Margot O'Toole

Inter-Regulation of Th17 Cytokines and the IL-36 Cytokines In Vitro and In Vivo: Implications in Psoriasis Pathogenesis

Accumulating evidence indicates that IL-1 family members and Th17 cytokines have a pathogenic role in psoriasis. We investigated the regulatory interactions of the IL-1-like IL-36 cytokine family and the Th17 cytokines in the context of skin inflammation. We observed increased gene expression of all three IL-36 cytokines in a Th17-dominant psoriasis-like animal model. The induction was downregulated by neutralizing IL-22. Expression of the IL-36s was also induced in cultured primary human keratinocytes (KC) by IL-17A and tumor necrosis factor (TNF)-α, and IL-22 synergized with IL-17A and TNF-α. Furthermore, the IL-36s directly induced their own expression and the production of proinflammatory mediators (TNF-α, IL-6, IL-8) in KC. These functions were markedly enhanced with the addition of IL-17A or TNF-α to the cultures. Similarly, IL-36α and IL-36β augmented IL-17A-mediated induction of antibacterial peptides. Finally, we show that the increased gene expression of IL-36 correlated with Th17 cytokines in the lesions of psoriatic patients. Our results indicate that the IL-36 cytokines are not only regulated by Th17 cytokines, but that they themselves can regulate the expression and enhance the function of Th17 cytokines. We propose that a feedback loop between the IL-36 and Th17 cytokines is involved in driving cytokine expression in psoriatic tissues.

Pathways Activated during Human Asthma Exacerbation as Revealed by Gene Expression Patterns in Blood

Background Asthma exacerbations remain a major unmet clinical need. The difficulty in obtaining airway tissue and bronchoalveolar lavage samples during exacerbations has greatly hampered study of naturally occurring exacerbations. This study was conducted to determine if mRNA profiling of peripheral blood mononuclear cells (PBMCs) could provide information on the systemic molecular pathways involved during asthma exacerbations. Methodology/Principal Findings Over the course of one year, gene expression levels during stable asthma, exacerbation, and two weeks after an exacerbation were compared using oligonucleotide arrays. For each of 118 subjects who experienced at least one asthma exacerbation, the gene expression patterns in a sample of peripheral blood mononuclear cells collected during an exacerbation episode were compared to patterns observed in multiple samples from the same subject collected during quiescent asthma. Analysis of covariance identified genes whose levels of expression changed during exacerbations and returned to quiescent levels by two weeks. Heterogeneity among visits in expression profiles was examined using K-means clustering. Three distinct exacerbation-associated gene expression signatures were identified. One signature indicated that, even among patients without symptoms of respiratory infection, genes of innate immunity were activated. Antigen-independent T cell activation mediated by IL15 was also indicated by this signature. A second signature revealed strong evidence of lymphocyte activation through antigen receptors and subsequent downstream events of adaptive immunity. The number of genes identified in the third signature was too few to draw conclusions on the mechanisms driving those exacerbations. Conclusions/Significance This study has shown that analysis of PBMCs reveals systemic changes accompanying asthma exacerbation and has laid the foundation for future comparative studies using PBMCs.

Intranasal Interleukin-12 is a Powerful Adjuvant for Protective Mucosal Immunity

The use of interleukin (IL)-12 as a new vaccine adjuvant for stimulating protective antiviral mucosal immunity has been examined. Mice were immunized intranasally (in) with an influenza vaccine consisting of soluble hemagglutinin (H1) and neuraminidase (N1) plus IL-12. This treatment resulted in elevated levels of lung and splenic interferon-gamma and IL-10 mRNA. Total and IgG2a anti-H1N1 antibody levels in serum were significantly elevated, as were total, IgG1, IgG2a, and secretory IgA antibody levels in bronchoalveolar lavage (BAL) fluids compared with animals receiving vaccine alone. Mice immunized in with vaccine and IL-12 also exhibited decreased weight loss and dramatically enhanced survival after lethal challenge with infectious influenza virus. Protection was dependent upon the presence of B cells and could be transferred to naive mice by inoculation of either serum or BAL fluid from IL-12-treated mice. These findings show for the first time that soluble IL-12 delivered in serves as a powerful respiratory adjuvant for protective antiviral immunity.

Anrukinzumab, an anti-interleukin 13 monoclonal antibody, in active UC: efficacy and safety from a phase IIa randomised multicentre study

Objective Interleukin 13 (IL-13) is thought to play a key role as an effector cytokine in UC. Anrukinzumab, a humanised antibody that inhibits human IL-13, was evaluated for the treatment of UC. Design In a multicentre, randomised, double-blind, placebo-controlled study, patients with active UC (Mayo score ≥4 and <10) were randomised to anrukinzumab 200, 400 or 600 mg or placebo. Patients received five intravenous administrations over 14 weeks. The primary endpoint was fold change from baseline in faecal calprotectin (FC) at Week 14. Secondary endpoints included safety, pharmacokinetics and IL-13 levels. Results The modified intention-to-treat population included 84 patients (21 patients/arm). Fold change of FC from baseline at Week 14 was not significantly different for any treatment groups compared with the placebo. The study had a high dropout rate, in part, related to lack of efficacy. The exploratory comparisons of each dose were not significantly different from placebo in terms of change from baseline in total Mayo score, clinical response, clinical remission and proportion of subjects with mucosal healing. An increase in serum total IL-13 (free and bound to anrukinzumab) was observed for all anrukinzumab groups but not with placebo. This suggests significant binding of anrukinzumab to IL-13. The safety profile was not different between the anrukinzumab and placebo groups. Conclusions A statistically significant therapeutic effect of anrukinzumab could not be demonstrated in patients with active UC in spite of binding of anrukinzumab to IL-13. Trial registration number ClinicalTrials.gov number NCT01284062.

