1
|
Faulkner M. Risk of progressive multifocal leukoencephalopathy in patients with multiple sclerosis. Expert Opin Drug Saf 2015; 14:1737-48. [DOI: 10.1517/14740338.2015.1093620] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
2
|
Brennan M, Cox D. The therapeutic potential of I-domain integrins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 819:157-78. [PMID: 25023174 DOI: 10.1007/978-94-017-9153-3_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Due to their role in processes central to cancer and autoimmune disease I-domain integrins are an attractive drug target. Both antibodies and small molecule antagonists have been discovered and tested in the clinic. Much of the effort has focused on αLβ2 antagonists. Maybe the most successful was the monoclonal antibody efalizumab, which was approved for the treatment of psoriasis but subsequently withdrawn from the market due to the occurrence of a serious adverse effect (progressive multifocal leukoencephalopathy). Other monoclonal antibodies were tested for the treatment of reperfusion injury, post-myocardial infarction, but failed to progress due to lack of efficacy. New potent small molecule inhibitors of αv integrins are promising reagents for treating fibrotic disease. Small molecule inhibitors targeting collagen-binding integrins have been discovered and future work will focus on identifying molecules selectively targeting each of the collagen receptors and identifying appropriate target diseases for future clinical studies.
Collapse
Affiliation(s)
- Marian Brennan
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland
| | | |
Collapse
|
3
|
|
4
|
Awad AM, Stüve O. Immunopathogenesis of multiple sclerosis: new insights and therapeutic implications. Continuum (Minneap Minn) 2012; 16:166-80. [PMID: 22810604 DOI: 10.1212/01.con.0000389940.92283.aa] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Multiple sclerosis (MS) is an inflammatory, demyelinating, and neurodegenerative disorder of the CNS. The etiology of MS remains unknown. However, it is well established that immune dysregulation plays a critical role in the neuropathogenesis of this disorder. In this review, we discuss the current hypotheses concerning the complex cellular and molecular interactions involved in the immunopathogenesis of MS. Although CD4 T lymphocytes have long been considered the critical cellular factor in the immunopathology of MS, the role of other cell types has also recently been investigated. It appears that the spatial distribution of CD4 and CD8 cells in MS lesions is distinct. Yet another T-lymphocyte subset, γ/δ T cells, can be detected in very early MS lesions. The prevalent dogma suggests that CD4 helper T (TH) type 1 cells release cytokines and inflammatory mediators that cause tissue damage, while CD4 TH2 cells might be involved in modulation of these effects. However, a mounting body of evidence suggests that additional T-cell subsets, including TH17 cells, CD8 effector T cells, and CD4 CD25 regulatory T cells, also affect disease activity. In addition, clinical and paraclinical data are accumulating on the prominent role of B lymphocytes and other antigen-presenting cells in MS neuropathogenesis. Given these observations, new therapeutic interventions for MS will need to focus on resetting multiple components of the immune system.
Collapse
|
5
|
Abstract
Monoclonal antibodies (MAbs) may have great potential as therapies for autoimmune diseases. Their development as treatments for multiple sclerosis (MS) is promising. Partially effective immunomodulatory therapies have been helpful for many MS patients; however, for patients failing these immunomodulatory treatments, MAbs are an important new treatment option. Currently, MAbs are approved by the US Food and Drug Administration for treatment of many conditions, including autoimmune diseases. This article reviews four MAbs that have been investigated as potential treatments for MS. Of these MAbs, natalizumab is approved for treatment of MS. The other three MAbs (alemtuzumab, rituximab, and daclizumab) are all promising therapies in development for treatment of MS. Adverse effects are relatively mild for these MAbs; however, care in administration and management of these agents is emphasized. Overall, these MAb therapies have great promise in the treatment of MS.
Collapse
|
6
|
Abstract
PURPOSE OF REVIEW To review biological therapies as they pertain to the treatment of inflammatory eye diseases, especially uveitis. RECENT FINDINGS Biological therapies including antibodies, soluble receptors, and cytokines are being tested increasingly for a variety of ocular inflammations. As a class, tumor necrosis factor inhibitors have arguably been the most widely employed and have emerged as a successful approach to treat Behçet's disease. Alpha interferon has demonstrated efficacy in the treatment of Behçet's disease and other forms of posterior uveitis. Additional cytokines, cell surface markers, adhesion molecules, and accessory molecules are targets of biological therapy, but the relevance of these targets in eye inflammation is sometimes just theoretical. And any disruption of the immune response entails potential risk. SUMMARY Biological therapies offer tremendous potential in the treatment of ocular inflammation, but their study to date has been limited and both the efficacy and the risk are incompletely known for most of the available interventions.
