title: Integration of pharmacokinetic and  intracellular models of interferon  administration and induced responses
creator: Kalra, Priyata
subject: ddc-570
subject: 570 Life sciences
description: A thorough understanding of drug-target relationships is essential in preclinical  and clinical translation studies. However, there is a gap of knowledge in the quantitative  understanding of dose-response relationships at the target site. To fill that  gap, a particularly promising approach is quantitative systems pharmacology (QSP)  where, mechanistic and hence comprehensive models of dose-effect relationships  are used to guide the design of clinical and translational studies.  In this thesis, I present for the first time a QSP approach for a therapeutic protein, interferon  alpha (IFN-a), by coupling physiologically based pharmacokinetic (PBPK)  models at the whole-body level with intracellular models of signal transduction in  the liver. Whole-body distribution models of an injected dose of IFN-a calibrated to  quantitative measurements of the plasma concentration are established for humans  and mice. They are then coupled to mechanistic intracellular models of the triggered  JAK/STAT signalling cascade that describes the dynamic response in the expression  of the antiviral mRNAc of IRF9 for humans and antiviral protein Mx2 for mice on  the cellular scale. By doing so, I am able to establish the quantitative dose-effect relationship  of the injected IFN-a dose to the responding interferon stimulated genes  (ISGs) triggered at the target site, the liver.  The established multi-scale physiologically based pharmacokinetic/pharmacodynamic  (PBPK/PD) model of human predict a reduced response of IRF9 mRNAc  to IFN-a under physiological in vivo conditions as compared to in vitro. The QSP  model also elicits the large impact of the IFN-receptors on the clearance of IFN-a in  the liver, thus, not only providing mechanistic insights into the pharmacodynamic  (PD) response but also elucidating the influence of receptor variability on the response.  Although IFN-a is specifically used in humans, in preclinical studies, it is also tested  in mice for understanding the medical impact of IFN-a for other diseases. Therefore,  I elaborate an analogous QSP model for the IFN-a response in mice to illustrate possibilities  of model-based cross species translation. Like the human model, a whole  body PBPK/PD mouse model was also established to follow the response of antiviral  protein Mx2. The model clarified the differences between the pharmacokinetics  of human and murine IFN-a injection in mice and will support quantitative crossspecies  extrapolation in the future.  Finally, as heterogeneity in ISGs reflects inter-cell variability in response to IFN-a, I  study the impact of sources of this heterogeneity by implementing the mechanistic  stochastic model of the JAK/STAT signalling pathway. The model was developed  on the basis of time-resolved flow cytometry data of two ISGs, MxA and IFIT1, in  Huh7.5 cells. The model analysed intrinsic variability in the concentration of the  molecules of the pathway and generated a graded response of MxA and IFIT1 instead  of an all-or-none response. Ultimately, the model concludes that the stochasticity  in the initiation of the signalling pathway, i.e., at the receptor level, can be  buffered by the system and a more robust response of ISGs, MxA and IFIT1 is induced.
date: 2019
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/27362/1/Priyata_Thesis_eversion.pdf
identifier: DOI:10.11588/heidok.00027362
identifier: urn:nbn:de:bsz:16-heidok-273623
identifier:   Kalra, Priyata  (2019) Integration of pharmacokinetic and intracellular models of interferon administration and induced responses.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/27362/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng