Interleukin-10 (IL-10), first recognized for its ability to inhibit activation and effector function of T cells, monocytes, and macrophages, is a multifunctional cytokine with diverse effects on most hemopoietic cell types. The principal routine function of IL-10 appears to be to limit and ultimately terminate inflammatory responses. In addition to these activities, IL-10 regulates growth and/or differentiation of B cells, NK cells, cytotoxic and helper T cells, mast cells, granulocytes, dendritic cells, keratinocytes, and endothelial cells. IL-10 plays a key role in differentiation and function of a newly appreciated type of T cell, the T regulatory cell, which may figure prominently in control of immune responses and tolerance in vivo. Uniquely among hemopoietic cytokines, IL-10 has closely related homologs in several virus genomes, which testify to its crucial role in regulating immune and inflammatory responses. This review highlights findings that have advanced our understanding of IL-10 and its receptor, as well as its in vivo function in health and disease.

Interleukin-10 and the interleukin-10 receptor.

A large number of changes, distant from the site or sites of inflammation and involving many organ systems, may accompany inflammation. In 1930 interest was focused on these changes by the discovery of C-reactive protein (so named because it reacted with the pneumococcal C-polysaccharide) in the plasma of patients during the acute phase of pneumococcal pneumonia.1 Accordingly, these systemic changes have since been referred to as the acute-phase response,2 even though they accompany both acute and chronic inflammatory disorders. New acute-phase phenomena continue to be recognized, and the mechanisms mediating them are becoming better understood. This review summarizes much of . . .

Acute-Phase Proteins and Other Systemic Responses to Inflammation

Biologic basis for interleukin-1 in disease

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(05)71142-9.pdf

Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders.

More than any other cytokine family, the interleukin (IL)-1 family is closely linked to the innate immune response. This linkage became evident upon the discovery that the cytoplasmic domain of the IL-1 receptor type I is highly homologous to the cytoplasmic domains of all Toll-like receptors (TLRs). Thus, fundamental inflammatory responses such as the induction of cyclooxygenase type 2, increased expression of adhesion molecules, or synthesis of nitric oxide are indistinguishable responses of both IL-1 and TLR ligands. Both families nonspecifically affect antigen recognition and lymphocyte function. IL-1β is the most studied member of the IL-1 family because of its role in mediating autoinflammatory diseases. Although the TLR and IL-1 families evolved to assist in host defense against infection, unlike the TLR family, the IL-1 family also includes members that suppress inflammation, both specifically within the IL-1 family but also nonspecifically for TLR ligands and the innate immune response.

Immunological and Inflammatory Functions of the Interleukin-1 Family

The tyrosine kinase Wee1 is part of a key cellular sensing mechanism that signals completion of DNA replication, ensuring proper timing of entry into mitosis. Wee1 acts as an inhibitor of mitotic entry by phosphorylating cyclin-dependent kinase CDK1. Wee1 activity is mainly regulated at the protein level through its phosphorylation and subsequent degradation by the ubiquitin proteasome pathway. To facilitate identification of small molecules preventing Wee1 degradation, a homogeneous cell-based assay was developed using HeLa cells transiently transfected with a Wee1-luciferase fusion protein. To ensure ultra-high-throughput screening (uHTS) compatibility, the assay was scaled to a 1536-well plate format and cells were transfected in bulk and cryopreserved. This miniaturized homogeneous assay demonstrated robust performance, with a calculated Z′ factor of 0.65 +/− 0.05. The assay was screened against a publicly available library of approximately 218,000 compounds to identify Wee1 stabilizers. Nonselective, cytotoxic, and promiscuous compounds were rapidly triaged through the use of a similarly formatted counterscreen that measured stabilization of an N-cyclin B-luciferase fusion protein, as well as execution of viability assessment in the parental HeLa cell line. This screening campaign led to the discovery of 4 unrelated cell-permeable small molecules that showed selective Wee1-luciferase stabilization with micromolar potency. One of these compounds, SID-4243143 (ML118), was shown to inhibit cell cycle progression, underscoring the importance of Wee1 degradation to the cell cycle. This probe was found to be inactive in a whole-cell assay against its anti-target, cyclin B. In contrast, the current state-of-the-art probe, MG132, inhibits degradation of both Wee1 and cyclin B in the same assays. More importantly, flow-cytometry assays confirm that the probe is able to induce an increase in the G2/M population after cell treatment, without increasing the sub-G1 population, suggesting the probe is not toxic to cells. These results suggest that this uHTS approach is suitable for identifying selective chemical probes that prevent Wee1 degradation and generally applicable to discovering inhibitors of the ubiquitin proteasome pathway.

