Mesenchymal stromal/stem cell tissue source and in vitro expansion impact extracellular vesicle protein and miRNA compositions as well as angiogenic and immunomodulatory capacities.

Recently, therapies utilizing extracellular vesicles (EVs) derived from mesenchymal stromal/stem cells (MSCs) have begun to show promise in clinical trials. However, EV therapeutic potential varies with MSC tissue source and in vitro expansion through passaging. To find the optimal MSC source for clinically translatable EV-derived therapies, this study aims to compare the angiogenic and immunomodulatory potentials and the protein and miRNA cargo compositions of EVs isolated from the two most common clinical sources of adult MSCs, bone marrow and adipose tissue, across different passage numbers. Primary bone marrow-derived MSCs (BMSCs) and adipose-derived MSCs (ASCs) were isolated from adult female Lewis rats and expanded in vitro to the indicated passage numbers (P2, P4, and P8). EVs were isolated from the culture medium of P2, P4, and P8 BMSCs and ASCs and characterized for EV size, number, surface markers, protein content, and morphology. EVs isolated from different tissue sources showed different EV yields per cell, EV sizes, and protein yield per EV. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of proteomics data and miRNA seq data identified key proteins and pathways associated with differences between BMSC-EVs and ASC-EVs, as well as differences due to passage number. In vitro tube formation assays employing human umbilical vein endothelial cells suggested that both tissue source and passage number had significant effects on the angiogenic capacity of EVs. With or without lipopolysaccharide (LPS) stimulation, EVs more significantly impacted expression of M2-macrophage genes (IL-10, Arg1, TGFß) than M1-macrophage genes (IL-6, NOS2, TNFα). By correlating the proteomics analyses with the miRNA seq analysis and differences observed in our in vitro immunomodulatory, angiogenic, and proliferation assays, this study highlights the trade-offs that may be necessary in selecting the optimal MSC source for development of clinical EV therapies.

Culture and Immunomodulation of Equine Muscle-Derived Mesenchymal Stromal Cells: A Comparative Study of Innovative 2D versus 3D Models Using Equine Platelet Lysate.

Muscle-derived mesenchymal stromal cells (mdMSCs) hold great promise in regenerative medicine due to their immunomodulatory properties, multipotent differentiation capacity and ease of collection. However, traditional in vitro expansion methods use fetal bovine serum (FBS) and have numerous limitations including ethical concerns, batch-to-batch variability, immunogenicity, xenogenic contamination and regulatory compliance issues. This study investigates the use of 10% equine platelet lysate (ePL) obtained by plasmapheresis as a substitute for FBS in the culture of mdMSCs in innovative 2D and 3D models. Using muscle microbiopsies as the primary cell source in both models showed promising results. Initial investigations indicated that small variations in heparin concentration in 2D cultures strongly influenced medium coagulation with an optimal proliferation observed at final heparin concentrations of 1.44 IU/mL. The two novel models investigated showed that expansion of mdMSCs is achievable. At the end of expansion, the 3D model revealed a higher total number of cells harvested (64.60 ± 5.32 million) compared to the 2D culture (57.20 ± 7.66 million). Trilineage differentiation assays confirmed the multipotency (osteoblasts, chondroblasts and adipocytes) of the mdMSCs generated in both models with no significant difference observed. Immunophenotyping confirmed the expression of the mesenchymal stem cell (MSC) markers CD-90 and CD-44, with low expression of CD-45 and MHCII markers for mdMSCs derived from the two models. The generated mdMSCs also had great immunomodulatory properties. Specific immunological extraction followed by enzymatic detection (SIEFED) analysis demonstrated that mdMSCs from both models inhibited myeloperoxidase (MPO) activity in a strong dose-dependent manner. Moreover, they were also able to reduce reactive oxygen species (ROS) activity, with mdMSCs from the 3D model showing significantly higher dose-dependent inhibition compared to the 2D model. These results highlighted for the first time the feasibility and efficacy of using 10% ePL for mdMSC expansion in novel 2D and 3D approaches and also that mdMSCs have strong immunomodulatory properties that can be exploited to advance the field of regenerative medicine and cell therapy instead of using FBS with all its drawbacks.

