Project description:A persistent and non-resolving inflammatory response to accumulating Aβ peptide species is a cardinal feature in the development of Alzheimer's disease (AD). In response to accumulating Aβ peptide species, microglia, the innate immune cells of the brain, generate a toxic inflammatory response that accelerates synaptic and neuronal injury. Many pro-inflammatory signaling pathways are linked to progression of neurodegeneration. However, endogenous anti-inflammatory pathways capable of suppressing Aβ-induced inflammation represent a relatively unexplored area. Here we hypothesized that signaling through the prostaglandin-E2 (PGE2) EP4 receptor potently suppresses microglial inflammatory responses to Aβ42 peptides. In cultured microglial cells, EP4 stimulation attenuated levels of Aβ42-induced inflammatory factors and potentiated phagocytosis of Aβ42. Microarray analysis was performed and demonstrated that EP4 stimulation broadly opposed Aβ42-driven gene expression changes in microglia, with enrichment for targets of IRF1, IRF7, and NF-κB transcription factors.
Project description:The EP4 receptor is known to mediate the protective effect of prostaglandin (PG) E2 in the gastrointestinal tract; however, the exact role of epithelial EP4 in intestinal pathophysiology remains unknown. We investigated the role of epithelial EP4 in maintaining colonic homeostasis by characterizing the intestinal epithelial cell-specific EP4 knockout (EP4 cKO) mice. We found a significant enrichment of genes involved in apoptosis-related pathways in the EP4 cKO colons. Moreover, inflammation-associated pathways were highly enriched and revealed more than half of the top 20 pathways related to immune response.
Project description:A persistent and non-resolving inflammatory response to accumulating A? peptide species is a cardinal feature in the development of Alzheimer's disease (AD). In response to accumulating A? peptide species, microglia, the innate immune cells of the brain, generate a toxic inflammatory response that accelerates synaptic and neuronal injury. Many pro-inflammatory signaling pathways are linked to progression of neurodegeneration. However, endogenous anti-inflammatory pathways capable of suppressing A?-induced inflammation represent a relatively unexplored area. Here we hypothesized that signaling through the prostaglandin-E2 (PGE2) EP4 receptor potently suppresses microglial inflammatory responses to A?42 peptides. In cultured microglial cells, EP4 stimulation attenuated levels of A?42-induced inflammatory factors and potentiated phagocytosis of A?42. Microarray analysis was performed and demonstrated that EP4 stimulation broadly opposed A?42-driven gene expression changes in microglia, with enrichment for targets of IRF1, IRF7, and NF-?B transcription factors. Primary microglia were isolated from the brains of postnatal day 7 C57BL/6J mouse pups using the Neural Tissue Dissociation Kit (P), MACS Separation Columns (LS), and magnetic CD11b Microbeads from Miltenyi Biotec (Auburn, CA). Microglia from three separate litters of pups were maintained as three independent biological replicates for each treatment. After being cultured for three days, microglia were treated with oligomeric A?42 (10uM) and/or the specific EP4 agonist AE1-329 (100nM) for 6 hours. These 4 treatment conditions (A? + AE1, A? alone, AE1 alone, and vehicle alone) and 3 independent biological replicates per treatment gave us 12 total samples. After 6 hours of treatment, RNA was isolated from the microglia for microarray analysis.
