Induce Dendritic Cells Maturation Research Articles

Toll-Like Receptors Mediate Opposing Dendritic Cell Effects on Treg/Th17 Balance in Mice With Intracerebral Hemorrhage.

Dendritic cells (DCs) regulate the immune response associated with T lymphocytes, but their role in stroke remains unclear. In this study, we investigated the causal relationship between DCs and T-cell response in intracerebral hemorrhage (ICH) by focusing on TLRs (toll-like receptors) that may modulate the function of DCs. We studied the effects of TLR4, TLR2, and TLR9 on DC-mediated T-cell response and the outcomes of ICH using male C57BL/6 and CD11c-DTx (diphtheria toxin) receptor mice. We administered specific agents intraperitoneally or orally and evaluated the results using flow cytometry, real-time polymerase chain reaction, Western blotting, immunofluorescence staining, histopathology, and behavioral tests. TLR4 and TLR2 activation induces DC maturation and reduces the ratio of regulatory T to T-helper 17 cells in the brain and periphery after ICH. When either of these receptors is activated, it can worsen neuroinflammation and exacerbate ICH outcomes. TLR9 also promotes DC maturation, stabilizing the number of DCs, particularly conventional DCs. TLR9 has the opposite effects on regulatory T/T-helper 17 balance, neuroinflammation, and ICH outcomes compared with TLR4 and TLR2. Upon stimulation, TLR4 and TLR9 may achieve these effects through the p38-MAPK (p38-mitogen-activated protein kinase)/MyD88 (myeloid differentiation primary response gene 88) and indoleamine 2,3-dioxygenase 1 (IDO1)/GCN2 (general control nonderepressible 2) signaling pathways, respectively. DCs act as intermediaries for TLR-mediated T-cell response. TLR-mediated opposing effects of DCs on T-cell response may provide novel strategies to treat ICH.

PA28γ induces dendritic cell maturation and activates T-cell immune responses in oral lichen planus.

Oral lichen planus (OLP) is a common chronic inflammatory disease of the oral mucosa, the mechanism of its inflammatory progression has not yet been fully elucidated. PA28γ plays a significant role in a variety of immune-related diseases. However, the exact role of PA28γ in the pathogenesis of OLP remains unclear. Here, we demonstrated that PA28γ is overexpressed in epithelial cells and inflammatory cells of OLP tissues but has no significant relationship with OLP subtypes. Functionally, keratinocytes with high PA28γ expression could induce dendritic cell (DC) maturation and promote the T-cell differentiation into Th1 cells in response to the immune response. In addition, we found that a high level of PA28γ expression is associated with high numbers of infiltrating mature DCs and activated T-cells in OLP tissues. Mechanistically, keratinocytes with high PA28γ expression could promote the secretion of C-C motif chemokine (CCL)5, blocking CCL5 or/and its receptor CD44 could inhibit the induction of T-cell differentiation by keratinocytes with high PA28γ expression. In conclusion, we reveal that keratinocytes with high expression of PA28γ in OLP can induce DC maturation and promote T-cell differentiation through the CCL5-CD44 pathway, providing previously unidentified mechanistic insights into the mechanism of inflammatory progression in OLP.

Integrated Copper Nanomaterials‐Decorated Microsphere Photothermal Platform for Comprehensive Melanoma Treatment