Immunomodulatory effects of the induced pluripotent stem cells through expressing IGF-related factors and IL-10 in vitro.

BACKGROUND: Induced Pluripotent Stem Cells (IPSCs) represent an innovative strategy for addressing challenging diseases, including various rheumatologic conditions. Aside from their regenerative capacities, some studies have shown the potential of these cells in the modulation of inflammatory responses. The underlying mechanisms by which they exert their effects have yet to be fully comprehended. Therefore, we aimed to explore the gene expression linked to the IGF pathway as well as IL-10 and TGF-ß, which are known to exert immunomodulatory effects. METHODS: A C57/Bl6 pregnant mouse was used for obtaining mouse embryonic fibroblasts (MEFs), then the IPSCs were induced using lentiviral vectors expressing the pluripotency genes (OCT4, SOX2, KLF1, and c-MYC). Cells were cultured for 72 h in DMEM high glucose plus leukemia inhibitory factor; Evaluating the gene expression was conducted using specific primers for Igf1, Igf2, Igfbp3, Igfbp4, Irs1, Il-10, and Tgf-ß genes, as well as SYBR green qPCR master mix. The data were analyzed using the 2-ΔΔCT method and were compared by employing the t test; the results were plotted using GraphPad PRISM software. MEFs were utilized as controls. RESULTS: Gene expression analyses revealed that Igf-1, Igf-bp3, Igf-bp4, and Il-10 were significantly overexpressed (p ≤ .01), while Igf-2 and Tgf-b genes were significantly downregulated in the lysates from IPSCs in comparison with the control MEFs. The Irs1 gene expression was not altered significantly. CONCLUSION: IPSCs are potentially capable of modulating inflammatory responses through the expression of various anti-inflammatory mediators from the IGF signaling, as well as IL-10. This discovery uncovers a previously unknown dimension of IPSCs' therapeutic effects, potentially leading to more advanced in vivo research and subsequent clinical trials.

Immunomodulation aspects of gut microbiome-related interventional strategies in colorectal cancer.

Colorectal cancer (CRC), the third most common cancer worldwide, develops mainly due to the accumulation of genetic and epigenetic changes over many years. Substantial evidence suggests that gut microbiota plays a significant role in the initiation, progression, and control of CRC, depending on the balance between beneficial and pathogenic microorganisms. Nonetheless, gut microbiota composition by regulating the host immune response may either promote or inhibit CRC. Thus, modification of gut microbiota potentially impacts clinical outcomes of immunotherapy. Previous studies have indicated that therapeutic strategies such as probiotics, prebiotics, and postbiotics enhance the intestinal immune system and improve the efficacy of immunotherapeutic agents, potentially serving as a complementary strategy in cancer immunotherapy. This review discusses the role of the gut microbiota in the onset and development of CRC in relation to the immune response. Additionally, we focus on the effect of strategies manipulating gut microbiome on the immune response and efficacy of immunotherapy against CRC. We demonstrate that manipulation of gut microbiome can enhance immune response and outcomes of immunotherapy through downregulating Treg cells and other immunosuppressive cells while improving the function of T cells within the tumor; however, further research, especially clinical trials, are needed to evaluate its efficacy in cancer treatment.

The mechanism exploration of different colored rice for immunomodulation based on UPLC-Q-TOF, network pharmacology, and cell experiments.

