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Background Preclinical data from a murine model of acute colitis suggest that dual blockade of interleukin(IL)-23 and TNFα more effectively prevented the development of colonic inflammation than each monotherapy. Guselkumab(GUS), an IL-23p19 subunit antagonist, is being studied in inflammatory bowel disease. Golimumab(GOL), a TNFα antagonist, is approved for ulcerative colitis(UC). The objective of this study was to evaluate the efficacy and safety of combination induction therapy with GUS+GOL vs GUS or GOL alone in adults with moderately-to-severely active UC. Methods 214 patients(pts) naïve to TNFα antagonists and refractory or intolerant to conventional therapy(ie, immunomodulators and/or corticosteroids) were randomly assigned to receive GUS 200mg intravenous(IV) at weeks(wks) 0, 4, and 8(n=71); GOL 200mg subcutaneous(SC) at wk0 then 100mg SC at wks2, 6, and 10(n=72); or combination with GUS 200mg IV+GOL 200mg SC at wk0, GOL 100mg SC at wks2, 6, and 10, and GUS 200mg IV at wks4 and 8(n=71). The primary endpoint was clinical response at wk12; the major secondary endpoint was clinical remission at wk12. Other key endpoints were clinical remission based on the modified Mayo score (mMayo), symptomatic remission, endoscopic improvement, endoscopic normalization, histologic remission, composite histologic-endoscopic endpoints, and biomarker outcomes. Results Baseline disease characteristics were similar among groups(Table 1), however a greater proportion of pts in both monotherapy groups had pancolitis vs the combination group. A greater proportion of pts who received combination therapy achieved clinical response at wk12(83.1%) vs GUS(74.6%) or GOL(61.1%)(Table 2). Similarly, the proportion of pts who achieved clinical remission in the combination group(36.6%) was greater than that of monotherapy groups(21.1% and 22.2%, respectively). Clinical remission by mMayo score, endoscopic improvement, histologic remission, both histologic remission and endoscopic improvement, and biomarker normalization (calprotectin, CRP) rates at wk12 were also greater in the combination group vs GUS or GOL. Percentages of pts with endoscopic normalization and both histologic remission and endoscopic normalization were nearly double with combination therapy vs either monotherapy. Adverse event(AE), serious AE, and infection rates were comparable among treatment groups. One pt receiving combination therapy experienced a serious infection of influenza and sepsis. No deaths, malignancies, or TB cases were reported through wk12. Conclusion Combination induction treatment with GUS+GOL more effectively induced clinical response, clinical remission, and endoscopic improvement at wk12 than either monotherapy alone. AE rates were comparable among the treatment groups.

Background Despite advances in the treatment of inflammatory bowel diseases (IBD), fewer than, 40% of patients reach clinical remission, suggesting that improved response rates may require targeting of multiple pathogenic pathways through combination therapy. However, the rational selection of combination therapies based on patient and pre-clinical data remains a significant challenge. Methods Here, we used Crohn’s disease (CD) patient-derived molecular networks as a platform for bridging pre-clinical animal models of combination therapy to human disease. Intestinal transcriptional signatures of anti-TNF, anti-IL-23 or combination treatments were generated from the anti-CD40 agonistic antibody murine colitis model and the murine genes mapped to their human orthologues. Humanized gene signatures were intersected with human disease networks to generate treatment subnetworks and enrichment analyses performed. Results The anti-TNF subnetwork was enriched in genes expressed in myeloid cells, chemokine signaling and NFkB signaling, while the anti-IL-23 subnetwork was enriched in genes expressed in the intestinal epithelium, IL-17 signaling, and cell adhesion. The intersection of these two therapeutic gene signature subnetworks was significantly enriched in IBD GWAS loci genes and human CD inflammatory gene signatures, suggesting that the molecular mechanisms reflected in the pre-clinical model faithfully captures aspects of the human disease. Simultaneous inhibition of these two pathways could result in enhanced efficacy through targeting shared inflammatory pathways and complementary biology in myeloid and epithelial cells to reduce colitis. To test this hypothesis, mice were treated with varying doses of anti-IL-23, anti-TNF, or the combination of both. A synergistic response to combination therapy was observed both in reduction of systemic weight loss and inhibition of local colonic tissue inflammation by histopathology. A set of genes uniquely significantly modulated by the combination therapy compared to either monotherapy was mapped to our human IBD network. Upregulated gene networks in the combination therapy enriched in stromal cells, epithelial mesenchymal transition and extracellular matrix pathways, and adhesion pathways while downregulated gene networks were enriched in IBD disease signatures, M1 macrophages, neutrophils and IFN-γ signaling. Conclusion These results provide a novel, data-driven approach to predict effective combination therapies for inflammatory diseases and suggest that anti-TNF and anti-IL-23 combination therapy may drive more patients into deep remission through impacts on both shared and unique molecular pathways involved in IBD pathogenesis.

