c-Jun N-Terminal Kinase in Inflammation and Rheumatic Diseases.

The c-Jun N-terminal kinases (JNKs) are members of the mitogen-activated protein kinase (MAPK) family and are activated by environmental stress. JNK is also activated by proinflammatory cytokines, such as TNF and IL-1, and Toll-like receptor ligands. This pathway, therefore, can act as a critical convergence point in immune system signaling for both adaptive and innate responses. Like other MAPKs, the JNKs are activated via the sequential activation of protein kinases that includes two dual-specificity MAP kinase kinases (MKK4 and MKK7) and multiple MAP kinase kinase kinases. MAPKs, including JNKs, can be deactivated by a specialized group of phosphatases, called MAP kinase phosphatases. JNK phosphorylates and regulates the activity of transcription factors other than c-Jun, including ATF2, Elk-1, p53 and c-Myc and non-transcription factors, such as members of the Bcl-2 family. The pathway plays a critical role in cell proliferation, apoptosis, angiogenesis and migration. In this review, an overview of the functions that are related to rheumatic diseases is presented. In addition, some diseases in which JNK participates will be highlighted

'Rac'-ing upstream to treat rheumatoid arthritis

Signal transduction pathways regulate the production and function of many cytokines implicated in immune-mediated diseases. Targeting these enzymes with small molecule inhibitors represents a fertile field for the treatment of rheumatoid arthritis. Recent successes with compounds that block upstream kinases suggest that proximal members of the signaling cascades, such as Rac and other Rho family enzymes, might have therapeutic potential. Balancing efficacy and toxicity, however, remains a significant challenge that will require careful evaluation

Development of a game-based learning tool for applied team science communication in a virtual clinical trial.

Educational tools for application of team science competencies in clinical research are needed. Our interdisciplinary group developed and evaluated acceptability of a virtual world game-based learning tool simulating a multisite clinical trial; performance hinges on effective intrateam communication. Initial implementation with clinical research trainees (n=40) indicates high satisfaction and perceived relevance to team science and research career goals. Game-based learning may play an important role in team science training

Differential regulation of anti-inflammatory genes by p38 MAP kinase and MAP kinase kinase 6.

BackgroundConventional p38α inhibitors have limited efficacy in rheumatoid arthritis, possibly because p38 blockade suppresses the counter-regulatory mechanisms that limit inflammation. In contrast, targeting the upstream MAP kinase kinases, MKK3 and MKK6, partially maintains p38-mediated anti-inflammatory responses in bone marrow-derived macrophages (BMDM). In this study, we explored the mechanisms that preserve anti-inflammatory gene expression by evaluating differential regulation of IL-10 and p38-dependent anti-inflammatory genes in MKK3-/-, MKK6-/-, and p38 inhibitor-treated wildtype cells.MethodsBMDM from wild type (WT), MKK3-/-, and MKK6-/- mice were pre-treated with p38 inhibitor SB203580 (SB), JNK inhibitor SP600125 (SP), and/or ERK inhibitor PD98059 (PD) and stimulated with LPS. Supernatant protein levels were measured by multiplex bead immunoassay. mRNA expression was determined by qPCR and protein expression by Western blot analysis. De novo IL-10 mRNA synthesis was quantified in cells treated with ethynyl-uridine and LPS followed by reverse transcription and qPCR. mRNA half-life was measured in LPS-treated cells that were then incubated with actinomycin D ± SB203580.ResultsPre-treatment of WT BMDM with p38 inhibitor significantly reduced IL-10 production in the three groups, while ERK and JNK inhibitors had minimal effects. IL-10 production was significantly decreased in MKK3-/- BMDM compared with either WT or MKK6-/- cells. IL-10 mRNA expression was modestly reduced in MKK3-/- BMDM but was preserved in MKK6-/- cells compared with WT. De novo IL-10 mRNA synthesis was inhibited in MKK3-/- and p38 inhibitor pre-treated cells, but not MKK6-/- cells compared with WT. IL-10 mRNA half-life was markedly reduced in p38 inhibitor-treated WT cells while MKK-deficiency had minimal effect. DUSP1 mRNA levels were preserved in MKK-deficient cells but not in p38 inhibitor-treated WT cells. Tristetraprolin mRNA and protein levels were reduced in p38 inhibitor-treated WT cells compared with MKK6-/- cells.ConclusionUnlike p38-inhibition, the absence of MKK6 mostly preserves IL-10 and TTP protein expression in BMDM. MKK6-deficiency also spares DUSP1 and IL-1RA, which are key negative regulators of the inflammatory response. Together, these data suggest that MKK6 is a potential therapeutic target in RA

Regulation of the JNK pathway by TGF-beta activated kinase 1 in rheumatoid arthritis synoviocytes.

