Bin Qu

Saarland University | UKS · Fachbereich Biophysik

Effective T cell responses against tumor cells require diverse effector functions including polarization towards tumor cells to form immunological synapses and nuclear factor of activated T-cells (NFAT)-dependent gene transcription. While the role of tumor cell softening has been associated with malignancy, stemness, and metastasis, potentially con...

Natural killer (NK) cells play a vital role in eliminating tumorigenic cells. Efficient locating and killing of target cells in complex three‐dimensional (3D) environments are critical for their functions under physiological conditions. However, the role of mechanosensing in regulating NK‐cell killing efficiency in physiologically relevant scenario...

Our work presents a high-throughput kinetic killing assay in the 3D matrix using high content imaging that is a robust and powerful cytotoxicity assay for evaluating the killing efficiency of immune killer cells or conducting drug screening under physiologically and pathologically relevant scenarios, particularly in the context of solid tumors.

In living therapeutic materials (LTMs), organisms genetically programmed to produce and deliver drugs are encapsulated in porous matrices acting as physical barriers between the therapeutic organisms and the host cells. LTMs consisting of engineered E. coli encapsulated in Pluronic F127-based hydrogels have been frequently used in LTM designs but t...

In vivo, immune killer cells must infiltrate into tissues and search for their cognate target cells in 3D environments. To investigate the cytotoxic function of immune killer cells, there is currently a significant need for an in vitro kinetic assay that resembles 3D in vivo features. Our work presents a high-throughput kinetic killing assay in 3D...

Natural killer (NK) cells play key roles in eliminating pathogen-infected cells. Verbena officinalis (V. officinalis) has been used as a medical plant in traditional and modern medicine for its anti-tumor and anti-inflammatory activities, but its effects on immune responses remain largely elusive. This study aimed to investigate the potential of V....

Natural killer (NK) cells play a vital role in eliminating tumorigenic cells. Efficient locating and killing of target cells in complex three-dimensional (3D) environments is critical for their functions under physiological conditions. Recent studies have shown that NK cell activation is regulated by substrate stiffness. However, the role of mechan...

In living therapeutic materials, organisms genetically programmed to produce and deliver drugs are encapsulated in porous matrices or hydrogels acting as physical barriers between the therapeutic organisms and the host cells. The therapeutic potential of such constructs has been highlighted in in vitro studies, but the translation to in vivo scenar...

Two years after the coronavirus disease 2019 (COVID-19) outbreak, an increasing number of patients continue to suffer from long COVID (LC), persistent symptoms, and/or delayed or long-term complications beyond the initial 4 weeks from the onset of symptoms. Constant fatigue is one of the most common LC symptoms, leading to severely reduced quality...

CD4+ T cells are essential players in orchestrating the specific immune response against intracellular pathogens, and in inhibiting tumor development in an early stage. The activation of T cells is triggered by engagement of T cell receptors (TCRs). Here, CD3 and CD28 molecules are key factors, (co)stimulating signaling pathways essential for activ...

TNF-related apoptosis inducing ligand (TRAIL) is expressed on cytotoxic T lymphocytes (CTLs) and TRAIL is linked to progression of diabetes. However, the impact of high glucose on TRAIL expression and its related killing function in CTLs still remains largely elusive. Here, we report that TRAIL is substantially up-regulated in CTLs in environments...

Visualizing interactions between cells and the extracellular matrix (ECM) mesh is important to understand cell behavior and regulatory mechanisms by the extracellular environment. However, long term visualization of three-dimensional (3D) matrix structures remains challenging mainly due to photobleaching or blind spots perpendicular to the imaging...

Natural killer (NK) cells play a key role in eliminating pathogen-infected cells. Verbena officinalis (V. officinalis) has been used as a medical plant in traditional and modern medicine, exhibiting anti-tumor and anti-inflammation activities, but its roles in immune responses still remains largely elusive. In this work, investigated the regulation...

Visualization cell interaction with the extracellular matrix (ECM) mesh works plays a central role in understanding cell behavior and the corresponding regulatory mechanisms by the environment in vivo. However, long term visualization of 3D matrix structures remains challenging mainly due to photobleaching or blind spot in the currently available a...

Efficacy of cytotoxic T lymphocyte (CTL)-based immunotherapy is still unsatisfactory against solid tumors, which are frequently characterized by condensed extracellular matrix. Here, using a unique 3D killing assay, we identify that the killing efficiency of primary human CTLs is substantially impaired in dense collagen matrices. Although the expre...

Cytotoxic T lymphocytes (CTLs) are involved in development of diabetes. However, the impact of excessive glucose on CTL effector functions remains largely elusive. Here, we report that metabolic processes in CTLs are reprogrammed by high glucose (HG). TNF-related apoptosis inducing ligand (TRAIL) is substantially up-regulated in CTLs in environment...

