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Hosszu KK, Valentino A, Peerschke EI, Ghebrehiwet B. SLE: Novel Postulates for Therapeutic Options. Front Immunol 2020; 11:583853. [PMID: 33117397 PMCID: PMC7575694 DOI: 10.3389/fimmu.2020.583853] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/10/2020] [Indexed: 12/19/2022] Open
Abstract
Genetic deficiency in C1q is a strong susceptibility factor for systemic lupus erythematosus (SLE). There are two major hypotheses that potentially explain the role of C1q in SLE. The first postulates that C1q deficiency abrogates apoptotic cell clearance, leading to persistently high loads of potentially immunogenic self-antigens that trigger autoimmune responses. While C1q undoubtedly plays an important role in apoptotic clearance, an essential biological process such as removal of self- waste is so critical for host survival that multiple ligand-receptor combinations do fortunately exist to ensure that proper disposal of apoptotic debris is accomplished even in the absence of C1q. The second hypothesis is based on the observation that locally synthesized C1q plays a critical role in regulating the earliest stages of monocyte to dendritic cell (DC) differentiation and function. Indeed, circulating C1q has been shown to keep monocytes in a pre-dendritic state by silencing key molecular players and ensuring that unwarranted DC-driven immune responses do not occur. Monocytes are also able to display macromolecular C1 on their surface, representing a novel mechanism for the recognition of circulating "danger." Translation of this danger signal in turn, provides the requisite "license" to trigger a differentiation pathway that leads to adaptive immune response. Based on this evidence, the second hypothesis proposes that deficiency in C1q dysregulates monocyte-to-DC differentiation and causes inefficient or defective maintenance of self-tolerance. The fact that C1q receptors (cC1qR and gC1qR) are also expressed on the surface of both monocytes and DCs, suggests that C1q/C1qR may regulate DC differentiation and function through specific cell-signaling pathways. While their primary ligand is C1q, C1qRs can also independently recognize a vast array of plasma proteins as well as pathogen-associated molecular ligands, indicating that these molecules may collaborate in antigen recognition and processing, and thus regulate DC-differentiation. This review will therefore focus on the role of C1q and C1qRs in SLE and explore the gC1qR/C1q axis as a potential target for therapy.
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Affiliation(s)
- Kinga K Hosszu
- Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Alisa Valentino
- Department of Lab Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Ellinor I Peerschke
- Department of Lab Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Berhane Ghebrehiwet
- The Department of Medicine, Stony Brook University, Stony Brook, NY, United States
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2
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Anti gC1qR/p32/HABP1 Antibody Therapy Decreases Tumor Growth in an Orthotopic Murine Xenotransplant Model of Triple Negative Breast Cancer. Antibodies (Basel) 2020; 9:antib9040051. [PMID: 33036212 PMCID: PMC7709104 DOI: 10.3390/antib9040051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/18/2020] [Accepted: 09/08/2020] [Indexed: 01/09/2023] Open
Abstract
gC1qR is highly expressed in breast cancer and plays a role in cancer cell proliferation. This study explored therapy with gC1qR monoclonal antibody 60.11, directed against the C1q binding domain of gC1qR, in a murine orthotopic xenotransplant model of triple negative breast cancer. MDA231 breast cancer cells were injected into the mammary fat pad of athymic nu/nu female mice. Mice were segregated into three groups (n = 5, each) and treated with the vehicle (group 1) or gC1qR antibody 60.11 (100 mg/kg) twice weekly, starting at day 3 post-implantation (group 2) or when the tumor volume reached 100 mm3 (group 3). At study termination (d = 35), the average tumor volume in the control group measured 895 ± 143 mm3, compared to 401 ± 48 mm3 and 701 ± 100 mm3 in groups 2 and 3, respectively (p < 0.05). Immunohistochemical staining of excised tumors revealed increased apoptosis (caspase 3 and TUNEL staining) in 60.11-treated mice compared to controls, and decreased angiogenesis (CD31 staining). Slightly decreased white blood cell counts were noted in 60.11-treated mice. Otherwise, no overt toxicities were observed. These data are the first to demonstrate an in vivo anti-tumor effect of 60.11 therapy in a mouse model of triple negative breast cancer.
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Ghebrehiwet B, Geisbrecht BV, Xu X, Savitt AG, Peerschke EIB. The C1q Receptors: Focus on gC1qR/p33 (C1qBP, p32, HABP-1) 1. Semin Immunol 2019; 45:101338. [PMID: 31744753 DOI: 10.1016/j.smim.2019.101338] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 10/24/2019] [Accepted: 10/24/2019] [Indexed: 10/25/2022]
Abstract
In the past several years, a number of C1q binding surface proteins or receptors have been described. This is not of course surprising considering the complexity of the C1q molecule and its ability to bind to a wide range of cellular and plasma proteins via both its collagen-like [cC1q] region and its heterotrimeric globular heads [gC1q] each of which in turn is capable of binding a specific ligand. However, while each of these "receptor" molecules undoubtedly plays a specific function within its restricted microenvironment, and therefore merits full attention, this review nonetheless, will singularly focus on the structure and function of gC1qR-a multi-functional and multi-compartmental protein, which plays an important role in inflammation, infection, and cancer. Although first identified as a receptor for C1q, gC1qR has been shown to bind to a plethora of proteins found in plasma, on the cell surface and on pathogenic microorganisms. The plasma proteins that bind to gC1qR are mostly blood coagulation proteins and include high molecular weight kininogen [HK], Factor XII [Hageman factor], fibrinogen, thrombin [FII], and multimeric vitronectin. This suggests that gC1qR can play an important role in modulating not only of fibrin formation, particularly at local sites of immune injury and/or inflammation, but by activating the kinin/kallikrein system, it is also able to generate, bradykinin, a powerful vasoactive peptide that is largely responsible for the swelling seen in angioedema. Another important function of gC1qR is in cancer, where it has been shown to play a role in tumor cell survival, growth and metastatic invasion by interacting with critical molecules in the tumor cell microenvironment including those of the complement system and kinin system. Finally, by virtue of its ability to interact with a growing list of pathogen-associated molecules, including bacterial and viral ligands, gC1qR is becoming recognized as an important pathogen recognition receptor [PRR]. Given the numerous roles it plays in a growing list of disease settings, gC1qR has now become a potential target for the development of monoclonal antibody-based and/or small molecule-based therapies.