Small Molecule Inhibitors of Wee1 Degradation and Mitotic Entry

OBJECTIVE: To assess safety and tolerability of oral RPC1063 as single and multiple daily doses in healthy adults. BACKGROUND: RPC1063 is an oral, potent, selective sphingosine-1-phosphate receptor (S1P1R) modulator. Stimulation of the S1P1R results in sequestration of lymphocytes, which improves MS. DESIGN/METHODS: Randomized, double-blind, placebo-controlled, single and multiple ascending dose escalation, first-in-human study of RPC1063. Subjects were 88 healthy male and female subjects aged 18-55 years. The study included a single ascending dose (SAD) portion, multiple ascending dose portions for 7(MAD-7) and 28day(MAD-28), and a dose titration cohort. Cohorts included 8 subjects assigned to RPC1063 (6) or placebo (2). Doses were 0.3-3 mg(SAD), 0.3-2 mg(MAD-7), and 0.3-1.5 mg(MAD-28). RESULTS: Generally, RPC1063 treatment was well-tolerated. The most common AEs with RPC1063 were headache(9), somnolence(6), nausea(6), dizziness(5), fatigue(4), abdominal pain(3), and pruritus(3). No severe AEs were observed. AEs were generally similar in the placebo group. One MAD-28 subject receiving 1.5 mg had second degree, Mobitz-type-1-atrioventricular block on Day 1 of dosing and was discontinued; all other subjects completed the study. In the 3 mg SAD, 2 subjects experienced 2-second-sinus-pause during periods of sinus bradycardia, and 1 subject experienced intermittent bradycardia. These AEs resolved without medical intervention. A mild dose-dependent reduction in heart rate (HR) was observed with RPC1063. Dose titration appeared to attenuate reduction in HR. Two subjects in the 2 mg MAD-7 cohort had mild asymptomatic PFT abnormalities that resolved without medical intervention. Lymphocyte counts, used as a pharmacodynamic (PD) marker, decreased from baseline by 34% and 65% at doses of 0.3 and 1 mg, respectively. No apparent drug-related effects were observed for other clinical laboratory or ophthalmologic exams. CONCLUSIONS: RPC1063 was generally well tolerated, with a robust PD effect on lymphocyte counts seen at all doses. The emerging favorable safety and PD profile of RPC1063 support its continued development in patients with MS. Disclosure: Dr. Olson has received personal compensation for activities with Receptos as an employee. Dr. Olson holds stock and/or stock options in Receptos. Dr. Hartung has received personal compensation for activities with Receptos as an employee. Dr. Hartung holds stock and/or stock options in Receptos. Mr. Timony has received personal compensation for activities with Receptos, Inc. as an employee. Mr. Timony holds stock and/or stock options in Receptos, Inc. Dr. Peach has received personal compensation for activities with Receptos Inc. Dr. Peach holds stock and/or stock options from Receptos Inc. Dr. Boehm has received personal compensation for activities with Receptos Inc as an employee. Dr. Boehm holds stock and/or stock options from Receptos Inc. Dr. Rosen has received personal compensation for activities with Receptos Inc. as a consultant. Dr. Rosen holds stock and/or stock options in Receptos Inc. Dr. Smith has received personal compensation from Receptos. Dr. Smith holds stock and/or stock options in Receptos. Dr. Pan has received personal compensation for actvities with Receptos as a consultant. Ms. Brooks has received personal compensation for activities with Receptos Inc. as an employee. Ms. Brooks holds stock and/or stock options in Receptos Inc. Dr. Gujrathi has received personal compensation for activities with Receptos. Dr. Gujrathi holds stock and/or stock options in Receptos.