Collapse
|
7
|
Cox D, Brennan M, Moran N. Integrins as therapeutic targets: lessons and opportunities. Nat Rev Drug Discov 2010; 9:804-20. [PMID: 20885411 DOI: 10.1038/nrd3266] [Citation(s) in RCA: 358] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The integrins are a large family of cell adhesion molecules that are essential for the regulation of cell growth and function. The identification of key roles for integrins in a diverse range of diseases, including cancer, infection, thrombosis and autoimmune disorders, has revealed their substantial potential as therapeutic targets. However, so far, pharmacological inhibitors for only three integrins have received marketing approval. This article discusses the structure and function of integrins, their roles in disease and the chequered history of the approved integrin antagonists. Recent advances in the understanding of integrin function, ligand interaction and signalling pathways suggest novel strategies for inhibiting integrin function that could help harness their full potential as therapeutic targets.
Collapse
Affiliation(s)
- Dermot Cox
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St Stephens Green, Dublin 2, Ireland.
| | | | | |
Collapse
|
8
|
Warnke C, Menge T, Hartung HP, Racke MK, Cravens PD, Bennett JL, Frohman EM, Greenberg BM, Zamvil SS, Gold R, Hemmer B, Kieseier BC, Stüve O. Natalizumab and progressive multifocal leukoencephalopathy: what are the causal factors and can it be avoided? ACTA ACUST UNITED AC 2010; 67:923-30. [PMID: 20697042 DOI: 10.1001/archneurol.2010.161] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Natalizumab (Tysabri) was the first monoclonal antibody approved for the treatment of relapsing forms of multiple sclerosis (MS). After its initial approval, 3 patients undergoing natalizumab therapy in combination with other immunoregulatory and immunosuppressive agents were diagnosed with progressive multifocal leukoencephalopathy (PML). The agent was later reapproved and its use restricted to monotherapy in patients with relapsing forms of MS. Since reapproval in 2006, additional cases of PML were reported in patients with MS receiving natalizumab monotherapy. Thus, there is currently no convincing evidence that natalizumab-associated PML is restricted to combination therapy with other disease-modifying or immunosuppressive agents. In addition, recent data indicate that risk of PML might increase beyond 24 months of treatment.
Collapse
Affiliation(s)
- Clemens Warnke
- Neurology Section, VA North Texas Health Care System, Medical Service, 4500 S Lancaster Rd, Dallas, TX 75216, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Meteesatien P, Plevy SE, Fender JD, Fedoriw Y. Circulating Blasts in a Crohn’s Patient Treated With Natalizumab. Lab Med 2010. [DOI: 10.1309/lm7tq5ti9iiniqwy] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|
10
|
Update on inflammation, neurodegeneration, and immunoregulation in multiple sclerosis: therapeutic implications. Clin Neuropharmacol 2009; 32:121-32. [PMID: 19483479 DOI: 10.1097/wnf.0b013e3181880359] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Multiple sclerosis (MS) is an inflammatory, demyelinating, and neurodegenerative disease of the central nervous system of uncertain etiology. There is consensus that a dysregulated immune system plays a critical role in the pathogenesis of MS; therefore, we aim to summarize current hypotheses concerning the complex cellular and molecular interactions involved in the immunopathology of MS. Although CD4+ T lymphocytes have long been implicated in the immunopathology of MS, the role of other T-cell subtypes has been recognized. CD4+ and CD8+ cells have been isolated from different locations within MS lesions and gamma/delta T cells have been isolated from early MS lesions. The prevalent dogma has been that CD4+ TH1 cells release cytokines and mediators of inflammation that may cause tissue damage, although CD4+ TH2 cells may be involved in modulation of these effects. Recent evidence, however, suggests that additional T-cell subsets play a prominent role in MS immunopathology: TH17 cells, CD8+ effector T cells, and CD4+CD25+ regulatory T cells. In addition, laboratory and clinical data are accumulating on the prominent role of B lymphocytes and antigen-presenting cells in MS pathogenesis. On the basis of these observations, new therapeutic approaches for MS will need to focus on resetting multiple components of the immune system.
