Insights into dendritic cell maturation during infection with application of advanced imaging techniques

Sishen pills inhibit inflammatory dendritic cell differentiation via miR-505-3p mediated E-cadherin downregulation in ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is an autoimmune disease that is highly susceptible to recurrence, which is still a lack of effective drugs with minor side effects in clinic. Intervention of inflammatory differentiation of dendritic cells (DCs) might be an effective strategy to treat UC. Sishen Pills (SSP) is a classic Chinese herbal formula which has been demonstrated the protective effect of UC, but the mechanism remains unclear.

PURPOSE

To elucidate the protective effects of SSP against UC in mice and reveal its regulatory mechanism of DCs and the key active ingredients for the UC treatment based on transcriptomics, network pharmacology and experiments validation in vivo and vitro.

METHOD

The key active ingredients of SSP were detected and screened integrating LC-MS/MS and network pharmacology. A mouse UC model was induced with 3% sodium dextran sulfate and treated with SSP for 14 days to evaluate the efficacy. ELISA was used to detect the levels of IL-6, IL-1β and TNF-α in the colon; flow cytometry was used to detect the expression levels of DCs and their subpopulations; whole transcriptomic sequencing of differential RNAs in the colon and RT-PCR to detect key miRNAs to verify the sequencing results. Mouse bone marrow-derived dendritic cells (BMDCs) were isolated, an inflammatory model was constructed using 100 ng/ml LPS, and the effects of SSP on DC proliferation and apoptosis and their surface co-stimulatory molecule expression were examined; IL-6, IL-1β, TNF-α levels were measured by ELISA; RT-PCR and WB were performed to detect miR-505-3p, CDH1, E-cadherin expression. BMDCs with low expression of miR-505-3p were constructed by lentiviral transfection for further validation. The potential key ingredient was re-validated in vivo and vitro experiment.

RESULTS

Animal experiments showed that SSP alleviated DSS-induced UC symptoms and colonic pathological injury in mice, and inhibited IL-6, IL-1β, TNF-α secretion and inflammatory DC proliferation and activation maturation. Network pharmacology predicted that evodiamine, isobavachalcone, curcumin, and engenol may play a key role in SSP. RNA sequencing revealed that miR-505-3p, as the differential miRNA, shared a large number of transcription factors with E-cadherin, and was involved in inflammatory differentiation regulation. In vivo experiments confirmed that SSP accelerated apoptosis, slowed down proliferation, inhibited inflammatory differentiation and IL-6, IL-1β, and TNF-α secretion in BMDCs, and decreased miR-505-3p, CDH1, and E-cadherin levels. After knocking down miR-505-3p, SSP could not regulate the inflammatory differentiation and IL-6, IL-1β, TNF-α level in BMDCs. Additionally, evodiamine was found and verified to be the key active ingredient of SSP in preventing the inflammatory differatiation of DCs.

CONCLUSION

SSP prevented the inflammatory differentiation of DCs by downregulating the expression of miR-505-3p, in which Evodiamine may played a key role.

Tumor Antigen-Tethered Spiked Virus-Like- Poly(Lactic-Co-Glycolic Acid)-Nanoparticle Vaccine Enhances Antitumor Ability Through Th9 Promotion in Mice

Purpose

Immunotherapy emerges as a promising frontier in cancer therapy and prevention. This study investigates the capacity of tumor-antigenic nanoparticles, specifically ovalbumin-tethered spiked virus-like poly(lactic-co-glycolic acid) nanoparticles (OVA-sVLNP), to effectively elicit humoral and cellular immune responses against tumors.

Methods

OVA-sVLNP were synthesized through thiol-maleimide crosslinking using a single emulsion method. Comprehensive characterization was performed through Nuclear Magnetic Resonance (NMR), dynamic light scattering, Cryo-electron microscopy (Cryo-EM), confocal microscopy, and flow cytometry. Immunogenicity was evaluated using an enzyme-linked immunosorbent assay (ELISA) for quantifying immunoglobulin levels (IgG, IgG1, IgG2a) and cytokines in mouse sera. Flow cytometry profiled cellular immune responses in mouse spleens, and organ biosafety was assessed using immunohistochemistry and hematoxylin and eosin (H&E) staining.

Results

OVA-sVLNP had a mean particle size of 193.8 ± 11.9 nm, polydispersity index of 0.307 ± 0.04, and zeta potential of -39.6 ± 10.16 mV, remaining stable for one month at 4°C. In vitro studies revealed significant upregulation of CD80/CD86 in dendritic cells, indicating robust activation. In vivo, the optimal concentration (V25) induced potent IgG, IgG1, and IgG2a antibodies, significant populations of CD3+CD4+, CD3+CD8+, and a rare subset of CD3+CD4+CD8+ memory T cells. Notably, Th9 induction resulted in the secretion of IL-9, IL-10, and other cytokines, which are crucial for orchestrating cytotoxic T cell activity and antitumor effects. Overall, higher doses did not improve outcomes, highlighting the significance of optimal dosing.

Conclusion

This study demonstrated potent immunogenicity of OVA-sVLNP, characterized by the induction of specific IgG antibodies and the stimulation of cellular immune responses, particularly tumor-killing Th9 cells. The simplicity and cost-effectiveness of the manufacturing process augment the potential of OVA-sVLNP as a viable candidate for antitumor vaccines, opening new avenues for cancer prevention and cell-based therapeutic strategies.

