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van Haaren MJH, Steller LB, Vastert SJ, Calis JJA, van Loosdregt J. Get Spliced: Uniting Alternative Splicing and Arthritis. Int J Mol Sci 2024; 25:8123. [PMID: 39125692 PMCID: PMC11311815 DOI: 10.3390/ijms25158123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 07/21/2024] [Accepted: 07/22/2024] [Indexed: 08/12/2024] Open
Abstract
Immune responses demand the rapid and precise regulation of gene protein expression. Splicing is a crucial step in this process; ~95% of protein-coding gene transcripts are spliced during mRNA maturation. Alternative splicing allows for distinct functional regulation, as it can affect transcript degradation and can lead to alternative functional protein isoforms. There is increasing evidence that splicing can directly regulate immune responses. For several genes, immune cells display dramatic changes in isoform-level transcript expression patterns upon activation. Recent advances in long-read RNA sequencing assays have enabled an unbiased and complete description of transcript isoform expression patterns. With an increasing amount of cell types and conditions that have been analyzed with such assays, thousands of novel transcript isoforms have been identified. Alternative splicing has been associated with autoimmune diseases, including arthritis. Here, GWASs revealed that SNPs associated with arthritis are enriched in splice sites. In this review, we will discuss how alternative splicing is involved in immune responses and how the dysregulation of alternative splicing can contribute to arthritis pathogenesis. In addition, we will discuss the therapeutic potential of modulating alternative splicing, which includes examples of spliceform-based biomarkers for disease severity or disease subtype, splicing manipulation using antisense oligonucleotides, and the targeting of specific immune-related spliceforms using antibodies.
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Affiliation(s)
- Maurice J. H. van Haaren
- Center for Translational Immunology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Levina Bertina Steller
- Center for Translational Immunology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Sebastiaan J. Vastert
- Center for Translational Immunology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
- Division of Pediatric Rheumatology and Immunology, Wilhelmina Children’s Hospital, 3584 CX Utrecht, The Netherlands
| | - Jorg J. A. Calis
- Center for Translational Immunology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Jorg van Loosdregt
- Center for Translational Immunology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
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Plasma fibronectin stabilizes Borrelia burgdorferi-endothelial interactions under vascular shear stress by a catch-bond mechanism. Proc Natl Acad Sci U S A 2017; 114:E3490-E3498. [PMID: 28396443 DOI: 10.1073/pnas.1615007114] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial dissemination via the cardiovascular system is the most common cause of infection mortality. A key step in dissemination is bacterial interaction with endothelia lining blood vessels, which is physically challenging because of the shear stress generated by blood flow. Association of host cells such as leukocytes and platelets with endothelia under vascular shear stress requires mechanically specialized interaction mechanisms, including force-strengthened catch bonds. However, the biomechanical mechanisms supporting vascular interactions of most bacterial pathogens are undefined. Fibronectin (Fn), a ubiquitous host molecule targeted by many pathogens, promotes vascular interactions of the Lyme disease spirochete Borrelia burgdorferi Here, we investigated how B. burgdorferi exploits Fn to interact with endothelia under physiological shear stress, using recently developed live cell imaging and particle-tracking methods for studying bacterial-endothelial interaction biomechanics. We found that B. burgdorferi does not primarily target insoluble matrix Fn deposited on endothelial surfaces but, instead, recruits and induces polymerization of soluble plasma Fn (pFn), an abundant protein in blood plasma that is normally soluble and nonadhesive. Under physiological shear stress, caps of polymerized pFn at bacterial poles formed part of mechanically loaded adhesion complexes, and pFn strengthened and stabilized interactions by a catch-bond mechanism. These results show that B. burgdorferi can transform a ubiquitous but normally nonadhesive blood constituent to increase the efficiency, strength, and stability of bacterial interactions with vascular surfaces. Similar mechanisms may promote dissemination of other Fn-binding pathogens.
