Pacritinib abrogates the lupus phenotype in ABIN1[D485N] mice.

OBJECTIVE: The aim of the study was to investigate whether the IRAK1/JAK2/Flt3 inhibitor pacritinib prevents disease development in the lupus-prone ABIN1[D485N] knock-in mouse. METHODS: ABIN1[D485N] knock-in mice aged 8 weeks were fed for 10 weeks on a diet containing pacritinib. Body weight was monitored, and serum collected at the end to measure pacritinib, autoantibody and immunoglobulin levels. Splenic immune cell populations were analysed, and the kidney, liver and lungs examined for pathology. RESULTS: Pacritinib prevented multiple facets of the lupus phenotype in ABIN1[D485N] knock-in mice, including splenomegaly, expansion of splenic germinal centre B cells, follicular T helper cells, and neutrophils, elevated serum levels of double-stranded DNA antibodies and immunoglobulins, glomerular IgA and lung inflammation. CONCLUSIONS: Pacritinib may be useful for the treatment of multiorgan inflammation in patients with lupus.

Observing pedestrian-vehicle traffic conflicts in school zones to evaluate the effectiveness of road safety interventions and reduce injuries in Ghana, Vietnam, and Mexico, 2019-2021.

BACKGROUND: Daily more than 3,000 children are injured or killed on the road, often along the school route. Road traffic crashes and resulting injuries are preventable. More can be done to reduce injuries and save lives. Traffic Conflict Techniques (TCTs) are simple methods of collecting observational data to evaluate the effectiveness of road safety interventions through counting and analyzing traffic conflicts. A TCT Toolkit was developed and piloted to analyze pedestrian-vehicle traffic conflicts in school zones in low- and middle-income countries. METHODS: Three non-governmental organizations in Ghana, Vietnam, and Mexico applied three TCTs from the TCT Toolkit to collect traffic conflict data before (pre-intervention) and after (post-intervention) road safety intervention implementation. As the number of traffic conflicts was often less than 100, confidence intervals (CIs) based on gamma distributions were calculated for the traffic conflict rate. Using the calculated traffic conflict rate, the difference between pre- and post-intervention rates was assessed by determining overlap of the CIs. When CIs did not overlap, the difference was said to be statistically significant at the 0.05 level. RESULTS: For each method, results indicated a decrease in traffic conflicts between pre- and post-intervention data collection periods. Pre- and post-intervention traffic conflict rates with non-overlapping CIs demonstrated the results were statistically significant, providing evidence that the road safety interventions were effective. CONCLUSIONS: TCTs are relatively low-cost and simple techniques that provide an opportunity to base road safety improvement decisions on real-world data. TCTs are effective in objectively evaluating road safety interventions and can help decision-makers evaluate strategies for improving road safety, preventing injuries and saving lives.

IKKß is required for the formation of the NLRP3 inflammasome.

The rapid formation and activation of the NLRP3 inflammasome is induced by co-stimulation with LPS and nigericin. It requires the LPS-stimulated activation of IKKß, which exerts its effects independently of de novo gene transcription, protein translation and other protein kinases activated by IKKß. IKKß is not required for the nigericin-induced dispersion of the trans-Golgi network (TGN), but to bring NLRP3 in proximity with TGN38. The nigericin-induced dispersion of the Golgi is enhanced by co-stimulation with LPS, and this enhancement is IKKß-dependent. Prolonged stimulation with LPS to increase the expression of NLRP3, followed by stimulation with nigericin, produced larger TGN38-positive puncta, and the ensuing activation of the NLRP3 inflammasome was also suppressed by IKKß inhibitors added prior to stimulation with nigericin. IKKß therefore has a key role in recruiting NLRP3 to the dispersed TGN, leading to the formation and activation of the NLRP3 inflammasome.

HOIL-1-catalysed, ester-linked ubiquitylation restricts IL-18 signaling in cytotoxic T cells but promotes TLR signalling in macrophages.

The atypical E3 ligase HOIL-1 forms ester bonds between ubiquitin and serine/threonine residues in proteins, but the physiological roles of this unusual modification are unknown. We now report that IL-18 signalling leading to the production of interferon γ (IFNγ) and granulocyte-macrophage colony-stimulating factor (GM-CSF) is enhanced in cytotoxic T cells from knock-in mice expressing the E3 ligase-inactive HOIL-1[C458S] mutant, demonstrating that the formation of HOIL-1-catalysed ester-linked ubiquitin bonds restricts the activation of this pathway. We show that the interaction of IRAK2 with TRAF6 is required for IL-18-stimulated IFN-γ and GM-CSF production, and that the increased production of these cytokines in cytotoxic T cells from HOIL-1[C458S] mice correlates with an increase in both the number and size of the Lys63/Met1-linked hybrid ubiquitin chains attached to IRAK2 in these cells. In contrast, the secretion of IL-12 and IL-6 and the formation of il-12 and il-6 mRNA induced in bone marrow-derived macrophages (BMDMs) by prolonged stimulation with TLR-activating ligands that signal via myddosomes, which also requires the interaction of IRAK2 with TRAF6, were not increased but modestly reduced in HOIL-1[C458S] BMDM. The decreased production of these cytokines correlated with reduced ubiquitylation of IRAK2. Our results establish that changes in HOIL-1-catalysed ester-linked ubiquitylation can promote or reduce cytokine production depending on the ligand, receptor and immune cell and may be explained by differences in the ubiquitylation of IRAK2.