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result(s) for
"Probst, Sabine"
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Fe65-PTB2 Dimerization Mimics Fe65-APP Interaction
by
Kins, Stefan
,
Haubrich, Kevin
,
Eggert, Simone
in
AICD
,
Alzheimer's disease
,
Amyloid precursor protein
2017
Physiological function and pathology of the Alzheimer's disease causing amyloid precursor protein (APP) are correlated with its cytosolic adaptor Fe65 encompassing a WW and two phosphotyrosine-binding domains (PTBs). The C-terminal Fe65-PTB2 binds a large portion of the APP intracellular domain (AICD) including the GYENPTY internalization sequence fingerprint. AICD binding to Fe65-PTB2 opens an intra-molecular interaction causing a structural change and altering Fe65 activity. Here we show that in the absence of the AICD, Fe65-PTB2 forms a homodimer in solution and determine its crystal structure at 2.6 Å resolution. Dimerization involves the unwinding of a C-terminal α-helix that mimics binding of the AICD internalization sequence, thus shielding the hydrophobic binding pocket. Specific dimer formation is validated by nuclear magnetic resonance (NMR) techniques and cell-based analyses reveal that Fe65-PTB2 together with the WW domain are necessary and sufficient for dimerization. Together, our data demonstrate that Fe65 dimerizes via its APP interaction site, suggesting that besides intra- also intermolecular interactions between Fe65 molecules contribute to homeostatic regulation of APP mediated signaling.
Journal Article
Tumor immunoevasion via acidosis-dependent induction of regulatory tumor-associated macrophages
by
Schmitt, Edgar
,
Luther, Natascha
,
von Stebut, Esther
in
631/250/2161
,
631/250/2502/248
,
631/250/580
2018
Many tumors evolve sophisticated strategies to evade the immune system, and these represent major obstacles for efficient antitumor immune responses. Here we explored a molecular mechanism of metabolic communication deployed by highly glycolytic tumors for immunoevasion. In contrast to colon adenocarcinomas, melanomas showed comparatively high glycolytic activity, which resulted in high acidification of the tumor microenvironment. This tumor acidosis induced Gprotein–coupled receptor–dependent expression of the transcriptional repressor ICER in tumor-associated macrophages that led to their functional polarization toward a non-inflammatory phenotype and promoted tumor growth. Collectively, our findings identify a molecular mechanism of metabolic communication between non-lymphoid tissue and the immune system that was exploited by high-glycolytic-rate tumors for evasion of the immune system.
Tumors can vary in both their control by immunosurveillance and their glycolytic activity. Bopp and colleagues demonstrate that highly glycolytic tumors acidify their microenvironment and use this to initiate a mechanism of localized immunosuppression.
Journal Article
Global carbon sequestration through continental chemical weathering in a climatic change context
by
Probst, Jean-Luc
,
Lechuga-Crespo, Juan Luis
,
Sauvage, Sabine
in
704/47
,
704/47/4112
,
Carbon dioxide
2021
This study simulates carbon dioxide (CO
2
) sequestration in 300 major world river basins (about 70% of global surface area) through carbonates dissolution and silicate hydrolysis. For each river basin, the daily timescale impacts under the RCP 2.6 and RCP 8.5 climate scenarios were assessed relative to a historical baseline (1969–1999) using a cascade of models accounting for the hydrological evolution under climate change scenarios. Here we show that the global temporal evolution of the CO
2
uptake presents a general increase in the annual amount of CO
2
consumed from 0.247 ± 0.045 Pg C year
−1
to 0.261 and 0.273 ± 0.054 Pg C year
−1
, respectively for RCP 2.6 and RCP 8.5. Despite showing a general increase in the global daily carbon sequestration, both climate scenarios show a decrease between June and August. Such projected changes have been mapped and evaluated against changes in hydrology, identifying hot spots and moments for the annual and seasonal periods.
Journal Article
Scientific literature on carbon dioxide removal revealed as much larger through AI-enhanced systematic mapping
by
Cowie, Annette
,
Renforth, Phil
,
van der Spek, Mijndert
in
704/106
,
706/648
,
Artificial intelligence
2025
Carbon dioxide removal plays an important role in any strategy to limit global warming to well below 2 °C. Keeping abreast with the scientific evidence using rigorous evidence synthesis methods is an important prerequisite for sustainably scaling these methods. Here, we use artificial intelligence to provide a comprehensive systematic map of carbon dioxide removal research. We find a total of 28,976 studies on carbon dioxide removal—3–4 times more than previously suggested. Growth in research is faster than for the field of climate change research as a whole, but very concentrated in specific areas—such as biochar, certain research methods like lab and field experiments, and particular regions like China. Patterns of carbon dioxide removal research contrast with trends in patenting and deployment, highlighting the differing development stages of these technologies. As carbon dioxide removal gains importance for the Paris climate goals, our systematic map can support rigorous evidence synthesis for the IPCC and other assessments.
