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Panigrahi S, Ghosh SK, Ferrari B, Wyrick JM, Podrez EA, Weinberg A, Sieg SF. Human β-Defensin-3 is Associated With Platelet-Derived Extracellular Vesicles and is a Potential Contributor to Endothelial Dysfunction. Front Mol Biosci 2022; 9:824954. [PMID: 35355507 PMCID: PMC8959671 DOI: 10.3389/fmolb.2022.824954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 11/29/2021] [Accepted: 02/16/2022] [Indexed: 11/13/2022] Open
Abstract
While platelets are the essential mediators of hemostasis, they are being increasingly recognized for their potential of contributing to host defenses. Here, using immunofluorescent microscopy, western blot, and ELISA, we found that human β-defensin 3 (hBD-3), an important antimicrobial peptide produced by epithelial cells, can be detected in human platelets and megakaryocytes. Flow cytometry and immuno-electron microscopy revealed hBD-3 on the surface of thrombin activated platelets. Moreover, hBD-3 was also found in platelet derived extracellular vesicles (p-EVs), isolated from platelet poor plasma and from platelet supernatants following thrombin stimulation. Incubation of platelets with hBD-3 peptide resulted in modest platelet activation and pre-incubation of platelets with synthetic hBD-3 prior to exposure to thrombin appeared to increase hBD-3 content in platelet lysates as well as in p-EVs, suggesting that hBD-3 can be initially taken up by platelets, perhaps via their open canalicular system. Interestingly, in vitro exposure of primary human endothelial cells to either hBD-3 peptide or purified p-EVs, caused significant endothelial dysfunction as documented by diminished levels of phosphorylated endothelial nitric oxide synthase (eNOS), Krüppel like factor-2 (KLF-2), and elevated relative expression of von Willebrand Factor (vWF). Pre-incubation of platelets with hBD-3 appeared to augment endothelial dysfunction caused by p-EVs. Overall, the current study provides evidence that hBD-3 enriched EVs can be released by activated platelets and may play a role in positive feedback of platelet activation as well as in endothelial dysfunction. Theoretically, these effects could contribute to both cellular recruitment to the endothelium creating a pro-thrombotic vascular microenvironment which serve as a bridge between innate immunity and hemostasis.
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Affiliation(s)
- Soumya Panigrahi
- Case Western Reserve School of Medicine, Division of Infectious Diseases and HIV Medicine, Cleveland, OH, United States
- *Correspondence: Soumya Panigrahi, ; Scott F. Sieg,
| | - Santosh K. Ghosh
- Department of Biological Sciences, Case Western Reserve University, Cleveland, OH, United States
| | - Brian Ferrari
- Case Western Reserve School of Medicine, Division of Infectious Diseases and HIV Medicine, Cleveland, OH, United States
| | - Jonathan M. Wyrick
- Case Western Reserve School of Medicine, Division of Infectious Diseases and HIV Medicine, Cleveland, OH, United States
- Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Eugene A Podrez
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH, United States
| | - Aaron Weinberg
- Department of Biological Sciences, Case Western Reserve University, Cleveland, OH, United States
| | - Scott F. Sieg
- Case Western Reserve School of Medicine, Division of Infectious Diseases and HIV Medicine, Cleveland, OH, United States
- *Correspondence: Soumya Panigrahi, ; Scott F. Sieg,
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Panigrahi S, Chen B, Fang M, Potashnikova D, Komissarov AA, Lebedeva A, Michaelson GM, Wyrick JM, Morris SR, Sieg SF, Paiardini M, Villinger FJ, Harth K, Kashyap VS, Cameron MJ, Cameron CM, Vasilieva E, Margolis L, Younes SA, Funderburg NT, Zidar DA, Lederman MM, Freeman ML. CX3CL1 and IL-15 Promote CD8 T cell chemoattraction in HIV and in atherosclerosis. PLoS Pathog 2020; 16:e1008885. [PMID: 32976527 PMCID: PMC7540902 DOI: 10.1371/journal.ppat.1008885] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [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: 04/20/2020] [Revised: 10/07/2020] [Accepted: 08/14/2020] [Indexed: 12/14/2022] Open