Rice has a long history as a staple food consumed by half of the world's population. Compared with white rice (WR), colored rice (CR) has more nutritional value because it contains rich active ingredients. In this study, the potential mechanism of CR (red rice (RR), green rice (GR), black rice (BR), and purple rice (PR)) for immunomodulation was explored by UPLC-Q-TOF, network pharmacology, and cell experiment. kuromanin, kaempferol-3-O-arabinoside, keracyanin, guajavarin, and hispidulin in CR were the critical components for improving immunity. These ingredients are mainly found in BR. Cell experiments supported that kuromanin plays a role in maintaining immune homeostasis. In the normal environment, it promotes cell proliferation and improves DNA repair; In an inflammatory environment, it binds to AKT1 and reduces the release of inflammatory factors through the MAPK and NFKB signaling pathways. The study provides a guideline for humans to utilize the precise nutrition of CR.

Biopotency and surrogate assays to validate the immunomodulatory potency of extracellular vesicles derived from mesenchymal stem/stromal cells for the treatment of experimental autoimmune uveitis.

Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have been recognized as promising cytotherapeutics due to their demonstrated immunomodulatory effects in various preclinical models. The immunomodulatory capabilities of EVs stem from the proteins and genetic materials they carry from parent cells, but the cargo contents of EVs are significantly influenced by MSC tissues and donors, cellular age and culture conditions, resulting in functional variations. However, there are no surrogate assays available to validate the immunomodulatory potency of MSC-EVs before in vivo administration. In previous work, we discovered that microcarrier culture conditions enhance the immunomodulatory function of MSC-EVs, as well as the levels of immunosuppressive molecules such as TGF-ß1 and let-7b in MSC-EVs. Building on these findings, we investigated whether TGF-ß1 levels in MSC-EVs could serve as a surrogate biomarker for predicting their potency in vivo. Our studies revealed a strong correlation between TGF-ß1 and let-7b levels in MSC-EVs, as well as their capacity to suppress IFN-γ secretion in stimulated splenocytes, establishing biopotency and surrogate assays for MSC-EVs. Subsequently, we validated MSC-EVs generated from monolayer cultures (ML-EVs) or microcarrier cultures (MC-EVs) using murine models of experimental autoimmune uveoretinitis (EAU) and additional in vitro assays reflecting the Mode of Action of MSC-EVs in vivo. Our findings demonstrated that MC-EVs carrying high levels of TGF-ß1 exhibited greater efficacy than ML-EVs in halting disease progression in mice with EAU as well as inducing apoptosis and inhibiting the chemotaxis of retina-reactive T cells. Additionally, MSC-EVs suppressed the MAPK/ERK pathway in activated T cells, with treatment using TGF-ß1 or let-7b showing similar effects on the MAPK/ERK pathway. Collectively, our data suggest that MSC-EVs directly inhibit the infiltration of retina-reactive T cells toward the eyes, thereby halting the disease progression in EAU mice, and their immunomodulatory potency in vivo can be predicted by their TGF-ß1 levels.

Arylphthalide Delays Diabetic Retinopathy via Immunomodulating the Early Inflammatory Response in an Animal Model of Type 1 Diabetes Mellitus.

Diabetic retinopathy (DR) is one of the most prevalent secondary complications associated with diabetes. Specifically, Type 1 Diabetes Mellitus (T1D) has an immune component that may determine the evolution of DR by compromising the immune response of the retina, which is mediated by microglia. In the early stages of DR, the permeabilization of the blood-retinal barrier allows immune cells from the peripheral system to interact with the retinal immune system. The use of new bioactive molecules, such as 3-(2,4-dihydroxyphenyl)phthalide (M9), with powerful anti-inflammatory activity, might represent an advance in the treatment of diseases like DR by targeting the immune systems responsible for its onset and progression. Our research aimed to investigate the molecular mechanisms involved in the interaction of specific cells of the innate immune system during the progression of DR and the reduction in inflammatory processes contributing to the pathology. In vitro studies were conducted exposing Bv.2 microglial and Raw264.7 macrophage cells to proinflammatory stimuli for 24 h, in the presence or absence of M9. Ex vivo and in vivo approaches were performed in BB rats, an animal model for T1D. Retinal explants from BB rats were cultured with M9. Retinas from BB rats treated for 15 days with M9 via intraperitoneal injection were analyzed to determine survival, cellular signaling, and inflammatory markers using qPCR, Western blot, or immunofluorescence approaches. Retinal structure images were acquired via Spectral-Domain-Optical Coherence Tomography (SD-OCT). Our results show that the treatment with M9 significantly reduces inflammatory processes in in vitro, ex vivo, and in vivo models of DR. M9 works by inhibiting the proinflammatory responses during DR progression mainly affecting immune cell responses. It also induces an anti-inflammatory response, primarily mediated by microglial cells, leading to the synthesis of Arginase-1 and Hemeoxygenase-1(HO-1). Ultimately, in vivo administration of M9 preserves the retinal integrity from the degeneration associated with DR progression. Our findings demonstrate a specific interaction between both retinal and systemic immune cells in the progression of DR, with a differential response to treatment, mainly driven by microglia in the anti-inflammatory action. In vivo treatment with M9 induces a switch in immune cell phenotypes and functions that contributes to delaying the DR progression, positioning microglial cells as a new and specific therapeutic target in DR.

