Correlation between MDSC and Immune Tolerance in Transplantation: Cytokines, Pathways and Cell-cell Interaction

Immunotherapy and the ovarian cancer microenvironment: Exploring potential strategies for enhanced treatment efficacy

Despite progress in cancer immunotherapy, ovarian cancer (OC) prognosis continues to be disappointing. Recent studies have shed light on how not just tumour cells, but also the complex tumour microenvironment, contribute to this unfavourable outcome of OC immunotherapy. The complexities of the immune microenvironment categorize OC as a 'cold tumour'. Nonetheless, understanding the precise mechanisms through which the microenvironment influences the effectiveness of OC immunotherapy remains an ongoing scientific endeavour. This review primarily aims to dissect the inherent characteristics and behaviours of diverse cells within the immune microenvironment, along with an exploration into its reprogramming and metabolic changes. It is expected that these insights will elucidate the operational dynamics of the immune microenvironment in OC and lay a theoretical groundwork for improving the efficacy of immunotherapy in OC management.

Nanobodies in cytokine‑mediated immunotherapy and immunoimaging (Review)

Cytokines are the main regulators of innate and adaptive immunity, mediating communications between the cells of the immune system and regulating biological functions, including cell motility, differentiation, growth and apoptosis. Cytokines and cytokine receptors have been used in the treatment of tumors and autoimmune diseases, and to intervene in cytokine storms. Indeed, the use of monoclonal antibodies to block cytokine‑receptor interactions, as well as antibody‑cytokine fusion proteins has exhibited immense potential for the treatment of tumors and autoimmune diseases. Compared with these traditional types of antibodies, nanobodies not only maintain a high affinity and specificity, but also have the advantages of high thermal stability, a high capacity for chemical manipulation, low immunogenicity, good tissue permeability, rapid clearance and economic production. Thus, nanobodies have extensive potential for use in the diagnosis and treatment of cytokine‑related diseases. The present review summarizes the application of nanobodies in cytokine‑mediated immunotherapy and immunoimaging.

The recent progress of myeloid-derived suppressor cell and its targeted therapies in cancers

Myeloid-derived suppressor cells (MDSCs) are an immature group of myeloid-derived cells generated from myeloid cell precursors in the bone marrow. MDSCs appear almost exclusively in pathological conditions, such as tumor progression and various inflammatory diseases. The leading function of MDSCs is their immunosuppressive ability, which plays a crucial role in tumor progression and metastasis through their immunosuppressive effects. Since MDSCs have specific molecular features, and only a tiny amount exists in physiological conditions, MDSC-targeted therapy has become a promising research direction for tumor treatment with minimal side effects. In this review, we briefly introduce the classification, generation and maturation process, and features of MDSCs, and detail their functions under various circumstances. The present review specifically demonstrates the environmental specificity of MDSCs, highlighting the differences between MDSCs from cancer and healthy individuals, as well as tumor-infiltrating MDSCs and circulating MDSCs. Then, we further describe recent advances in MDSC-targeted therapies. The existing and potential targeted drugs are divided into three categories, monoclonal antibodies, small-molecular inhibitors, and peptides. Their targeting mechanisms and characteristics have been summarized respectively. We believe that a comprehensive in-depth understanding of MDSC-targeted therapy could provide more possibilities for the treatment of cancer.

The paradoxical role of MDSCs in inflammatory bowel diseases: From bench to bedside

Myeloid-derived suppressor cells (MDSCs) are a group of bone marrow derived heterogeneous cells, which is known for their immunosuppressive functions especially in tumors. Recently, MDSCs have receiving increasing attention in pathological conditions like infection, inflammation and autoimmune diseases. Inflammatory bowel diseases (IBD) are a series of immune-dysfunctional autoimmune diseases characterized by relapsing intestinal inflammation. The role of MDSCs in IBD remains controversial. Although most studies in vitro demonstrated its anti-inflammatory effects by inhibiting the proliferation and function of T cells, it was reported that MDSCs failed to relieve inflammation but even promoted inflammatory responses in experimental IBD. Here we summarize recent insights into the role of MDSCs in the development of IBD and the potential of MDSCs-targeted therapy.

JAK2 gene knockout inhibits corneal allograft rejection in mice by regulating dendritic cell-induced T cell immune tolerance

Corneal allograft rejection can be seen in some patients after corneal transplantation. The present study intends to investigate whether JAK2 gene knockout affects corneal allograft rejection through regulation of dendritic cells (DCs)-induced T cell immune tolerance. In order to identify the target gene related to corneal allograft rejection, high-throughput mRNA sequencing and bioinformatics analysis were performed. JAK2 knockout mice were constructed and subjected to corneal allograft transplantation. The incidence of immune rejection was observed, the percentage of CD4⁺ T cells was detected, and the expression of Th1 cytokine interferon γ (IFN-γ) was determined. Flow cytometry and ELISA were performed to analyze the effects of JAK2 gene knockout on bone marrow-derived DCs (BMDCs). JAK2 was the target gene related to corneal allograft rejection. JAK2 gene knockout contributed to significantly prolonged survival time of corneal grafts in mice and inhibited corneal allograft rejection. The in vitro cell experiment further confirmed that JAK2 gene knockout contributed to the inactivation of CD4⁺ T cells and induced IFN-γ expression, accompanied by inhibition of DC immune function, development, maturation, and secretion of inflammatory cytokines. Collectively, JAK2 gene knockout inactivates CD4⁺ T cells to decrease IFN-γ expression, as well as inhibits DC development, maturation, and secretion of inflammatory cytokines, thereby reducing corneal allograft rejection.

