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González-Alsina A, Martín-Merinero H, Mateu-Borrás M, Verd M, Doménech-Sánchez A, Goldberg JB, Rodríguez de Córdoba S, Albertí S. Role of factor H-related protein 3 in Pseudomonas aeruginosa bloodstream infections. Front Immunol 2024; 15:1449003. [PMID: 39295874 PMCID: PMC11408224 DOI: 10.3389/fimmu.2024.1449003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Accepted: 08/19/2024] [Indexed: 09/21/2024] Open
Abstract
Pseudomonas aeruginosa is a leading cause of nosocomial bloodstream infections. The outcome of these infections depends on the virulence of the microorganism as well as host-related conditions and factors. The complement system plays a crucial role in defense against bloodstream infections. P. aeruginosa counteracts complement attack by recruiting Factor H (FH) that inhibits complement amplification on the bacterial surface. Factor H-related proteins (FHRs) are a group of plasma proteins evolutionarily related to FH that have been postulated to interfere this bacterial evasion mechanism. In this study, we demonstrate that FHR-3 competes with purified FH for binding to P. aeruginosa and identify EF-Tu as a common bacterial target for both complement regulator factors. Importantly, elevated levels of FHR-3 in human serum promote complement activation, leading to increased opsonization and killing of P. aeruginosa. Conversely, physiological concentrations of FHR-3 have no significant effect. Our findings suggest that FHR-3 may serve as a protective host factor against P. aeruginosa infections.
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Affiliation(s)
- Alex González-Alsina
- Instituto Universitario de Investigación en Ciencias de la Salud (IUNICS), Universidad de las Islas Baleares and Instituto de Investigación Sanitaria de les Illes Balears (IDISBA), Palma de Mallorca, Spain
| | - Héctor Martín-Merinero
- Center for Biological Research-Margarita Salas and Centro de Investigación Biomédica En Red (CIBER) de Enfermedades Raras, Madrid, Spain
| | - Margalida Mateu-Borrás
- Instituto Universitario de Investigación en Ciencias de la Salud (IUNICS), Universidad de las Islas Baleares and Instituto de Investigación Sanitaria de les Illes Balears (IDISBA), Palma de Mallorca, Spain
| | - María Verd
- Instituto Universitario de Investigación en Ciencias de la Salud (IUNICS), Universidad de las Islas Baleares and Instituto de Investigación Sanitaria de les Illes Balears (IDISBA), Palma de Mallorca, Spain
| | - Antonio Doménech-Sánchez
- Instituto Universitario de Investigación en Ciencias de la Salud (IUNICS), Universidad de las Islas Baleares and Instituto de Investigación Sanitaria de les Illes Balears (IDISBA), Palma de Mallorca, Spain
| | - Joanna B Goldberg
- Department of Pediatrics, Emory-Children's Cystic Fibrosis Center, Division of Pulmonary, Asthma, Cystic Fibrosis, and Sleep, Emory University School of Medicine, Atlanta, GA, United States
| | - Santiago Rodríguez de Córdoba
- Center for Biological Research-Margarita Salas and Centro de Investigación Biomédica En Red (CIBER) de Enfermedades Raras, Madrid, Spain
| | - Sebastián Albertí
- Instituto Universitario de Investigación en Ciencias de la Salud (IUNICS), Universidad de las Islas Baleares and Instituto de Investigación Sanitaria de les Illes Balears (IDISBA), Palma de Mallorca, Spain
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Lee JH, Lee SH, Jeon C, Han J, Kim SH, Youn J, Park YS, Kim TJ, Kim JS, Jo S, Kim TH, Son CN. The complement factor H-related protein-5 (CFHR5) exacerbates pathological bone formation in ankylosing spondylitis. J Mol Med (Berl) 2024; 102:571-583. [PMID: 38418621 DOI: 10.1007/s00109-024-02428-6] [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: 08/18/2023] [Revised: 01/09/2024] [Accepted: 02/05/2024] [Indexed: 03/02/2024]
Abstract