Neonatal Administration of IL-12 Enhances the Protective Efficacy of Antiviral Vaccines

Neonates are highly susceptible to infectious agents and are known to display polarized expression of Th2-like cytokines and Abs. This neonatal immune bias has important implications for the development of vaccine strategies, particularly against viral infections. We now report that coadministration of IL-12 and an influenza subunit vaccine at birth enhances the protective efficacy of antiviral vaccination. Immunization and treatment with IL-12 within 24 h of birth resulted in elevated expression of IFN-γ, IL-10, and IL-15 mRNA in the spleens of newborn mice compared with animals exposed to vaccine only. In addition, these animals showed dramatic increases in IFN-γ-, IL-2-, and IL-4-secreting cells, and in IgG2a Ab levels upon adult challenge compared with mice primed with vaccine alone. Most importantly, animals vaccinated and simultaneously treated with IL-12 at birth displayed enhanced survival after lethal challenge with infectious influenza virus as adults compared with infected animals that had been primed with vaccine alone. This augmented protection required B cells and could be transferred to naive mice by immune serum. Collectively, these results provide evidence that administration of IL-12 to neonates induces a Th1-like response in newborns and elicits protective antiviral immune memory.

Matrix metalloproteinase-12 is a therapeutic target for asthma in children and young adults.

BACKGROUND Matrix metalloproteinase (MMP)-12-mediated pathologic degradation of the extracellular matrix and the subsequent repair cycles influence the airway changes in patients with asthma and chronic obstructive pulmonary disease (COPD). The common serine variant at codon 357 of the MMP12 gene (rs652438) is associated with clinical manifestations consistent with more aggressive matrix degradation in other tissues. OBJECTIVE We sought to explore the hypothesis that MMP12 represents a novel therapeutic target in asthma. METHODS The role of the rs652438 variant on clinical phenotype was explored in young asthmatic patients and patients with COPD. Candidate MMP-12 inhibitors were identified on the basis of potency and selectivity against a panel of other MMPs. The role of MMP-12-specific inhibition was tested in vitro, as well as in animal models of allergic airway inflammation. RESULTS The odds ratio for having greater asthma severity was 2.00 (95% CI, 1.24-3.24; P = .004) when comparing asthmatic patients with at least 1 copy of the serine variant with those with none. The carrier frequency for the variant increased in line with asthma treatment step (P = .000). The presence of the variant nearly doubled the odds in favor of asthmatic exacerbations (odds ratio, 1.90; 95% CI, 1.19-3.04; P = .008) over the previous 6 months. The serine variant was also associated with increased disease severity in patients with COPD (P = .016). Prior administration of an MMP-12-specific inhibitor attenuated the early airway response and completely blocked the late airway response with subsequent Ascaris suum challenge in sheep. CONCLUSION Studies on human participants with asthma and COPD show that the risk MMP12 gene variant is associated with disease severity. In allergen-sensitized sheep pharmacologic inhibition of MMP12 downregulates both early and late airway responses in response to allergic stimuli.

Mapping similarities in mTOR pathway perturbations in mouse lupus nephritis models and human lupus nephritis

IntroductionTreatment with sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, has been shown to be efficacious in the MRL/lpr and NZB × NZW F1 mouse models of lupus nephritis, indicating a critical role for the mTOR pathway in both models. This type of demonstration of efficacy in animal models is usually a pre-requisite for advancement into clinical development. However, efficacy in an animal model often has not translated to the desired activity in the clinic. Therefore, a more profound understanding of the mechanistic similarities and differences between various animal models and human diseases is highly desirable.MethodsTranscriptional profiling was performed on kidneys from mice with lupus nephritis; from mice who had efficacious drug treatment; and from mice before they developed nephritis. Analysis of variance with false discovery rate adjusted to p < 0.05 and an average fold change of two or more was used to identify transcripts significantly associated with disease and response to therapy. Pathway analyses (using various bioinformatics tools) were carried out to understand the basis for drug efficacy in the mouse model. The relevance in human lupus of the pathways identified in the mouse model was explored using information from several databases derived from the published literature.ResultsWe identified a set of nephritis-associated genes in mouse kidney. Expression of the majority of these returned to asymptomatic levels on sirolimus treatment, confirming the correlation between expression levels and symptoms of nephritis. Network analysis showed that many of these nephritis genes are known to interact with the mTOR pathway. This led us to ask what human diseases are linked to the mTOR pathway. We constructed the mTOR pathway interactome consisting of proteins that interact with members of the mTOR pathway and identified a strong association between mTOR pathway genes and genes reported in the literature as being involved in human lupus.ConclusionsOur findings implicate the mTOR pathway as a critical contributor to human lupus. This broad pathway-based approach to understanding the similarities in, and differences between, animal models and human diseases may have broader utility.

