scholarly journals Activation of the Complement System in Patients with Cancer Cachexia

Cancers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 5767
Author(s):  
Min Deng ◽  
Rianne D. W. Vaes ◽  
Annemarie A. J. H. M. van Bijnen ◽  
Steven W. M. Olde Damink ◽  
Sander S. Rensen
Keyword(s):  
Systemic Inflammation ◽  
Complement System ◽  
Complement Activation ◽  
Cancer Cachexia ◽  
Strongly Correlated ◽  
Metabolic Inflammation ◽  
Classical Complement Pathway ◽  
Patients With Cancer ◽  
Reactive Protein ◽  
The Complement System

Systemic inflammation is thought to underlie many of the metabolic manifestations of cachexia in cancer patients. The complement system is an important component of innate immunity that has been shown to contribute to metabolic inflammation. We hypothesized that systemic inflammation in patients with cancer cachexia was associated with complement activation. Systemic C3a levels were higher in cachectic patients with inflammation (n = 23, C-reactive protein (CRP) ≥ 10 mg/L) as compared to patients without inflammation (n = 26, CRP < 10 mg/L) or without cachexia (n = 13) (medians 102.4 (IQR 89.4–158.0) vs. 81.4 (IQR 47.9–124.0) vs. 61.6 (IQR 46.8–86.8) ng/mL, respectively, p = 0.0186). Accordingly, terminal complement complex (TCC) concentrations gradually increased in these patient groups (medians 2298 (IQR 2022–3058) vs. 1939 (IQR 1725–2311) vs. 1805 (IQR 1552–2569) mAU/mL, respectively, p = 0.0511). C3a and TCC concentrations were strongly correlated (rs = 0.468, p = 0.0005). Although concentrations of C1q and mannose-binding lectin did not differ between groups, C1q levels were correlated with both C3a and TCC concentrations (rs = 0.394, p = 0.0042 and rs = 0.300, p = 0.0188, respectively). In conclusion, systemic inflammation in patients with cancer cachexia is associated with the activation of key effector complement factors. The correlations between C1q and C3a/TCC suggest that the classical complement pathway could play a role in complement activation in patients with pancreatic cancer.

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.

Interaction with complement proteins and dendritic cells implicates LCCL domain-containing proteins (CCps) of malaria parasites in immunomodulation

2018 ◽  
Vol 475 (21) ◽  
pp. 3311-3314 ◽  
Author(s):  
Puran Singh Sijwali
Keyword(s):  
Dendritic Cells ◽  
Complement System ◽  
Protein Complexes ◽  
Immune Defense ◽  
Malaria Parasites ◽  
Classical Complement Pathway ◽  
Soluble Immune Complexes ◽  
Multimeric Protein ◽  
The Complement System

The evasion of host immune defense is critical for pathogens to invade, establish infection and perpetuate in the host. The complement system is one of the first lines of innate immune defense in humans that destroys pathogens in the blood circulation. Activation of the complement system through direct encounter with pathogens or some other agents leads to osmolysis of pathogens, clearance of soluble immune complexes and recruitment of lymphocytes at the site of activation. Although malaria parasites are not exposed to the complement system owing to their intracellular development for most part of their life cycle in the human host, the extracellular stages must face the complement system of human or mosquito or both. In a recent issue of the Biochemical Journal, Sharma et al. reported that Plasmodiumfalciparum LCCL domain-containing protein 1 (PfCCp1) inhibited activation of the classical complement pathway and down-regulated effector responses of dendritic cells, which implicate PfCCp1 and related proteins in immunomodulation of the host that likely benefits the parasite. PfCCp1 belongs to a multi-domain protein family that exists as multimeric protein complexes. It needs to be investigated whether PfCCp1 or its multimeric protein complexes have an immunomodulatory effect in vivo and on the mosquito complement system

scholarly journals Complement modulation in the retinal pigment epithelium rescues photoreceptor degeneration in a mouse model of Stargardt disease

2017 ◽  
Vol 114 (15) ◽  
pp. 3987-3992 ◽  
Author(s):  
Tamara L. Lenis ◽  
Shanta Sarfare ◽  
Zhichun Jiang ◽  
Marcia B. Lloyd ◽  
Dean Bok ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Retinal Pigment Epithelium ◽  
Complement System ◽  
Complement Activation ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Host Cells ◽  
Etiologic Factor ◽  
Photoreceptor Degeneration ◽  
The Complement System

