A novel role for granzymes in anti-tumor immunity

The cytotoxic properties of granzymes are well established, though recent publications suggest additional roles for granzymes in immunity. We demonstrated that granzymes can act as regulators of cross-presentation by dendritic cells by inducing critical “eat-me” signals on the dying tumor cell, resulting in efficient phagocytosis of cell-associated tumor antigen

Delay discounting and substance use treatment outcomes: A systematic review focused on treatment outcomes and discounting methodology

Introduction Delay discounting—the tendency to choose small, immediate rewards over larger, delayed rewards—is robustly associated with substance use. Delay discounting may present challenges in treatment for substance use disorders, as individuals with elevated discounting may struggle to wait for the long-term rewards that come from abstinence, which may yield poorer treatment outcomes. However, evidence on the role of discounting in treatment outcomes has been inconsistent. The study conducted a systematic review of the literature to characterize the prospective effects of delay discounting measured pre-treatment on substance use treatment outcomes, with a focus on characterizing findings across: 1) type of treatment outcome and 2) methodology used to assess and characterize discounting. Method A systematic literature search identified N = 17 studies that examined the association between delay discounting at treatment entry (pre-treatment) and substance use treatment outcomes. Findings were reported across the following substance use treatment outcomes: abstinence, relapse, use frequency and related problems, and treatment adherence. Findings regarding discounting methodology were reported by type of discounting measure (adjusting choice task, fixed choice task, or experiential task) and parameter used to characterize discounting (k, log transformed k (lnk), and area under the curve). Results Delay discounting at treatment entry was not consistently associated with substance use treatment outcomes when examined across all studies overall (47 %) or by treatment outcome (0–40 % for most outcomes). The majority of studies (64 %) that used an adjusting choice, computer-based task reported a significant association between discounting and treatment outcomes, whereas few studies that used a fixed choice or experiential task reported significant associations with treatment outcomes (0–25 %). Most studies (71 %) that used the lnk parameter to characterize discounting reported significant associations between discounting and a range of treatment outcomes. In contrast, few studies that used k or AUC (25–33 %) reported significant associations between discounting and treatment outcomes. Conclusion When examined overall and by treatment outcome, evidence did not consistently indicate that delay discounting was prospectively associated with substance use treatment outcomes. However, delay discounting at treatment entry was more commonly associated with a variety of poorer treatment outcomes when researchers used more fine-grained methods to characterize discounting

Residual active granzyme B in cathepsin C–null lymphocytes is sufficient for perforin-dependent target cell apoptosis

Cathepsin C activates serine proteases expressed in hematopoietic cells by cleaving an N-terminal dipeptide from the proenzyme upon granule packaging. The lymphocytes of cathepsin C–null mice are therefore proposed to totally lack granzyme B activity and perforin-dependent cytotoxicity. Surprisingly, we show, using live cell microscopy and other methodologies, that cells targeted by allogenic CD8+ cytotoxic T lymphocyte (CTL) raised in cathepsin C–null mice die through perforin-dependent apoptosis indistinguishable from that induced by wild-type CTL. The cathepsin C–null CTL expressed reduced but still appreciable granzyme B activity, but minimal granzyme A activity. Also, in contrast to mice with inactivation of both their granzyme A/B genes, cathepsin C deficiency did not confer susceptibility to ectromelia virus infection in vivo. Overall, our results indicate that although cathepsin C clearly generates the majority of granzyme B activity, some is still generated in its absence, pointing to alternative mechanisms for granzyme B processing and activation. Cathepsin C deficiency also results in considerably milder immune deficiency than perforin or granzyme A/B deficiency

Cytotoxic T lymphocyte–induced killing in the absence of granzymes A and B is unique and distinct from both apoptosis and perforin-dependent lysis

Cytotoxic T lymphocyte (CTL)–induced death triggered by the granule exocytosis pathway involves the perforin-dependent delivery of granzymes to the target cell. Gene targeting has shown that perforin is essential for this process; however, CTL deficient in the key granzymes A and B maintain the ability to kill their targets by granule exocytosis. It is not clear how granzyme AB−/− CTLs kill their targets, although it has been proposed that this occurs through perforin-induced lysis. We found that purified granzyme B or CTLs from wild-type mice induced classic apoptotic cell death. Perforin-induced lysis was far more rapid and involved the formation of large plasma membrane protrusions. Cell death induced by granzyme AB−/− CTLs shared similar kinetics and morphological characteristics to apoptosis but followed a distinct series of molecular events. Therefore, CTLs from granzyme AB−/− mice induce target cell death by a unique mechanism that is distinct from both perforin lysis and apoptosis

A clathrin/dynamin- and mannose-6-phosphate receptor–independent pathway for granzyme B–induced cell death

