Immune Sensing of Synthetic, Bacterial, and Protozoan RNA by Toll-like Receptor 8 Requires Coordinated Processing by RNase T2 and RNase 2.

Human toll-like receptor 8 (TLR8) activation induces a potent T helper-1 (Th1) cell response critical for defense against intracellular pathogens, including protozoa. The receptor harbors two distinct binding sites, uridine and di- and/or trinucleotides, but the RNases upstream of TLR8 remain poorly characterized. We identified two endolysosomal endoribonucleases, RNase T2 and RNase 2, that act synergistically to release uridine from oligoribonucleotides. RNase T2 cleaves preferentially before, and RNase 2 after, uridines. Live bacteria, P. falciparum-infected red blood cells, purified pathogen RNA, and synthetic oligoribonucleotides all required RNase 2 and T2 processing to activate TLR8. Uridine supplementation restored RNA recognition in RNASE2-/- or RNASET2-/- but not RNASE2-/-RNASET2-/- cells. Primary immune cells from RNase T2-hypomorphic patients lacked a response to bacterial RNA but responded robustly to small-molecule TLR8 ligands. Our data identify an essential function of RNase T2 and RNase 2 upstream of TLR8 and provide insight into TLR8 activation.

Sequence-specific activation of the DNA sensor cGAS by Y-form DNA structures as found in primary HIV-1 cDNA.

Cytosolic DNA that emerges during infection with a retrovirus or DNA virus triggers antiviral type I interferon responses. So far, only double-stranded DNA (dsDNA) over 40 base pairs (bp) in length has been considered immunostimulatory. Here we found that unpaired DNA nucleotides flanking short base-paired DNA stretches, as in stem-loop structures of single-stranded DNA (ssDNA) derived from human immunodeficiency virus type 1 (HIV-1), activated the type I interferon-inducing DNA sensor cGAS in a sequence-dependent manner. DNA structures containing unpaired guanosines flanking short (12- to 20-bp) dsDNA (Y-form DNA) were highly stimulatory and specifically enhanced the enzymatic activity of cGAS. Furthermore, we found that primary HIV-1 reverse transcripts represented the predominant viral cytosolic DNA species during early infection of macrophages and that these ssDNAs were highly immunostimulatory. Collectively, our study identifies unpaired guanosines in Y-form DNA as a highly active, minimal cGAS recognition motif that enables detection of HIV-1 ssDNA.

A Conserved Histidine in the RNA Sensor RIG-I Controls Immune Tolerance to N1-2'O-Methylated Self RNA.

The cytosolic helicase retinoic acid-inducible gene-I (RIG-I) initiates immune responses to most RNA viruses by detecting viral 5'-triphosphorylated RNA (pppRNA). Although endogenous mRNA is also 5'-triphosphorylated, backbone modifications and the 5'-ppp-linked methylguanosine ((m7)G) cap prevent immunorecognition. Here we show that the methylation status of endogenous capped mRNA at the 5'-terminal nucleotide (N1) was crucial to prevent RIG-I activation. Moreover, we identified a single conserved amino acid (H830) in the RIG-I RNA binding pocket as the mediator of steric exclusion of N1-2'O-methylated RNA. H830A alteration (RIG-I(H830A)) restored binding of N1-2'O-methylated pppRNA. Consequently, endogenous mRNA activated the RIG-I(H830A) mutant but not wild-type RIG-I. Similarly, knockdown of the endogenous N1-2'O-methyltransferase led to considerable RIG-I stimulation in the absence of exogenous stimuli. Studies involving yellow-fever-virus-encoded 2'O-methyltransferase and RIG-I(H830A) revealed that viruses exploit this mechanism to escape RIG-I. Our data reveal a new role for cap N1-2'O-methylation in RIG-I tolerance of self-RNA.

A novel serum extracellular vesicle protein signature to monitor glioblastoma tumor progression.