Patients who undergo resection for melanoma face challenges, such as delayed healing and radiation dermatitis. Moreover, incomplete tumor resection is a key factor contributing to poor prognosis and increased recurrence rates. However, a therapeutic platform that can effectively prevent tumor recurrence and promote wound healing remains a challenge. Hence, a pioneering approach is presented using melanoma‐derived cancer cell membrane (CM) as a tumor antigen to encapsulate copper (Cu)‐based metal‐organic framework (MOF) nanomaterials to fabricate nanomaterials termed MOF@CM. Then MOF@CM is adsorbed onto polydopamine (PDA)‐modified poly lactic‐co‐glycolic acid (PLGA) porous microspheres (PLGA/PDA) to develop the copper nanomaterials‐decorated microspheres termed PLGA/PDA‐CCM (PLGA/PDA loaded with CM‐coated MOF). It exerts homologous tumor targeting and photothermal effects, inducing immunogenic cell death. Simultaneously, the sustained release of MOF@CM shows enhanced antigen presentation in dendritic cells (DCs) with the help of CpG, and induces DC maturation and activated immune responses, acting as an effective vaccine to prevent tumor recurrence. The platform harnesses the combined advantages of the local thermal effect and the presence of a Cu‐based MOF, which endow antibacterial properties and stimulate angiogenesis, thereby facilitating wound healing and mitigating radiation dermatitis. This integrated microsphere treatment platform represents a promising strategy for addressing melanoma.

Phototruncation cell tracking with near-infrared photoimmunotherapy using heptamethine cyanine dye to visualise migratory dynamics of immune cells

Noninvasive invivo cell tracking is valuable in understanding the mechanisms that enhance anti-cancer immunity. We have recently developed a new method called phototruncation-assisted cell tracking (PACT), that uses photoconvertible cell tracking technology to detect invivo cell migration. This method has the advantages of not requiring genetic engineering of cells and employing tissue-penetrant near-infrared light. We applied PACT to monitor the migration of immune cells between a tumour and its tumour-draining lymph node (TDLN) after near-infrared photoimmunotherapy (NIR-PIT). PACT showed a significant increase in the migration of dendritic cells (DCs) and macrophages from the tumour to the TDLN immediately after NIR-PIT. This migration by NIR-PIT was abrogated by inhibiting the sphingosine-1-phosphate pathway or Gαi signaling. These results were corroborated by intranodal immune cell profiles at two days post-treatment; NIR-PIT significantly induced DC maturation and increased and activated the CD8+ T cell population in the TDLN. Furthermore, PACT revealed that NIR-PIT significantly enhanced the migration of CD8+ T cells from the TDLN to the tumour four days post-treatment, which was consistent with the immunohistochemical assessment of tumour-infiltrating lymphocytes and tumour regression. Immune cells dramatically migrated between the tumour and TDLN following NIR-PIT, indicating its potential as an immune-stimulating therapy. Also, PACT is potentially applicable to a wide range of immunological research. This work was supported by the Intramural Research Program of the National Institutes of Health, National Cancer Institute, Centre for Cancer Research (grant number: ZIA BC011513 and ZIA BC011506).

Exosomes Derived from Heat-shocked Tumor Cells Promote In vitro Maturation of Bone Marrow-derived Dendritic Cells.

Dendritic cells (DCs), professional antigen-presenting cells that process and deliver antigens using MHC II/I molecules, can be enhanced in numerous ways. Exosomes derived from heat-shocked tumor cells (HS-TEXs) contain high amounts of heat-shock proteins (HSPs). HSPs, as chaperons, can induce DC maturation. This study aimed to investigate whether HS-TEXs can promote DC maturation. To generate DC, bone marrow-derived cells were treated with Interleukin-4 and GM-CSF. Exosomes were isolated from heat-treated CT-26 cells. The expression level of HSP in exosomes was checked by western blot and the increase in the expression of this protein was observed. Then, HS-TEXs were co-cultured with iDCs to determine DC maturity, and then DCs were co-cultured with lymphocytes to determine DC activity. Our results showed that DCs treated with HS-TEXs express high levels of molecules involved in DC maturation and function including MHCII, CD40, CD83, and CD86. HS-TEXs caused phenotypic and functional maturation of DCs. In addition, flow cytometric results reflected a higher proliferative response of lymphocytes in the iDC / Tex + HSP group. HS-TEXs could be used as a strategy to improve DC maturation and activation.

LTX-315 triggers anticancer immunity by inducing MyD88-dependent maturation of dendritic cells.