Biomimetic HA-GO implant coating for enhanced osseointegration via macrophage M2 polarization-induced osteo-immunomodulation.

The pro-inflammatory/anti-inflammatory polarized phenotypes of macrophages (M1/M2) can be used to predict the success of implant integration. Hence, activating and inducing the transformation of immunocytes that promote tissue repair appears to be a highly promising strategy for facilitating osteo-anagenesis. In a previous study, titanium implants were coated with a graphene oxide-hydroxyapatite (GO-HA) nanocomposite via electrophoretic deposition, and the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) was found to be significantly enhanced when the GO content was 2wt%. However, the effectiveness of the GO-HA nanocomposite coating in modifying the in vivo immune microenvironment still remains unclear. In this study, the effects of GO-HA coatings on osteogenesis were investigated based on the GO-HA-mediated immune regulation of macrophages. The HA-2wt%GO nanocomposite coatings exhibited good biocompatibility and favored M2 macrophage polarization. Meanwhile, they could also significantly upregulate IL-10 (anti-inflammatory factor) expression and downregulate TNF-α (pro-inflammatory factor) expression. Additionally, the microenvironment, which was established by M2 macrophages, favored the osteogenesis of BMSCs both in vivo and in vitro. These findings show that the GO-HA nanocomposite coating is a promising surface-modification material. Hence, this study provides a reference for the development of next-generation osteoimmunomodulatory biomaterials.

The YTH domain-containing protein family: Emerging players in immunomodulation and tumour immunotherapy targets.

BACKGROUND: The modification of N6-methyladenosine (m6A) plays a pivotal role in tumor by altering both innate and adaptive immune systems through various pathways, including the regulation of messenger RNA. The YTH domain protein family, acting as "readers" of m6A modifications, affects RNA splicing, stability, and immunogenicity, thereby playing essential roles in immune regulation and antitumor immunity. Despite their significance, the impact of the YTH domain protein family on tumor initiation and progression, as well as their involvement in tumor immune regulation and therapy, remains underexplored and lacks comprehensive review. CONCLUSION: This review introduces the molecular characteristics of the YTH domain protein family and their physiological and pathological roles in biological behavior, emphasizing their mechanisms in regulating immune responses and antitumor immunity. Additionally, the review discusses the roles of the YTH domain protein family in immune-related diseases and tumor resistance, highlighting that abnormal expression or dysfunction of YTH proteins is closely linked to tumor resistance. KEY POINTS: This review provides an in-depth understanding of the YTH domain protein family in immune regulation and antitumor immunity, suggesting new strategies and directions for immunotherapy of related diseases. These insights not only deepen our comprehension of m6A modifications and YTH protein functions but also pave the way for future research and clinical applications.

Polyphenol-Reinforced Glycocalyx-Like Hydrogel Coating Induced Myocardial Regeneration and Immunomodulation.