Introduction Aged PS19 mice (MAPT P301S), a mouse model of tauopathy and neurodegeneration, display reduced NREM and REM sleep starting around 8-9 months before death around 12 months. Here, we tested the acute effect of a dual orexin receptor antagonist (DORA-12) on sleep in 11 mice (5 male, 6 female) at 10.3±1.8 months. Methods Two consecutive 24-hour recordings (12/12hr L:D cycle) were scored semi-automatically for non-REM sleep, REM sleep, and wake in mice implanted with EEG/EMG. Mice were treated with either vehicle (day 1) or 100mg/kg of DORA-12 (day 2) by oral gavage at both ZT0 and ZT9. Results After the first dose at ZT0, both latency to the first NREM sleep episode (paired t-test p=0.002) and to the first REM sleep episode (paired t-test p=0.005) was significantly shorter with DORA-12 (NREM: 20.8±17.8 min.; REM: 23.5±21.2 min.) compared to vehicle (NREM: 49.2±22.3 min.; REM: 127.0±93.3 min.). There was no difference in NREM or REM sleep latency observed after the second dose at ZT9. DORA-12 treatment increased NREM duration across the 24hr period (DORA-12: 664±52 min.; Veh: 601±54 min., paired t-test p=0.007) and also after the 2nd dose (DORA-12: 311±65 min.; Veh: 263±84 min., paired t-test p=0.009). DORA-12 treatment also increased REM duration across 24hrs (DORA-12: 61±30 min.; Veh: 48±29 min., paired t-test p=0.014) but not after the 2nd dose alone (DORA-12: 22±14 min.; Veh: 20±15 min., paired t-test p=0.388). Notably in both vehicle and DORA-12 conditions, we observed apparent dream enactment behavior including mastication, paw grasp, and fore limb extension during REM in 3 of 11 PS19 mice (all male), not typically observed in younger PS19 or age-matched non-transgenic mice, suggestive of a possible REM behavior disorder (RBD) phenotype. Wake-like behaviors occurred during theta-dominant EEG but with an EMG amplitude >4SD the preceding NREM sleep baseline for at least > 1sec. Conclusion In aged PS19 mice, DORA-12 was found to decrease the latency to NREM and REM after the first dose while also increasing NREM and REM duration across the entire 24hr recording period. We also capture a heretofore undescribed RBD-like phenotype in aged PS19 tauopathy mice. Support Merck MISP

