Immune Network最新文献

Cigarette smoke extract (CSE)-treated mouse airway epithelial cells (MAECs)-derived exosomes accelerate the progression of chronic obstructive pulmonary disease (COPD) by upregulating triggering receptor expressed on myeloid cells 1 (TREM-1); however, the specific mechanism remains unclear. We aimed to explore the potential mechanisms of CSE-treated MAECs-derived exosomes on M1 macrophage polarization and pyroptosis in COPD. In vitro, exosomes were extracted from CSE-treated MAECs, followed by co-culture with macrophages. In vivo, mice exposed to cigarette smoke (CS) to induce COPD, followed by injection or/and intranasal instillation with oe-TREM-1 lentivirus. Lung function and pathological changes were evaluated. CD68⁺ cell number and the levels of iNOS, TNF-α, IL-1β (M1 macrophage marker), and pyroptosis-related proteins (NOD-like receptor family pyrin domain containing 3, apoptosis-associated speck-like protein containing a caspase-1 recruitment domain, caspase-1, cleaved-caspase-1, gasdermin D [GSDMD], and GSDMD-N) were examined. The expression of maternally expressed gene 3 (MEG3), spleen focus forming virus proviral integration oncogene (SPI1), methyltransferase 3 (METTL3), and TREM-1 was detected and the binding relationships among them were verified. MEG3 increased N6-methyladenosine methylation of TREM-1 by recruiting SPI1 to activate METTL3. Overexpression of TREM-1 or METTL3 negated the alleviative effects of MEG3 inhibition on M1 polarization and pyroptosis. In mice exposed to CS, EXO^-CSE further aggravated lung injury, M1 polarization, and pyroptosis, which were reversed by MEG3 inhibition. TREM-1 overexpression negated the palliative effects of MEG3 inhibition on COPD mouse lung injury. Collectively, CSE-treated MAECs-derived exosomal long non-coding RNA MEG3 may expedite M1 macrophage polarization and pyroptosis in COPD via the SPI1/METTL3/TREM-1 axis.

IL-18 binding protein (IL-18BP) was originally discovered in 1999 while attempting to identify an IL-18 receptor ligand binding chain (also known as IL-18Rα) by subjecting concentrated human urine to an IL-18 ligand affinity column. The IL-18 ligand chromatography purified molecule was analyzed by protein microsequencing. The result revealed a novel 40 amino acid polypeptide. To isolate the complete open reading frame (ORF), various human and mouse cDNA libraries were screened using cDNA probe derived from the novel IL-18 affinity column bound molecule. The identified entire ORF gene was thought to be an IL-18Rα gene. However, IL-18BP has been proven to be a unique soluble antagonist that shares homology with a variety of viral proteins that are distinct from the IL-18Rα and IL-18Rβ chains. The IL-18BP cDNA was used to generate recombinant IL-18BP (rIL-18BP), which was indispensable for characterizing the role of IL-18BP in vitro and in vivo. Mammalian cell lines were used to produce rIL-18BP due to its glycosylation-dependent activity of IL-18BP (approximately 20 kDa). Various forms of rIL-18BP, intact, C-terminal his-tag, and Fc fusion proteins were produced for in vitro and in vivo experiments. Data showed potent neutralization of IL-18 activity, which seems promising for clinical application in immune diseases involving IL-18. However, it was a long journey from discovery to clinical use although there have been various clinical trials since IL-18BP was discovered in 1999. This review primarily covers the discovery of IL-18BP along with how basic research influences the clinical development of IL-18BP.

Mesenchymal stromal/stem cells (MSCs) possess immunoregulatory properties and their regulatory functions represent a potential therapy for acute lung injury (ALI). However, uncertainties remain with respect to defining MSCs-derived immunomodulatory pathways. Therefore, this study aimed to investigate the mechanism underlying the enhanced effect of human recombinant bone morphogenic protein-2 (rhBMP-2) primed ES-MSCs (MSC^BMP2) in promoting Tregs in ALI mice. MSC were preconditioned with 100 ng/ml rhBMP-2 for 24 h, and then administrated to mice by intravenous injection after intratracheal injection of 1 mg/kg LPS. Treating MSCs with rhBMP-2 significantly increased cellular proliferation and migration, and cytokines array reveled that cytokines release by MSC^BMP2 were associated with migration and growth. MSC^BMP2 ameliorated LPS induced lung injury and reduced myeloperoxidase activity and permeability in mice exposed to LPS. Levels of inducible nitric oxide synthase were decreased while levels of total glutathione and superoxide dismutase activity were further increased via inhibition of phosphorylated STAT1 in ALI mice treated with MSC^BMP2. MSC^BMP2 treatment increased the protein level of IDO1, indicating an increase in Treg cells, and Foxp3⁺CD25⁺ Treg of CD4⁺ cells were further increased in ALI mice treated with MSC^BMP2. In co-culture assays with MSCs and RAW264.7 cells, the protein level of IDO1 was further induced in MSC^BMP2. Additionally, cytokine release of IL-10 was enhanced while both IL-6 and TNF-α were further inhibited. In conclusion, these findings suggest that MSC^BMP2 has therapeutic potential to reduce massive inflammation of respiratory diseases by promoting Treg cells.