Collapse
|
11
|
Rose JW, Foley J, Carlson N. Monoclonal antibody treatments for multiple sclerosis. Curr Neurol Neurosci Rep 2008; 8:419-26. [PMID: 18713579 DOI: 10.1007/s11910-008-0065-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Monoclonal antibodies (MAbs) may have great potential as therapies for autoimmune diseases. Their development as treatments for multiple sclerosis (MS) is promising. Partially effective immunomodulatory therapies have been helpful for many MS patients; however, for patients failing these immunomodulatory treatments, MAbs are an important new treatment option. Currently, MAbs are approved by the US Food and Drug Administration for treatment of many conditions, including autoimmune diseases. Four MAbs that have been investigated as potential treatments for MS are reviewed in this article. Of these MAbs, natalizumab is approved for treatment of MS. The other three MAbs (alemtuzumab, rituximab, and daclizumab) are all promising therapies in development for treatment of MS. Adverse effects are relatively mild for these MAbs; however, care in administration and management of these agents is emphasized. Overall, these MAb therapies have great promise in the treatment of MS.
Collapse
Affiliation(s)
- John W Rose
- Neurovirology Research Laboratory, VA Salt Lake City Health Care System; Department of Neurology, University of Utah Neurovirology Research Laboratory, Salt Lake City, UT 84148, USA.
| | | | | |
Collapse
|
12
|
Yao K, Gagnon S, Akhyani N, Williams E, Fotheringham J, Frohman E, Stuve O, Monson N, Racke MK, Jacobson S. Reactivation of human herpesvirus-6 in natalizumab treated multiple sclerosis patients. PLoS One 2008; 3:e2028. [PMID: 18446218 PMCID: PMC2323568 DOI: 10.1371/journal.pone.0002028] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 03/03/2008] [Indexed: 11/19/2022] Open
Abstract
The alpha(4) integrin antagonist natalizumab was shown to be effective in patients with immune-mediated disorders but was unexpectedly associated with JC polyomavirus associated progressive multifocal leukoencephalopathy (PML) in two multiple sclerosis (MS) and one Crohn's disease patients. Impaired immune surveillance due to natalizumab treatment may have contributed to the JCV reactivation. As HHV-6 has been suggested to play a role in MS, we asked whether this virus could also have been reactivated during natalizumab therapy. Matched sera and CSF from a limited set of MS patients treated with and without natalizumab were examined for evidence of HHV-6. In addition, we also superinfected a persistent JC virus infected glial cell with HHV-6A to determine if JC virus can be increased. Elevated serum HHV6 IgG and HHV-6A DNA was detected in the CSF of a subset of patients but not controls. We confirmed that superinfection with HHV-6 of a JC virus infected glial cells increased expression of JCV. These results support the hypothesis that treatment with natalizumab may be associated with reduced immune surveillance resulting in reactivation of viruses associated with MS pathogenesis.