T cells are activated by target cells via an intimate contact, termed immunological synapse (IS). Cellular mechanical properties, especially stiffness, are essential to regulate cell functions. However, T cell stiffness at a subcellular level at the IS still remains largely elusive. In this work, we established an atomic force microscopy (AFM)-base...

Cytotoxic T lymphocytes (CTLs) are key players to eliminate tumorigenic or pathogen-infected cells using lytic granules (LG) and Fas ligand (FasL) pathways. Depletion of glucose leads to severely impaired cytotoxic function of CTLs. However, the impact of excessive glucose on CTL functions still remains largely unknown. Here we used primary human C...

Progress in our understanding of mechanotransduction events requires noninvasive methods for the manipulation of forces at molecular scale in physiological environments. Inspired by cellular mechanisms for force application (i.e. motor proteins pulling on cytoskeletal fibers), we present a unique molecular machine that can apply forces at cell-matr...

Solid tumors are often characterized by condensed extracellular matrix (ECM). The impact of dense ECM on cytotoxic T lymphocytes (CTL) function is not fully understood. Here, we report that CTL-mediated cytotoxicity is substantially impaired in dense collagen matrices. Although the intrinsic killing machinery including expression of cytotoxic prote...

In saliva and gingival crevicular fluid (GCF) soluble factors such as cytokines, chemokines and growth factors have shown a great potential serving as biomarkers for early detection and/or diagnosis of oral and systemic diseases. However, GCF and saliva, which one is a better source is still under debate. This study aimed to gain an overview of cyt...

In saliva and gingival crevicular fluid (GCF) soluble factors such as cytokines, chemokines and growth factors have shown a great potential serving as biomarkers for early detection and/or diagnosis of oral and systemic diseases. However, GCF and saliva, which one is a better source is still under debate. This study aimed to gain an overview of cyt...

The immune system provides our defense against pathogens and aberrant cells, including tumorigenic and infected cells. Motility is one of the fundamental characteristics that enable immune cells to find invading pathogens, control tissue damage, and eliminate primary developing tumors, even in the absence of external treatments. These processes are...

T cells are activated by cognate target cells via an intimate contact, termed immunological synapse (IS). Cellular mechanical properties, especially stiffness, are essential to regulate cell functions, T cell stiffness at a subcellular level at the IS still remains largely elusive. In this work, we established an atomic force microscopy (AFM)-based...

CD8⁺ cytotoxic T lymphocytes (CTL) and natural killer cells are the main cytotoxic killer cells of the human body to eliminate pathogen-infected or tumorigenic cells (also known as target cells). To find their targets, they have to navigate and migrate through complex biological microenvironments, a key component of which is the extracellular matri...

Delivery of vesicles to their desired destinations plays a central role in maintaining proper cell functionality. In certain scenarios, depending on loaded cargos, the vesicles have spatially distinct destinations. For example, in T cells, some cytokines (e.g., IL-2) are polarized to the T cell-target cell interface, whereas the other cytokines are...

The analysis of T cell responses to mechanical properties of antigen presenting cells (APC) is experimentally challenging at T cell-APC interfaces. Soft hydrogels with adjustable mechanical properties and biofunctionalization are useful reductionist models to address this problem. Here, we report a methodology to fabricate micropatterned soft hydro...

In CTLs: High glucose‐culture enhances thapsigargin‐induced SOCE but decreases target recognition‐induced Ca²⁺ influx. High glucose‐culture regulates expression of ORAIs and STIMs without affecting glucose uptake. More high glucose‐cultured CTLs are prone to necrosis after execution of killing.

The killing efficiency of cytotoxic T lymphocytes (CTLs) is tightly regulated by intracellular Ca2+ concentration. Glucose is the key energy source for CTLs, lack of which significantly impairs CTL activation, proliferation and effector functions. The impact of high glucose on Ca2+ influx in CTLs remains largely elusive. In this work, we stimulated...

Mechanotransduction events in physiological environments are difficult to investigate, in part due to the lack of experimental tools to apply forces to mechanosensitive receptors remotely. Inspired by cellular mechanisms for force application (i.e. motor proteins pulling on cytoskeletal fibers), here we present a unique molecular machine that can a...

To fulfill their killing functions, cytotoxic T lymphocytes (CTLs) need to migrate to search for their target cells in complex biological microenvironments, a key component of which is extracellular matrix (ECM). The mechanisms underlying CTL's navigation are not well understood so far. Here we use a collagen assay as a model for the ECM and analyz...

