scholarly journals C3 Deficiency Leads to Increased Angiogenesis and Elevated Pro-Angiogenic Leukocyte Recruitment in Ischemic Muscle Tissue

2021 ◽  
Vol 22 (11) ◽  
pp. 5800
Author(s):  
Philipp Götz ◽  
Anna Braumandl ◽  
Matthias Kübler ◽  
Konda Kumaraswami ◽  
Hellen Ishikawa-Ankerhold ◽  
...  
Keyword(s):  
Muscle Tissue ◽  
Complement System ◽  
Neutrophil Extracellular Trap ◽  
Complement Factor ◽  
Artery Ligation ◽  
Complement Factor C3 ◽  
Gastrocnemius Muscles ◽  
The Impact ◽  
The Complement System ◽  
Ischemic Muscle

The complement system is a potent inflammatory trigger, activator, and chemoattractant for leukocytes, which play a crucial role in promoting angiogenesis. However, little information is available about the influence of the complement system on angiogenesis in ischemic muscle tissue. To address this topic and analyze the impact of the complement system on angiogenesis, we induced muscle ischemia in complement factor C3 deficient (C3−/−) and wildtype control mice by femoral artery ligation (FAL). At 24 h and 7 days after FAL, we isolated the ischemic gastrocnemius muscles and investigated them by means of (immuno-)histological analyses. C3−/− mice showed elevated ischemic damage 7 days after FAL, as evidenced by H&E staining. In addition, angiogenesis was increased in C3−/− mice, as demonstrated by increased capillary/muscle fiber ratio and increased proliferating endothelial cells (CD31+/BrdU+). Moreover, our results showed that the total number of leukocytes (CD45+) was increased in C3−/− mice, which was based on an increased number of neutrophils (MPO+), neutrophil extracellular trap formation (MPO+/CitH3+), and macrophages (CD68+) displaying a shift toward an anti-inflammatory and pro-angiogenic M2-like polarized phenotype (CD68+/MRC1+). In summary, we show that the deficiency of complement factor C3 increased neutrophil and M2-like polarized macrophage accumulation in ischemic muscle tissue, contributing to angiogenesis.

scholarly journals A novel approach to immunoapheresis of C3a/C3 and proteomic identification of associates

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8218
Author(s):  
Wolfgang Winnicki ◽  
Peter Pichler ◽  
Karl Mechtler ◽  
Richard Imre ◽  
Ines Steinmacher ◽  
...  
Keyword(s):  
Complement System ◽  
Proteomic Analysis ◽  
Methodological Approach ◽  
Central Component ◽  
Complement Factor ◽  
Immunoaffinity Column ◽  
Novel Approach ◽  
Human Disorders ◽  
Complement Factor C3 ◽  
The Complement System

Background Complement factor C3 represents the central component of the complement cascade and its activation split product C3a plays an important role in inflammation and disease. Many human disorders are linked to dysregulation of the complement system and alteration in interaction molecules. Therefore, various therapeutic approaches to act on the complement system have been initiated. Methods and Results Aiming to develop a tool to eliminate C3a/C3 from the circulation, in a first step a high affine murine monoclonal antibody (mAb) (3F7E2-mAb) was generated against complement factor C3 and selected for binding to the C3a region to serve as immunoaffinity reagent. Functional testing of the 3F7E2-mAb revealed an inhibition of Zymosan-induced cleavage of C3a from C3. Subsequently, a C3a/C3 specific 3F7E2-immunoaffinity column was developed and apheresis of C3a/C3 and associates was performed. Finally, a proteomic analysis was carried out for identification of apheresis products. C3a/C3 was liberated from the 3F7E2-column together with 278 proteins. C3a/C3 interaction specificity was validated by using a haptoglobin immunoaffinity column as control and biostatistic analysis revealed 39 true C3a/C3 interactants. Conclusion A novel and functionally active mAb was developed against complement factor C3a/C3 and used in a specific immunoaffinity column that allows apheresis of C3a/C3 and associates and their identification by proteomic analysis. This methodological approach of developing specific antibodies that can be used as immunoaffinity reagents to design immunoaffinity columns for elimination and further identification of associated proteins could open new avenues for the development of tailored immunotherapy in various complement-mediated or autoimmune diseases.

scholarly journals Phosphorylation of complement factor C3 in vivo

1989 ◽  
Vol 261 (3) ◽  
pp. 1051-1054 ◽  
Author(s):  
S C Martin
Keyword(s):  
Complement System ◽  
Whole Blood ◽  
Complement Factor ◽  
S Protein ◽  
Atp Concentration ◽  
Central Protein ◽  
Complement Factor C3 ◽  
The Complement System

