CD150, also termed signaling lymphocyte activation molecule family member 1, is a cell surface receptor expressed on T cells, B cells, dendritic cells (DCs) and some tumors. Stimulation of CD150 on immune cells induces cell proliferation and cytokine production. However, the function of CD150 in Epstein‑Barr virus (EBV)‑infected B cells is still not fully understood. In the present study, CD150 expression on B cells increased rapidly following EBV infection, and various CD150 antibodies, measles viral proteins and recombinant CD150 proteins induced the secretion of multiple cytokines in both CD150+ EBV‑transformed B cells and EBV+ lymphoma cells. Notably, the IL‑1α protein level showed the greatest increase among all cytokines measured. The culture supernatant containing these cytokines induced the rapid differentiation of monocytes to DCs after only 2 days in vitro, which was faster than the established DC maturation time. Furthermore, knockdown of CD150 expression led to a reduction in the secretion of multiple cytokines, and monocyte differentiation was partially inhibited by anti‑IL‑1α and anti‑granulocyte‑macrophage colony‑stimulating factor neutralizing antibodies. Collectively, the results of the present study suggest that CD150 activation triggers cytokine production in EBV‑transformed B cells, and that measles virus coinfection might affect immune responses through the production of various cytokines in EBV+ lymphoma cells.

As a member of the Janus kinase (JAK) family, which includes JAK1, JAK2 and JAK3, tyrosine kinase 2 (TYK2) plays an important role in signal transduction and immune system regulation. Moreover, it is also involved in the development of many types of inflammatory and autoimmune diseases, such as psoriasis and systemic lupus erythematosus (SLE). TYK2 is an attractive therapeutic target, and selective inhibition of TYK2 over other JAK family members is critical for the development of TYK2 small molecule inhibitors. However, targeting the catalytic region of the TYK2 ATP-binding site is a major challenge due to the high structural homology between the catalytic regions of the JAK family proteins.
In this study, we developed a novel small molecule inhibitor (QL-1200186) by targeting the pseudokinase regulatory domain (Janus homology 2, JH2) of the TYK2 protein. The binding sites of QL-1200186 were predicted and screened by molecular docking. The inhibitory effects on IFNα, IL-12 and IL-23 signaling were tested in cell lines, human peripheral blood cells and human whole blood. The pharmacokinetic (PK) and pharmacodynamic properties of QL-1200186 were verified in mice. QL-1200186 showed high affinity for TYK2 JH2 and had no apparent selectivity for the TYK2 and JAK homologous kinase domains; these effects were demonstrated using biochemical binding, signaling pathway transduction (JAK1/2/3) and off-target effect assays. More importantly, we revealed that QL-1200186 was functionally comparable and selectivity superior to two clinical-stage TYK2 inhibitors (BMS-986165 and NDI-034858) in vitro. In the PK studies, QL-1200186 exhibited excellent exposure, high bioavailability and low clearance rates in mice. Oral administration of QL-1200186 dose-dependently inhibited interferon-γ (IFNγ) production after interleukin-12 (IL-12) challenge and significantly ameliorated skin lesions in psoriatic mice.
These findings suggest that QL-1200186 is a highly selective and potent inhibitor of TYK2. QL-1200186 could be an appealing clinical drug candidate for the treatment of psoriasis and other autoimmune diseases. Video Abstract.
© 2023. BioMed Central Ltd., part of Springer Nature.

Tyrosine kinase 2 (TYK2) is a member of the Janus kinase (JAK) family, which plays an important part in signal transduction and regulation of the immune system. To minimize the safety concerns and improve the therapeutic effect against autoimmune diseases, we developed a small molecule inhibitor (QL-1200186) targeting the pseudokinase domain of TYK2 protein (JH2). The binding sites of QL-1200186 were predicted and screened by molecular docking. The inhibitory effects of the downstream signaling pathways and transcriptional activators of TYK2 were reflected in cell lines and human peripheral-blood cells. Pharmacokinetics and pharmacodynamics were verified in mice. QL-1200186 showed highly affinity to TYK2 JH2 and had no apparent selectivity for the TYK2 and JAK homologous kinase domains (JH1); these effects were manifested in assays based on biochemical binding, signaling pathway transduction (JAK1/2/3) and off-target effects. We revealed that currently available drugs, such as BMS-986165 and NDI-034858, were the most likely candidates for TYK2 inhibitors, and found that QL-1200186 was functionally comparable to and selectively superior to both agents in vitro . QL-1200186 showed excellent exposure, high bioavailability and afforded low clearance rates in mice. Oral administration of QL-1200186 dose-dependently inhibited interferon-γ production in interleukin-12-driven responses and ameliorated skin lesions significantly in a mouse model of psoriasis, respectively. These findings suggest that QL-1200186 is a highly selective and potent inhibitor of TYK2. QL-1200186 could be developed as a drug for the treatment of psoriasis or other autoimmune diseases.