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Affiliation(s)
- Berhane Ghebrehiwet
- The Departments of Medicine, Stony Brook University, Stony Brook, NY 11794-8161 USA.
| | - Brian V Geisbrecht
- Kansas State University, Department of Biochemistry and Molecular Biophysics Manhattan, KS 66506 USA
| | - Xin Xu
- Kansas State University, Department of Biochemistry and Molecular Biophysics Manhattan, KS 66506 USA
| | - Anne G Savitt
- The Departments of Medicine, Stony Brook University, Stony Brook, NY 11794-8161 USA
| | - Ellinor I B Peerschke
- The Department of Laboratory Medicine, Memorial Sloan-Kettering Cancer Center, New York, 10065, USA
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4
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C1q as an autocrine and paracrine regulator of cellular functions. Mol Immunol 2016; 84:26-33. [PMID: 27914690 DOI: 10.1016/j.molimm.2016.11.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 12/20/2022]
Abstract
Most of the complement proteins in circulation are, by and large, synthesized in the liver. However data accumulated over the past several decades provide incontrovertible evidence that some if not most of the individual complement proteins are also synthesized extrahepatically by activated as well as non-activated cells. The question that is finally being addressed by various investigators is: are the locally synthesized proteins solely responsible for the myriad of biological functions in situ without the contribution of systemic complement? The answer is probably "yes". Among the proteins that are synthesized locally, C1q takes center stage for several reasons. First, it is synthesized predominantly by potent antigen presenting cells such as monocytes, macrophages and dendritic cells (DCs), which by itself is a clue that it plays an important role in antigen presentation and/or DC maturation. Second, it is transiently anchored on the cell surface via a transmembrane domain located in its A chain before it is cleaved off and released into the pericellular milieu. The membrane-associated C1q in turn, is able to sense danger patterns via its versatile antigen-capturing globular head domains. More importantly, locally synthesized C1q has been shown to induce a plethora of biological functions through the induction of immunomodulatory molecules by an autocrine- or paracrine- mediated signaling in a manner that mimics those of TNFα. These include recognition of pathogen- and danger- associated molecular patterns, phagocytosis, angiogenesis, apoptosis and induction of cytokines or chemokines that are important in modulating the inflammatory response. The functional convergence between C1q and TNFα in turn is attributed to their shared genetic ancestry. In this paper, we will infer to the aforementioned "local-synthesis-for-local function" paradigm using as an example, the role played by locally synthesized C1q in autoimmunity in general and in systemic lupus erythematosus in particular.
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Madhukaran SP, Alhamlan FS, Kale K, Vatish M, Madan T, Kishore U. Role of collectins and complement protein C1q in pregnancy and parturition. Immunobiology 2016; 221:1273-88. [PMID: 27349595 DOI: 10.1016/j.imbio.2016.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/27/2016] [Accepted: 06/09/2016] [Indexed: 12/18/2022]
Abstract
Collectins such as surfactant proteins SP-A, SP-D, and mannan-binding lectin (MBL), as well as complement protein C1q are evolutionarily conserved innate immune molecules. They are known to opsonize a range of microbial pathogens (bacteria, fungi, virus, and parasites) and trigger effector clearance mechanisms involving phagocytosis and/or complement activation. Collectins and C1q have also attracted attention in studies involving pregnancy as they are expressed in the female reproductive tissues during pregnancy; a unique state of immune suppression with increased susceptibility to infectious diseases. Recent studies are beginning to unravel their functional significance in implantation, placentation, pregnancy maintenance and parturition in normal and adverse pregnancies. Collectins and C1q, expressed in gestational tissues during pregnancy, might alter the status of mother's immune response to the allogenic fetus and the microenvironment, thereby serving as important regulators of fetus-mother interaction. Here, we discuss the functional roles that have been assigned to SP-A, SP-D, MBL and C1q in pregnancy and parturition.
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Affiliation(s)
- Shanmuga Priyaa Madhukaran
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, United Kingdom; Centre for Biotechnology and Bioinformatics, School of Life Sciences, Jawaharlal Nehru Institute for Advanced Studies, Secunderabad, Telangana, India
| | - Fatimah S Alhamlan
- Department of Infection and Immunity, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Kavita Kale
- Department of Innate Immunity, National Institute for Research in Reproductive Health (ICMR), Mumbai 400 012, India
| | - Manu Vatish
- Nuffield Department of Obstetrics & Gynaecology, University of Oxford, Oxford, OX3 9DU, United Kingdom
| | - Taruna Madan
- Department of Innate Immunity, National Institute for Research in Reproductive Health (ICMR), Mumbai 400 012, India
| | - Uday Kishore
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, United Kingdom.
