Pleiotropic action of CpG-ODN on endothelium and macrophages attenuates angiogenesis through distinct pathways

Exploring the impact of oral bacteria remnants on stem cells from the Apical papilla: mineralization potential and inflammatory response

Introduction

Bacterial persistence is considered one of the main causal factors for regenerative endodontic treatment (RET) failure in immature permanent teeth. This interference is claimed to be caused by the interaction of bacteria that reside in the root canal with the stem cells that are one of the essentials for RET. The aim of the study was to investigate whether prolonged exposure of stem cells from the apical papilla (SCAP) to bacterial remnants of Fusobacterium nucleatum, Actinomyces gerensceriae, Slackia exigua, Enterococcus faecalis, Peptostreptococcaceae yurii, commonly found in infected traumatized root canals, and the probiotic bacteria Lactobacillus gasseri and Limosilactobacillus reuteri, can alter SCAP's inflammatory response and mineralization potential.

Methods

To assess the effect of bacterial remnants on SCAP, we used UV-C-inactivated bacteria (as cell wall-associated virulence factors) and bacterial DNA. Histochemical staining using Osteoimage Mineralization Assay and Alizarin Red analysis was performed to study SCAP mineralization, while inflammatory and osteo/odontogenic-related responses of SCAPs were assessed with Multiplex ELISA.

Results

We showed that mineralization promotion was greater with UV C-inactivated bacteria compared to bacterial DNA. Immunofluorescence analysis detected that the early mineralization marker alkaline phosphatase (ALP) was increased by the level of E. coli lipopolysaccharide (LPS) positive control in the case of UV-C-inactivated bacteria; meanwhile, DNA treatment decreased the level of ALP compared to the positive control. SCAP's secretome assessed with Multiplex ELISA showed the upregulation of pro-inflammatory factors IL-6, IL-8, GM-CSF, IL-1b, neurotrophic factor BDNF, and angiogenic factor VEGF, induced by UV-C-killed bacteria.

Discussion

The results suggest that long term stimulation (for 21 days) of SCAP with UV-C-inactivated bacteria stimulate their mineralization and inflammatory response, while DNA influence has no such effect, which opens up new ideas about the nature of RET failure.

Association of Single Nucleotide Polymorphisms from Angiogenesis-Related Genes, ANGPT2, TLR2 and TLR9, with Spontaneous Preterm Labor

In this study, we hypothesized that the changes localized at angiopoietin-2 (ANGPT2), granulocyte-macrophage colony-stimulating factor (CSF2), fms-related tyrosine kinase 1 (FLT1) and toll-like receptor (TLR) 2, TLR6 and TLR9 genes were associated with spontaneous preterm labor (PTL), as well as with possible genetic alterations on PTL-related coagulation. This case-control genetic association study aimed to identify single nucleotide polymorphisms (SNPs) for the aforementioned genes, which are correlated with genetic risk or protection against PTL in Polish women. The study was conducted in 320 patients treated between 2016 and 2020, including 160 women with PTL and 160 term controls in labor. We found that ANGPT2 rs3020221 AA homozygotes were significantly less common in PTL cases than in controls, especially after adjusting for activated partial thromboplastin time (APTT) and platelet (PLT) parameters. TC heterozygotes for TLR2 rs3804099 were associated with PTL after correcting for anemia, vaginal bleeding, and history of threatened miscarriage or PTL. TC and CC genotypes in TLR9 rs187084 were significantly less common in women with PTL, compared to the controls, after adjusting for bleeding and gestational diabetes. For the first time, it was shown that three polymorphisms-ANGPT2 rs3020221, TLR2 rs3804099 and TLR9 rs187084 -were significantly associated with PTL, adjusted by pregnancy development influencing factors.

TLR9 agonist suppresses choroidal neovascularization by restricting endothelial cell motility via ERK/c-Jun pathway

INTRODUCTION

Choroidal neovascularization (CNV) is the feature of neovascular age-related macular degeneration (AMD). It has been demonstrated that inflammation plays a key role in the development of CNV. Here we aim to investigate how TLR9 agonist (CpG-ODN), one of the key regulators of inflammatory responses, suppresses CNV in vivo.