Journal Article
CD27 expression on Treg cells limits immune responses against tumors
2022
Regulatory T cells (Tregs) suppress immune responses and thus contribute to immune homeostasis. On the downside, Tregs also limit immune responses against tumors promoting the progression of cancer. Among the many mechanisms implied in Treg-mediated suppression, the inhibition of dendritic cells (DCs) has been shown to be central in peripheral tolerance induction as well as in cancers. We have shown previously that the maintenance of peripheral T cell tolerance critically depends on cognate interactions between Tregs and DCs and that the CTL priming by unsuppressed steady state DCs is mediated via CD70. Here, we have investigated whether the CD70/CD27 axis is also involved in Treg-mediated suppression of anti-tumor immunity. Using a mixed bone marrow chimeric mouse model in which we can deplete regulatory T cells in a temporally controlled fashion, we show that Treg-expressed CD27 prevents the breakdown of peripheral tolerance and limits anti-tumor immunity. Furthermore, ablation of Treg expressed CD27 acts synergistically with PD-1 checkpoint inhibition to improve CTL mediated immunity against a solid tumor. Our data thus identify Treg-expressed CD27 as a potential target in cancer immunotherapy.Key messagesTreg expressed CD27 maintains steady state DC tolerogenicTreg expressed CD27 limits anti-tumor immunityAblation of Treg expressed CD27 synergizes with PD-1 blockade to improve CTL mediated tumor control
Journal Article
Olive Oil as a Transport Medium for Bioactive Molecules of Plants?—An In Situ Study
by
Kölling-Speer, Isabelle
,
Basche, Sabine
,
Hille, Kristin
in
Analysis
,
Animals
,
Anti-Bacterial Agents - analysis
2023
(1) Caries and erosions still remain a challenge for preventive dentistry. Certain plant extracts have shown beneficial effects in preventive dentistry. The aim of this study was to evaluate the antibacterial, anti-adherent and erosion-protective properties of ellagic acid (EA) as a polyphenolic agent. The combination with olive oil was investigated additionally to verify a possible improved bioactive effect of EA. (2) An in situ study was carried out with six subjects. Individual splints were prepared with bovine enamel specimens. The splints were worn for 1 min (pellicle formation time). Thereafter, 10 min rinses were performed with EA in water/in oil. Bacterial adherence was evaluated by fluorescence microscopy (DAPI, ConA, BacLight) after an 8 h oral exposition time. Additionally, the splints were worn for 30 min to quantify demineralization processes. The ultrastructure of the pellicle was investigated after an oral exposure time of 2 h under a transmission electron microscope. Statistical analysis was performed by Kruskal–Wallis tests, Mann–Whitney U tests and Bonferroni–Holm correction. (3) Rinsing with EA led to a significant reduction of adherent vital and dead bacteria. The combination with olive oil did not improve these outcomes. The assessment of glucan structures after rinsing with EA in water showed significant effects. Significant differences were observed for both rinses in calcium release at pH 3.0. After rinsing with EA in oil, significantly less calcium was released compared to rinsing with EA in water (pH = 3.0). (4) Olive oil is not suitable as a transport medium for lipophilic polyphenols. EA has anti-adherent and antibacterial properties in situ. EA also shows erosion-protective effects, which can be enhanced in combination with olive oil depending on the pH value. Ellagic acid has a neutral pH and could be an opportunity in the treatment of specific patient groups (xerostomia or mucositis).
