CD14 and complement crosstalk and largely mediate the transcriptional response to Escherichia coli in human whole blood as revealed by DNA microarray
ABSTRACT: Systemic inflammation like in sepsis is still lacking specific diagnostic markers and effective therapeutics. The first line of defense against intruding pathogens and endogenous damage signals is pattern recognition by e.g., complement and Toll-like receptors (TLR). Combined inhibition of a key complement component (C3 and C5) and TLR-co-receptor CD14 has been shown to attenuate certain systemic inflammatory responses. Using DNA microarray and gene annotation analyses, we aimed to decipher the effect of combined inhibition of C3 and CD14 on the transcriptional response to bacterial challenge in human whole blood. Importantly, combined inhibition reversed the transcriptional changes of 70% of the 2335 genes which significantly responded to heat-inactivated Escherichia coli by on average 80%. Single inhibition was less efficient (p<0.001) but revealed a suppressive effect of C3 on 21% of the responding genes which was partially counteracted by CD14. Furthermore, CD14 dependency of the Escherichia coli-induced response was increased in C5-deficient compared to C5-sufficient blood. The observed crucial distinct and synergistic roles for complement and CD14 on the transcriptional level correspond to their broad impact on the inflammatory response in human blood, and their combined inhibition may become inevitable in the early treatment of acute systemic inflammation. A microarray study was performed on whole blood from two healthy donors, a C5-deficient patient (C5D) (with and without C5-reconstitution) incubated for 120 min at 37oC with (i) PBS, (ii) E. coli or (iii) E. coli and inhibitors of complement (C3 or C5aR) and/or CD14 or inhibitor controls. The experiments were performed as biological replicates on two different days (healthy donor and C5D). Due to lack of a second C5-deficient patient, microarray analyses were prerformed twice (technical replicate) for C5D and day 1. Expression data in presence of PBS were used as reference for those in pressence of E. coli. Expression data in presence of E. coli were used as reference for those in pressence of E. coli and inhibitors. Expression data from 0 min incubation with PBS represent the initial state (T0). Whole blood was lysed in Applied Biosystems AB6100 total RNA chemistry lysis buffer and stored at -80oC prior to RNA extraction.
Project description:This study aims to investigate the effects of anti-complement component 5 antibody targeting MG4 domain on normal retina. Overall design: Mice were treated with intravitreal injection of anti-C5 antibody (1 or 10 μg/1 μL PBS). At 7 days after the injection, retinas were prepared from the enucleated eyes. Four retinas from 4 mice were put into a microcentrifuge tube for further analyses. 'Control', 'Therapeutic' and 'Toxic' groups mean that the mice received intravitreal PBS, 1 μg of anti-C5 antibody and 10 μg of anti-C5 antibody. Three biological replicates were included for each group.
Project description:Replication-deficient adenovirus (Ad) type 5 capsids induce potent host innate immune responses. One system pivotal in host innate immune defense is the complement system. Intriguingly, excessive or inappropriate complement activation can result in extreme tissue damage and systemic inflammatory responses similar to those noted immediately after high dose systemic Ad vector injections. To determine if the complement system has a significant role in intensifying Ad-associated acute toxicities, we compared complement deficient (C3-knockout (KO)) mice responses to those of wild type (WT) mice following systemic challenge with Ad vectors. We noted not only thrombocytopenia and rapid increases in plasma IL-6, IFN-γ, TNF-α, and IL-12 levels previously reported after high dose Ad injections into WT mice, but also induction of cytokines IL-2, IL-4, IL-5 and IL-10, G-CSF and GM-CSF, and chemokines KC (CXCL1) and MIP-1. This expanded innate response “profile” was significantly blunted in Ad injected C3-KO mice, with a near complete avoidance of thrombocytopenia. Further validation for complement’s critical role in perturbing these innate responses against Ad were noted after comparison of gene specific RNA transcription levels in C3-KO to WT mice livers. Finally, these disparities were not attributed to a diminished ability of the Ad vectors to transduce C3-KO mice hepatocytes. These results suggest that Ad capsid interaction with the mammalian complement system may exacerbate the toxicity of systemic Ad injections, and thus represents a future target for manipulation in efforts to improve the efficacy and safety profile of Ad mediated gene delivery. Keywords: adenovirus, complement system, time course, innate immune response, toxicity Overall design: C57/Bl6 (Wild-type or C3 Knock Outs) were injected with a high dose of a 1st generation LacZ adenovirus (1.5x10E11 particles per mouse) or mock nijected with 200ul of PBS. Virally transduced liver cell transcriptomes were compared to mick injected mice to determine viral gene network induction or repression in vivo.
Project description:Model of the Complement System
This is the continuous deterministic (ODE) model of the complement system described in the article:
Computational and Experimental Study of the Regulatory Mechanisms of the Complement System.
