Effector Molecules Research Articles

Toxoplasma gondii infection induces early host cell cycle arrest and DNA damage in primary human host cells by a MYR1-dependent mechanism

Toxoplasma gondii, an obligate intracellular parasite, control its host cell cycle through mechanisms that are not fully understood. Key effector molecules, including MYR1 and HCE1, play roles in translocating parasite proteins and inducing host cellular cyclin E1 overexpression, respectively. We investigated the early role of MYR1- and HCE1-driven host cell cycle arrest and DNA damage (up to 3 h p.i.). Our findings showed that T. gondii-infected cells experienced S-phase arrest and displayed double-strand DNA breaks as soon as 15 min p.i. This condition persisted until 3 h p.i., at which point we also observed increased host cell binucleation and micronuclei formation, both hallmarks of genomic instability. Furthermore, host cells responded to DNA damage by activating the ATM branch of the homologous recombination repair pathway. MYR1 was shown to be crucial, as TgΔmyr1 tachyzoites failed to induce S-phase arrest and DNA damage foci. In contrast, the absence of HCE1 did not produce these effects, suggesting that cyclin E1 expression was not involved. Also, DNA damage was demonstrated to be ROS-independent, suggesting that ROS did not trigger DNA damage. Our results suggest that T. gondii compromises host cellular DNA integrity depending on MYR1 shortly after infection, maintaining it over time.

Activation of the tick Toll pathway to control infection of Ixodes ricinus by the apicomplexan parasite Babesia microti.

The vector competence of blood-feeding arthropods is influenced by the interaction between pathogens and the immune system of the vector. The Toll and IMD (immune deficiency) signaling pathways play a key role in the regulation of innate immunity in both the Drosophila model and blood-feeding insects. However, in ticks (chelicerates), immune determination for pathogen acquisition and transmission has not yet been fully explored. Here, we have mapped homologs of insect Toll and IMD pathways in the European tick Ixodes ricinus, an important vector of human and animal diseases. We show that most genes of the Toll pathway are well conserved, whereas the IMD pathway has been greatly reduced. We therefore investigated the functions of the individual components of the tick Toll pathway and found that, unlike in Drosophila, it was specifically activated by Gram-negative bacteria. The activation of pathway induced the expression of defensin (defIR), the first identified downstream effector gene of the tick Toll pathway. Borrelia, an atypical bacterium and causative agent of Lyme borreliosis, bypassed Toll-mediated recognition in I. ricinus and also resisted systemic effector molecules when the Toll pathway was activated by silencing its repressor cactus via RNA interference. Babesia, an apicomplexan parasite, also avoided Toll-mediated recognition. Strikingly, unlike Borrelia, the number of Babesia parasites reaching the salivary glands during tick infection was significantly reduced by knocking down cactus. The simultaneous silencing of cactus and dorsal resulted in greater infections and underscored the importance of tick immunity in regulating parasite infections in these important disease vectors.

Functional Analysis of KPvRxLR27, a Novel Plasmopara viticola Effector from a Korean Isolate, and Its Role in Hypersensitive Response.

Plasmopara viticola causes grape downy mildew, one of the most notorious diseases of cultivated grapes that damage vineyards worldwide. The pathogen secretes various effector molecules to infect and modulate the host biological processes. In this study, we aimed to evaluate the roles of KPvRxLR27, an arginine-any amino acid-leucine-arginine (RxLR) effector isolated from P. viticola JN-9 from Jeonju (South Korea) with respect to the reported Bcl-2-associated X and inverted formin1in inducing cell death in non-host Nicotiana benthamiana and resistant grape host cultivars via Agrobacterium-mediated transient transformation. We found that, KPvRxLR27 induced programmed cell death in N. benthamiana and rapid hypersensitive response in resistant grape cultivars. Agroinfiltration assay revealed that putative N-glycosylation at the N186 amino acid sequence and nuclear localization signal motifs at the C-terminus were critical for the effector's cell death-inducing activity of KPvRxLR27. Overexpression assay revealed that KPvRxLR27 was abundantly expressed in the plasma membrane and nuclear regions and activated the accumulation of reactive oxygen species in N. benthamiana. Moreover, KPvRxLR27 expression was significantly delayed in the resistant cultivar than in the susceptible cultivar. Our results suggest KPvRxLR27 as a potential avirulence gene recognized by the host receptors to activate the host immune response-associated genes, providing valuable insights to enhance the pathogen resistance of commercial cultivars.