Complement factor C3, the central protein of the complement system, was found to be phosphorylated both in EDTA- and heparin-anticoagulated whole blood and in coagulating blood. Complement S protein (vitronectin) was also found to be phosphorylated under these conditions. Further, purified C3 was found to be a phosphoprotein in vivo, containing 0.15 mol of alkali-labile phosphate/mol of protein. The ATP concentration in plasma was measured and found to be about 2 microM.

scholarly journals Functional expression of complement factor I following AAV-mediated gene delivery in the retina of mice and human cells

Gene Therapy ◽  
2021 ◽  
Author(s):  
Anna K. Dreismann ◽  
Michelle E. McClements ◽  
Alun R. Barnard ◽  
Elise Orhan ◽  
Jane P. Hughes ◽  
...  
Keyword(s):  
Complement System ◽  
Functional Expression ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Complement Factor ◽  
Factor I ◽  
Complement Factor I ◽  
Age Related ◽  
The Complement System

AbstractDry age-related macular degeneration (AMD) is characterised by loss of central vision and currently has no approved medical treatment. Dysregulation of the complement system is thought to play an important role in disease pathology and supplementation of Complement Factor I (CFI), a key regulator of the complement system, has the potential to provide a treatment option for AMD. In this study, we demonstrate the generation of AAV constructs carrying the human CFI sequence and expression of CFI in cell lines and in the retina of C57BL/6 J mice. Four codon optimised constructs were compared to the most common human CFI sequence. All constructs expressed CFI protein; however, most codon optimised sequences resulted in significantly reduced CFI secretion compared to the non-optimised CFI sequence. In vivo expression analysis showed that CFI was predominantly expressed in the RPE and photoreceptors. Secreted protein in vitreous humour was demonstrated to be functionally active. The findings presented here have led to the formulation of an AAV-vectored gene therapy product currently being tested in a first-in-human clinical trial in subjects with geographic atrophy secondary to dry AMD (NCT03846193).

Aberrant activation of complement system in renal grafts is mediated by cold storage

2021 ◽  
Author(s):  
Sorena Lo ◽  
Li Jiang ◽  
Savannah Stacks ◽  
Haixia Lin ◽  
Nirmala Parajuli
Keyword(s):  
Cold Storage ◽  
Complement System ◽  
Complement Activation ◽  
Renal Tubules ◽  
Renal Transplants ◽  
Reducing Conditions ◽  
Tnf Α ◽  
Renal Grafts ◽  
The Impact ◽  
The Complement System

Aberrant complement activation leads to tissue damage during kidney transplantation, and it is recognized as an important target for therapeutic intervention (6, 19, 35, 64). However, it is not clear whether cold storage (CS) triggers the complement pathway in transplanted kidneys. The goal of this study was to determine the impact of CS on complement activation in renal transplants. Male Lewis and Fischer rats were used, and donor rat kidneys were exposed to 4 h or 18 h of CS followed by transplantation (CS+Transplant). To study CS-induced effects, a group with no CS was included in which the kidney was removed and transplanted back to the same rat (autotransplantation, ATx). Complement proteins (C3 and C5b-9) were evaluated with western blotting (reducing and non-reducing conditions) and immunostaining. Western blot of renal extracts or serum indicated that the levels of C3 and C5b-9 increased after CS+Transplant compared to ATx. Quite strikingly, intracellular C3 was profoundly elevated within renal tubules after CS+Transplant but was absent in Sham or ATx groups, which showed only extratubular C3. Similarly, C5b-9 immunofluorescence staining of renal sections showed an increase in C5b-9 deposits in kidneys after CS+Transplant. Real-time PCR (SYBR Green) showed increased expression of CD11b and CD11c, components of complement receptors 3 and 4, respectively, as well as inflammatory markers such as TNF-α. In addition, recombinant TNF-α significantly increased C3 levels in renal cells. Collectively, these results demonstrate that CS activates the complement system in renal transplants.

scholarly journals A Role for Complement in Feedback Enhancement of Antibody Responses by IgG3

2003 ◽  
Vol 197 (9) ◽  
pp. 1183-1190 ◽  
Author(s):  
Teresita Díaz de Ståhl ◽  
Jörgen Dahlström ◽  
Michael C. Carroll ◽  
Birgitta Heyman
Keyword(s):  
Feedback Regulation ◽  
Antibody Responses ◽  
Complement Factor ◽  
Complement Receptors ◽  
Wild Type ◽  
Gamma Chain ◽  
The Common ◽  
Feedback Enhancement ◽  
Complement Factor C3 ◽  
The Complement System