Abstract
Atherosclerotic cardiovascular disease (ASCVD) remains an important cause of morbidity in the general population and risk for ASCVD is increased approximately 2-fold in persons living with HIV infection (PLWH). This risk is linked to elevated CD8 T cell counts that are abundant in atherosclerotic plaques and have been implicated in disease pathogenesis yet the mechanisms driving T cell recruitment to and activation within plaques are poorly defined. Here we investigated the role of CD8 T cells in atherosclerosis in a non-human primate model of HIV infection and in the HIV-uninfected elderly; we sought to identify factors that promote the activation, function, and recruitment to endothelium of CX3CR1+ CD8 T cells. We measured elevated expression of CX3CL1 and IL-15, and increased CD8 T cell numbers in the aortas of rhesus macaques infected with SIV or SHIV, and demonstrated similar findings in atherosclerotic vessels of HIV-uninfected humans. We found that recombinant TNF enhanced the production and release of CX3CL1 and bioactive IL-15 from aortic endothelial cells, but not from aortic smooth muscle cells. IL-15 in turn promoted CX3CR1 surface expression on and TNF synthesis by CD8 T cells, and IL-15-treated CD8 T cells exhibited enhanced CX3CL1-dependent chemoattraction toward endothelial cells in vitro. Finally, we show that CD8 T cells in human atherosclerotic plaques have an activated, resident phenotype consistent with in vivo IL-15 and CX3CL1 exposure. In this report, we define a novel model of CD8 T cell involvement in atherosclerosis whereby CX3CL1 and IL-15 operate in tandem within the vascular endothelium to promote infiltration by activated CX3CR1+ memory CD8 T cells that drive further endothelial activation via TNF. We propose that these interactions are prevalent in aging and in PLWH, populations where circulating activated CX3CR1+ CD8 T cell numbers are often expanded.
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Affiliation(s)
- Soumya Panigrahi
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine/University Hospitals, Cleveland Medical Center, Cleveland, OH, United States of America
| | - Bonnie Chen
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine/University Hospitals, Cleveland Medical Center, Cleveland, OH, United States of America
| | - Mike Fang
- Department of Population and Quantitative Health Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States of America
| | - Daria Potashnikova
- Laboratory of Atherothrombosis, Moscow State University of Medicine and Dentistry, Moscow, Russia
- Department of Cell Biology and Histology, School of Biology, Moscow State University, Moscow, Russia
| | - Alexey A. Komissarov
- Laboratory of Atherothrombosis, Moscow State University of Medicine and Dentistry, Moscow, Russia
| | - Anna Lebedeva
- Laboratory of Atherothrombosis, Moscow State University of Medicine and Dentistry, Moscow, Russia
| | - Gillian M. Michaelson
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine/University Hospitals, Cleveland Medical Center, Cleveland, OH, United States of America
| | - Jonathan M. Wyrick
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine/University Hospitals, Cleveland Medical Center, Cleveland, OH, United States of America
| | - Stephen R. Morris
- Cleveland Louis Stokes Veterans Affairs Medical Center, Cleveland, OH, United States of America
| | - Scott F. Sieg
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine/University Hospitals, Cleveland Medical Center, Cleveland, OH, United States of America
| | - Mirko Paiardini
- Division of Microbiology and Immunology, Yerkes National Primate Research Center, and Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, United States of America
| | - Francois J. Villinger
- New Iberia Research Center, University of Louisiana at Lafayette, New Iberia, LA, United States of America
| | - Karem Harth
