Title
A Computational And Experimental Study Of The Regulatory Mechanisms Of The Complement System
Abstract
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.
Year
DOI
Venue
2011
10.1371/journal.pcbi.1001059
PLOS COMPUTATIONAL BIOLOGY
Keywords
Field
DocType
ordinary differential equation,complement activation,dynamic bayesian network,bayesian inference,computer model,innate immunity,parameter estimation,sensitivity analysis
Biology,Complement system,Crosstalk,C3-convertase,Innate immune system,Bioinformatics,Inflammation,Lectin pathway,Immunoprecipitation,Bayes' theorem
Journal
Volume
Issue
ISSN
7
1
1553-734X
Citations 
PageRank 
References 
7
0.57
7
Authors
10
Name
Order
Citations
PageRank
Bing Liu114486811.80
Jing Zhang281.95
Pei Yi Tan370.57
David Hsu482450.86
Anna M. Blom570.91
Benjamin Leong680.96
Sunil Sethi770.57
Bow Ho870.57
Jeak Ling Ding970.57
P. S. Thiagarajan101497193.71