Ankylosing spondylitis (AS) is a chronic inflammatory disease, characterized by excessive new bone formation. We previously reported that the complement factor H-related protein-5 (CFHR5), a member of the human factor H protein family, is significantly elevated in patients with AS compared to other rheumatic diseases. However, the pathophysiological mechanism underlying new bone formation by CFHR5 is not fully understood. In this study, we revealed that CFHR5 and proinflammatory cytokines (TNF, IL-6, IL-17A, and IL-23) were elevated in the AS group compared to the HC group. Correlation analysis revealed that CFHR5 levels were not significantly associated with proinflammatory cytokines, while CFHR5 levels in AS were only positively correlated with the high CRP group. Notably, treatment with soluble CFHR5 has no effect on clinical arthritis scores and thickness at hind paw in curdlan-injected SKG, but significantly increased the ectopic bone formation at the calcaneus and tibia bones of the ankle as revealed by micro-CT image and quantification. Basal CFHR5 expression was upregulated in AS-osteoprogenitors compared to control cells. Also, treatment with CFHR5 remarkedly induced bone mineralization status of AS-osteoprogenitors during osteogenic differentiation accompanied by MMP13 expression. We provide the first evidence demonstrating that CFHR5 can exacerbate the pathological bone formation of AS. Therapeutic modulation of CFHR5 could be promising for future treatment of AS. KEY MESSAGES: Serum level of CFHR5 is elevated and positively correlated with high CRP group of AS patients. Recombinant CFHR5 protein contributes to pathological bone formation in in vivo model of AS. CFHR5 is highly expressed in AS-osteoprogenitors compared to disease control. Recombinant CFHR5 protein increased bone mineralization accompanied by MMP13 in vitro model of AS.
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Affiliation(s)
- Ji-Hyun Lee
- Department of Rheumatology, Eulji Rheumatology Research Institute, Eulji University School of Medicine, 712 Dongil-Ro, Uijeongbu, Gyeonggi-Do, 11759, Republic of Korea
- Rheumarker Bio Inc, Daegu, Republic of Korea
| | - Seung Hoon Lee
- Hanyang University Institute for Rheumatology Research (HYIRR), 222-1 Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea
| | - Chanhyeok Jeon
- Hanyang University Institute for Rheumatology Research (HYIRR), 222-1 Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea
| | - Jinil Han
- Gencurix Inc, Seoul, Republic of Korea
| | - Sang-Hyon Kim
- Division of Rheumatology, Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Republic of Korea
| | - Jeehee Youn
- Department of Anatomy & Cell Biology, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - Ye-Soo Park
- Department of Orthopedic Surgery, Guri Hospital, Hanyang University College of Medicine, Guri, Gyeonggi-Do, Republic of Korea
| | - Tae-Jong Kim
- Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Jong-Seo Kim
- Center for RNA Research, Institute for Basic Science, Seoul, Republic of Korea
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sungsin Jo
- Hanyang University Institute for Rheumatology Research (HYIRR), 222-1 Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea.
- Department of Biology, College of Natural Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Asan, Chungcheongnam-do, 31358, Republic of Korea.
| | - Tae-Hwan Kim
- Hanyang University Institute for Rheumatology Research (HYIRR), 222-1 Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea.
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, 222-1 Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea.
| | - Chang-Nam Son
- Department of Rheumatology, Eulji Rheumatology Research Institute, Eulji University School of Medicine, 712 Dongil-Ro, Uijeongbu, Gyeonggi-Do, 11759, Republic of Korea.
- Rheumarker Bio Inc, Daegu, Republic of Korea.
