CXCR5 is a key marker of follicular helper T (TFH) cells. Using primary lymph nodes (LNs) from HIV-infected patients, we identified a population of CXCR5- CD4+ T cells with TFH-cell-like features. This CXCR5- subset becomes expanded in severe HIV infection and is characterized by the upregulation of activation markers and high PD-1 and ICOS surface expression. Integrated analyses on the phenotypic heterogeneity, functional capacity, T cell receptor (TCR) repertoire, transcriptional profile, and epigenetic state of CXCR5-PD-1+ICOS+ T cells revealed a shared clonal relationship with TFH cells. CXCR5-PD-1+ICOS+ T cells retained a poised state for CXCR5 expression and exhibited a migratory transcriptional program. TCR sequence overlap revealed a contribution of LN-derived CXCR5-PD-1+ICOS+ T cells to circulating CXCR5- CD4+ T cells with B cell help function. These data link LN pathology to circulating T cells and expand the current understanding on the diversity of T cells that regulate B cell responses during chronic inflammation.
Published by Elsevier Inc.

Psoriasis is a chronic immune-mediated skin disease that involves the interaction of immune and skin cells, and is characterized by cytokine-driven epidermal hyperplasia, deviant differentiation, inflammation, and angiogenesis. Because the available treatments for psoriasis have significant limitations, dietary products are potential natural sources of therapeutic molecules, which can repair the molecular defects associated with psoriasis and could possibly be developed for its management. Fisetin (3,7,3',4'-tetrahydroxyflavone), a phytochemical naturally found in pigmented fruits and vegetables, has demonstrated proapoptotic and antioxidant effects in several malignancies. This study utilized biochemical, cellular, pharmacological, and tissue engineering tools to characterize the effects of fisetin on normal human epidermal keratinocytes (NHEKs), peripheral blood mononuclear cells (PBMC), and CD4+ T lymphocytes in 2D and 3D psoriasis-like disease models. Fisetin treatment of NHEKs dose- and time-dependently induced differentiation and inhibited interleukin-22-induced proliferation, as well as activation of the PI3K/Akt/mTOR pathway. Fisetin treatment of TNF-α stimulated NHEKs also significantly inhibited the activation of p38 and JNK, but had enhanced effect on ERK1/2 (MAPK). In addition, fisetin treatment significantly decreased the secretion of Th1/Th-17 pro-inflammatory cytokines, particularly IFN-γ and IL-17A by 12-O-tetradecanolylphorbol 13-acetate (TPA)-stimulated NHEKs and anti-CD3/CD28-activated human PBMCs. Furthermore, we established the in vivo relevance of fisetin functions, using a 3D full-thickness human skin model of psoriasis (FTRHSP) that closely mimics in vivo human psoriatic skin lesions. Herein, fisetin significantly ameliorated psoriasis-like disease features, and decreased the production of IL-17 by CD4+ T lymphocytes co-cultured with FTRHSP. Collectively, our data identify the prodifferentiative, antiproliferative, and anti-inflammatory effects of fisetin, via modulation of the PI3K-Akt-mTOR and p38/JNK pathways and the production of cytokines in 2D and 3D human skin models of psoriasis. These results suggest that fisetin has a great potential to be developed as an effective and inexpensive agent for the treatment of psoriasis and other related inflammatory skin disorders.

Poor vitamin D status is associated with a higher relapse rate and earlier disability in multiple sclerosis. Based on these associations, patients with multiple sclerosis are frequently supplemented with the vitamin D precursor cholecalciferol, although it is unclear whether this regimen is of therapeutic benefit. To model consequences of this common practice, mice were fed for more than 3 months with a low, medium or high dose of cholecalciferol, representative of vitamin D deficiency, modest and disproportionally high supplementation, respectively, in patients with multiple sclerosis. Compared to vitamin D-deprived mice, its moderate supplementation reduced the severity of subsequent experimental autoimmune encephalomyelitis, which was associated with an expansion of regulatory T cells. Direct exposure of murine or human T cells to vitamin D metabolites inhibited their activation. In contrast, mice with 25-(OH) vitamin D levels above 200 nmol/l developed fulminant experimental autoimmune encephalomyelitis with massive CNS infiltration of activated myeloid cells, Th1 and Th17 cells. When dissecting this unexpected outcome, we observed that high, but not medium dose vitamin D had caused mild hypercalcaemia, which rendered T cells more prone to pro-inflammatory activation. Exposing murine or human T cells to equivalent calcium concentrations in vitro enhanced its influx, triggering activation, upregulation of pro-inflammatory gene products and enhanced transmigration across a blood-brain barrier model. These findings suggest that vitamin D at moderate levels may exert a direct regulatory effect, while continuous high dose vitamin D treatment could trigger multiple sclerosis disease activity by raising mean levels of T-cell excitatory calcium.
© The Author(s) (2019). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