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Toubai T, Guoqing H, Rossi C, Mathewson N, Oravecz-Wilson K, Cummings E, Wu J, Sun Y, Choi S, Reddy P. Ikaros deficiency in host hematopoietic cells separates GVL from GVHD after experimental allogeneic hematopoietic cell transplantation. Oncoimmunology 2015; 4:e1016699. [PMID: 26140241 PMCID: PMC4485841 DOI: 10.1080/2162402x.2015.1016699] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/02/2015] [Accepted: 02/03/2015] [Indexed: 10/25/2022] Open
Abstract
The graft-versus-leukemia (GVL) effect following allogeneic hematopoietic stem cell transplantation (allo-HCT) is critical for its curative potential. Hwever, GVL is tightly linked to graft-versus-host disease (GVHD). Among hematological malignancies, acute lymphoblastic leukemia (ALL) is the most resistant to GVL, although the reasons for this remain poorly understood. Clinical studies have identified alterations in Ikaros (Ik) transcription factor as the major marker associated with poor outcomes in ALL. We have shown that the absence of Ik in professional host-derived hematopoietic antigen-presenting cells (APCs) exacerbates GVHD. However, whether Ik expression plays a role in resistance to GVL is not known. In this study we used multiple clinically relevant murine models of allo-HCT to explore whether Ik expression in hematopoietic APCs and/or leukemic cells is critical for increasing resistance to GVL and thus inducing relapse. We found that Ik deficiency in host APCs failed to enhance GVL despite increased GVHD severity. Mechanistic studies with bone marrow (BM) chimeras and tetramer analyses demonstrated reduced tumor-specific immunodominant (gag+) antigen responses in the [B6Ik-/-→B6] group. Loss of GVL was observed when both the leukemia cells and the host APCs were deficient in Ik. We found that calreticulin (CRT) expression in host antigen-presenting dendritic cells (DCs) of Ik-/- animals was significantly lower than in wild-type animals. Rescuing CRT expression in Ik-/- DCs improved leukemic-specific cytotoxic T cell function. Together, our data demonstrate that the absence of Ikaros in host hematopoietic cells promotes resistance to GVL despite increasing GVHD and thus provides a potential mechanism for the poor outcome of Ik-/- ALL patients.
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Key Words
- 51Cr, Chromium-51
- ALL, acute lymphoblastic leukemia
- APC, allophycocyanin
- APCs, antigen-presenting cells
- Allo-HCT, allogeneic hematopoietic stem cell transplantation
- BC, blast crisis
- BLI, bioluminescence imaging
- BM, bone marrow
- BMDCs, bone marrow derived dendritic cells
- BMT, bone marrow transplantation
- CML, chronic myeloid leukemia
- CRT, calreticulin
- CTL, cytotoxic T cell
- DCs, dendritic cells
- FACS, Fluorescence-activated cell sorting
- FBS, fatal bovine serum
- FITC, fluorescein isothiocyanate
- GVHD, graft-versus-host-disease
- GVL, graft-versus-leukemia
- HCT, hematopoietic stem cell transplantation
- ICAM-1, intracellular adhesion molecule 1
- Ik DN, Ikaros dominant negative
- Ik, Ikaros
- Ikaros
- MACS, magnetic- activated cell sorting
- MBL-2, moloney-murine sarcoma virus-induced MBL-2 lymphoma cells
- MHC, major histocompatibility complex
- MLR, mixed lymphocyte reaction
- MiHAs, multiple minor histocompatibility antigens
- PBS, phosphate buffered saline
- PE, phycoerythrin
- SIRP-α, signal regulatory protein α
- TCD-BM, T cell depleted bone marrow
- TSA, tumor specific antigen
- Tregs, regulatory T cells
- UCUCA, University Committee on Use and Care of Animals
- WT, wild-type
- antigen-presenting cells
- bone marrow transplantation
- graft-versus-leukemia
- luc+, luciferase+
- mAbs, monoclonal antibodies
- mCRT, murine calreticulin
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Affiliation(s)
- Tomomi Toubai
- Department of Internal Medicine; University of Michigan Comprehensive Cancer Center ; Ann Arbor, MI USA
| | - Hou Guoqing
- Department of Pediatrics and Communicable Diseases; University of Michigan Medical School ; Ann Arbor, MI USA
| | - Corrine Rossi
- Department of Internal Medicine; University of Michigan Comprehensive Cancer Center ; Ann Arbor, MI USA
| | - Nathan Mathewson
- Department of Internal Medicine; University of Michigan Comprehensive Cancer Center ; Ann Arbor, MI USA
| | - Katherine Oravecz-Wilson
- Department of Internal Medicine; University of Michigan Comprehensive Cancer Center ; Ann Arbor, MI USA
| | - Emily Cummings
- Department of Internal Medicine; University of Michigan Comprehensive Cancer Center ; Ann Arbor, MI USA
| | - Julia Wu
- Department of Internal Medicine; University of Michigan Comprehensive Cancer Center ; Ann Arbor, MI USA
| | - Yaping Sun
- Department of Internal Medicine; University of Michigan Comprehensive Cancer Center ; Ann Arbor, MI USA
| | - Sung Choi
- Department of Pediatrics and Communicable Diseases; University of Michigan Medical School ; Ann Arbor, MI USA
| | - Pavan Reddy
- Department of Internal Medicine; University of Michigan Comprehensive Cancer Center ; Ann Arbor, MI USA
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7
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Ghebrehiwet B, Hosszu KK, Valentino A, Ji Y, Peerschke EIB. Monocyte Expressed Macromolecular C1 and C1q Receptors as Molecular Sensors of Danger: Implications in SLE. Front Immunol 2014; 5:278. [PMID: 25018754 PMCID: PMC4071343 DOI: 10.3389/fimmu.2014.00278] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 05/28/2014] [Indexed: 01/07/2023] Open
Abstract
The ability of circulating blood monocytes to express C1q receptors (cC1qR and gC1qR) as well as to synthesize and secrete the classical pathway proteins C1q, C1r, and C1s and their regulator, C1-INH is very well established. What is intriguing, however, is that, in addition to secretion of the individual C1 proteins monocytes are also able to display macromolecular C1 on their surface in a manner that is stable and functional. The cell surface C1 complex is presumably formed by a Ca2+-dependent association of the C1r2⋅C1s2 tetramer to C1q, which in turn is anchored via a membrane-binding domain located in the N-terminus of its A-chain as shown previously. Monocytes, which circulate in the blood for 1–3 days before they move into tissues throughout the body, not only serve as precursors of macrophages and dendritic cells (DCs), but also fulfill three main functions in the immune system: phagocytosis, antigen presentation, and cytokine production. Since the globular heads of C1q within the membrane associated C1 are displayed outwardly, we hypothesize that their main function – especially in circulating monocytes – is to recognize and capture circulating immune complexes or pathogen-associated molecular patterns in the blood. This in turn may give crucial signal, which drives the monocytes to migrate into tissues, differentiate into macrophages or DCs, and initiate the process of antigen elimination. Unoccupied C1q on the other hand may serve to keep monocytes in a pre-dendritic phenotype by silencing key molecular players thus ensuring that unwarranted DC-driven immune response does not occur. In this paper, we will discuss the role of monocyte/DC-associated C1q receptors, macromolecular C1 as well as secreted C1q in both innate and acquired immune responses.