Recessive Stargardt macular degeneration (STGD1) is caused by mutations in the gene for the ABCA4 transporter in photoreceptor outer segments. STGD1 patients and Abca4−/− (STGD1) mice exhibit buildup of bisretinoid-containing lipofuscin pigments in the retinal pigment epithelium (RPE), increased oxidative stress, augmented complement activation and slow degeneration of photoreceptors. A reduction in complement negative regulatory proteins (CRPs), possibly owing to bisretinoid accumulation, may be responsible for the increased complement activation seen on the RPE of STGD1 mice. CRPs prevent attack on host cells by the complement system, and complement receptor 1-like protein y (CRRY) is an important CRP in mice. Here we attempted to rescue the phenotype in STGD1 mice by increasing expression of CRRY in the RPE using a gene therapy approach. We injected recombinant adeno-associated virus containing the CRRY coding sequence (AAV-CRRY) into the subretinal space of 4-wk-old Abca4−/− mice. This resulted in sustained, several-fold increased expression of CRRY in the RPE, which significantly reduced the complement factors C3/C3b in the RPE. Unexpectedly, AAV-CRRY–treated STGD1 mice also showed reduced accumulation of bisretinoids compared with sham-injected STGD1 control mice. Furthermore, we observed slower photoreceptor degeneration and increased visual chromophore in 1-y-old AAV-CRRY–treated STGD1 mice. Rescue of the STGD1 phenotype by AAV-CRRY gene therapy suggests that complement attack on the RPE is an important etiologic factor in STGD1. Modulation of the complement system by locally increasing CRP expression using targeted gene therapy represents a potential treatment strategy for STGD1 and other retinopathies associated with complement dysregulation.

scholarly journals Pretreatment with atorvastatin ameliorates cobra venom factor-induced acute lung inflammation in mice

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jing Guo ◽  
Min Li ◽  
Yi Yang ◽  
Lin Zhang ◽  
Li-wei Zhang ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Inflammatory Response ◽  
Protein Content ◽  
Complement System ◽  
Complement Activation ◽  
Lung Inflammation ◽  
Acute Lung Inflammation ◽  
Tnf Α ◽  
The Complement System

Abstract Background The complement system plays a critical role as the pathogenic factor in the models of acute lung injury due to various causes. Cobra venom factor (CVF) is a commonly used complement research tool. The CVF can cause acute inflammation in the lung by producing complement activation components. Atorvastatin (ATR) is a 3-hydroxy-3-methylglutaryl coenzyme A inhibitor approved for control of plasma cholesterol levels. This inhibitor can reduce the acute pulmonary inflammatory response. However, the ability of ATR in treating acute lung inflammation caused by complement activation is still unknown. Therefore, we investigated the effect of ATR on lung inflammation in mice induced by activation of the complement alternative pathway in this study. Methods ATR (10 mg/kg/day via oral gavage) was administered for 7 days before tail vein injection of CVF (25 μg/kg). On the seventh day, all mice were sacrificed 1 h after injection. The lung lobe, bronchoalveolar lavage fluid (BALF), and blood samples were collected. The myeloperoxidase (MPO) activity of the lung homogenate, the leukocyte cell count, and the protein content of BALF were measured. The levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), P-selectin, and Intercellular cell adhesion molecule-1 (ICAM-1) in BALF and serum were determined by enzyme-linked immunosorbent assay. The pathological change of the lung tissue was observed by hematoxylin and eosin staining. The deposition of C5b-9 in the lung tissue was detected by immunohistochemistry. The phosphorylation of NF-κB p65 in the lung tissues was examined by immunohistochemistry and western blotting. Results The lung inflammation levels were determined by measuring the leukocyte cell numbers and protein content of BALF, the lung MPO activity, and expression and staining of the inflammatory mediators (IL-6 and TNF-α), and adhesion molecules (P-selectin and ICAM-1) for lung lesion. A significant reduction in the lung inflammation levels was observed after 7 days in ATR pre-treated mice with a CVF-induced lung disease. Deposition of C5b-9 was significantly alleviated by ATR pretreatment. Early intervention with ATR significantly reduced the development of acute lung inflammation on the basis of phosphorylation of NF-κB p65 in the lung. Conclusion These findings suggest the identification of ATR treatment for the lung inflammation induced by activating the complement system on the basis of its anti-inflammatory response. Together with the model replicating the complement activating characteristics of acute lung injury, the results may be translatable to the overactivated complement relevant diseases.

scholarly journals Complement Activation Contributes to Severe Acute Respiratory Syndrome Coronavirus Pathogenesis