Scrub typhus, a mite-borne infectious disease, is caused by Orientia tsutsugamushi. Despite many attempts to develop a protective strategy, an effective preventive vaccine has not been developed. The identification of appropriate Ags that cover diverse antigenic strains and provide long-lasting immunity is a fundamental challenge in the development of a scrub typhus vaccine. We investigated whether this limitation could be overcome by harnessing the nanoparticle-forming polysorbitol transporter (PST) for an O. tsutsugamushi vaccine strategy. Two target proteins, 56-kDa type-specific Ag (TSA56) and surface cell Ag A (ScaA) were used as vaccine candidates. PST formed stable nano-size complexes with TSA56 (TSA56-PST) and ScaA (ScaA-PST); neither exhibited cytotoxicity. The formation of Ag-specific IgG2a, IgG2b, and IgA in mice was enhanced by intranasal vaccination with TSA56-PST or ScaA-PST. The vaccines containing PST induced Ag-specific proliferation of CD8⁺ and CD4⁺ T cells. Furthermore, the vaccines containing PST improved the mouse survival against O. tsutsugamushi infection. Collectively, the present study indicated that PST could enhance both Ag-specific humoral immunity and T cell response, which are essential to effectively confer protective immunity against O. tsutsugamushi infection. These findings suggest that PST has potential for use in an intranasal vaccination strategy.

Autoimmune hepatitis (AIH) affects all age group and occurs mainly in women. Pyroptosis is a novel programmed cell death featured with cell bursting and release of proinflammatory cytokines. A deeper understanding of AIH pathogenesis will contribute to novel therapy for AIH patients. Here, we aimed to investigate the role of IL-17 in immune-mediated liver injury. The levels of cytokines were measured by ELISA, and mRNA levels of STAT3 and IFN gamma-inducible protein 16 (IFI16) were detected by PCR. Expressions of STAT3, IFI16, gasdermin D and cleaved caspase-1 were measured by western-blotting. Immunohistochemical staining and transmission electron microscopy were applied to evaluate liver histopathological changes of the treated mice. Our results showed that the levels of IFI16 was increased in hepatocytes treated with IL-17 protein, and further elevated after STAT3-overexpressed (STAT3-OE) lentivirus treatment. The levels of IFI16 were reduced in hepatocytes treated with IL-17 neutralizing Ab (nAb), but were significantly increased after STAT3-OE treatment. Pyroptosis was observed in hepatocytes treated with IL-17 protein, and further cell damage was observed after STAT3-OE lentivirus treatment. Liver damage was alleviated in mice treated with IL-17 nAb, however sever damage was experienced after STAT3-OE lentivirus treatment. A binding interaction between IFI16 and STAT3 was detected in IL-17 treated hepatocytes. Glutathione transaminase activity was enhanced in concanavalin A-induced AIH mice compared to the control group (p<0.01). IL-17 plays an important role in activating STAT3 and up-regulating IFI16, which may promote the pyroptosis in AIH-related liver injury through STAT3-IFI16 axis.

Interstitial lung disease (ILD) involves persistent inflammation and fibrosis, leading to respiratory failure and even death. Adult tissue-derived mesenchymal stem cells (MSCs) show potential in ILD therapeutics but obtaining an adequate quantity of cells for drug application is difficult. Daewoong Pharmaceutical's MSCs (DW-MSCs) derived from embryonic stem cells sustain a high proliferative capacity following long-term culture and expansion. The aim of this study was to investigate the therapeutic potential of DW-MSCs in experimental mouse models of ILD. DW-MSCs were expanded up to 12 passages for in vivo application in bleomycin-induced pulmonary fibrosis and collagen-induced connective tissue disease-ILD mouse models. We assessed lung inflammation and fibrosis, lung tissue immune cells, fibrosis-related gene/protein expression, apoptosis and mitochondrial function of alveolar epithelial cells, and mitochondrial transfer ability. Intravenous administration of DW-MSCs consistently improved lung fibrosis and reduced inflammatory and fibrotic markers expression in both models across various disease stages. The therapeutic effect of DW-MSCs was comparable to that following daily oral administration of nintedanib or pirfenidone. Mechanistically, DW-MSCs exhibited immunomodulatory effects by reducing the number of B cells during the early phase and increasing the ratio of Tregs to Th17 cells during the late phase of bleomycin-induced pulmonary fibrosis. Furthermore, DW-MSCs exhibited anti-apoptotic effects, increased cell viability, and improved mitochondrial respiration in alveolar epithelial cells by transferring their mitochondria to alveolar epithelial cells. Our findings indicate the strong potential of DW-MSCs in the treatment of ILD owing to their high efficacy and immunomodulatory and anti-apoptotic effects.