Although minimally invasive interventional occluders can effectively seal heart defect tissue, they still have some limitations, including poor endothelial healing, intense inflammatory response, and thrombosis formation. Herein, a polyphenol-reinforced medicine/peptide glycocalyx-like coating was prepared on cardiac occluders. A coating consisting of carboxylated chitosan, epigallocatechin-3-gallate (EGCG), tanshinone IIA sulfonic sodium (TSS), and hyaluronic acid grafted with 3-aminophenylboronic acid was prepared. Subsequently, the mercaptopropionic acid-GGGGG-Arg-Glu-Asp-Val peptide was grafted by the thiol-ene "click" reaction. The coating showed good hydrophilicity and free radical-scavenging ability and could release EGCG-TSS. The results of biological experiments suggested that the coating could reduce thrombosis by promoting endothelialization, and promote myocardial repair by regulating the inflammatory response. The functions of regulating cardiomyocyte apoptosis and metabolism were confirmed, and the inflammatory regulatory functions of the coating were mainly dependent on the NF-kappa B and TNF signaling pathway.

In vitro assessment of the immunomodulatory effects of probiotic Bacillus strains on chicken PBMCs.

The beneficial effects of feeding probiotic Bacillus subtilis DSM 32315 (BS) and Bacillus velezensis CECT 5940 (BV) to chickens in vivo are well-documented, with potential immune modulation as a key mechanism. In this study, we investigated the direct interactions of chicken peripheral blood mononuclear cells (PBMCs) with BS or BV in vitro through whole transcriptome profiling and cytokine array analysis. Transcriptome profiling revealed 20 significantly differentially expressed genes (DEGs) in response to both Bacillus treatments, with twelve DEGs identified in BS-treated PBMCs and eight in BV-treated PBMCs. Pathway analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated significant regulation of immune-related pathways by both BS and BV. Notably, BS treatment upregulated genes associated with immune cell surface markers (CD4, CD25, CD28), anti-inflammatory cytokine interleukin-10 (IL-10), and C-C motif chemokine ligand 5 (CCL5), while downregulating the gene encoding pro-inflammatory IL-16. BV treatment similarly affected genes associated with immune cell surface markers, IL-16, and CCL5, with no impact on the gene encoding IL-10. Both treatments induced higher expression of the gene encoding the avian ß-defensin 1 (AvBD1). The results of this in vitro study indicate an immunomodulatory effect of BS and BV in chicken PBMCs by regulating genes involved in anti-inflammatory, bacteriostatic, protective, and pro-inflammatory responses. Consequently, BS and BV may serve to augment the immune system's capacity to defend against infection by modulating immune responses and cytokine expression. Thus, the administration of these probiotics holds promise for reducing reliance on antimicrobials in farming practices.

Immunopeptides: immunomodulatory strategies and prospects for ocular immunity applications.

Immunopeptides have low toxicity, low immunogenicity and targeting, and broad application prospects in drug delivery and assembly, which are diverse in application strategies and drug combinations. Immunopeptides are particularly important for regulating ocular immune homeostasis, as the eye is an immune-privileged organ. Immunopeptides have advantages in adaptive immunity and innate immunity, treating eye immune-related diseases by regulating T cells, B cells, immune checkpoints, and cytokines. This article summarizes the application strategies of immunopeptides in innate immunity and adaptive immunity, including autoimmunity, infection, vaccine strategies, and tumors. Furthermore, it focuses on the mechanisms of immunopeptides in mediating ocular immunity (autoimmune diseases, inflammatory storms, and tumors). Moreover, it reviews immunopeptides' application strategies and the therapeutic potential of immunopeptides in the eye. We expect the immune peptide to get attention in treating eye diseases and to provide a direction for eye disease immune peptide research.

Vascular galectins in tumor angiogenesis and cancer immunity.