Ginsenosides Regulates Innate Immunity to Affect Immune Microenvironment of AIH Through Hippo-YAP/TAZ Signaling Pathway

Autoimmune hepatitis (AIH) is characterized by chronic progressive liver inflammatory, but there is still no safe and effective medicine. Therefore, glucocorticoid remains the top choice for AIH treatment. In previous studies, it has been confirmed that ginsenosides (GSS) can produce glucocorticoid-like effects and therapeutic effects on various autoimmune diseases. However, the mechanism of GSS for AIH remains unclear. As an important part of the innate immune system, bone marrow-derived suppressor cells (MDSC) have been identified as an important driver of follow-up acquired immune response in many autoimmune diseases, including AIH. Herein, it was found out that GSS intervention can be effective in regulating the immune microenvironment and liver impairment induced by Con A in AIH mice. In vitro, the MDSCs derived from healthy mice and the T cells deried from AIH mice were co-cultured. Then, different drugs were intervened with to explore the therapeutic mechanism. Besides, the proliferation and differentiation of MDSCs and T cells were analyzed by flow cytometry, while GR, Hippo-YAP signal pathway and the expression of MDSC-related genes and proteins were detected through qRT-PCR and Western Blot. The changes in NO and ROS levels were further analyzed. The trend of related cytokines expression (IFN- γ, TGF- β, IL-10, IL-6, IL-17) was detected by ELISA. Furthermore, an analysis was conducted as to the ALT and liver pathology of mice for evaluating the liver function of mice. It was discovered that MDSCs proliferation was inhibited, and that T cells tended to differentiate into Th17 rather than Treg in AIH mice. Moreover, the intervention of GSS activated GR and Yap, in addition to promoting the proliferation of MDSCs, especially M-MDSCs. This further promoted the differentiation of Treg to enable immune tolerance, thus alleviating liver impairment. Therefore, it was proposed that GSS can alleviate AIH by modulating the innate immunity and adaptive T cell immunity, which may be the underlying mechanism for GSS to mitigate the liver impairment induced by AIH.

Myeloid-Derived Suppressor Cells in Solid Tumors

Myeloid-derived suppressor cells (MDSCs) are one of the main suppressive cell population of the immune system. They play a pivotal role in the establishment of the tumor microenvironment (TME). In the context of cancers or other pathological conditions, MDSCs can differentiate, expand, and migrate in large quantities during circulation, inhibiting the cytotoxic functions of T cells and NK cells. This process is regulated by ROS, iNOS/NO, arginase-1, and multiple soluble cytokines. The definition of MDSCs and their phenotypes in humans are not as well represented as in other organisms such as mice, owing to the absence of the cognate molecule. However, a comprehensive understanding of the differences between different species and subsets will be beneficial for clarifying the immunosuppressive properties and potential clinical values of these cells during tumor progression. Recently, experimental evidence and clinical investigations have demonstrated that MDSCs have a close relationship with poor prognosis and drug resistance, which is considered to be a leading marker for practical applications and therapeutic methods. In this review, we summarize the remarkable position of MDSCs in solid tumors, explain their classifications in different models, and introduce new treatment approaches to target MDSCs to better understand the advancement of new approaches to cancer treatment.

CCL5/CCR5 axis in human diseases and related treatments

To defense harmful stimuli or maintain the immune homeostasis, the body produces and recruits a superfamily of cytokines such as interleukins, interferons, chemokines etc. Among them, chemokines act as crucial regulators in defense systems. CCL5/CCR5 combination is known for facilitating inflammatory responses, as well as inducing the adhesion and migration of different T cell subsets in immune responses. In addition, recent studies have shown that the interaction between CCL5 and CCR5 is involved in various pathological processes including inflammation, chronic diseases, cancers as well as the infection of COVID-19. This review focuses on how CCL5/CCR5 axis participates in the pathological processes of different diseases and their relevant signaling pathways for the regulation of the axis. Moreover, we highlighted the gene therapy and chemotherapy studies for treating CCR5-related diseases, including the ongoing clinical trials. The barriers and perspectives for future application and translational research were also summarized.

