In vitro micro-physiological immune-competent model of the human skin

Abstract

Skin allergy, in particular, allergic contact dermatitis and irritant contact dermatitis, are common occupational and environmental health problems affecting the quality of life of a significant proportion of the world population. Since all new ingredients to be incorporated into a product are potential skin allergens, it is essential that these ingredients be first tested for their allergenic potential. However, despite the considerable effort using animal models to understand the underlying mechanism of skin sensitization, to date, the molecular and cellular responses due to skin contact with sensitizers are still not fully understood. To replace animal testing and to improve the prediction of skin sensitization, significant attention has been directed to the use of reconstructed organotypic in vitro models of human skin. Here we describe a miniaturized immune competent in vitro model of human skin based on 3D co-culture of immortalized human keratinocytes (HaCaT) as a model of the epidermis barrier and human leukemic monocyte lymphoma cell line (U937) as a model of human dendritic cells. The biological model was fitted in a microfluidic-based cell culture system that provides a dynamic cellular environment that mimics the in vivo environment of skin. The dynamic perfusion of culture media significantly improved the tight junction formation as evidenced by measuring higher values of TEER compared to static culture. This setting also maintained the high viability of cells over extended periods of time up to 17 days. The perfusion-based culture also allows growth of the cells at the air-liquid interface by exposing the apical side of the cells to air while providing the cell nutrients through a basolateral fluidic compartment. The microsystem has been evaluated to investigate the effect of the chemical and physical (UV irradiation) stimulation on the skin barrier (i.e. the TJ integrity). Three-tiered culture differential stimulation allowed the investigation of the role of the keratinocyte layer as a protection barrier to chemical/biological hazards.

Skin-on-a-chip model simulating inflammation, edema and drug-based treatment

“…Recently, several groups have reported work on skin-on-a-chip systems192729, and most of such skin models have been established by co-culturing dermis, epidermis or immune cells with skin cells. To the best of our knowledge, this is the first study to show a vascularized skin model with inflammation and edema achieved by co-culturing endothelium with skin cells.…”

“…Furthermore, recent advances in microfluidic systems have enabled the modeling of the physiology of various organs. These so-called organ-on-a-chip systems, including skin-on-a-chip devices192728, have the potential to offer physiologically relevant disease modeling and drug evaluation. Despite the considerable effort that has been directed toward constructing an in vitro model of skin, especially for edema evaluation, challenges remain because there are no skin-on-a-chip devices fully consisting of epidermal, dermal and endothelial layers.…”

Proteomic profiling of HaCaT keratinocytes exposed to skin damaging detergents

“…В отличие от первичных культур кератиноцитов, полученных от различных доноров и отличающихся высокой вариабельностью характеристик, клетки линии HaCaT способны неограниченно делиться, что определяет возможность получения стандартизованного объекта исследований и целесообразность их использования в качестве клеточной модели кожи in vitro [1]. Эти клетки часто используются для исследования токсичности химических веществ в отношении кожи, включая прогнозирование потенциального коррозионного или раздражающего эффекта [2].…”

In vitro skin three-dimensional models and their applications

“…Also, human induced pluripotent stem cells provide a source to mimic healthy and diseased skin models as they can be differentiated into keratinocytes [70], fibroblasts [71], melanocytes [72] and endothelial cells [67]. Besides simplified models with dermis and epidermis, also more complex models with hair follicles and adipocytes [73], immune cells [74] and features resembling sweat gland pores [75] exist. In addition, skin-on-a-chip can be expanded to multiple organ chips to test drug metabolism.…”