Association of Bowel Urgency With Quality-of-Life Measures in Patients With Moderately-to-Severely Active Ulcerative Colitis: Results From Phase 3 LUCENT-1 (Induction) and LUCENT-2 (Maintenance) Studies.

Background: Improvement in bowel urgency (BU) was associated with better clinical outcomes in phase 3 LUCENT-1 (induction) and LUCENT-2 (maintenance) studies in moderately-to-severely active ulcerative colitis (UC). We assessed association of BU with quality-of-life (QoL) outcomes. Methods: LUCENT-1: 1162 patients randomized 3:1 to intravenous mirikizumab 300 mg or placebo every 4 weeks (Q4W) for 12 weeks. LUCENT-2: 544 mirikizumab induction responders re-randomized 2:1 to subcutaneous mirikizumab 200 mg or placebo Q4W through Week (W) 40 (W52 of continuous treatment). Patients reported BU severity in the past 24 hours using a validated Urgency Numeric Rating Scale (NRS). In patients with baseline Urgency NRS ≥3, the association between BU Clinically Meaningful Improvement (CMI; ≥3-point decrease) and remission (score 0 or 1) with patient-reported outcomes was assessed at W12 and W52. Results: A significantly greater proportion of patients with versus without BU Remission achieved IBDQ remission (W12: 87.3% vs 42.7%, P < .0001; W52: 91.4% vs 45.5%, p < .0001). Similarly, BU Remission was associated with more patients achieving CMI in SF-36 Physical Component Summary (W12: 69.0% vs 44.4%, P < .0001; W52: 77.5% vs 42.1%, P < .0001) and Mental Component Summary (W12: 53.5% vs 41.0%, P = .0019; W52: 62.0% vs 38.3%, P < .0001) scores. At W12 and W52, patients with BU CMI or Remission showed significant improvements in EQ-5D-5L and Work Productivity and Activity Impairment:UC scores. Significant improvements were also seen in fatigue, abdominal pain, and nocturnal stool. Conclusions: In patients with moderately-to-severely active UC, improvement in BU was associated with improved QoL in phase 3 LUCENT-1 and LUCENT-2 studies. Clinical Studies: LUCENT-1: NCT03518086; LUCENT-2: NCT03524092.

The mechanism of RNA capping by SARS-CoV-2.

The RNA genome of SARS-CoV-2 contains a 5' cap that facilitates the translation of viral proteins, protection from exonucleases and evasion of the host immune response1-4. How this cap is made in SARS-CoV-2 is not completely understood. Here we reconstitute the N7- and 2'-O-methylated SARS-CoV-2 RNA cap (7MeGpppA2'-O-Me) using virally encoded non-structural proteins (nsps). We show that the kinase-like nidovirus RdRp-associated nucleotidyltransferase (NiRAN) domain5 of nsp12 transfers the RNA to the amino terminus of nsp9, forming a covalent RNA-protein intermediate (a process termed RNAylation). Subsequently, the NiRAN domain transfers the RNA to GDP, forming the core cap structure GpppA-RNA. The nsp146 and nsp167 methyltransferases then add methyl groups to form functional cap structures. Structural analyses of the replication-transcription complex bound to nsp9 identified key interactions that mediate the capping reaction. Furthermore, we demonstrate in a reverse genetics system8 that the N terminus of nsp9 and the kinase-like active-site residues in the NiRAN domain are required for successful SARS-CoV-2 replication. Collectively, our results reveal an unconventional mechanism by which SARS-CoV-2 caps its RNA genome, thus exposing a new target in the development of antivirals to treat COVID-19.

The mechanism of RNA capping by SARS-CoV-2.

The SARS-CoV-2 RNA genome contains a 5'-cap that facilitates translation of viral proteins, protection from exonucleases and evasion of the host immune response1-4. How this cap is made is not completely understood. Here, we reconstitute the SARS-CoV-2 7MeGpppA2'-O-Me-RNA cap using virally encoded non-structural proteins (nsps). We show that the kinase-like NiRAN domain5 of nsp12 transfers RNA to the amino terminus of nsp9, forming a covalent RNA-protein intermediate (a process termed RNAylation). Subsequently, the NiRAN domain transfers RNA to GDP, forming the cap core structure GpppA-RNA. The nsp146 and nsp167 methyltransferases then add methyl groups to form functional cap structures. Structural analyses of the replication-transcription complex bound to nsp9 identified key interactions that mediate the capping reaction. Furthermore, we demonstrate in a reverse genetics system8 that the N-terminus of nsp9 and the kinase-like active site residues in the NiRAN domain are required for successful SARS-CoV-2 replication. Collectively, our results reveal an unconventional mechanism by which SARS-CoV-2 caps its RNA genome, thus exposing a new target in the development of antivirals to treat COVID-19.

A Legionella effector ADP-ribosyltransferase inactivates glutamate dehydrogenase.

ADP-ribosyltransferases (ARTs) are a widespread superfamily of enzymes frequently employed in pathogenic strategies of bacteria. Legionella pneumophila, the causative agent of a severe form of pneumonia known as Legionnaire's disease, has acquired over 330 translocated effectors that showcase remarkable biochemical and structural diversity. However, the ART effectors that influence L. pneumophila have not been well defined. Here, we took a bioinformatic approach to search the Legionella effector repertoire for additional divergent members of the ART superfamily and identified an ART domain in Legionella pneumophila gene0181, which we hereafter refer to as Legionella ADP-Ribosyltransferase 1 (Lart1) (Legionella ART 1). We show that L. pneumophila Lart1 targets a specific class of 120-kDa NAD+-dependent glutamate dehydrogenase (GDH) enzymes found in fungi and protists, including many natural hosts of Legionella. Lart1 targets a conserved arginine residue in the NAD+-binding pocket of GDH, thereby blocking oxidative deamination of glutamate. Therefore, Lart1 could be the first example of a Legionella effector which directly targets a host metabolic enzyme during infection.

Biochemical-immunological hybrid biosensor based on two-dimensional chromatography for on-site sepsis diagnosis.

A hybrid-biosensor system that can simultaneously fulfill the immunoassay for protein markers (e.g., C-reactive protein (CRP) and procalcitonin (PCT)) and the enzyme assay for metabolic substances (e.g., lactate) in the same sepsis-based sample has been devised. Such a challenge was pursued through the installation of an enzyme-reaction zone on the signal pad of the typical immuno-strip for the rapid two-dimensional (2-D)-chromatography test. To minimize the mutual interference in the hybrid assays, a pre-determined membrane site was etched in a pattern and mounted with a biochemical-reaction pad, thereby allowing a loaded sample to enter and then stay in the pad for a colored-signal production over the course of an immunoassay. By employing such a constructed system, a serum sample was analyzed according to the vertical direction flowing along the strip, which supplied lactate to the biochemical-reaction zone and then protein markers to the immunological-binding area that was pre-coated with capture antibodies. Thereafter, the enzyme-signal tracers for the immunoassay and the substrate solution were sequentially furnished using a horizontal path for the tracing of the immune complexes that were formed with CRP or PCT. The color signal that was produced from each assay was detected at a pre-determined time and quantified on a smartphone-based detector. Under the optimal conditions, the dynamic ranges for the analytes covered the respective clinical ranges, and the total coefficient of variation was between 8.6% and 13.3%. The hybrid biosensor further showed a high correlation (R2 > 0.95) with the reference systems for the target markers.