Collapse
MESH Headings
- Adult
- Antibodies, Monoclonal/pharmacology
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Humanized
- Antibodies, Viral/blood
- Antibodies, Viral/cerebrospinal fluid
- Cell Line
- DNA, Viral/analysis
- DNA, Viral/genetics
- Female
- Herpesvirus 6, Human/drug effects
- Herpesvirus 6, Human/physiology
- Humans
- Immunoglobulin G/blood
- Immunoglobulin G/cerebrospinal fluid
- JC Virus/drug effects
- JC Virus/physiology
- Male
- Middle Aged
- Multiple Sclerosis/drug therapy
- Multiple Sclerosis/virology
- Natalizumab
- Roseolovirus Infections/virology
- Up-Regulation/drug effects
- Virus Activation/drug effects
- Virus Replication/drug effects
Collapse
Affiliation(s)
- Karen Yao
- Viral Immunology Section, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Susan Gagnon
- Viral Immunology Section, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nahid Akhyani
- Viral Immunology Section, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Elizabeth Williams
- Viral Immunology Section, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Julie Fotheringham
- Viral Immunology Section, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Elliot Frohman
- Department of Neurology and the Center for Immunology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Olaf Stuve
- Department of Neurology and the Center for Immunology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Nancy Monson
- Department of Neurology and the Center for Immunology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Michael K. Racke
- Department of Neurology and the Center for Immunology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Steven Jacobson
- Viral Immunology Section, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| |
Collapse
|
13
|
Lindberg RL, Achtnichts L, Hoffmann F, Kuhle J, Kappos L. Natalizumab alters transcriptional expression profiles of blood cell subpopulations of multiple sclerosis patients. J Neuroimmunol 2008; 194:153-64. [DOI: 10.1016/j.jneuroim.2007.11.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Revised: 11/01/2007] [Accepted: 11/12/2007] [Indexed: 11/16/2022]
|
14
|
|
15
|
Stüve O, Bennett JL. Pharmacological properties, toxicology and scientific rationale for the use of natalizumab (Tysabri) in inflammatory diseases. CNS DRUG REVIEWS 2007; 13:79-95. [PMID: 17461891 PMCID: PMC6494150 DOI: 10.1111/j.1527-3458.2007.00003.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Natalizumab (Tysabri) was the first adhesion molecule antagonist to make it into clinical trial for patients with multiple sclerosis (MS) and other inflammatory disorders. Natalizumab is a humanized recombinant monoclonal antibody (MAb) that binds to the alpha (alpha)(4) chain of the alpha(4) beta (beta)(1) (very late activating antigen 4; VLA-4) and alpha(4)beta(7) integrins. The scientific rationale for natalizumab therapy is the reduction of leukocyte extravasation into peripheral tissues. Natalizumab, like other VLA-4 antagonists, may also interfere with the activation of T lymphocytes in secondary lymphoid organs and their reactivation in the central nervous system (CNS). Shortly after its approval for the treatment of relapsing-remitting MS (RR-MS), three patients who were treated with natalizumab in the setting of clinical trials developed progressive multifocal leukoencephalopathy (PML), an opportunistic infection of the brain with the polyoma virus JC. It remains to be elucidated why the use of this VLA-4 antagonist is associated with an increased incidence of PML. Natalizumab was recently reapproved for the treatment of relapsing forms of MS. In this review, we outline the scientific rationale for using natalizumab in MS and other inflammatory disorders. In addition, an overview of pharmacological properties, clinical efficacy, safety, and toxicology of natalizumab is provided.
Collapse
Affiliation(s)
- Olaf Stüve
- Neurology Section, VA North Texas Health Care System, Medical Service, Dallas, Texas, USA
| | | |
Collapse
|
16
|
Abstract
✓Discovery that the Schwann cell is the primary cell type responsible for both the neurofibroma as well as the schwannoma has proven to represent a crucial milestone in understanding the pathogenesis of peripheral nerve tumor development. This information and related findings have served as a nidus for research aimed at more fully characterizing this family of conditions. Recent discoveries in the laboratory have clarified an understanding of the molecular mechanisms underlying the pathogenesis of benign peripheral nerve tumors. Similarly, the mechanisms whereby idiopathic and syndromic (NF1- andNF2-associated) nerve sheath tumors progress to malignancy are being elucidated. This detailed understanding of the molecular pathogenesis of peripheral nerve tumors provides the information necessary to create a new generation of therapies tailored specifically to the prevention, cessation, or reversal of pathological conditions at the fundamental level of dysfunction. The authors review the data that have helped to elucidate the molecular pathogenesis of this category of conditions, explore the current progress toward exploitation of these findings, and discuss potential therapeutic avenues for future research.
