The novel role of thymopentin in induction of maturation of bone marrow dendritic cells (BMDCs)

Repolarizing Tumor-Associated Macrophages and inducing immunogenic cell Death: A targeted liposomal strategy to boost cancer immunotherapy

Cancer immunotherapy has shown promise in treating various malignancies. However, the presence of an immunosuppressive tumor microenvironment (TME) triggered by M2 tumor-associated macrophages (TAMs) and the limited tumor cell antigenicity have hindered its broader application. To address these challenges, we developed DOX/R837@ManL, a liposome loaded with imiquimod (R837) and doxorubicin (DOX), modified with mannose-polyethylene glycol (Man-PEG). DOX/R837@ManL employed a mannose receptor (MRC1)-mediated targeting strategy, allowing it to accumulate selectively at M2 Tumor associated macrophages (TAMs) and tumor sites. R837, an immune adjuvant, promoted the conversion of immunosuppressive M2 TAMs into immunostimulatory M1 TAMs, and reshaped the immunosuppressive TME. Simultaneously, DOX release induced immunogenic cell death (ICD) in tumor cells and enhanced tumor cell antigenicity by promoting dendritic cells (DCs) maturation. Through targeted delivery, the synergistic action of R837 and DOX activated innate immunity and coordinated adaptive immunity, enhancing immunotherapy efficacy. In vivo experiments have demonstrated that DOX/R837@ManL effectively eliminated primary tumors and lung metastases, while also preventing tumor recurrence post-surgery. These findings highlighted the potential of DOX/R837@ManL as a promising strategy for cancer immunotherapy.

Yeast Expressed Hybrid Peptide CLP Abridged Pro-Inflammatory Cytokine Levels by Endotoxin Neutralization

The aim of this study was to apply a strategy to express a recombinant CLP peptide and explore its application as a product derived from natural compounds. The amphiphilic CLP peptide was hybridized from three parent peptides (CM4, LL37, and TP5) and was considered to have potent endotoxin-neutralizing activity with minimal cytotoxic and hemolytic activity. To achieve high secretion expression, an expression vector of pPICZαA-HSA-CLP was constructed by the golden gate cloning strategy before being transformed into Pichia pastoris and integrated into the genome. The recombinant CLP was purified through the Ni-NTA affinity chromatography and analyzed by SDS-PAGE and mass spectrometry. The Limulus amebocyte lysate (LAL) test exhibited that the hybrid peptide CLP inhibited lipopolysaccharides (LPS) in a dose-dependent manner and was significantly (p < 0.05) more efficient compared to the parent peptides. In addition, it essentially diminished (p < 0.05) the levels of nitric oxide and pro-inflammatory cytokines (including TNF-α, IL6, and IL-1β) in LPS-induced mouse RAW264.7 macrophages. As an attendant to the control and the parental peptide LL37, the number of LPS-induced apoptotic cells was diminished compared to the control parental peptide LL37 (p < 0.05) with the treatment of CLP. Consequently, we concluded that the hybrid peptide CLP might be used as a therapeutic agent.

Peptide nano-blanket impedes fibroblasts activation and subsequent formation of pre-metastatic niche

There is evidence to suggest that the primary tumor induces the formation of a pre-metastatic niche in distal organs by stimulating the production of pro-metastatic factors. Given the fundamental role of the pre-metastatic niche in the development of metastases, interruption of its formation would be a promising strategy to take early action against tumor metastasis. Here we report an enzyme-activated assembled peptide FR17 that can serve as a “flame-retarding blanket” in the pre-metastatic niche specifically to extinguish the “fire” of tumor-supportive microenvironment adaption. We show that the in-situ assembled peptide nano-blanket inhibits fibroblasts activation, suppressing the remodeling of the metastasis-supportive host stromal tissue, and reversing vascular destabilization and angiogenesis. Furthermore, we demonstrate that the nano-blanket prevents the recruitment of myeloid cells to the pre-metastatic niche, regulating the immune-suppressive microenvironment. We show that FR17 administration effectively inhibits the formation of the pulmonary pre-metastatic niche and postoperative metastasis, offering a therapeutic strategy against pre-metastatic niche formation.

Primary tumors “spread the spark” by establishing a pre-metastatic niche. Here the authors develop an in-situ assembled peptide FR17 to serve as a “flame-retarding blanket” to extinguish the “fire” of the pre-metastatic microenvironment.