LTX-315 is a synthetic cationic oncolytic peptide with potent anticancer activity but limited toxicity for non-malignant cells. LTX-315 induces both immunogenic tumor cell death and generation of tumor-specific immune responses in multiple experimental tumor models. Given the central role of dendritic cell (DC) maturation in the induction of antigen-specific immunity, we investigated the effect of LTX-315 treatment on the maturation of tumor-infiltrating DCs (TiDCs) and the generation of anti-melanoma immunity. We found that LTX-315 treatment induces the maturation of DCs, both indirectly through the release of cancer cell-derived damage-associated molecular patterns (DAMPs)/alarmins and nucleic acids (DNA and RNA) capable of triggering distinct Toll-like receptor (TLR) signaling, and, directly by activating TLR7. The latter results in the ignition of multiple intracellular signaling pathways that promotes DC maturation, including NF-κB, mitogen activated protein kinases (MAPKs), and inflammasome signaling, as well as increased type 1 interferon production. Critically, the effects of LTX-315 on DCs the consequent promotion of anti-melanoma immunity depend on the cytosolic signal transducer myeloid differentiation response gene 88 (MyD88). These results cast light on the mechanisms by which LTX-315 induces DC maturation and hence elicits anticancer immunity, with important implications for the use of LTX-315 as an anticancer immunotherapeutic.

Phenotypic features of dendritic cells when using different modes of their stimulated maturation

Monocyte-derived dendritic cells (DCs) can be used for cell immunotherapy of cancer. In most cases, mature DCs, loaded with tumor-associated antigens, are used for immune therapy. The functionality of DCs for immunotherapy substantially depends on their immunophenotype and secretory profile, which are established after DCs maturation. The purpose of this research was to explore the phenotype of DCs after using various approaches for stimulation of their maturation.Maturation of DCs was stimulated by pro-inflammatory cytokines and their mixtures, or by ligands to the TLRs of DCs. DCs were stimulated by the following means: TNF; poly I:C; LPS; cytokine cocktail (TNF + IL-1 + IL-6 + PGE2); the cocktail mixed with poly I:C; and melanoma cells lysate. Forty-eight hours after stimulation, the expression of DCs’ receptors involved into their interaction with T cells, was evaluated by flow cytometry. Moreover, the secretion of IL-12 (activator of T cell response) and IL-10 (inhibitor of T cell response) was estimated by ELISA technique.We have shown that, following stimulation with cytokine cocktail, the DCs exhibit highest expression of receptors, which are necessary for interaction with T cells and for activation of T cell mediated immune response, i.e., antigen-presenting receptors (HLA-DR), co-stimulatory receptors (CD83, CD40, CD86), and receptors controlling the migration of DCs to lymph nodes (CCR7). Moreover, the cocktail-stimulated DCs intensively secrete both IL-12 and IL-10. The stimulatory effect of TNF and poly I:C proved to be moderate: the expression of most receptors was significantly lower than after using the cocktail; no significant differences from control (in absence of induced maturation) in IL-12 secretion were detected. LPS and melanoma cell lysate did not affect both expression of receptors and secretory profile of DCs. Addition of poly I:C to the cytokine cocktail did not affect the receptor expression, but significantly increased the secretion of both proinflammatory IL-12 and anti-inflammatory IL-10.The results of experiments demonstrate that the mixture of cytokine cocktail and poly I:C seems to be the most effective tool for stimulation of DCs maturation. However, further experiments are required to compare the functionality of DCs when using different tools for induced DC maturation.

Antitumor activity of pegylated human interferon β as monotherapy or in combination with immune checkpoint inhibitors via tumor growth inhibition and dendritic cell activation

