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Peng F, Zhang H, He X, Song Z. Early flora colonization affects intestinal immunoglobulin G uptake in piglets, which may be mediated by NF-κB-FcRn pathway. Front Microbiol 2023; 14:1136513. [PMID: 36865776 PMCID: PMC9971964 DOI: 10.3389/fmicb.2023.1136513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 01/23/2023] [Indexed: 02/16/2023] Open
Abstract
Introduction The passive immunity of newborn piglets is mainly derived from immunoglobulin G (IgG) in breast milk, and the incomplete transfer of passive immune is considered to be an important cause of piglet death. This study was conducted to investigate the effect of early intestinal flora colonization on IgG uptake and its possible mechanism. Methods The newborn piglets and IPEC-J2 cells were used to investigate the possible factors and regulatory mechanisms affecting intestinal IgG uptake. In vivo, all 40 piglets were euthanized on postnatal d 0, 1, 3, and 7, with 10 piglets per time. The blood sample, gastric contents, jejunal contents and mucosa were collected for analysis. In vitro, IPEC-J2 cells transwell culture system was used to establish the IgG transporter model to explore the specific regulatory mechanism of IgG transport. Results Our results demonstrated that the intestinal IgG uptake was positively correlated with the expression of Neonatal Fc receptor (FcRn). With the increase of age, the intestinal flora of newborn piglets was gradually enriched. The function of intestinal genes also changes with the colonization of intestinal flora. We found that the expression trend of TLR2, TLR4 and NF-κB (P65) in intestine was consistent with that of FcRn. Furthermore, the in vitro results demonstrate that the NF-κB signaling pathway is involved in regulating FcRn-mediated IgG transmembrane transport. Discussion Early flora colonization affects intestinal IgG uptake in piglets, which may be mediated by NF-κB-FcRn pathway.
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Affiliation(s)
- Fang Peng
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Haihan Zhang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Xi He
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
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TGEV infection up-regulates FcRn expression via activation of NF-κB signaling. Sci Rep 2016; 6:32154. [PMID: 27555521 PMCID: PMC4995372 DOI: 10.1038/srep32154] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/03/2016] [Indexed: 12/28/2022] Open
Abstract
It has been well characterized that the neonatal Fc receptor (FcRn) transports maternal IgG to a fetus or newborn and protects IgG from degradation. We previously reported that FcRn is expressed in a model of normal porcine intestinal epithelial cells (IPEC-J2). Transmissible gastroenteritis is an acute enteric disease of swine that is caused by transmissible gastroenteritis virus (TGEV). How porcine FcRn (pFcRn) expression is regulated by pathogenic infection remains unknown. Our research shows that IPEC-J2 cells infected with TGEV had up-regulated pFcRn expression. In addition, the NF-κB signaling pathway was activated in IPEC-J2 cells by TGEV infection. Furthermore, treatment of TGEV-infected IPEC-J2 cells with the NF-κB-specific inhibitor BAY 11-7082 resulted in down-regulation of pFcRn expression. Transient transfection of pFcRn promoter luciferase report plasmids with overexpression of NF-κB p65 transcription factor enhanced the activation of the luciferase report plasmids. We identified four NF-κB transcription factor binding sites in the promoter region of this gene using luciferase reporter system, chromatin immunoprecipitation, electromobility shift assay, and supershift analysis. Together, the data provide the first evidence that TGEV infection up-regulates pFcRn expression via activation of NF-κB signaling.