c-Jun N-terminal kinase (JNK) contributes to metalloproteinase (MMP) gene expression and joint destruction in inflammatory arthritis. It is phosphorylated by at least two upstream kinases, the mitogen-activated protein kinase kinases (MEK) MKK4 and MKK7, which are, in turn, phosphorylated by MEK kinases (MEKKs). However, the MEKKs that are most relevant to JNK activation in synoviocytes have not been determined. These studies were designed to assess the hierarchy of upstream MEKKs, MEKK1, MEKK2, MEKK3, and transforming growth factor-beta activated kinase (TAK)1, in rheumatoid arthritis (RA). Using either small interfering RNA (siRNA) knockdown or knockout fibroblast-like synoviocytes (FLSs), MEKK1, MEKK2, or MEKK3 deficiency (either alone or in combination) had no effect on IL-1beta-stimulated phospho-JNK (P-JNK) induction or MMP expression. However, TAK1 deficiency significantly decreased P-JNK, P-MKK4 and P-MKK7 induction compared with scrambled control. TAK1 knockdown did not affect p38 activation. Kinase assays showed that TAK1 siRNA significantly suppressed JNK kinase function. In addition, MKK4 and MKK7 kinase activity were significantly decreased in TAK1 deficient FLSs. Electrophoretic mobility shift assays demonstrated a significant decrease in IL-1beta induced AP-1 activation due to TAK1 knockdown. Quantitative PCR showed that TAK1 deficiency significantly decreased IL-1beta-induced MMP3 gene expression and IL-6 protein expression. These results show that TAK1 is a critical pathway for IL-1beta-induced activation of JNK and JNK-regulated gene expression in FLSs. In contrast to other cell lineages, MEKK1, MEKK2, and MEKK3 did not contribute to JNK phosphorylation in FLSs. The data identify TAK1 as a pivotal upstream kinase and potential therapeutic target to modulate synoviocyte activation in RA

Garden of therapeutic delights: new targets in rheumatic diseases

Advances in our understanding of the cellular and molecular mechanisms in rheumatic disease fostered the advent of the targeted therapeutics era. Intense research activity continues to increase the number of potential targets at an accelerated pace. In this review, examples of promising targets and agents that are at various stages of clinical development are described. Cytokine inhibition remains at the forefront with the success of tumor necrosis factor blockers, and biologics that block interleukin-6 (IL-6), IL-17, IL-12, and IL-23 and other cytokines are on the horizon. After the success of rituximab and abatacept, other cell-targeted approaches that inhibit or deplete lymphocytes have moved forward, such as blocking BAFF/BLyS (B-cell activation factor of the tumor necrosis factor family/B-lymphocyte stimulator) and APRIL (a proliferation-inducing ligand) or suppressing T-cell activation with costimulation molecule blockers. Small-molecule inhibitors might eventually challenge the dominance of biologics in the future. In addition to plasma membrane G protein-coupled chemokine receptors, small molecules can be designed to block intracellular enzymes that control signaling pathways. Inhibitors of tyrosine kinases expressed in lymphocytes, such as spleen tyrosine kinase and Janus kinase, are being tested in autoimmune diseases. Inactivation of the more broadly expressed mitogen-activated protein kinases could suppress inflammation driven by macrophages and mesenchymal cells. Targeting tyrosine kinases downstream of growth factor receptors might also reduce fibrosis in conditions like systemic sclerosis. The abundance of potential targets suggests that new and creative ways of evaluating safety and efficacy are needed

Regulation of Peripheral Inflammation by the Central Nervous System

In inflammatory disorders such as rheumatoid arthritis, cytokines and danger signals are sensed by the central nervous system, which adapts behavior and physiologic responses during systemic stress. The central nervous system can also signal the periphery to modulate inflammation through efferent hormonal and neuronal pathways. The brain and spinal cord are involved in this bidirectional interaction. A variety of neuronal pathways that modulate synovial inflammation have been implicated, including the sympathetic and the parasympathetic branches of the autonomic system. Another mechanism, the dorsal root reflex, involves antidromic signaling along somatic afferent fibers that influences joint inflammation by releasing neuropeptides and other neuromediators in the periphery. Some of the neurotransmitters and neuroreceptors involved have been identified in preclinical models and represent novel targets for the treatment of rheumatic diseases

Systems approach to assessing and improving local human research Institutional Review Board performance.

ObjectiveTo quantifying the interdependency within the regulatory environment governing human subject research, including Institutional Review Boards (IRBs), federally mandated Medicare coverage analysis and contract negotiations.MethodsOver 8000 IRB, coverage analysis and contract applications initiated between 2013 and 2016 were analyzed using traditional and machine learning analytics for a quality improvement effort to improve the time required to authorize the start of human research studies.ResultsStaffing ratios, study characteristics such as the number of arms, source of funding and number and type of ancillary reviews significantly influenced the timelines. Using key variables, a predictive algorithm identified outliers for a workflow distinct from the standard process. Improved communication between regulatory units, integration of common functions, and education outreach improved the regulatory approval process.ConclusionsUnderstanding and improving the interdependencies between IRB, coverage analysis and contract negotiation offices requires a systems approach and might benefit from predictive analytics