BackgroundHypomethylation of the cathepsin Z locus has been proposed as an epigenetic risk factor for multiple sclerosis (MS). Cathepsin Z is a unique lysosomal cysteine cathepsin expressed primarily by antigen presenting cells. While cathepsin Z expression has been associated with neuroinflammatory disorders, a role for cathepsin Z in mediating neuroinflammation has not been previously established.MethodsExperimental autoimmune encephalomyelitis (EAE) was induced in both wildtype mice and mice deficient in cathepsin Z. The effects of cathepsin Z-deficiency on the processing and presentation of the autoantigen myelin oligodendrocyte glycoprotein, and on the production of IL-1β and IL-18 were determined in vitro from cells derived from wildtype and cathepsin Z-deficient mice. The effects of cathepsin Z-deficiency on CD4+ T cell activation, migration, and infiltration to the CNS were determined in vivo. Statistical analyses of parametric data were performed by one-way ANOVA followed by Tukey post-hoc tests, or by an unpaired Student’s t test. EAE clinical scoring was analyzed using the Mann–Whitney U test.ResultsWe showed that mice deficient in cathepsin Z have reduced neuroinflammation and dramatically lowered circulating levels of IL-1β during EAE. Deficiency in cathepsin Z did not impact either the processing or the presentation of MOG, or MOG- specific CD4+ T cell activation and trafficking. Consistently, we found that cathepsin Z-deficiency reduced the efficiency of antigen presenting cells to secrete IL-1β, which in turn reduced the ability of mice to generate Th17 responses—critical steps in the pathogenesis of EAE and MS.ConclusionTogether, these data support a novel role for cathepsin Z in the propagation of IL-1β-driven neuroinflammation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-017-0874-x) contains supplementary material, which is available to authorized users.

No abstract

No abstract

No abstract

ImportanceImmune-related adverse events (irAEs) due to immune checkpoint blockade (ICB) have been shown to be positively associated with survival. Among patients with metastatic melanoma, evidence supporting this association has been conflicting, while ipilimumab-nivolumab combination ICB has been examined only in small clinical cohorts.ObjectiveTo examine the association between irAEs and survival among patients with metastatic melanoma, in particular for those receiving combination ICB.Design, Setting, and ParticipantsA retrospective cohort of 492 consecutive patients with metastatic melanoma treated with ICB at 2 tertiary and 4 regional cancer centers in Alberta, Canada, from August 1, 2013, to May 31, 2020, was observed. Patients were aged 18 years or older with metastatic melanoma agnostic to primary site, who received 1 or more doses of an anti–programmed cell death protein 1 agent as single or combination ICB. Clinically significant irAEs requiring systemic corticosteroids and/or treatment delay were captured. To minimize immortal time bias, only patients surviving 12 weeks after ICB initiation were included in survival analyses. Statistical analysis was conducted on December 10, 2021.ExposuresDevelopment of irAEs requiring systemic corticosteroids and/or treatment delay.Main Outcomes and MeasuresThe primary outcome was overall survival (OS), with the association of irAE development with OS assessed via Kaplan-Meier and Cox proportional hazards regression analyses. The association of hospitalization for irAEs and ICB resumption after irAE with OS was examined.ResultsAmong 492 patients, the median age of those with irAEs was 61.8 years (IQR, 52.9-72.1 years), and the median age of those without irAEs was 65.5 years (IQR, 56.5-76.9 years), while sex distribution was comparable (137 of 198 men [69.2%] with irAEs vs 183 of 294 men [62.2%] without irAEs). There was an association between irAEs and OS both in the overall cohort (with irAEs: median OS, 56.3 months [95% CI, 38.2 months to not evaluable] vs without irAEs: median OS, 18.5 months [95% CI, 14.4-23.2 months]; P < .001) and in the 124 patients (25.2%) receiving combination ICB (with irAEs: median OS, 56.2 months [95% CI, 52.2 months to not evaluable] vs without irAEs: median OS, 19.0 months [95% CI, 6.6 months to not evaluable]; P < .001). Hospitalization for irAE did not alter this positive association with OS compared with outpatient treatment (median OS, not evaluable [95% CI, 31.5 months to not evaluable] vs median OS, 52.2 months [95% CI, 35.2 months to not evaluable]; P = .53), while resumption of ICB was associated with longer OS than not resuming ICB (median, 56.3 months [95% CI, 40.8 months to not evaluable] vs 31.5 months [95% CI, 21.0 months to not evaluable]; P = .009). A favorable independent association of irAEs with OS was confirmed in multivariable analysis (hazard ratio for death, 0.382 [95% CI, 0.254-0.576]; P < .001).Conclusions and RelevanceThis study suggests an association between irAEs and OS for patients with metastatic melanoma, including those treated with combination ICB and those with severe irAEs requiring hospitalization. The potential benefit associated with ICB resumption after irAEs warrants further investigation.