Post-translational digital data encoding into the genomes of mammalian cell populations.

High resolution cellular signal encoding is critical for better understanding of complex biological phenomena. DNA-based biosignal encoders alter genomic or plasmid DNA in a signal dependent manner. Current approaches involve the signal of interest affecting a DNA edit by interacting with a signal specific promoter which then results in expression of the effector molecule (DNA altering enzyme). Here, we present the proof of concept of a biosignal encoding system where the enzyme terminal deoxynucleotidyl transferase (TdT) acts as the effector molecule upon directly interacting with the signal of interest. A template independent DNA polymerase (DNAp), TdT incorporates nucleotides at the 3' OH ends of DNA substrate in a signal dependent manner. By employing CRISPR-Cas9 to create double stranded breaks in genomic DNA, we make 3'OH ends available to act as substrate for TdT. We show that this system can successfully resolve and encode different concentrations of various biosignals into the genomic DNA of HEK-293T cells. Finally, we develop a simple encoding scheme associated with the tested biosignals and encode the message "HELLO WORLD" into the genomic DNA of HEK-293T cells at a population level with 91% accuracy. This work demonstrates a simple and engineerable system that can reliably store local biosignal information into the genomes of mammalian cell populations.

The Sdp-SH3b2 domain contained in Lactobacillus johnsonii N6.2-derived extracellular vesicles inhibit murine norovirus replication.

The internalization of Lactobacillus johnsonii N6.2 extracellular vesicles (EVs) by cells results in a significant induction of the 2',5'-oligoadenylate synthetase (OAS) pathway. It also induces expression of IFI44L, MX1, MX2 and DDX60. In this work, we evaluated whether the antiviral response induced by L. johnsonii N6.2-derived EVs, has an inhibitory effect on an RNA viral insult using murine norovirus (MNV-1) as the viral infection model. We found that RAW 264.7 Macrophages treated with EVs significantly decreased the levels of MNV-1 genome. These results were consistent with an increase in expression of Oas1b, Oas2, Oasl, Mx1, Mx2 and Ifi44l (6 hours post infection). Out of six proteins enriched in EVs, we found that SH3b2 domain of Sdp was the only protein effector molecule able to recapitulate the activation of the OAS pathway. In C57BL6 mice, the administration of live L. johnsonii N6.2, EVs, and Sdp-SH3b2/liposomes significantly decreased MNV-1 titers in the distal ileum, in contrast to the controls with PBS and liposomes alone that did not affect MNV-1. These results establish that the SH3b2 domain of Sdp, which is enriched in L. johnsonii derived EVs, is an effector molecule in EVs that can orchestrate the control of viral infections in vivo.

Stressor-Actuated Proximity Labeling for Reporting Cellular Interaction.

Cell-cell interactions determine the activation state and function of cells. When host cells are exposed to stressors such as microorganisms, immune defense machinery is activated to release H2O2, providing direct evidence of the relevant cellular physiological processes. Inspired by the fact that peroxidase can catalyze proximity labeling in the presence of exogenous H2O2, a stressor-actuated proximity labeling (SAPL) strategy is developed to report the process information on cell-cell interactions by recording stress levels. The stressors are covalently modified with horseradish peroxidase (HRP) and the H2O2 released by the host cells in response to the stressors triggers HRP-based proximity labeling. Using a fungal mimic or live fungi as stressors, the stress levels of different host cells are compared by in situ imaging of the labeling signals. The ability to accumulate stress signals allows SAPL to more sensitively differentiate between interactions involving different macrophage phenotypes. SAPL is also a powerful tool for real-time, in situ monitoring of the effects of surface modifications on cellular interactions. Thus, the SAPL strategy represents a new perspective in the monitoring of cell-cell interactions using endogenous effector molecules.