- Harrington Heart & Vascular Institute, University Hospitals, Cleveland Medical Center/Case Western Reserve University, School of Medicine, Cleveland, OH, United States of America
| | - Vikram S. Kashyap
- Harrington Heart & Vascular Institute, University Hospitals, Cleveland Medical Center/Case Western Reserve University, School of Medicine, Cleveland, OH, United States of America
| | - Mark J. Cameron
- Department of Population and Quantitative Health Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States of America
| | - Cheryl M. Cameron
- Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH, United States of America
| | - Elena Vasilieva
- Laboratory of Atherothrombosis, Moscow State University of Medicine and Dentistry, Moscow, Russia
| | - Leonid Margolis
- Section on Intercellular Interactions, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Souheil-Antoine Younes
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine/University Hospitals, Cleveland Medical Center, Cleveland, OH, United States of America
| | - Nicholas T. Funderburg
- School of Health and Rehabilitation Sciences, Ohio State University, Columbus, OH, United States of America
| | - David A. Zidar
- Cleveland Louis Stokes Veterans Affairs Medical Center, Cleveland, OH, United States of America
- Harrington Heart & Vascular Institute, University Hospitals, Cleveland Medical Center/Case Western Reserve University, School of Medicine, Cleveland, OH, United States of America
| | - Michael M. Lederman
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine/University Hospitals, Cleveland Medical Center, Cleveland, OH, United States of America
| | - Michael L. Freeman
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine/University Hospitals, Cleveland Medical Center, Cleveland, OH, United States of America
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Chen B, Morris SR, Panigrahi S, Michaelson GM, Wyrick JM, Komissarov AA, Potashnikova D, Lebedeva A, Younes SA, Harth K, Kashyap VS, Vasilieva E, Margolis L, Zidar DA, Sieg SF, Shive CL, Funderburg NT, Gianella S, Lederman MM, Freeman ML. Cytomegalovirus Coinfection Is Associated with Increased Vascular-Homing CD57 + CD4 T Cells in HIV Infection. J Immunol 2020; 204:2722-2733. [PMID: 32229536 PMCID: PMC7315224 DOI: 10.4049/jimmunol.1900734] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 02/26/2020] [Indexed: 12/17/2022]
Abstract
Cytotoxic CD4 T cells are linked to cardiovascular morbidities and accumulate in both HIV and CMV infections, both of which are associated with increased risk of cardiovascular disease (CVD). In this study, we identify CMV coinfection as a major driver of the cytotoxic phenotype, characterized by elevated CD57 expression and reduced CD28 expression, in circulating CD4 T cells from people living with HIV infection, and investigate potential mechanisms linking this cell population to CVD. We find that human CD57+ CD4 T cells express high levels of the costimulatory receptor CD2 and that CD2/LFA-3 costimulation results in a more robust and polyfunctional effector response to TCR signals, compared with CD28-mediated costimulation. CD57+ CD4 T cells also express the vascular endothelium-homing receptor CX3CR1 and migrate toward CX3CL1-expressing endothelial cells in vitro. IL-15 promotes the cytotoxic phenotype, elevates CX3CR1 expression, and enhances the trafficking of CD57+ CD4 T cells to endothelium and may therefore be important in linking these cells to cardiovascular complications. Finally, we demonstrate the presence of activated CD57+ CD4 T cells and expression of CX3CL1 and LFA-3 in atherosclerotic plaque tissues from HIV-uninfected donors. Our findings are consistent with a model in which cytotoxic CD4 T cells contribute to CVD in HIV/CMV coinfection and in atherosclerosis via CX3CR1-mediated trafficking and CD2/LFA-3-mediated costimulation. This study identifies several targets for therapeutic interventions and may help bridge the gap in understanding how CMV infection and immunity are linked to increased cardiovascular risk in people living with HIV infection.