Detection of tumor progression in patients with glioblastoma remains a major challenge. Extracellular vesicles (EVs) are potential biomarkers and can be detected in the blood of patients with glioblastoma. In our study, we evaluated the potential of serum-derived EVs from glioblastoma patients to serve as biomarker for tumor progression. EVs from serum of glioblastoma patients and healthy volunteers were separated by size exclusion chromatography and ultracentrifugation. EV markers were defined by using a proximity-extension assay and bead-based flow cytometry. Tumor progression was defined according to modified RANO criteria. EVs from the serum of glioblastoma patients (n = 67) showed an upregulation of CD29, CD44, CD81, CD146, C1QA and histone H3 as compared to serum EVs from healthy volunteers (P value range: <.0001 to .08). For two independent cohorts of glioblastoma patients, we noted upregulation of C1QA, CD44 and histone H3 upon tumor progression, but not in patients with stable disease. In a multivariable logistic regression analysis, a combination of CD29, CD44, CD81, C1QA and histone H3 correlated with RANO-defined tumor progression with an AUC of 0.76. Measurement of CD29, CD44, CD81, C1QA and histone H3 in serum-derived EVs of glioblastoma patients, along with standard MRI assessment, has the potential to improve detection of true tumor progression and thus could be a useful biomarker for clinical decision making.

Induction of Interferon-Stimulated Genes Correlates with Reduced Growth of Influenza A Virus in Lungs after RIG-I Agonist Treatment of Ferrets.

Intracellular RIG-I receptors represent key innate sensors of RNA virus infection, and RIG-I activation results in the induction of hundreds of host effector genes, including interferon-stimulated genes (ISGs). Synthetic RNA agonists targeting RIG-I have shown promise as antivirals against a broad spectrum of viruses, including influenza A virus (IAV), in both in vitro and mouse models of infection. Herein, we demonstrate that treatment of a ferret airway epithelial (FRL) cell line with a RIG-I agonist rapidly and potently induced expression of a broad range of ISGs and resulted in potent inhibition of growth of different IAV strains. In ferrets, a single intravenous injection of RIG-I agonist was associated with upregulated ISG expression in peripheral blood mononuclear cells and lung tissue, but not in nasal tissues. In a ferret model of viral contact transmission, a single treatment of recipient animals 24 h prior to cohousing with IAV-infected donors did not reduce virus transmission and shedding but did result in reduced lung virus titers 6 days after treatment. A single treatment of the IAV-infected donor animals also resulted in reduced virus titers in the lungs 2 days later. Thus, a single intravenous treatment with RIG-I agonist prior to infection or to ferrets with an established IAV infection can reduce virus growth in the lungs. These findings support further development of RIG-I agonists as effective antiviral treatments to limit the impact of IAV infections, particularly in reducing virus replication in the lower airways. IMPORTANCE RIG-I agonists have shown potential as broad-spectrum antivirals in vitro and in mouse models of infection. However, their antiviral potential has not been reported in outbred animals such as ferrets, which are widely regarded as the gold standard small animal model for human IAV infections. Herein, we demonstrate that RIG-I agonist treatment of a ferret airway cell line resulted in ISG induction and inhibition of a broad range of human influenza viruses. A single intravenous treatment of ferrets also resulted in systemic induction of ISGs, including in lung tissue, and when delivered to animals prior to IAV exposure or to animals with established IAV infection treatment resulted in reduced virus replication in the lungs. These data demonstrate the effectiveness of single RIG-I treatment against IAV in the ferret model and highlight the importance of future studies to optimize treatment regimens and delivery routes to maximize their ability to ameliorate IAV infections.

Retinoic Acid-Inducible Gene I Activation Inhibits Human Respiratory Syncytial Virus Replication in Mammalian Cells and in Mouse and Ferret Models of Infection.