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Scanzello CR, Markova DZ, Chee A, Xiu Y, Adams SL, Anderson G, Zgonis M, Qin L, An HS, Zhang Y. Fibronectin splice variation in human knee cartilage, meniscus and synovial membrane: observations in osteoarthritic knee. J Orthop Res 2015; 33:556-62. [PMID: 25410897 PMCID: PMC4586164 DOI: 10.1002/jor.22787] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/07/2014] [Indexed: 02/04/2023]
Abstract
Fibronectin (FN) is a widely expressed molecule that can participate in development of osteoarthritis (OA) affecting cartilage, meniscus, and synovial membrane (SM). The alternatively spliced isoforms of FN in joint tissues other than cartilage have not been extensively studied previously. The present study compares FN splice variation in patients with varying degrees of osteoarthritic change. Joint tissues were collected from asymptomatic donors and patients undergoing arthroscopic procedures. Total RNA was amplified by PCR using primers flanking alternatively spliced Extra Domain A (EDA), Extra Domain B (EDB) and Variable (V) regions. EDB(+) , EDB(-) and EDA(-) and V(+) variants were present in all joint tissues, while the EDA(+) variant was rarely detected. Expression levels of EDB(+) and EDV(+) variants were similar in cartilage, synovium, and meniscal tissues. Synovial expression of V(+) FN in arthroscopy patients varied with degree of cartilage degeneration. Two V(-) isoforms, previously identified in cartilage, were also present in SM and meniscus. Fibronectin splicing in meniscus and SM bears striking resemblance to that of cartilage. Expression levels of synovial V(+) FN varied with degree of cartilage degeneration. V(+) FN should be investigated as a potential biomarker of disease stage or progression in larger populations.
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Affiliation(s)
- Carla R. Scanzello
- Philadelphia Veterans Affairs Medical Center, and Department of Medicine, Division of Rheumatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | - Ana Chee
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL
| | - Yan Xiu
- Department of Physical Medicine and Rehabilitation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Sherrill L. Adams
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA
| | - Greg Anderson
- Department of Orthopedic Surgery, Thomas Jefferson University, Philadelphia, PA
| | - Miltiadis Zgonis
- Department of Physical Medicine and Rehabilitation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ling Qin
- Department of Physical Medicine and Rehabilitation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Howard S. An
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL
| | - Yejia Zhang
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL,Philadelphia Veterans Affairs Medical Center, and Department of Physical Medicine and Rehabilitation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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Sandig H, McDonald J, Gilmour J, Arno M, Lee TH, Cousins DJ. Fibronectin is a TH1-specific molecule in human subjects. J Allergy Clin Immunol 2009; 124:528-35, 535.e1-5. [PMID: 19541353 DOI: 10.1016/j.jaci.2009.04.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 04/28/2009] [Accepted: 04/28/2009] [Indexed: 12/26/2022]
Abstract
BACKGROUND T(H)1 cell-mediated immunity is essential for host defense against a variety of intracellular pathogens, such as mycobacteria, salmonella, and Leishmania species. A major T(H)1-mediated effector mechanism involves the IFN-gamma-induced killing of the pathogen by infected macrophages. OBJECTIVES The range of known T(H)1-specific effector molecules is limited, especially in human subjects. We sought to identify novel effector molecules that might be involved in T(H)1-mediated pathogen clearance. METHODS We performed microarray-based analysis of human T(H)1 and T(H)2 cells to identify T(H)1-specific molecules. These analyses identified the extracellular matrix molecule fibronectin as a highly expressed T(H)1-specific molecule. We examined the expression of fibronectin in a variety of human cell types by using real-time RT-PCR, ELISA, and Western blotting. We also studied the role of fibronectin in modulating monocyte phenotype using in vitro culture. RESULTS We show that human T(H)1 cells constitutively express and secrete fibronectin after in vitro differentiation from naive precursors. Furthermore, we demonstrate that ex vivo human T(H)1 cells selectively express fibronectin when compared with T(H)2 cells. The predominant isoform of fibronectin expressed by T(H)1 cells contains additional domains of the protein responsible for alpha4beta1 integrin binding and activation of Toll-like receptor 4. We show that treatment of monocytes with T(H)1 cell-derived fibronectin induces expression of the proinflammatory cytokine IL-6 while inhibiting IL-10 expression. CONCLUSIONS Because fibronectin also plays a major role in the attachment and opsonization of numerous intracellular pathogens, we propose that it might be a critical molecule produced by T(H)1 cells involved in pathogen eradication.