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Affiliation(s)
- Bonnie Chen
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University/University Hospitals Cleveland Medical Center, Cleveland, OH 44106
| | - Stephen R Morris
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106
| | - Soumya Panigrahi
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University/University Hospitals Cleveland Medical Center, Cleveland, OH 44106
| | - Gillian M Michaelson
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University/University Hospitals Cleveland Medical Center, Cleveland, OH 44106
| | - Jonathan M Wyrick
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University/University Hospitals Cleveland Medical Center, Cleveland, OH 44106
| | - Alexey A Komissarov
- Laboratory of Atherothrombosis, Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
| | - Daria Potashnikova
- Laboratory of Atherothrombosis, Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
- Department of Cell Biology and Histology, School of Biology, Moscow State University, Moscow 119234, Russia
| | - Anna Lebedeva
- Laboratory of Atherothrombosis, Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
| | - Souheil-Antoine Younes
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University/University Hospitals Cleveland Medical Center, Cleveland, OH 44106
| | - Karem Harth
- Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center/Case Western Reserve University, Cleveland, OH 44106
| | - Vikram S Kashyap
- Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center/Case Western Reserve University, Cleveland, OH 44106
| | - Elena Vasilieva
- Laboratory of Atherothrombosis, Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
| | - Leonid Margolis
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - David A Zidar
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106
- Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center/Case Western Reserve University, Cleveland, OH 44106
| | - Scott F Sieg
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University/University Hospitals Cleveland Medical Center, Cleveland, OH 44106
| | - Carey L Shive
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106
| | - Nicholas T Funderburg
- Division of Medical Laboratory Science, School of Health and Rehabilitation Sciences, Ohio State University, Columbus, OH 43210; and
| | - Sara Gianella
- Center for AIDS Research, Division of Infectious Diseases, Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Michael M Lederman
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University/University Hospitals Cleveland Medical Center, Cleveland, OH 44106
| | - Michael L Freeman
- Center for AIDS Research, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University/University Hospitals Cleveland Medical Center, Cleveland, OH 44106;
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Freeman ML, Chen B, Morris SR, Panigrahi S, Michaelson GM, Wyrick JM, Komissarov AA, Potashnikova D, Lebedeva A, Younes SA, Harth K, Kashyap VS, Vasilieva E, Margolis L, Zidar DA, Sieg SF, Shive CL, Funderburg NT, Gianella S, Lederman MM. Cytomegalovirus coinfection is associated with increased vascular-homing CD57+ CD4 T cells in HIV infection. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.225.38] [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: 01/03/2023]
Abstract
Abstract
Cytotoxic CD4 T cells are linked to cardiovascular morbidities and accumulate in both human immunodeficiency virus (HIV) and cytomegalovirus (CMV) infections, both of which are associated with increased risk of cardiovascular disease. Here we identify CMV coinfection as a major driver of the cytotoxic phenotype – characterized by elevated CD57 expression and reduced CD28 expression – in circulating CD4 T cells from people living with HIV infection (PLWH). We find that CD57+ CD4 T cells express high levels of the costimulatory receptor CD2 and that CD2/LFA-3 costimulation results in a more robust and polyfunctional effector response to T cell receptor (TCR) signals, compared to CD28-mediated costimulation. CD57+ CD4 T cells also express the vascular endothelium-homing receptor CX3CR1 and migrate toward CX3CL1-expressing endothelial cells in vitro. IL-15 promotes the cytotoxic phenotype, elevates CX3CR1 expression, and enhances the trafficking of CD57+ CD4 T cells, and may therefore be important in linking these cells to cardiovascular complications. Finally, we demonstrate the presence of CD57+ CD4 T cells and expression of IL-15, CX3CL1, and LFA-3 in atherosclerotic plaque tissues from HIV-uninfected donors. Our findings are consistent with a model in which cytotoxic CD4 T cells contribute to cardiovascular disease in HIV/CMV coinfection and in atherosclerosis via CX3CR1-mediated trafficking and CD2-mediated costimulation, and may help bridge the gap in understanding how CMV infection and immunity are linked to increased cardiovascular risk in PLWH.
