The landscape of new therapeutic opportunities for IBD.

This chapter presents an overview of the emerging strategies to address the unmet needs in the management of inflammatory bowel diseases (IBD). IBD poses significant challenges, as over half of patients experience disease progression despite interventions, leading to irreversible complications, and a substantial proportion do not respond to existing therapies, such as biologics. To overcome these limitations, we describe a diverse array of novel therapeutic approaches.

Challenges in IBD Research 2024: Preclinical Human IBD Mechanisms.

Preclinical human inflammatory bowel disease (IBD) mechanisms is one of 5 focus areas of the Challenges in IBD Research 2024 document, which also includes environmental triggers, novel technologies, precision medicine, and pragmatic clinical research. Herein, we provide a comprehensive overview of current gaps in inflammatory bowel diseases research that relate to preclinical research and deliver actionable approaches to address them with a focus on how these gaps can lead to advancements in IBD interception, remission, and restoration. The document is the result of multidisciplinary input from scientists, clinicians, patients, and funders and represents a valuable resource for patient-centric research prioritization.

Profiling drugs for rheumatoid arthritis that inhibit synovial fibroblast activation.

Activation of synovial fibroblasts (SFs) contributes to rheumatoid arthritis (RA) by damaging synovial membranes and generating inflammatory cytokines that recruit immune cells to the joint. In this paper we profile cytokine secretion by primary human SFs from healthy tissues and from donors with RA and show that SF activation by TNF, IL-1α, and polyinosinic-polycytidylic acid (Poly(I:C)) cause secretion of multiple cytokines found at high levels in RA synovial fluids. We used interaction multiple linear regression to quantify therapeutic and countertherapeutic drug effects across activators and donors and found that the ability of drugs to block SF activation was strongly dependent on the identity of the activating cytokine.

BI 1002494, a Novel Potent and Selective Oral Spleen Tyrosine Kinase Inhibitor, Displays Differential Potency in Human Basophils and B Cells.

BI 1002494 [(R)-4-{(R)-1-[7-(3,4,5-trimethoxy-phenyl)-[1,6]napthyridin-5-yloxy]-ethyl}pyrrolidin-2-one] is a novel, potent, and selective spleen tyrosine kinase (SYK) inhibitor with sustained plasma exposure after oral administration in rats, which qualifies this molecule as a good in vitro and in vivo tool compound. BI 1002494 exhibits higher potency in inhibiting high-affinity IgE receptor-mediated mast cell and basophil degranulation (IC50 = 115 nM) compared with B-cell receptor-mediated activation of B cells (IC50 = 810 nM). This may be explained by lower kinase potency when the physiologic ligand B-cell linker was used, suggesting that SYK inhibitors may exhibit differential potency depending on the cell type and the respective signal transduction ligand.

A High-Throughput Genetic Complementation Assay in Yeast Cells Identified Selective Inhibitors of Sphingosine Kinase 1 Not Found Using a Cell-Free Enzyme Assay.

Sphingosine kinase 1 (SphK1) is a lipid kinase that phosphorylates sphingosine to produce the bioactive sphingolipid, sphingosine-1-phosphate (S1P), and therefore represents a potential drug target for a variety of pathological processes such as fibrosis, inflammation, and cancer. We developed two assays compatible with high-throughput screening to identify small-molecule inhibitors of SphK1: a purified component enzyme assay and a genetic complementation assay in yeast cells. The biochemical enzyme assay measures the phosphorylation of sphingosine-fluorescein to S1P-fluorescein by recombinant human full-length SphK1 using an immobilized metal affinity for phosphochemicals (IMAP) time-resolved fluorescence resonance energy transfer format.

Comprehensive profiling analysis of actively resorbing osteoclasts identifies critical signaling pathways regulated by bone substrate.

As the only cells capable of efficiently resorbing bone, osteoclasts are central mediators of both normal bone remodeling and pathologies associates with excessive bone resorption. However, despite the clear evidence of interplay between osteoclasts and the bone surface in vivo, the role of the bone substrate in regulating osteoclast differentiation and activation at a molecular level has not been fully defined. Here, we present the first comprehensive expression profiles of osteoclasts differentiated on authentic resorbable bone substrates.