MATERIALS AND METHODS

The cell viability was assessed by MTT and EdU test after CpG-ODN treatment. Endothelial cells gap assay, tube formation assay and transwell assay were practiced to observe how CpG-ODN affected the endothelial cells functions. The choroidal explants and laser-induced CNV model were built to investigate how CpG-ODN suppressed angiogenesis. The ERK and c-Jun expression were evaluated to assess if CpG-ODN affected cell proliferation. Flow cytometry and qPCR was practiced to observe how CpG-ODN regulated cell proliferation.

RESULTS

Our data showed that CpG-ODN not only reduced CNV area in vivo, but also decreased the RPE damage. CpG-ODN inhibited endothelial cells from migration and forming tubes, while the effect was not toxic. EdU test and MTT test suggested that CpG-ODN inhibited endothelial cells proliferation. CpG-ODN significantly increased protein expression of phosphorylated c-Jun but reduced phosphorylated ERK in HUVECs, which was confirmed in ERK transfected 293T cells. JNK inhibitor abolished the suppression of endothelial cells migration and tube formation by CpG-ODN. The findings were also in agreement with the observation in CpG-ODN treated CNV eyes in vivo. The flow cytometry and qPCR data revealed that the suppression of cell motility by CpG-ODN was achieved by arresting endothelial cells cell cycle at G0/G1 phase.

CONCLUSIONS

Our study demonstrated that CpG-ODN suppressed endothelial cell motility by restricting the cell cycle progression at G0/G1 phase, the effect of which was achieved by interacting with ERK/c-Jun pathways.

Macrophage-derived implantable vaccine prevents postsurgical tumor recurrence

Immunotherapy emerges as a potential therapeutic strategy against tumor relapse. However, immunosuppressive tumor microenvironment poses an obstacle to immunotherapy. Of particular note is that macrophages are abundant in solid tumors and tumor-associated macrophages (TAMs) are mainly anti-inflammatory and protumoral. Therefore, re-educating TAMs will be critical for improving the antitumor efficacy of immunotherapy. Herein we engineered a macrophage-derived implantable vaccine for suppressing postsurgical tumor relapse. The vaccine comprised hybrid cytomembranes from macrophages/tumor cells and an immunoadjuvant, cytosinephosphate-guanosine oligodeoxynucleotides (CpG ODNs). The vaccine was further embedded into a calcium alginate hydrogel for tissue-localized delivery. Results show that the vaccine could induce the shift from anti-inflammatory M2-like TAMs to proinflammatory M1-like macrophage. Moreover, the vaccine stimulated systemic immunity by facilitating dendritic cells (DCs) maturation and memory T (T EM) cell activation, forming a self-replenishing circulation in tumor microenvironment. Consequently, the vaccine could prevent the postsurgical tumor relapse at both the primary and distant tumor sites. In addition, the lung metastasis was also reduced by the vaccine implantation in mice. The multifunctional vaccine prepared from biomacromolecule and nature-derived material provides a biocompatible and versatile tool for re-educating TAMs and preventing postsurgical tumor recurrence.

Immune cell shuttle for precise delivery of nanotherapeutics for heart disease and cancer

The delivery of therapeutics through the circulatory system is one of the least arduous and less invasive interventions; however, this approach is hampered by low vascular density or permeability. In this study, by exploiting the ability of monocytes to actively penetrate into diseased sites, we designed aptamer-based lipid nanovectors that actively bind onto the surface of monocytes and are released upon reaching the diseased sites. Our method was thoroughly assessed through treating two of the top causes of death in the world, cardiac ischemia-reperfusion injury and pancreatic ductal adenocarcinoma with or without liver metastasis, and showed a significant increase in survival and healing with no toxicity to the liver and kidneys in either case, indicating the success and ubiquity of our platform. We believe that this system provides a new therapeutic method, which can potentially be adapted to treat a myriad of diseases that involve monocyte recruitment in their pathophysiology.