Infections caused by human respiratory syncytial virus (RSV) are associated with substantial rates of morbidity and mortality. Treatment options are limited, and there is urgent need for the development of efficient antivirals. Pattern recognition receptors such as the cytoplasmic helicase retinoic acid-inducible gene (RIG) I can be activated by viral nucleic acids, leading to activation of interferon-stimulated genes and generation of an "antiviral state." In the current study, we activated RIG-I with synthetic RNA agonists (3pRNA) to induce resistance to RSV infection in vitro and in vivo. In vitro, pretreatment of human, mouse, and ferret airway cell lines with RIG-I agonist before RSV exposure inhibited virus infection and replication. Moreover, a single intravenous injection of 3pRNA 1 day before RSV infection resulted in potent inhibition of virus replication in the lungs of mice and ferrets, but not in nasal tissues. These studies provide evidence that RIG-I agonists represent a promising antiviral drug for RSV prophylaxis.

Elevated baseline C-reactive protein levels predict poor progression-free survival in sporadic vestibular schwannoma.

BACKGROUND: Recent investigations showed emerging evidence of the role of inflammation in the growth of sporadic vestibular schwannoma (VS). The present retrospective study investigated the impact of systemic inflammation on tumor progression using serum C-reactive protein (CRP) levels in a series of 87 surgically treated sporadic VS patients. METHODS: The optimal cut-off value for CRP was defined as 3.14 mg/dl according to the receiver operating characteristic curve (AUC: 0.70, 95% CI 0.47-0.92). Patient cohort was dichotomized into normal (n = 66; < 3.14 mg/dl) and high baseline (n = 21; ≥ 3.14 mg/dl) CRP groups. RESULTS: No significant differences in age, sex, comorbidities influencing the systemic inflammatory state, Karnofsky performance status (KPS), tumor size, extent of resection, or MIB-1 index were identified between the two groups defined by the baseline CRP levels. Univariable analysis demonstrated that a high CRP level (≥ 3.14 mg/dl) is significantly associated with a shortened progression-free survival (PFS) (hazard ratio (HR): 6.05, 95% CI 1.15-31.95, p = 0.03). Multivariable Cox regression analysis considering age, extent of resection, KPS, tumor size, and baseline CRP confirmed that an elevated CRP level (≥ 3.14 mg/dl) is an independent predictor of shortened PFS (HR: 7.20, 95% CI 1.08-48.14, p = 0.04). CONCLUSIONS: The baseline CRP level thus serves as an independent predictor of PFS. Further investigations of the role of inflammation and tumor inflammatory microenvironment in the prediction of prognosis in sporadic VS are needed.

MGMT promoter methylation analysis for allocating combined CCNU/TMZ chemotherapy: Lessons learned from the CeTeG/NOA-09 trial.

The CeTeG/NOA-09 trial showed a survival benefit for combined CCNU/TMZ therapy in MGMT-promoter-methylated glioblastoma patients (quantitative methylation-specific PCR [qMSP] ratio > 2). Here, we report on the prognostic value of the MGMT promoter methylation ratio determined by qMSP and evaluate the concordance of MGMT methylation results obtained by qMSP, pyrosequencing (PSQ) or DNA methylation arrays (MGMT-STP27). A potential association of qMSP ratio with survival was analyzed in the CeTeG/NOA-09 trial population (n = 129; log-rank tests, Cox regression analyses). The concordance of MGMT methylation assays (qMSP, PSQ and MGMT-STP27) was evaluated in 76 screened patients. Patients with tumors of qMSP ratio > 4 showed superior survival compared to those with ratios 2-4 (P = .0251, log-rank test). In multivariate analysis, the qMSP ratio was not prognostic across the study cohort (hazard ratio [HR] = 0.88; 95% CI: 0.72-1.08). With different cutoffs for qMSP ratio (4, 9, 12 or 25), the CCNU/TMZ benefit tended to be larger in subgroups with lower ratios (eg, for cutoff 9: HR 0.32 for lower subgroup, 0.73 for higher subgroup). The concordance rates with qMSP were 94.4% (PSQ) and 90.2% (MGMT-STP27). Discordant results were restricted to tumors with qMSP ratios ≤4 and PSQ mean methylation rate ≤25%. Despite a shorter survival in MGMT-promoter-methylated patients with lower methylation according to qMSP, these patients had a benefit from combined CCNU/TMZ therapy, which even tended to be stronger than in patients with higher methylation rates. With acceptable concordance rates, decisions on CCNU/TMZ therapy may also be based on PSQ or MGMT-STP27.

