Oncogenic signaling and mechanisms of immune evasion in aggressive B-cell lymphomas

B cel lymfomen kunnen ontstaan tijdens verschillende fasen van de B cel ontwikkeling en vormen een zeer heterogene groep maligniteiten. Diffuus grootcellig B cel lymfoom (DLBCL) en mantelcellymfoom (MCL) vallen beiden onder de groep van de agressieve non-Hodgkin lymfomen. Aberrante activatie van diverse oncogene signaleringsroutes speelt een belangrijke rol in de pathogenese van zowel DLBCL als MCL. Herkenning van een antigen door de B-cel receptor (BCR), een membraan gebonden antilichaam, stimuleert intrinsieke signaleringsroutes die zorgen voor B cel activatie en celdeling. Daarnaast brengen B cellen Toll-like receptoren (TLRs) tot expressie waarmee ze potentieel pathogene micro-organismen of lichaamseigen stoffen die bij schade vrijkomen, kunnen herkennen. Verstoorde activatie van zowel BCR als TLR gedreven signaleringsroutes als gevolg van mutaties of epigenetische veranderingen, komt voor bij een groot deel van DLBCL en MCL gevallen. Primaire grootcellige B cel lymfomen die voorkomen op extranodale locaties waar het afweersysteem zeer sterk gereguleerd wordt, worden gekenmerkt door een hoge frequentie van activerende MYD88 en CD79B mutaties. Daarnaast maken deze lymfomen vaak gebruik van verschillende mechanismen om herkenning en eliminatie door het afweersysteem van de gastheer te ontwijken. Het beter begrijpen van de pathobiologie van deze lymfomen kan bijdragen aan de ontwikkeling van specifieke therapieën voor de behandeling van deze agressieve lymfomen

Oncogenic signaling and mechanisms of immune evasion in aggressive B-cell lymphomas

B cel lymfomen kunnen ontstaan tijdens verschillende fasen van de B cel ontwikkeling en vormen een zeer heterogene groep maligniteiten. Diffuus grootcellig B cel lymfoom (DLBCL) en mantelcellymfoom (MCL) vallen beiden onder de groep van de agressieve non-Hodgkin lymfomen. Aberrante activatie van diverse oncogene signaleringsroutes speelt een belangrijke rol in de pathogenese van zowel DLBCL als MCL. Herkenning van een antigen door de B-cel receptor (BCR), een membraan gebonden antilichaam, stimuleert intrinsieke signaleringsroutes die zorgen voor B cel activatie en celdeling. Daarnaast brengen B cellen Toll-like receptoren (TLRs) tot expressie waarmee ze potentieel pathogene micro-organismen of lichaamseigen stoffen die bij schade vrijkomen, kunnen herkennen. Verstoorde activatie van zowel BCR als TLR gedreven signaleringsroutes als gevolg van mutaties of epigenetische veranderingen, komt voor bij een groot deel van DLBCL en MCL gevallen. Primaire grootcellige B cel lymfomen die voorkomen op extranodale locaties waar het afweersysteem zeer sterk gereguleerd wordt, worden gekenmerkt door een hoge frequentie van activerende MYD88 en CD79B mutaties. Daarnaast maken deze lymfomen vaak gebruik van verschillende mechanismen om herkenning en eliminatie door het afweersysteem van de gastheer te ontwijken. Het beter begrijpen van de pathobiologie van deze lymfomen kan bijdragen aan de ontwikkeling van specifieke therapieën voor de behandeling van deze agressieve lymfomen

Fur and faeces: an experimental assessment of non-invasive DNA sampling for the European pine marten

Non-invasive genetic sampling using materials such as faeces or hair can be used to monitor wildlife populations, although DNA quality is often poor. Improving sampling efficiency and minimising factors that reduce DNA quality are therefore critical. After a severe decline, the European pine marten, Martes martes, has reclaimed much of its former range in Scotland, UK. Recording this rapid range expansion requires developing techniques for accurate monitoring, but this is hampered by the species' elusive behaviour. We tested two sampling methods, hair collected from hair tubes and faeces (scat) collected along tracks, to assess the effects of key environmental and sampling variables on DNA quality and sampling efficiency. For hair, we tested the influence of hair tube location (distance from forest tracks) on collection rate and sex ratio of animals successfully sampled. For scats, we assessed the effect of time since defecation (1 to 16days) on genotyping error rates and success under two contrasting environmental conditions (exposed to rainfall or sheltered). We found no bias in the collection rate or sex ratio of animals detected by hair samples with differing proximity to forest tracks. DNA amplification failure for scats exposed to rainfall increased from 28 to 65% over the 16-day experimental period. During periods of low rainfall, the length of collection sessions could therefore be extended to increase sample number without risk of DNA degradation. Lack of bias in hair collection rates with proximity to forest tracks provides justification for tube placement close to tracks, as this reduces survey effort. These findings provide guidance for the development of efficient and cost-effective non-invasive sampling of Scottish pine martens

Saponin-based adjuvants induce cross-presentation in dendritic cells by intracellular lipid body formation

