title: Hypoxic behavior in cells under controlled microfluidic environment.
abstract: Depleted oxygen levels, known as hypoxia, causes considerable changes in the cellular metabolism. Hypoxia-inducible factors (HIF) act as the major protagonist in orchestrating manifold hypoxic responses by escaping cellular degradation mechanisms. These complex and dynamic intracellular responses are significantly dependent on the extracellular environment. In this study, we present a detailed model of a hypoxic cellular microenvironment in a microfluidic setting involving HIF hydroxylation.
  
  
  
  We have modeled the induction of hypoxia in a microfluidic chip by an unsteady permeation of oxygen from the microchannel through a porous polydimethylsiloxane channel wall. Extracellular and intracellular interactions were modeled with two different mathematical descriptions. Intracellular space is directly coupled to the extracellular environment through uptake and consumption of oxygen and ascorbate similar to cells in vivo.
  
  
  
  Our results indicate a sharp switch in HIF hydroxylation behavior with changing prolyl hydroxylase levels from 0.1 to 4.0μM. Furthermore, we studied the effects of extracellular ascorbate concentration, using a new model, to predict its accumulation inside the cell over a relevant physiological range. In different hypoxic conditions, the cellular environment showed a significant dependence on oxygen levels in resulting intracellular response.
  
  
  
  Change in hydroxylation behavior and nutrient supplementation can have significant potential in designing novel therapeutic interventions in cancer and ischemia/reperfusion injuries.
  
  
  
  The hybrid mathematical model can effectively predict intracellular behavior due to external influences providing valuable directions in designing future experiments.
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, United States.
authors.forename: Adnan
authors.initials: A
authors.lastname: Morshed
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, United States. Electronic address: prashanta@wsu.edu.
authors.forename: Prashanta
authors.initials: P
authors.lastname: Dutta
mesh_terms: D015687:Cell Hypoxia / Q000502:physiology*; D060833:Cellular Microenvironment / Q000502:physiology*; D006801:Humans; D006900:Hydroxylation / Q000502:physiology; D051793:Hypoxia-Inducible Factor 1 / Q000378:metabolism; D044085:Microfluidics / Q000379:methods; D008954:Models, Biological; D008962:Models, Theoretical; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D010100:Oxygen / Q000378:metabolism; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology
chemical_list: D051793:Hypoxia-Inducible Factor 1; D010100:Oxygen
keywords: HIF; Hypoxic response; ascorbate; computational biology; microfluidics