GrB-Fc-KS49, an anti-EMP2 granzyme B fusion protein therapeutic alters immune cell infiltration and suppresses breast cancer growth

BackgroundGranzyme B (GrB) is a key effector molecule, delivered by cytotoxic T lymphocytes and natural killer cells during immune surveillance to induce cell death. Fusion proteins and immunoconjugates represent an...

Integrating T-cell inflammation features for prognosis in hepatocellular carcinoma: a novel predictive model.

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death globally and accounts for 75% to 90% of primary liver cancer cases. The high mortality rate of HCC, coupled with the absence of reliable prognostic biomarkers, makes its treatment and prognosis evaluation challenging. The features of the T cell-inflamed microenvironment include active interferon (IFN)-γ signaling and the presence of cytotoxic effector molecules, antigen presentation, and T-cell activating cytokines. Although these features are closely associated with anticancer immunity, their specific roles in HCC remain unclear. This study aimed to investigate the role and prognostic significance of T-cell inflammation (TCI) in HCC patients, providing new insights for clinical diagnosis and treatment strategies. We integrated single-sample gene set enrichment analysis (ssGSEA) and weighted gene coexpression network analysis (WGCNA) to identify the genes associated with TCI at both the single-cell and bulk-transcriptome levels. The HCC TCI-related score (HTCIRS) was developed and assessed with 10 different machine learning algorithms and their combinations, which was followed by validation of the key gene KLF2 in clinical samples and tissue microarrays (TMAs). We identified 65 genes associated with TCI, of which 36 were significantly correlated with overall survival (OS). The HTCIRS demonstrated excellent performance in prognostic prediction, revealing differences in biological functions and immune cell infiltration between different risk groups within the tumor microenvironment (TME). Furthermore, KLF2 was identified to be linked to the prognosis of patients with HCC. The TCI-related score proposed in this study serves as an important tool for prognostic prediction and personalized treatment of patients with HCC, with KLF2 emerging as a potential biomarker for predicting the prognosis of patients with HCC.

Convergence of plant sterols and host eukaryotic cell-derived defensive lipids at the infectious pathogen-host interface.

Plant sterols (PSs) exhibit intrinsic functions such as antibacterial effects. Their effects simultaneously on both host-mediated and bacteria-mediated pathogenesis are not yet fully understood. We hypothesized that when absorptive cells, defensive cells and detoxer cells are cultured together, their convergent response to an infectious pathogen depends on the molecular mimicry between the ingested sterols and their own defensive lipids. A human triple cell co-culture model incorporating colonocytes, macrophages, and hepatocytes was established. Cocultures were stimulated with Klebsiella pneumoniae 52145 (Kp52145) in the presence of pure plant sterol (β-sitosterol, PS) for 6h. Changes in the structural health markers of the stimulated cocultured cells and their immune response and biochemical markers of pathogenicity were determined. PS significantly inhibited the secretion of cytokines induced by Kp52145. Cell viability was higher in the Kp52145+PS group compared to the Kp52145 alone group. PS decreased Kp52145-induced marker of pathogenicity (SOD), accompanied by reduced levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), mannose binding lectin (MBL), and pentraxin 3 (PTX3) which are the mediators and enzymes associated with the inflammatory response to an infectious-inflamed milieu. PS recovered Kp52145-decreased peroxidase (POX), catalase (CAT), complement component 3 (C3), and high-density lipoprotein cholesterol (HDL-C) values. Convergence of ingested plant sterols and host eukaryotic cell-derived defensive lipids mitigates the disruptive effects of bacterial toxic effector molecules. Structural or immunological similarities (molecular mimicry) between ingested plant sterols and host defensive lipids play an important role in modulating bacterial signalling that occurs at the pathogen-host interface and in the mitigation of infection- and inflammation-driven pathological processes.

Hypoimmunogenic CD19 CAR-NK cells derived from embryonic stem cells suppress the progression of human B-cell malignancies in xenograft animals.

