PdPtB Electrochemiluminescence Nanoenhancer and SiC@Au-PEDOT Nanowires-Based Detection of ß-Amyloid Oligomers in Alzheimer's Disease.

ß-Amyloid oligomers (AßOs) are promising biomarkers for the diagnosis of Alzheimer's disease (AD). The present research introduces a novel electrochemiluminescence (ECL) immunosensor based on PdPtB nanoenhancer and SiC@Au-PEDOT nanowires (NWs) for the specific and ultrasensitive detection of AßOs. The PdPtB nanoenhancer exhibited excellent oxidase-like catalytic activity with in situ generation of reactive oxygen species (ROS) to enhance luminol ECL in neutral media. In addition, SiC@Au-PEDOT NWs were utilized as a biocompatible and conductive substrate for the modification of the glassy carbon electrode (GCE). With this design, the ECL immunosensor showed outstanding AßOs analytical performance without exogenous coreactant. The ECL immunosensor demonstrated a favorable linear range of 20 pM to 20 nM and a detection limit of 10 pM under optimized conditions with potential straightforward clinical application. In general, the developed ECL immunosensor provides a promising strategy for the early diagnosis of AD.

The preprogrammed anti-inflammatory phenotypes of CD11chigh macrophages by Streptococcus pneumoniae aminopeptidase N safeguard from allergic asthma.

BACKGROUND: Early microbial exposure is associate with protective allergic asthma. We have previously demonstrated that Streptococcus pneumoniae aminopeptidase N (PepN), one of the pneumococcal components, inhibits ovalbumin (OVA) -induced airway inflammation in murine models of allergic asthma, but the underlying mechanism was incompletely determined. METHODS: BALB/c mice were pretreated with the PepN protein and exposed intranasally to HDM allergen. The anti-inflammatory mechanisms were investigated using depletion and adoptive transfer experiments as well as transcriptome analysis and isolated lung CD11chigh macrophages. RESULTS: We found pretreatment of mice with PepN promoted the proliferation of lung-resident F4/80+CD11chigh macrophages in situ but also mobilized bone marrow monocytes to infiltrate lung tissue that were then transformed into CD11high macrophages. PepN pre-programmed the macrophages during maturation to an anti-inflammatory phenotype by shaping the metabolic preference for oxidative phosphorylation (OXPHOS) and also inhibited the inflammatory response of macrophages by activating AMP-activated protein kinase. Furthermore, PepN treated macrophages also exhibited high-level costimulatory signaling molecules which directed the differentiation into Treg. CONCLUSION: Our results demonstrated that the expansion of CD11chigh macrophages in lungs and the OXPHOS metabolic bias of macrophages are associated with reduced allergic airway inflammation after PepN exposure, which paves the way for its application in preventing allergic asthma.

Detoxified pneumolysin derivative ΔA146Ply inhibits triple- negative breast cancer metastasis mainly via mannose receptor-mediated autophagy inhibition.

The detoxified pneumolysin derivative ΔA146Ply has been proven to have a direct anti-triple negative breast cancer effect by our group, but its work model remains unclear. In this study, we focused on its ability to inhibit triple-negative breast cancer metastasis. We found that ΔA146Ply suppressed the migration and invasion of triple-negative breast cancer cells by activating mannose receptor and toll-like receptor 4. Their activation triggers the activation of the mammalian target of rapamycin signaling, sequentially leading to autophagy, transforming growth factor-ß1, and epithelial-mesenchymal transition inhibition. Furthermore, the combination of doxorubicin and ΔA146Ply significantly inhibited triple-negative breast cancer progression and prolonged survival in tumor-bearing mice. Taken together, our study provides an alternative microbiome-based mannose receptor-targeted therapy for triple-negative breast cancer and a novel theoretical and experimental basis for the downstream signaling pathway of the mannose receptor.

IL-27 mediates immune response of pneumococcal vaccine SPY1 through Th17 and memory CD4+T cells.