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Affiliation(s)
- Berhane Ghebrehiwet
- Departments of Medicine and Pathology, Stony Brook University , Stony Brook, NY , USA
| | - Kinga K Hosszu
- Departments of Medicine and Pathology, Stony Brook University , Stony Brook, NY , USA
| | - Alisa Valentino
- Departments of Medicine and Pathology, Stony Brook University , Stony Brook, NY , USA
| | - Yan Ji
- Departments of Medicine and Pathology, Stony Brook University , Stony Brook, NY , USA
| | - Ellinor I B Peerschke
- Departments of Laboratory Medicine, Memorial Sloan-Kettering Cancer Center, and Laboratory Medicine and Pathology, Weill-Cornell Medical College , New York, NY , USA
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Rate A, Bosco A, McKenna KL, Holt PG, Upham JW. Airway epithelial cells condition dendritic cells to express multiple immune surveillance genes. PLoS One 2012; 7:e44941. [PMID: 22984588 PMCID: PMC3439377 DOI: 10.1371/journal.pone.0044941] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 08/14/2012] [Indexed: 01/18/2023] Open
Abstract
Increasing evidence suggests that crosstalk between airway epithelial cells (AEC) and adjacent dendritic cells (DC) tightly regulates airway mucosal DC function in steady state. AEC are known to express multiple immmuno-modulatory factors, though detailed information on how this influences human DC function remains incomplete. We recently demonstrated using an in vitro coculture model that AEC alter differentiation of monocytes into DC in a manner that inhibits expression of potentially damaging Th2 effector function. In the current study, we have extended these findings to examine other aspects of DC function. Using micro-array technology we show that multiple genes important for immune surveillance are significantly over expressed in purified AEC-conditioned DC, compared to control DC. These findings were confirmed by quantitative real time PCR or flow cytometry in an independent sample set. In particular, AEC-conditioned DC showed selective upregulation of chemokines that recruit Th1 cells, but minimal change in chemokines linked to Th2 cell recruitment. AEC-conditioned DC were also characterized by enhanced expression of complement family genes (C1QB, C2, CD59 and SERPING1), Fcγ receptor genes (FCGR1A, FCGR2A, FCGR2B and FCGR2C), signaling lymphocytic activation molecule family member 1 (SLAM), programmed death ligands 1 and 2, CD54 and CD200R1, relative to control DC. These findings suggest that AEC conditioning facilitates the capacity of DC to react to danger signals, to enhance leukocyte recruitment, especially of Th1 effector cells, and to interact with other immune cell populations while minimizing the risks of excessive inflammation leading to tissue damage.
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Affiliation(s)
- Angela Rate
- Telethon Institute for Child Health Research, and Centre for Child Health Research, The University of Western Australia, Perth, Western Australia, Australia
| | - Anthony Bosco
- Telethon Institute for Child Health Research, and Centre for Child Health Research, The University of Western Australia, Perth, Western Australia, Australia
| | - Kathy L. McKenna
- Telethon Institute for Child Health Research, and Centre for Child Health Research, The University of Western Australia, Perth, Western Australia, Australia
| | - Patrick G. Holt
- Telethon Institute for Child Health Research, and Centre for Child Health Research, The University of Western Australia, Perth, Western Australia, Australia
| | - John W. Upham
- School of Medicine, The University of Queensland, Brisbane, Queensland, Australia
- * E-mail:
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DC-SIGN, C1q, and gC1qR form a trimolecular receptor complex on the surface of monocyte-derived immature dendritic cells. Blood 2012; 120:1228-36. [PMID: 22700724 DOI: 10.1182/blood-2011-07-369728] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
C1q modulates the differentiation and function of cells committed to the monocyte-derived dendritic cell (DC) lineage. Because the 2 C1q receptors found on the DC surface-gC1qR and cC1qR-lack a direct conduit into intracellular elements, we postulated that the receptors must form complexes with transmembrane partners. In the present study, we show that DC-SIGN, a C-type lectin expressed on DCs, binds directly to C1q, as assessed by ELISA, flow cytometry, and immunoprecipitation experiments. Surface plasmon resonance analysis revealed that the interaction was specific, and both intact C1q and the globular portion of C1q bound to DC-SIGN. Whereas IgG reduced this binding significantly, the Arg residues (162-163) of the C1q-A chain, which are thought to contribute to the C1q-IgG interaction, were not required for C1q binding to DC-SIGN. Binding was reduced significantly in the absence of Ca(2+) and by preincubation of DC-SIGN with mannan, suggesting that C1q binds to DC-SIGN at its principal Ca(2+)-binding pocket, which has increased affinity for mannose residues. Antigen-capture ELISA and immunofluorescence microscopy revealed that C1q and gC1qR associate with DC-SIGN on blood DC precursors and immature DCs. The results of the present study suggest that C1q/gC1qR may regulate DC differentiation and function through the DC-SIGN-mediated induction of cell-signaling pathways.