The 280-kD cation-independent mannose-6-phosphate receptor (MPR) has been shown to play a role in endocytic uptake of granzyme B, since target cells overexpressing MPR have an increased sensitivity to granzyme B–mediated apoptosis. On this basis, it has been proposed that cells lacking MPR are poor targets for cytotoxic lymphocytes that mediate allograft rejection or tumor immune surveillance. In the present study, we report that the uptake of granzyme B into target cells is independent of MPR. We used HeLa cells overexpressing a dominant-negative mutated (K44A) form of dynamin and mouse fibroblasts overexpressing or lacking MPR to show that the MPR/clathrin/dynamin pathway is not required for granzyme B uptake. Consistent with this observation, cells lacking the MPR/clathrin pathway remained sensitive to granzyme B. Exposure of K44A-dynamin–overexpressing and wild-type HeLa cells to granzyme B with sublytic perforin resulted in similar apoptosis in the two cell populations, both in short and long term assays. Granzyme B uptake into MPR-overexpressing L cells was more rapid than into MPR-null L cells, but the receptor-deficient cells took up granzyme B through fluid phase micropinocytosis and remained sensitive to it. Contrary to previous findings, we also demonstrated that mouse tumor allografts that lack MPR expression were rejected as rapidly as tumors that overexpress MPR. Entry of granzyme B into target cells and its intracellular trafficking to induce target cell death in the presence of perforin are therefore not critically dependent on MPR or clathrin/dynamin-dependent endocytosis

Oceanographic Structure and Light Levels Drive Patterns of Sound Scattering Layers in a Low-Latitude Oceanic System

Several factors have been reported to structure the spatial and temporal patterns of sound scattering layers, including temperature, oxygen, salinity, light, and physical oceanographic conditions. In this study, we examined the spatiotemporal variability of acoustically detected sound scattering layers in the northern Gulf of Mexico to investigate the drivers of this variability, including mesoscale oceanographic features [e.g., Loop Current-origin water (LCOW), frontal boundaries, and Gulf Common Water]. Results indicate correlations in the vertical position and acoustic backscatter intensity of sound scattering layers with oceanographic conditions and light intensity. LCOW regions displayed consistent decreases, by a factor of two and four, in acoustic backscatter intensity in the upper 200 m relative to frontal boundaries and Gulf Common Water, respectively. Sound scattering layers had greater backscatter intensity at night in comparison to daytime (25x for frontal boundaries, 17x for LCOW, and 12x for Gulf Common Water). The importance of biotic (primary productivity) and abiotic (sea surface temperature, salinity) factors varied across oceanographic conditions and depth intervals, suggesting that the patterns in distribution and behavior of mesopelagic assemblages in low-latitude, oligotrophic ecosystems can be highly dynamic

LD4PE: A Competency-based Guide to Linked Data Principles and Practices

The IMLS-funded Linked Data for Professional Education (LD4PE) project has developed a competency-based prototype referatory of Learning Resources for teaching and learning practices in the design, implementation, and management of Linked Data. This report summarizes the work of the project in developing: 1) an RDF-modeled “Competency Index for Linked Data” (Index) based on the Achievements Standards Network Description Language (ASN-DL) for describing formally promulgated competencies and benchmarks; 2) an openly available, web-based tool set to support the management of the Index; the generation of RDF metadata about Learning Resources; the packaging and arrangement of selected Learning Resources by users in “Saved Sets”; and the creation of learning trajectory maps expressing curricular structures or personal learning journeys superimposed over the competency framework through the integration of these elements as WordPress custom posts and taxonomies on the LD4PE website; 3) a set of cataloged Learning Resources that have been mapped to the competencies and benchmarks of the Index to support competency-based resource discovery by teachers, trainers and learners; 4) the LD4PE project website (http://explore.dublincore.net), which will be managed by the Dublin Core Metadata Initiative (DCMI) as part of its educational agenda; and 5) a set of Best Practices describing the infrastructure and policies developed for the project that others can reuse in mapping future knowledge domains in a similar manner

Single-Molecule Imaging Reveals Aβ42:Aβ40 Ratio-Dependent Oligomer Growth on Neuronal Processes

AbstractSoluble oligomers of the amyloid-β peptide have been implicated as proximal neurotoxins in Alzheimer’s disease. However, the identity of the neurotoxic aggregate(s) and the mechanisms by which these species induce neuronal dysfunction remain uncertain. Physiologically relevant experimentation is hindered by the low endogenous concentrations of the peptide, the metastability of Aβ oligomers, and the wide range of observed interactions between Aβ and biological membranes. Single-molecule microscopy represents one avenue for overcoming these challenges. Using this technique, we find that Aβ binds to primary rat hippocampal neurons at physiological concentrations. Although amyloid-β(1–40) as well as amyloid-β(1–42) initially form larger oligomers on neurites than on glass slides, a 1:1 mix of the two peptides result in smaller neurite-bound oligomers than those detected on-slide or for either peptide alone. With 1 nM peptide in solution, Aβ40 oligomers do not grow over the course of 48 h, Aβ42 oligomers grow slightly, and oligomers of a 1:1 mix grow substantially. Evidently, small Aβ oligomers are capable of binding to neurons at physiological concentrations and grow at rates dependent on local Aβ42:Aβ40 ratios. These results are intriguing in light of the increased Aβ42:Aβ40 ratios shown to correlate with familial Alzheimer’s disease mutations