IgG1, IgG2a, and IgG2b, passively administered with soluble Ags, enhance specific Ab responses. The effect of IgG3 in this type of feedback regulation has not been studied previously. We immunized mice with trinitrophenyl (TNP)-coupled carrier proteins (bovine serum albumin [BSA] or ovalbumin [OVA]) alone or complexed to monoclonal TNP-specific IgG3. The carrier-specific Ab responses were enhanced by several hundred-fold by IgG3. Enhancement was significantly impaired in mice depleted of complement factor C3 and in mice lacking complement receptors 1 and 2 (Cr2−/−). In contrast, mice lacking the common Fc-receptor gamma chain (FcRγ−/−), resulting in reduced expression of FcγRI and lack of FcγRIII, and mice lacking FcγRIIB (FcγRIIB−/−), responded equally well to immunization with IgG3-complexed Ag as wild-type controls. These findings demonstrate that IgG3 can induce feedback enhancement and that IgG3, in analogy with IgM, uses the complement system for this function.

Reduced Mannose-Binding Lectin-Associated Serine Protease (MASP)-1 is Associated with Disturbed Coagulation in Septic Shock

2019 ◽  
Vol 119 (06) ◽  
pp. 952-961 ◽  
Author(s):  
Julie Brogaard Larsen ◽  
Mathies Appel Laursen ◽  
Christine Lodberg Hvas ◽  
Kim Michael Larsen ◽  
Steffen Thiel ◽  
...  
Keyword(s):  
Septic Shock ◽  
Complement System ◽  
Sofa Score ◽  
Thrombin Generation ◽  
Mannose Binding Lectin ◽  
Lectin Pathway ◽  
Complement Factor ◽  
Mannose Binding ◽  
The Complement System ◽  
Binding Lectin

Background Activation of the complement system is part of the dysregulated immune response in sepsis. The mannose-binding lectin-associated serine proteases (MASP)-1 and -2 activate the lectin pathway of the complement system. Besides, these proteins can activate coagulation in vitro. However, the role of the lectin pathway proteins in the development of sepsis-related disseminated intravascular coagulation (DIC) is only sparsely investigated. Aim This article investigates the association between lectin pathway proteins and coagulation disturbances in septic shock patients. Materials and Methods We included 36 septic shock patients from the intensive care unit, Aarhus University Hospital, Denmark. Blood samples were obtained within 24 hours after admission (day 1), and subsequently on day 2 and day 3. Plasma concentrations of mannose-binding lectin (MBL), H-ficolin, M-ficolin, CL-L1, CL-K1, MASP-1, -2 and -3, MBL-associated proteins of 19 and 44 kDa as well as complement factor C3dg were assessed. Standard coagulation parameters, thrombin generation, thrombin–anti-thrombin (TAT) complex and pro-thrombin fragment 1 + 2 were measured. Sequential Organ Failure Assessment (SOFA) score, DIC score and 30-day mortality were assessed. Results Reduced MASP-1 plasma concentration was associated with DIC score ≥5 (p = 0.02), impaired thrombin generation (p = 0.03) and lower plasma TAT complex levels (p = 0.03). No association was found between lectin pathway proteins and SOFA score or 30-day mortality. Conclusion Reduced MASP-1 concentrations were associated with impaired coagulation in septic shock patients. This indicates that increased MASP-1 activation and consumption is associated with the more severe coagulation disturbances in sepsis and points to a possible role for MASP-1 in sepsis-related DIC.

scholarly journals Role of the Classical Pathway of Complement Activation in Experimentally Induced Polymicrobial Peritonitis

2001 ◽  
Vol 69 (12) ◽  
pp. 7304-7309 ◽  
Author(s):  
Ilhan Celik ◽  
Cordula Stover ◽  
Marina Botto ◽  
Steffen Thiel ◽  
Sotiria Tzima ◽  
...  
Keyword(s):  
Complement System ◽  
Complement Activation ◽  
Immune Defense ◽  
Classical Pathway ◽  
Complement Factor ◽  
Wild Type ◽  
Factor B ◽  
The Complement System ◽  
Deficient Mice

ABSTRACT The complement system and the natural antibody repertoire provide a critical first-line defense against infection. The binding of natural antibodies to microbial surfaces opsonizes invading microorganisms and activates complement via the classical pathway. Both defense systems cooperate within the innate immune response. We studied the role of the complement system in the host defense against experimental polymicrobial peritonitis using mice lacking either C1q or factor B and C2. The C1q-deficient mice lacked the classical pathway of complement activation. The factor B- and C2-deficient mice were known to lack the classical and alternative pathways, and we demonstrate here that these mice also lacked the lectin pathway of complement activation. Using inoculum doses adjusted to cause 42% mortality in the wild-type strain, none of the mice deficient in the three activation routes of complement (factor B and C2 deficient) survived (mortality of 100%). Mortality in mice deficient only in the classical pathway of complement activation (C1q deficient) was 83%. Application of further dilutions of the polymicrobial inoculum showed a dose-dependent decrease of mortality in wild-type controls, whereas no changes in mortality were observed in the two gene-targeted strains. These results demonstrate that the classical activation pathway is required for an effective antimicrobial immune defense in polymicrobial peritonitis and that, in the infection model used, the remaining antibody-independent complement activation routes (alternative and lectin pathways) provide a supporting line of defense to gain residual protection in classical pathway deficiency.