In Situ Therapeutic Cancer Vaccination with an Oncolytic Virus Expressing Membrane-Tethered IL-2

Successful in situ therapeutic vaccination would allow locally delivered oncolytic virus (OV) to exert systemic immunologic effects on metastases and improve survival. We have utilized bilateral flank tumor models to determine the most efficacious regimens of in situ vaccination. Intratumoral injection with membrane-tethered interleukin -2-armed OV (vvDD-mIL2) plus a Toll-like receptor 9 ligand (CpG) yielded systemic immunization and decreased tumor growth in a contralateral, noninjected tumor. Our main aims were to study the tumor immune microenvironment (TME) after vaccination and identify additional immune adjuvants that may improve the systemic tumor-specific immunity. Immunological profiles in the spleen showed an increased CD8+ T cell/regulatory T cell (Treg) ratio and increased CD11c+ cells after dual injection in one flank tumor. Concurrently, there was increased infiltration of tumor necrosis factor alpha (TNF-α)+CD8+ T cells and interferon gamma (IFN-γ)+CD4+ T cells and reduced CTLA-4+PD-1+CD8+ T cells in the contralateral, noninjected tumor. The anti-tumoral activity depended on CD8+ T cells and IFN-γ, but not CD4+ T cells. Based on the negative immune components still existing in the untreated tumors, we investigated additional adjuvants: clodronate liposome-mediated depletion of macrophages plus anti-PD-1 therapy. This regimen dramatically reduced the tumor burden in the noninjected tumor and increased median survival by 87%, suggesting that inhibition/elimination of suppressive components in the tumor microenvironment (TME) can improve therapeutic outcomes. This study emphasizes the importance of immune profiling to design rational, combined immunotherapy regimens ultimately to impact patient survival.

Exosomal encapsulation of miR-125a-5p inhibited trophoblast cell migration and proliferation by regulating the expression of VEGFA in preeclampsia

This study is aimed to examine the association between umbilical cord blood (UCB) derived exosomal microRNA (miRNA) with preeclampsia (PE) and to further explore the mechanism of a key differential gene (hsa-miR-125a-5p) in preeclampsia. Umbilical cord blood exosomal miRNA(exo-miRNA) from normal pregnant women and pregnant women with preeclampsia was processed via miRNA sequencing. Quantitative real-time polymerase chain reaction (QRT-PCR) was performed to assess the expression of miR-125a-5p in normal and PE placental tissues and peripheral blood derived exosomes in the third trimester. Human trophoblast cell line HTR8/SVneo was assigned as the negative control and miR-125a-5p mimics. QRT-PCR and Western blot were performed to identify the expressions of miR-125a-5p and vascular endothelial growth factor A (VEGFA). CCK8, flow cytometry, wound-healing and Transwell assays were used to analyze the effect of miR-125a-5p on HTR8/SVneo cell migration, proliferation, and cycle distribution. Tube formation was performed to estimate the angiogenesis ability of miR-125a-5p on HUVECs. In conclusion, miR-125a-5p expression in PE placental tissues was higher than in normal subjects, while the expression of VEGFA was lower in PE placental tissues. We then compared the miR-125a-5p mimics group with the negative control group and found that in the mimics group, the cell migration, proliferation and angiogenesis abilities were decreased, and more cells were arrested in the S stage. Our study systematically profiled the UCB exo-miRNA in normal and PE pregnant women and demonstrated that dysregulation of miR-125a-5p might affect HTR8/SVneo cell proliferation and migration and inhibit angiogenesis by regulating VEGFA, indicating that miR-125a-5p is involved in the progression of PE.

Below the surface: The inner lives of TLR4 and TLR9

TLRs are a class of pattern recognition receptors (PRRs) that detect invading microbes by recognizing pathogen-associated molecular patterns (PAMPs). Upon PAMP engagement, TLRs activate a signaling cascade that leads to the production of inflammatory mediators. The localization of TLRs, either on the plasma membrane or in the endolysosomal compartment, has been considered to be a fundamental aspect to determine to which ligands the receptors bind, and which transduction pathways are induced. However, new observations have challenged this view by identifying complex trafficking events that occur upon TLR-ligand binding. These findings have highlighted the central role that endocytosis and receptor trafficking play in the regulation of the innate immune response. Here, we review the TLR4 and TLR9 transduction pathways and the importance of their different subcellular localization during the inflammatory response. Finally, we discuss the implications of TLR9 subcellular localization in autoimmunity.

