Defects in mitochondrial clearance predispose human monocytes to interleukin-1ß hypersecretion.

Most hereditary periodic fever syndromes are mediated by deregulated IL-1ß secretion. The generation of mature IL-1ß requires two signals: one that induces synthesis of inflammasome components and substrates and a second that activates inflammasomes. The mechanisms that mediate autoinflammation in mevalonate kinase deficiency, a periodic fever disease characterized by a block in isoprenoid biosynthesis, are poorly understood. In studying the effects of isoprenoid shortage on IL-1 ß generation, we identified a new inflammasome activation signal that originates from defects in autophagy. We find that hypersecretion of IL-1ß and IL-18 requires reactive oxygen species and is associated with an oxidized redox status of monocytes but not lymphocytes. IL-1ß hypersecretion by monocytes involves decreased mitochondrial stability, release of mitochondrial content into the cytosol and attenuated autophagosomal degradation. Defective autophagy, as established by ATG7 knockdown, results in prolonged cytosolic retention of damaged mitochondria and increased IL-1ß secretion. Finally, activation of autophagy in healthy but not mevalonate kinase deficiency patient cells reduces IL-1ß secretion. Together, these results indicate that defective autophagy can prime monocytes for mitochondria-mediated NLRP3 inflammasome activation, thereby contributing to hypersecretion of IL-1ß in mevalonate kinase deficiency.

CBP/P300 Inhibition Impairs CD4+ T Cell Activation: Implications for Autoimmune Disorders.

T cell activation is critical for an effective immune response against pathogens. However, dysregulation contributes to the pathogenesis of autoimmune diseases, including Juvenile Idiopathic Arthritis (JIA). The molecular mechanisms underlying T cell activation are still incompletely understood. T cell activation promotes the acetylation of histone 3 at Lysine 27 (H3K27ac) at enhancer and promoter regions of proinflammatory cytokines, thereby increasing the expression of these genes which is essential for T cell function. Co-activators E1A binding protein P300 (P300) and CREB binding protein (CBP), collectively known as P300/CBP, are essential to facilitate H3K27 acetylation. Presently, the role of P300/CBP in human CD4+ T cells activation remains incompletely understood. To assess the function of P300/CBP in T cell activation and autoimmune disease, we utilized iCBP112, a selective inhibitor of P300/CBP, in T cells obtained from healthy controls and JIA patients. Treatment with iCBP112 suppressed T cell activation and cytokine signaling pathways, leading to reduced expression of many proinflammatory cytokines, including IL-2, IFN-γ, IL-4, and IL-17A. Moreover, P300/CBP inhibition in T cells derived from the inflamed synovium of JIA patients resulted in decreased expression of similar pathways and preferentially suppressed the expression of disease-associated genes. This study underscores the regulatory role of P300/CBP in regulating gene expression during T cell activation while offering potential insights into the pathogenesis of autoimmune diseases. Our findings indicate that P300/CBP inhibition could potentially be leveraged for the treatment of autoimmune diseases such as JIA in the future.

Restoring T Cell Tolerance, Exploring the Potential of Histone Deacetylase Inhibitors for the Treatment of Juvenile Idiopathic Arthritis.

Juvenile Idiopathic Arthritis (JIA) is characterized by a loss of immune tolerance. Here, the balance between the activity of effector T (Teff) cells and regulatory T (Treg) cells is disturbed resulting in chronic inflammation in the joints. Presently, therapeutic strategies are predominantly aimed at suppressing immune activation and pro-inflammatory effector mechanisms, ignoring the opportunity to also promote tolerance by boosting the regulatory side of the immune balance. Histone deacetylases (HDACs) can deacetylate both histone and non-histone proteins and have been demonstrated to modulate epigenetic regulation as well as cellular signaling in various cell types. Importantly, HDACs are potent regulators of both Teff cell and Treg cell function and can thus be regarded as attractive therapeutic targets in chronic inflammatory arthritis. HDAC inhibitors (HDACi) have proven therapeutic potential in the cancer field, and are presently being explored for their potential in the treatment of autoimmune diseases. Specific HDACi have already been demonstrated to reduce the secretion of pro-inflammatory cytokines by Teff cells, and promote Treg numbers and suppressive capacity in vitro and in vivo. In this review, we outline the role of the different classes of HDACs in both Teff cell and Treg cell function. Furthermore, we will review the effect of different HDACi on T cell tolerance and explore their potential as a therapeutic strategy for the treatment of oligoarticular and polyarticular JIA.

Intrapartum fever at term: diagnostic markers to individualize the risk of fetal infection: a review.

UNLABELLED: Intrauterine infection is a serious complication during labor at term and is associated with adverse neonatal outcome. Early and accurate diagnosis is of great concern for both obstetrician and pediatrician with the use of current diagnostics. Clinical symptoms are often regarded as the main sign of intrauterine infection but this approach is highly unreliable and leads to both under- and overtreatment. Currently, no distinct fetal heart rate (FHR) patterns have been found that reliably identify neonates with intrauterine infection. Using a systematic literature search, this article reviews possible markers for the early detection of intrauterine or neonatal infection in maternal serum, amniotic fluid, and umbilical cord blood during labor at term. Maternal serum markers, with the possible exception of interleukin (IL)-8, are unreliable for the detection of intrauterine infection. In contrast, amniotic fluid levels of especially IL-6 and IL-8 are significantly associated with intrauterine infection. Umbilical cord blood IL-6 has been extensively investigated and is usually elevated in case of intrauterine or neonatal infection but shows only modest positive and negative predictive values (NPVs) for clinical use. Umbilical cord IL-8 concentration could be a valuable addition in the diagnostic process, as it has shown to have an NPV of 84% to 92% in the detection of neonatal infection and histological chorioamnionitis. Future research is essential and should focus on the combination of different markers and on the development of a prediction model, to improve the positive and NPVs of our arsenal to detect intrauterine and neonatal infections. Amniotic fluid and umbilical cord values of IL-6 and IL-8 levels are likely candidates for such a prediction model. TARGET AUDIENCE: Obstetricians & Gynecologists and Family Physicians LEARNING OBJECTIVES: After the completing the CME activity, physicians should be better able to evaluate the use of clinical chorioamnionitis with regard to histological evidence and as a diagnostic tool in early diagnosis of intra-amniotic infection. Asses the use of amniotic fluid IL-6 and IL-8 as diagnostic tools to detect early intra-amniotic infection and assess umbilical cord blood IL-8 in case of intrauterine- or neonatal infection using positive (PPV) and negative predictive values (NPV).