Tissue-resident memory T cells and their biological characteristics in the recurrence of inflammatory skin disorders

The skin is the largest organ of the body.The establishment of immunological memory in the skin is a crucial component of the adaptive immune response.Once naive T cells are activated by antigen-presenting cells,a small fraction of them differentiate into precursor memory T cells.These precursor cells ultimately develop into several subsets of memory T cells,including central memory T(TCM)cells,effector memory T(TEM)cells,and tissue resident memory T(TRM)cells.TRM cells have a unique transcriptional profile,and their most striking characteristics are their long-term survival(longevity)and low migration in peripheral tissues,including the skin.Under physiological conditions,TRM cells that reside in the skin can respond rapidly to pathogenic challenges.However,there is emerging evidence to support the vital role of TRM cells in the recurrence of chronic inflammatory skin disorders,including psoriasis,vitiligo,and fixed drug eruption,under pathological or uncontrolled conditions.Clarifying and characterizing the mechanisms that are involved in skin TRM cells will help provide promising strategies for reducing the frequency and magnitude of skin inflammation recurrence.Here,we discuss recent insights into the generation,homing,retention,and survival of TRM cells and share our perspectives on the biological characteristics of TRM cells in the recurrence of inflammatory skin disorders.

Koena, a Novel Compound That Dampens Inflammation in the Skin

Inflammatory skin diseases are characterized by the activation of the innate and adaptive immune system via the production of pro-inflammatory cytokines. The main proinflammatory cytokines responsible for this development include TNF-alpha, Interleukin 1, 6 and 17, also the transcription factor NF-kappa B. Small molecule anti-inflammatory compounds such as those detailed in the paper, show much promise in dealing with these skin disorders. Four nutraceutical molecules that are well characterized by their capacity to interact with many of the pro-inflammatory cytokines, importantly IL-17, are found in an Australian product, Koena. Koena has been shown to not only decrease these cytokines but also help increase the production of Interleukin 10 and important anti-inflammatory cytokines. This paper reports clinical benefits of Koena in a variety of circumstances;eczema and psoriasis;insect bites and sting;solar damaged skin and keratosis. An analysis of patient/purchaser reviews via the website Koena.com.au to ascertain what condition they purchased the product for, if any, and the satisfaction rating after use. More than 35% of reviewers reported purchasing Koena to help with inflamed skin. Those reporting being satisfied with the result was 95% for this use. This paper reports on the benefit of small molecule anti-inflammatories in modulating and not blocking an immune response. It also illustrates the benefits of multitherapy when dealing with complex inflammatory responses as opposed to monotherapy.

Transcription and Secretion of Interleukin-1β and HMGB1 in Keratinocytes Exposed to Stimulations Mimicking Common Inflammatory Damages

Objective:Interleukin-1β(IL-1β)and high-mobility group box 1(HMGB1)are widely known damage-associated molecular patterns(DAMPs).However,their expression and secretion in different skin diseases,especially in inflammatory skin disorders,remain to be further elucidated.This study was performed to explore and compare the transcriptional and secretory levels of IL-1β and HMGB1 in keratinocytes under 3 types of stimulation:ultraviolet B(UVB)irradiation;co-stimulation by tumor necrosis factor-α(TNF-α)and interferon-γ(IFN-γ)(simulation of T helper 1 cell inflammatory challenge);and psoriasis-like stimulation by M5,a mixture of 5 proinflammatory cytokines.Methods:We used quantitative reverse-transcription polymerase chain reaction to determine the transcription levels of IL-1β and HMGB1.Western blotting and enzyme-linked immunosorbent assay were used to detect the secretion levels of IL-1β and HMGB1.The results were statistically analyzed by t test.Results:A rapid transcriptional and secretory response of IL-1β from keratinocytes occurred in all 3 types of stimulation mimicking common inflammatory environments(P<0.05).Transcription of HMGB1 was inhibited in all 3 types of stimulation(P<0.05),but secretion was increased after exposure to UVB irradiation and co-stimulation by TNF-α and IFN-γ(P<0.05).We observed no change in the secretion level of HMGB1 after treatment with M5(P=0.196).Conclusion:IL-1β is a critical cytokine for the immunomodulatory functions of keratinocytes in inflammatory responses.In this study,keratinocytes restrained transcription of HMGB1 when the secretion of HMGB1 was induced in certain stimulations(eg,by UVB exposure or stimulation by TNF-α and IFN-γ).