Sustained tumor angiogenesis, i.e., the induction and maintenance of blood vessel growth by tumor cells, is one of the hallmarks of cancer. The vascularization of malignant tissues not only facilitates tumor growth and metastasis, but also contributes to immune evasion. Important players in all these processes are the endothelial cells which line the luminal side of blood vessel. In the tumor vasculature, these cells are actively involved in angiogenesis as well in the hampered recruitment of immune cells. This is the result of the abnormal tumor microenvironment which triggers both angiostimulatory and immune inhibitory gene expression profiles in endothelial cells. In recent years, it has become evident that galectins constitute a protein family that is expressed in the tumor endothelium. Moreover, several members of this glycan-binding protein family have been found to facilitate tumor angiogenesis and stimulate immune suppression. All this has identified galectins as potential therapeutic targets to simultaneously hamper tumor angiogenesis and alleviate immune suppression. The current review provides a brief introduction in the human galectin protein family. The current knowledge regarding the expression and regulation of galectins in endothelial cells is summarized. Furthermore, an overview of the role that endothelial galectins play in tumor angiogenesis and tumor immunomodulation is provided. Finally, some outstanding questions are discussed that should be addressed by future research efforts. This will help to fully understand the contribution of endothelial galectins to tumor progression and to exploit endothelial galectins for cancer therapy.

Immunomodulatory effect of PLGA-encapsulated mesenchymal stem cells-derived exosomes for the treatment of allergic rhinitis.

Introduction: Allergic rhinitis (AR) is an upper airway inflammatory disease of the nasal mucosa. Conventional treatments such as symptomatic pharmacotherapy and allergen-specific immunotherapy have considerable limitations and drawbacks. As an emerging therapy with regenerative potential and immunomodulatory effect, mesenchymal stem cell-derived exosomes (MSC-Exos) have recently been trialed for the treatment of various inflammatory and autoimmune diseases. Methods: In order to achieve sustained and protected release of MSC-Exos for intranasal administration, we fabricated Poly(lactic-co-glycolic acid) (PLGA) micro and nanoparticles-encapsulated MSC-Exos (PLGA-Exos) using mechanical double emulsion for local treatment of AR. Preclinical in vivo imaging, ELISA, qPCR, flow cytometry, immunohistochemical staining, and multiomics sequencing were used for phenotypic and mechanistic evaluation of the therapeutic effect of PLGA-Exos in vitro and in vivo. Results: The results showed that our PLGA platform could efficiently encapsulate and release the exosomes in a sustained manner. At protein level, PLGA-Exos treatment upregulated IL-2, IL-10 and IFN-γ, and downregulated IL-4, IL-17 and antigen-specific IgE in ovalbumin (OVA)-induced AR mice. At cellular level, exosomes treatment reduced Th2 cells, increased Tregs, and reestablished Th1/Th2 balance. At tissue level, PLGA-Exos significantly attenuated the infiltration of immune cells (e.g., eosinophils and goblet cells) in nasal mucosa. Finally, multiomics analysis discovered several signaling cascades, e.g., peroxisome proliferator-activated receptor (PPAR) pathway and glycolysis pathway, that might mechanistically support the immunomodulatory effect of PLGA-Exos. Discussion: For the first time, we present a biomaterial-facilitated local delivery system for stem cell-derived exosomes as a novel and promising strategy for AR treatment.

The therapeutic potential of exosomes in immunotherapy.

Exosomes are found in various tissues of the body and carry abundant contents including nucleic acids, proteins, and metabolites, which continuously flow between cells of various tissues and mediate important intercellular communication. In addition, exosomes from different cellular sources possess different physiopathological immunomodulatory effects, which are closely related to the immune regeneration of normal or abnormal organs and tissues. Here, we focus on the mechanistic interactions between exosomes and the human immune system, introduce the immuno-regenerative therapeutic potential of exosomes in common clinical immune-related diseases, such as infectious diseases, autoimmune diseases, and tumors, and reveal the safety and efficacy of exosomes as a novel cell-free immune regenerative therapy.