Mesenchymal stem cells (MSCs) are effective in treating autoimmune diseases and managing various conditions, such as engraftment of allogeneic islets. Additionally, autologous and HLA-matched allogeneic MSCs can aid in the engraftment of human allogeneic kidneys with or without low doses of tacrolimus, respectively. However, HLA alloantigens are problematic because cell therapy uses more HLA-mismatched allogeneic cells than autologous for convenience and standardization. In particular, HLA-mismatched MSCs showed increased Ag-specific T/B cells and reduced viability faster than HLA-matched MSCs. In CRISPR/Cas9-based cell therapy, Cas9 induce T cell activation in the recipient's immune system. Interestingly, despite their immunogenicity being limited to the cells with foreign Ags, the accumulation of HLA alloantigen-sensitized T/B cells may lead to allograft rejection, suggesting that alloantigens may have a greater scope of adverse effects than foreign Ags. To avoid alloantigen recognition, the β2-microglobulin knockout (B2MKO) system, eliminating class-I MHC, was able to avoid rejection by alloreactive CD8 T cells compared to controls. Moreover, universal donor cells in which both B2M and Class II MHC transactivator (CIITA) were knocked out was more effective in avoiding immune rejection than single KO. However, B2MKO and CIITA KO system remain to be controlled and validated for adverse effects such as the development of tumorigenicity due to deficient Ag recognition by CD8 T and CD4 T cells, respectively. Overall, better HLA-matching or depletion of HLA alloantigens prior to cell therapy can reduce repetitive transplantation through the long-term survival of allogeneic cell therapy, which may be especially important for patients seeking allogeneic transplantation.

The continuous emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants has provided insights for updating current coronavirus disease 2019 (COVID-19) vaccines. We examined the neutralizing activity of Abs induced by a BA.4/5-containing bivalent mRNA vaccine against Omicron subvariants BN.1 and XBB.1.5. We recruited 40 individuals who had received a monovalent COVID-19 booster dose after a primary series of COVID-19 vaccinations and will be vaccinated with a BA.4/5-containing bivalent vaccine. Sera were collected before vaccination, one month after, and three months after a bivalent booster. Neutralizing Ab (nAb) titers were measured against ancestral SARS-CoV-2 and Omicron subvariants BA.5, BN.1, and XBB.1.5. BA.4/5-containing bivalent vaccination significantly boosted nAb levels against both ancestral SARS-CoV-2 and Omicron subvariants. Participants with a history of SARS-CoV-2 infection had higher nAb titers against all examined strains than the infection-naïve group. NAb titers against BN.1 and XBB.1.5 were lower than those against the ancestral SARS-CoV-2 and BA.5 strains. These results suggest that COVID-19 vaccinations specifically targeting emerging Omicron subvariants, such as XBB.1.5, may be required to ensure better protection against SARS-CoV-2 infection, especially in high-risk groups.

When the lungs are infected with bacteria, alveolar macrophages (AMs) are recruited to the site and play a crucial role in protecting the host by reducing excessive lung inflammation. However, the regulatory mechanisms that trigger the recruitment of AMs to lung alveoli during an infection are still not fully understood. In this study, we identified a critical role for NADPH oxidase 4 (NOX4) in the recruitment of AMs during Staphylococcus aureus lung infection. We found that NOX4 knockout (KO) mice showed decreased recruitment of AMs and increased lung neutrophils and injury in response to S. aureus infection compared to wild-type (WT) mice. Interestingly, the burden of S. aureus in the lungs was not different between NOX4 KO and WT mice. Furthermore, we observed that depletion of AMs in WT mice during S. aureus infection increased the number of neutrophils and lung injury to a similar level as that observed in NOX4 KO mice. Additionally, we found that expression of intercellular adhesion molecule-1 (ICAM1) in NOX4 KO mice-derived lung endothelial cells was lower than that in WT mice-derived endothelial cells. Therefore, we conclude that NOX4 plays a crucial role in inducing the recruitment of AMs by controlling ICAM1 expression in lung endothelial cells, which is responsible for resolving lung inflammation during acute S. aureus infection.

CD4 and CD8 T cells are key players in the immune response against both pathogenic infections and cancer. CD4 T cells provide help to CD8 T cells via multiple mechanisms, including licensing dendritic cells (DCs), co-stimulation, and cytokine production. During acute infection and vaccination, CD4 T cell help is important for the development of CD8 T cell memory. However, during chronic viral infection and cancer, CD4 helper T cells are critical for the sustained effector CD8 T cell response, through a variety of mechanisms. In this review, we focus on T cell responses in conditions of chronic Ag stimulation, such as chronic viral infection and cancer. In particular, we address the significant role of CD4 T cell help in promoting effector CD8 T cell responses, emerging techniques that can be utilized to further our understanding of how these interactions may take place in the context of tertiary lymphoid structures, and how this key information can be harnessed for therapeutic utility against cancer.