Project description:RNA sequencing was used to compare the transcriptional state of ex-vivo B-cells from children with Juvenile dermatomyositis (JDM) pre- and on-treatment and age-matched healthy controls. RNA was extracted from blood samples that were taken from juvenile dermatomyositis patients at diagnosis (before they received treatment) and approximately a year into treatment. The treatment included oral prednisolone, methotrexate, azathioprine, cyclophosphamide and other drugs.
Project description:Total RNA from peripheral blood mononuclear cells (PBMC) and neutrophils from children with juvenile dermatomyositis (JDM) and juvenile idiopathic arthritis (JIA) were separately compared to pediatric control samples. Keywords: pediatric rheumatic disease, blood, PBMC, neutrophil, JIA, JDM
Project description:RNA sequencing was used to compare the transcriptional state of ex-vivo B-cells, moncytes and T-cells from children with Juvenile dermatomyositis (JDM) pre- and on-treatment and age-matched healthy controls. RNA was extracted from blood samples that were taken from juvenile dermatomyositis patients at diagnosis (before they received treatment) and approximately a year into treatment. The treatment included oral prednisolone, methotrexate, azathioprine, cyclophosphamide and other drugs.
Project description:Total RNA from peripheral blood mononuclear cells (PBMC) and neutrophils from children with juvenile dermatomyositis (JDM) and juvenile idiopathic arthritis (JIA) were separately compared to pediatric control samples. Keywords: pediatric rheumatic disease, blood, PBMC, neutrophil, JIA, JDM JIA PBMC n = 14 JIA neutrophils n=14 JDM PBMC n = 13 JDM neutrophils n = 14 pediatric control PBMC n = 15 pediatric control neutrophils n = 13
Project description:Background :To evaluate the impact of the duration of chronic inflammation on gene expression in skeletal muscle biopsies (MBx) from untreated children with juvenile dermatomyositis (JDM) and identify genes and biological processes associated with the disease progression, expression profiling data from 16 girls with active symptoms of JDM greater or equal to 2 months were compared with 3 girls with active symptoms less than 2 months. Results: Seventy-nine genes were differentially expressed between the groups with long or short duration of untreated disease. Genes involved in immune responses and vasculature remodeling were expressed at a higher level in muscle biopsies from children with greater or equal to 2 months of symptoms, while genes involved in stress responses and protein turnover were expressed at a lower level. Among the 79 genes, expression of 9 genes showed a significant linear regression relationship with the duration of untreated disease. Five differentially expressed genes--HLA-DQA1, smooth muscle myosin heavy chain, clustering, plexin D1 and tenomodulin--were verified by quantitative RT-PCR. The chronic inflammation of longer disease duration was also associated with increased DC-LAMP+ and BDCA2+ mature dendritic cells, identified by immunohistochemistry. Conclusions: We conclude that chronic inflammation alters the gene expression patterns in muscle of untreated children with JDM. Symptoms lasting greater or equal to 2 months were associated with dendritic cell maturation and anti-angiogenic vascular remodelling, directly contributing to disease pathophysiology. Keywords: Disease progression; time course
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:To better understand the pathogenesis of juvenile dermatomyositis (JDM) we examined the genetic alterations that result from exogenous IFN I exposure in pediatric skeletal muscle. We compared untreated healthy pediatric donor-derived myobundles with those treated with IFN I as well as with JAKi baricitinib and tofacitinib. We used bulk mRNA sequencing to evaluate how IFN I and treatment with JAKi influence healthy and JDM skeletal muscle gene expression and show IFNβ leads to a greater pro-inflammatory gene response than IFNα in pediatric skeletal muscle. As a type I interferon gene signature is established in JDM, downregulated oxidative phosphorylation, myogenesis, and contractile protein gene expression is implicated in JDM pathology. These genetic changes are partially reversed by JAK inhibitors, baricitinib and tofacitinib, with baricitinib leading to greater genetic alteration than tofacitinib. Our findings show that analysis of differential gene expression in bioengineered pediatric skeletal muscle can inform our knowledge of JDM pathogenesis and therapeutic effects.