Extracellular Vesicle Separation Techniques Impact Results from Human Blood Samples: Considerations for Diagnostic Applications.

Extracellular vesicles (EVs) are reminiscent of their cell of origin and thus represent a valuable source of biomarkers. However, for EVs to be used as biomarkers in clinical practice, simple, comparable, and reproducible analytical methods must be applied. Although progress is being made in EV separation methods for human biofluids, the implementation of EV assays for clinical diagnosis and common guidelines are still lacking. We conducted a comprehensive analysis of established EV separation techniques from human serum and plasma, including ultracentrifugation and size exclusion chromatography (SEC), followed by concentration using (a) ultracentrifugation, (b) ultrafiltration, or (c) precipitation, and immunoaffinity isolation. We analyzed the size, number, protein, and miRNA content of the obtained EVs and assessed the functional delivery of EV cargo. Our results demonstrate that all methods led to an adequate yield of small EVs. While no significant difference in miRNA content was observed for the different separation methods, ultracentrifugation was best for subsequent flow cytometry analysis. Immunoaffinity isolation is not suitable for subsequent protein analyses. SEC + ultracentrifugation showed the best functional delivery of EV cargo. In summary, combining SEC with ultracentrifugation gives the highest yield of pure and functional EVs and allows reliable analysis of both protein and miRNA contents. We propose this combination as the preferred EV isolation method for biomarker studies from human serum or plasma.

Lomustine-temozolomide combination therapy versus standard temozolomide therapy in patients with newly diagnosed glioblastoma with methylated MGMT promoter (CeTeG/NOA-09): a randomised, open-label, phase 3 trial.

BACKGROUND: There is an urgent need for more effective therapies for glioblastoma. Data from a previous unrandomised phase 2 trial suggested that lomustine-temozolomide plus radiotherapy might be superior to temozolomide chemoradiotherapy in newly diagnosed glioblastoma with methylation of the MGMT promoter. In the CeTeG/NOA-09 trial, we aimed to further investigate the effect of lomustine-temozolomide therapy in the setting of a randomised phase 3 trial. METHODS: In this open-label, randomised, phase 3 trial, we enrolled patients from 17 German university hospitals who were aged 18-70 years, with newly diagnosed glioblastoma with methylated MGMT promoter, and a Karnofsky Performance Score of 70% and higher. Patients were randomly assigned (1:1) with a predefined SAS-generated randomisation list to standard temozolomide chemoradiotherapy (75 mg/m2 per day concomitant to radiotherapy [59-60 Gy] followed by six courses of temozolomide 150-200 mg/m2 per day on the first 5 days of the 4-week course) or to up to six courses of lomustine (100 mg/m2 on day 1) plus temozolomide (100-200 mg/m2 per day on days 2-6 of the 6-week course) in addition to radiotherapy (59-60 Gy). Because of the different schedules, patients and physicians were not masked to treatment groups. The primary endpoint was overall survival in the modified intention-to-treat population, comprising all randomly assigned patients who started their allocated chemotherapy. The prespecified test for overall survival differences was a log-rank test stratified for centre and recursive partitioning analysis class. The trial is registered with ClinicalTrials.gov, number NCT01149109. FINDINGS: Between June 17, 2011, and April 8, 2014, 141 patients were randomly assigned to the treatment groups; 129 patients (63 in the temozolomide and 66 in the lomustine-temozolomide group) constituted the modified intention-to-treat population. Median overall survival was improved from 31·4 months (95% CI 27·7-47·1) with temozolomide to 48·1 months (32·6 months-not assessable) with lomustine-temozolomide (hazard ratio [HR] 0·60, 95% CI 0·35-1·03; p=0·0492 for log-rank analysis). A significant overall survival difference between groups was also found in a secondary analysis of the intention-to-treat population (n=141, HR 0·60, 95% CI 0·35-1·03; p=0·0432 for log-rank analysis). Adverse events of grade 3 or higher were observed in 32 (51%) of 63 patients in the temozolomide group and 39 (59%) of 66 patients in the lomustine-temozolomide group. There were no treatment-related deaths. INTERPRETATION: Our results suggest that lomustine-temozolomide chemotherapy might improve survival compared with temozolomide standard therapy in patients with newly diagnosed glioblastoma with methylated MGMT promoter. The findings should be interpreted with caution, owing to the small size of the trial. FUNDING: German Federal Ministry of Education and Research.

