title: Observing single cell NF-κB dynamics under stimulant concentration gradient.
abstract: Study of cell signaling often requires examination of the cellular dynamics under variation in the stimulant concentration. Such variation has typically been conducted by dispensing cell populations in a number of chambers or wells containing discrete concentrations. Such practice adds to the complexity associated with experimental or device design and requires substantial labor for implementation. Furthermore, there is also potential risk of missing important results due to the often arbitrary selection of discrete concentration values for testing. In this Letter, we study NF-κB activation and translocation at the single cell level using a microfluidic device that generates continuously varying concentration gradient. We use only three device settings to cover stimulant (interleukin-1β) concentrations of 4 orders of magnitude (0.001-10 ng/mL). Such device allows us to study temporal dynamics of NF-κB in single cells under different stimulant concentrations by real-time imaging. Interestingly, our results reveal that, while the percent of cells with NF-κB translocation decreases with lower stimulant concentration in the range of 0.1-0.001 ng/mL, the response time of such translocation remains constant, reflected by the single cell data.
authors.affiliation: School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University, Blacksburg, Virginia 24061, USA.
authors.forename: Yousef
authors.initials: Y
authors.lastname: Awwad
authors.forename: Tao
authors.initials: T
authors.lastname: Geng
authors.forename: Albert S
authors.initials: AS
authors.lastname: Baldwin
authors.forename: Chang
authors.initials: C
authors.lastname: Lu
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D053583:Interleukin-1beta / Q000737:chemistry; D046210:Microfluidic Analytical Techniques; D008856:Microscopy, Fluorescence; D016328:NF-kappa B / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism
chemical_list: D053583:Interleukin-1beta; D016328:NF-kappa B; D011993:Recombinant Fusion Proteins; D051996:Transcription Factor RelA; D049452:Green Fluorescent Proteins