Parkinson's Disease (PD) is a neurodegenerative disease that affects the elderly. It is associated with motor dysfunction due to the accumulation of misfolded or aggregated fibrillar alpha-synuclein (α-syn) in the mid-brain. Current treatments are mainly focused on relieving the symptoms but are accompanied by side effects and are limited in halting disease progression. Increasing evidence points to peripheral immune cells underlying disease development, especially T cells contributing to α-syn-related neuroinflammation in PD. The onset of these cells is likely mediated by dendritic cells (DCs), whose role in α-syn-specific responses remain less studied. Moreover, Traditional Chinese medicine (TCM)-derived compounds that are candidates to treat PD may alleviate DC-T cell-mediated immune responses. Therefore, our study focused on the role of DC in response to fibrillar α-syn and subsequent induction of antigen-specific T cell responses, and the effect of TCM Curcumin-analog C1 and Tripterygium wilfordii Hook F-derived Celastrol. We found that although fibrillar α-syn did not induce significant inflammatory or T cell-mediating cytokines, robust pro-inflammatory T cell responses were found by co-culturing fibrillar α-syn-pulsed DCs with α-syn-specific CD4+ T cells. Celastrol, but not C1, reduced the onset of pro-inflammatory T cell differentiation, through promoting interaction of endosomal, amphisomal, and autophagic vesicles with fibrillar α-syn, which likely lead to its degradation and less antigen peptides available for presentation and T cell recognition. In conclusion, regulating the intracellular trafficking/processing of α-syn by DCs can be a potential approach to control the progression of PD, in which Celastrol is a potential candidate to accomplish this.
Copyright © 2022 Ng, Wang, Yang, Su, Li and Cheung.

Immunosurveillance of the gastrointestinal epithelium by mononuclear phagocytes (MNPs) is essential for maintaining gut health. However, studying the complex interplay between the human gastrointestinal epithelium and MNPs such as dendritic cells (DCs) is difficult, since traditional cell culture systems lack complexity, and animal models may not adequately represent human tissues. Microphysiological systems, or tissue chips, are an attractive alternative for these investigations, because they model functional features of specific tissues or organs using microscale culture platforms that recreate physiological tissue microenvironments. However, successful integration of multiple of tissue types on a tissue chip platform to reproduce physiological cell-cell interactions remains a challenge. We previously developed a tissue chip system, the gut organoid flow chip (GOFlowChip), for long term culture of 3-D pluripotent stem cell-derived human intestinal organoids. Here, we optimized the GOFlowChip platform to build a complex microphysiological immune-cell-epithelial cell co-culture model in order to study DC-epithelial interactions in human stomach. We first tested different tubing materials and chip configurations to optimize DC loading onto the GOFlowChip and demonstrated that DC culture on the GOFlowChip for up to 20 h did not impact DC activation status or viability. However, Transwell chemotaxis assays and live confocal imaging revealed that Matrigel, the extracellular matrix (ECM) material commonly used for organoid culture, prevented DC migration towards the organoids and the establishment of direct MNP-epithelial contacts. Therefore, we next evaluated DC chemotaxis through alternative ECM materials including Matrigel-collagen mixtures and synthetic hydrogels. A polysaccharide-based synthetic hydrogel, VitroGel®-ORGANOID-3 (V-ORG-3), enabled significantly increased DC chemotaxis through the matrix, supported organoid survival and growth, and did not significantly alter DC activation or viability. On the GOFlowChip, DCs that were flowed into the chip migrated rapidly through the V-ORG matrix and reached organoids embedded deep within the chip, with increased interactions between DCs and gastric organoids. The successful integration of DCs and V-ORG-3 embedded gastric organoids into the GOFlowChip platform now permits real-time imaging of MNP-epithelial interactions and other investigations of the complex interplay between gastrointestinal MNPs and epithelial cells in their response to pathogens, candidate drugs and mucosal vaccines.
Copyright © 2021 Cherne, Sidar, Sebrell, Sanchez, Heaton, Kassama, Roe, Gentry, Chang, Walk, Jutila, Wilking and Bimczok.