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Affiliation(s)
- Hilary Sandig
- Medical Research Council and Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, Guy's Hospital, London, United Kingdom
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Gibson DS, Rooney ME. The human synovial fluid proteome: A key factor in the pathology of joint disease. Proteomics Clin Appl 2007; 1:889-99. [DOI: 10.1002/prca.200700044] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Indexed: 12/29/2022]
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van Keulen JK, de Kleijn DP, Nijhuis MMO, Busser E, Velema E, Fijnheer R, van der Graaf Y, Moll FL, de Vries JP, Pasterkamp G. Levels of extra domain A containing fibronectin in human atherosclerotic plaques are associated with a stable plaque phenotype. Atherosclerosis 2007; 195:e83-91. [PMID: 17416372 DOI: 10.1016/j.atherosclerosis.2007.03.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 03/02/2007] [Accepted: 03/08/2007] [Indexed: 01/07/2023]
Abstract
BACKGROUND Extra domain A (EDA), splice-variant of fibronectin, is a Toll-like receptor 4 (Tlr4) ligand. Recently, EDA has been demonstrated to enhance atherogenesis in mice but human data on the role of EDA in atherosclerotic disease are lacking. We hypothesized that EDA is associated with unstable plaque phenotypes and that plasma EDA could serve as biomarker for atherosclerosis. METHODS EDA levels were assessed in carotid endarterectomy specimen (206 patients) and related with plaque phenotype. In a second patient cohort, systemic EDA levels in atherosclerotic patients (73 patients) were compared to risk-factor matched controls (68 patients). RESULTS EDA plaque levels were associated with characteristics of stable plaques; more smooth muscle cells (P=0.003), more collagen (P=0.071) and less fat (P=0.023). Concomitantly, asymptomatic patients showed higher EDA values in the plaque compared to symptomatic patients (P=0.004). EDA plasma levels did not differ between atherosclerotic patients versus controls (P=0.134). CONCLUSION EDA plaque levels are higher in asymptomatic patients and are associated with a stable plaque phenotype. EDA is not a plasma marker for atherosclerotic disease. These results suggest that local presence of endogenous Tlr4 ligand EDA is not associated with in an unstable plaque phenotype in humans.
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Affiliation(s)
- J Karlijn van Keulen
- Experimental Cardiology Laboratory, Cardiology, University Medical Center Utrecht, The Netherlands
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Abstract
The focus of this article is to review the recent advances in proteome analysis of human body fluids, including plasma/serum, urine, cerebrospinal fluid, saliva, bronchoalveolar lavage fluid, synovial fluid, nipple aspirate fluid, tear fluid, and amniotic fluid, as well as its applications to human disease biomarker discovery. We aim to summarize the proteomics technologies currently used for global identification and quantification of body fluid proteins, and elaborate the putative biomarkers discovered for a variety of human diseases through human body fluid proteome (HBFP) analysis. Some critical concerns and perspectives in this emerging field are also discussed. With the advances made in proteomics technologies, the impact of HBFP analysis in the search for clinically relevant disease biomarkers would be realized in the future.
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Affiliation(s)
- Shen Hu
- School of Dentistry, Division of Oral Biology and Medicine, Dental Research Institute, University of California, Los Angeles, CA 90095, USA.