Significance Dendritic cells are immune cells that migrate within the human body in search of pathogens. This search is performed by a random walk, which combines persistent and diffuse movements. The mechanism underlying this random walk is currently not known. We analyzed very long trajectories of dendritic cells ex vivo, and we describe here the...

In vivo, activation, proliferation, and function of immune cells all occur in a three-dimensional (3D) environment, for instance in lymph nodes or tissues. Up to date, most in vitro systems rely on two-dimensional (2D) surfaces, such as cell-culture plates or coverslips. To optimally mimic physiological conditions in vitro, we utilize a simple 3D c...

Key points: Cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells are required to eliminate cancer cells. We analysed the Ca2+dependence of CTL and NK cell cytotoxicity and found that in particular CTLs have a very low optimum of [Ca2+]i(between 122 and 334 nm) and [Ca2+]o(between 23 and 625 μm) for efficient cancer cell elimination, well b...

The actin-binding protein profilin1 (PFN1) plays a central role in actin dynamics, which is essential for cytotoxic T lymphocyte (CTL) functions. The functional role of PFN1 in CTLs, however still remains elusive. Here, we identify PFN1 as the only member of the profilin family expressed in primary human CD8(+) T cells. Using in vitro assays, we fi...

Natural killer (NK) cells play a central role during innate immune responses by eliminating pathogen-infected or tumorigenic cells. In the microenvironment, NK cells encounter not only target cells but also other cell types including non-target bystander cells. The impact of bystander cells on NK killing efficiency is, however, still elusive. In th...

Breast cancer (BC) is the leading cancer in women worldwide. Changes in DNA methylation in peripheral blood could be associated with malignant diseases. Making use of screening results by llumina 27K Methylation Assay, we validated demethylation of five CpG sites of S100P gene in blood cell DNA of BC patients by three independent retrospective stud...

We consider random search processes alternating stochastically between diffusion and ballistic motion, in which the distribution function of ballistic motion directions varies from point to point in space. The specific space dependence of the directional distribution together with the switching rates between the two modes of motion establishes a sp...

Ca²⁺ microdomains and spatially resolved Ca²⁺ signals are highly relevant for cell function. In T cells, local Ca²⁺ signaling at the immunological synapse (IS) is required for downstream effector functions. We present experimental evidence that the relocation of the MTOC towards the IS during polarization drags mitochondria along with the microtubu...

Cytotoxic T lymphocytes (CTL) eliminate pathogen-infected and cancerous cells mainly by polarized secretion of lytic granules (LG, containing cytotoxic molecules like perforin and granzymes) at the immunological synapse (IS). Members of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) family are involved in traffick...

Breast cancer (BC) is the leading cause of cancer-related mortality in women worldwide. Changes in DNA methylation in peripheral blood could be associated with malignancy at early stage. However, the BC-associated DNA methylation signatures in peripheral blood were largely unknown. Here, we performed a genome-wide methylation screening and identifi...

Natural killer (NK) cells and cytotoxic T lymphocytes (CTLs) are key elements of the cellular immune response and eliminate pathogen-infected and tumorigenic cells [1–3]. Quantification of killer cell-mediated cytotoxicity is of great importance in immunotherapy [4, 5], to predict cancer risk [6] and to improve antibody-based treatments [7–9]. A pr...

The major function of cytotoxic T lymphocytes (CTLs) is to eliminate pathogen-infected and tumorigenic cells. This is mediated mainly through the exocytosis of lytic granules (LGs) containing cytotoxic components, such as perforin and granzymes at the immunological synapse (IS). The soluble NSF attachment receptor (SNARE) protein isoforms are well...

Cytotoxicity is an essential parameter to examine killer cell activity, to screen hits for new drugs, and to proof safety evaluation. Cytotoxicity assays are routinely used in basic research, clinical studies, and industrial applications. However, the most commonly applied standard end-point cytotoxicity assays largely suffer from the lack of kinet...

Cytotoxicity is an essential parameter to examine killer cell activity, to screen hits for new drugs, and to proof safety evaluation. Cytotoxicity assays are routinely used in basic research, clinical studies, and industrial applications. However, the most commonly applied standard end-point cytotoxicity assays largely suffer from the lack of kinet...

The correlation between the loss of Profilin1 (Pfn1) with tumor progression indicated that Pfn1 is a tumor suppressor in human carcinoma. The molecular mechanisms underlying Pfn1 tumor suppression has yet to be elucidated. In this study, we showed that Pfn1 overexpression sensitizes cancer cells to apoptosis through the typical intrinsic apoptotic...

