In which anatomical area is filaggrin expressed?

Filaggrin is a protein that plays a critical role in the integrity of the skin barrier and is primarily expressed in the epidermis. It is important for maintaining hydration of the skin and for promoting the formation of the stratum corneum, the outermost layer of skin. In the context of the choices provided, the correct option, which names the anterior vestibulum of the nose, aligns with the knowledge that filaggrin can be found in certain areas of epithelial tissues that are involved in barrier function, including the nasal epithelium.

The anterior vestibulum of the nose is the part of the nasal cavity that acts as a barrier against environmental insults, such as allergens and pathogens, similar to the role of filaggrin in the skin. This region contains specialized epithelial cells that contribute to the protective functions of the nasal mucosa, aligning with the role that filaggrin plays in barrier integrity.

In contrast, while transitional and respiratory nasal epithelium play roles in the protection and function of the respiratory system, they do not specifically highlight or represent the typical function of filaggrin. Human bronchial epithelium also does not primarily express filaggrin, as its function is more focused on mucosal