Choreographing Immunity in the Skin Epithelial Barrier

The Brain–Skin Connection and the Pathogenesis of Psoriasis: A Review with a Focus on the Serotonergic System

“…A recent paper reviewed the use of murine models to understand skin immunity, especially at the level of psoriasis, and stresses the main similarities and differences with human skin [22]. The skin immune system is composed of resident and recruited innate immune system (IIS) and adaptive immune system (AIS) cells that are activated by epidermal structures, microorganisms and other stimuli, and that crosstalk with skin cells, mainly KCs, in order to repair the skin barrier [23,24]. The initiation of immune responses in the skin is due to signals of the IIS, while the cells and signaling molecules of the AIS prolong inflammation [25].…”

“…It should be kept in mind that mammalian skin has a remarkable architectural heterogeneity, with different epidermal and dermal thickness, densities of hair follicles, sebaceous and sweat glands, microbiome, etc., and this is reflected in the composition of the immune cells in different skin areas. Hair follicles, for example, have their own unique epidermal and dermal immune microcosmos, and their KCs are essential for recruitment and retention of immune cells, in homeostasis or under stress [23].…”

“…Keratinocytes act not only as a physical barrier in the epidermis, but also have sensors that recognize foreign or microbial agents and tissue damage, through pattern recognition receptors which, upon stimulation, lead to the production of secondary mediators, such as antimicrobial peptides (AMPs) and pro-inflammatory chemokines and cytokines. These, in turn, promote AIS responses, particularly of the Th1 and Th17-type [23]. A dysregulation of AMP production seems to be a contributing factor for the development of autoimmune diseases, such as psoriasis [28] (Section 3.2).…”

27TH Fondation René Touraine Annual SCIENTIFIC MEETING 2019

“…Therefore, anyone interested in acquiring a fully balanced and comprehensive understanding of where the field currently stands is well‐advised to cast his/her literature search net wide and to complement this bibliography, which is largely restricted to 2018 and 2019 by consulting also relevant Focus Theme Issues and articles recently published in this journal, as well as recent reviews Ref . Only if complemented with such added skin appendage educationand food for thought can this bibliography hope to be useful.…”

Organoids in immunological research

“…For example, they are found in the skin, the gastrointestinal tract, the lungs and the thymus. Although haematopoietic cells are widely distributed throughout all tissues of the human body, the concentration of immune cells is highest in the epithelia (with the exception of the blood and lymphoid organs), where immune cells directly interact with epithelial cells [1][2][3] . These interactions have a role in both the maturation of immune cells (for example, in the thymus) and their activation (for example, upon wounding).…”