Creating and analyzing pathway and protein interaction compendia for modelling signal transduction networks.

Background: Understanding the information-processing capabilities of signal transduction networks, how those networks are disrupted in disease, and rationally designing therapies to manipulate diseased states require systematic and accurate reconstruction of network topology. Data on networks central to human physiology, such as the inflammatory signalling networks analyzed here, are found in a multiplicity of on-line resources of pathway and interactome databases (Cancer CellMap, GeneGo, KEGG, NCI-Pathway Interactome Database (NCI-PID), PANTHER, Reactome, I2D, and STRING). We sought to determine whether these databases contain overlapping information and whether they can be used to construct high reliability prior knowledge networks for subsequent modeling of experimental data.

Hemostasis in oral surgery.

The control of hemorrhage is a key component for the clinician to understand before performing oral surgical procedures. Hemostasis may be obtained primarily by local hemostatic measures. If hemostasis is not achieved with this modality, various hemostatic agents exist, which may be used as adjuncts to obtain hemostasis.

A technique for long term decompression of large mandibular cysts.

Decompression is a conservative treatment that has frequently been used in the treatment of large odontogenic cysts. Techniques described in the recent literature have involved only fixation of a stent to soft tissue. In the present investigators' experiences, this technique has a high failure rate because of the dislodgement of the stent, due to tearing of the sutures over the course of a long-span treatment period.

Hemostatic agents.

Hemostasis is an integral and very important aspect of surgical practice. As a rule, most bleeding from dental surgery can be controlled by pressure. When the application of pressure does not yield satisfactory results, or where more effective hemostasis is required, hemostatic agents are used.

Cloning and expression of human mitogen-activated protein kinase kinase 7gamma1.

Mitogen-activated protein kinase kinase 7 (MKK7) is a direct activator of the mitogen-activated protein kinase family member c-Jun N-terminal kinase (JNK). MKK7 activates JNK via phosphorylation of a threonine and tyrosine residue in a Thr-Pro-Tyr motif within kinase subdomain VIII. To date at least six different isoforms of murine MKK7 have been identified.

IL-1 receptor-associated kinase modulates host responsiveness to endotoxin.

Endotoxin triggers many of the inflammatory, hemodynamic, and hematological derangements of Gram-negative septic shock. Recent genetic studies in mice have identified the Toll-like receptor 4 as the transmembrane endotoxin signal transducer. The IL-1 intracellular signaling pathway has been implicated in Toll-like receptor signal transduction.

Stimulation of NFkappa B activity by multiple signaling pathways requires PAK1.

The p21-activated kinase (PAK1) is a serine-threonine protein kinase that is activated by binding to the Rho family small G proteins Rac and Cdc42hs. Both Rac and Cdc42hs have been shown to regulate the activity of the transcription factor NFkappaB. Here we show that expression of active Ras, Raf-1, or Rac1 in fibroblasts stimulates NFkappaB in a PAK1-dependent manner and that expression of active PAK1 can stimulate NFkappaB on its own.

Normal hematopoiesis and inflammatory responses despite discrete signaling defects in Galpha15 knockout mice.

Galpha15 activates phospholipase Cbeta in response to the greatest variety of agonist-stimulated heptahelical receptors among the four Gq class G-protein alpha subunits expressed in mammals. Galpha15 is primarily expressed in hematopoietic cells in fetal and adult mice. We disrupted the Galpha15 gene by homologous recombination in embryonic stem cells to identify its biological functions.

Prolonged activation of ERK2 by epidermal growth factor and other growth factors requires a functional insulin-like growth factor 1 receptor.

We have investigated the activation of ERK2, a serine/threonine kinase necessary for transmission of mitogenic signals, in cells derived from mouse embryos homozygous for a null mutation of the insulin-like growth factor (IGF)-1R gene (R- cells) and from wild-type littermates (W cells), respectively. Stimulation of quiescent W cells with IGF-1, epidermal growth factor (EGF), or with a combination growth factors induced both a maximal transient and a prolonged activation of ERK2, whereas platelet-derived growth factor or a combination of platelet-derived growth factor and EGF resulted only in transient activation of ERK2. In contrast, stimulation of R cells with IGF-1, EGF, or combinations of growth factors resulted in a transient and submaximal activation of ERK2.