Unlocking the Potential: immune functions of oligodendrocyte precursor cells.

Oligodendrocyte precursor cells (OPCs) have long been regarded as progenitors of oligodendrocytes, yet recent advances have illuminated their multifaceted nature including their emerging immune functions. This review seeks to shed light on the immune functions exhibited by OPCs, spanning from phagocytosis to immune modulation and direct engagement with immune cells across various pathological scenarios. Comprehensive understanding of the immune functions of OPCs alongside their other roles will pave the way for targeted therapies in neurological disorders.

An emerging maestro of immune regulation: how DOT1L orchestrates the harmonies of the immune system.

The immune system comprises a complex yet tightly regulated network of cells and molecules that play a critical role in protecting the body from infection and disease. The activity and development of each immune cell is regulated in a myriad of ways including through the cytokine milieu, the availability of key receptors, via tailored intracellular signalling cascades, dedicated transcription factors and even by directly modulating gene accessibility and expression; the latter is more commonly known as epigenetic regulation. In recent years, epigenetic regulators have begun to emerge as key players involved in modulating the immune system. Among these, the lysine methyltransferase DOT1L has gained significant attention for its involvement in orchestrating immune cell formation and function. In this review we provide an overview of the role of DOT1L across the immune system and the implications of this role on health and disease. We begin by elucidating the general mechanisms of DOT1L-mediated histone methylation and its impact on gene expression within immune cells. Subsequently, we provide a detailed and comprehensive overview of recent studies that identify DOT1L as a crucial regulator of immune cell development, differentiation, and activation. Next, we discuss the potential mechanisms of DOT1L-mediated regulation of immune cell function and shed light on how DOT1L might be contributing to immune cell homeostasis and dysfunction. We then provide food for thought by highlighting some of the current obstacles and technical limitations precluding a more in-depth elucidation of DOT1L's role. Finally, we explore the potential therapeutic implications of targeting DOT1L in the context of immune-related diseases and discuss ongoing research efforts to this end. Overall, this review consolidates the current paradigm regarding DOT1L's role across the immune network and emphasises its critical role in governing the healthy immune system and its potential as a novel therapeutic target for immune-related diseases. A deeper understanding of DOT1L's immunomodulatory functions could pave the way for innovative therapeutic approaches which fine-tune the immune response to enhance or restore human health.

The immunomodulatory ballet of tumour-derived extracellular vesicles and neutrophils orchestrating the dynamic CD73/PD-L1 pathway in cancer.

Head and neck squamous cell carcinoma (HNSCC) is a global cancer burden with a 5-year overall survival rate of around 50%, stagnant for decades. A tumour-induced immunosuppressive microenvironment contributes to HNSCC progression, with the adenosine (ADO) pathway and an upregulated expression of inhibitory immune checkpoint regulators playing a key role in this context. The correlation between high neutrophil-to-lymphocyte ratio (NLR) with advanced tumour staging suggests involvement of neutrophils (NØ) in cancer progression. Interestingly, we associated a high NLR with an increased intracellular PD-L1 localization in primary HNSCC samples, potentially mediating more aggressive tumour characteristics and therefore synergistically favouring tumour progression. Still, further research is needed to harness this knowledge for effective treatments and overcome resistance. Since it is hypothesized that the tumour microenvironment (TME) may be influenced by small extracellular vesicles (sEVs) secreted by tumours (TEX), this study aims to investigate the impact of HNSCC-derived TEX on NØ and blockade of ADO receptors as a potential strategy to reverse the pro-tumour phenotype of NØ. UMSCC47-TEX exhibited CD73 enzymatic activity involved in ADO signalling, as well as the immune checkpoint inhibitor PD-L1. Data revealed that TEX induce chemotaxis of NØ and the sustained interaction promotes a shift into a pro-tumour phenotype, dependent on ADO receptors (P1R), increasing CD170high subpopulation, CD73 and PD-L1 expression, followed by an immunosuppressive secretome. Blocking A3R reduced CD73 and PD-L1 expression. Co-culture experiments with HNSCC cells demonstrated that TEX-modulated NØ increase the CD73/PD-L1 axis, through Cyclin D-CDK4/6 signalling. To support these findings, the CAM model with primary tumour was treated with NØ supernatant. Moreover, these NØ promoted an increase in migration, invasion, and reduced cell death. Targeting P1R on NØ, particularly A3R, exhibited potential therapeutic strategy to counteract immunosuppression in HNSCC. Understanding the TEX-mediated crosstalk between tumours and NØ offers insights into immunomodulation for improving cancer therapies.