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Tasaki Y, Tsujimoto H, Yokoyama T, Sugimoto N, Kitajima S, Fujii H, Hidaka Y, Kato N, Maruyama S, Inoue N, Wada T. Case report: A family of atypical hemolytic uremic syndrome involving a CFH::CFHR1 fusion gene and CFHR3-1-4-2 gene duplication. Front Immunol 2024; 15:1360855. [PMID: 38524137 PMCID: PMC10957550 DOI: 10.3389/fimmu.2024.1360855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 02/27/2024] [Indexed: 03/26/2024] Open
Abstract
Mutations in the complement factor H (CFH) gene are associated with complement dysregulation and the development of atypical hemolytic uremic syndrome (aHUS). Several fusion genes that result from genomic structural variation in the CFH and complement factor H-related (CFHR) gene regions have been identified in aHUS. However, one allele has both CFHR gene duplication and CFH::CFHR1 fusion gene have not been reported. An 8-month-old girl (proband) presented with aHUS and was treated with ravulizumab. Her paternal grandfather developed aHUS previously and her paternal great grandmother presented with anti-neutrophil cytoplasmic antibody-associated vasculitis and thrombotic microangiopathy (TMA). However, the proband's parents have no history of TMA. A genetic analysis revealed the presence of CFH::CFHR1 fusion gene and a CFHR3-1-4-2 gene duplication in the patient, her father, and her paternal grandfather. Although several fusion genes resulting from structural variations of the CFH-CFHR genes region have been identified, this is the first report of the combination of a CFH::CFHR1 fusion gene with CFHR gene duplication. Because the CFH-CFHR region is highly homologous, we hypothesized that CFHR gene duplication occurred. These findings indicate a novel pathogenic genomic structural variation associated with the development of aHUS.
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Affiliation(s)
- Yuko Tasaki
- Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical, and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Hiroshi Tsujimoto
- Department of Molecular Genetics, Wakayama Medical University, Wakayama, Japan
| | - Tadafumi Yokoyama
- Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical, and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Naotoshi Sugimoto
- Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical, and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Shinji Kitajima
- Department of Nephrology and Rheumatology, Kanazawa University, Kanazawa, Japan
| | - Hiroshi Fujii
- Department of Nephrology and Rheumatology, Ishikawa Prefectural Central Hospital, Kanazawa, Japan
| | - Yoshihiko Hidaka
- Department of Molecular Genetics, Wakayama Medical University, Wakayama, Japan
| | - Noritoshi Kato
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shoichi Maruyama
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Norimitsu Inoue
- Department of Molecular Genetics, Wakayama Medical University, Wakayama, Japan
| | - Taizo Wada
- Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical, and Health Sciences, Kanazawa University, Kanazawa, Japan
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Sándor N, Schneider AE, Matola AT, Barbai VH, Bencze D, Hammad HH, Papp A, Kövesdi D, Uzonyi B, Józsi M. The human factor H protein family - an update. Front Immunol 2024; 15:1135490. [PMID: 38410512 PMCID: PMC10894998 DOI: 10.3389/fimmu.2024.1135490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 01/08/2024] [Indexed: 02/28/2024] Open
Abstract
Complement is an ancient and complex network of the immune system and, as such, it plays vital physiological roles, but it is also involved in numerous pathological processes. The proper regulation of the complement system is important to allow its sufficient and targeted activity without deleterious side-effects. Factor H is a major complement regulator, and together with its splice variant factor H-like protein 1 and the five human factor H-related (FHR) proteins, they have been linked to various diseases. The role of factor H in inhibiting complement activation is well studied, but the function of the FHRs is less characterized. Current evidence supports the main role of the FHRs as enhancers of complement activation and opsonization, i.e., counter-balancing the inhibitory effect of factor H. FHRs emerge as soluble pattern recognition molecules and positive regulators of the complement system. In addition, factor H and some of the FHR proteins were shown to modulate the activity of immune cells, a non-canonical function outside the complement cascade. Recent efforts have intensified to study factor H and the FHRs and develop new tools for the distinction, quantification and functional characterization of members of this protein family. Here, we provide an update and overview on the versatile roles of factor H family proteins, what we know about their biological functions in healthy conditions and in diseases.