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10
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Hosszu KK, Valentino A, Ji Y, Matkovic M, Pednekar L, Rehage N, Tumma N, Peerschke EIB, Ghebrehiwet B. Cell surface expression and function of the macromolecular c1 complex on the surface of human monocytes. Front Immunol 2012; 3:38. [PMID: 22566921 PMCID: PMC3342062 DOI: 10.3389/fimmu.2012.00038] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 02/16/2012] [Indexed: 11/13/2022] Open
Abstract
The synthesis of the subunits of the C1 complex (C1q, C1s, C1r), and its regulator C1 inhibitor (C1-Inh) by human monocytes has been previously established. However, surface expression of these molecules by monocytes has not been shown. Using flow cytometry and antigen-capture enzyme-linked immunosorbent assay, we show here for the first time that, in addition to C1q, peripheral blood monocytes, and the monocyte-derived U937 cells express C1s and C1r, as well as Factor B and C1-Inh on their surface. C1s and C1r immunoprecipitated with C1q, suggesting that at least some of the C1q on these cells is part of the C1 complex. Furthermore, the C1 complex on U937 cells was able to trigger complement activation via the classical pathway. The presence of C1-Inh may ensure that an unwarranted autoactivation of the C1 complex does not take place. Since C1-Inh closely monitors the activation of the C1 complex in a sterile or infectious inflammatory environment, further elucidation of the role of C1 complex is crucial to dissect its function in monocyte, dendritic cell, and T cell activities, and its implications in host defense and tolerance.
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Affiliation(s)
- Kinga K Hosszu
- The Department of Medicine, Stony Brook University Stony Brook, NY, USA
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11
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Ghebrehiwet B, Hosszu KK, Valentino A, Peerschke EIB. The C1q family of proteins: insights into the emerging non-traditional functions. Front Immunol 2012; 3. [PMID: 22536204 PMCID: PMC3334295 DOI: 10.3389/fimmu.2012.00052] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Research conducted over the past 20 years have helped us unravel not only the hidden structural and functional subtleties of human C1q, but also has catapulted the molecule from a mere recognition unit of the classical pathway to a well-recognized molecular sensor of damage-modified self or non-self antigens. Thus, C1q is involved in a rapidly expanding list of pathological disorders – including autoimmunity, trophoblast migration, preeclampsia, and cancer. The results of two recent reports are provided to underscore the critical role C1q plays in health and disease. First is the observation by Singh et al. (2011) showing that pregnant C1q−/− mice recapitulate the key features of human preeclampsia that correlate with increased fetal death. Treatment of the C1q−/− mice with pravastatin restored trophoblast invasiveness, placental blood flow, and angiogenic balance and, thus, prevented the onset of preeclampsia. Second is the report by Hong et al. (2009) which showed that C1q can induce apoptosis of prostate cancer cells by activating the tumor suppressor molecule WW-domain containing oxydoreductase (WWOX or WOX1) and destabilizing cell adhesion. Downregulation of C1q on the other hand, enhanced prostate hyperplasia and cancer formation due to failure of WOX1 activation. C1q belongs to a family of structurally and functionally related TNF-α-like family of proteins that may have arisen from a common ancestral gene. Therefore C1q not only shares the diverse functions with the tumor necrosis factor family of proteins, but also explains why C1q has retained some of its ancestral “cytokine-like” activities. This review is intended to highlight some of the structural and functional aspects of C1q by underscoring the growing list of its non-traditional functions.
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12
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Sánchez-Martín D, Cuesta AM, Fogal V, Ruoslahti E, Alvarez-Vallina L. The multicompartmental p32/gClqR as a new target for antibody-based tumor targeting strategies. J Biol Chem 2010; 286:5197-203. [PMID: 21156793 DOI: 10.1074/jbc.m110.161927] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Tumor-associated cell surface antigens and tumor-associated vascular markers have been used as a target for cancer intervention strategies. However, both types of targets have limitations due to accessibility, low and/or heterogeneous expression, and presence of tumor-associated serum antigen. It has been previously reported that a mitochondrial/cell surface protein, p32/gC1qR, is the receptor for a tumor-homing peptide, LyP-1, which specifically recognizes an epitope in tumor cells, tumor lymphatics, and tumor-associated macrophages/myeloid cells. Using antibody phage technology, we have generated an anti-p32 human monoclonal antibody (2.15). The 2.15 antibody, expressed in single-chain fragment variable and in trimerbody format, was then characterized in vivo using mice grafted subcutaneously with MDA-MB-231 human breast cancers cells, revealing a highly selective tumor uptake. The intratumoral distribution of the antibody was consistent with the expression pattern of p32 in the surface of some clusters of cells. These results demonstrate the potential of p32 for antibody-based tumor targeting strategies and the utility of the 2.15 antibody as targeting moiety for the selective delivery of imaging and therapeutic agents to tumors.
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Affiliation(s)
- David Sánchez-Martín
- Molecular Immunology Unit, Hospital Universitario Puerta de Hierro Majadahonda, 28222 Madrid, Spain
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13
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Kis-Toth K, Tsokos GC. Dendritic cell function in lupus: Independent contributors or victims of aberrant immune regulation. Autoimmunity 2010; 43:121-30. [PMID: 20102311 DOI: 10.3109/08916930903214041] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Dendritic cells (DCs) represent an important component of the immune system connecting the innate and adaptive immune responses. They are able to trigger strong immunity as well as tolerance against certain antigens, and therefore it is obvious that they have a central role in the expression of immunological diseases. However, because DCs are sparse, heterogeneous and plastic, their exact role in complex autoimmune diseases, such as systemic lupus erythematosus (SLE) remains not well defined. In this review, we make an attempt to summarize critically recent knowledge on the role of conventional DCs in the expression of autoimmunity and pathology in SLE.