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Lisa E. Gralinski ◽  
Timothy P. Sheahan ◽  
Thomas E. Morrison ◽  
Vineet D. Menachery ◽  
Kara Jensen ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Host Defense ◽  
Complement System ◽  
Complement Activation ◽  
Fungal Infections ◽  
Central Component ◽  
Lung Pathology ◽  
Inflammatory Monocytes ◽  
The Complement System

ABSTRACT Acute respiratory distress syndrome (ARDS) is immune-driven pathologies that are observed in severe cases of severe acute respiratory syndrome coronavirus (SARS-CoV) infection. SARS-CoV emerged in 2002 to 2003 and led to a global outbreak of SARS. As with the outcome of human infection, intranasal infection of C57BL/6J mice with mouse-adapted SARS-CoV results in high-titer virus replication within the lung, induction of inflammatory cytokines and chemokines, and immune cell infiltration within the lung. Using this model, we investigated the role of the complement system during SARS-CoV infection. We observed activation of the complement cascade in the lung as early as day 1 following SARS-CoV infection. To test whether this activation contributed to protective or pathologic outcomes, we utilized mice deficient in C3 (C3–/–), the central component of the complement system. Relative to C57BL/6J control mice, SARS-CoV-infected C3–/– mice exhibited significantly less weight loss and less respiratory dysfunction despite equivalent viral loads in the lung. Significantly fewer neutrophils and inflammatory monocytes were present in the lungs of C3–/– mice than in C56BL/6J controls, and subsequent studies revealed reduced lung pathology and lower cytokine and chemokine levels in both the lungs and the sera of C3–/– mice than in controls. These studies identify the complement system as an important host mediator of SARS-CoV-induced disease and suggest that complement activation regulates a systemic proinflammatory response to SARS-CoV infection. Furthermore, these data suggest that SARS-CoV-mediated disease is largely immune driven and that inhibiting complement signaling after SARS-CoV infection might function as an effective immune therapeutic. IMPORTANCE The complement system is a critical part of host defense to many bacterial, viral, and fungal infections. It works alongside pattern recognition receptors to stimulate host defense systems in advance of activation of the adaptive immune response. In this study, we directly test the role of complement in SARS-CoV pathogenesis using a mouse model and show that respiratory disease is significantly reduced in the absence of complement even though viral load is unchanged. Complement-deficient mice have reduced neutrophilia in their lungs and reduced systemic inflammation, consistent with the observation that SARS-CoV pathogenesis is an immune-driven disease. These data suggest that inhibition of complement signaling might be an effective treatment option following coronavirus infection.

Human Mesenchymal Stem Cells Elicit Complement Activation in Human Blood.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4580-4580
Author(s):  
Katarina Le Blanc ◽  
Guido Moll ◽  
Ida Rasmusson ◽  
Kristina Nilsson Ekdahl ◽  
Graciela Elgue ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Human Blood ◽  
Complement System ◽  
Complement Activation ◽  
Immune Modulation ◽  
Effector Cell ◽  
Conflicts Of Interest ◽  
Cell Functions ◽  
The Complement System

Abstract Abstract 4580 Infusion of third-party mesenchymal stem cells (MSCs) appears to be a promising therapy for steroid-refractory acute graft-versus-host disease (GvHD). Little is known about how MSCs interact with the innate immune system after clinical infusion. In this study, we show that exposure of MSCs to ABO-compatible human blood activates the complement system, which triggers complement-mediated effector cell functions, and correlates with the immunosuppressive properties of MSCs. We found deposition of the complement component 3 (C3) derived opsonins iC3b and C3dg on MSCs, and fluid-phase generation of the chemotactic anaphylatoxins C3a and C5a. These events triggered complement receptor 3 (CD11b/CD18)-mediated effector cell activation; but could be prevented by culturing MSCs in human ABserum or by blocking complement function. Our study demonstrates the important role of the complement system as a possible mediator of immune modulation in clinical applications using MSCs, and implies that complement activation may substantially affect the treatment efficiency. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Heme Interacts with C1q and Inhibits the Classical Complement Pathway

2011 ◽  
Vol 286 (18) ◽  
pp. 16459-16469 ◽  
Author(s):  
Lubka T. Roumenina ◽  
Maria Radanova ◽  
Boris P. Atanasov ◽  
Krastio T. Popov ◽  
Srinivas V. Kaveri ◽  
...  
Keyword(s):  
Tissue Damage ◽  
Negative Regulator ◽  
Complement Pathway ◽  
Classical Complement Pathway ◽  
Reactive Protein ◽  
Free Heme ◽  
Direct Binding ◽  
Mechanism Of Recognition ◽  
The Complement System ◽  
Classical Complement