Journal Article
Sex-specific effects of TLR9 promoter variants on spontaneous clearance of HCV infection
2017
ObjectiveAs pathogen sensors, Toll-like receptors (TLR) play a role in the first defence line during HCV infection. However, the impact of the DNA sensor TLR9 on the natural course of HCV infection is unknown. To address this, TLR9 promoter polymorphisms (single nucleotide polymorphisms (SNPs)) rs187084 and rs5743836 were investigated for their effect on disease progression.DesignTherefore, the TLR9 SNPs and the interferon lambda 4 (IFNL4) rs12979860 were genotyped in chronically HCV type 1 infected (n=333), in patients who spontaneously cleared the infection (n=161), in the Swiss HCV cohort (n=1057) and the well-characterised German (n=305) and Irish (n=198) ‘anti-D’ cohorts. Functional analyses were done with promoter reporter constructs of human TLR9 in B cells and assessing TLR9 mRNA levels in whole blood of healthy volunteers.ResultsThe TLR9 rs187084 C allele was associated with spontaneous virus clearance in women of the study cohort (OR=2.15 (95% CI 1.18 to 3.90) p=0.012), of the Swiss HCV cohort (OR=2.06 (95% CI 1.02 to 4.18) p=0.044) and in both ‘anti-D’ cohorts (German: OR=2.01 (95% CI 1.14 to 3.55) p=0.016; Irish: OR=1.93 (95% CI 1.10 to 3.68) p=0.047). Multivariate analysis in the combined study and Swiss HCV cohorts supported the results (OR=1.99 (95% CI 1.30 to 3.05) p=0.002). Functional analyses revealed higher transcriptional activities for both TLR9 variants and an association of the C allele of rs5743836 with allele-specific TLR9 mRNA regulation by oestrogens in women.Conclusions TLR9 promoter SNPs are associated with the natural course of HCV infection and show higher transcriptional activities. Our results imply the DNA sensor TLR9 in natural immunity against the RNA virus, HCV.
Journal Article
Tumor-infiltrating CCR2+ inflammatory monocytes counteract specific immunotherapy
by
Langguth, Peter
,
Stassen, Michael
,
Meiser, Sophie Luise
in
Antigens
,
Cancer
,
Cancer immunotherapy
2023
Tumor development and progression is shaped by the tumor microenvironment (TME), a heterogeneous assembly of infiltrating and resident host cells, their secreted mediators and intercellular matrix. In this context, tumors are infiltrated by various immune cells with either pro-tumoral or anti-tumoral functions. Recently, we published our non-invasive immunization platform DIVA suitable as a therapeutic vaccination method, further optimized by repeated application (DIVA 2 ). In our present work, we revealed the therapeutic effect of DIVA 2 in an MC38 tumor model and specifically focused on the mechanisms induced in the TME after immunization. DIVA 2 resulted in transient tumor control followed by an immune evasion phase within three weeks after the initial tumor inoculation. High-dimensional flow cytometry analysis and single-cell mRNA-sequencing of tumor-infiltrating leukocytes revealed cytotoxic CD8 + T cells as key players in the immune control phase. In the immune evasion phase, inflammatory CCR2 + PDL-1 + monocytes with immunosuppressive properties were recruited into the tumor leading to suppression of DIVA 2 -induced tumor-reactive T cells. Depletion of CCR2 + cells with specific antibodies resulted in prolonged survival revealing CCR2 + monocytes as important for tumor immune escape in the TME. In summary, the present work provides a platform for generating a strong antigen-specific primary and memory T cell immune response using the optimized transcutaneous immunization method DIVA 2 . This enables protection against tumors by therapeutic immune control of solid tumors and highlights the immunosuppressive influence of tumor infiltrating CCR2 + monocytes that need to be inactivated in addition for successful cancer immunotherapy.
Journal Article
Development of a p62 biodegrader for autophagy targeted degradation
2025
Autophagy-based targeted degradation offers a powerful complement to proteasomal degradation leveraging the capacity and versatility of lysosomes to degrade complex cargo. However, it remains unclear which components of the autophagy-lysosomal pathway are most effective for targeted degradation. Here, we describe two orthogonal induced-proximity strategies to identify autophagy effectors capable of degrading organelles and soluble targets. Recruitment of autophagy cargo receptors, ATG8-like proteins, or the kinases ULK1 and TBK1 is sufficient to trigger mitophagy, while only autophagy cargo receptors capable of self-oligomerization degrade soluble cytosolic proteins. We further report a single-domain antibody against p62 and its use as a heterobifunctional degrader to clear mitochondria. Fusing the p62 single-domain antibody to PINK1 enables selective targeting of damaged mitochondria. Our study highlights the importance of avidity for targeted autophagy and suggests that autophagy cargo receptors are attractive entry points for the development of heterobifunctional degraders for organelles or protein aggregates.
Using proximity-based screening, protein engineering, and structural analysis, this study describes the development of a p62-based biodegrader for the clearance of organelles and aggregated proteins by autophagy-targeted degradation.
Journal Article