Discovery of a CCR2-targeting pepducin therapy for chronic pain.

Targeting the CCL2/CCR2 chemokine axis has been shown to be effective at relieving pain in rodent models of inflammatory and neuropathic pain, therefore representing a promising avenue for the development of non-opioid analgesics. However, clinical trials targeting this receptor for inflammatory conditions and painful neuropathies have failed to meet expectations and have all been discontinued due to lack of efficacy. To overcome the poor selectivity of CCR2 chemokine receptor antagonists, we generated and characterized the function of intracellular cell-penetrating allosteric modulators targeting CCR2, namely pepducins.

Regulatory T cell-derived enkephalin gates nociception.

T cells have emerged as sex-dependent orchestrators of pain chronification but the sexually dimorphic mechanisms by which T cells control pain sensitivity is not resolved. Here, we demonstrate an influence of regulatory T cells (Tregs) on pain processing that is distinct from their canonical functions of immune regulation and tissue repair. Specifically, meningeal Tregs (mTregs) express the endogenous opioid, enkephalin, and mTreg-derived enkephalin exerts an antinociceptive action through a presynaptic opioid receptor signaling mechanism that is dispensable for immunosuppression.

Local IL-23 is required for proliferation and retention of skin-resident memory T17 cells.

The cytokine interleukin-23 (IL-23) is critical for development and maintenance of autoimmune inflammation in nonlymphoid tissues; however, the mechanism through which IL-23 supports tissue-specific immunity remains unclear. In mice, we found that circulating memory T cells were dispensable for anamnestic protection from skin infection, and tissue-resident memory (T) cell-mediated protection from reinfection required IL-23. Administration of anti-IL-23 receptor antibody to mice after resolution of primary infection resulted in loss of CD69 CD103 tissue-resident memory T helper 17 (T) cells from skin, and clinical anti-IL-23 therapy depleted T cells from skin of patients with psoriasis.

Single-Cell Profiling Reveals Divergent, Globally Patterned Immune Responses in Murine Skin Inflammation.

Inflammatory response heterogeneity has impeded high-resolution dissection of diverse immune cell populations during activation. We characterize mouse cutaneous immune cells by single-cell RNA sequencing, after inducing inflammation using imiquimod and oxazolone dermatitis models. We identify 13 CD45 subpopulations, which broadly represent most functionally characterized immune cell types.

Isolation of Murine Skin Resident and Migratory Dendritic Cells via Enzymatic Digestion.

Dendritic cells (DCs) are a highly specialized subset of professional antigen-presenting cells (APCs) that reside in peripheral and lymphoid tissues. DCs capture antigen in the periphery and migrate to the lymph node where they prime naïve T cells. In addition, DCs have been recently appreciated to have function in innate immunity within tissues.

Inflammatory arthritis in pediatric patients with morphea.

Background: Morphea or localized scleroderma is an inflammatory disorder resulting in fibrosis of the skin and subcutaneous tissues. Joint contractures, arthralgias, and functional compromise are recognized associations of pediatric morphea. The co-existence of inflammatory arthritis and morphea is not well-described in the literature.

Antigen-Presenting Cells in the Skin.

Professional antigen-presenting cells (APCs) in the skin include dendritic cells, monocytes, and macrophages. They are highly dynamic, with the capacity to enter skin from the peripheral circulation, patrol within tissue, and migrate through lymphatics to draining lymph nodes. Skin APCs are endowed with antigen-sensing, -processing, and -presenting machinery and play key roles in initiating, modulating, and resolving cutaneous inflammation.

Pathogenic and Protective Autoantibodies in Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED).

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare disorder caused by mutations in the autoimmune regulator () gene, leading to defects in T cell selection. The disease manifestations include both autoimmune tissue destruction and immunodeficiency, with specific susceptibility to chronic mucocutaneous candidiasis. Studies have demonstrated a wide repertoire of high affinity tissue- and cytokine-specific antibodies in patients with APECED.

Different Lymphocyte Populations Direct Dichotomous Eosinophil or Neutrophil Responses to Pulmonary Cryptococcus Infection.

Many pulmonary infections elicit lymphocyte responses that lead to an accumulation of granulocytes in the lungs. A variety of lymphocytes are capable of directing eosinophils or neutrophils to the lungs, but the contribution of each subset remains enigmatic. In this study, we used a murine model to examine lymphocyte subsets that ultimately drive the eosinophil or neutrophil response to infection with the fungal pathogen Cryptococcus neoformans.

Skin Immunity to Candida albicans.