Chimeric antigen receptor (CAR) engineered natural killer (NK) cells exhibit advantages such as MHC-independent recognition and strong anti-tumor functions. However, allogeneic CAR-NK cells derived from human tissues are heterogeneous and susceptible to clearance by hosts. We generated a B2M knockout, HLA-E and CD19 CAR ectopic expressing embryonic stem cell (ESC) line, which differentiated normally and gave rise to homogeneous CD19 CAR-NK (CD19 CAR-UiNK) cells using an organoid aggregate induction method. The CD19 CAR-UiNK were co-cultured with T cells or NK cells derived from peripheral blood mononuclear cells (PBMC) with the mismatched HLA to evaluate the immunogenicity of CD19 CAR-UiNK cells. We further assessed the therapeutic effects of CD19 CAR-UiNK cells on CD19+ tumor cells through in vitro cytotoxicity assays and in vivo animal models. The CD19 CAR-UiNK cells exhibited typical expression patterns of activating and inhibitory receptors, and crucial effector molecules of NK cells, similar to those of unmodified NK cells. In co-culture assays, the CD19 CAR-UiNK cells evaded allogeneic T cell response and suppressed allogeneic NK cell response. Functionally, the CD19 CAR-UiNK cells robustly secreted IFN-γ and TNF-α, and upregulated CD107a upon stimulation with Nalm-6 tumor cells. The CD19 CAR-UiNK cells effectively eliminated CD19+ tumor cells in vitro, including B-cell cancer cell lines and primary tumor cells from human B-cell leukemia and lymphoma. Further, the CD19 CAR-UiNK cells exhibited strong anti-tumor activity in xenograft animals. We offer a strategy for deriving homogeneous and hypoimmunogenic CD19 CAR-iNK cells with robust anti-tumor effects from ESCs. Our study has significant implications for developing hypoimmunogenic CD19 CAR-NK cell therapy using human ESC as an unlimited cell source.

The HSP90 Inhibitor Pimitespib Targets Regulatory T Cells in the Tumor Microenvironment.

Regulatory T (Treg) cells play key roles in cancer immunity by suppressing a range of antitumor immune responses and contributing to resistance to programmed death (PD)-1 blockade therapy. Given their critical roles in self-tolerance, local control of immunosuppression by Treg cells, such as in the tumor microenvironment (TME), has been intensively studied. Inhibition of heat shock protein 90 (HSP90), a chaperone with vital roles in regulating proteostasis in cancer cells, impedes cancer progression by interrupting oncogenic signaling pathways and potentially modulating antitumor immunity, but we have very little mechanistic insight into these immune modulatory effects. Here, we show that the number of Treg cells are selectively reduced by the HSP90 inhibitor pimitespib in animal models and patients with gastric cancer in a clinical trial (EPOC1704). Pimitespib reduced the highly immunosuppressive human FOXP3high effector Treg cells by inhibiting their proliferation and decreasing their expression of effector molecules, which improved the priming and activation of antigen-specific CD8+ T cells. Mechanistic studies revealed that pimitespib selectively degraded STAT5, a key transducer of the IL-2 signaling pathway, which is essential for Treg cell development and maintenance, and consequently compromised FOXP3 expression, leading to selective impairment of immunosuppression in the TME by Treg cells. Thus, pimitespib treatment combined with PD-1 blockade exhibited a far stronger antitumor effect than either treatment alone in animal models. Through these data, we propose that HSP90 inhibition is a promising therapeutic option for Treg cell-targeted cancer immunotherapy.

Exploring the Influence of Genetic Single-Nucleotide Polymorphism (SNPs) on Endodontic Pathologies: A Comprehensive Review.

A considerable portion of the global population is affected by pulpitis and periapical lesions. While the impact of infections caused by various microbes and host effector molecules in pulpal and periapical diseases is widely recognized, disease susceptibility and progression are also influenced by the dynamic interaction between host genetic factors and environmental influences. Apical periodontitis occurs as an inflammatory response to microorganisms present in the root canals of infected teeth. Initially functioning as the body's defense mechanism, this response often progresses to chronic inflammation. Several studies have established associations between genetic polymorphisms and various dental conditions, including temporomandibular joint (TMJ) disorders, dental caries, orthognathic surgeries, open bite malocclusion, periapical periodontitis, pulp stones, pulpitis, periapical abscesses, local anesthesia complications, and endodontic treatment outcomes. Key findings from this review highlight the role of specific single-nucleotide polymorphisms (SNPs) in genes such as matrix metalloproteinase (MMP)1, MMP2, MMP3, interleukin (IL)-1β, IL-6, IL-17, and tumor necrosis factor-alpha (TNF-α), which influence inflammatory pathways and tissue remodeling. For example, SNPs in interleukin genes, such as IL-1β (-511 C/T), have been linked to an increased risk of apical periodontitis, while MMP gene polymorphisms contribute to tissue degradation in periapical lesions. This review underscores the importance of identifying genetic markers that drive disease progression and inflammatory processes in pulpal and periapical pathologies. A better understanding of these mechanisms can inform strategies for disease prevention, personalized treatment approaches, and improved endodontic outcomes.