Killing cancer cells by cytotoxic T lymphocytes (CTL) and by natural killer (NK) cells is of vital importance. Cancer cell proliferation and apoptosis depend on the intracellular Ca(2+) concentration, and the expression of numerous ion channels with the ability to control intracellular Ca(2+) concentrations has been correlated with cancer. A rise o...

Calcium (Ca(2+)) influx is required for the activation and function of all cells in the immune system. It is mediated mainly by store-operated Ca(2+) entry (SOCE) through Ca(2+) release-activated Ca(2+) (CRAC) channels located in the plasma membrane. CRAC channels are composed of ORAI proteins that form the channel pore and are activated by stromal...

Cytotoxic T Lymphocytes (CTLs) are activated CD8+ T cells which identify and kill pathogen infected, tumor and nonself cells by FAS ligand expression and by secretion of perforin and granzymes from lytic granules specifically at the immunological synapse (IS). This prevents killing of healthy bystander cells. Therefore at the time of killing these...

The major function of cytotoxic T lymphocytes (CTLs) is to eliminate pathogen-infected and tumorigenic cells. This is mediated mainly through the exocytosis of lytic granules (LGs) containing cytotoxic components, such as perforin and granzymes at the immunological synapse (IS). The soluble NSF attachment receptor (SNARE) protein isoforms are well...

Lytic granule (LG)-mediated apoptosis is the main mechanism by which CTL kill virus-infected and tumorigenic target cells. CTL form a tight junction with the target cells, which is called the immunological synapse (IS). To avoid unwanted killing of neighboring cells, exocytosis of lytic granules (LG) is tightly controlled and restricted to the IS....

Ca(2+) homeostasis controls a diversity of cellular processes including proliferation and apoptosis. A very important aspect of Ca(2+) signaling is how different Ca(2+) signals are translated into specific cell functions. In T cells, Ca(2+) signals are induced following the recognition of antigen by the T cell receptor and depend mainly on Ca(2+) i...

SNARE proteins are essential fusion mediators for many intracellular trafficking events. Here, we investigate the role of Syntaxin7 (Stx7) in the release of lytic granules from cytotoxic T lymphocytes (CTLs). We show that Stx7 is expressed in CTLs and is preferentially localized to the region of lytic granule release, the immunological synapse (IS)...

Store-operated Ca(2+) entry is a major Ca(2+) entry mechanism that is present in most cell types. In immune cells, store-operated Ca(2+) entry is almost exclusively mediated by Ca(2+) release-activated Ca(2+) (CRAC) channels. Ca(2+) entry through these channels and the corresponding cytosolic Ca(2+) signals are required for many immune cell functio...

TCR enrichment and cytotoxic granules accumulation at the immunological synapse are necessary for cytotoxic T lymphocyte-mediated killing. Using immunocytochemistry, confocal microscopy, 4D fast live cell imaging and total internal reflection fluorescence microscopy, we analyzed the localization and transport of recycling TCR vesicles and cytotoxic...

Cytotoxic T lymphocytes (CTLs) exert their cytotoxic activity through the polarized secretion of cytotoxic granules at the immunological synapse (IS). Because soluble NSF attachment receptor (SNARE) proteins mediate numerous intra- and intercellular fusion events and are essential effectors of exocytosis of synaptic granules in neurons, we examined...

Cytotoxic T lymphocytes (CTLs) kill target cells by secretion of cytotoxic components such as perforin and granzymes which are contained in lytic granules. Fusion of lytic granules occurs at the contact zone between the target cell and the CTL, the immunological synapse (IS). T cell receptor (TCR) enrichment at the IS is one of the key early events...

Chromatin modification is considered to be a fundamental mechanism of regulating gene expression to generate coordinated responses to environmental changes, however, whether it could be directly regulated by signals mediated by G protein-coupled receptors (GPCRs), the largest surface receptor family, is not known. Here, we show that stimulation of...

Norepinephrine released by the sympathetic nerve terminals regulates the immune system primarily via its stimulation of beta(2)-adrenergic receptor (beta(2)AR), but the underlying molecular mechanisms remain to be elicited. Beta(2)AR, a well-studied G protein-coupled receptor (GPCR), is functionally regulated by beta-arrestin2, which not only cause...

Norepinephrine released by the sympathetic nerve terminals regulates the immune system primarily via its stimulation of β2-adrenergic receptor (β2AR), but the underlying molecular mechanisms remain to be elicited. β2AR, a well-studied G protein-coupled receptor (GPCR), is functionally regulated by β-arrestin2, which not only causes receptor desensi...

Myf-5, a member of the muscle regulatory factor family of transcription factors, plays an important role in the determination, development, and differentiation of the skeletal muscle. Factors that regulate the expression of myf-5 itself are not well understood. We show here that a T-box binding site in the Xenopus myf-5 promoter mediated the activa...