Human iPSC-liver organoid transplantation reduces fibrosis through immunomodulation.

Donor organ shortages for transplantation remain a serious global concern, and alternative treatment is in high demand. Fetal cells and tissues have considerable therapeutic potential as, for example, organoid technology that uses human induced pluripotent stem cells (hiPSCs) to generate unlimited human fetal-like cells and tissues. We previously reported the in vivo vascularization of early fetal liver-like hiPSC-derived liver buds (LBs) and subsquent improved survival of recipient mice with subacute liver failure. Here, we show hiPSC-liver organoids (LOs) that recapitulate midgestational fetal liver promote de novo liver generation when grafted onto the surface of host livers in chemical fibrosis models, thereby recovering liver function. We found that fetal liver, a hematopoietic tissue, highly expressed macrophage-recruiting factors and antifibrotic M2 macrophage polarization factors compared with the adult liver, resulting in fibrosis reduction because of CD163+ M2-macrophage polarization. Next, we created midgestational fetal liver-like hiPSC-LOs by fusion of hiPSC-LBs to induce static cell-cell interactions and found that these contained complex structures such as hepatocytes, vasculature, and bile ducts after transplantation. This fusion allowed the generation of a large human tissue suitable for transplantation into immunodeficient rodent models of liver fibrosis. hiPSC-LOs showed superior liver function compared with hiPSC-LBs and improved survival and liver function upon transplantation. In addition, hiPSC-LO transplantation ameliorated chemically induced liver fibrosis, a symptom of liver cirrhosis that leads to organ dysfunction, through immunomodulatory effects, particularly on CD163+ phagocytic M2-macrophage polarization. Together, our results suggest hiPSC-LO transplantation as a promising therapeutic option for liver fibrosis.

Fabrication of alginate composite hydrogel encapsulated retinoic acid and nano Se doped biphasic CaP to augment in situ mineralization and osteoimmunomodulation for bone regeneration.

BACKGROUND: Bone tissue engineering endows alternates to support bone defects/injuries that are circumscribed to undergo orchestrated process of remodeling on its own. In this regard, hydrogels have emerged as a promising platform that can confront irregular defects and encourage in situ bone repair. METHODS: In this study, we aimed to develop a new approach for bone tissue regeneration by developing an alginate based composite hydrogel incorporating selenium doped biphasic calcium phosphate nanoparticles, and retinoic acid. The fabricated hydrogel was physiochemically evaluated for morphological, bonding, and mechanical behavior. Additionally, the biological response of the fabricated hydrogel was evaluated on MC3T3-E1 pre-osteoblast cells. RESULTS: The developed composite hydrogel confers excellent biocompatibility, and osteoconductivity owing to the presence of alginate, and biphasic calcium phosphate, while selenium presents pro osteogenic, antioxidative, and immunomodulatory properties. The hydrogels exhibited highly porous microstructure, superior mechanical attributes, with enhanced calcification, and biomineralization abilities in vitro. SIGNIFICANCE: By combining the osteoconductive properties of biphasic calcium phosphate with multifaceted benefits of selenium and retinoic acid, the fabricated composite hydrogel offers a potential transformation in the landscape of bone defect treatment. This strategy could direct a versatile and effective approach to tackle complex bone injuries/defects and present potential for clinical translation.