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Affiliation(s)
- Michael L Freeman
- 1Division of Infectious Diseases, Case Western Reserve University, Cleveland, OH
| | - Bonnie Chen
- 1Division of Infectious Diseases, Case Western Reserve University, Cleveland, OH
| | - Stephen R Morris
- 2Louis Stokes Cleveland VA Med. Ctr
- 3Univ. of Miami Miller Sch. of Med
| | - Soumya Panigrahi
- 1Division of Infectious Diseases, Case Western Reserve University, Cleveland, OH
| | - Gillian M Michaelson
- 1Division of Infectious Diseases, Case Western Reserve University, Cleveland, OH
| | - Jonathan M Wyrick
- 1Division of Infectious Diseases, Case Western Reserve University, Cleveland, OH
| | | | - Daria Potashnikova
- 4Moscow State Univ. of Med. and Dent., Russia
- 5Moscow State Univ., Russia
| | | | | | - Karem Harth
- 6Harrington Heart & Vascular Institute, University Hospitals Cleveland Medical Center
| | - Vikram S Kashyap
- 6Harrington Heart & Vascular Institute, University Hospitals Cleveland Medical Center
| | | | | | - David A Zidar
- 2Louis Stokes Cleveland VA Med. Ctr
- 6Harrington Heart & Vascular Institute, University Hospitals Cleveland Medical Center
| | - Scott F Sieg
- 1Division of Infectious Diseases, Case Western Reserve University, Cleveland, OH
| | | | | | | | - Michael M Lederman
- 1Division of Infectious Diseases, Case Western Reserve University, Cleveland, OH
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Abstract
BACKGROUND Epidemiologic studies have shown that undocumented immigrants (UIs) display characteristics of having a low socioeconomic status and are primarily of ethnic minorities. These social determinants of health are known to be associated with diminished health care access and poor clinical outcomes. We therefore investigated the impact of documentation status on the clinical outcomes of patients with traumatic injuries. MATERIALS AND METHODS We conducted a retrospective review of the trauma registry at our safety net institution for all adult patients who were admitted from 2010 to 2014. UIs were identified by the absence of a valid social security number within their medical records. Multivariate regression analysis was used to determine the impact of documentation status on in-hospital mortality, length of stay (LOS), and the odds of rehab placement. RESULTS 4924 trauma patients met the study criteria, of which 1050 (21.3%) were UIs. There was no significant difference in mortality rates between the two populations. Multivariate regression analyses revealed a longer average LOS and a decreased likelihood for placement in an in-patient rehabilitation facility following hospitalization for UIs, even after accounting for insurance, age, injury severity, and other possible confounders known to affect these outcomes. CONCLUSIONS There was no association between in-hospital mortality and documentation status; however, UIs had a longer average LOS and were less likely to be placed into rehab following their hospitalization. A longer LOS and a decreased likelihood for rehabilitation placement suggest that disparities in trauma care exist for UIs, putting them at risk for worse clinical and functional outcomes.
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Affiliation(s)
- Jonathan M Wyrick
- Department of Surgery, Elmhurst Hospital Center, Icahn School of Medicine at Mount Sinai, Elmhurst, New York
| | - Brittany A Kalosza
- Department of Surgery, Elmhurst Hospital Center, Icahn School of Medicine at Mount Sinai, Elmhurst, New York
| | - George N Coritsidis
- Department of Surgery, Elmhurst Hospital Center, Icahn School of Medicine at Mount Sinai, Elmhurst, New York.
| | - Raymond Tse
- Department of Surgery, Elmhurst Hospital Center, Icahn School of Medicine at Mount Sinai, Elmhurst, New York
| | - George Agriantonis
- Department of Surgery, Elmhurst Hospital Center, Icahn School of Medicine at Mount Sinai, Elmhurst, New York
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Gillis WQ, Kirmizitas A, Iwasaki Y, Ki DH, Wyrick JM, Thomsen GH. Gtpbp2 is a positive regulator of Wnt signaling and maintains low levels of the Wnt negative regulator Axin. Cell Commun Signal 2016; 14:15. [PMID: 27484226 PMCID: PMC4969687 DOI: 10.1186/s12964-016-0138-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [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] [Received: 03/03/2016] [Accepted: 07/29/2016] [Indexed: 12/29/2022] Open
Abstract
Background Canonical Wnt signals, transduced by stabilized β-catenin, play similar roles across animals in maintaining stem cell pluripotency, regulating cell differentiation, and instructing normal embryonic development. Dysregulated Wnt/β-catenin signaling causes diseases and birth defects, and a variety of regulatory processes control this pathway to ensure its proper function and integration with other signaling systems. We previously identified GTP-binding protein 2 (Gtpbp2) as a novel regulator of BMP signaling, however further exploration revealed that Gtpbp2 can also affect Wnt signaling, which is a novel finding reported here. Results Knockdown of Gtpbp2 in Xenopus embryos causes severe axial defects and reduces expression of Spemann-Mangold organizer genes. Gtpbp2 knockdown blocks responses to ectopic Wnt8 ligand, such as organizer gene induction