Aflibercept for choroidal neovascularizations secondary to pseudoxanthoma elasticum: a prospective study.

PURPOSE: To evaluate the use of 2 mg intravitreal aflibercept for treatment of choroidal neovascularization (CNV) secondary to angioid streaks in patients with pseudoxanthoma elasticum (PXE). METHODS: In this 12-month prospective, open-label, uncontrolled, non-randomized interventional clinical trial, 15 PXE patients with CNV (mean age: 53 years, range 22-65) received one initial intravitreal injection of 2 mg aflibercept. Further injections were based on CNV activity at monthly examinations. The primary endpoint was change of best corrected visual acuity (BCVA) after 12 months. Secondary outcomes were change of central retinal thickness (CRT), leakage from CNV, retinal sensitivity, and vision-related quality of life. RESULTS: BCVA improved from 75.0 ± 10.8 (± SD, Snellen equivalent 20/32) to 79.3 ± 7.3 ETDRS letters (20/32) at final visit (p = 0.083). CRT decreased from 317 ± 81 to 279 ± 51 µm (p = 0.004). Retinal sensitivity on microperimetry changed from 17.8 ± 4.5 to 18.5 ± 4.3 dB (p = 0.103) and vision-related quality of life from a VQF-25 score of 80.7 ± 10.4 to 83.5 ± 14.5 (p = 0.554). The mean number of injections was 6.7 ± 2.6, and 5 participants had persistent or reactivated CNV activity at final visit. The observed adverse events were comparable with studies on aflibercept for other indications. CONCLUSION: The results of this study indicate that intravitreal aflibercept is a treatment option for CNV secondary to PXE.

Analysis of Serum miRNA in Glioblastoma Patients: CD44-Based Enrichment of Extracellular Vesicles Enhances Specificity for the Prognostic Signature.

Glioblastoma is a devastating disease, for which biomarkers allowing a prediction of prognosis are urgently needed. microRNAs have been described as potentially valuable biomarkers in cancer. Here, we studied a panel of microRNAs in extracellular vesicles (EVs) from the serum of glioblastoma patients and evaluated their correlation with the prognosis of these patients. The levels of 15 microRNAs in EVs that were separated by size-exclusion chromatography were studied by quantitative real-time PCR, followed by CD44 immunoprecipitation (SEC + CD44), and compared with those from the total serum of glioblastoma patients (n = 55) and healthy volunteers (n = 10). Compared to total serum, we found evidence for the enrichment of miR-21-3p and miR-106a-5p and, conversely, lower levels of miR-15b-3p, in SEC + CD44 EVs. miR-15b-3p and miR-21-3p were upregulated in glioblastoma patients compared to healthy subjects. A significant correlation with survival of the patients was found for levels of miR-15b-3p in total serum and miR-15b-3p, miR-21-3p, miR-106a-5p, and miR-328-3p in SEC + CD44 EVs. Combining miR-15b-3p in serum or miR-106a-5p in SEC + CD44 EVs with any one of the other three microRNAs in SEC + CD44 EVs allowed for a prognostic stratification of glioblastoma patients. We have thus identified four microRNAs in glioblastoma patients whose levels, in combination, can predict the prognosis for these patients.

Health-related quality of life and neurocognitive functioning with lomustine-temozolomide versus temozolomide in patients with newly diagnosed, MGMT-methylated glioblastoma (CeTeG/NOA-09): a randomised, multicentre, open-label, phase 3 trial.