Recognition of pathogen-or-damage-associated molecular patterns is critical to inflammation. However, most pathogen-or-damage-associated molecular patterns exist within intact microbes/cells and are typically part of non-diffusible, stable macromolecules that are not optimally immunostimulatory or available for immune detection. Partial digestion of microbes/cells following phagocytosis potentially generates new diffusible pathogen-or-damage-associated molecular patterns, however, our current understanding of phagosomal biology would have these molecules sequestered and destroyed within phagolysosomes. Here, we show the controlled release of partially-digested, soluble material from phagolysosomes of macrophages through transient, iterative fusion-fission events between mature phagolysosomes and the plasma membrane, a process we term eructophagy. Eructophagy is most active in proinflammatory macrophages and further induced by toll like receptor engagement. Eructophagy is mediated by genes encoding proteins required for autophagy and can activate vicinal cells by release of phagolysosomally-processed, partially-digested pathogen associated molecular patterns. We propose that eructophagy allows macrophages to amplify local inflammation through the processing and dissemination of pathogen-or-damage-associated molecular patterns.

Proteolysis and the reduction of disulfides, both major components of protein degradation, are profoundly influenced by phagosomal redox conditions in macrophages. We evaluated the activation of phagocytic receptors that are known to influence activation of the phagocyte NADPH oxidase (NOX2), and its effect on phagosomal protein degrada- Phagocytosis is necessary for the destruction of pathogens, the clearance of cellular debris and the processing of exogenous protein antigen. While the hydrolysis of phagocytosed protein is not generally considered an effective antimicrobial effector, it is essential to the recycling of proteins during tissue remodeling and repair as well as the processing of major histocompatibility complex (MHC)-restricted antigens. The efficient degradation of phagocytosed protein requires the reduction of interand intra-molecular disulfides [predominantly mediated by gamma interferon-inducible lysosomal thioreductase (GILT)] and the hydrolysis of peptide bonds by lysosomal † Co-first authors.proteases such as the lysosomal cathepsins (1,2). The activities of GILT and the lysosomal proteases are not only regulated by their expression and delivery to the phagosome but also by local conditions such as pH and redox chemistries within the phagosomal microenvironment (3). Of particular note, reactive oxygen species (ROS) generated by the phagocyte NADPH oxidase (NOX2) can directly oxidize the active-site cysteines present in thiol-dependent proteases and disulfide reductases, which can dramatically decrease the efficiencies of both proteolysis and disulfide reduction of phagocytosed protein (4,5). Controlling protein degradation at multiple levels allows macrophages to fine-tune phagosomal function in response to various environmental and immune stimuli 786 www.traffic.dk

Background Metastatic uveal melanoma (MUM) is associated with poor survival and inferior response to immune checkpoint inhibitor (ICI) therapy when compared with metastatic cutaneous melanoma. Currently, prognostic biomarkers are lacking to guide treatment decisions. Patients and Methods We conducted a multicenter, retrospective cohort study using a centralized, province‐wide cancer database in Alberta, Canada. We identified 37 patients with histologically confirmed MUM who received at least one dose of single‐agent pembrolizumab or nivolumab, or combination therapy nivolumab and ipilimumab. A modified immune prognostic index (IPI), based on the previously reported lung immune prognostic index, was used to stratify patients into favorable and poor IPI groups. Survival analyses were conducted using the Kaplan–Meier method and Cox proportional hazards models, adjusting for baseline age (≥60) and ECOG performance status, to assess the associations between IPI and overall survival (OS). Time to treatment failure (TTF) was also assessed using the Kaplan–Meier method. The association between IPI and objective response rate was examined using chi‐squared tests. Logistic regression was used to determine the association between IPI and immune‐related adverse events (irAEs). Results Median OS was 15.6 (range 0.6–57.6) months with 45.9% 1‐year survival rate at a median follow‐up of 11.8 months. We found that a favorable IPI was significantly associated with OS [median 30.5 (12.0‐not reached) months in the favorable IPI group compared with 4.6 (2.1–16.0) months in the poor IPI group (p = 0.001)] (HR=4.81, 95% CI; 1.64–14.10, p = 0.004), TTF [median 5.1 (95% CI; 2.1–10.4) months in the favorable IPI group compared with 3.7 (95% CI; 1.4–6.4) months in the poor IPI group (p = 0.0191)], and irAE (HR=6.67, 95% CI; 1.32–33.69, p = 0.0220). Conclusions The modified IPI may be a useful tool in clinical practice for identifying MUM patients who are more likely to experience irAEs and realize a survival benefit from ICI treatment.