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Leonardi R, Michelotti A, Farella M, Caltabiano R, Lanzafame S. Fibronectin Upregulation in Human Temporomandibular Joint Disks With Internal Derangement. J Craniofac Surg 2004; 15:678-83; discussion 684-5. [PMID: 15213552 DOI: 10.1097/00001665-200407000-00028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Fibronectin is a large fibril-forming extracellular glycoprotein that seems to be involved in joint diseases. The objective of this study was to investigate the expression of fibronectin in human temporomandibular joint disks obtained from patients with internal derangement and varying extents of disk tissue degeneration/regeneration with that of temporomandibular joint disks free of significant morphological alterations by means of immunohistochemical methods. Twelve adult human temporomandibular joint disks (10 diseased disks and 2 normal disks) were used in this study. Temporomandibular joint disks were fixed in 10% buffered formalin. Sections were then immunohistochemically processed using a monoclonal antibody specific to human fibronectin and streptavidin-biotin detection methods. Positive reactions to fibronectin were found in normal and diseased disk tissues but to a different extent. Normal disk tissues revealed weak fibronectin expression, which was mainly located along the collagen bundles. Temporomandibular joint disks with internal derangement exhibited a higher immunoreactivity. Distinct reticular fibronectin structures were found inside the diseased disk, particularly nearby the newly formed blood vessels, tears, and clefts. In the covering layer of the disk surface, fibronectin was expressed in a fascicular pattern running parallel to the disk surface. The findings suggest that temporomandibular joint disk tissue can express fibronectin and that the expression is more pronounced in disk specimens of patients with internal derangement of the temporomandibular joint, supporting a role of this glycoprotein in the degeneration/regeneration processes of human temporomandibular joint disk tissue.
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Affiliation(s)
- Rosalia Leonardi
- Department of Medical and Surgical Sciences, II Dental Unit, University of Catania, Catania, Italy.
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Tan MH, Sun Z, Opitz SL, Schmidt TE, Peters JH, George EL. Deletion of the alternatively spliced fibronectin EIIIA domain in mice reduces atherosclerosis. Blood 2004; 104:11-8. [PMID: 14976060 DOI: 10.1182/blood-2003-09-3363] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe alternatively spliced and highly conserved EIIIA domain of fibronectin (FN) is included in most FN of the extracellular matrix in embryos. In adults, both extracellular matrix and plasma FN essentially lack EIIIA. In diverse inflammatory situations however, EIIIA is specifically included by regulated RNA splicing. In atherosclerotic lesions, FN, including the EIIIA domain (EIIIA-FN), is abundant, whereas FN in the flanking vessel wall lacks EIIIA. Lesional EIIIA-FN is localized with endothelial cells and macrophage foam cells. To directly test the function of EIIIA-FN, we generated EIIIA-null (EIIIA–/–) mice that lack the EIIIA exon and crossed them with apolipoprotein E (ApoE)–null (ApoE–/–) mice that develop arterial wall lesions. Compared with ApoE–/– controls, EIIIA–/–ApoE–/– mice had significantly smaller lesions throughout the aortic tree. EIIIA-FN was increased in ApoE–/– plasma, and total plasma cholesterol was reduced in EIIIA–/–ApoE–/– mice, specifically in large lipoprotein particles, suggesting a functional role for plasma EIIIA-FN. To assess a role for macrophage EIIIA-FN in the vessel wall, we conducted in vitro foam cell assays. EIIIA–/–ApoE–/– macrophages accumulated significantly less intracellular lipid than control ApoE–/– cells. These results provide genetic evidence that suggests roles for EIIIA-FN in plasma lipoprotein metabolism and in foam cell formation.