Plague, a primarily flea-borne disease caused by Yersinia pestis, is characterized by rapidly spreading epizootics separated by periods of quiescence. Little is known about how and where Y. pestis persists between epizootics. It is commonly proposed, however, that Y. pestis is maintained during interepizootic periods in enzootic cycles involving flea vectors and relatively resistant host populations. According to this model, while susceptible individuals serve as infectious sources for feeding fleas and subsequently die of infection, resistant hosts survive infection, develop antibodies to the plague bacterium, and continue to provide bloodmeals to infected fleas. For Y. pestis to persist under this scenario, fleas must remain infected after feeding on hosts carrying antibodies to Y. pestis. Studies of other vector-borne pathogens suggest that host immunity may negatively impact pathogen survival in the vector. Here, we report infection rates and bacterial loads for fleas (both Xenopsylla cheopis (Rothschild) and Oropsylla montana (Baker)) that consumed an infectious bloodmeal and subsequently fed on an immunized or age-matched naive mouse. We demonstrate that neither the proportion of infected fleas nor the bacterial loads in infected fleas were significantly lower within 3 d of feeding on immunized versus naive mice. Our findings thus provide support for one assumption underlying the enzootic host model of interepizootic maintenance of Y. pestis.

Background The Centers for Disease Control and Prevention (CDC) and others reported that methicillin-resistant S. aureus (MRSA) are significant causes of serious human infections, including pulmonary illnesses. We investigated the role played by superantigens in lung-associated lethal illness in rabbits. Methods A rabbit model was established to investigate the potential role played by superantigens, staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin C (SEC), and toxic shock syndrome toxin-1 (TSST-1). Rabbits received intrabronchial community-associated (CA) MRSA strains USA200 (TSST-1(+)), MW2 (SEC(+)), c99-529 (SEB(+)), or purified superantigens. Some rabbits were preimmunized against superantigens or treated with soluble high-affinity T cell receptors (Vβ-TCR) to neutralize SEB and then challenged intrabronchially with CA-MRSA or superantigens. Results Rabbits challenged with CA-MRSA or superantigens developed fatal, pulmonary illnesses. Animals preimmunized against purified superantigens, or treated passively with Vβ-TCRs and then challenged with CA-MRSA or superantigens, survived. Lung histological analysis indicated that nonimmune animals developed lesions consistent with necrotizing pneumonia after challenge with CA-MRSA or purified superantigens. Superantigen-immune animals or animals treated with soluble Vβ-TCRs did not develop pulmonary lesions. Conclusions Superantigens contribute to lethal pulmonary illnesses due to CA-MRSA; preexisting immunity to superantigens prevents lethality. Administration of high-affinity Vβ-TCR with specificity for SEB to nonimmune animals protects from lethal pulmonary illness resulting from SEB(+) CA-MRSA and SEB.

The role of deer mice and other species of Peromyscus as enzootic reservoirs for plague remains controversial. In this study, we evaluated early-phase vector efficiency of Aetheca wagneri Baker, a common flea species infesting deer mice, to determine the likelihood that Y. pestis could be spread mouse to mouse by this species. We showed that A. wagneri could transmit plague bacteria to laboratory mice as early as 3 d postinfection (p.i.), but transmission efficiency was quite low (1.03%; 95% CI: 0.19–3.34%) 1–4 d p.i. compared with that for the established plague vector Oropsylla montana Baker (10.63%; 95% CI: 4.18–25.91). Using this early-phase transmission efficiency estimate, we determined through parameterization of a simple predictive model that at least 68 A. wagneri per deer mouse would be required to support levels of transmission adequate for enzootic maintenance. Because deer mice typically harbor fewer than three A. wagneri per host, our data do not support the notion of an independent...

Yersinia pestis, the etiological agent of plague, is transmitted by multiple flea species. Previous studies have reported wide variability in transmission efficiency among competent vectors. However, it is unclear to what extent such variation is explained by methodological differences among studies. To optimize an artificial feeding system where fleas are infected with controlled numbers of Y. pestis under standardized laboratory conditions that could be used to systematically compare vector efficiency, we sought to test the effect of host bloodmeal source on 1) the flea’s ability to remain infected with Y. pestis and 2) bacterial loads in fleas. Here, we demonstrate that both prevalence of infection with a virulent strain of Y. pestis (CO96–3188) and bacterial loads in rock squirrel fleas (Oropsylla montana) are affected by host-associated blood factors. The generality of this observation was confirmed by repeating the study using the rat flea (Xenopsylla cheopis) and a commonly used avirulent ...