C1q is the recognition subunit of the first component of the classical complement pathway. It participates in clearance of immune complexes and apoptotic cells as well as in defense against pathogens. Inappropriate activation of the complement contributes to cellular and tissue damage in different pathologies, urging the need for the development of therapeutic agents that are able to inhibit the complement system. In this study, we report heme as an inhibitor of C1q. Exposure of C1q to heme significantly reduced the activation of the classical complement pathway, mediated by C-reactive protein (CRP) and IgG. Interaction analyses revealed that heme reduces the binding of C1q to CRP and IgG. Furthermore, we demonstrated that the inhibition of C1q interactions results from a direct binding of heme to C1q. Formation of complex of heme with C1q caused changes in the mechanism of recognition of IgG and CRP. Taken together, our data suggest that heme is a natural negative regulator of the classical complement pathway at the level of C1q. Heme may play a role at sites of excessive tissue damage and hemolysis where large amounts of free heme are released.

scholarly journals Influence of Mannan and Glucan on Complement Activation and C3 Binding by Candida albicans

2009 ◽  
Vol 78 (3) ◽  
pp. 1250-1259 ◽  
Author(s):  
Gayle M. Boxx ◽  
Thomas R. Kozel ◽  
Casey T. Nishiya ◽  
Mason X. Zhang
Keyword(s):  
Candida Albicans ◽  
Complement System ◽  
Complement Activation ◽  
Alternative Pathway ◽  
Surface Expression ◽  
Human Neutrophils ◽  
Intact Cells ◽  
Independent Mechanism ◽  
The Complement System ◽  
Wall Components

ABSTRACT The complement system is important for host resistance to hematogenously disseminated candidiasis. However, modulation of complement activation by cell wall components of Candida albicans has not been characterized. Although intact yeast display mannan on the surface, glucan, typically located in the interior, becomes exposed during C. albicans infection. We show here the distinct effects of mannan and glucan on complement activation and opsonophagocytosis. Previous studies showed that intact cells are resistant to initiation of complement activation through the alternative pathway, and antimannan antibody reverses this resistance via an Fc-independent mechanism. The present study shows that this mannan-dependent resistance can be overcome by periodate-borohydride conversion of mannose polysaccharides to polyalcohols; cells treated with periodate-borohydride initiate the alternative pathway without the need for antibody. These observations identify an inhibitory role for intact mannan in complement activation. Next, removal of the surface-displayed mannan by acid treatment of periodate-borohydride cells exposes glucan. Glucan-displaying cells or purified β-glucan initiate the alternative pathway when incubated with the purified proteins of the alternative pathway alone, suggesting that C. albicans glucan is a natural activator of the alternative pathway. Finally, ingestion of mannan-displaying cells by human neutrophils requires anti-mannan antibody, whereas ingestion of glucan-displaying cells requires complement. These results demonstrate a contrasting requirement of natural antibody and complement for opsonophagocytosis of C. albicans cells displaying mannan or glucan. Thus, differential surface expression of mannan and glucan may influence recognition of C. albicans by the complement system.

scholarly journals Interaction Between the Complement System and Infectious Agents – A Potential Mechanistic Link to Neurodegeneration and Dementia

2021 ◽  
Vol 15 ◽  
Author(s):  
Noriko Shinjyo ◽  
Wataru Kagaya ◽  
Marcela Pekna
Keyword(s):  
Nervous System ◽  
Complement System ◽  
Complement Activation ◽  
Neural Plasticity ◽  
Measles Virus ◽  
System Development ◽  
Critical Role ◽  
Nervous System Development ◽  
Infectious Agents ◽  
The Complement System

As part of the innate immune system, complement plays a critical role in the elimination of pathogens and mobilization of cellular immune responses. In the central nervous system (CNS), many complement proteins are locally produced and regulate nervous system development and physiological processes such as neural plasticity. However, aberrant complement activation has been implicated in neurodegeneration, including Alzheimer’s disease. There is a growing list of pathogens that have been shown to interact with the complement system in the brain but the short- and long-term consequences of infection-induced complement activation for neuronal functioning are largely elusive. Available evidence suggests that the infection-induced complement activation could be protective or harmful, depending on the context. Here we summarize how various infectious agents, including bacteria (e.g., Streptococcus spp.), viruses (e.g., HIV and measles virus), fungi (e.g., Candida spp.), parasites (e.g., Toxoplasma gondii and Plasmodium spp.), and prion proteins activate and manipulate the complement system in the CNS. We also discuss the potential mechanisms by which the interaction between the infectious agents and the complement system can play a role in neurodegeneration and dementia.

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