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Affiliation(s)
- Noémi Sándor
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
- HUN-REN-ELTE Complement Research Group, Hungarian Research Network, Budapest, Hungary
| | | | | | - Veronika H. Barbai
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Dániel Bencze
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Hani Hashim Hammad
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Alexandra Papp
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Dorottya Kövesdi
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
- HUN-REN-ELTE Complement Research Group, Hungarian Research Network, Budapest, Hungary
| | - Barbara Uzonyi
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
- HUN-REN-ELTE Complement Research Group, Hungarian Research Network, Budapest, Hungary
| | - Mihály Józsi
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
- HUN-REN-ELTE Complement Research Group, Hungarian Research Network, Budapest, Hungary
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5
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Cordero L, Cavero T, Gutiérrez E, Trujillo H, Sandino J, Auñón P, Rivero M, Morales E. Rational use of eculizumab in secondary atypical hemolytic uremic syndrome. Front Immunol 2024; 14:1310469. [PMID: 38274833 PMCID: PMC10808527 DOI: 10.3389/fimmu.2023.1310469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/20/2023] [Indexed: 01/27/2024] Open
Abstract
Background Secondary atypical hemolytic uremic syndrome (secondary aHUS) is a heterogeneous group of thrombotic microangiopathies (TMA) associated with various underlying conditions. Unlike primary aHUS, there is still no hard evidence on the efficacy of complement blockade in secondary aHUS, since the two main series that investigated this subject showed discrepant results. Our work aims to reassess the efficacy of eculizumab in treating secondary aHUS. Methods Observational, retrospective, single-center study, in which we analyzed the hematological and renal evolution of 23 patients diagnosed with secondary aHUS who received treatment with eculizumab and compared them with a control cohort of 14 patients. Complete renal response was defined as the recovery of renal function before the event, partial renal response as a recovery of 50% of lost glomerular filtration rate, and hematological response as normalization of hemoglobin and platelets. Results We found no statistically significant differences in baseline characteristics or disease severity between both groups. After a median of 5 doses of eculizumab, the group of patients who received complement blockade presented a significant difference in renal response (complete in 52.3% of patients and partial in 23.8%) compared to the control cohort (complete response 14.3% and partial of 14.3%). Rates of hematological remission were similar in both groups (90.9% in the eculizumab cohort and 85.7% in the control cohort). Conclusion Early and short-term use of eculizumab in patients with secondary aHUS could be an effective and safe therapeutic option, assuring better renal recovery compared to patients who do not receive complement blockade.
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Affiliation(s)
- Lucía Cordero
- Nephrology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Teresa Cavero
- Nephrology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Eduardo Gutiérrez
- Nephrology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Hernando Trujillo
- Nephrology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Justo Sandino
- Nephrology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Pilar Auñón
- Nephrology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Marta Rivero
- Nephrology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Enrique Morales
- Nephrology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
- Instituto de Investigación, Hospital Universitario 12 de Octubre (imas12), Madrid, Spain
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Rajasekaran A, Green TJ, Renfrow MB, Julian BA, Novak J, Rizk DV. Current Understanding of Complement Proteins as Therapeutic Targets for the Treatment of Immunoglobulin A Nephropathy. Drugs 2023; 83:1475-1499. [PMID: 37747686 PMCID: PMC10807511 DOI: 10.1007/s40265-023-01940-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2023] [Indexed: 09/26/2023]
Abstract
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide and a frequent cause of kidney failure. Currently, the diagnosis necessitates a kidney biopsy, with routine immunofluorescence microscopy revealing IgA as the dominant or co-dominant immunoglobulin in the glomerular immuno-deposits, often with IgG and sometimes IgM or both. Complement protein C3 is observed in most cases. IgAN leads to kidney failure in 20-40% of patients within 20 years of diagnosis and reduces average life expectancy by about 10 years. There is increasing clinical, biochemical, and genetic evidence that the complement system plays a paramount role in the pathogenesis of IgAN. The presence of C3 in the kidney immuno-deposits differentiates the diagnosis of IgAN from subclinical glomerular mesangial IgA deposition. Markers of complement activation via the lectin and alternative pathways in kidney-biopsy specimens are associated with disease activity and are predictive of poor outcome. Levels of select complement proteins in the circulation have also been assessed in patients with IgAN and found to be of prognostic value. Ongoing genetic studies have identified at least 30 loci associated with IgAN. Genes within some of these loci encode complement-system regulating proteins that can interact with immune complexes. The growing appreciation for the central role of complement components in IgAN pathogenesis highlighted these pathways as potential treatment targets and sparked great interest in pharmacological agents targeting the complement cascade for the treatment of IgAN, as evidenced by the plethora of ongoing clinical trials.
