Air‐liquid interface cell culture: From airway epithelium to the female reproductive tract

Abstract

The air‐liquid interface (ALI) approach is primarily used to mimic respiratory tract epithelia in vitro. It is also known to support excellent differentiation of 3D multilayered skin models. To establish an ALI culture, epithelial cells are seeded into compartmentalized culture systems on porous filter supports or gel substrata. After an initial propagation period, the culture medium is removed from the apical side of the epithelium, exposing the cells to the surrounding air. Therefore, nutritive supply to the cells is warranted only by the basolateral cell pole. Under these conditions, the epithelial cells differentiate and regain full baso‐apical polarity. Some types of epithelia even generate in vivo‐like apical fluid or mucus. Interestingly, the ALI culture approach has also been shown to support morphological and functional differentiation of epithelial cells that are not normally exposed to ambient air in vivo. This review aims at giving a brief overview on the characteristics of ALI cultures in general and ALI models of female reproductive tract epithelia in particular. We discuss the applicability of ALI models for the investigation of the early embryonic microenvironment and for its implications in assisted reproductive technologies.

Replication of Severe Acute Respiratory Syndrome Coronavirus 2 in Human Respiratory Epithelium

“…Human airway epithelium (HAE) cultures reconstitute the tissue lining the conductive airways of humans. Being fully differentiated, they are among the best tools for studying viral infection in a natural microenvironment ( 15 ). These air-liquid interface cultures contain a number of cell types (e.g., basal, ciliated, and goblet).…”

Special review series on 3D organotypic culture models: Introduction and historical perspective

“…Skin epidermal keratinocytes undergo structural differentiation and the expression of keratin characteristic of skin epidermis under the influences of certain specific inducers on one hand (Cannon et al 1994) while in the absence of those inducers, differentiation occurs without cornification (as would be seen in the corneal epithelium) (Kaluzhny et al 2018). Interestingly, tissues such as the intestinal or vaginal epithelium respond to this induction even though these tissues do not experience an air-liquid interface during development (Chen and Schoen 2019) (Fig. 2).…”

“…The undifferentiated cells can be seeded and the population increased within the well until the growth factors are changed and differentiation of the epithelium begun. The critical step is the raising of the epithelial layer to the air-liquid interface to induce differentiation (Li et al 2016;Chen and Schoen 2019). This is achieved by removing the culture medium from the top compartment of the culture insert.…”

A long‐term in vitro culture of bovine epithelial cells on collagen rafts

“…On the other hand, free‐floating OEC vesicles with active cilia on their external surface can be cultured in common media but only for a short time (Rottmayer et al., 2006). Polarized ciliated and secretory OECs can be cultured for long‐term periods embedded in Matrigel with the apical side oriented towards the organoid lumen (Kessler et al., 2015), on permeable membrane inserts at air‐liquid interfaces (Chen & Schoen, 2019), and in microfluidic organ‐on‐a‐chip devices (Ferraz et al., 2018). In the present study, we developed a 3D primary bovine oviduct epithelial cells (BOECs) culture grown on free‐floating collagen hydrogels (rafts) at an air‐liquid interface (ALI); morphological and physiological features closely related to in vivo conditions were preserved under standard culture conditions.…”