Immune stimulation by inactivated Vibrio splendidus promotes the development and resistance of oyster Crassostrea gigas larvae

The oyster Crassostrea gigas larvae in embryonic development stage have been suffering high mortality rate during hatching, which have seriously hindered the sustainable development of oyster seedling industry. This study explored the immune protection and developmental effects of priming with inactivated Vibrio splendidus in oyster larvae at middle umbo stage (10 d post fertilization, dpf). The results showed that the immune system of umbo larvae was activated after pre-immune stimulation with inactivated V. splendidus. The expressions of immune recognition receptors (CTL-3, Integrin β-1, TLR4), NF-kB signaling component (IKK), effector molecules (IL17-5, Defh2, HSP70) were significantly up-regulated, and the activities of antioxidant enzymes (superoxide dismutase and catalase), hydrolytic enzyme (lysozyme) also increased significantly. The proteins from the stimulated umbo larvae have obvious characteristics of agglutination and inhibition of V. splendidus growth. When the larvae at late umbo (18 dpf) or pediveliger stage (21 dpf) were challenged by live V. splendidus, much lower death rate was observed in the stimulation group compared to the control group. Simultaneously, the expressions of above immune related genes and the activities of antioxidant enzymes were all rapidly up-regulated in pediveliger larvae of immune stimulated group. Moreover, the significantly increased shell height and shell length as well as accelerated development rate, and higher settlement rate were revealed after the umbo larvae are stimulated by inactivated Vibrio splendidus. In summary, inactivated V. splendidus stimulation in oyster umbo larvae could activate their immune system, enhance their resistance against V. splendidus infection till to pediveliger stage, and promote their following growth and development. All the results provided a theoretical basis for solving poor disease resistance and high mortality of larvae in oyster seedling industry.

Development of a Limosilactobacillus reuteri therapeutic delivery platform with reduced colonization potential.

Bacterial biotherapeutic delivery vehicles have the potential to treat a variety of diseases. This approach obviates the need to purify the recombinant effector molecule, allows delivery of therapeutics in situ via oral or intranasal administration, and protects the effector molecule during gastrointestinal transit. Lactic acid bacteria have been broadly developed as therapeutic delivery vehicles though risks associated with the colonization of a genetically modified microorganism have so-far not been addressed. Here, we present an engineered Limosilactobacillus reuteri strain with reduced colonization potential. We applied a dual-recombineering scheme for efficient barcoding and generated mutants in genes encoding five previously characterized and four uncharacterized putative adhesins. Compared with the wild type, none of the mutants were reduced in their ability to survive gastrointestinal transit in mice. CmbA was identified as a key protein in L. reuteri adhesion to HT-29 and enteroid cells. The nonuple mutant, a single strain with all nine genes encoding adhesins inactivated, had reduced capacity to adhere to enteroid monolayers. The nonuple mutant producing murine IFN-β was equally effective as its wild-type counterpart in mitigating radiation toxicity in mice. Thus, this work established a novel therapeutic delivery platform that lays a foundation for its application in other microbial therapeutic delivery candidates and furthers the progress of the L. reuteri delivery system towards human use.IMPORTANCEOne major advantage to leverage gut microbes that have co-evolved with the vertebrate host is that evolution already has taken care of the difficult task to optimize survival within a complex ecosystem. The availability of the ecological niche will support colonization. However, long-term colonization of a recombinant microbe may not be desirable. Therefore, strategies need to be developed to overcome this potential safety concern. In this work, we developed a single strain in which we inactivated the encoding sortase, and eight genes encoding characterized/putative adhesins. Each individual mutant was characterized for growth and adhesion to epithelial cells. On enteroid cells, the nonuple mutant has a reduced adhesion potential compared with the wild-type strain. In a model of total-body irradiation, the nonuple strain engineered to release murine interferon-β performed comparable to a derivative of the wild-type strain that releases interferon-β. This work is an important step toward the application of recombinant L. reuteri in humans.

