👤 Simon Arthur

Macrophages are key cells in the pathogenesis of chronic inflammatory diseases. Interleukin (IL)-27 is a pleiotropic cytokine with mostly immunoregulatory functions and associated with a wide array of diseases. There is little knowledge on the effects of IL-27 on human macrophages. Here, we characterise the effect of IL-27 on human blood derived CD14+ monocyte derived macrophages (MDMs), in resting state and under inflammatory stimulation (+LPS/PepG), through targeted transcriptomic expression profile, phagocytosis of E. coli bioparticles and expression of intracellular and secreted proteins by DIA mass spectrometry and multiplex ELISA, respectively. There was no change in pro-inflammatory cytokine gene expression with IL-27. IL-27 led to changes in the chemokine secretome, inducing a significant upregulation of the chemokines CXCL9 and CXCL10 and reduced expression of CCL2, CCL7, CCL13, CCL18, CCL24, CXCL13, IL-10 and Midkine. Macrophage phagocytosis was not affected by IL-27. IL-27 effects on intracellular proteome were subtle overall. Using unadjusted p values, changes were most pronounced in the resting state, with a significant (p < 0.05) increase in 106 and decrease in 11 proteins. Enrichment analysis suggested regulation of several biological processes by IL-27, including cellular response to type II interferon. Overall, we demonstrate novel biology of IL-27 mediated effects in human macrophages. Show less

Low-grade gliomas (LGGs) represent children's most prevalent central nervous system tumor, necessitating molecular profiling to diagnose and determine the most suitable treatment. Developing highly sensitive screening techniques for liquid biopsy samples is particularly beneficial, as it enables the early detection and molecular characterization of tumors with minimally invasive samples. We examined CSF and plasma samples from patients with pilocytic astrocytoma (PA) using custom multiplexed droplet digital polymerase chain reaction (ddPCR) assays based on whole genome sequencing data. These assays included a screening test to analyze Our findings revealed that 5 out of 13 individual cerebrospinal fluid (CSF) samples tested positive for circulating tumor DNA (ctDNA). Among these cases, 3 exhibited the While CNV analysis of CSF samples from LGGs still has some limitations, it has the potential to serve as a valuable complementary tool. Furthermore, it can also be multiplexed with other aberrations, for example, to the Show less

The RNA binding protein T-STAR was created following a gene triplication 520-610 million years ago, which also produced its two parologs Sam68 and SLM-1. Here we have created a T-STAR null mouse to identify the endogenous functions of this RNA binding protein. Mice null for T-STAR developed normally and were fertile, surprisingly, given the high expression of T-STAR in the testis and the brain, and the known infertility and pleiotropic defects of Sam68 null mice. Using a transcriptome-wide search for splicing targets in the adult brain, we identified T-STAR protein as a potent splicing repressor of the alternatively spliced segment 4 (AS4) exons from each of the Neurexin1-3 genes, and exon 23 of the Stxbp5l gene. T-STAR protein was most highly concentrated in forebrain-derived structures like the hippocampus, which also showed maximal Neurexin1-3 AS4 splicing repression. In the absence of endogenous T-STAR protein, Nrxn1-3 AS4 splicing repression dramatically decreased, despite physiological co-expression of Sam68. In transfected cells Neurexin3 AS4 alternative splicing was regulated by either T-STAR or Sam68 proteins. In contrast, Neurexin2 AS4 splicing was only regulated by T-STAR, through a UWAA-rich response element immediately downstream of the regulated exon conserved since the radiation of bony vertebrates. The AS4 exons in the Nrxn1 and Nrxn3 genes were also associated with distinct patterns of conserved UWAA repeats. Consistent with an ancient mechanism of splicing control, human T-STAR protein was able to repress splicing inclusion of the zebrafish Nrxn3 AS4 exon. Although Neurexin1-3 and Stxbp5l encode critical synaptic proteins, T-STAR null mice had no detectable spatial memory deficits, despite an almost complete absence of AS4 splicing repression in the hippocampus. Our work identifies T-STAR as an ancient and potent tissue-specific splicing regulator that uses a concentration-dependent mechanism to co-ordinately regulate regional splicing patterns of the Neurexin1-3 AS4 exons in the mouse brain. Show less

Continuous modes of renal replacement therapy (CRRT) are increasingly being utilized in the intensive care unit. The removal of cytokines and other inflammatory proteins during ultrafiltration may be responsible for some of the beneficial effects of CRRT. We used proteomic tools to identify proteins found in the ultrafiltrate from a patient with acute renal failure. Identification of these proteins could help elucidate the mechanism(s) of improved outcome with continuous renal replacement therapy. Protein was loaded on a reversed-phase C4 column and eluted with stepwise isocratic flows starting with 0%, 5%, 10%, 25%, and 50% of acetonitrile. Effluent was collected, pooled, desalted, and separated by two-dimensional gel electrophoresis (2DE). Reversed-phase separation improved the resolution and the number of spots seen on the gels. Protein spots were digested with trypsin and spotted onto MALDI plates. Proteins were identified by either peptide mass fingerprinting using a MALDI-TOF mass spectrometer or by peptide sequencing using a MALDI-TOF/TOF tandem mass spectrometer. From 196 spots cut, 47 were identified, representing multiple charge forms of 10 different proteins. Proteins identified were albumin, apolipoprotein A-IV, beta-2-microglobulin, lithostathine, mannose-binding lectin associated serine protease 2 associated protein, plasma retinol-binding protein, transferrin, transthyretin, vitamin D-binding protein and Zn alpha-2 glycoprotein. Continuous renal replacement therapy is frequently used in acutely ill patients with renal failure. Removal of proteins occurs during this process. The physiological significance of this protein removal is unclear. Identification of these proteins will lead to better understanding of the role of protein removal in continuous renal replacement therapy. Show less