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Cervenak J, Kurrle R, Kacskovics I. Accelerating antibody discovery using transgenic animals overexpressing the neonatal Fc receptor as a result of augmented humoral immunity. Immunol Rev 2015; 268:269-87. [DOI: 10.1111/imr.12364] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | | | - Imre Kacskovics
- ImmunoGenes Ltd; Budakeszi Hungary
- Department of Immunology; Eötvös Loránd University; Budapest Hungary
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Mikulska JE. Analysis of Response Elements Involved in the Regulation of the Human Neonatal Fc Receptor Gene (FCGRT). PLoS One 2015; 10:e0135141. [PMID: 26252948 PMCID: PMC4529178 DOI: 10.1371/journal.pone.0135141] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 07/19/2015] [Indexed: 12/26/2022] Open
Abstract
Human epithelial, endothelial and PMA-differentiated THP-1 cell lines were used as model systems to study the transcriptional regulation of the human FCGRT gene encoding the alpha chain of hFcRn. The data obtained from site-directed mutagenesis in transient transfection experiments indicate that the Sp1 sites at positions -641, -635, and -313, CF1/YY1 elements at positions -586 and -357, and the AP-1 motif at -276 within the-660/-233 fragment of the human FCGRT promoter (hFCGRT) participate in the regulation of human FCGRT in all selected cell lines. However, their individual contribution to promoter activity is not equivalent. The Sp1 binding site at -313 and the AP-1 site at -276 are critical for the activity of the hFCGRT promoter in epithelial and endothelial cells. Moreover, the CF1/YY1 site at -586 in differentiated THP-1 cells, plays an essential role in the transcriptional activity of the promoter. In addition, the C/EBPbeta binding site at -497 of the hFCGRT promoter in epithelial and endothelial cells, and the C/EBPbeta motif located at -497 and -233 within the hFCGRT promoter in differentiated THP-1 cells may function as positive regulatory sequences in response to LPS or PMA stimulation. EMSA and supershift analyses showed that the functionally identified binding motifs in the hFCGRT promoter were able to specifically interact with their corresponding (Sp1, Sp2, Sp3, c-Fos, c-Jun, YY1, and C/EBPbeta or C/EBPdelta) transcription factors (TFs), suggesting their possible involvement in the regulation of the human FCGRT gene expression.
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Affiliation(s)
- Joanna E. Mikulska
- Department of Immunochemistry, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
- * E-mail:
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Cervenak J, Doleschall M, Bender B, Mayer B, Schneider Z, Doleschall Z, Zhao Y, Bősze Z, Hammarström L, Oster W, Kacskovics I. NFκB induces overexpression of bovine FcRn: a novel mechanism that further contributes to the enhanced immune response in genetically modified animals carrying extra copies of FcRn. MAbs 2015; 5:860-71. [PMID: 24492342 DOI: 10.4161/mabs.26507] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Among the many functions of the neonatal Fc receptor (FcRn) for IgG, it binds to IgG-opsonized antigen complexes and propagates their traffic into lysosomes where antigen processing occurs. We previously reported that transgenic (Tg) mice and rabbits that carry multiple copies and overexpress FcRn have augmented humoral immune responses. Nuclear factor-kappa B (NFκB) is a critical molecule in the signaling cascade in the immune response. NFκB induces human FcRn expression and our previous in silico analysis suggested NFκB binding sites in the promoter region of the bovine (b) FcRn α-chain gene (FCGRT). Here, we report the identification of three NFκB transcription binding sites in the promoter region of this gene using luciferase reporter gene technology, electromobility shift assay and supershift analysis. Stimulation of primary bovine endothelial cells with the Toll-like receptor-4 ligand lipopolysaccharide (LPS), which mediates its effect via NFκB, resulted in rapid upregulation of the bFcRn expression and a control gene, bovine E-selectin. This rapid bFcRn gene induction was also observed in the spleen of bFcRn Tg mice treated with intraperitoneally injected LPS, analyzed by northern blot analysis. Finally, NFκB-mediated bFcRn upregulation was confirmed at the protein level in macrophages isolated from the bFcRn Tg mice using flow cytometry with a newly developed FcRn specific monoclonal antibody that does not cross-react with the mouse FcRn. We conclude that NFκB regulates bFcRn expression and thus optimizes its functions, e.g., in the professional antigen presenting cells, and contributes to the much augmented humoral immune response in the bFcRn Tg mice.