Candida albicans is a dimorphic commensal fungus that colonizes healthy human skin, mucosa, and the reproductive tract. C. albicans is also a predominantly opportunistic fungal pathogen, leading to disease manifestations such as disseminated candidiasis and chronic mucocutaneous candidiasis (CMC).

Stromal cells control the epithelial residence of DCs and memory T cells by regulated activation of TGF-β.

Cells of the immune system that reside in barrier epithelia provide a first line of defense against pathogens. Langerhans cells (LCs) and CD8(+) tissue-resident memory T cells (TRM cells) require active transforming growth factor-β1 (TGF-β) for epidermal residence. Here we found that integrins αvβ6 and αvβ8 were expressed in non-overlapping patterns by keratinocytes (KCs) and maintained the epidermal residence of LCs and TRM cells by activating latent TGF-β.

Brief Report: Arthritis in KRN T Cell Receptor-Transgenic Mice Does Not Require Interleukin-17 or Th17 Cells.

Objective: Th17 cells and interleukin-17 (IL-17) cytokine family members are implicated in the pathogenesis of many rheumatic diseases. Most studies in mouse models of inflammatory arthritis have demonstrated a key role for the proinflammatory cytokine IL-17A and its receptor, the IL-17 receptor (IL-17R) A/C heterodimer. The aim of this study was to use a rigorous genetic approach to evaluate the contribution of Th17 cells and IL-17 in the autoantibody-dependent KRN T cell receptor-transgenic mouse model of arthritis.

Generation of Th17 cells in response to intranasal infection requires TGF-β1 from dendritic cells and IL-6 from CD301b+ dendritic cells.

Intranasal (i.n.) infections preferentially generate Th17 cells.

Nociceptive Sensory Fibers Drive Interleukin-23 Production from CD301b+ Dermal Dendritic Cells and Drive Protective Cutaneous Immunity.

Innate resistance to Candida albicans in mucosal tissues requires the production of interleukin-17A (IL-17A) by tissue-resident cells early during infection, but the mechanism of cytokine production has not been precisely defined. In the skin, we found that dermal γδ T cells were the dominant source of IL-17A during C. albicans infection and were required for pathogen resistance.

Candida albicans morphology and dendritic cell subsets determine T helper cell differentiation.

Candida albicans is a dimorphic fungus responsible for chronic mucocutaneous and systemic infections. Mucocutaneous immunity to C. albicans requires T helper 17 (Th17) cell differentiation that is thought to depend on recognition of filamentous C.

Alterations in antigen-specific naive CD4 T cell precursors after sepsis impairs their responsiveness to pathogen challenge.

Patients surviving the acute stages of sepsis develop compromised T cell immunity and increased susceptibility to infection. Little is known about the decreased CD4 T cell function after sepsis. We tracked the loss and recovery of endogenous Ag-specific CD4 T cell populations after cecal ligation and puncture-induced sepsis and analyzed the CD4 T cell response to heterologous infection during or after recovery.

G protein coupled receptor specificity for C3a and compound 48/80-induced degranulation in human mast cells: roles of Mas-related genes MrgX1 and MrgX2.

Although human mast cells express G protein coupled receptors for the anaphylatoxin C3a, previous studies indicated that C3a causes mast cell degranulation, at least in part, via a C3a receptor-independent mechanism similar to that proposed for polycationic molecules such as compound 48/80. The purpose of the present study was to delineate the receptor specificity of C3a-induced degranulation in human mast cells. We found that C3a, a C3a receptor "superagonist" (E7) and compound 48/80 induced Ca(2+) mobilization and degranulation in a differentiated human mast cell line, LAD2.

PMX-53 as a dual CD88 antagonist and an agonist for Mas-related gene 2 (MrgX2) in human mast cells.

Human mast cells express the G protein coupled receptor (GPCR) for C5a (CD88). Previous studies indicated that C5a could cause mast cell degranulation, at least in part, via a mechanism similar to that proposed for basic neuropeptides such as substance P, possibly involving Mas-related gene 2 (MrgX2). We therefore sought to more clearly define the receptor specificity for C5a-induced mast cell degranulation.

Antithrombotic activity of kininogen is mediated by inhibitory effects of domain 3 during arterial injury in vivo.

High-molecular-weight kininogen (HK) and its domain 3 (D3) exhibit anticoagulant properties and inhibit platelet activation at low thrombin concentration in vitro. We hypothesized that the rapid occlusive thrombosis in HK-deficient (HKd) rats following endothelial injury of the aorta results from enhanced platelet aggregation by thrombin. The effects of D3 (G235-M357) or D3-derived peptides on thrombosis in vivo were tested.