BACKGROUNDRecessive dystrophic epidermolysis bullosa (RDEB) is a severe form of skin fragility disorder due to mutations in COL7A1 encoding basement membrane type VII collagen (C7), the main constituent of anchoring fibrils (AFs) in skin. We developed a self-inactivating lentiviral platform encoding a codon-optimized COL7A1 cDNA under the control of a human phosphoglycerate kinase promoter for phase I evaluation.METHODSIn this single-center, open-label phase I trial, 4 adults with RDEB each received 3 intradermal injections (~1 × 106 cells/cm2 of intact skin) of COL7A1-modified autologous fibroblasts and were followed up for 12 months. The primary outcome was safety, including autoimmune reactions against recombinant C7. Secondary outcomes included C7 expression, AF morphology, and presence of transgene in the injected skin.RESULTSGene-modified fibroblasts were well tolerated, without serious adverse reactions or autoimmune reactions against recombinant C7. Regarding efficacy, there was a significant (P < 0.05) 1.26-fold to 26.10-fold increase in C7 mean fluorescence intensity in the injected skin compared with noninjected skin in 3 of 4 subjects, with a sustained increase up to 12 months in 2 of 4 subjects. The presence of transgene (codon-optimized COL7A1 cDNA) was demonstrated in the injected skin at month 12 in 1 subject, but no new mature AFs were detected.CONCLUSIONTo our knowledge, this is the first human study demonstrating safety and potential efficacy of lentiviral fibroblast gene therapy with the presence of COL7A1 transgene and subsequent C7 restoration in vivo in treated skin at 1 year after gene therapy. These data provide a rationale for phase II studies for further clinical evaluation.TRIAL REGISTRATIONClincalTrials.gov NCT02493816.FUNDINGCure EB, Dystrophic Epidermolysis Bullosa Research Association (UK), UK NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London, and Fondation René Touraine Short-Exchange Award.

CRTh2 (encoded by PTGDR2) is a G-protein coupled receptor expressed by Th2 cells as well as eosinophils, basophils and innate lymphoid cells (ILC)2s. Activation of CRTh2, by its ligand prostaglandin (PG)D2, mediates production of type 2 cytokines (IL-4, IL-5 and IL-13), chemotaxis and inhibition of apoptosis. As such, the PGD2-CRTh2 pathway is considered important to the development and maintenance of allergic inflammation. Expression of CRTh2 is mediated by the transcription factor GATA3 during Th2 cell differentiation and within ILC2s. Other than this, relatively little is known regarding the cellular and molecular mechanisms regulating expression of CRTh2. Here, we show using primary human Th2 cells that activation (24hrs) through TCR crosslinking (αCD3/αCD28) reduced expression of both mRNA and surface levels of CRTh2 assessed by flow cytometry and qRT-PCR. This effect took more than 4 hours and expression was recovered following removal of activation. EMSA analysis revealed that GATA3 and NFAT1 can bind independently to overlapping sites within a CRTh2 promoter probe. NFAT1 over-expression resulted in loss of GATA3-mediated CRTh2 promoter activity, while inhibition of NFAT using a peptide inhibitor (VIVIT) coincided with recovery of CRTh2 expression. Collectively these data indicate that expression of CRTh2 is regulated through the competitive action of GATA3 and NFAT1. Though prolonged activation led to NFAT1-mediated downregulation, CRTh2 was re-expressed when stimulus was removed suggesting this is a dynamic mechanism and may play a role in PGD2-CRTh2 mediated allergic inflammation.