The balance of expression of PTPN22 splice forms is significantly different in rheumatoid arthritis patients compared with controls

BackgroundThe R620W variant in protein tyrosine phosphatase non-receptor 22 (PTPN22) is associated with rheumatoid arthritis (RA). The PTPN22 gene has alternatively spliced transcripts and at least two of the splice forms have been confirmed to encode different PTPN22 (LYP) proteins, but detailed information regarding expression of these is lacking, especially with regard to autoimmune diseases.MethodsWe have investigated the mRNA expression of known PTPN22 splice forms with TaqMan real-time PCR in relation to ZNF592 as an endogenous reference in peripheral blood cells from three independent cohorts with RA patients (n = 139) and controls (n = 111) of Caucasian origin. Polymorphisms in the PTPN22 locus (25 SNPs) and phenotypic data (gender, disease activity, ACPA and RF status) were used for analysis. Additionally, we addressed possible effects of methotrexate treatment on PTPN22 expression.ResultsWe found consistent differences in the expression of the PTPN22 splice forms in unstimulated peripheral blood mononuclear cells between RA patients and normal controls. This difference was more pronounced when comparing the ratio of splice forms and was not affected by methotrexate treatment.ConclusionsOur data show that RA patients and healthy controls have a shift in balance of expression of splice forms derived from the PTPN22 gene. This balance seems not to be caused by treatment and may be of importance during immune response due to great structural differences in the encoded PTPN22 proteins.

Correlation of pharmacodynamic activity, pharmacokinetics, and anti-product antibody responses to anti-IL-21R antibody therapeutics following IV administration to cynomolgus monkeys.

BackgroundAnti-IL-21R antibodies are potential therapeutics for the treatment of autoimmune diseases. This study evaluated correlations between the pharmacodynamic (PD) activity, pharmacokinetics, and anti-product antibody responses of human anti-IL-21R antibodies Ab-01 and Ab-02 following IV administration to cynomolgus monkeys.MethodsThe PD assay was based on the ability of recombinant human IL-21 (rhuIL-21) to induce expression of the IL-2RA gene in cynomolgus monkey whole blood samples ex vivo. Monkeys screened for responsiveness to rhuIL-21 stimulation using the PD assay, were given a single 10 mg/kg IV dosage of Ab-01, Ab-02, or a control antibody (3/group), and blood samples were evaluated for PD activity (inhibition of IL-2RA expression) for up to 148 days. Anti-IL-21R antibody concentrations and anti-product antibody responses were measured in serum using immunoassays and flow cytometry.ResultsFollowing IV administration of Ab-01 and Ab-02 to cynomolgus monkeys, PD activity was observed as early as 5 minutes (first time point sampled). This PD activity had good correlation with the serum concentrations and anti-product antibody responses throughout the study. The mean terminal half-life (t1/2) was ~10.6 and 2.3 days for Ab-01 and Ab-02, respectively. PD activity was lost at ~5-13 weeks for Ab-01 and at ~2 weeks for Ab-02, when serum concentrations were relatively low. The estimated minimum concentrations needed to maintain PD activity were ~4-6 nM for Ab-01 and ~2.5 nM for Ab-02, and were consistent with the respective KD values for binding to human IL-21R. For Ab-01, there was noticeable inter-animal variability in t1/2 values (~6-14 days) and the resulting PD profiles, which correlated with the onset of anti-product antibody formation. While all three Ab-01-dosed animals were positive for anti-Ab-01 antibodies, only one monkey (with the shortest t1/2 and the earliest loss of PD activity) had evidence of neutralizing anti-Ab-01 antibodies. All three Ab-02-dosed monkeys developed neutralizing anti-Ab-02 antibodies.ConclusionsFor anti-IL-21R antibodies Ab-01 and Ab-02, there was good correlation between PD activity and PK profiles following IV administration to cynomolgus monkeys. Compared with Ab-01, Ab-02 was eliminated markedly faster from the circulation, which correlated with a shorter duration of PD activity.

Dose-Dependent and Schedule-Dependent Effects of Interleukin-12 on Antigen-Specific CD8 Responses

Interleukin-12 (IL-12) has been shown to play a central role in the innate and acquired immune responses. Its activities include enhancement of natural killer (NK) and cytotoxic T lymphocyte (CTL) activity and promotion of CD4 Th1 cell development. It has also been shown to provide potent activity as a vaccine adjuvant in generating antibody and T cell responses. We have investigated the efficacy of IL-12 protein in promoting CD8 T cell responses when it is used as an adjuvant for immunization. Studies using, as antigen, cDNA from an autologous antigen (P1A) as well as studies of responses to vaccinia virus-delivered self (gp100) and non-self (beta-galactosidase) antigens show that the dose and schedule of IL-12 administration can significantly affect adjuvant activity, leading to enhancement or suppression of antigen-specific responses.