Vaccination is an effective means of preventing pneumococcal disease and SPY1 is a live attenuated pneumococcal vaccine we obtained earlier. We found IL-27 and its specific receptor (WSX-1) were increased in SPY1 vaccinated mice. Bacterial clearance and survival rates were decreased in SPY1 vaccinated IL-27Rα-/- mice. The vaccine-induced Th17 cell response and IgA secretion were also suppressed in IL-27Rα-/- mice. STAT3 and NF-κB signaling and expression of the Th17 cell polarization-related cytokines were also decreased in IL-27Rα-/- bone-marrow-derived dendritic cells(BMDC) stimulated with inactivated SPY1. The numbers of memory CD4+T cells were also decreased in SPY1 vaccinated IL-27Rα-/- mice. These results suggested that IL-27 plays a protective role in SPY1 vaccine by promoting Th17 polarization through STAT3 and NF-κB signaling pathways and memory CD4+T cells production in the SPY1 vaccine. In addition, we found that the immune protection of SPY1 vaccine was independent of aerobic glycolysis.

Protein Kinase CK2 Promotes Proliferation, Abnormal Differentiation, and Proinflammatory Cytokine Production of Keratinocytes via Regulation of STAT3 and Akt Pathways in Psoriasis.

Protein kinase CK2 is a constitutively active and ubiquitously expressed serine/threonine kinase that is closely associated with various types of cancers, autoimmune disorders, and inflammation. However, the role of CK2 in psoriasis remains unknown. Herein, the study indicated elevated expression of CK2 in skin lesions from patients with psoriasis and from psoriasis-like mice. In the psoriasis-like mouse model, the CK2-specific inhibitor CX-4945 ameliorated imiquimod-induced psoriasis symptoms with reduced proliferation, abnormal differentiation, inflammatory cytokine production (especially IL-17A) of keratinocytes, and infiltration of γδ T cells. In in vitro studies, exogenous CK2 promoted hyperproliferation and abnormal differentiation of human keratinocytes, which were reversed by the suppression of CK2 with CX-4945 or siRNA. Furthermore, knockdown of CK2 reduced IL-17A expression and abolished IL-17A-induced proliferation and inflammatory cytokine expression in keratinocytes. Interestingly, IL-17A increased the expression of CK2 in keratinocytes, thereby establishing a positive feedback loop. In addition, suppression of CK2 inhibited the activation of STAT3 and Akt signaling pathways in human keratinocytes and imiquimod-induced psoriatic lesions of mice. These findings indicate that a highly expressed CK2 level in the skin lesions is required in the development of psoriasis by promoting epidermal hyperplasia, abnormal differentiation, and inflammatory response via regulation of the STAT3 and Akt signaling pathways. CK2 may be a target for the treatment of psoriasis.

Progranulin deficiency suppresses allergic asthma and enhances efferocytosis via PPAR-γ/MFG-E8 regulation in macrophages.

Efferocytosis can resolve airway inflammation and enhance airway tolerance in allergic asthma. While previous work has reported that progranulin (PGRN) regulated macrophage efferocytosis, but it is unclear whether PGRN-mediated efferocytosis is associated with asthma. Here, we found that in an ovalbumin (OVA)-induced allergic asthma model, the airway inflammation was suppressed and the apoptosis in lung tissues was ameliorated in PGRN-deficient mice. In contrast, PGRN knockdown in human bronchial epithelial cells increased apoptosis in vitro. Furthermore, PGRN-deficient macrophages had significantly stronger efferocytosis ability than wild type (WT) macrophages both in vitro and in vivo. PGRN-deficient peritoneal macrophages (PMs) exhibited increased expression of genes associated with efferocytosis including milk fat globule-epidermal growth factor 8 (MFG-E8), peroxisome proliferator-activated receptor gamma (PPAR-γ) and sirtuin1 (SIRT1) and increased capacity to produce the anti-inflammatory mediator interleukin (IL)-10 during efferocytosis. GW9662, the inhibitor of PPAR-γ, abolished increased efferocytosis and MFG-E8 expression in PGRN-deficient PMs suggesting that PGRN deficiency enhanced MFG-E8-mediated efferocytosis through PPAR-γ. Correspondingly, efferocytosis genes were increased in the lungs of OVA-induced PGRN-deficient mice. GW9662 treatment reduced MFG-E8 expression but did not significantly affect airway inflammation. Our results demonstrated that PGRN deficiency enhanced efferocytosis via the PPAR-γ/MFG-E8 pathway and this may be one of the reasons PGRN deficiency results in inhibition of airway inflammation in allergic asthma.

CD5L attenuates allergic airway inflammation by expanding CD11chigh alveolar macrophages and inhibiting NLRP3 inflammasome activation via HDAC2.