Project description:Changes of genome-wide mRNA transcription levels of human ciliary smooth muscle (hCSM) cells were determined by treating hCSM cells in culture with 200 nM of either an prostaglandin E2 receptor subtype EP2 or subtype EP4 selective agonist for 6 hours in comparison to untreated controls. This was followed by competitive hybridization of fluorescent Cy3 or Cy5 labeled cRNA probes derived from the treated versus untreated control total RNA samples onto an Agilent Human Whole Genome Expression oligonucleotide microarray. Log 2 (LN) of the intra-slide ratios (RATIO, PRE_VALUE) of treated versus untreated samples was reported as VALUE in the sample files. Keywords: prostaglandin E2 receptor agonists, subtype EP2, subtype EP4, hCSM
Project description:While the role of prostaglandin E2 (PGE2) in promoting malignant progression is well-established, how to optimally block the activity of PGE2 signaling remains to be demonstrated. Clinical trials with prostaglandin pathway targeted agents have shown activity but without sufficient significance or dose-limiting toxicities that have prevented approval. PGE2 signals through four receptors (EP1-4) to modulate tumor progression. EP2 and EP4 signaling exacerbates tumor pathology and is immunosuppressive through potentiating cAMP production. EP1 and EP3 signaling has the opposite effect through increasing IP3 and decreasing cAMP. Using available small molecule antagonists of single EP receptors, the COX-2 inhibitor celecoxib, or a novel dual EP2/EP4 antagonist generated in this investigation, we tested which approach to block PGE2 signaling optimally restored immunologic activity in mouse and human immune cells and antitumor activity in syngeneic, spontaneous and xenograft tumor models. We found that dual antagonism of EP2 and EP4 together significantly enhanced the activation of PGE2-suppressed mouse and human monocytes and CD8+ T cells in vitro as compared to single EP antagonists. CD8+ T cell activation was dampened by single EP1 and EP3 antagonists. Dual EP2/EP4 PGE2 receptor antagonists increased TME lymphocyte infiltration and significantly reduced disease burden in multiple tumor models, including in the adenomatous polyposis coli (APC)min+/- spontaneous colorectal tumor model, compared to celecoxib. These results support a hypothesis that redundancy of EP2 and EP4 receptor signaling necessitates a therapeutic strategy of dual blockade of EP2 and EP4. Here we describe TPST-1495, a first-in-class orally available small molecule dual EP2/EP4 antagonist.
Project description:Recognition of foreign antigens by B cell receptor (BCR) on mature B cells leads to their clonal expansion, which is critically important for the effective host defence of the organism. However, excessive antigenic responses or reaction of B cells against bodyâs own components frequently lead to diverse immune diseases, such as B-cell lymphoma or autoimmunity, that often affect humans. Identification of genes that restrain uncontrolled proliferation of B cells is therefore an important goal towards understanding the origin of such diseases. Here we identify Ptger4 as a negative feedback regulator of B-cell proliferation in response to BCR triggering, and show that its encoded EP4 receptor is a principal molecule conveying the growth-suppressive effect of prostaglandin E2 (PGE2). In controlled in vitro assays, Ptger4-/- B cells showed augmented proliferative response and increased expression of activating genes upon BCR stimulation. Stable knock-down of Ptger4 in B-cell lymphoma markedly accelerated tumour spread in mice, while Ptger4 overexpression yielded significant protection. Lack of Ptger4 rendered mouse B cells completely resistant to proliferation arrest signalled by PGE2, and we find by transcriptional profiling that intrinsic activity of Ptger4 and PGE2-EP4 signalling target a similar set of activating genes. We further show that Ptger4 inhibits mouse B-cell activation in vivo and find it significantly downregulated in human B-cell lymphoma. Our results demonstrate that Ptger4 functions in B cells as a candidate tumour suppressor whose activity is regulated by the presence of PGE2 in the microenvironment. These findings suggest that targeting EP4 receptor for prostaglandin may present a novel strategy for treatment of B-cell diseases. Keywords: time course, cell type comparison, compound treatment design, microarray experiment record B cells were extracted from spleen of Ptger4+/+ and Ptger4-/- mice, and incubated in vitro for the indicated period with or without anti-IgM (Fab')2 antibody fragments and co-treated with or without PGE2. Total RNA was extracted, amplified, labelled with Cy3 or Cy5, and hybridized to mouse 24k oligo-arrays using a dye-swap strategy.
Project description:To examine the effects of prostaglandin E2/EP4 signaling on bovine CD4+ T cells, CD4+ T cells were isolated from bovine peripheral blood mononuclear cells. Isolated CD4+ T cells were cultured with anti-bovine CD3 and anti-bovine CD28 monoclonal antibodies. Following 18 hours of incubation, the cultures were incubated with EP4 agonist or DMSO, a vehicle control for 4 hours. After incubation, the cells were collected and microarray analysis was performed.