The epidermis renewal and homeostasis is maintained by a multistage process including cell proliferation, differentiation, migration, apoptosis and desquamation. We present a computational model of the spatial-temporal dynamics of the epidermis  . The model consists of a population kinetics model of the central transition pathway of keratinocyte proliferation, differentiation and loss and an agent-based cell migration model that propagates cell movements and generates the stratified epidermis. The model visualizes the epidermal renewal by embedding stochastic events of population kinetics into the cell migration events. The model reproduces observed cell density distribution and the epidermal turnover time. We apply the model to study the onset  and phototherapy-induced remission of psoriasis. The model considers the psoriasis as a parallel homeostasis of normal and psoriatic keratinocytes originated from a shared stem cell niche environment and predicts two steady-state modes of the psoriasis: a disease mode and a quiescent mode. The bimodal psoriasis is established by the interaction between psoriatic stem cells and the immune system  . The prediction of a quiescent state potentially explains the efficacy of the multi-episode UVB irradiation therapy and reoccurrence of psoriasis .
 We present a computational model of the spatial-temporal dynamics of the epidermis homeostasis . The model consists of a population kinetics model of the central transition pathway of keratinocyte proliferation, differentiation and loss and an agent-based cell migration model that propagates cell movements and generates the stratified epidermis. The model recapitulates observed cell density distribution and the epidermal turnover time. We apply the model to study the onset , recurrence and phototherapy-induced remission of psoriasis. The model considers the psoriasis as a parallel homeostasis of normal and psoriatic keratinocytes originated from a shared stem-cell niche environment and predicts two steady-state modes of the psoriasis: a disease mode and a quiescent mode. The interconversion between the two modes is established by the interaction between psoriatic stem cells and the immune system and by the normal and psoriatic stem cells competing for niches . The prediction of a quiescent state potentially explains the efficacy of the multi-episode UVB irradiation therapy and recurrence of psoriasis plaques, which can further guide designs of therapeutics that target the immune system and/or the keratinocytes .
D
The epidermis renewal and homeostasis is maintained by a multistage process including cell proliferation, differentiation, migration, apoptosis and desquamation.
A
homeostasis
R
visualizes the epidermal renewal by embedding stochastic events of population kinetics into the cell migration events. The model reproduces
recapitulates
A
, recurrence
R
stem cell
stem-cell
R
bimodal psoriasis
interconversion between the two modes
A
and by the normal and psoriatic stem cells competing for niches
R
reoccurrence of psoriasis
recurrence of psoriasis plaques, which can further guide designs of therapeutics that target the immune system and/or the keratinocytes