Cell Senescence and Central Regulators of Immune Response

Pathways regulating cell senescence and cell cycle underlie many processes associated with ageing and age-related pathologies, and they also mediate cellular responses to exposure to stressors. Meanwhile, there are central mechanisms of the regulation of stress responses that induce/enhance or weaken the response of the whole organism, such as hormones of the hypothalamic-pituitary-adrenal (HPA) axis, sympathetic and parasympathetic systems, thymic hormones, and the pineal hormone melatonin. Although there are many analyses considering relationships between the HPA axis and organism ageing, we found no systematic analyses of relationships between the neuroendocrine regulators of stress and inflammation and intracellular mechanisms controlling cell cycle, senescence, and apoptosis. Here, we provide a review of the effects of neuroendocrine regulators on these mechanisms. Our analysis allowed us to postulate a multilevel system of central regulators involving neurotransmitters, glucocorticoids, melatonin, and the thymic hormones. This system finely regulates the cell cycle and metabolic/catabolic processes depending on the level of systemic stress, stage of stress response, and energy capabilities of the body, shifting the balance between cell cycle progression, cell cycle stopping, senescence, and apoptosis. These processes and levels of regulation should be considered when studying the mechanisms of ageing and the proliferation on the level of the whole organism.

The modulatory effect of crotoxin and its phospholipase A2 subunit from Crotalus durissus terrificus venom on dendritic cells interferes with the generation of effector CD4+ T lymphocytes

Dendritic Cells (DCs) direct either cellular immune response or tolerance. The crotoxin (CTX) and its CB subunit (phospholipase A₂) isolated from Crotalus durissus terrificus rattlesnake venom modulate the DC maturation induced by a TLR4 agonist. Here, we analyzed the potential effect of CTX and CB subunit on the functional ability of DCs to induce anti-ovalbumin (OVA) immune response. Thus, CTX and CB inhibited the maturation of OVA/LPS-stimulated BM-DCs from BALB/c mice, which means inhibition of costimulatory and MHC-II molecule expression and proinflammatory cytokine secretion, accompanied by high expression of ICOSL, PD-L1/2, IL-10 and TGF-β mRNA expression. The addition of CTX and CB in cultures of BM-DCs incubated with ConA or OVA/LPS inhibited the proliferation of CD3⁺ or CD4⁺T cells from OVA-immunized mice. In in vitro experiment of co-cultures of purified CD4⁺T cells of DO11.10 mice with OVA/LPS-stimulated BM-DCs, the CTX or CB induced lowest percentage of Th1 and Th2 and CTX induced increase of Treg cells. In in vivo, CTX and CB induced lower percentage of CD4⁺IFNγ⁺ and CD4⁺IL-4⁺ cells, as well as promoted CD4⁺CD25⁺IL-10⁺ population in OVA/LPS-immunized mice. CTX in vivo also inhibited the maturation of DCs. Our findings demonstrate that the modulatory action of CTX and CB on DCs interferes with the generation of adaptive immunity and, therefore contribute for the understanding of the mechanisms involved in the generation of cellular immunity, which can be useful for new therapeutic approaches for immune disorders.

The Efficacy and Safety of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Combined With Thymosin in Advanced Non-Small Cell Lung Cancer Patients Harboring Active Epidermal Growth Factor Receptor Mutations

Objective

To explore the efficacy and safety of EGFR-TKI combined with thymosin therapy in advanced non-small cell lung cancer (NSCLC) patients harboring active EGFR mutations.

Methods

Patients confirmed as advanced NSCLC with active EGFR mutations were recruited from August 2008 to July 2018 retrospectively. Patients treated with EGFR-TKI were classified as the EGFR-TKI group. And those received EGFR-TKI and thymosin therapy were designated as the EGFR-TKI plus thymosin group. The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall survival (OS), tumor response and adverse effects.