The intestinal microbiome and Cetobacterium somerae inhibit viral infection through TLR2-type I IFN signaling axis in zebrafish

BackgroundEvidence has accumulated to demonstrate that intestinal microbiome can inhibit viral infection. However, our knowledge of the signaling pathways and identity of specific commensal microbes that mediate the antiviral response is limited. Zebrafish have emerged as a powerful animal model for study of vertebrate-microbiota interactions. Here, a rhabdoviral infection model in zebrafish allows us to investigate the modes of action of microbiome-mediated antiviral effect.ResultsWe observed that oral antibiotics-treated and germ-free zebrafish exhibited greater spring viremia of carp virus (SVCV) infection. Mechanistically, depletion of the intestinal microbiome alters TLR2-Myd88 signaling and blunts neutrophil response and type I interferon (IFN) antiviral innate immunity. Through 16S rRNA sequencing of the intestinal contents from control and antibiotic(s)-treated fish, we identified a single commensal bacterial species, Cetobacterium somerae, that can restore the TLR2- and neutrophil-dependent type I IFN response to restrict SVCV infection in gnotobiotic zebrafish. Furthermore, we found that C. somerae exopolysaccharides (CsEPS) was the effector molecule that engaged TLR2 to mediate the type I IFN-dependent antiviral function.ConclusionsTogether, our results suggest a conserved role of intestinal microbiome in regulating type I IFN antiviral response among vertebrates and reveal that the intestinal microbiome inhibits viral infection through a CsEPS-TLR2-type I IFN signaling axis in zebrafish.7E-apxbKV4cu6qTqgWcuKAVideo

Angiotensin II Induces Vascular Endothelial Dysfunction by Promoting Lipid Peroxidation-Mediated Ferroptosis via CD36.

Angiotensin II (Ang II) is an effective vasoconstriction peptide, a major effector molecule of the renin-angiotensin-aldosterone system (RAAS) and one of the important causes of endothelial dysfunction. Ferroptosis is considered to be involved in the occurrence and development of cardiovascular diseases. This study is dedicated to exploring the role and mechanism of Ang II-induced ferroptosis in HUVECs and to finding molecular targets for vascular endothelial injury and dysfunction during the progression of hypertension. In this study, we found that with the increase in exposure concentration, the intracellular ROS content and apoptosis rate increased significantly, the NO release decreased significantly in the medium- and high-concentration groups and the ET-1 content in the high-concentration group increased significantly. The expression of ZO-1 protein was significantly decreased in the high-concentration group. The expression of p-eNOS, VE-cadherin and Occludin protein showed a dose-dependent downward trend, while the ICAM-1 protein showed an upward trend. Ang II caused lipid metabolism disorders in HUVECs, and the PL-PUFAs associated with ferroptosis were significantly increased. In addition, Ang II promoted a significant increase in intracellular free Fe2+ content and MDA and a significant decrease in GSH content. Furthermore, the expression of GPX4, SLC7A11 and SLC3A2 was down-regulated, the expression of ACSL4, LPCAT3 and ALOX15 was up-regulated, and the ratio of p-cPLA2/cPLA2 was increased. After the intervention of ferroptosis inhibitor Fer-1, the injury and dysfunction of HUVECs induced by Ang II were significantly rescued. Immunofluorescence results showed that the expression of CD36 showed a significant increasing trend and was localized in the cytoplasm. Over-expression of CD36 promoted Ang II-induced ferroptosis and endothelial dysfunction. In conclusion, Ang II induces the injury of HUVECs, decreases vascular diastole and endothelial barrier-related molecules, and increases vascular constriction and adhesion-related molecules, which may be related to CD36 and its mediated lipid peroxidation and ferroptosis signals.