Allergic asthma is an airway inflammatory disease dominated by type 2 immune responses and there is currently no curative therapy for asthma. CD5-like antigen (CD5L) has been known to be involved in a variety of inflammatory diseases. However, the role of CD5L in allergic asthma remains unclear. In the present study, mice were treated with recombinant CD5L (rCD5L) during house dust mite (HDM) and ovalbumin (OVA) challenge to determine the role of CD5L in allergic asthma, and the underlying mechanism was further explored. Compared with PBS group, serum CD5L levels of asthmatic mice were significantly decreased, and the levels of CD5L in lung tissues and bronchoalveolar lavage fluid (BALF) were significantly increased. CD5L reduced airway inflammation and Th2 immune responses in asthmatic mice. CD5L exerted its anti-inflammatory function by increasing CD11chigh alveolar macrophages (CD11chigh AMs), and the anti-inflammatory role of CD11chigh AMs in allergic asthma was confirmed by CD11chigh AMs depletion and transfer assays. In addition, CD5L increased the CD5L+ macrophages and inhibited NLRP3 inflammasome activation by increasing HDAC2 expression in lung tissues of asthmatic mice. Hence, our study implicates that CD5L has potential usefulness for asthma treatment.

Self-electrochemiluminescence biosensor based on CRISPR/Cas12a and PdCuBP@luminol nanoemitter for highly sensitive detection of cytochrome c oxidase subunit III gene of acute kidney injury.

The cytochrome c oxidase subunit III (COX III) gene is a powerful biomarker for the early diagnosis of acute kidney injury. However, current methods for COX III gene detection are usually laborious and time-consuming, with limited sensitivity. Herein, we report a novel self-electrochemiluminescence (ECL) biosensor for highly sensitive detection of the COX III gene based on CRISPR/Cas12a and nanoemitters of luminol-loaded multicomponent metal-metalloid PdCuBP alloy mesoporous nanoclusters. The nanoemitter with excellent self-ECL in neutral media exhibited a high specific surface area for binding luminol and outstanding oxidase-like catalytic activity toward dissolved O2. Meanwhile, the CRISPR/Cas12a system, as a target-trigger, was employed to specifically recognize the COX III gene and efficiently cleave the interfacial quencher of dopamine-labeled hairpin DNA. As a result, the ECL biosensor showed superior analytical performance for COX III gene detection without exogenous coreactant. Benefiting from the high-efficiency ECL emission of the nanoemitter and Cas12a-mediated interfacial cleavage of the quencher, the developed ECL biosensor exhibited high sensitivity to COX III with a low detection limit of 0.18 pM. The established ECL biosensing method possessed excellent practical performance in urine samples. Meaningfully, the proposed strategy presents promising prospects for nucleic acid detection in the field of clinical diagnostics.

IL-6 Prevents Lung Macrophage Death and Lung Inflammation Injury by Inhibiting GSDME- and GSDMD-Mediated Pyroptosis during Pneumococcal Pneumosepsis.

Streptococcus pneumoniae is a leading bacterial cause of a wide range of infections, and pneumococcal pneumosepsis causes high mortality in hosts infected with antibiotic-resistant strains and those who cannot resolve ongoing inflammation. The factors which influence the development and outcome of pneumosepsis are currently unclear. IL-6 is critical for maintaining immune homeostasis, and we determined that this cytokine is also essential for resisting pneumosepsis, as it inhibits macrophage pyroptosis and pyroptosis-related inflammation injury in the lung. IL-6 affected infection outcomes in mice and exerted a protective role, primarily via macrophages. We further found that IL-6 deficiency led to increased lung macrophage death and aggravated lung inflammation, and that exogenous administration of IL-6 protein could decrease macrophage death and alleviate lung tissue inflammation. IL-6 also protected Streptococcus pneumoniae-induced lung macrophage death and lung inflammation injury by inhibiting gasdermin E (GSDME)- and gasdermin D (GSDMD)-mediated pyroptosis. Together, these data reveal a novel mechanism for the development of pneumosepsis and the critical protective role of IL-6. These findings may assist in the early identification and treatment of pneumococcal pneumosepsis. IMPORTANCE Pneumococcal pneumonia has been a significant cause of morbidity and mortality throughout human history. Failing to control pneumococcal pneumonia and resolve ongoing inflammation in a host can cause sepsis, namely pneumococcal pneumosepsis, and death ensues. Few theories have suggested an optimally therapeutic option for this infectious disease. The interleukin-6 (IL-6, a cytokine featuring pleiotropic activity) theory, proposed here, implies that IL-6 acts as a protector against pneumococcal pneumosepsis. IL-6 prevents lung macrophage death and lung inflammation injury by inhibiting a caspase-3-GSDME-mediated switch from apoptosis to pyroptosis and inhibiting caspase-1-GSDMD-mediated classic pyroptosis during pneumococcal pneumosepsis. Thus, IL-6 is an important determinant for controlling bacterial invasion and a homeostatic coordinator of pneumococcal pneumosepsis. This study clarifies a novel mechanism of occurrence and development of pneumonia and secondary sepsis following a Streptococcus pneumoniae infection. It is important for the early identification and treatment of pneumococcal pneumosepsis.