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Affiliation(s)
- Arun Rajasekaran
- Division of Nephrology, Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Todd J Green
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Matthew B Renfrow
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Bruce A Julian
- Division of Nephrology, Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jan Novak
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dana V Rizk
- Division of Nephrology, Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
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Zhao F, Bai Y, Xiang X, Pang X. The role of fibromodulin in inflammatory responses and diseases associated with inflammation. Front Immunol 2023; 14:1191787. [PMID: 37483637 PMCID: PMC10360182 DOI: 10.3389/fimmu.2023.1191787] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 06/23/2023] [Indexed: 07/25/2023] Open
Abstract
Inflammation is an immune response that the host organism eliminates threats from foreign objects or endogenous signals. It plays a key role in the progression, prognosis as well as therapy of diseases. Chronic inflammatory diseases have been regarded as the main cause of death worldwide at present, which greatly affect a vast number of individuals, producing economic and social burdens. Thus, developing drugs targeting inflammation has become necessary and attractive in the world. Currently, accumulating evidence suggests that small leucine-rich proteoglycans (SLRPs) exhibit essential roles in various inflammatory responses by acting as an anti-inflammatory or pro-inflammatory role in different scenarios of diseases. Of particular interest was a well-studied member, termed fibromodulin (FMOD), which has been largely explored in the role of inflammatory responses in inflammatory-related diseases. In this review, particular focus is given to the role of FMOD in inflammatory response including the relationship of FMOD with the complement system and immune cells, as well as the role of FMOD in the diseases associated with inflammation, such as skin wounding healing, osteoarthritis (OA), tendinopathy, atherosclerosis, and heart failure (HF). By conducting this review, we intend to gain insight into the role of FMOD in inflammation, which may open the way for the development of new anti-inflammation drugs in the scenarios of different inflammatory-related diseases.
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Affiliation(s)
- Feng Zhao
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Yang Bai
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Xuerong Xiang
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoxiao Pang
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital of Chongqing Medical University, Chongqing, China
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Ruiz-Molina N, Parsons J, Decker EL, Reski R. Structural modelling of human complement FHR1 and two of its synthetic derivatives provides insight into their in-vivo functions. Comput Struct Biotechnol J 2023; 21:1473-1486. [PMID: 36851916 PMCID: PMC9957715 DOI: 10.1016/j.csbj.2023.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/02/2023] [Accepted: 02/02/2023] [Indexed: 02/05/2023] Open
Abstract
Human complement is the first line of defence against invading pathogens and is involved in tissue homeostasis. Complement-targeted therapies to treat several diseases caused by a dysregulated complement are highly desirable. Despite huge efforts invested in their development, only very few are currently available, and a deeper understanding of the numerous interactions and complement regulation mechanisms is indispensable. Two important complement regulators are human Factor H (FH) and Factor H-related protein 1 (FHR1). MFHR1 and MFHR13, two promising therapeutic candidates based on these regulators, combine the dimerization and C5-regulatory domains of FHR1 with the central C3-regulatory and cell surface-recognition domains of FH. Here, we used AlphaFold2 to model the structure of these two synthetic regulators. Moreover, we used AlphaFold-Multimer (AFM) to study possible interactions of C3 fragments and membrane attack complex (MAC) components C5, C7 and C9 in complex with FHR1, MFHR1, MFHR13 as well as the best-known MAC regulators vitronectin (Vn), clusterin and CD59, whose experimental structures remain undetermined. AFM successfully predicted the binding interfaces of FHR1 and the synthetic regulators with C3 fragments and suggested binding to C3. The models revealed structural differences in binding to these ligands through different interfaces. Additionally, AFM predictions of Vn, clusterin or CD59 with C7 or C9 agreed with previously published experimental results. Because the role of FHR1 as MAC regulator has been controversial, we analysed possible interactions with C5, C7 and C9. AFM predicted interactions of FHR1 with proteins of the terminal complement complex (TCC) as indicated by experimental observations, and located the interfaces in FHR11-2 and FHR14-5. According to AFM prediction, FHR1 might partially block the C3b binding site in C5, inhibiting C5 activation, and block C5b-7 complex formation and C9 polymerization, with similar mechanisms of action as clusterin and vitronectin. Here, we generate hypotheses and give the basis for the design of rational approaches to understand the molecular mechanism of MAC inhibition, which will facilitate the development of further complement therapeutics.
