The protein kinase Cθ (PKCθ) serine/threonine kinase has been implicated in signaling of T cell activation, proliferation, and cytokine production. However, the in vivo consequences of ablation of PKCθ on T cell function in inflammatory autoimmune disease have not been thoroughly examined. In this study we used PKCθ-deficient mice to investigate the potential involvement of PKCθ in the development of experimental autoimmune encephalomyelitis, a prototypic T cell-mediated autoimmune disease model of the CNS. We found that PKCθ−/− mice immunized with the myelin oligodendrocyte glycoprotein (MOG) peptide MOG35–55 were completely resistant to the development of clinical experimental autoimmune encephalomyelitis compared with wild-type control mice. Flow cytometric and histopathological analysis of the CNS revealed profound reduction of both T cell and macrophage infiltration and demyelination. Ex vivo MOG35–55 stimulation of splenic T lymphocytes from immunized PKCθ−/− mice revealed significantly reduced production of the Th1 cytokine IFN-γ as well as the T cell effector cytokine IL-17 despite comparable levels of IL-2 and IL-4 and similar cell proliferative responses. Furthermore, IL-17 expression was dramatically reduced in the CNS of PKCθ−/− mice compared with wild-type mice during the disease course. In addition, PKCθ−/− T cells failed to up-regulate LFA-1 expression in response to TCR activation, and LFA-1 expression was also significantly reduced in the spleens of MOG35–55-immunized PKCθ−/− mice as well as in in vitro-stimulated CD4+ T cells compared with wild-type mice. These results underscore the importance of PKCθ in the regulation of multiple T cell functions necessary for the development of autoimmune disease.

Vitamin D receptor (VDR) ligands are therapeutic agents for the treatment of psoriasis, osteoporosis, and secondary hyperparathyroidism. VDR ligands also show immense potential as therapeutic agents for autoimmune diseases and cancers of skin, prostate, colon, and breast as well as leukemia. However, the major side effect of VDR ligands that limits their expanded use and clinical development is hypercalcemia that develops as a result of the action of these compounds mainly on intestine. In order to discover VDR ligands with less hypercalcemia liability, we sought to identify tissue-selective VDR modulators (VDRMs) that act as agonists in some cell types and lack activity in others. Here, we describe LY2108491 and LY2109866 as nonsecosteroidal VDRMs that function as potent agonists in keratinocytes, osteoblasts, and peripheral blood mononuclear cells but show poor activity in intestinal cells. Finally, these nonsecosteroidal VDRMs were less calcemic in vivo, and LY2108491 exhibited more than 270-fold improved therapeutic index over the naturally occurring VDR ligand 1,25-dihydroxyvitamin D 3 [1,25-(OH) 2 D 3 ] in an in vivo preclinical surrogate model of psoriasis.

Hyperfunction of Th2 cells and aberrant glycosylation of IgA have been proposed independently as factors in the pathogenesis of IgA nephropathy (IgAN), the most common form of glomerulonephritis. To investigate the relationship between Th2 cytokines and IgA glycosylation in the genesis of IgAN, we induced IgAN in C3HeB and BALB/c mice by oral immunization and intranasal challenge with Sendai virus. Although both strains of mice developed microhaematuria and glomerular IgA immune deposits to similar degrees, only BALB/c mice developed significant renal insufficiency. More profound reductions of terminal galactosylation and sialylation occurred in Sendai virus‐specific IgA from BALB/c versus C3HeB mice, and splenocytes from immunized BALB/c mice produced more Th2 and less Th1 cytokines compared to C3HeB mice when stimulated with antigen in vitro. Furthermore, the decreased glycosylation of IgA elicited by Th2 cytokines in vitro was blunted by the addition of IFN‐γ. We conclude that increased production of Th2 cytokines can lead to abnormalities in IgA glycosylation, which in turn promote heightened phlogistic responses to IgA immune complexes lodging in the glomerulus. We suggest that a relative or absolute increase in Th2 cytokine production in response to mucosal infection is a significant pathogenic factor in human IgAN.

BACKGROUND/CONTEXT: Disc degeneration (DD) is a significant driver of low back pain and few treatments exist to treat the pain and disability associated with the disease. PURPOSE: Our group has developed a method to generate therapeutic discogenic cells as a potential treatment for symptomatic DD. These cells are derived and modified from adult nucleus pulposus cells. In this study, we evaluated the characteristics, mode of action, and in vivo efficacy and safety of these cells prior to human clinical testing. STUDY DESIGN: Privately funded in vitro studies and in vivo preclinical models were used in this study. METHODS: Discogenic cells generated from different adult human donors were evaluated for surface marker expression profile, matrix deposition and tumorigenic potential. Discogenic cells were then injected subcutaneously into nude mice to assess cell survival and possible extracellular matrix production in vivo. Finally, a rabbit model of DD was used to evaluate the therapeutic potential of discogenic cells after disc injury. RESULTS: We found that discogenic cells have a consistent surface marker profile, are multipotent for mesenchymal lineages, and produce extracellular matrix consisting of aggrecan, collagen 1 and collagen 2. Cells did not show abnormal karyotype after culturing and did not form tumor-like aggregates in soft agar. After subcutaneous implantation in a nude mouse model, the human discogenic cells were found to have generated regions rich with extracellular matrix over the course of 4 months, with no signs of tumorigenicity. Intradiscal injection of human discogenic cells in a rabbit model of DD caused an increase in disc height and improvement of tissue architecture relative to control discs or injection of vehicle alone (no cells) with no signs of toxicity. CONCLUSIONS: This study demonstrates that intradiscal injection of discogenic cells may be a viable treatment for human degenerative disc disease. The cells produce extracellular matrix that FDA device/drug status: Not applicable.

1alpha, 25-Dihydroxyvitamin D3 [1,25-(OH)2D3], the biologically active form of vitamin D, is an important hormone that is critically required for the maintenance of mineral homeostasis and structural integrity of bones. 1,25-(OH)2D3 accomplishes this by facilitating calcium absorption from the gut and by a direct action on osteoblasts, the bone forming cells. Apart form its classical actions on the gut and bone, 1,25-(OH)2D3 and its synthetic analogs also possess potent anti-proliferative, differentiative and immunomodulatory activities. 1,25-(OH)2D3 exerts these effects through vitamin D receptor (VDR), a ligand-dependent transcription factor that belongs to the superfamily of steroid/thyroid hormone/retinoid nuclear receptors. The presence of VDR in various tissues other than gut and bone, along with their ability to exert differentiation, growth inhibitory and anti-inflammatory action, has set the stage for therapeutic exploitation of VDR ligands for the treatment of various inflammatory indications and cancer. However, the use of VDR ligands in clinic is limited by their major dose-related side effect, namely hypercalcemia/hypercalciuria. Efforts are being undertaken to develop vitamin D receptor modulators (VDRMs) that are tissue-selective and/or gene-selective in their action and these ligands may exhibit increased therapeutic indices. This review explores the recent advances in VDR biology, non-secosteroidal VDR ligands and the current and potential clinical applications of VDR ligands in inflammation and cancer.