Results

The median PFS was significantly longer in EGFR-TKI plus thymosin group than that in EGFR-TKI group (14.4 months vs. 9.2 months; HR=0.433, 95% CI 0.322 - 0.582, P<0.0001). The median OS was also prolonged in EGFR-TKI plus thymosin group than that in EGFR-TKI group (29.5 months vs. 19.8 months; HR=0.430, 95% CI 0.319 - 0.580, P<0.0001). The objective response rate in EGFR-TKI plus thymosin group and EGFR-TKI group were 60.0% versus 60.8% (P=0.918). The disease control rate was 96.9% in EGFR-TKI plus thymosin group and 97.7% in EGFR-TKI group (P=1.000). There were no significant differences in adverse effects between the two groups. The number of CD3⁺T cells in peripheral blood decreased significantly after treatment including both CD3⁺CD4⁺T and CD3⁺CD8⁺T subsets in EGFR-TKI group, but not in EGFR-TKI plus thymosin group.

Conclusions

Combination of EGFR-TKI and thymosin can significantly prolong the PFS and OS compared with EGFR-TKI monotherapy without more adverse events, which offers a new strategy in clinic.

Biobased dynamic hydrogels by reversible imine bonding for controlled release of thymopentin

Thymopentin (TP5) is widely used in the treatment of autoimmune diseases, but the short in vivo half-life of TP5 strongly restricts its clinical applications. A series of blank and TP5 loaded hydrogels were synthesized via reversible dual imine bonding by mixing water soluble O-carboxymethyl chitosan (CMCS) with a dynamer (Dy) prepared from Jeffamine and benzene-1,3,5-tricarbaldehyde. TP5 release from hydrogels was studied at 37 °C under in vitro conditions. The molar mass of CMCS, drug loading conditions and drug content were varied to elucidate their effects on hydrogel properties and drug release behaviors. Density functional theory was applied to theoretically confirm the chemical connections between TP5 or CMCS with Dy. All hydrogels exhibited interpenetrating porous architecture with average pore size from 59 to 83 μm, and pH-sensitive swelling up to 10,000% at pH 8. TP5 encapsulation affected the rheological properties of hydrogels as TP5 was partially attached to the network via imine bonding. Higher TP5 loading led to higher release rates. Faster release was observed at pH 5.5 than at pH 7.4 due to lower stability of imine bonds in acidic media. Fitting of release data using Higuchi model showed that initial TP5 release was essentially diffusion controlled. All these findings proved that the dynamic hydrogels are promising carriers for controlled delivery of hydrophilic drugs, and shed new light on the design of drug release systems by both physical mixing and reversible covalent bonding.

Immunomodulatory Effect of Structurally Characterized Mushroom Sclerotial Polysaccharides Isolated from Polyporus rhinocerus on Bone Marrow Dendritic Cells

This study evaluated the immunomodulatory effects of two high-molecular-weight and structurally different mushroom polysaccharides, an alkali-soluble polysaccharide (mPRSon) and a water-soluble polysaccharide-protein complex (PRW), isolated previously from the sclerotia of Pleurotus rhinocerus, on the maturation of murine bone-marrow-derived dendritic cells (BMDCs). The effects of mPRSon and PRW on the expression of morphological change, surface molecules, phagocytic activity, and cytokine release in BMDCs were determined by flow cytometry and a mouse cytokine array. The results showed that both mPRSon and PRW could induce phenotypic and functional maturation of BMDCs. At the same time, mPRSon upregulated the expression of membrane phenotypic marker CD86 and PRW markedly upregulated CD40, CD80, and CD86. In addition, mPRSon could bind to the dectin-1 receptor and stimulate the release of MIP-1α, MIP-2, and IL-2, while PRW could bind to complement receptor 3 and toll-like receptor 2 with an upregulation of the expression of IL-2, IL-6, MIP-1α, MIP-2, RANTES, IL-12p40p70, IL-12p70, TIMP-1, IFN-γ, KC, MCP-1, and GCSF. The study provides additional information on how structural differences in sclerotial polysaccharides influence their immunomodulatory activities on BMDCs involving different PAMP receptors. It is anticipated that more understanding of the interactions between the sclerotial polysaccharides and their receptors in immune cells can facilitate their future application for cancer immunotherapy.

Maturation of dendritic cells in vitro and immunological enhancement of mice in vivo by pachyman- and/or OVA-encapsulated poly(d,l-lactic acid) nanospheres

Background

Poly lactide (PLA) was proved in the last years to be good for use in sustained drug delivery and as carriers for vaccine antigens. In our previous research, pachyman (PHY)-encapsulated PLA (PHYP) nanospheres were synthesized and their function of controlling drug release was demonstrated.