BACKGROUND: The CeTeG/NOA-09 trial showed significantly longer overall survival with combined lomustine-temozolomide therapy compared with standard temozolomide for patients with glioblastoma with methylated MGMT promoter. The trial also aimed to investigate the effect of lomustine-temozolomide therapy on health-related quality of life (HRQOL) and neurocognitive function, which we report here. METHODS: In this randomised, multicentre, open-label, phase 3 trial, newly diagnosed, chemoradiotherapy-naive patients with MGMT-methylated glioblastoma, aged 18-70 years, with a Karnofsky performance score of 70% or higher, were recruited and enrolled at 17 university hospitals in Germany. Patients received standard radiotherapy (60 Gy) and were randomly assigned (1:1, stratified by centre by allocating complete blocks of six to a centre, without masking) to either six 6-week courses of oral combined lomustine (100 mg/m2 on day 1) plus temozolomide (100-200 mg/m2 on days 2-6) or standard oral temozolomide (75 mg/m2 daily during radiotherapy plus six 4-week courses of temozolomide [150-200 mg/m2] on days 1-5, every 4 weeks). The primary endpoint was overall survival. HRQOL, assessed using the European Organisation for Research and Treatment of Cancer (EORTC) quality of life questionnaire core-30 and the EORTC brain cancer module (BN20); and neurocognitive function, assessed using the Mini Mental State Examination (MMSE), plus a neurocognitive test battery (NOA-07), including Trail Making Test A and B (TMT-A and B), working memory tests, and tests for lexical (Controlled Oral Word Association [COWA]) and semantic verbal fluency, were secondary endpoints analysed in the modified intention-to-treat population (mITT; all randomly assigned patients who received at least one dose of study chemotherapy). We used linear mixed-model analyses to investigate differences between treatment groups regarding HRQOL (clinically relevant ≥10 points) and MMSE scores (clinically relevant ≥3 points). The trial is registered with ClinicalTrials.gov, NCT01149109. FINDINGS: Between June 17, 2011 and April 8, 2014, 141 patients were randomly assigned and 129 patients began treatment and were included in the mITT population (63 in the temozolomide and 66 in the lomustine-temozolomide group). Median follow-up for HRQOL (the item global health) was 19·4 months (IQR 7·8-38·6), for MMSE was 15·3 months (4·1-29·6), and for COWA was 11·0 months (0-27·5). We found no significant impairment regarding any item of HRQOL in the lomustine-temozolomide group (difference between the groups for global health 0·30 [95% CI -0·23 to 0·83]; p=0·26). Differences in MMSE were in favour of the temozolomide group (difference -0·11 [95% CI -0·19 to -0·03]; p=0·0058) but were not clinically relevant (1·76/30 points over 4 years). We found no significant difference between the groups in any subtest of the neurocognitive test battery (difference for COWA 0·04 [95% CI -0·01 to 0·09]; p=0·14). INTERPRETATION: The absence of systematic and clinically relevant changes in HRQOL and neurocognitive function combined with the survival benefit of lomustine-temozolomide versus temozolomide alone suggests that a long-term net clinical benefit exists for patients with newly diagnosed glioblastoma with methylation of the MGMT promoter and supports the use of lomustine-temozolomide as a treatment option for these patients. FUNDING: German Federal Ministry of Education and Research.

Direct RIG-I activation in human NK cells induces TRAIL-dependent cytotoxicity toward autologous melanoma cells.

Activation of the innate immune receptor retinoic acid-inducible gene I (RIG-I) by its specific ligand 5'-triphosphate RNA (3pRNA) triggers anti-tumor immunity, which is dependent on natural killer (NK) cell activation and cytokine induction. However, to date, RIG-I expression and the functional consequences of RIG-I activation in NK cells have not been examined. Here, we show for the first time the expression of RIG-I in human NK cells and their activation upon RIG-I ligand (3pRNA) transfection. 3pRNA-activated NK cells killed melanoma cells more efficiently than NK cells activated by type I interferon. Stimulation of RIG-I in NK cells specifically increased the surface expression of membrane-bound TNF-related apoptosis-inducing ligand (TRAIL) on NK cells, while activated NK cell receptors were not affected. RIG-I-induced membrane-bound TRAIL initiated death-receptor-pathway-mediated apoptosis not only in allogeneic but also in autologous human leukocyte antigen (HLA) class I-positive and HLA class I-negative melanoma cells. These results identify the direct activation of RIG-I in NK cells as a novel mechanism for how RIG-I can trigger enhanced NK cell killing of tumor cells, underscoring the potential of RIG-I activation for tumor immunotherapy.