IL-4 plays an essential role in DnaJ-ΔA146Ply-mediated immunoprotection against Streptococcus pneumoniae in mice.

The fusion protein DnaJ-ΔA146Ply is protective against pneumococcal infections in mice. However, we found that immunized IL-4-/- mice showed significant lower survival rates and higher bacterial loads than did wild-type (WT) mice after being challenged. We explored the role of IL-4 in the protective immunity conferred by DnaJ-ΔA146Ply. Our results showed that there were no significant differences in antibody titers between immunized WT mice and IL-4-/- mice. The bacterial loads of passively immunized IL-4-/- mice were significantly higher than those of WT mice, while mice immunized with anti-DnaJ-ΔA146Ply serum from WT and IL-4-/- mice showed similar capacity for bacterial clearance. DnaJ-ΔA146Ply-dependent phagocytosis of IL-4-/- neutrophils was significant decreased compared with that of WT neutrophils. The levels of Syk and phosphor-Syk in IL-4-/- neutrophils were decreased compared with those in WT neutrophils. Additionally, Splenocytes in IL-4-/- mice triggered significantly higher levels of IFN-γ and IL-17A than did splenocytes in WT mice. Taken together, our findings illustrate that IL-4 deficiency does not influence the antibody production or antibody effect, but change the cellular immune response induced by DnaJ-ΔA146Ply. Additionally, IL-4 can enhance the antibody-dependent phagocytosis of neutrophils partially by activating Syk and participate in the protective immunity induced by DnaJ-ΔA146Ply.

IL-27 as a potential biomarker for distinguishing between necrotising enterocolitis and highly suspected early-onset food protein-induced enterocolitis syndrome with abdominal gas signs.

BACKGROUND: The initial clinical manifestations and abdominal imaging findings of neonates with necrotising enterocolitis (NEC) and food protein-induced enterocolitis syndrome (FPIES) are sometimes similar; however, their prognosis and therapies are different. We aimed to evaluate the utility of interleukin (IL)-27 as a differentiation marker between NEC and highly suspected early onset (HSEO)-FPIES. METHODS: All samples used in this study were obtained from the neonatal diagnosis centre of Children's Hospital of Chongqing Medical University. In the case-control study, neonates with NEC (n = 13), HSEO-FPIES (n = 9), and jaundice (control, n = 8) were enroled to determine the serum IL-27 levels using commercial enzyme-linked immunosorbent assay (ELISA) kits. In the validation cohort study, the NEC (n = 87), HSEO-FPIES (n = 62), and jaundice (control, n = 54) groups were included to analyse the diagnostic efficiency of IL-27 for discriminating between NEC and HSEO-FPIES using a receiver operating characteristic (ROC) curve. FINDINGS: In the case-control study, IL-27 levels were higher in the NEC group than in the HSEO-FPIES group (p = 0·005). In the cohort study, the area under the ROC curve (AUC) of IL-27 for differentiating NEC from HSEO-FPIES was 0·878, which was higher than the AUCs of IL-6 (0·761), C-reactive protein (0·800), white blood cell count (0·637), neutrophils (0·765), lymphocytes (0·782), neutrophil to lymphocyte ratio (0·781), and platelet count (0·729). INTERPRETATION: Serum IL-27 is a novel biomarker that may potentially discriminate NEC from HSEO-FPIES in neonates. FUNDING: None.

Muc5ac Production Inhibited by Decreased lncRNA H19 via PI3K/Akt/NF-kB in Asthma.