Type I interferons (IFN), especially human IFN alpha (IFNα), have been utilized for antitumor therapy for decades. Human interferon beta (IFNβ) is rarely used for cancer treatment, despite advantages over IFNα in biological activities such as tumor growth inhibition and dendritic cell (DC) activation. The utilization of pegylated human IFNβ (PEG-IFNβ), as monotherapy or in combination with immune checkpoint inhibitors (ICIs) was evaluated in this study through in vivo efficacy studies in syngeneic mouse melanoma, non-small cell lung cancer (NSCLC), and colon adenocarcinoma (COAD) models resistant to immune checkpoint inhibitors (ICIs). In vitro comparative study of PEG-IFNβ and pegylated IFNα-2b was performed in terms of tumor growth inhibition against human melanoma, NSCLC and COAD cell lines and activation of human monocyte-derived DCs (MoDCs). Our data demonstrate that the in vivo antitumor effects of PEG-IFNβ are partially attributable to tumor growth-inhibitory effects and DC-activating activities, superior to pegylated IFNα-2b. Our findings suggest that utilizing PEG-IFNβ as an antitumor therapy can enhance the therapeutic effect of ICIs in ICI-resistant tumors by directly inhibiting tumor growth and induction of DC maturation.

Application of microneedles combined with dendritic cell-targeted nanovaccine delivery system in percutaneous immunotherapy for triple-negative breast cancer

This work aims at developing a strategy to activate the antigen-presenting cells to enhance the effect of immunotherapy in triple-negative breast cancer (TNBC) through the dissolving microneedle patch (DMNP). In present study, mannosylated chitosan (MCS) nanoparticles (NPs) were designed to target dendritic cells (DCs), and the immunotherapy effect was enhanced by the adjuvant Bacillus Calmette–Guerin polysaccharide (BCG-PSN), achieving the purpose of transdermal immunotherapy for TNBC. Vaccination studies with mice demonstrated that MCS NPs effectively induce DCs maturation in the tumor-draining lymph nodes to stimulate strong immune responses in TNBC. Overall, chitosan-based DMNPs with complex adjuvant constituted a new potent transdermal vaccine delivery platform capable of exploiting more DCs in the skin for effective immunization.

Modified Rice Bran Arabinoxylan by Lentinus edodes Mycelial Enzyme as an Immunoceutical for Health and Aging-A Comprehensive Literature Review.

Rice bran arabinoxylan compound (RBAC) is derived from defatted rice bran enzymatically treated with Lentinus edodes mycelium. This review explores biologically active compounds and mechanisms of action that support RBAC as an immunomodulating nutraceutical in generally healthy and/or aging individuals. Thirty-seven (n = 37) primary research articles fulfilled the selection criteria for review. Most research is based on Biobran MGN-3, which consists of complex heteropolysaccharides with arabinoxylan as its primary structure while also containing galactan and glucan. RBAC was found to invoke immunological activities through direct absorption via the digestive tract and interaction with immune cells at the Peyer's patches. RBAC was shown to promote innate defence by upregulating macrophage phagocytosis and enhancing natural killer cell activity while lowering oxidative stress. Through induction of dendritic cell maturation, RBAC also augments adaptive immunity by promoting T and B lymphocyte proliferation. RBAC acts as an immunomodulator by inhibiting mast cell degranulation during allergic reactions, attenuating inflammation, and downregulating angiogenesis by modulating cytokines and growth factors. RBAC has been shown to be a safe and effective nutraceutical for improving immune health, notably in aging individuals with reduced immune function. Human clinical trials with geriatric participants have demonstrated RBAC to have prophylactic benefits against viral infection and may improve their quality of life. Further research should explore RBAC's bioavailability, pharmacodynamics, and pharmacokinetics of the complex heteropolysaccharides within. Translational research to assess RBAC as a nutraceutical for the aging population is still required, particularly in human studies with larger sample sizes and cohort studies with long follow-up periods.

Toll-like receptor 4 and Syk kinase shape dendritic cell-induced immune activation to major house dust mite allergens.