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Affiliation(s)
- Michelle H Tan
- Vascular Research Division, Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA
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Peters JH, Carsons S, Yoshida M, Ko F, McDougall S, Loredo GA, Hahn TJ. Electrophoretic characterization of species of fibronectin bearing sequences from the N-terminal heparin-binding domain in synovial fluid samples from patients with osteoarthritis and rheumatoid arthritis. Arthritis Res Ther 2003; 5:R329-39. [PMID: 14680507 PMCID: PMC333412 DOI: 10.1186/ar1001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2003] [Revised: 08/11/2003] [Accepted: 08/15/2003] [Indexed: 12/23/2022] Open
Abstract
Fragments of fibronectin (FN) corresponding to the N-terminal heparin-binding domain have been observed to promote catabolic chondrocytic gene expression and chondrolysis. We therefore characterized FN species that include sequences from this domain in samples of arthritic synovial fluid using one-and two-dimensional (1D and 2D) Western blot analysis. We detected similar assortments of species, ranging from ~47 to greater than 200 kDa, in samples obtained from patients with osteoarthritis (n = 9) versus rheumatoid arthritis (n = 10). One of the predominant forms, with an apparent molecular weight of ~170 kDa, typically resolved in 2D electrophoresis into a cluster of subspecies. These exhibited reduced binding to gelatin in comparison with a more prevalent species of ~200+ kDa and were also recognized by a monoclonal antibody to the central cell-binding domain (CBD). When considered together with our previous analyses of synovial fluid FN species containing the alternatively spliced EIIIA segment, these observations indicate that the ~170-kDa species includes sequences from four FN domains that have previously, in isolation, been observed to promote catabolic responses by chondrocytes in vitro: the N-terminal heparin-binding domain, the gelatin-binding domain, the central CBD, and the EIIIA segment. The ~170-kDa N-terminal species of FN may therefore be both a participant in joint destructive processes and a biomarker with which to gauge activity of the arthritic process.
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Affiliation(s)
- John H Peters
- Department of Internal Medicine, University of California, Davis School of Medicine, Davis, CA, USA.
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Peters JH, Loredo GA, Benton HP. Is osteoarthritis a 'fibronectin-integrin imbalance disorder'? Osteoarthritis Cartilage 2002; 10:831-5. [PMID: 12435325 DOI: 10.1053/joca.2002.0845] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Liao YF, Gotwals PJ, Koteliansky VE, Sheppard D, Van De Water L. The EIIIA segment of fibronectin is a ligand for integrins alpha 9beta 1 and alpha 4beta 1 providing a novel mechanism for regulating cell adhesion by alternative splicing. J Biol Chem 2002; 277:14467-74. [PMID: 11839764 DOI: 10.1074/jbc.m201100200] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alternative splicing of the fibronectin gene transcript gives rise to forms that include the EIIIA (or ED-A) segment. EIIIA-containing fibronectins are prominently expressed during embryogenesis and wound healing and appear to mediate changes in cell adhesion and gene expression. Nonetheless, integrins that bind the EIIIA segment have not been identified. We previously mapped the epitope for two function-blocking monoclonal antibodies to the C-C' loop region of the EIIIA segment (Liao, Y.-F., Wieder, K. G., Classen, J. M., and Van De Water, L. (1999) J. Biol. Chem. 274, 17876-17884). The sequence of this epitope ((39)PEDGIHELFP(48)) resembles the sequence within tenascin-C to which the integrin alpha(9)beta(1) binds. We now report that either integrin alpha(9)beta(1) or alpha(4)beta(1) can mediate cell adhesion to the EIIIA segment. Moreover, this interaction is blocked both by epitope-mapped EIIIA antibodies as well as by the respective anti-integrins. Deletion mutants of the EIIIA segment that include the C-C' loop and flanking sequence bind cells expressing either alpha(9)beta(1) or alpha(4)beta(1). Adhesion of alpha(4)beta(1)-containing MOLT-3 cells to the EIIIA segment stimulates phosphorylation of p44/42 MAP kinase. Our observation that two integrins bind the EIIIA segment establishes a novel mechanism by which cell adhesion to fibronectin is regulated by alternative splicing.
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Affiliation(s)
- Yung-Feng Liao
- Center for Engineering in Medicine and Surgical Service, Massachusetts General Hospital and Harvard Medical School, the Shriners Burns Hospital, Boston, Massachusetts 02114, USA
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