Biology subjects

Watzl, C.

Publications and source records attributed to Watzl, C..

7 recordsLinked to original sources

bioRxiv2026

2B4 co-engagement promotes serial degranulation and killing by human NK cells

Activation of Natural Killer (NK) cells depends on the stimulation of a broad range of receptors. Here we use murine NIH3T3 target cells expressing defined human NK cell ligands to stimulate different aspects of NK cell activity and identify how distinct ligand-receptor interactions regulate different aspects of NK cell activation. B7H6, MICA, and CD20-bound obinutuzumab engaging NKp30, NKG2D, or CD16, respectively, were found to be potent inducers of activity in pre-stimulated NK cells. Combination of these ligands with CD48 to also stimulate 2B4 significantly increased degranulation and cytokine secretion, while PVR engaging DNAM-1 showed favorable effects only in combination with B7H6. Activating NK cell receptors were downregulated in a ligand-specific fashion, whereas CD16 and NKp46 were found to be downregulated depending on NK cell activation induced by other receptors. Co-stimulation via 2B4 in combination with either NKp30, NKG2D, or CD16 significantly enhanced NK cells to serially degranulate and kill multiple targets. Our systematic analysis unravels the complexity of different activating NK cell receptors and provides strategies to specifically tune NK cell reactivities for therapeutic applications.

immunology↗

bioRxiv2025

Electrophysiological resting-state signatures link polygenic scores to general intelligence

Intelligence is associated with important life outcomes. Behavioral, genetic, structural, and functional brain correlates of intelligence have been studied for decades, but questions remain as to how genetics are related to trait expression and what intermediary role brain properties play. This study investigated these mediations in a representative sample of 434 individuals, comprising young and older adults. Polygenic scores (PGS) for intelligence were calculated. Resting-state EEG recordings were analyzed using graph theory quantifying functional connectivity across different frequencies. We tested whether global and local graph metrics like efficiency and clustering mediated the association between PGS and intelligence. PGS significantly predicted variance in intelligence and were related to frequency-specific graph metrics in areas predominantly located in parieto-frontal regions, which in turn were associated with intelligence. These findings, which are based on the first study linking PGS to intelligence using EEG-derived graph metrics, advance our understanding of the neurogenetics of intelligence.

neuroscience↗

bioRxiv2024

Identification of small molecule enhancers of NK cell tumoricidal activity via a tumor microenvironment-mimicking co-culture assay

The tumor microenvironment (TME) is a pro-cancerous niche harboring immunosuppressive factors that are secreted by cancer cells and the surrounding cancer-supportive tissue, such as kynurenine, prostaglandin E2 and transforming growth factor {beta} (TGF{beta}). These factors dampen the activity of cytotoxic lymphocytes like natural killer (NK) cells, allowing evasion of immune cell-mediated killing. To identify small molecules that counteract the immunosuppressive effect of the TME and restore NK cell-mediated cytotoxicity, we developed a phenotypic co-culture assay of cancer cells and primary lymphocytes suitable for medium-throughput screening. We discovered small molecules that restore NK cell-mediated cytotoxicity through diverse mechanisms. The potent TGF{beta} type I receptor (TGF{beta}R-1) inhibitor, RepSox, stood out as superior to other TGF{beta}R-1 inhibitors due to its ability to abolish the effects of both inhibitory factors used in our setup. This mode of action goes beyond TGF{beta}R-1 inhibition and is related to the simultaneous abrogation of cyclooxygenase 1 (COX1) activity.

immunology↗

bioRxiv2024

SARS-CoV-2 modulates NK cell responses via induction of HLA-E and triggers expansion of adaptive NK cells during acute infection

HLA-E expression plays a central role for modulation of NK cell function by interaction with inhibitory NKG2A and stimulatory NKG2C receptors on canonical and adaptive NK cells, respectively. Here, we demonstrate that infection of human primary lung tissue with SARS-CoV-2 leads to increased HLA-E expression and show that processing of the peptide YLQPRTFLL from the spike protein is primarily responsible for the strong, dose-dependent increase of HLA-E. Targeting the peptide site within the spike protein revealed that a single point mutation was sufficient to abrogate the increase in HLA-E expression. Spike-mediated induction of HLA-E differentially affected NK cell function: whereas degranulation, IFN-{gamma} production, and target cell cytotoxicity were enhanced in NKG2C+ adaptive NK cells, effector functions were inhibited in NKG2A+ canonical NK cells. Analysis of a cohort of COVID-19 patients in the acute phase of infection revealed that adaptive NK cells were induced irrespective of the HCMV status, challenging the paradigm that adaptive NK cells are only generated during HCMV infection. During the first week of hospitalization, patients exhibited a selective increase of early NKG2C+CD57- adaptive NK cells whereas mature NKG2C+CD57+ cells remained unchanged. Further analysis of recovered patients suggested that the adaptive NK cell response is primarily driven by a wave of early adaptive NK cells during acute infection that wanes once the infection is cleared. Together, this study suggests that NK cell responses to SARS-CoV-2 infection are majorly influenced by the balance between canonical and adaptive NK cells via the HLA-E/NKG2A/C axis.