Liu B, Zhang J, Tan PY, Hsu D, Blom AM, Leong B, Sethi S, Ho B, Ding JL and Thiagarajan PS. PLoS Comp. Bio. 2011 Jan. 7:1; doi:10.1371/journal.pcbi.1001059
The complement system is key to innate immunity and its activation is necessary for the clearance of bacteria and apoptotic cells. However, insufficient or excessive complement activation will lead to immune-related diseases. It is so far unknown how the complement activity is up- or down- regulated and what the associated pathophysiological mechanisms are. To quantitatively understand the modulatory mechanisms of the complement system, we built a computational model involving the enhancement and suppression mechanisms that regulate complement activity. Our model consists of a large system of Ordinary Differential Equations (ODEs) accompanied by a dynamic Bayesian network as a probabilistic approximation of the ODE dynamics. Applying Bayesian inference techniques, this approximation was used to perform parameter estimation and sensitivity analysis. Our combined computational and experimental study showed that the antimicrobial response is sensitive to changes in pH and calcium levels, which determines the strength of the crosstalk between CRP and L-ficolin. Our study also revealed differential regulatory effects of C4BP. While C4BP delays but does not decrease the classical complement activation, it attenuates but does not significantly delay the lectin pathway activation. We also found that the major inhibitory role of C4BP is to facilitate the decay of C3 convertase. In summary, the present work elucidates the regulatory mechanisms of the complement system and demonstrates how the bio-pathway machinery maintains the balance between activation and inhibition. The insights we have gained could contribute to the development of therapies targeting the complement system.
Reproduction of figures in the article:
Figure 5: the effects of C4BP
Fig 5A: set initial concentrations PC=0.0327796, GlcNac=0, vary the initial concentration of C4BP from 2.6 to 2600 using parameter scan
Fig 5B: set initial concentrations PC=0, GlcNac=0.0327796, vary the initial concentration of C4BP from 2.6 to 2600 using parameter scan
Figure 6: knockout simulations
Set PC=0.0327796, GlcNac=0
Fig 6A: kf01=0, kf02=0
Fig 6B: kf04=0, kf06=0, kf07=0
Fig 6C: kf05=0
Fig 6D: kf03=0
This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2011 The BioModels.net Team.
To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.
Project description:The goals of this study are to investigate the function of Dpl2 of Tetrahymena thermophila. Overall design: Compare the expression of genes amnong WT and dpl∆ cells in C3, C4, C5, C6 and C7.
Project description:The goals of this study is to investigate the function of E2fl-1 of Tetrahymena thermophila. Overall design: Compare the expression of genes amnong WT and e2fl-1∆ cells in C2, C3, C4, C5, C6 and C7.
Project description:Transcriptional profiling of human lymphoblastoid cell lines with different ATM genotypes at basal level was compared to extract gene expression signatures that can identify ataxia telangiectasia (AT) carries from non AT carries and AT patients. Biological replicates: 4; Technical replicates: 2 with C3 and C5 dye swap.
Project description:Transcriptional profiling of human lymphoblastoid cell lines with different ATM genotypes 6h post sham- or 1.5 Gy IR-treatmentl was compared to extract IR-related gene expression signatures that can identify ataxia telangiectasia (AT) carries from non AT carries and AT patients. Biological replicates: 6 or 4; Technical replicates: 2 with C3 and C5 dye swap.
Project description:In this dataset, we include the expression data obtained from gastric cancer tissues and gastric normal tissues to determine the differentially expressed genes in gastric cancer tissues 10 tissues (5 paired of gastric cancer vs.normal tissues) were analysed. We generated the following pairwise comparisons:C1 VS.N1;C2 VS.N2;C3 VS.N3;C4 VS.N4;C5 VS.N5; genes with a fold-change ≥2 were selected
Project description:Age-related macular degeneration (AMD) is a common, blinding disease of the elderly in which macular photoreceptor cells, retinal pigment epithelium, and choriocapillaris endothelial cells ultimately degenerate. Recent studies have found that degeneration of the choriocapillaris occurs early in this disease and that this endothelial cell dropout is concomitant with increased deposition of the complement membrane attack complex (MAC) at the choroidal endothelium. However, the impact of MAC injury to choroidal endothelial cells is poorly understood. To model this event in vitro, and to study the downstream consequences of MAC injury, endothelial cells were exposed to complement from human serum, compared to heat inactivated serum which lacks complement components. Cells exposed to complement components in human serum showed increased labeling with antibodies directed against the MAC, time and dose dependent cell death as assessed by lactate dehydrogenase assay, and increased permeability. RNA-Seq analysis following complement injury revealed increased expression of genes associated with angiogenesis including matrix metalloproteases (MMPs) 3 and 9, and VEGF-A. The MAC-induced increase in MMP9 RNA expression was validated using C5 depleted serum compared to C5 reconstitited serum. Increased levels of MMP9 were also determined using Western blot and zymography. These data suggest that, in addition to cell lysis, complement attack on choroidal endothelial cells promotes an angiogenic phenotype in surviving cells. RNA-Seq of RF/6A (cultured choroidal endothelial cells from Rhesus macaque) treated with either 50% heat-inactivated human serum ([CONTROL], n=3) or 50% normal human serum (active complement membrane attack complex [MAC], n=3)