INTRODUCTION: LncRNAs play important roles in multiple diseases including asthma, while there are a few reports on the role of lncRNA H19 about asthma. This study aimed to investigate the roles and mechanisms of lncRNA H19 in asthma. METHODS: We detected lncRNA H19 and Muc5ac mRNA by establishing a murine asthma model and an in vitro inflammation model. Regulatory roles of lncRNA H19 in asthma were explored by lncRNA H19 overexpression or knockdown in vitro. To study its mechanisms, we detect p-NF-κB and p-Akt expression, and treated 16-HBE cells with inhibitors of PI3K. To study regulatory effects of miR-675-3p on Muc5ac, miR-675-3p mimics and inhibitors were respectively transfected into 16-HBE cells. RESULTS: Firstly, we established a murine asthma model and an in vitro inflammation model. We found that lncRNA H19 expression was decreased, while Muc5ac mRNA was increased in lung tissues of murine asthma model and in the in vitro inflammation model. lncRNA H19 overexpression increased Muc5ac mRNA expression and lncRNA H19 knockdown decreased Muc5ac mRNA expression in 16-HBE cells. Moreover, lncRNA H19 overexpression further increased Muc5ac expression in TNFα-induced in vitro inflammation model. lncRNA H19 knockdown decreased p-Akt and p-NF-κB expression. Inhibitors of PI3K abolished Muc5ac induced by lncRNA H19 overexpression. Although miR-675-3p was increased by lncRNA H19 overexpression, it had no regulatory effects on Muc5ac expression. DISCUSSION: These results demonstrated that lncRNA H19 positively regulates Muc5ac expression through PI3K/Akt /NF-κB pathway in the in vitro inflammation model. Therefore, this study indicated that decreased lncRNA H19 in asthma might play a protective role relieving mucus overproduction, and lncRNA H19 might be a potential target for asthma treatment.

Biomineralization improves the stability of a Streptococcus pneumoniae protein vaccine at high temperatures.

Aim: Protein vaccines have been the focus of research for vaccine development due to their safety record and facile production. Improving the stability of proteins is of great significance to the application of protein vaccines. Materials & methods: Based on the proteins pneumolysin and DnaJ of Streptococcus pneumoniae, biomineralization was carried out to prepare protein nanoparticles, and their thermal stability was tested both in vivo and in vitro. Results: Mineralized nanoparticles were formed successfully and these calcium phosphate-encapsulated proteins were resistant to proteinase K degradation and were thermally stable at high temperatures. The mineralized proteins retained the immunoreactivity of the original proteins. Conclusion: Mineralization technology is an effective means to stabilize protein vaccines, presenting a safe and economical method for vaccine administration.

Interleukin-4 protects mice against lethal influenza and Streptococcus pneumoniae co-infected pneumonia.

Streptococcus pneumoniae co-infection post-influenza is a major cause of mortality characterized by uncontrolled bacteria burden and excessive immune response during influenza pandemics. Interleukin (IL)-4 is a canonical type II immune cytokine known for its wide range of biological activities on different cell types. It displays protective roles in numerous infectious diseases and immune-related diseases, but its role in influenza and S. pneumoniae (influenza/S. pneumoniae) co-infected pneumonia has not been reported. In our study, we used C57BL/6 wild-type (WT) and IL-4-deficient (IL-4-/- ) mice to establish co-infection model with S. pneumoniae after influenza virus infection. Co-infected IL-4-/- mice showed increased mortality and weight loss compared with WT mice. IL-4 deficiency led to increased bacterial loads in lungs without altering influenza virus replication, suggesting a role of IL-4 in decreasing post-influenza susceptibility to S. pneumoniae co-infection. Loss of IL-4 also resulted in aggravated lung damage together with massive proinflammatory cytokine production and immune cell infiltration during co-infection. Administration of recombinant IL-4 rescued the survival and weight loss of IL-4-/- mice in lethal co-infection. Additionally, IL-4 deficiency led to more immune cell death in co-infection. Gasdermin D (GSDMD) during co-infection was induced in IL-4-/- mice that subsequently activated cell pyroptosis. Treatment of recombinant IL-4 or inhibition of GSDMD activity by disulfiram decreased immune cell death and bacterial loads in lungs of IL-4-/- co-infected mice. These results suggest that IL-4 decreases post-influenza susceptibility to S. pneumoniae co-infection via suppressing GSDMD-induced pyroptosis. Collectively, this study demonstrates the protective role of IL-4 in influenza/S. pneumoniae co-infected pneumonia.