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Affiliation(s)
- Katalin Kis-Toth
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
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14
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Hosszu KK, Santiago-Schwarz F, Peerschke EIB, Ghebrehiwet B. Evidence that a C1q/C1qR system regulates monocyte-derived dendritic cell differentiation at the interface of innate and acquired immunity. Innate Immun 2009; 16:115-27. [PMID: 19710097 DOI: 10.1177/1753425909339815] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Growing evidence shows that C1q modulates the growth and function of cells committed to the monocyte-derived dendritic cell (DC) lineage. Because C1q regulates both innate and acquired immune responses, we postulated that C1q modulates the transition from monocytes to DCs, i.e. the interface between innate and acquired immunity. Human peripheral blood monocytes cultured with soluble C1q and DC growth factors (granulocyte-macrophage colony-stimulating factor + Interleukin-4) failed to down-regulate monocyte-associated (CD14, CD16) and up-regulate DC-associated (CD83, CD86) markers. Impaired DC differentiation was not due to apoptosis; further analysis revealed the development of CD14(hi)CD11c(hi)CD16 (+/-) cells that have previously been associated with both innate and acquired immunity. Monocyte-DC precursors expressed gC1qR, the receptor for globular heads of C1q, from the outset, while cC1qR, the receptor for the collagen tails of C1q, was expressed at low levels. Notably, the binding pattern of monoclonal antibodies specific to the globular heads of C1q indicated that C1q is bound to monocytes via globular heads, presumably through gC1qR. Moreover, gC1qR levels decreased, while cC1qR levels were dramatically amplified as monocytes differentiated into immature DC. Thus, specific C1q/C1q receptor (R) interactions may control the transition from the monocyte state (innate immunity) toward the professional antigen-presenting cell state (adaptive immunity).
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Affiliation(s)
- Kinga K Hosszu
- Department of Medicine, Stony Brook University, Stony Brook, New York, USA
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15
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Flores-Langarica A, Sebti Y, Mitchell DA, Sim RB, MacPherson GG. Scrapie pathogenesis: the role of complement C1q in scrapie agent uptake by conventional dendritic cells. THE JOURNAL OF IMMUNOLOGY 2009; 182:1305-13. [PMID: 19155476 DOI: 10.4049/jimmunol.182.3.1305] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mice lacking complement components show delayed development of prion disease following peripheral inoculation. The delay could relate to reduced scrapie prion protein (PrP(Sc)) accumulation on follicular dendritic cells (DCs). However conventional DCs (cDCs) play a crucial role in the early pathogenesis of prion diseases and complement deficiency could result in decreased PrP(Sc) uptake by cDCs in the periphery. To explore this possibility, we cultured murine splenic or gut-associated lymph node cDCs with scrapie-infected whole brain homogenate in the presence or absence of complement. Uptake decreased significantly if the serum in the cultures was heat-inactivated. Because heat inactivation primarily denatures C1q, we used serum from C1q(-/-) mice and showed that PrP(Sc) uptake was markedly decreased. PrP(Sc) internalization was saturable and temperature-dependent, suggesting receptor-mediated uptake. Furthermore, uptake characteristics differed from fluid-phase endocytosis. Immunofluorescence showed colocalization of C1q and PrP(Sc), suggesting interaction between these molecules. We evaluated the expression of several complement receptors on cDCs and confirmed that cDCs that take up PrP(Sc) express one of the C1q receptors, calreticulin. Our results show that C1q participates in PrP(Sc) uptake by cDCs, revealing a critical role for cDCs in initial prion capture, an event that takes place before the PrP(Sc) accumulation within the follicular DC network.
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Affiliation(s)
- Adriana Flores-Langarica
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE Oxford, UK
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16
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Tahtouh M, Croq F, Vizioli J, Sautiere PE, Van Camp C, Salzet M, Daha MR, Pestel J, Lefebvre C. Evidence for a novel chemotactic C1q domain-containing factor in the leech nerve cord. Mol Immunol 2009; 46:523-31. [DOI: 10.1016/j.molimm.2008.07.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 07/15/2008] [Accepted: 07/15/2008] [Indexed: 10/21/2022]
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17
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C1q enhances IFN-gamma production by antigen-specific T cells via the CD40 costimulatory pathway on dendritic cells. Blood 2009; 113:3485-93. [PMID: 19171874 DOI: 10.1182/blood-2008-06-164392] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dendritic cells (DCs) are known to produce C1q, the initiator of the classical complement pathway. We demonstrate that murine DCs deficient in C1q (C1qa(-/-)) are poorer than wild-type (WT) DCs at eliciting the proliferation and Th1 differentiation of antigen-specific T cells. These defects result from decreased production of IL-12p70 by C1qa(-/-) DCs and impaired expression of costimulatory molecules CD80 and CD86 in response to CD40 ligation. The defective production of IL-12p70 and the reduced expression of CD80 and CD86 by C1qa(-/-) DCs were specifically mediated via CD40 ligation, as normal levels of IL-12p70 and CD80/86 were observed after ligation of Toll-like receptors (TLRs) on C1qa(-/-) DCs. CD40 ligation on C1qa(-/-) DCs, but not TLR ligation, results in decreased phosphorylation of p38 and ERK1/2 kinases. A strong colocalization of CD40 and C1q was observed by confocal microscopy upon CD40 ligation (but not TLR ligation) on DCs. Furthermore, human DCs from 2 C1q-deficient patients were found to have impaired IL-12p70 production in response to CD40L stimulation. Our novel data suggest that C1q augments the production of IL-12p70 by mouse and human DCs after CD40 triggering and plays important roles in sustaining the maturation of DCs and guiding the activation of T cells.
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18
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Handbook of experimental pharmacology "dendritic cells": the use of dexamethasone in the induction of tolerogenic DCs. Handb Exp Pharmacol 2009:233-49. [PMID: 19031029 DOI: 10.1007/978-3-540-71029-5_11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Dendritic cells (DCs) have a central role in immune regulation, ranging from tolerance induction to the induction of specific immune responses. DCs serve as an essential link between innate and adaptive immunity. This broad range of powerful immune stimulatory as well as regulatory functions has made DCs as targets for vaccine development strategies. One approach to promote the tolerogenicity of DCs is to suppress their maturation by pharmacological agents, including glucocorticoids (GCs). In the present chapter we will review GCs used in vitro with cultured DCs, applied in vivo, or used to generate tolerogenic DCs for cellular therapy.