A protocol to isolate and characterize pure monocytes and generate monocyte-derived dendritic cells through FBS-Coated flasks

This study explores methods to isolate high-pure monocytes and optimize the best growth factor concentration to generate monocytes-derived dendritic cells (mo-DCs), subset DC1, which is crucial in immune responses. Three protocols for monocyte isolation from peripheral blood mononuclear cells (PBMCs) were evaluated: three-hour incubation on FBS-coated flasks; an overnight incubation on FBS-coated flasks; and Magnetic Activated Cell Sorting (MACS). Additionally, five different concentrations of human recombinant granulocyte-macrophage colony-stimulating factor (hrGM-CSF) and human recombinant interleukin-4 (hrIL-4) were compared. We used Flow cytometry to assess the isolation, purification, and generation of pure monocytes characterized as CD14+, and expression of mo-DC classical markers (HLA-DR, CD80, CD83, and CD86). The obtained results show that monocytes isolated with the second method (overnight incubation) had the highest purity (P < 0.0001) but the lowest yield (P > 0.05), balancing purity and cost-effectiveness. A combination of hrGM-CSF and hrIL-4 at 400 U/mL produced the most favorable outcomes, leading to the highest rate of mo-DC generation (P < 0.05). Notably, this concentration resulted in increasing expression of HLA-DR, CD80, and CD86 surface markers in the generated DCs (P < 0.0001), with no changes in CD83 expression levels. In conclusion, this study offers valuable insights into selecting the optimal approach for monocyte isolation and mo-DC generation in various research contexts, providing a foundation for more effective immunological studies.

The Immune Microenvironment in Prostate Cancer: A Comprehensive Review

BACKGROUND

Prostate cancer (PCa) is a malignancy with significant immunosuppressive properties and limited immune activation. This immunosuppression is linked to reduced cytotoxic T cell activity, impaired antigen presentation, and elevated levels of immunosuppressive cytokines and immune checkpoint molecules. Studies demonstrate that cytotoxic CD8+ T cell infiltration correlates with improved survival, while increased regulatory T cells (Tregs) and tumor-associated macrophages (TAMs) are associated with worse outcomes and therapeutic resistance. Th1 cells are beneficial, whereas Th17 cells, producing interleukin-17 (IL-17), contribute to tumor progression. Tumor-associated neutrophils (TANs) and immune checkpoint molecules, such as PD-1/PD-L1 and T cell immunoglobulin-3 (TIM-3) are also linked to advanced stages of PCa. Chemotherapy holds promise in converting the "cold" tumor microenvironment (TME) to a "hot" one by depleting immunosuppressive cells and enhancing tumor immunogenicity.

SUMMARY

This comprehensive review examines the immune microenvironment in PCa, focusing on the intricate interactions between immune and tumor cells in the TME. It highlights how TAMs, Tregs, cytotoxic T cells, and other immune cell types contribute to tumor progression or suppression and how PCa's low immunogenicity complicates immunotherapy.

KEY MESSAGES

The infiltration of cytotoxic CD8+ T cells and Th1 cells correlates with better outcomes, while elevated T regs and TAMs promote tumor growth, metastasis, and resistance. TANs and natural killer (NK) cells exhibit dual roles, with higher NK cell levels linked to better prognoses. Immune checkpoint molecules like PD-1, PD-L1, and TIM-3 are associated with advanced disease. Chemotherapy can improve tumor immunogenicity by depleting T regs and myeloid-derived suppressor cells, offering therapeutic promise.

Spinning Disk Confocal Microscopy for Optimized and Quantified Live Imaging of 3D Mitochondrial Network

Mitochondria are the energy factories of a cell, and depending on the metabolic requirements, the mitochondrial morphology, quantity, and membrane potential in a cell change. These changes are frequently assessed using commercially available probes. In this study, we tested the suitability of three commercially available probes-namely 5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolo-carbocyanine iodide (JC-1), MitoTracker Red CMX Rox (CMXRos), and tetramethylrhodamine methyl ester (TMRM)-for assessing the mitochondrial quantity, morphology, and membrane potential in living human mesoangioblasts in 3D with confocal laser scanning microscope (CLSM) and scanning disk confocal microscope (SDCM). Using CLSM, JC-1, and CMXRos-but not TMRM-uncovered considerable background and variation. Using SDCM, the background signal only remained apparent for the JC-1 monomer. Repetitive imaging of CMXRos and JC-1-but not TMRM-demonstrated a 1.5-2-fold variation in signal intensity between cells using CLSM. The use of SDCM drastically reduced this variation. The slope of the relative signal intensity upon repetitive imaging using CLSM was lowest for TMRM (-0.03) and highest for CMXRos (0.16). Upon repetitive imaging using SDCM, the slope varied from 0 (CMXRos) to a maximum of -0.27 (JC-1 C1). Conclusively, our data show that TMRM staining outperformed JC-1 and CMXRos dyes in a (repetitive) 3D analysis of the entire mitochondrial quantity, morphology, and membrane potential in living cells.

Straight to the point: targeted mRNA-delivery to immune cells for improved vaccine design

With the deepening of our understanding of adaptive immunity at the cellular and molecular level, targeting antigens directly to immune cells has proven to be a successful strategy to develop innovative and potent vaccines. Indeed, it offers the potential to increase vaccine potency and/or modulate immune response quality while reducing off-target effects. With mRNA-vaccines establishing themselves as a versatile technology for future applications, in the last years several approaches have been explored to target nanoparticles-enabled mRNA-delivery systems to immune cells, with a focus on dendritic cells. Dendritic cells (DCs) are the most potent antigen presenting cells and key mediators of B- and T-cell immunity, and therefore considered as an ideal target for cell-specific antigen delivery. Indeed, improved potency of DC-targeted vaccines has been proved in vitro and in vivo. This review discusses the potential specific targets for immune system-directed mRNA delivery, as well as the different targeting ligand classes and delivery systems used for this purpose.