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Affiliation(s)
- Natalia Ruiz-Molina
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Juliana Parsons
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Eva L Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
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9
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Biasella F, Plössl K, Baird PN, Weber BHF. The extracellular microenvironment in immune dysregulation and inflammation in retinal disorders. Front Immunol 2023; 14:1147037. [PMID: 36936905 PMCID: PMC10014728 DOI: 10.3389/fimmu.2023.1147037] [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: 01/18/2023] [Accepted: 02/15/2023] [Indexed: 03/05/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) as well as genetically complex retinal phenotypes represent a heterogenous group of ocular diseases, both on account of their phenotypic and genotypic characteristics. Therefore, overlaps in clinical features often complicate or even impede their correct clinical diagnosis. Deciphering the molecular basis of retinal diseases has not only aided in their disease classification but also helped in our understanding of how different molecular pathologies may share common pathomechanisms. In particular, these relate to dysregulation of two key processes that contribute to cellular integrity, namely extracellular matrix (ECM) homeostasis and inflammation. Pathological changes in the ECM of Bruch's membrane have been described in both monogenic IRDs, such as Sorsby fundus dystrophy (SFD) and Doyne honeycomb retinal dystrophy (DHRD), as well as in the genetically complex age-related macular degeneration (AMD) or diabetic retinopathy (DR). Additionally, complement system dysfunction and distorted immune regulation may also represent a common connection between some IRDs and complex retinal degenerations. Through highlighting such overlaps in molecular pathology, this review aims to illuminate how inflammatory processes and ECM homeostasis are linked in the healthy retina and how their interplay may be disturbed in aging as well as in disease.
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Affiliation(s)
- Fabiola Biasella
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Karolina Plössl
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Paul N. Baird
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
- Department of Surgery, Ophthalmology, University of Melbourne, Melbourne, VIC, Australia
- *Correspondence: Paul N. Baird, ; Bernhard H. F. Weber,
| | - Bernhard H. F. Weber
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
- Institute of Clinical Human Genetics, University Hospital Regensburg, Regensburg, Germany
- *Correspondence: Paul N. Baird, ; Bernhard H. F. Weber,
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10
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de Jong S, Tang J, Clark SJ. Age-related macular degeneration: A disease of extracellular complement amplification. Immunol Rev 2023; 313:279-297. [PMID: 36223117 DOI: 10.1111/imr.13145] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Age-related macular degeneration (AMD) is a major cause of vision impairment in the Western World, and with the aging world population, its incidence is increasing. As of today, for the majority of patients, no treatment exists. Multiple genetic and biochemical studies have shown a strong association with components in the complement system and AMD, and evidence suggests a major role of remodeling of the extracellular matrix underlying the outer blood/retinal barrier. As part of the innate immune system, the complement cascade acts as a first-line defense against pathogens, and upon activation, its amplification loop ensures a strong, rapid, and sustained response. Excessive activation, however, can lead to host tissue damage and cause complement-associated diseases like AMD. AMD patients present with aberrant activation of the alternative pathway, especially in ocular tissues but also on a systemic level. Here, we review the latest findings of complement activation in AMD, and we will discuss in vivo observations made in human tissue, cellular models, the potential synergy of different AMD-associated pathways, and conclude on current clinical trials and the future outlook.
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Affiliation(s)
- Sarah de Jong
- Department for Ophthalmology, University Eye Clinic, Eberhard Karls University of Tübingen, Tübingen, Germany.,Department for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Jiaqi Tang
- Department for Ophthalmology, University Eye Clinic, Eberhard Karls University of Tübingen, Tübingen, Germany.,Department for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Simon J Clark
- Department for Ophthalmology, University Eye Clinic, Eberhard Karls University of Tübingen, Tübingen, Germany.,Department for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University of Tübingen, Tübingen, Germany.,Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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