in ectodermal tissue explants and induction of secondary axes in whole embryos. However, organizer gene induction by ectopic Nodal2 is unaffected by Gtpbp2 knockdown. Epistasis tests, conducted by activating Wnt signal transduction at sequential points in the canonical pathway, demonstrate that Gtpbp2 is required downstream of Dishevelled and Gsk3β but upstream of β-catenin, which is similar to the previously reported effects of Axin1 overexpression in Xenopus embryos. Focusing on Axin in Xenopus embryos, we find that knockdown of Gtpbp2 elevates endogenous or exogenous Axin protein levels. Furthermore, Gtpbp2 fusion proteins co-localize with Dishevelled and co-immunoprecipitate with Axin and Gsk3b. Conclusions We conclude that Gtpbp2 is required for canonical Wnt/β-catenin signaling in Xenopus embryos. Our data suggest a model in which Gtpbp2 suppresses the accumulation of Axin protein, a rate-limiting component of the β-catenin destruction complex, such that Axin protein levels negatively correlate with Gtpbp2 levels. This model is supported by the similarity of our Gtpbp2-Wnt epistasis results and previously reported effects of Axin overexpression, the physical interactions of Gtpbp2 with Axin, and the correlation between elevated Axin protein levels and lost Wnt responsiveness upon Gtpbp2 knockdown. A wide variety of cancer-causing Wnt pathway mutations require low Axin levels, so development of Gtpbp2 inhibitors may provide a new therapeutic strategy to elevate Axin and suppress aberrant β-catenin signaling in cancer and other Wnt-related diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12964-016-0138-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- William Q Gillis
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY, 11794-5215, USA.,Present Address: Department of Biological Sciences, State University of New York, College at Old Westbury, Old Westbury, NY, 11568, USA
| | - Arif Kirmizitas
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY, 11794-5215, USA.,Present Address: The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DS, UK
| | - Yasuno Iwasaki
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY, 11794-5215, USA
| | - Dong-Hyuk Ki
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY, 11794-5215, USA.,Present Address: Department of Pediatric Oncology, Dana-Farber Cancer Institute, Division of Hematology/Oncology, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
| | - Jonathan M Wyrick
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY, 11794-5215, USA
| | - Gerald H Thomsen
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY, 11794-5215, USA.
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Abstract
A survey was conducted of 192 work-hardening and work-adjustment programs to gain an overview of practice patterns. The questionnaire covered program affiliation, services offered, staffing, program scheduling, average length of treatment per client, equipment used, physical settings, program status, number of clients seen each week, and types of functional outcome studies and research. The results demonstrate the tremendous growth of the involvement of occupational therapy in work hardening. This demographic study provides baseline information that can assist in the examination of trends and the development of new programs.
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Affiliation(s)
- J M Wyrick
- Department of Occupational Therapy Education, School of Allied Health, University of Kansas Medical Center, Kansas City 66103
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8
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Abstract
This national survey was designed to study selected characteristics of entry level occupational therapy students and to compare recruitment variables in technical and professional students. The survey encompassed 116 programs with 1,843 students responding. Major findings include the following: the median age of professional students was 1 to 2 years older than that of technical students; the technical students had the larger percentage of older students; professional level students chose occupational therapy at an earlier age than did technical students; the majority of minority students were enrolled in technical programs; and students' initial exposure to occupational therapy differed between the technical and professional students: Technical students reported that their earliest contacts with the profession most often came from family friends, college and junior college contacts, high school counselors, and occupational therapy students, in that order. Professional level students reported that their most common initial contact came from occupational therapy students, family friends, parents, a volunteer or employment experience in the field, or health personnel in the field, in that order. Survey data form the basis for a discussion of potential expansion of recruitment strategies.
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9
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Wyrick JM. Lack of effect on attitude change of two films dealing with cerebral palsy. Am J Occup Ther 1967; 21:76-8. [PMID: 6044867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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