Streptococcus pneumoniae Endopeptidase O Promotes the Clearance of Staphylococcus aureus and Streptococcus pneumoniae via SH2 Domain-Containing Inositol Phosphatase 1-Mediated Complement Receptor 3 Upregulation.

Increasing evidences demonstrate that microorganism and their products protect against bacterial and viral pathogens through various mechanisms including immunomodulation. Streptococcus pneumoniae endopeptidase O (PepO), a pneumococcal virulence protein, has been proven to enhance the phagocytosis of Staphylococcus aureus and Streptococcus pneumoniae by macrophages in our previous study, where we detected the down regulation of SH2 domain-containing inositol phosphatase 1 (SHIP1) and the up regulation of complement receptor 3 (CR3) in PepO-stimulated macrophages. In the present study, using SHIP1 over-expression plasmid and CR3 siRNA, we proved that the down regulation of SHIP1 and the up regulation of CR3 mediate the enhanced phagocytosis of S. aureus and S. pneumoniae by PepO-stimulated macrophages. The down regulation of SHIP1 also mediates the up regulation of CR3. To further determine whether PepO protects against respiratory pathogens, we constructed a mouse model with intranasal infection of S. aureus or S. pneumoniae and found that PepO significantly promoted their clearance. The down regulation of SHIP1 and the up regulation of CR3 also play a role in this process. This study provides a new preventive and therapeutic option for respiratory infectious diseases and lays the theoretical basis for the development of PepO as an immunomodulation agent.

Combination of Detoxified Pneumolysin Derivative ΔA146Ply and Berbamine as a Treatment Approach for Breast Cancer.

Increasing evidence demonstrates that microorganisms and their products can modulate host responses to cancer therapies and contribute to tumor shrinkage via various mechanisms, including intracellular signaling pathways modulation and immunomodulation. Detoxified pneumolysin derivative ΔA146Ply is a pneumolysin mutant lacking hemolytic activity. To determine the antitumor activity of ΔA146Ply, the combination of ΔA146Ply and berbamine, a well-established antitumor agent, was used for breast cancer therapy, especially for triple-negative breast cancer. The efficacy of the combination therapy was evaluated in vitro using four breast cancer cell lines and in vivo using a synergistic mouse tumor model. We demonstrated that in vitro, the combination therapy significantly inhibited cancer cell proliferation, promoted cancer cell apoptosis, caused cancer cell-cycle arrest, and suppressed cancer cell migration and invasion. In vivo, the combination therapy significantly suppressed tumor growth and prolonged the median survival time of tumor-bearing mice partially through inhibiting tumor cell proliferation, promoting tumor cell apoptosis, and activating systemic antitumor immune responses. The safety analysis demonstrated that the combination therapy showed no obvious liver and kidney toxicity to tumor-bearing mice. Our study provides a new treatment option for breast cancer and lays the experimental basis for the development of ΔA146Ply as an antitumor agent.

Streptococcus pneumoniae aminopeptidase N regulates dendritic cells that attenuates type-2 airway inflammation in murine allergic asthma.

BACKGROUND AND PURPOSE: Epidemiological and experimental studies suggest that microbial exposure in early childhood is linked with reduced risk to suffer asthma. Thus microbial components with immunoregulatory capabilities might serve as a preventive strategy for allergic asthma. Recently, it was identified that Streptococcus pneumoniae aminopeptidase N (PepN) could suppress T cell effector function. We sought to investigate the effect of PepN on murine allergic asthma and elucidate the underlying mechanism. EXPERIMENTAL APPROACH: The effects of intranasal administration of PepN during or before sensitization were examined in ovalbumin (OVA)-induced murine allergic asthma. The roles of CD11b+ dendritic cells in PepN treated OVA-induced allergic asthma were evaluated by flow cytometry, cytokines detection and adoptive transfer. Moreover, the numbers of lung type 2 innate lymphoid cells (ILC2s) were also detected. KEY RESULTS: Administration of PepN during or before sensitization attenuated type-2 airway inflammation (eosinophilia, mucus hypersecretion, Th2 cytokines production and IgE production) in allergic asthma mice. PepN reduced lung accumulation of CD11b+ dendritic cells, which was accompanied by diminished dendritic cell-attracting chemokine CCL20 production as well as CCL17 and CCL22, which are Th2-cell chemokines predominantly produced by CD11b+ dendritic cells. Adoptive transfer of BM-derived CD11b+ dendritic cells abolished the inhibitory effect of PepN on OVA-induced type-2 airway inflammation. The numbers of lung ILC2s were decreased in asthmatic mice receiving PepN. CONCLUSION AND IMPLICATIONS: PepN alleviated type-2 inflammation in OVA-induced allergic asthma mice, which was mediated by regulation of lung CD11b+ dendritic cells. Our study provides a novel strategy for the prevention of allergic asthma.