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Affiliation(s)
| | - Márton Doleschall
- Molecular Medicine Research Group; Hungarian Academy of Sciences and Semmelweis University; Budapest, Hungary
| | | | - Balázs Mayer
- Department of Dermatology, Venereology, and Dermatooncology; Semmelweis University; Budapest, Hungary
| | - Zita Schneider
- Department of Immunology; Eötvös Loránd University; Budapest, Hungary
| | - Zoltán Doleschall
- Department of Pathogenetics; National Institute of Oncology; Budapest, Hungary
| | - Yaofeng Zhao
- State Key Laboratory of Agrobiotechnology; China Agricultural University; Beijing, China
| | | | - Lennart Hammarström
- Division of Clinical Immunology; Department of Laboratory Medicine; Karolinska Institute at Karolinska University Hospital Huddinge; Stockholm, Sweden
| | | | - Imre Kacskovics
- ImmunoGenes Kft; Budakeszi, Hungary; Department of Immunology; Eötvös Loránd University; Budapest, Hungary
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An intron mutation in the ACVRL1 may be associated with a transcriptional regulation defect in a Chinese family with hereditary hemorrhagic telangiectasia. PLoS One 2013; 8:e58031. [PMID: 23460919 PMCID: PMC3584037 DOI: 10.1371/journal.pone.0058031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Accepted: 01/30/2013] [Indexed: 11/27/2022] Open
Abstract
Purpose To identify a novel pathogenic gene mutation present in a Chinese family with hereditary hemorrhagic telangiectasia (HHT) and to determine if an intron mutation may influence the transcriptional activity of the ACVRL1 gene. Methods HHT family members were ascertained following the presentation of proband and involved subjects. All family members (n = 5) and 113 healthy individuals were genotyped for the variant in intron 6 c.772+27G>C of ACVRL1 gene. The genomic structure of ACVRL1 in affected HHT patients and healthy individuals was determined by long range PCR and sequencing. The expression of ACVRL1 mRNA and protein in patients with HHT was evaluated using real-time polymerase chain reaction and immunoblot analysis. Luciferase activity assay and electrophoretic mobility shift assay (EMSA) were performed to uncover the mechanism of intron-related transcriptional regulation. Results Only one novel mutation in intron 6 (c.772+27G>C) of ACVRL1 gene, no other mutation, abnormal splice, gross genomic deletion or rearrangement was found in this HHT2 family. Compared with healthy individuals, ACVRL1 mRNA and protein were significantly decreased in affected HHT2 individuals. Luciferase activity assay demonstrated that the transcriptional activity of the mutated ACVRL1 was significantly lower than that of the wild-type of intron 6; EMSA results showed that intron 6 c.772+27G>C mutation was able to inhibit the binding of transcriptional factor Sp1. Conclusions A novel intron mutation in ACVRL1 gene is associated with familial HHT2. The mechanisms may be involved in the down-regulation of ACVRL1 gene transcription.
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Ward ES, Ober RJ. Chapter 4: Multitasking by exploitation of intracellular transport functions the many faces of FcRn. Adv Immunol 2009; 103:77-115. [PMID: 19755184 DOI: 10.1016/s0065-2776(09)03004-1] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The MHC Class I-related receptor, FcRn, transports antibodies of the immunoglobulin G (IgG) class within and across a diverse array of different cell types. Through this transport, FcRn serves multiple roles throughout adult life that extend well beyond its earlier defined function of transcytosing IgGs from mother to offspring. These roles include the maintenance of IgG levels and the delivery of antigen in the form of immune complexes to degradative compartments within cells. Recent studies have led to significant advances in knowledge of the intracellular trafficking of FcRn and (engineered) IgGs at both the molecular and cellular levels. The engineering of FcRn-IgG (or Fc) interactions to generate antibodies of increased longevity represents an area of active interest, particularly in the light of the expanding use of antibodies in therapy. The strict pH dependence of FcRn-IgG interactions, with binding at pH 6 that becomes essentially undetectable as near neutral pH is approached, is essential for efficient transport. The requirement for retention of low affinity at near neutral pH increases the complexity of engineering antibodies for increased half-life. Conversely, engineered IgGs that have gained significant binding for FcRn at this pH can be potent inhibitors of FcRn that lower endogenous IgG levels and have multiple potential uses as therapeutics. In addition, molecular studies of FcRn-IgG interactions indicate that mice have limitations as preclinical models for FcRn function, primarily due to cross-species differences in FcRn-binding specificity.