Saponin-based adjuvants (SBAs) are being used in animal and human (cancer) vaccines, as they induce protective cellular immunity. Their adjuvant potency is a factor of inflammasome activation and enhanced antigen cross-presentation by dendritic cells (DCs), but how antigen cross-presentation is induced is not clear. Here we show that SBAs uniquely induce intracellular lipid bodies (LBs) in the CD11b+ DC subset in vitro and in vivo. Using genetic and pharmacological interference in models for vaccination and in situ tumour ablation, we demonstrate that LB induction is causally related to the saponin- dependent increase in cross-presentation and T-cell activation. These findings link adjuvant activity to LB formation, aid the application of SBAs as a cancer vaccine component, and will stimulate development of new adjuvants enhancing T-cell-mediated immunity

Novel phosphatidylserine-binding molecule enhances antitumor T-cell responses by targeting immunosuppressive exosomes in human tumor microenvironments.

BACKGROUND: The human tumor microenvironment (TME) is a complex and dynamic milieu of diverse acellular and cellular components, creating an immunosuppressive environment, which contributes to tumor progression. We have previously shown that phosphatidylserine (PS) expressed on the surface of exosomes isolated from human TMEs is causally linked to T-cell immunosuppression, representing a potential immunotherapeutic target. In this study, we investigated the effect of ExoBlock, a novel PS-binding molecule, on T-cell responses in the TME. METHODS: We designed and synthesized a new compound, (ZnDPA) RESULTS: ExoBlock was able to bind PS with high avidity and was found to consistently and significantly block the immunosuppressive activity of human ovarian tumor and melanoma-associated exosomes in vitro. ExoBlock was also able to significantly enhance T cell-mediated tumor suppression in vivo in both the X-mouse and the OTX model. In the X-mouse model, ExoBlock suppressed tumor recurrence in a T cell-dependent manner. In the OTX model, ExoBlock treatment resulted in an increase in the number as well as function of CD4 and CD8 T cells in the TME, which was associated with a reduction in tumor burden and metastasis, as well as in the number of circulating PS+ exosomes in tumor-bearing mice. CONCLUSION: Our results establish that targeting exosomal PS in TMEs with ExoBlock represents a promising strategy to enhance antitumor T-cell responses

NADPH Oxidase Limits Innate Immune Responses in the Lungs in Mice

Background: Chronic granulomatous disease (CGD), an inherited disorder of the NADPH oxidase in which phagocytes are defective in generating superoxide anion and downstream reactive oxidant intermediates (ROIs), is characterized by recurrent bacterial and fungal infections and by excessive inflammation (e.g., inflammatory bowel disease). The mechanisms by which NADPH oxidase regulates inflammation are not well understood. Methodology/Principal Findings: We found that NADPH oxidase restrains inflammation by modulating redox-sensitive innate immune pathways. When challenged with either intratracheal zymosan or LPS, NADPH oxidase-deficient p47phox-/- mice and gp91phox-deficient mice developed exaggerated and progressive lung inflammation, augmented NF-kB activation, and elevated downstream pro-inflammatory cytokines (TNF-α, IL-17, and G-CSF) compared to wildtype mice. Replacement of functional NADPH oxidase in bone marrow-derived cells restored the normal lung inflammatory response. Studies in vivo and in isolated macrophages demonstrated that in the absence of functional NADPH oxidase, zymosan failed to activate Nrf2, a key redox-sensitive anti-inflammatory regulator. The triterpenoid, CDDO-Im, activated Nrf2 independently of NADPH oxidase and reduced zymosan-induced lung inflammation in CGD mice. Consistent with these findings, zymosan-treated peripheral blood mononuclear cells from X-linked CGD patients showed impaired Nrf2 activity and increased NF-kB activation. Conclusions/Significance: These studies support a model in which NADPH oxidase-dependent, redox-mediated signaling is critical for termination of lung inflammation and suggest new potential therapeutic targets for CGD

Procjena cito-/genotoksičnosti irinotekana u V79-stanicama primjenom komet-testa, mikronukleus-testa i testa kromosomskih aberacija