Cytosolic mtDNA released from pneumolysin-damaged mitochondria triggers IFN-ß production in epithelial cells.

Pneumolysin (Ply) is a major virulence factor of Streptococcus pneumoniae. Ply-induced interferon-ß (IFN-ß) expression in host macrophages has been shown to be due to the accumulation of mitochondrial deoxyribonucleic acid (mtDNA) in the cytoplasm during S. pneumoniae infection. Our findings extend this work to show human bronchial epithelial cells that reside at the interface of inflammatory injury, BEAS-2B, adapt to local cues by altering mitochondrial states and releasing excess mtDNA. The results in this research showed that purified Ply induced the expression of IFN-ß in human epithelial cells, which was accompanied by mitochondrial damage both in vivo and in vitro. The observations also were supported by the increased mtDNA concentrations in the bronchial lavage fluid of mice infected with S. pneumoniae. In summary, our study demonstrated that Ply triggered the production of IFN-ß in epithelial cells, and this response was mediated by mtDNA released from Ply-damaged mitochondria. It displayed an impressive modulation of IFN-ß response to S. pneumoniae in epithelial cells.

Streptococcus pneumoniae aminopeptidase N contributes to bacterial virulence and elicits a strong innate immune response through MAPK and PI3K/AKT signaling.

Streptococcus pneumoniae is a Gram-positive pathogen with high morbidity and mortality globally but some of its pathogenesis remains unknown. Previous research has provided evidence that aminopeptidase N (PepN) is most likely a virulence factor of S. pneumoniae. However, its role in S. pneumoniae virulence and its interaction with the host remains to be confirmed. We generated a pepN gene deficient mutant strain and found that its virulence for mice was significantly attenuated as were in vitro adhesion and invasion of host cells. The PepN protein could induce a strong innate immune response in vivo and in vitro and induced secretion of IL-6 and TNF-α by primary peritoneal macrophages via the rapid phosphorylation of MAPK and PI3K/AKT signaling pathways and this was confirmed using specific pathway inhibitors. In conclusion, PepN is a novel virulence factor that is essential for the virulence of S. pneumoniae and induces host innate immunity via MAPK and PI3K/AKT signaling.

miR-29b Reverses T helper 1 cells/T helper 2 cells Imbalance and Alleviates Airway Eosinophils Recruitment in OVA-Induced Murine Asthma by Targeting Inducible Co-Stimulator.

Asthma is a complex chronic disease and the pathogenesis is still not entirely clear. In this study, we aimed to clarify the role and mechanism of miR-29b in the development of asthma. We observed that miR-29b levels were decreased in the lung and spleen of OVA-induced asthmatic mice. Reverse transcription-quantitative polymerase chain reaction and flow cytometry demonstrated that the inducible co-stimulator (ICOS) expression at mRNA and protein levels was elevated in the lung of asthmatic mice, and miR-29b expression in the lung of asthmatic mice was negatively associated with ICOS mRNA levels by Pearson Correlation analysis. Additional, flow cytometry showed that the percentage of CD4+ICOS+ T cells in the lung and spleen was regulated by miR-29b, and dual luciferase reporter assay confirmed ICOS was a target gene of miR-29b. Furthermore, miR-29b overexpression in asthmatic mice was induced with miR-29b agomir by intranasal administration; miR-29b alleviated total inflammatory cell infiltration and CCL24 levels, decreased IL-5 levels in bronchoalveolar lavage fluid and serum, and upregulated IFN-γ expression in serum. This study demonstrates that miR-29b targets ICOS, thereby reverses the imbalance of T helper 1 cells (Th1)/Th2 responses and decreases eosinophils recruitment in the airway, which are key features of allergic airway inflammation. Therefore, miR-29b might be an attractive candidate target for asthma treatment.