Effect of transcutaneous vagus nerve stimulation on muscle activity in the gastrointestinal tract (transVaGa): a prospective clinical trial.

PURPOSE: Postoperative ileus (POI) is a common complication after abdominal surgery. Invasive stimulation of the cervical vagus nerve is known to reduce inflammatory response and ameliorated POI after surgery in a mouse model. However, the transcutaneous vagus nerve stimulation (tVNS) is a possible non-invasive approach. In this clinical study, we aimed to investigate the effect of tVNS on the activation of the stomach muscle in humans. METHODS: Patients requiring open laparotomy were screened for this prospective proof of concept clinical study. After open laparotomy, muscle activity of the stomach was measured by a free running electromyography (EMG) before and during tVNS on the ear. Frequency and amplitude of compound gastric action potentials were the electrophysiological parameters we assessed to reveal the changes in electro motor gastric activity. Gastrin levels as a surrogate marker for vagus nerve activation was analyzed before, 1 and 3 h after tVNS. RESULTS: Fourteen patients were included, no severe adverse events and no medical device related adverse events occurred. tVNS led to significant reduction of action potential frequency and significant elevation of action potential amplitude in the stomach compared to control. Gastrin levels were significantly elevated 3 h after tVNS compared to levels before tVNS. CONCLUSION: Application of tVNS is a safe and feasible procedure during surgical intervention. Our results provide evidence that tVNS activates efferent visceral vagal fibers. Therefore, this low risk and easy to perform method could be useful to prevent postoperative ileus. CLINICAL TRIAL REGISTER NUMBER: DRKS00013340.

Recognition of 5' triphosphate by RIG-I helicase requires short blunt double-stranded RNA as contained in panhandle of negative-strand virus.

Antiviral immunity is triggered by immunorecognition of viral nucleic acids. The cytosolic helicase RIG-I is a key sensor of viral infections and is activated by RNA containing a triphosphate at the 5' end. The exact structure of RNA activating RIG-I remains controversial. Here, we established a chemical approach for 5' triphosphate oligoribonucleotide synthesis and found that synthetic single-stranded 5' triphosphate oligoribonucleotides were unable to bind and activate RIG-I. Conversely, the addition of the synthetic complementary strand resulted in optimal binding and activation of RIG-I. Short double-strand conformation with base pairing of the nucleoside carrying the 5' triphosphate was required. RIG-I activation was impaired by a 3' overhang at the 5' triphosphate end. These results define the structure of RNA for full RIG-I activation and explain how RIG-I detects negative-strand RNA viruses that lack long double-stranded RNA but do contain blunt short double-stranded 5' triphosphate RNA in the panhandle region of their single-stranded genome.

Cutting Edge: The RIG-I Ligand 3pRNA Potently Improves CTL Cross-Priming and Facilitates Antiviral Vaccination.

Protective immunity against intracellular pathogens involves the induction of robust CTL responses. Vaccination with protein Ags establishes such responses only when combined with immune-stimulatory adjuvants. In this study, we compared different adjuvants and identified triphosphate RNA (3pRNA) as especially effective at inducing CTL responses. 3pRNA sensing required IPS-1/MAVS signaling and induced type I IFN in plasmacytoid dendritic cells and macrophages, with the latter being more important for the adjuvant effect. Type I IFN acted on CD11c(+) cells, especially on CD8α(+) Batf3-dependent dendritic cells. Vaccination with OVA in combination with 3pRNA protected mice from a subsequent OVA-encoding adenovirus infection in a CD8(+) cell-dependent manner and more efficiently than other adjuvants. In summary, 3pRNA is a superior adjuvant for CTL activation and might be useful to facilitate antiviral immunization strategies.

