IL32γ activates natural killer receptor-expressing innate immune cells to produce IFNγ via dendritic cell-derived IL12

Phosphorothioate-linked guanine/cytosine-based stem-loop oligonucleotides induce the extracellular release of mitochondrial DNA from peritoneal B1a cells

It has been previously demonstrated that phosphorothioate-linked GpC-based stem-loop oligonucleotides (GC-SL ODN) induce the release of mitochondrial DNA (mtDNA) from chronic lymphocytic leukemia (CLL) B cells. Although CLL B cells are believed to originate from CD5⁺ B cells because of their phenotypic similarities, it remains unclear whether GC-SL ODN can stimulate CD5⁺ B1 cells to secrete mtDNA. To explore this possibility, we compared the frequency of the mtDNA-producing population among peritoneal cells after GC-SL ODN treatment. We found that mtDNA-releasing cells are enriched for peritoneal CD19⁺ B cells upon GC-SL ODN challenge. Among peritoneal CD19⁺ B cells, the CD5⁺ B1a subpopulation was a primary cellular source of mtDNA secretion in GC-SL ODN-elicited immune responses. GC-SL ODN-stimulated mtDNA release by B1a cells was positively regulated by MyD88 and TRIF signaling pathways. In vivo GC-SL ODN treatment increased lipopolysaccharide-induced activation of innate immune cells such as NK cells, suggesting the immune-enhancing effects of mtDNA secretion. Furthermore, the loop size formed by GC-SL ODNs was a critical factor in inducing mtDNA release by B1a cells. Taken together, our results identified GC-SL ODN as promising biomaterials for enhancing immune responses.

Down-regulation of IL-32γ expression reduces killing effect of natural killer cells on esophageal carcinoma cells

BACKGROUND

Interleukin (IL)-32γ is highly expressed in activated natural killer (NK) cells in esophageal cancer. However, it is not clear whether the expression level of IL-32γ in NK cells affects their killing effect on esophageal cancer cells.

AIM

To investigate the role of IL-32γ in the anti-tumor effect of NK cells in esophageal cancer.

METHODS

After transfecting NK-92 cells with shRNA targeting IL-32γ (shIL-32γ), the NK-92 cells were co-cultured with esophageal cancer cells EC9706 and TE-1, respectively. EC9706 and TE-1 cells were then collected; cell viability was measured by cell counting kit-8 (CCK-8) assay, cell proliferation was detected by 5-ethynyl-2'-deoxyuridine (EDU) assay, cell apoptosis was detected by flow cytometry, and the expression of apoptosis-related proteins B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X (Bax), cleaved cysteine-containing aspartate-specific proteases 3 (caspase 3), tumor necrosis factor receptor superfamily member 6 (FAS), death receptor 3 (DR3), and tumor necrosis factor receptor 2 (TNFR2) was detected by Western blot.

RESULTS

After IL-32γ deletion in NK-92 cells, the cell viability and the EDU positive cells in EC9706 and TE-1 cells in the co-culture system were increased (P < 0.01), the expression level of Bcl-2 was increased (P < 0.01), and the expression levels of Bax, cleaved-caspase 3, FAS, DR3, and TNFR2 were all decreased (P < 0.01).

CONCLUSION

Knockdown of IL-32γ attenuates the anti-tumor effect of NK-92 cells, which may be related to the inhibition of death receptor expression and caspase-3 activation in esophageal cancer cells.

Chromatin Regulator SRG3 Overexpression Protects against LPS/D-GalN-Induced Sepsis by Increasing IL10-Producing Macrophages and Decreasing IFNγ-Producing NK Cells in the Liver

We previously showed that ubiquitous overexpression of the chromatin remodeling factor SWItch3-related gene (SRG3) promotes M2 macrophage differentiation, resulting in anti-inflammatory responses in the experimental autoimmune encephalomyelitis model of multiple sclerosis. Since hepatic macrophages are responsible for sepsis-induced liver injury, we investigated herein the capacity of transgenic SRG3 overexpression (SRG3β-actin mice) to modulate sepsis in mice exposed to lipopolysaccharide (LPS) plus d-galactosamine (d-GalN). Our results demonstrated that ubiquitous SRG3 overexpression significantly protects mice from LPS/d-GalN-induced lethality mediated by hepatic M1 macrophages. These protective effects of SRG3 overexpression correlated with the phenotypic conversion of hepatic macrophages from an M1 toward an M2 phenotype. Furthermore, SRG3β-actin mice had decreased numbers and activation of natural killer (NK) cells but not natural killer T (NKT) cells in the liver during sepsis, indicating that SRG3 overexpression might contribute to cross-talk between NK cells and macrophages in the liver. Finally, we demonstrated that NKT cell-deficient CD1d KO/SRG3β-actin mice are protected from LPS/d-GalN-induced sepsis, indicating that NKT cells are dispensable for SRG3-mediated sepsis suppression. Taken together, our findings provide strong evidence that SRG3 overexpression may serve as a therapeutic approach to control overwhelming inflammatory diseases such as sepsis.