scholarly journals Complement in Lupus Nephritis: New Perspectives

2015 ◽  
Vol 1 (2) ◽  
pp. 91-99 ◽  
Author(s):  
Lihua Bao ◽  
Patrick N. Cunningham ◽  
Richard J. Quigg
Keyword(s):  
Lupus Nephritis ◽  
Complement System ◽  
Complement Activation ◽  
Autoimmune Disorder ◽  
Factor H ◽  
Complement Factor ◽  
Dual Roles ◽  
Increased Risk ◽  
Wide Range ◽  
The Complement System

Background: Systemic lupus erythematosus (SLE) is an autoimmune disorder caused by loss of tolerance to self-antigens, the production of autoantibodies and deposition of complement-fixing immune complexes (ICs) in injured tissues. SLE is characterized by a wide range of clinical manifestations and targeted organs, with lupus nephritis being one of the most serious complications. The complement system consists of three pathways and is tightly controlled by a set of regulatory proteins to prevent injudicious complement activation on host tissue. The involvement of the complement system in the pathogenesis of SLE is well accepted; yet, its exact role is still not clear. Summary: Complement plays dual roles in the pathogenesis of SLE. On the one hand, the complement system appears to have protective features in that hereditary homozygous deficiencies of classical pathway components, such as C1q and C4, are associated with an increased risk for SLE. On the other hand, IC-mediated activation of complement in affected tissues is clearly evident in both experimental and human SLE along with pathological features that are logical consequences of complement activation. Studies in genetically altered mice have shown that lack of complement inhibitors, such as complement factor H (CFH) or decay-accelerating factor (DAF) accelerates the development of experimental lupus nephritis, while treatment with recombinant protein inhibitors, such as Crry-Ig, CR2-Crry, CR2-DAF and CR2-CFH, ameliorates the disease development. Complement-targeted drugs, including soluble complement receptor 1 (TP10), C1 esterase inhibitor and a monoclonal anti-C5 antibody (eculizumab), have been shown to inhibit complement safely, and are now being investigated in a variety of clinical conditions. Key Messages: SLE is an autoimmune disorder which targets multiple systems. Complement is centrally involved and plays dual roles in the pathogenesis of SLE. Studies from experimental lupus models and clinical trials support the use of complement-targeted therapy in the treatment of SLE.

scholarly journals The Impact of Graphite Oxide Nanocomposites on the Antibacterial Activity of Serum

2021 ◽  
Vol 22 (14) ◽  
pp. 7386
Author(s):  
Katarzyna Dorota Morka ◽  
Maciej Wernecki ◽  
Anna Kędziora ◽  
Marta Książczyk ◽  
Bartłomiej Dudek ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Human Serum ◽  
Complement System ◽  
Graphite Oxide ◽  
Galleria Mellonella ◽  
Serum Proteins ◽  
Normal Human Serum ◽  
Normal Human ◽  
The Impact ◽  
The Complement System

Nanoparticles can interact with the complement system and modulate the inflammatory response. The effect of these interactions on the complement activity strongly depends on physicochemical properties of nanoparticles. The interactions of silver nanoparticles with serum proteins (particularly with the complement system components) have the potential to significantly affect the antibacterial activity of serum, with serious implications for human health. The aim of the study was to assess the influence of graphite oxide (GO) nanocomposites (GO, GO-PcZr(Lys)2-Ag, GO-Ag, GO-PcZr(Lys)2) on the antibacterial activity of normal human serum (NHS), serum activity against bacteria isolated from alveoli treated with nanocomposites, and nanocomposite sensitivity of bacteria exposed to serum in vitro (using normal human serum). Additionally, the in vivo cytotoxic effect of the GO compounds was determined with application of a Galleria mellonella larvae model. GO-PcZr(Lys)2, without IR irradiation enhance the antimicrobial efficacy of the human serum. IR irradiation enhances bactericidal activity of serum in the case of the GO-PcZr(Lys)2-Ag sample. Bacteria exposed to nanocomposites become more sensitive to the action of serum. Bacteria exposed to serum become more sensitive to the GO-Ag sample. None of the tested GO nanocomposites displayed a cytotoxicity towards larvae.

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