Purpose

In order to modify the fast drug-release rate of PHY when inoculated alone, the maturation of bone marrow dendritic cells (BMDCs) in vitro and their immunological enhancement in vivo were explored using PHYP nanospheres.

Methods

The maturation and antigen uptake of BMDCs were evaluated, both alone and with formulated antigen PHYP nanospheres, ie, ovalbumin (OVA)-loaded PHYP nanospheres, as an antigen delivery system, to investigate antigen-specific humoral and cellular immune responses.

Results

The results indicated that, when stimulated by PHYP, the BMDCs matured as a result of upregulated expression of co-stimulatory molecules; the mechanism was elucidated by tracing fluorescently labeled antigens in confocal laser scanning microscopy images and observing the uptake of nanospheres by transmission electron microscopy. It was further revealed that mice inoculated with OVA-PHYP had augmented antigen-specific IgG antibodies, increased cytokine secretion by splenocytes, increased splenocyte proliferation, and activation of cluster of differentiation (CD)4⁺ and CD8⁺ T cells in vivo. Elevated immune responses were produced by OVA-PHYP, possibly owing to the activation and maturation of dendritic cells (in draining lymph nodes).

Conclusion

It was corroborated that PHY- and/or OVA-encapsulated PLA nanospheres elicited prominent antigen-presenting effects on BMDCs and heightened humoral and cellular immune responses compared with other formulations.

Discrimination of the heterogeneity of bone marrow‑derived dendritic cells

The present study aimed to discriminate different subsets of cultured dendritic cells (DCs) to evaluate their immunological characteristics. DCs offer an important foundation for immunological studies, and mouse bone marrow (BM) cells cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) have been used extensively to generate CD11c⁺/major histocompatibility complex II⁺ BM-derived DCs (BMDCs). Immature DCs are considered to have strong migration and phagocytic antigen-capturing abilities, whereas mature DCs are thought to activate naive T cells and express high levels of costimulatory cytokines and adhesion molecules. In most culture systems, non-adherent cells are collected as mature and qualified DCs, and the remaining adherent cells are discarded. The output from GM-CSF cultures comprises mostly adherent cells, and only a small portion of them is non-adherent. This situation has resulted in ambiguities in the attempts to understand results from the use of cultured DCs. In the present study, DCs were divided into three subsets: i) Non-adherent cells; ii) adherent cells and iii) mixed cells. The heterogeneous features of cultured DCs were identified by evaluating the maturation status, cytokine secretion and the ability to activate allogeneic T cells according to different subsets. Results from the study demonstrated that BMDC culture systems were a heterogeneous group of cells comprising non-adherent cells, adherent cells, mixed cells and firmly adherent cells. Non-adherent cells may be used in future studies that require relatively mature DCs such as anticancer immunity. Adherent cells may be used to induce tolerance DCs, whereas mixed cells may potentiate either tolerogenicity or pro-tumorigenic responses. Firmly adherent cells were considered to have macrophage-like properties. The findings may aid in immunological studies that use cultured DCs and may lead to more precise DC research.

Murine bone marrow-derived DCs activated by porcine rotavirus stimulate the Th1 subtype response in vitro

Rotavirus (RV) infection causes acute, watery dehydrating diarrhea and even death in infants and other young animals, resulting in a severe economic burden; however, little is known about the innate immune mechanisms associated with RV infection. Dendritic cells (DCs), which are professional antigen-presenting cells (APCs), serve as a bridge connecting the innate and adaptive immune system. In this study, the interaction between murine bone marrow-derived DCs (BMDCs) and porcine rotavirus (PRV) was investigated in vitro. Upon stimulation, the expression levels of MHC-II, CD40, CD80, CD86 and CD83 in BMDCs increased in a time-dependent manner, indicating activation and maturation by PRV. In addition, up-regulated Toll-like receptor 2 (TLR2), TLR3 and NF-κB increased the production of interleukin-12 and interferon-γ. The PRV-stimulated BMDCs also showed increased stimulatory capacity in mixed lymphocyte reactions and promoted the Th1 subtype response.