Lipopolysaccharide-induced tumor necrosis factor-alpha promoter activity is inhibitor of nuclear factor-kappaB kinase-dependent.

The adverse effects of lipopolysaccharide (LPS) are primarily mediated by tumor necrosis factor-alpha (TNF-alpha). TNF-alpha production by LPS-stimulated macrophages is regulated both transcriptionally and post-transcriptionally. Transcriptional regulation of the TNF-alpha gene is dependent on nuclear factor-kappaB (NF-kappaB).

TNF receptor-associated factor-3 signaling mediates activation of p38 and Jun N-terminal kinase, cytokine secretion, and Ig production following ligation of CD40 on human B cells.

CD40 engagement induces a variety of functional outcomes following association with adaptor molecules of the TNF receptor-associated factor (TRAF) family. Whereas TRAF2, -5, and -6 initiate NF-kappaB activation, the outcomes of TRAF3-initiated signaling are less characterized. To delineate CD40-induced TRAF3-dependent events, Ramos B cells stably transfected with a dominant negative TRAF3 were stimulated with membranes expressing recombinant CD154/CD40 ligand.

Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) is required for lipopolysaccharide stimulation of tumor necrosis factor alpha (TNF-alpha) translation: glucocorticoids inhibit TNF-alpha translation by blocking JNK/SAPK.

The adverse effects of lipopolysaccharide (LPS) are mediated primarily by tumor necrosis factor alpha (TNF-alpha). TNF-alpha production by LPS-stimulated macrophages is regulated at the levels of both transcription and translation. It has previously been shown that several mitogen-activated protein kinases (MAPKs) are activated in response to LPS.

Dissociation of mitogenesis and transforming activity by C-terminal truncation of the insulin-like growth factor-I receptor.

We have investigated the mitogenic and transforming ability of an IGF-I receptor with a 108-amino-acid C-terminal truncation in R- cells, which are 3T3-like cells derived from mouse embryos in which the IGF-I receptor genes have been disrupted by targeted homologous recombination. R- cells stably transfected with expression plasmids encoding either a wild-type or a truncated human IGF-I receptor were capable of growing in serum-free medium supplemented solely with IGF-I. This response was observed over a wide range of receptor levels.

An E2F binding sequence negatively regulates the response of the insulin-like growth factor 1 (IGF-I) promoter to simian virus 40T antigen and to serum.

The promoter of the Insulin-like growth factor I (IGF-I) gene is activated by the Simian Virus 40 large T antigen (SVLT), and one of the elements responding to SVLT activation has been localized to a short 124 bp immediately upstream of the first initiation of transcription site. This short promoter contains an E2F binding site, that, in gel shifts, binds a protein complex, but only when the promoter activity is reduced or absent. A mutation in the E2F binding site deregulates the activity of the promoter, which becomes active even in those conditions in which the wild type promoter is inactive.

IGF-1 receptor levels and the proliferation of young and senescent human fibroblasts.

We have investigated the role of the IGF-1 receptor in the proliferation of young and senescent human diploid fibroblasts. Using WI-38 cells, we have established the following: 1) both young and senescent cells have IGF-1 receptors, which can be autophosphorylated by IGF-1, the intensity of the autophosphorylation being roughly the same in both types of cells; 2) the levels of IGF-1 receptor mRNA are also similar in young and senescent cells; 3) both young and senescent cells have an absolute requirement for the IGF-1 receptor in order to be stimulated by either serum or SV40, respectively; 4) despite these similarities, young cells respond to IGF-1 (in combination with other growth factors) with DNA synthesis and mitosis, and senescent cells do not. We conclude that, although the IGF-1 receptor is still needed by senescent cells for a growth response to SV40, it is not, by itself, the determinant of senescence, at least in WI-38 cells.