Irinotecan is a topoisomerase I interactive agent, widely used in the treatment of metastatic colorectal cancer. The genotoxic effects of the maximum single dose (18 μg mL-1), recommended monotherapy dose (9 μg mL-1), and recommended combined therapy dose (4.5 μg mL-1) of irinotecan were studied on V79 cells using the comet assay, chromosome aberration assay, and micronucleus test. The cells were treated with irinotecan for 2 h or 24 h. The statistical signifi cance of the results was determined using the one-way ANOVA test and a nonparametric Mann Whitney U test. The comet assay did not show dose-dependent or time-dependent effects. The chromosome aberration analysis showed large DNA rearrangements, i.e., chromosome exchanges. Although the exposed cultures showed a signifi cant increase in micronucleated cells in respect to control, no dose-dependent relation was established among the treated cultures. Timedependent effect was also not observed.Irinotekan je citotoksični lijek koji inhibira enzim DNA-topoizomerazu I. U širokoj je primjeni u terapiji metastatskog karcinoma kolona i rektuma. U uvjetima in vitro primjenom komet-testa, analize kromosomskih aberacija i mikronukleus-testa na V79-stanicama istražili smo genotoksični učinak maksimalne pojedinačne doze (18 μg mL-1), preporučene monoterapijske doze (9 μg mL-1) i preporučene doze irinotekana za kombiniranu terapiju (4,5 μg mL-1). Kulture stanica bile su tretirane irinotekanom 2 h i 24 h. Statistička značajnost određivana je jednosmjernim ANOVA-testom i neparametrijskim Mann Whitneyevim U-testom. Komet-testom nije utvrđen učinak koncentracije i/ili vremena izloženosti. Analiza kromosomskih aberacija pokazala je prisutnost izmjena kromatida, tj. porast broja triradijusa i tetraradijusa. Iako je u kulturama stanica izloženi irinotekanu opažen značajan porast broja mikronukleusa u odnosu na kontrolu, nije uočena ovisnost o dozi lijeka ni o vremenu izloženosti u opisanim eksperimentalnim uvjetima. Dobiveni rezultati upućuju na genotoksičnost irinotekana za V79-stanice. Nijednom od primijenjenih metoda nije utvrđena ovisnost učinka irinotekana o vremenu ili dozi

Mineralization of ancient carbon in the subsurface of riparian forests

Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): G02021, doi:10.1029/2007JG000482.Microbial activity in saturated, subsurface sediments in riparian forests may be supported by recent photosynthate or ancient (>500 ybp) soil organic carbon (SOC) in buried horizons. Metabolism of ancient SOC may be particularly important in riparian zones, considered denitrification hot spots, because denitrification in the riparian subsurface is often C-limited, because buried horizons intersect deep flow paths, and because low C mineralization rates can support ecosystem-relevant rates of denitrification. Buried horizons are common where alluvial processes (stream migration, overbank flow) have dominated riparian evolution. Our objectives were to determine: (1) the extent to which ancient SOC directly supports subsurface microbial activity; (2) whether different C sources support microbial activity in alluvial versus glaciofluvial riparian zones; and (3) how microbial use of ancient SOC varies with depth. In situ groundwater incubations and 14C dating of dissolved inorganic carbon revealed that ancient SOC mineralization was common, and that it constituted 31–100% of C mineralization 2.6 m deep at one site, at rates sufficient to influence landscape N budgets. Our data failed to reveal consistent spatial patterns of microbially available ancient C. Although mineralized C age increased with depth at one alluvial site, we observed ancient C metabolism 150 cm deep at a glaciofluvial site, suggesting that subsurface microbial activity in riparian zones does not vary systematically between alluvial and glaciofluvial hydrogeologic settings. These findings underscore the relevance of ancient C to contemporary ecosystem processes and the challenge of using mappable surface features to identify subsurface ecosystem characteristics or riparian zone N-sink strength.We are grateful to the Cornell Program in Biogeochemistry for graduate research grants and to the U.S. EPA for a STAR Graduate Fellowship to Noel Gurwick. Support for radiocarbon analyses also came from USDANRICGP grant 99–35102– 8266, NSF cooperative agreement OCE-9807266, and an Andrew W. Mellon Foundation grant to the Institute of Ecosystem Studies. A graduate research grant to N. Gurwick from the Theresa Heinz Scholars for Environmental Research provided salary for Pete Seitz-Rundlett

Sensitive and Specific Fluorescent Probes for Functional Analysis of the Three Major Types of Mammalian ABC Transporters

An underlying mechanism for multi drug resistance (MDR) is up-regulation of the transmembrane ATP-binding cassette (ABC) transporter proteins. ABC transporters also determine the general fate and effect of pharmaceutical agents in the body. The three major types of ABC transporters are MDR1 (P-gp, P-glycoprotein, ABCB1), MRP1/2 (ABCC1/2) and BCRP/MXR (ABCG2) proteins. Flow cytometry (FCM) allows determination of the functional expression levels of ABC transporters in live cells, but most dyes used as indicators (rhodamine 123, DiOC2(3), calcein-AM) have limited applicability as they do not detect all three major types of ABC transporters. Dyes with broad coverage (such as doxorubicin, daunorubicin and mitoxantrone) lack sensitivity due to overall dimness and thus may yield a significant percentage of false negative results. We describe two novel fluorescent probes that are substrates for all three common types of ABC transporters and can serve as indicators of MDR in flow cytometry assays using live cells. The probes exhibit fast internalization, favorable uptake/efflux kinetics and high sensitivity of MDR detection, as established by multidrug resistance activity factor (MAF) values and Kolmogorov-Smirnov statistical analysis. Used in combination with general or specific inhibitors of ABC transporters, both dyes readily identify functional efflux and are capable of detecting small levels of efflux as well as defining the type of multidrug resistance. The assay can be applied to the screening of putative modulators of ABC transporters, facilitating rapid, reproducible, specific and relatively simple functional detection of ABC transporter activity, and ready implementation on widely available instruments