CD8+ T-Cell Density Imaging with 64Cu-Labeled Cys-Diabody Informs Immunotherapy Protocols

Purpose: Noninvasive and quantitative tracking of CD8+ T cells by PET has emerged as a potential technique to gauge response to immunotherapy. We apply an anti-CD8 cys-diabody, labeled with 64Cu, to assess the sensitivity of PET imaging of normal and diseased tissue.Experimental Design: Radiolabeling of an anti-CD8 cys-diabody (169cDb) with 64Cu was developed. The accumulation of 64Cu-169cDb was evaluated with PET/CT imaging (0, 5, and 24 hours) and biodistribution (24 hours) in wild-type mouse strains (n = 8/group studied with imaging and IHC or flow cytometry) after intravenous administration. Tumor-infiltrating CD8+ T cells in tumor-bearing mice treated with CpG and αPD-1 were quantified and mapped (n = 6-8/group studied with imaging and IHC or flow cytometry).Results: We demonstrate the ability of immunoPET to detect small differences in CD8+ T-cell distribution between mouse strains and across lymphoid tissues, including the intestinal tract of normal mice. In FVB mice bearing a syngeneic HER2-driven model of mammary adenocarcinoma (NDL), 64Cu-169cDb PET imaging accurately visualized and quantified changes in tumor-infiltrating CD8+ T cells in response to immunotherapy. A reduction in the circulation time of the imaging probe followed the development of treatment-related liver and splenic hypertrophy and provided an indication of off-target effects associated with immunotherapy protocols.Conclusions: 64Cu-169cDb imaging can spatially map the distribution of CD8+ T cells in normal organs and tumors. ImmunoPET imaging of tumor-infiltrating cytotoxic CD8+ T cells detected changes in T-cell density resulting from adjuvant and checkpoint immunotherapy protocols in our preclinical evaluation. Clin Cancer Res; 24(20); 4976-87. ©2018 AACR.

Graft versus Host Disease: From Basic Pathogenic Principles to DNA Damage Response and Cellular Senescence

Graft versus host disease (GVHD), a severe immunogenic complication of allogeneic hematopoietic stem cell transplantation (HSCT), represents the most frequent cause of transplant-related mortality (TRM). Despite a huge progress in HSCT techniques and posttransplant care, GVHD remains a significant obstacle in successful HSCT outcome. This review presents a complex summary of GVHD pathogenesis with focus on references considering basic biological processes such as DNA damage response and cellular senescence.

TLR9 (Toll-Like Receptor 9) Agonist Suppresses Angiogenesis by Differentially Regulating VEGFA (Vascular Endothelial Growth Factor A) and sFLT1 (Soluble Vascular Endothelial Growth Factor Receptor 1) in Preeclampsia

Preeclampsia is a common pregnancy-specific disorder characterized by elevated blood pressure and proteinuria. Activation of the maternal immune system and impaired placental angiogenesis are thought to contribute to the pathogenesis of preeclampsia. TLR9 (Toll-like receptor 9) plays a role in innate immunity, defending the organism against infection. The purpose of this study was to determine whether TLR9 inhibits angiogenesis at the fetomaternal interface under conditions of preeclampsia. We confirmed the downregulation of VEGFA (vascular endothelial growth factor A) and upregulation of TLR9 and sFLT1 (soluble vascular endothelial growth factor receptor 1) in placentas from preeclamptic women. Then, we established a mouse model with preeclampsia-like symptoms using the synthetic TLR9 agonist CpG (cytidine-phosphate-guanosine)-ODN (oligodeoxynucleotide; ODN1826). We observed the downregulation of VEGFA and the upregulation of sFLT1 in placentas from the preeclampsia-like animal model and in trophoblasts treated with CpG-ODN (ODN2006). In addition, silencing TLR9 promoted the migration and invasion of HTR8/SVneo cells. In conclusion, TLR9 is capable of robustly suppressing angiogenesis by differentially regulating the expression of VEGFA and sFLT1 at the fetomaternal interface, potentially contributing to the development of preeclampsia.