Collapse
Affiliation(s)
- Jonathan Riley
- Department of Neurosciences and the Center for Neurological Restoration, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
| | | | | |
Collapse
|
17
|
Deem TL, Abdala-Valencia H, Cook-Mills JM. VCAM-1 activation of endothelial cell protein tyrosine phosphatase 1B. THE JOURNAL OF IMMUNOLOGY 2007; 178:3865-73. [PMID: 17339486 PMCID: PMC2710028 DOI: 10.4049/jimmunol.178.6.3865] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Lymphocytes migrate from the blood into tissue by binding to and migrating across endothelial cells. One of the endothelial cell adhesion molecules that mediate lymphocyte binding is VCAM-1. We have reported that binding to VCAM-1 activates endothelial cell NADPH oxidase for the generation of reactive oxygen species (ROS). The ROS oxidize and stimulate an increase in protein kinase C (PKC)alpha activity. Furthermore, these signals are required for VCAM-1-dependent lymphocyte migration. In this report, we identify a role for protein tyrosine phosphatase 1B (PTP1B) in the VCAM-1 signaling pathway. In primary cultures of endothelial cells and endothelial cell lines, Ab cross-linking of VCAM-1 stimulated an increase in serine phosphorylation of PTP1B, the active form of PTP1B. Ab cross-linking of VCAM-1 also increased activity of PTP1B. This activation of PTP1B was downstream of NADPH oxidase and PKCalpha in the VCAM-1 signaling pathway as determined with pharmacological inhibitors and antisense approaches. In addition, during VCAM-1 signaling, ROS did not oxidize endothelial cell PTP1B. Instead PTP1B was activated by serine phosphorylation. Importantly, inhibition of PTP1B activity blocked VCAM-1-dependent lymphocyte migration across endothelial cells. In summary, VCAM-1 activates endothelial cell NADPH oxidase to generate ROS, resulting in oxidative activation of PKCalpha and then serine phosphorylation of PTP1B. This PTP1B activity is necessary for VCAM-1-dependent transendothelial lymphocyte migration. These data show, for the first time, a function for PTP1B in VCAM-1-dependent lymphocyte migration.
Collapse
Affiliation(s)
- Tracy L. Deem
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45267
- Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908
| | - Hiam Abdala-Valencia
- Allergy-Immunology Division, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45267
| | - Joan M. Cook-Mills
- Allergy-Immunology Division, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45267
- Address correspondence and reprint requests to Dr. Joan M. Cook-Mills, Allergy-Immunology Division, Northwestern University, Feinberg School of Medicine, McGaw-304, 240 East Huron, Chicago, IL 60611. E-mail address:
| |
Collapse
|
18
|
Govindappa V, Hicks S, Wichter M, Jolly M. Progressive multifocal leukoencephalopathy in systemic lupus erythematosus. ACTA ACUST UNITED AC 2007; 57:352-4. [PMID: 17330286 DOI: 10.1002/art.22545] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
19
|
Abdala-Valencia H, Cook-Mills JM. VCAM-1 signals activate endothelial cell protein kinase Calpha via oxidation. THE JOURNAL OF IMMUNOLOGY 2006; 177:6379-87. [PMID: 17056569 PMCID: PMC2711556 DOI: 10.4049/jimmunol.177.9.6379] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Lymphocyte binding to VCAM-1 activates endothelial cell NADPH oxidase, resulting in the generation of 1 muM H(2)O(2). This is required for VCAM-1-dependent lymphocyte migration. In this study, we identified a role for protein kinase Calpha (PKCalpha) in VCAM-1 signal transduction in human and mouse endothelial cells. VCAM-1-dependent spleen cell migration under 2 dynes/cm(2) laminar flow was blocked by pretreatment of endothelial cells with dominant-negative PKCalpha or the PKCalpha inhibitors, Rö-32-0432 or Gö-6976. Phosphorylation of PKCalpha(Thr638), an autophosphorylation site indicating enzyme activity, was increased by Ab cross-linking of VCAM-1 on endothelial cells or by the exogenous addition of 1 muM H(2)O(2). The anti-VCAM-1-stimulated phosphorylation of PKCalpha(Thr638) was blocked by scavenging of H(2)O(2) and by inhibition of NADPH oxidase. Furthermore, anti-VCAM-1 signaling induced the oxidation of endothelial cell PKCalpha. Oxidized PKCalpha is a transiently active form of PKCalpha that is diacylglycerol independent. This oxidation was blocked by inhibition of NADPH oxidase. In summary, VCAM-1 activation of endothelial cell NADPH oxidase induces transient PKCalpha activation that is necessary for VCAM-1-dependent transendothelial cell migration.
Collapse
Affiliation(s)
| | - Joan M. Cook-Mills
- Address correspondence and reprint requests to Dr. Joan M. Cook-Mills, Allergy-Immunology Division, Feinberg School of Medicine, Northwestern University, McGaw-304, 240 East Huron, Chicago, IL 60611. E-mail address:
| |
Collapse
|