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19
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van Kooten C, Fiore N, Trouw LA, Csomor E, Xu W, Castellano G, Daha MR, Gelderman KA. Complement production and regulation by dendritic cells: molecular switches between tolerance and immunity. Mol Immunol 2008; 45:4064-72. [PMID: 18926283 DOI: 10.1016/j.molimm.2008.07.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Accepted: 07/12/2008] [Indexed: 12/13/2022]
Abstract
In recent years it has become clear that the innate and adaptive immune systems are highly integrated and interact at several levels. Dendritic cells (DCs) are on the one hand instrumental for directing and controlling adaptive immunity and on the other hand are specialized in detecting and integrating signals from the microenvironment. In view of the strong link between deficiencies in certain complement components and the development of autoimmunity, interaction between complement and DCs seems to be of fundamental importance. We will discuss the role of C1q, C3, as well as complement regulators in DC biology.
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Affiliation(s)
- Cees van Kooten
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands.
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20
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Csencsits K, Burrell BE, Lu G, Eichwald EJ, Stahl GL, Bishop DK. The classical complement pathway in transplantation: unanticipated protective effects of C1q and role in inductive antibody therapy. Am J Transplant 2008; 8:1622-30. [PMID: 18557731 PMCID: PMC2587427 DOI: 10.1111/j.1600-6143.2008.02295.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Though complement (C) deposition within the transplant is associated with allograft rejection, the pathways employed have not been established. In addition, evidence suggests that C-mediated cytolysis may be necessary for the tolerance-inducing activities of mAb therapies. Hence, we assessed the role of the classical C pathway in acute allograft rejection and its requirement for experimental mAb therapies. C1q-deficient (C1q-/-) recipients rejected allografts at a faster rate than wild-type (WT) recipients. This rejection was associated with exacerbated graft pathology but not with enhanced T-cell responses in C1q-/- recipients. However, the humoral response to donor alloantigens was accelerated in C1q-/- mice, as an early IgG response and IgG deposition within the graft were observed. Furthermore, deposition of C3d, but not C4d was observed in grafts isolated from C1q-/- recipients. To assess the role of the classical C pathway in inductive mAb therapies, C1q-/- recipients were treated with anti-CD4 or anti-CD40L mAb. The protective effects of anti-CD4 mAb were reduced in C1q-/- recipients, however, this effect did not correlate with ineffective depletion of CD4+ cells. In contrast, the protective effects of anti-CD40L mAb were less compromised in C1q-/- recipients. Hence, this study reveals unanticipated roles for C1q in the rejection process.
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Affiliation(s)
- K. Csencsits
- Section of General Surgery, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI 48109,*Corresponding Author: Keri Csencsits, Ph.D., Department of Pathology and Laboratory Medicine, 2.250 MSB, 6431 Fannin, University of Texas Health Science Center at Houston, Houston, TX 77030, Phone: 713-500-7235//Fax: 713-500-0574,
| | - B. E. Burrell
- Graduate Program in Immunology, University of Michigan School of Medicine, Ann Arbor, MI 48109
| | - G. Lu
- Section of General Surgery, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI 48109
| | - E. J. Eichwald
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - G. L. Stahl
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115
| | - D. K. Bishop
- Section of General Surgery, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI 48109, Graduate Program in Immunology, University of Michigan School of Medicine, Ann Arbor, MI 48109
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21
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Biswas AK, Hafiz A, Banerjee B, Kim KS, Datta K, Chitnis CE. Plasmodium falciparum uses gC1qR/HABP1/p32 as a receptor to bind to vascular endothelium and for platelet-mediated clumping. PLoS Pathog 2007; 3:1271-80. [PMID: 17907801 PMCID: PMC2323294 DOI: 10.1371/journal.ppat.0030130] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Accepted: 07/23/2007] [Indexed: 01/11/2023] Open
Abstract
The ability of Plasmodium falciparum–infected red blood cells (IRBCs) to bind to vascular endothelium, thus enabling sequestration in vital host organs, is an important pathogenic mechanism in malaria. Adhesion of P. falciparum IRBCs to platelets, which results in the formation of IRBC clumps, is another cytoadherence phenomenon that is associated with severe disease. Here, we have used in vitro cytoadherence assays to demonstrate, to our knowledge for the first time, that P. falciparum IRBCs use the 32-kDa human protein gC1qR/HABP1/p32 as a receptor to bind to human brain microvascular endothelial cells. In addition, we show that P. falciparum IRBCs can also bind to gC1qR/HABP1/p32 on platelets to form clumps. Our study has thus identified a novel host receptor that is used for both adhesion to vascular endothelium and platelet-mediated clumping. Given the association of adhesion to vascular endothelium and platelet-mediated clumping with severe disease, adhesion to gC1qR/HABP1/p32 by P. falciparum IRBCs may play an important role in malaria pathogenesis. Adhesion of Plasmodium falciparum–infected red blood cells (IRBCs) to the endothelium lining the capillaries of vital host organs can obstruct blood circulation and is an important pathogenic mechanism in malaria. Adhesion of P. falciparum IRBCs to platelets results in the formation of IRBC clumps that can also obstruct blood flow and is implicated in severe malaria. Here, we have identified a novel cytoadherence receptor that is found on both endothelial cells and platelets. We demonstrate, for the first time to our knowledge, that P. falciparum IRBCs use the 32-kDa human protein gC1qR/HABP1/p32 as a receptor to bind to human endothelial cells, including brain microvascular endothelial cells. In addition, we show that P. falciparum IRBCs can bind to gC1qR/HABP1/p32 on platelets to form clumps. Our study has thus identified a novel host receptor that is used for both adhesion to vascular endothelium and platelet-mediated clumping. Given the association of these cytoadherence phenomena with severe disease, our study opens the door to investigations on the role of adhesion of P. falciparum IRBCs to gC1qR/HABP1/p32 in malaria pathogenesis.
