簡介

在動態的環境里面，細胞們通過各遺傳途徑的相互作用交流運轉著。哺乳動物免疫反應就是各類不同的細胞協同合作的一個驚人例子。細胞與細胞之間的交流主要是通過信號分子形成時間與空間濃度梯度來介導的，這就要求細胞對一個大范圍內的信號強度產生響應。這篇文章采用高通量的微流體細胞培養(high-throughput microfluidic cell culture)和熒光顯微鏡，定量基因表達分析和建立數學模型等研究手段來評估到底單個哺乳動物細胞如何對不同濃度的信號分子TNF-α產生相應的響應。 并高度肯定了以單細胞級別進行高通量基因定量對研究生物系統如何運作的價值。

Letter

Nature 466, 267-271 (8 July 2010) | doi:10.1038/nature09145; Received 29 December 2009; Accepted 28 April 2010; Published online 27 June 2010
Single-cell NF-κB dynamics reveal digital activation and analogue information processing Savaş Tay1,2,4, Jacob J. Hughey1,4, Timothy K. Lee1, Tomasz Lipniacki3, Stephen R. Quake1,2 & Markus W. Covert1
1.  Department of Bioengineering, Stanford University, Stanford, California 94305, USA

2.  Howard Hughes Medical Institute, Stanford, California 94305, USA

3.  Institute of Fundamental Technological Research, Warsaw 02-106, Poland

4.  These authors contributed equally to this work.

Abstract

Cells operate in dynamic environments using extraordinary communication capabilities that emerge from the interactions of genetic circuitry. The mammalian immune response is a striking example of the coordination of different cell types1. Cell-to-cell communication is primarily mediated by signalling molecules that form spatiotemporal concentration gradients, requiring cells to respond to a wide range of signal intensities2. Here we use high-throughput microfluidic cell culture3 and fluorescence microscopy, quantitative gene expression analysis and mathematicalmodelling to investigate how single mammalian cells respond to different concentrations of the signaling molecule tumour-necrosis factor (TNF)-α, and relay information to the gene expression programs by means of the transcription factor nuclear factor (NF)-κB. We measured NF-κB activity in thousands of live cells under TNF-α doses covering four orders of magnitude. We find, in contrast to population-level studies with bulk assays2, that the activation is heterogeneous and is a digital process at the single-cell level with fewer cells responding at lower doses. Cells also encode a subtle set of analogue parameters to modulate the outcome; these parameters include NF-κB peak intensity, response time and number of oscillations. We developed a stochastic mathematical model that reproduces both the digital and analogue dynamics as well as most gene expression profiles at all measured conditions, constituting a broadly applicable model for TNF-α-induced NF-κB signalling in various types of cells. These results highlight the value of high-throughput quantitative measurements with single-cell resolution in understanding how biological systems operate.