House dust mite (HDM) is a major cause of respiratory allergic diseases. Dendritic cells (DCs) play a central role in orchestrating adaptive allergic immune responses. However, it remains unclear how DCs become activated by HDM. Biochemical functions of the major HDM allergens Der p 1 (cysteine protease) and Der p 2 (MD2-mimick) have been implicated to contribute to DC activation. We investigated the immune activating potential of HDM extract and its major allergens Der p 1 and Der p 2 using monocyte-derived DCs (moDCs). Maturation and activation markers were monitored by flow cytometry and cytokine production by ELISA. Allergen depletion and proteinase K digestion were used to investigate the involvement of proteins, and in particular of the major allergens. Inhibitors of spleen tyrosine kinase (Syk), Toll-like receptor 4 (TLR4) and of C-type lectin receptors (CLRs) were used to identify the involved receptors. The contribution of endotoxins in moDC activation was assessed by their removal from HDM extract. HDM extract induced DC maturation and cytokine responses in contrast to the natural purified major allergens Der p 1 and Der p 2. Proteinase K digestion and removal of Der p 1 or Der p 2 did not alter the immune stimulatory capacity of HDM extract. Antibodies against the CLRs Dectin-1, Dectin-2, and DC-SIGN did not affect cytokine responses. In contrast, Syk inhibition partially reduced IL-6, IL-12 and completely blocked IL-10. Blocking TLR4 signaling reduced the HDM-induced IL-10 and IL-12p70 induction, but not IL-6, while endotoxin removal potently abolished the induced cytokine response. Our data strongly suggest that HDM-induced DC activation is neither dependent on Der p 1 nor Der p 2, but depend on Syk and TLR4 activation, which might suggest a crosstalk between Syk and TLR4 pathways. Our data highlight that endotoxins play a potent role in immune responses targeting HDM.

Oncolytic attenuated measles virus encoding NY-ESO-1 induces HLA I and II presentation of this tumor antigen by melanoma and dendritic cells.

Antitumor virotherapy stimulates the antitumor immune response during tumor cell lysis induced by oncolytic viruses (OVs). OV can be modified to express additional transgenes that enhance their therapeutic potential. In this study, we armed the spontaneously oncolytic Schwarz strain of measles viruses (MVs) with the gene encoding the cancer/testis antigen NY-ESO-1 to obtain MVny. We compared MV and MVny oncolytic activity and ability to induce NY-ESO-1 expression in six human melanoma cell lines. After MVny infection, we measured the capacity of melanoma cells to present NY-ESO-1 peptides to CD4 + and CD8 + T cell clones specific for this antigen. We assessed the ability of MVny to induce NY-ESO-1 expression and presentation in monocyte-derived dendritic cells (DCs). Our results show that MVny and MV oncolytic activity are similar with a faster cell lysis induced by MVny. We also observed that melanoma cell lines and DC expressed the NY-ESO-1 protein after MVny infection. In addition, MVny-infected melanoma cells and DCs were able to stimulate NY-ESO-1-specific CD4 + and CD8 + T cells. Finally, MVny was able to induce DC maturation. Altogether, these results show that MVny could be an interesting candidate to stimulate NY-ESO-1-specific T cells in melanoma patients with NY-ESO-1-expressing tumor cells.

Melanin-Based Immunoregulatory Nanohybrids Enhance Antitumor Immune Responses in Breast Cancer Mouse Model.

Natural melanin nanoparticles (MNPs) have demonstrated a potential for eliciting antitumor immune responses through inducing immunogenic cell death (ICD); however, the tumor microenvironment (TME) has been shown to inhibit T cell-mediated antitumor immunity. To address this challenge, we designed TME-responsive biodegradable melanin/MnOx nanohybrids via a biomineralization process. Under near-infrared (NIR) light irradiation, the photothermal property of melanin/MnOx nanohybrids triggers ICD and release of tumor-associated antigens (TAAs), while Mn2+ and TAAs induce dendritic cell (DC) maturation to provoke immune responses. Furthermore, the immunoregulatory properties of the nanohybrids themselves are exploited to reshape immunosuppressive TME and downregulate PD-L1 through alleviation of the hypoxic and acidic TME. Although MNPs demonstrate higher photothermal killing efficiency than the nanohybrids in vitro due to their superior photothermal effect, the melanin/MnOx nanohybrids exhibit significantly enhanced antitumor and antimetastatic effects in vivo, benefiting from their ability to reverse immunosuppression and induce DC maturation. Transcriptomics analysis confirmed the successful activation of immune responses. This work presents a promising approach for immunomodulation-enhanced cancer therapy through the intrinsic properties of melanin/MnOx nanohybrids.

