Biology subjects

Linley, H.

Publications and source records attributed to Linley, H..

3 recordsLinked to original sources

bioRxiv2025

CD200R1 is required for the development of γδ 17 T cells

{gamma}{delta} T cells are enriched at barrier sites such as skin, gut and lung, where they protect against cancer and infections and promote healing. They detect diverse ligands in T cell receptor-dependent or independent manners, producing large quantities of pro-inflammatory cytokines. {gamma}{delta} T cells develop in foetal thymi in temporally controlled waves where, unlike {beta} T cells, many {gamma}{delta} T cells adopt their effector fate, becoming either IFN{gamma} or IL-17A-producers ({gamma}{delta}17 T cells). CD200R1 suppresses myeloid cell activity but has also been shown to promote innate lymphoid cell IL-17A production, enhancing psoriasis-like skin inflammation. {gamma}{delta}17 T cells are potent IL-17A producers in skin therefore, the effect of CD200R1 on IL-17A production by {gamma}{delta}17 T cells was investigated. CD200R1 was found to promote IL-17A production by {gamma}{delta} T cells by supporting the development of {gamma}{delta}17 T cells, enhancing IL-17-producing and ROR{gamma}t+ {gamma}{delta} T cell numbers in foetal thymic organ cultures. To fulfil this role, CD200R1 acts either directly on developing {gamma}{delta} T cells, or indirectly on thymic stromal cells. This identifies CD200R1 as a critical novel regulator of {gamma}{delta}17 T cell development in early life, a key process for ensuring immunity, particularly at barrier sites.

immunology↗

bioRxiv2022

CD200R1 promotes IL-17 production by ILC3s, by enhancing STAT3 activation

Psoriasis is a common chronic inflammatory skin disease with no cure. It is driven by the IL-23/IL-17A axis and TH17 cells but, recently group 3 innate lymphoid cells (ILC3s) have also been implicated. However, the development, and factors regulating the activity of ILC3s remain incompletely understood. Immune regulatory pathways are particularly important at barrier sites such as the skin, gut and lung, which are exposed to environmental substances and microbes. CD200R1 is an immune regulatory cell surface receptor which inhibits proinflammatory cytokine production in myeloid cells. CD200R1 is also highly expressed on ILCs, where its function remains largely unexplored. We previously observed reduced CD200R1 signalling in psoriasis skin, suggesting that dysregulation may promote disease. Here we show that contrary to this, psoriasis models are less severe in CD200R1-deficient mice due to reduced IL-17 production. Here we uncover a key cell-intrinsic role for CD200R1 in promoting IL-23-driven IL-17A production by ILC3s, by promoting STAT3 activation. CD200R1 is expressed on ILC precursors and is particularly high on neonatal ILC3s, suggesting CD200R1 may function during ILC development. Therefore, CD200R1 is required on ILC3s, potentially during their development, to promote IL-23-stimulated STAT3 activation triggering optimal IL-17 production.

immunology↗

bioRxiv2022

Reduced cutaneous CD200:CD200R1 signalling in psoriasis enhances neutrophil recruitment to skin

The skin immune system is tightly regulated to prevent inappropriate inflammation in response to harmless environmental substances. This regulation is actively maintained by mechanisms including cytokines and cell surface receptors and its loss results in inflammatory disease. In the case of psoriasis, inappropriate immune activation leads to IL-17-driven chronic inflammation, but molecular mechanisms underlying this loss of regulation are not well understood. We reveal that immunoglobulin superfamily member CD200, and signalling via its receptor, CD200R1 are reduced in non-lesional psoriasis skin. To examine the consequences of this, CD200R1 was blocked in a mouse model of psoriasis demonstrating that the receptor limits psoriasis-like inflammation. Specifically, CD200R1 blockade enhances acanthosis, CCL20 production and neutrophil recruitment but surprisingly, macrophage function and IL-17 production were not affected, and neutrophil reactive oxygen species production was reduced. Collectively, our data show that CD200R1 affects neutrophil function and limits inflammatory responses in healthy skin by restricting neutrophil recruitment. However, the CD200 pathway is reduced in psoriasis, resulting in a loss of immune control, and increased neutrophil recruitment in mouse models. In conclusion, we highlight a pathway that might be targeted to dampen inflammation in patients with psoriasis.

immunology↗