The role of porcine reproductive and respiratory syndrome virus infection in immune phenotype and Th1/Th2 balance of dendritic cells

The aim of this study was to characterize the immune response of dendritic cells derived from monocytes (Mo-DCs) in the porcine peripheral blood following infection with porcine reproductive and respiratory syndrome virus (PRRSV). Viral load assays indicated that PRRSV efficiently infected Mo-DCs but failed to replicate, whereas PRRSV infection of Mo-DCs decreased the expression of SLA-I, SLA-II, CD80 and CD40 compared with those of mock Mo-DCs. Furthermore, we analyzed the cytokine profiles using quantitative RT-PCR and ELISA. Results indicated apparent changes in IL-10 and IL-12 p40 expression but not in IFN-γ and TNF-α among Mo-DCs infected with PRRSV and uninfected Mo-DCs. Additionally, flow cytometry analysis of the altered Mo-DCs together with IL-4 and GM-CSF induction for 7days revealed the typical morphology and phenotype with 91.73% purity before infection with PRRSV. Overall, our data demonstrate that PRRSV impaired the normal antigen presentation of Mo-DCs and led to inadequate adaptive immune response by down-regulating the expression of SLA-I,SLA-II, CD80 and CD40. Enhanced Th2 -type cytokine IL-10 secretion and reduced Th1-type cytokines IL-12p40,IFN-γ and TNF-α secretion results in Th1/Th2 imbalance.

Immune formulation-assisted conventional therapy on anti-infective effectiveness of multidrug-resistant Mycobacterium tuberculosis infection mice

OBJECTIVE

To study the effect of immune formulation-assisted conventional therapy on anti-infective ability of multidrug-resistant Mycobacterium tuberculosis infection mice.

METHODS

BALB/c mice were used as experimental animals, multidrug-resistant M. tuberculosis infection models were built, randomly divided into model group, moxifloxacin group, thymopentin group and combined treatment group and given corresponding drug intervention, and then colony numbers in the spleen and lung, T lymphocyte subset contents and programmed death-1 (PD-1) expression levels in peripheral blood were detected.

RESULTS

Colony numbers in lung and spleen of moxifloxacin group and thymopentin group were significantly lower than those of model group and colony numbers in lung and spleen of combined treatment group were significantly lower than those of moxifloxacin group and thymopentin group; contents of CD3(+)CD4(+)T cells, Th1 and Th17 in peripheral blood of moxifloxacin group and thymopentin group were higher than those of model group, and contents of CD3(+)CD8(+)T cells, Th2 and Treg were lower than those of model group; contents of CD3(+)CD4(+)T cells, Th1 and Th17 in peripheral blood of combined treatment group were higher than those of moxifloxacin group and thymopentin group, and contents of CD3(+)CD8(+)T cells, Th2 and Treg were lower than those of moxifloxacin group and thymopentin group; PD-1 expression levels on T lymphocyte, B lymphocyte and monocyte surface in peripheral blood of moxifloxacin group and thymopentin group were lower than those of model group, and PD-1 expression levels on T lymphocyte, B lymphocyte and monocyte surface in peripheral blood of combined treatment group were lower than those of moxifloxacin group and thymopentin group.

CONCLUSIONS

Immune formulation thymopentin can enhance the anti-infective ability of multidrug-resistant M. tuberculosis infection mice, decrease bacterial load in lung and spleen, and enhance immune function.

A novel role for RGMa in modulation of bone marrow-derived dendritic cells maturation induced by lipopolysaccharide

Repulsive guidance molecule a (RGMa) is known to mediate immune responses and has been indicated to modulates T cell activation and autoimmune diseases by dendritic cells (DCs), which hints its significant function in the latter cells. The aim of our study, therefore, was to evaluate the function of RGMa in DC maturation. We found that small interfering RNA (siRNA) successfully silenced the expression of RGMa in DCs. Even after LPS stimulation, RGMa-silenced DCs displayed an immature morphology, characterized by small, round cells with a few cell processes and organelles, and many pinocytotic vesicles. In the presence of LPS, RGMa siRNA transfection markedly reduced levels of CD80, CD86, CD40, and MHC II expression, as well as the secretion of IL-12p70 and TNF-α. With LPS treatment, RGMa siRNA-transfected DCs also showed increased levels of IL-10 and endocytosis. Moreover, in the presence of LPS, RGMa siRNA-transfected DCs displayed a low ability to induce T cell proliferation and differentiation, compared with negative control (NTi)-transfected or control DCs (p<0.05 for both). We conclude that after LPS stimulation, RGMa siRNA-transfected DCs show immunoregulatory and tolerogenic characteristics, which provides new insights into the immune system.