RIG-I Activation Protects and Rescues from Lethal Influenza Virus Infection and Bacterial Superinfection.

Influenza A virus infection causes substantial morbidity and mortality in seasonal epidemic outbreaks, and more efficient treatments are urgently needed. Innate immune sensing of viral nucleic acids stimulates antiviral immunity, including cell-autonomous antiviral defense mechanisms that restrict viral replication. RNA oligonucleotide ligands that potently activate the cytoplasmic helicase retinoic-acid-inducible gene I (RIG-I) are promising candidates for the development of new antiviral therapies. Here, we demonstrate in an Mx1-expressing mouse model of influenza A virus infection that a single intravenous injection of low-dose RIG-I ligand 5'-triphosphate RNA (3pRNA) completely protected mice from a lethal challenge with influenza A virus for at least 7 days. Furthermore, systemic administration of 3pRNA rescued mice with pre-established fulminant influenza infection and prevented the fatal effects of a streptococcal superinfection. Type I interferon, but not interferon-λ, was required for the therapeutic effect. Our results suggest that the use of RIG-I activating oligonucleotide ligands has the clinical potential to confine influenza epidemics when a strain-specific vaccine is not yet available and to reduce lethality of influenza in severely infected patients.

Who is a 'healthy subject'?-consensus results on pivotal eligibility criteria for clinical trials.

INTRODUCTION/METHODS: A discussion forum was hosted by the German not-for-profit Association for Applied Human Pharmacology (AGAH e.V.) to critically review key eligibility criteria and stopping rules for clinical trials with healthy subjects, enrolling stakeholders from the pharmaceutical industry, contract research organisations, academia, ethics committees and competent authority. RESULTS: Pivotal eligibility criteria were defined for trials with new investigational medicinal products (IMPs) or with clinically established IMPs. In general, a pulse rate ranging between 50 and 90 beats/min is recommended for first-in-human (FIH) trials, while wider ranges seem acceptable for trials with clinically established IMPs, provided there are no indications of thyroid dysfunction. Hepatic laboratory parameters not to exceed the upper limit of normal (ULN) comprise ALT (alanine aminotransferase) and AST (aspartate aminotransferase) in FIH trials, whereas slight elevations (10% above ULN) seem acceptable in trials with clinically established IMPs without known hepatotoxicity. A normal renal function is required for any clinical trial in healthy subjects. A risk-adapted approach for stopping rules was adopted. Stopping rules for an individual subject are one adverse event of severe intensity or one serious adverse event. In case of a severe adverse event, some stakeholders demand a causal relationship with the IMP (i.e. an adverse reaction). Stopping rules for a cohort are one serious adverse reaction or ≥50% of subjects experiencing any adverse reaction of moderate or severe intensity. CONSEQUENCES: The application of this consensus resulted in a reduction in protocol deficiencies issued by the competent authority.

Expression of type I interferon by splenic macrophages suppresses adaptive immunity during sepsis.

Early during Gram-negative sepsis, excessive release of pro-inflammatory cytokines can cause septic shock that is often followed by a state of immune paralysis characterized by the failure to mount adaptive immunity towards secondary microbial infections. Especially, the early mechanisms responsible for such immune hypo-responsiveness are unclear. Here, we show that TLR4 is the key immune sensing receptor to initiate paralysis of T-cell immunity after bacterial sepsis. Downstream of TLR4, signalling through TRIF but not MyD88 impaired the development of specific T-cell immunity against secondary infections. We identified type I interferon (IFN) released from splenic macrophages as the critical factor causing T-cell immune paralysis. Early during sepsis, type I IFN acted selectively on dendritic cells (DCs) by impairing antigen presentation and secretion of pro-inflammatory cytokines. Our results reveal a novel immune regulatory role for type I IFN in the initiation of septic immune paralysis, which is distinct from its well-known immune stimulatory effects. Moreover, we identify potential molecular targets for therapeutic intervention to overcome impairment of T-cell immunity after sepsis.