Catalpol regulates apoptosis and proliferation of endothelial cell via activating HIF-1α/VEGF signaling pathway

Burn injuries, especially severe ones, causes microcirculation disorders in local wounds and distant tissues, leading to ischemia and hypoxia of body tissues and organs. The key to prevent and treat complications and improve prognosis after burns is to improve the state of ischemia and hypoxia of tissue and restore the blood supply of organs. Catalpol is an iridoid glycoside compound isolated from Rehmannia radix, which has been widely reported to have various of functions, including antioxidative stress, anti-inflammation, anti-apoptosis, and neuroprotection. However, the pharmacologic action and underlying mechanism of Catalpol in angiogenesis after burn injury remains unclear. The study investigated whether Catalpol regulates apoptosis and proliferation following vascular injury induced by burns using an in vitro model of oxygen-glucose deprivation (OGD) with a human umbilical vein endothelial (HUVE) cell line. The results showed that treatment with Catalpol reduces the level of apoptosis and promotes proliferation of endothelial cell. Mechanistically, Catalpol increases the expression of vascular endothelial growth factor (VEGF) by activating Hypoxia-inducible factor-1α (Hif-1α), resulting in increased expression of related downstream effector molecules. The current study suggested that Catalpol is a promising compound for endothelial protection in burns. It may be an efficient Hif-1α activator for endothelial cell deprived of oxygen and glucose.

Comparison of retinol binding protein 1 with cone specific G-protein as putative effector molecules in cryptochrome signalling

Vision and magnetoreception in navigating songbirds are strongly connected as recent findings link a light dependent radical-pair mechanism in cryptochrome proteins to signalling pathways in cone photoreceptor cells. A previous yeast-two-hybrid screening approach identified six putative candidate proteins showing binding to cryptochrome type 4a. So far, only the interaction of the cone specific G-protein transducin α-subunit was investigated in more detail. In the present study, we compare the binding features of the G-protein α-subunit with those of another candidate from the yeast-two-hybrid screen, cellular retinol binding protein. Purified recombinant European robin retinol binding protein bound retinol with high affinity, displaying an EC50 of less than 5 nM, thereby demonstrating its functional state. We applied surface plasmon resonance and a Förster resonance transfer analysis to test for interactions between retinol binding protein and cryptochrome 4a. In the absence of retinol, we observed no robust binding events, which contrasts the strong interaction we observed between cryptochrome 4a and the G-protein α-subunit. We conclude that retinol binding protein is unlikely to be involved in the primary magnetosensory signalling cascade.

Exopolysaccharides from Bifidobacterium longum subsp. infantis and Bifidobacterium adolescentis modulate Toll-like receptor signaling

BackgroundExopolysaccharides (EPS) from probiotic bacteria like bifidobacteria, have gained considerable attention for the beneficial effects they exert in the gastrointestinal environment. Here, we investigated whether EPS isolated from Bifidobacterium longum subsp. infantis and Bifidobacterium adolescentis can interact with Toll-like receptors (TLRs) in a structure-dependent way and subsequently we investigated whether they influence cytokine-production in dendritic cells (DCs). ResultsEPS from both B. infantis and B. adolescentis were found to be structurally different and were able to inhibit signaling of TLR2 and TLR4 in an EPS-type dependent fashion. EPS from B. infantis was shown to have stronger inhibitory effects on TLR2/1, whereas EPS from B. adolescentis showed stronger effects for TLR2/6 and TLR4. Incubation of DCs with EPS alone had no effect, however stimulation of DCs with spend-medium of epithelial cells incubated with EPS reduced production of the cytokines MCP-1/CCL2 and TNFα. ConclusionHere we show that EPS from B. infantis and B. adolescentis have structure-dependent immunomodulatory effects, indicating that EPS might be important effector molecules responsible for the health benefits of bifidobacteria.

FOXA1 enhances antitumor immunity via repressing interferon-induced PD-L1 expression in nasopharyngeal carcinoma

BackgroundNasopharyngeal carcinoma (NPC) is a distinct subtype of head and neck cancer which is prevalent in south of China and southeastern of Asia. Consistent activation of interferon (IFN) signaling, and...