, Germain RN, Rogers K, Copeland NG, Mazzucchelli R. 33 Visualization and Identification of IL-7 Producing Cells. Cytokine 2007. [DOI: 10.1016/j.cyto.2007.07.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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26
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Gattis JL, Washington AV, Chisholm MM, Quigley L, Szyk A, McVicar DW, Lubkowski J. The Structure of the Extracellular Domain of Triggering Receptor Expressed on Myeloid Cells Like Transcript-1 and Evidence for a Naturally Occurring Soluble Fragment. J Biol Chem 2006; 281:13396-13403. [PMID: 16505478 DOI: 10.1074/jbc.m600489200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Triggering receptor expressed on myeloid cells like transcript-1 (TLT-1) is an abundant platelet-specific, type I transmembrane receptor. The extracellular fragment of TLT-1 consists of a single, immunoglobulin-like domain connected to the platelet cell membrane by a linker region called the stalk. Here we present evidence that a soluble fragment of the TLT-1 extracellular domain is found in serum of humans and mice and that an isoform of similar mass is released from platelets following activation with thrombin. We also report the crystal structure of the immunoglobulin domain of TLT-1 determined at the resolution of 1.19 A. The structure of TLT-1 is similar to other immunoglobulin-like variable domains, particularly those of triggering receptor expressed on myeloid cells-1 (TREM-1), the natural killer cell-activating receptor NKp44, and the polymeric immunoglobulin receptor. Particularly interesting is a 17-amino acid segment of TLT-1, homologous to a fragment of murine TREM-1, which, in turn, showed activity in blocking the TREM-1-mediated inflammatory responses in mice. Structural similarity to TREM-1 and polymeric immunoglobulin receptor, and evidence for a naturally occurring soluble fragment of the TLT-1 extracellular domain, suggest that this immunoglobulin-like domain autonomously plays an as yet unidentified, functional role.
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Affiliation(s)
- James L Gattis
- Macromolecular Crystallography Laboratory, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - A Valance Washington
- Laboratory of Experimental Immunology, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Maia M Chisholm
- Laboratory of Experimental Immunology, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Laura Quigley
- Laboratory of Experimental Immunology, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Agnieszka Szyk
- Macromolecular Crystallography Laboratory, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Daniel W McVicar
- Laboratory of Experimental Immunology, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Jacek Lubkowski
- Macromolecular Crystallography Laboratory, NCI, National Institutes of Health, Frederick, Maryland 21702.
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Washington AV, Schubert RL, Quigley L, Disipio T, Feltz R, Cho EH, McVicar DW. A TREM family member, TLT-1, is found exclusively in the α-granules of megakaryocytes and platelets. Blood 2004; 104:1042-7. [PMID: 15100151 DOI: 10.1182/blood-2004-01-0315] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
AbstractThe triggering receptors expressed on myeloid cells (TREMs) have drawn considerable attention due to their ability to activate multiple cell types within the innate immune system, including neutrophils, monocyte/macrophages, and dendritic cells, via their association with DAP12. TLT-1 (TREM-like transcript-1) lies within the TREM gene cluster and contains the characteristic single V-set immunoglobulin (Ig) domain of the family, but its longer cytoplasmic tail is composed of both a proline-rich region and an immune receptor tyrosine-based inhibitory motif, the latter known to be used for interactions with protein tyrosine phosphatases. Here we report that TLT-1 is expressed exclusively in platelets and megakaryocytes (MKs) and that TLT-1 expression is up-regulated dramatically upon platelet activation. Consistent with this observation, confocal microscopy demonstrates that TLT-1 is prepackaged, along with CD62P, into both MK and platelet α-granules. Differences in thrombin-induced redistribution of CD62P and TLT-1 indicate that TLT-1 is not simply cargo of α-granules but may instead regulate granule construction or dispersal. Together these data show that that TLT-1 does not function to inhibit members of the TREM family but instead may play a role in maintaining vascular hemostasis and regulating coagulation and inflammation at sites of injury.
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Washington AV, Quigley L, McVicar DW. Initial characterization of TREM-like transcript (TLT)-1: a putative inhibitory receptor within the TREM cluster. Blood 2002; 100:3822-4. [PMID: 12393607 DOI: 10.1182/blood-2002-02-0523] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The TREMs (triggering receptors expressed on myeloid cells) represent a family of 5 receptors clustered on murine chromosome 17. TREMs 1 and 2 affect various aspects of myeloid cell activation and development, including responsiveness to lipopolysaccharide and regulation of dendritic cell maturation, yet no inhibitory receptor has been demonstrated within this cluster. Here we characterize TLT-1 (TREM-like transcript-1), a putative inhibitory receptor within the TREM cluster that contains an extracellular V-set Ig domain, a proline-rich region, and an immune receptor tyrosine-based inhibitory motif (ITIM) in its cytoplasmic tail. To our knowledge, TLT-1 is the first ITIM-containing receptor carrying a potential Src homology 3 domain ligand. TLT-1 transcripts are abundant in bone marrow cells, but not in lymphocytes, and phosphorylated TLT-1 associates with SHP-1, suggesting that it is indeed an inhibitory receptor. Based on these characteristics, it is likely that TLT-1 regulates the signaling of the TREM family receptors.
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Affiliation(s)
- A Valance Washington
- Laboratory of Experimental Immunology, National Cancer Institute-Frederick, MD 21702, USA
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