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Affiliation(s)
- Anup Kumar Biswas
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Abdul Hafiz
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Bhaswati Banerjee
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Kwang Sik Kim
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Kasturi Datta
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
- * To whom correspondence should be addressed. E-mail: (KD); (CEC)
| | - Chetan E Chitnis
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- * To whom correspondence should be addressed. E-mail: (KD); (CEC)
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Ghebrehiwet B, CebadaMora C, Tantral L, Jesty J, Peerschke EIB. gC1qR/p33 serves as a molecular bridge between the complement and contact activation systems and is an important catalyst in inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 586:95-105. [PMID: 16893067 DOI: 10.1007/0-387-34134-x_7] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The receptor for the globular heads of C1q, gC1qR/p33, is a ubiquitously expressed protein, which is distributed both intracellularly and on the cell-surface protein. In addition to C1q, this molecule also is able to bind several other biologically important plasma ligands, including high-molecular-weight kininogen (HK), factor XII (FXII), and multimeric vitronectin. Previous studies have shown that incubation of FXII, prekallikrein, and HK with gC1qR leads to a zinc-dependent and FXII-dependent conversion of prekallikrein to kallikrein, a requisite for kinin generation. In addition, these studies showed that normal plasma, but not plasma deficient in FXII, PK, or HK, activate upon binding to endothelial cells (EC), and that this activation could be inhibited by antibody to gClqR. In these studies, we show that incubation of serum with microtiter plate bound gC1qR results in complement activation, as evidenced by the binding and activation of C1 and generation of C4d. However, neither Clq-deficient serum nor a truncated form of gC1qR (gC1qRA74-96), supported complement activation. Taken together, the data strongly suggest that at sites of inflammation, such as vasculitis and atherosclerosis, where gC1qR as well as its two important plasma ligands, C1q and HK, have been shown to be simultaneously present, soluble or cell-surface-expressed gC1qR may contribute to the inflammatory process by modulating complement activation, kinin generation, and perhaps even initiation of clotting via the contact system. Based on these and other published data, we propose a model of inflammation in which atherogenic factors (e.g., immune complexes, virus, or bacteria) are perceived not only to convert the endothelium into a procoagulant and proinflammatory surface, but also to induce enhanced expression of cell surface molecules such as gC1qR. Enhanced expression of gC1qR in turn leads to: (i) high-affinity C1q binding and cell production of proinflammatory factors, and (ii) high-affinity HK binding and facilitation of the assembly of contact activation proteins leading to generation of bradykinin and possibly coagulation through activation of FXI.
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23
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Bajtay Z, Csomor E, Sándor N, Erdei A. Expression and role of Fc- and complement-receptors on human dendritic cells. Immunol Lett 2006; 104:46-52. [PMID: 16448704 DOI: 10.1016/j.imlet.2005.11.023] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Revised: 11/22/2005] [Accepted: 11/22/2005] [Indexed: 10/25/2022]
Abstract
Dendritic cells (DCs) are professional antigen presenting cells, which take up pathogens/foreign structures in peripheral tissues, then migrate to secondary lymphoid organs where they initiate adaptive immune responses by activating naive T-cells. In the early phase of antigen uptake pattern recognition receptors (including mannose-, scavenger- and toll-like receptors) that recognize pathogen-associated molecular patterns play an important role. Later receptors binding opsonized antigen are also involved in phagocytosis. These cell membrane molecules include various Fc-receptors, recognizing different isotypes of antibodies and various complement-receptors, such as CR3, CR4 and the C1q-binding complex of calreticulin and CD91. Here we aim to summarize how these immunecomplex binding receptors are involved in the initiation of DC maturation, and how they influence antigen presentation as well as some additional functions of these cells.
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Affiliation(s)
- Zsuzsa Bajtay
- Department of Immunology, Eötvös Loránd University, Pázmány Peter s. 1/C, Budapest H-1117, Hungary
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24
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Fritz JH, Brunner S, Birnstiel ML, Buschle M, Gabain AV, Mattner F, Zauner W. The artificial antimicrobial peptide KLKLLLLLKLK induces predominantly a TH2-type immune response to co-injected antigens. Vaccine 2004; 22:3274-84. [PMID: 15308350 DOI: 10.1016/j.vaccine.2004.03.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2003] [Revised: 02/26/2004] [Accepted: 03/05/2004] [Indexed: 11/22/2022]
Abstract
Cationic antimicrobial peptides (CAMPs) are active defence components of the innate immune system. Several artificial CAMPs have been designed as antibiotic peptide therapeutics, but none have been reported to exert adjuvant activity in animal models. Here we show for the first time that an artificial CAMP, KLKLLLLLKLK (KLKL5KLK), is a potent inducer of adaptive immunity to co-injected antigens in vivo. High levels of antigen-specific antibodies were obtained after co-injection of KLKL5KLK with the model antigen ovalbumin (OVA) or a commercially available influenza vaccine. We show that KLKL5KLK induces a sustained immune response with a prevalent TH2 profile when co-injected with proteinaceous and peptide-based antigens. Furthermore, the immuno-enhancing activity of peptide KLKL5KLK was retained when C-terminally amidated or synthesised as retro-all-D-peptide. We provide evidence that KLKL5KLK enhances the association of antigen to antigen-presenting cells and forms a depot of antigen at the site of injection, making it an interesting adjuvant for novel vaccine design.
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Affiliation(s)
- Jörg H Fritz
- Intercell AG, Campus Vienna Biocenter 6, 1030 Vienna, Austria.
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