Probiotic-derived exopolysaccharide interferes with T H2 priming and inhibits allergic inflammation

Abstract Allergic asthma is an increasing burden in industrialized countries, where treatments are limited to targeting symptoms and end-stage effectors rather than root causes. In recent years, the use of prophylactic, inhaled probiotic cocktails has shown promise in preventing allergic asthma. However, the mechanisms by which such probiotics prevent allergic symptoms and the exact bacterial product(s) responsible for probiotic activity remain to be elucidated. In this study, we focused on exopolysaccharide (EPS) from Bacillus subtilis, a ubiquitous soil bacterium that is commonly found as a dietary supplement. We found that in a mouse model of allergic airway disease, EPS treatment, prior to allergic sensitization and challenge, limits lung mucus hypersecretion and eosinophilia. Furthermore, EPS treatment inhibited accumulation of T H2, but not T H1 and T H17 subsets. To determine whether EPS was affecting T H2 cell priming by dendritic cells (DCs), we compared the composition and phenotype of DCs in the lung and mediastinal lymph nodes (medLN) after EPS treatment. Surprisingly, pre-treatment with EPS induced DC maturation as measured by an increase in costimulatory molecules and a decrease in the ability to uptake allergen and migrate to the medLN. DC maturation by EPS was TLR4-dependent, as TLR4 KO DCs did not respond to EPS. Together, our data suggest that EPS inhibits allergic sensitization by inducing DC maturation prior to allergen exposure, thereby leading to decreased T H2 priming and allergic inflammation. Thus, we provide a potential mechanism by which inhalation of a single probiotic-derived molecule can prevent the development of allergic inflammation. Supported by grants from NIH (3R01 AI125644-05S1, 1F31 HL156659-01A1)

Interferon-beta mediated STAT4up-regulation are distinct in the ex vivohuman CD4 +T-cells priming dendritic cells

Abstract STAT4 (Signal Transducer Activator of Transcription factor 4) polymorphisms are risk factors contributed to autoimmune disease. While STAT4 has a dominant role in promoting interferon-gamma (IFN-g) production in T and NK cells, its existence and function exert in human dendritic cells (DCs) are still unknown. To characterize the STAT4 expression in human peripheral DCs, we isolated DCs from buffy coat of health blood donors (n = 4). The ex vivo DCs were enriched and sorted into 3 subtypes including plasmacytoid DCs (pDCs, CD123 +), CD8 +T-cells priming DC (cDC1, CLEC9A +), and CD4 +T-cells priming DC (cDC2/3, CD1c +) through negative selection bead and flow cytometry. The presence of STAT4 as well as its potential target genes (interleukin-12, IL-12 and interleukin-23, IL-23) expression were examined in IFN-beta induced DCs maturation compared to immature DCs, using Real-Time PCR. We found the proportion of DCs subsets in peripheral mononuclear cells which are 0.05%, 0.02% and 0.3% for pDC, cDC1 and cDC2/3, respectively. The IFN-beta enhanced DC maturation markers (HLA-DR +CD86 +), especially in cDC2/3. Interestingly, up-regulated STAT4 expression (2.5-fold) were significantly prominent in mature cDC2/3 compared to immature (p < 0.01), while IFN-beta showed no influence on STAT4 expression in the cDC1 and pDC (p > 0.05). Interestingly, elevated IL-12 and IL-23 expression were significantly observed in activated cDC2/3 (p < 0.05). Further study to investigate the role of STAT4 in human cDC2/3 are needed. Our result firstly discover the existing of STAT4 expression in the ex vivo peripheral human DC. Supported by Chulalongkorn University (Fundamental Fund, CU_FRB65_hea (84)_179_37_09).

Nocardia rubra cell-wall skeleton activates an immune response in cervical tissue via stimulating FPR3 to enhance dendritic cell-mediated Th1 differentiation.