CpG oligodeoxynucleotide preconditioning improves cardiac function after myocardial infarction via modulation of energy metabolism and angiogenesis

Unmethylated CpG oligodeoxynucleotide (CpG-ODN), a Toll-like receptor 9 (TLR9) ligand, has been shown to protect against myocardial ischemia/reperfusion injury. However, the potential effects of CpG-ODN on myocardial infarction (MI) induced by persistent ischemia remains unclear. Here, we investigated whether and how CpG-ODN preconditioning protects against MI in mice. C57BL/6 mice were treated with CpG-ODN by i.p. injection 2 hr prior to MI induction, and cardiac function, and histology were analyzed 2 weeks after MI. Both 1826-CpG and KSK-CpG preconditioning significantly improved the left ventricular (LV) ejection fraction (LVEF) and LV fractional shortening (LVFS) when compared with non-CpG controls. Histological analysis further confirmed the cardioprotection of CpG-ODN preconditioning. In vitro studies further demonstrated that CpG-ODN preconditioning increases cardiomyocyte survival under hypoxic/ischemic conditions by enhancing stress tolerance through TLR9-mediated inhibition of the SERCA2/ATP and activation of AMPK pathways. Moreover, CpG-ODN preconditioning significantly increased angiogenesis in the infarcted myocardium compared with non-CpG. However, persistent TLR9 activation mediated by lentiviral infection failed to improve cardiac function after MI. Although CpG-ODN preconditioning increased angiogenesis in vitro, both the persistent stimulation of CpG-ODN and stable overexpression of TLR9 suppressed the tube formation of cardiac microvascular endothelial cells. CpG-ODN preconditioning significantly protects cardiac function against MI by suppressing the energy metabolism of cardiomyocytes and promoting angiogenesis. Our data also indicate that CpG-ODN preconditioning may be useful in MI therapy.

The Activation of Human Dermal Microvascular Cells by Poly(I:C), Lipopolysaccharide, Imiquimod, and ODN2395 Is Mediated by the Fli1/FOXO3A Pathway

Endothelial cell (EC) dysfunction has been associated with inflammatory and autoimmune diseases; however, the factors contributing to this dysfunction have not been fully explored. Because activation of TLRs has been implicated in autoimmune diseases, the goal of this study was to determine the effects of TLR ligands on EC function. Human dermal microvascular ECs (HDMECs) treated with TLR3 [Poly(I:C)], TLR4 (LPS), and TLR7 (imiquimod) agonists showed decreased proliferation and a reduced total number of branching tubules in three-dimensional human dermal organoid ex vivo culture. In contrast, the TLR9 ligand class C, ODN2395, increased angiogenesis. The antiproliferative effects of TLR3, TLR4, and TLR7 ligands correlated with significant downregulation of a key regulator of vascular homeostasis, Fli1, whereas TLR9 increased Fli1 levels. Furthermore, Poly(I:C) and LPS induced endothelial to mesenchymal transition that was reversed by the pretreatment with TGF-β neutralizing Ab or re-expression of Fli1. We showed that Fli1 was required for the HDMEC proliferation by transcriptionally repressing FOXO3A. In contrast to TLR9, which suppressed activation of the FOXO3A pathway, TLR3, TLR4, and TLR7 ligands activated FOXO3A as indicated by decreased phosphorylation and increased nuclear accumulation. The inverse correlation between Fli1 and FOXO3A was also observed in the vasculature of scleroderma patients. This work revealed opposing effects of TLR9 and TLR3, TLR4, and TLR7 on the key angiogenic pathways, Fli1 and FOXO3A. Our results provide a mechanistic insight into the regulation of angiogenesis by TLRs and confirm a central role of Fli1 in regulating vascular homeostasis.