Boribong, Brittany P

Ciupe, Stanca

Jonea, Caroline N

Kadelka, Mirjam Sarah

Lenzi, Mark J

Li, Liwu

English

VCU Scholars Compass

Virginia Commonwealth UniversityVCU Scholars CompassBiology and Medicine Through MathematicsConference 2018May 31st, 11:00 AM - 11:30 AMQuantifying effects of neutrophil memory onmigration patterns using microfluidic platforms andODE modeling of the mechanistic molecularpathwaysBrittany P. BoribongVirginia Polytechnic Institute and State University, boribong@vt.eduMark J. LenziVirginia Polytechnic Institute and State University, mlenzi@vt.eduMirjam Sarah KadelkaVirginia Polytechnic Institute and State University, skadelka@vt.eduSee next page for additional authorsFollow this and additional works at: https://scholarscompass.vcu.edu/bammPart of the Biomedical Engineering and Bioengineering Commons, Immunology and InfectiousDisease Commons, Medicine and Health Sciences Commons, and the Ordinary DifferentialEquations and Applied Dynamics CommonsThis Event is brought to you for free and open access by the Dept. of Mathematics and Applied Mathematics at VCU Scholars Compass. It has beenaccepted for inclusion in Biology and Medicine Through Mathematics Conference by an authorized administrator of VCU Scholars Compass. Formore information, please contact libcompass@vcu.edu.https://scholarscompass.vcu.edu/bamm/2018/thursday/6Presenter InformationBrittany P. Boribong, Mark J. Lenzi, Mirjam Sarah Kadelka, Stanca Ciupe, Liwu Li, and Caroline N. JoneaThis event is available at VCU Scholars Compass: https://scholarscompass.vcu.edu/bamm/2018/thursday/6Quantifying effects of neutrophil memory on migration patterns using microfluidic platforms andODE modeling of the mechanistic molecular pathwaysDuring sepsis, the current leading cause of death in hospitals, neutrophils migrate and accumulate in healthyorgans instead of migrating toward the infection. Previous work from us described a dysfunctional phenotype, in-cluding oscillatory and spontaneous migration, in neutrophils isolated from septic burn patients [1]. In this study,we present a microfluidic platform to measure neutrophil chemotaxis in an opposing chemoattractant gradient toquantify neutrophil decision-making, with single-cell resolution. We use two chemoattractants: a pro-resolution(fMLP) and pro-inflammatory (LTB4) chemoattractant to model how a neutrophil makes a decision to move to-ward a bacterial infection versus an inflammatory signal. Our hypothesis, is that pro-inflammatory programmingor training signals, such as lipopolysaccharide, have a central role in determining the final neutrophil phenotypeand in the development of sepsis. Furthermore, the concentration of the LPS exposure is critical in determiningthe impending neutrophil phenotype. Leukocyte memory in relation to primary low-levels of LPS may lead to adysfunctional immune response to a secondary bacterial infection. On the other hand, exposure to high-levels of LPSlead to insufficient and dysfunctional migration and neutrophils are unable to contain infection. Despite tremendousadvances in the understanding of signaling molecules and pathways acting inside neutrophils, our understanding ofthe directional decision-making process of neutrophils is limited, and consequently, our abilities to modulate theactivity of neutrophils restricted.In our microfluidic platform, opposing linear chemoattractant gradients are formed along migration channels,and neutrophils (HL-60s) in the central loading chamber must make the decision to migrate toward a preferredchemoattractant. Time-lapse images were taken every 2 min. and cell mazes were incorporated to measure directionalmigration and capture oscillatory behavior of the cells. To test the importance of leukocyte memory, we stimulatethe cells overnight with a pro-inflammatory mediator (Lipopolysaccharide (LPS)) at both high (100 ng/mL) and low(1ng/mL) doses to determine if LPS plays a role in neutrophil decision-making. We show that unstimulated cellsmigrate toward fMLP over LTB4 in a 2:1 ratio. Cells stimulated with high-dose LPS show migration in a similarratio, but with a higher total percentage of migrating cells. Surprisingly, cells stimulated with a low dose of LPSmigrate toward fMLP and LTB4 in a 1:1 ratio, showing an increase in migration toward LTB4, as well as highermigration. We see higher velocity toward LTB4 and lower velocity toward fMLP compared to unstimulated cells.This study suggests that low-dose LPS stimulation can alter the decision-making properties of the neutrophil tomigrate toward an inflammatory signal over a bacterial infection.To understand the molecular mechanism of this cell memory, we combined our wet-bench work with an ODE-based dynamical framework to model the interaction of the mutually inhibitory GRK2 and GRK5 proteins and itsrole in neutrophil decision-making. GRK2 and GRK5 were of interest due to importance as drug targets as well astheir interactions with the chemoattractant receptors and LPS. Our computational model results show a bimodalswitch between high and low levels of GRK2. We are currently using open microfluidics to extract neutrophilson-chip after migration, to measure receptor levels to determine the underlying molecular mechanism and determinebiologically accurate parameter values for our computational model. In the future, this platform can be used forearly diagnosis of sepsis or to test the effect of pro-resolving mediators on neutrophil function.Reference: [1] Jones CN, PLoS One, 2014, 9(12), e1145091

Quantifying effects of neutrophil memory on migration patterns using microfluidic platforms and ODE modeling of the mechanistic molecular pathways

https://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=1255&amp;context=bamm

Quantifying effects of neutrophil memory on migration patterns using microfluidic platforms and ODE modeling of the mechanistic molecular pathways

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