Nocardia rubra cell wall skeleton (Nr-CWS) has proven to be a successful medicine for therapy of cervical human papillomavirus infection. The mechanism of action of Nr-CWS is unclear but may involve a stimulatory effect on the host immune system. We previously found that CD4+ T cells were increased in cervical tissue after Nr-CWS treatment. Microarray data from these cervical tissues revealed the significant upregulation of formylated peptide receptor 3 (FPR3). This study aimed to explore the role of Nr-CWS in immunomodulatory based on these findings. Examination of CD4+ T cell subsets in cervical tissue from patients who received Nr-CWS revealed substantial increases in Th1 cytokines and transcription factors. The regulatory effects of Nr-CWS on the function and phenotype of dendritic cells (DCs) were assessed in comparison with the traditional DC maturation inducer lipopolysaccharide (LPS). Similar to LPS, Nr-CWS potently induced DC maturation and interleukin-12 (IL-12) secretion. Differentiation of T cells induced by Nr-CWS stimulated DCs was assessed using the mixed lymphocyte reaction assay. Significant differentiation towards Th1 was evident. Finally, FPR3 expression in DCs in response to Nr-CWS and LPS was measured. Nr-CWS potently upregulated FPR3 expression, while the LPS did not. Silencing FPR3 in DCs reduced Nr-CWS-induced IL-12 production and Th1 cell polarization in co-cultured T cells. The collective findings indicate that Nr-CWS may target FPR3 on the surface of DC cells and activate a Th1-type immune response. The findings clarify the basis of the antiviral immune effects of Nr-CWS on human papillomavirus.

Severe acute respiratory syndrome coronavirus 2 virus-like particles induce dendritic cell maturation and modulate T cell immunity.

Dendritic cells (DCs) are professional antigen-presenting cells that play an important role in both innate and acquired immune responses against pathogens. However, the role of DCs in coronavirus disease 2019 (COVID-19) is unclear. Virus-like particles (VLPs) that structurally mimic the original virus are one of the candidates COVID-19 vaccines. In the present study, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) VLPs were used as an alternative to live virus to evaluate the interaction of the virus with DCs. The results revealed that SARS-CoV-2 VLPs induced DC maturation by augmenting cell surface molecule expression (CD80, CD86, and major histocompatibility complex class II (MHC-II)) and inflammatory cytokine production (tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-12p70) in DCs via the mitogen-activated protein kinase and nuclear factor-κB signaling pathways. In addition, mature DCs induced by SARS-CoV-2 VLPs promoted T cell proliferation, which was dependent on VLPs concentration. Our results suggest that SARS-CoV-2 VLPs regulate the immune response by interacting with DCs. These findings will improve the understanding of SARS-CoV-2 pathogenesis and SARS-CoV-2 vaccine development.

Development and characterization of DEC-205 receptor targeted Potentilla anserina L polysaccharide PLGA nanoparticles as an antigen delivery system to enhance in vitro and in vivo immune responses in mice

Potentilla anserina L polysaccharide (PAP) is known to regulate immunity. Poly(lactic-co-glycolicacid) (PLGA) is a type of drug carrier with biocompatibility and biodegradable USFDA approved polymer, which possesses the advantages of high safety and good sustained-release effect. The DEC205 receptor, a type I membrane protein, is widely distributed on the surface of macrophages and dendritic cells (DCs) and plays a key role in antigen recognition and presentation. In this study, we prepared Potentilla anserina L polysaccharide PLGA nanoparticles targeting DEC205 receptor (DEC205-PAPP) and characterized the nanoparticles with regards to their effects on immune activation in vitro and in vivo. In vitro, DEC205-PAPP promoted the uptake activity of macrophages and increased the secretion of NO and cytokines (IFN-γ, IL-4, IL-6, and GM-CSF), up-regulated the expression of CD80+, CD86+. In vivo, DEC205-PAPP elevated the immune organ index, induced DC maturation, promoted T lymphocyte proliferation and differentiation, and increased the levels of antigen-specific IgG antibody and cytokines (IFN-γ, IL-4), which prolonged the residence time of the OVA antigen in the immune organs and the lymph nodes. In conclusion, DEC205-PAPP had a slow-release effect, induced humoral and cellular immune responses, and could potentially be used as an effective antigen-targeted delivery system.