Anti-cancer activity of Angelica gigas by increasing immune response and stimulating natural killer and natural killer T cells

Background

The polysaccharide component of Angelica gigas induces immuno-stimulatory effects on innate immune cells. However, it is unclear whether A. gigas’ adjuvant activity on the immune system can elicit anti-cancer responses.

Methods

A water-soluble immuno-stimulatory component of A. gigas was prepared. How this ISAg modulated the activation of innate immune cells such as dendritic cells (DCs) was examined. ISAg-induced cytotoxic activity via natural killer (NK) and NKT cells was also tested using a tumor-bearing mouse model.

Results

ISAg treatment induced nitric oxide (NO) production and cytokine gene expression involved in innate immune responses. ISAg activated macrophages and DCs to secrete cytokine IL-12, through the TLR4 signaling pathway. IL-12 plays a crucial role in ISAg-mediated NK and NKT cell activation. Thus, the anti-cancer activity of NK and NKT cells induced ISAg-mediated cytotoxicity of B16 melanoma cells in mice.

Conclusions

These results indicated that the natural ingredient, ISAg, has adjuvant activity to induce strong anti-cancer activity of NK and NKT cells in vivo.

Interleukin-32: An endogenous danger signal or master regulator of intracellular pathogen infections-Focus on leishmaniases

Interleukin 32 (IL-32) is an intracellular cytokine produced by immune and non immune cells after different stimuli. It contributes to inflammation and control of intracellular pathogens mainly by inducing proinflammatory cytokines and microbicidal molecules. Evidence is rising showing that IL-32 can be considered an endogenous danger signal after tissue injury, amplifying the inflammatory process and acquired immune responses. It seems to be a master regulator of intracellular infectious diseases. In this review, first the general properties of IL-32 are described followed by its role in the immunopathogenesis of inflammatory and infectious diseases. Roles of IL-32 in the control of infectious diseases caused by intracellular pathogens are reported, and later a focus on IL-32 in leishmaniases, diseases caused by an intracellular protozoan, is presented.

Further exploring the feasibility of dendritic cells-targeted biomimetic Texosomes as a therapeutic and preventive tumor-vaccine

Targeting tumor cells with immunotherapy by a dendritic cells-targeted vaccination is a potential treatment option.

iNKT Cells Are Responsible for the Apoptotic Reduction of Basophils That Mediate Th2 Immune Responses Elicited by Papain in Mice Following γPGA Stimulation

Recent studies have demonstrated that Bacillus subtilis-derived poly-gamma glutamic acid (γPGA) treatment suppresses the development of allergic diseases such as atopic dermatitis (AD). Although basophils, an innate immune cell, are known to play critical roles in allergic immune responses and repeated long-term administration of γPGA results in decreased splenic basophils in an AD murine model, the underlying mechanisms by which γPGA regulates basophil frequency remain unclear. To investigate how γPGA modulates basophils, we employed basophil-mediated Th2 induction in vivo model elicited by the allergen papain protease. Repeated injection of γPGA reduced the abundance of basophils and their production of IL4 in mice, consistent with our previous study using NC/Nga AD model mice. The depletion of basophils by a single injection of γPGA was dependent on the TLR4/DC/IL12 axis. CD1d-dependent Vα14 TCR invariant natural killer T (iNKT) cells are known to regulate a variety of immune responses, such as allergy. Because iNKT cell activation is highly sensitive to IL12 produced by DCs, we evaluated whether the effect of γPGA on basophils is mediated by iNKT cell activation. We found that in vivo γPGA treatment did not induce the reduction of basophils in iNKT cell-deficient CD1d KO mice, suggesting the critical role of iNKT cells in γPGA-mediated basophil depletion at the early time points. Furthermore, increased apoptotic basophil reduction triggered by iNKT cells upon γPGA stimulation was mainly attributed to Th1 cytokines such as IFNγ and TNFα, consequently resulting in inhibition of papain-induced Th2 differentiation via diminishing basophil-derived IL4. Taken together, our results clearly demonstrate that γPGA-induced iNKT cell polarization toward the Th1 phenotype induces apoptotic basophil depletion, leading to the suppression of Th2 immune responses. Thus, elucidation of the crosstalk between innate immune cells will contribute to the design and development of new therapeutics for Th2-mediated immune diseases such as AD.

Enhancement of anti-tumor immune responses induced by ligand-mediated biomimetic Texosomes

In order to overcome the immune tolerance and awake the tumor patients’ self immune response, hTERT-HSP70 as a universal tumor antigen is specifically transferred to dendritic cells by DEC205McAb Texosomes as the carriers of a tumor vaccine.