immunology↗

bioRxiv2023

Ammonia inhibits antitumor activity of NK cells by decreasing mature perforin

Immunotherapy revolutionized cancer treatment in the last decade. Natural killer (NK) cells are one of the key host immunity components against malignant cells. Thus, they are currently extensively investigated in the field of immunotherapy of cancer. Different approaches have been developed to improve the antitumor activity of NK cells. Nonetheless, tumor microenvironment remains an obstacle to effective NK cell-based therapies. Here, we demonstrated that a cancer-conditioned medium suppresses the anti-tumor activity of NK cells. Further, we found that ammonia, a by-product of cancer cell metabolism, accumulates in the cancer-conditioned medium and tumor microenvironment. We identified that ammonia impairs the cytotoxicity of NK cells as well as the effectiveness of antibody-based and chimeric antigen receptor (CAR)-NK-based therapies in vitro. Inhibited activity of NK cells was caused by decreased levels of perforin. This effect was dependent on the lysosomotropic features of ammonia and its ability to increase pH in acidic compartments. In consequence, upon contact with ammonia the mature form of perforin was decreased in NK cells leading to their dysfunction. Our findings demonstrate that in addition to its previously described role of promoting tumor growth as a nitrogen source for tumor biomass ammonia could promote tumor escape as an NK cells immune checkpoint. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=66 SRC="FIGDIR/small/567708v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@19db6a5org.highwire.dtl.DTLVardef@1424903org.highwire.dtl.DTLVardef@c795d7org.highwire.dtl.DTLVardef@13e7a8e_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LICancer-conditioned medium suppresses the antitumor activity of NK cells C_LIO_LIAmmonia accumulates in conditioned medium and in the tumor microenvironment C_LIO_LIImpaired cytotoxicity of NK cells is caused by ammonia that decreases perforin levels C_LIO_LIAmmonia causes NK cell dysfunction C_LI

cancer biology↗

bioRxiv2020

Activating NK- receptors, homing selectins and inhibitory Siglecs recognize EBOLA-GP and HPV-L1NK

The Ebola virus glycoprotein (EBOV)-GP is extensively glycosylated. Its expression induces a physical alteration of surface adhesion molecules, which causes cell rounding and detachment of the infected cells. This phenomenon likely plays a crucial role in viral pathogenicity. In this study, we show that such morphological changes are cell line-dependent as well as dependent on the surface proteins that interact with EBOV-GP in cis and trans. We have generated data showing that natural killer (NK) cell receptors (NCRs: NKp44 and NKp46), selectins (CD62E/P/L) and inhibitory Siglecs function as receptors for Ebola-GP and human papilloma virus (HPV-L1). We used HEK293 cells transfected with Ebola-GP and recombinant fusion proteins containing the extracellular domain of each of these receptors linked to the Fc of human IgG1, which showed significant differences in their virus-binding behavior compared to HEK293 cells transfected with empty vector. Further, to demonstrate that EBOV-GP is a ligand for NKp44 and other NK-receptors, and to investigate their role in immune escape, we also used human HEK-293, HeLa- and hamster CHO-GP-transfectants. Our data show that the NK receptors NKp44 and NKp46 play a key role in recognizing EBOV (Ebolavirus) and strongly suggest that other inhibitory (Siglec-7, Siglec-5) and non-inhibitory homing receptors (P-Selectin, L-Selectin, E-Selectin, and DC-SIGNR/DC-SIGN) take part in the interaction with virus particles. In addition, we show that NKp44, and NKp46, Siglec-7, and -5, and P-, L-, E-selectins as well as of and DC-SIGNR/DC-SIGN bind to the artificial viral envelope of a lentiviral vector that contains EBOV-GP. Altogether we prove that NCRs and a range of other inhibitory and activating receptors can interact with viral envelope/capsid proteins and that such interaction could play an important role in the elimination of virus infected cells. Our findings could be used to develop new strategies for prevention and treatment of infections by these viruses. Author summaryThe innate immune system is able to recognize specifically certain virus components. Here we show that activating NK-cell receptors (NKp44, and NKp46) are involved in such interaction by using HEK293 and CHOK1 cells transfected with the Ebola virus glycoprotein (EBOV-GP) and by binding studies with purified EBOV-GP. In detail, we have found moderate to strong affinity of Siglecs (Siglec-7, and -5), selectins (P-, L-, E-Selectin) and DC-SIGNR/DC-SIGN to purified EBOV-GP, and to cells transfected with EBOV-GP as well as to the envelope of a lentiviral vector carrying the EBOV-GP. Our findings show that NKp44, and NKp46, Siglec-7, and -5, as well as P-and L-selectins have a strong affinity to EBOV-G.

immunology↗

bioRxiv2018

Single-fluorescent protein reporters allow parallel quantification of NK cell-mediated granzyme and caspase activities in single target cells

1.Natural killer (NK) cells eliminate infected and tumorigenic cells through delivery of granzymes via perforin pores or by activation of caspases via death receptors. In order to understand how NK cells combine different cell death mechanisms it is important to quantify target cell responses on a single cell level. However, currently existing reporters do not allow the measurement of several protease activities inside the same cell. Here we present a strategy for the comparison of two different proteases at a time inside individual target cells upon engagement by NK cells. We developed single-fluorescent protein reporters containing the RIEAD or the VGPD cleavage site for the measurement of granzyme B activity. We show that these two granzyme B reporters can be applied in combination with caspase-8 or caspase-3 reporters. While we did not find that caspase-8 was activated by granzyme B, our method revealed that caspase-3 activity follows granzyme B activity with a delay of about 6 minutes. Finally, we illustrate the comparison of several different reporters for granzyme A, M, K and H. The here presented approach is a valuable means for the investigation of the temporal evolution of cell death mediated by cytotoxic lymphocytes.

immunology↗