Safety and Tolerability of Orally Administered RPC1063, a Novel S1P1 Receptor Modulator, in Healthy Adult Volunteers, Results of a Phase 1 Study (P01.178)

Sa1221 Rpc1063, a Potent, Selective S1P1 Receptor Modulator, Is Active in a Therapeutic IBD Model and Exhibits Favorable PK/PD Properties in Healthy Volunteers

Oxidative stress has been implicated as an underlying inflammatory factor in several disease pathologies, including cancer, atherosclerosis, aging, and various neurodegenerative disorders. Phospholipids in particular are susceptible to oxidative damage, and it is thought that the cytosolic enzyme type II platelet-activating factor acetylhydrolase (PAFAH2) may facilitate turnover of oxidized phospholipids via hydrolysis of their oxidatively truncated acyl chains. In support of this theory, over-expression of PAFAH2 has been shown to reduce oxidative stress-induced cell death [1]. However, no selective inhibitors of PAFAH2 are known for investigation of PAFAH2 biology. We initiated a fluorescence polarization activity-based protein profiling (FluoPol-ABPP) HTS campaign to identify potential inhibitors of PAFAH2 (AIDs 492956 and 493030). The assay also served as a counterscreen for inhibitor discovery for the related enzyme, plasma PAFAH (pPAFAH; AIDs 463082, 463230).Interestingly, the triazole urea SID 7974398—a top lead in the lysophospholipase (LYPLA1) inhibitor screen from which we derived a dual inhibitor of LYPLA1/LYPLA2 (ML211) and inhibitor of ABHD11 (ML226)—was also a top hit in the PAFAH2 HTS assay. Given that triazole ureas were previously found to have tunable potency and selectivity, low cytotoxicity, and good activity in situ, we endeavored to derive a PAFAH2-selective probe from the triazole urea scaffold. The medchem optimized probe (ML225, SID 103913572) is highly potent against its target enzyme (IC50 = 3 nM), and is active in situ at sub-nanomolar concentrations. ML225 is at least 333-fold selective for all other serine hydrolases (~20) assessed by gel-based competitive activity-based protein profiling, and is selective for other PAFAH enzymes. ML225 inhibits PAFAH2 by carbamoylating the active site serine. The complete properties, characterization, and synthesis of ML225 are detailed in this Probe Report.

Optimization and characterization of a triazole urea inhibitor for platelet-activating factor acetylhydrolase type 2 (PAFAH2)

Sa1222 Results of a Safety and Tolerability Study of Rpc1063, a Novel Orally Administered Sphingosine-1-Phosphate Receptor 1 (S1p1r) Agonist, in Healthy Adult Volunteers

Hugh Rosen

Papers

Small Molecule Inhibitors of Wee1 Degradation and Mitotic Entry

Safety and Tolerability of Orally Administered RPC1063, a Novel S1P1 Receptor Modulator, in Healthy Adult Volunteers, Results of a Phase 1 Study (P01.178)

Sa1221 Rpc1063, a Potent, Selective S1P1 Receptor Modulator, Is Active in a Therapeutic IBD Model and Exhibits Favorable PK/PD Properties in Healthy Volunteers

Optimization and characterization of a triazole urea inhibitor for platelet-activating factor acetylhydrolase type 2 (PAFAH2)

Sa1222 Results of a Safety and Tolerability Study of Rpc1063, a Novel Orally Administered Sphingosine-1-Phosphate Receptor 1 (S1p1r) Agonist, in Healthy Adult Volunteers