Uncovering the Subtype-Specific Molecular Characteristics of Breast Cancer by Multiomics Analysis of Prognosis-Associated Genes, Driver Genes, Signaling Pathways, and Immune Activity

Breast cancer is a heterogeneous malignant disease with different prognoses and has been divided into four molecular subtypes. It is believed that molecular events occurring in breast stem/progenitor cells contribute to the carcinogenesis and development of different breast cancer subtypes. However, these subtype-specific molecular characteristics are largely unknown. In this study, we employed 1217 breast cancer samples from The Cancer Genome Atlas (TCGA) database for a multiomics analysis of the molecular characteristics of different breast cancer subtypes based on PAM50 algorithms. We detected the expression changes of subtype-specific genes and revealed that the expression of particular subtype-specific genes significantly affected prognosis. We also investigated the mutations and copy number variations (CNVs) of breast cancer driver genes and the representative genes of ten signaling pathways in different subtypes and revealed several subtype-specifically altered genes. Moreover, we detected the infiltration of various immune cells in different subtypes of breast cancer and showed that the infiltration levels of major immune cell types are different among these subtypes. Additionally, we investigated the factors affecting the immune infiltration level and the immune cytolytic activity in different breast cancer subtypes, namely, the mutation burden, genome instability and cancer-associated fibroblast (CAF) infiltration. This study may shed light on the molecular events contributing to carcinogenesis and development and provide potential markers and targets for the clinical diagnosis and treatment of different breast cancer subtypes.

Immunosenescence is both functional/adaptive and dysfunctional/maladaptive

Alterations in the immune system with aging are considered to underlie many age-related diseases. However, many elderly individuals remain healthy until even a very advanced age. There is also an increase in numbers of centenarians and their apparent fitness. We should therefore change our unilaterally detrimental consideration of age-related immune changes. Recent data taking into consideration the immunobiography concept may allow for meaningful distinctions among various aging trajectories. This implies that the aging immune system has a homeodynamic characteristic balanced between adaptive and maladaptive aspects. The survival and health of an individual depends from the equilibrium of this balance. In this article, we highlight which parts of the aging of the immune system may be considered adaptive in contrast to those that may be maladaptive.

The anti-inflammatory drug dimethyl itaconate protects against colitis-associated colorectal cancer

Colorectal cancer (CRC) is the third most common diagnosed cancer of which risk factors include unhealthy diet, smoking, and chronic inflammation. Weakening the inflammatory response emerges as an effective therapeutic strategy to prevent the progression of CRC. Inflammatory macrophages produce substantial amounts of immunoregulatory metabolite itaconate, which is synthesized by the immune response gene 1 (Irg1). In this study, we use a membrane-permeable itaconate derivative, dimethyl itaconate (DI), for the protection against CRC in mouse model. DI decreased the high inflammatory state of ulcerative colitis and reduced the colitis-associated cancer (CAC) risk. Mechanistically, DI inhibited the secretion of the cytokines IL-1β and CCL2 from intestinal epithelial cells, and therefore reduced the recruitment of macrophages into tumor microenvironment. Meanwhile, the decrease of macrophage infiltration was accompanied by a decrease of myeloid-derived suppressor cell (MDSC) infiltration and the differentiation of T cell subsets into cytotoxic T cells. We showed that itaconate derivative limits inflammatory response, indicating a negative feedback loop that involves an inflammatory agent and itaconate. Our findings demonstrate the potential application of DI for the prevention of colitis-associated CRC. KEY MESSAGES: Dimethyl itaconate (DI) suppresses ulcerative colitis and colitis-associated colorectal cancer DI decreases infiltration of macrophages and myeloid-derived suppressor cells into tumor DI weakens the inflammatory response via inhibiting the secretion of IL-1β and CCL2.

DNA methylation in the promoters of PD-L1, MMP9, ARG1, galectin-9, TIM-3, VISTA and TGF-β genes in HLA-DR- myeloid cells, compared with HLA-DR+ antigen-presenting cells

Myeloid cells, including antigen-presenting cells (APCs) and myeloid-derived suppressor cells (MDSCs) play opposing roles to orchestrate innate and adaptive immune responses during physiological and pathological conditions. We investigated the role of DNA methylation in regulating the transcription of inhibitory/suppressive molecules in myeloid suppressive cells (identified as CD33⁺HLA-DR^-) in comparison to APCs. We selected a number of immune checkpoints (ICs), IC ligands, and immunosuppressive molecules that have been implicated in MDSC function, including PD-L1, TIM-3, VISTA, galectin-9, TGF-β, ARG1 and MMP9. We examined their mRNA expression levels, and investigated whether DNA methylation regulates their transcription in sorted myeloid cell subpopulations. We found that mRNA levels of PD-L1, TIM-3, TGF-β, ARG1 and MMP9 in CD33⁺HLA-DR^- cells were higher than APCs. However, VISTA and galectin-9 mRNA levels were relatively similar in both myeloid subpopulations. CpG islands in the promoter regions of TGF-β1, TIM-3 and ARG1 were highly unmethylated in CD33⁺HLA-DR^-cells, compared with APCs, suggesting that DNA methylation is one of the key mechanisms, which regulate their expression. However, we did not find differences in the methylation status of PD-L1 and MMP9 between CD33⁺HLA-DR^- and APCs, suggesting that their transcription could be regulated via other genetic and epigenetic mechanisms. The promoter methylation status of VISTA was relatively similar in both myeloid subpopulations. This study provides novel insights into the epigenetic mechanisms, which control the expression of inhibitory/suppressive molecules in circulating CD33⁺HLA-DR^- cells in a steady-state condition, possibly to maintain immune tolerance and haemostasis.