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Affiliation(s)
- E Sally Ward
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Liu X, Ye L, Christianson GJ, Yang JQ, Roopenian DC, Zhu X. NF-kappaB signaling regulates functional expression of the MHC class I-related neonatal Fc receptor for IgG via intronic binding sequences. THE JOURNAL OF IMMUNOLOGY 2007; 179:2999-3011. [PMID: 17709515 PMCID: PMC2667116 DOI: 10.4049/jimmunol.179.5.2999] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The neonatal Fc receptor for IgG (FcRn) functions to transport maternal IgG to a fetus or newborn and to protect IgG from degradation. Although FcRn is expressed in a variety of tissues and cell types, the extent to which FcRn expression is regulated by immunological and inflammatory events remains unknown. Stimulation of intestinal epithelial cell lines, macrophage-like THP-1, and freshly isolated human monocytes with the cytokine TNF-alpha rapidly up-regulated FcRn gene expression. In addition, the TLR ligands LPS and CpG oligodeoxynucleotide enhanced the level of FcRn expression in THP-1 and monocytes. Treatment of TNF-stimulated THP-1 cells with the NF-kappaB-specific inhibitor or overexpression of a dominant negative mutant inhibitory NF-kappaB (IkappaBalpha; S32A/S36A) resulted in down-regulation of FcRn expression. By using chromatin immunoprecipitation we identified three NF-kappaB binding sequences within introns 2 and 4 of the human FcRn gene. An EMSA confirmed the p50/p50 and/or p65/p50 complex (s) bound to intron 2- or 4-derived oligonucleotides containing putative NF-kappaB binding sequences, respectively. The intronic NF-kappaB sequences in combination with the promoter or alone regulated the expression of a luciferase reporter gene in response to TNF-alpha stimulation or overexpression of NF-kappaB p65 and p50. DNA looping interactions potentially occurred after the stimulation between intronic NF-kappaB sequences and the FcRn promoter as shown by a chromosome conformation capture assay. Finally, TNF-alpha stimulations enhanced IgG transport across an intestinal Caco-2 epithelial monolayer. Together, these data provide the first evidence that NF-kappaB signaling via intronic sequences regulates FcRn expression and function.
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Affiliation(s)
- Xindong Liu
- Laboratory of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742
| | - Lilin Ye
- Laboratory of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742
| | | | - Jun-Qi Yang
- Department of Genome Science, University of Cincinnati College of Medicine, Cincinnati, OH 45237
| | | | - Xiaoping Zhu
- Laboratory of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742
- Address correspondence and reprint requests to Dr. Xiaoping Zhu, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, 8075 Greenmead Drive, College Park, MD 20742. E-mail address:
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Qiao SW, Lencer WI, Blumberg RS. How the controller is controlled - neonatal Fc receptor expression and immunoglobulin G homeostasis. Immunology 2006; 120:145-7. [PMID: 17140402 PMCID: PMC2265855 DOI: 10.1111/j.1365-2567.2006.02507.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Shuo-Wang Qiao
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Doleschall M, Zhao Y, Mayer B, Hammarström L, Kacskovics I. Isolation of the gene encoding the bovine neonatal Fc receptor. Vet Immunol Immunopathol 2005; 108:145-50. [PMID: 16095719 DOI: 10.1016/j.vetimm.2005.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The role of an IgG-Fc receptor (FcRn) that resembles a class I MHC Ag in transporting IgGs through epithelial cells was recently shown in selected species. Here we report our preliminary characterization of a clone encoding the alpha chain of the bovine FcRn from a BAC library. The recombinant BAC DNA was digested, analyzed by Southern blot hybridization and a bovine FcRn positive 9 kb long fragment was subcloned and partially sequenced. The exon/intron organization of the bovine FcRn alpha chain gene was deduced by comparison with its cDNA sequence. The sequence revealed a similar organization to the human and mouse FcRn alpha chain genes. The bovine FcRn alpha chain gene has acquired several repetitive sequences in its 5'-flanking region, including multiple SINE and LINE elements. Potential binding sites for transcription factors within the 5'-flanking sequence were identified using TESS and TFSEARCH programs. The 5'-flanking region of the bFcRn alpha chain gene was analyzed for its ability to directly express the luciferase reporter gene in bovine mammary gland epithelial cells. Transient transfection of a luciferase construct revealed that there was promoter activity in the region -1787 to +92 of the 5'-flanking sequence.
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Affiliation(s)
- Márton Doleschall
- Department of Physiology and Biochemistry, Faculty of Veterinary Science, Szent Istvan University, P.O. Box 2, H-1400 Budapest, Hungary
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