RECQL4 Remodels the Tumor Immune Microenvironment via the cGAS-STING Pathway in Hepatocellular Carcinoma

<h3>Purpose/Objective(s)</h3> RECQL4 was considered a susceptible target for cancer therapy by playing diverse roles in the maintenance of genomic stability. Understanding more about the molecular characteristics of RECQL4 enables the better selection of HCC patients who would derive benefit from radiation therapy (RT) combined with immune checkpoint immunotherapies (ICIs). <h3>Materials/Methods</h3> We collected RNA sequencing data of 1175 HCC and 767 adjacent non-tumor tissues from 5 cohorts, followed by comprehensive evaluation of the expression patterns and multi-omics characteristics of RECQL4. Then, the expression of RECQL4 was systematically associated with HCC genomic instability and tumor microenvironment (TME) with multi-omics data and multicolor immunofluorescence staining. cGAS^−/− and STING^−/- mice were used to determine the relation of RECQL4 and cGAS-STING signaling pathway in HCC in vivo. Finally, clinical and pathologic data were collected retrospectively on HCC patients at the Zhongshan Hospital of Fudan University and associations with survival were determined. <h3>Results</h3> We found that RECQL4 was specifically overexpressed in HCC and significantly associated with a poor prognosis. The CNV results showed RECQL4 mutations was mainly caused by 8q24 and the expression was positive correlation with CNV burden. Moreover, RECQL4 expression was significantly and negatively correlated with the infiltrating levels of dendritic cells (DCs) and CD8 + T cells, which means high RECQL4 designed a non-inflamed TME. Low RECQL4 induces DCs maturation and antigen presentation by triggering the cGAS-STING pathway, and further activates CD8 + T cell-mediated the adaptive immunity. The result was further confirmed in RT combined with ICIs of HCC, which suggests that low RECQL4 bridges the DNA damaging capacity of RT with the CD8+ cytotoxic T cell-mediated destruction of cancer through innate immune signaling cGAS–STING to make the combined therapy better efficacy. Retrospective analysis also showed that HCC patients with low RECQL4 expression were more sensitive to RT with ICIs. <h3>Conclusion</h3> RECQL4 mediates a non-inflamed TME by regulating the cGAS-STING pathway on immune cells in HCC. HCC patients with low RECQL4 could derive response and benefit from several treatment options. RECQL4 serves as a new target for HCC radiotherapy combined with immunotherapy.

Ultrasound improved immune adjuvant delivery to induce DC maturation and T cell activation.

Tumor immunotherapy has emerged as a promising approach to tumor treatment. Currently, immune adjuvant-based therapeutic modalities are rarely curative in solid tumors owing to challenges including the low permeability and extremely poor water solubility of these adjuvants, limiting their ability to effectively promote dendritic cell (DC) maturation. Herein, we employed ultrasound-mediated cavitation (UMC) to promote the delivery of Toll-like receptor agonist (R837)-loaded pH-responsive liposomes (PEOz-Lip@R837) to tumors. The tumor-associated antigens (TAAs) produced by UMC treatment exhibited vaccinal activity, particularly in the presence of immune adjuvants, together promoting the maturation of DC and inducing cytokine production. Importantly, UMC can down-regulate immune checkpoint molecules, like Cd274, Foxp3 and Ctla4, synergistically stimulating the activation and proliferation of T cells in the body to facilitate tumor treatment. This UMC-enhanced PEOz-Lip@R837 approach was able to induce a robust antitumor immune response capable of arresting primary and distant tumor growth, while also developing immunological memory, protecting against tumor rechallenge following initial tumor clearance. Overall, these results highlight a promising UMC- and pH-sensitive immune adjuvant delivery-based treatment for tumors with the potential for clinical application.